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hush/shell/hush.c
Denys Vlasenko b347df9131 randomconfig fixes 
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2011-08-09 22:49:15 +02:00

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/* vi: set sw=4 ts=4: */
/*
* A prototype Bourne shell grammar parser.
* Intended to follow the original Thompson and Ritchie
* "small and simple is beautiful" philosophy, which
* incidentally is a good match to today's BusyBox.
*
* Copyright (C) 2000,2001 Larry Doolittle <larry@doolittle.boa.org>
* Copyright (C) 2008,2009 Denys Vlasenko <vda.linux@googlemail.com>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*
* Credits:
* The parser routines proper are all original material, first
* written Dec 2000 and Jan 2001 by Larry Doolittle. The
* execution engine, the builtins, and much of the underlying
* support has been adapted from busybox-0.49pre's lash, which is
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
* written by Erik Andersen <andersen@codepoet.org>. That, in turn,
* is based in part on ladsh.c, by Michael K. Johnson and Erik W.
* Troan, which they placed in the public domain. I don't know
* how much of the Johnson/Troan code has survived the repeated
* rewrites.
*
* Other credits:
* o_addchr derived from similar w_addchar function in glibc-2.2.
* parse_redirect, redirect_opt_num, and big chunks of main
* and many builtins derived from contributions by Erik Andersen.
* Miscellaneous bugfixes from Matt Kraai.
*
* There are two big (and related) architecture differences between
* this parser and the lash parser. One is that this version is
* actually designed from the ground up to understand nearly all
* of the Bourne grammar. The second, consequential change is that
* the parser and input reader have been turned inside out. Now,
* the parser is in control, and asks for input as needed. The old
* way had the input reader in control, and it asked for parsing to
* take place as needed. The new way makes it much easier to properly
* handle the recursion implicit in the various substitutions, especially
* across continuation lines.
*
* TODOs:
* grep for "TODO" and fix (some of them are easy)
* special variables (done: PWD, PPID, RANDOM)
* tilde expansion
* aliases
* follow IFS rules more precisely, including update semantics
* builtins mandated by standards we don't support:
* [un]alias, command, fc, getopts, newgrp, readonly, times
* make complex ${var%...} constructs support optional
* make here documents optional
*
* Bash compat TODO:
* redirection of stdout+stderr: &> and >&
* reserved words: function select
* advanced test: [[ ]]
* process substitution: <(list) and >(list)
* =~: regex operator
* let EXPR [EXPR...]
* Each EXPR is an arithmetic expression (ARITHMETIC EVALUATION)
* If the last arg evaluates to 0, let returns 1; 0 otherwise.
* NB: let `echo 'a=a + 1'` - error (IOW: multi-word expansion is used)
* ((EXPR))
* The EXPR is evaluated according to ARITHMETIC EVALUATION.
* This is exactly equivalent to let "EXPR".
* $[EXPR]: synonym for $((EXPR))
*
* Won't do:
* In bash, export builtin is special, its arguments are assignments
* and therefore expansion of them should be "one-word" expansion:
* $ export i=`echo 'a b'` # export has one arg: "i=a b"
* compare with:
* $ ls i=`echo 'a b'` # ls has two args: "i=a" and "b"
* ls: cannot access i=a: No such file or directory
* ls: cannot access b: No such file or directory
* Note1: same applies to local builtin.
* Note2: bash 3.2.33(1) does this only if export word itself
* is not quoted:
* $ export i=`echo 'aaa bbb'`; echo "$i"
* aaa bbb
* $ "export" i=`echo 'aaa bbb'`; echo "$i"
* aaa
*/
#if !(defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) \
|| defined(__APPLE__) \
)
# include <malloc.h> /* for malloc_trim */
#endif
#include <glob.h>
/* #include <dmalloc.h> */
#if ENABLE_HUSH_CASE
# include <fnmatch.h>
#endif
#include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */
#include "unicode.h"
#include "shell_common.h"
#include "math.h"
#include "match.h"
#if ENABLE_HUSH_RANDOM_SUPPORT
# include "random.h"
#else
# define CLEAR_RANDOM_T(rnd) ((void)0)
#endif
#ifndef PIPE_BUF
# define PIPE_BUF 4096 /* amount of buffering in a pipe */
#endif
/* Not every libc has sighandler_t. Fix it */
typedef void (*hush_sighandler_t)(int);
#define sighandler_t hush_sighandler_t
//config:config HUSH
//config: bool "hush"
//config: default y
//config: help
//config: hush is a small shell (25k). It handles the normal flow control
//config: constructs such as if/then/elif/else/fi, for/in/do/done, while loops,
//config: case/esac. Redirections, here documents, $((arithmetic))
//config: and functions are supported.
//config:
//config: It will compile and work on no-mmu systems.
//config:
//config: It does not handle select, aliases, tilde expansion,
//config: &>file and >&file redirection of stdout+stderr.
//config:
//config:config HUSH_BASH_COMPAT
//config: bool "bash-compatible extensions"
//config: default y
//config: depends on HUSH
//config: help
//config: Enable bash-compatible extensions.
//config:
//config:config HUSH_BRACE_EXPANSION
//config: bool "Brace expansion"
//config: default y
//config: depends on HUSH_BASH_COMPAT
//config: help
//config: Enable {abc,def} extension.
//config:
//config:config HUSH_HELP
//config: bool "help builtin"
//config: default y
//config: depends on HUSH
//config: help
//config: Enable help builtin in hush. Code size + ~1 kbyte.
//config:
//config:config HUSH_INTERACTIVE
//config: bool "Interactive mode"
//config: default y
//config: depends on HUSH
//config: help
//config: Enable interactive mode (prompt and command editing).
//config: Without this, hush simply reads and executes commands
//config: from stdin just like a shell script from a file.
//config: No prompt, no PS1/PS2 magic shell variables.
//config:
//config:config HUSH_SAVEHISTORY
//config: bool "Save command history to .hush_history"
//config: default y
//config: depends on HUSH_INTERACTIVE && FEATURE_EDITING_SAVEHISTORY
//config: help
//config: Enable history saving in hush.
//config:
//config:config HUSH_JOB
//config: bool "Job control"
//config: default y
//config: depends on HUSH_INTERACTIVE
//config: help
//config: Enable job control: Ctrl-Z backgrounds, Ctrl-C interrupts current
//config: command (not entire shell), fg/bg builtins work. Without this option,
//config: "cmd &" still works by simply spawning a process and immediately
//config: prompting for next command (or executing next command in a script),
//config: but no separate process group is formed.
//config:
//config:config HUSH_TICK
//config: bool "Process substitution"
//config: default y
//config: depends on HUSH
//config: help
//config: Enable process substitution `command` and $(command) in hush.
//config:
//config:config HUSH_IF
//config: bool "Support if/then/elif/else/fi"
//config: default y
//config: depends on HUSH
//config: help
//config: Enable if/then/elif/else/fi in hush.
//config:
//config:config HUSH_LOOPS
//config: bool "Support for, while and until loops"
//config: default y
//config: depends on HUSH
//config: help
//config: Enable for, while and until loops in hush.
//config:
//config:config HUSH_CASE
//config: bool "Support case ... esac statement"
//config: default y
//config: depends on HUSH
//config: help
//config: Enable case ... esac statement in hush. +400 bytes.
//config:
//config:config HUSH_FUNCTIONS
//config: bool "Support funcname() { commands; } syntax"
//config: default y
//config: depends on HUSH
//config: help
//config: Enable support for shell functions in hush. +800 bytes.
//config:
//config:config HUSH_LOCAL
//config: bool "Support local builtin"
//config: default y
//config: depends on HUSH_FUNCTIONS
//config: help
//config: Enable support for local variables in functions.
//config:
//config:config HUSH_RANDOM_SUPPORT
//config: bool "Pseudorandom generator and $RANDOM variable"
//config: default y
//config: depends on HUSH
//config: help
//config: Enable pseudorandom generator and dynamic variable "$RANDOM".
//config: Each read of "$RANDOM" will generate a new pseudorandom value.
//config:
//config:config HUSH_EXPORT_N
//config: bool "Support 'export -n' option"
//config: default y
//config: depends on HUSH
//config: help
//config: export -n unexports variables. It is a bash extension.
//config:
//config:config HUSH_MODE_X
//config: bool "Support 'hush -x' option and 'set -x' command"
//config: default y
//config: depends on HUSH
//config: help
//config: This instructs hush to print commands before execution.
//config: Adds ~300 bytes.
//config:
//config:config MSH
//config: bool "msh (deprecated: aliased to hush)"
//config: default n
//config: select HUSH
//config: help
//config: msh is deprecated and will be removed, please migrate to hush.
//config:
//applet:IF_HUSH(APPLET(hush, BB_DIR_BIN, BB_SUID_DROP))
//applet:IF_MSH(APPLET(msh, BB_DIR_BIN, BB_SUID_DROP))
//applet:IF_FEATURE_SH_IS_HUSH(APPLET_ODDNAME(sh, hush, BB_DIR_BIN, BB_SUID_DROP, sh))
//applet:IF_FEATURE_BASH_IS_HUSH(APPLET_ODDNAME(bash, hush, BB_DIR_BIN, BB_SUID_DROP, bash))
//kbuild:lib-$(CONFIG_HUSH) += hush.o match.o shell_common.o
//kbuild:lib-$(CONFIG_HUSH_RANDOM_SUPPORT) += random.o
/* -i (interactive) and -s (read stdin) are also accepted,
* but currently do nothing, therefore aren't shown in help.
* NOMMU-specific options are not meant to be used by users,
* therefore we don't show them either.
*/
//usage:#define hush_trivial_usage
//usage: "[-nxl] [-c 'SCRIPT' [ARG0 [ARGS]] / FILE [ARGS]]"
//usage:#define hush_full_usage "\n\n"
//usage: "Unix shell interpreter"
//usage:#define msh_trivial_usage hush_trivial_usage
//usage:#define msh_full_usage hush_full_usage
//usage:#if ENABLE_FEATURE_SH_IS_HUSH
//usage:# define sh_trivial_usage hush_trivial_usage
//usage:# define sh_full_usage hush_full_usage
//usage:#endif
//usage:#if ENABLE_FEATURE_BASH_IS_HUSH
//usage:# define bash_trivial_usage hush_trivial_usage
//usage:# define bash_full_usage hush_full_usage
//usage:#endif
/* Build knobs */
#define LEAK_HUNTING 0
#define BUILD_AS_NOMMU 0
/* Enable/disable sanity checks. Ok to enable in production,
* only adds a bit of bloat. Set to >1 to get non-production level verbosity.
* Keeping 1 for now even in released versions.
*/
#define HUSH_DEBUG 1
/* Slightly bigger (+200 bytes), but faster hush.
* So far it only enables a trick with counting SIGCHLDs and forks,
* which allows us to do fewer waitpid's.
* (we can detect a case where neither forks were done nor SIGCHLDs happened
* and therefore waitpid will return the same result as last time)
*/
#define ENABLE_HUSH_FAST 0
/* TODO: implement simplified code for users which do not need ${var%...} ops
* So far ${var%...} ops are always enabled:
*/
#define ENABLE_HUSH_DOLLAR_OPS 1
#if BUILD_AS_NOMMU
# undef BB_MMU
# undef USE_FOR_NOMMU
# undef USE_FOR_MMU
# define BB_MMU 0
# define USE_FOR_NOMMU(...) __VA_ARGS__
# define USE_FOR_MMU(...)
#endif
#include "NUM_APPLETS.h"
#if NUM_APPLETS == 1
/* STANDALONE does not make sense, and won't compile */
# undef CONFIG_FEATURE_SH_STANDALONE
# undef ENABLE_FEATURE_SH_STANDALONE
# undef IF_FEATURE_SH_STANDALONE
# undef IF_NOT_FEATURE_SH_STANDALONE
# define ENABLE_FEATURE_SH_STANDALONE 0
# define IF_FEATURE_SH_STANDALONE(...)
# define IF_NOT_FEATURE_SH_STANDALONE(...) __VA_ARGS__
#endif
#if !ENABLE_HUSH_INTERACTIVE
# undef ENABLE_FEATURE_EDITING
# define ENABLE_FEATURE_EDITING 0
# undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
# define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
#endif
/* Do we support ANY keywords? */
#if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
# define HAS_KEYWORDS 1
# define IF_HAS_KEYWORDS(...) __VA_ARGS__
# define IF_HAS_NO_KEYWORDS(...)
#else
# define HAS_KEYWORDS 0
# define IF_HAS_KEYWORDS(...)
# define IF_HAS_NO_KEYWORDS(...) __VA_ARGS__
#endif
/* If you comment out one of these below, it will be #defined later
* to perform debug printfs to stderr: */
#define debug_printf(...) do {} while (0)
/* Finer-grained debug switches */
#define debug_printf_parse(...) do {} while (0)
#define debug_print_tree(a, b) do {} while (0)
#define debug_printf_exec(...) do {} while (0)
#define debug_printf_env(...) do {} while (0)
#define debug_printf_jobs(...) do {} while (0)
#define debug_printf_expand(...) do {} while (0)
#define debug_printf_varexp(...) do {} while (0)
#define debug_printf_glob(...) do {} while (0)
#define debug_printf_list(...) do {} while (0)
#define debug_printf_subst(...) do {} while (0)
#define debug_printf_clean(...) do {} while (0)
#define ERR_PTR ((void*)(long)1)
#define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
#define _SPECIAL_VARS_STR "_*@$!?#"
#define SPECIAL_VARS_STR ("_*@$!?#" + 1)
#define NUMERIC_SPECVARS_STR ("_*@$!?#" + 3)
#if ENABLE_HUSH_BASH_COMPAT
/* Support / and // replace ops */
/* Note that // is stored as \ in "encoded" string representation */
# define VAR_ENCODED_SUBST_OPS "\\/%#:-=+?"
# define VAR_SUBST_OPS ("\\/%#:-=+?" + 1)
# define MINUS_PLUS_EQUAL_QUESTION ("\\/%#:-=+?" + 5)
#else
# define VAR_ENCODED_SUBST_OPS "%#:-=+?"
# define VAR_SUBST_OPS "%#:-=+?"
# define MINUS_PLUS_EQUAL_QUESTION ("%#:-=+?" + 3)
#endif
#define SPECIAL_VAR_SYMBOL 3
struct variable;
static const char hush_version_str[] ALIGN1 = "HUSH_VERSION="BB_VER;
/* This supports saving pointers malloced in vfork child,
* to be freed in the parent.
*/
#if !BB_MMU
typedef struct nommu_save_t {
char **new_env;
struct variable *old_vars;
char **argv;
char **argv_from_re_execing;
} nommu_save_t;
#endif
enum {
RES_NONE = 0,
#if ENABLE_HUSH_IF
RES_IF ,
RES_THEN ,
RES_ELIF ,
RES_ELSE ,
RES_FI ,
#endif
#if ENABLE_HUSH_LOOPS
RES_FOR ,
RES_WHILE ,
RES_UNTIL ,
RES_DO ,
RES_DONE ,
#endif
#if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
RES_IN ,
#endif
#if ENABLE_HUSH_CASE
RES_CASE ,
/* three pseudo-keywords support contrived "case" syntax: */
RES_CASE_IN, /* "case ... IN", turns into RES_MATCH when IN is observed */
RES_MATCH , /* "word)" */
RES_CASE_BODY, /* "this command is inside CASE" */
RES_ESAC ,
#endif
RES_XXXX ,
RES_SNTX
};
typedef struct o_string {
char *data;
int length; /* position where data is appended */
int maxlen;
int o_expflags;
/* At least some part of the string was inside '' or "",
* possibly empty one: word"", wo''rd etc. */
smallint has_quoted_part;
smallint has_empty_slot;
smallint o_assignment; /* 0:maybe, 1:yes, 2:no */
} o_string;
enum {
EXP_FLAG_SINGLEWORD = 0x80, /* must be 0x80 */
EXP_FLAG_GLOB = 0x2,
/* Protect newly added chars against globbing
* by prepending \ to *, ?, [, \ */
EXP_FLAG_ESC_GLOB_CHARS = 0x1,
};
enum {
MAYBE_ASSIGNMENT = 0,
DEFINITELY_ASSIGNMENT = 1,
NOT_ASSIGNMENT = 2,
/* Not an assigment, but next word may be: "if v=xyz cmd;" */
WORD_IS_KEYWORD = 3,
};
/* Used for initialization: o_string foo = NULL_O_STRING; */
#define NULL_O_STRING { NULL }
#ifndef debug_printf_parse
static const char *const assignment_flag[] = {
"MAYBE_ASSIGNMENT",
"DEFINITELY_ASSIGNMENT",
"NOT_ASSIGNMENT",
"WORD_IS_KEYWORD",
};
#endif
typedef struct in_str {
const char *p;
/* eof_flag=1: last char in ->p is really an EOF */
char eof_flag; /* meaningless if ->p == NULL */
char peek_buf[2];
#if ENABLE_HUSH_INTERACTIVE
smallint promptmode; /* 0: PS1, 1: PS2 */
#endif
int last_char;
FILE *file;
int (*get) (struct in_str *) FAST_FUNC;
int (*peek) (struct in_str *) FAST_FUNC;
} in_str;
#define i_getch(input) ((input)->get(input))
#define i_peek(input) ((input)->peek(input))
/* The descrip member of this structure is only used to make
* debugging output pretty */
static const struct {
int mode;
signed char default_fd;
char descrip[3];
} redir_table[] = {
{ O_RDONLY, 0, "<" },
{ O_CREAT|O_TRUNC|O_WRONLY, 1, ">" },
{ O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
{ O_CREAT|O_RDWR, 1, "<>" },
{ O_RDONLY, 0, "<<" },
/* Should not be needed. Bogus default_fd helps in debugging */
/* { O_RDONLY, 77, "<<" }, */
};
struct redir_struct {
struct redir_struct *next;
char *rd_filename; /* filename */
int rd_fd; /* fd to redirect */
/* fd to redirect to, or -3 if rd_fd is to be closed (n>&-) */
int rd_dup;
smallint rd_type; /* (enum redir_type) */
/* note: for heredocs, rd_filename contains heredoc delimiter,
* and subsequently heredoc itself; and rd_dup is a bitmask:
* bit 0: do we need to trim leading tabs?
* bit 1: is heredoc quoted (<<'delim' syntax) ?
*/
};
typedef enum redir_type {
REDIRECT_INPUT = 0,
REDIRECT_OVERWRITE = 1,
REDIRECT_APPEND = 2,
REDIRECT_IO = 3,
REDIRECT_HEREDOC = 4,
REDIRECT_HEREDOC2 = 5, /* REDIRECT_HEREDOC after heredoc is loaded */
REDIRFD_CLOSE = -3,
REDIRFD_SYNTAX_ERR = -2,
REDIRFD_TO_FILE = -1,
/* otherwise, rd_fd is redirected to rd_dup */
HEREDOC_SKIPTABS = 1,
HEREDOC_QUOTED = 2,
} redir_type;
struct command {
pid_t pid; /* 0 if exited */
int assignment_cnt; /* how many argv[i] are assignments? */
smallint is_stopped; /* is the command currently running? */
smallint cmd_type; /* CMD_xxx */
#define CMD_NORMAL 0
#define CMD_SUBSHELL 1
#if ENABLE_HUSH_BASH_COMPAT
/* used for "[[ EXPR ]]" */
# define CMD_SINGLEWORD_NOGLOB 2
#endif
#if ENABLE_HUSH_FUNCTIONS
# define CMD_FUNCDEF 3
#endif
smalluint cmd_exitcode;
/* if non-NULL, this "command" is { list }, ( list ), or a compound statement */
struct pipe *group;
#if !BB_MMU
char *group_as_string;
#endif
#if ENABLE_HUSH_FUNCTIONS
struct function *child_func;
/* This field is used to prevent a bug here:
* while...do f1() {a;}; f1; f1() {b;}; f1; done
* When we execute "f1() {a;}" cmd, we create new function and clear
* cmd->group, cmd->group_as_string, cmd->argv[0].
* When we execute "f1() {b;}", we notice that f1 exists,
* and that its "parent cmd" struct is still "alive",
* we put those fields back into cmd->xxx
* (struct function has ->parent_cmd ptr to facilitate that).
* When we loop back, we can execute "f1() {a;}" again and set f1 correctly.
* Without this trick, loop would execute a;b;b;b;...
* instead of correct sequence a;b;a;b;...
* When command is freed, it severs the link
* (sets ->child_func->parent_cmd to NULL).
*/
#endif
char **argv; /* command name and arguments */
/* argv vector may contain variable references (^Cvar^C, ^C0^C etc)
* and on execution these are substituted with their values.
* Substitution can make _several_ words out of one argv[n]!
* Example: argv[0]=='.^C*^C.' here: echo .$*.
* References of the form ^C`cmd arg^C are `cmd arg` substitutions.
*/
struct redir_struct *redirects; /* I/O redirections */
};
/* Is there anything in this command at all? */
#define IS_NULL_CMD(cmd) \
(!(cmd)->group && !(cmd)->argv && !(cmd)->redirects)
struct pipe {
struct pipe *next;
int num_cmds; /* total number of commands in pipe */
int alive_cmds; /* number of commands running (not exited) */
int stopped_cmds; /* number of commands alive, but stopped */
#if ENABLE_HUSH_JOB
int jobid; /* job number */
pid_t pgrp; /* process group ID for the job */
char *cmdtext; /* name of job */
#endif
struct command *cmds; /* array of commands in pipe */
smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
IF_HAS_KEYWORDS(smallint pi_inverted;) /* "! cmd | cmd" */
IF_HAS_KEYWORDS(smallint res_word;) /* needed for if, for, while, until... */
};
typedef enum pipe_style {
PIPE_SEQ = 1,
PIPE_AND = 2,
PIPE_OR = 3,
PIPE_BG = 4,
} pipe_style;
/* Is there anything in this pipe at all? */
#define IS_NULL_PIPE(pi) \
((pi)->num_cmds == 0 IF_HAS_KEYWORDS( && (pi)->res_word == RES_NONE))
/* This holds pointers to the various results of parsing */
struct parse_context {
/* linked list of pipes */
struct pipe *list_head;
/* last pipe (being constructed right now) */
struct pipe *pipe;
/* last command in pipe (being constructed right now) */
struct command *command;
/* last redirect in command->redirects list */
struct redir_struct *pending_redirect;
#if !BB_MMU
o_string as_string;
#endif
#if HAS_KEYWORDS
smallint ctx_res_w;
smallint ctx_inverted; /* "! cmd | cmd" */
#if ENABLE_HUSH_CASE
smallint ctx_dsemicolon; /* ";;" seen */
#endif
/* bitmask of FLAG_xxx, for figuring out valid reserved words */
int old_flag;
/* group we are enclosed in:
* example: "if pipe1; pipe2; then pipe3; fi"
* when we see "if" or "then", we malloc and copy current context,
* and make ->stack point to it. then we parse pipeN.
* when closing "then" / fi" / whatever is found,
* we move list_head into ->stack->command->group,
* copy ->stack into current context, and delete ->stack.
* (parsing of { list } and ( list ) doesn't use this method)
*/
struct parse_context *stack;
#endif
};
/* On program start, environ points to initial environment.
* putenv adds new pointers into it, unsetenv removes them.
* Neither of these (de)allocates the strings.
* setenv allocates new strings in malloc space and does putenv,
* and thus setenv is unusable (leaky) for shell's purposes */
#define setenv(...) setenv_is_leaky_dont_use()
struct variable {
struct variable *next;
char *varstr; /* points to "name=" portion */
#if ENABLE_HUSH_LOCAL
unsigned func_nest_level;
#endif
int max_len; /* if > 0, name is part of initial env; else name is malloced */
smallint flg_export; /* putenv should be done on this var */
smallint flg_read_only;
};
enum {
BC_BREAK = 1,
BC_CONTINUE = 2,
};
#if ENABLE_HUSH_FUNCTIONS
struct function {
struct function *next;
char *name;
struct command *parent_cmd;
struct pipe *body;
# if !BB_MMU
char *body_as_string;
# endif
};
#endif
/* set -/+o OPT support. (TODO: make it optional)
* bash supports the following opts:
* allexport off
* braceexpand on
* emacs on
* errexit off
* errtrace off
* functrace off
* hashall on
* histexpand off
* history on
* ignoreeof off
* interactive-comments on
* keyword off
* monitor on
* noclobber off
* noexec off
* noglob off
* nolog off
* notify off
* nounset off
* onecmd off
* physical off
* pipefail off
* posix off
* privileged off
* verbose off
* vi off
* xtrace off
*/
static const char o_opt_strings[] ALIGN1 =
"pipefail\0"
"noexec\0"
#if ENABLE_HUSH_MODE_X
"xtrace\0"
#endif
;
enum {
OPT_O_PIPEFAIL,
OPT_O_NOEXEC,
#if ENABLE_HUSH_MODE_X
OPT_O_XTRACE,
#endif
NUM_OPT_O
};
/* "Globals" within this file */
/* Sorted roughly by size (smaller offsets == smaller code) */
struct globals {
/* interactive_fd != 0 means we are an interactive shell.
* If we are, then saved_tty_pgrp can also be != 0, meaning
* that controlling tty is available. With saved_tty_pgrp == 0,
* job control still works, but terminal signals
* (^C, ^Z, ^Y, ^\) won't work at all, and background
* process groups can only be created with "cmd &".
* With saved_tty_pgrp != 0, hush will use tcsetpgrp()
* to give tty to the foreground process group,
* and will take it back when the group is stopped (^Z)
* or killed (^C).
*/
#if ENABLE_HUSH_INTERACTIVE
/* 'interactive_fd' is a fd# open to ctty, if we have one
* _AND_ if we decided to act interactively */
int interactive_fd;
const char *PS1;
const char *PS2;
# define G_interactive_fd (G.interactive_fd)
#else
# define G_interactive_fd 0
#endif
#if ENABLE_FEATURE_EDITING
line_input_t *line_input_state;
#endif
pid_t root_pid;
pid_t root_ppid;
pid_t last_bg_pid;
#if ENABLE_HUSH_RANDOM_SUPPORT
random_t random_gen;
#endif
#if ENABLE_HUSH_JOB
int run_list_level;
int last_jobid;
pid_t saved_tty_pgrp;
struct pipe *job_list;
# define G_saved_tty_pgrp (G.saved_tty_pgrp)
#else
# define G_saved_tty_pgrp 0
#endif
char o_opt[NUM_OPT_O];
#if ENABLE_HUSH_MODE_X
# define G_x_mode (G.o_opt[OPT_O_XTRACE])
#else
# define G_x_mode 0
#endif
smallint flag_SIGINT;
#if ENABLE_HUSH_LOOPS
smallint flag_break_continue;
#endif
#if ENABLE_HUSH_FUNCTIONS
/* 0: outside of a function (or sourced file)
* -1: inside of a function, ok to use return builtin
* 1: return is invoked, skip all till end of func
*/
smallint flag_return_in_progress;
#endif
smallint exiting; /* used to prevent EXIT trap recursion */
/* These four support $?, $#, and $1 */
smalluint last_exitcode;
/* are global_argv and global_argv[1..n] malloced? (note: not [0]) */
smalluint global_args_malloced;
/* how many non-NULL argv's we have. NB: $# + 1 */
int global_argc;
char **global_argv;
#if !BB_MMU
char *argv0_for_re_execing;
#endif
#if ENABLE_HUSH_LOOPS
unsigned depth_break_continue;
unsigned depth_of_loop;
#endif
const char *ifs;
const char *cwd;
struct variable *top_var;
char **expanded_assignments;
#if ENABLE_HUSH_FUNCTIONS
struct function *top_func;
# if ENABLE_HUSH_LOCAL
struct variable **shadowed_vars_pp;
unsigned func_nest_level;
# endif
#endif
/* Signal and trap handling */
#if ENABLE_HUSH_FAST
unsigned count_SIGCHLD;
unsigned handled_SIGCHLD;
smallint we_have_children;
#endif
/* Which signals have non-DFL handler (even with no traps set)?
* Set at the start to:
* (SIGQUIT + maybe SPECIAL_INTERACTIVE_SIGS + maybe SPECIAL_JOBSTOP_SIGS)
* SPECIAL_INTERACTIVE_SIGS are cleared after fork.
* The rest is cleared right before execv syscalls.
* Other than these two times, never modified.
*/
unsigned special_sig_mask;
#if ENABLE_HUSH_JOB
unsigned fatal_sig_mask;
# define G_fatal_sig_mask G.fatal_sig_mask
#else
# define G_fatal_sig_mask 0
#endif
char **traps; /* char *traps[NSIG] */
sigset_t pending_set;
#if HUSH_DEBUG
unsigned long memleak_value;
int debug_indent;
#endif
struct sigaction sa;
char user_input_buf[ENABLE_FEATURE_EDITING ? CONFIG_FEATURE_EDITING_MAX_LEN : 2];
};
#define G (*ptr_to_globals)
/* Not #defining name to G.name - this quickly gets unwieldy
* (too many defines). Also, I actually prefer to see when a variable
* is global, thus "G." prefix is a useful hint */
#define INIT_G() do { \
SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
/* memset(&G.sa, 0, sizeof(G.sa)); */ \
sigfillset(&G.sa.sa_mask); \
G.sa.sa_flags = SA_RESTART; \
} while (0)
/* Function prototypes for builtins */
static int builtin_cd(char **argv) FAST_FUNC;
static int builtin_echo(char **argv) FAST_FUNC;
static int builtin_eval(char **argv) FAST_FUNC;
static int builtin_exec(char **argv) FAST_FUNC;
static int builtin_exit(char **argv) FAST_FUNC;
static int builtin_export(char **argv) FAST_FUNC;
#if ENABLE_HUSH_JOB
static int builtin_fg_bg(char **argv) FAST_FUNC;
static int builtin_jobs(char **argv) FAST_FUNC;
#endif
#if ENABLE_HUSH_HELP
static int builtin_help(char **argv) FAST_FUNC;
#endif
#if ENABLE_HUSH_LOCAL
static int builtin_local(char **argv) FAST_FUNC;
#endif
#if HUSH_DEBUG
static int builtin_memleak(char **argv) FAST_FUNC;
#endif
#if ENABLE_PRINTF
static int builtin_printf(char **argv) FAST_FUNC;
#endif
static int builtin_pwd(char **argv) FAST_FUNC;
static int builtin_read(char **argv) FAST_FUNC;
static int builtin_set(char **argv) FAST_FUNC;
static int builtin_shift(char **argv) FAST_FUNC;
static int builtin_source(char **argv) FAST_FUNC;
static int builtin_test(char **argv) FAST_FUNC;
static int builtin_trap(char **argv) FAST_FUNC;
static int builtin_type(char **argv) FAST_FUNC;
static int builtin_true(char **argv) FAST_FUNC;
static int builtin_umask(char **argv) FAST_FUNC;
static int builtin_unset(char **argv) FAST_FUNC;
static int builtin_wait(char **argv) FAST_FUNC;
#if ENABLE_HUSH_LOOPS
static int builtin_break(char **argv) FAST_FUNC;
static int builtin_continue(char **argv) FAST_FUNC;
#endif
#if ENABLE_HUSH_FUNCTIONS
static int builtin_return(char **argv) FAST_FUNC;
#endif
/* Table of built-in functions. They can be forked or not, depending on
* context: within pipes, they fork. As simple commands, they do not.
* When used in non-forking context, they can change global variables
* in the parent shell process. If forked, of course they cannot.
* For example, 'unset foo | whatever' will parse and run, but foo will
* still be set at the end. */
struct built_in_command {
const char *b_cmd;
int (*b_function)(char **argv) FAST_FUNC;
#if ENABLE_HUSH_HELP
const char *b_descr;
# define BLTIN(cmd, func, help) { cmd, func, help }
#else
# define BLTIN(cmd, func, help) { cmd, func }
#endif
};
static const struct built_in_command bltins1[] = {
BLTIN("." , builtin_source , "Run commands in a file"),
BLTIN(":" , builtin_true , NULL),
#if ENABLE_HUSH_JOB
BLTIN("bg" , builtin_fg_bg , "Resume a job in the background"),
#endif
#if ENABLE_HUSH_LOOPS
BLTIN("break" , builtin_break , "Exit from a loop"),
#endif
BLTIN("cd" , builtin_cd , "Change directory"),
#if ENABLE_HUSH_LOOPS
BLTIN("continue" , builtin_continue, "Start new loop iteration"),
#endif
BLTIN("eval" , builtin_eval , "Construct and run shell command"),
BLTIN("exec" , builtin_exec , "Execute command, don't return to shell"),
BLTIN("exit" , builtin_exit , "Exit"),
BLTIN("export" , builtin_export , "Set environment variables"),
#if ENABLE_HUSH_JOB
BLTIN("fg" , builtin_fg_bg , "Bring job into the foreground"),
#endif
#if ENABLE_HUSH_HELP
BLTIN("help" , builtin_help , NULL),
#endif
#if ENABLE_HUSH_JOB
BLTIN("jobs" , builtin_jobs , "List jobs"),
#endif
#if ENABLE_HUSH_LOCAL
BLTIN("local" , builtin_local , "Set local variables"),
#endif
#if HUSH_DEBUG
BLTIN("memleak" , builtin_memleak , NULL),
#endif
BLTIN("read" , builtin_read , "Input into variable"),
#if ENABLE_HUSH_FUNCTIONS
BLTIN("return" , builtin_return , "Return from a function"),
#endif
BLTIN("set" , builtin_set , "Set/unset positional parameters"),
BLTIN("shift" , builtin_shift , "Shift positional parameters"),
#if ENABLE_HUSH_BASH_COMPAT
BLTIN("source" , builtin_source , "Run commands in a file"),
#endif
BLTIN("trap" , builtin_trap , "Trap signals"),
BLTIN("type" , builtin_type , "Show command type"),
BLTIN("ulimit" , shell_builtin_ulimit , "Control resource limits"),
BLTIN("umask" , builtin_umask , "Set file creation mask"),
BLTIN("unset" , builtin_unset , "Unset variables"),
BLTIN("wait" , builtin_wait , "Wait for process"),
};
/* For now, echo and test are unconditionally enabled.
* Maybe make it configurable? */
static const struct built_in_command bltins2[] = {
BLTIN("[" , builtin_test , NULL),
BLTIN("echo" , builtin_echo , NULL),
#if ENABLE_PRINTF
BLTIN("printf" , builtin_printf , NULL),
#endif
BLTIN("pwd" , builtin_pwd , NULL),
BLTIN("test" , builtin_test , NULL),
};
/* Debug printouts.
