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Languguage OS II Version 10-94 (Knowledge Media)(1994).ISO
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bash_114.zip
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bash-1.14.2
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nojobs.c
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1994-06-20
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/* The thing that makes children, remembers them, and contains wait loops. */
/* This file works under BSD, System V, minix, and Posix systems. */
/* Copyright (C) 1987, 1989, 1992 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. */
#include <stdio.h>
#include "bashtypes.h"
#include <signal.h>
#include <setjmp.h>
#include <errno.h>
#include "config.h"
#include "command.h"
#include "general.h"
#include "filecntl.h"
#include "jobs.h"
#include "externs.h"
#if defined (BUFFERED_INPUT)
# include "input.h"
#endif
#if !defined (USG) && !defined (_POSIX_VERSION)
# include <sgtty.h>
#else
# if defined (_POSIX_VERSION)
# include <termios.h>
# else
# include <termio.h>
# if !defined (AIXRT)
# include <sys/ttold.h>
# endif /* !AIXRT */
# endif /* !POSIX_VERSION */
#endif /* USG && _POSIX_VERSION */
#if !defined (SIGABRT)
# define SIGABRT SIGIOT
#endif /* !SIGABRT */
#if defined (USG) || defined (_POSIX_VERSION)
# define killpg(pg, sig) kill(-(pg),(sig))
#endif /* USG || _POSIX_VERSION */
#if defined (USG)
# define siginterrupt(sig, code)
#endif /* USG */
#if defined (_POSIX_VERSION)
# define WAITPID(pid, statusp, options) waitpid (pid, statusp, options)
#else
# define WAITPID(pid, statusp, options) wait (statusp)
#endif /* !_POSIX_VERSION */
#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;
#if defined (_POSIX_VERSION)
extern sigset_t top_level_mask;
#endif
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;
#if defined (_POSIX_VERSION)
static void reap_zombie_children ();
#endif
struct proc_status {
pid_t pid;
int status; /* Exit status of PID or 128 + fatal signal number */
};
static struct proc_status *pid_list = (struct proc_status *)NULL;
static int pid_list_size = 0;
#define PROC_BAD -1
#define PROC_STILL_ALIVE -2
/* 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);
return (pid_list[i].status);
}
/* 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;
slot = find_index_by_pid (pid);
if (slot == NO_PID)
return;
if (WIFSIGNALED (status))
pid_list[slot].status = 128 + WTERMSIG (status);
else
pid_list[slot].status = WEXITSTATUS (status);
}
static void
add_pid (pid)
pid_t pid;
{
int slot;
slot = find_proc_slot ();
pid_list[slot].pid = pid;
pid_list[slot].status = PROC_STILL_ALIVE;
}
int
cleanup_dead_jobs ()
{
register int i;
#if defined (_POSIX_VERSION)
reap_zombie_children ();
#endif
for (i = 0; i < pid_list_size; i++)
if (pid_list[i].status != PROC_STILL_ALIVE)
pid_list[i].pid = NO_PID;
}
/* Initialize the job control mechanism, and set up the tty stuff. */
initialize_jobs ()
{
get_tty_state ();
}
#if !defined (READLINE) && defined (TIOCGWINSZ) && defined (SIGWINCH)
static SigHandler *old_winch;
static sighandler
sigwinch_sighandler (sig)
int sig;
{
struct winsize win;
#if defined (USG) && !defined (_POSIX_VERSION)
set_signal_handler (SIGWINCH, sigwinch_sighandler);
#endif /* USG && !_POSIX_VERSION */
if ((ioctl (0, TIOCGWINSZ, &win) == 0) &&
win.ws_row > 0 && win.ws_col > 0)
set_lines_and_columns (win.ws_row, win.ws_col);
}
#endif /* !READLINE && TIOCGWINSZ && SIGWINCH */
/* Setup this shell to handle C-C, etc. */
void
initialize_job_signals ()
{
set_signal_handler (SIGINT, sigint_sighandler);
#if !defined (READLINE) && defined (TIOCGWINSZ) && defined (SIGWINCH)
set_signal_handler (SIGWINCH, sigwinch_sighandler);
#endif /* !READLINE && TIOCGWINSZ && SIGWINCH */
/* If this is a login shell we don't wish to be disturbed by
