NetBSD/lib/libutil/pidfile.c

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/* $NetBSD: pidfile.c,v 1.6 2001/10/20 09:20:28 taca 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 and Matthias Scheler.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 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/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: pidfile.c,v 1.6 2001/10/20 09:20:28 taca Exp $");
#endif
#include <sys/param.h>
#include <paths.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <util.h>
static int pidfile_atexit_done;
static pid_t pidfile_pid;
static char *pidfile_basename;
static char *pidfile_path;
static void pidfile_cleanup(void);
void
pidfile(const char *basename)
{
FILE *f;
/*
* Register handler which will remove the pidfile later.
*/
if (!pidfile_atexit_done) {
if (atexit(pidfile_cleanup) < 0)
return;
pidfile_atexit_done = 1;
}
if (basename == NULL)
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basename = getprogname();
/*
* If pidfile has already been created for the supplied basename
* we don't need to create a pidfile again.
*/
if (pidfile_path != NULL) {
if (strcmp(pidfile_basename, basename) == 0)
return;
/*
* Remove existing pidfile if it was created by this process.
*/
pidfile_cleanup();
free(pidfile_path);
pidfile_path = NULL;
free(pidfile_basename);
pidfile_basename = NULL;
}
pidfile_pid = getpid();
pidfile_basename = strdup(basename);
if (pidfile_basename == NULL)
return;
/* _PATH_VARRUN includes trailing / */
(void) asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename);
if (pidfile_path == NULL) {
free(pidfile_basename);
pidfile_basename = NULL;
return;
}
if ((f = fopen(pidfile_path, "w")) == NULL) {
free(pidfile_path);
pidfile_path = NULL;
free(pidfile_basename);
pidfile_basename = NULL;
return;
}
(void) fprintf(f, "%d\n", pidfile_pid);
(void) fclose(f);
}
static void
pidfile_cleanup(void)
{
/* Only remove the pidfile if it was created by this process. */
if ((pidfile_path != NULL) && (pidfile_pid == getpid()))
(void) unlink(pidfile_path);
}