nojobs.c

android-w.song.android.widget

/* nojobs.c - functions that make children, remember them, and handle their termination. */

/* This file works under BSD, System V, minix, and Posix systems.  It does
   not implement job control. */

/* Copyright (C) 1987-2009 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "config.h"

#include "bashtypes.h"
#include "filecntl.h"

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

#include <stdio.h>
#include <signal.h>
#include <errno.h>

#if defined (BUFFERED_INPUT)
#  include "input.h"
#endif

/* Need to include this up here for *_TTY_DRIVER definitions. */
#include "shtty.h"

#include "bashintl.h"

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

#include "builtins/builtext.h"	/* for wait_builtin */

#define DEFAULT_CHILD_MAX 32

#if defined (_POSIX_VERSION) || !defined (HAVE_KILLPG)
#  define killpg(pg, sig)		kill(-(pg),(sig))
#endif /* USG || _POSIX_VERSION */

#if !defined (HAVE_SIGINTERRUPT) && !defined (HAVE_POSIX_SIGNALS)
#  define siginterrupt(sig, code)
#endif /* !HAVE_SIGINTERRUPT && !HAVE_POSIX_SIGNALS */

#if defined (HAVE_WAITPID)
#  define WAITPID(pid, statusp, options) waitpid (pid, statusp, options)
#else
#  define WAITPID(pid, statusp, options) wait (statusp)
#endif /* !HAVE_WAITPID */

/* Return the fd from which we are actually getting input. */
#define input_tty() (shell_tty != -1) ? shell_tty : fileno (stderr)

#if !defined (errno)
extern int errno;
#endif /* !errno */

extern int interactive, interactive_shell, login_shell;
extern int subshell_environment;
extern int last_command_exit_value, last_command_exit_signal;
extern int interrupt_immediately;
extern sh_builtin_func_t *this_shell_builtin;
#if defined (HAVE_POSIX_SIGNALS)
extern sigset_t top_level_mask;
#endif
extern procenv_t wait_intr_buf;
extern int wait_signal_received;

pid_t last_made_pid = NO_PID;
pid_t last_asynchronous_pid = NO_PID;

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

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

/* If this is non-zero, $LINES and $COLUMNS are reset after every process
   exits from get_tty_state(). */
int check_window_size;

/* STATUS and FLAGS are only valid if pid != NO_PID
   STATUS is only valid if (flags & PROC_RUNNING) == 0 */
struct proc_status {
  pid_t pid;
  int status;	/* Exit status of PID or 128 + fatal signal number */
  int flags;
};

/* Values for proc_status.flags */
#define PROC_RUNNING	0x01
#define PROC_NOTIFIED	0x02
#define PROC_ASYNC	0x04
#define PROC_SIGNALED	0x10

/* Return values from find_status_by_pid */
#define PROC_BAD	 -1
#define PROC_STILL_ALIVE -2

static struct proc_status *pid_list = (struct proc_status *)NULL;
static int pid_list_size;
static int wait_sigint_received;

static long child_max = -1L;

static void alloc_pid_list __P((void));
static int find_proc_slot __P((void));
static int find_index_by_pid __P((pid_t));
static int find_status_by_pid __P((pid_t));
static int process_exit_status __P((WAIT));
static int find_termsig_by_pid __P((pid_t));
static int get_termsig __P((WAIT));
static void set_pid_status __P((pid_t, WAIT));
static void set_pid_flags __P((pid_t, int));
static void unset_pid_flags __P((pid_t, int));
static int get_pid_flags __P((pid_t));
static void add_pid __P((pid_t, int));
static void mark_dead_jobs_as_notified __P((int));

static sighandler wait_sigint_handler __P((int));
static char *j_strsignal __P((int));

#if defined (HAVE_WAITPID)
static void reap_zombie_children __P((void));
#endif

#if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS)
static int siginterrupt __P((int, int));
#endif

static void restore_sigint_handler __P((void));

