/* vi: set sw=4 ts=4: */ /* * sh.c -- 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 * * 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 * written by Erik Andersen . 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: * b_addchr() derived from similar w_addchar function in glibc-2.2 * setup_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. * * Bash grammar not implemented: (how many of these were in original sh?) * $@ (those sure look like weird quoting rules) * $_ * ! negation operator for pipes * &> and >& redirection of stdout+stderr * Brace Expansion * Tilde Expansion * fancy forms of Parameter Expansion * aliases * Arithmetic Expansion * <(list) and >(list) Process Substitution * reserved words: case, esac, select, function * Here Documents ( << word ) * Functions * Major bugs: * job handling woefully incomplete and buggy (improved --vda) * reserved word execution woefully incomplete and buggy * to-do: * port selected bugfixes from post-0.49 busybox lash - done? * finish implementing reserved words: for, while, until, do, done * change { and } from special chars to reserved words * builtins: break, continue, eval, return, set, trap, ulimit * test magic exec * handle children going into background * clean up recognition of null pipes * check setting of global_argc and global_argv * control-C handling, probably with longjmp * follow IFS rules more precisely, including update semantics * figure out what to do with backslash-newline * explain why we use signal instead of sigaction * propagate syntax errors, die on resource errors? * continuation lines, both explicit and implicit - done? * memory leak finding and plugging - done? * more testing, especially quoting rules and redirection * document how quoting rules not precisely followed for variable assignments * maybe change map[] to use 2-bit entries * (eventually) remove all the printf's * * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. */ #include "busybox.h" #include /* glob, of course */ #include /* should be pretty obvious */ /* #include */ //#define DEBUG_SHELL /* Finer-grained debug switch */ //#define DEBUG_SHELL_JOBS //#define DEBUG_SHELL_EXECUTION #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 #define SPECIAL_VAR_SYMBOL 03 #define FLAG_EXIT_FROM_LOOP 1 #define FLAG_PARSE_SEMICOLON (1 << 1) /* symbol ';' is special for parser */ #define FLAG_REPARSING (1 << 2) /* >=2nd pass */ typedef enum { REDIRECT_INPUT = 1, REDIRECT_OVERWRITE = 2, REDIRECT_APPEND = 3, REDIRECT_HEREIS = 4, REDIRECT_IO = 5 } redir_type; /* 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[] = { { 0, 0, "()" }, { O_RDONLY, 0, "<" }, { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" }, { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" }, { O_RDONLY, -1, "<<" }, { O_RDWR, 1, "<>" } }; typedef enum { PIPE_SEQ = 1, PIPE_AND = 2, PIPE_OR = 3, PIPE_BG = 4, } pipe_style; /* might eventually control execution */ typedef enum { RES_NONE = 0, RES_IF = 1, RES_THEN = 2, RES_ELIF = 3, RES_ELSE = 4, RES_FI = 5, RES_FOR = 6, RES_WHILE = 7, RES_UNTIL = 8, RES_DO = 9, RES_DONE = 10, RES_XXXX = 11, RES_IN = 12, RES_SNTX = 13 } reserved_style; enum { FLAG_END = (1 << RES_NONE ), 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 ), 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 ), FLAG_START = (1 << RES_XXXX ), }; /* This holds pointers to the various results of parsing */ struct p_context { struct child_prog *child; struct pipe *list_head; struct pipe *pipe; struct redir_struct *pending_redirect; reserved_style w; int old_flag; /* for figuring out valid reserved words */ struct p_context *stack; int type; /* define type of parser : ";$" common or special symbol */ /* How about quoting status? */ }; struct redir_struct { struct redir_struct *next; /* pointer to the next redirect in the list */ redir_type type; /* type of redirection */ int fd; /* file descriptor being redirected */ int dup; /* -1, or file descriptor being duplicated */ glob_t word; /* *word.gl_pathv is the filename */ }; struct child_prog { pid_t pid; /* 0 if exited */ char **argv; /* program name and arguments */ struct pipe *group; /* if non-NULL, first in group or subshell */ int subshell; /* flag, non-zero if group must be forked */ struct redir_struct *redirects; /* I/O redirections */ glob_t glob_result; /* result of parameter globbing */ int is_stopped; /* is the program currently running? */ struct pipe *family; /* pointer back to the child's parent pipe */ int sp; /* number of SPECIAL_VAR_SYMBOL */ int type; }; struct pipe { struct pipe *next; int num_progs; /* total number of programs in job */ int running_progs; /* number of programs running (not exited) */ char *cmdbuf; /* buffer various argv's point into */ #if ENABLE_HUSH_JOB int jobid; /* job number */ char *cmdtext; /* name of job */ pid_t pgrp; /* process group ID for the job */ #endif struct child_prog *progs; /* array of commands in pipe */ int stopped_progs; /* number of programs alive, but stopped */ int job_context; /* bitmask defining current context */ pipe_style followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */ reserved_style r_mode; /* supports if, for, while, until */ }; struct close_me { struct close_me *next; int fd; }; struct variables { struct variables *next; const char *name; const char *value; int flg_export; int flg_read_only; }; /* globals, connect us to the outside world * the first three support $?, $#, and $1 */ static char **global_argv; static int global_argc; static int last_return_code; extern char **environ; /* This is in , but protected with __USE_GNU */ /* "globals" within this file */ static const char *ifs; static unsigned char map[256]; static int fake_mode; static struct close_me *close_me_head; static const char *cwd; static unsigned last_bg_pid; #if !ENABLE_HUSH_INTERACTIVE enum { interactive_fd = 0 }; #else /* 'interactive_fd' is a fd# open to ctty, if we have one * _AND_ if we decided to mess with job control */ static int interactive_fd; #if ENABLE_HUSH_JOB static pid_t saved_task_pgrp; static pid_t saved_tty_pgrp; static int last_jobid; static struct pipe *job_list; #endif static const char *PS1; static const char *PS2; #endif #define HUSH_VER_STR "0.02" static struct variables shell_ver = { NULL, "HUSH_VERSION", HUSH_VER_STR, 1, 1 }; static struct variables *top_vars = &shell_ver; #define B_CHUNK 100 #define B_NOSPAC 1 typedef struct { char *data; int length; int maxlen; int quote; int nonnull; } o_string; #define NULL_O_STRING {NULL,0,0,0,0} /* used for initialization: o_string foo = NULL_O_STRING; */ /* I can almost use ordinary FILE *. Is open_memstream() universally * available? Where is it documented? */ struct in_str { const char *p; char peek_buf[2]; #if ENABLE_HUSH_INTERACTIVE int __promptme; int promptmode; #endif FILE *file; int (*get) (struct in_str *); int (*peek) (struct in_str *); }; #define b_getch(input) ((input)->get(input)) #define b_peek(input) ((input)->peek(input)) #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n" struct built_in_command { const char *cmd; /* name */ const char *descr; /* description */ int (*function) (char **argv); /* function ptr */ }; #ifdef DEBUG_SHELL #define debug_printf(...) fprintf(stderr, __VA_ARGS__) /* broken, of course, but OK for testing */ static char *indenter(int i) { static char blanks[] = " "; return &blanks[sizeof(blanks) - i - 1]; } #else #define debug_printf(...) do {} while (0) #endif #ifdef DEBUG_SHELL_JOBS #define debug_jobs_printf(...) fprintf(stderr, __VA_ARGS__) #else #define debug_jobs_printf(...) do {} while (0) #endif #ifdef DEBUG_SHELL_EXECUTION #define debug_exec_printf(...) fprintf(stderr, __VA_ARGS__) #else #define debug_exec_printf(...) do {} while (0) #endif #define final_printf debug_printf static void __syntax(int line) { bb_error_msg("syntax error hush.c:%d", line); } #define syntax() __syntax(__LINE__) /* Index of subroutines: */ /* function prototypes for builtins */ static int builtin_cd(char **argv); static int builtin_env(char **argv); static int builtin_eval(char **argv); static int builtin_exec(char **argv); static int builtin_exit(char **argv); static int builtin_export(char **argv); #if ENABLE_HUSH_JOB static int builtin_fg_bg(char **argv); static int builtin_jobs(char **argv); #endif static int builtin_help(char **argv); static int builtin_pwd(char **argv); static int builtin_read(char **argv); static int builtin_set(char **argv); static int builtin_shift(char **argv); static int builtin_source(char **argv); static int builtin_umask(char **argv); static int builtin_unset(char **argv); static int builtin_not_written(char **argv); /* o_string manipulation: */ static int b_check_space(o_string *o, int len); static int b_addchr(o_string *o, int ch); static void b_reset(o_string *o); static int b_addqchr(o_string *o, int ch, int quote); static int b_adduint(o_string *o, unsigned i); /* in_str manipulations: */ static int static_get(struct in_str *i); static int static_peek(struct in_str *i); static int file_get(struct in_str *i); static int file_peek(struct in_str *i); static void setup_file_in_str(struct in_str *i, FILE *f); static void setup_string_in_str(struct in_str *i, const char *s); /* close_me manipulations: */ static void mark_open(int fd); static void mark_closed(int fd); static void close_all(void); /* "run" the final data structures: */ static int free_pipe_list(struct pipe *head, int indent); static int free_pipe(struct pipe *pi, int indent); /* really run the final data structures: */ static int setup_redirects(struct child_prog *prog, int squirrel[]); static int run_list_real(struct pipe *pi); static void pseudo_exec_argv(char **argv) ATTRIBUTE_NORETURN; static void pseudo_exec(struct child_prog *child) ATTRIBUTE_NORETURN; static int run_pipe_real(struct pipe *pi); /* extended glob support: */ static int globhack(const char *src, int flags, glob_t *pglob); static int glob_needed(const char *s); static int xglob(o_string *dest, int flags, glob_t *pglob); /* variable assignment: */ static int is_assignment(const