IABSD.fr/src/lib/libutil/pidfile.c

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• Author : schwarze
  Date : 2019-06-28 14:20:40
  Hash : 80e53f5b
  Message : Actually, the C standard only guarantees that atexit(3) returns non-zero on error, so tweak previous to test "atexit(...) != 0" for portability. "OK ok ok sorry backwards" deraadt@

• lib/libutil/pidfile.c

• /*	$OpenBSD: pidfile.c,v 1.14 2019/06/28 14:20:40 schwarze Exp $	*/
  /*	$NetBSD: pidfile.c,v 1.4 2001/02/19 22:43:42 cgd Exp $	*/
  
  /*-
   * Copyright (c) 1999 The NetBSD Foundation, Inc.
   * All rights reserved.
   *
   * This code is derived from software contributed to The NetBSD Foundation
   * by Jason R. Thorpe.
   *
   * 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.
   *
   * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   * ``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 THE FOUNDATION OR CONTRIBUTORS
   * 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.
   */
  
  #include <sys/types.h>
  #include <errno.h>
  #include <paths.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <util.h>
  
  static char *pidfile_path;
  static pid_t pidfile_pid;
  
  static void pidfile_cleanup(void);
  
  extern char *__progname;
  
  int
  pidfile(const char *basename)
  {
  	int save_errno;
  	pid_t pid;
  	FILE *f;
  
  	if (basename == NULL)
  		basename = __progname;
  
  	free(pidfile_path);
  	pidfile_path = NULL;
  
  	/* _PATH_VARRUN includes trailing / */
  	if (asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename) == -1)
  		return (-1);
  
  	if ((f = fopen(pidfile_path, "w")) == NULL) {
  		save_errno = errno;
  		free(pidfile_path);
  		pidfile_path = NULL;
  		errno = save_errno;
  		return (-1);
  	}
  
  	pid = getpid();
  	if (fprintf(f, "%ld\n", (long)pid) <= 0 || fflush(f) != 0) {
  		save_errno = errno;
  		(void) fclose(f);
  		(void) unlink(pidfile_path);
  		free(pidfile_path);
  		pidfile_path = NULL;
  		errno = save_errno;
  		return (-1);
  	}
  	(void) fclose(f);
  
  	pidfile_pid = pid;
  	if (atexit(pidfile_cleanup) != 0) {
  		save_errno = errno;
  		(void) unlink(pidfile_path);
  		free(pidfile_path);
  		pidfile_path = NULL;
  		pidfile_pid = 0;
  		errno = save_errno;
  		return (-1);
  	}
  
  	return (0);
  }
  
  static void
  pidfile_cleanup(void)
  {
  
  	if (pidfile_path != NULL && pidfile_pid == getpid())
  		(void) unlink(pidfile_path);
  }