*/
#if HUSH_DEBUG
/* prevent disasters with G.debug_indent < 0 */
# define indent() fdprintf(2, "%*s", (G.debug_indent * 2) & 0xff, "")
# define debug_enter() (G.debug_indent++)
# define debug_leave() (G.debug_indent--)
#else
# define indent() ((void)0)
# define debug_enter() ((void)0)
# define debug_leave() ((void)0)
#endif
#ifndef debug_printf
# define debug_printf(...) (indent(), fdprintf(2, __VA_ARGS__))
#endif
#ifndef debug_printf_parse
# define debug_printf_parse(...) (indent(), fdprintf(2, __VA_ARGS__))
#endif
#ifndef debug_printf_exec
#define debug_printf_exec(...) (indent(), fdprintf(2, __VA_ARGS__))
#endif
#ifndef debug_printf_env
# define debug_printf_env(...) (indent(), fdprintf(2, __VA_ARGS__))
#endif
#ifndef debug_printf_jobs
# define debug_printf_jobs(...) (indent(), fdprintf(2, __VA_ARGS__))
# define DEBUG_JOBS 1
#else
# define DEBUG_JOBS 0
#endif
#ifndef debug_printf_expand
# define debug_printf_expand(...) (indent(), fdprintf(2, __VA_ARGS__))
# define DEBUG_EXPAND 1
#else
# define DEBUG_EXPAND 0
#endif
#ifndef debug_printf_varexp
# define debug_printf_varexp(...) (indent(), fdprintf(2, __VA_ARGS__))
#endif
#ifndef debug_printf_glob
# define debug_printf_glob(...) (indent(), fdprintf(2, __VA_ARGS__))
# define DEBUG_GLOB 1
#else
# define DEBUG_GLOB 0
#endif
#ifndef debug_printf_list
# define debug_printf_list(...) (indent(), fdprintf(2, __VA_ARGS__))
#endif
#ifndef debug_printf_subst
# define debug_printf_subst(...) (indent(), fdprintf(2, __VA_ARGS__))
#endif
#ifndef debug_printf_clean
# define debug_printf_clean(...) (indent(), fdprintf(2, __VA_ARGS__))
# define DEBUG_CLEAN 1
#else
# define DEBUG_CLEAN 0
#endif
#if DEBUG_EXPAND
static void debug_print_strings(const char *prefix, char **vv)
{
indent();
fdprintf(2, "%s:\n", prefix);
while (*vv)
fdprintf(2, " '%s'\n", *vv++);
}
#else
# define debug_print_strings(prefix, vv) ((void)0)
#endif
/* Leak hunting. Use hush_leaktool.sh for post-processing.
*/
#if LEAK_HUNTING
static void *xxmalloc(int lineno, size_t size)
{
void *ptr = xmalloc((size + 0xff) & ~0xff);
fdprintf(2, "line %d: malloc %p\n", lineno, ptr);
return ptr;
}
static void *xxrealloc(int lineno, void *ptr, size_t size)
{
ptr = xrealloc(ptr, (size + 0xff) & ~0xff);
fdprintf(2, "line %d: realloc %p\n", lineno, ptr);
return ptr;
}
static char *xxstrdup(int lineno, const char *str)
{
char *ptr = xstrdup(str);
fdprintf(2, "line %d: strdup %p\n", lineno, ptr);
return ptr;
}
static void xxfree(void *ptr)
{
fdprintf(2, "free %p\n", ptr);
free(ptr);
}
# define xmalloc(s) xxmalloc(__LINE__, s)
# define xrealloc(p, s) xxrealloc(__LINE__, p, s)
# define xstrdup(s) xxstrdup(__LINE__, s)
# define free(p) xxfree(p)
#endif
/* Syntax and runtime errors. They always abort scripts.
* In interactive use they usually discard unparsed and/or unexecuted commands
* and return to the prompt.
* HUSH_DEBUG >= 2 prints line number in this file where it was detected.
*/
#if HUSH_DEBUG < 2
# define die_if_script(lineno, ...) die_if_script(__VA_ARGS__)
# define syntax_error(lineno, msg) syntax_error(msg)
# define syntax_error_at(lineno, msg) syntax_error_at(msg)
# define syntax_error_unterm_ch(lineno, ch) syntax_error_unterm_ch(ch)
# define syntax_error_unterm_str(lineno, s) syntax_error_unterm_str(s)
# define syntax_error_unexpected_ch(lineno, ch) syntax_error_unexpected_ch(ch)
#endif
static void die_if_script(unsigned lineno, const char *fmt, ...)
{
va_list p;
#if HUSH_DEBUG >= 2
bb_error_msg("hush.c:%u", lineno);
#endif
va_start(p, fmt);
bb_verror_msg(fmt, p, NULL);
va_end(p);
if (!G_interactive_fd)
xfunc_die();
}
static void syntax_error(unsigned lineno UNUSED_PARAM, const char *msg)
{
if (msg)
bb_error_msg("syntax error: %s", msg);
else
bb_error_msg("syntax error");
}
static void syntax_error_at(unsigned lineno UNUSED_PARAM, const char *msg)
{
bb_error_msg("syntax error at '%s'", msg);
}
static void syntax_error_unterm_str(unsigned lineno UNUSED_PARAM, const char *s)
{
bb_error_msg("syntax error: unterminated %s", s);
}
static void syntax_error_unterm_ch(unsigned lineno, char ch)
{
char msg[2] = { ch, '\0' };
syntax_error_unterm_str(lineno, msg);
}
static void syntax_error_unexpected_ch(unsigned lineno UNUSED_PARAM, int ch)
{
char msg[2];
msg[0] = ch;
msg[1] = '\0';
bb_error_msg("syntax error: unexpected %s", ch == EOF ? "EOF" : msg);
}
#if HUSH_DEBUG < 2
# undef die_if_script
# undef syntax_error
# undef syntax_error_at
# undef syntax_error_unterm_ch
# undef syntax_error_unterm_str
# undef syntax_error_unexpected_ch
#else
# define die_if_script(...) die_if_script(__LINE__, __VA_ARGS__)
# define syntax_error(msg) syntax_error(__LINE__, msg)
# define syntax_error_at(msg) syntax_error_at(__LINE__, msg)
# define syntax_error_unterm_ch(ch) syntax_error_unterm_ch(__LINE__, ch)
# define syntax_error_unterm_str(s) syntax_error_unterm_str(__LINE__, s)
# define syntax_error_unexpected_ch(ch) syntax_error_unexpected_ch(__LINE__, ch)
#endif
#if ENABLE_HUSH_INTERACTIVE
static void cmdedit_update_prompt(void);
#else
# define cmdedit_update_prompt() ((void)0)
#endif
/* Utility functions
*/
/* Replace each \x with x in place, return ptr past NUL. */
static char *unbackslash(char *src)
{
char *dst = src = strchrnul(src, '\\');
while (1) {
if (*src == '\\')
src++;
if ((*dst++ = *src++) == '\0')
break;
}
return dst;
}
static char **add_strings_to_strings(char **strings, char **add, int need_to_dup)
{
int i;
unsigned count1;
unsigned count2;
char **v;
v = strings;
count1 = 0;
if (v) {
while (*v) {
count1++;
v++;
}
}
count2 = 0;
v = add;
while (*v) {
count2++;
v++;
}
v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*));
v[count1 + count2] = NULL;
i = count2;
while (--i >= 0)
v[count1 + i] = (need_to_dup ? xstrdup(add[i]) : add[i]);
return v;
}
#if LEAK_HUNTING
static char **xx_add_strings_to_strings(int lineno, char **strings, char **add, int need_to_dup)
{
char **ptr = add_strings_to_strings(strings, add, need_to_dup);
fdprintf(2, "line %d: add_strings_to_strings %p\n", lineno, ptr);
return ptr;
}
#define add_strings_to_strings(strings, add, need_to_dup) \
xx_add_strings_to_strings(__LINE__, strings, add, need_to_dup)
#endif
/* Note: takes ownership of "add" ptr (it is not strdup'ed) */
static char **add_string_to_strings(char **strings, char *add)
{
char *v[2];
v[0] = add;
v[1] = NULL;
return add_strings_to_strings(strings, v, /*dup:*/ 0);
}
#if LEAK_HUNTING
static char **xx_add_string_to_strings(int lineno, char **strings, char *add)
{
char **ptr = add_string_to_strings(strings, add);
fdprintf(2, "line %d: add_string_to_strings %p\n", lineno, ptr);
return ptr;
}
#define add_string_to_strings(strings, add) \
xx_add_string_to_strings(__LINE__, strings, add)
#endif
static void free_strings(char **strings)
{
char **v;
if (!strings)
return;
v = strings;
while (*v) {
free(*v);
v++;
}
free(strings);
}
/* Helpers for setting new $n and restoring them back
*/
typedef struct save_arg_t {
char *sv_argv0;
char **sv_g_argv;
int sv_g_argc;
smallint sv_g_malloced;
} save_arg_t;
static void save_and_replace_G_args(save_arg_t *sv, char **argv)
{
int n;
sv->sv_argv0 = argv[0];
sv->sv_g_argv = G.global_argv;
sv->sv_g_argc = G.global_argc;
sv->sv_g_malloced = G.global_args_malloced;
argv[0] = G.global_argv[0]; /* retain $0 */
G.global_argv = argv;
G.global_args_malloced = 0;
n = 1;
while (*++argv)
n++;
G.global_argc = n;
}
static void restore_G_args(save_arg_t *sv, char **argv)
{
char **pp;
if (G.global_args_malloced) {
/* someone ran "set -- arg1 arg2 ...", undo */
pp = G.global_argv;
while (*++pp) /* note: does not free $0 */
free(*pp);
free(G.global_argv);
}
argv[0] = sv->sv_argv0;
G.global_argv = sv->sv_g_argv;
G.global_argc = sv->sv_g_argc;
G.global_args_malloced = sv->sv_g_malloced;
}
/* Basic theory of signal handling in shell
* ========================================
* This does not describe what hush does, rather, it is current understanding
* what it _should_ do. If it doesn't, it's a bug.
* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
*
* Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
* is finished or backgrounded. It is the same in interactive and
* non-interactive shells, and is the same regardless of whether
* a user trap handler is installed or a shell special one is in effect.
* ^C or ^Z from keyboard seems to execute "at once" because it usually
* backgrounds (i.e. stops) or kills all members of currently running
* pipe.
*
* Wait builtin in interruptible by signals for which user trap is set
* or by SIGINT in interactive shell.
*
* Trap handlers will execute even within trap handlers. (right?)
*
* User trap handlers are forgotten when subshell ("(cmd)") is entered,
* except for handlers set to '' (empty string).
*
* If job control is off, backgrounded commands ("cmd &")
* have SIGINT, SIGQUIT set to SIG_IGN.
*
* Commands which are run in command substitution ("`cmd`")
* have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
*
* Ordinary commands have signals set to SIG_IGN/DFL as inherited
* by the shell from its parent.
*
* Signals which differ from SIG_DFL action
* (note: child (i.e., [v]forked) shell is not an interactive shell):
*
* SIGQUIT: ignore
* SIGTERM (interactive): ignore
* SIGHUP (interactive):
* send SIGCONT to stopped jobs, send SIGHUP to all jobs and exit
* SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
* Note that ^Z is handled not by trapping SIGTSTP, but by seeing
* that all pipe members are stopped. Try this in bash:
* while :; do :; done - ^Z does not background it
* (while :; do :; done) - ^Z backgrounds it
* SIGINT (interactive): wait for last pipe, ignore the rest
* of the command line, show prompt. NB: ^C does not send SIGINT
* to interactive shell while shell is waiting for a pipe,
* since shell is bg'ed (is not in foreground process group).
* Example 1: this waits 5 sec, but does not execute ls:
* "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
* Example 2: this does not wait and does not execute ls:
* "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
* Example 3: this does not wait 5 sec, but executes ls:
* "sleep 5; ls -l" + press ^C
* Example 4: this does not wait and does not execute ls:
* "sleep 5 & wait; ls -l" + press ^C
*
* (What happens to signals which are IGN on shell start?)
* (What happens with signal mask on shell start?)
*
* Old implementation
* ==================
* We use in-kernel pending signal mask to determine which signals were sent.
* We block all signals which we don't want to take action immediately,
* i.e. we block all signals which need to have special handling as described
* above, and all signals which have traps set.
* After each pipe execution, we extract any pending signals via sigtimedwait()
* and act on them.
*
* unsigned special_sig_mask: a mask of such "special" signals
* sigset_t blocked_set: current blocked signal set
*
* "trap - SIGxxx":
* clear bit in blocked_set unless it is also in special_sig_mask
* "trap 'cmd' SIGxxx":
* set bit in blocked_set (even if 'cmd' is '')
* after [v]fork, if we plan to be a shell:
* unblock signals with special interactive handling
* (child shell is not interactive),
* unset all traps except '' (note: regardless of child shell's type - {}, (), etc)
* after [v]fork, if we plan to exec:
* POSIX says fork clears pending signal mask in child - no need to clear it.
* Restore blocked signal set to one inherited by shell just prior to exec.
*
* Note: as a result, we do not use signal handlers much. The only uses
* are to count SIGCHLDs
* and to restore tty pgrp on signal-induced exit.
*
* Note 2 (compat):
* Standard says "When a subshell is entered, traps that are not being ignored
* are set to the default actions". bash interprets it so that traps which
* are set to '' (ignore) are NOT reset to defaults. We do the same.
*
* Problem: the above approach makes it unwieldy to catch signals while
* we are in read builtin, of while we read commands from stdin:
* masked signals are not visible!
*
* New implementation
* ==================
* We record each signal we are interested in by installing signal handler
* for them - a bit like emulating kernel pending signal mask in userspace.
* We are interested in: signals which need to have special handling
* as described above, and all signals which have traps set.
* Signals are rocorded in pending_set.
* After each pipe execution, we extract any pending signals
* and act on them.
*
* unsigned special_sig_mask: a mask of shell-special signals.
* unsigned fatal_sig_mask: a mask of signals on which we restore tty pgrp.
* char *traps[sig] if trap for sig is set (even if it's '').
* sigset_t pending_set: set of sigs we received.
*
* "trap - SIGxxx":
* if sig is in special_sig_mask, set handler back to:
* record_pending_signo, or to IGN if it's a tty stop signal
* if sig is in fatal_sig_mask, set handler back to sigexit.
* else: set handler back to SIG_DFL
* "trap 'cmd' SIGxxx":
* set handler to record_pending_signo.
* "trap '' SIGxxx":
* set handler to SIG_IGN.
* after [v]fork, if we plan to be a shell:
* set signals with special interactive handling to SIG_DFL
* (because child shell is not interactive),
* unset all traps except '' (note: regardless of child shell's type - {}, (), etc)
* after [v]fork, if we plan to exec:
* POSIX says fork clears pending signal mask in child - no need to clear it.
*
* To make wait builtin interruptible, we handle SIGCHLD as special signal,
* otherwise (if we leave it SIG_DFL) sigsuspend in wait builtin will not wake up on it.
*
* Note (compat):
* Standard says "When a subshell is entered, traps that are not being ignored
* are set to the default actions". bash interprets it so that traps which
* are set to '' (ignore) are NOT reset to defaults. We do the same.
*/
enum {
SPECIAL_INTERACTIVE_SIGS = 0
| (1 << SIGTERM)
| (1 << SIGINT)
| (1 << SIGHUP)
,
SPECIAL_JOBSTOP_SIGS = 0
#if ENABLE_HUSH_JOB
| (1 << SIGTTIN)
| (1 << SIGTTOU)
| (1 << SIGTSTP)
#endif
,
};
static void record_pending_signo(int sig)
{
sigaddset(&G.pending_set, sig);
#if ENABLE_HUSH_FAST
if (sig == SIGCHLD) {
G.count_SIGCHLD++;
//bb_error_msg("[%d] SIGCHLD_handler: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
}
#endif
}
static sighandler_t install_sighandler(int sig, sighandler_t handler)
{
struct sigaction old_sa;
/* We could use signal() to install handlers... almost:
* except that we need to mask ALL signals while handlers run.
* I saw signal nesting in strace, race window isn't small.
* SA_RESTART is also needed, but in Linux, signal()
* sets SA_RESTART too.
*/
/* memset(&G.sa, 0, sizeof(G.sa)); - already done */
/* sigfillset(&G.sa.sa_mask); - already done */
/* G.sa.sa_flags = SA_RESTART; - already done */
G.sa.sa_handler = handler;
sigaction(sig, &G.sa, &old_sa);
return old_sa.sa_handler;
}
#if ENABLE_HUSH_JOB
/* After [v]fork, in child: do not restore tty pgrp on xfunc death */
# define disable_restore_tty_pgrp_on_exit() (die_sleep = 0)
/* After [v]fork, in parent: restore tty pgrp on xfunc death */
# define enable_restore_tty_pgrp_on_exit() (die_sleep = -1)
/* Restores tty foreground process group, and exits.
* May be called as signal handler for fatal signal
* (will resend signal to itself, producing correct exit state)
* or called directly with -EXITCODE.
* We also call it if xfunc is exiting. */
static void sigexit(int sig) NORETURN;
static void sigexit(int sig)
{
/* Careful: we can end up here after [v]fork. Do not restore
* tty pgrp then, only top-level shell process does that */
if (G_saved_tty_pgrp && getpid() == G.root_pid) {
/* Disable all signals: job control, SIGPIPE, etc.
* Mostly paranoid measure, to prevent infinite SIGTTOU.
*/
sigprocmask_allsigs(SIG_BLOCK);
tcsetpgrp(G_interactive_fd, G_saved_tty_pgrp);
}
/* Not a signal, just exit */
if (sig <= 0)
_exit(- sig);
kill_myself_with_sig(sig); /* does not return */
}
#else
# define disable_restore_tty_pgrp_on_exit() ((void)0)
# define enable_restore_tty_pgrp_on_exit() ((void)0)
#endif
static sighandler_t pick_sighandler(unsigned sig)
{
sighandler_t handler = SIG_DFL;
if (sig < sizeof(unsigned)*8) {
unsigned sigmask = (1 << sig);
#if ENABLE_HUSH_JOB
/* is sig fatal? */
if (G_fatal_sig_mask & sigmask)
handler = sigexit;
else
#endif
/* sig has special handling? */
if (G.special_sig_mask & sigmask) {
handler = record_pending_signo;
/* TTIN/TTOU/TSTP can't be set to record_pending_signo
* in order to ignore them: they will be raised
* in an endless loop when we try to do some
* terminal ioctls! We do have to _ignore_ these.
*/
if (SPECIAL_JOBSTOP_SIGS & sigmask)
handler = SIG_IGN;
}
}
return handler;
}
/* Restores tty foreground process group, and exits. */
static void hush_exit(int exitcode) NORETURN;
static void hush_exit(int exitcode)
{
fflush_all();
if (G.exiting <= 0 && G.traps && G.traps[0] && G.traps[0][0]) {
char *argv[3];
/* argv[0] is unused */
argv[1] = G.traps[0];
argv[2] = NULL;
G.exiting = 1; /* prevent EXIT trap recursion */
/* Note: G.traps[0] is not cleared!
* "trap" will still show it, if executed
* in the handler */
builtin_eval(argv);
}
#if ENABLE_FEATURE_CLEAN_UP
{
struct variable *cur_var;
if (G.cwd != bb_msg_unknown)
free((char*)G.cwd);
cur_var = G.top_var;
while (cur_var) {
struct variable *tmp = cur_var;
if (!cur_var->max_len)
free(cur_var->varstr);
cur_var = cur_var->next;
free(tmp);
}
}
#endif
#if ENABLE_HUSH_JOB
fflush_all();
sigexit(- (exitcode & 0xff));
#else
exit(exitcode);
#endif
}
//TODO: return a mask of ALL handled sigs?
static int check_and_run_traps(void)
{
int last_sig = 0;
while (1) {
int sig;
if (sigisemptyset(&G.pending_set))
break;
sig = 0;
do {
sig++;
if (sigismember(&G.pending_set, sig)) {
sigdelset(&G.pending_set, sig);
goto got_sig;
}
} while (sig < NSIG);
break;
got_sig:
if (G.traps && G.traps[sig]) {
if (G.traps[sig][0]) {
/* We have user-defined handler */
smalluint save_rcode;
char *argv[3];
/* argv[0] is unused */
argv[1] = G.traps[sig];
argv[2] = NULL;
save_rcode = G.last_exitcode;
builtin_eval(argv);
G.last_exitcode = save_rcode;
last_sig = sig;
} /* else: "" trap, ignoring signal */
continue;
}
/* not a trap: special action */
switch (sig) {
case SIGINT:
/* Builtin was ^C'ed, make it look prettier: */
bb_putchar('\n');
G.flag_SIGINT = 1;
last_sig = sig;
break;
#if ENABLE_HUSH_JOB
case SIGHUP: {
struct pipe *job;
/* bash is observed to signal whole process groups,
* not individual processes */
for (job = G.job_list; job; job = job->next) {
if (job->pgrp <= 0)
continue;
debug_printf_exec("HUPing pgrp %d\n", job->pgrp);
if (kill(- job->pgrp, SIGHUP) == 0)
kill(- job->pgrp, SIGCONT);
}
sigexit(SIGHUP);
}
#endif
#if ENABLE_HUSH_FAST
case SIGCHLD:
G.count_SIGCHLD++;
//bb_error_msg("[%d] check_and_run_traps: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
/* Note:
* We dont do 'last_sig = sig' here -> NOT returning this sig.
* This simplifies wait builtin a bit.
*/
break;
#endif
default: /* ignored: */
/* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
/* Note:
* We dont do 'last_sig = sig' here -> NOT returning this sig.
* Example: wait is not interrupted by TERM
* in interactive shell, because TERM is ignored.
*/
break;
}
}
return last_sig;
}
static const char *get_cwd(int force)
{
if (force || G.cwd == NULL) {
/* xrealloc_getcwd_or_warn(arg) calls free(arg),
* we must not try to free(bb_msg_unknown) */
if (G.cwd == bb_msg_unknown)
G.cwd = NULL;
G.cwd = xrealloc_getcwd_or_warn((char *)G.cwd);
if (!G.cwd)
G.cwd = bb_msg_unknown;
}
return G.cwd;
}
/*
* Shell and environment variable support
*/
static struct variable **get_ptr_to_local_var(const char *name, unsigned len)
{
struct variable **pp;
struct variable *cur;
pp = &G.top_var;
while ((cur = *pp) != NULL) {
if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=')
return pp;
pp = &cur->next;
}
return NULL;
}
static const char* FAST_FUNC get_local_var_value(const char *name)
{
struct variable **vpp;
unsigned len = strlen(name);
if (G.expanded_assignments) {
char **cpp = G.expanded_assignments;
while (*cpp) {
char *cp = *cpp;
if (strncmp(cp, name, len) == 0 && cp[len] == '=')
return cp + len + 1;
cpp++;
}
}
vpp = get_ptr_to_local_var(name, len);
if (vpp)
return (*vpp)->varstr + len + 1;
if (strcmp(name, "PPID") == 0)
return utoa(G.root_ppid);
// bash compat: UID? EUID?
#if ENABLE_HUSH_RANDOM_SUPPORT
if (strcmp(name, "RANDOM") == 0)
return utoa(next_random(&G.random_gen));
#endif
return NULL;
}
/* str holds "NAME=VAL" and is expected to be malloced.
* We take ownership of it.
* flg_export:
* 0: do not change export flag
* (if creating new variable, flag will be 0)
* 1: set export flag and putenv the variable
* -1: clear export flag and unsetenv the variable
* flg_read_only is set only when we handle -R var=val
*/
#if !BB_MMU && ENABLE_HUSH_LOCAL
/* all params are used */
#elif BB_MMU && ENABLE_HUSH_LOCAL
#define set_local_var(str, flg_export, local_lvl, flg_read_only) \
set_local_var(str, flg_export, local_lvl)
#elif BB_MMU && !ENABLE_HUSH_LOCAL
#define set_local_var(str, flg_export, local_lvl, flg_read_only) \
set_local_var(str, flg_export)
#elif !BB_MMU && !ENABLE_HUSH_LOCAL
#define set_local_var(str, flg_export, local_lvl, flg_read_only) \
set_local_var(str, flg_export, flg_read_only)
#endif
static int set_local_var(char *str, int flg_export, int local_lvl, int flg_read_only)
{
struct variable **var_pp;
struct variable *cur;
char *eq_sign;
int name_len;
eq_sign = strchr(str, '=');
if (!eq_sign) { /* not expected to ever happen? */
free(str);
return -1;
}
name_len = eq_sign - str + 1; /* including '=' */
var_pp = &G.top_var;
while ((cur = *var_pp) != NULL) {
if (strncmp(cur->varstr, str, name_len) != 0) {
var_pp = &cur->next;
continue;
}
/* We found an existing var with this name */
if (cur->flg_read_only) {
#if !BB_MMU
if (!flg_read_only)
#endif
bb_error_msg("%s: readonly variable", str);
free(str);
return -1;
}
if (flg_export == -1) { // "&& cur->flg_export" ?
debug_printf_env("%s: unsetenv '%s'\n", __func__, str);
*eq_sign = '\0';
unsetenv(str);
*eq_sign = '=';
}
#if ENABLE_HUSH_LOCAL
if (cur->func_nest_level < local_lvl) {
/* New variable is declared as local,
* and existing one is global, or local
* from enclosing function.
* Remove and save old one: */
*var_pp = cur->next;
cur->next = *G.shadowed_vars_pp;
*G.shadowed_vars_pp = cur;
/* bash 3.2.33(1) and exported vars:
* # export z=z
* # f() { local z=a; env | grep ^z; }
* # f
* z=a
* # env | grep ^z
* z=z
*/
if (cur->flg_export)
flg_export = 1;
break;
}
#endif
if (strcmp(cur->varstr + name_len, eq_sign + 1) == 0) {
free_and_exp:
free(str);
goto exp;
}
if (cur->max_len != 0) {
if (cur->max_len >= strlen(str)) {
/* This one is from startup env, reuse space */
strcpy(cur->varstr, str);
goto free_and_exp;
}
} else {
/* max_len == 0 signifies "malloced" var, which we can
* (and has to) free */
free(cur->varstr);
}
cur->max_len = 0;
goto set_str_and_exp;
}
/* Not found - create new variable struct */
cur = xzalloc(sizeof(*cur));
#if ENABLE_HUSH_LOCAL
cur->func_nest_level = local_lvl;
#endif
cur->next = *var_pp;
*var_pp = cur;
set_str_and_exp:
cur->varstr = str;
#if !BB_MMU
cur->flg_read_only = flg_read_only;
#endif
exp:
if (flg_export == 1)
cur->flg_export = 1;
if (name_len == 4 && cur->varstr[0] == 'P' && cur->varstr[1] == 'S')
cmdedit_update_prompt();
if (cur->flg_export) {
if (flg_export == -1) {
cur->flg_export = 0;
/* unsetenv was already done */
} else {
debug_printf_env("%s: putenv '%s'\n", __func__, cur->varstr);
return putenv(cur->varstr);
}
}
return 0;
}
/* Used at startup and after each cd */
static void set_pwd_var(int exp)
{
set_local_var(xasprintf("PWD=%s", get_cwd(/*force:*/ 1)),
/*exp:*/ exp, /*lvl:*/ 0, /*ro:*/ 0);
}
static int unset_local_var_len(const char *name, int name_len)
{
struct variable *cur;
struct variable **var_pp;
if (!name)
return EXIT_SUCCESS;
var_pp = &G.top_var;
while ((cur = *var_pp) != NULL) {
if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') {
if (cur->flg_read_only) {
bb_error_msg("%s: readonly variable", name);
return EXIT_FAILURE;
}
*var_pp = cur->next;
debug_printf_env("%s: unsetenv '%s'\n", __func__, cur->varstr);
bb_unsetenv(cur->varstr);
if (name_len == 3 && cur->varstr[0] == 'P' && cur->varstr[1] == 'S')
cmdedit_update_prompt();
if (!cur->max_len)
free(cur->varstr);
free(cur);
return EXIT_SUCCESS;
}
var_pp = &cur->next;
}
return EXIT_SUCCESS;
}
static int unset_local_var(const char *name)
{
return unset_local_var_len(name, strlen(name));
}
static void unset_vars(char **strings)
{
char **v;
if (!strings)
return;
v = strings;
while (*v) {
const char *eq = strchrnul(*v, '=');
unset_local_var_len(*v, (int)(eq - *v));
v++;
}
free(strings);
}
static void FAST_FUNC set_local_var_from_halves(const char *name, const char *val)
{
char *var = xasprintf("%s=%s", name, val);
set_local_var(var, /*flags:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
}
/*
* Helpers for "var1=val1 var2=val2 cmd" feature
*/
static void add_vars(struct variable *var)
{
struct variable *next;
while (var) {
next = var->next;
var->next = G.top_var;
G.top_var = var;
if (var->flg_export) {
debug_printf_env("%s: restoring exported '%s'\n", __func__, var->varstr);
putenv(var->varstr);
} else {
debug_printf_env("%s: restoring variable '%s'\n", __func__, var->varstr);
}
var = next;
}
}
static struct variable *set_vars_and_save_old(char **strings)
{
char **s;
struct variable *old = NULL;
if (!strings)
return old;
s = strings;
while (*s) {
struct variable *var_p;
struct variable **var_pp;
char *eq;
eq = strchr(*s, '=');
if (eq) {
var_pp = get_ptr_to_local_var(*s, eq - *s);
if (var_pp) {
/* Remove variable from global linked list */
var_p = *var_pp;
debug_printf_env("%s: removing '%s'\n", __func__, var_p->varstr);
*var_pp = var_p->next;
/* Add it to returned list */
var_p->next = old;
old = var_p;
}
set_local_var(*s, /*exp:*/ 1, /*lvl:*/ 0, /*ro:*/ 0);
}
s++;
}
return old;
}
/*
* in_str support
*/
static int FAST_FUNC static_get(struct in_str *i)
{
int ch = *i->p;
if (ch != '\0') {
i->p++;
i->last_char = ch;
return ch;
}
return EOF;
}
static int FAST_FUNC static_peek(struct in_str *i)
{
return *i->p;
}
#if ENABLE_HUSH_INTERACTIVE
static void cmdedit_update_prompt(void)
{
if (ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
G.PS1 = get_local_var_value("PS1");
if (G.PS1 == NULL)
G.PS1 = "\\w \\$ ";
G.PS2 = get_local_var_value("PS2");
} else {
G.PS1 = NULL;
}
if (G.PS2 == NULL)
G.PS2 = "> ";
}
static const char *setup_prompt_string(int promptmode)
{
const char *prompt_str;
debug_printf("setup_prompt_string %d ", promptmode);
if (!ENABLE_FEATURE_EDITING_FANCY_PROMPT) {
/* Set up the prompt */
if (promptmode == 0) { /* PS1 */
free((char*)G.PS1);
/* bash uses $PWD value, even if it is set by user.
* It uses current dir only if PWD is unset.
* We always use current dir. */
G.PS1 = xasprintf("%s %c ", get_cwd(0), (geteuid() != 0) ? '$' : '#');
prompt_str = G.PS1;
} else
prompt_str = G.PS2;
} else
prompt_str = (promptmode == 0) ? G.PS1 : G.PS2;
debug_printf("result '%s'\n", prompt_str);
return prompt_str;
}
static void get_user_input(struct in_str *i)
{
int r;
const char *prompt_str;
prompt_str = setup_prompt_string(i->promptmode);
# if ENABLE_FEATURE_EDITING
/* Enable command line editing only while a command line
* is actually being read */
do {
/* Unicode support should be activated even if LANG is set
* _during_ shell execution, not only if it was set when
* shell was started. Therefore, re-check LANG every time:
*/
reinit_unicode(get_local_var_value("LANG"));
G.flag_SIGINT = 0;
/* buglet: SIGINT will not make new prompt to appear _at once_,
* only after <Enter>. (^C will work) */
r = read_line_input(G.line_input_state, prompt_str, G.user_input_buf, CONFIG_FEATURE_EDITING_MAX_LEN-1, /*timeout*/ -1);
/* catch *SIGINT* etc (^C is handled by read_line_input) */
check_and_run_traps();
} while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */
i->eof_flag = (r < 0);
if (i->eof_flag) { /* EOF/error detected */
G.user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */
G.user_input_buf[1] = '\0';
}
# else
do {
G.flag_SIGINT = 0;
if (i->last_char == '\0' || i->last_char == '\n') {
/* Why check_and_run_traps here? Try this interactively:
* $ trap 'echo INT' INT; (sleep 2; kill -INT $$) &
* $ <[enter], repeatedly...>
* Without check_and_run_traps, handler never runs.
*/
check_and_run_traps();
fputs(prompt_str, stdout);
}
fflush_all();
G.user_input_buf[0] = r = fgetc(i->file);
/*G.user_input_buf[1] = '\0'; - already is and never changed */
} while (G.flag_SIGINT);
i->eof_flag = (r == EOF);
# endif
i->p = G.user_input_buf;
}
#endif /* INTERACTIVE */
/* This is the magic location that prints prompts
* and gets data back from the user */
static int FAST_FUNC file_get(struct in_str *i)
{
int ch;
/* If there is data waiting, eat it up */
if (i->p && *i->p) {
#if ENABLE_HUSH_INTERACTIVE
take_cached:
#endif
ch = *i->p++;
if (i->eof_flag && !*i->p)
ch = EOF;
/* note: ch is never NUL */
} else {
/* need to double check i->file because we might be doing something
* more complicated by now, like sourcing or substituting. */
#if ENABLE_HUSH_INTERACTIVE
if (G_interactive_fd && i->file == stdin) {
do {
get_user_input(i);
} while (!*i->p); /* need non-empty line */
i->promptmode = 1; /* PS2 */
goto take_cached;
}
#endif
do ch = fgetc(i->file); while (ch == '\0');
}
debug_printf("file_get: got '%c' %d\n", ch, ch);
i->last_char = ch;
return ch;
}
/* All callers guarantee this routine will never
* be used right after a newline, so prompting is not needed.
*/
static int FAST_FUNC file_peek(struct in_str *i)
{
int ch;
if (i->p && *i->p) {
if (i->eof_flag && !i->p[1])
return EOF;
return *i->p;
/* note: ch is never NUL */
}
do ch = fgetc(i->file); while (ch == '\0');
i->eof_flag = (ch == EOF);
i->peek_buf[0] = ch;
i->peek_buf[1] = '\0';
i->p = i->peek_buf;
debug_printf("file_peek: got '%c' %d\n", ch, ch);
return ch;
}
static void setup_file_in_str(struct in_str *i, FILE *f)
{
memset(i, 0, sizeof(*i));
i->peek = file_peek;
i->get = file_get;
/* i->promptmode = 0; - PS1 (memset did it) */
i->file = f;
/* i->p = NULL; */
}
static void setup_string_in_str(struct in_str *i, const char *s)
{
memset(i, 0, sizeof(*i));
i->peek = static_peek;
i->get = static_get;
/* i->promptmode = 0; - PS1 (memset did it) */
i->p = s;
/* i->eof_flag = 0; */
}
/*
* o_string support
*/
#define B_CHUNK (32 * sizeof(char*))
static void o_reset_to_empty_unquoted(o_string *o)
{
o->length = 0;
o->has_quoted_part = 0;
if (o->data)
o->data[0] = '\0';
}
static void o_free(o_string *o)
{
free(o->data);
memset(o, 0, sizeof(*o));
}
static ALWAYS_INLINE void o_free_unsafe(o_string *o)
{
free(o->data);
}
static void o_grow_by(o_string *o, int len)
{
if (o->length + len > o->maxlen) {
o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK);
o->data = xrealloc(o->data, 1 + o->maxlen);
}
}
static void o_addchr(o_string *o, int ch)
{
debug_printf("o_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o);
o_grow_by(o, 1);
o->data[o->length] = ch;
o->length++;
o->data[o->length] = '\0';
}
static void o_addblock(o_string *o, const char *str, int len)
{
o_grow_by(o, len);
memcpy(&o->data[o->length], str, len);
o->length += len;
o->data[o->length] = '\0';
}
static void o_addstr(o_string *o, const char *str)
{
o_addblock(o, str, strlen(str));
}
#if !BB_MMU
static void nommu_addchr(o_string *o, int ch)
{
if (o)
o_addchr(o, ch);
}
#else
# define nommu_addchr(o, str) ((void)0)
#endif
static void o_addstr_with_NUL(o_string *o, const char *str)
{
o_addblock(o, str, strlen(str) + 1);
}
/*
* HUSH_BRACE_EXPANSION code needs corresponding quoting on variable expansion side.
