blob: ca9b9fad805827812d419a19c49af4a4371aea59 [file] [log] [blame]
/* The thing that makes children, remembers them, and contains wait loops. */
/* This file works under BSD, System V, minix, and Posix systems. It does
not implement job control. */
/* 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 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. */
#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"
#if !defined (STRUCT_WINSIZE_IN_SYS_IOCTL)
/* For struct winsize on SCO */
/* sys/ptem.h has winsize but needs mblk_t from sys/stream.h */
# if defined (HAVE_SYS_PTEM_H) && defined (TIOCGWINSZ) && defined (SIGWINCH)
# if defined (HAVE_SYS_STREAM_H)
# include <sys/stream.h>
# endif
# include <sys/ptem.h>
# endif /* HAVE_SYS_PTEM_H && TIOCGWINSZ && SIGWINCH */
#endif /* !STRUCT_WINSIZE_IN_SYS_IOCTL */
#include "shell.h"
#include "jobs.h"
#include "builtins/builtext.h" /* for wait_builtin */
#if !defined (CHILD_MAX)
# define CHILD_MAX 32
#endif
#if defined (_POSIX_VERSION) || !defined (HAVE_KILLPG)
# define killpg(pg, sig) kill(-(pg),(sig))
#endif /* USG || _POSIX_VERSION */
#if !defined (HAVE_SIGINTERRUPT)
# define siginterrupt(sig, code)
#endif /* !HAVE_SIGINTERRUPT */
#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 */
#if defined (READLINE)
extern void rl_set_screen_size __P((int, int));
#endif
extern int interactive, interactive_shell, login_shell;
extern int subshell_environment;
extern int last_command_exit_value;
extern int interrupt_immediately;
extern Function *this_shell_builtin;
#if defined (HAVE_POSIX_SIGNALS)
extern sigset_t top_level_mask;
#endif
extern procenv_t wait_intr_buf;
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;
#if defined (HAVE_WAITPID)
static void reap_zombie_children ();
#endif
static int wait_sigint_received;
/* 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
static struct proc_status *pid_list = (struct proc_status *)NULL;
static int pid_list_size;
/* Return values from find_status_by_pid */
#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);
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));
}
/* 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;
pid_list[slot].status = process_exit_status (status);
pid_list[slot].flags &= ~PROC_RUNNING;
/* 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;
}
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 (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;
}
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 ();
}
#if defined (TIOCGWINSZ) && defined (SIGWINCH)
static SigHandler *old_winch = (SigHandler *)SIG_DFL;
static void
get_new_window_size (from_sig)
int from_sig;
{
struct winsize win;
int tty;
tty = input_tty ();
if (tty >= 0 && (ioctl (tty, TIOCGWINSZ, &win) == 0) &&
win.ws_row > 0 && win.ws_col > 0)
{
#if defined (aixpc)
shell_tty_info.c_winsize = win; /* structure copying */
#endif
sh_set_lines_and_columns (win.ws_row, win.ws_col);
#if defined (READLINE)
rl_set_screen_size (win.ws_row, win.ws_col);
#endif
}
}
static sighandler
sigwinch_sighandler (sig)
int sig;
{
#if defined (MUST_REINSTALL_SIGHANDLERS)
set_signal_handler (SIGWINCH, sigwinch_sighandler);
#endif /* MUST_REINSTALL_SIGHANDLERS */
get_new_window_size (1);
}
#else
static void
get_new_window_size (from_sig)
int from_sig;
{
}
#endif /* TIOCGWINSZ && SIGWINCH */
void
set_sigwinch_handler ()
{
#if defined (TIOCGWINSZ) && defined (SIGWINCH)
old_winch = set_signal_handler (SIGWINCH, sigwinch_sighandler);
#endif
}
void
unset_sigwinch_handler ()
{
#if defined (TIOCGWINSZ) && defined (SIGWINCH)
set_signal_handler (SIGWINCH, old_winch);
#endif
}
/* Setup this shell to handle C-C, etc. */
void
initialize_job_signals ()
{
set_signal_handler (SIGINT, sigint_sighandler);
set_sigwinch_handler ();
/* 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;
while ((pid = waitpid (-1, (int *)&status, WNOHANG)) > 0)
set_pid_status (pid, status);
#endif
}
#endif /* WAITPID && WNOHANG */
/* 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 (HAVE_WAITPID)
int retry = 1;
#endif /* HAVE_WAITPID */
/* 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 (HAVE_WAITPID)
retry_fork:
#endif /* HAVE_WAITPID */
if ((pid = fork ()) < 0)
{
#if defined (HAVE_WAITPID)
/* 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 /* HAVE_WAITPID */
sys_error ("fork");
throw_to_top_level ();
}
if (pid == 0)
{
#if defined (BUFFERED_INPUT)
unset_bash_input (0);
#endif /* BUFFERED_INPUT */
#if defined (HAVE_POSIX_SIGNALS)
/* 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)
last_asynchronous_pid = getpid ();
default_tty_job_signals ();
}
else
{
/* In the parent. */
last_made_pid = pid;
if (async_p)
last_asynchronous_pid = pid;
add_pid (pid, async_p);
}
return (pid);
}
void
ignore_tty_job_signals ()
{
#if defined (SIGTSTP)
