1 /* nojobs.c - functions that make children, remember them, and handle their termination. */
3 /* This file works under BSD, System V, minix, and Posix systems. It does
4 not implement job control. */
6 /* Copyright (C) 1987-2011 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
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation, either version 3 of the License, or
13 (at your option) any later version.
15 Bash is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with Bash. If not, see <http://www.gnu.org/licenses/>.
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. */
48 #include "execute_cmd.h"
50 #include "builtins/builtext.h" /* for wait_builtin */
52 #define DEFAULT_CHILD_MAX 32
54 #if defined (_POSIX_VERSION) || !defined (HAVE_KILLPG)
55 # define killpg(pg, sig) kill(-(pg),(sig))
56 #endif /* USG || _POSIX_VERSION */
58 #if !defined (HAVE_SIGINTERRUPT) && !defined (HAVE_POSIX_SIGNALS)
59 # define siginterrupt(sig, code)
60 #endif /* !HAVE_SIGINTERRUPT && !HAVE_POSIX_SIGNALS */
62 #if defined (HAVE_WAITPID)
63 # define WAITPID(pid, statusp, options) waitpid (pid, statusp, options)
65 # define WAITPID(pid, statusp, options) wait (statusp)
66 #endif /* !HAVE_WAITPID */
68 /* Return the fd from which we are actually getting input. */
69 #define input_tty() (shell_tty != -1) ? shell_tty : fileno (stderr)
75 extern int interactive, interactive_shell, login_shell;
76 extern int subshell_environment;
77 extern int last_command_exit_value, last_command_exit_signal;
78 extern int interrupt_immediately;
79 extern sh_builtin_func_t *this_shell_builtin;
80 #if defined (HAVE_POSIX_SIGNALS)
81 extern sigset_t top_level_mask;
83 extern procenv_t wait_intr_buf;
84 extern int wait_signal_received;
86 volatile pid_t last_made_pid = NO_PID;
87 volatile pid_t last_asynchronous_pid = NO_PID;
89 /* Call this when you start making children. */
90 int already_making_children = 0;
92 /* The controlling tty for this shell. */
95 /* If this is non-zero, $LINES and $COLUMNS are reset after every process
96 exits from get_tty_state(). */
97 int check_window_size = CHECKWINSIZE_DEFAULT;
99 /* We don't have job control. */
102 /* STATUS and FLAGS are only valid if pid != NO_PID
103 STATUS is only valid if (flags & PROC_RUNNING) == 0 */
106 int status; /* Exit status of PID or 128 + fatal signal number */
110 /* Values for proc_status.flags */
111 #define PROC_RUNNING 0x01
112 #define PROC_NOTIFIED 0x02
113 #define PROC_ASYNC 0x04
114 #define PROC_SIGNALED 0x10
116 /* Return values from find_status_by_pid */
118 #define PROC_STILL_ALIVE -2
120 static struct proc_status *pid_list = (struct proc_status *)NULL;
121 static int pid_list_size;
122 static int wait_sigint_received;
124 static long child_max = -1L;
126 static void alloc_pid_list __P((void));
127 static int find_proc_slot __P((void));
128 static int find_index_by_pid __P((pid_t));
129 static int find_status_by_pid __P((pid_t));
130 static int process_exit_status __P((WAIT));
131 static int find_termsig_by_pid __P((pid_t));
132 static int get_termsig __P((WAIT));
133 static void set_pid_status __P((pid_t, WAIT));
134 static void set_pid_flags __P((pid_t, int));
135 static void unset_pid_flags __P((pid_t, int));
136 static int get_pid_flags __P((pid_t));
137 static void add_pid __P((pid_t, int));
138 static void mark_dead_jobs_as_notified __P((int));
140 static sighandler wait_sigint_handler __P((int));
141 static char *j_strsignal __P((int));
143 #if defined (HAVE_WAITPID)
144 static void reap_zombie_children __P((void));
147 #if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS)
