1 /* The thing that makes children, remembers them, and contains wait loops. */
3 /* This file works under BSD, System V, minix, and Posix systems. It does
4 not implement job control. */
6 /* Copyright (C) 1987-2005 Free Software Foundation, Inc.
8 This file is part of GNU Bash, the Bourne Again SHell.
10 Bash is free software; you can redistribute it and/or modify it under
11 the terms of the GNU General Public License as published by the Free
12 Software Foundation; either version 2, or (at your option) any later
15 Bash is distributed in the hope that it will be useful, but WITHOUT ANY
16 WARRANTY; without even the implied warranty of MERCHANTABILITY or
17 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
20 You should have received a copy of the GNU General Public License along
21 with Bash; see the file COPYING. If not, write to the Free Software
22 Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
26 #include "bashtypes.h"
29 #if defined (HAVE_UNISTD_H)
37 #if defined (BUFFERED_INPUT)
41 /* Need to include this up here for *_TTY_DRIVER definitions. */
49 #include "builtins/builtext.h" /* for wait_builtin */
51 #define DEFAULT_CHILD_MAX 32
53 #if defined (_POSIX_VERSION) || !defined (HAVE_KILLPG)
54 # define killpg(pg, sig) kill(-(pg),(sig))
55 #endif /* USG || _POSIX_VERSION */
57 #if !defined (HAVE_SIGINTERRUPT) && !defined (HAVE_POSIX_SIGNALS)
58 # define siginterrupt(sig, code)
59 #endif /* !HAVE_SIGINTERRUPT && !HAVE_POSIX_SIGNALS */
61 #if defined (HAVE_WAITPID)
62 # define WAITPID(pid, statusp, options) waitpid (pid, statusp, options)
64 # define WAITPID(pid, statusp, options) wait (statusp)
65 #endif /* !HAVE_WAITPID */
67 /* Return the fd from which we are actually getting input. */
68 #define input_tty() (shell_tty != -1) ? shell_tty : fileno (stderr)
74 extern int interactive, interactive_shell, login_shell;
75 extern int subshell_environment;
76 extern int last_command_exit_value, last_command_exit_signal;
77 extern int interrupt_immediately;
78 extern sh_builtin_func_t *this_shell_builtin;
79 #if defined (HAVE_POSIX_SIGNALS)
80 extern sigset_t top_level_mask;
82 extern procenv_t wait_intr_buf;
83 extern int wait_signal_received;
85 pid_t last_made_pid = NO_PID;
86 pid_t last_asynchronous_pid = NO_PID;
88 /* Call this when you start making children. */
89 int already_making_children = 0;
91 /* The controlling tty for this shell. */
94 /* If this is non-zero, $LINES and $COLUMNS are reset after every process
95 exits from get_tty_state(). */
96 int check_window_size;
98 /* STATUS and FLAGS are only valid if pid != NO_PID
99 STATUS is only valid if (flags & PROC_RUNNING) == 0 */
102 int status; /* Exit status of PID or 128 + fatal signal number */
106 /* Values for proc_status.flags */
107 #define PROC_RUNNING 0x01
108 #define PROC_NOTIFIED 0x02
109 #define PROC_ASYNC 0x04
110 #define PROC_SIGNALED 0x10
112 /* Return values from find_status_by_pid */
114 #define PROC_STILL_ALIVE -2
116 static struct proc_status *pid_list = (struct proc_status *)NULL;
117 static int pid_list_size;
118 static int wait_sigint_received;
120 static long child_max = -1L;
122 static void alloc_pid_list __P((void));
123 static int find_proc_slot __P((void));
124 static int find_index_by_pid __P((pid_t));
125 static int find_status_by_pid __P((pid_t));