set_signal_handler (SIGTSTP, SIG_IGN);
set_signal_handler (SIGTTIN, SIG_IGN);
set_signal_handler (SIGTTOU, SIG_IGN);
#endif
}
void
default_tty_job_signals ()
{
#if defined (SIGTSTP)
set_signal_handler (SIGTSTP, SIG_DFL);
set_signal_handler (SIGTTIN, SIG_DFL);
set_signal_handler (SIGTTOU, SIG_DFL);
#endif
}
/* Wait for a single pid (PID) and return its exit status. Called by
the wait builtin. */
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)
{
internal_error ("wait: pid %d is not a child of this shell", pid);
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);
sys_error ("wait");
}
break;
}
else if (got_pid > 0)
set_pid_status (got_pid, status);
}
set_pid_status (got_pid, status);
set_pid_flags (got_pid, PROC_NOTIFIED);
siginterrupt (SIGINT, 0);
QUIT;
return (process_exit_status (status));
}
/* Wait for all of the shell's children to exit. Called by the `wait'
builtin. */
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);
sys_error("wait");
}
siginterrupt (SIGINT, 0);
QUIT;
mark_dead_jobs_as_notified (1);
cleanup_dead_jobs ();
}
/* Make OLD_SIGINT_HANDLER the SIGINT signal handler. */
#define INVALID_SIGNAL_HANDLER (SigHandler *)wait_for_background_pids
static SigHandler *old_sigint_handler = INVALID_SIGNAL_HANDLER;
static void
restore_sigint_handler ()
{
if (old_sigint_handler != INVALID_SIGNAL_HANDLER)
{
set_signal_handler (SIGINT, old_sigint_handler);
old_sigint_handler = INVALID_SIGNAL_HANDLER;
}
}
/* 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;
{
SigHandler *sigint_handler;
/* If we got a SIGINT while in `wait', and SIGINT is trapped, do
what POSIX.2 says (see builtins/wait.def for more info). */
if (this_shell_builtin && this_shell_builtin == wait_builtin &&
signal_is_trapped (SIGINT) &&
((sigint_handler = trap_to_sighandler (SIGINT)) == trap_handler))
{
last_command_exit_value = EXECUTION_FAILURE;
restore_sigint_handler ();
interrupt_immediately = 0;
trap_handler (SIGINT); /* set pending_traps[SIGINT] */
longjmp (wait_intr_buf, 1);
}
if (interrupt_immediately)
{
last_command_exit_value = EXECUTION_FAILURE;
restore_sigint_handler ();
ADDINTERRUPT;
QUIT;
}
wait_sigint_received = 1;
SIGRETURN (0);
}
/* 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;
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. */
wait_sigint_received = 0;
if (interactive_shell == 0)
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 ("wait_for(%d): %s", pid, strerror(errno));
else if (got_pid > 0)
set_pid_status (got_pid, status);
}
set_pid_status (got_pid, status);
#if defined (HAVE_WAITPID)
if (got_pid >= 0)
reap_zombie_children ();
#endif /* HAVE_WAITPID */
if (interactive_shell == 0)
{
SigHandler *temp_handler;
temp_handler = old_sigint_handler;
restore_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)
{
if (temp_handler == SIG_DFL)
termination_unwind_protect (SIGINT);
else if (temp_handler != INVALID_SIGNAL_HANDLER && temp_handler != SIG_IGN)
(*temp_handler) (SIGINT);
}
}
}
/* Default return value. */
/* ``a full 8 bits of status is returned'' */
return_val = process_exit_status (status);
#if !defined (DONT_REPORT_SIGPIPE)
if ((WIFSTOPPED (status) == 0) && WIFSIGNALED (status) &&
(WTERMSIG (status) != SIGINT))
#else
if ((WIFSTOPPED (status) == 0) && WIFSIGNALED (status) &&
(WTERMSIG (status) != SIGINT) && (WTERMSIG (status) != SIGPIPE))
#endif
{
fprintf (stderr, "%s", strsignal (WTERMSIG (status)));
if (WIFCORED (status))
fprintf (stderr, " (core dumped)");
fprintf (stderr, "\n");
}
if (interactive_shell && subshell_environment == 0)
{
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;
result = group ? killpg (pid, signal) : kill (pid, signal);
return (result);
}
static TTYSTRUCT shell_tty_info;
static int got_tty_state;
/* Fill the contents of shell_tty_info with the current tty info. */
get_tty_state ()
{
int tty;
tty = input_tty ();
if (tty != -1)
{
ttgetattr (tty, &shell_tty_info);
got_tty_state = 1;
if (check_window_size)
get_new_window_size (0);
}
}
/* Make the current tty use the state in shell_tty_info. */
int
set_tty_state ()
{
int tty;
tty = input_tty ();
if (tty != -1)
{
if (got_tty_state == 0)
return 0;
ttsetattr (tty, &shell_tty_info);
}
return 0;
}
/* Give the terminal to PGRP. */
give_terminal_to (pgrp, force)
pid_t pgrp;
int force;
{
}
/* Stop a pipeline. */
stop_pipeline (async, ignore)
int async;
COMMAND *ignore;
{
already_making_children = 0;
}
void
start_pipeline ()
{
already_making_children = 1;
}
int
get_job_by_pid (pid, block)
pid_t pid;
int block;
{
int i;
i = find_index_by_pid (pid);
return ((i == NO_PID) ? PROC_BAD : i);
}
/* Print descriptive information about the job with leader pid PID. */
void
describe_pid (pid)
pid_t pid;
{
fprintf (stderr, "%d\n", (int) pid);
}
void
unfreeze_jobs_list ()
{
}
int
count_all_jobs ()
{
return 0;
}