1/* The thing that makes children, remembers them, and contains wait loops. */
2
3/* This file works under BSD, System V, minix, and Posix systems.  It does
4   not implement job control. */
5
6/* Copyright (C) 1987-2006 Free Software Foundation, Inc.
7
8   This file is part of GNU Bash, the Bourne Again SHell.
9
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
13   version.
14
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
18   for more details.
19
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. */
23
24#include "config.h"
25
26#include "bashtypes.h"
27#include "filecntl.h"
28
29#if defined (HAVE_UNISTD_H)
30#  include <unistd.h>
31#endif
32
33#include <stdio.h>
34#include <signal.h>
35#include <errno.h>
36
37#if defined (BUFFERED_INPUT)
38#  include "input.h"
39#endif
40
41/* Need to include this up here for *_TTY_DRIVER definitions. */
42#include "shtty.h"
43
44#include "bashintl.h"
45
46#include "shell.h"
47#include "jobs.h"
48
49#include "builtins/builtext.h"	/* for wait_builtin */
50
51#define DEFAULT_CHILD_MAX 32
52
53#if defined (_POSIX_VERSION) || !defined (HAVE_KILLPG)
54#  define killpg(pg, sig)		kill(-(pg),(sig))
55#endif /* USG || _POSIX_VERSION */
56
57#if !defined (HAVE_SIGINTERRUPT) && !defined (HAVE_POSIX_SIGNALS)
58#  define siginterrupt(sig, code)
59#endif /* !HAVE_SIGINTERRUPT && !HAVE_POSIX_SIGNALS */
60
61#if defined (HAVE_WAITPID)
62#  define WAITPID(pid, statusp, options) waitpid (pid, statusp, options)
63#else
64#  define WAITPID(pid, statusp, options) wait (statusp)
65#endif /* !HAVE_WAITPID */
66
67/* Return the fd from which we are actually getting input. */
68#define input_tty() (shell_tty != -1) ? shell_tty : fileno (stderr)
69
70#if !defined (errno)
71extern int errno;
72#endif /* !errno */
73
74extern int interactive, interactive_shell, login_shell;
75extern int subshell_environment;
76extern int last_command_exit_value, last_command_exit_signal;
77extern int interrupt_immediately;
78extern sh_builtin_func_t *this_shell_builtin;
79#if defined (HAVE_POSIX_SIGNALS)
80extern sigset_t top_level_mask;
81#endif
82extern procenv_t wait_intr_buf;
83extern int wait_signal_received;
84
85pid_t last_made_pid = NO_PID;
86pid_t last_asynchronous_pid = NO_PID;
87
88/* Call this when you start making children. */
89int already_making_children = 0;
90
91/* The controlling tty for this shell. */
92int shell_tty = -1;
93
94/* If this is non-zero, $LINES and $COLUMNS are reset after every process
95   exits from get_tty_state(). */
96int check_window_size;
97
98/* STATUS and FLAGS are only valid if pid != NO_PID
99   STATUS is only valid if (flags & PROC_RUNNING) == 0 */
100struct proc_status {
101  pid_t pid;
102  int status;	/* Exit status of PID or 128 + fatal signal number */
103  int flags;
104};
105
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
111
112/* Return values from find_status_by_pid */
113#define PROC_BAD	 -1
114#define PROC_STILL_ALIVE -2
115
116static struct proc_status *pid_list = (struct proc_status *)NULL;
117static int pid_list_size;
118static int wait_sigint_received;
119
120static long child_max = -1L;
121
122static void alloc_pid_list __P((void));
123static int find_proc_slot __P((void));
124static int find_index_by_pid __P((pid_t));
125static int find_status_by_pid __P((pid_t));
126static int process_exit_status __P((WAIT));
127static int find_termsig_by_pid __P((pid_t));
128static int get_termsig __P((WAIT));
129static void set_pid_status __P((pid_t, WAIT));
130static void set_pid_flags __P((pid_t, int));
131static void unset_pid_flags __P((pid_t, int));
