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0
forked from pool/util-linux
util-linux/setctsid.c

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/*
* setctsid.c -- execute a command in a new session and with
* new controlling terminal
*
* derviated from: setctsid.c of Rick Sladkey <jrs@world.std.com>
* In the public domain.
*
* Changed by Werner Fink, <werner@suse.de>
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/syslog.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#define xerror(n) do { int error = errno; \
if (!isatty(fileno(stderr))) \
syslog(LOG_ERR, n ": %s", strerror(error)); \
else \
errno = error, perror(n); \
} while (0)
int main(int argc, char *argv[])
{
int fd;
struct stat buf;
int dofork = 0;
if (argc > 1 && !strcmp(argv[1], "-f")) {
dofork = 1;
argc--;
argv++;
}
if (argc < 3) {
fprintf(stderr, "usage: setctsid [-f] tty program [arg ...]\n");
exit(1);
}
if (stat(argv[1], &buf) < 0) {
perror(argv[1]);
exit(1);
}
if (!(S_ISCHR(buf.st_mode))) {
/* why do we care? */
fprintf(stderr, "%s: not a character device\n", argv[1]);
exit(1);
}
if (dofork) {
switch (fork()) {
case -1:
perror("fork");
exit(1);
case 0:
break;
default:
exit(0);
}
}
if (setsid() < 0) {
perror("setsid");
exit(1);
}
if ((fd = open(argv[1], O_RDWR, 0)) < 0) {
xerror("open");
exit(1);
}
dup2(fd, fileno(stdin));
dup2(fd, fileno(stdout));
dup2(fd, fileno(stderr));
if (isatty(fd)) {
if (ioctl(fileno(stdin), TIOCSCTTY, argv[1]) < 0) {
xerror("ioctl");
exit(1);
}
}
if (fd > fileno(stderr))
close(fd);
execvp(argv[2], argv + 2);
xerror("execvp");
exit(1);
}