Sprite 1984 - 1993/Sprite 1984 - 1993.iso/src/cmds/bash-1.12/dist/jobs.c

C/C++ Source or Header | 1992-01-17 | 53.7 KB | 2,290 lines

/* The thing that makes children, remembers them, and contains wait loops. */

/* This file works with both POSIX and BSD systems. */

/* Copyright (C) 1989 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 1, 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, 675 Mass Ave, Cambridge, MA 02139, USA. */

/* Something that can be ignored. */
#define IGNORE_ARG (char *)0

#include "config.h"

#if !defined (JOB_CONTROL)
#include "nojobs.c"
#else /* JOB_CONTROL */

#include <sys/types.h>
#include "trap.h"
#include <stdio.h>
#include <signal.h>
#include <errno.h>

#if !defined (USG) || defined (HAVE_RESOURCE)
#include <sys/time.h>
#endif /* USG */

#if !defined (_POSIX_VERSION)
#  if defined (HAVE_RESOURCE)
#    include <sys/resource.h>
#  endif
#endif /* _POSIX_VERSION */

#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/param.h>
#include "filecntl.h"

/* Terminal handling stuff, to save and restore tty state. */
#define NEW_TTY_DRIVER

/* Define this if your output is getting swallowed.  It's a no-op on
   machines with the termio or termios tty drivers. */
/* #define DRAIN_OUTPUT */

#if defined (_POSIX_VERSION) && !defined (TERMIOS_MISSING)
#  undef NEW_TTY_DRIVER
#  define TERMIOS_TTY_DRIVER
#  if defined (sun)
#    define _POSIX_SOURCE
#  endif
#else /* !_POSIX_VERSION */
#  if defined (USG) || defined (hpux) || defined (Xenix) || defined (sgi)
#    undef NEW_TTY_DRIVER
#    define TERMIO_TTY_DRIVER
#  endif /* USG | hpux | Xenix | sgi */
#endif /* !_POSIX_VERSION */

/* Include the right header file for the specific type of terminal
   handler installed on this system. */
#if defined (NEW_TTY_DRIVER)
#include <sgtty.h>
#endif

#if defined (TERMIO_TTY_DRIVER)
#include <termio.h>
#endif

#if defined (TERMIOS_TTY_DRIVER)
/* For Sun workstations we undefine a couple of defines so that
   the inclusion of termios.h won't cause complaints. */
#  if defined (sun)
#    undef ECHO
#    undef NOFLSH
#    undef TOSTOP
#  endif /* sun */
#  include <termios.h>
#endif /* TERMIOS_TTY_DRIVER */

/* For the TIOCGPGRP and TIOCSPGRP ioctl parameters on HP-UX */

#if defined (hpux) && !defined (TERMIOS_TTY_DRIVER)
#include <bsdtty.h>
#endif /* hpux && !TERMIOS_TTY_DRIVER */

#include "shell.h"
#include "jobs.h"

/* Not all systems define errno in errno.h. */
extern int errno;
extern int interactive, asynchronous_notification;
extern char *shell_name;
extern char *sys_siglist[];

/* The array of known jobs. */
JOB **jobs = (JOB **)NULL;

/* The number of slots currently allocated to JOBS. */
int job_slots = 0;

/* The number of additional slots to allocate when we run out. */
#define JOB_SLOTS 5

/* The controlling tty for this shell. */
int shell_tty = -1;

/* The shell's process group. */
pid_t shell_pgrp = NO_PID;

/* The terminal's process group. */
pid_t terminal_pgrp = NO_PID;

/* The process group of the shell's parent. */
pid_t original_pgrp = NO_PID;

/* The process group of the pipeline currently being made. */
pid_t pipeline_pgrp = (pid_t)0;

#if defined (PGRP_PIPE)
/* Pipes which each shell uses to communicate with the process group leader
   until all of the processes in a pipeline have been started.  Then the
   process leader is allowed to continue. */
int pgrp_pipe[2] = { -1, -1 };
#endif

/* The job which is current; i.e. the one that `%+' stands for. */
int current_job = NO_JOB;

/* The previous job; i.e. the one that `%-' stands for. */
int previous_job = NO_JOB;

/* Last child made by the shell.  */
pid_t last_made_pid = NO_PID;

/* Pid of the last asynchronous child. */
pid_t last_asynchronous_pid = NO_PID;

/* The pipeline currently being built. */
PROCESS *the_pipeline = (PROCESS *)NULL;

/* If this is non-zero, do job control. */
int job_control = 1;

/* Call this when you start making children. */
int already_making_children = 0;

/* Functions local to this file. */
static sighandler flush_child ();
static PROCESS *find_pipeline ();
static char *job_working_directory ();
static pid_t last_pid ();
static int set_new_line_discipline (), map_over_jobs (), last_running_job ();
static int most_recent_job_in_state (), last_stopped_job (), find_job ();
static void notify_of_job_status (), cleanup_dead_jobs (), discard_pipeline ();
static void add_process (), set_current_job (), reset_current ();
static void pretty_print_job ();
#if defined (PGRP_PIPE)
static void pipe_read (), pipe_close ();
#endif

#if !defined (_POSIX_VERSION)

/* These are definitions to map POSIX 1003.1 functions onto existing BSD
   library functions and system calls. */
#define setpgid(pid, pgrp)    setpgrp (pid, pgrp)
#define tcsetpgrp(fd, pgrp)    ioctl ((fd), TIOCSPGRP, &(pgrp))

pid_t
tcgetpgrp (fd)
     int fd;
{
  pid_t pgrp;

  /* ioctl will handle setting errno correctly. */
  if (ioctl (fd, TIOCGPGRP, &pgrp) < 0)
    return (-1);
  return (pgrp);
}

/* Perform OPERATION on NEWSET, perhaps leaving information in OLDSET. */
sigprocmask (operation, newset, oldset)
     int operation, *newset, *oldset;
{
  switch (operation)
    {
    case SIG_BLOCK:
      *oldset = sigblock (*newset);
      break;

    case SIG_SETMASK:
      sigsetmask (*newset);
      break;

    default:
      report_error ("Bad code in jobs.c: sigprocmask");
    }
}
#endif /* !_POSIX_VERSION */

/* Return the working directory for the current process. */
static char *
job_working_directory ()
{
  extern char *get_working_directory ();
  char *dir;

  dir = get_string_value ("PWD");
  if (dir)
    return (savestring (dir));

  dir = get_working_directory ("");
  if (dir)
    return (dir);

  return (savestring ("<unknown>"));
}

making_children ()
{
  if (already_making_children)
    return;

  already_making_children = 1;
  start_pipeline ();
}

stop_making_children ()
{
  already_making_children = 0;
}

/* Start building a pipeline.  */
start_pipeline ()
{
  if (the_pipeline)
    {
      discard_pipeline (the_pipeline);
      the_pipeline = (PROCESS *)NULL;
      pipeline_pgrp = 0;
#if defined (PGRP_PIPE)
      pipe_close (pgrp_pipe);
#endif
    }

#if defined (PGRP_PIPE)
  if (job_control)
    {
      if (pipe (pgrp_pipe) == -1)
    report_error ("start_pipeline: pgrp pipe");
    }
#endif
}

/* Stop building a pipeline.  Install the process list in the job array.
   This returns the index of the newly installed job.
   DEFERRED is a command structure to be executed upon satisfactory
   execution exit of this pipeline. */
int
stop_pipeline (async, deferred)
     int async;
     COMMAND *deferred;
{
  register int i, j;
  JOB *newjob = (JOB *)NULL;
  char *get_string_value ();
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);

