9da0ef1316
2. Write the supervisor pid before the restart loop, so we don't uselessly rewrite it after every child restart. 3. Remove duplicate ppfh and pfh initialization. Approved by: re (glebius) MFC after: 2 weeks
277 lines
6.7 KiB
C
277 lines
6.7 KiB
C
/*-
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* Copyright (c) 1999 Berkeley Software Design, Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Berkeley Software Design Inc's name may not be used to endorse or
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* promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* From BSDI: daemon.c,v 1.2 1996/08/15 01:11:09 jch Exp
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/mman.h>
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#include <sys/wait.h>
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#include <err.h>
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#include <errno.h>
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#include <libutil.h>
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#include <login_cap.h>
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#include <pwd.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 <unistd.h>
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static void dummy_sighandler(int);
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static void restrict_process(const char *);
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static int wait_child(pid_t pid, sigset_t *mask);
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static void usage(void);
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int
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main(int argc, char *argv[])
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{
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struct pidfh *ppfh, *pfh;
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sigset_t mask, oldmask;
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int ch, nochdir, noclose, restart, serrno;
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const char *pidfile, *ppidfile, *user;
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pid_t otherpid, pid;
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nochdir = noclose = 1;
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restart = 0;
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ppidfile = pidfile = user = NULL;
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while ((ch = getopt(argc, argv, "cfp:P:ru:")) != -1) {
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switch (ch) {
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case 'c':
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nochdir = 0;
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break;
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case 'f':
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noclose = 0;
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break;
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case 'p':
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pidfile = optarg;
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break;
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case 'P':
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ppidfile = optarg;
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break;
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case 'r':
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restart = 1;
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break;
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case 'u':
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user = optarg;
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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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argc -= optind;
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argv += optind;
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if (argc == 0)
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usage();
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ppfh = pfh = NULL;
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/*
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* Try to open the pidfile before calling daemon(3),
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* to be able to report the error intelligently
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*/
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if (pidfile != NULL) {
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pfh = pidfile_open(pidfile, 0600, &otherpid);
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if (pfh == NULL) {
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if (errno == EEXIST) {
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errx(3, "process already running, pid: %d",
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otherpid);
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}
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err(2, "pidfile ``%s''", pidfile);
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}
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}
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/* Do the same for actual daemon process. */
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if (ppidfile != NULL) {
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ppfh = pidfile_open(ppidfile, 0600, &otherpid);
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if (ppfh == NULL) {
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serrno = errno;
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pidfile_remove(pfh);
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errno = serrno;
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if (errno == EEXIST) {
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errx(3, "process already running, pid: %d",
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otherpid);
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}
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err(2, "ppidfile ``%s''", ppidfile);
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}
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}
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if (daemon(nochdir, noclose) == -1) {
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warn("daemon");
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goto exit;
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}
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/* Write out parent pidfile if needed. */
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pidfile_write(ppfh);
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/*
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* If the pidfile or restart option is specified the daemon
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* executes the command in a forked process and wait on child
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* exit to remove the pidfile or restart the command. Normally
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* we don't want the monitoring daemon to be terminated
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* leaving the running process and the stale pidfile, so we
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* catch SIGTERM and forward it to the children expecting to
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* get SIGCHLD eventually.
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*/
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pid = -1;
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if (pidfile != NULL || restart) {
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/*
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* Restore default action for SIGTERM in case the
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* parent process decided to ignore it.
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*/
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if (signal(SIGTERM, SIG_DFL) == SIG_ERR) {
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warn("signal");
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goto exit;
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}
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/*
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* Because SIGCHLD is ignored by default, setup dummy handler
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* for it, so we can mask it.
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*/
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if (signal(SIGCHLD, dummy_sighandler) == SIG_ERR) {
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warn("signal");
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goto exit;
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}
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/*
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* Block interesting signals.
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*/
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sigemptyset(&mask);
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sigaddset(&mask, SIGTERM);
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sigaddset(&mask, SIGCHLD);
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if (sigprocmask(SIG_SETMASK, &mask, &oldmask) == -1) {
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warn("sigprocmask");
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goto exit;
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}
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/*
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* Try to protect against pageout kill. Ignore the
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* error, madvise(2) will fail only if a process does
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* not have superuser privileges.
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*/
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(void)madvise(NULL, 0, MADV_PROTECT);
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restart:
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/*
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* Spawn a child to exec the command, so in the parent
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* we could wait for it to exit and remove pidfile.
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*/
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pid = fork();
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if (pid == -1) {
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warn("fork");
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goto exit;
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}
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}
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if (pid <= 0) {
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if (pid == 0) {
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/* Restore old sigmask in the child. */
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if (sigprocmask(SIG_SETMASK, &oldmask, NULL) == -1)
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err(1, "sigprocmask");
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}
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/* Now that we are the child, write out the pid. */
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pidfile_write(pfh);
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if (user != NULL)
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restrict_process(user);
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execvp(argv[0], argv);
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/*
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* execvp() failed -- report the error. The child is
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* now running, so the exit status doesn't matter.
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*/
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err(1, "%s", argv[0]);
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}
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setproctitle("%s[%d]", argv[0], pid);
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if (wait_child(pid, &mask) == 0 && restart) {
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sleep(1);
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goto restart;
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}
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exit:
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pidfile_remove(pfh);
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pidfile_remove(ppfh);
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exit(1); /* If daemon(3) succeeded exit status does not matter. */
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}
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static void
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dummy_sighandler(int sig __unused)
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{
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/* Nothing to do. */
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}
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static void
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restrict_process(const char *user)
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{
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struct passwd *pw = NULL;
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pw = getpwnam(user);
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if (pw == NULL)
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errx(1, "unknown user: %s", user);
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if (setusercontext(NULL, pw, pw->pw_uid, LOGIN_SETALL) != 0)
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errx(1, "failed to set user environment");
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}
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static int
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wait_child(pid_t pid, sigset_t *mask)
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{
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int terminate, signo;
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terminate = 0;
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for (;;) {
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if (sigwait(mask, &signo) == -1) {
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warn("sigwaitinfo");
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return (-1);
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}
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switch (signo) {
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case SIGCHLD:
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if (waitpid(pid, NULL, WNOHANG) == -1) {
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warn("waitpid");
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return (-1);
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}
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return (terminate);
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case SIGTERM:
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terminate = 1;
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if (kill(pid, signo) == -1) {
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warn("kill");
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return (-1);
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}
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continue;
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default:
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warnx("sigwaitinfo: invalid signal: %d", signo);
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return (-1);
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}
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}
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}
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static void
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usage(void)
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{
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(void)fprintf(stderr,
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"usage: daemon [-cfr] [-p child_pidfile] [-P supervisor_pidfile] "
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"[-u user]\n command arguments ...\n");
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exit(1);
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}
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