126 static int process_exit_status __P((WAIT));
127 static int find_termsig_by_pid __P((pid_t));
128 static int get_termsig __P((WAIT));
129 static void set_pid_status __P((pid_t, WAIT));
130 static void set_pid_flags __P((pid_t, int));
131 static void unset_pid_flags __P((pid_t, int));
132 static int get_pid_flags __P((pid_t));
133 static void add_pid __P((pid_t, int));
134 static void mark_dead_jobs_as_notified __P((int));
136 static sighandler wait_sigint_handler __P((int));
137 static char *j_strsignal __P((int));
139 #if defined (HAVE_WAITPID)
140 static void reap_zombie_children __P((void));
143 #if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS)
144 static int siginterrupt __P((int, int));
147 static void restore_sigint_handler __P((void));
149 /* Allocate new, or grow existing PID_LIST. */
154 int old = pid_list_size;
157 pid_list = (struct proc_status *)xrealloc (pid_list, pid_list_size * sizeof (struct proc_status));
159 /* None of the newly allocated slots have process id's yet. */
160 for (i = old; i < pid_list_size; i++)
161 pid_list[i].pid = NO_PID;
164 /* Return the offset within the PID_LIST array of an empty slot. This can
165 create new slots if all of the existing slots are taken. */
171 for (i = 0; i < pid_list_size; i++)
172 if (pid_list[i].pid == NO_PID)
175 if (i == pid_list_size)
181 /* Return the offset within the PID_LIST array of a slot containing PID,
182 or the value NO_PID if the pid wasn't found. */
184 find_index_by_pid (pid)
189 for (i = 0; i < pid_list_size; i++)
190 if (pid_list[i].pid == pid)
196 /* Return the status of PID as looked up in the PID_LIST array. A
197 return value of PROC_BAD indicates that PID wasn't found. */
199 find_status_by_pid (pid)
204 i = find_index_by_pid (pid);
207 if (pid_list[i].flags & PROC_RUNNING)
208 return (PROC_STILL_ALIVE);
209 return (pid_list[i].status);
213 process_exit_status (status)
216 if (WIFSIGNALED (status))
217 return (128 + WTERMSIG (status));
219 return (WEXITSTATUS (status));
222 /* Return the status of PID as looked up in the PID_LIST array. A
223 return value of PROC_BAD indicates that PID wasn't found. */
225 find_termsig_by_pid (pid)
230 i = find_index_by_pid (pid);
233 if (pid_list[i].flags & PROC_RUNNING)
235 return (get_termsig (pid_list[i].status));
238 /* Set LAST_COMMAND_EXIT_SIGNAL depending on STATUS. If STATUS is -1, look
239 up PID in the pid array and set LAST_COMMAND_EXIT_SIGNAL appropriately
240 depending on its flags and exit status. */
245 if (WIFSTOPPED (status) == 0 && WIFSIGNALED (status))
246 return (WTERMSIG (status));
251 /* Give PID the status value STATUS in the PID_LIST array. */
253 set_pid_status (pid, status)
259 slot = find_index_by_pid (pid);
263 pid_list[slot].status = process_exit_status (status);
264 pid_list[slot].flags &= ~PROC_RUNNING;
265 if (WIFSIGNALED (status))
266 pid_list[slot].flags |= PROC_SIGNALED;
267 /* If it's not a background process, mark it as notified so it gets
269 if ((pid_list[slot].flags & PROC_ASYNC) == 0)
270 pid_list[slot].flags |= PROC_NOTIFIED;
273 /* Give PID the flags FLAGS in the PID_LIST array. */
275 set_pid_flags (pid, flags)
281 slot = find_index_by_pid (pid);
285 pid_list[slot].flags |= flags;
288 /* Unset FLAGS for PID in the pid list */
290 unset_pid_flags (pid, flags)
