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