char *s); /* data structure manipulation: */ static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input); static void initialize_context(struct p_context *ctx); static int done_word(o_string *dest, struct p_context *ctx); static int done_command(struct p_context *ctx); static int done_pipe(struct p_context *ctx, pipe_style type); /* primary string parsing: */ static int redirect_dup_num(struct in_str *input); static int redirect_opt_num(o_string *o); static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end); static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch); static const char *lookup_param(const char *src); static char *make_string(char **inp); static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input); static int parse_string(o_string *dest, struct p_context *ctx, const char *src); static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger); /* setup: */ static int parse_stream_outer(struct in_str *inp, int flag); static int parse_string_outer(const char *s, int flag); static int parse_file_outer(FILE *f); /* job management: */ static int checkjobs(struct pipe* fg_pipe); #if ENABLE_HUSH_JOB static int checkjobs_and_fg_shell(struct pipe* fg_pipe); static void insert_bg_job(struct pipe *pi); static void remove_bg_job(struct pipe *pi); static void delete_finished_bg_job(struct pipe *pi); #else int checkjobs_and_fg_shell(struct pipe* fg_pipe); /* never called */ #endif /* local variable support */ static char **make_list_in(char **inp, char *name); static char *insert_var_value(char *inp); static const char *get_local_var(const char *var); static int set_local_var(const char *s, int flg_export); static void unset_local_var(const char *name); /* 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. */ static const struct built_in_command bltins[] = { #if ENABLE_HUSH_JOB { "bg", "Resume a job in the background", builtin_fg_bg }, #endif { "break", "Exit for, while or until loop", builtin_not_written }, { "cd", "Change working directory", builtin_cd }, { "continue", "Continue for, while or until loop", builtin_not_written }, { "env", "Print all environment variables", builtin_env }, { "eval", "Construct and run shell command", builtin_eval }, { "exec", "Exec command, replacing this shell with the exec'd process", builtin_exec }, { "exit", "Exit from shell()", builtin_exit }, { "export", "Set environment variable", builtin_export }, #if ENABLE_HUSH_JOB { "fg", "Bring job into the foreground", builtin_fg_bg }, { "jobs", "Lists the active jobs", builtin_jobs }, #endif { "pwd", "Print current directory", builtin_pwd }, { "read", "Input environment variable", builtin_read }, { "return", "Return from a function", builtin_not_written }, { "set", "Set/unset shell local variables", builtin_set }, { "shift", "Shift positional parameters", builtin_shift }, { "trap", "Trap signals", builtin_not_written }, { "ulimit","Controls resource limits", builtin_not_written }, { "umask","Sets file creation mask", builtin_umask }, { "unset", "Unset environment variable", builtin_unset }, { ".", "Source-in and run commands in a file", builtin_source }, { "help", "List shell built-in commands", builtin_help }, { NULL, NULL, NULL } }; #if ENABLE_HUSH_JOB #if ENABLE_FEATURE_SH_STANDALONE /* move to libbb? */ static void signal_SA_RESTART(int sig, void (*handler)(int)) { struct sigaction sa; sa.sa_handler = handler; sa.sa_flags = SA_RESTART; sigemptyset(&sa.sa_mask); sigaction(sig, &sa, NULL); } #endif /* Signals are grouped, we handle them in batches */ static void set_fatal_sighandler(void (*handler)(int)) { signal(SIGILL , handler); signal(SIGTRAP, handler); signal(SIGABRT, handler); signal(SIGFPE , handler); signal(SIGBUS , handler); signal(SIGSEGV, handler); /* bash 3.2 seems to handle these just like 'fatal' ones */ signal(SIGHUP , handler); signal(SIGPIPE, handler); signal(SIGALRM, handler); } static void set_jobctrl_sighandler(void (*handler)(int)) { signal(SIGTSTP, handler); signal(SIGTTIN, handler); signal(SIGTTOU, handler); } static void set_misc_sighandler(void (*handler)(int)) { signal(SIGINT , handler); signal(SIGQUIT, handler); signal(SIGTERM, handler); } /* SIGCHLD is special and handled separately */ #if ENABLE_FEATURE_SH_STANDALONE static void set_every_sighandler(void (*handler)(int)) { set_fatal_sighandler(handler); set_jobctrl_sighandler(handler); set_misc_sighandler(handler); signal(SIGCHLD, handler); } static struct pipe *nofork_pipe; struct nofork_save_area nofork_save; static sigjmp_buf nofork_jb; static void handler_ctrl_c(int sig) { debug_jobs_printf("got sig %d\n", sig); // as usual we can have all kinds of nasty problems with leaked malloc data here siglongjmp(nofork_jb, 1); } static void handler_ctrl_z(int sig) { pid_t pid; debug_jobs_printf("got tty sig %d\n", sig); pid = fork(); if (pid < 0) /* can't fork. Pretend there were no Ctrl-Z */ return; debug_jobs_printf("bg'ing nofork\n"); nofork_save.saved = 0; /* flag the fact that Ctrl-Z was handled */ nofork_pipe->running_progs = 1; nofork_pipe->stopped_progs = 0; if (!pid) { /* child */ debug_jobs_printf("setting pgrp for child\n"); setpgrp(); set_every_sighandler(SIG_DFL); raise(SIGTSTP); /* resend TSTP so that child will be stopped */ debug_jobs_printf("returning to child\n"); /* return to nofork, it will eventually exit now, * not return back to shell */ return; } /* parent */ /* finish filling up pipe info */ nofork_pipe->pgrp = pid; /* child is in its own pgrp */ nofork_pipe->progs[0].pid = pid; nofork_pipe->running_progs = 1; nofork_pipe->stopped_progs = 0; /* parent needs to longjmp out of running nofork. * we will "return" exitcode 0, with child put in background */ // as usual we can have all kinds of nasty problems with leaked malloc data here siglongjmp(nofork_jb, 1); } #endif /* Restores tty foreground process group, and exits. * May be called as signal handler for fatal signal * (will faithfully 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) ATTRIBUTE_NORETURN; static void sigexit(int sig) { sigset_t block_all; /* Disable all signals: job control, SIGPIPE, etc. */ sigfillset(&block_all); sigprocmask(SIG_SETMASK, &block_all, NULL); if (interactive_fd) tcsetpgrp(interactive_fd, saved_tty_pgrp); /* Not a signal, just exit */ if (sig <= 0) _exit(- sig); /* Enable only this sig and kill ourself with it */ signal(sig, SIG_DFL); sigdelset(&block_all, sig); sigprocmask(SIG_SETMASK, &block_all, NULL); raise(sig); _exit(1); /* Should not reach it */ } /* Restores tty foreground process group, and exits. */ static void hush_exit(int exitcode) ATTRIBUTE_NORETURN; static void hush_exit(int exitcode) { fflush(NULL); /* flush all streams */ sigexit(- (exitcode & 0xff)); } #else /* !JOB */ #define set_fatal_sighandler(handler) ((void)0) #define set_jobctrl_sighandler(handler) ((void)0) #define set_misc_sighandler(handler) ((void)0) #define hush_exit(e) exit(e) #endif /* JOB */ static const char *set_cwd(void) { if (cwd == bb_msg_unknown) cwd = NULL; /* xrealloc_getcwd_or_warn(arg) calls free(arg)! */ cwd = xrealloc_getcwd_or_warn((char *)cwd); if (!cwd) cwd = bb_msg_unknown; return cwd; } /* built-in 'eval' handler */ static int builtin_eval(char **argv) { char *str = NULL; int rcode = EXIT_SUCCESS; if (argv[1]) { str = make_string(argv + 1); parse_string_outer(str, FLAG_EXIT_FROM_LOOP | FLAG_PARSE_SEMICOLON); free(str); rcode = last_return_code; } return rcode; } /* built-in 'cd ' handler */ static int builtin_cd(char **argv) { char *newdir; if (argv[1] == NULL) newdir = getenv("HOME"); else newdir = argv[1]; if (chdir(newdir)) { printf("cd: %s: %s\n", newdir, strerror(errno)); return EXIT_FAILURE; } set_cwd(); return EXIT_SUCCESS; } /* built-in 'env' handler */ static int builtin_env(char **argv ATTRIBUTE_UNUSED) { /* TODO: call env applet's code instead */ char **e = environ; if (e == NULL) return EXIT_FAILURE; while (*e) { puts(*e++); } return EXIT_SUCCESS; } /* built-in 'exec' handler */ static int builtin_exec(char **argv) { if (argv[1] == NULL) return EXIT_SUCCESS; /* Really? */ pseudo_exec_argv(argv + 1); /* never returns */ } /* built-in 'exit' handler */ static int builtin_exit(char **argv) { // TODO: bash does it ONLY on top-level sh exit (+interacive only?) //puts("exit"); /* bash does it */ if (argv[1] == NULL) hush_exit(last_return_code); /* mimic bash: exit 123abc == exit 255 + error msg */ xfunc_error_retval = 255; /* bash: exit -2 == exit 254, no error msg */ hush_exit(xatoi(argv[1])); } /* built-in 'export VAR=value' handler */ static int builtin_export(char **argv) { int res = 0; char *name = argv[1]; if (name == NULL) { return builtin_env(argv); } name = strdup(name); if (name) { const char *value = strchr(name, '='); if (!value) { char *tmp; /* They are exporting something without an =VALUE */ value = get_local_var(name); if (value) { size_t ln = strlen(name); tmp = realloc(name, ln+strlen(value)+2); if (tmp == NULL) res = -1; else { sprintf(tmp+ln, "=%s", value); name = tmp; } } else { /* bash does not return an error when trying to export * an undefined variable. Do likewise. */ res = 1; } } } if (res < 0) bb_perror_msg("export"); else if (res == 0) res = set_local_var(name, 1); else res = 0; free(name); return res; } #if ENABLE_HUSH_JOB /* built-in 'fg' and 'bg' handler */ static int builtin_fg_bg(char **argv) { int i, jobnum; struct pipe *pi; if (!interactive_fd) return EXIT_FAILURE; /* If they gave us no args, assume they want the last backgrounded task */ if (!argv[1]) { for (pi = job_list; pi; pi = pi->next) { if (pi->jobid == 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 = 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] == 'f') { /* Put the job into the foreground. */ tcsetpgrp(interactive_fd, pi->pgrp); } /* Restart the processes in the job */ debug_jobs_printf("reviving %d procs, pgrp %d\n", pi->num_progs, pi->pgrp); for (i = 0; i < pi->num_progs; i++) { debug_jobs_printf("reviving pid %d\n", pi->progs[i].pid); pi->progs[i].is_stopped = 0; } pi->stopped_progs = 0; i = kill(- pi->pgrp, SIGCONT); if (i < 0) { if (errno == ESRCH) { delete_finished_bg_job(pi); return EXIT_SUCCESS; } else { bb_perror_msg("kill (SIGCONT)"); } } if (*argv[0] == 'f') { remove_bg_job(pi); return checkjobs_and_fg_shell(pi); } return EXIT_SUCCESS; } #endif /* built-in 'help' handler */ static int builtin_help(char **argv ATTRIBUTE_UNUSED) { const struct built_in_command *x; printf("\nBuilt-in commands:\n"); printf("-------------------\n"); for (x = bltins; x->cmd; x++) { if (x->descr == NULL) continue; printf("%s\t%s\n", x->cmd, x->descr); } printf("\n\n"); return EXIT_SUCCESS; } #if ENABLE_HUSH_JOB /* built-in 'jobs' handler */ static int builtin_jobs(char **argv ATTRIBUTE_UNUSED) { struct pipe *job; const char *status_string; for (job = job_list; job; job = job->next) { if (job->running_progs == job->stopped_progs) status_string = "Stopped"; else status_string = "Running"; printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext); } return EXIT_SUCCESS; } #endif /* built-in 'pwd' handler */ static int builtin_pwd(char **argv ATTRIBUTE_UNUSED) { puts(set_cwd()); return EXIT_SUCCESS; } /* built-in 'read VAR' handler */ static int builtin_read(char **argv) { int res; if (argv[1]) { char string[BUFSIZ]; char *var = NULL; string[0] = '\0'; /* In case stdin has only EOF */ /* read string */ fgets(string, sizeof(string), stdin); chomp(string); var = malloc(strlen(argv[1]) + strlen(string) + 2); if (var) { sprintf(var, "%s=%s", argv[1], string); res = set_local_var(var, 0); } else res = -1; if (res) bb_perror_msg("read"); free(var); /* So not move up to avoid breaking errno */ return res; } do res = getchar(); while (res != '\n' && res != EOF); return 0; } /* built-in 'set VAR=value' handler */ static int builtin_set(char **argv) { char *temp = argv[1]; struct variables *e; if (temp == NULL) for (e = top_vars; e; e = e->next) printf("%s=%s\n", e->name, e->value); else set_local_var(temp, 0); return EXIT_SUCCESS; } /* Built-in 'shift' handler */ static int builtin_shift(char **argv) { int n = 1; if (argv[1]) { n = atoi(argv[1]); } if (n >= 0 && n < global_argc) { /* XXX This probably breaks $0 */ global_argc -= n; global_argv += n; return EXIT_SUCCESS; } return EXIT_FAILURE; } /* Built-in '.' handler (read-in and execute commands from file) */ static int builtin_source(char **argv) { FILE *input; int status; if (argv[1] == NULL) return EXIT_FAILURE; /* XXX search through $PATH is missing */ input = fopen(argv[1], "r"); if (!input) { bb_error_msg("cannot open '%s'", argv[1]); return EXIT_FAILURE; } /* Now run the file */ /* XXX argv and argc are broken; need to save old global_argv * (pointer only is OK!) on this stack frame, * set global_argv=argv+1, recurse, and restore. */ mark_open(fileno(input)); status = parse_file_outer(input); mark_closed(fileno(input)); fclose(input); return status; } static int builtin_umask(char **argv) { mode_t new_umask; const char *arg = argv[1]; char *end; if (arg) { new_umask = strtoul(arg, &end, 8); if (*end != '\0' || end == arg) { return EXIT_FAILURE; } } else { new_umask = umask(0); printf("%.3o\n", (unsigned) new_umask); } umask(new_umask); return EXIT_SUCCESS; } /* built-in 'unset VAR' handler */ static int builtin_unset(char **argv) { /* bash returned already true */ unset_local_var(argv[1]); return EXIT_SUCCESS; } static int builtin_not_written(char **argv) { printf("builtin_%s not written\n", argv[0]); return EXIT_FAILURE; } static int b_check_space(o_string *o, int len) { /* It would be easy to drop a more restrictive policy * in here, such as setting a maximum string length */ if (o->length + len > o->maxlen) { char *old_data = o->data; /* assert(data == NULL || o->maxlen != 0); */ o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK); o->data = realloc(o->data, 1 + o->maxlen); if (o->data == NULL) { free(old_data); } } return o->data == NULL; } static int b_addchr(o_string *o, int ch) { debug_printf("b_addchr: %c %d %p\n", ch, o->length, o); if (b_check_space(o, 1)) return B_NOSPAC; o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; return 0; } static void b_reset(o_string *o) { o->length = 0; o->nonnull = 0; if (o->data != NULL) *o->data = '\0'; } static void b_free(o_string *o) { b_reset(o); free(o->data); o->data = NULL; o->maxlen = 0; } /* My analysis of quoting semantics tells me that state information * is associated with a destination, not a source. */ static int b_addqchr(o_string *o, int ch, int quote) { if (quote && strchr("*?[\\", ch)) { int rc; rc = b_addchr(o, '\\'); if (rc) return rc; } return b_addchr(o, ch); } static int b_adduint(o_string *o, unsigned i) { int r; char buf[sizeof(unsigned)*3 + 1]; char *p = buf; *(utoa_to_buf(i, buf, sizeof(buf))) = '\0'; /* no escape checking necessary */ do r = b_addchr(o, *p++); while (r == 0 && *p); return r; } static int static_get(struct in_str *i) { int ch = *i->p++; if (ch == '\0') return EOF; return ch; } static int static_peek(struct in_str *i) { return *i->p; } #if ENABLE_HUSH_INTERACTIVE static void cmdedit_set_initial_prompt(void) { #if !ENABLE_FEATURE_EDITING_FANCY_PROMPT PS1 = NULL; #else PS1 = getenv("PS1"); if (PS1 == NULL) PS1 = "\\w \\$ "; #endif } 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 == 1) { char *ns; free((char*)PS1); ns = xmalloc(strlen(cwd)+4); sprintf(ns, "%s %s", cwd, (geteuid() != 0) ? "$ " : "# "); prompt_str = ns; PS1 = ns; } else { prompt_str = PS2; } #else prompt_str = (promptmode == 1) ? PS1 : PS2; #endif debug_printf("result %s\n", prompt_str); return prompt_str; } #endif #if ENABLE_FEATURE_EDITING static line_input_t *line_input_state; #endif #if ENABLE_HUSH_INTERACTIVE static int get_user_input(struct in_str *i) { static char the_command[ENABLE_FEATURE_EDITING ? BUFSIZ : 2]; 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; otherwise, we'll end up bequeathing ** atexit() handlers and other unwanted stuff to our ** child processes (rob@sysgo.de) */ r = read_line_input(prompt_str, the_command, BUFSIZ, line_input_state); #else fputs(prompt_str, stdout); fflush(stdout); the_command[0] = r = fgetc(i->file); the_command[1] = '\0'; #endif fflush(stdout); i->p = the_command; return r; /* < 0 == EOF. Not meaningful otherwise */ } #endif /* This is the magic location that prints prompts * and gets data back from the user */ static int file_get(struct in_str *i) { int ch; ch = 0; /* If there is data waiting, eat it up */ if (i->p && *i->p) { ch = *i->p++; } 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 (interactive_fd && i->__promptme && i->file == stdin) { while (!i->p || !(interactive_fd && i->p[0])) { if (get_user_input(i) < 0) return EOF; } i->promptmode = 2; i->__promptme = 0; if (i->p && *i->p) { ch = *i->p++; } } else #endif { ch = fgetc(i->file); } debug_printf("b_getch: got a %d\n", ch); } #if ENABLE_HUSH_INTERACTIVE if (ch == '\n') i->__promptme = 1; #endif return ch; } /* All the callers guarantee this routine will never be * used right after a newline, so prompting is not needed. */ static int file_peek(struct in_str *i) { if (i->p && *i->p) { return *i->p; } i->peek_buf[0] = fgetc(i->file); i->peek_buf[1] = '\0'; i->p = i->peek_buf; debug_printf("b_peek: got a %d\n", *i->p); return *i->p; } static void setup_file_in_str(struct in_str *i, FILE *f) { i->peek = file_peek; i->get = file_get; #if ENABLE_HUSH_INTERACTIVE i->__promptme = 1; i->promptmode = 1; #endif i->file = f; i->p = NULL; } static void setup_string_in_str(struct in_str *i, const char *s) { i->peek = static_peek; i->get = static_get; #if ENABLE_HUSH_INTERACTIVE i->__promptme = 1; i->promptmode = 1; #endif i->p = s; } static void mark_open(int fd) { struct close_me *new = xmalloc(sizeof(struct close_me)); new->fd = fd; new->next = close_me_head; close_me_head = new; } static void mark_closed(int fd) { struct close_me *tmp; if (close_me_head == NULL || close_me_head->fd != fd) bb_error_msg_and_die("corrupt close_me"); tmp = close_me_head; close_me_head = close_me_head->next; free(tmp); } static void close_all(void) { struct close_me *c; for (c = close_me_head; c; c = c->next) { close(c->fd); } close_me_head = NULL; } /* squirrel != NULL means we squirrel away copies of stdin, stdout, * and stderr if they are redirected. */ static int setup_redirects(struct child_prog *prog, int squirrel[]) { int openfd, mode; struct redir_struct *redir; for (redir = prog->redirects; redir; redir = redir->next) { if (redir->dup == -1 && redir->word.gl_pathv == NULL) { /* something went wrong in the parse. Pretend it didn't happen */ continue; } if (redir->dup == -1) { mode = redir_table[redir->type].mode; openfd = open_or_warn(redir->word.gl_pathv[0], mode); 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!) */ return 1; } } else { openfd = redir->dup; } if (openfd != redir->fd) { if (squirrel && redir->fd < 3) { squirrel[redir->fd] = dup(redir->fd); } if (openfd == -3) { close(openfd); } else { dup2(openfd, redir->fd); if (redir->dup == -1) 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) { /* No error checking. I sure wouldn't know what * to do with an error if I found one! */ dup2(fd, i); close(fd); } } } /* never returns */ /* XXX no 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(char **argv) { int i, rcode; char *p; const struct built_in_command *x; for (i = 0; is_assignment(argv[i]); i++) { debug_printf("pid %d environment modification: %s\n", getpid(), argv[i]); // FIXME: vfork case?? p = insert_var_value(argv[i]); putenv(strdup(p)); if (p != argv[i]) free(p); } argv += i; /* If a variable is assigned in a forest, and nobody listens, * was it ever really set? */ if (argv[0] == NULL) { _exit(EXIT_SUCCESS); } /* * 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. */ for (x = bltins; x->cmd; x++) { if (strcmp(argv[0], x->cmd) == 0) { debug_printf("builtin exec %s\n", argv[0]); rcode = x->function(argv); fflush(stdout); _exit(rcode); } } /* Check if the command matches any busybox internal commands * ("applets") here. * FIXME: This feature is not 100% safe, since * BusyBox is not fully reentrant, so we have no guarantee the things * from the .bss are still zeroed, or that things from .data are still * at their defaults. We could exec ourself from /proc/self/exe, but I * really dislike relying on /proc for things. We could exec ourself * from global_argv[0], but if we are in a chroot, we may not be able * to find ourself... */ #if ENABLE_FEATURE_SH_STANDALONE debug_printf("running applet %s\n", argv[0]); run_applet_and_exit(argv[0], argv); // is it ok that run_applet_and_exit() does exit(), not _exit()? // NB: IIRC on NOMMU we are after _vfork_, not fork! #endif debug_printf("exec of %s\n", argv[0]); execvp(argv[0], argv); bb_perror_msg("cannot exec '%s'", argv[0]); _exit(1); } static void pseudo_exec(struct child_prog *child) { int rcode; if (child->argv) { pseudo_exec_argv(child->argv); } if (child->group) { // FIXME: do not modify globals! Think vfork! #if ENABLE_HUSH_INTERACTIVE interactive_fd = 0; /* crucial!!!! */ #endif debug_exec_printf("pseudo_exec: run_list_real\n"); rcode = run_list_real(child->group); /* OK to leak memory by not calling free_pipe_list, * since this process is about to exit */ _exit(rcode); } /* Can happen. See what bash does with ">foo" by itself. */ debug_printf("trying to pseudo_exec 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, , fg, , fg, ...." here...) * On subsequent bg argv can be trashed, but we won't use it */ if (pi->cmdtext) return pi->cmdtext; argv = pi->progs[0].argv; if (!argv || !argv[0]) return (pi->cmdtext = xzalloc(1)); len = 0; do len += strlen(*argv) + 1; while (*++argv); pi->cmdtext = p = xmalloc(len); argv = pi->progs[0].argv; do { len = strlen(*argv); memcpy(p, *argv, len); p += len; *p++ = ' '; } while (*++argv); p[-1] = '\0'; return pi->cmdtext; } #endif #if ENABLE_HUSH_JOB static void insert_bg_job(struct pipe *pi) { struct pipe *thejob; /* Linear search for the ID of the job to use */ pi->jobid = 1; for (thejob = job_list; thejob; thejob = thejob->next) if (thejob->jobid >= pi->jobid) pi->jobid = thejob->jobid + 1; /* add thejob to the list of running jobs */ if (!job_list) { thejob = job_list = xmalloc(sizeof(*thejob)); } else { for (thejob = job_list; thejob->next; thejob = thejob->next) continue; thejob->next = xmalloc(sizeof(*thejob)); thejob = thejob->next; } /* physically copy the struct job */ memcpy(thejob, pi, sizeof(struct pipe)); thejob->progs = xmalloc(sizeof(pi->progs[0]) * pi->num_progs); memcpy(thejob->progs, pi->progs, sizeof(pi->progs[0]) * pi->num_progs); thejob->next = NULL; /*seems to be wrong:*/ /*thejob->running_progs = thejob->num_progs;*/ /*thejob->stopped_progs = 0;*/ thejob->cmdtext = xstrdup(get_cmdtext(pi)); /* we don't wait for background thejobs to return -- append it to the list of backgrounded thejobs and leave it alone */ printf("[%d] %d %s\n", thejob->jobid, thejob->progs[0].pid, thejob->cmdtext); last_bg_pid = thejob->progs[0].pid; last_jobid = thejob->jobid; } static void remove_bg_job(struct pipe *pi) { struct pipe *prev_pipe; if (pi == job_list) { job_list = pi->next; } else { prev_pipe = job_list; while (prev_pipe->next != pi) prev_pipe = prev_pipe->next; prev_pipe->next = pi->next; } if (job_list) last_jobid = job_list->jobid; else last_jobid = 0; } /* remove a backgrounded job */ static void delete_finished_bg_job(struct pipe *pi) { remove_bg_job(pi); pi->stopped_progs = 0; free_pipe(pi, 0); free(pi); } #endif /* Checks 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 int prognum = 0; struct pipe *pi; #endif pid_t childpid; int rcode = 0; attributes = WUNTRACED; if (fg_pipe == NULL) { attributes |= WNOHANG; } /* Do we do this right? * bash-3.00# sleep 20 | false * * [3]+ Stopped sleep 20 | false * bash-3.00# echo $? * 1 <========== bg pipe is not fully done, but exitcode is already known! */ //FIXME: non-interactive bash does not continue even if all processes in fg pipe //are stopped. Testcase: "cat | cat" in a script (not on command line) // + killall -STOP cat wait_more: while ((childpid = waitpid(-1, &status, attributes)) > 0) { const int dead = WIFEXITED(status) || WIFSIGNALED(status); #ifdef DEBUG_SHELL_JOBS if (WIFSTOPPED(status)) debug_jobs_printf("pid %d stopped by sig %d (exitcode %d)\n", childpid, WSTOPSIG(status), WEXITSTATUS(status)); if (WIFSIGNALED(status)) debug_jobs_printf("pid %d killed by sig %d (exitcode %d)\n", childpid, WTERMSIG(status), WEXITSTATUS(status)); if (WIFEXITED(status)) debug_jobs_printf("pid %d exited, exitcode %d\n", childpid, WEXITSTATUS(status)); #endif /* Were we asked to wait for fg pipe? */ if (fg_pipe) { int i; for (i = 0; i < fg_pipe->num_progs; i++) { debug_jobs_printf("check pid %d\n", fg_pipe->progs[i].pid); if (fg_pipe->progs[i].pid == childpid) { /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */ if (dead) { fg_pipe->progs[i].pid = 0; fg_pipe->running_progs--; if (i == fg_pipe->num_progs-1) /* last process gives overall exitstatus */ rcode = WEXITSTATUS(status); } else { fg_pipe->progs[i].is_stopped = 1; fg_pipe->stopped_progs++; } debug_jobs_printf("fg_pipe: running_progs %d stopped_progs %d\n", fg_pipe->running_progs, fg_pipe->stopped_progs); if (fg_pipe->running_progs - fg_pipe->stopped_progs <= 0) { /* All processes in fg pipe have exited/stopped */ #if ENABLE_HUSH_JOB if (fg_pipe->running_progs) insert_bg_job(fg_pipe); #endif return rcode; } /* There are still running processes in the fg pipe */ goto wait_more; } } /* fall through to searching 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 = job_list; pi; pi = pi->next) { prognum = 0; while (prognum < pi->num_progs) { if (pi->progs[prognum].pid == childpid) goto found_pi_and_prognum; prognum++; } } #endif /* Happens when shell is used as init process (init=/bin/sh) */ debug_printf("checkjobs: pid %d was not in our list!\n", childpid); goto wait_more; #if ENABLE_HUSH_JOB found_pi_and_prognum: if (dead) { /* child exited */ pi->progs[prognum].pid = 0; pi->running_progs--; if (!pi->running_progs) { printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->cmdtext); delete_finished_bg_job(pi); } } else { /* child stopped */ pi->stopped_progs++; pi->progs[prognum].is_stopped = 1; } #endif } /* wait found no children or failed */ if (childpid && errno != ECHILD) bb_perror_msg("waitpid"); /* move the shell to the foreground */ //if (interactive_fd && tcsetpgrp(interactive_fd, getpgid(0))) // bb_perror_msg("tcsetpgrp-2"); return rcode; } #if ENABLE_HUSH_JOB static int checkjobs_and_fg_shell(struct pipe* fg_pipe) { pid_t p; int rcode = checkjobs(fg_pipe); /* Job finished, move the shell to the foreground */ p = getpgid(0); debug_printf("fg'ing ourself: getpgid(0)=%d\n", (int)p); if (tcsetpgrp(interactive_fd, p) && errno != ENOTTY) bb_perror_msg("tcsetpgrp-4a"); return rcode; } #endif #if ENABLE_FEATURE_SH_STANDALONE /* run_pipe_real's helper */ static int run_single_fg_nofork(struct pipe *pi, const struct bb_applet *a, char **argv) { #if ENABLE_HUSH_JOB int rcode; /* TSTP handler will store pid etc in pi */ nofork_pipe = pi; save_nofork_data(&nofork_save); if (sigsetjmp(nofork_jb, 1) == 0) { signal_SA_RESTART(SIGTSTP, handler_ctrl_z); signal(SIGINT, handler_ctrl_c); rcode = run_nofork_applet_prime(&nofork_save, a, argv); if (--nofork_save.saved != 0) { /* Ctrl-Z forked, we are child */ exit(rcode); } return rcode; } /* Ctrl-Z forked, we are parent; or Ctrl-C. * Sighandler has longjmped us here */ signal(SIGINT, SIG_IGN); signal(SIGTSTP, SIG_IGN); debug_jobs_printf("Exiting nofork early\n"); restore_nofork_data(&nofork_save); if (nofork_save.saved == 0) /* Ctrl-Z, not Ctrl-C */ insert_bg_job(pi); else putchar('\n'); /* bash does this on Ctrl-C */ return 0; #else return run_nofork_applet(a, argv); #endif } #endif /* run_pipe_real() starts all the jobs, but doesn'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_real returns, and the exit code is provided as the * return value. * * The input of the pipe is always stdin, the output is always * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus, * because it tries to avoid running the command substitution in * subshell, when that is in fact necessary. The subshell process * now has its stdout directed to the input of the appropriate pipe, * so this routine is noticeably simpler. */ static int run_pipe_real(struct pipe *pi) { int i; int nextin, nextout; int pipefds[2]; /* pipefds[0] is for reading */ struct child_prog *child; const struct built_in_command *x; char *p; /* it is not always needed, but we aim to smaller code */ int squirrel[] = { -1, -1, -1 }; int rcode; const int single_fg = (pi->num_progs == 1 && pi->followup != PIPE_BG); debug_exec_printf("run_pipe_real start:\n"); nextin = 0; #if ENABLE_HUSH_JOB pi->pgrp = -1; #endif pi->running_progs = 0; pi->stopped_progs = 0; /* Check if this is a simple builtin (not part of a pipe). * Builtins within pipes have to fork anyway, and are handled in * pseudo_exec. "echo foo | read bar" doesn't work on bash, either. */ child = &(pi->progs[0]); if (single_fg && child->group && child->subshell == 0) { debug_printf("non-subshell grouping\n"); setup_redirects(child, squirrel); /* XXX could we merge code with following builtin case, * by creating a pseudo builtin that calls run_list_real? */ debug_exec_printf(": run_list_real\n"); rcode = run_list_real(child->group); restore_redirects(squirrel); debug_exec_printf("run_pipe_real return %d\n", rcode); return rcode; } if (single_fg && child->argv != NULL) { char **argv = child->argv; for (i = 0; is_assignment(argv[i]); i++) continue; if (i != 0 && argv[i] == NULL) { /* assignments, but no command: set the local environment */ for (i = 0; argv[i] != NULL; i++) { /* Ok, this case is tricky. We have to decide if this is a * local variable, or an already exported variable. If it is * already exported, we have to export the new value. If it is * not exported, we need only set this as a local variable. * This junk is all to decide whether or not to export this * variable. */ int export_me = 0; char *name, *value; name = xstrdup(argv[i]); debug_printf("Local environment set: %s\n", name); value = strchr(name, '='); if (value) *value = 0; if (get_local_var(name)) { export_me = 1; } free(name); p = insert_var_value(argv[i]); set_local_var(p, export_me); if (p != argv[i]) free(p); } return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */ } for (i = 0; is_assignment(argv[i]); i++) { p = insert_var_value(argv[i]); putenv(strdup(p)); if (p != argv[i]) { child->sp--; free(p); } } if (child->sp) { char *str; str = make_string(argv + i); debug_exec_printf(": parse_string_outer '%s'\n", str); parse_string_outer(str, FLAG_EXIT_FROM_LOOP | FLAG_REPARSING); free(str); debug_exec_printf("run_pipe_real return %d\n", last_return_code); return last_return_code; } for (x = bltins; x->cmd; x++) { if (strcmp(argv[i], x->cmd) == 0) { if (x->function == builtin_exec && argv[i+1] == NULL) { debug_printf("magic exec\n"); setup_redirects(child, NULL); return EXIT_SUCCESS; } debug_printf("builtin inline %s\n", argv[0]); /* XXX 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 with glibc. */ // TODO: fflush(NULL)? setup_redirects(child, squirrel); debug_exec_printf(": builtin '%s' '%s'...