usr.sbin/daemon/daemon.c

   1 /*-
   2  * Copyright (c) 1999 Berkeley Software Design, Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. Berkeley Software Design Inc's name may not be used to endorse or
  13  *    promote products derived from this software without specific prior
  14  *    written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  *      From BSDI: daemon.c,v 1.2 1996/08/15 01:11:09 jch Exp
  29  * $FreeBSD: src/usr.sbin/daemon/daemon.c,v 1.1.2.1 2002/08/28 17:25:54 sheldonh Exp $
  30  * $DragonFly: src/usr.sbin/daemon/daemon.c,v 1.4 2004/12/21 23:30:57 liamfoy Exp $
  31  */
  32
  33 #include <sys/types.h>
  34
  35 #include <err.h>
  36 #include <errno.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <unistd.h>
  40
  41 static void usage(void);
  42
  43 int
  44 main(int argc, char *argv[])
  45 {
  46         int ch, nochdir, noclose, errcode;
  47         FILE *pidf;
  48         const char *pidfile;
  49
  50         nochdir = noclose = 1;
  51         pidfile = NULL;
  52         pidf = 0;
  53         while ((ch = getopt(argc, argv, "cfp:")) != -1) {
  54                 switch (ch) {
  55                 case 'c':
  56                         nochdir = 0;
  57                         break;
  58                 case 'f':
  59                         noclose = 0;
  60                         break;
  61                 case 'p':
  62                         pidfile = optarg;
  63                 case '?':
  64                 default:
  65                         usage();
  66                 }
  67         }
  68         argc -= optind;
  69         argv += optind;
  70
  71         if (argc == 0)
  72                 usage();
  73
  74         /*
  75          * Try to open the pidfile before calling daemon(3),
  76          * to be able to report the error intelligently
  77          */
  78         if (pidfile) {
  79                 pidf = fopen(pidfile, "w");
  80                 if (pidf == NULL)
  81                         err(1, "pidfile ``%s''", pidfile);
  82         }
  83
  84         if (daemon(nochdir, noclose) == -1)
  85                 err(1, "daemon failed");
  86
  87         /* Now that we are the child, write out the pid */
  88         if (pidfile) {
  89                 fprintf(pidf, "%ld\n", (long)getpid());
  90                 fclose(pidf);
  91         }
  92
  93         execvp(argv[0], argv);
  94
  95         /*
  96          * execvp() failed -- unlink pidfile if any, and
  97          * report the error
  98          */
  99         errcode = errno; /* Preserve errcode -- unlink may reset it */
 100         if (pidfile)
 101                 unlink(pidfile);
 102
 103         /* The child is now running, so the exit status doesn't matter. */
 104         errc(1, errcode, "%s", argv[0]);
 105 }
 106
 107 static void
 108 usage(void)
 109 {
 110         fprintf(stderr, "usage: daemon [-cf] [-p pidfile] command arguments ...\n");
 111         exit(1);
 112 }