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/* intr 1.4 - run a command with interrupts enabled
* Author: Kees J. Bot
* 17 Dec 1992
*/
#define nil 0
#ifndef _POSIX_SOURCE
#define _POSIX_SOURCE 1
#endif
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if __minix
static char DEV_LOG[]= "/dev/log";
#else
static char DEV_LOG[]= "/dev/console";
#endif
static void say(const char *s)
{
write(2, s, strlen(s));
}
static void fatal(const char *label)
{
int err= errno;
say("intr: ");
say(label);
say(": ");
say(strerror(err));
say("\n");
exit(1);
}
static void usage(void)
{
say("Usage: intr [-d] [-t seconds] command [arg ...]\n");
exit(1);
}
int main(int argc, char **argv)
{
int fd;
unsigned n= 0;
int daemonize= 0;
int i;
i= 1;
while (i < argc && argv[i][0] == '-') {
char *opt= argv[i++]+1, *end;
unsigned long sec;
if (opt[0] == '-' && opt[1] == 0) break;
while (*opt != 0) switch (*opt++) {
case 'd':
/* -d */
daemonize= 1;
break;
case 't':
/* -t n: alarm in n seconds. */
if (*opt == 0) {
if (i == argc) usage();
opt= argv[i++];
}
sec= strtoul(opt, &end, 10);
if (end == opt || *end != 0 || (n= sec) != sec)
usage();
opt= "";
break;
default:
usage();
}
}
if ((argc - i) < 1) usage();
/* Try to open the controlling tty. */
if ((fd= open("/dev/tty", O_RDWR)) < 0) {
if (errno != ENXIO) fatal("/dev/tty");
}
if (!daemonize) {
/* Bring to the foreground. If we already have a controlling
* tty then use it. Otherwise try to allocate the console as
* controlling tty and begin a process group.
*/
if (fd < 0) {
if (setsid() < 0) fatal("setsid()");
fd= open("/dev/console", O_RDWR);
}
if (fd >= 0) {
if (fd != 0) {
dup2(fd, 0);
close(fd);
}
dup2(0, 1);
dup2(0, 2);
}
/* Set the usual signals back to the default. */
signal(SIGHUP, SIG_DFL);
signal(SIGINT, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
signal(SIGTERM, SIG_DFL);
} else {
/* Send to the background. Redirect input to /dev/null, and
* output to the log device. Detach from the process group.
*/
if (fd >= 0) {
close(fd);
if (setsid() < 0) fatal("setsid()");
}
if ((fd= open("/dev/null", O_RDWR)) < 0) fatal("/dev/null");
if (fd != 0) {
dup2(fd, 0);
close(fd);
}
if ((fd= open(DEV_LOG, O_WRONLY)) < 0) fatal(DEV_LOG);
if (fd != 1) {
dup2(fd, 1);
close(fd);
}
dup2(1, 2);
/* Move to the root directory. */
(void) chdir("/");
}
/* Schedule the alarm. (It is inherited over execve.) */
if (n != 0) alarm(n);
/* Call program. */
execvp(argv[i], argv + i);
/* Complain. */
fatal(argv[i]);
return 0;
}
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