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    1: /*	$OpenBSD: pidfile.c,v 1.8 2008/06/26 05:42:05 ray Exp $	*/
    2: /*	$NetBSD: pidfile.c,v 1.4 2001/02/19 22:43:42 cgd 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.
   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:  *
   20:  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   21:  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   22:  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   23:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   24:  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   25:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   26:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   27:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   28:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   29:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   30:  * POSSIBILITY OF SUCH DAMAGE.
   31:  */
   32: 
   33: #include <sys/param.h>
   34: #include <errno.h>
   35: #include <paths.h>
   36: #include <stdio.h>
   37: #include <stdlib.h>
   38: #include <unistd.h>
   39: 
   40: static char *pidfile_path;
   41: static pid_t pidfile_pid;
   42: 
   43: static void pidfile_cleanup(void);
   44: 
   45: extern char *__progname;
   46: 
   47: int
   48: pidfile(const char *basename)
   49: {
   50: 	int save_errno, result;
   51: 	pid_t pid;
   52: 	FILE *f;
   53: 
   54: 	if (basename == NULL)
   55: 		basename = __progname;
   56: 
   57: 	if (pidfile_path != NULL) {
   58: 		free(pidfile_path);
   59: 		pidfile_path = NULL;
   60: 	}
   61: 
   62: 	/* _PATH_VARRUN includes trailing / */
   63: 	result = asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename);
   64: 	if (result == -1 || pidfile_path == NULL)
   65: 		return (-1);
   66: 
   67: 	if ((f = fopen(pidfile_path, "w")) == NULL) {
   68: 		save_errno = errno;
   69: 		free(pidfile_path);
   70: 		pidfile_path = NULL;
   71: 		errno = save_errno;
   72: 		return (-1);
   73: 	}
   74: 
   75: 	pid = getpid();
   76: 	if (fprintf(f, "%ld\n", (long)pid) <= 0 || fclose(f) != 0) {
   77: 		save_errno = errno;
   78: 		(void) unlink(pidfile_path);
   79: 		free(pidfile_path);
   80: 		pidfile_path = NULL;
   81: 		errno = save_errno;
   82: 		return (-1);
   83: 	}
   84: 
   85: 	pidfile_pid = pid;
   86: 	if (atexit(pidfile_cleanup) < 0) {
   87: 		save_errno = errno;
   88: 		(void) unlink(pidfile_path);
   89: 		free(pidfile_path);
   90: 		pidfile_path = NULL;
   91: 		pidfile_pid = 0;
   92: 		errno = save_errno;
   93: 		return (-1);
   94: 	}
   95: 
   96: 	return (0);
   97: }
   98: 
   99: static void
  100: pidfile_cleanup(void)
  101: {
  102: 
  103: 	if (pidfile_path != NULL && pidfile_pid == getpid())
  104: 		(void) unlink(pidfile_path);
  105: }