296 slot = find_index_by_pid (pid);
300 pid_list[slot].flags &= ~flags;
303 /* Return the flags corresponding to PID in the PID_LIST array. */
310 slot = find_index_by_pid (pid);
314 return (pid_list[slot].flags);
324 slot = find_proc_slot ();
326 pid_list[slot].pid = pid;
327 pid_list[slot].status = -1;
328 pid_list[slot].flags = PROC_RUNNING;
330 pid_list[slot].flags |= PROC_ASYNC;
334 mark_dead_jobs_as_notified (force)
337 register int i, ndead;
339 /* first, count the number of non-running async jobs if FORCE == 0 */
340 for (i = ndead = 0; force == 0 && i < pid_list_size; i++)
342 if (pid_list[i].pid == NO_PID)
344 if (((pid_list[i].flags & PROC_RUNNING) == 0) &&
345 (pid_list[i].flags & PROC_ASYNC))
350 child_max = getmaxchild ();
352 child_max = DEFAULT_CHILD_MAX;
354 if (force == 0 && ndead <= child_max)
357 /* If FORCE == 0, we just mark as many non-running async jobs as notified
358 to bring us under the CHILD_MAX limit. */
359 for (i = 0; i < pid_list_size; i++)
361 if (pid_list[i].pid == NO_PID)
363 if (((pid_list[i].flags & PROC_RUNNING) == 0) &&
364 pid_list[i].pid != last_asynchronous_pid)
366 pid_list[i].flags |= PROC_NOTIFIED;
367 if (force == 0 && (pid_list[i].flags & PROC_ASYNC) && --ndead <= child_max)
373 /* Remove all dead, notified jobs from the pid_list. */
379 #if defined (HAVE_WAITPID)
380 reap_zombie_children ();
383 for (i = 0; i < pid_list_size; i++)
385 if ((pid_list[i].flags & PROC_RUNNING) == 0 &&
386 (pid_list[i].flags & PROC_NOTIFIED))
387 pid_list[i].pid = NO_PID;
396 mark_dead_jobs_as_notified (0);
397 cleanup_dead_jobs ();
400 /* Initialize the job control mechanism, and set up the tty stuff. */
401 initialize_job_control (force)
404 shell_tty = fileno (stderr);
410 /* Setup this shell to handle C-C, etc. */
412 initialize_job_signals ()
414 set_signal_handler (SIGINT, sigint_sighandler);
416 /* If this is a login shell we don't wish to be disturbed by
419 ignore_tty_job_signals ();
422 #if defined (HAVE_WAITPID)
423 /* Collect the status of all zombie children so that their system
424 resources can be deallocated. */
426 reap_zombie_children ()
428 # if defined (WNOHANG)
432 while ((pid = waitpid (-1, (int *)&status, WNOHANG)) > 0)
433 set_pid_status (pid, status);
434 # endif /* WNOHANG */
438 #if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS)
440 siginterrupt (sig, flag)
443 struct sigaction act;
445 sigaction (sig, (struct sigaction *)NULL, &act);
448 act.sa_flags &= ~SA_RESTART;
450 act.sa_flags |= SA_RESTART;
452 return (sigaction (sig, &act, (struct sigaction *)NULL));
454 #endif /* !HAVE_SIGINTERRUPT && HAVE_POSIX_SIGNALS */
456 /* Fork, handling errors. Returns the pid of the newly made child, or 0.
457 COMMAND is just for remembering the name of the command; we don't do
458 anything else with it. ASYNC_P says what to do with the tty. If
459 non-zero, then don't give it away. */
461 make_child (command, async_p)
466 #if defined (HAVE_WAITPID)
468 #endif /* HAVE_WAITPID */
470 /* Discard saved memory. */
476 #if defined (BUFFERED_INPUT)
477 /* If default_buffered_input is active, we are reading a script. If
478 the command is asynchronous, we have already duplicated /dev/null
479 as fd 0, but have not changed the buffered stream corresponding to
