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/*
* Copyright 2008-2013 Various Authors
* Copyright 2005 Timo Hirvonen
*
* This program 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 of the
* License, or (at your option) any later version.
*
* This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "spawn.h"
#include "file.h"
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
int spawn(char *argv[], int *status, int do_wait)
{
pid_t pid;
int err_pipe[2];
if (pipe(err_pipe) == -1)
return -1;
pid = fork();
if (pid == -1) {
/* error */
return -1;
} else if (pid == 0) {
/* child */
int dev_null, err, i;
/* create grandchild and exit child to avoid zombie processes */
if (!do_wait) {
switch (fork()) {
case 0:
/* grandchild */
break;
case -1:
/* error */
_exit(127);
default:
/* parent of grandchild */
_exit(0);
}
}
close(err_pipe[0]);
fcntl(err_pipe[1], F_SETFD, FD_CLOEXEC);
/* redirect stdout and stderr to /dev/null if possible */
dev_null = open("/dev/null", O_WRONLY);
if (dev_null != -1) {
dup2(dev_null, 1);
dup2(dev_null, 2);
}
/* not interactive, close stdin */
close(0);
/* close unused fds */
for (i = 3; i < 30; i++)
close(i);
execvp(argv[0], argv);
/* error */
err = errno;
write_all(err_pipe[1], &err, sizeof(int));
exit(1);
} else {
/* parent */
int rc, errno_save, child_errno, tmp;
close(err_pipe[1]);
rc = read_all(err_pipe[0], &child_errno, sizeof(int));
errno_save = errno;
close(err_pipe[0]);
if (!do_wait)
status = &tmp;
waitpid(pid, status, 0);
if (rc == -1) {
errno = errno_save;
return -1;
}
if (rc == sizeof(int)) {
errno = child_errno;
return -1;
}
if (rc != 0) {
errno = EMSGSIZE;
return -1;
}
return 0;
}
}
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