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https://github.com/sheumann/hush.git
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hush: make job control and interactiveness configurable, part 1
This commit is contained in:
Denis Vlasenko
parent
0937be5fa6
commit
b81b3df1fa
@ -176,6 +176,15 @@ config HUSH
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word ), arithmetic expansion, aliases, brace expansion, tilde
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expansion, &> and >& redirection of stdout+stderr, etc.
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config HUSH_INTERACTIVE
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bool "Interactive mode"
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default y
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depends on HUSH
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help
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Enable interactive mode (Ctrl-Z, Ctrl-C, command editing)
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in the hush shell. Without this, hush reads and executes
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stdin just like a shell script from the file.
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config LASH
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bool "lash"
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116
shell/hush.c
116
shell/hush.c
@ -51,7 +51,7 @@
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* Here Documents ( << word )
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* Functions
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* Major bugs:
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* job handling woefully incomplete and buggy
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* job handling woefully incomplete and buggy (improved --vda)
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* reserved word execution woefully incomplete and buggy
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* to-do:
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* port selected bugfixes from post-0.49 busybox lash - done?
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@ -86,6 +86,16 @@
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/* Finer-grained debug switch */
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//#define DEBUG_SHELL_JOBS
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//TODO: rename HUSH_INTERACTIVE -> HUSH_JOB,
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//create HUSH_INTERACTIVE which controls only prompt + line editing,
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//make HUSH_JOB dependent on it
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#if !ENABLE_HUSH_INTERACTIVE
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#undef ENABLE_FEATURE_EDITING
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#define ENABLE_FEATURE_EDITING 0
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#undef ENABLE_FEATURE_EDITING_FANCY_PROMPT
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#define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0
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#endif
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#define SPECIAL_VAR_SYMBOL 03
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#define FLAG_EXIT_FROM_LOOP 1
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@ -169,10 +179,10 @@ struct p_context {
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};
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struct redir_struct {
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struct redir_struct *next; /* pointer to the next redirect in the list */
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redir_type type; /* type of redirection */
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int fd; /* file descriptor being redirected */
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int dup; /* -1, or file descriptor being duplicated */
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struct redir_struct *next; /* pointer to the next redirect in the list */
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glob_t word; /* *word.gl_pathv is the filename */
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};
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@ -190,14 +200,16 @@ struct child_prog {
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};
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struct pipe {
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int jobid; /* job number */
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struct pipe *next;
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int num_progs; /* total number of programs in job */
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int running_progs; /* number of programs running (not exited) */
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char *cmdtext; /* name of job */
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char *cmdbuf; /* buffer various argv's point into */
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#if ENABLE_HUSH_INTERACTIVE
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int jobid; /* job number */
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char *cmdtext; /* name of job */
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pid_t pgrp; /* process group ID for the job */
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#endif
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struct child_prog *progs; /* array of commands in pipe */
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struct pipe *next; /* to track background commands */
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int stopped_progs; /* number of programs alive, but stopped */
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int job_context; /* bitmask defining current context */
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pipe_style followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
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@ -205,16 +217,16 @@ struct pipe {
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};
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struct close_me {
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int fd;
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struct close_me *next;
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int fd;
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};
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struct variables {
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struct variables *next;
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const char *name;
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const char *value;
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int flg_export;
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int flg_read_only;
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struct variables *next;
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};
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/* globals, connect us to the outside world
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@ -230,18 +242,22 @@ static unsigned char map[256];
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static int fake_mode;
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static struct close_me *close_me_head;
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static const char *cwd;
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static struct pipe *job_list;
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static unsigned last_bg_pid;
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#if ENABLE_HUSH_INTERACTIVE
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static int last_jobid;
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static struct pipe *job_list;
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/* 'interactive_fd' is a fd# open to ctty, if we have one
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* _AND_ if we decided to mess with job control */
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static int interactive_fd;
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static pid_t saved_task_pgrp;
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static pid_t saved_tty_pgrp;
