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 * 3. 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: head/lib/libc/stdlib/atexit.c 211894 2010-08-27 19:57:17Z kib $ 34 */ 35 36 #include "namespace.h" 37 #include <link.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 #define _MUTEX_DESTROY(x) if (__isthreaded) _pthread_mutex_destroy(x) 56 57 struct atexit { 58 struct atexit *next; /* next in list */ 59 int ind; /* next index in this table */ 60 struct atexit_fn { 61 int fn_type; /* ATEXIT_? from above */ 62 union { 63 void (*std_func)(void); 64 void (*cxa_func)(void *); 65 } fn_ptr; /* function pointer */ 66 void *fn_arg; /* argument for CXA callback */ 67 void *fn_dso; /* shared module handle */ 68 } fns[ATEXIT_SIZE]; /* the table itself */ 69 }; 70 71 static struct atexit *__atexit; /* points to head of LIFO stack */ 72 73 /* 74 * Register the function described by 'fptr' to be called at application 75 * exit or owning shared object unload time. This is a helper function 76 * for atexit and __cxa_atexit. 77 */ 78 static int 79 atexit_register(struct atexit_fn *fptr) 80 { 81 static struct atexit __atexit0; /* one guaranteed table */ 82 struct atexit *p; 83 84 _MUTEX_LOCK(&atexit_mutex); 85 if ((p = __atexit) == NULL) 86 __atexit = p = &__atexit0; 87 else while (p->ind >= ATEXIT_SIZE) { 88 struct atexit *old__atexit; 89 old__atexit = __atexit; 90 _MUTEX_UNLOCK(&atexit_mutex); 91 if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) 92 return (-1); 93 _MUTEX_LOCK(&atexit_mutex); 94 if (old__atexit != __atexit) { 95 /* Lost race, retry operation */ 96 _MUTEX_UNLOCK(&atexit_mutex); 97 free(p); 98 _MUTEX_LOCK(&atexit_mutex); 99 p = __atexit; 100 continue; 101 } 102 p->ind = 0; 103 p->next = __atexit; 104 __atexit = p; 105 } 106 p->fns[p->ind++] = *fptr; 107 _MUTEX_UNLOCK(&atexit_mutex); 108 return 0; 109 } 110 111 /* 112 * Register a function to be performed at exit. 113 */ 114 int 115 atexit(void (*func)(void)) 116 { 117 struct atexit_fn fn; 118 int error; 119 120 fn.fn_type = ATEXIT_FN_STD; 121 fn.fn_ptr.std_func = func; 122 fn.fn_arg = NULL; 123 fn.fn_dso = NULL; 124 125 error = atexit_register(&fn); 126 return (error); 127 } 128 129 /* 130 * Register a function to be performed at exit or when an shared object 131 * with given dso handle is unloaded dynamically. 132 */ 133 int 134 __cxa_atexit(void (*func)(void *), void *arg, void *dso) 135 { 136 struct atexit_fn fn; 137 int error; 138 139 fn.fn_type = ATEXIT_FN_CXA; 140 fn.fn_ptr.cxa_func = func; 141 fn.fn_arg = arg; 142 fn.fn_dso = dso; 143 144 error = atexit_register(&fn); 145 return (error); 146 } 147 148 #pragma weak __pthread_cxa_finalize 149 void __pthread_cxa_finalize(const struct dl_phdr_info *); 150 151 /* 152 * Call all handlers registered with __cxa_atexit for the shared 153 * object owning 'dso'. Note: if 'dso' is NULL, then all remaining 154 * handlers are called. 155 */ 156 void 157 __cxa_finalize(void *dso) 158 { 159 struct dl_phdr_info phdr_info; 160 struct atexit *p; 161 struct atexit_fn fn; 162 int n, has_phdr; 163 164 if (dso != NULL) 165 has_phdr = _rtld_addr_phdr(dso, &phdr_info); 166 else 167 has_phdr = 0; 168 169 _MUTEX_LOCK(&atexit_mutex); 170 for (p = __atexit; p; p = p->next) { 171 for (n = p->ind; --n >= 0;) { 172 if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) 173 continue; /* already been called */ 174 fn = p->fns[n]; 175 if (dso != NULL && dso != fn.fn_dso) { 176 /* wrong DSO ? */ 177 if (!has_phdr || !__elf_phdr_match_addr( 178 &phdr_info, fn.fn_ptr.cxa_func)) 179 continue; 180 } 181 /* 182 Mark entry to indicate that this particular handler 183 has already been called. 184 */ 185 p->fns[n].fn_type = ATEXIT_FN_EMPTY; 186 _MUTEX_UNLOCK(&atexit_mutex); 187 188 /* Call the function of correct type. */ 189 if (fn.fn_type == ATEXIT_FN_CXA) 190 fn.fn_ptr.cxa_func(fn.fn_arg); 191 else if (fn.fn_type == ATEXIT_FN_STD) 192 fn.fn_ptr.std_func(); 193 _MUTEX_LOCK(&atexit_mutex); 194 } 195 } 196 _MUTEX_UNLOCK(&atexit_mutex); 197 if (dso == NULL) 198 _MUTEX_DESTROY(&atexit_mutex); 199 200 if (has_phdr && &__pthread_cxa_finalize != NULL) 201 __pthread_cxa_finalize(&phdr_info); 202 } 203