1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)atexit.c 8.2 (Berkeley) 7/3/94 33 * $FreeBSD: src/lib/libc/stdlib/atexit.c,v 1.8 2007/01/09 00:28:09 imp Exp $ 34 * $DragonFly: src/lib/libc/stdlib/atexit.c,v 1.7 2006/08/03 16:40:46 swildner Exp $ 35 */ 36 37 #include "namespace.h" 38 #include <stddef.h> 39 #include <stdlib.h> 40 #include <unistd.h> 41 #include <pthread.h> 42 #include "atexit.h" 43 #include "un-namespace.h" 44 45 #include "libc_private.h" 46 47 #define ATEXIT_FN_EMPTY 0 48 #define ATEXIT_FN_STD 1 49 #define ATEXIT_FN_CXA 2 50 51 static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER; 52 53 #define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x) 54 #define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x) 55 56 struct atexit { 57 struct atexit *next; /* next in list */ 58 int ind; /* next index in this table */ 59 struct atexit_fn { 60 int fn_type; /* ATEXIT_? from above */ 61 union { 62 void (*std_func)(void); 63 void (*cxa_func)(void *); 64 } fn_ptr; /* function pointer */ 65 void *fn_arg; /* argument for CXA callback */ 66 void *fn_dso; /* shared module handle */ 67 } fns[ATEXIT_SIZE]; /* the table itself */ 68 }; 69 70 static struct atexit *__atexit; /* points to head of LIFO stack */ 71 72 /* 73 * Register the function described by 'fptr' to be called at application 74 * exit or owning shared object unload time. This is a helper function 75 * for atexit and __cxa_atexit. 76 */ 77 static int 78 atexit_register(struct atexit_fn *fptr) 79 { 80 static struct atexit __atexit0; /* one guaranteed table */ 81 struct atexit *p; 82 83 _MUTEX_LOCK(&atexit_mutex); 84 if ((p = __atexit) == NULL) 85 __atexit = p = &__atexit0; 86 else while (p->ind >= ATEXIT_SIZE) { 87 struct atexit *old__atexit; 88 old__atexit = __atexit; 89 _MUTEX_UNLOCK(&atexit_mutex); 90 if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) 91 return (-1); 92 _MUTEX_LOCK(&atexit_mutex); 93 if (old__atexit != __atexit) { 94 /* Lost race, retry operation */ 95 _MUTEX_UNLOCK(&atexit_mutex); 96 free(p); 97 _MUTEX_LOCK(&atexit_mutex); 98 p = __atexit; 99 continue; 100 } 101 p->ind = 0; 102 p->next = __atexit; 103 __atexit = p; 104 } 105 p->fns[p->ind++] = *fptr; 106 _MUTEX_UNLOCK(&atexit_mutex); 107 return (0); 108 } 109 110 /* 111 * Register a function to be performed at exit. 112 */ 113 int 114 atexit(void (*func)(void)) 115 { 116 struct atexit_fn fn; 117 int error; 118 119 fn.fn_type = ATEXIT_FN_STD; 120 fn.fn_ptr.std_func = func; 121 fn.fn_arg = NULL; 122 fn.fn_dso = NULL; 123 124 error = atexit_register(&fn); 125 return (error); 126 } 127 128 /* 129 * Register a function to be performed at exit or when an shared object 130 * with given dso handle is unloaded dynamically. 131 */ 132 int 133 __cxa_atexit(void (*func)(void *), void *arg, void *dso) 134 { 135 struct atexit_fn fn; 136 int error; 137 138 fn.fn_type = ATEXIT_FN_CXA; 139 fn.fn_ptr.cxa_func = func; 140 fn.fn_arg = arg; 141 fn.fn_dso = dso; 142 143 error = atexit_register(&fn); 144 return (error); 145 } 146 147 /* 148 * Call all handlers registered with __cxa_atexit for the shared 149 * object owning 'dso'. Note: if 'dso' is NULL, then all remaining 150 * handlers are called. 151 */ 152 void 153 __cxa_finalize(void *dso) 154 { 155 struct atexit *p; 156 struct atexit_fn fn; 157 int n; 158 159 _MUTEX_LOCK(&atexit_mutex); 160 for (p = __atexit; p; p = p->next) { 161 for (n = p->ind; --n >= 0;) { 162 if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) 163 continue; /* already been called */ 164 if (dso != NULL && dso != p->fns[n].fn_dso) 165 continue; /* wrong DSO */ 166 fn = p->fns[n]; 167 /* 168 Mark entry to indicate that this particular handler 169 has already been called. 170 */ 171 p->fns[n].fn_type = ATEXIT_FN_EMPTY; 172 _MUTEX_UNLOCK(&atexit_mutex); 173 174 /* Call the function of correct type. */ 175 if (fn.fn_type == ATEXIT_FN_CXA) 176 fn.fn_ptr.cxa_func(fn.fn_arg); 177 else if (fn.fn_type == ATEXIT_FN_STD) 178 fn.fn_ptr.std_func(); 179 _MUTEX_LOCK(&atexit_mutex); 180 } 181 } 182 _MUTEX_UNLOCK(&atexit_mutex); 183 } 184