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 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)atexit.c 8.2 (Berkeley) 7/3/94"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "namespace.h" 40 #include <link.h> 41 #include <stddef.h> 42 #include <stdlib.h> 43 #include <unistd.h> 44 #include <pthread.h> 45 #include "atexit.h" 46 #include "un-namespace.h" 47 48 #include "libc_private.h" 49 50 #define ATEXIT_FN_EMPTY 0 51 #define ATEXIT_FN_STD 1 52 #define ATEXIT_FN_CXA 2 53 54 static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER; 55 56 #define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x) 57 #define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x) 58 #define _MUTEX_DESTROY(x) if (__isthreaded) _pthread_mutex_destroy(x) 59 60 struct atexit { 61 struct atexit *next; /* next in list */ 62 int ind; /* next index in this table */ 63 struct atexit_fn { 64 int fn_type; /* ATEXIT_? from above */ 65 union { 66 void (*std_func)(void); 67 void (*cxa_func)(void *); 68 } fn_ptr; /* function pointer */ 69 void *fn_arg; /* argument for CXA callback */ 70 void *fn_dso; /* shared module handle */ 71 } fns[ATEXIT_SIZE]; /* the table itself */ 72 }; 73 74 static struct atexit *__atexit; /* points to head of LIFO stack */ 75 76 /* 77 * Register the function described by 'fptr' to be called at application 78 * exit or owning shared object unload time. This is a helper function 79 * for atexit and __cxa_atexit. 80 */ 81 static int 82 atexit_register(struct atexit_fn *fptr) 83 { 84 static struct atexit __atexit0; /* one guaranteed table */ 85 struct atexit *p; 86 87 _MUTEX_LOCK(&atexit_mutex); 88 if ((p = __atexit) == NULL) 89 __atexit = p = &__atexit0; 90 else while (p->ind >= ATEXIT_SIZE) { 91 struct atexit *old__atexit; 92 old__atexit = __atexit; 93 _MUTEX_UNLOCK(&atexit_mutex); 94 if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) 95 return (-1); 96 _MUTEX_LOCK(&atexit_mutex); 97 if (old__atexit != __atexit) { 98 /* Lost race, retry operation */ 99 _MUTEX_UNLOCK(&atexit_mutex); 100 free(p); 101 _MUTEX_LOCK(&atexit_mutex); 102 p = __atexit; 103 continue; 104 } 105 p->ind = 0; 106 p->next = __atexit; 107 __atexit = p; 108 } 109 p->fns[p->ind++] = *fptr; 110 _MUTEX_UNLOCK(&atexit_mutex); 111 return 0; 112 } 113 114 /* 115 * Register a function to be performed at exit. 116 */ 117 int 118 atexit(void (*func)(void)) 119 { 120 struct atexit_fn fn; 121 int error; 122 123 fn.fn_type = ATEXIT_FN_STD; 124 fn.fn_ptr.std_func = func; 125 fn.fn_arg = NULL; 126 fn.fn_dso = NULL; 127 128 error = atexit_register(&fn); 129 return (error); 130 } 131 132 /* 133 * Register a function to be performed at exit or when an shared object 134 * with given dso handle is unloaded dynamically. 135 */ 136 int 137 __cxa_atexit(void (*func)(void *), void *arg, void *dso) 138 { 139 struct atexit_fn fn; 140 int error; 141 142 fn.fn_type = ATEXIT_FN_CXA; 143 fn.fn_ptr.cxa_func = func; 144 fn.fn_arg = arg; 145 fn.fn_dso = dso; 146 147 error = atexit_register(&fn); 148 return (error); 149 } 150 151 #pragma weak __pthread_cxa_finalize 152 void __pthread_cxa_finalize(const struct dl_phdr_info *); 153 154 /* 155 * Call all handlers registered with __cxa_atexit for the shared 156 * object owning 'dso'. Note: if 'dso' is NULL, then all remaining 157 * handlers are called. 158 */ 159 void 160 __cxa_finalize(void *dso) 161 { 162 struct dl_phdr_info phdr_info; 163 struct atexit *p; 164 struct atexit_fn fn; 165 int n, has_phdr; 166 167 if (dso != NULL) 168 has_phdr = _rtld_addr_phdr(dso, &phdr_info); 169 else 170 has_phdr = 0; 171 172 _MUTEX_LOCK(&atexit_mutex); 173 for (p = __atexit; p; p = p->next) { 174 for (n = p->ind; --n >= 0;) { 175 if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) 176 continue; /* already been called */ 177 fn = p->fns[n]; 178 if (dso != NULL && dso != fn.fn_dso) { 179 /* wrong DSO ? */ 180 if (!has_phdr || !__elf_phdr_match_addr( 181 &phdr_info, fn.fn_ptr.cxa_func)) 182 continue; 183 } 184 /* 185 Mark entry to indicate that this particular handler 186 has already been called. 187 */ 188 p->fns[n].fn_type = ATEXIT_FN_EMPTY; 189 _MUTEX_UNLOCK(&atexit_mutex); 190 191 /* Call the function of correct type. */ 192 if (fn.fn_type == ATEXIT_FN_CXA) 193 fn.fn_ptr.cxa_func(fn.fn_arg); 194 else if (fn.fn_type == ATEXIT_FN_STD) 195 fn.fn_ptr.std_func(); 196 _MUTEX_LOCK(&atexit_mutex); 197 } 198 } 199 _MUTEX_UNLOCK(&atexit_mutex); 200 if (dso == NULL) 201 _MUTEX_DESTROY(&atexit_mutex); 202 203 if (has_phdr && &__pthread_cxa_finalize != NULL) 204 __pthread_cxa_finalize(&phdr_info); 205 } 206