* Currently, "v='{q,w}'; echo $v" erroneously expands braces in $v.
* Apparently, on unquoted $v bash still does globbing
* ("v='*.txt'; echo $v" prints all .txt files),
* but NOT brace expansion! Thus, there should be TWO independent
* quoting mechanisms on $v expansion side: one protects
* $v from brace expansion, and other additionally protects "$v" against globbing.
* We have only second one.
*/
#if ENABLE_HUSH_BRACE_EXPANSION
# define MAYBE_BRACES "{}"
#else
# define MAYBE_BRACES ""
#endif
/* My analysis of quoting semantics tells me that state information
* is associated with a destination, not a source.
*/
static void o_addqchr(o_string *o, int ch)
{
int sz = 1;
char *found = strchr("*?[\\" MAYBE_BRACES, ch);
if (found)
sz++;
o_grow_by(o, sz);
if (found) {
o->data[o->length] = '\\';
o->length++;
}
o->data[o->length] = ch;
o->length++;
o->data[o->length] = '\0';
}
static void o_addQchr(o_string *o, int ch)
{
int sz = 1;
if ((o->o_expflags & EXP_FLAG_ESC_GLOB_CHARS)
&& strchr("*?[\\" MAYBE_BRACES, ch)
) {
sz++;
o->data[o->length] = '\\';
o->length++;
}
o_grow_by(o, sz);
o->data[o->length] = ch;
o->length++;
o->data[o->length] = '\0';
}
static void o_addqblock(o_string *o, const char *str, int len)
{
while (len) {
char ch;
int sz;
int ordinary_cnt = strcspn(str, "*?[\\" MAYBE_BRACES);
if (ordinary_cnt > len) /* paranoia */
ordinary_cnt = len;
o_addblock(o, str, ordinary_cnt);
if (ordinary_cnt == len)
return; /* NUL is already added by o_addblock */
str += ordinary_cnt;
len -= ordinary_cnt + 1; /* we are processing + 1 char below */
ch = *str++;
sz = 1;
if (ch) { /* it is necessarily one of "*?[\\" MAYBE_BRACES */
sz++;
o->data[o->length] = '\\';
o->length++;
}
o_grow_by(o, sz);
o->data[o->length] = ch;
o->length++;
}
o->data[o->length] = '\0';
}
static void o_addQblock(o_string *o, const char *str, int len)
{
if (!(o->o_expflags & EXP_FLAG_ESC_GLOB_CHARS)) {
o_addblock(o, str, len);
return;
}
o_addqblock(o, str, len);
}
static void o_addQstr(o_string *o, const char *str)
{
o_addQblock(o, str, strlen(str));
}
/* A special kind of o_string for $VAR and `cmd` expansion.
* It contains char* list[] at the beginning, which is grown in 16 element
* increments. Actual string data starts at the next multiple of 16 * (char*).
* list[i] contains an INDEX (int!) into this string data.
* It means that if list[] needs to grow, data needs to be moved higher up
* but list[i]'s need not be modified.
* NB: remembering how many list[i]'s you have there is crucial.
* o_finalize_list() operation post-processes this structure - calculates
* and stores actual char* ptrs in list[]. Oh, it NULL terminates it as well.
*/
#if DEBUG_EXPAND || DEBUG_GLOB
static void debug_print_list(const char *prefix, o_string *o, int n)
{
char **list = (char**)o->data;
int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
int i = 0;
indent();
fdprintf(2, "%s: list:%p n:%d string_start:%d length:%d maxlen:%d glob:%d quoted:%d escape:%d\n",
prefix, list, n, string_start, o->length, o->maxlen,
!!(o->o_expflags & EXP_FLAG_GLOB),
o->has_quoted_part,
!!(o->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
while (i < n) {
indent();
fdprintf(2, " list[%d]=%d '%s' %p\n", i, (int)(uintptr_t)list[i],
o->data + (int)(uintptr_t)list[i] + string_start,
o->data + (int)(uintptr_t)list[i] + string_start);
i++;
}
if (n) {
const char *p = o->data + (int)(uintptr_t)list[n - 1] + string_start;
indent();
fdprintf(2, " total_sz:%ld\n", (long)((p + strlen(p) + 1) - o->data));
}
}
#else
# define debug_print_list(prefix, o, n) ((void)0)
#endif
/* n = o_save_ptr_helper(str, n) "starts new string" by storing an index value
* in list[n] so that it points past last stored byte so far.
* It returns n+1. */
static int o_save_ptr_helper(o_string *o, int n)
{
char **list = (char**)o->data;
int string_start;
int string_len;
if (!o->has_empty_slot) {
string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
string_len = o->length - string_start;
if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
debug_printf_list("list[%d]=%d string_start=%d (growing)\n", n, string_len, string_start);
/* list[n] points to string_start, make space for 16 more pointers */
o->maxlen += 0x10 * sizeof(list[0]);
o->data = xrealloc(o->data, o->maxlen + 1);
list = (char**)o->data;
memmove(list + n + 0x10, list + n, string_len);
o->length += 0x10 * sizeof(list[0]);
} else {
debug_printf_list("list[%d]=%d string_start=%d\n",
n, string_len, string_start);
}
} else {
/* We have empty slot at list[n], reuse without growth */
string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
string_len = o->length - string_start;
debug_printf_list("list[%d]=%d string_start=%d (empty slot)\n",
n, string_len, string_start);
o->has_empty_slot = 0;
}
o->has_quoted_part = 0;
list[n] = (char*)(uintptr_t)string_len;
return n + 1;
}
/* "What was our last o_save_ptr'ed position (byte offset relative o->data)?" */
static int o_get_last_ptr(o_string *o, int n)
{
char **list = (char**)o->data;
int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
return ((int)(uintptr_t)list[n-1]) + string_start;
}
#if ENABLE_HUSH_BRACE_EXPANSION
/* There in a GNU extension, GLOB_BRACE, but it is not usable:
* first, it processes even {a} (no commas), second,
* I didn't manage to make it return strings when they don't match
* existing files. Need to re-implement it.
*/
/* Helper */
static int glob_needed(const char *s)
{
while (*s) {
if (*s == '\\') {
if (!s[1])
return 0;
s += 2;
continue;
}
if (*s == '*' || *s == '[' || *s == '?' || *s == '{')
return 1;
s++;
}
return 0;
}
/* Return pointer to next closing brace or to comma */
static const char *next_brace_sub(const char *cp)
{
unsigned depth = 0;
cp++;
while (*cp != '\0') {
if (*cp == '\\') {
if (*++cp == '\0')
break;
cp++;
continue;
}
if ((*cp == '}' && depth-- == 0) || (*cp == ',' && depth == 0))
break;
if (*cp++ == '{')
depth++;
}
return *cp != '\0' ? cp : NULL;
}
/* Recursive brace globber. Note: may garble pattern[]. */
static int glob_brace(char *pattern, o_string *o, int n)
{
char *new_pattern_buf;
const char *begin;
const char *next;
const char *rest;
const char *p;
size_t rest_len;
debug_printf_glob("glob_brace('%s')\n", pattern);
begin = pattern;
while (1) {
if (*begin == '\0')
goto simple_glob;
if (*begin == '{') {
/* Find the first sub-pattern and at the same time
* find the rest after the closing brace */
next = next_brace_sub(begin);
if (next == NULL) {
/* An illegal expression */
goto simple_glob;
}
if (*next == '}') {
/* "{abc}" with no commas - illegal
* brace expr, disregard and skip it */
begin = next + 1;
continue;
}
break;
}
if (*begin == '\\' && begin[1] != '\0')
begin++;
begin++;
}
debug_printf_glob("begin:%s\n", begin);
debug_printf_glob("next:%s\n", next);
/* Now find the end of the whole brace expression */
rest = next;
while (*rest != '}') {
rest = next_brace_sub(rest);
if (rest == NULL) {
/* An illegal expression */
goto simple_glob;
}
debug_printf_glob("rest:%s\n", rest);
}
rest_len = strlen(++rest) + 1;
/* We are sure the brace expression is well-formed */
/* Allocate working buffer large enough for our work */
new_pattern_buf = xmalloc(strlen(pattern));
/* We have a brace expression. BEGIN points to the opening {,
* NEXT points past the terminator of the first element, and REST
* points past the final }. We will accumulate result names from
* recursive runs for each brace alternative in the buffer using
* GLOB_APPEND. */
p = begin + 1;
while (1) {
/* Construct the new glob expression */
memcpy(
mempcpy(
mempcpy(new_pattern_buf,
/* We know the prefix for all sub-patterns */
pattern, begin - pattern),
p, next - p),
rest, rest_len);
/* Note: glob_brace() may garble new_pattern_buf[].
* That's why we re-copy prefix every time (1st memcpy above).
*/
n = glob_brace(new_pattern_buf, o, n);
if (*next == '}') {
/* We saw the last entry */
break;
}
p = next + 1;
next = next_brace_sub(next);
}
free(new_pattern_buf);
return n;
simple_glob:
{
int gr;
glob_t globdata;
memset(&globdata, 0, sizeof(globdata));
gr = glob(pattern, 0, NULL, &globdata);
debug_printf_glob("glob('%s'):%d\n", pattern, gr);
if (gr != 0) {
if (gr == GLOB_NOMATCH) {
globfree(&globdata);
/* NB: garbles parameter */
unbackslash(pattern);
o_addstr_with_NUL(o, pattern);
debug_printf_glob("glob pattern '%s' is literal\n", pattern);
return o_save_ptr_helper(o, n);
}
if (gr == GLOB_NOSPACE)
bb_error_msg_and_die(bb_msg_memory_exhausted);
/* GLOB_ABORTED? Only happens with GLOB_ERR flag,
* but we didn't specify it. Paranoia again. */
bb_error_msg_and_die("glob error %d on '%s'", gr, pattern);
}
if (globdata.gl_pathv && globdata.gl_pathv[0]) {
char **argv = globdata.gl_pathv;
while (1) {
o_addstr_with_NUL(o, *argv);
n = o_save_ptr_helper(o, n);
argv++;
if (!*argv)
break;
}
}
globfree(&globdata);
}
return n;
}
/* Performs globbing on last list[],
* saving each result as a new list[].
*/
static int perform_glob(o_string *o, int n)
{
char *pattern, *copy;
debug_printf_glob("start perform_glob: n:%d o->data:%p\n", n, o->data);
if (!o->data)
return o_save_ptr_helper(o, n);
pattern = o->data + o_get_last_ptr(o, n);
debug_printf_glob("glob pattern '%s'\n", pattern);
if (!glob_needed(pattern)) {
/* unbackslash last string in o in place, fix length */
o->length = unbackslash(pattern) - o->data;
debug_printf_glob("glob pattern '%s' is literal\n", pattern);
return o_save_ptr_helper(o, n);
}
copy = xstrdup(pattern);
/* "forget" pattern in o */
o->length = pattern - o->data;
n = glob_brace(copy, o, n);
free(copy);
if (DEBUG_GLOB)
debug_print_list("perform_glob returning", o, n);
return n;
}
#else /* !HUSH_BRACE_EXPANSION */
/* Helper */
static int glob_needed(const char *s)
{
while (*s) {
if (*s == '\\') {
if (!s[1])
return 0;
s += 2;
continue;
}
if (*s == '*' || *s == '[' || *s == '?')
return 1;
s++;
}
return 0;
}
/* Performs globbing on last list[],
* saving each result as a new list[].
*/
static int perform_glob(o_string *o, int n)
{
glob_t globdata;
int gr;
char *pattern;
debug_printf_glob("start perform_glob: n:%d o->data:%p\n", n, o->data);
if (!o->data)
return o_save_ptr_helper(o, n);
pattern = o->data + o_get_last_ptr(o, n);
debug_printf_glob("glob pattern '%s'\n", pattern);
if (!glob_needed(pattern)) {
literal:
/* unbackslash last string in o in place, fix length */
o->length = unbackslash(pattern) - o->data;
debug_printf_glob("glob pattern '%s' is literal\n", pattern);
return o_save_ptr_helper(o, n);
}
memset(&globdata, 0, sizeof(globdata));
/* Can't use GLOB_NOCHECK: it does not unescape the string.
* If we glob "*.\*" and don't find anything, we need
* to fall back to using literal "*.*", but GLOB_NOCHECK
* will return "*.\*"!
*/
gr = glob(pattern, 0, NULL, &globdata);
debug_printf_glob("glob('%s'):%d\n", pattern, gr);
if (gr != 0) {
if (gr == GLOB_NOMATCH) {
globfree(&globdata);
goto literal;
}
if (gr == GLOB_NOSPACE)
bb_error_msg_and_die(bb_msg_memory_exhausted);
/* GLOB_ABORTED? Only happens with GLOB_ERR flag,
* but we didn't specify it. Paranoia again. */
bb_error_msg_and_die("glob error %d on '%s'", gr, pattern);
}
if (globdata.gl_pathv && globdata.gl_pathv[0]) {
char **argv = globdata.gl_pathv;
/* "forget" pattern in o */
o->length = pattern - o->data;
while (1) {
o_addstr_with_NUL(o, *argv);
n = o_save_ptr_helper(o, n);
argv++;
if (!*argv)
break;
}
}
globfree(&globdata);
if (DEBUG_GLOB)
debug_print_list("perform_glob returning", o, n);
return n;
}
#endif /* !HUSH_BRACE_EXPANSION */
/* If o->o_expflags & EXP_FLAG_GLOB, glob the string so far remembered.
* Otherwise, just finish current list[] and start new */
static int o_save_ptr(o_string *o, int n)
{
if (o->o_expflags & EXP_FLAG_GLOB) {
/* If o->has_empty_slot, list[n] was already globbed
* (if it was requested back then when it was filled)
* so don't do that again! */
if (!o->has_empty_slot)
return perform_glob(o, n); /* o_save_ptr_helper is inside */
}
return o_save_ptr_helper(o, n);
}
/* "Please convert list[n] to real char* ptrs, and NULL terminate it." */
static char **o_finalize_list(o_string *o, int n)
{
char **list;
int string_start;
n = o_save_ptr(o, n); /* force growth for list[n] if necessary */
if (DEBUG_EXPAND)
debug_print_list("finalized", o, n);
debug_printf_expand("finalized n:%d\n", n);
list = (char**)o->data;
string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
list[--n] = NULL;
while (n) {
n--;
list[n] = o->data + (int)(uintptr_t)list[n] + string_start;
}
return list;
}
static void free_pipe_list(struct pipe *pi);
/* Returns pi->next - next pipe in the list */
static struct pipe *free_pipe(struct pipe *pi)
{
struct pipe *next;
int i;
debug_printf_clean("free_pipe (pid %d)\n", getpid());
for (i = 0; i < pi->num_cmds; i++) {
struct command *command;
struct redir_struct *r, *rnext;
command = &pi->cmds[i];
debug_printf_clean(" command %d:\n", i);
if (command->argv) {
if (DEBUG_CLEAN) {
int a;
char **p;
for (a = 0, p = command->argv; *p; a++, p++) {
debug_printf_clean(" argv[%d] = %s\n", a, *p);
}
}
free_strings(command->argv);
//command->argv = NULL;
}
/* not "else if": on syntax error, we may have both! */
if (command->group) {
debug_printf_clean(" begin group (cmd_type:%d)\n",
command->cmd_type);
free_pipe_list(command->group);
debug_printf_clean(" end group\n");
//command->group = NULL;
}
/* else is crucial here.
* If group != NULL, child_func is meaningless */
#if ENABLE_HUSH_FUNCTIONS
else if (command->child_func) {
debug_printf_exec("cmd %p releases child func at %p\n", command, command->child_func);
command->child_func->parent_cmd = NULL;
}
#endif
#if !BB_MMU
free(command->group_as_string);
//command->group_as_string = NULL;
#endif
for (r = command->redirects; r; r = rnext) {
debug_printf_clean(" redirect %d%s",
r->rd_fd, redir_table[r->rd_type].descrip);
/* guard against the case >$FOO, where foo is unset or blank */
if (r->rd_filename) {
debug_printf_clean(" fname:'%s'\n", r->rd_filename);
free(r->rd_filename);
//r->rd_filename = NULL;
}
debug_printf_clean(" rd_dup:%d\n", r->rd_dup);
rnext = r->next;
free(r);
}
//command->redirects = NULL;
}
free(pi->cmds); /* children are an array, they get freed all at once */
//pi->cmds = NULL;
#if ENABLE_HUSH_JOB
free(pi->cmdtext);
//pi->cmdtext = NULL;
#endif
next = pi->next;
free(pi);
return next;
}
static void free_pipe_list(struct pipe *pi)
{
while (pi) {
#if HAS_KEYWORDS
debug_printf_clean("pipe reserved word %d\n", pi->res_word);
#endif
debug_printf_clean("pipe followup code %d\n", pi->followup);
pi = free_pipe(pi);
}
}
/*** Parsing routines ***/
#ifndef debug_print_tree
static void debug_print_tree(struct pipe *pi, int lvl)
{
static const char *const PIPE[] = {
[PIPE_SEQ] = "SEQ",
[PIPE_AND] = "AND",
[PIPE_OR ] = "OR" ,
[PIPE_BG ] = "BG" ,
};
static const char *RES[] = {
[RES_NONE ] = "NONE" ,
# if ENABLE_HUSH_IF
[RES_IF ] = "IF" ,
[RES_THEN ] = "THEN" ,
[RES_ELIF ] = "ELIF" ,
[RES_ELSE ] = "ELSE" ,
[RES_FI ] = "FI" ,
# endif
# if ENABLE_HUSH_LOOPS
[RES_FOR ] = "FOR" ,
[RES_WHILE] = "WHILE",
[RES_UNTIL] = "UNTIL",
[RES_DO ] = "DO" ,
[RES_DONE ] = "DONE" ,
# endif
# if ENABLE_HUSH_LOOPS || ENABLE_HUSH_CASE
[RES_IN ] = "IN" ,
# endif
# if ENABLE_HUSH_CASE
[RES_CASE ] = "CASE" ,
[RES_CASE_IN ] = "CASE_IN" ,
[RES_MATCH] = "MATCH",
[RES_CASE_BODY] = "CASE_BODY",
[RES_ESAC ] = "ESAC" ,
# endif
[RES_XXXX ] = "XXXX" ,
[RES_SNTX ] = "SNTX" ,
};
static const char *const CMDTYPE[] = {
"{}",
"()",
"[noglob]",
# if ENABLE_HUSH_FUNCTIONS
"func()",
# endif
};
int pin, prn;
pin = 0;
while (pi) {
fdprintf(2, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "",
pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]);
prn = 0;
while (prn < pi->num_cmds) {
struct command *command = &pi->cmds[prn];
char **argv = command->argv;
fdprintf(2, "%*s cmd %d assignment_cnt:%d",
lvl*2, "", prn,
command->assignment_cnt);
if (command->group) {
fdprintf(2, " group %s: (argv=%p)%s%s\n",
CMDTYPE[command->cmd_type],
argv
# if !BB_MMU
, " group_as_string:", command->group_as_string
# else
, "", ""
# endif
);
debug_print_tree(command->group, lvl+1);
prn++;
continue;
}
if (argv) while (*argv) {
fdprintf(2, " '%s'", *argv);
argv++;
}
fdprintf(2, "\n");
prn++;
}
pi = pi->next;
pin++;
}
}
#endif /* debug_print_tree */
static struct pipe *new_pipe(void)
{
struct pipe *pi;
pi = xzalloc(sizeof(struct pipe));
/*pi->followup = 0; - deliberately invalid value */
/*pi->res_word = RES_NONE; - RES_NONE is 0 anyway */
return pi;
}
/* Command (member of a pipe) is complete, or we start a new pipe
* if ctx->command is NULL.
* No errors possible here.
*/
static int done_command(struct parse_context *ctx)
{
/* The command is really already in the pipe structure, so
* advance the pipe counter and make a new, null command. */
struct pipe *pi = ctx->pipe;
struct command *command = ctx->command;
if (command) {
if (IS_NULL_CMD(command)) {
debug_printf_parse("done_command: skipping null cmd, num_cmds=%d\n", pi->num_cmds);
goto clear_and_ret;
}
pi->num_cmds++;
debug_printf_parse("done_command: ++num_cmds=%d\n", pi->num_cmds);
//debug_print_tree(ctx->list_head, 20);
} else {
debug_printf_parse("done_command: initializing, num_cmds=%d\n", pi->num_cmds);
}
/* Only real trickiness here is that the uncommitted
* command structure is not counted in pi->num_cmds. */
pi->cmds = xrealloc(pi->cmds, sizeof(*pi->cmds) * (pi->num_cmds+1));
ctx->command = command = &pi->cmds[pi->num_cmds];
clear_and_ret:
memset(command, 0, sizeof(*command));
return pi->num_cmds; /* used only for 0/nonzero check */
}
static void done_pipe(struct parse_context *ctx, pipe_style type)
{
int not_null;
debug_printf_parse("done_pipe entered, followup %d\n", type);
/* Close previous command */
not_null = done_command(ctx);
ctx->pipe->followup = type;
#if HAS_KEYWORDS
ctx->pipe->pi_inverted = ctx->ctx_inverted;
ctx->ctx_inverted = 0;
ctx->pipe->res_word = ctx->ctx_res_w;
#endif
/* Without this check, even just <enter> on command line generates
* tree of three NOPs (!). Which is harmless but annoying.
* IOW: it is safe to do it unconditionally. */
if (not_null
#if ENABLE_HUSH_IF
|| ctx->ctx_res_w == RES_FI
#endif
#if ENABLE_HUSH_LOOPS
|| ctx->ctx_res_w == RES_DONE
|| ctx->ctx_res_w == RES_FOR
|| ctx->ctx_res_w == RES_IN
#endif
#if ENABLE_HUSH_CASE
|| ctx->ctx_res_w == RES_ESAC
#endif
) {
struct pipe *new_p;
debug_printf_parse("done_pipe: adding new pipe: "
"not_null:%d ctx->ctx_res_w:%d\n",
not_null, ctx->ctx_res_w);
new_p = new_pipe();
ctx->pipe->next = new_p;
ctx->pipe = new_p;
/* RES_THEN, RES_DO etc are "sticky" -
* they remain set for pipes inside if/while.
* This is used to control execution.
* RES_FOR and RES_IN are NOT sticky (needed to support
* cases where variable or value happens to match a keyword):
*/
#if ENABLE_HUSH_LOOPS
if (ctx->ctx_res_w == RES_FOR
|| ctx->ctx_res_w == RES_IN)
ctx->ctx_res_w = RES_NONE;
#endif
#if ENABLE_HUSH_CASE
if (ctx->ctx_res_w == RES_MATCH)
ctx->ctx_res_w = RES_CASE_BODY;
if (ctx->ctx_res_w == RES_CASE)
ctx->ctx_res_w = RES_CASE_IN;
#endif
ctx->command = NULL; /* trick done_command below */
/* Create the memory for command, roughly:
* ctx->pipe->cmds = new struct command;
* ctx->command = &ctx->pipe->cmds[0];
*/
done_command(ctx);
//debug_print_tree(ctx->list_head, 10);
}
debug_printf_parse("done_pipe return\n");
}
static void initialize_context(struct parse_context *ctx)
{
memset(ctx, 0, sizeof(*ctx));
ctx->pipe = ctx->list_head = new_pipe();
/* Create the memory for command, roughly:
* ctx->pipe->cmds = new struct command;
* ctx->command = &ctx->pipe->cmds[0];
*/
done_command(ctx);
}
/* If a reserved word is found and processed, parse context is modified
* and 1 is returned.
*/
#if HAS_KEYWORDS
struct reserved_combo {
char literal[6];
unsigned char res;
unsigned char assignment_flag;
int flag;
};
enum {
FLAG_END = (1 << RES_NONE ),
# if ENABLE_HUSH_IF
FLAG_IF = (1 << RES_IF ),
FLAG_THEN = (1 << RES_THEN ),
FLAG_ELIF = (1 << RES_ELIF ),
FLAG_ELSE = (1 << RES_ELSE ),
FLAG_FI = (1 << RES_FI ),
# endif
# if ENABLE_HUSH_LOOPS
FLAG_FOR = (1 << RES_FOR ),
FLAG_WHILE = (1 << RES_WHILE),
FLAG_UNTIL = (1 << RES_UNTIL),
FLAG_DO = (1 << RES_DO ),
FLAG_DONE = (1 << RES_DONE ),
FLAG_IN = (1 << RES_IN ),
# endif
# if ENABLE_HUSH_CASE
FLAG_MATCH = (1 << RES_MATCH),
FLAG_ESAC = (1 << RES_ESAC ),
# endif
FLAG_START = (1 << RES_XXXX ),
};
static const struct reserved_combo* match_reserved_word(o_string *word)
{
/* Mostly a list of accepted follow-up reserved words.
* FLAG_END means we are done with the sequence, and are ready
* to turn the compound list into a command.
* FLAG_START means the word must start a new compound list.
*/
static const struct reserved_combo reserved_list[] = {
# if ENABLE_HUSH_IF
{ "!", RES_NONE, NOT_ASSIGNMENT , 0 },
{ "if", RES_IF, MAYBE_ASSIGNMENT, FLAG_THEN | FLAG_START },
{ "then", RES_THEN, MAYBE_ASSIGNMENT, FLAG_ELIF | FLAG_ELSE | FLAG_FI },
{ "elif", RES_ELIF, MAYBE_ASSIGNMENT, FLAG_THEN },
{ "else", RES_ELSE, MAYBE_ASSIGNMENT, FLAG_FI },
{ "fi", RES_FI, NOT_ASSIGNMENT , FLAG_END },
# endif
# if ENABLE_HUSH_LOOPS
{ "for", RES_FOR, NOT_ASSIGNMENT , FLAG_IN | FLAG_DO | FLAG_START },
{ "while", RES_WHILE, MAYBE_ASSIGNMENT, FLAG_DO | FLAG_START },
{ "until", RES_UNTIL, MAYBE_ASSIGNMENT, FLAG_DO | FLAG_START },
{ "in", RES_IN, NOT_ASSIGNMENT , FLAG_DO },
{ "do", RES_DO, MAYBE_ASSIGNMENT, FLAG_DONE },
{ "done", RES_DONE, NOT_ASSIGNMENT , FLAG_END },
# endif
# if ENABLE_HUSH_CASE
{ "case", RES_CASE, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_START },
{ "esac", RES_ESAC, NOT_ASSIGNMENT , FLAG_END },
# endif
};
const struct reserved_combo *r;
for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) {
if (strcmp(word->data, r->literal) == 0)
return r;
}
return NULL;
}
/* Return 0: not a keyword, 1: keyword
*/
static int reserved_word(o_string *word, struct parse_context *ctx)
{
# if ENABLE_HUSH_CASE
static const struct reserved_combo reserved_match = {
"", RES_MATCH, NOT_ASSIGNMENT , FLAG_MATCH | FLAG_ESAC
};
# endif
const struct reserved_combo *r;
if (word->has_quoted_part)
return 0;
r = match_reserved_word(word);
if (!r)
return 0;
debug_printf("found reserved word %s, res %d\n", r->literal, r->res);
# if ENABLE_HUSH_CASE
if (r->res == RES_IN && ctx->ctx_res_w == RES_CASE_IN) {
/* "case word IN ..." - IN part starts first MATCH part */
r = &reserved_match;
} else
# endif
if (r->flag == 0) { /* '!' */
if (ctx->ctx_inverted) { /* bash doesn't accept '! ! true' */
syntax_error("! ! command");
ctx->ctx_res_w = RES_SNTX;
}
ctx->ctx_inverted = 1;
return 1;
}
if (r->flag & FLAG_START) {
struct parse_context *old;
old = xmalloc(sizeof(*old));
debug_printf_parse("push stack %p\n", old);
*old = *ctx; /* physical copy */
initialize_context(ctx);
ctx->stack = old;
} else if (/*ctx->ctx_res_w == RES_NONE ||*/ !(ctx->old_flag & (1 << r->res))) {
syntax_error_at(word->data);
ctx->ctx_res_w = RES_SNTX;
return 1;
} else {
/* "{...} fi" is ok. "{...} if" is not
* Example:
* if { echo foo; } then { echo bar; } fi */
if (ctx->command->group)
done_pipe(ctx, PIPE_SEQ);
}
ctx->ctx_res_w = r->res;
ctx->old_flag = r->flag;
word->o_assignment = r->assignment_flag;
debug_printf_parse("word->o_assignment='%s'\n", assignment_flag[word->o_assignment]);
if (ctx->old_flag & FLAG_END) {
struct parse_context *old;
done_pipe(ctx, PIPE_SEQ);
debug_printf_parse("pop stack %p\n", ctx->stack);
old = ctx->stack;
old->command->group = ctx->list_head;
old->command->cmd_type = CMD_NORMAL;
# if !BB_MMU
o_addstr(&old->as_string, ctx->as_string.data);
o_free_unsafe(&ctx->as_string);
old->command->group_as_string = xstrdup(old->as_string.data);
debug_printf_parse("pop, remembering as:'%s'\n",
old->command->group_as_string);
# endif
*ctx = *old; /* physical copy */
free(old);
}
return 1;
}
#endif /* HAS_KEYWORDS */
/* Word is complete, look at it and update parsing context.
* Normal return is 0. Syntax errors return 1.
* Note: on return, word is reset, but not o_free'd!
*/
static int done_word(o_string *word, struct parse_context *ctx)
{
struct command *command = ctx->command;
debug_printf_parse("done_word entered: '%s' %p\n", word->data, command);
if (word->length == 0 && !word->has_quoted_part) {
debug_printf_parse("done_word return 0: true null, ignored\n");
return 0;
}
if (ctx->pending_redirect) {
/* We do not glob in e.g. >*.tmp case. bash seems to glob here
* only if run as "bash", not "sh" */
/* http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html
* "2.7 Redirection
* ...the word that follows the redirection operator
* shall be subjected to tilde expansion, parameter expansion,
* command substitution, arithmetic expansion, and quote
* removal. Pathname expansion shall not be performed
* on the word by a non-interactive shell; an interactive
* shell may perform it, but shall do so only when
* the expansion would result in one word."
*/
ctx->pending_redirect->rd_filename = xstrdup(word->data);
/* Cater for >\file case:
* >\a creates file a; >\\a, >"\a", >"\\a" create file \a
* Same with heredocs:
* for <<\H delim is H; <<\\H, <<"\H", <<"\\H" - \H
*/
if (ctx->pending_redirect->rd_type == REDIRECT_HEREDOC) {
unbackslash(ctx->pending_redirect->rd_filename);
/* Is it <<"HEREDOC"? */
if (word->has_quoted_part) {
ctx->pending_redirect->rd_dup |= HEREDOC_QUOTED;
}
}
debug_printf_parse("word stored in rd_filename: '%s'\n", word->data);
ctx->pending_redirect = NULL;
} else {
#if HAS_KEYWORDS
# if ENABLE_HUSH_CASE
if (ctx->ctx_dsemicolon
&& strcmp(word->data, "esac") != 0 /* not "... pattern) cmd;; esac" */
) {
/* already done when ctx_dsemicolon was set to 1: */
/* ctx->ctx_res_w = RES_MATCH; */
ctx->ctx_dsemicolon = 0;
} else
# endif
if (!command->argv /* if it's the first word... */
# if ENABLE_HUSH_LOOPS
&& ctx->ctx_res_w != RES_FOR /* ...not after FOR or IN */
&& ctx->ctx_res_w != RES_IN
# endif
# if ENABLE_HUSH_CASE
&& ctx->ctx_res_w != RES_CASE
# endif
) {
int reserved = reserved_word(word, ctx);
debug_printf_parse("checking for reserved-ness: %d\n", reserved);
if (reserved) {
o_reset_to_empty_unquoted(word);
debug_printf_parse("done_word return %d\n",
(ctx->ctx_res_w == RES_SNTX));
return (ctx->ctx_res_w == RES_SNTX);
}
# if ENABLE_HUSH_BASH_COMPAT
if (strcmp(word->data, "[[") == 0) {
command->cmd_type = CMD_SINGLEWORD_NOGLOB;
}
/* fall through */
# endif
}
#endif
if (command->group) {
/* "{ echo foo; } echo bar" - bad */
syntax_error_at(word->data);
debug_printf_parse("done_word return 1: syntax error, "
"groups and arglists don't mix\n");
return 1;
}
/* If this word wasn't an assignment, next ones definitely
* can't be assignments. Even if they look like ones. */
if (word->o_assignment != DEFINITELY_ASSIGNMENT
&& word->o_assignment != WORD_IS_KEYWORD
) {
word->o_assignment = NOT_ASSIGNMENT;
} else {
if (word->o_assignment == DEFINITELY_ASSIGNMENT) {
command->assignment_cnt++;
debug_printf_parse("++assignment_cnt=%d\n", command->assignment_cnt);
}
debug_printf_parse("word->o_assignment was:'%s'\n", assignment_flag[word->o_assignment]);
word->o_assignment = MAYBE_ASSIGNMENT;
}
debug_printf_parse("word->o_assignment='%s'\n", assignment_flag[word->o_assignment]);
if (word->has_quoted_part
/* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
&& (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
/* (otherwise it's known to be not empty and is already safe) */
) {
/* exclude "$@" - it can expand to no word despite "" */
char *p = word->data;
while (p[0] == SPECIAL_VAR_SYMBOL
&& (p[1] & 0x7f) == '@'
&& p[2] == SPECIAL_VAR_SYMBOL
) {
p += 3;
}
}
command->argv = add_string_to_strings(command->argv, xstrdup(word->data));
debug_print_strings("word appended to argv", command->argv);
}
#if ENABLE_HUSH_LOOPS
if (ctx->ctx_res_w == RES_FOR) {
if (word->has_quoted_part
|| !is_well_formed_var_name(command->argv[0], '\0')
) {
/* bash says just "not a valid identifier" */
syntax_error("not a valid identifier in for");
return 1;
}
/* Force FOR to have just one word (variable name) */
/* NB: basically, this makes hush see "for v in ..."
* syntax as if it is "for v; in ...". FOR and IN become
* two pipe structs in parse tree. */
done_pipe(ctx, PIPE_SEQ);
}
#endif
#if ENABLE_HUSH_CASE
/* Force CASE to have just one word */
if (ctx->ctx_res_w == RES_CASE) {
done_pipe(ctx, PIPE_SEQ);
}
#endif
o_reset_to_empty_unquoted(word);
debug_printf_parse("done_word return 0\n");
return 0;
}
/* Peek ahead in the input to find out if we have a "&n" construct,
* as in "2>&1", that represents duplicating a file descriptor.
* Return:
* REDIRFD_CLOSE if >&- "close fd" construct is seen,
* REDIRFD_SYNTAX_ERR if syntax error,
* REDIRFD_TO_FILE if no & was seen,
* or the number found.