\n", x->cmd, argv[i+1]); rcode = x->function(argv + i); restore_redirects(squirrel); debug_exec_printf("run_pipe_real return %d\n", rcode); return rcode; } } #if ENABLE_FEATURE_SH_STANDALONE { const struct bb_applet *a = find_applet_by_name(argv[i]); if (a && a->nofork) { setup_redirects(child, squirrel); debug_exec_printf(": run_single_fg_nofork '%s' '%s'...\n", argv[i], argv[i+1]); rcode = run_single_fg_nofork(pi, a, argv + i); restore_redirects(squirrel); debug_exec_printf("run_pipe_real return %d\n", rcode); return rcode; } } #endif } /* Going to fork a child per each pipe member */ /* Disable job control signals for shell (parent) and * for initial child code after fork */ set_jobctrl_sighandler(SIG_IGN); for (i = 0; i < pi->num_progs; i++) { child = &(pi->progs[i]); debug_exec_printf(": pipe member '%s' '%s'...\n", child->argv[0], child->argv[1]); /* pipes are inserted between pairs of commands */ if ((i + 1) < pi->num_progs) { if (pipe(pipefds) < 0) bb_perror_msg_and_die("pipe"); nextout = pipefds[1]; } else { nextout = 1; pipefds[0] = -1; } /* XXX test for failed fork()? */ #if BB_MMU child->pid = fork(); #else child->pid = vfork(); #endif if (!child->pid) { /* child */ /* Every child adds itself to new process group * with pgid == pid of first child in pipe */ #if ENABLE_HUSH_JOB if (interactive_fd) { /* Don't do pgrp restore anymore on fatal signals */ set_fatal_sighandler(SIG_DFL); if (pi->pgrp < 0) /* true for 1st process only */ pi->pgrp = getpid(); if (setpgid(0, pi->pgrp) == 0 && pi->followup != PIPE_BG) { /* We do it in *every* child, not just first, * to avoid races */ tcsetpgrp(interactive_fd, pi->pgrp); } } #endif // in non-interactive case fatal sigs are already SIG_DFL close_all(); if (nextin != 0) { dup2(nextin, 0); close(nextin); } if (nextout != 1) { dup2(nextout, 1); close(nextout); } if (pipefds[0] != -1) { close(pipefds[0]); /* opposite end of our output pipe */ } /* Like bash, explicit redirects override pipes, * and the pipe fd is available for dup'ing. */ setup_redirects(child, NULL); /* Restore default handlers just prior to exec */ set_jobctrl_sighandler(SIG_DFL); set_misc_sighandler(SIG_DFL); signal(SIGCHLD, SIG_DFL); pseudo_exec(child); } pi->running_progs++; #if ENABLE_HUSH_JOB /* Second and next children need to know pid of first one */ if (pi->pgrp < 0) pi->pgrp = child->pid; #endif /* Don't check for errors. The child may be dead already, * in which case setpgid returns error code EACCES. */ //why we do it at all?? child does it itself //if (interactive_fd) // setpgid(child->pid, pi->pgrp); if (nextin != 0) close(nextin); if (nextout != 1) close(nextout); /* If there isn't another process, nextin is garbage but it doesn't matter */ nextin = pipefds[0]; } debug_exec_printf("run_pipe_real return -1\n"); return -1; } static int run_list_real(struct pipe *pi) { char *save_name = NULL; char **list = NULL; char **save_list = NULL; struct pipe *rpipe; int flag_rep = 0; int save_num_progs; int rcode = 0, flag_skip = 1; int flag_restore = 0; int if_code = 0, next_if_code = 0; /* need double-buffer to handle elif */ reserved_style rmode, skip_more_in_this_rmode = RES_XXXX; debug_exec_printf("run_list_real start:\n"); /* check syntax for "for" */ for (rpipe = pi; rpipe; rpipe = rpipe->next) { if ((rpipe->r_mode == RES_IN || rpipe->r_mode == RES_FOR) && (rpipe->next == NULL) ) { syntax(); debug_exec_printf("run_list_real return 1\n"); return 1; } if ((rpipe->r_mode == RES_IN && rpipe->next->r_mode == RES_IN && rpipe->next->progs->argv != NULL) || (rpipe->r_mode == RES_FOR && rpipe->next->r_mode != RES_IN) ) { syntax(); debug_exec_printf("run_list_real return 1\n"); return 1; } } for (; pi; pi = (flag_restore != 0) ? rpipe : pi->next) { if (pi->r_mode == RES_WHILE || pi->r_mode == RES_UNTIL || pi->r_mode == RES_FOR ) { flag_restore = 0; if (!rpipe) { flag_rep = 0; rpipe = pi; } } rmode = pi->r_mode; debug_printf("rmode=%d if_code=%d next_if_code=%d skip_more=%d\n", rmode, if_code, next_if_code, skip_more_in_this_rmode); if (rmode == skip_more_in_this_rmode && flag_skip) { if (pi->followup == PIPE_SEQ) flag_skip = 0; continue; } flag_skip = 1; skip_more_in_this_rmode = RES_XXXX; if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code; if (rmode == RES_THEN && if_code) continue; if (rmode == RES_ELSE && !if_code) continue; if (rmode == RES_ELIF && !if_code) break; if (rmode == RES_FOR && pi->num_progs) { if (!list) { /* if no variable values after "in" we skip "for" */ if (!pi->next->progs->argv) continue; /* create list of variable values */ list = make_list_in(pi->next->progs->argv, pi->progs->argv[0]); save_list = list; save_name = pi->progs->argv[0]; pi->progs->argv[0] = NULL; flag_rep = 1; } if (!*list) { free(pi->progs->argv[0]); free(save_list); list = NULL; flag_rep = 0; pi->progs->argv[0] = save_name; pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0]; continue; } /* insert new value from list for variable */ if (pi->progs->argv[0]) free(pi->progs->argv[0]); pi->progs->argv[0] = *list++; pi->progs->glob_result.gl_pathv[0] = pi->progs->argv[0]; } if (rmode == RES_IN) continue; if (rmode == RES_DO) { if (!flag_rep) continue; } if (rmode == RES_DONE) { if (flag_rep) { flag_restore = 1; } else { rpipe = NULL; } } if (pi->num_progs == 0) continue; save_num_progs = pi->num_progs; /* save number of programs */ debug_exec_printf(": run_pipe_real with %d members\n", pi->num_progs); rcode = run_pipe_real(pi); if (rcode != -1) { /* We only ran a builtin: rcode was set by the return value * of run_pipe_real(), and we don't need to wait for anything. */ } else if (pi->followup == PIPE_BG) { /* XXX check bash's behavior with nontrivial pipes */ /* XXX compute jobid */ /* XXX what does bash do with attempts to background builtins? */ #if ENABLE_HUSH_JOB insert_bg_job(pi); #endif rcode = EXIT_SUCCESS; } else { #if ENABLE_HUSH_JOB if (interactive_fd) { rcode = checkjobs_and_fg_shell(pi); } else #endif { rcode = checkjobs(pi); } debug_printf("checkjobs returned %d\n", rcode); } last_return_code = rcode; pi->num_progs = save_num_progs; /* restore number of programs */ if (rmode == RES_IF || rmode == RES_ELIF) next_if_code = rcode; /* can be overwritten a number of times */ if (rmode == RES_WHILE) flag_rep = !last_return_code; if (rmode == RES_UNTIL) flag_rep = last_return_code; if ((rcode == EXIT_SUCCESS && pi->followup == PIPE_OR) || (rcode != EXIT_SUCCESS && pi->followup == PIPE_AND) ) { skip_more_in_this_rmode = rmode; } checkjobs(NULL); } debug_exec_printf("run_list_real return %d\n", rcode); return rcode; } /* return code is the exit status of the pipe */ static int free_pipe(struct pipe *pi, int indent) { char **p; struct child_prog *child; struct redir_struct *r, *rnext; int a, i, ret_code = 0; if (pi->stopped_progs > 0) return ret_code; final_printf("%s run pipe: (pid %d)\n", indenter(indent), getpid()); for (i = 0; i < pi->num_progs; i++) { child = &pi->progs[i]; final_printf("%s command %d:\n", indenter(indent), i); if (child->argv) { for (a = 0, p = child->argv; *p; a++, p++) { final_printf("%s argv[%d] = %s\n", indenter(indent), a, *p); } globfree(&child->glob_result); child->argv = NULL; } else if (child->group) { final_printf("%s begin group (subshell:%d)\n", indenter(indent), child->subshell); ret_code = free_pipe_list(child->group, indent+3); final_printf("%s end group\n", indenter(indent)); } else { final_printf("%s (nil)\n", indenter(indent)); } for (r = child->redirects; r; r = rnext) { final_printf("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->type].descrip); if (r->dup == -1) { /* guard against the case >$FOO, where foo is unset or blank */ if (r->word.gl_pathv) { final_printf(" %s\n", *r->word.gl_pathv); globfree(&r->word); } } else { final_printf("&%d\n", r->dup); } rnext = r->next; free(r); } child->redirects = NULL; } free(pi->progs); /* children are an array, they get freed all at once */ pi->progs = NULL; #if ENABLE_HUSH_JOB free(pi->cmdtext); pi->cmdtext = NULL; #endif return ret_code; } static int free_pipe_list(struct pipe *head, int indent) { int rcode = 0; /* if list has no members */ struct pipe *pi, *next; for (pi = head; pi; pi = next) { final_printf("%s pipe reserved mode %d\n", indenter(indent), pi->r_mode); rcode = free_pipe(pi, indent); final_printf("%s pipe followup code %d\n", indenter(indent), pi->followup); next = pi->next; /*pi->next = NULL;*/ free(pi); } return rcode; } /* Select which version we will use */ static int run_list(struct pipe *pi) { int rcode = 0; if (fake_mode == 0) { debug_exec_printf("run_list: run_list_real with %d members\n", pi->num_progs); rcode = run_list_real(pi); } /* free_pipe_list has the side effect of clearing memory * In the long run that function can be merged with run_list_real, * but doing that now would hobble the debugging effort. */ free_pipe_list(pi,0); return rcode; } /* The API for glob is arguably broken. This routine pushes a non-matching * string into the output structure, removing non-backslashed backslashes. * If someone can prove me wrong, by performing this function within the * original glob(3) api, feel free to rewrite this routine into oblivion. * Return code (0 vs. GLOB_NOSPACE) matches glob(3). * XXX broken if the last character is '\\', check that before calling. */ static int globhack(const char *src, int flags, glob_t *pglob) { int cnt = 0, pathc; const char *s; char *dest; for (cnt = 1, s = src; s && *s; s++) { if (*s == '\\') s++; cnt++; } dest = malloc(cnt); if (!dest) return GLOB_NOSPACE; if (!