/*- * Copyright (c) 1999 Berkeley Software Design, Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Berkeley Software Design Inc's name may not be used to endorse or * promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * From BSDI: daemon.c,v 1.2 1996/08/15 01:11:09 jch Exp */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include static void dummy_sighandler(int); static void restrict_process(const char *); static int wait_child(pid_t pid, sigset_t *mask); static void usage(void); int main(int argc, char *argv[]) { struct pidfh *ppfh, *pfh; sigset_t mask, oldmask; int ch, nochdir, noclose, restart, serrno; const char *pidfile, *ppidfile, *user; pid_t otherpid, pid; nochdir = noclose = 1; restart = 0; ppidfile = pidfile = user = NULL; while ((ch = getopt(argc, argv, "cfp:P:ru:")) != -1) { switch (ch) { case 'c': nochdir = 0; break; case 'f': noclose = 0; break; case 'p': pidfile = optarg; break; case 'P': ppidfile = optarg; break; case 'r': restart = 1; break; case 'u': user = optarg; break; default: usage(); } } argc -= optind; argv += optind; if (argc == 0) usage(); ppfh = pfh = NULL; /* * Try to open the pidfile before calling daemon(3), * to be able to report the error intelligently */ if (pidfile != NULL) { pfh = pidfile_open(pidfile, 0600, &otherpid); if (pfh == NULL) { if (errno == EEXIST) { errx(3, "process already running, pid: %d", otherpid); } err(2, "pidfile ``%s''", pidfile); } } /* Do the same for actual daemon process. */ if (ppidfile != NULL) { ppfh = pidfile_open(ppidfile, 0600, &otherpid); if (ppfh == NULL) { serrno = errno; pidfile_remove(pfh); errno = serrno; if (errno == EEXIST) { errx(3, "process already running, pid: %d", otherpid); } err(2, "ppidfile ``%s''", ppidfile); } } if (daemon(nochdir, noclose) == -1) { warn("daemon"); goto exit; } /* Write out parent pidfile if needed. */ pidfile_write(ppfh); /* * If the pidfile or restart option is specified the daemon * executes the command in a forked process and wait on child * exit to remove the pidfile or restart the command. Normally * we don't want the monitoring daemon to be terminated * leaving the running process and the stale pidfile, so we * catch SIGTERM and forward it to the children expecting to * get SIGCHLD eventually. */ pid = -1; if (pidfile != NULL || ppidfile != NULL || restart) { /* * Restore default action for SIGTERM in case the * parent process decided to ignore it. */ if (signal(SIGTERM, SIG_DFL) == SIG_ERR) { warn("signal"); goto exit; } /* * Because SIGCHLD is ignored by default, setup dummy handler * for it, so we can mask it. */ if (signal(SIGCHLD, dummy_sighandler) == SIG_ERR) { warn("signal"); goto exit; } /* * Block interesting signals. */ sigemptyset(&mask); sigaddset(&mask, SIGTERM); sigaddset(&mask, SIGCHLD); if (sigprocmask(SIG_SETMASK, &mask, &oldmask) == -1) { warn("sigprocmask"); goto exit; } /* * Try to protect against pageout kill. Ignore the * error, madvise(2) will fail only if a process does * not have superuser privileges. */ (void)madvise(NULL, 0, MADV_PROTECT); restart: /* * Spawn a child to exec the command, so in the parent * we could wait for it to exit and remove pidfile. */ pid = fork(); if (pid == -1) { warn("fork"); goto exit; } } if (pid <= 0) { if (pid == 0) { /* Restore old sigmask in the child. */ if (sigprocmask(SIG_SETMASK, &oldmask, NULL) == -1) err(1, "sigprocmask"); } /* Now that we are the child, write out the pid. */ pidfile_write(pfh); if (user != NULL) restrict_process(user); execvp(argv[0], argv); /* * execvp() failed -- report the error. The child is * now running, so the exit status doesn't matter. */ err(1, "%s", argv[0]); } setproctitle("%s[%d]", argv[0], pid); if (wait_child(pid, &mask) == 0 && restart) { sleep(1); goto restart; } exit: pidfile_remove(pfh); pidfile_remove(ppfh); exit(1); /* If daemon(3) succeeded exit status does not matter. */ } static void dummy_sighandler(int sig __unused) { /* Nothing to do. */ } static void restrict_process(const char *user) { struct passwd *pw = NULL; pw = getpwnam(user); if (pw == NULL) errx(1, "unknown user: %s", user); if (setusercontext(NULL, pw, pw->pw_uid, LOGIN_SETALL) != 0) errx(1, "failed to set user environment"); } static int wait_child(pid_t pid, sigset_t *mask) { int terminate, signo; terminate = 0; for (;;) { if (sigwait(mask, &signo) == -1) { warn("sigwaitinfo"); return (-1); } switch (signo) { case SIGCHLD: if (waitpid(pid, NULL, WNOHANG) == -1) { warn("waitpid"); return (-1); } return (terminate); case SIGTERM: terminate = 1; if (kill(pid, signo) == -1) { warn("kill"); return (-1); } continue; default: warnx("sigwaitinfo: invalid signal: %d", signo); return (-1); } } } static void usage(void) { (void)fprintf(stderr, "usage: daemon [-cfr] [-p child_pidfile] [-P supervisor_pidfile] " "[-u user]\n command arguments ...\n"); exit(1); }