#if defined (PGRP_PIPE)
  /* The parent closes the process group synchronization pipe. */
  pipe_close (pgrp_pipe);
#endif

  cleanup_dead_jobs ();

  if (!job_slots)
    {
      jobs =
    (JOB **)xmalloc ((job_slots = JOB_SLOTS) * sizeof (JOB *));

      /* Now blank out these new entries. */
      for (i = 0; i < job_slots; i++)
    jobs[i] = (JOB *)NULL;
    }

  /* Scan from the last slot backward, looking for the next free one. */
  for (i = job_slots; i; i--)
    if (jobs[i - 1])
      break;

  /* Do we need more room? */
  if (i == job_slots)
    {
      jobs = (JOB **)realloc
    (jobs, (1 + (job_slots += JOB_SLOTS)) * sizeof (JOB *));

      for (j = i; j < job_slots; j++)
    jobs[j] = (JOB *)NULL;
    }

  /* Add the current pipeline to the job list. */
  if (the_pipeline)
    {
      register PROCESS *p;

      newjob = (JOB *)xmalloc (sizeof (JOB));

      for (p = the_pipeline; p->next != the_pipeline; p = p->next);
      p->next = (PROCESS *)NULL;
      newjob->pipe = (PROCESS *)reverse_list (the_pipeline);
      for (p = newjob->pipe; p->next; p = p->next);
      p->next = newjob->pipe;

      the_pipeline = (PROCESS *)NULL;
      newjob->pgrp = pipeline_pgrp;
      pipeline_pgrp = 0;

      /* Flag to see if in another pgrp. */
      newjob->job_control = job_control;

      /* Set the state of this pipeline. */
      {
    register PROCESS *p = newjob->pipe;
    register int any_alive = 0;
    register int any_stopped = 0;

    do
      {
        any_alive |= p->running;
        any_stopped |= WIFSTOPPED (p->status);
        p = p->next;
      }
    while (p != newjob->pipe);

    if (any_alive)
      {
        newjob->state = JRUNNING;
      }
    else
      {
        if (any_stopped)
          newjob->state = JSTOPPED;
        else
          newjob->state = JDEAD;
      }
      }

      newjob->notified = 0;
      newjob->wd = job_working_directory ();
      newjob->deferred = deferred;

      jobs[i] = newjob;
    }

  if (async)
    {
      if (newjob)
    newjob->foreground = 0;
      reset_current ();
    }
  else
    {
      if (newjob)
    {
      newjob->foreground = 1;
      /*
       *        !!!!! NOTE !!!!!  ([e-mail])
       *
       * The currently-accepted job control wisdom says to set the
       * terminal's process group n+1 times in an n-step pipeline:
       * once in the parent and once in each child.  This is where
       * the parent gives it away.
       *
       */
      if (job_control && newjob->pgrp)
        give_terminal_to (newjob->pgrp);
    }
    }

  stop_making_children ();
  UNBLOCK_CHILD (oset);
  return (current_job);
}

/* Delete all DEAD jobs that the user had received notification about. */
static void
cleanup_dead_jobs ()
{
  register int i;
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);

  for (i = 0; i < job_slots; i++)
    if (jobs[i] && JOBSTATE (i) == JDEAD && jobs[i]->notified)
      delete_job (i);

  UNBLOCK_CHILD (oset);
}

/* Delete the job at INDEX from the job list. */
delete_job (index)
     int index;
{
  register JOB *temp = jobs[index];

  if (index == current_job || index == previous_job)
    reset_current ();

  jobs[index] = (JOB *)NULL;

  free (temp->wd);
  discard_pipeline (temp->pipe);

  if (temp->deferred)
    dispose_command (temp->deferred);

  free (temp);
}

/* Get rid of the data structure associated with a process chain. */
static void
discard_pipeline (chain)
     register PROCESS *chain;
{
  register PROCESS *this, *next;

  this = chain;
  do
    {
      next = this->next;
      if (this->command)
    free (this->command);
      free (this);
      this = next;
    }
  while (this != chain);
}

/* Add this process to the chain being built in the_pipeline.
   NAME is the command string that will be exec'ed later.
   PID is the process id of the child. */
static void
add_process (name, pid)
     char *name;
     pid_t pid;
{
  PROCESS *t = (PROCESS *)xmalloc (sizeof (PROCESS));

  t->next = the_pipeline;
  t->pid = pid;
  WSTATUS (t->status) = 0;
  t->running = 1;
  t->command = name;
  the_pipeline = t;

  if (!(t->next))
    t->next = t;
  else
    {
      register PROCESS *p = t->next;

      while (p->next != t->next) p = p->next;
      p->next = t;
    }
}

/* Map FUNC over the list of jobs.  If FUNC returns non-zero,
   then it is time to stop mapping, and that is the return value
   for map_over_jobs.  FUNC is called with a JOB, arg1, arg2,
   and INDEX. */
static int
map_over_jobs (func, arg1, arg2)
     Function *func;
{
  register int i;

  for (i = 0; i < job_slots; i++)
    {
      if (jobs[i])
    {
      int result = (*func)(jobs[i], arg1, arg2, i);
      if (result)
        return (result);
    }
    }
  return (0);
}

/* Cause all the jobs in the current pipeline to exit. */
terminate_current_pipeline ()
{
  if (pipeline_pgrp && pipeline_pgrp != shell_pgrp)
    {
      killpg (pipeline_pgrp, SIGTERM);
      killpg (pipeline_pgrp, SIGCONT);
    }
}

/* Cause all stopped jobs to exit. */
void
terminate_stopped_jobs ()
{
  register int i;

  for (i = 0; i < job_slots; i++)
    {
      if (jobs[i] && (JOBSTATE (i) == JSTOPPED))
    {
      killpg (jobs[i]->pgrp, SIGTERM);
      killpg (jobs[i]->pgrp, SIGCONT);
    }
    }
}

/* Cause all jobs, running or stopped, to receive a hangup signal. */
void
hangup_all_jobs ()
{
  register int i;

  for (i = 0; i < job_slots; i++)
    {
      if (jobs[i])
    {
      killpg (jobs[i]->pgrp, SIGHUP);
      if (JOBSTATE (i) == JSTOPPED)
        killpg (jobs[i]->pgrp, SIGCONT);
    }
    }
}

kill_current_pipeline ()
{
  stop_making_children ();
  start_pipeline ();
}

/* Return the pipeline that PID belongs to.  Note that the pipeline
   doesn't have to belong to a job. */
static PROCESS *
find_pipeline (pid)
     pid_t pid;
{
  int job;

  /* See if this process is in the pipeline that we are building. */
  if (the_pipeline)
    {
      register PROCESS *p = the_pipeline;

      do
    {
      /* Return it if we found it. */
      if (p->pid == pid)
        return (p);

      p = p->next;
    }
      while (p != the_pipeline);
    }

  job = find_job (pid);

  if (job == NO_JOB)
    return ((PROCESS *)NULL);
  else
    return (jobs[job]->pipe);
}

/* Return the job index that PID belongs to, or NO_JOB if it doesn't
   belong to any job. */
static int
find_job (pid)
     pid_t pid;
{
  register int i;
  register PROCESS *p;

  for (i = 0; i < job_slots; i++)
    {
      if (jobs[i])
    {
      p = jobs[i]->pipe;

      do
        {
          if (p->pid == pid)
        return (i);

          p = p->next;
        }
      while (p != jobs[i]->pipe);
    }
    }

  return (NO_JOB);
}

/* Print descriptive information about the job with leader pid PID. */
describe_pid (pid)
     pid_t pid;
{
  int job;
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);

  job = find_job (pid);

  if (job != NO_JOB)
    printf ("[%d] %d\n", job + 1, pid);
  else
    programming_error ("describe_pid: No such pid (%d)!\n", pid);