480 the old fd 0. We don't want to sync the stream in this case. */
481 if (default_buffered_input != -1 && (!async_p || default_buffered_input > 0))
482 sync_buffered_stream (default_buffered_input);
483 #endif /* BUFFERED_INPUT */
485 /* Create the child, handle severe errors. */
486 #if defined (HAVE_WAITPID)
488 #endif /* HAVE_WAITPID */
490 if ((pid = fork ()) < 0)
492 #if defined (HAVE_WAITPID)
493 /* Posix systems with a non-blocking waitpid () system call available
494 get another chance after zombies are reaped. */
495 if (errno == EAGAIN && retry)
497 reap_zombie_children ();
501 #endif /* HAVE_WAITPID */
505 throw_to_top_level ();
510 #if defined (BUFFERED_INPUT)
511 unset_bash_input (0);
512 #endif /* BUFFERED_INPUT */
514 #if defined (HAVE_POSIX_SIGNALS)
515 /* Restore top-level signal mask. */
516 sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL);
519 /* Ignore INT and QUIT in asynchronous children. */
521 last_asynchronous_pid = getpid ();
523 default_tty_job_signals ();
532 last_asynchronous_pid = pid;
534 add_pid (pid, async_p);
540 ignore_tty_job_signals ()
542 #if defined (SIGTSTP)
543 set_signal_handler (SIGTSTP, SIG_IGN);
544 set_signal_handler (SIGTTIN, SIG_IGN);
545 set_signal_handler (SIGTTOU, SIG_IGN);
550 default_tty_job_signals ()
552 #if defined (SIGTSTP)
553 set_signal_handler (SIGTSTP, SIG_DFL);
554 set_signal_handler (SIGTTIN, SIG_DFL);
555 set_signal_handler (SIGTTOU, SIG_DFL);
559 /* Wait for a single pid (PID) and return its exit status. Called by
562 wait_for_single_pid (pid)
569 pstatus = find_status_by_pid (pid);
571 if (pstatus == PROC_BAD)
573 internal_error (_("wait: pid %ld is not a child of this shell"), (long)pid);
577 if (pstatus != PROC_STILL_ALIVE)
580 last_command_exit_signal = find_termsig_by_pid (pid);
584 siginterrupt (SIGINT, 1);
585 while ((got_pid = WAITPID (pid, &status, 0)) != pid)
589 if (errno != EINTR && errno != ECHILD)
591 siginterrupt (SIGINT, 0);
596 else if (got_pid > 0)
597 set_pid_status (got_pid, status);
602 set_pid_status (got_pid, status);
603 set_pid_flags (got_pid, PROC_NOTIFIED);
606 siginterrupt (SIGINT, 0);
609 return (got_pid > 0 ? process_exit_status (status) : -1);
612 /* Wait for all of the shell's children to exit. Called by the `wait'
615 wait_for_background_pids ()
620 /* If we aren't using job control, we let the kernel take care of the
621 bookkeeping for us. wait () will return -1 and set errno to ECHILD
622 when there are no more unwaited-for child processes on both
623 4.2 BSD-based and System V-based systems. */
625 siginterrupt (SIGINT, 1);
627 /* Wait for ECHILD */
628 while ((got_pid = WAITPID (-1, &status, 0)) != -1)
629 set_pid_status (got_pid, status);
631 if (errno != EINTR && errno != ECHILD)
633 siginterrupt (SIGINT, 0);
637 siginterrupt (SIGINT, 0);
640 mark_dead_jobs_as_notified (1);
641 cleanup_dead_jobs ();
644 /* Make OLD_SIGINT_HANDLER the SIGINT signal handler. */
645 #define INVALID_SIGNAL_HANDLER (SigHandler *)wait_for_background_pids
646 static SigHandler *old_sigint_handler = INVALID_SIGNAL_HANDLER;
649 restore_sigint_handler ()
651 if (old_sigint_handler != INVALID_SIGNAL_HANDLER)
653 set_signal_handler (SIGINT, old_sigint_handler);
654 old_sigint_handler = INVALID_SIGNAL_HANDLER;
658 /* Handle SIGINT while we are waiting for children in a script to exit.