(flags & GLOB_APPEND)) { pglob->gl_pathv = NULL; pglob->gl_pathc = 0; pglob->gl_offs = 0; pglob->gl_offs = 0; } pathc = ++pglob->gl_pathc; pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv)); if (pglob->gl_pathv == NULL) return GLOB_NOSPACE; pglob->gl_pathv[pathc-1] = dest; pglob->gl_pathv[pathc] = NULL; for (s = src; s && *s; s++, dest++) { if (*s == '\\') s++; *dest = *s; } *dest = '\0'; return 0; } /* XXX broken if the last character is '\\', check that before calling */ static int glob_needed(const char *s) { for (; *s; s++) { if (*s == '\\') s++; if (strchr("*[?", *s)) return 1; } return 0; } static int xglob(o_string *dest, int flags, glob_t *pglob) { int gr; /* short-circuit for null word */ /* we can code this better when the debug_printf's are gone */ if (dest->length == 0) { if (dest->nonnull) { /* bash man page calls this an "explicit" null */ gr = globhack(dest->data, flags, pglob); debug_printf("globhack returned %d\n", gr); } else { return 0; } } else if (glob_needed(dest->data)) { gr = glob(dest->data, flags, NULL, pglob); debug_printf("glob returned %d\n", gr); if (gr == GLOB_NOMATCH) { /* quote removal, or more accurately, backslash removal */ gr = globhack(dest->data, flags, pglob); debug_printf("globhack returned %d\n", gr); } } else { gr = globhack(dest->data, flags, pglob); debug_printf("globhack returned %d\n", gr); } if (gr == GLOB_NOSPACE) bb_error_msg_and_die("out of memory during glob"); if (gr != 0) { /* GLOB_ABORTED ? */ bb_error_msg("glob(3) error %d", gr); } /* globprint(glob_target); */ return gr; } static char **make_list_in(char **inp, char *name) { int len, i; int name_len = strlen(name); int n = 0; char **list; char *p1, *p2, *p3; /* create list of variable values */ list = xmalloc(sizeof(*list)); for (i = 0; inp[i]; i++) { p3 = insert_var_value(inp[i]); p1 = p3; while (*p1) { if ((*p1 == ' ')) { p1++; continue; } p2 = strchr(p1, ' '); if (p2) { len = p2 - p1; } else { len = strlen(p1); p2 = p1 + len; } /* we use n + 2 in realloc for list, because we add * new element and then we will add NULL element */ list = xrealloc(list, sizeof(*list) * (n + 2)); list[n] = xmalloc(2 + name_len + len); strcpy(list[n], name); strcat(list[n], "="); strncat(list[n], p1, len); list[n++][name_len + len + 1] = '\0'; p1 = p2; } if (p3 != inp[i]) free(p3); } list[n] = NULL; return list; } static char *insert_var_value(char *inp) { int res_str_len = 0; int len; int done = 0; char *p, *res_str = NULL; const char *p1; while ((p = strchr(inp, SPECIAL_VAR_SYMBOL))) { if (p != inp) { len = p - inp; res_str = xrealloc(res_str, (res_str_len + len)); strncpy((res_str + res_str_len), inp, len); res_str_len += len; } inp = ++p; p = strchr(inp, SPECIAL_VAR_SYMBOL); *p = '\0'; p1 = lookup_param(inp); if (p1) { len = res_str_len + strlen(p1); res_str = xrealloc(res_str, (1 + len)); strcpy((res_str + res_str_len), p1); res_str_len = len; } *p = SPECIAL_VAR_SYMBOL; inp = ++p; done = 1; } if (done) { res_str = xrealloc(res_str, (1 + res_str_len + strlen(inp))); strcpy((res_str + res_str_len), inp); while ((p = strchr(res_str, '\n'))) { *p = ' '; } } return (res_str == NULL) ? inp : res_str; } /* This is used to get/check local shell variables */ static const char *get_local_var(const char *s) { struct variables *cur; if (!s) return NULL; for (cur = top_vars; cur; cur = cur->next) if (strcmp(cur->name, s) == 0) return cur->value; return NULL; } /* This is used to set local shell variables flg_export == 0 if only local (not exporting) variable flg_export == 1 if "new" exporting environ flg_export > 1 if current startup environ (not call putenv()) */ static int set_local_var(const char *s, int flg_export) { char *name, *value; int result = 0; struct variables *cur; name = strdup(s); /* Assume when we enter this function that we are already in * NAME=VALUE format. So the first order of business is to * split 's' on the '=' into 'name' and 'value' */ value = strchr(name, '='); /*if (value == 0 && ++value == 0) ??? -vda */ if (value == NULL || value[1] == '\0') { free(name); return -1; } *value++ = '\0'; for (cur = top_vars; cur; cur = cur->next) { if (strcmp(cur->name, name) == 0) break; } if (cur) { if (strcmp(cur->value, value) == 0) { if (flg_export > 0 && cur->flg_export == 0) cur->flg_export = flg_export; else result++; } else if (cur->flg_read_only) { bb_error_msg("%s: readonly variable", name); result = -1; } else { if (flg_export > 0 || cur->flg_export > 1) cur->flg_export = 1; free((char*)cur->value); cur->value = strdup(value); } } else { cur = malloc(sizeof(struct variables)); if (!cur) { result = -1; } else { cur->name = strdup(name); if (cur->name) { free(cur); result = -1; } else { struct variables *bottom = top_vars; cur->value = strdup(value); cur->next = 0; cur->flg_export = flg_export; cur->flg_read_only = 0; while (bottom->next) bottom = bottom->next; bottom->next = cur; } } } if (result == 0 && cur->flg_export == 1) { *(value-1) = '='; result = putenv(name); } else { free(name); if (result > 0) /* equivalent to previous set */ result = 0; } return result; } static void unset_local_var(const char *name) { struct variables *cur, *next; if (!name) return; for (cur = top_vars; cur; cur = cur->next) { if (strcmp(cur->name, name) == 0) { if (cur->flg_read_only) { bb_error_msg("%s: readonly variable", name); return; } if (cur->flg_export) unsetenv(cur->name); free((char*)cur->name); free((char*)cur->value); next = top_vars; while (next->next != cur) next = next->next; next->next = cur->next; free(cur); return; } } } static int is_assignment(const char *s) { if (!s || !isalpha(*s)) return 0; s++; while (isalnum(*s) || *s == '_') s++; return *s == '='; } /* the src parameter allows us to peek forward to a possible &n syntax * for file descriptor duplication, e.g., "2>&1". * Return code is 0 normally, 1 if a syntax error is detected in src. * Resource errors (in xmalloc) cause the process to exit */ static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input) { struct child_prog *child = ctx->child; struct redir_struct *redir = child->redirects; struct redir_struct *last_redir = NULL; /* Create a new redir_struct and drop it onto the end of the linked list */ while (redir) { last_redir = redir; redir = redir->next; } redir = xmalloc(sizeof(struct redir_struct)); redir->next = NULL; redir->word.gl_pathv = NULL; if (last_redir) { last_redir->next = redir; } else { child->redirects = redir; } redir->type = style; redir->fd = (fd == -1) ? redir_table[style].default_fd : fd; debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip); /* Check for a '2>&1' type redirect */ redir->dup = redirect_dup_num(input); if (redir->dup == -2) return 1; /* syntax error */ if (redir->dup != -1) { /* 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("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup); } else { /* We do _not_ try to open the file that src points to, * since we need to return and let src be expanded first. * Set ctx->pending_redirect, so we know what to do at the * end of the next parsed word. */ ctx->pending_redirect = redir; } return 0; } static struct pipe *new_pipe(void) { struct pipe *pi; pi = xzalloc(sizeof(struct pipe)); /*pi->num_progs = 0;*/ /*pi->progs = NULL;*/ /*pi->next = NULL;*/ /*pi->followup = 0; invalid */ if (RES_NONE) pi->r_mode = RES_NONE; return pi; } static void initialize_context(struct p_context *ctx) { ctx->pipe = NULL; ctx->pending_redirect = NULL; ctx->child = NULL; ctx->list_head = new_pipe(); ctx->pipe = ctx->list_head; ctx->w = RES_NONE; ctx->stack = NULL; ctx->old_flag = 0; done_command(ctx); /* creates the memory for working child */ } /* normal return is 0 * if a reserved word is found, and processed, return 1 * should handle if, then, elif, else, fi, for, while, until, do, done. * case, function, and select are obnoxious, save those for later. */ static int reserved_word(o_string *dest, struct p_context *ctx) { struct reserved_combo { char literal[7]; unsigned char code; int flag; }; /* 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", RES_IF, FLAG_THEN | FLAG_START }, { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI }, { "elif", RES_ELIF, FLAG_THEN }, { "else", RES_ELSE, FLAG_FI }, { "fi", RES_FI, FLAG_END }, { "for", RES_FOR, FLAG_IN | FLAG_START }, { "while", RES_WHILE, FLAG_DO | FLAG_START }, { "until", RES_UNTIL, FLAG_DO | FLAG_START }, { "in", RES_IN, FLAG_DO }, { "do", RES_DO, FLAG_DONE }, { "done", RES_DONE, FLAG_END } }; enum { NRES = sizeof(reserved_list)/sizeof(reserved_list[0]) }; const struct reserved_combo *r; for (r = reserved_list; r < reserved_list+NRES; r++) { if (strcmp(dest->data, r->literal) == 0) { debug_printf("found reserved word %s, code %d\n", r->literal, r->code); if (r->flag & FLAG_START) { struct p_context *new = xmalloc(sizeof(struct p_context)); debug_printf("push stack\n"); if (ctx->w == RES_IN || ctx->w == RES_FOR) { syntax(); free(new); ctx->w = RES_SNTX; b_reset(dest); return 1; } *new = *ctx; /* physical copy */ initialize_context(ctx); ctx->stack = new; } else if (ctx->w == RES_NONE || !