  UNBLOCK_CHILD (oset);
}

/* This is the way to print out information on a job if you
   know the index.  FORMAT is:

    JLIST_NORMAL)   [1]+ Running       emacs
    JLIST_LONG  )   [1]+ 2378 Running      emacs
    -1      )   [1]+ 2378          emacs

    JLIST_NORMAL)   [1]+ Stopped       ls | more
    JLIST_LONG  )   [1]+ 2369 Stopped      ls
             2367        | more
    JLIST_PID_ONLY)
    Just list the pid of the process group leader (really
    the process group).
    JLIST_CHANGED_ONLY)
    Use format JLIST_NORMAL, but list only jobs about which
    the user has not been notified. */
static void
pretty_print_job (index, format, stream)
     int index, format;
     FILE *stream;
{
  register PROCESS *p, *first, *last;
  int name_padding;
  char retcode_name_buffer[20];
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);

  /* Format only pid information about the process group leader? */
  if (format == JLIST_PID_ONLY)
    {
      fprintf (stream, "%d\n", jobs[index]->pipe->pid);
      UNBLOCK_CHILD (oset);
      return;
    }

  if (format == JLIST_CHANGED_ONLY)
    {
      if (jobs[index]->notified == 1)
    {
      UNBLOCK_CHILD (oset);
      return;
    }
      format = JLIST_STANDARD;
    }

  fprintf (stream, "[%d]%c ", index + 1,
       (index == current_job) ? '+':
       (index == previous_job) ? '-' : ' ');

  first = last = p = jobs[index]->pipe;
  while (last->next != first)
    last = last->next;

  /* We have printed information about this job.  When the job's
     status changes, flush_child () sets the notification flag to 0. */
  jobs[index]->notified = 1;

  for (;;)
    {
      if (p != first)
    fprintf (stream, format ? "     " : " |");

      if (format)
    fprintf (stream, "%d", p->pid);

      fprintf (stream, " ");

      if (format > -1)
    {
      PROCESS *show = format ? p : last;
      char *temp = "Done";

      if (JOBSTATE (index) == JSTOPPED && !format)
        temp = "Stopped";

      if (JOBSTATE (index) == JRUNNING)
        temp = "Running";
      else
        {
        if (WIFSTOPPED (show->status))
          temp = sys_siglist[WSTOPSIG (show->status)];
        else if (WIFSIGNALED (show->status))
          temp = sys_siglist[WTERMSIG (show->status)];
        else if (WIFEXITED (show->status))
          {
            temp = retcode_name_buffer;
            sprintf (temp, "Exit %d", WEXITSTATUS (show->status));
          }
        else
          temp = "Unknown status";
        }

      if (p != first)
        {
          if (format)
        {
          if (show->running == first->running &&
              WSTATUS (show->status) == WSTATUS (first->status))
            temp = "";
        }
          else
        temp = (char *)NULL;
        }

      if (temp)
        {
          fprintf (stream, "%s", temp);

          if (strlen (temp))
        name_padding = LONGEST_SIGNAL_DESC - strlen (temp);
          else
        name_padding = LONGEST_SIGNAL_DESC - 2; /* strlen ("| ") */

          fprintf (stream, "%*s", name_padding, "");

          if ((!WIFSTOPPED (show->status)) && (WIFCORED (show->status)))
        fprintf (stream, "(core dumped) ");
        }
    }

      if (p != first && format)
    fprintf (stream, "| ");

      fprintf (stream, "%s", p->command);

      if (p == last)
    {
      char *wd = job_working_directory ();

      if (JOBSTATE (index) == JRUNNING && jobs[index]->foreground == 0)
        fprintf (stream, " &");

      if (strcmp (wd, jobs[index]->wd) != 0)
        fprintf (stream,
             "  (wd: %s)", polite_directory_format (jobs[index]->wd));
      free (wd);
    }

      if (format || (p == last))
    fprintf (stream, "\r\n");

      if (p == last)
    break;
      p = p->next;
    }

  fflush (stream);
  UNBLOCK_CHILD (oset);
}

int
list_one_job (job, format, ignore, index)
     JOB *job;
     int format, ignore, index;
{
  pretty_print_job (index, format, stdout);
  return (0);
}

/* List jobs.  If FORMAT is non-zero, then the long form of the information
   is printed, else just a short version. */
list_jobs (format)
     int format;
{
  cleanup_dead_jobs ();
  map_over_jobs (list_one_job, format, (int)IGNORE_ARG);
}

/* Fork, handling errors.  Returns the pid of the newly made child, or 0.
   COMMAND is just for remembering the name of the command; we don't do
   anything else with it.  ASYNC_P says what to do with the tty.  If
   non-zero, then don't give it away. */
pid_t
make_child (command, async_p)
     char *command;
     int async_p;
{
  sigset_t set, oset;
  pid_t pid;

  sigemptyset (&set);
  sigaddset (&set, SIGCHLD);
  sigaddset (&set, SIGINT);
  sigemptyset (&oset);
  sigprocmask (SIG_BLOCK, &set, &oset);

  making_children ();

  /* Make new environment array if neccessary. */
  maybe_make_export_env ();

  /* Create the child, handle severe errors. */
  if ((pid = fork ()) < 0)
    {
      report_error ("fork: %s", (char *)strerror (errno));

      /* Kill all of the processes in the current pipeline. */
      terminate_current_pipeline ();

      /* Discard the current pipeline, if any. */
      if (the_pipeline)
    kill_current_pipeline ();

      throw_to_top_level ();    /* Reset signals, etc. */
    }

  if (!pid)
    {
      /* In the child.  Give this child the right process group, set the
     signals to the default state for a new process. */
      extern sigset_t top_level_mask;

      pid_t mine = getpid ();

      /* Cancel traps, in trap.c. */
      restore_original_signals ();

      /* Restore top-level signal mask. */
      sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL);

      if (job_control)
    {
      /* All processes in this pipeline belong in the same
         process group. */

      if (!pipeline_pgrp)    /* Then this is the first child. */
        pipeline_pgrp = mine;

      /* Check for running command in backquotes. */
      if (pipeline_pgrp == shell_pgrp)
        {
          signal (SIGTSTP, SIG_IGN);
          signal (SIGTTOU, SIG_IGN);
          signal (SIGTTIN, SIG_IGN);
        }
      else
        {
          signal (SIGTSTP, SIG_DFL);
          signal (SIGTTOU, SIG_DFL);
          signal (SIGTTIN, SIG_DFL);
        }

      /* Set the process group before trying to mess with the terminal's
         process group.  This is mandated by POSIX. */
      /* This is in accordance with the Posix 1003.1 standard,
         section B.7.2.4, which says that trying to set the terminal
         process group with tcsetpgrp() to an unused pgrp value (like
         this would have for the first child) is an error.  Section
         B.4.3.3, p. 237 also covers this, in the context of job control
         shells. */
      if (setpgid (mine, pipeline_pgrp) < 0)
        fprintf (stderr, "%s: child setpgid (%d to %d) error %d: %s\n",
             shell_name, mine, pipeline_pgrp, errno,
             (char *)strerror (errno));
#if defined (PGRP_PIPE)
      if (pipeline_pgrp == mine)
        {
#endif
          if (!async_p)
        give_terminal_to (pipeline_pgrp);

#if defined (PGRP_PIPE)
          pipe_read (pgrp_pipe);
        }
#endif
    }
      else            /* Without job control... */
    {
      if (!pipeline_pgrp)
        pipeline_pgrp = shell_pgrp;

