1 /* $NetBSD: pidfile.c,v 1.6 2001/10/20 09:20:28 taca Exp $ */ 2 /* $DragonFly: src/lib/libutil/pidfile.c,v 1.1 2004/09/22 05:06:57 joerg Exp $ */ 3 4 /*- 5 * Copyright (c) 1999 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Jason R. Thorpe and Matthias Scheler. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 #include <sys/param.h> 41 #include <libutil.h> 42 #include <paths.h> 43 #include <stdlib.h> 44 #include <stdio.h> 45 #include <string.h> 46 #include <unistd.h> 47 48 static int pidfile_atexit_done; 49 static pid_t pidfile_pid; 50 static char *pidfile_basename; 51 static char *pidfile_path; 52 53 static void pidfile_cleanup(void); 54 55 int 56 pidfile(const char *basename) 57 { 58 FILE *f; 59 60 /* 61 * Register handler which will remove the pidfile later. 62 */ 63 if (!pidfile_atexit_done) { 64 if (atexit(pidfile_cleanup) < 0) 65 return -1; 66 pidfile_atexit_done = 1; 67 } 68 69 if (basename == NULL) 70 basename = getprogname(); 71 72 /* 73 * If pidfile has already been created for the supplied basename 74 * we don't need to create a pidfile again. 75 */ 76 if (pidfile_path != NULL) { 77 if (strcmp(pidfile_basename, basename) == 0) 78 return 0; 79 /* 80 * Remove existing pidfile if it was created by this process. 81 */ 82 pidfile_cleanup(); 83 84 free(pidfile_path); 85 pidfile_path = NULL; 86 free(pidfile_basename); 87 pidfile_basename = NULL; 88 } 89 90 pidfile_pid = getpid(); 91 92 pidfile_basename = strdup(basename); 93 if (pidfile_basename == NULL) 94 return -1; 95 96 /* _PATH_VARRUN includes trailing / */ 97 asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename); 98 if (pidfile_path == NULL) { 99 free(pidfile_basename); 100 pidfile_basename = NULL; 101 return -1; 102 } 103 104 if ((f = fopen(pidfile_path, "w")) == NULL) { 105 free(pidfile_path); 106 pidfile_path = NULL; 107 free(pidfile_basename); 108 pidfile_basename = NULL; 109 return -1; 110 } 111 112 fprintf(f, "%d\n", pidfile_pid); 113 fclose(f); 114 return 0; 115 } 116 117 static void 118 pidfile_cleanup(void) 119 { 120 /* Only remove the pidfile if it was created by this process. */ 121 if ((pidfile_path != NULL) && (pidfile_pid == getpid())) 122 unlink(pidfile_path); 123 } 124