132static int get_pid_flags __P((pid_t));
133static void add_pid __P((pid_t, int));
134static void mark_dead_jobs_as_notified __P((int));
135
136static sighandler wait_sigint_handler __P((int));
137static char *j_strsignal __P((int));
138
139#if defined (HAVE_WAITPID)
140static void reap_zombie_children __P((void));
141#endif
142
143#if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS)
144static int siginterrupt __P((int, int));
145#endif
146
147static void restore_sigint_handler __P((void));
148
149/* Allocate new, or grow existing PID_LIST. */
150static void
151alloc_pid_list ()
152{
153  register int i;
154  int old = pid_list_size;
155
156  pid_list_size += 10;
157  pid_list = (struct proc_status *)xrealloc (pid_list, pid_list_size * sizeof (struct proc_status));
158
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;
162}
163
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. */
166static int
167find_proc_slot ()
168{
169  register int i;
170
171  for (i = 0; i < pid_list_size; i++)
172    if (pid_list[i].pid == NO_PID)
173      return (i);
174
175  if (i == pid_list_size)
176    alloc_pid_list ();
177
178  return (i);
179}
180
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. */
183static int
184find_index_by_pid (pid)
185     pid_t pid;
186{
187  register int i;
188
189  for (i = 0; i < pid_list_size; i++)
190    if (pid_list[i].pid == pid)
191      return (i);
192
193  return (NO_PID);
194}
195
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. */
198static int
199find_status_by_pid (pid)
200     pid_t pid;
201{
202  int i;
203
204  i = find_index_by_pid (pid);
205  if (i == NO_PID)
206    return (PROC_BAD);
207  if (pid_list[i].flags & PROC_RUNNING)
208    return (PROC_STILL_ALIVE);
209  return (pid_list[i].status);
210}
211
212static int
213process_exit_status (status)
214     WAIT status;
215{
216  if (WIFSIGNALED (status))
217    return (128 + WTERMSIG (status));
218  else
219    return (WEXITSTATUS (status));
220}
221
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. */
224static int
225find_termsig_by_pid (pid)
226     pid_t pid;
227{
228  int i;
229
230  i = find_index_by_pid (pid);
231  if (i == NO_PID)
232    return (0);
233  if (pid_list[i].flags & PROC_RUNNING)
234    return (0);
235  return (get_termsig (pid_list[i].status));
236}
237
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. */
241static int
242get_termsig (status)
243     WAIT status;
244{
245  if (WIFSTOPPED (status) == 0 && WIFSIGNALED (status))
246    return (WTERMSIG (status));
247  else
248    return (0);
249}
250
251/* Give PID the status value STATUS in the PID_LIST array. */
252static void
253set_pid_status (pid, status)
254     pid_t pid;
255     WAIT status;
256{
257  int slot;
258
259  slot = find_index_by_pid (pid);
260  if (slot == NO_PID)
261    return;
262
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
268     cleaned up. */
269  if ((pid_list[slot].flags & PROC_ASYNC) == 0)
270    pid_list[slot].flags |= PROC_NOTIFIED;
271}
272
273/* Give PID the flags FLAGS in the PID_LIST array. */
274static void
275set_pid_flags (pid, flags)
276     pid_t pid;
277     int flags;
278{
279  int slot;
280
281  slot = find_index_by_pid (pid);
282  if (slot == NO_PID)
283    return;
284
285  pid_list[slot].flags |= flags;
286}
287
288/* Unset FLAGS for PID in the pid list */
289static void
290unset_pid_flags (pid, flags)
291     pid_t pid;
292     int flags;
293{
294  int slot;
295
296  slot = find_index_by_pid (pid);
297  if (slot == NO_PID)
298    return;
299