      /* If these signals are set to SIG_DFL, we encounter the curious
         situation of an interactive ^Z to a running process *working*
         and stopping the process, but being unable to do anything with
         that process to change its state.  On the other hand, if they
         are set to SIG_IGN, jobs started from scripts do not stop when
         the shell running the script gets a SIGTSTP and stops. */

      signal (SIGTSTP, SIG_DFL);
      signal (SIGTTOU, SIG_DFL);
      signal (SIGTTIN, SIG_DFL);

      if (async_p)
        {
          signal (SIGINT, SIG_IGN);
          signal (SIGQUIT, SIG_IGN);
        }
    }

#if defined (PGRP_PIPE)
      /* Release the process group pipe, since our call to setpgid ()
     is done.  The last call to pipe_close is done in stop_pipeline. */
      pipe_close (pgrp_pipe);
#endif /* PGRP_PIPE */

      if (async_p)
    last_asynchronous_pid = getpid ();
    }
  else
    {
      /* In the parent.  Remember the pid of the child just created
     as the proper pgrp if this is the first child. */

      if (job_control)
    {
      if (!pipeline_pgrp)
        {
          pipeline_pgrp = pid;
          /* Don't twiddle terminal pgrps in the parent!  This is the bug,
         not the good thing of twiddling them in the child! */
          /* give_terminal_to (pipeline_pgrp); */
        }
      /* This is done on the recommendation of the Rationale section of
         the POSIX 1003.1 standard, where it discusses job control and
         shells.  It is done to avoid possible race conditions. (Ref.
         1003.1 Rationale, section B.4.3.3, page 236). */
      setpgid (pid, pipeline_pgrp);
    }
      else
    {
      if (!pipeline_pgrp)
        pipeline_pgrp = shell_pgrp;
    }

      /* Place all processes into the jobs array regardless of the
     state of job_control. */
      add_process (command, pid);

      if (async_p)
    last_asynchronous_pid = pid;

      last_made_pid = pid;

      /* Unblock SIGINT and SIGCHLD. */
      sigprocmask (SIG_SETMASK, &oset, (sigset_t *)NULL);
    }

  return (pid);
}

/* When we end a job abnormally, or if we stop a job, we set the tty to the
   state kept in here.  When a job ends normally, we set the state in here
   to the state of the tty. */

#if defined (NEW_TTY_DRIVER)
static struct sgttyb shell_tty_info;
static struct tchars shell_tchars;
static struct ltchars shell_ltchars;
#endif /* NEW_TTY_DRIVER */

#if defined (TERMIO_TTY_DRIVER)
static struct termio shell_tty_info;
#endif /* TERMIO_TTY_DRIVER */

#if defined (TERMIOS_TTY_DRIVER)
static struct termios shell_tty_info;
#endif /* TERMIOS_TTY_DRIVER */

#if defined (NEW_TTY_DRIVER) && defined (DRAIN_OUTPUT)
/* Since the BSD tty driver does not allow us to change the tty modes
   while simultaneously waiting for output to drain and preserving
   typeahead, we have to drain the output ourselves before calling
   ioctl.  We cheat by finding the length of the output queue, and
   using select to wait for an appropriate length of time.  This is
   a hack, and should be labeled as such (it's a hastily-adapted
   mutation of a `usleep' implementation).  It's only reason for
   existing is the flaw in the BSD tty driver. */

static int ttspeeds[] =
{
  0, 50, 75, 110, 134, 150, 200, 300, 600, 1200,
  1800, 2400, 4800, 9600, 19200, 38400
};

static void
draino (fd, ospeed)
     int fd, ospeed;
{
  register int delay = ttspeeds[ospeed];
  int n;

  if (!delay)
    return;

  while ((ioctl (fd, TIOCOUTQ, &n) == 0) && n)
    {
      if (n > (delay / 100))
    {
      struct timeval tv;

      n *= 10;        /* 2 bits more for conservativeness. */
      tv.tv_sec = n / delay;
      tv.tv_usec = ((n % delay) * 1000000) / delay;
      select (fd, (fd_set *)0, (fd_set *)0, (fd_set *)0, &tv);
    }
      else
    break;
    }
}
#endif /* NEW_TTY_DRIVER && DRAIN_OUTPUT */

/* Return the fd from which we are actually getting input.  Should be
   inlined by the compiler. */
static int
input_tty ()
{
  int tty = shell_tty;

  if (tty == -1)
    tty = fileno (stdin);

  return (tty);
}

/* Fill the contents of shell_tty_info with the current tty info. */
get_tty_state ()
{
  int tty = input_tty ();

  if (tty != -1)
    {
#if defined (NEW_TTY_DRIVER)
      ioctl (tty, TIOCGETP, &shell_tty_info);
      ioctl (tty, TIOCGETC, &shell_tchars);
      ioctl (tty, TIOCGLTC, &shell_ltchars);
#endif /* NEW_TTY_DRIVER */

#if defined (TERMIO_TTY_DRIVER)
      ioctl (tty, TCGETA, &shell_tty_info);
#endif /* TERMIO_TTY_DRIVER */

#if defined (TERMIOS_TTY_DRIVER)
      if (tcgetattr (tty, &shell_tty_info) < 0)
    {
      extern int shell_level;

      fprintf (stderr, "%s: [%d: %d] tcgetattr: %s\n", shell_name,
           getpid (), shell_level, (char *)strerror (errno));
    }
#endif /* TERMIOS_TTY_DRIVER */
    }
}

/* Make the current tty use the state in shell_tty_info. */
set_tty_state ()
{
  int tty = input_tty ();

  if (tty != -1)
    {
#if defined (NEW_TTY_DRIVER)
#  if defined (DRAIN_OUTPUT)
      draino (tty, shell_tty_info.sg_ospeed);
#  endif /* DRAIN_OUTPUT */
      ioctl (tty, TIOCSETN, &shell_tty_info);
      ioctl (tty, TIOCSETC, &shell_tchars);
      ioctl (tty, TIOCSLTC, &shell_ltchars);
#endif /* NEW_TTY_DRIVER */

#if defined (TERMIO_TTY_DRIVER)
      ioctl (tty, TCSETAW, &shell_tty_info);
#endif /* TERMIO_TTY_DRIVER */

#if defined (TERMIOS_TTY_DRIVER)
      if (tcsetattr (tty, TCSADRAIN, &shell_tty_info) < 0)
    {
      extern int shell_level;

      fprintf (stderr, "%s: [%d: %d] tcsetattr: %s\n", shell_name,
           getpid (), shell_level, (char *)strerror (errno));
    }
#endif /* TERMIOS_TTY_DRIVER */
    }
}

/* Given an index into the jobs array JOB, return the pid of the last
   process in that job's pipeline.  This is the one whose exit status
   counts. */
static pid_t
last_pid (job)
     int job;
{
  register PROCESS *p;
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);

  p = jobs[job]->pipe;
  while (p->next != jobs[job]->pipe)
    p = p->next;

  UNBLOCK_CHILD (oset);
  return (p->pid);
}

/* Wait for a particular child of the shell to finish executing.
   This low-level function prints an error message if PID is not
   a child of this shell.  It returns -1 if it fails, or 0 if not. */
int
wait_for_single_pid (pid)
     pid_t pid;
{
  register PROCESS *child;

  child = find_pipeline (pid);

  if (!child)
    {
      report_error ("wait: pid %d is not a child of this shell", pid);
      return (127);
    }

  return (wait_for (pid));
}

/* Wait for all of the backgrounds of this shell to finish. */
void
wait_for_background_pids ()
{
  while (1)
    {
      register int i, count = 0;
      sigset_t set, oset;