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#else
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enum { interactive_fd = 0 };
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#endif
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static const char *PS1;
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static const char *PS2;
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static struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
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static struct variables shell_ver = { NULL, "HUSH_VERSION", "0.01", 1, 1 };
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static struct variables *top_vars = &shell_ver;
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@ -322,9 +338,11 @@ static int builtin_eval(char **argv);
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static int builtin_exec(char **argv);
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static int builtin_exit(char **argv);
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static int builtin_export(char **argv);
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#if ENABLE_HUSH_INTERACTIVE
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static int builtin_fg_bg(char **argv);
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static int builtin_help(char **argv);
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static int builtin_jobs(char **argv);
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#endif
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static int builtin_help(char **argv);
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static int builtin_pwd(char **argv);
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static int builtin_read(char **argv);
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static int builtin_set(char **argv);
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@ -387,10 +405,14 @@ static int parse_string_outer(const char *s, int flag);
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static int parse_file_outer(FILE *f);
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/* job management: */
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static int checkjobs(struct pipe* fg_pipe);
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#if ENABLE_HUSH_INTERACTIVE
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static int checkjobs_and_fg_shell(struct pipe* fg_pipe);
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static void insert_bg_job(struct pipe *pi);
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static void remove_bg_job(struct pipe *pi);
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static void delete_finished_bg_job(struct pipe *pi);
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#else
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int checkjobs_and_fg_shell(struct pipe* fg_pipe); /* never called */
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#endif
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/* local variable support */
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static char **make_list_in(char **inp, char *name);
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static char *insert_var_value(char *inp);
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@ -405,7 +427,9 @@ static void unset_local_var(const char *name);
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* For example, 'unset foo | whatever' will parse and run, but foo will
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* still be set at the end. */
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static const struct built_in_command bltins[] = {
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#if ENABLE_HUSH_INTERACTIVE
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{ "bg", "Resume a job in the background", builtin_fg_bg },
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#endif
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{ "break", "Exit for, while or until loop", builtin_not_written },
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{ "cd", "Change working directory", builtin_cd },
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{ "continue", "Continue for, while or until loop", builtin_not_written },
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@ -415,8 +439,10 @@ static const struct built_in_command bltins[] = {
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builtin_exec },
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{ "exit", "Exit from shell()", builtin_exit },
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{ "export", "Set environment variable", builtin_export },
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#if ENABLE_HUSH_INTERACTIVE
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{ "fg", "Bring job into the foreground", builtin_fg_bg },
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{ "jobs", "Lists the active jobs", builtin_jobs },
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#endif
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{ "pwd", "Print current directory", builtin_pwd },
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{ "read", "Input environment variable", builtin_read },
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{ "return", "Return from a function", builtin_not_written },
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@ -431,6 +457,9 @@ static const struct built_in_command bltins[] = {
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{ NULL, NULL, NULL }
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};
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#if ENABLE_HUSH_INTERACTIVE
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#if ENABLE_FEATURE_SH_STANDALONE
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/* move to libbb? */
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static void signal_SA_RESTART(int sig, void (*handler)(int))
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{
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@ -440,6 +469,7 @@ static void signal_SA_RESTART(int sig, void (*handler)(int))
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sigemptyset(&sa.sa_mask);
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sigaction(sig, &sa, NULL);
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}
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#endif
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/* Signals are grouped, we handle them in batches */
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static void set_fatal_sighandler(void (*handler)(int))
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@ -469,6 +499,7 @@ static void set_misc_sighandler(void (*handler)(int))
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}
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/* SIGCHLD is special and handled separately */
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#if ENABLE_FEATURE_SH_STANDALONE
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static void set_every_sighandler(void (*handler)(int))
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{
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set_fatal_sighandler(handler);
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@ -477,9 +508,9 @@ static void set_every_sighandler(void (*handler)(int))
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signal(SIGCHLD, handler);
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}
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static struct pipe *nofork_pipe;
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struct nofork_save_area nofork_save;
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static sigjmp_buf nofork_jb;
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static struct pipe *nofork_pipe;
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static void handler_ctrl_c(int sig)
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{
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@ -522,6 +553,8 @@ static void handler_ctrl_z(int sig)
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siglongjmp(nofork_jb, 1);
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}
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#endif
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/* Restores tty foreground process group, and exits.