*/
#if BB_MMU
#define parse_redir_right_fd(as_string, input) \
parse_redir_right_fd(input)
#endif
static int parse_redir_right_fd(o_string *as_string, struct in_str *input)
{
int ch, d, ok;
ch = i_peek(input);
if (ch != '&')
return REDIRFD_TO_FILE;
ch = i_getch(input); /* get the & */
nommu_addchr(as_string, ch);
ch = i_peek(input);
if (ch == '-') {
ch = i_getch(input);
nommu_addchr(as_string, ch);
return REDIRFD_CLOSE;
}
d = 0;
ok = 0;
while (ch != EOF && isdigit(ch)) {
d = d*10 + (ch-'0');
ok = 1;
ch = i_getch(input);
nommu_addchr(as_string, ch);
ch = i_peek(input);
}
if (ok) return d;
//TODO: this is the place to catch ">&file" bashism (redirect both fd 1 and 2)
bb_error_msg("ambiguous redirect");
return REDIRFD_SYNTAX_ERR;
}
/* Return code is 0 normal, 1 if a syntax error is detected
*/
static int parse_redirect(struct parse_context *ctx,
int fd,
redir_type style,
struct in_str *input)
{
struct command *command = ctx->command;
struct redir_struct *redir;
struct redir_struct **redirp;
int dup_num;
dup_num = REDIRFD_TO_FILE;
if (style != REDIRECT_HEREDOC) {
/* Check for a '>&1' type redirect */
dup_num = parse_redir_right_fd(&ctx->as_string, input);
if (dup_num == REDIRFD_SYNTAX_ERR)
return 1;
} else {
int ch = i_peek(input);
dup_num = (ch == '-'); /* HEREDOC_SKIPTABS bit is 1 */
if (dup_num) { /* <<-... */
ch = i_getch(input);
nommu_addchr(&ctx->as_string, ch);
ch = i_peek(input);
}
}
if (style == REDIRECT_OVERWRITE && dup_num == REDIRFD_TO_FILE) {
int ch = i_peek(input);
if (ch == '|') {
/* >|FILE redirect ("clobbering" >).
* Since we do not support "set -o noclobber" yet,
* >| and > are the same for now. Just eat |.
*/
ch = i_getch(input);
nommu_addchr(&ctx->as_string, ch);
}
}
/* Create a new redir_struct and append it to the linked list */
redirp = &command->redirects;
while ((redir = *redirp) != NULL) {
redirp = &(redir->next);
}
*redirp = redir = xzalloc(sizeof(*redir));
/* redir->next = NULL; */
/* redir->rd_filename = NULL; */
redir->rd_type = style;
redir->rd_fd = (fd == -1) ? redir_table[style].default_fd : fd;
debug_printf_parse("redirect type %d %s\n", redir->rd_fd,
redir_table[style].descrip);
redir->rd_dup = dup_num;
if (style != REDIRECT_HEREDOC && dup_num != REDIRFD_TO_FILE) {
/* Erik had a check here that the file descriptor in question
* is legit; I postpone that to "run time"
* A "-" representation of "close me" shows up as a -3 here */
debug_printf_parse("duplicating redirect '%d>&%d'\n",
redir->rd_fd, redir->rd_dup);
} else {
/* Set ctx->pending_redirect, so we know what to do at the
* end of the next parsed word. */
ctx->pending_redirect = redir;
}
return 0;
}
/* If a redirect is immediately preceded by a number, that number is
* supposed to tell which file descriptor to redirect. This routine
* looks for such preceding numbers. In an ideal world this routine
* needs to handle all the following classes of redirects...
* echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo
* echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo
* echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo
* echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo
*
* http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html
* "2.7 Redirection
* ... If n is quoted, the number shall not be recognized as part of
* the redirection expression. For example:
* echo \2>a
* writes the character 2 into file a"
* We are getting it right by setting ->has_quoted_part on any \<char>
*
* A -1 return means no valid number was found,
* the caller should use the appropriate default for this redirection.
*/
static int redirect_opt_num(o_string *o)
{
int num;
if (o->data == NULL)
return -1;
num = bb_strtou(o->data, NULL, 10);
if (errno || num < 0)
return -1;
o_reset_to_empty_unquoted(o);
return num;
}
#if BB_MMU
#define fetch_till_str(as_string, input, word, skip_tabs) \
fetch_till_str(input, word, skip_tabs)
#endif
static char *fetch_till_str(o_string *as_string,
struct in_str *input,
const char *word,
int heredoc_flags)
{
o_string heredoc = NULL_O_STRING;
unsigned past_EOL;
int prev = 0; /* not \ */
int ch;
goto jump_in;
while (1) {
ch = i_getch(input);
if (ch != EOF)
nommu_addchr(as_string, ch);
if ((ch == '\n' || ch == EOF)
&& ((heredoc_flags & HEREDOC_QUOTED) || prev != '\\')
) {
if (strcmp(heredoc.data + past_EOL, word) == 0) {
heredoc.data[past_EOL] = '\0';
debug_printf_parse("parsed heredoc '%s'\n", heredoc.data);
return heredoc.data;
}
while (ch == '\n') {
o_addchr(&heredoc, ch);
prev = ch;
jump_in:
past_EOL = heredoc.length;
do {
ch = i_getch(input);
if (ch != EOF)
nommu_addchr(as_string, ch);
} while ((heredoc_flags & HEREDOC_SKIPTABS) && ch == '\t');
}
}
if (ch == EOF) {
o_free_unsafe(&heredoc);
return NULL;
}
o_addchr(&heredoc, ch);
nommu_addchr(as_string, ch);
if (prev == '\\' && ch == '\\')
/* Correctly handle foo\\<eol> (not a line cont.) */
prev = 0; /* not \ */
else
prev = ch;
}
}
/* Look at entire parse tree for not-yet-loaded REDIRECT_HEREDOCs
* and load them all. There should be exactly heredoc_cnt of them.
*/
static int fetch_heredocs(int heredoc_cnt, struct parse_context *ctx, struct in_str *input)
{
struct pipe *pi = ctx->list_head;
while (pi && heredoc_cnt) {
int i;
struct command *cmd = pi->cmds;
debug_printf_parse("fetch_heredocs: num_cmds:%d cmd argv0:'%s'\n",
pi->num_cmds,
cmd->argv ? cmd->argv[0] : "NONE");
for (i = 0; i < pi->num_cmds; i++) {
struct redir_struct *redir = cmd->redirects;
debug_printf_parse("fetch_heredocs: %d cmd argv0:'%s'\n",
i, cmd->argv ? cmd->argv[0] : "NONE");
while (redir) {
if (redir->rd_type == REDIRECT_HEREDOC) {
char *p;
redir->rd_type = REDIRECT_HEREDOC2;
/* redir->rd_dup is (ab)used to indicate <<- */
p = fetch_till_str(&ctx->as_string, input,
redir->rd_filename, redir->rd_dup);
if (!p) {
syntax_error("unexpected EOF in here document");
return 1;
}
free(redir->rd_filename);
redir->rd_filename = p;
heredoc_cnt--;
}
redir = redir->next;
}
cmd++;
}
pi = pi->next;
}
#if 0
/* Should be 0. If it isn't, it's a parse error */
if (heredoc_cnt)
bb_error_msg_and_die("heredoc BUG 2");
#endif
return 0;
}
static int run_list(struct pipe *pi);
#if BB_MMU
#define parse_stream(pstring, input, end_trigger) \
parse_stream(input, end_trigger)
#endif
static struct pipe *parse_stream(char **pstring,
struct in_str *input,
int end_trigger);
#if !ENABLE_HUSH_FUNCTIONS
#define parse_group(dest, ctx, input, ch) \
parse_group(ctx, input, ch)
#endif
static int parse_group(o_string *dest, struct parse_context *ctx,
struct in_str *input, int ch)
{
/* dest contains characters seen prior to ( or {.
* Typically it's empty, but for function defs,
* it contains function name (without '()'). */
struct pipe *pipe_list;
int endch;
struct command *command = ctx->command;
debug_printf_parse("parse_group entered\n");
#if ENABLE_HUSH_FUNCTIONS
if (ch == '(' && !dest->has_quoted_part) {
if (dest->length)
if (done_word(dest, ctx))
return 1;
if (!command->argv)
goto skip; /* (... */
if (command->argv[1]) { /* word word ... (... */
syntax_error_unexpected_ch('(');
return 1;
}
/* it is "word(..." or "word (..." */
do
ch = i_getch(input);
while (ch == ' ' || ch == '\t');
if (ch != ')') {
syntax_error_unexpected_ch(ch);
return 1;
}
nommu_addchr(&ctx->as_string, ch);
do
ch = i_getch(input);
while (ch == ' ' || ch == '\t' || ch == '\n');
if (ch != '{') {
syntax_error_unexpected_ch(ch);
return 1;
}
nommu_addchr(&ctx->as_string, ch);
command->cmd_type = CMD_FUNCDEF;
goto skip;
}
#endif
#if 0 /* Prevented by caller */
if (command->argv /* word [word]{... */
|| dest->length /* word{... */
|| dest->has_quoted_part /* ""{... */
) {
syntax_error(NULL);
debug_printf_parse("parse_group return 1: "
"syntax error, groups and arglists don't mix\n");
return 1;
}
#endif
#if ENABLE_HUSH_FUNCTIONS
skip:
#endif
endch = '}';
if (ch == '(') {
endch = ')';
command->cmd_type = CMD_SUBSHELL;
} else {
/* bash does not allow "{echo...", requires whitespace */
ch = i_getch(input);
if (ch != ' ' && ch != '\t' && ch != '\n') {
syntax_error_unexpected_ch(ch);
return 1;
}
nommu_addchr(&ctx->as_string, ch);
}
{
#if BB_MMU
# define as_string NULL
#else
char *as_string = NULL;
#endif
pipe_list = parse_stream(&as_string, input, endch);
#if !BB_MMU
if (as_string)
o_addstr(&ctx->as_string, as_string);
#endif
/* empty ()/{} or parse error? */
if (!pipe_list || pipe_list == ERR_PTR) {
/* parse_stream already emitted error msg */
if (!BB_MMU)
free(as_string);
debug_printf_parse("parse_group return 1: "
"parse_stream returned %p\n", pipe_list);
return 1;
}
command->group = pipe_list;
#if !BB_MMU
as_string[strlen(as_string) - 1] = '\0'; /* plink ')' or '}' */
command->group_as_string = as_string;
debug_printf_parse("end of group, remembering as:'%s'\n",
command->group_as_string);
#endif
#undef as_string
}
debug_printf_parse("parse_group return 0\n");
return 0;
/* command remains "open", available for possible redirects */
}
#if ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_DOLLAR_OPS
/* Subroutines for copying $(...) and `...` things */
static int add_till_backquote(o_string *dest, struct in_str *input, int in_dquote);
/* '...' */
static int add_till_single_quote(o_string *dest, struct in_str *input)
{
while (1) {
int ch = i_getch(input);
if (ch == EOF) {
syntax_error_unterm_ch('\'');
return 0;
}
if (ch == '\'')
return 1;
o_addchr(dest, ch);
}
}
/* "...\"...`..`...." - do we need to handle "...$(..)..." too? */
static int add_till_double_quote(o_string *dest, struct in_str *input)
{
while (1) {
int ch = i_getch(input);
if (ch == EOF) {
syntax_error_unterm_ch('"');
return 0;
}
if (ch == '"')
return 1;
if (ch == '\\') { /* \x. Copy both chars. */
o_addchr(dest, ch);
ch = i_getch(input);
}
o_addchr(dest, ch);
if (ch == '`') {
if (!add_till_backquote(dest, input, /*in_dquote:*/ 1))
return 0;
o_addchr(dest, ch);
continue;
}
//if (ch == '$') ...
}
}
/* Process `cmd` - copy contents until "`" is seen. Complicated by
* \` quoting.
* "Within the backquoted style of command substitution, backslash
* shall retain its literal meaning, except when followed by: '$', '`', or '\'.
* The search for the matching backquote shall be satisfied by the first
* backquote found without a preceding backslash; during this search,
* if a non-escaped backquote is encountered within a shell comment,
* a here-document, an embedded command substitution of the $(command)
* form, or a quoted string, undefined results occur. A single-quoted
* or double-quoted string that begins, but does not end, within the
* "`...`" sequence produces undefined results."
* Example Output
* echo `echo '\'TEST\`echo ZZ\`BEST` \TESTZZBEST
*/
static int add_till_backquote(o_string *dest, struct in_str *input, int in_dquote)
{
while (1) {
int ch = i_getch(input);
if (ch == '`')
return 1;
if (ch == '\\') {
/* \x. Copy both unless it is \`, \$, \\ and maybe \" */
ch = i_getch(input);
if (ch != '`'
&& ch != '$'
&& ch != '\\'
&& (!in_dquote || ch != '"')
) {
o_addchr(dest, '\\');
}
}
if (ch == EOF) {
syntax_error_unterm_ch('`');
return 0;
}
o_addchr(dest, ch);
}
}
/* Process $(cmd) - copy contents until ")" is seen. Complicated by
* quoting and nested ()s.
* "With the $(command) style of command substitution, all characters
* following the open parenthesis to the matching closing parenthesis
* constitute the command. Any valid shell script can be used for command,
* except a script consisting solely of redirections which produces
* unspecified results."
* Example Output
* echo $(echo '(TEST)' BEST) (TEST) BEST
* echo $(echo 'TEST)' BEST) TEST) BEST
* echo $(echo \(\(TEST\) BEST) ((TEST) BEST
*
* Also adapted to eat ${var%...} and $((...)) constructs, since ... part
* can contain arbitrary constructs, just like $(cmd).
* In bash compat mode, it needs to also be able to stop on ':' or '/'
* for ${var:N[:M]} and ${var/P[/R]} parsing.
*/
#define DOUBLE_CLOSE_CHAR_FLAG 0x80
static int add_till_closing_bracket(o_string *dest, struct in_str *input, unsigned end_ch)
{
int ch;
char dbl = end_ch & DOUBLE_CLOSE_CHAR_FLAG;
# if ENABLE_HUSH_BASH_COMPAT
char end_char2 = end_ch >> 8;
# endif
end_ch &= (DOUBLE_CLOSE_CHAR_FLAG - 1);
while (1) {
ch = i_getch(input);
if (ch == EOF) {
syntax_error_unterm_ch(end_ch);
return 0;
}
if (ch == end_ch IF_HUSH_BASH_COMPAT( || ch == end_char2)) {
if (!dbl)
break;
/* we look for closing )) of $((EXPR)) */
if (i_peek(input) == end_ch) {
i_getch(input); /* eat second ')' */
break;
}
}
o_addchr(dest, ch);
if (ch == '(' || ch == '{') {
ch = (ch == '(' ? ')' : '}');
if (!add_till_closing_bracket(dest, input, ch))
return 0;
o_addchr(dest, ch);
continue;
}
if (ch == '\'') {
if (!add_till_single_quote(dest, input))
return 0;
o_addchr(dest, ch);
continue;
}
if (ch == '"') {
if (!add_till_double_quote(dest, input))
return 0;
o_addchr(dest, ch);
continue;
}
if (ch == '`') {
if (!add_till_backquote(dest, input, /*in_dquote:*/ 0))
return 0;
o_addchr(dest, ch);
continue;
}
if (ch == '\\') {
/* \x. Copy verbatim. Important for \(, \) */
ch = i_getch(input);
if (ch == EOF) {
syntax_error_unterm_ch(')');
return 0;
}
o_addchr(dest, ch);
continue;
}
}
return ch;
}
#endif /* ENABLE_HUSH_TICK || ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_DOLLAR_OPS */
/* Return code: 0 for OK, 1 for syntax error */
#if BB_MMU
#define parse_dollar(as_string, dest, input, quote_mask) \
parse_dollar(dest, input, quote_mask)
#define as_string NULL
#endif
static int parse_dollar(o_string *as_string,
o_string *dest,
struct in_str *input, unsigned char quote_mask)
{
int ch = i_peek(input); /* first character after the $ */
debug_printf_parse("parse_dollar entered: ch='%c'\n", ch);
if (isalpha(ch)) {
ch = i_getch(input);
nommu_addchr(as_string, ch);
make_var:
o_addchr(dest, SPECIAL_VAR_SYMBOL);
while (1) {
debug_printf_parse(": '%c'\n", ch);
o_addchr(dest, ch | quote_mask);
quote_mask = 0;
ch = i_peek(input);
if (!isalnum(ch) && ch != '_')
break;
ch = i_getch(input);
nommu_addchr(as_string, ch);
}
o_addchr(dest, SPECIAL_VAR_SYMBOL);
} else if (isdigit(ch)) {
make_one_char_var:
ch = i_getch(input);
nommu_addchr(as_string, ch);
o_addchr(dest, SPECIAL_VAR_SYMBOL);
debug_printf_parse(": '%c'\n", ch);
o_addchr(dest, ch | quote_mask);
o_addchr(dest, SPECIAL_VAR_SYMBOL);
} else switch (ch) {
case '$': /* pid */
case '!': /* last bg pid */
case '?': /* last exit code */
case '#': /* number of args */
case '*': /* args */
case '@': /* args */
goto make_one_char_var;
case '{': {
o_addchr(dest, SPECIAL_VAR_SYMBOL);
ch = i_getch(input); /* eat '{' */
nommu_addchr(as_string, ch);
ch = i_getch(input); /* first char after '{' */
/* It should be ${?}, or ${#var},
* or even ${?+subst} - operator acting on a special variable,
* or the beginning of variable name.
*/
if (ch == EOF
|| (!strchr(_SPECIAL_VARS_STR, ch) && !isalnum(ch)) /* not one of those */
) {
bad_dollar_syntax:
syntax_error_unterm_str("${name}");
debug_printf_parse("parse_dollar return 0: unterminated ${name}\n");
return 0;
}
nommu_addchr(as_string, ch);
ch |= quote_mask;
/* It's possible to just call add_till_closing_bracket() at this point.
* However, this regresses some of our testsuite cases
* which check invalid constructs like ${%}.
* Oh well... let's check that the var name part is fine... */
while (1) {
unsigned pos;
o_addchr(dest, ch);
debug_printf_parse(": '%c'\n", ch);
ch = i_getch(input);
nommu_addchr(as_string, ch);
if (ch == '}')
break;
if (!isalnum(ch) && ch != '_') {
unsigned end_ch;
unsigned char last_ch;
/* handle parameter expansions
* http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_02
*/
if (!strchr(VAR_SUBST_OPS, ch)) /* ${var<bad_char>... */
goto bad_dollar_syntax;
/* Eat everything until closing '}' (or ':') */
end_ch = '}';
if (ENABLE_HUSH_BASH_COMPAT
&& ch == ':'
&& !strchr(MINUS_PLUS_EQUAL_QUESTION, i_peek(input))
) {
/* It's ${var:N[:M]} thing */
end_ch = '}' * 0x100 + ':';
}
if (ENABLE_HUSH_BASH_COMPAT
&& ch == '/'
) {
/* It's ${var/[/]pattern[/repl]} thing */
if (i_peek(input) == '/') { /* ${var//pattern[/repl]}? */
i_getch(input);
nommu_addchr(as_string, '/');
ch = '\\';
}
end_ch = '}' * 0x100 + '/';
}
o_addchr(dest, ch);
again:
if (!BB_MMU)
pos = dest->length;
#if ENABLE_HUSH_DOLLAR_OPS
last_ch = add_till_closing_bracket(dest, input, end_ch);
if (last_ch == 0) /* error? */
return 0;
#else
#error Simple code to only allow ${var} is not implemented
#endif
if (as_string) {
o_addstr(as_string, dest->data + pos);
o_addchr(as_string, last_ch);
}
if (ENABLE_HUSH_BASH_COMPAT && (end_ch & 0xff00)) {
/* close the first block: */
o_addchr(dest, SPECIAL_VAR_SYMBOL);
/* while parsing N from ${var:N[:M]}
* or pattern from ${var/[/]pattern[/repl]} */
if ((end_ch & 0xff) == last_ch) {
/* got ':' or '/'- parse the rest */
end_ch = '}';
goto again;
}
/* got '}' */
if (end_ch == '}' * 0x100 + ':') {
/* it's ${var:N} - emulate :999999999 */
o_addstr(dest, "999999999");
} /* else: it's ${var/[/]pattern} */
}
break;
}
}
o_addchr(dest, SPECIAL_VAR_SYMBOL);
break;
}
#if ENABLE_SH_MATH_SUPPORT || ENABLE_HUSH_TICK
case '(': {
unsigned pos;
ch = i_getch(input);
nommu_addchr(as_string, ch);
# if ENABLE_SH_MATH_SUPPORT
if (i_peek(input) == '(') {
ch = i_getch(input);
nommu_addchr(as_string, ch);
o_addchr(dest, SPECIAL_VAR_SYMBOL);
o_addchr(dest, /*quote_mask |*/ '+');
if (!BB_MMU)
pos = dest->length;
if (!add_till_closing_bracket(dest, input, ')' | DOUBLE_CLOSE_CHAR_FLAG))
return 0; /* error */
if (as_string) {
o_addstr(as_string, dest->data + pos);
o_addchr(as_string, ')');
o_addchr(as_string, ')');
}
o_addchr(dest, SPECIAL_VAR_SYMBOL);
break;
}
# endif
# if ENABLE_HUSH_TICK
o_addchr(dest, SPECIAL_VAR_SYMBOL);
o_addchr(dest, quote_mask | '`');
if (!BB_MMU)
pos = dest->length;
if (!add_till_closing_bracket(dest, input, ')'))
return 0; /* error */
if (as_string) {
o_addstr(as_string, dest->data + pos);
o_addchr(as_string, ')');
}
o_addchr(dest, SPECIAL_VAR_SYMBOL);
# endif
break;
}
#endif
case '_':
ch = i_getch(input);
nommu_addchr(as_string, ch);
ch = i_peek(input);
if (isalnum(ch)) { /* it's $_name or $_123 */
ch = '_';
goto make_var;
}
/* else: it's $_ */
/* TODO: $_ and $-: */
/* $_ Shell or shell script name; or last argument of last command
* (if last command wasn't a pipe; if it was, bash sets $_ to "");
* but in command's env, set to full pathname used to invoke it */
/* $- Option flags set by set builtin or shell options (-i etc) */
default:
o_addQchr(dest, '$');
}
debug_printf_parse("parse_dollar return 1 (ok)\n");
return 1;
#undef as_string
}
#if BB_MMU
# if ENABLE_HUSH_BASH_COMPAT
#define encode_string(as_string, dest, input, dquote_end, process_bkslash) \
encode_string(dest, input, dquote_end, process_bkslash)
# else
/* only ${var/pattern/repl} (its pattern part) needs additional mode */
#define encode_string(as_string, dest, input, dquote_end, process_bkslash) \
encode_string(dest, input, dquote_end)
# endif
#define as_string NULL
#else /* !MMU */
# if ENABLE_HUSH_BASH_COMPAT
/* all parameters are needed, no macro tricks */
# else
#define encode_string(as_string, dest, input, dquote_end, process_bkslash) \
encode_string(as_string, dest, input, dquote_end)
# endif
#endif
static int encode_string(o_string *as_string,
o_string *dest,
struct in_str *input,
int dquote_end,
int process_bkslash)
{
#if !ENABLE_HUSH_BASH_COMPAT
const int process_bkslash = 1;
#endif
int ch;
int next;
again:
ch = i_getch(input);
if (ch != EOF)
nommu_addchr(as_string, ch);
if (ch == dquote_end) { /* may be only '"' or EOF */
debug_printf_parse("encode_string return 1 (ok)\n");
return 1;
}
/* note: can't move it above ch == dquote_end check! */
if (ch == EOF) {
syntax_error_unterm_ch('"');
return 0; /* error */
}
next = '\0';
if (ch != '\n') {
next = i_peek(input);
}
debug_printf_parse("\" ch=%c (%d) escape=%d\n",
ch, ch, !!(dest->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
if (process_bkslash && ch == '\\') {
if (next == EOF) {
syntax_error("\\<eof>");
xfunc_die();
}
/* bash:
* "The backslash retains its special meaning [in "..."]
* only when followed by one of the following characters:
* $, `, ", \, or <newline>. A double quote may be quoted
* within double quotes by preceding it with a backslash."
* NB: in (unquoted) heredoc, above does not apply to ",
* therefore we check for it by "next == dquote_end" cond.
*/
if (next == dquote_end || strchr("$`\\\n", next)) {
ch = i_getch(input); /* eat next */
if (ch == '\n')
goto again; /* skip \<newline> */
} /* else: ch remains == '\\', and we double it below: */
o_addqchr(dest, ch); /* \c if c is a glob char, else just c */
nommu_addchr(as_string, ch);
goto again;
}
if (ch == '$') {
if (!parse_dollar(as_string, dest, input, /*quote_mask:*/ 0x80)) {
debug_printf_parse("encode_string return 0: "
"parse_dollar returned 0 (error)\n");
return 0;
}
goto again;
}
#if ENABLE_HUSH_TICK
if (ch == '`') {
//unsigned pos = dest->length;
o_addchr(dest, SPECIAL_VAR_SYMBOL);
o_addchr(dest, 0x80 | '`');
if (!add_till_backquote(dest, input, /*in_dquote:*/ dquote_end == '"'))
return 0; /* error */
o_addchr(dest, SPECIAL_VAR_SYMBOL);
//debug_printf_subst("SUBST RES3 '%s'\n", dest->data + pos);
goto again;
}
#endif
o_addQchr(dest, ch);
goto again;
#undef as_string
}
/*
* Scan input until EOF or end_trigger char.
* Return a list of pipes to execute, or NULL on EOF
* or if end_trigger character is met.
* On syntax error, exit if shell is not interactive,
* reset parsing machinery and start parsing anew,
* or return ERR_PTR.
*/
static struct pipe *parse_stream(char **pstring,
struct in_str *input,
int end_trigger)
{
struct parse_context ctx;
o_string dest = NULL_O_STRING;
int heredoc_cnt;
/* Single-quote triggers a bypass of the main loop until its mate is
* found. When recursing, quote state is passed in via dest->o_expflags.
*/
debug_printf_parse("parse_stream entered, end_trigger='%c'\n",
end_trigger ? end_trigger : 'X');
debug_enter();
/* If very first arg is "" or '', dest.data may end up NULL.
* Preventing this: */
o_addchr(&dest, '\0');
dest.length = 0;
/* We used to separate words on $IFS here. This was wrong.
* $IFS is used only for word splitting when $var is expanded,
* here we should use blank chars as separators, not $IFS
*/
if (MAYBE_ASSIGNMENT != 0)
dest.o_assignment = MAYBE_ASSIGNMENT;
initialize_context(&ctx);
heredoc_cnt = 0;
while (1) {
const char *is_blank;
const char *is_special;
int ch;
int next;
int redir_fd;
redir_type redir_style;
ch = i_getch(input);
debug_printf_parse(": ch=%c (%d) escape=%d\n",
ch, ch, !!(dest.o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
if (ch == EOF) {
struct pipe *pi;
if (heredoc_cnt) {
syntax_error_unterm_str("here document");
goto parse_error;
}
/* end_trigger == '}' case errors out earlier,
* checking only ')' */
if (end_trigger == ')') {
syntax_error_unterm_ch('(');
goto parse_error;
}
if (done_word(&dest, &ctx)) {
goto parse_error;
}
o_free(&dest);
done_pipe(&ctx, PIPE_SEQ);
pi = ctx.list_head;
/* If we got nothing... */
/* (this makes bare "&" cmd a no-op.
* bash says: "syntax error near unexpected token '&'") */
if (pi->num_cmds == 0
IF_HAS_KEYWORDS( && pi->res_word == RES_NONE)
) {
free_pipe_list(pi);
pi = NULL;
}
#if !BB_MMU
debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
if (pstring)
*pstring = ctx.as_string.data;
else
o_free_unsafe(&ctx.as_string);
#endif
debug_leave();
debug_printf_parse("parse_stream return %p\n", pi);
return pi;
}
nommu_addchr(&ctx.as_string, ch);
next = '\0';
if (ch != '\n')
next = i_peek(input);
is_special = "{}<>;&|()#'" /* special outside of "str" */
"\\$\"" IF_HUSH_TICK("`"); /* always special */
/* Are { and } special here? */
if (ctx.command->argv /* word [word]{... - non-special */
|| dest.length /* word{... - non-special */
|| dest.has_quoted_part /* ""{... - non-special */
|| (next != ';' /* }; - special */
&& next != ')' /* }) - special */
&& next != '&' /* }& and }&& ... - special */
&& next != '|' /* }|| ... - special */
&& !strchr(defifs, next) /* {word - non-special */
)
) {
/* They are not special, skip "{}" */
is_special += 2;
}
is_special = strchr(is_special, ch);
is_blank = strchr(defifs, ch);
if (!is_special && !is_blank) { /* ordinary char */
ordinary_char:
o_addQchr(&dest, ch);
if ((dest.o_assignment == MAYBE_ASSIGNMENT
|| dest.o_assignment == WORD_IS_KEYWORD)
&& ch == '='
&& is_well_formed_var_name(dest.data, '=')
) {
dest.o_assignment = DEFINITELY_ASSIGNMENT;
debug_printf_parse("dest.o_assignment='%s'\n", assignment_flag[dest.o_assignment]);
}
continue;
}
if (is_blank) {
if (done_word(&dest, &ctx)) {
goto parse_error;
}
if (ch == '\n') {
/* Is this a case when newline is simply ignored?
* Some examples:
* "cmd | <newline> cmd ..."
* "case ... in <newline> word) ..."
*/
if (IS_NULL_CMD(ctx.command)
&& dest.length == 0 && !dest.has_quoted_part
) {
/* This newline can be ignored. But...
* Without check #1, interactive shell
* ignores even bare <newline>,
* and shows the continuation prompt:
* ps1_prompt$ <enter>
* ps2> _ <=== wrong, should be ps1
* Without check #2, "cmd & <newline>"
* is similarly mistreated.
* (BTW, this makes "cmd & cmd"
* and "cmd && cmd" non-orthogonal.
* Really, ask yourself, why
* "cmd && <newline>" doesn't start
* cmd but waits for more input?
* No reason...)
*/
struct pipe *pi = ctx.list_head;
if (pi->num_cmds != 0 /* check #1 */
&& pi->followup != PIPE_BG /* check #2 */
) {
continue;
}
}
/* Treat newline as a command separator. */
done_pipe(&ctx, PIPE_SEQ);
debug_printf_parse("heredoc_cnt:%d\n", heredoc_cnt);
if (heredoc_cnt) {
if (fetch_heredocs(heredoc_cnt, &ctx, input)) {
goto parse_error;
}
heredoc_cnt = 0;
}
dest.o_assignment = MAYBE_ASSIGNMENT;
debug_printf_parse("dest.o_assignment='%s'\n", assignment_flag[dest.o_assignment]);
ch = ';';
/* note: if (is_blank) continue;
* will still trigger for us */
}
}
/* "cmd}" or "cmd }..." without semicolon or &:
* } is an ordinary char in this case, even inside { cmd; }
* Pathological example: { ""}; } should exec "}" cmd
*/
if (ch == '}') {
if (!IS_NULL_CMD(ctx.command) /* cmd } */
|| dest.length != 0 /* word} */
|| dest.has_quoted_part /* ""} */
) {
goto ordinary_char;
}
if (!IS_NULL_PIPE(ctx.pipe)) /* cmd | } */
goto skip_end_trigger;
/* else: } does terminate a group */
}
if (end_trigger && end_trigger == ch
&& (ch != ';' || heredoc_cnt == 0)
#if ENABLE_HUSH_CASE
&& (ch != ')'
|| ctx.ctx_res_w != RES_MATCH
|| (!dest.has_quoted_part && strcmp(dest.data, "esac") == 0)
)
#endif
) {
if (heredoc_cnt) {
/* This is technically valid:
* { cat <<HERE; }; echo Ok
* heredoc
* heredoc
* HERE
* but we don't support this.
* We require heredoc to be in enclosing {}/(),
* if any.