stop signals. */
if (login_shell)
{
#if defined (SIGTSTP)
set_signal_handler (SIGTSTP, SIG_IGN);
set_signal_handler (SIGTTOU, SIG_IGN);
set_signal_handler (SIGTTIN, SIG_IGN);
#endif
}
}
#if defined (_POSIX_VERSION)
/* 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;
while ((pid = waitpid (-1, (int *)&status, WNOHANG)) > 0)
set_pid_status (pid, status);
#endif /* WNOHANG */
}
#endif /* _POSIX_VERSION */
/* 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;
{
pid_t pid;
#if defined (_POSIX_VERSION)
int retry = 1;
#endif /* _POSIX_VERSION */
/* Discard saved memory. */
if (command)
free (command);
start_pipeline ();
#if defined (BUFFERED_INPUT)
/* If default_buffered_input is active, we are reading a script. If
the command is asynchronous, we have already duplicated /dev/null
as fd 0, but have not changed the buffered stream corresponding to
the old fd 0. We don't want to sync the stream in this case. */
if (default_buffered_input != -1 &&
(!async_p || default_buffered_input > 0))
sync_buffered_stream (default_buffered_input);
#endif /* BUFFERED_INPUT */
/* Create the child, handle severe errors. */
#if defined (_POSIX_VERSION)
retry_fork:
#endif /* _POSIX_VERSION */
if ((pid = fork ()) < 0)
{
#if defined (_POSIX_VERSION)
/* Posix systems with a non-blocking waitpid () system call available
get another chance after zombies are reaped. */
if (errno == EAGAIN && retry)
{
reap_zombie_children ();
retry = 0;
goto retry_fork;
}
#endif /* _POSIX_VERSION */
internal_error ("fork: %s", strerror (errno));
throw_to_top_level ();
}
if (pid == 0)
{
#if defined (BUFFERED_INPUT)
if (default_buffered_input > 0)
{
close_buffered_fd (default_buffered_input);
default_buffered_input = bash_input.location.buffered_fd = -1;
}
#endif /* BUFFERED_INPUT */
#if defined (_POSIX_VERSION)
/* Restore top-level signal mask. */
sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL);
#endif
/* Ignore INT and QUIT in asynchronous children. */
if (async_p)
{
#if 0
/* This now done by setup_async_signals (). */
set_signal_handler (SIGINT, SIG_IGN);
set_signal_handler (SIGQUIT, SIG_IGN);
#endif
last_asynchronous_pid = getpid ();
}
#if defined (SIGTSTP)
set_signal_handler (SIGTSTP, SIG_DFL);
set_signal_handler (SIGTTIN, SIG_DFL);
set_signal_handler (SIGTTOU, SIG_DFL);
#endif
}
else
{
/* In the parent. */
last_made_pid = pid;
if (async_p)
last_asynchronous_pid = pid;
add_pid (pid);
}
return (pid);
}
/* Wait for a single pid (PID) and return its exit status. */
wait_for_single_pid (pid)
pid_t pid;
{
pid_t got_pid;
WAIT status;
int pstatus;
pstatus = find_status_by_pid (pid);
if (pstatus == PROC_BAD)
return (127);
if (pstatus != PROC_STILL_ALIVE)
return (pstatus);
siginterrupt (SIGINT, 1);
while ((got_pid = WAITPID (pid, &status, 0)) != pid)
{
if (got_pid < 0)
{
if (errno != EINTR && errno != ECHILD)
{
siginterrupt (SIGINT, 0);
file_error ("wait");
}
break;
}
else if (got_pid > 0)
set_pid_status (got_pid, status);
}
set_pid_status (got_pid, status);
siginterrupt (SIGINT, 0);
QUIT;
if (WIFSIGNALED (status))
return (128 + WTERMSIG (status));
else
return (WEXITSTATUS (status));
}
/* Wait for all of the shell's children to exit. */
void
wait_for_background_pids ()
{
pid_t got_pid;
WAIT status;
/* If we aren't using job control, we let the kernel take care of the
bookkeeping for us. wait () will return -1 and set errno to ECHILD
when there are no more unwaited-for child processes on both
4.2 BSD-based and System V-based systems. */
siginterrupt (SIGINT, 1);
/* Wait for ECHILD */
while ((got_pid = WAITPID (-1, &status, 0)) != -1)
set_pid_status (got_pid, status);
if (errno != EINTR && errno != ECHILD)
{
siginterrupt (SIGINT, 0);
file_error("wait");
}
siginterrupt (SIGINT, 0);
QUIT;
}
/* Handle SIGINT while we are waiting for children in a script to exit.