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* May be called as signal handler for fatal signal
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* (will faithfully resend signal to itself, producing correct exit state)
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@ -559,6 +592,16 @@ static void hush_exit(int exitcode)
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sigexit(- (exitcode & 0xff));
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}
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#else /* !INTERACTIVE */
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#define set_fatal_sighandler(handler) ((void)0)
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#define set_jobctrl_sighandler(handler) ((void)0)
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#define set_misc_sighandler(handler) ((void)0)
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#define hush_exit(e) exit(-(e))
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#endif /* INTERACTIVE */
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static const char *set_cwd(void)
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{
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if (cwd == bb_msg_unknown)
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@ -684,6 +727,7 @@ static int builtin_export(char **argv)
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return res;
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}
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#if ENABLE_HUSH_INTERACTIVE
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/* built-in 'fg' and 'bg' handler */
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static int builtin_fg_bg(char **argv)
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{
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@ -745,6 +789,7 @@ static int builtin_fg_bg(char **argv)
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}
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return EXIT_SUCCESS;
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}
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#endif
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/* built-in 'help' handler */
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static int builtin_help(char **argv ATTRIBUTE_UNUSED)
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@ -762,6 +807,7 @@ static int builtin_help(char **argv ATTRIBUTE_UNUSED)
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return EXIT_SUCCESS;
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}
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#if ENABLE_HUSH_INTERACTIVE
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/* built-in 'jobs' handler */
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static int builtin_jobs(char **argv ATTRIBUTE_UNUSED)
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{
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@ -778,6 +824,7 @@ static int builtin_jobs(char **argv ATTRIBUTE_UNUSED)
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}
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return EXIT_SUCCESS;
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}
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#endif
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/* built-in 'pwd' handler */
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static int builtin_pwd(char **argv ATTRIBUTE_UNUSED)
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@ -1272,7 +1319,9 @@ static void pseudo_exec(struct child_prog *child)
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if (child->group) {
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debug_printf("runtime nesting to group\n");
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// FIXME: do not modify globals! Think vfork!
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#if ENABLE_HUSH_INTERACTIVE
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interactive_fd = 0; /* crucial!!!! */
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#endif
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rcode = run_list_real(child->group);
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/* OK to leak memory by not calling free_pipe_list,
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* since this process is about to exit */
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@ -1284,6 +1333,7 @@ static void pseudo_exec(struct child_prog *child)
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_exit(EXIT_SUCCESS);
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}
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#if ENABLE_HUSH_INTERACTIVE
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static const char *get_cmdtext(struct pipe *pi)
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{
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char **argv;
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@ -1312,7 +1362,9 @@ static const char *get_cmdtext(struct pipe *pi)
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p[-1] = '\0';
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return pi->cmdtext;
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}
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#endif
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#if ENABLE_HUSH_INTERACTIVE
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static void insert_bg_job(struct pipe *pi)
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{
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struct pipe *thejob;
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@ -1376,6 +1428,7 @@ static void delete_finished_bg_job(struct pipe *pi)
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free_pipe(pi, 0);
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free(pi);
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}
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#endif
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/* Checks to see if any processes have exited -- if they
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have, figure out why and see if a job has completed */
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@ -1383,8 +1436,10 @@ static int checkjobs(struct pipe* fg_pipe)
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{
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int attributes;
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int status;
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#if ENABLE_HUSH_INTERACTIVE
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int prognum = 0;
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struct pipe *pi;
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#endif
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pid_t childpid;
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int rcode = 0;
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@ -1401,6 +1456,10 @@ static int checkjobs(struct pipe* fg_pipe)
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* 1 <========== bg pipe is not fully done, but exitcode is already known!
