/* pidfile.c * * Functions to assist in the writing and removing of pidfiles. * * Russ Dill <Russ.Dill@asu.edu> September 2001 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>#include <stdio.h>#include <stdlib.h>#include "common.h"#include "pidfile.h"static char *saved_pidfile;static void pidfile_delete(void){	if (saved_pidfile) unlink(saved_pidfile);}int pidfile_acquire(const char *pidfile){	int pid_fd;	if (!pidfile) return -1;	pid_fd = open(pidfile, O_CREAT | O_WRONLY, 0644);	if (pid_fd < 0) {		LOG(LOG_ERR, "Unable to open pidfile %s: %m\n", pidfile);	} else {		lockf(pid_fd, F_LOCK, 0);		if (!saved_pidfile)			atexit(pidfile_delete);		saved_pidfile = (char *) pidfile;	}	return pid_fd;}void pidfile_write_release(int pid_fd){	FILE *out;	if (pid_fd < 0) return;	if ((out = fdopen(pid_fd, "w")) != NULL) {		fprintf(out, "%d\n", getpid());		fclose(out);	}	lockf(pid_fd, F_UNLCK, 0);	close(pid_fd);}