Differential D5912 Diff 15080 contrib/blacklist/port/pidfile.c

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contrib/blacklist/port/pidfile.c

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				/* $NetBSD: pidfile.c,v 1.2 2016/04/05 12:28:57 christos 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, Matthias Scheler and Julio Merino.
				*
				* 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.
				*/
				#ifdef HAVE_CONFIG_H
				#include "config.h"
				#endif

				#include <sys/cdefs.h>
				#if defined(LIBC_SCCS) && !defined(lint)
				__RCSID("$NetBSD: pidfile.c,v 1.2 2016/04/05 12:28:57 christos Exp $");
				#endif

				#include <sys/param.h>

				#include <paths.h>
				#include <stdbool.h>
				#include <stdlib.h>
				#include <stdio.h>
				#include <string.h>
				#include <unistd.h>
				#ifdef HAVE_LIBUTIL_H
				#include <libutil.h>
				#endif
				#ifdef HAVE_UTIL_H
				#include <util.h>
				#endif

				static pid_t pidfile_pid;
				static char *pidfile_path;

				/* Deletes an existent pidfile iff it was created by this process. */
				static void
				pidfile_cleanup(void)
				{

				if ((pidfile_path != NULL) && (pidfile_pid == getpid()))
				(void) unlink(pidfile_path);
				}

				/* Registers an atexit(3) handler to delete the pidfile we have generated.
				* We only register the handler when we create a pidfile, so we can assume
				* that the pidfile exists.
				*
				* Returns 0 on success or -1 if the handler could not be registered. */
				static int
				register_atexit_handler(void)
				{
				static bool done = false;

				if (!done) {
				if (atexit(pidfile_cleanup) < 0)
				return -1;
				done = true;
				}

				return 0;
				}

				/* Given a new pidfile name in 'path', deletes any previously-created pidfile
				* if the previous file differs to the new one.
				*
				* If a previous file is deleted, returns 1, which means that a new pidfile
				* must be created. Otherwise, this returns 0, which means that the existing
				* file does not need to be touched. */
				static int
				cleanup_old_pidfile(const char* path)
				{
				if (pidfile_path != NULL) {
				if (strcmp(pidfile_path, path) != 0) {
				pidfile_cleanup();

				free(pidfile_path);
				pidfile_path = NULL;

				return 1;
				} else
				return 0;
				} else
				return 1;
				}

				/* Constructs a name for a pidfile in the default location (/var/run). If
				* 'basename' is NULL, uses the name of the current program for the name of
				* the pidfile.
				*
				* Returns a pointer to a dynamically-allocatd string containing the absolute
				* path to the pidfile; NULL on failure. */
				static char *
				generate_varrun_path(const char *bname)
				{
				char *path;

				if (bname == NULL)
				bname = getprogname();

				/* _PATH_VARRUN includes trailing / */
				if (asprintf(&path, "%s%s.pid", _PATH_VARRUN, bname) == -1)
				return NULL;
				return path;
				}

				/* Creates a pidfile with the provided name. The new pidfile is "registered"
				* in the global variables pidfile_path and pidfile_pid so that any further
				* call to pidfile(3) can check if we are recreating the same file or a new
				* one.
				*
				* Returns 0 on success or -1 if there is any error. */
				static int
				create_pidfile(const char* path)
				{
				FILE *f;

				if (register_atexit_handler() == -1)
				return -1;

				if (cleanup_old_pidfile(path) == 0)
				return 0;

				pidfile_path = strdup(path);
				if (pidfile_path == NULL)
				return -1;

				if ((f = fopen(path, "w")) == NULL) {
				free(pidfile_path);
				pidfile_path = NULL;
				return -1;
				}

				pidfile_pid = getpid();

				(void) fprintf(f, "%d\n", pidfile_pid);
				(void) fclose(f);

				return 0;
				}

				int
				pidfile(const char *path)
				{

				if (path == NULL \|\| strchr(path, '/') == NULL) {
				char *default_path;

				if ((default_path = generate_varrun_path(path)) == NULL)
				return -1;

				if (create_pidfile(default_path) == -1) {
				free(default_path);
				return -1;
				}

				free(default_path);
				return 0;
				} else
				return create_pidfile(path);
				}