*/
syntax_error_unterm_str("here document");
goto parse_error;
}
if (done_word(&dest, &ctx)) {
goto parse_error;
}
done_pipe(&ctx, PIPE_SEQ);
dest.o_assignment = MAYBE_ASSIGNMENT;
debug_printf_parse("dest.o_assignment='%s'\n", assignment_flag[dest.o_assignment]);
/* Do we sit outside of any if's, loops or case's? */
if (!HAS_KEYWORDS
IF_HAS_KEYWORDS(|| (ctx.ctx_res_w == RES_NONE && ctx.old_flag == 0))
) {
o_free(&dest);
#if !BB_MMU
debug_printf_parse("as_string '%s'\n", ctx.as_string.data);
if (pstring)
*pstring = ctx.as_string.data;
else
o_free_unsafe(&ctx.as_string);
#endif
debug_leave();
debug_printf_parse("parse_stream return %p: "
"end_trigger char found\n",
ctx.list_head);
return ctx.list_head;
}
}
skip_end_trigger:
if (is_blank)
continue;
/* Catch <, > before deciding whether this word is
* an assignment. a=1 2>z b=2: b=2 is still assignment */
switch (ch) {
case '>':
redir_fd = redirect_opt_num(&dest);
if (done_word(&dest, &ctx)) {
goto parse_error;
}
redir_style = REDIRECT_OVERWRITE;
if (next == '>') {
redir_style = REDIRECT_APPEND;
ch = i_getch(input);
nommu_addchr(&ctx.as_string, ch);
}
#if 0
else if (next == '(') {
syntax_error(">(process) not supported");
goto parse_error;
}
#endif
if (parse_redirect(&ctx, redir_fd, redir_style, input))
goto parse_error;
continue; /* back to top of while (1) */
case '<':
redir_fd = redirect_opt_num(&dest);
if (done_word(&dest, &ctx)) {
goto parse_error;
}
redir_style = REDIRECT_INPUT;
if (next == '<') {
redir_style = REDIRECT_HEREDOC;
heredoc_cnt++;
debug_printf_parse("++heredoc_cnt=%d\n", heredoc_cnt);
ch = i_getch(input);
nommu_addchr(&ctx.as_string, ch);
} else if (next == '>') {
redir_style = REDIRECT_IO;
ch = i_getch(input);
nommu_addchr(&ctx.as_string, ch);
}
#if 0
else if (next == '(') {
syntax_error("<(process) not supported");
goto parse_error;
}
#endif
if (parse_redirect(&ctx, redir_fd, redir_style, input))
goto parse_error;
continue; /* back to top of while (1) */
case '#':
if (dest.length == 0 && !dest.has_quoted_part) {
/* skip "#comment" */
while (1) {
ch = i_peek(input);
if (ch == EOF || ch == '\n')
break;
i_getch(input);
/* note: we do not add it to &ctx.as_string */
}
nommu_addchr(&ctx.as_string, '\n');
continue; /* back to top of while (1) */
}
break;
case '\\':
if (next == '\n') {
/* It's "\<newline>" */
#if !BB_MMU
/* Remove trailing '\' from ctx.as_string */
ctx.as_string.data[--ctx.as_string.length] = '\0';
#endif
ch = i_getch(input); /* eat it */
continue; /* back to top of while (1) */
}
break;
}
if (dest.o_assignment == MAYBE_ASSIGNMENT
/* check that we are not in word in "a=1 2>word b=1": */
&& !ctx.pending_redirect
) {
/* ch is a special char and thus this word
* cannot be an assignment */
dest.o_assignment = NOT_ASSIGNMENT;
debug_printf_parse("dest.o_assignment='%s'\n", assignment_flag[dest.o_assignment]);
}
/* Note: nommu_addchr(&ctx.as_string, ch) is already done */
switch (ch) {
case '#': /* non-comment #: "echo a#b" etc */
o_addQchr(&dest, ch);
break;
case '\\':
if (next == EOF) {
syntax_error("\\<eof>");
xfunc_die();
}
ch = i_getch(input);
/* note: ch != '\n' (that case does not reach this place) */
o_addchr(&dest, '\\');
/*nommu_addchr(&ctx.as_string, '\\'); - already done */
o_addchr(&dest, ch);
nommu_addchr(&ctx.as_string, ch);
/* Example: echo Hello \2>file
* we need to know that word 2 is quoted */
dest.has_quoted_part = 1;
break;
case '$':
if (!parse_dollar(&ctx.as_string, &dest, input, /*quote_mask:*/ 0)) {
debug_printf_parse("parse_stream parse error: "
"parse_dollar returned 0 (error)\n");
goto parse_error;
}
break;
case '\'':
dest.has_quoted_part = 1;
if (next == '\'' && !ctx.pending_redirect) {
insert_empty_quoted_str_marker:
nommu_addchr(&ctx.as_string, next);
i_getch(input); /* eat second ' */
o_addchr(&dest, SPECIAL_VAR_SYMBOL);
o_addchr(&dest, SPECIAL_VAR_SYMBOL);
} else {
while (1) {
ch = i_getch(input);
if (ch == EOF) {
syntax_error_unterm_ch('\'');
goto parse_error;
}
nommu_addchr(&ctx.as_string, ch);
if (ch == '\'')
break;
o_addqchr(&dest, ch);
}
}
break;
case '"':
dest.has_quoted_part = 1;
if (next == '"' && !ctx.pending_redirect)
goto insert_empty_quoted_str_marker;
if (dest.o_assignment == NOT_ASSIGNMENT)
dest.o_expflags |= EXP_FLAG_ESC_GLOB_CHARS;
if (!encode_string(&ctx.as_string, &dest, input, '"', /*process_bkslash:*/ 1))
goto parse_error;
dest.o_expflags &= ~EXP_FLAG_ESC_GLOB_CHARS;
break;
#if ENABLE_HUSH_TICK
case '`': {
USE_FOR_NOMMU(unsigned pos;)
o_addchr(&dest, SPECIAL_VAR_SYMBOL);
o_addchr(&dest, '`');
USE_FOR_NOMMU(pos = dest.length;)
if (!add_till_backquote(&dest, input, /*in_dquote:*/ 0))
goto parse_error;
# if !BB_MMU
o_addstr(&ctx.as_string, dest.data + pos);
o_addchr(&ctx.as_string, '`');
# endif
o_addchr(&dest, SPECIAL_VAR_SYMBOL);
//debug_printf_subst("SUBST RES3 '%s'\n", dest.data + pos);
break;
}
#endif
case ';':
#if ENABLE_HUSH_CASE
case_semi:
#endif
if (done_word(&dest, &ctx)) {
goto parse_error;
}
done_pipe(&ctx, PIPE_SEQ);
#if ENABLE_HUSH_CASE
/* Eat multiple semicolons, detect
* whether it means something special */
while (1) {
ch = i_peek(input);
if (ch != ';')
break;
ch = i_getch(input);
nommu_addchr(&ctx.as_string, ch);
if (ctx.ctx_res_w == RES_CASE_BODY) {
ctx.ctx_dsemicolon = 1;
ctx.ctx_res_w = RES_MATCH;
break;
}
}
#endif
new_cmd:
/* We just finished a cmd. New one may start
* with an assignment */
dest.o_assignment = MAYBE_ASSIGNMENT;
debug_printf_parse("dest.o_assignment='%s'\n", assignment_flag[dest.o_assignment]);
break;
case '&':
if (done_word(&dest, &ctx)) {
goto parse_error;
}
if (next == '&') {
ch = i_getch(input);
nommu_addchr(&ctx.as_string, ch);
done_pipe(&ctx, PIPE_AND);
} else {
done_pipe(&ctx, PIPE_BG);
}
goto new_cmd;
case '|':
if (done_word(&dest, &ctx)) {
goto parse_error;
}
#if ENABLE_HUSH_CASE
if (ctx.ctx_res_w == RES_MATCH)
break; /* we are in case's "word | word)" */
#endif
if (next == '|') { /* || */
ch = i_getch(input);
nommu_addchr(&ctx.as_string, ch);
done_pipe(&ctx, PIPE_OR);
} else {
/* we could pick up a file descriptor choice here
* with redirect_opt_num(), but bash doesn't do it.
* "echo foo 2| cat" yields "foo 2". */
done_command(&ctx);
#if !BB_MMU
o_reset_to_empty_unquoted(&ctx.as_string);
#endif
}
goto new_cmd;
case '(':
#if ENABLE_HUSH_CASE
/* "case... in [(]word)..." - skip '(' */
if (ctx.ctx_res_w == RES_MATCH
&& ctx.command->argv == NULL /* not (word|(... */
&& dest.length == 0 /* not word(... */
&& dest.has_quoted_part == 0 /* not ""(... */
) {
continue;
}
#endif
case '{':
if (parse_group(&dest, &ctx, input, ch) != 0) {
goto parse_error;
}
goto new_cmd;
case ')':
#if ENABLE_HUSH_CASE
if (ctx.ctx_res_w == RES_MATCH)
goto case_semi;
#endif
case '}':
/* proper use of this character is caught by end_trigger:
* if we see {, we call parse_group(..., end_trigger='}')
* and it will match } earlier (not here). */
syntax_error_unexpected_ch(ch);
goto parse_error;
default:
if (HUSH_DEBUG)
bb_error_msg_and_die("BUG: unexpected %c\n", ch);
}
} /* while (1) */
parse_error:
{
struct parse_context *pctx;
IF_HAS_KEYWORDS(struct parse_context *p2;)
/* Clean up allocated tree.
* Sample for finding leaks on syntax error recovery path.
* Run it from interactive shell, watch pmap `pidof hush`.
* while if false; then false; fi; do break; fi
* Samples to catch leaks at execution:
* while if (true | {true;}); then echo ok; fi; do break; done
* while if (true | {true;}); then echo ok; fi; do (if echo ok; break; then :; fi) | cat; break; done
*/
pctx = &ctx;
do {
/* Update pipe/command counts,
* otherwise freeing may miss some */
done_pipe(pctx, PIPE_SEQ);
debug_printf_clean("freeing list %p from ctx %p\n",
pctx->list_head, pctx);
debug_print_tree(pctx->list_head, 0);
free_pipe_list(pctx->list_head);
debug_printf_clean("freed list %p\n", pctx->list_head);
#if !BB_MMU
o_free_unsafe(&pctx->as_string);
#endif
IF_HAS_KEYWORDS(p2 = pctx->stack;)
if (pctx != &ctx) {
free(pctx);
}
IF_HAS_KEYWORDS(pctx = p2;)
} while (HAS_KEYWORDS && pctx);
o_free(&dest);
G.last_exitcode = 1;
#if !BB_MMU
if (pstring)
*pstring = NULL;
#endif
debug_leave();
return ERR_PTR;
}
}
/*** Execution routines ***/
/* Expansion can recurse, need forward decls: */
#if !ENABLE_HUSH_BASH_COMPAT
/* only ${var/pattern/repl} (its pattern part) needs additional mode */
#define expand_string_to_string(str, do_unbackslash) \
expand_string_to_string(str)
#endif
static char *expand_string_to_string(const char *str, int do_unbackslash);
#if ENABLE_HUSH_TICK
static int process_command_subs(o_string *dest, const char *s);
#endif
/* expand_strvec_to_strvec() takes a list of strings, expands
* all variable references within and returns a pointer to
* a list of expanded strings, possibly with larger number
* of strings. (Think VAR="a b"; echo $VAR).
* This new list is allocated as a single malloc block.
* NULL-terminated list of char* pointers is at the beginning of it,
* followed by strings themselves.
* Caller can deallocate entire list by single free(list). */
/* A horde of its helpers come first: */
static void o_addblock_duplicate_backslash(o_string *o, const char *str, int len)
{
while (--len >= 0) {
char c = *str++;
#if ENABLE_HUSH_BRACE_EXPANSION
if (c == '{' || c == '}') {
/* { -> \{, } -> \} */
o_addchr(o, '\\');
/* And now we want to add { or } and continue:
* o_addchr(o, c);
* continue;
* luckily, just falling throught achieves this.
*/
}
#endif
o_addchr(o, c);
if (c == '\\') {
/* \z -> \\\z; \<eol> -> \\<eol> */
o_addchr(o, '\\');
if (len) {
len--;
o_addchr(o, '\\');
o_addchr(o, *str++);
}
}
}
}
/* Store given string, finalizing the word and starting new one whenever
* we encounter IFS char(s). This is used for expanding variable values.
* End-of-string does NOT finalize word: think about 'echo -$VAR-'.
* Return in *ended_with_ifs:
* 1 - ended with IFS char, else 0 (this includes case of empty str).
*/
static int expand_on_ifs(int *ended_with_ifs, o_string *output, int n, const char *str)
{
int last_is_ifs = 0;
while (1) {
int word_len;
if (!*str) /* EOL - do not finalize word */
break;
word_len = strcspn(str, G.ifs);
if (word_len) {
/* We have WORD_LEN leading non-IFS chars */
if (!(output->o_expflags & EXP_FLAG_GLOB)) {
o_addblock(output, str, word_len);
} else {
/* Protect backslashes against globbing up :)
* Example: "v='\*'; echo b$v" prints "b\*"
* (and does not try to glob on "*")
*/
o_addblock_duplicate_backslash(output, str, word_len);
/*/ Why can't we do it easier? */
/*o_addblock(output, str, word_len); - WRONG: "v='\*'; echo Z$v" prints "Z*" instead of "Z\*" */
/*o_addqblock(output, str, word_len); - WRONG: "v='*'; echo Z$v" prints "Z*" instead of Z* files */
}
last_is_ifs = 0;
str += word_len;
if (!*str) /* EOL - do not finalize word */
break;
}
/* We know str here points to at least one IFS char */
last_is_ifs = 1;
str += strspn(str, G.ifs); /* skip IFS chars */
if (!*str) /* EOL - do not finalize word */
break;
/* Start new word... but not always! */
/* Case "v=' a'; echo ''$v": we do need to finalize empty word: */
if (output->has_quoted_part
/* Case "v=' a'; echo $v":
* here nothing precedes the space in $v expansion,
* therefore we should not finish the word
* (IOW: if there *is* word to finalize, only then do it):
*/
|| (n > 0 && output->data[output->length - 1])
) {
o_addchr(output, '\0');
debug_print_list("expand_on_ifs", output, n);
n = o_save_ptr(output, n);
}
}
if (ended_with_ifs)
*ended_with_ifs = last_is_ifs;
debug_print_list("expand_on_ifs[1]", output, n);
return n;
}
/* Helper to expand $((...)) and heredoc body. These act as if
* they are in double quotes, with the exception that they are not :).
* Just the rules are similar: "expand only $var and `cmd`"
*
* Returns malloced string.
* As an optimization, we return NULL if expansion is not needed.
*/
#if !ENABLE_HUSH_BASH_COMPAT
/* only ${var/pattern/repl} (its pattern part) needs additional mode */
#define encode_then_expand_string(str, process_bkslash, do_unbackslash) \
encode_then_expand_string(str)
#endif
static char *encode_then_expand_string(const char *str, int process_bkslash, int do_unbackslash)
{
char *exp_str;
struct in_str input;
o_string dest = NULL_O_STRING;
if (!strchr(str, '$')
&& !strchr(str, '\\')
#if ENABLE_HUSH_TICK
&& !strchr(str, '`')
#endif
) {
return NULL;
}
/* We need to expand. Example:
* echo $(($a + `echo 1`)) $((1 + $((2)) ))
*/
setup_string_in_str(&input, str);
encode_string(NULL, &dest, &input, EOF, process_bkslash);
//TODO: error check (encode_string returns 0 on error)?
//bb_error_msg("'%s' -> '%s'", str, dest.data);
exp_str = expand_string_to_string(dest.data, /*unbackslash:*/ do_unbackslash);
//bb_error_msg("'%s' -> '%s'", dest.data, exp_str);
o_free_unsafe(&dest);
return exp_str;
}
#if ENABLE_SH_MATH_SUPPORT
static arith_t expand_and_evaluate_arith(const char *arg, const char **errmsg_p)
{
arith_state_t math_state;
arith_t res;
char *exp_str;
math_state.lookupvar = get_local_var_value;
math_state.setvar = set_local_var_from_halves;
//math_state.endofname = endofname;
exp_str = encode_then_expand_string(arg, /*process_bkslash:*/ 1, /*unbackslash:*/ 1);
res = arith(&math_state, exp_str ? exp_str : arg);
free(exp_str);
if (errmsg_p)
*errmsg_p = math_state.errmsg;
if (math_state.errmsg)
die_if_script(math_state.errmsg);
return res;
}
#endif
#if ENABLE_HUSH_BASH_COMPAT
/* ${var/[/]pattern[/repl]} helpers */
static char *strstr_pattern(char *val, const char *pattern, int *size)
{
while (1) {
char *end = scan_and_match(val, pattern, SCAN_MOVE_FROM_RIGHT + SCAN_MATCH_LEFT_HALF);
debug_printf_varexp("val:'%s' pattern:'%s' end:'%s'\n", val, pattern, end);
if (end) {
*size = end - val;
return val;
}
if (*val == '\0')
return NULL;
/* Optimization: if "*pat" did not match the start of "string",
* we know that "tring", "ring" etc will not match too:
*/
if (pattern[0] == '*')
return NULL;
val++;
}
}
static char *replace_pattern(char *val, const char *pattern, const char *repl, char exp_op)
{
char *result = NULL;
unsigned res_len = 0;
unsigned repl_len = strlen(repl);
while (1) {
int size;
char *s = strstr_pattern(val, pattern, &size);
if (!s)
break;
result = xrealloc(result, res_len + (s - val) + repl_len + 1);
memcpy(result + res_len, val, s - val);
res_len += s - val;
strcpy(result + res_len, repl);
res_len += repl_len;
debug_printf_varexp("val:'%s' s:'%s' result:'%s'\n", val, s, result);
val = s + size;
if (exp_op == '/')
break;
}
if (val[0] && result) {
result = xrealloc(result, res_len + strlen(val) + 1);
strcpy(result + res_len, val);
debug_printf_varexp("val:'%s' result:'%s'\n", val, result);
}
debug_printf_varexp("result:'%s'\n", result);
return result;
}
#endif
/* Helper:
* Handles <SPECIAL_VAR_SYMBOL>varname...<SPECIAL_VAR_SYMBOL> construct.
*/
static NOINLINE const char *expand_one_var(char **to_be_freed_pp, char *arg, char **pp)
{
const char *val = NULL;
char *to_be_freed = NULL;
char *p = *pp;
char *var;
char first_char;
char exp_op;
char exp_save = exp_save; /* for compiler */
char *exp_saveptr; /* points to expansion operator */
char *exp_word = exp_word; /* for compiler */
char arg0;
*p = '\0'; /* replace trailing SPECIAL_VAR_SYMBOL */
var = arg;
exp_saveptr = arg[1] ? strchr(VAR_ENCODED_SUBST_OPS, arg[1]) : NULL;
arg0 = arg[0];
first_char = arg[0] = arg0 & 0x7f;
exp_op = 0;
if (first_char == '#' /* ${#... */
&& arg[1] && !exp_saveptr /* not ${#} and not ${#<op_char>...} */
) {
/* It must be length operator: ${#var} */
var++;
exp_op = 'L';
} else {
/* Maybe handle parameter expansion */
if (exp_saveptr /* if 2nd char is one of expansion operators */
&& strchr(NUMERIC_SPECVARS_STR, first_char) /* 1st char is special variable */
) {
/* ${?:0}, ${#[:]%0} etc */
exp_saveptr = var + 1;
} else {
/* ${?}, ${var}, ${var:0}, ${var[:]%0} etc */
exp_saveptr = var+1 + strcspn(var+1, VAR_ENCODED_SUBST_OPS);
}
exp_op = exp_save = *exp_saveptr;
if (exp_op) {
exp_word = exp_saveptr + 1;
if (exp_op == ':') {
exp_op = *exp_word++;
//TODO: try ${var:} and ${var:bogus} in non-bash config
if (ENABLE_HUSH_BASH_COMPAT
&& (!exp_op || !strchr(MINUS_PLUS_EQUAL_QUESTION, exp_op))
) {
/* oops... it's ${var:N[:M]}, not ${var:?xxx} or some such */
exp_op = ':';
exp_word--;
}
}
*exp_saveptr = '\0';
} /* else: it's not an expansion op, but bare ${var} */
}
/* Look up the variable in question */
if (isdigit(var[0])) {
/* parse_dollar should have vetted var for us */
int n = xatoi_positive(var);
if (n < G.global_argc)
val = G.global_argv[n];
/* else val remains NULL: $N with too big N */
} else {
switch (var[0]) {
case '$': /* pid */
val = utoa(G.root_pid);
break;
case '!': /* bg pid */
val = G.last_bg_pid ? utoa(G.last_bg_pid) : "";
break;
case '?': /* exitcode */
val = utoa(G.last_exitcode);
break;
case '#': /* argc */
val = utoa(G.global_argc ? G.global_argc-1 : 0);
break;
default:
val = get_local_var_value(var);
}
}
/* Handle any expansions */
if (exp_op == 'L') {
debug_printf_expand("expand: length(%s)=", val);
val = utoa(val ? strlen(val) : 0);
debug_printf_expand("%s\n", val);
} else if (exp_op) {
if (exp_op == '%' || exp_op == '#') {
/* Standard-mandated substring removal ops:
* ${parameter%word} - remove smallest suffix pattern
* ${parameter%%word} - remove largest suffix pattern
* ${parameter#word} - remove smallest prefix pattern
* ${parameter##word} - remove largest prefix pattern
*
* Word is expanded to produce a glob pattern.
* Then var's value is matched to it and matching part removed.
*/
if (val && val[0]) {
char *t;
char *exp_exp_word;
char *loc;
unsigned scan_flags = pick_scan(exp_op, *exp_word);
if (exp_op == *exp_word) /* ## or %% */
exp_word++;
exp_exp_word = encode_then_expand_string(exp_word, /*process_bkslash:*/ 1, /*unbackslash:*/ 1);
if (exp_exp_word)
exp_word = exp_exp_word;
/* HACK ALERT. We depend here on the fact that
* G.global_argv and results of utoa and get_local_var_value
* are actually in writable memory:
* scan_and_match momentarily stores NULs there. */
t = (char*)val;
loc = scan_and_match(t, exp_word, scan_flags);
//bb_error_msg("op:%c str:'%s' pat:'%s' res:'%s'",
// exp_op, t, exp_word, loc);
free(exp_exp_word);
if (loc) { /* match was found */
if (scan_flags & SCAN_MATCH_LEFT_HALF) /* #[#] */
val = loc; /* take right part */
else /* %[%] */
val = to_be_freed = xstrndup(val, loc - val); /* left */
}
}
}
#if ENABLE_HUSH_BASH_COMPAT
else if (exp_op == '/' || exp_op == '\\') {
/* It's ${var/[/]pattern[/repl]} thing.
* Note that in encoded form it has TWO parts:
* var/pattern<SPECIAL_VAR_SYMBOL>repl<SPECIAL_VAR_SYMBOL>
* and if // is used, it is encoded as \:
* var\pattern<SPECIAL_VAR_SYMBOL>repl<SPECIAL_VAR_SYMBOL>
*/
/* Empty variable always gives nothing: */
// "v=''; echo ${v/*/w}" prints "", not "w"
if (val && val[0]) {
/* pattern uses non-standard expansion.
* repl should be unbackslashed and globbed
* by the usual expansion rules:
* >az; >bz;
* v='a bz'; echo "${v/a*z/a*z}" prints "a*z"
* v='a bz'; echo "${v/a*z/\z}" prints "\z"
* v='a bz'; echo ${v/a*z/a*z} prints "az"
* v='a bz'; echo ${v/a*z/\z} prints "z"
* (note that a*z _pattern_ is never globbed!)
*/
char *pattern, *repl, *t;
pattern = encode_then_expand_string(exp_word, /*process_bkslash:*/ 0, /*unbackslash:*/ 0);
if (!pattern)
pattern = xstrdup(exp_word);
debug_printf_varexp("pattern:'%s'->'%s'\n", exp_word, pattern);
*p++ = SPECIAL_VAR_SYMBOL;
exp_word = p;
p = strchr(p, SPECIAL_VAR_SYMBOL);
*p = '\0';
repl = encode_then_expand_string(exp_word, /*process_bkslash:*/ arg0 & 0x80, /*unbackslash:*/ 1);
debug_printf_varexp("repl:'%s'->'%s'\n", exp_word, repl);
/* HACK ALERT. We depend here on the fact that
* G.global_argv and results of utoa and get_local_var_value
* are actually in writable memory:
* replace_pattern momentarily stores NULs there. */
t = (char*)val;
to_be_freed = replace_pattern(t,
pattern,
(repl ? repl : exp_word),
exp_op);
if (to_be_freed) /* at least one replace happened */
val = to_be_freed;
free(pattern);
free(repl);
}
}
#endif
else if (exp_op == ':') {
#if ENABLE_HUSH_BASH_COMPAT && ENABLE_SH_MATH_SUPPORT
/* It's ${var:N[:M]} bashism.
* Note that in encoded form it has TWO parts:
* var:N<SPECIAL_VAR_SYMBOL>M<SPECIAL_VAR_SYMBOL>
*/
arith_t beg, len;
const char *errmsg;
beg = expand_and_evaluate_arith(exp_word, &errmsg);
if (errmsg)
goto arith_err;
debug_printf_varexp("beg:'%s'=%lld\n", exp_word, (long long)beg);
*p++ = SPECIAL_VAR_SYMBOL;
exp_word = p;
p = strchr(p, SPECIAL_VAR_SYMBOL);
*p = '\0';
len = expand_and_evaluate_arith(exp_word, &errmsg);
if (errmsg)
goto arith_err;
debug_printf_varexp("len:'%s'=%lld\n", exp_word, (long long)len);
if (len >= 0) { /* bash compat: len < 0 is illegal */
if (beg < 0) /* bash compat */
beg = 0;
debug_printf_varexp("from val:'%s'\n", val);
if (len == 0 || !val || beg >= strlen(val)) {
arith_err:
val = NULL;
} else {
/* Paranoia. What if user entered 9999999999999
* which fits in arith_t but not int? */
if (len >= INT_MAX)
len = INT_MAX;
val = to_be_freed = xstrndup(val + beg, len);
}
debug_printf_varexp("val:'%s'\n", val);
} else
#endif
{
die_if_script("malformed ${%s:...}", var);
val = NULL;
}
} else { /* one of "-=+?" */
/* Standard-mandated substitution ops:
* ${var?word} - indicate error if unset
* If var is unset, word (or a message indicating it is unset
* if word is null) is written to standard error
* and the shell exits with a non-zero exit status.
* Otherwise, the value of var is substituted.
* ${var-word} - use default value
* If var is unset, word is substituted.
* ${var=word} - assign and use default value
* If var is unset, word is assigned to var.
* In all cases, final value of var is substituted.
* ${var+word} - use alternative value
* If var is unset, null is substituted.
* Otherwise, word is substituted.
*
* Word is subjected to tilde expansion, parameter expansion,
* command substitution, and arithmetic expansion.
* If word is not needed, it is not expanded.
*
* Colon forms (${var:-word}, ${var:=word} etc) do the same,
* but also treat null var as if it is unset.
*/
int use_word = (!val || ((exp_save == ':') && !val[0]));
if (exp_op == '+')
use_word = !use_word;
debug_printf_expand("expand: op:%c (null:%s) test:%i\n", exp_op,
(exp_save == ':') ? "true" : "false", use_word);
if (use_word) {
to_be_freed = encode_then_expand_string(exp_word, /*process_bkslash:*/ 1, /*unbackslash:*/ 1);
if (to_be_freed)
exp_word = to_be_freed;
if (exp_op == '?') {
/* mimic bash message */
die_if_script("%s: %s",
var,
exp_word[0] ? exp_word : "parameter null or not set"
);
//TODO: how interactive bash aborts expansion mid-command?
} else {
val = exp_word;
}
if (exp_op == '=') {
/* ${var=[word]} or ${var:=[word]} */
if (isdigit(var[0]) || var[0] == '#') {
/* mimic bash message */
die_if_script("$%s: cannot assign in this way", var);
val = NULL;
} else {
char *new_var = xasprintf("%s=%s", var, val);
set_local_var(new_var, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
}
}
}
} /* one of "-=+?" */
*exp_saveptr = exp_save;
} /* if (exp_op) */
arg[0] = arg0;
*pp = p;
*to_be_freed_pp = to_be_freed;
return val;
}
/* Expand all variable references in given string, adding words to list[]
* at n, n+1,... positions. Return updated n (so that list[n] is next one
* to be filled). This routine is extremely tricky: has to deal with
* variables/parameters with whitespace, $* and $@, and constructs like
* 'echo -$*-'. If you play here, you must run testsuite afterwards! */
static NOINLINE int expand_vars_to_list(o_string *output, int n, char *arg)
{
/* output->o_expflags & EXP_FLAG_SINGLEWORD (0x80) if we are in
* expansion of right-hand side of assignment == 1-element expand.
*/
char cant_be_null = 0; /* only bit 0x80 matters */
int ended_in_ifs = 0; /* did last unquoted expansion end with IFS chars? */
char *p;
debug_printf_expand("expand_vars_to_list: arg:'%s' singleword:%x\n", arg,
!!(output->o_expflags & EXP_FLAG_SINGLEWORD));
debug_print_list("expand_vars_to_list", output, n);
n = o_save_ptr(output, n);
debug_print_list("expand_vars_to_list[0]", output, n);
while ((p = strchr(arg, SPECIAL_VAR_SYMBOL)) != NULL) {
char first_ch;
char *to_be_freed = NULL;
const char *val = NULL;
#if ENABLE_HUSH_TICK
o_string subst_result = NULL_O_STRING;
#endif
#if ENABLE_SH_MATH_SUPPORT
char arith_buf[sizeof(arith_t)*3 + 2];
#endif
if (ended_in_ifs) {
o_addchr(output, '\0');
n = o_save_ptr(output, n);
ended_in_ifs = 0;
}
o_addblock(output, arg, p - arg);
debug_print_list("expand_vars_to_list[1]", output, n);
arg = ++p;
p = strchr(p, SPECIAL_VAR_SYMBOL);
/* Fetch special var name (if it is indeed one of them)
* and quote bit, force the bit on if singleword expansion -
* important for not getting v=$@ expand to many words. */
first_ch = arg[0] | (output->o_expflags & EXP_FLAG_SINGLEWORD);
/* Is this variable quoted and thus expansion can't be null?
* "$@" is special. Even if quoted, it can still
* expand to nothing (not even an empty string),
* thus it is excluded. */
if ((first_ch & 0x7f) != '@')
cant_be_null |= first_ch;
switch (first_ch & 0x7f) {
/* Highest bit in first_ch indicates that var is double-quoted */
case '*':
case '@': {
int i;
if (!G.global_argv[1])
break;
i = 1;
cant_be_null |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
while (G.global_argv[i]) {
n = expand_on_ifs(NULL, output, n, G.global_argv[i]);
debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, G.global_argc - 1);
if (G.global_argv[i++][0] && G.global_argv[i]) {
/* this argv[] is not empty and not last:
* put terminating NUL, start new word */
o_addchr(output, '\0');
debug_print_list("expand_vars_to_list[2]", output, n);
n = o_save_ptr(output, n);
debug_print_list("expand_vars_to_list[3]", output, n);
}
}
} else
/* If EXP_FLAG_SINGLEWORD, we handle assignment 'a=....$@.....'
* and in this case should treat it like '$*' - see 'else...' below */
if (first_ch == ('@'|0x80) /* quoted $@ */
&& !(output->o_expflags & EXP_FLAG_SINGLEWORD) /* not v="$@" case */
) {
while (1) {
o_addQstr(output, G.global_argv[i]);
if (++i >= G.global_argc)
break;
o_addchr(output, '\0');
debug_print_list("expand_vars_to_list[4]", output, n);
n = o_save_ptr(output, n);
}
} else { /* quoted $* (or v="$@" case): add as one word */
while (1) {
o_addQstr(output, G.global_argv[i]);
if (!G.global_argv[++i])
break;
if (G.ifs[0])
o_addchr(output, G.ifs[0]);
}
output->has_quoted_part = 1;
}
break;
}
case SPECIAL_VAR_SYMBOL: /* <SPECIAL_VAR_SYMBOL><SPECIAL_VAR_SYMBOL> */
/* "Empty variable", used to make "" etc to not disappear */
output->has_quoted_part = 1;
arg++;
cant_be_null = 0x80;
break;
#if ENABLE_HUSH_TICK
case '`': /* <SPECIAL_VAR_SYMBOL>`cmd<SPECIAL_VAR_SYMBOL> */
*p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
arg++;
/* Can't just stuff it into output o_string,
* expanded result may need to be globbed
* and $IFS-splitted */
debug_printf_subst("SUBST '%s' first_ch %x\n", arg, first_ch);
G.last_exitcode = process_command_subs(&subst_result, arg);
debug_printf_subst("SUBST RES:%d '%s'\n", G.last_exitcode, subst_result.data);
val = subst_result.data;
goto store_val;
#endif
#if ENABLE_SH_MATH_SUPPORT
case '+': { /* <SPECIAL_VAR_SYMBOL>+cmd<SPECIAL_VAR_SYMBOL> */
arith_t res;
arg++; /* skip '+' */
*p = '\0'; /* replace trailing <SPECIAL_VAR_SYMBOL> */
debug_printf_subst("ARITH '%s' first_ch %x\n", arg, first_ch);
res = expand_and_evaluate_arith(arg, NULL);
debug_printf_subst("ARITH RES '"ARITH_FMT"'\n", res);
sprintf(arith_buf, ARITH_FMT, res);
val = arith_buf;
break;
}
#endif
default:
val = expand_one_var(&to_be_freed, arg, &p);
IF_HUSH_TICK(store_val:)
if (!(first_ch & 0x80)) { /* unquoted $VAR */
debug_printf_expand("unquoted '%s', output->o_escape:%d\n", val,
!!(output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
if (val && val[0]) {
n = expand_on_ifs(&ended_in_ifs, output, n, val);
val = NULL;
}
} else { /* quoted $VAR, val will be appended below */
output->has_quoted_part = 1;
debug_printf_expand("quoted '%s', output->o_escape:%d\n", val,
!!(output->o_expflags & EXP_FLAG_ESC_GLOB_CHARS));
}
break;
} /* switch (char after <SPECIAL_VAR_SYMBOL>) */
if (val && val[0]) {
o_addQstr(output, val);
}
free(to_be_freed);
/* Restore NULL'ed SPECIAL_VAR_SYMBOL.
* Do the check to avoid writing to a const string. */
if (*p != SPECIAL_VAR_SYMBOL)
*p = SPECIAL_VAR_SYMBOL;
#if ENABLE_HUSH_TICK
o_free(&subst_result);
#endif
arg = ++p;
} /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
if (arg[0]) {
if (ended_in_ifs) {
o_addchr(output, '\0');
n = o_save_ptr(output, n);
}
debug_print_list("expand_vars_to_list[a]", output, n);
/* this part is literal, and it was already pre-quoted
* if needed (much earlier), do not use o_addQstr here! */
o_addstr_with_NUL(output, arg);
debug_print_list("expand_vars_to_list[b]", output, n);
} else if (output->length == o_get_last_ptr(output, n) /* expansion is empty */
&& !(cant_be_null & 0x80) /* and all vars were not quoted. */
) {
n--;
/* allow to reuse list[n] later without re-growth */
output->has_empty_slot = 1;
} else {
o_addchr(output, '\0');
}
return n;
}
static char **expand_variables(char **argv, unsigned expflags)
{
int n;
char **list;
o_string output = NULL_O_STRING;
output.o_expflags = expflags;
n = 0;
while (*argv) {
n = expand_vars_to_list(&output, n, *argv);
argv++;
}
debug_print_list("expand_variables", &output, n);
/* output.data (malloced in one block) gets returned in "list" */
list = o_finalize_list(&output, n);
debug_print_strings("expand_variables[1]", list);
return list;
}
static char **expand_strvec_to_strvec(char **argv)
{
return expand_variables(argv, EXP_FLAG_GLOB | EXP_FLAG_ESC_GLOB_CHARS);
}
#if ENABLE_HUSH_BASH_COMPAT
static char **expand_strvec_to_strvec_singleword_noglob(char **argv)
{
return expand_variables(argv, EXP_FLAG_SINGLEWORD);
}
#endif
/* Used for expansion of right hand of assignments,
* $((...)), heredocs, variable espansion parts.
*
* NB: should NOT do globbing!
* "export v=/bin/c*; env | grep ^v=" outputs "v=/bin/c*"
*/
static char *expand_string_to_string(const char *str, int do_unbackslash)
{
#if !ENABLE_HUSH_BASH_COMPAT
const int do_unbackslash = 1;
#endif
char *argv[2], **list;
debug_printf_expand("string_to_string<='%s'\n", str);
/* This is generally an optimization, but it also
* handles "", which otherwise trips over !list[0] check below.
* (is this ever happens that we actually get str="" here?)
*/
if (!strchr(str, SPECIAL_VAR_SYMBOL) && !strchr(str, '\\')) {
//TODO: Can use on strings with \ too, just unbackslash() them?
debug_printf_expand("string_to_string(fast)=>'%s'\n", str);
return xstrdup(str);
}
argv[0] = (char*)str;
argv[1] = NULL;
list = expand_variables(argv, do_unbackslash
? EXP_FLAG_ESC_GLOB_CHARS | EXP_FLAG_SINGLEWORD
: EXP_FLAG_SINGLEWORD
);
if (HUSH_DEBUG)
if (!list[0] || list[1])
bb_error_msg_and_die("BUG in varexp2");
/* actually, just move string 2*sizeof(char*) bytes back */
overlapping_strcpy((char*)list, list[0]);
if (do_unbackslash)
unbackslash((char*)list);
debug_printf_expand("string_to_string=>'%s'\n", (char*)list);
return (char*)list;
}
/* Used for "eval" builtin */
static char* expand_strvec_to_string(char **argv)
{
char **list;
list = expand_variables(argv, EXP_FLAG_SINGLEWORD);
/* Convert all NULs to spaces */
if (list[0]) {
int n = 1;
while (list[n]) {
if (HUSH_DEBUG)
if (list[n-1] + strlen(list[n-1]) + 1 != list[n])
bb_error_msg_and_die("BUG in varexp3");
/* bash uses ' ' regardless of $IFS contents */
list[n][-1] = ' ';
n++;
}
}
overlapping_strcpy((char*)list, list[0]);
debug_printf_expand("strvec_to_string='%s'\n", (char*)list);
return (char*)list;
}
static char **expand_assignments(char **argv, int count)
{
int i;
char **p;
G.expanded_assignments = p = NULL;
/* Expand assignments into one string each */
for (i = 0; i < count; i++) {
G.expanded_assignments = p = add_string_to_strings(p, expand_string_to_string(argv[i], /*unbackslash:*/ 1));
}
G.expanded_assignments = NULL;
return p;
}
static void switch_off_special_sigs(unsigned mask)
{
unsigned sig = 0;
while ((mask >>= 1) != 0) {
sig++;
if (!(mask & 1))
continue;
if (G.traps) {
if (G.traps[sig] && !G.traps[sig][0])
/* trap is '', has to remain SIG_IGN */
continue;
free(G.traps[sig]);
G.traps[sig] = NULL;
}
/* We are here only if no trap or trap was not '' */
install_sighandler(sig, SIG_DFL);
}
}
#if BB_MMU
/* never called */
void re_execute_shell(char ***to_free, const char *s,
char *g_argv0, char **g_argv,
char **builtin_argv) NORETURN;
static void reset_traps_to_defaults(void)
{
/* This function is always called in a child shell
* after fork (not vfork, NOMMU doesn't use this function).
