1 /* $NetBSD: pidfile.c,v 1.7 2002/05/22 07:31:45 itojun 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #if defined(LIBC_SCCS) && !defined(lint) 41 __RCSID("$NetBSD: pidfile.c,v 1.7 2002/05/22 07:31:45 itojun Exp $"); 42 #endif 43 44 #include <sys/param.h> 45 #include <paths.h> 46 #include <stdlib.h> 47 #include <stdio.h> 48 #include <string.h> 49 #include <unistd.h> 50 #include <util.h> 51 52 static int pidfile_atexit_done; 53 static pid_t pidfile_pid; 54 static char *pidfile_basename; 55 static char *pidfile_path; 56 57 static void pidfile_cleanup(void); 58 59 int 60 pidfile(const char *basename) 61 { 62 FILE *f; 63 64 /* 65 * Register handler which will remove the pidfile later. 66 */ 67 if (!pidfile_atexit_done) { 68 if (atexit(pidfile_cleanup) < 0) 69 return -1; 70 pidfile_atexit_done = 1; 71 } 72 73 if (basename == NULL) 74 basename = getprogname(); 75 76 /* 77 * If pidfile has already been created for the supplied basename 78 * we don't need to create a pidfile again. 79 */ 80 if (pidfile_path != NULL) { 81 if (strcmp(pidfile_basename, basename) == 0) 82 return 0; 83 /* 84 * Remove existing pidfile if it was created by this process. 85 */ 86 pidfile_cleanup(); 87 88 free(pidfile_path); 89 pidfile_path = NULL; 90 free(pidfile_basename); 91 pidfile_basename = NULL; 92 } 93 94 pidfile_pid = getpid(); 95 96 pidfile_basename = strdup(basename); 97 if (pidfile_basename == NULL) 98 return -1; 99 100 /* _PATH_VARRUN includes trailing / */ 101 (void) asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename); 102 if (pidfile_path == NULL) { 103 free(pidfile_basename); 104 pidfile_basename = NULL; 105 return -1; 106 } 107 108 if ((f = fopen(pidfile_path, "w")) == NULL) { 109 free(pidfile_path); 110 pidfile_path = NULL; 111 free(pidfile_basename); 112 pidfile_basename = NULL; 113 return -1; 114 } 115 116 (void) fprintf(f, "%d\n", pidfile_pid); 117 (void) fclose(f); 118 return 0; 119 } 120 121 static void 122 pidfile_cleanup(void) 123 { 124 /* Only remove the pidfile if it was created by this process. */ 125 if ((pidfile_path != NULL) && (pidfile_pid == getpid())) 126 (void) unlink(pidfile_path); 127 } 128