system.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/* only needed in OS X 10.1 and possibly early 10.2 releases */
#include <AvailabilityMacros.h>
#if MAC_OS_X_VERSION_MAX_ALLOWED <= MAC_OS_X_VERSION_10_2 || !defined(MAC_OS_X_VERSION_10_2)

/*
 * Copyright (c) 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *	  notice, this list of conditions and the following disclaimer in the
 *	  documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *	  must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *	  may be used to endorse or promote products derived from this software
 *	  without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.	IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/lib/libc/stdlib/system.c,v 1.6 2000/03/16 02:14:41 jasone Exp $
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)system.c	8.1 (Berkeley) 6/4/93";
#endif   /* LIBC_SCCS and not lint */

#include <sys/wait.h>
#include <signal.h>
#include <unistd.h>
#include <paths.h>
#include <errno.h>

int			system(const char *command);

int
system(const char *command)
{
	pid_t		pid;
	int			pstat;
	struct sigaction ign,
				intact,
				quitact;
	sigset_t	newsigblock,
				oldsigblock;

	if (!command)				/* just checking... */
		return (1);

	/*
	 * Ignore SIGINT and SIGQUIT, block SIGCHLD. Remember to save existing
	 * signal dispositions.
	 */
	ign.sa_handler = SIG_IGN;
	(void) sigemptyset(&ign.sa_mask);
	ign.sa_flags = 0;
	(void) sigaction(SIGINT, &ign, &intact);
	(void) sigaction(SIGQUIT, &ign, &quitact);
	(void) sigemptyset(&newsigblock);
	(void) sigaddset(&newsigblock, SIGCHLD);
	(void) sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
	switch (pid = fork())
	{
		case -1:				/* error */
			break;
		case 0:			/* child */

			/*
			 * Restore original signal dispositions and exec the command.
			 */
			(void) sigaction(SIGINT, &intact, NULL);
			(void) sigaction(SIGQUIT, &quitact, NULL);
			(void) sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
			execl(_PATH_BSHELL, "sh", "-c", command, (char *) NULL);
			_exit(127);
		default:				/* parent */
			do
			{
				pid = wait4(pid, &pstat, 0, (struct rusage *) 0);
			} while (pid == -1 && errno == EINTR);
			break;
	}
	(void) sigaction(SIGINT, &intact, NULL);
	(void) sigaction(SIGQUIT, &quitact, NULL);
	(void) sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
	return (pid == -1 ? -1 : pstat);
}

#endif   /* OS X < 10.3 */