*/
unsigned sig;
unsigned mask;
/* Child shells are not interactive.
* SIGTTIN/SIGTTOU/SIGTSTP should not have special handling.
* Testcase: (while :; do :; done) + ^Z should background.
* Same goes for SIGTERM, SIGHUP, SIGINT.
*/
mask = (G.special_sig_mask & SPECIAL_INTERACTIVE_SIGS) | G_fatal_sig_mask;
if (!G.traps && !mask)
return; /* already no traps and no special sigs */
/* Switch off special sigs */
switch_off_special_sigs(mask);
#if ENABLE_HUSH_JOB
G_fatal_sig_mask = 0;
#endif
G.special_sig_mask &= ~SPECIAL_INTERACTIVE_SIGS;
/* SIGQUIT,SIGCHLD and maybe SPECIAL_JOBSTOP_SIGS
* remain set in G.special_sig_mask */
if (!G.traps)
return;
/* Reset all sigs to default except ones with empty traps */
for (sig = 0; sig < NSIG; sig++) {
if (!G.traps[sig])
continue; /* no trap: nothing to do */
if (!G.traps[sig][0])
continue; /* empty trap: has to remain SIG_IGN */
/* sig has non-empty trap, reset it: */
free(G.traps[sig]);
G.traps[sig] = NULL;
/* There is no signal for trap 0 (EXIT) */
if (sig == 0)
continue;
install_sighandler(sig, pick_sighandler(sig));
}
}
#else /* !BB_MMU */
static void re_execute_shell(char ***to_free, const char *s,
char *g_argv0, char **g_argv,
char **builtin_argv) NORETURN;
static void re_execute_shell(char ***to_free, const char *s,
char *g_argv0, char **g_argv,
char **builtin_argv)
{
# define NOMMU_HACK_FMT ("-$%x:%x:%x:%x:%x:%llx" IF_HUSH_LOOPS(":%x"))
/* delims + 2 * (number of bytes in printed hex numbers) */
char param_buf[sizeof(NOMMU_HACK_FMT) + 2 * (sizeof(int)*6 + sizeof(long long)*1)];
char *heredoc_argv[4];
struct variable *cur;
# if ENABLE_HUSH_FUNCTIONS
struct function *funcp;
# endif
char **argv, **pp;
unsigned cnt;
unsigned long long empty_trap_mask;
if (!g_argv0) { /* heredoc */
argv = heredoc_argv;
argv[0] = (char *) G.argv0_for_re_execing;
argv[1] = (char *) "-<";
argv[2] = (char *) s;
argv[3] = NULL;
pp = &argv[3]; /* used as pointer to empty environment */
goto do_exec;
}
cnt = 0;
pp = builtin_argv;
if (pp) while (*pp++)
cnt++;
empty_trap_mask = 0;
if (G.traps) {
int sig;
for (sig = 1; sig < NSIG; sig++) {
if (G.traps[sig] && !G.traps[sig][0])
empty_trap_mask |= 1LL << sig;
}
}
sprintf(param_buf, NOMMU_HACK_FMT
, (unsigned) G.root_pid
, (unsigned) G.root_ppid
, (unsigned) G.last_bg_pid
, (unsigned) G.last_exitcode
, cnt
, empty_trap_mask
IF_HUSH_LOOPS(, G.depth_of_loop)
);
# undef NOMMU_HACK_FMT
/* 1:hush 2:-$<pid>:<pid>:<exitcode>:<etc...> <vars...> <funcs...>
* 3:-c 4:<cmd> 5:<arg0> <argN...> 6:NULL
*/
cnt += 6;
for (cur = G.top_var; cur; cur = cur->next) {
if (!cur->flg_export || cur->flg_read_only)
cnt += 2;
}
# if ENABLE_HUSH_FUNCTIONS
for (funcp = G.top_func; funcp; funcp = funcp->next)
cnt += 3;
# endif
pp = g_argv;
while (*pp++)
cnt++;
*to_free = argv = pp = xzalloc(sizeof(argv[0]) * cnt);
*pp++ = (char *) G.argv0_for_re_execing;
*pp++ = param_buf;
for (cur = G.top_var; cur; cur = cur->next) {
if (strcmp(cur->varstr, hush_version_str) == 0)
continue;
if (cur->flg_read_only) {
*pp++ = (char *) "-R";
*pp++ = cur->varstr;
} else if (!cur->flg_export) {
*pp++ = (char *) "-V";
*pp++ = cur->varstr;
}
}
# if ENABLE_HUSH_FUNCTIONS
for (funcp = G.top_func; funcp; funcp = funcp->next) {
*pp++ = (char *) "-F";
*pp++ = funcp->name;
*pp++ = funcp->body_as_string;
}
# endif
/* We can pass activated traps here. Say, -Tnn:trap_string
*
* However, POSIX says that subshells reset signals with traps
* to SIG_DFL.
* I tested bash-3.2 and it not only does that with true subshells
* of the form ( list ), but with any forked children shells.
* I set trap "echo W" WINCH; and then tried:
*
* { echo 1; sleep 20; echo 2; } &
* while true; do echo 1; sleep 20; echo 2; break; done &
* true | { echo 1; sleep 20; echo 2; } | cat
*
* In all these cases sending SIGWINCH to the child shell
* did not run the trap. If I add trap "echo V" WINCH;
* _inside_ group (just before echo 1), it works.
*
* I conclude it means we don't need to pass active traps here.
*/
*pp++ = (char *) "-c";
*pp++ = (char *) s;
if (builtin_argv) {
while (*++builtin_argv)
*pp++ = *builtin_argv;
*pp++ = (char *) "";
}
*pp++ = g_argv0;
while (*g_argv)
*pp++ = *g_argv++;
/* *pp = NULL; - is already there */
pp = environ;
do_exec:
debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
/* Don't propagate SIG_IGN to the child */
if (SPECIAL_JOBSTOP_SIGS != 0)
switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
execve(bb_busybox_exec_path, argv, pp);
/* Fallback. Useful for init=/bin/hush usage etc */
if (argv[0][0] == '/')
execve(argv[0], argv, pp);
xfunc_error_retval = 127;
bb_error_msg_and_die("can't re-execute the shell");
}
#endif /* !BB_MMU */
static int run_and_free_list(struct pipe *pi);
/* Executing from string: eval, sh -c '...'
* or from file: /etc/profile, . file, sh <script>, sh (intereactive)
* end_trigger controls how often we stop parsing
* NUL: parse all, execute, return
* ';': parse till ';' or newline, execute, repeat till EOF
*/
static void parse_and_run_stream(struct in_str *inp, int end_trigger)
{
/* Why we need empty flag?
* An obscure corner case "false; ``; echo $?":
* empty command in `` should still set $? to 0.
* But we can't just set $? to 0 at the start,
* this breaks "false; echo `echo $?`" case.
*/
bool empty = 1;
while (1) {
struct pipe *pipe_list;
#if ENABLE_HUSH_INTERACTIVE
if (end_trigger == ';')
inp->promptmode = 0; /* PS1 */
#endif
pipe_list = parse_stream(NULL, inp, end_trigger);
if (!pipe_list || pipe_list == ERR_PTR) { /* EOF/error */
/* If we are in "big" script
* (not in `cmd` or something similar)...
*/
if (pipe_list == ERR_PTR && end_trigger == ';') {
/* Discard cached input (rest of line) */
int ch = inp->last_char;
while (ch != EOF && ch != '\n') {
//bb_error_msg("Discarded:'%c'", ch);
ch = i_getch(inp);
}
/* Force prompt */
inp->p = NULL;
/* This stream isn't empty */
empty = 0;
continue;
}
if (!pipe_list && empty)
G.last_exitcode = 0;
break;
}
debug_print_tree(pipe_list, 0);
debug_printf_exec("parse_and_run_stream: run_and_free_list\n");
run_and_free_list(pipe_list);
empty = 0;
#if ENABLE_HUSH_FUNCTIONS
if (G.flag_return_in_progress == 1)
break;
#endif
}
}
static void parse_and_run_string(const char *s)
{
struct in_str input;
setup_string_in_str(&input, s);
parse_and_run_stream(&input, '\0');
}
static void parse_and_run_file(FILE *f)
{
struct in_str input;
setup_file_in_str(&input, f);
parse_and_run_stream(&input, ';');
}
#if ENABLE_HUSH_TICK
static FILE *generate_stream_from_string(const char *s, pid_t *pid_p)
{
pid_t pid;
int channel[2];
# if !BB_MMU
char **to_free = NULL;
# endif
xpipe(channel);
pid = BB_MMU ? xfork() : xvfork();
if (pid == 0) { /* child */
disable_restore_tty_pgrp_on_exit();
/* Process substitution is not considered to be usual
* 'command execution'.
* SUSv3 says ctrl-Z should be ignored, ctrl-C should not.
*/
bb_signals(0
+ (1 << SIGTSTP)
+ (1 << SIGTTIN)
+ (1 << SIGTTOU)
, SIG_IGN);
CLEAR_RANDOM_T(&G.random_gen); /* or else $RANDOM repeats in child */
close(channel[0]); /* NB: close _first_, then move fd! */
xmove_fd(channel[1], 1);
/* Prevent it from trying to handle ctrl-z etc */
IF_HUSH_JOB(G.run_list_level = 1;)
/* Awful hack for `trap` or $(trap).
*
* http://www.opengroup.org/onlinepubs/009695399/utilities/trap.html
* contains an example where "trap" is executed in a subshell:
*
* save_traps=$(trap)
* ...
* eval "$save_traps"
*
* Standard does not say that "trap" in subshell shall print
* parent shell's traps. It only says that its output
* must have suitable form, but then, in the above example
* (which is not supposed to be normative), it implies that.
*
* bash (and probably other shell) does implement it
* (traps are reset to defaults, but "trap" still shows them),
* but as a result, "trap" logic is hopelessly messed up:
*
* # trap
* trap -- 'echo Ho' SIGWINCH <--- we have a handler
* # (trap) <--- trap is in subshell - no output (correct, traps are reset)
* # true | trap <--- trap is in subshell - no output (ditto)
* # echo `true | trap` <--- in subshell - output (but traps are reset!)
* trap -- 'echo Ho' SIGWINCH
* # echo `(trap)` <--- in subshell in subshell - output
* trap -- 'echo Ho' SIGWINCH
* # echo `true | (trap)` <--- in subshell in subshell in subshell - output!
* trap -- 'echo Ho' SIGWINCH
*
* The rules when to forget and when to not forget traps
* get really complex and nonsensical.
*
* Our solution: ONLY bare $(trap) or `trap` is special.
*/
s = skip_whitespace(s);
if (strncmp(s, "trap", 4) == 0
&& skip_whitespace(s + 4)[0] == '\0'
) {
static const char *const argv[] = { NULL, NULL };
builtin_trap((char**)argv);
exit(0); /* not _exit() - we need to fflush */
}
# if BB_MMU
reset_traps_to_defaults();
parse_and_run_string(s);
_exit(G.last_exitcode);
# else
/* We re-execute after vfork on NOMMU. This makes this script safe:
* yes "0123456789012345678901234567890" | dd bs=32 count=64k >BIG
* huge=`cat BIG` # was blocking here forever
* echo OK
*/
re_execute_shell(&to_free,
s,
G.global_argv[0],
G.global_argv + 1,
NULL);
# endif
}
/* parent */
*pid_p = pid;
# if ENABLE_HUSH_FAST
G.count_SIGCHLD++;
//bb_error_msg("[%d] fork in generate_stream_from_string:"
// " G.count_SIGCHLD:%d G.handled_SIGCHLD:%d",
// getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
# endif
enable_restore_tty_pgrp_on_exit();
# if !BB_MMU
free(to_free);
# endif
close(channel[1]);
close_on_exec_on(channel[0]);
return xfdopen_for_read(channel[0]);
}
/* Return code is exit status of the process that is run. */
static int process_command_subs(o_string *dest, const char *s)
{
FILE *fp;
struct in_str pipe_str;
pid_t pid;
int status, ch, eol_cnt;
fp = generate_stream_from_string(s, &pid);
/* Now send results of command back into original context */
setup_file_in_str(&pipe_str, fp);
eol_cnt = 0;
while ((ch = i_getch(&pipe_str)) != EOF) {
if (ch == '\n') {
eol_cnt++;
continue;
}
while (eol_cnt) {
o_addchr(dest, '\n');
eol_cnt--;
}
o_addQchr(dest, ch);
}
debug_printf("done reading from `cmd` pipe, closing it\n");
fclose(fp);
/* We need to extract exitcode. Test case
* "true; echo `sleep 1; false` $?"
* should print 1 */
safe_waitpid(pid, &status, 0);
debug_printf("child exited. returning its exitcode:%d\n", WEXITSTATUS(status));
return WEXITSTATUS(status);
}
#endif /* ENABLE_HUSH_TICK */
static void setup_heredoc(struct redir_struct *redir)
{
struct fd_pair pair;
pid_t pid;
int len, written;
/* the _body_ of heredoc (misleading field name) */
const char *heredoc = redir->rd_filename;
char *expanded;
#if !BB_MMU
char **to_free;
#endif
expanded = NULL;
if (!(redir->rd_dup & HEREDOC_QUOTED)) {
expanded = encode_then_expand_string(heredoc, /*process_bkslash:*/ 1, /*unbackslash:*/ 1);
if (expanded)
heredoc = expanded;
}
len = strlen(heredoc);
close(redir->rd_fd); /* often saves dup2+close in xmove_fd */
xpiped_pair(pair);
xmove_fd(pair.rd, redir->rd_fd);
/* Try writing without forking. Newer kernels have
* dynamically growing pipes. Must use non-blocking write! */
ndelay_on(pair.wr);
while (1) {
written = write(pair.wr, heredoc, len);
if (written <= 0)
break;
len -= written;
if (len == 0) {
close(pair.wr);
free(expanded);
return;
}
heredoc += written;
}
ndelay_off(pair.wr);
/* Okay, pipe buffer was not big enough */
/* Note: we must not create a stray child (bastard? :)
* for the unsuspecting parent process. Child creates a grandchild
* and exits before parent execs the process which consumes heredoc
* (that exec happens after we return from this function) */
#if !BB_MMU
to_free = NULL;
#endif
pid = xvfork();
if (pid == 0) {
/* child */
disable_restore_tty_pgrp_on_exit();
pid = BB_MMU ? xfork() : xvfork();
if (pid != 0)
_exit(0);
/* grandchild */
close(redir->rd_fd); /* read side of the pipe */
#if BB_MMU
full_write(pair.wr, heredoc, len); /* may loop or block */
_exit(0);
#else
/* Delegate blocking writes to another process */
xmove_fd(pair.wr, STDOUT_FILENO);
re_execute_shell(&to_free, heredoc, NULL, NULL, NULL);
#endif
}
/* parent */
#if ENABLE_HUSH_FAST
G.count_SIGCHLD++;
//bb_error_msg("[%d] fork in setup_heredoc: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
#endif
enable_restore_tty_pgrp_on_exit();
#if !BB_MMU
free(to_free);
#endif
close(pair.wr);
free(expanded);
wait(NULL); /* wait till child has died */
}
/* squirrel != NULL means we squirrel away copies of stdin, stdout,
* and stderr if they are redirected. */
static int setup_redirects(struct command *prog, int squirrel[])
{
int openfd, mode;
struct redir_struct *redir;
for (redir = prog->redirects; redir; redir = redir->next) {
if (redir->rd_type == REDIRECT_HEREDOC2) {
/* rd_fd<<HERE case */
if (squirrel && redir->rd_fd < 3
&& squirrel[redir->rd_fd] < 0
) {
squirrel[redir->rd_fd] = dup(redir->rd_fd);
}
/* for REDIRECT_HEREDOC2, rd_filename holds _contents_
* of the heredoc */
debug_printf_parse("set heredoc '%s'\n",
redir->rd_filename);
setup_heredoc(redir);
continue;
}
if (redir->rd_dup == REDIRFD_TO_FILE) {
/* rd_fd<*>file case (<*> is <,>,>>,<>) */
char *p;
if (redir->rd_filename == NULL) {
/* Something went wrong in the parse.
* Pretend it didn't happen */
bb_error_msg("bug in redirect parse");
continue;
}
mode = redir_table[redir->rd_type].mode;
p = expand_string_to_string(redir->rd_filename, /*unbackslash:*/ 1);
openfd = open_or_warn(p, mode);
free(p);
if (openfd < 0) {
/* this could get lost if stderr has been redirected, but
* bash and ash both lose it as well (though zsh doesn't!) */
//what the above comment tries to say?
return 1;
}
} else {
/* rd_fd<*>rd_dup or rd_fd<*>- cases */
openfd = redir->rd_dup;
}
if (openfd != redir->rd_fd) {
if (squirrel && redir->rd_fd < 3
&& squirrel[redir->rd_fd] < 0
) {
squirrel[redir->rd_fd] = dup(redir->rd_fd);
}
if (openfd == REDIRFD_CLOSE) {
/* "n>-" means "close me" */
close(redir->rd_fd);
} else {
xdup2(openfd, redir->rd_fd);
if (redir->rd_dup == REDIRFD_TO_FILE)
close(openfd);
}
}
}
return 0;
}
static void restore_redirects(int squirrel[])
{
int i, fd;
for (i = 0; i < 3; i++) {
fd = squirrel[i];
if (fd != -1) {
/* We simply die on error */
xmove_fd(fd, i);
}
}
}
static char *find_in_path(const char *arg)
{
char *ret = NULL;
const char *PATH = get_local_var_value("PATH");
if (!PATH)
return NULL;
while (1) {
const char *end = strchrnul(PATH, ':');
int sz = end - PATH; /* must be int! */
free(ret);
if (sz != 0) {
ret = xasprintf("%.*s/%s", sz, PATH, arg);
} else {
/* We have xxx::yyyy in $PATH,
* it means "use current dir" */
ret = xstrdup(arg);
}
if (access(ret, F_OK) == 0)
break;
if (*end == '\0') {
free(ret);
return NULL;
}
PATH = end + 1;
}
return ret;
}
static const struct built_in_command *find_builtin_helper(const char *name,
const struct built_in_command *x,
const struct built_in_command *end)
{
while (x != end) {
if (strcmp(name, x->b_cmd) != 0) {
x++;
continue;
}
debug_printf_exec("found builtin '%s'\n", name);
return x;
}
return NULL;
}
static const struct built_in_command *find_builtin1(const char *name)
{
return find_builtin_helper(name, bltins1, &bltins1[ARRAY_SIZE(bltins1)]);
}
static const struct built_in_command *find_builtin(const char *name)
{
const struct built_in_command *x = find_builtin1(name);
if (x)
return x;
return find_builtin_helper(name, bltins2, &bltins2[ARRAY_SIZE(bltins2)]);
}
#if ENABLE_HUSH_FUNCTIONS
static struct function **find_function_slot(const char *name)
{
struct function **funcpp = &G.top_func;
while (*funcpp) {
if (strcmp(name, (*funcpp)->name) == 0) {
break;
}
funcpp = &(*funcpp)->next;
}
return funcpp;
}
static const struct function *find_function(const char *name)
{
const struct function *funcp = *find_function_slot(name);
if (funcp)
debug_printf_exec("found function '%s'\n", name);
return funcp;
}
/* Note: takes ownership on name ptr */
static struct function *new_function(char *name)
{
struct function **funcpp = find_function_slot(name);
struct function *funcp = *funcpp;
if (funcp != NULL) {
struct command *cmd = funcp->parent_cmd;
debug_printf_exec("func %p parent_cmd %p\n", funcp, cmd);
if (!cmd) {
debug_printf_exec("freeing & replacing function '%s'\n", funcp->name);
free(funcp->name);
/* Note: if !funcp->body, do not free body_as_string!
* This is a special case of "-F name body" function:
* body_as_string was not malloced! */
if (funcp->body) {
free_pipe_list(funcp->body);
# if !BB_MMU
free(funcp->body_as_string);
# endif
}
} else {
debug_printf_exec("reinserting in tree & replacing function '%s'\n", funcp->name);
cmd->argv[0] = funcp->name;
cmd->group = funcp->body;
# if !BB_MMU
cmd->group_as_string = funcp->body_as_string;
# endif
}
} else {
debug_printf_exec("remembering new function '%s'\n", name);
funcp = *funcpp = xzalloc(sizeof(*funcp));
/*funcp->next = NULL;*/
}
funcp->name = name;
return funcp;
}
static void unset_func(const char *name)
{
struct function **funcpp = find_function_slot(name);
struct function *funcp = *funcpp;
if (funcp != NULL) {
debug_printf_exec("freeing function '%s'\n", funcp->name);
*funcpp = funcp->next;
/* funcp is unlinked now, deleting it.
* Note: if !funcp->body, the function was created by
* "-F name body", do not free ->body_as_string
* and ->name as they were not malloced. */
if (funcp->body) {
free_pipe_list(funcp->body);
free(funcp->name);
# if !BB_MMU
free(funcp->body_as_string);
# endif
}
free(funcp);
}
}
# if BB_MMU
#define exec_function(to_free, funcp, argv) \
exec_function(funcp, argv)
# endif
static void exec_function(char ***to_free,
const struct function *funcp,
char **argv) NORETURN;
static void exec_function(char ***to_free,
const struct function *funcp,
char **argv)
{
# if BB_MMU
int n = 1;
argv[0] = G.global_argv[0];
G.global_argv = argv;
while (*++argv)
n++;
G.global_argc = n;
/* On MMU, funcp->body is always non-NULL */
n = run_list(funcp->body);
fflush_all();
_exit(n);
# else
re_execute_shell(to_free,
funcp->body_as_string,
G.global_argv[0],
argv + 1,
NULL);
# endif
}
static int run_function(const struct function *funcp, char **argv)
{
int rc;
save_arg_t sv;
smallint sv_flg;
save_and_replace_G_args(&sv, argv);
/* "we are in function, ok to use return" */
sv_flg = G.flag_return_in_progress;
G.flag_return_in_progress = -1;
# if ENABLE_HUSH_LOCAL
G.func_nest_level++;
# endif
/* On MMU, funcp->body is always non-NULL */
# if !BB_MMU
if (!funcp->body) {
/* Function defined by -F */
parse_and_run_string(funcp->body_as_string);
rc = G.last_exitcode;
} else
# endif
{
rc = run_list(funcp->body);
}
# if ENABLE_HUSH_LOCAL
{
struct variable *var;
struct variable **var_pp;
var_pp = &G.top_var;
while ((var = *var_pp) != NULL) {
if (var->func_nest_level < G.func_nest_level) {
var_pp = &var->next;
continue;
}
/* Unexport */
if (var->flg_export)
bb_unsetenv(var->varstr);
/* Remove from global list */
*var_pp = var->next;
/* Free */
if (!var->max_len)
free(var->varstr);
free(var);
}
G.func_nest_level--;
}
# endif
G.flag_return_in_progress = sv_flg;
restore_G_args(&sv, argv);
return rc;
}
#endif /* ENABLE_HUSH_FUNCTIONS */
#if BB_MMU
#define exec_builtin(to_free, x, argv) \
exec_builtin(x, argv)
#else
#define exec_builtin(to_free, x, argv) \
exec_builtin(to_free, argv)
#endif
static void exec_builtin(char ***to_free,
const struct built_in_command *x,
char **argv) NORETURN;
static void exec_builtin(char ***to_free,
const struct built_in_command *x,
char **argv)
{
#if BB_MMU
int rcode;
fflush_all();
rcode = x->b_function(argv);
fflush_all();
_exit(rcode);
#else
fflush_all();
/* On NOMMU, we must never block!
* Example: { sleep 99 | read line; } & echo Ok
*/
re_execute_shell(to_free,
argv[0],
G.global_argv[0],
G.global_argv + 1,
argv);
#endif
}
static void execvp_or_die(char **argv) NORETURN;
static void execvp_or_die(char **argv)
{
debug_printf_exec("execing '%s'\n", argv[0]);
/* Don't propagate SIG_IGN to the child */
if (SPECIAL_JOBSTOP_SIGS != 0)
switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
execvp(argv[0], argv);
bb_perror_msg("can't execute '%s'", argv[0]);
_exit(127); /* bash compat */
}
#if ENABLE_HUSH_MODE_X
static void dump_cmd_in_x_mode(char **argv)
{
if (G_x_mode && argv) {
/* We want to output the line in one write op */
char *buf, *p;
int len;
int n;
len = 3;
n = 0;
while (argv[n])
len += strlen(argv[n++]) + 1;
buf = xmalloc(len);
buf[0] = '+';
p = buf + 1;
n = 0;
while (argv[n])
p += sprintf(p, " %s", argv[n++]);
*p++ = '\n';
*p = '\0';
fputs(buf, stderr);
free(buf);
}
}
#else
# define dump_cmd_in_x_mode(argv) ((void)0)
#endif
#if BB_MMU
#define pseudo_exec_argv(nommu_save, argv, assignment_cnt, argv_expanded) \
pseudo_exec_argv(argv, assignment_cnt, argv_expanded)
#define pseudo_exec(nommu_save, command, argv_expanded) \
pseudo_exec(command, argv_expanded)
#endif
/* Called after [v]fork() in run_pipe, or from builtin_exec.
* Never returns.
* Don't exit() here. If you don't exec, use _exit instead.
* The at_exit handlers apparently confuse the calling process,
* in particular stdin handling. Not sure why? -- because of vfork! (vda) */
static void pseudo_exec_argv(nommu_save_t *nommu_save,
char **argv, int assignment_cnt,
char **argv_expanded) NORETURN;
static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
char **argv, int assignment_cnt,
char **argv_expanded)
{
char **new_env;
new_env = expand_assignments(argv, assignment_cnt);
dump_cmd_in_x_mode(new_env);
if (!argv[assignment_cnt]) {
/* Case when we are here: ... | var=val | ...
* (note that we do not exit early, i.e., do not optimize out
* expand_assignments(): think about ... | var=`sleep 1` | ...
*/
free_strings(new_env);
_exit(EXIT_SUCCESS);
}
#if BB_MMU
set_vars_and_save_old(new_env);
free(new_env); /* optional */
/* we can also destroy set_vars_and_save_old's return value,
* to save memory */
#else
nommu_save->new_env = new_env;
nommu_save->old_vars = set_vars_and_save_old(new_env);
#endif
if (argv_expanded) {
argv = argv_expanded;
} else {
argv = expand_strvec_to_strvec(argv + assignment_cnt);
#if !BB_MMU
nommu_save->argv = argv;
#endif
}
dump_cmd_in_x_mode(argv);
#if ENABLE_FEATURE_SH_STANDALONE || BB_MMU
if (strchr(argv[0], '/') != NULL)
goto skip;
#endif
/* Check if the command matches any of the builtins.
* Depending on context, this might be redundant. But it's
* easier to waste a few CPU cycles than it is to figure out
* if this is one of those cases.
*/
{
/* On NOMMU, it is more expensive to re-execute shell
* just in order to run echo or test builtin.
* It's better to skip it here and run corresponding
* non-builtin later. */
const struct built_in_command *x;
x = BB_MMU ? find_builtin(argv[0]) : find_builtin1(argv[0]);
if (x) {
exec_builtin(&nommu_save->argv_from_re_execing, x, argv);
}
}
#if ENABLE_HUSH_FUNCTIONS
/* Check if the command matches any functions */
{
const struct function *funcp = find_function(argv[0]);
if (funcp) {
exec_function(&nommu_save->argv_from_re_execing, funcp, argv);
}
}
#endif
#if ENABLE_FEATURE_SH_STANDALONE
/* Check if the command matches any busybox applets */
{
int a = find_applet_by_name(argv[0]);
if (a >= 0) {
# if BB_MMU /* see above why on NOMMU it is not allowed */
if (APPLET_IS_NOEXEC(a)) {
debug_printf_exec("running applet '%s'\n", argv[0]);
run_applet_no_and_exit(a, argv);
}
# endif
/* Re-exec ourselves */
debug_printf_exec("re-execing applet '%s'\n", argv[0]);
/* Don't propagate SIG_IGN to the child */
if (SPECIAL_JOBSTOP_SIGS != 0)
switch_off_special_sigs(G.special_sig_mask & SPECIAL_JOBSTOP_SIGS);
execv(bb_busybox_exec_path, argv);
/* If they called chroot or otherwise made the binary no longer
* executable, fall through */
}
}
#endif
#if ENABLE_FEATURE_SH_STANDALONE || BB_MMU
skip:
#endif
execvp_or_die(argv);
}
/* Called after [v]fork() in run_pipe
*/
static void pseudo_exec(nommu_save_t *nommu_save,
struct command *command,
char **argv_expanded) NORETURN;
static void pseudo_exec(nommu_save_t *nommu_save,
struct command *command,
char **argv_expanded)
{
if (command->argv) {
pseudo_exec_argv(nommu_save, command->argv,
command->assignment_cnt, argv_expanded);
}
if (command->group) {
/* Cases when we are here:
* ( list )
* { list } &
* ... | ( list ) | ...
* ... | { list } | ...
*/
#if BB_MMU
int rcode;
debug_printf_exec("pseudo_exec: run_list\n");
reset_traps_to_defaults();
rcode = run_list(command->group);
/* OK to leak memory by not calling free_pipe_list,
* since this process is about to exit */
_exit(rcode);
#else
re_execute_shell(&nommu_save->argv_from_re_execing,
command->group_as_string,
G.global_argv[0],
G.global_argv + 1,
NULL);
#endif
}
/* Case when we are here: ... | >file */
debug_printf_exec("pseudo_exec'ed null command\n");
_exit(EXIT_SUCCESS);
}
#if ENABLE_HUSH_JOB
static const char *get_cmdtext(struct pipe *pi)
{
char **argv;
char *p;
int len;
/* This is subtle. ->cmdtext is created only on first backgrounding.
* (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...)
* On subsequent bg argv is trashed, but we won't use it */
if (pi->cmdtext)
return pi->cmdtext;
argv = pi->cmds[0].argv;
if (!argv || !argv[0]) {
pi->cmdtext = xzalloc(1);
return pi->cmdtext;
}
len = 0;
do {
len += strlen(*argv) + 1;
} while (*++argv);
p = xmalloc(len);
pi->cmdtext = p;
argv = pi->cmds[0].argv;
do {
len = strlen(*argv);
memcpy(p, *argv, len);
p += len;
*p++ = ' ';
} while (*++argv);
p[-1] = '\0';
return pi->cmdtext;
}
static void insert_bg_job(struct pipe *pi)
{
struct pipe *job, **jobp;
int i;
/* Linear search for the ID of the job to use */
pi->jobid = 1;
for (job = G.job_list; job; job = job->next)
if (job->jobid >= pi->jobid)
pi->jobid = job->jobid + 1;
/* Add job to the list of running jobs */
jobp = &G.job_list;
while ((job = *jobp) != NULL)
jobp = &job->next;
job = *jobp = xmalloc(sizeof(*job));
*job = *pi; /* physical copy */
job->next = NULL;
job->cmds = xzalloc(sizeof(pi->cmds[0]) * pi->num_cmds);
/* Cannot copy entire pi->cmds[] vector! This causes double frees */
for (i = 0; i < pi->num_cmds; i++) {
job->cmds[i].pid = pi->cmds[i].pid;
/* all other fields are not used and stay zero */
}
job->cmdtext = xstrdup(get_cmdtext(pi));
if (G_interactive_fd)
printf("[%d] %d %s\n", job->jobid, job->cmds[0].pid, job->cmdtext);
G.last_jobid = job->jobid;
}
static void remove_bg_job(struct pipe *pi)
{
struct pipe *prev_pipe;
if (pi == G.job_list) {
G.job_list = pi->next;
} else {
prev_pipe = G.job_list;
while (prev_pipe->next != pi)
prev_pipe = prev_pipe->next;
prev_pipe->next = pi->next;
}
if (G.job_list)
G.last_jobid = G.job_list->jobid;
else
G.last_jobid = 0;
}
/* Remove a backgrounded job */
static void delete_finished_bg_job(struct pipe *pi)
{
remove_bg_job(pi);
free_pipe(pi);
}
#endif /* JOB */
/* Check to see if any processes have exited -- if they
* have, figure out why and see if a job has completed */
static int checkjobs(struct pipe *fg_pipe)
{
int attributes;
int status;
#if ENABLE_HUSH_JOB
struct pipe *pi;
#endif
pid_t childpid;
int rcode = 0;
debug_printf_jobs("checkjobs %p\n", fg_pipe);
attributes = WUNTRACED;
if (fg_pipe == NULL)
attributes |= WNOHANG;
errno = 0;
#if ENABLE_HUSH_FAST
if (G.handled_SIGCHLD == G.count_SIGCHLD) {
//bb_error_msg("[%d] checkjobs: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d children?:%d fg_pipe:%p",
//getpid(), G.count_SIGCHLD, G.handled_SIGCHLD, G.we_have_children, fg_pipe);
/* There was neither fork nor SIGCHLD since last waitpid */
/* Avoid doing waitpid syscall if possible */
if (!G.we_have_children) {
errno = ECHILD;
return -1;
}
if (fg_pipe == NULL) { /* is WNOHANG set? */
/* We have children, but they did not exit
* or stop yet (we saw no SIGCHLD) */
return 0;
}
/* else: !WNOHANG, waitpid will block, can't short-circuit */
}
#endif
/* Do we do this right?
* bash-3.00# sleep 20 | false
* <ctrl-Z pressed>
* [3]+ Stopped sleep 20 | false
* bash-3.00# echo $?
* 1 <========== bg pipe is not fully done, but exitcode is already known!
* [hush 1.14.0: yes we do it right]
*/
wait_more:
while (1) {
int i;
int dead;
#if ENABLE_HUSH_FAST
i = G.count_SIGCHLD;
#endif
childpid = waitpid(-1, &status, attributes);
if (childpid <= 0) {
if (childpid && errno != ECHILD)
bb_perror_msg("waitpid");
#if ENABLE_HUSH_FAST
else { /* Until next SIGCHLD, waitpid's are useless */
G.we_have_children = (childpid == 0);
G.handled_SIGCHLD = i;
//bb_error_msg("[%d] checkjobs: waitpid returned <= 0, G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
}
#endif
break;
}
dead = WIFEXITED(status) || WIFSIGNALED(status);
#if DEBUG_JOBS
if (WIFSTOPPED(status))
debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n",
childpid, WSTOPSIG(status), WEXITSTATUS(status));
if (WIFSIGNALED(status))
debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n",
childpid, WTERMSIG(status), WEXITSTATUS(status));
if (WIFEXITED(status))
debug_printf_jobs("pid %d exited, exitcode %d\n",
childpid, WEXITSTATUS(status));
#endif
/* Were we asked to wait for fg pipe? */
if (fg_pipe) {
i = fg_pipe->num_cmds;
while (--i >= 0) {
debug_printf_jobs("check pid %d\n", fg_pipe->cmds[i].pid);
if (fg_pipe->cmds[i].pid != childpid)
continue;
if (dead) {
int ex;
fg_pipe->cmds[i].pid = 0;
fg_pipe->alive_cmds--;
ex = WEXITSTATUS(status);
/* bash prints killer signal's name for *last*
* process in pipe (prints just newline for SIGINT/SIGPIPE).