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*/
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//FIXME: non-interactive bash does not continue even if all processes in fg pipe
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//are stopped. Testcase: "cat | cat" in a script (not on command line)
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// + killall -STOP cat
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wait_more:
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while ((childpid = waitpid(-1, &status, attributes)) > 0) {
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const int dead = WIFEXITED(status) || WIFSIGNALED(status);
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@ -1437,8 +1496,10 @@ static int checkjobs(struct pipe* fg_pipe)
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fg_pipe->running_progs, fg_pipe->stopped_progs);
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if (fg_pipe->running_progs - fg_pipe->stopped_progs <= 0) {
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/* All processes in fg pipe have exited/stopped */
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#if ENABLE_HUSH_INTERACTIVE
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if (fg_pipe->running_progs)
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insert_bg_job(fg_pipe);
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#endif
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return rcode;
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}
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/* There are still running processes in the fg pipe */
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@ -1448,6 +1509,7 @@ static int checkjobs(struct pipe* fg_pipe)
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/* fall through to searching process in bg pipes */
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}
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#if ENABLE_HUSH_INTERACTIVE
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/* We asked to wait for bg or orphaned children */
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/* No need to remember exitcode in this case */
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for (pi = job_list; pi; pi = pi->next) {
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@ -1458,11 +1520,13 @@ static int checkjobs(struct pipe* fg_pipe)
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prognum++;
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}
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}
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#endif
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/* Happens when shell is used as init process (init=/bin/sh) */
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debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
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goto wait_more;
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#if ENABLE_HUSH_INTERACTIVE
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found_pi_and_prognum:
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if (dead) {
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/* child exited */
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@ -1478,6 +1542,7 @@ static int checkjobs(struct pipe* fg_pipe)
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pi->stopped_progs++;
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pi->progs[prognum].is_stopped = 1;
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}
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#endif
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}
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/* wait found no children or failed */
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@ -1491,6 +1556,7 @@ static int checkjobs(struct pipe* fg_pipe)
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return rcode;
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}
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#if ENABLE_HUSH_INTERACTIVE
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static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
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{
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pid_t p;
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@ -1502,11 +1568,14 @@ static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
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bb_perror_msg("tcsetpgrp-4a");
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return rcode;
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}
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#endif
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#if ENABLE_FEATURE_SH_STANDALONE
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/* run_pipe_real's helper */
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static int run_single_fg_nofork(struct pipe *pi, const struct bb_applet *a,
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char **argv)
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{
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#if ENABLE_HUSH_INTERACTIVE
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int rcode;
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/* TSTP handler will store pid etc in pi */
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nofork_pipe = pi;
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@ -1532,7 +1601,11 @@ static int run_single_fg_nofork(struct pipe *pi, const struct bb_applet *a,
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else
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putchar('\n'); /* bash does this on Ctrl-C */
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return 0;
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#else
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return run_nofork_applet(a, argv);
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#endif
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}
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#endif
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/* run_pipe_real() starts all the jobs, but doesn't wait for anything