300  pid_list[slot].flags &= ~flags;
301}
302
303/* Return the flags corresponding to PID in the PID_LIST array. */
304static int
305get_pid_flags (pid)
306     pid_t pid;
307{
308  int slot;
309
310  slot = find_index_by_pid (pid);
311  if (slot == NO_PID)
312    return 0;
313
314  return (pid_list[slot].flags);
315}
316
317static void
318add_pid (pid, async)
319     pid_t pid;
320     int async;
321{
322  int slot;
323
324  slot = find_proc_slot ();
325
326  pid_list[slot].pid = pid;
327  pid_list[slot].status = -1;
328  pid_list[slot].flags = PROC_RUNNING;
329  if (async)
330    pid_list[slot].flags |= PROC_ASYNC;
331}
332
333static void
334mark_dead_jobs_as_notified (force)
335     int force;
336{
337  register int i, ndead;
338
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++)
341    {
342      if (pid_list[i].pid == NO_PID)
343	continue;
344      if (((pid_list[i].flags & PROC_RUNNING) == 0) &&
345	   (pid_list[i].flags & PROC_ASYNC))
346	ndead++;
347    }
348
349  if (child_max < 0)
350    child_max = getmaxchild ();
351  if (child_max < 0)
352    child_max = DEFAULT_CHILD_MAX;
353
354  if (force == 0 && ndead <= child_max)
355    return;
356
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++)
360    {
361      if (pid_list[i].pid == NO_PID)
362	continue;
363      if (((pid_list[i].flags & PROC_RUNNING) == 0) &&
364	   pid_list[i].pid != last_asynchronous_pid)
365	{
366	  pid_list[i].flags |= PROC_NOTIFIED;
367	  if (force == 0 && (pid_list[i].flags & PROC_ASYNC) && --ndead <= child_max)
368	    break;
369	}
370    }
371}
372
373/* Remove all dead, notified jobs from the pid_list. */
374int
375cleanup_dead_jobs ()
376{
377  register int i;
378
379#if defined (HAVE_WAITPID)
380  reap_zombie_children ();
381#endif
382
383  for (i = 0; i < pid_list_size; i++)
384    {
385      if ((pid_list[i].flags & PROC_RUNNING) == 0 &&
386	  (pid_list[i].flags & PROC_NOTIFIED))
387	pid_list[i].pid = NO_PID;
388    }
389
390  return 0;
391}
392
393void
394reap_dead_jobs ()
395{
396  mark_dead_jobs_as_notified (0);
397  cleanup_dead_jobs ();
398}
399
400/* Initialize the job control mechanism, and set up the tty stuff. */
401initialize_job_control (force)
402     int force;
403{
404  shell_tty = fileno (stderr);
405
406  if (interactive)
407    get_tty_state ();
408}
409
410/* Setup this shell to handle C-C, etc. */
411void
412initialize_job_signals ()
413{
414  set_signal_handler (SIGINT, sigint_sighandler);
415
416  /* If this is a login shell we don't wish to be disturbed by
417     stop signals. */
418  if (login_shell)
419    ignore_tty_job_signals ();
420}
421
422#if defined (HAVE_WAITPID)
423/* Collect the status of all zombie children so that their system
424   resources can be deallocated. */
425static void
426reap_zombie_children ()
427{
428#  if defined (WNOHANG)
429  pid_t pid;
430  WAIT status;
431
432  CHECK_TERMSIG;
433  while ((pid = waitpid (-1, (int *)&status, WNOHANG)) > 0)
434    set_pid_status (pid, status);
435#  endif /* WNOHANG */
436  CHECK_TERMSIG;
437}
438#endif /* WAITPID */
439
440#if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS)
441static int
442siginterrupt (sig, flag)
443     int sig, flag;
444{
445  struct sigaction act;
446
447  sigaction (sig, (struct sigaction *)NULL, &act);
448
449  if (flag)
450    act.sa_flags &= ~SA_RESTART;
451  else
452    act.sa_flags |= SA_RESTART;
453
454  return (sigaction (sig, &act, (struct sigaction *)NULL));
455}
456#endif /* !HAVE_SIGINTERRUPT && HAVE_POSIX_SIGNALS */
457
458/* Fork, handling errors.  Returns the pid of the newly made child, or 0.