* Mimic this. Example: "sleep 5" + (^\ or kill -QUIT)
*/
if (WIFSIGNALED(status)) {
int sig = WTERMSIG(status);
if (i == fg_pipe->num_cmds-1)
/* TODO: use strsignal() instead for bash compat? but that's bloat... */
printf("%s\n", sig == SIGINT || sig == SIGPIPE ? "" : get_signame(sig));
/* TODO: if (WCOREDUMP(status)) + " (core dumped)"; */
/* TODO: MIPS has 128 sigs (1..128), what if sig==128 here?
* Maybe we need to use sig | 128? */
ex = sig + 128;
}
fg_pipe->cmds[i].cmd_exitcode = ex;
} else {
fg_pipe->cmds[i].is_stopped = 1;
fg_pipe->stopped_cmds++;
}
debug_printf_jobs("fg_pipe: alive_cmds %d stopped_cmds %d\n",
fg_pipe->alive_cmds, fg_pipe->stopped_cmds);
if (fg_pipe->alive_cmds == fg_pipe->stopped_cmds) {
/* All processes in fg pipe have exited or stopped */
i = fg_pipe->num_cmds;
while (--i >= 0) {
rcode = fg_pipe->cmds[i].cmd_exitcode;
/* usually last process gives overall exitstatus,
* but with "set -o pipefail", last *failed* process does */
if (G.o_opt[OPT_O_PIPEFAIL] == 0 || rcode != 0)
break;
}
IF_HAS_KEYWORDS(if (fg_pipe->pi_inverted) rcode = !rcode;)
/* Note: *non-interactive* bash does not continue if all processes in fg pipe
* are stopped. Testcase: "cat | cat" in a script (not on command line!)
* and "killall -STOP cat" */
if (G_interactive_fd) {
#if ENABLE_HUSH_JOB
if (fg_pipe->alive_cmds != 0)
insert_bg_job(fg_pipe);
#endif
return rcode;
}
if (fg_pipe->alive_cmds == 0)
return rcode;
}
/* There are still running processes in the fg pipe */
goto wait_more; /* do waitpid again */
}
/* it wasnt fg_pipe, look for process in bg pipes */
}
#if ENABLE_HUSH_JOB
/* We asked to wait for bg or orphaned children */
/* No need to remember exitcode in this case */
for (pi = G.job_list; pi; pi = pi->next) {
for (i = 0; i < pi->num_cmds; i++) {
if (pi->cmds[i].pid == childpid)
goto found_pi_and_prognum;
}
}
/* Happens when shell is used as init process (init=/bin/sh) */
debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
continue; /* do waitpid again */
found_pi_and_prognum:
if (dead) {
/* child exited */
pi->cmds[i].pid = 0;
pi->alive_cmds--;
if (!pi->alive_cmds) {
if (G_interactive_fd)
printf(JOB_STATUS_FORMAT, pi->jobid,
"Done", pi->cmdtext);
delete_finished_bg_job(pi);
}
} else {
/* child stopped */
pi->cmds[i].is_stopped = 1;
pi->stopped_cmds++;
}
#endif
} /* while (waitpid succeeds)... */
return rcode;
}
#if ENABLE_HUSH_JOB
static int checkjobs_and_fg_shell(struct pipe *fg_pipe)
{
pid_t p;
int rcode = checkjobs(fg_pipe);
if (G_saved_tty_pgrp) {
/* Job finished, move the shell to the foreground */
p = getpgrp(); /* our process group id */
debug_printf_jobs("fg'ing ourself: getpgrp()=%d\n", (int)p);
tcsetpgrp(G_interactive_fd, p);
}
return rcode;
}
#endif
/* Start all the jobs, but don't wait for anything to finish.
* See checkjobs().
*
* Return code is normally -1, when the caller has to wait for children
* to finish to determine the exit status of the pipe. If the pipe
* is a simple builtin command, however, the action is done by the
* time run_pipe returns, and the exit code is provided as the
* return value.
*
* Returns -1 only if started some children. IOW: we have to
* mask out retvals of builtins etc with 0xff!
*
* The only case when we do not need to [v]fork is when the pipe
* is single, non-backgrounded, non-subshell command. Examples:
* cmd ; ... { list } ; ...
* cmd && ... { list } && ...
* cmd || ... { list } || ...
* If it is, then we can run cmd as a builtin, NOFORK,
* or (if SH_STANDALONE) an applet, and we can run the { list }
* with run_list. If it isn't one of these, we fork and exec cmd.
*
* Cases when we must fork:
* non-single: cmd | cmd
* backgrounded: cmd & { list } &
* subshell: ( list ) [&]
*/
#if !ENABLE_HUSH_MODE_X
#define redirect_and_varexp_helper(new_env_p, old_vars_p, command, squirrel, argv_expanded) \
redirect_and_varexp_helper(new_env_p, old_vars_p, command, squirrel)
#endif
static int redirect_and_varexp_helper(char ***new_env_p,
struct variable **old_vars_p,
struct command *command,
int squirrel[3],
char **argv_expanded)
{
/* setup_redirects acts on file descriptors, not FILEs.
* This is perfect for work that comes after exec().
* Is it really safe for inline use? Experimentally,
* things seem to work. */
int rcode = setup_redirects(command, squirrel);
if (rcode == 0) {
char **new_env = expand_assignments(command->argv, command->assignment_cnt);
*new_env_p = new_env;
dump_cmd_in_x_mode(new_env);
dump_cmd_in_x_mode(argv_expanded);
if (old_vars_p)
*old_vars_p = set_vars_and_save_old(new_env);
}
return rcode;
}
static NOINLINE int run_pipe(struct pipe *pi)
{
static const char *const null_ptr = NULL;
int cmd_no;
int next_infd;
struct command *command;
char **argv_expanded;
char **argv;
/* it is not always needed, but we aim to smaller code */
int squirrel[] = { -1, -1, -1 };
int rcode;
debug_printf_exec("run_pipe start: members:%d\n", pi->num_cmds);
debug_enter();
/* Testcase: set -- q w e; (IFS='' echo "$*"; IFS=''; echo "$*"); echo "$*"
* Result should be 3 lines: q w e, qwe, q w e
*/
G.ifs = get_local_var_value("IFS");
if (!G.ifs)
G.ifs = defifs;
IF_HUSH_JOB(pi->pgrp = -1;)
pi->stopped_cmds = 0;
command = &pi->cmds[0];
argv_expanded = NULL;
if (pi->num_cmds != 1
|| pi->followup == PIPE_BG
|| command->cmd_type == CMD_SUBSHELL
) {
goto must_fork;
}
pi->alive_cmds = 1;
debug_printf_exec(": group:%p argv:'%s'\n",
command->group, command->argv ? command->argv[0] : "NONE");
if (command->group) {
#if ENABLE_HUSH_FUNCTIONS
if (command->cmd_type == CMD_FUNCDEF) {
/* "executing" func () { list } */
struct function *funcp;
funcp = new_function(command->argv[0]);
/* funcp->name is already set to argv[0] */
funcp->body = command->group;
# if !BB_MMU
funcp->body_as_string = command->group_as_string;
command->group_as_string = NULL;
# endif
command->group = NULL;
command->argv[0] = NULL;
debug_printf_exec("cmd %p has child func at %p\n", command, funcp);
funcp->parent_cmd = command;
command->child_func = funcp;
debug_printf_exec("run_pipe: return EXIT_SUCCESS\n");
debug_leave();
return EXIT_SUCCESS;
}
#endif
/* { list } */
debug_printf("non-subshell group\n");
rcode = 1; /* exitcode if redir failed */
if (setup_redirects(command, squirrel) == 0) {
debug_printf_exec(": run_list\n");
rcode = run_list(command->group) & 0xff;
}
restore_redirects(squirrel);
IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
debug_leave();
debug_printf_exec("run_pipe: return %d\n", rcode);
return rcode;
}
argv = command->argv ? command->argv : (char **) &null_ptr;
{
const struct built_in_command *x;
#if ENABLE_HUSH_FUNCTIONS
const struct function *funcp;
#else
enum { funcp = 0 };
#endif
char **new_env = NULL;
struct variable *old_vars = NULL;
if (argv[command->assignment_cnt] == NULL) {
/* Assignments, but no command */
/* Ensure redirects take effect (that is, create files).
* Try "a=t >file" */
#if 0 /* A few cases in testsuite fail with this code. FIXME */
rcode = redirect_and_varexp_helper(&new_env, /*old_vars:*/ NULL, command, squirrel, /*argv_expanded:*/ NULL);
/* Set shell variables */
if (new_env) {
argv = new_env;
while (*argv) {
set_local_var(*argv, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
/* Do we need to flag set_local_var() errors?
* "assignment to readonly var" and "putenv error"
*/
argv++;
}
}
/* Redirect error sets $? to 1. Otherwise,
* if evaluating assignment value set $?, retain it.
* Try "false; q=`exit 2`; echo $?" - should print 2: */
if (rcode == 0)
rcode = G.last_exitcode;
/* Exit, _skipping_ variable restoring code: */
goto clean_up_and_ret0;
#else /* Older, bigger, but more correct code */
rcode = setup_redirects(command, squirrel);
restore_redirects(squirrel);
/* Set shell variables */
if (G_x_mode)
bb_putchar_stderr('+');
while (*argv) {
char *p = expand_string_to_string(*argv, /*unbackslash:*/ 1);
if (G_x_mode)
fprintf(stderr, " %s", p);
debug_printf_exec("set shell var:'%s'->'%s'\n",
*argv, p);
set_local_var(p, /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
/* Do we need to flag set_local_var() errors?
* "assignment to readonly var" and "putenv error"
*/
argv++;
}
if (G_x_mode)
bb_putchar_stderr('\n');
/* Redirect error sets $? to 1. Otherwise,
* if evaluating assignment value set $?, retain it.
* Try "false; q=`exit 2`; echo $?" - should print 2: */
if (rcode == 0)
rcode = G.last_exitcode;
IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
debug_leave();
debug_printf_exec("run_pipe: return %d\n", rcode);
return rcode;
#endif
}
/* Expand the rest into (possibly) many strings each */
#if ENABLE_HUSH_BASH_COMPAT
if (command->cmd_type == CMD_SINGLEWORD_NOGLOB) {
argv_expanded = expand_strvec_to_strvec_singleword_noglob(argv + command->assignment_cnt);
} else
#endif
{
argv_expanded = expand_strvec_to_strvec(argv + command->assignment_cnt);
}
/* if someone gives us an empty string: `cmd with empty output` */
if (!argv_expanded[0]) {
free(argv_expanded);
debug_leave();
return G.last_exitcode;
}
x = find_builtin(argv_expanded[0]);
#if ENABLE_HUSH_FUNCTIONS
funcp = NULL;
if (!x)
funcp = find_function(argv_expanded[0]);
#endif
if (x || funcp) {
if (!funcp) {
if (x->b_function == builtin_exec && argv_expanded[1] == NULL) {
debug_printf("exec with redirects only\n");
rcode = setup_redirects(command, NULL);
goto clean_up_and_ret1;
}
}
rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, squirrel, argv_expanded);
if (rcode == 0) {
if (!funcp) {
debug_printf_exec(": builtin '%s' '%s'...\n",
x->b_cmd, argv_expanded[1]);
fflush_all();
rcode = x->b_function(argv_expanded) & 0xff;
fflush_all();
}
#if ENABLE_HUSH_FUNCTIONS
else {
# if ENABLE_HUSH_LOCAL
struct variable **sv;
sv = G.shadowed_vars_pp;
G.shadowed_vars_pp = &old_vars;
# endif
debug_printf_exec(": function '%s' '%s'...\n",
funcp->name, argv_expanded[1]);
rcode = run_function(funcp, argv_expanded) & 0xff;
# if ENABLE_HUSH_LOCAL
G.shadowed_vars_pp = sv;
# endif
}
#endif
}
clean_up_and_ret:
unset_vars(new_env);
add_vars(old_vars);
/* clean_up_and_ret0: */
restore_redirects(squirrel);
clean_up_and_ret1:
free(argv_expanded);
IF_HAS_KEYWORDS(if (pi->pi_inverted) rcode = !rcode;)
debug_leave();
debug_printf_exec("run_pipe return %d\n", rcode);
return rcode;
}
if (ENABLE_FEATURE_SH_NOFORK) {
int n = find_applet_by_name(argv_expanded[0]);
if (n >= 0 && APPLET_IS_NOFORK(n)) {
rcode = redirect_and_varexp_helper(&new_env, &old_vars, command, squirrel, argv_expanded);
if (rcode == 0) {
debug_printf_exec(": run_nofork_applet '%s' '%s'...\n",
argv_expanded[0], argv_expanded[1]);
rcode = run_nofork_applet(n, argv_expanded);
}
goto clean_up_and_ret;
}
}
/* It is neither builtin nor applet. We must fork. */
}
must_fork:
/* NB: argv_expanded may already be created, and that
* might include `cmd` runs! Do not rerun it! We *must*
* use argv_expanded if it's non-NULL */
/* Going to fork a child per each pipe member */
pi->alive_cmds = 0;
next_infd = 0;
cmd_no = 0;
while (cmd_no < pi->num_cmds) {
struct fd_pair pipefds;
#if !BB_MMU
volatile nommu_save_t nommu_save;
nommu_save.new_env = NULL;
nommu_save.old_vars = NULL;
nommu_save.argv = NULL;
nommu_save.argv_from_re_execing = NULL;
#endif
command = &pi->cmds[cmd_no];
cmd_no++;
if (command->argv) {
debug_printf_exec(": pipe member '%s' '%s'...\n",
command->argv[0], command->argv[1]);
} else {
debug_printf_exec(": pipe member with no argv\n");
}
/* pipes are inserted between pairs of commands */
pipefds.rd = 0;
pipefds.wr = 1;
if (cmd_no < pi->num_cmds)
xpiped_pair(pipefds);
command->pid = BB_MMU ? fork() : vfork();
if (!command->pid) { /* child */
#if ENABLE_HUSH_JOB
disable_restore_tty_pgrp_on_exit();
CLEAR_RANDOM_T(&G.random_gen); /* or else $RANDOM repeats in child */
/* Every child adds itself to new process group
* with pgid == pid_of_first_child_in_pipe */
if (G.run_list_level == 1 && G_interactive_fd) {
pid_t pgrp;
pgrp = pi->pgrp;
if (pgrp < 0) /* true for 1st process only */
pgrp = getpid();
if (setpgid(0, pgrp) == 0
&& pi->followup != PIPE_BG
&& G_saved_tty_pgrp /* we have ctty */
) {
/* We do it in *every* child, not just first,
* to avoid races */
tcsetpgrp(G_interactive_fd, pgrp);
}
}
#endif
if (pi->alive_cmds == 0 && pi->followup == PIPE_BG) {
/* 1st cmd in backgrounded pipe
* should have its stdin /dev/null'ed */
close(0);
if (open(bb_dev_null, O_RDONLY))
xopen("/", O_RDONLY);
} else {
xmove_fd(next_infd, 0);
}
xmove_fd(pipefds.wr, 1);
if (pipefds.rd > 1)
close(pipefds.rd);
/* Like bash, explicit redirects override pipes,
* and the pipe fd is available for dup'ing. */
if (setup_redirects(command, NULL))
_exit(1);
/* Stores to nommu_save list of env vars putenv'ed
* (NOMMU, on MMU we don't need that) */
/* cast away volatility... */
pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
/* pseudo_exec() does not return */
}
/* parent or error */
#if ENABLE_HUSH_FAST
G.count_SIGCHLD++;
//bb_error_msg("[%d] fork in run_pipe: G.count_SIGCHLD:%d G.handled_SIGCHLD:%d", getpid(), G.count_SIGCHLD, G.handled_SIGCHLD);
#endif
enable_restore_tty_pgrp_on_exit();
#if !BB_MMU
/* Clean up after vforked child */
free(nommu_save.argv);
free(nommu_save.argv_from_re_execing);
unset_vars(nommu_save.new_env);
add_vars(nommu_save.old_vars);
#endif
free(argv_expanded);
argv_expanded = NULL;
if (command->pid < 0) { /* [v]fork failed */
/* Clearly indicate, was it fork or vfork */
bb_perror_msg(BB_MMU ? "vfork"+1 : "vfork");
} else {
pi->alive_cmds++;
#if ENABLE_HUSH_JOB
/* Second and next children need to know pid of first one */
if (pi->pgrp < 0)
pi->pgrp = command->pid;
#endif
}
if (cmd_no > 1)
close(next_infd);
if (cmd_no < pi->num_cmds)
close(pipefds.wr);
/* Pass read (output) pipe end to next iteration */
next_infd = pipefds.rd;
}
if (!pi->alive_cmds) {
debug_leave();
debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n");
return 1;
}
debug_leave();
debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->alive_cmds);
return -1;
}
/* NB: called by pseudo_exec, and therefore must not modify any
* global data until exec/_exit (we can be a child after vfork!) */
static int run_list(struct pipe *pi)
{
#if ENABLE_HUSH_CASE
char *case_word = NULL;
#endif
#if ENABLE_HUSH_LOOPS
struct pipe *loop_top = NULL;
char **for_lcur = NULL;
char **for_list = NULL;
#endif
smallint last_followup;
smalluint rcode;
#if ENABLE_HUSH_IF || ENABLE_HUSH_CASE
smalluint cond_code = 0;
#else
enum { cond_code = 0 };
#endif
#if HAS_KEYWORDS
smallint rword; /* RES_foo */
smallint last_rword; /* ditto */
#endif
debug_printf_exec("run_list start lvl %d\n", G.run_list_level);
debug_enter();
#if ENABLE_HUSH_LOOPS
/* Check syntax for "for" */
{
struct pipe *cpipe;
for (cpipe = pi; cpipe; cpipe = cpipe->next) {
if (cpipe->res_word != RES_FOR && cpipe->res_word != RES_IN)
continue;
/* current word is FOR or IN (BOLD in comments below) */
if (cpipe->next == NULL) {
syntax_error("malformed for");
debug_leave();
debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
return 1;
}
/* "FOR v; do ..." and "for v IN a b; do..." are ok */
if (cpipe->next->res_word == RES_DO)
continue;
/* next word is not "do". It must be "in" then ("FOR v in ...") */
if (cpipe->res_word == RES_IN /* "for v IN a b; not_do..."? */
|| cpipe->next->res_word != RES_IN /* FOR v not_do_and_not_in..."? */
) {
syntax_error("malformed for");
debug_leave();
debug_printf_exec("run_list lvl %d return 1\n", G.run_list_level);
return 1;
}
}
}
#endif
/* Past this point, all code paths should jump to ret: label
* in order to return, no direct "return" statements please.
* This helps to ensure that no memory is leaked. */
#if ENABLE_HUSH_JOB
G.run_list_level++;
#endif
#if HAS_KEYWORDS
rword = RES_NONE;
last_rword = RES_XXXX;
#endif
last_followup = PIPE_SEQ;
rcode = G.last_exitcode;
/* Go through list of pipes, (maybe) executing them. */
for (; pi; pi = IF_HUSH_LOOPS(rword == RES_DONE ? loop_top : ) pi->next) {
if (G.flag_SIGINT)
break;
IF_HAS_KEYWORDS(rword = pi->res_word;)
debug_printf_exec(": rword=%d cond_code=%d last_rword=%d\n",
rword, cond_code, last_rword);
#if ENABLE_HUSH_LOOPS
if ((rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR)
&& loop_top == NULL /* avoid bumping G.depth_of_loop twice */
) {
/* start of a loop: remember where loop starts */
loop_top = pi;
G.depth_of_loop++;
}
#endif
/* Still in the same "if...", "then..." or "do..." branch? */
if (IF_HAS_KEYWORDS(rword == last_rword &&) 1) {
if ((rcode == 0 && last_followup == PIPE_OR)
|| (rcode != 0 && last_followup == PIPE_AND)
) {
/* It is "<true> || CMD" or "<false> && CMD"
* and we should not execute CMD */
debug_printf_exec("skipped cmd because of || or &&\n");
last_followup = pi->followup;
continue;
}
}
last_followup = pi->followup;
IF_HAS_KEYWORDS(last_rword = rword;)
#if ENABLE_HUSH_IF
if (cond_code) {
if (rword == RES_THEN) {
/* if false; then ... fi has exitcode 0! */
G.last_exitcode = rcode = EXIT_SUCCESS;
/* "if <false> THEN cmd": skip cmd */
continue;
}
} else {
if (rword == RES_ELSE || rword == RES_ELIF) {
/* "if <true> then ... ELSE/ELIF cmd":
* skip cmd and all following ones */
break;
}
}
#endif
#if ENABLE_HUSH_LOOPS
if (rword == RES_FOR) { /* && pi->num_cmds - always == 1 */
if (!for_lcur) {
/* first loop through for */
static const char encoded_dollar_at[] ALIGN1 = {
SPECIAL_VAR_SYMBOL, '@' | 0x80, SPECIAL_VAR_SYMBOL, '\0'
}; /* encoded representation of "$@" */
static const char *const encoded_dollar_at_argv[] = {
encoded_dollar_at, NULL
}; /* argv list with one element: "$@" */
char **vals;
vals = (char**)encoded_dollar_at_argv;
if (pi->next->res_word == RES_IN) {
/* if no variable values after "in" we skip "for" */
if (!pi->next->cmds[0].argv) {
G.last_exitcode = rcode = EXIT_SUCCESS;
debug_printf_exec(": null FOR: exitcode EXIT_SUCCESS\n");
break;
}
vals = pi->next->cmds[0].argv;
} /* else: "for var; do..." -> assume "$@" list */
/* create list of variable values */
debug_print_strings("for_list made from", vals);
for_list = expand_strvec_to_strvec(vals);
for_lcur = for_list;
debug_print_strings("for_list", for_list);
}
if (!*for_lcur) {
/* "for" loop is over, clean up */
free(for_list);
for_list = NULL;
for_lcur = NULL;
break;
}
/* Insert next value from for_lcur */
/* note: *for_lcur already has quotes removed, $var expanded, etc */
set_local_var(xasprintf("%s=%s", pi->cmds[0].argv[0], *for_lcur++), /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ 0);
continue;
}
if (rword == RES_IN) {
continue; /* "for v IN list;..." - "in" has no cmds anyway */
}
if (rword == RES_DONE) {
continue; /* "done" has no cmds too */
}
#endif
#if ENABLE_HUSH_CASE
if (rword == RES_CASE) {
case_word = expand_strvec_to_string(pi->cmds->argv);
continue;
}
if (rword == RES_MATCH) {
char **argv;
if (!case_word) /* "case ... matched_word) ... WORD)": we executed selected branch, stop */
break;
/* all prev words didn't match, does this one match? */
argv = pi->cmds->argv;
while (*argv) {
char *pattern = expand_string_to_string(*argv, /*unbackslash:*/ 1);
/* TODO: which FNM_xxx flags to use? */
cond_code = (fnmatch(pattern, case_word, /*flags:*/ 0) != 0);
free(pattern);
if (cond_code == 0) { /* match! we will execute this branch */
free(case_word); /* make future "word)" stop */
case_word = NULL;
break;
}
argv++;
}
continue;
}
if (rword == RES_CASE_BODY) { /* inside of a case branch */
if (cond_code != 0)
continue; /* not matched yet, skip this pipe */
}
#endif
/* Just pressing <enter> in shell should check for jobs.
* OTOH, in non-interactive shell this is useless
* and only leads to extra job checks */
if (pi->num_cmds == 0) {
if (G_interactive_fd)
goto check_jobs_and_continue;
continue;
}
/* After analyzing all keywords and conditions, we decided
* to execute this pipe. NB: have to do checkjobs(NULL)
* after run_pipe to collect any background children,
* even if list execution is to be stopped. */
debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
{
int r;
#if ENABLE_HUSH_LOOPS
G.flag_break_continue = 0;
#endif
rcode = r = run_pipe(pi); /* NB: rcode is a smallint */
if (r != -1) {
/* We ran a builtin, function, or group.
* rcode is already known
* and we don't need to wait for anything. */
G.last_exitcode = rcode;
debug_printf_exec(": builtin/func exitcode %d\n", rcode);
check_and_run_traps();
#if ENABLE_HUSH_LOOPS
/* Was it "break" or "continue"? */
if (G.flag_break_continue) {
smallint fbc = G.flag_break_continue;
/* We might fall into outer *loop*,
* don't want to break it too */
if (loop_top) {
G.depth_break_continue--;
if (G.depth_break_continue == 0)
G.flag_break_continue = 0;
/* else: e.g. "continue 2" should *break* once, *then* continue */
} /* else: "while... do... { we are here (innermost list is not a loop!) };...done" */
if (G.depth_break_continue != 0 || fbc == BC_BREAK)
goto check_jobs_and_break;
/* "continue": simulate end of loop */
rword = RES_DONE;
continue;
}
#endif
#if ENABLE_HUSH_FUNCTIONS
if (G.flag_return_in_progress == 1) {
/* same as "goto check_jobs_and_break" */
checkjobs(NULL);
break;
}
#endif
} else if (pi->followup == PIPE_BG) {
/* What does bash do with attempts to background builtins? */
/* even bash 3.2 doesn't do that well with nested bg:
* try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
* I'm NOT treating inner &'s as jobs */
check_and_run_traps();
#if ENABLE_HUSH_JOB
if (G.run_list_level == 1)
insert_bg_job(pi);
#endif
/* Last command's pid goes to $! */
G.last_bg_pid = pi->cmds[pi->num_cmds - 1].pid;
G.last_exitcode = rcode = EXIT_SUCCESS;
debug_printf_exec(": cmd&: exitcode EXIT_SUCCESS\n");
} else {
#if ENABLE_HUSH_JOB
if (G.run_list_level == 1 && G_interactive_fd) {
/* Waits for completion, then fg's main shell */
rcode = checkjobs_and_fg_shell(pi);
debug_printf_exec(": checkjobs_and_fg_shell exitcode %d\n", rcode);
check_and_run_traps();
} else
#endif
{ /* This one just waits for completion */
rcode = checkjobs(pi);
debug_printf_exec(": checkjobs exitcode %d\n", rcode);
check_and_run_traps();
}
G.last_exitcode = rcode;
}
}
/* Analyze how result affects subsequent commands */
#if ENABLE_HUSH_IF
if (rword == RES_IF || rword == RES_ELIF)
cond_code = rcode;
#endif
#if ENABLE_HUSH_LOOPS
/* Beware of "while false; true; do ..."! */
if (pi->next
&& (pi->next->res_word == RES_DO || pi->next->res_word == RES_DONE)
/* check for RES_DONE is needed for "while ...; do \n done" case */
) {
if (rword == RES_WHILE) {
if (rcode) {
/* "while false; do...done" - exitcode 0 */
G.last_exitcode = rcode = EXIT_SUCCESS;
debug_printf_exec(": while expr is false: breaking (exitcode:EXIT_SUCCESS)\n");
goto check_jobs_and_break;
}
}
if (rword == RES_UNTIL) {
if (!rcode) {
debug_printf_exec(": until expr is true: breaking\n");
check_jobs_and_break:
checkjobs(NULL);
break;
}
}
}
#endif
check_jobs_and_continue:
checkjobs(NULL);
} /* for (pi) */
#if ENABLE_HUSH_JOB
G.run_list_level--;
#endif
#if ENABLE_HUSH_LOOPS
if (loop_top)
G.depth_of_loop--;
free(for_list);
#endif
#if ENABLE_HUSH_CASE
free(case_word);
#endif
debug_leave();
debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
return rcode;
}
/* Select which version we will use */
static int run_and_free_list(struct pipe *pi)
{
int rcode = 0;
debug_printf_exec("run_and_free_list entered\n");
if (!G.o_opt[OPT_O_NOEXEC]) {
debug_printf_exec(": run_list: 1st pipe with %d cmds\n", pi->num_cmds);
rcode = run_list(pi);
}
/* free_pipe_list has the side effect of clearing memory.
* In the long run that function can be merged with run_list,
* but doing that now would hobble the debugging effort. */
free_pipe_list(pi);
debug_printf_exec("run_and_free_list return %d\n", rcode);
return rcode;
}
static void install_sighandlers(unsigned mask)
{
sighandler_t old_handler;
unsigned sig = 0;
while ((mask >>= 1) != 0) {
sig++;
if (!(mask & 1))
continue;
old_handler = install_sighandler(sig, pick_sighandler(sig));
/* POSIX allows shell to re-enable SIGCHLD
* even if it was SIG_IGN on entry.
* Therefore we skip IGN check for it:
*/
if (sig == SIGCHLD)
continue;
if (old_handler == SIG_IGN) {
/* oops... restore back to IGN, and record this fact */
install_sighandler(sig, old_handler);
if (!G.traps)
G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
free(G.traps[sig]);
G.traps[sig] = xzalloc(1); /* == xstrdup(""); */
}
}
}
/* Called a few times only (or even once if "sh -c") */
static void install_special_sighandlers(void)
{
unsigned mask;
/* Which signals are shell-special? */
mask = (1 << SIGQUIT) | (1 << SIGCHLD);
if (G_interactive_fd) {
mask |= SPECIAL_INTERACTIVE_SIGS;
if (G_saved_tty_pgrp) /* we have ctty, job control sigs work */
mask |= SPECIAL_JOBSTOP_SIGS;
}
/* Careful, do not re-install handlers we already installed */
if (G.special_sig_mask != mask) {
unsigned diff = mask & ~G.special_sig_mask;
G.special_sig_mask = mask;
install_sighandlers(diff);
}
}
#if ENABLE_HUSH_JOB
/* helper */
/* Set handlers to restore tty pgrp and exit */
static void install_fatal_sighandlers(void)
{
unsigned mask;
/* We will restore tty pgrp on these signals */
mask = 0
+ (1 << SIGILL ) * HUSH_DEBUG
+ (1 << SIGFPE ) * HUSH_DEBUG
+ (1 << SIGBUS ) * HUSH_DEBUG
+ (1 << SIGSEGV) * HUSH_DEBUG
+ (1 << SIGTRAP) * HUSH_DEBUG
+ (1 << SIGABRT)
/* bash 3.2 seems to handle these just like 'fatal' ones */
+ (1 << SIGPIPE)
+ (1 << SIGALRM)
/* if we are interactive, SIGHUP, SIGTERM and SIGINT are special sigs.
* if we aren't interactive... but in this case
* we never want to restore pgrp on exit, and this fn is not called
*/
/*+ (1 << SIGHUP )*/
/*+ (1 << SIGTERM)*/
/*+ (1 << SIGINT )*/
;
G_fatal_sig_mask = mask;
install_sighandlers(mask);
}
#endif
static int set_mode(int state, char mode, const char *o_opt)
{
int idx;
switch (mode) {
case 'n':
G.o_opt[OPT_O_NOEXEC] = state;
break;
case 'x':
IF_HUSH_MODE_X(G_x_mode = state;)
break;
case 'o':
if (!o_opt) {
/* "set -+o" without parameter.
* in bash, set -o produces this output:
* pipefail off
* and set +o:
* set +o pipefail
* We always use the second form.
*/
const char *p = o_opt_strings;
idx = 0;
while (*p) {
printf("set %co %s\n", (G.o_opt[idx] ? '-' : '+'), p);
idx++;
p += strlen(p) + 1;
}
break;
}
idx = index_in_strings(o_opt_strings, o_opt);
if (idx >= 0) {
G.o_opt[idx] = state;
break;
}
default:
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int hush_main(int argc, char **argv)
{
enum {
OPT_login = (1 << 0),
};
unsigned flags;
int opt;
unsigned builtin_argc;
char **e;
struct variable *cur_var;
struct variable *shell_ver;
INIT_G();
if (EXIT_SUCCESS != 0) /* if EXIT_SUCCESS == 0, it is already done */
G.last_exitcode = EXIT_SUCCESS;
#if ENABLE_HUSH_FAST
G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
#endif
#if !BB_MMU
G.argv0_for_re_execing = argv[0];
#endif
/* Deal with HUSH_VERSION */
shell_ver = xzalloc(sizeof(*shell_ver));
shell_ver->flg_export = 1;
shell_ver->flg_read_only = 1;
/* Code which handles ${var<op>...} needs writable values for all variables,
* therefore we xstrdup: */
shell_ver->varstr = xstrdup(hush_version_str);
/* Create shell local variables from the values
* currently living in the environment */
debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
unsetenv("HUSH_VERSION"); /* in case it exists in initial env */
G.top_var = shell_ver;
cur_var = G.top_var;
e = environ;
if (e) while (*e) {
char *value = strchr(*e, '=');
if (value) { /* paranoia */
cur_var->next = xzalloc(sizeof(*cur_var));
cur_var = cur_var->next;
cur_var->varstr = *e;
cur_var->max_len = strlen(*e);
cur_var->flg_export = 1;
}
e++;
}
/* (Re)insert HUSH_VERSION into env (AFTER we scanned the env!) */
debug_printf_env("putenv '%s'\n", shell_ver->varstr);
putenv(shell_ver->varstr);
/* Export PWD */
set_pwd_var(/*exp:*/ 1);
/* bash also exports SHLVL and _,
* and sets (but doesn't export) the following variables:
* BASH=/bin/bash
* BASH_VERSINFO=([0]="3" [1]="2" [2]="0" [3]="1" [4]="release" [5]="i386-pc-linux-gnu")
* BASH_VERSION='3.2.0(1)-release'
* HOSTTYPE=i386
* MACHTYPE=i386-pc-linux-gnu
* OSTYPE=linux-gnu
* HOSTNAME=<xxxxxxxxxx>
* PPID=<NNNNN> - we also do it elsewhere
* EUID=<NNNNN>
* UID=<NNNNN>
* GROUPS=()
* LINES=<NNN>
* COLUMNS=<NNN>
* BASH_ARGC=()
* BASH_ARGV=()
* BASH_LINENO=()
* BASH_SOURCE=()
* DIRSTACK=()
* PIPESTATUS=([0]="0")
* HISTFILE=/<xxx>/.bash_history
* HISTFILESIZE=500
* HISTSIZE=500
* MAILCHECK=60
* PATH=/usr/gnu/bin:/usr/local/bin:/bin:/usr/bin:.
* SHELL=/bin/bash
* SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor
* TERM=dumb
* OPTERR=1
* OPTIND=1
* IFS=$' \t\n'
* PS1='\s-\v\$ '
* PS2='> '
* PS4='+ '
*/
#if ENABLE_FEATURE_EDITING
G.line_input_state = new_line_input_t(FOR_SHELL);
# if defined MAX_HISTORY && MAX_HISTORY > 0 && ENABLE_HUSH_SAVEHISTORY
{
const char *hp = get_local_var_value("HISTFILE");
if (!hp) {
hp = get_local_var_value("HOME");
if (hp) {
G.line_input_state->hist_file = concat_path_file(hp, ".hush_history");
//set_local_var(xasprintf("HISTFILE=%s", ...));
}
}
# if ENABLE_FEATURE_SH_HISTFILESIZE
hp = get_local_var_value("HISTFILESIZE");
G.line_input_state->max_history = size_from_HISTFILESIZE(hp);
# endif
}
# endif
#endif
/* Initialize some more globals to non-zero values */
cmdedit_update_prompt();
if (setjmp(die_jmp)) {
/* xfunc has failed! die die die */
/* no EXIT traps, this is an escape hatch! */
G.exiting = 1;
hush_exit(xfunc_error_retval);
}
/* Shell is non-interactive at first. We need to call
* install_special_sighandlers() if we are going to execute "sh <script>",
* "sh -c <cmds>" or login shell's /etc/profile and friends.