All interrupts are effectively ignored by the shell, but allowed to
kill a running job. */
static sighandler
wait_sigint_handler (sig)
int sig;
{
#if 0
/* Run a trap handler if one has been defined. */
maybe_call_trap_handler (sig);
#endif
#if !defined (VOID_SIGHANDLER)
return (0);
#endif /* !VOID_SIGHANDLER */
}
/* Wait for pid (one of our children) to terminate. This is called only
by the execution code in execute_cmd.c. */
int
wait_for (pid)
pid_t pid;
{
int return_val, pstatus;
pid_t got_pid;
WAIT status;
SigHandler *old_sigint_handler;
pstatus = find_status_by_pid (pid);
if (pstatus == PROC_BAD)
return (0);
if (pstatus != PROC_STILL_ALIVE)
return (pstatus);
/* If we are running a script, ignore SIGINT while we're waiting for
a child to exit. The loop below does some of this, but not all. */
if (!interactive_shell)
old_sigint_handler = set_signal_handler (SIGINT, wait_sigint_handler);
while ((got_pid = WAITPID (-1, &status, 0)) != pid) /* XXX was pid now -1 */
{
if (got_pid < 0 && errno == ECHILD)
{
#if !defined (_POSIX_VERSION)
status.w_termsig = status.w_retcode = 0;
#else
status = 0;
#endif /* _POSIX_VERSION */
break;
}
else if (got_pid < 0 && errno != EINTR)
programming_error ("got errno %d while waiting for %d", errno, pid);
else if (got_pid > 0)
set_pid_status (got_pid, status);
}
set_pid_status (got_pid, status);
#if defined (_POSIX_VERSION)
if (got_pid >= 0)
reap_zombie_children ();
#endif /* _POSIX_VERSION */
if (!interactive_shell)
{
set_signal_handler (SIGINT, old_sigint_handler);
/* If the job exited because of SIGINT, make sure the shell acts as if
it had received one also. */
if (WIFSIGNALED (status) && (WTERMSIG (status) == SIGINT))
{
if (maybe_call_trap_handler (SIGINT) == 0)
(*old_sigint_handler) (SIGINT);
}
}
/* Default return value. */
/* ``a full 8 bits of status is returned'' */
if (WIFSIGNALED (status))
return_val = 128 + WTERMSIG (status);
else
return_val = WEXITSTATUS (status);
if (!WIFSTOPPED (status) && WIFSIGNALED (status) &&
(WTERMSIG (status) != SIGINT))
{
fprintf (stderr, "%s", strsignal (WTERMSIG (status)));
if (WIFCORED (status))
fprintf (stderr, " (core dumped)");
fprintf (stderr, "\n");
}
if (interactive_shell && !subshell_environment)
{
if (WIFSIGNALED (status) || WIFSTOPPED (status))
set_tty_state ();
else
get_tty_state ();
}
return (return_val);
}
/* 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;
{
int result;
if (group)
result = killpg (pid, signal);
else
result = kill (pid, signal);
return (result);
}
#if defined (_POSIX_VERSION)
static struct termios shell_tty_info;
#else
# if defined (USG)
static struct termio shell_tty_info;
# else
static struct sgttyb shell_tty_info;
# endif /* USG */
#endif /* _POSIX_VERSION */
static int got_tty_state = 0;
/* Fill the contents of shell_tty_info with the current tty info. */
get_tty_state ()
{
int tty = open ("/dev/tty", O_RDONLY);
if (tty != -1)
{
#if defined (_POSIX_VERSION)
tcgetattr (tty, &shell_tty_info);
#else
# if defined (USG)
ioctl (tty, TCGETA, &shell_tty_info);
# else
ioctl (tty, TIOCGETP, &shell_tty_info);
# endif
#endif
close (tty);
got_tty_state = 1;
}
}
/* Make the current tty use the state in shell_tty_info. */
set_tty_state ()
{
int tty = open ("/dev/tty", O_RDONLY);
if (tty != -1)
{
if (!got_tty_state)
{
close (tty);
return;
}
#if defined (_POSIX_VERSION)
tcsetattr (tty, TCSADRAIN, &shell_tty_info);
#else
# if defined (USG)
ioctl (tty, TCSETAW, &shell_tty_info); /* Wait for output, no flush */
# else
ioctl (tty, TIOCSETN, &shell_tty_info);
# endif
#endif
close (tty);
}
}
/* Give the terminal to PGRP. */
give_terminal_to (pgrp)
pid_t pgrp;
{
}
/* Stop a pipeline. */
stop_pipeline (async, ignore)
int async;
COMMAND *ignore;
{
already_making_children = 0;
}
void
start_pipeline ()
{
already_making_children = 1;
}
/* Print descriptive information about the job with leader pid PID. */
void
describe_pid (pid)
pid_t pid;
{
fprintf (stderr, "%d\n", (int) pid);
}