mirror of
https://github.com/troglobit/finit.git
synced 2026-10-02 05:52:48 +07:00
Joachim Wiberg
27ba3b27f5
serv: add support for foregrounding, running with and without PID file,
including custom PID filename.
test: verify Finit can start & monitor services that:
1) Fork and creates a PID file in a known location
2) Don't fork and don't create a PID file, but Finit does
3) Don't fork but create a PID file
4) Don't fork and create custom named PID file
Note: Finit cannot support a service that forks and doesn't create a PID
file. This combination is impossible to support without tracking
all processes created in /proc -- which Finit does not do atm.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
111 lines
2.0 KiB
C
111 lines
2.0 KiB
C
/*
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* Basic UNIX daemon
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*
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* Options to run in foreground and to create a PID file. When running
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* in foregrund it does not create a PID file by default.
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*/
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#include <err.h>
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#include <paths.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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#define PROGNM "serv"
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static void sig(int signo)
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{
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warnx("We got signal %d ...", signo);
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exit(0);
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}
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static void pidfile(char *pidfn)
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{
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char fn[80];
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pid_t pid;
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FILE *fp;
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if (!pidfn) {
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snprintf(fn, sizeof(fn), "%s%s.pid", _PATH_VARRUN, PROGNM);
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pidfn = fn;
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}
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pid = getpid();
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warnx("Creating PID file %s with %d", pidfn, pid);
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fp = fopen(pidfn, "w");
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if (!fp)
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exit(1);
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fprintf(fp, "%d\n", pid);
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fclose(fp);
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}
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static int usage(int rc)
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{
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FILE *fp = rc ? stderr : stdout;
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fprintf(fp,
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"%s [-nhp] [-P FILE]\n"
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"\n"
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" -n Run in foreground\n"
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" -h Show help text (this)\n"
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" -p Create PID file despite running in foreground\n"
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" -P FILE Create PID file using FILE\n"
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"\n"
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"By default this program daemonizes itself to the background, and,\n"
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"when it's done setting up its signal handler(s), creates a PID file\n"
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"to let the rest of the system know it's done. When the program runs\n"
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"in the foreground it does not create a PID file by default.\n",
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PROGNM);
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return rc;
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}
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int main(int argc, char *argv[])
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{
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int do_background = 1;
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int do_pidfile = 1;
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char *pidfn = NULL;
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int c;
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while ((c = getopt(argc, argv, "hnpP:")) != EOF) {
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switch (c) {
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case 'h':
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return usage(0);
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case 'n':
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do_background = 0;
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do_pidfile--;
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break;
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case 'p':
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do_pidfile++;
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break;
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case 'P':
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pidfn = optarg;
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break;
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default:
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return usage(1);
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}
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}
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/* Daemonize, fork to background etc. */
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if (do_background) {
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if (daemon(0, 1))
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return 1;
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}
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/* Signal handlers first *then* PID file */
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signal(SIGTERM, sig);
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/* Tell world where we are, but not if bg w/o pid file */
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if (do_pidfile == 1)
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pidfile(pidfn);
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warnx("Entering while(1) loop");
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while (1)
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sleep(1);
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warnx("Leaving ...");
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return 0;
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}
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