      BLOCK_CHILD (set, oset);

      for (i = 0; i < job_slots; i++)
    if (jobs[i] && (JOBSTATE (i) == JRUNNING) && !(jobs[i]->foreground))
      {
        count++;
        break;
      }

      if (!count)
    {
      UNBLOCK_CHILD (oset);
      break;
    }

      for (i = 0; i < job_slots; i++)
    if (jobs[i] && (JOBSTATE (i) == JRUNNING) && !jobs[i]->foreground)
      {
        pid_t pid = last_pid (i);
        UNBLOCK_CHILD (oset);
        QUIT;
        wait_for_single_pid (pid);
        break;
      }
    }
}

/* Wait for pid (one of our children) to terminate, then
   return the termination state. */
int
wait_for (pid)
     pid_t pid;
{
  extern int last_command_exit_value;
  int job, termination_state;
  register PROCESS *child;
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);
  termination_state = last_command_exit_value;

  /* If we say wait_for (), then we have a record of this child somewhere.
     If this child and all of its peers are not running, then don't
     sigpause (), since there is no need to. */
 wait_loop:

  /* If the shell is running interactively, and the shell is the foreground
     process (e.g. executing a `wait' command) then let the user C-c out. */
  if (interactive && (terminal_pgrp == shell_pgrp))
    QUIT;

  child = find_pipeline (pid);

  if (!child)
    {
      give_terminal_to (shell_pgrp);
      UNBLOCK_CHILD (oset);
      programming_error ("wait_for: No record of pid %d", pid);
    }

  /* If this child is part of a job, then we are really waiting for the
     job to finish.  Otherwise, we are waiting for the child to finish. */

  job = find_job (pid);

  if (job != NO_JOB)
    {
      register int job_state = 0, any_stopped = 0;
      register PROCESS *p = jobs[job]->pipe;

      do
    {
      job_state |= p->running;
      if (!p->running)
        any_stopped |= WIFSTOPPED (p->status);
      p = p->next;
    }
      while (p != jobs[job]->pipe);

      if (job_state == 0)
    {
      if (any_stopped)
        jobs[job]->state = JSTOPPED;
      else
        jobs[job]->state = JDEAD;
    }
    }

  if (child->running ||
      ((job != NO_JOB) && (JOBSTATE (job) == JRUNNING)))
    {
#if !defined (SCO)
      sigset_t set;

      sigemptyset (&set);
      sigsuspend (&set);
#else /* SCO Unix */
      struct sigaction act, oact;

      act.sa_handler = SIG_DFL;
      sigemptyset (&act.sa_mask);
      act.sa_flags = 0;

      sigaction (SIGCHLD, &act, &oact);
      flush_child (0);
      sigaction (SIGCHLD, &oact, (struct sigaction *)NULL);
#endif /* !SCO */

      goto wait_loop;
    }

  /* The exit state of the command is either the termination state of the
     child, or the termination state of the job.  If a job, the status
     of the last child in the pipeline is the significant one. */

  if (job != NO_JOB)
    {
      register PROCESS *p = jobs[job]->pipe;

      while (p->next != jobs[job]->pipe)
    p = p->next;
      if (WIFSIGNALED (p->status))
    termination_state = 128 + WTERMSIG (p->status);
      else if (!WIFSTOPPED (p->status))
    termination_state = WEXITSTATUS (p->status);
    }
  else
    {
      if (WIFSIGNALED (child->status))
    termination_state = 128 + WTERMSIG (child->status);
      else if (!WIFSTOPPED (child->status))
    termination_state = WEXITSTATUS (child->status);
    }

  if (job == NO_JOB || jobs[job]->job_control)
    give_terminal_to (shell_pgrp);

  /* If the command did not exit cleanly, or the job is just
     being stopped, then reset the tty state back to what it
     was before this command.  Do this only if the shell is
     interactive. */
  if (job != NO_JOB && interactive)
    {
      if (WIFSIGNALED (child->status) || WIFSTOPPED (child->status))
    set_tty_state ();
      else
    get_tty_state ();

      notify_and_cleanup ();
    }

 wait_exit:
  UNBLOCK_CHILD (oset);
  return (termination_state);
}

/* Wait for the last process in the pipeline for JOB. */
int
wait_for_job (job)
     int job;
{
  pid_t pid = last_pid (job);
  return (wait_for (pid));
}

/* Print info about dead jobs, and then delete them from the list
   of known jobs. */
notify_and_cleanup ()
{
  if (interactive)
    notify_of_job_status ();
  cleanup_dead_jobs ();
}

/* Return the next closest (chronologically) job to JOB which is in
   STATE.  STATE can be JSTOPPED, JRUNNING.  NO_JOB is returned if
   there is no next recent job. */
static int
most_recent_job_in_state (job, state)
     int job;
     JOB_STATE state;
{
  register int i;
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);

  for (i = job - 1; i >= 0; i--)
    {
      if (jobs[i])
    {
      if (JOBSTATE (i) == state)
        {
          /* Found it! */
          UNBLOCK_CHILD (oset);
          return (i);
        }
    }
    }
  UNBLOCK_CHILD (oset);
  return (NO_JOB);
}

/* Return the newest *stopped* job older than JOB, or NO_JOB if not
   found. */
static int
last_stopped_job (job)
     int job;
{
  return (most_recent_job_in_state (job, JSTOPPED));
}

/* Return the newest *running* job older than JOB, or NO_JOB if not
   found. */
static int
last_running_job (job)
     int job;
{
  return (most_recent_job_in_state (job, JRUNNING));
}

/* Make JOB be the current job, and make previous be useful. */
static void
set_current_job (job)
     int job;
{
  int candidate = NO_JOB;

  if (current_job != job)
    {
      previous_job = current_job;
      current_job = job;
    }

  /* First choice for previous_job is the old current_job. */
  if (previous_job != current_job &&
      previous_job != NO_JOB &&
      jobs[previous_job] &&
      JOBSTATE (previous_job) == JSTOPPED)
    return;

  /* Second choice:  Newest stopped job that is older than
     the current job. */
  if (JOBSTATE (current_job) == JSTOPPED)
    {
      candidate = last_stopped_job (current_job);

      if (candidate != NO_JOB)
    {
      previous_job = candidate;
      return;
    }
    }

  /* If we get here, there is either only one stopped job, in which case it is
     the current job and the previous job should be set to the newest running
     job, or there are only running jobs and the previous job should be set to
     the newest running job older than the current job.  We decide on which
     alternative to use based on whether or not JOBSTATE(current_job) is
     JSTOPPED. */

  if (JOBSTATE (current_job) == JRUNNING)
    candidate = last_running_job (current_job);
  else
    candidate = last_running_job (job_slots);

  if (candidate != NO_JOB)
    {
      previous_job = candidate;
      return;
    }

  /* There is only a single job, and it is both `+' and `-'. */
  previous_job = current_job;
}

/* Make current_job be something useful, if it isn't already. */

/* Here's the deal:  The newest non-running job should be `+', and the
   next-newest non-running job should be `-'.  If there is only a single
   stopped job, the previous_job is the newest non-running job.  If there
   are only running jobs, the newest running job is `+' and the
   next-newest running job is `-'. */
static void
reset_current ()
{
  int candidate = NO_JOB;

  if (current_job != NO_JOB &&
      job_slots && jobs[current_job] &&
      JOBSTATE (current_job) == JSTOPPED)
    {
      candidate = current_job;
    }
  else
    {
      /* First choice: the previous job! */
      if (previous_job != NO_JOB && jobs[previous_job] &&
      JOBSTATE (previous_job) == JSTOPPED)
    candidate = previous_job;

      /* Second choice: the most recently stopped job. */
      if (candidate == NO_JOB)
    candidate = last_stopped_job (job_slots);

      if (candidate == NO_JOB)
    {
      /* Third choice: the newest running job. */
      candidate = last_running_job (job_slots);
    }
    }