(ctx->old_flag & (1 << r->code))) { syntax(); ctx->w = RES_SNTX; b_reset(dest); return 1; } ctx->w = r->code; ctx->old_flag = r->flag; if (ctx->old_flag & FLAG_END) { struct p_context *old; debug_printf("pop stack\n"); done_pipe(ctx, PIPE_SEQ); old = ctx->stack; old->child->group = ctx->list_head; old->child->subshell = 0; *ctx = *old; /* physical copy */ free(old); } b_reset(dest); return 1; } } return 0; } /* normal return is 0. * Syntax or xglob errors return 1. */ static int done_word(o_string *dest, struct p_context *ctx) { struct child_prog *child = ctx->child; glob_t *glob_target; int gr, flags = 0; debug_printf("done_word: %s %p\n", dest->data, child); if (dest->length == 0 && !dest->nonnull) { debug_printf(" true null, ignored\n"); return 0; } if (ctx->pending_redirect) { glob_target = &ctx->pending_redirect->word; } else { if (child->group) { syntax(); return 1; /* syntax error, groups and arglists don't mix */ } if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) { debug_printf("checking %s for reserved-ness\n", dest->data); if (reserved_word(dest, ctx)) return (ctx->w == RES_SNTX); } glob_target = &child->glob_result; if (child->argv) flags |= GLOB_APPEND; } gr = xglob(dest, flags, glob_target); if (gr != 0) return 1; b_reset(dest); if (ctx->pending_redirect) { ctx->pending_redirect = NULL; if (glob_target->gl_pathc != 1) { bb_error_msg("ambiguous redirect"); return 1; } } else { child->argv = glob_target->gl_pathv; } if (ctx->w == RES_FOR) { done_word(dest, ctx); done_pipe(ctx, PIPE_SEQ); } return 0; } /* The only possible error here is out of memory, in which case * xmalloc exits. */ static int done_command(struct p_context *ctx) { /* The child is really already in the pipe structure, so * advance the pipe counter and make a new, null child. * Only real trickiness here is that the uncommitted * child structure, to which ctx->child points, is not * counted in pi->num_progs. */ struct pipe *pi = ctx->pipe; struct child_prog *prog = ctx->child; if (prog && prog->group == NULL && prog->argv == NULL && prog->redirects == NULL ) { debug_printf("done_command: skipping null command\n"); return 0; } if (prog) { pi->num_progs++; debug_printf("done_command: num_progs incremented to %d\n", pi->num_progs); } else { debug_printf("done_command: initializing\n"); } pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1)); prog = pi->progs + pi->num_progs; memset(prog, 0, sizeof(*prog)); /*prog->redirects = NULL;*/ /*prog->argv = NULL; */ /*prog->is_stopped = 0;*/ /*prog->group = NULL;*/ /*prog->glob_result.gl_pathv = NULL;*/ prog->family = pi; /*prog->sp = 0;*/ ctx->child = prog; prog->type = ctx->type; /* but ctx->pipe and ctx->list_head remain unchanged */ return 0; } static int done_pipe(struct p_context *ctx, pipe_style type) { struct pipe *new_p; done_command(ctx); /* implicit closure of previous command */ debug_printf("done_pipe, type %d\n", type); ctx->pipe->followup = type; ctx->pipe->r_mode = ctx->w; new_p = new_pipe(); ctx->pipe->next = new_p; ctx->pipe = new_p; ctx->child = NULL; done_command(ctx); /* set up new pipe to accept commands */ return 0; } /* peek ahead in the in_str to find out if we have a "&n" construct, * as in "2>&1", that represents duplicating a file descriptor. * returns either -2 (syntax error), -1 (no &), or the number found. */ static int redirect_dup_num(struct in_str *input) { int ch, d = 0, ok = 0; ch = b_peek(input); if (ch != '&') return -1; b_getch(input); /* get the & */ ch = b_peek(input); if (ch == '-') { b_getch(input); return -3; /* "-" represents "close me" */ } while (isdigit(ch)) { d = d*10 + (ch-'0'); ok = 1; b_getch(input); ch = b_peek(input); } if (ok) return d; bb_error_msg("ambiguous redirect"); return -2; } /* 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 * A -1 output from this program means no valid number was found, so the * caller should use the appropriate default for this redirection. */ static int redirect_opt_num(o_string *o) { int num; if (o->length == 0) return -1; for (num = 0; num < o->length; num++) { if (!isdigit(*(o->data + num))) { return -1; } } /* reuse num (and save an int) */ num = atoi(o->data); b_reset(o); return num; } static FILE *generate_stream_from_list(struct pipe *head) { FILE *pf; int pid, channel[2]; if (pipe(channel) < 0) bb_perror_msg_and_die("pipe"); #if BB_MMU pid = fork(); #else pid = vfork(); #endif if (pid < 0) { bb_perror_msg_and_die("fork"); } else if (pid == 0) { close(channel[0]); if (channel[1] != 1) { dup2(channel[1], 1); close(channel[1]); } _exit(run_list_real(head)); /* leaks memory */ } debug_printf("forked child %d\n", pid); close(channel[1]); pf = fdopen(channel[0], "r"); debug_printf("pipe on FILE *%p\n", pf); return pf; } /* this version hacked for testing purposes */ /* return code is exit status of the process that is run. */ static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end) { int retcode; o_string result = NULL_O_STRING; struct p_context inner; FILE *p; struct in_str pipe_str; initialize_context(&inner); /* recursion to generate command */ retcode = parse_stream(&result, &inner, input, subst_end); if (retcode != 0) return retcode; /* syntax error or EOF */ done_word(&result, &inner); done_pipe(&inner, PIPE_SEQ); b_free(&result); p = generate_stream_from_list(inner.list_head); if (p == NULL) return 1; mark_open(fileno(p)); setup_file_in_str(&pipe_str, p); /* now send results of command back into original context */ retcode = parse_stream(dest, ctx, &pipe_str, '\0'); /* XXX In case of a syntax error, should we try to kill the child? * That would be tough to do right, so just read until EOF. */ if (retcode == 1) { while (b_getch(&pipe_str) != EOF) /* discard */; } debug_printf("done reading from pipe, pclose()ing\n"); /* This is the step that wait()s for the child. Should be pretty * safe, since we just read an EOF from its stdout. We could try * to better, by using wait(), and keeping track of background jobs * at the same time. That would be a lot of work, and contrary * to the KISS philosophy of this program. */ mark_closed(fileno(p)); retcode = pclose(p); free_pipe_list(inner.list_head, 0); debug_printf("pclosed, retcode=%d\n", retcode); /* XXX this process fails to trim a single trailing newline */ return retcode; } static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch) { int rcode, endch = 0; struct p_context sub; struct child_prog *child = ctx->child; if (child->argv) { syntax(); return 1; /* syntax error, groups and arglists don't mix */ } initialize_context(&sub); switch (ch) { case '(': endch = ')'; child->subshell = 1; break; case '{': endch = '}'; break; default: syntax(); /* really logic error */ } rcode = parse_stream(dest, &sub, input, endch); done_word(dest, &sub); /* finish off the final word in the subcontext */ done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */ child->group = sub.list_head; return rcode; /* child remains "open", available for possible redirects */ } /* basically useful version until someone wants to get fancier, * see the bash man page under "Parameter Expansion" */ static const char *lookup_param(const char *src) { const char *p = NULL; if (src) { p = getenv(src); if (!p) p = get_local_var(src); } return p; } /* Make new string for parser */ static char* make_string(char ** inp) { char *p; char *str = NULL; int n; int len = 2; for (n = 0; inp[n]; n++) { p = insert_var_value(inp[n]); str = xrealloc(str, (len + strlen(p))); if (n) { strcat(str, " "); } else { *str = '\0'; } strcat(str, p); len = strlen(str) + 3; if (p != inp[n]) free(p); } len = strlen(str); str[len] = '\n'; str[len+1] = '\0'; return str; } /* return code: 0 for OK, 1 for syntax error */ static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input) { int i, advance = 0; char sep[] = " "; int ch = input->peek(input); /* first character after the $ */ debug_printf("handle_dollar: ch=%c\n", ch); if (isalpha(ch)) { b_addchr(dest, SPECIAL_VAR_SYMBOL); ctx->child->sp++; while (ch = b_peek(input), isalnum(ch) || ch == '_') { b_getch(input); b_addchr(dest, ch); } b_addchr(dest, SPECIAL_VAR_SYMBOL); } else if (isdigit(ch)) { i = ch - '0'; /* XXX is $0 special? */ if (i < global_argc) { parse_string(dest, ctx, global_argv[i]); /* recursion */ } advance = 1; } else switch (ch) { case '$': b_adduint(dest, getpid()); advance = 1; break; case '!': if (last_bg_pid > 0) b_adduint(dest, last_bg_pid); advance = 1; break; case '?': b_adduint(dest, last_return_code); advance = 1; break; case '#': b_adduint(dest, global_argc ? global_argc-1 : 0); advance = 1; break; case '{': b_addchr(dest, SPECIAL_VAR_SYMBOL); ctx->child->sp++; b_getch(input); /* XXX maybe someone will try to escape the '}' */ while (1) { ch = b_getch(input); if (ch == EOF || ch == '}') break; b_addchr(dest, ch); } if (ch != '}') { syntax(); return 1; } b_addchr(dest, SPECIAL_VAR_SYMBOL); break; case '(': b_getch(input); process_command_subs(dest, ctx, input, ')'); break; case '*': sep[0] = ifs[0]; for (i = 1; i < global_argc; i++) { parse_string(dest, ctx, global_argv[i]); if (i+1 < global_argc) parse_string(dest, ctx, sep); } break; case '@': case '-': case '_': /* still unhandled, but should be eventually */ bb_error_msg("unhandled syntax: $%c", ch); return 1; break; default: b_addqchr(dest,'$', dest->quote); } /* Eat the character if the flag was set. If the compiler * is smart enough, we could substitute "b_getch(input);" * for all the "advance = 1;" above, and also end up with * a nice size-optimized program. Hah! That'll be the day. */ if (advance) b_getch(input); return 0; } static int parse_string(o_string *dest, struct p_context *ctx, const char *src) { struct in_str foo; setup_string_in_str(&foo, src); return parse_stream(dest, ctx, &foo, '\0'); } /* return code is 0 for normal exit, 1 for syntax error */ static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input, int end_trigger) { int ch, m; int redir_fd; redir_type redir_style; int next; /* Only double-quote state is handled in the state variable dest->quote. * A single-quote triggers a bypass of the main loop until its mate is * found. When recursing, quote state is passed in via dest->quote. */ debug_printf("parse_stream, end_trigger=%d\n", end_trigger); while ((ch = b_getch(input)) != EOF) { m = map[ch]; next = (ch == '\n') ? 