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 int __cxa_atexit(void (*)(void *), void *, void *); 48 49 #define ATEXIT_FN_EMPTY 0 50 #define ATEXIT_FN_STD 1 51 #define ATEXIT_FN_CXA 2 52 53 static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER; 54 55 #define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x) 56 #define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x) 57 #define _MUTEX_DESTROY(x) if (__isthreaded) _pthread_mutex_destroy(x) 58 59 struct atexit { 60 struct atexit *next; /* next in list */ 61 int ind; /* next index in this table */ 62 struct atexit_fn { 63 int fn_type; /* ATEXIT_? from above */ 64 union { 65 void (*std_func)(void); 66 void (*cxa_func)(void *); 67 } fn_ptr; /* function pointer */ 68 void *fn_arg; /* argument for CXA callback */ 69 void *fn_dso; /* shared module handle */ 70 } fns[ATEXIT_SIZE]; /* the table itself */ 71 }; 72 73 static struct atexit *__atexit; /* points to head of LIFO stack */ 74 75 /* 76 * Register the function described by 'fptr' to be called at application 77 * exit or owning shared object unload time. This is a helper function 78 * for atexit and __cxa_atexit. 79 */ 80 static int 81 atexit_register(struct atexit_fn *fptr) 82 { 83 static struct atexit __atexit0; /* one guaranteed table */ 84 struct atexit *p; 85 86 _MUTEX_LOCK(&atexit_mutex); 87 if ((p = __atexit) == NULL) 88 __atexit = p = &__atexit0; 89 else while (p->ind >= ATEXIT_SIZE) { 90 struct atexit *old__atexit; 91 old__atexit = __atexit; 92 _MUTEX_UNLOCK(&atexit_mutex); 93 if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) 94 return (-1); 95 _MUTEX_LOCK(&atexit_mutex); 96 if (old__atexit != __atexit) { 97 /* Lost race, retry operation */ 98 _MUTEX_UNLOCK(&atexit_mutex); 99 free(p); 100 _MUTEX_LOCK(&atexit_mutex); 101 p = __atexit; 102 continue; 103 } 104 p->ind = 0; 105 p->next = __atexit; 106 __atexit = p; 107 } 108 p->fns[p->ind++] = *fptr; 109 _MUTEX_UNLOCK(&atexit_mutex); 110 return 0; 111 } 112 113 /* 114 * Register a function to be performed at exit. 115 */ 116 int 117 atexit(void (*func)(void)) 118 { 119 struct atexit_fn fn; 120 int error; 121 122 fn.fn_type = ATEXIT_FN_STD; 123 fn.fn_ptr.std_func = func; 124 fn.fn_arg = NULL; 125 fn.fn_dso = NULL; 126 127 error = atexit_register(&fn); 128 return (error); 129 } 130 131 /* 132 * Register a function to be performed at exit or when an shared object 133 * with given dso handle is unloaded dynamically. 134 */ 135 int 136 __cxa_atexit(void (*func)(void *), void *arg, void *dso) 137 { 138 struct atexit_fn fn; 139 int error; 140 141 fn.fn_type = ATEXIT_FN_CXA; 142 fn.fn_ptr.cxa_func = func; 143 fn.fn_arg = arg; 144 fn.fn_dso = dso; 145 146 error = atexit_register(&fn); 147 return (error); 148 } 149 150 #pragma weak __pthread_cxa_finalize 151 void __pthread_cxa_finalize(const struct dl_phdr_info *); 152 153 static int global_exit; 154 155 /* 156 * Call all handlers registered with __cxa_atexit for the shared 157 * object owning 'dso'. Note: if 'dso' is NULL, then all remaining 158 * handlers are called. 159 */ 160 void 161 __cxa_finalize(void *dso) 162 { 163 struct dl_phdr_info phdr_info; 164 struct atexit *p; 165 struct atexit_fn fn; 166 int n, has_phdr; 167 168 if (dso != NULL) { 169 has_phdr = _rtld_addr_phdr(dso, &phdr_info); 170 } else { 171 has_phdr = 0; 172 global_exit = 1; 173 } 174 175 _MUTEX_LOCK(&atexit_mutex); 176 for (p = __atexit; p; p = p->next) { 177 for (n = p->ind; --n >= 0;) { 178 if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) 179 continue; /* already been called */ 180 fn = p->fns[n]; 181 if (dso != NULL && dso != fn.fn_dso) { 182 /* wrong DSO ? */ 183 if (!has_phdr || global_exit || 184 !__elf_phdr_match_addr(&phdr_info, 185 fn.fn_ptr.cxa_func)) 186 continue; 187 } 188 /* 189 Mark entry to indicate that this particular handler 190 has already been called. 191 */ 192 p->fns[n].fn_type = ATEXIT_FN_EMPTY; 193 _MUTEX_UNLOCK(&atexit_mutex); 194 195 /* Call the function of correct type. */ 196 if (fn.fn_type == ATEXIT_FN_CXA) 197 fn.fn_ptr.cxa_func(fn.fn_arg); 198 else if (fn.fn_type == ATEXIT_FN_STD) 199 fn.fn_ptr.std_func(); 200 _MUTEX_LOCK(&atexit_mutex); 201 } 202 } 203 _MUTEX_UNLOCK(&atexit_mutex); 204 if (dso == NULL) 205 _MUTEX_DESTROY(&atexit_mutex); 206 207 if (has_phdr && !global_exit && &__pthread_cxa_finalize != NULL) 208 __pthread_cxa_finalize(&phdr_info); 209 } 210