  /* If we found a job to use, then use it.  Otherwise, there
     are no jobs period. */
  if (candidate != NO_JOB)
    set_current_job (candidate);
  else
    current_job = previous_job = NO_JOB;
}

/* Start a job.  FOREGROUND if non-zero says to do that.  Otherwise,
   start the job in the background.  JOB is a zero-based index into
   JOBS.  Returns -1 if it is unable to start a job, and the return
   status of the job otherwise. */
int
start_job (job, foreground)
     int job, foreground;
{
  register PROCESS *p;
  int already_running;
  sigset_t set, oset;
  char *wd;
#if defined (NEW_TTY_DRIVER)
  static struct sgttyb save_stty;
#endif

#if defined (TERMIO_TTY_DRIVER)
  static struct termio save_stty;
#endif

#if defined (TERMIOS_TTY_DRIVER)
  static struct termios save_stty;
#endif

  BLOCK_CHILD (set, oset);
  already_running = (JOBSTATE (job) == JRUNNING);

  if (!foreground && already_running)
    {
      extern char *this_command_name;

      report_error ("%s: bg background job?", this_command_name);
      UNBLOCK_CHILD (oset);
      return (-1);
    }

  wd = job_working_directory ();

  /* You don't know about the state of this job.  Do you? */
  jobs[job]->notified = 0;

  if (foreground)
    {
      set_current_job (job);
      jobs[job]->foreground = 1;
    }

  /* Tell the outside world what we're doing. */
  p = jobs[job]->pipe;

  if (!foreground)
    fprintf (stderr, "[%d]%c ", job + 1,
       (job == current_job) ? '+': ((job == previous_job) ? '-' : ' '));

  do
    {
      fprintf (stderr, "%s%s",
           p->command, p->next != jobs[job]->pipe? " | " : "");
      p = p->next;
    }
  while (p != jobs[job]->pipe);

  if (!foreground)
    fprintf (stderr, " &");

  if (strcmp (wd, jobs[job]->wd) != 0)
    fprintf (stderr, "    (wd: %s)", polite_directory_format (jobs[job]->wd));

  fprintf (stderr, "\n");

  free (wd);

  /* Run the job. */
  if (!already_running)
    {
      /* Each member of the pipeline is now running. */
      p = jobs[job]->pipe;

      do
    {
      if (WIFSTOPPED (p->status))
        p->running = 1;
      p = p->next;
    }
      while (p != jobs[job]->pipe);

      /* This means that the job is running. */
      JOBSTATE (job) = JRUNNING;
    }

  /* Save the tty settings before we start the job in the foreground. */
  if (foreground)
    {
      get_tty_state ();
      save_stty = shell_tty_info;
    }

  /* Give the terminal to this job. */
  if (foreground)
    {
      if (jobs[job]->job_control)
    give_terminal_to (jobs[job]->pgrp);
    }
  else
    jobs[job]->foreground = 0;

  /* If the job is already running, then don't bother jump-starting it. */
  if (!already_running)
    {
      jobs[job]->notified = 1;
      killpg (jobs[job]->pgrp, SIGCONT);
    }

  UNBLOCK_CHILD (oset);

  if (foreground)
    {
      pid_t pid = last_pid (job);
      int s = wait_for (pid);

      shell_tty_info = save_stty;
      set_tty_state ();
      return (s);
    }
  else
    {
      reset_current ();
      return (0);
    }
}

/* Give PID SIGNAL.  This determines what job the pid belongs to (if any).
   If PID does belong to a job, and the job is stopped, then CONTinue the
   job after giving it SIGNAL.  Returns -1 on failure.  If GROUP is non-null,
   then kill the process group associated with PID. */
int
kill_pid (pid, signal, group)
     pid_t pid;
     int signal, group;
{
  register PROCESS *p;
  int job, result = EXECUTION_SUCCESS;
  sigset_t set, oset;

  BLOCK_CHILD (set, oset);
  p = find_pipeline (pid);
  job = find_job (pid);

  if (group)
    {
      if (job != NO_JOB)
    {
      jobs[job]->notified = 0;

      /* Kill process in backquotes or one started without job control? */
      if (jobs[job]->pgrp == shell_pgrp)
        {
          p = jobs[job]->pipe;

          do
        {
          kill (p->pid, signal);
          if (!p->running && (signal == SIGTERM || signal == SIGHUP))
            kill (p->pid, SIGCONT);
          p = p->next;
        } while (p != jobs[job]->pipe);
        }
      else
        {
          result = killpg (jobs[job]->pgrp, signal);
          if (p && (JOBSTATE (job) == JSTOPPED) &&
          (signal == SIGTERM || signal == SIGHUP))
        killpg (jobs[job]->pgrp, SIGCONT);
        }
    }
      else
    {
      result = killpg (pid, signal);
    }
    }
  else
    {
      result = kill (pid, signal);
    }
  UNBLOCK_CHILD (oset);
  return (result);
}

/* Take care of system dependencies that must be handled when waiting for
   children.  The arguments to the WAITPID macro match those to the Posix.1
   waitpid() function. */

#if defined (Ultrix) && defined (mips) && defined (_POSIX_VERSION)
#  define WAITPID(pid, statusp, options) \
    wait3 ((union wait *)statusp, options, (struct rusage *)0)
#else
#  if defined (_POSIX_VERSION)
#    define WAITPID(pid, statusp, options) \
    waitpid ((pid_t)pid, statusp, options)
#  else
#    if defined (hpux)
#      define WAITPID(pid, statusp, options) \
    wait3 (statusp, options, (int *)0)
#    else
#      define WAITPID(pid, statusp, options) \
    wait3 (statusp, options, (struct rusage *)0)
#    endif /* !hpux */
#  endif /* !_POSIX_VERSION */
#endif /* !(Ultrix && mips && _POSIX_VERSION) */

/* If the system needs it, REINSTALL_SIGCHLD_HANDLER will reinstall the
   handler for SIGCHLD. */

#if defined (hpux) && !defined (_POSIX_VERSION)
#  define REINSTALL_SIGCHLD_HANDLER signal (SIGCHLD, flush_child)
#else
#  define REINSTALL_SIGCHLD_HANDLER
#endif /* !hpux || _POSIX_VERSION */

/* Flush_child () flushes at least one of the children that we are waiting for.
   It gets run when we have gotten a SIGCHLD signal, and stops when there
   aren't any children terminating any more.  If SIG is 0, this is to be a
   blocking wait for a single child.  It is here to get around SCO Unix's
   broken sigsuspend (). */

static sighandler
flush_child (sig)
     int sig;
{
  WAIT status;
  PROCESS *child;
  pid_t pid;
  int call_set_current = 0, last_stopped_job = NO_JOB;
  int children_exited = 0;

  do
    {
      pid = WAITPID (-1, &status, sig ? (WNOHANG | WUNTRACED) : WUNTRACED);

      if (pid > 0)
    {
      REINSTALL_SIGCHLD_HANDLER;

      /* Locate our PROCESS for this pid. */
      child = find_pipeline (pid);

      /* It is not an error to have a child terminate that we did
         not have a record of.  This child could have been part of
         a pipeline in backquote substitution. */
      if (child)
        {
          int job = find_job (pid);

          while (child->pid != pid)
        child = child->next;

          /* Remember status, and fact that process is not running. */
          child->status = status;
          child->running = 0;

          if (job != NO_JOB)
        {
          int job_state = 0;
          int any_stopped = 0;

          child = jobs[job]->pipe;
          jobs[job]->notified = 0;