459   COMMAND is just for remembering the name of the command; we don't do
460   anything else with it.  ASYNC_P says what to do with the tty.  If
461   non-zero, then don't give it away. */
462pid_t
463make_child (command, async_p)
464     char *command;
465     int async_p;
466{
467  pid_t pid;
468#if defined (HAVE_WAITPID)
469  int retry = 1;
470#endif /* HAVE_WAITPID */
471
472  /* Discard saved memory. */
473  if (command)
474    free (command);
475
476  start_pipeline ();
477
478#if defined (BUFFERED_INPUT)
479  /* If default_buffered_input is active, we are reading a script.  If
480     the command is asynchronous, we have already duplicated /dev/null
481     as fd 0, but have not changed the buffered stream corresponding to
482     the old fd 0.  We don't want to sync the stream in this case. */
483  if (default_buffered_input != -1 && (!async_p || default_buffered_input > 0))
484    sync_buffered_stream (default_buffered_input);
485#endif /* BUFFERED_INPUT */
486
487  /* Create the child, handle severe errors. */
488#if defined (HAVE_WAITPID)
489  retry_fork:
490#endif /* HAVE_WAITPID */
491
492  if ((pid = fork ()) < 0)
493    {
494#if defined (HAVE_WAITPID)
495      /* Posix systems with a non-blocking waitpid () system call available
496	 get another chance after zombies are reaped. */
497      if (errno == EAGAIN && retry)
498	{
499	  reap_zombie_children ();
500	  retry = 0;
501	  goto retry_fork;
502	}
503#endif /* HAVE_WAITPID */
504
505      sys_error ("fork");
506
507      throw_to_top_level ();
508    }
509
510  if (pid == 0)
511    {
512#if defined (BUFFERED_INPUT)
513      unset_bash_input (0);
514#endif /* BUFFERED_INPUT */
515
516#if defined (HAVE_POSIX_SIGNALS)
517      /* Restore top-level signal mask. */
518      sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL);
519#endif
520
521      /* Ignore INT and QUIT in asynchronous children. */
522      if (async_p)
523	last_asynchronous_pid = getpid ();
524
525      default_tty_job_signals ();
526    }
527  else
528    {
529      /* In the parent. */
530
531      last_made_pid = pid;
532
533      if (async_p)
534	last_asynchronous_pid = pid;
535
536      add_pid (pid, async_p);
537    }
538  return (pid);
539}
540
541void
542ignore_tty_job_signals ()
543{
544#if defined (SIGTSTP)
545  set_signal_handler (SIGTSTP, SIG_IGN);
546  set_signal_handler (SIGTTIN, SIG_IGN);
547  set_signal_handler (SIGTTOU, SIG_IGN);
548#endif
549}
550
551void
552default_tty_job_signals ()
553{
554#if defined (SIGTSTP)
555  set_signal_handler (SIGTSTP, SIG_DFL);
556  set_signal_handler (SIGTTIN, SIG_DFL);
557  set_signal_handler (SIGTTOU, SIG_DFL);
558#endif
559}
560
561/* Wait for a single pid (PID) and return its exit status.  Called by
562   the wait builtin. */
563int
564wait_for_single_pid (pid)
565     pid_t pid;
566{
567  pid_t got_pid;
568  WAIT status;
569  int pstatus, flags;
570
571  pstatus = find_status_by_pid (pid);
572
573  if (pstatus == PROC_BAD)
574    {
575      internal_error (_("wait: pid %ld is not a child of this shell"), (long)pid);
576      return (127);
577    }
578
579  if (pstatus != PROC_STILL_ALIVE)
580    {
581      if (pstatus > 128)
582	last_command_exit_signal = find_termsig_by_pid (pid);
583      return (pstatus);
584    }
585
586  siginterrupt (SIGINT, 1);
587  while ((got_pid = WAITPID (pid, &status, 0)) != pid)
588    {
589      CHECK_TERMSIG;
590      if (got_pid < 0)
591	{
592	  if (errno != EINTR && errno != ECHILD)
593	    {
594	      siginterrupt (SIGINT, 0);
595	      sys_error ("wait");
596	    }
597	  break;
598	}
599      else if (got_pid > 0)
600	set_pid_status (got_pid, status);
601    }
602
603  if (got_pid > 0)
604    {
605      set_pid_status (got_pid, status);
606      set_pid_flags (got_pid, PROC_NOTIFIED);
607    }
608
609  siginterrupt (SIGINT, 0);
610  QUIT;
611
612  return (got_pid > 0 ? process_exit_status (status) : -1);
613}
614
615/* Wait for all of the shell's children to exit.  Called by the `wait'
616   builtin. */
617void
618wait_for_background_pids ()
619{
620  pid_t got_pid;
621  WAIT status;
622
623  /* If we aren't using job control, we let the kernel take care of the
624     bookkeeping for us.  wait () will return -1 and set errno to ECHILD
625     when there are no more unwaited-for child processes on both
626     4.2 BSD-based and System V-based systems. */
627
628  siginterrupt (SIGINT, 1);
629
630  /* Wait for ECHILD */
631  while ((got_pid = WAITPID (-1, &status, 0)) != -1)
632    set_pid_status (got_pid, status);
633
634  if (errno != EINTR && errno != ECHILD)
635    {
636      siginterrupt (SIGINT, 0);
637      sys_error("wait");
638    }
639
640  siginterrupt (SIGINT, 0);
641  QUIT;
642
643  mark_dead_jobs_as_notified (1);
644  cleanup_dead_jobs ();
645}
646
647/* Make OLD_SIGINT_HANDLER the SIGINT signal handler. */
648#define INVALID_SIGNAL_HANDLER (SigHandler *)wait_for_background_pids
649static SigHandler *old_sigint_handler = INVALID_SIGNAL_HANDLER;
650
651static void
652restore_sigint_handler ()
653{
654  if (old_sigint_handler != INVALID_SIGNAL_HANDLER)
655    {
656      set_signal_handler (SIGINT, old_sigint_handler);
657      old_sigint_handler = INVALID_SIGNAL_HANDLER;
658    }
659}
660
661/* Handle SIGINT while we are waiting for children in a script to exit.