659 All interrupts are effectively ignored by the shell, but allowed to
660 kill a running job. */
662 wait_sigint_handler (sig)
665 SigHandler *sigint_handler;
667 /* If we got a SIGINT while in `wait', and SIGINT is trapped, do
668 what POSIX.2 says (see builtins/wait.def for more info). */
669 if (this_shell_builtin && this_shell_builtin == wait_builtin &&
670 signal_is_trapped (SIGINT) &&
671 ((sigint_handler = trap_to_sighandler (SIGINT)) == trap_handler))
673 last_command_exit_value = EXECUTION_FAILURE;
674 restore_sigint_handler ();
675 interrupt_immediately = 0;
676 trap_handler (SIGINT); /* set pending_traps[SIGINT] */
677 wait_signal_received = SIGINT;
678 longjmp (wait_intr_buf, 1);
681 if (interrupt_immediately)
683 last_command_exit_value = EXECUTION_FAILURE;
684 restore_sigint_handler ();
689 wait_sigint_received = 1;
698 static char retcode_name_buffer[64] = { '\0' };
704 x = retcode_name_buffer;
705 sprintf (x, "Signal %d", s);
710 /* Wait for pid (one of our children) to terminate. This is called only
711 by the execution code in execute_cmd.c. */
716 int return_val, pstatus;
720 pstatus = find_status_by_pid (pid);
722 if (pstatus == PROC_BAD)
725 if (pstatus != PROC_STILL_ALIVE)
728 last_command_exit_signal = find_termsig_by_pid (pid);
732 /* If we are running a script, ignore SIGINT while we're waiting for
733 a child to exit. The loop below does some of this, but not all. */
734 wait_sigint_received = 0;
735 if (interactive_shell == 0)
736 old_sigint_handler = set_signal_handler (SIGINT, wait_sigint_handler);
738 while ((got_pid = WAITPID (-1, &status, 0)) != pid) /* XXX was pid now -1 */
740 if (got_pid < 0 && errno == ECHILD)
742 #if !defined (_POSIX_VERSION)
743 status.w_termsig = status.w_retcode = 0;
746 #endif /* _POSIX_VERSION */
749 else if (got_pid < 0 && errno != EINTR)
750 programming_error ("wait_for(%ld): %s", (long)pid, strerror(errno));
751 else if (got_pid > 0)
752 set_pid_status (got_pid, status);
756 set_pid_status (got_pid, status);
758 #if defined (HAVE_WAITPID)
760 reap_zombie_children ();
761 #endif /* HAVE_WAITPID */
763 if (interactive_shell == 0)
765 SigHandler *temp_handler;
767 temp_handler = old_sigint_handler;
768 restore_sigint_handler ();
770 /* If the job exited because of SIGINT, make sure the shell acts as if
771 it had received one also. */
772 if (WIFSIGNALED (status) && (WTERMSIG (status) == SIGINT))
775 if (maybe_call_trap_handler (SIGINT) == 0)
777 if (temp_handler == SIG_DFL)
778 termination_unwind_protect (SIGINT);
779 else if (temp_handler != INVALID_SIGNAL_HANDLER && temp_handler != SIG_IGN)
780 (*temp_handler) (SIGINT);
785 /* Default return value. */
786 /* ``a full 8 bits of status is returned'' */
787 return_val = process_exit_status (status);
788 last_command_exit_signal = get_termsig (status);
790 #if !defined (DONT_REPORT_SIGPIPE)
791 if ((WIFSTOPPED (status) == 0) && WIFSIGNALED (status) &&
792 (WTERMSIG (status) != SIGINT))
794 if ((WIFSTOPPED (status) == 0) && WIFSIGNALED (status) &&
795 (WTERMSIG (status) != SIGINT) && (WTERMSIG (status) != SIGPIPE))
798 fprintf (stderr, "%s", j_strsignal (WTERMSIG (status)));
799 if (WIFCORED (status))
800 fprintf (stderr, " (core dumped)");
801 fprintf (stderr, "\n");
804 if (interactive_shell && subshell_environment == 0)
806 if (WIFSIGNALED (status) || WIFSTOPPED (status))
815 /* Send PID SIGNAL. Returns -1 on failure, 0 on success. If GROUP is non-zero,
816 or PID is less than -1, then kill the process group associated with PID. */
818 kill_pid (pid, signal, group)
829 result = group ? killpg (pid, signal) : kill (pid, signal);
833 static TTYSTRUCT shell_tty_info;
834 static int got_tty_state;
836 /* Fill the contents of shell_tty_info with the current tty info. */
844 ttgetattr (tty, &shell_tty_info);
846 if (check_window_size)
847 get_new_window_size (0, (int *)0, (int *)0);
851 /* Make the current tty use the state in shell_tty_info. */
860 if (got_tty_state == 0)
862 ttsetattr (tty, &shell_tty_info);
867 /* Give the terminal to PGRP. */
868 give_terminal_to (pgrp, force)
874 /* Stop a pipeline. */
876 stop_pipeline (async, ignore)
880 already_making_children = 0;
887 already_making_children = 1;
891 stop_making_children ()
893 already_making_children = 0;
897 get_job_by_pid (pid, block)
903 i = find_index_by_pid (pid);
904 return ((i == NO_PID) ? PROC_BAD : i);
907 /* Print descriptive information about the job with leader pid PID. */
912 fprintf (stderr, "%ld\n", (long) pid);
916 unfreeze_jobs_list ()