Peter Wemm 7d1ffcb72a vfork(2) was listed as deprecated in 1994 (r1573) and was the false
reports of its impending demise were removed in 2009 (r199257).

However, in 1996 (r16117) system(3) was switched from vfork(2) to
fork(2) based partly on this.  Switch back to vfork(2).  This has a
dramatic effect in cases of extreme mmap use - such as excessive
abuse (500+) of shared libraries.

popen(3) has used vfork(2) for a while.  vfork(2) isn't going anywhere.
2013-08-13 20:38:55 +00:00

98 lines
3.4 KiB
C

/*
* 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. 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.
*/
#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/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <unistd.h>
#include <paths.h>
#include <errno.h>
#include "un-namespace.h"
#include "libc_private.h"
int
__system(const char *command)
{
pid_t pid, savedpid;
int pstat;
struct sigaction ign, intact, quitact;
sigset_t newsigblock, oldsigblock;
if (!command) /* just checking... */
return(1);
(void)sigemptyset(&newsigblock);
(void)sigaddset(&newsigblock, SIGCHLD);
(void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
switch(pid = vfork()) {
case -1: /* error */
(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
return (-1);
case 0: /* child */
/*
* Restore original signal dispositions and exec the command.
*/
(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
_exit(127);
}
/*
* If we are running means that the child has either completed
* its execve, or has failed.
* Block SIGINT/QUIT because sh -c handles it and wait for
* it to clean up.
*/
memset(&ign, 0, sizeof(ign));
ign.sa_handler = SIG_IGN;
(void)sigemptyset(&ign.sa_mask);
(void)_sigaction(SIGINT, &ign, &intact);
(void)_sigaction(SIGQUIT, &ign, &quitact);
savedpid = pid;
do {
pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
} while (pid == -1 && errno == EINTR);
(void)_sigaction(SIGINT, &intact, NULL);
(void)_sigaction(SIGQUIT, &quitact, NULL);
(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
return(pid == -1 ? -1 : pstat);
}
__weak_reference(__system, system);
__weak_reference(__system, _system);