          /* If all children are not running, but any of them is
             stopped, then the job is stopped, not dead. */
          do
           {
              job_state |= child->running;
              if (!child->running)
            any_stopped |= (WIFSTOPPED (child->status));
              child = child->next;
            }
          while (child != jobs[job]->pipe);

          if (job_state == 0)
            {
              if (any_stopped)
            {
              jobs[job]->state = JSTOPPED;
              jobs[job]->foreground = 0;
              call_set_current++;
              last_stopped_job = job;
            }
              else
            {
              jobs[job]->state = JDEAD;

              if (job == last_stopped_job)
                last_stopped_job = NO_JOB;

              /* If this job was not started with job control,
                 then the shell has already seen the SIGINT, since
                 the process groups are the same.  In that case,
                 don't send the SIGINT to the shell; it will
                 surprise people to have a stray interrupt
                 arriving some time after they killed the job. */

              /* XXX - should the `|| interactive' be there? */
              if (jobs[job]->foreground &&
                  (jobs[job]->job_control || interactive) &&
                  WTERMSIG (jobs[job]->pipe->status) == SIGINT)
                kill (getpid (), SIGINT);
            }
            }
        }
        }
      /* If we have caught a child, and a trap was set for SIGCHLD, then
         bump up the count of the number of children that have exited,
         so we know how many times to call it. */
      children_exited++;
    }
    }
#if defined (SCO)
  while (sig && pid > (pid_t)0);   /* Hack for SCO, see earlier comment. */
#else
  while (pid > (pid_t)0);
#endif /* SCO */

  /* If a job was running and became stopped, then set the current
     job.  Otherwise, don't change a thing. */
  if (call_set_current)
    if (last_stopped_job != NO_JOB)
      set_current_job (last_stopped_job);
    else
      reset_current ();

  /* Call a SIGCHLD trap handler for each child that exits, if one is set. */
  {
    extern char *trap_list[];

    if ((trap_list[SIGCHLD] != (char *)DEFAULT_SIG) &&
    (trap_list[SIGCHLD] != (char *)IGNORE_SIG))
      {
    extern int last_command_exit_value;
    /* It's quite dangerous to do this from a signal handler, so
       we turn off the trap list temporarily while we parse and
       execute the command.  This will protect us against (potentially
       infinite) recursive calls.  We also preserve $? around the
       execution of trap commands, by saving and restoring the value
       of last_command_exit_value. */

    char *trap_command = trap_list[SIGCHLD];
    int old_exit_value = last_command_exit_value;
    trap_list[SIGCHLD] = (char *)DEFAULT_SIG;
    while (children_exited--)
      parse_and_execute (savestring (trap_command), "trap");
    trap_list[SIGCHLD] = trap_command;
    last_command_exit_value = old_exit_value;
      }
  }

  /* We have successfully recorded the useful information about this process
     that has just changed state.  If we notify asynchronously, and the job
     that this process belongs to is no longer running, then notify the user
     of that fact now. */
  if (asynchronous_notification && interactive)
    notify_of_job_status ();

#if !defined (VOID_SIGHANDLER)
  return (0);
#endif /* VOID_SIGHANDLER */
}

/* Function to call when you want to notify people of changes
   in job status.  This prints out all jobs which are pending
   notification to stderr, and marks those printed as already
   notified, thus making them candidates for cleanup. */
static void
notify_of_job_status ()
{
  register int job, termsig;
  char *dir = job_working_directory ();
  sigset_t set, oset;

  sigemptyset (&set);
  sigaddset (&set, SIGCHLD);
  sigaddset (&set, SIGTTOU);
  sigemptyset (&oset);
  sigprocmask (SIG_BLOCK, &set, &oset);

  for (job = 0; job < job_slots; job++)
    {
      if (jobs[job] && jobs[job]->notified == 0)
    {
      WAIT s;

      s = jobs[job]->pipe->status;
      termsig = WTERMSIG (s);

      switch (JOBSTATE (job))
        {
          /* Print info on jobs that are running in the background,
         and on foreground jobs that were killed by anything
         except SIGINT. */

        case JDEAD:

          if (jobs[job]->foreground)
        {
          if (termsig && WIFSIGNALED (s) && termsig != SIGINT)
            {
              fprintf (stderr, "%s", sys_siglist[termsig]);

              if (WIFCORED (s))
            fprintf (stderr, " (core dumped)");

              fprintf (stderr, "\n");
            }
        }
          else
        {
          pretty_print_job (job, 0, stderr);
          if (dir && strcmp (dir, jobs[job]->wd) != 0)
            fprintf (stderr,
                 "(wd now: %s)\n", polite_directory_format (dir));
        }
          jobs[job]->notified = 1;
          break;

        case JSTOPPED:
          fprintf (stderr, "\n");
          pretty_print_job (job, 0, stderr);
          if (dir && (strcmp (dir, jobs[job]->wd) != 0))
        fprintf (stderr,
             "(wd now: %s)\n", polite_directory_format (dir));
          jobs[job]->notified = 1;
          break;

        case JRUNNING:
        case JMIXED:
          break;

        default:
          programming_error ("notify_of_job_status");
        }
    }
    }
  free (dir);
  sigprocmask (SIG_SETMASK, &oset, (sigset_t *)NULL);
}

/* getpgrp () varies between systems.  Even systems that claim to be
   Posix.1 compatible lie sometimes (Ultrix, SunOS4, apollo). */
#if defined (_POSIX_VERSION) && !defined (BSD_GETPGRP)
#  define getpgid(p) getpgrp ()
#else
#  define getpgid(p) getpgrp (p)
#endif /* !_POSIX_VERSION || BSD_GETPGRP */

/* Initialize the job control mechanism, and set up the tty stuff. */
initialize_jobs ()
{
  shell_pgrp = getpgid (0);

  if (shell_pgrp == -1)
    {
      fprintf (stderr, "%s: initialize_jobs: getpgrp failed: %s\n",
           shell_name, (char *)strerror (errno));
      exit (1);
    }

  /* We can only have job control if we are interactive?
     I guess that makes sense. */

  if (!interactive)
    {
      job_control = 0;
    }
  else
    {
      /* Make sure that we are using the new line discipline. */

      /* Get our controlling terminal.  If job_control is set, or
     interactive is set, then this is an interactive shell no
     matter what opening /dev/tty returns.  (It sometimes says
     the wrong thing.) */
#if !defined (SCO)
      /* SCO Unix fails attempting job control on /dev/tty. */
      if ((shell_tty = open ("/dev/tty", O_RDWR, 0666)) < 0)
#endif /* !SCO */
    shell_tty = dup (fileno (stdin));

      /* Find the highest unused file descriptor we can. */
      {
    int ignore, nds = getdtablesize ();

    while (--nds > 3)
      {
        if (fcntl (nds, F_GETFD, &ignore) == -1)
          break;
      }

    if (shell_tty != nds && (dup2 (shell_tty, nds) != -1))
      {
        if (shell_tty != fileno (stdin))
          close (shell_tty);
        shell_tty = nds;
      }
      }

#if defined (NeXT)
      /* Compensate for a bug in the NeXT 2.0 /usr/etc/rlogind. */
      if (shell_pgrp == 0)
    {
      shell_pgrp = getpid ();
      setpgid (0, shell_pgrp);
      tcsetpgrp (shell_tty, shell_pgrp);
    }
#endif /* NeXT */

      while ((terminal_pgrp = tcgetpgrp (shell_tty)) != -1)
    {
      if (shell_pgrp != terminal_pgrp)
        {
          SigHandler *old_ttin = (SigHandler *)signal (SIGTTIN, SIG_DFL);
          kill (0, SIGTTIN);
          signal (SIGTTIN, old_ttin);
          continue;
        }
      break;
    }

      if (set_new_line_discipline (shell_tty) < 0)
    {
      fprintf (stderr, "%s: initialize_jobs: line discipline: %s",
           shell_name, (char *)strerror (errno));
      job_control = 0;
    }
      else
    {
      original_pgrp = shell_pgrp;
      shell_pgrp = getpid ();

      if ((original_pgrp != shell_pgrp) &&
          (setpgid (0, shell_pgrp) < 0))
        {
          fprintf (stderr, "%s: initialize_jobs: setpgid: %s\n",
               shell_name, (char *)strerror (errno));

          shell_pgrp = original_pgrp;
        }

      job_control = 1;
      give_terminal_to (shell_pgrp);
    }
    }

  if (shell_tty != fileno (stdin))
    SET_CLOSE_ON_EXEC (shell_tty);