/* Allocate new, or grow existing PID_LIST. */
static void
alloc_pid_list ()
{
  register int i;
  int old = pid_list_size;

  pid_list_size += 10;
  pid_list = (struct proc_status *)xrealloc (pid_list, pid_list_size * sizeof (struct proc_status));

  /* None of the newly allocated slots have process id's yet. */
  for (i = old; i < pid_list_size; i++)
    pid_list[i].pid = NO_PID;
}

/* Return the offset within the PID_LIST array of an empty slot.  This can
   create new slots if all of the existing slots are taken. */
static int
find_proc_slot ()
{
  register int i;

  for (i = 0; i < pid_list_size; i++)
    if (pid_list[i].pid == NO_PID)
      return (i);

  if (i == pid_list_size)
    alloc_pid_list ();

  return (i);
}

/* Return the offset within the PID_LIST array of a slot containing PID,
   or the value NO_PID if the pid wasn't found. */
static int
find_index_by_pid (pid)
     pid_t pid;
{
  register int i;

  for (i = 0; i < pid_list_size; i++)
    if (pid_list[i].pid == pid)
      return (i);

  return (NO_PID);
}

/* Return the status of PID as looked up in the PID_LIST array.  A
   return value of PROC_BAD indicates that PID wasn't found. */
static int
find_status_by_pid (pid)
     pid_t pid;
{
  int i;

  i = find_index_by_pid (pid);
  if (i == NO_PID)
    return (PROC_BAD);
  if (pid_list[i].flags & PROC_RUNNING)
    return (PROC_STILL_ALIVE);
  return (pid_list[i].status);
}

static int
process_exit_status (status)
     WAIT status;
{
  if (WIFSIGNALED (status))
    return (128 + WTERMSIG (status));
  else
    return (WEXITSTATUS (status));
}

/* Return the status of PID as looked up in the PID_LIST array.  A
   return value of PROC_BAD indicates that PID wasn't found. */
static int
find_termsig_by_pid (pid)
     pid_t pid;
{
  int i;

  i = find_index_by_pid (pid);
  if (i == NO_PID)
    return (0);
  if (pid_list[i].flags & PROC_RUNNING)
    return (0);
  return (get_termsig ((WAIT)pid_list[i].status));
}

/* Set LAST_COMMAND_EXIT_SIGNAL depending on STATUS.  If STATUS is -1, look
   up PID in the pid array and set LAST_COMMAND_EXIT_SIGNAL appropriately
   depending on its flags and exit status. */
static int
get_termsig (status)
     WAIT status;
{
  if (WIFSTOPPED (status) == 0 && WIFSIGNALED (status))
    return (WTERMSIG (status));
  else
    return (0);
}

/* Give PID the status value STATUS in the PID_LIST array. */
static void
set_pid_status (pid, status)
     pid_t pid;
     WAIT status;
{
  int slot;

#if defined (COPROCESS_SUPPORT)
  coproc_pidchk (pid, status);
#endif

  slot = find_index_by_pid (pid);
  if (slot == NO_PID)
    return;

  pid_list[slot].status = process_exit_status (status);
  pid_list[slot].flags &= ~PROC_RUNNING;
  if (WIFSIGNALED (status))
    pid_list[slot].flags |= PROC_SIGNALED;
  /* If it's not a background process, mark it as notified so it gets
     cleaned up. */
  if ((pid_list[slot].flags & PROC_ASYNC) == 0)
    pid_list[slot].flags |= PROC_NOTIFIED;
}

/* Give PID the flags FLAGS in the PID_LIST array. */
static void
set_pid_flags (pid, flags)
     pid_t pid;
     int flags;
{
  int slot;

  slot = find_index_by_pid (pid);
  if (slot == NO_PID)
    return;

  pid_list[slot].flags |= flags;
}

/* Unset FLAGS for PID in the pid list */
static void
unset_pid_flags (pid, flags)
     pid_t pid;
     int flags;
{
  int slot;

  slot = find_index_by_pid (pid);
  if (slot == NO_PID)
    return;

