lib/libutil/pidfile.c

   1 /*      $NetBSD: pidfile.c,v 1.6 2001/10/20 09:20:28 taca Exp $ */
   2 /*      $DragonFly: src/lib/libutil/pidfile.c,v 1.2 2005/03/04 04:31:11 cpressey Exp $ */
   3
   4 /*-
   5  * Copyright (c) 1999 The NetBSD Foundation, Inc.
   6  * All rights reserved.
   7  *
   8  * This code is derived from software contributed to The NetBSD Foundation
   9  * by Jason R. Thorpe and Matthias Scheler.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. All advertising materials mentioning features or use of this software
  20  *    must display the following acknowledgement:
  21  *        This product includes software developed by the NetBSD
  22  *        Foundation, Inc. and its contributors.
  23  * 4. Neither the name of The NetBSD Foundation nor the names of its
  24  *    contributors may be used to endorse or promote products derived
  25  *    from this software without specific prior written permission.
  26  *
  27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  37  * POSSIBILITY OF SUCH DAMAGE.
  38  */
  39
  40 #include <sys/param.h>
  41
  42 #include <paths.h>
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <unistd.h>
  47
  48 #include "libutil.h"
  49
  50 static int   pidfile_atexit_done;
  51 static pid_t pidfile_pid;
  52 static char *pidfile_basename;
  53 static char *pidfile_path;
  54
  55 static void pidfile_cleanup(void);
  56
  57 int
  58 pidfile(const char *basename)
  59 {
  60         FILE *f;
  61
  62         /*
  63          * Register handler which will remove the pidfile later.
  64          */
  65         if (!pidfile_atexit_done) {
  66                 if (atexit(pidfile_cleanup) < 0)
  67                         return -1;
  68                 pidfile_atexit_done = 1;
  69         }
  70
  71         if (basename == NULL)
  72                 basename = getprogname();
  73
  74         /*
  75          * If pidfile has already been created for the supplied basename
  76          * we don't need to create a pidfile again.
  77          */
  78         if (pidfile_path != NULL) {
  79                 if (strcmp(pidfile_basename, basename) == 0)
  80                         return 0;
  81                 /*
  82                  * Remove existing pidfile if it was created by this process.
  83                  */
  84                 pidfile_cleanup();
  85
  86                 free(pidfile_path);
  87                 pidfile_path = NULL;
  88                 free(pidfile_basename);
  89                 pidfile_basename = NULL;
  90         }
  91
  92         pidfile_pid = getpid();
  93
  94         pidfile_basename = strdup(basename);
  95         if (pidfile_basename == NULL)
  96                 return -1;
  97
  98         /* _PATH_VARRUN includes trailing / */
  99         asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename);
 100         if (pidfile_path == NULL) {
 101                 free(pidfile_basename);
 102                 pidfile_basename = NULL;
 103                 return -1;
 104         }
 105
 106         if ((f = fopen(pidfile_path, "w")) == NULL) {
 107                 free(pidfile_path);
 108                 pidfile_path = NULL;
 109                 free(pidfile_basename);
 110                 pidfile_basename = NULL;
 111                 return -1;
 112         }
 113
 114         fprintf(f, "%d\n", pidfile_pid);
 115         fclose(f);
 116         return 0;
 117 }
 118
 119 static void
 120 pidfile_cleanup(void)
 121 {
 122         /* Only remove the pidfile if it was created by this process. */
 123         if ((pidfile_path != NULL) && (pidfile_pid == getpid()))
 124                 unlink(pidfile_path);
 125 }