148 static int siginterrupt __P((int, int));
151 static void restore_sigint_handler __P((void));
153 /* Allocate new, or grow existing PID_LIST. */
158 int old = pid_list_size;
161 pid_list = (struct proc_status *)xrealloc (pid_list, pid_list_size * sizeof (struct proc_status));
163 /* None of the newly allocated slots have process id's yet. */
164 for (i = old; i < pid_list_size; i++)
165 pid_list[i].pid = NO_PID;
168 /* Return the offset within the PID_LIST array of an empty slot. This can
169 create new slots if all of the existing slots are taken. */
175 for (i = 0; i < pid_list_size; i++)
176 if (pid_list[i].pid == NO_PID)
179 if (i == pid_list_size)
185 /* Return the offset within the PID_LIST array of a slot containing PID,
186 or the value NO_PID if the pid wasn't found. */
188 find_index_by_pid (pid)
193 for (i = 0; i < pid_list_size; i++)
194 if (pid_list[i].pid == pid)
200 /* Return the status of PID as looked up in the PID_LIST array. A
201 return value of PROC_BAD indicates that PID wasn't found. */
203 find_status_by_pid (pid)
208 i = find_index_by_pid (pid);
211 if (pid_list[i].flags & PROC_RUNNING)
212 return (PROC_STILL_ALIVE);
213 return (pid_list[i].status);
217 process_exit_status (status)
220 if (WIFSIGNALED (status))
221 return (128 + WTERMSIG (status));
223 return (WEXITSTATUS (status));
226 /* Return the status of PID as looked up in the PID_LIST array. A
227 return value of PROC_BAD indicates that PID wasn't found. */
229 find_termsig_by_pid (pid)
234 i = find_index_by_pid (pid);
237 if (pid_list[i].flags & PROC_RUNNING)
239 return (get_termsig ((WAIT)pid_list[i].status));
242 /* Set LAST_COMMAND_EXIT_SIGNAL depending on STATUS. If STATUS is -1, look
243 up PID in the pid array and set LAST_COMMAND_EXIT_SIGNAL appropriately
244 depending on its flags and exit status. */
249 if (WIFSTOPPED (status) == 0 && WIFSIGNALED (status))
250 return (WTERMSIG (status));
255 /* Give PID the status value STATUS in the PID_LIST array. */
257 set_pid_status (pid, status)
263 #if defined (COPROCESS_SUPPORT)
264 coproc_pidchk (pid, status);
267 slot = find_index_by_pid (pid);
271 pid_list[slot].status = process_exit_status (status);
272 pid_list[slot].flags &= ~PROC_RUNNING;
273 if (WIFSIGNALED (status))
274 pid_list[slot].flags |= PROC_SIGNALED;
275 /* If it's not a background process, mark it as notified so it gets
277 if ((pid_list[slot].flags & PROC_ASYNC) == 0)
278 pid_list[slot].flags |= PROC_NOTIFIED;
281 /* Give PID the flags FLAGS in the PID_LIST array. */
283 set_pid_flags (pid, flags)
289 slot = find_index_by_pid (pid);
293 pid_list[slot].flags |= flags;
296 /* Unset FLAGS for PID in the pid list */
298 unset_pid_flags (pid, flags)
304 slot = find_index_by_pid (pid);
308 pid_list[slot].flags &= ~flags;
311 /* Return the flags corresponding to PID in the PID_LIST array. */
318 slot = find_index_by_pid (pid);
322 return (pid_list[slot].flags);
332 slot = find_proc_slot ();
334 pid_list[slot].pid = pid;
335 pid_list[slot].status = -1;
336 pid_list[slot].flags = PROC_RUNNING;
338 pid_list[slot].flags |= PROC_ASYNC;
342 mark_dead_jobs_as_notified (force)
345 register int i, ndead;
347 /* first, count the number of non-running async jobs if FORCE == 0 */
348 for (i = ndead = 0; force == 0 && i < pid_list_size; i++)
350 if (pid_list[i].pid == NO_PID)
352 if (((pid_list[i].flags & PROC_RUNNING) == 0) &&
353 (pid_list[i].flags & PROC_ASYNC))
358 child_max = getmaxchild ();
360 child_max = DEFAULT_CHILD_MAX;
362 if (force == 0 && ndead <= child_max)
365 /* If FORCE == 0, we just mark as many non-running async jobs as notified