662   All interrupts are effectively ignored by the shell, but allowed to
663   kill a running job. */
664static sighandler
665wait_sigint_handler (sig)
666     int sig;
667{
668  SigHandler *sigint_handler;
669
670  /* If we got a SIGINT while in `wait', and SIGINT is trapped, do
671     what POSIX.2 says (see builtins/wait.def for more info). */
672  if (this_shell_builtin && this_shell_builtin == wait_builtin &&
673      signal_is_trapped (SIGINT) &&
674      ((sigint_handler = trap_to_sighandler (SIGINT)) == trap_handler))
675    {
676      last_command_exit_value = EXECUTION_FAILURE;
677      restore_sigint_handler ();
678      interrupt_immediately = 0;
679      trap_handler (SIGINT);	/* set pending_traps[SIGINT] */
680      wait_signal_received = SIGINT;
681      longjmp (wait_intr_buf, 1);
682    }
683
684  if (interrupt_immediately)
685    {
686      last_command_exit_value = EXECUTION_FAILURE;
687      restore_sigint_handler ();
688      ADDINTERRUPT;
689      QUIT;
690    }
691
692  wait_sigint_received = 1;
693
694  SIGRETURN (0);
695}
696
697static char *
698j_strsignal (s)
699     int s;
700{
701  static char retcode_name_buffer[64] = { '\0' };
702  char *x;
703
704  x = strsignal (s);
705  if (x == 0)
706    {
707      x = retcode_name_buffer;
708      sprintf (x, "Signal %d", s);
709    }
710  return x;
711}
712
713/* Wait for pid (one of our children) to terminate.  This is called only
714   by the execution code in execute_cmd.c. */
715int
716wait_for (pid)
717     pid_t pid;
718{
719  int return_val, pstatus;
720  pid_t got_pid;
721  WAIT status;
722
723  pstatus = find_status_by_pid (pid);
724
725  if (pstatus == PROC_BAD)
726    return (0);
727
728  if (pstatus != PROC_STILL_ALIVE)
729    {
730      if (pstatus > 128)
731	last_command_exit_signal = find_termsig_by_pid (pid);
732      return (pstatus);
733    }
734
735  /* If we are running a script, ignore SIGINT while we're waiting for
736     a child to exit.  The loop below does some of this, but not all. */
737  wait_sigint_received = 0;
738  if (interactive_shell == 0)
739    old_sigint_handler = set_signal_handler (SIGINT, wait_sigint_handler);
740
741  while ((got_pid = WAITPID (-1, &status, 0)) != pid) /* XXX was pid now -1 */
742    {
743      CHECK_TERMSIG;
744      if (got_pid < 0 && errno == ECHILD)
745	{
746#if !defined (_POSIX_VERSION)
747	  status.w_termsig = status.w_retcode = 0;
748#else
749	  status = 0;
750#endif /* _POSIX_VERSION */
751	  break;
752	}
753      else if (got_pid < 0 && errno != EINTR)
754	programming_error ("wait_for(%ld): %s", (long)pid, strerror(errno));
755      else if (got_pid > 0)
756	set_pid_status (got_pid, status);
757    }
758
759  if (got_pid > 0)
760    set_pid_status (got_pid, status);
761
762#if defined (HAVE_WAITPID)
763  if (got_pid >= 0)
764    reap_zombie_children ();
765#endif /* HAVE_WAITPID */
766
767  if (interactive_shell == 0)
768    {
769      SigHandler *temp_handler;
770
771      temp_handler = old_sigint_handler;
772      restore_sigint_handler ();
773
774      /* If the job exited because of SIGINT, make sure the shell acts as if
775	 it had received one also. */
776      if (WIFSIGNALED (status) && (WTERMSIG (status) == SIGINT))
777	{
778