* If we later decide that we are interactive, we run install_special_sighandlers()
* in order to intercept (more) signals.
*/
/* Parse options */
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
flags = (argv[0] && argv[0][0] == '-') ? OPT_login : 0;
builtin_argc = 0;
while (1) {
opt = getopt(argc, argv, "+c:xinsl"
#if !BB_MMU
"<:$:R:V:"
# if ENABLE_HUSH_FUNCTIONS
"F:"
# endif
#endif
);
if (opt <= 0)
break;
switch (opt) {
case 'c':
/* Possibilities:
* sh ... -c 'script'
* sh ... -c 'script' ARG0 [ARG1...]
* On NOMMU, if builtin_argc != 0,
* sh ... -c 'builtin' BARGV... "" ARG0 [ARG1...]
* "" needs to be replaced with NULL
* and BARGV vector fed to builtin function.
* Note: the form without ARG0 never happens:
* sh ... -c 'builtin' BARGV... ""
*/
if (!G.root_pid) {
G.root_pid = getpid();
G.root_ppid = getppid();
}
G.global_argv = argv + optind;
G.global_argc = argc - optind;
if (builtin_argc) {
/* -c 'builtin' [BARGV...] "" ARG0 [ARG1...] */
const struct built_in_command *x;
install_special_sighandlers();
x = find_builtin(optarg);
if (x) { /* paranoia */
G.global_argc -= builtin_argc; /* skip [BARGV...] "" */
G.global_argv += builtin_argc;
G.global_argv[-1] = NULL; /* replace "" */
fflush_all();
G.last_exitcode = x->b_function(argv + optind - 1);
}
goto final_return;
}
if (!G.global_argv[0]) {
/* -c 'script' (no params): prevent empty $0 */
G.global_argv--; /* points to argv[i] of 'script' */
G.global_argv[0] = argv[0];
G.global_argc++;
} /* else -c 'script' ARG0 [ARG1...]: $0 is ARG0 */
install_special_sighandlers();
parse_and_run_string(optarg);
goto final_return;
case 'i':
/* Well, we cannot just declare interactiveness,
* we have to have some stuff (ctty, etc) */
/* G_interactive_fd++; */
break;
case 's':
/* "-s" means "read from stdin", but this is how we always
* operate, so simply do nothing here. */
break;
case 'l':
flags |= OPT_login;
break;
#if !BB_MMU
case '<': /* "big heredoc" support */
full_write1_str(optarg);
_exit(0);
case '$': {
unsigned long long empty_trap_mask;
G.root_pid = bb_strtou(optarg, &optarg, 16);
optarg++;
G.root_ppid = bb_strtou(optarg, &optarg, 16);
optarg++;
G.last_bg_pid = bb_strtou(optarg, &optarg, 16);
optarg++;
G.last_exitcode = bb_strtou(optarg, &optarg, 16);
optarg++;
builtin_argc = bb_strtou(optarg, &optarg, 16);
optarg++;
empty_trap_mask = bb_strtoull(optarg, &optarg, 16);
if (empty_trap_mask != 0) {
int sig;
install_special_sighandlers();
G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
for (sig = 1; sig < NSIG; sig++) {
if (empty_trap_mask & (1LL << sig)) {
G.traps[sig] = xzalloc(1); /* == xstrdup(""); */
install_sighandler(sig, SIG_IGN);
}
}
}
# if ENABLE_HUSH_LOOPS
optarg++;
G.depth_of_loop = bb_strtou(optarg, &optarg, 16);
# endif
break;
}
case 'R':
case 'V':
set_local_var(xstrdup(optarg), /*exp:*/ 0, /*lvl:*/ 0, /*ro:*/ opt == 'R');
break;
# if ENABLE_HUSH_FUNCTIONS
case 'F': {
struct function *funcp = new_function(optarg);
/* funcp->name is already set to optarg */
/* funcp->body is set to NULL. It's a special case. */
funcp->body_as_string = argv[optind];
optind++;
break;
}
# endif
#endif
case 'n':
case 'x':
if (set_mode(1, opt, NULL) == 0) /* no error */
break;
default:
#ifndef BB_VER
fprintf(stderr, "Usage: sh [FILE]...\n"
" or: sh -c command [args]...\n\n");
exit(EXIT_FAILURE);
#else
bb_show_usage();
#endif
}
} /* option parsing loop */
/* Skip options. Try "hush -l": $1 should not be "-l"! */
G.global_argc = argc - (optind - 1);
G.global_argv = argv + (optind - 1);
G.global_argv[0] = argv[0];
if (!G.root_pid) {
G.root_pid = getpid();
G.root_ppid = getppid();
}
/* If we are login shell... */
if (flags & OPT_login) {
FILE *input;
debug_printf("sourcing /etc/profile\n");
input = fopen_for_read("/etc/profile");
if (input != NULL) {
close_on_exec_on(fileno(input));
install_special_sighandlers();
parse_and_run_file(input);
fclose(input);
}
/* bash: after sourcing /etc/profile,
* tries to source (in the given order):
* ~/.bash_profile, ~/.bash_login, ~/.profile,
* stopping on first found. --noprofile turns this off.
* bash also sources ~/.bash_logout on exit.
* If called as sh, skips .bash_XXX files.
*/
}
if (G.global_argv[1]) {
FILE *input;
/*
* "bash <script>" (which is never interactive (unless -i?))
* sources $BASH_ENV here (without scanning $PATH).
* If called as sh, does the same but with $ENV.
*/
G.global_argc--;
G.global_argv++;
debug_printf("running script '%s'\n", G.global_argv[0]);
input = xfopen_for_read(G.global_argv[0]);
close_on_exec_on(fileno(input));
install_special_sighandlers();
parse_and_run_file(input);
#if ENABLE_FEATURE_CLEAN_UP
fclose(input);
#endif
goto final_return;
}
/* Up to here, shell was non-interactive. Now it may become one.
* NB: don't forget to (re)run install_special_sighandlers() as needed.
*/
/* A shell is interactive if the '-i' flag was given,
* or if all of the following conditions are met:
* no -c command
* no arguments remaining or the -s flag given
* standard input is a terminal
* standard output is a terminal
* Refer to Posix.2, the description of the 'sh' utility.
*/
#if ENABLE_HUSH_JOB
if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
G_saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
debug_printf("saved_tty_pgrp:%d\n", G_saved_tty_pgrp);
if (G_saved_tty_pgrp < 0)
G_saved_tty_pgrp = 0;
/* try to dup stdin to high fd#, >= 255 */
G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
if (G_interactive_fd < 0) {
/* try to dup to any fd */
G_interactive_fd = dup(STDIN_FILENO);
if (G_interactive_fd < 0) {
/* give up */
G_interactive_fd = 0;
G_saved_tty_pgrp = 0;
}
}
// TODO: track & disallow any attempts of user
// to (inadvertently) close/redirect G_interactive_fd
}
debug_printf("interactive_fd:%d\n", G_interactive_fd);
if (G_interactive_fd) {
close_on_exec_on(G_interactive_fd);
if (G_saved_tty_pgrp) {
/* If we were run as 'hush &', sleep until we are
* in the foreground (tty pgrp == our pgrp).
* If we get started under a job aware app (like bash),
* make sure we are now in charge so we don't fight over
* who gets the foreground */
while (1) {
pid_t shell_pgrp = getpgrp();
G_saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
if (G_saved_tty_pgrp == shell_pgrp)
break;
/* send TTIN to ourself (should stop us) */
kill(- shell_pgrp, SIGTTIN);
}
}
/* Install more signal handlers */
install_special_sighandlers();
if (G_saved_tty_pgrp) {
/* Set other signals to restore saved_tty_pgrp */
install_fatal_sighandlers();
/* Put ourselves in our own process group
* (bash, too, does this only if ctty is available) */
bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
/* Grab control of the terminal */
tcsetpgrp(G_interactive_fd, getpid());
}
/* -1 is special - makes xfuncs longjmp, not exit
* (we reset die_sleep = 0 whereever we [v]fork) */
enable_restore_tty_pgrp_on_exit(); /* sets die_sleep = -1 */
} else {
install_special_sighandlers();
}
#elif ENABLE_HUSH_INTERACTIVE
/* No job control compiled in, only prompt/line editing */
if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
if (G_interactive_fd < 0) {
/* try to dup to any fd */
G_interactive_fd = dup(STDIN_FILENO);
if (G_interactive_fd < 0)
/* give up */
G_interactive_fd = 0;
}
}
if (G_interactive_fd) {
close_on_exec_on(G_interactive_fd);
}
install_special_sighandlers();
#else
/* We have interactiveness code disabled */
install_special_sighandlers();
#endif
/* bash:
* if interactive but not a login shell, sources ~/.bashrc
* (--norc turns this off, --rcfile <file> overrides)
*/
if (!ENABLE_FEATURE_SH_EXTRA_QUIET && G_interactive_fd) {
/* note: ash and hush share this string */
printf("\n\n%s %s\n"
IF_HUSH_HELP("Enter 'help' for a list of built-in commands.\n")
"\n",
bb_banner,
"hush - the humble shell"
);
}
parse_and_run_file(stdin);
final_return:
hush_exit(G.last_exitcode);
}
#if ENABLE_MSH
int msh_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int msh_main(int argc, char **argv)
{
//bb_error_msg("msh is deprecated, please use hush instead");
return hush_main(argc, argv);
}
#endif
/*
* Built-ins
*/
static int FAST_FUNC builtin_true(char **argv UNUSED_PARAM)
{
return 0;
}
static int run_applet_main(char **argv, int (*applet_main_func)(int argc, char **argv))
{
int argc = 0;
while (*argv) {
argc++;
argv++;
}
return applet_main_func(argc, argv - argc);
}
static int FAST_FUNC builtin_test(char **argv)
{
return run_applet_main(argv, test_main);
}
static int FAST_FUNC builtin_echo(char **argv)
{
return run_applet_main(argv, echo_main);
}
#if ENABLE_PRINTF
static int FAST_FUNC builtin_printf(char **argv)
{
return run_applet_main(argv, printf_main);
}
#endif
static char **skip_dash_dash(char **argv)
{
argv++;
if (argv[0] && argv[0][0] == '-' && argv[0][1] == '-' && argv[0][2] == '\0')
argv++;
return argv;
}
static int FAST_FUNC builtin_eval(char **argv)
{
int rcode = EXIT_SUCCESS;
argv = skip_dash_dash(argv);
if (*argv) {
char *str = expand_strvec_to_string(argv);
/* bash:
* eval "echo Hi; done" ("done" is syntax error):
* "echo Hi" will not execute too.
*/
parse_and_run_string(str);
free(str);
rcode = G.last_exitcode;
}
return rcode;
}
static int FAST_FUNC builtin_cd(char **argv)
{
const char *newdir;
argv = skip_dash_dash(argv);
newdir = argv[0];
if (newdir == NULL) {
/* bash does nothing (exitcode 0) if HOME is ""; if it's unset,
* bash says "bash: cd: HOME not set" and does nothing
* (exitcode 1)
*/
const char *home = get_local_var_value("HOME");
newdir = home ? home : "/";
}
if (chdir(newdir)) {
/* Mimic bash message exactly */
bb_perror_msg("cd: %s", newdir);
return EXIT_FAILURE;
}
/* Read current dir (get_cwd(1) is inside) and set PWD.
* Note: do not enforce exporting. If PWD was unset or unexported,
* set it again, but do not export. bash does the same.
*/
set_pwd_var(/*exp:*/ 0);
return EXIT_SUCCESS;
}
static int FAST_FUNC builtin_exec(char **argv)
{
argv = skip_dash_dash(argv);
if (argv[0] == NULL)
return EXIT_SUCCESS; /* bash does this */
/* Careful: we can end up here after [v]fork. Do not restore
* tty pgrp then, only top-level shell process does that */
if (G_saved_tty_pgrp && getpid() == G.root_pid)
tcsetpgrp(G_interactive_fd, G_saved_tty_pgrp);
/* TODO: if exec fails, bash does NOT exit! We do.
* We'll need to undo trap cleanup (it's inside execvp_or_die)
* and tcsetpgrp, and this is inherently racy.
*/
execvp_or_die(argv);
}
static int FAST_FUNC builtin_exit(char **argv)
{
debug_printf_exec("%s()\n", __func__);
/* interactive bash:
* # trap "echo EEE" EXIT
* # exit
* exit
* There are stopped jobs.
* (if there are _stopped_ jobs, running ones don't count)
* # exit
* exit
# EEE (then bash exits)
*
* TODO: we can use G.exiting = -1 as indicator "last cmd was exit"
*/
/* note: EXIT trap is run by hush_exit */
argv = skip_dash_dash(argv);
if (argv[0] == NULL)
hush_exit(G.last_exitcode);
/* mimic bash: exit 123abc == exit 255 + error msg */
xfunc_error_retval = 255;
/* bash: exit -2 == exit 254, no error msg */
hush_exit(xatoi(argv[0]) & 0xff);
}
static void print_escaped(const char *s)
{
if (*s == '\'')
goto squote;
do {
const char *p = strchrnul(s, '\'');
/* print 'xxxx', possibly just '' */
printf("'%.*s'", (int)(p - s), s);
if (*p == '\0')
break;
s = p;
squote:
/* s points to '; print "'''...'''" */
putchar('"');
do putchar('\''); while (*++s == '\'');
putchar('"');
} while (*s);
}
#if !ENABLE_HUSH_LOCAL
#define helper_export_local(argv, exp, lvl) \
helper_export_local(argv, exp)
#endif
static void helper_export_local(char **argv, int exp, int lvl)
{
do {
char *name = *argv;
char *name_end = strchrnul(name, '=');
/* So far we do not check that name is valid (TODO?) */
if (*name_end == '\0') {
struct variable *var, **vpp;
vpp = get_ptr_to_local_var(name, name_end - name);
var = vpp ? *vpp : NULL;
if (exp == -1) { /* unexporting? */
/* export -n NAME (without =VALUE) */
if (var) {
var->flg_export = 0;
debug_printf_env("%s: unsetenv '%s'\n", __func__, name);
unsetenv(name);
} /* else: export -n NOT_EXISTING_VAR: no-op */
continue;
}
if (exp == 1) { /* exporting? */
/* export NAME (without =VALUE) */
if (var) {
var->flg_export = 1;
debug_printf_env("%s: putenv '%s'\n", __func__, var->varstr);
putenv(var->varstr);
continue;
}
}
/* Exporting non-existing variable.
* bash does not put it in environment,
* but remembers that it is exported,
* and does put it in env when it is set later.
* We just set it to "" and export. */
/* Or, it's "local NAME" (without =VALUE).
* bash sets the value to "". */
name = xasprintf("%s=", name);
} else {
/* (Un)exporting/making local NAME=VALUE */
name = xstrdup(name);
}
set_local_var(name, /*exp:*/ exp, /*lvl:*/ lvl, /*ro:*/ 0);
} while (*++argv);
}
static int FAST_FUNC builtin_export(char **argv)
{
unsigned opt_unexport;
#if ENABLE_HUSH_EXPORT_N
/* "!": do not abort on errors */
opt_unexport = getopt32(argv, "!n");
if (opt_unexport == (uint32_t)-1)
return EXIT_FAILURE;
argv += optind;
#else
opt_unexport = 0;
argv++;
#endif
if (argv[0] == NULL) {
char **e = environ;
if (e) {
while (*e) {
#if 0
puts(*e++);
#else
/* ash emits: export VAR='VAL'
* bash: declare -x VAR="VAL"
* we follow ash example */
const char *s = *e++;
const char *p = strchr(s, '=');
if (!p) /* wtf? take next variable */
continue;
/* export var= */
printf("export %.*s", (int)(p - s) + 1, s);
print_escaped(p + 1);
putchar('\n');
#endif
}
/*fflush_all(); - done after each builtin anyway */
}
return EXIT_SUCCESS;
}
helper_export_local(argv, (opt_unexport ? -1 : 1), 0);
return EXIT_SUCCESS;
}
#if ENABLE_HUSH_LOCAL
static int FAST_FUNC builtin_local(char **argv)
{
if (G.func_nest_level == 0) {
bb_error_msg("%s: not in a function", argv[0]);
return EXIT_FAILURE; /* bash compat */
}
helper_export_local(argv, 0, G.func_nest_level);
return EXIT_SUCCESS;
}
#endif
static int FAST_FUNC builtin_trap(char **argv)
{
int sig;
char *new_cmd;
if (!G.traps)
G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
argv++;
if (!*argv) {
int i;
/* No args: print all trapped */
for (i = 0; i < NSIG; ++i) {
if (G.traps[i]) {
printf("trap -- ");
print_escaped(G.traps[i]);
/* note: bash adds "SIG", but only if invoked
* as "bash". If called as "sh", or if set -o posix,
* then it prints short signal names.
* We are printing short names: */
printf(" %s\n", get_signame(i));
}
}
/*fflush_all(); - done after each builtin anyway */
return EXIT_SUCCESS;
}
new_cmd = NULL;
/* If first arg is a number: reset all specified signals */
sig = bb_strtou(*argv, NULL, 10);
if (errno == 0) {
int ret;
process_sig_list:
ret = EXIT_SUCCESS;
while (*argv) {
sighandler_t handler;
sig = get_signum(*argv++);
if (sig < 0 || sig >= NSIG) {
ret = EXIT_FAILURE;
/* Mimic bash message exactly */
bb_perror_msg("trap: %s: invalid signal specification", argv[-1]);
continue;
}
free(G.traps[sig]);
G.traps[sig] = xstrdup(new_cmd);
debug_printf("trap: setting SIG%s (%i) to '%s'\n",
get_signame(sig), sig, G.traps[sig]);
/* There is no signal for 0 (EXIT) */
if (sig == 0)
continue;
if (new_cmd)
handler = (new_cmd[0] ? record_pending_signo : SIG_IGN);
else
/* We are removing trap handler */
handler = pick_sighandler(sig);
install_sighandler(sig, handler);
}
return ret;
}
if (!argv[1]) { /* no second arg */
bb_error_msg("trap: invalid arguments");
return EXIT_FAILURE;
}
/* First arg is "-": reset all specified to default */
/* First arg is "--": skip it, the rest is "handler SIGs..." */
/* Everything else: set arg as signal handler
* (includes "" case, which ignores signal) */
if (argv[0][0] == '-') {
if (argv[0][1] == '\0') { /* "-" */
/* new_cmd remains NULL: "reset these sigs" */
goto reset_traps;
}
if (argv[0][1] == '-' && argv[0][2] == '\0') { /* "--" */
argv++;
}
/* else: "-something", no special meaning */
}
new_cmd = *argv;
reset_traps:
argv++;
goto process_sig_list;
}
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/type.html */
static int FAST_FUNC builtin_type(char **argv)
{
int ret = EXIT_SUCCESS;
while (*++argv) {
const char *type;
char *path = NULL;
if (0) {} /* make conditional compile easier below */
/*else if (find_alias(*argv))
type = "an alias";*/
#if ENABLE_HUSH_FUNCTIONS
else if (find_function(*argv))
type = "a function";
#endif
else if (find_builtin(*argv))
type = "a shell builtin";
else if ((path = find_in_path(*argv)) != NULL)
type = path;
else {
bb_error_msg("type: %s: not found", *argv);
ret = EXIT_FAILURE;
continue;
}
printf("%s is %s\n", *argv, type);
free(path);
}
return ret;
}
#if ENABLE_HUSH_JOB
/* built-in 'fg' and 'bg' handler */
static int FAST_FUNC builtin_fg_bg(char **argv)
{
int i, jobnum;
struct pipe *pi;
if (!G_interactive_fd)
return EXIT_FAILURE;
/* If they gave us no args, assume they want the last backgrounded task */
if (!argv[1]) {
for (pi = G.job_list; pi; pi = pi->next) {
if (pi->jobid == G.last_jobid) {
goto found;
}
}
bb_error_msg("%s: no current job", argv[0]);
return EXIT_FAILURE;
}
if (sscanf(argv[1], "%%%d", &jobnum) != 1) {
bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]);
return EXIT_FAILURE;
}
for (pi = G.job_list; pi; pi = pi->next) {
if (pi->jobid == jobnum) {
goto found;
}
}
bb_error_msg("%s: %d: no such job", argv[0], jobnum);
return EXIT_FAILURE;
found:
/* TODO: bash prints a string representation
* of job being foregrounded (like "sleep 1 | cat") */
if (argv[0][0] == 'f' && G_saved_tty_pgrp) {
/* Put the job into the foreground. */
tcsetpgrp(G_interactive_fd, pi->pgrp);
}
/* Restart the processes in the job */
debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_cmds, pi->pgrp);
for (i = 0; i < pi->num_cmds; i++) {
debug_printf_jobs("reviving pid %d\n", pi->cmds[i].pid);
pi->cmds[i].is_stopped = 0;
}
pi->stopped_cmds = 0;
i = kill(- pi->pgrp, SIGCONT);
if (i < 0) {
if (errno == ESRCH) {
delete_finished_bg_job(pi);
return EXIT_SUCCESS;
}
bb_perror_msg("kill (SIGCONT)");
}
if (argv[0][0] == 'f') {
remove_bg_job(pi);
return checkjobs_and_fg_shell(pi);
}
return EXIT_SUCCESS;
}
#endif
#if ENABLE_HUSH_HELP
static int FAST_FUNC builtin_help(char **argv UNUSED_PARAM)
{
const struct built_in_command *x;
printf(
"Built-in commands:\n"
"------------------\n");
for (x = bltins1; x != &bltins1[ARRAY_SIZE(bltins1)]; x++) {
if (x->b_descr)
printf("%-10s%s\n", x->b_cmd, x->b_descr);
}
bb_putchar('\n');
return EXIT_SUCCESS;
}
#endif
#if ENABLE_HUSH_JOB
static int FAST_FUNC builtin_jobs(char **argv UNUSED_PARAM)
{
struct pipe *job;
const char *status_string;
for (job = G.job_list; job; job = job->next) {
if (job->alive_cmds == job->stopped_cmds)
status_string = "Stopped";
else
status_string = "Running";
printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext);
}
return EXIT_SUCCESS;
}
#endif
#if HUSH_DEBUG
static int FAST_FUNC builtin_memleak(char **argv UNUSED_PARAM)
{
void *p;
unsigned long l;
# ifdef M_TRIM_THRESHOLD
/* Optional. Reduces probability of false positives */
malloc_trim(0);
# endif
/* Crude attempt to find where "free memory" starts,
* sans fragmentation. */
p = malloc(240);
l = (unsigned long)p;
free(p);
p = malloc(3400);
if (l < (unsigned long)p) l = (unsigned long)p;
free(p);
if (!G.memleak_value)
G.memleak_value = l;
l -= G.memleak_value;
if ((long)l < 0)
l = 0;
l /= 1024;
if (l > 127)
l = 127;
/* Exitcode is "how many kilobytes we leaked since 1st call" */
return l;
}
#endif
static int FAST_FUNC builtin_pwd(char **argv UNUSED_PARAM)
{
puts(get_cwd(0));
return EXIT_SUCCESS;
}
/* Interruptibility of read builtin in bash
* (tested on bash-4.2.8 by sending signals (not by ^C)):
*
* Empty trap makes read ignore corresponding signal, for any signal.
*
* SIGINT:
* - terminates non-interactive shell;
* - interrupts read in interactive shell;
* if it has non-empty trap:
* - executes trap and returns to command prompt in interactive shell;
* - executes trap and returns to read in non-interactive shell;
* SIGTERM:
* - is ignored (does not interrupt) read in interactive shell;
* - terminates non-interactive shell;
* if it has non-empty trap:
* - executes trap and returns to read;
* SIGHUP:
* - terminates shell (regardless of interactivity);
* if it has non-empty trap:
* - executes trap and returns to read;
*/
static int FAST_FUNC builtin_read(char **argv)
{
const char *r;
char *opt_n = NULL;
char *opt_p = NULL;
char *opt_t = NULL;
char *opt_u = NULL;
const char *ifs;
int read_flags;
/* "!": do not abort on errors.
* Option string must start with "sr" to match BUILTIN_READ_xxx
*/
read_flags = getopt32(argv, "!srn:p:t:u:", &opt_n, &opt_p, &opt_t, &opt_u);
if (read_flags == (uint32_t)-1)
return EXIT_FAILURE;
argv += optind;
ifs = get_local_var_value("IFS"); /* can be NULL */
again:
r = shell_builtin_read(set_local_var_from_halves,
argv,
ifs,
read_flags,
opt_n,
opt_p,
opt_t,
opt_u
);
if ((uintptr_t)r == 1 && errno == EINTR) {
unsigned sig = check_and_run_traps();
if (sig && sig != SIGINT)
goto again;
}
if ((uintptr_t)r > 1) {
bb_error_msg("%s", r);
r = (char*)(uintptr_t)1;
}
return (uintptr_t)r;
}
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set
* built-in 'set' handler
* SUSv3 says:
* set [-abCefhmnuvx] [-o option] [argument...]
* set [+abCefhmnuvx] [+o option] [argument...]
* set -- [argument...]
* set -o
* set +o
* Implementations shall support the options in both their hyphen and
* plus-sign forms. These options can also be specified as options to sh.
* Examples:
* Write out all variables and their values: set
* Set $1, $2, and $3 and set "$#" to 3: set c a b
* Turn on the -x and -v options: set -xv
* Unset all positional parameters: set --
* Set $1 to the value of x, even if it begins with '-' or '+': set -- "$x"
* Set the positional parameters to the expansion of x, even if x expands
* with a leading '-' or '+': set -- $x
*
* So far, we only support "set -- [argument...]" and some of the short names.
*/
static int FAST_FUNC builtin_set(char **argv)
{
int n;
char **pp, **g_argv;
char *arg = *++argv;
if (arg == NULL) {
struct variable *e;
for (e = G.top_var; e; e = e->next)
puts(e->varstr);
return EXIT_SUCCESS;
}
do {
if (strcmp(arg, "--") == 0) {
++argv;
goto set_argv;
}
if (arg[0] != '+' && arg[0] != '-')
break;
for (n = 1; arg[n]; ++n) {
if (set_mode((arg[0] == '-'), arg[n], argv[1]))
goto error;
if (arg[n] == 'o' && argv[1])
argv++;
}
} while ((arg = *++argv) != NULL);
/* Now argv[0] is 1st argument */
if (arg == NULL)
return EXIT_SUCCESS;
set_argv:
/* NB: G.global_argv[0] ($0) is never freed/changed */
g_argv = G.global_argv;
if (G.global_args_malloced) {
pp = g_argv;
while (*++pp)
free(*pp);
g_argv[1] = NULL;
} else {
G.global_args_malloced = 1;
pp = xzalloc(sizeof(pp[0]) * 2);
pp[0] = g_argv[0]; /* retain $0 */
g_argv = pp;
}
/* This realloc's G.global_argv */
G.global_argv = pp = add_strings_to_strings(g_argv, argv, /*dup:*/ 1);
n = 1;
while (*++pp)
n++;
G.global_argc = n;
return EXIT_SUCCESS;
/* Nothing known, so abort */
error:
bb_error_msg("set: %s: invalid option", arg);
return EXIT_FAILURE;
}
static int FAST_FUNC builtin_shift(char **argv)
{
int n = 1;
argv = skip_dash_dash(argv);
if (argv[0]) {
n = atoi(argv[0]);
}
if (n >= 0 && n < G.global_argc) {
if (G.global_args_malloced) {
int m = 1;
while (m <= n)
free(G.global_argv[m++]);
}
G.global_argc -= n;
memmove(&G.global_argv[1], &G.global_argv[n+1],
G.global_argc * sizeof(G.global_argv[0]));
return EXIT_SUCCESS;
}
return EXIT_FAILURE;
}
static int FAST_FUNC builtin_source(char **argv)
{
char *arg_path, *filename;
FILE *input;
save_arg_t sv;
#if ENABLE_HUSH_FUNCTIONS
smallint sv_flg;
#endif
argv = skip_dash_dash(argv);
filename = argv[0];
if (!filename) {
/* bash says: "bash: .: filename argument required" */
return 2; /* bash compat */
}
arg_path = NULL;
if (!strchr(filename, '/')) {
arg_path = find_in_path(filename);
if (arg_path)
filename = arg_path;
}
input = fopen_or_warn(filename, "r");
free(arg_path);
if (!input) {
/* bb_perror_msg("%s", *argv); - done by fopen_or_warn */
return EXIT_FAILURE;
}
close_on_exec_on(fileno(input));
#if ENABLE_HUSH_FUNCTIONS
sv_flg = G.flag_return_in_progress;
/* "we are inside sourced file, ok to use return" */
G.flag_return_in_progress = -1;
#endif
save_and_replace_G_args(&sv, argv);
parse_and_run_file(input);
fclose(input);
restore_G_args(&sv, argv);
#if ENABLE_HUSH_FUNCTIONS
G.flag_return_in_progress = sv_flg;
#endif
return G.last_exitcode;
}
static int FAST_FUNC builtin_umask(char **argv)
{
int rc;
mode_t mask;
mask = umask(0);
argv = skip_dash_dash(argv);
if (argv[0]) {
mode_t old_mask = mask;
mask ^= 0777;
rc = bb_parse_mode(argv[0], &mask);
mask ^= 0777;
if (rc == 0) {
mask = old_mask;
/* bash messages:
* bash: umask: 'q': invalid symbolic mode operator
* bash: umask: 999: octal number out of range
*/
bb_error_msg("%s: invalid mode '%s'", "umask", argv[0]);
}
} else {
rc = 1;
/* Mimic bash */
printf("%04o\n", (unsigned) mask);
/* fall through and restore mask which we set to 0 */
}
umask(mask);
return !rc; /* rc != 0 - success */
}
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#unset */
static int FAST_FUNC builtin_unset(char **argv)
{
int ret;
unsigned opts;
/* "!": do not abort on errors */
/* "+": stop at 1st non-option */
opts = getopt32(argv, "!+vf");
if (opts == (unsigned)-1)
return EXIT_FAILURE;
if (opts == 3) {
bb_error_msg("unset: -v and -f are exclusive");
return EXIT_FAILURE;
}
argv += optind;
ret = EXIT_SUCCESS;
while (*argv) {
if (!(opts & 2)) { /* not -f */
if (unset_local_var(*argv)) {
/* unset <nonexistent_var> doesn't fail.
* Error is when one tries to unset RO var.
* Message was printed by unset_local_var. */
ret = EXIT_FAILURE;
}
}
#if ENABLE_HUSH_FUNCTIONS
else {
unset_func(*argv);
}
#endif
argv++;
}
return ret;
}
/* http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html */
static int FAST_FUNC builtin_wait(char **argv)
{
int ret = EXIT_SUCCESS;
int status;
argv = skip_dash_dash(argv);
if (argv[0] == NULL) {
/* Don't care about wait results */
/* Note 1: must wait until there are no more children */
/* Note 2: must be interruptible */
/* Examples:
* $ sleep 3 & sleep 6 & wait
* [1] 30934 sleep 3
* [2] 30935 sleep 6
* [1] Done sleep 3
* [2] Done sleep 6
* $ sleep 3 & sleep 6 & wait
* [1] 30936 sleep 3
* [2] 30937 sleep 6
* [1] Done sleep 3
* ^C <-- after ~4 sec from keyboard
* $
*/
while (1) {
int sig;
sigset_t oldset, allsigs;
/* waitpid is not interruptible by SA_RESTARTed
* signals which we use. Thus, this ugly dance:
*/
/* Make sure possible SIGCHLD is stored in kernel's
* pending signal mask before we call waitpid.
* Or else we may race with SIGCHLD, lose it,
* and get stuck in sigwaitinfo...
*/
sigfillset(&allsigs);
sigprocmask(SIG_SETMASK, &allsigs, &oldset);
if (!sigisemptyset(&G.pending_set)) {
/* Crap! we raced with some signal! */
// sig = 0;
goto restore;
}
checkjobs(NULL); /* waitpid(WNOHANG) inside */
if (errno == ECHILD) {
sigprocmask(SIG_SETMASK, &oldset, NULL);
break;
}
/* Wait for SIGCHLD or any other signal */
//sig = sigwaitinfo(&allsigs, NULL);
/* It is vitally important for sigsuspend that SIGCHLD has non-DFL handler! */
/* Note: sigsuspend invokes signal handler */
sigsuspend(&oldset);
restore:
sigprocmask(SIG_SETMASK, &oldset, NULL);
/* So, did we get a signal? */
//if (sig > 0)
// raise(sig); /* run handler */
sig = check_and_run_traps();
if (sig /*&& sig != SIGCHLD - always true */) {
/* see note 2 */
ret = 128 + sig;
break;
}
/* SIGCHLD, or no signal, or ignored one, such as SIGQUIT. Repeat */
}
return ret;
}
/* This is probably buggy wrt interruptible-ness */
while (*argv) {
pid_t pid = bb_strtou(*argv, NULL, 10);
if (errno) {
/* mimic bash message */
bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
return EXIT_FAILURE;
}
if (waitpid(pid, &status, 0) == pid) {
if (WIFSIGNALED(status))
ret = 128 + WTERMSIG(status);
else if (WIFEXITED(status))
ret = WEXITSTATUS(status);
else /* wtf? */
ret = EXIT_FAILURE;
} else {
bb_perror_msg("wait %s", *argv);
ret = 127;
}
argv++;
}
return ret;
}
#if ENABLE_HUSH_LOOPS || ENABLE_HUSH_FUNCTIONS
static unsigned parse_numeric_argv1(char **argv, unsigned def, unsigned def_min)
{
if (argv[1]) {
def = bb_strtou(argv[1], NULL, 10);
if (errno || def < def_min || argv[2]) {
bb_error_msg("%s: bad arguments", argv[0]);
def = UINT_MAX;
}
}
return def;
}
#endif
#if ENABLE_HUSH_LOOPS
static int FAST_FUNC builtin_break(char **argv)
{
unsigned depth;
if (G.depth_of_loop == 0) {
bb_error_msg("%s: only meaningful in a loop", argv[0]);
return EXIT_SUCCESS; /* bash compat */
}
G.flag_break_continue++; /* BC_BREAK = 1 */
G.depth_break_continue = depth = parse_numeric_argv1(argv, 1, 1);
if (depth == UINT_MAX)
G.flag_break_continue = BC_BREAK;
if (G.depth_of_loop < depth)
G.depth_break_continue = G.depth_of_loop;
return EXIT_SUCCESS;
}
static int FAST_FUNC builtin_continue(char **argv)
{
G.flag_break_continue = 1; /* BC_CONTINUE = 2 = 1+1 */
return builtin_break(argv);
}
#endif
#if ENABLE_HUSH_FUNCTIONS
static int FAST_FUNC builtin_return(char **argv)
{
int rc;
if (G.flag_return_in_progress != -1) {
bb_error_msg("%s: not in a function or sourced script", argv[0]);
return EXIT_FAILURE; /* bash compat */
}
G.flag_return_in_progress = 1;
/* bash:
* out of range: wraps around at 256, does not error out
* non-numeric param:
* f() { false; return qwe; }; f; echo $?
* bash: return: qwe: numeric argument required <== we do this
* 255 <== we also do this
*/
rc = parse_numeric_argv1(argv, G.last_exitcode, 0);
return rc;
}
#endif
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