366 to bring us under the CHILD_MAX limit. */
367 for (i = 0; i < pid_list_size; i++)
369 if (pid_list[i].pid == NO_PID)
371 if (((pid_list[i].flags & PROC_RUNNING) == 0) &&
372 pid_list[i].pid != last_asynchronous_pid)
374 pid_list[i].flags |= PROC_NOTIFIED;
375 if (force == 0 && (pid_list[i].flags & PROC_ASYNC) && --ndead <= child_max)
381 /* Remove all dead, notified jobs from the pid_list. */
387 #if defined (HAVE_WAITPID)
388 reap_zombie_children ();
391 for (i = 0; i < pid_list_size; i++)
393 if ((pid_list[i].flags & PROC_RUNNING) == 0 &&
394 (pid_list[i].flags & PROC_NOTIFIED))
395 pid_list[i].pid = NO_PID;
398 #if defined (COPROCESS_SUPPORT)
408 mark_dead_jobs_as_notified (0);
409 cleanup_dead_jobs ();
412 /* Initialize the job control mechanism, and set up the tty stuff. */
413 initialize_job_control (force)
416 shell_tty = fileno (stderr);
422 /* Setup this shell to handle C-C, etc. */
424 initialize_job_signals ()
426 set_signal_handler (SIGINT, sigint_sighandler);
428 /* If this is a login shell we don't wish to be disturbed by
431 ignore_tty_job_signals ();
434 #if defined (HAVE_WAITPID)
435 /* Collect the status of all zombie children so that their system
436 resources can be deallocated. */
438 reap_zombie_children ()
440 # if defined (WNOHANG)
446 while ((pid = waitpid (-1, (int *)&status, WNOHANG)) > 0)
447 set_pid_status (pid, status);
448 # endif /* WNOHANG */
454 #if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS)
456 #if !defined (SA_RESTART)
457 # define SA_RESTART 0
461 siginterrupt (sig, flag)
464 struct sigaction act;
466 sigaction (sig, (struct sigaction *)NULL, &act);
469 act.sa_flags &= ~SA_RESTART;
471 act.sa_flags |= SA_RESTART;
473 return (sigaction (sig, &act, (struct sigaction *)NULL));
475 #endif /* !HAVE_SIGINTERRUPT && HAVE_POSIX_SIGNALS */
477 /* Fork, handling errors. Returns the pid of the newly made child, or 0.
478 COMMAND is just for remembering the name of the command; we don't do
479 anything else with it. ASYNC_P says what to do with the tty. If
480 non-zero, then don't give it away. */
482 make_child (command, async_p)
489 /* Discard saved memory. */
495 #if defined (BUFFERED_INPUT)
496 /* If default_buffered_input is active, we are reading a script. If
497 the command is asynchronous, we have already duplicated /dev/null
498 as fd 0, but have not changed the buffered stream corresponding to
499 the old fd 0. We don't want to sync the stream in this case. */
500 if (default_buffered_input != -1 && (!async_p || default_buffered_input > 0))
501 sync_buffered_stream (default_buffered_input);
502 #endif /* BUFFERED_INPUT */
504 /* XXX - block SIGTERM here and unblock in child after fork resets the
505 set of pending signals? */
508 /* Create the child, handle severe errors. Retry on EAGAIN. */
510 while ((pid = fork ()) < 0 && errno == EAGAIN && forksleep < FORKSLEEP_MAX)
512 sys_error ("fork: retry");
515 #if defined (HAVE_WAITPID)
516 /* Posix systems with a non-blocking waitpid () system call available
517 get another chance after zombies are reaped. */
518 reap_zombie_children ();
519 if (forksleep > 1 && sleep (forksleep) != 0)
522 if (sleep (forksleep) != 0)
524 #endif /* HAVE_WAITPID */
534 last_command_exit_value = EX_NOEXEC;
535 throw_to_top_level ();
540 #if defined (BUFFERED_INPUT)
541 unset_bash_input (0);
542 #endif /* BUFFERED_INPUT */
544 #if defined (HAVE_POSIX_SIGNALS)
545 /* Restore top-level signal mask. */
546 sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL);
550 /* Ignore INT and QUIT in asynchronous children. */
552 last_asynchronous_pid = getpid ();