0 : b_peek(input); debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n", ch, ch, m, dest->quote); if (m == 0 || ((m == 1 || m == 2) && dest->quote)) { b_addqchr(dest, ch, dest->quote); continue; } if (m == 2) { /* unquoted IFS */ if (done_word(dest, ctx)) { return 1; } /* If we aren't performing a substitution, treat a newline as a * command separator. */ if (end_trigger != '\0' && ch == '\n') done_pipe(ctx, PIPE_SEQ); } if (ch == end_trigger && !dest->quote && ctx->w == RES_NONE) { debug_printf("leaving parse_stream (triggered)\n"); return 0; } if (m == 2) continue; switch (ch) { case '#': if (dest->length == 0 && !dest->quote) { while (1) { ch = b_peek(input); if (ch == EOF || ch == '\n') break; b_getch(input); } } else { b_addqchr(dest, ch, dest->quote); } break; case '\\': if (next == EOF) { syntax(); return 1; } b_addqchr(dest, '\\', dest->quote); b_addqchr(dest, b_getch(input), dest->quote); break; case '$': if (handle_dollar(dest, ctx, input) != 0) return 1; break; case '\'': dest->nonnull = 1; while (1) { ch = b_getch(input); if (ch == EOF || ch == '\'') break; b_addchr(dest, ch); } if (ch == EOF) { syntax(); return 1; } break; case '"': dest->nonnull = 1; dest->quote = !dest->quote; break; case '`': process_command_subs(dest, ctx, input, '`'); break; case '>': redir_fd = redirect_opt_num(dest); done_word(dest, ctx); redir_style = REDIRECT_OVERWRITE; if (next == '>') { redir_style = REDIRECT_APPEND; b_getch(input); } else if (next == '(') { syntax(); /* until we support >(list) Process Substitution */ return 1; } setup_redirect(ctx, redir_fd, redir_style, input); break; case '<': redir_fd = redirect_opt_num(dest); done_word(dest, ctx); redir_style = REDIRECT_INPUT; if (next == '<') { redir_style = REDIRECT_HEREIS; b_getch(input); } else if (next == '>') { redir_style = REDIRECT_IO; b_getch(input); } else if (next == '(') { syntax(); /* until we support <(list) Process Substitution */ return 1; } setup_redirect(ctx, redir_fd, redir_style, input); break; case ';': done_word(dest, ctx); done_pipe(ctx, PIPE_SEQ); break; case '&': done_word(dest, ctx); if (next == '&') { b_getch(input); done_pipe(ctx, PIPE_AND); } else { done_pipe(ctx, PIPE_BG); } break; case '|': done_word(dest, ctx); if (next == '|') { b_getch(input); 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); } break; case '(': case '{': if (parse_group(dest, ctx, input, ch) != 0) return 1; break; case ')': case '}': syntax(); /* Proper use of this character caught by end_trigger */ return 1; default: syntax(); /* this is really an internal logic error */ return 1; } } /* complain if quote? No, maybe we just finished a command substitution * that was quoted. Example: * $ echo "`cat foo` plus more" * and we just got the EOF generated by the subshell that ran "cat foo" * The only real complaint is if we got an EOF when end_trigger != '\0', * that is, we were really supposed to get end_trigger, and never got * one before the EOF. Can't use the standard "syntax error" return code, * so that parse_stream_outer can distinguish the EOF and exit smoothly. */ debug_printf("leaving parse_stream (EOF)\n"); if (end_trigger != '\0') return -1; return 0; } static void mapset(const char *set, int code) { while (*set) map[(unsigned char)*set++] = code; } static void update_ifs_map(void) { /* char *ifs and char map[256] are both globals. */ ifs = getenv("IFS"); if (ifs == NULL) ifs = " \t\n"; /* Precompute a list of 'flow through' behavior so it can be treated * quickly up front. Computation is necessary because of IFS. * Special case handling of IFS == " \t\n" is not implemented. * The map[] array only really needs two bits each, and on most machines * that would be faster because of the reduced L1 cache footprint. */ memset(map, 0, sizeof(map)); /* most characters flow through always */ mapset("\\$'\"`", 3); /* never flow through */ mapset("<>;&|(){}#", 1); /* flow through if quoted */ mapset(ifs, 2); /* also flow through if quoted */ } /* most recursion does not come through here, the exception is * from builtin_source() */ static int parse_stream_outer(struct in_str *inp, int flag) { // FIXME: 'true | exit 3; echo $?' is parsed as a whole, // as a result $? is replaced by 0, not 3! // Need to stop & execute stuff at ';', not parse till EOL! struct p_context ctx; o_string temp = NULL_O_STRING; int rcode; do { ctx.type = flag; initialize_context(&ctx); update_ifs_map(); if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING)) mapset(";$&|", 0); #if ENABLE_HUSH_INTERACTIVE inp->promptmode = 1; #endif rcode = parse_stream(&temp, &ctx, inp, '\n'); if (rcode != 1 && ctx.old_flag != 0) { syntax(); } if (rcode != 1 && ctx.old_flag == 0) { done_word(&temp, &ctx); done_pipe(&ctx, PIPE_SEQ); debug_exec_printf("parse_stream_outer: run_list\n"); run_list(ctx.list_head); } else { if (ctx.old_flag != 0) { free(ctx.stack); b_reset(&temp); } temp.nonnull = 0; temp.quote = 0; inp->p = NULL; free_pipe_list(ctx.list_head, 0); } b_free(&temp); } while (rcode != -1 && !(flag & FLAG_EXIT_FROM_LOOP)); /* loop on syntax errors, return on EOF */ return 0; } static int parse_string_outer(const char *s, int flag) { struct in_str input; setup_string_in_str(&input, s); return parse_stream_outer(&input, flag); } static int parse_file_outer(FILE *f) { int rcode; struct in_str input; setup_file_in_str(&input, f); rcode = parse_stream_outer(&input, FLAG_PARSE_SEMICOLON); return rcode; } #if ENABLE_HUSH_JOB /* Make sure we have a controlling tty. If we get started under a job * aware app (like bash for example), make sure we are now in charge so * we don't fight over who gets the foreground */ static void setup_job_control(void) { pid_t shell_pgrp; saved_task_pgrp = shell_pgrp = getpgrp(); debug_printf("saved_task_pgrp=%d\n", saved_task_pgrp); fcntl(interactive_fd, F_SETFD, FD_CLOEXEC); /* If we were ran as 'hush &', * sleep until we are in the foreground. */ while (tcgetpgrp(interactive_fd) != shell_pgrp) { /* Send TTIN to ourself (should stop us) */ kill(- shell_pgrp, SIGTTIN); shell_pgrp = getpgrp(); } /* Ignore job-control and misc signals. */ set_jobctrl_sighandler(SIG_IGN); set_misc_sighandler(SIG_IGN); //huh? signal(SIGCHLD, SIG_IGN); /* We _must_ restore tty pgrp fatal signals */ set_fatal_sighandler(sigexit); /* Put ourselves in our own process group. */ setpgrp(); /* is the same as setpgid(our_pid, our_pid); */ /* Grab control of the terminal. */ tcsetpgrp(interactive_fd, getpid()); } #endif int hush_main(int argc, char **argv); int hush_main(int argc, char **argv) { int opt; FILE *input; char **e; #if ENABLE_FEATURE_EDITING line_input_state = new_line_input_t(FOR_SHELL); #endif /* XXX what should these be while sourcing /etc/profile? */ global_argc = argc; global_argv = argv; /* (re?) initialize globals. Sometimes hush_main() ends up calling * hush_main(), therefore we cannot rely on the BSS to zero out this * stuff. Reset these to 0 every time. */ ifs = NULL; /* map[] is taken care of with call to update_ifs_map() */ fake_mode = 0; close_me_head = NULL; #if ENABLE_HUSH_INTERACTIVE interactive_fd = 0; #endif #if ENABLE_HUSH_JOB last_bg_pid = 0; job_list = NULL; last_jobid = 0; #endif /* Initialize some more globals to non-zero values */ set_cwd(); #if ENABLE_HUSH_INTERACTIVE #if ENABLE_FEATURE_EDITING cmdedit_set_initial_prompt(); #else PS1 = NULL; #endif PS2 = "> "; #endif /* initialize our shell local variables with the values * currently living in the environment */ e = environ; if (e) while (*e) set_local_var(*e++, 2); /* without call putenv() */ last_return_code = EXIT_SUCCESS; if (argv[0] && argv[0][0] == '-') { debug_printf("\nsourcing /etc/profile\n"); input = fopen("/etc/profile", "r"); if (input != NULL) { mark_open(fileno(input)); parse_file_outer(input); mark_closed(fileno(input)); fclose(input); } } input = stdin; while ((opt = getopt(argc, argv, "c:xif")) > 0) { switch (opt) { case 'c': global_argv = argv + optind; global_argc = argc - optind; opt = parse_string_outer(optarg, FLAG_PARSE_SEMICOLON); goto final_return; case 'i': // Well, we cannot just declare interactiveness, // we have to have some stuff (ctty, etc) /*interactive_fd++;*/ break; case 'f': fake_mode++; 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 } } #if ENABLE_HUSH_JOB /* 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 (argv[optind] == NULL && input == stdin && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO) ) { saved_tty_pgrp = tcgetpgrp(STDIN_FILENO); debug_printf("saved_tty_pgrp=%d\n", saved_tty_pgrp); if (saved_tty_pgrp >= 0) { /* try to dup to high fd#, >= 255 */ interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255); if (interactive_fd < 0) { /* try to dup to any fd */ interactive_fd = dup(STDIN_FILENO); if (interactive_fd < 0) /* give up */ interactive_fd = 0; } // TODO: track & disallow any attempts of user // to (inadvertently) close/redirect it } } debug_printf("\ninteractive_fd=%d\n", interactive_fd); if (interactive_fd) { /* Looks like they want an interactive shell */ setup_job_control(); /* Make xfuncs do cleanup on exit */ die_sleep = -1; /* flag */ if (setjmp(die_jmp)) { /* xfunc has failed! die die die */ hush_exit(xfunc_error_retval); } #if !ENABLE_FEATURE_SH_EXTRA_QUIET printf("\n\n%s hush - the humble shell v"HUSH_VER_STR"\n", BB_BANNER); printf("Enter 'help' for a list of built-in commands.\n\n"); #endif } #elif ENABLE_HUSH_INTERACTIVE /* no job control compiled, only prompt/line editing */ if (argv[optind] == NULL && input == stdin && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO) ) { interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255); if (interactive_fd < 0) { /* try to dup to any fd */ interactive_fd = dup(STDIN_FILENO); if (interactive_fd < 0) /* give up */ interactive_fd = 0; } } #endif if (argv[optind] == NULL) { opt = parse_file_outer(stdin); goto final_return; } debug_printf("\nrunning script '%s'\n", argv[optind]); global_argv = argv + optind; global_argc = argc - optind; input = xfopen(argv[optind], "r"); opt = parse_file_outer(input); #if ENABLE_FEATURE_CLEAN_UP fclose(input); if (cwd != bb_msg_unknown) free((char*)cwd); { struct variables *cur, *tmp; for (cur = top_vars; cur; cur = tmp) { tmp = cur->next; if (!cur->flg_read_only) { free((char*)cur->name); free((char*)cur->value); free(cur); } } } #endif final_return: hush_exit(opt ? opt : last_return_code); }