1 /* $NetBSD: pidfile.c,v 1.8 2008/04/28 20:23:03 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 1999 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe and Matthias Scheler. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: pidfile.c,v 1.8 2008/04/28 20:23:03 martin Exp $"); 35 #endif 36 37 #include <sys/param.h> 38 #include <paths.h> 39 #include <stdlib.h> 40 #include <stdio.h> 41 #include <string.h> 42 #include <unistd.h> 43 #include <util.h> 44 45 static int pidfile_atexit_done; 46 static pid_t pidfile_pid; 47 static char *pidfile_basename; 48 static char *pidfile_path; 49 50 static void pidfile_cleanup(void); 51 52 int 53 pidfile(const char *basename) 54 { 55 FILE *f; 56 57 /* 58 * Register handler which will remove the pidfile later. 59 */ 60 if (!pidfile_atexit_done) { 61 if (atexit(pidfile_cleanup) < 0) 62 return -1; 63 pidfile_atexit_done = 1; 64 } 65 66 if (basename == NULL) 67 basename = getprogname(); 68 69 /* 70 * If pidfile has already been created for the supplied basename 71 * we don't need to create a pidfile again. 72 */ 73 if (pidfile_path != NULL) { 74 if (strcmp(pidfile_basename, basename) == 0) 75 return 0; 76 /* 77 * Remove existing pidfile if it was created by this process. 78 */ 79 pidfile_cleanup(); 80 81 free(pidfile_path); 82 pidfile_path = NULL; 83 free(pidfile_basename); 84 pidfile_basename = NULL; 85 } 86 87 pidfile_pid = getpid(); 88 89 pidfile_basename = strdup(basename); 90 if (pidfile_basename == NULL) 91 return -1; 92 93 /* _PATH_VARRUN includes trailing / */ 94 (void) asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename); 95 if (pidfile_path == NULL) { 96 free(pidfile_basename); 97 pidfile_basename = NULL; 98 return -1; 99 } 100 101 if ((f = fopen(pidfile_path, "w")) == NULL) { 102 free(pidfile_path); 103 pidfile_path = NULL; 104 free(pidfile_basename); 105 pidfile_basename = NULL; 106 return -1; 107 } 108 109 (void) fprintf(f, "%d\n", pidfile_pid); 110 (void) fclose(f); 111 return 0; 112 } 113 114 static void 115 pidfile_cleanup(void) 116 { 117 /* Only remove the pidfile if it was created by this process. */ 118 if ((pidfile_path != NULL) && (pidfile_pid == getpid())) 119 (void) unlink(pidfile_path); 120 } 121