minix/lib/libc/stdlib/system.c

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/* $NetBSD: system.c,v 1.24 2012/06/25 22:32:45 abs Exp $ */
/*
* 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.
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)system.c 8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: system.c,v 1.24 2012/06/25 22:32:45 abs Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <paths.h>
#include "env.h"
#include "reentrant.h"
int
system(const char *command)
{
pid_t pid;
struct sigaction intsa, quitsa, sa;
sigset_t nmask, omask;
int pstat;
const char *argp[] = {"sh", "-c", NULL, NULL};
argp[2] = command;
/*
* ISO/IEC 9899:1999 in 7.20.4.6 describes this special case.
* We need to check availability of a command interpreter.
*/
if (command == NULL) {
if (access(_PATH_BSHELL, X_OK) == 0)
return 1;
return 0;
}
sa.sa_handler = SIG_IGN;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
if (sigaction(SIGINT, &sa, &intsa) == -1)
return -1;
if (sigaction(SIGQUIT, &sa, &quitsa) == -1) {
sigaction(SIGINT, &intsa, NULL);
return -1;
}
sigemptyset(&nmask);
sigaddset(&nmask, SIGCHLD);
if (sigprocmask(SIG_BLOCK, &nmask, &omask) == -1) {
sigaction(SIGINT, &intsa, NULL);
sigaction(SIGQUIT, &quitsa, NULL);
return -1;
}
(void)__readlockenv();
switch(pid = vfork()) {
case -1: /* error */
(void)__unlockenv();
sigaction(SIGINT, &intsa, NULL);
sigaction(SIGQUIT, &quitsa, NULL);
(void)sigprocmask(SIG_SETMASK, &omask, NULL);
return -1;
case 0: /* child */
sigaction(SIGINT, &intsa, NULL);
sigaction(SIGQUIT, &quitsa, NULL);
(void)sigprocmask(SIG_SETMASK, &omask, NULL);
execve(_PATH_BSHELL, __UNCONST(argp), environ);
_exit(127);
}
(void)__unlockenv();
while (waitpid(pid, &pstat, 0) == -1) {
if (errno != EINTR) {
pstat = -1;
break;
}
}
sigaction(SIGINT, &intsa, NULL);
sigaction(SIGQUIT, &quitsa, NULL);
(void)sigprocmask(SIG_SETMASK, &omask, NULL);
return (pstat);
}