779	  if (maybe_call_trap_handler (SIGINT) == 0)
780	    {
781	      if (temp_handler == SIG_DFL)
782		termsig_handler (SIGINT);
783	      else if (temp_handler != INVALID_SIGNAL_HANDLER && temp_handler != SIG_IGN)
784		(*temp_handler) (SIGINT);
785	    }
786	}
787    }
788
789  /* Default return value. */
790  /* ``a full 8 bits of status is returned'' */
791  return_val = process_exit_status (status);
792  last_command_exit_signal = get_termsig (status);
793
794#if !defined (DONT_REPORT_SIGPIPE)
795  if ((WIFSTOPPED (status) == 0) && WIFSIGNALED (status) &&
796	(WTERMSIG (status) != SIGINT))
797#else
798  if ((WIFSTOPPED (status) == 0) && WIFSIGNALED (status) &&
799	(WTERMSIG (status) != SIGINT) && (WTERMSIG (status) != SIGPIPE))
800#endif
801    {
802      fprintf (stderr, "%s", j_strsignal (WTERMSIG (status)));
803      if (WIFCORED (status))
804	fprintf (stderr, " (core dumped)");
805      fprintf (stderr, "\n");
806    }
807
808  if (interactive_shell && subshell_environment == 0)
809    {
810      if (WIFSIGNALED (status) || WIFSTOPPED (status))
811	set_tty_state ();
812      else
813	get_tty_state ();
814    }
815
816  return (return_val);
817}
818
819/* Send PID SIGNAL.  Returns -1 on failure, 0 on success.  If GROUP is non-zero,
820   or PID is less than -1, then kill the process group associated with PID. */
821int
822kill_pid (pid, signal, group)
823     pid_t pid;
824     int signal, group;
825{
826  int result;
827
828  if (pid < -1)
829    {
830      pid = -pid;
831      group = 1;
832    }
833  result = group ? killpg (pid, signal) : kill (pid, signal);
834  return (result);
835}
836
837static TTYSTRUCT shell_tty_info;
838static int got_tty_state;
839
840/* Fill the contents of shell_tty_info with the current tty info. */
841get_tty_state ()
842{
843  int tty;
844
845  tty = input_tty ();
846  if (tty != -1)
847    {
848      ttgetattr (tty, &shell_tty_info);
849      got_tty_state = 1;
850      if (check_window_size)
851	get_new_window_size (0, (int *)0, (int *)0);
852    }
853}
854
855/* Make the current tty use the state in shell_tty_info. */
856int
857set_tty_state ()
858{
859  int tty;
860
861  tty = input_tty ();
862  if (tty != -1)
863    {
864      if (got_tty_state == 0)
865	return 0;
866      ttsetattr (tty, &shell_tty_info);
867    }
868  return 0;
869}
870
871/* Give the terminal to PGRP.  */
872give_terminal_to (pgrp, force)
873     pid_t pgrp;
874     int force;
875{
876}
877
878/* Stop a pipeline. */
879int
880stop_pipeline (async, ignore)
881     int async;
882     COMMAND *ignore;
883{
884  already_making_children = 0;
885  return 0;
886}
887
888void
889start_pipeline ()
890{
891  already_making_children = 1;
892}
893
894void
895stop_making_children ()
896{
897  already_making_children = 0;
898}
899
900int
901get_job_by_pid (pid, block)
902     pid_t pid;
903     int block;
904{
905  int i;
906
907  i = find_index_by_pid (pid);
908  return ((i == NO_PID) ? PROC_BAD : i);
909}
910
911/* Print descriptive information about the job with leader pid PID. */
912void
913describe_pid (pid)
914     pid_t pid;
915{
916  fprintf (stderr, "%ld\n", (long) pid);
917}
918
919void
920unfreeze_jobs_list ()
921{
922}
923
924int
925count_all_jobs ()
926{
927  return 0;
928}
929