555 default_tty_job_signals ();
564 last_asynchronous_pid = pid;
566 add_pid (pid, async_p);
572 ignore_tty_job_signals ()
574 #if defined (SIGTSTP)
575 set_signal_handler (SIGTSTP, SIG_IGN);
576 set_signal_handler (SIGTTIN, SIG_IGN);
577 set_signal_handler (SIGTTOU, SIG_IGN);
582 default_tty_job_signals ()
584 #if defined (SIGTSTP)
585 set_signal_handler (SIGTSTP, SIG_DFL);
586 set_signal_handler (SIGTTIN, SIG_DFL);
587 set_signal_handler (SIGTTOU, SIG_DFL);
591 /* Wait for a single pid (PID) and return its exit status. Called by
594 wait_for_single_pid (pid)
601 pstatus = find_status_by_pid (pid);
603 if (pstatus == PROC_BAD)
605 internal_error (_("wait: pid %ld is not a child of this shell"), (long)pid);
609 if (pstatus != PROC_STILL_ALIVE)
612 last_command_exit_signal = find_termsig_by_pid (pid);
616 siginterrupt (SIGINT, 1);
617 while ((got_pid = WAITPID (pid, &status, 0)) != pid)
623 if (errno != EINTR && errno != ECHILD)
625 siginterrupt (SIGINT, 0);
630 else if (got_pid > 0)
631 set_pid_status (got_pid, status);
636 set_pid_status (got_pid, status);
637 set_pid_flags (got_pid, PROC_NOTIFIED);
640 siginterrupt (SIGINT, 0);
643 return (got_pid > 0 ? process_exit_status (status) : -1);
646 /* Wait for all of the shell's children to exit. Called by the `wait'
649 wait_for_background_pids ()
654 /* If we aren't using job control, we let the kernel take care of the
655 bookkeeping for us. wait () will return -1 and set errno to ECHILD
656 when there are no more unwaited-for child processes on both
657 4.2 BSD-based and System V-based systems. */
659 siginterrupt (SIGINT, 1);
661 /* Wait for ECHILD */
662 while ((got_pid = WAITPID (-1, &status, 0)) != -1)
663 set_pid_status (got_pid, status);
665 if (errno != EINTR && errno != ECHILD)
667 siginterrupt (SIGINT, 0);
671 siginterrupt (SIGINT, 0);
674 mark_dead_jobs_as_notified (1);
675 cleanup_dead_jobs ();
678 /* Make OLD_SIGINT_HANDLER the SIGINT signal handler. */
679 #define INVALID_SIGNAL_HANDLER (SigHandler *)wait_for_background_pids
680 static SigHandler *old_sigint_handler = INVALID_SIGNAL_HANDLER;
683 restore_sigint_handler ()
685 if (old_sigint_handler != INVALID_SIGNAL_HANDLER)
687 set_signal_handler (SIGINT, old_sigint_handler);
688 old_sigint_handler = INVALID_SIGNAL_HANDLER;
692 /* Handle SIGINT while we are waiting for children in a script to exit.
693 All interrupts are effectively ignored by the shell, but allowed to
694 kill a running job. */
696 wait_sigint_handler (sig)
699 SigHandler *sigint_handler;
701 /* If we got a SIGINT while in `wait', and SIGINT is trapped, do
702 what POSIX.2 says (see builtins/wait.def for more info). */
703 if (this_shell_builtin && this_shell_builtin == wait_builtin &&
704 signal_is_trapped (SIGINT) &&
705 ((sigint_handler = trap_to_sighandler (SIGINT)) == trap_handler))
707 last_command_exit_value = 128+SIGINT;
708 restore_sigint_handler ();
709 interrupt_immediately = 0;
710 trap_handler (SIGINT); /* set pending_traps[SIGINT] */
711 wait_signal_received = SIGINT;
715 if (interrupt_immediately)
717 last_command_exit_value = EXECUTION_FAILURE;
718 restore_sigint_handler ();
723 wait_sigint_received = 1;
732 static char retcode_name_buffer[64] = { '\0' };
738 x = retcode_name_buffer;
739 sprintf (x, "Signal %d", s);
744 /* Wait for pid (one of our children) to terminate. This is called only
745 by the execution code in execute_cmd.c. */
750 int return_val, pstatus;
754 pstatus = find_status_by_pid (pid);
756 if (pstatus == PROC_BAD)
759 if (pstatus != PROC_STILL_ALIVE)
762 last_command_exit_signal = find_termsig_by_pid (pid);