  pid_list[slot].flags &= ~flags;
}

/* Return the flags corresponding to PID in the PID_LIST array. */
static int
get_pid_flags (pid)
     pid_t pid;
{
  int slot;

  slot = find_index_by_pid (pid);
  if (slot == NO_PID)
    return 0;

  return (pid_list[slot].flags);
}

static void
add_pid (pid, async)
     pid_t pid;
     int async;
{
  int slot;

  slot = find_proc_slot ();

  pid_list[slot].pid = pid;
  pid_list[slot].status = -1;
  pid_list[slot].flags = PROC_RUNNING;
  if (async)
    pid_list[slot].flags |= PROC_ASYNC;
}

static void
mark_dead_jobs_as_notified (force)
     int force;
{
  register int i, ndead;

  /* first, count the number of non-running async jobs if FORCE == 0 */
  for (i = ndead = 0; force == 0 && i < pid_list_size; i++)
    {
      if (pid_list[i].pid == NO_PID)
	continue;
      if (((pid_list[i].flags & PROC_RUNNING) == 0) &&
	   (pid_list[i].flags & PROC_ASYNC))
	ndead++;
    }

  if (child_max < 0)
    child_max = getmaxchild ();
  if (child_max < 0)
    child_max = DEFAULT_CHILD_MAX;

  if (force == 0 && ndead <= child_max)
    return;

  /* If FORCE == 0, we just mark as many non-running async jobs as notified
     to bring us under the CHILD_MAX limit. */
  for (i = 0; i < pid_list_size; i++)
    {
      if (pid_list[i].pid == NO_PID)
	continue;
      if (((pid_list[i].flags & PROC_RUNNING) == 0) &&
	   pid_list[i].pid != last_asynchronous_pid)
	{
	  pid_list[i].flags |= PROC_NOTIFIED;
	  if (force == 0 && (pid_list[i].flags & PROC_ASYNC) && --ndead <= child_max)
	    break;
	}
    }
}

/* Remove all dead, notified jobs from the pid_list. */
int
cleanup_dead_jobs ()
{
  register int i;

#if defined (HAVE_WAITPID)
  reap_zombie_children ();
#endif

  for (i = 0; i < pid_list_size; i++)
    {
      if ((pid_list[i].flags & PROC_RUNNING) == 0 &&
	  (pid_list[i].flags & PROC_NOTIFIED))
	pid_list[i].pid = NO_PID;
    }

#if defined (COPROCESS_SUPPORT)
  coproc_reap ();
#endif

  return 0;
}

void
reap_dead_jobs ()
{
  mark_dead_jobs_as_notified (0);
  cleanup_dead_jobs ();
}

/* Initialize the job control mechanism, and set up the tty stuff. */
initialize_job_control (force)
     int force;
{
  shell_tty = fileno (stderr);

  if (interactive)
    get_tty_state ();
}

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

  /* If this is a login shell we don't wish to be disturbed by
     stop signals. */
  if (login_shell)
    ignore_tty_job_signals ();
}

#if defined (HAVE_WAITPID)
/* Collect the status of all zombie children so that their system
   resources can be deallocated. */
static void
reap_zombie_children ()
{
#  if defined (WNOHANG)
  pid_t pid;
  WAIT status;

  CHECK_TERMSIG;
  while ((pid = waitpid (-1, (int *)&status, WNOHANG)) > 0)
    set_pid_status (pid, status);
#  endif /* WNOHANG */
  CHECK_TERMSIG;
}
#endif /* WAITPID */

#if !defined (HAVE_SIGINTERRUPT) && defined (HAVE_POSIX_SIGNALS)
static int
siginterrupt (sig, flag)
     int sig, flag;
{
  struct sigaction act;

  sigaction (sig, (struct sigaction *)NULL, &act);

  if (flag)
    act.sa_flags &= ~SA_RESTART;
  else
    act.sa_flags |= SA_RESTART;

  return (sigaction (sig, &act, (struct sigaction *)NULL));
}
#endif /* !HAVE_SIGINTERRUPT && HAVE_POSIX_SIGNALS */

/* 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)