#if !defined (_POSIX_VERSION)
  signal (SIGCHLD, flush_child);
#else
  /* Some Posix job control implementations (like SCO 3.2.x) set signals to
     call sigaction with NOCLDSTOP set in sa_flags.  Make sure we get
     signalled on child status changes by using sigaction instead of
     signal. */
  {
    struct sigaction act;
    act.sa_handler = flush_child;
    sigemptyset (&act.sa_mask);
    sigaddset (&act.sa_mask, SIGCHLD);
    act.sa_flags = 0;
    sigaction (SIGCHLD, &act, (struct sigaction *)NULL);
  }
#endif /* _POSIX_VERSION */

  change_flag_char ('m', job_control ? '-' : '+');

  if (interactive)
    get_tty_state ();
}

/* Set the line discipline to the best this system has to offer.
   Return -1 if this is not possible. */
static int
set_new_line_discipline (tty)
     int tty;
{
#if defined (NEW_TTY_DRIVER)
  int ldisc;

  if (ioctl (tty, TIOCGETD, &ldisc) < 0)
    return (-1);

  if (ldisc != NTTYDISC)
    {
      ldisc = NTTYDISC;

      if (ioctl (tty, TIOCSETD, &ldisc) < 0)
    return (-1);
    }
  return (0);
#endif /* NEW_TTY_DRIVER */

#if defined (TERMIO_TTY_DRIVER)
#  if defined (NTTYDISC)
  if (ioctl (tty, TCGETA, &shell_tty_info) < 0)
    return (-1);

  if (shell_tty_info.c_line != NTTYDISC)
    {
      shell_tty_info.c_line = NTTYDISC;
      if (ioctl (tty, TCSETAW, &shell_tty_info) < 0)
    return (-1);
    }
#  endif /* NTTYDISC */
  return (0);
#endif /* TERMIO_TTY_DRIVER */

#if defined (TERMIOS_TTY_DRIVER)
#if defined (Ultrix) || defined (SunOS4) || defined (aixpc)
  if (tcgetattr (tty, &shell_tty_info) < 0)
    return (-1);

  if (shell_tty_info.c_line != NTTYDISC)
    {
      shell_tty_info.c_line = NTTYDISC;
      if (tcsetattr (tty, TCSADRAIN, &shell_tty_info) < 0)
    return (-1);
    }
#endif /* Ultrix || SunOS4 || aixpc */
  return (0);
#endif /* TERMIOS_TTY_DRIVER */

#if !defined (NEW_TTY_DRIVER) && !defined (TERMIO_TTY_DRIVER) && !defined (TERMIOS_TTY_DRIVER)
  return (-1);
#endif
}

/* Allow or disallow job control to take place.  Returns the old value
   of job_control. */
int
set_job_control (arg)
     int arg;
{
  int old;

  old = job_control;
  job_control = arg;
  return (old);
}

static SigHandler *old_tstp, *old_ttou, *old_ttin;
static SigHandler *old_cont = (SigHandler *)SIG_DFL;
static sighandler stop_signal_handler (), cont_signal_handler ();

/* Setup this shell to handle C-C, etc. */
initialize_job_signals ()
{
  sighandler sigint_sighandler ();

  if (interactive)
    {
      signal (SIGINT, sigint_sighandler);
      signal (SIGTSTP, SIG_IGN);
      signal (SIGTTOU, SIG_IGN);
      signal (SIGTTIN, SIG_IGN);
    }
  else if (job_control)
    {
      old_tstp = (SigHandler *)signal (SIGTSTP, stop_signal_handler);
      old_ttou = (SigHandler *)signal (SIGTTOU, stop_signal_handler);
      old_ttin = (SigHandler *)signal (SIGTTIN, stop_signal_handler);
    }
  /* Leave these things alone for non-interactive shells without job
     control. */
}

/* Here we handle CONT signals. */
static sighandler
cont_signal_handler (sig)
     int sig;
{
  initialize_job_signals ();
  signal (SIGCONT, old_cont);
  kill (getpid (), SIGCONT);

#if !defined (VOID_SIGHANDLER)
  return (0);
#endif /* VOID_SIGHANDLER */
}

/* Here we handle stop signals while we are running not as a login shell. */
static sighandler
stop_signal_handler (sig)
     int sig;
{
  signal (SIGTSTP, old_tstp);
  signal (SIGTTOU, old_ttou);
  signal (SIGTTIN, old_ttin);

  old_cont = (SigHandler *)signal (SIGCONT, cont_signal_handler);

  give_terminal_to (shell_pgrp);

  kill (getpid (), sig);

#if !defined (VOID_SIGHANDLER)
  return (0);
#endif /* VOID_SIGHANDLER */
}

/* Give the terminal to PGRP.  */
give_terminal_to (pgrp)
     pid_t pgrp;
{
  sigset_t set, oset;

  if (job_control)
    {
      sigemptyset (&set);
      sigaddset (&set, SIGTTOU);
      sigaddset (&set, SIGTTIN);
      sigaddset (&set, SIGTSTP);
      sigaddset (&set, SIGCHLD);
      sigemptyset (&oset);
      sigprocmask (SIG_BLOCK, &set, &oset);

      if (tcsetpgrp (shell_tty, pgrp) < 0)
    {
      /* Maybe we should print an error message? */
    }
      else
    terminal_pgrp = pgrp;

      sigprocmask (SIG_SETMASK, &oset, (sigset_t *)NULL);
    }
}

/* Clear out any jobs in the job array.  This is intended to be used by
   children of the shell, who should not have any job structures as baggage
   when they start executing (forking subshells for parenthesized execution
   and functions with pipes are the two that spring to mind). */
delete_all_jobs ()
{
  if (job_slots)
    {
      register int i;

      current_job = previous_job = NO_JOB;

      for (i = 0; i < job_slots; i++)
    if (jobs[i] != (JOB *) NULL)
      delete_job (i);

      free ((char *)jobs);
      job_slots = 0;
    }
}

/* Turn off all traces of job control.  This is run by children of the shell
   which are going to do shellsy things, like wait (), etc. */
without_job_control ()
{
  stop_making_children ();
  start_pipeline ();
  delete_all_jobs ();
  set_job_control (0);
}

#if defined (PGRP_PIPE)
/* Read from the read end of a pipe.  This is how the process group leader
   blocks until all of the processes in a pipeline have been made. */
static void
pipe_read (pp)
     int *pp;
{
  char ch;

  if (pp[1] >= 0)
    {
      close (pp[1]);
      pp[1] = -1;
    }

  if (pp[0] >= 0)
    {
      while (read (pp[0], &ch, 1) == -1 && errno == EINTR)
    continue;
    }
}

/* Close the read and write ends of PP, an array of file descriptors. */
static void
pipe_close (pp)
     int *pp;
{
  if (pp[0] >= 0)
    close (pp[0]);

  if (pp[1] >= 0)
    close (pp[1]);

  pp[0] = pp[1] = -1;
}

/* Functional interface closes our local-to-job-control pipes. */
close_pgrp_pipe ()
{
  pipe_close (pgrp_pipe);
}

#endif /* PGRP_PIPE */

#endif /* JOB_CONTROL */