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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
*
* subprocs.c --- choosing, spawning, and killing screenhacks.
*
* xscreensaver, Copyright (c) 1991-2003 Jamie Zawinski <jwz@jwz.org>
* Modified: Copyright (c) 2004 William Jon McCann <mccann@jhu.edu>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*/
#include "config.h"
#include <stdlib.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#ifndef ESRCH
# include <errno.h>
#endif
#include <sys/time.h> /* sys/resource.h needs this for timeval */
# include <sys/wait.h> /* for waitpid() and associated macros */
#ifdef VMS
# include <processes.h>
# include <unixio.h> /* for close */
# include <unixlib.h> /* for getpid */
# define pid_t int
# define fork vfork
#endif /* VMS */
#include <signal.h> /* for the signal names */
#include <glib.h>
#include "subprocs.h"
#if !defined(SIGCHLD) && defined(SIGCLD)
# define SIGCHLD SIGCLD
#endif
/* Semaphore to temporarily turn the SIGCHLD handler into a no-op.
Don't alter this directly -- use block_sigchld() / unblock_sigchld().
*/
static int block_sigchld_handler = 0;
#ifdef HAVE_SIGACTION
sigset_t
#else /* !HAVE_SIGACTION */
int
#endif /* !HAVE_SIGACTION */
block_sigchld (void)
{
#ifdef HAVE_SIGACTION
sigset_t child_set;
sigemptyset (&child_set);
sigaddset (&child_set, SIGCHLD);
sigaddset (&child_set, SIGPIPE);
sigprocmask (SIG_BLOCK, &child_set, 0);
#endif /* HAVE_SIGACTION */
block_sigchld_handler++;
#ifdef HAVE_SIGACTION
return child_set;
#else /* !HAVE_SIGACTION */
return 0;
#endif /* !HAVE_SIGACTION */
}
void
unblock_sigchld (void)
{
#ifdef HAVE_SIGACTION
sigset_t child_set;
sigemptyset (&child_set);
sigaddset (&child_set, SIGCHLD);
sigaddset (&child_set, SIGPIPE);
sigprocmask (SIG_UNBLOCK, &child_set, 0);
#endif /* HAVE_SIGACTION */
block_sigchld_handler--;
}
int
signal_pid (int pid,
int signal)
{
int status = -1;
gboolean verbose = TRUE;
if (block_sigchld_handler)
/* This function should not be called from the signal handler. */
abort();
block_sigchld (); /* we control the horizontal... */
status = kill (pid, signal);
if (verbose && status < 0)
{
if (errno == ESRCH)
g_message ("Child process %lu was already dead.",
(unsigned long) pid);
else
{
char buf [1024];
snprintf (buf, sizeof (buf), "Couldn't kill child process %lu",
(unsigned long) pid);
perror (buf);
}
}
unblock_sigchld ();
if (block_sigchld_handler < 0)
abort ();
return status;
}
#ifndef VMS
void
await_dying_children (int pid,
gboolean debug)
{
while (1)
{
int wait_status = 0;
pid_t kid;
errno = 0;
kid = waitpid (-1, &wait_status, WNOHANG|WUNTRACED);
if (debug)
{
if (kid < 0 && errno)
g_message ("waitpid(%d) ==> %ld (%d)", pid, (long) kid, errno);
else if (kid != 0)
g_message ("waitpid(%d) ==> %ld", pid, (long) kid);
}
/* 0 means no more children to reap.
-1 means error -- except "interrupted system call" isn't a "real"
error, so if we get that, we should just try again. */
if (kid < 0 && errno != EINTR)
break;
}
}
#else /* VMS */
static void await_dying_children (saver_info *si)
{
return;
}
#endif /* VMS */
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