This file is wait.def, from which is created wait.c.
It implements the builtin "wait" in Bash.

Copyright (C) 1987-2005 Free Software Foundation, Inc.

This file is part of GNU Bash, the Bourne Again SHell.

Bash is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.

Bash is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License along
with Bash; see the file COPYING.  If not, write to the Free Software
Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA.

$BUILTIN wait
$FUNCTION wait_builtin
$DEPENDS_ON JOB_CONTROL
$PRODUCES wait.c
$SHORT_DOC wait [n]
Wait for the specified process and report its termination status.  If
N is not given, all currently active child processes are waited for,
and the return code is zero.  N may be a process ID or a job
specification; if a job spec is given, all processes in the job's
pipeline are waited for.
$END

$BUILTIN wait
$FUNCTION wait_builtin
$DEPENDS_ON !JOB_CONTROL
$SHORT_DOC wait [n]
Wait for the specified process and report its termination status.  If
N is not given, all currently active child processes are waited for,
and the return code is zero.  N is a process ID; if it is not given,
all child processes of the shell are waited for.
$END

#include <config.h>

#include "../bashtypes.h"
#include <signal.h>

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif

#include <chartypes.h>

#include "../bashansi.h"

#include "../shell.h"
#include "../jobs.h"
#include "common.h"
#include "bashgetopt.h"

extern int wait_signal_received;

procenv_t wait_intr_buf;

/* Wait for the pid in LIST to stop or die.  If no arguments are given, then
   wait for all of the active background processes of the shell and return
   0.  If a list of pids or job specs are given, return the exit status of
   the last one waited for. */

#define WAIT_RETURN(s) \
  do \
    { \
      interrupt_immediately = old_interrupt_immediately;\
      return (s);\
    } \
  while (0)

int
wait_builtin (list)
     WORD_LIST *list;
{
  int status, code;
  volatile int old_interrupt_immediately;

  USE_VAR(list);

  if (no_options (list))
    return (EX_USAGE);
  list = loptend;

  old_interrupt_immediately = interrupt_immediately;
  interrupt_immediately++;

  /* POSIX.2 says:  When the shell is waiting (by means of the wait utility)
     for asynchronous commands to complete, the reception of a signal for
     which a trap has been set shall cause the wait utility to return
     immediately with an exit status greater than 128, after which the trap
     associated with the signal shall be taken.

     We handle SIGINT here; it's the only one that needs to be treated
     specially (I think), since it's handled specially in {no,}jobs.c. */
  code = setjmp (wait_intr_buf);
  if (code)
    {
      status = 128 + wait_signal_received;
      WAIT_RETURN (status);
    }

  /* We support jobs or pids.
     wait <pid-or-job> [pid-or-job ...] */

  /* But wait without any arguments means to wait for all of the shell's
     currently active background processes. */
  if (list == 0)
    {
      wait_for_background_pids ();
      WAIT_RETURN (EXECUTION_SUCCESS);
    }

  status = EXECUTION_SUCCESS;
  while (list)
    {
      pid_t pid;
      char *w;
      intmax_t pid_value;

      w = list->word->word;
      if (DIGIT (*w))
	{
	  if (legal_number (w, &pid_value) && pid_value == (pid_t)pid_value)
	    {
	      pid = (pid_t)pid_value;
	      status = wait_for_single_pid (pid);
	    }
	  else
	    {
	      sh_badpid (w);
	      WAIT_RETURN (EXECUTION_FAILURE);
	    }
	}
#if defined (JOB_CONTROL)
      else if (*w && *w == '%')
	/* Must be a job spec.  Check it out. */
	{
	  int job;
	  sigset_t set, oset;

	  BLOCK_CHILD (set, oset);
	  job = get_job_spec (list);

	  if (INVALID_JOB (job))
	    {
	      if (job != DUP_JOB)
		sh_badjob (list->word->word);
	      UNBLOCK_CHILD (oset);
	      status = 127;	/* As per Posix.2, section 4.70.2 */
	      list = list->next;
	      continue;
	    }

	  /* Job spec used.  Wait for the last pid in the pipeline. */
	  UNBLOCK_CHILD (oset);
	  status = wait_for_job (job);
	}
#endif /* JOB_CONTROL */
      else
	{
	  sh_badpid (w);
	  status = EXECUTION_FAILURE;
	}
      list = list->next;
    }

  WAIT_RETURN (status);
}