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* to finish. See checkjobs().
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@ -1564,7 +1637,9 @@ static int run_pipe_real(struct pipe *pi)
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const int single_fg = (pi->num_progs == 1 && pi->followup != PIPE_BG);
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nextin = 0;
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#if ENABLE_HUSH_INTERACTIVE
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pi->pgrp = -1;
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#endif
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pi->running_progs = 0;
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pi->stopped_progs = 0;
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@ -1691,6 +1766,7 @@ static int run_pipe_real(struct pipe *pi)
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if (!child->pid) { /* child */
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/* Every child adds itself to new process group
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* with pgid == pid of first child in pipe */
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#if ENABLE_HUSH_INTERACTIVE
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if (interactive_fd) {
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/* Don't do pgrp restore anymore on fatal signals */
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set_fatal_sighandler(SIG_DFL);
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@ -1702,6 +1778,7 @@ static int run_pipe_real(struct pipe *pi)
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tcsetpgrp(interactive_fd, pi->pgrp);
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}
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}
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#endif
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// in non-interactive case fatal sigs are already SIG_DFL
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close_all();
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if (nextin != 0) {
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@ -1728,9 +1805,11 @@ static int run_pipe_real(struct pipe *pi)
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pi->running_progs++;
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#if ENABLE_HUSH_INTERACTIVE
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/* Second and next children need to know pid of first one */
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if (pi->pgrp < 0)
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pi->pgrp = child->pid;
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#endif
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/* Don't check for errors. The child may be dead already,
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* in which case setpgid returns error code EACCES. */
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@ -1858,7 +1937,9 @@ static int run_list_real(struct pipe *pi)
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/* XXX check bash's behavior with nontrivial pipes */
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/* XXX compute jobid */
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/* XXX what does bash do with attempts to background builtins? */
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#if ENABLE_HUSH_INTERACTIVE
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insert_bg_job(pi);
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#endif
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rcode = EXIT_SUCCESS;
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} else {
|
||||
if (interactive_fd) {
|
||||
@ -1931,8 +2012,10 @@ static int free_pipe(struct pipe *pi, int indent)
|
||||
}
|
||||
free(pi->progs); /* children are an array, they get freed all at once */
|
||||
pi->progs = NULL;
|
||||
#if ENABLE_HUSH_INTERACTIVE
|
||||
free(pi->cmdtext);
|
||||
pi->cmdtext = NULL;
|
||||
#endif
|
||||
return ret_code;
|
||||
}
|
||||
|
||||
@ -3041,6 +3124,7 @@ static int parse_file_outer(FILE *f)
|
||||
return rcode;
|
||||
}
|
||||
|
||||
#if ENABLE_HUSH_INTERACTIVE
|
||||
/* 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 */
|
||||
@ -3055,7 +3139,7 @@ static void setup_job_control(void)
|
||||
/* If we were ran as 'hush &',
|
||||
* sleep until we are in the foreground. */
|
||||
while (tcgetpgrp(interactive_fd) != shell_pgrp) {
|
||||
/* Send TTIN to ourself (will stop us) */
|
||||
/* Send TTIN to ourself (should stop us) */
|
||||
kill(- shell_pgrp, SIGTTIN);
|
||||
shell_pgrp = getpgrp();
|
||||
}
|
||||
@ -3073,6 +3157,7 @@ static void setup_job_control(void)
|
||||
/* Grab control of the terminal. */
|
||||
tcsetpgrp(interactive_fd, getpid());
|
||||
}
|
||||
#endif
|
||||
|
||||
int hush_main(int argc, char **argv);
|
||||
int hush_main(int argc, char **argv)
|
||||
@ -3095,11 +3180,13 @@ int hush_main(int argc, char **argv)
|
||||
ifs = NULL;
|
||||
/* map[] is taken care of with call to update_ifs_map() */
|
||||
fake_mode = 0;
|
||||
interactive_fd = 0;
|
||||
close_me_head = NULL;
|
||||
#if ENABLE_HUSH_INTERACTIVE
|
||||
interactive_fd = 0;
|
||||
last_bg_pid = 0;
|
||||
job_list = NULL;
|
||||
last_jobid = 0;
|
||||
#endif
|
||||
|
||||
/* Initialize some more globals to non-zero values */
|
||||
set_cwd();
|
||||
@ -3154,6 +3241,7 @@ int hush_main(int argc, char **argv)
|
||||
#endif
|
||||
}
|
||||
}
|
||||
#if ENABLE_HUSH_INTERACTIVE
|
||||
/* A shell is interactive if the '-i' flag was given, or if all of
|
||||
* the following conditions are met:
|
||||
* no -c command
|
||||
@ -3180,7 +3268,6 @@ int hush_main(int argc, char **argv)
|
||||
// to (inadvertently) close/redirect it
|
||||
}
|
||||
}
|
||||
|
||||
debug_printf("\ninteractive_fd=%d\n", interactive_fd);
|
||||
if (interactive_fd) {
|
||||
/* Looks like they want an interactive shell */
|
||||
@ -3196,6 +3283,7 @@ int hush_main(int argc, char **argv)
|
||||
printf("Enter 'help' for a list of built-in commands.\n\n");
|
||||
#endif
|
||||
}
|
||||
#endif
|
||||
|
||||
if (argv[optind] == NULL) {
|
||||
opt = parse_file_outer(stdin);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user