+/*-
+ * 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 <sys/cdefs.h>
+__FBSDID("$FreeBSD: src/usr.sbin/daemon/daemon.c,v 1.8 2007/04/19 16:43:30 peter Exp $");
+
+#include <sys/param.h>
+
+#include <err.h>
+#include <errno.h>
+#include <pwd.h>
+#include <libutil.h>
+#include <login_cap.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static void restrict_process(const char *);
+static void usage(void);
+
+int
+main(int argc, char *argv[])
+{
+ struct pidfh *pfh = NULL;
+ int ch, nochdir, noclose, errcode;
+ const char *pidfile, *user;
+ pid_t otherpid;
+
+ nochdir = noclose = 1;
+ pidfile = user = NULL;
+ while ((ch = getopt(argc, argv, "-cfp:u:")) != -1) {
+ switch (ch) {
+ case 'c':
+ nochdir = 0;
+ break;
+ case 'f':
+ noclose = 0;
+ break;
+ case 'p':
+ pidfile = optarg;
+ break;
+ case 'u':
+ user = optarg;
+ break;
+ default:
+ usage();
+ }
+ }
+ argc -= optind;
+ argv += optind;
+
+ if (argc == 0)
+ usage();
+
+ if (user != NULL)
+ restrict_process(user);
+
+ /*
+ * Try to open the pidfile before calling daemon(3),
+ * to be able to report the error intelligently
+ */
+ if (pidfile) {
+ 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);
+ }
+ }
+
+ if (daemon(nochdir, noclose) == -1)
+ err(1, NULL);
+
+ /* Now that we are the child, write out the pid */
+ if (pidfile)
+ pidfile_write(pfh);
+
+ execvp(argv[0], argv);
+
+ /*
+ * execvp() failed -- unlink pidfile if any, and
+ * report the error
+ */
+ errcode = errno; /* Preserve errcode -- unlink may reset it */
+ if (pidfile)
+ pidfile_remove(pfh);
+
+ /* The child is now running, so the exit status doesn't matter. */
+ errc(1, errcode, "%s", argv[0]);
+}
+
+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 void
+usage(void)
+{
+ (void)fprintf(stderr,
+ "usage: daemon [-cf] [-p pidfile] [-u user] command "
+ "arguments ...\n");
+ exit(1);
+}