766 /* If we are running a script, ignore SIGINT while we're waiting for
767 a child to exit. The loop below does some of this, but not all. */
768 wait_sigint_received = 0;
769 if (interactive_shell == 0)
770 old_sigint_handler = set_signal_handler (SIGINT, wait_sigint_handler);
772 while ((got_pid = WAITPID (-1, &status, 0)) != pid) /* XXX was pid now -1 */
776 if (got_pid < 0 && errno == ECHILD)
778 #if !defined (_POSIX_VERSION)
779 status.w_termsig = status.w_retcode = 0;
782 #endif /* _POSIX_VERSION */
785 else if (got_pid < 0 && errno != EINTR)
786 programming_error ("wait_for(%ld): %s", (long)pid, strerror(errno));
787 else if (got_pid > 0)
788 set_pid_status (got_pid, status);
792 set_pid_status (got_pid, status);
794 #if defined (HAVE_WAITPID)
796 reap_zombie_children ();
797 #endif /* HAVE_WAITPID */
802 if (interactive_shell == 0)
804 SigHandler *temp_handler;
806 temp_handler = old_sigint_handler;
807 restore_sigint_handler ();
809 /* If the job exited because of SIGINT, make sure the shell acts as if
810 it had received one also. */
811 if (WIFSIGNALED (status) && (WTERMSIG (status) == SIGINT))
814 if (maybe_call_trap_handler (SIGINT) == 0)
816 if (temp_handler == SIG_DFL)
817 termsig_handler (SIGINT);
818 else if (temp_handler != INVALID_SIGNAL_HANDLER && temp_handler != SIG_IGN)
819 (*temp_handler) (SIGINT);
824 /* Default return value. */
825 /* ``a full 8 bits of status is returned'' */
826 return_val = process_exit_status (status);
827 last_command_exit_signal = get_termsig (status);
829 #if defined (DONT_REPORT_SIGPIPE) && defined (DONT_REPORT_SIGTERM)
830 # define REPORTSIG(x) ((x) != SIGINT && (x) != SIGPIPE && (x) != SIGTERM)
831 #elif !defined (DONT_REPORT_SIGPIPE) && !defined (DONT_REPORT_SIGTERM)
832 # define REPORTSIG(x) ((x) != SIGINT)
833 #elif defined (DONT_REPORT_SIGPIPE)
834 # define REPORTSIG(x) ((x) != SIGINT && (x) != SIGPIPE)
836 # define REPORTSIG(x) ((x) != SIGINT && (x) != SIGTERM)
839 if ((WIFSTOPPED (status) == 0) && WIFSIGNALED (status) && REPORTSIG(WTERMSIG (status)))
841 fprintf (stderr, "%s", j_strsignal (WTERMSIG (status)));
842 if (WIFCORED (status))
843 fprintf (stderr, _(" (core dumped)"));
844 fprintf (stderr, "\n");
847 if (interactive_shell && subshell_environment == 0)
849 if (WIFSIGNALED (status) || WIFSTOPPED (status))
854 else if (interactive_shell == 0 && subshell_environment == 0 && check_window_size)
855 get_new_window_size (0, (int *)0, (int *)0);
860 /* Send PID SIGNAL. Returns -1 on failure, 0 on success. If GROUP is non-zero,
861 or PID is less than -1, then kill the process group associated with PID. */
863 kill_pid (pid, signal, group)
874 result = group ? killpg (pid, signal) : kill (pid, signal);
878 static TTYSTRUCT shell_tty_info;
879 static int got_tty_state;
881 /* Fill the contents of shell_tty_info with the current tty info. */
889 ttgetattr (tty, &shell_tty_info);
891 if (check_window_size)
892 get_new_window_size (0, (int *)0, (int *)0);
896 /* Make the current tty use the state in shell_tty_info. */
905 if (got_tty_state == 0)
907 ttsetattr (tty, &shell_tty_info);
912 /* Give the terminal to PGRP. */
913 give_terminal_to (pgrp, force)
919 /* Stop a pipeline. */
921 stop_pipeline (async, ignore)
925 already_making_children = 0;
932 already_making_children = 1;
936 stop_making_children ()
938 already_making_children = 0;
942 get_job_by_pid (pid, block)
948 i = find_index_by_pid (pid);
949 return ((i == NO_PID) ? PROC_BAD : i);
952 /* Print descriptive information about the job with leader pid PID. */
957 fprintf (stderr, "%ld\n", (long) pid);
966 unfreeze_jobs_list ()