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 <stddef.h> 41 #include <stdlib.h> 42 #include <unistd.h> 43 #include <pthread.h> 44 #include "atexit.h" 45 #include "un-namespace.h" 46 47 #include "libc_private.h" 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 58 struct atexit { 59 struct atexit *next; /* next in list */ 60 int ind; /* next index in this table */ 61 struct atexit_fn { 62 int fn_type; /* ATEXIT_? from above */ 63 union { 64 void (*std_func)(void); 65 void (*cxa_func)(void *); 66 } fn_ptr; /* function pointer */ 67 void *fn_arg; /* argument for CXA callback */ 68 void *fn_dso; /* shared module handle */ 69 } fns[ATEXIT_SIZE]; /* the table itself */ 70 }; 71 72 static struct atexit *__atexit; /* points to head of LIFO stack */ 73 74 /* 75 * Register the function described by 'fptr' to be called at application 76 * exit or owning shared object unload time. This is a helper function 77 * for atexit and __cxa_atexit. 78 */ 79 static int 80 atexit_register(struct atexit_fn *fptr) 81 { 82 static struct atexit __atexit0; /* one guaranteed table */ 83 struct atexit *p; 84 85 _MUTEX_LOCK(&atexit_mutex); 86 if ((p = __atexit) == NULL) 87 __atexit = p = &__atexit0; 88 else while (p->ind >= ATEXIT_SIZE) { 89 struct atexit *old__atexit; 90 old__atexit = __atexit; 91 _MUTEX_UNLOCK(&atexit_mutex); 92 if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) 93 return (-1); 94 _MUTEX_LOCK(&atexit_mutex); 95 if (old__atexit != __atexit) { 96 /* Lost race, retry operation */ 97 _MUTEX_UNLOCK(&atexit_mutex); 98 free(p); 99 _MUTEX_LOCK(&atexit_mutex); 100 p = __atexit; 101 continue; 102 } 103 p->ind = 0; 104 p->next = __atexit; 105 __atexit = p; 106 } 107 p->fns[p->ind++] = *fptr; 108 _MUTEX_UNLOCK(&atexit_mutex); 109 return 0; 110 } 111 112 /* 113 * Register a function to be performed at exit. 114 */ 115 int 116 atexit(void (*func)(void)) 117 { 118 struct atexit_fn fn; 119 int error; 120 121 fn.fn_type = ATEXIT_FN_STD; 122 fn.fn_ptr.std_func = func;; 123 fn.fn_arg = NULL; 124 fn.fn_dso = NULL; 125 126 error = atexit_register(&fn); 127 return (error); 128 } 129 130 /* 131 * Register a function to be performed at exit or when an shared object 132 * with given dso handle is unloaded dynamically. 133 */ 134 int 135 __cxa_atexit(void (*func)(void *), void *arg, void *dso) 136 { 137 struct atexit_fn fn; 138 int error; 139 140 fn.fn_type = ATEXIT_FN_CXA; 141 fn.fn_ptr.cxa_func = func;; 142 fn.fn_arg = arg; 143 fn.fn_dso = dso; 144 145 error = atexit_register(&fn); 146 return (error); 147 } 148 149 /* 150 * Call all handlers registered with __cxa_atexit for the shared 151 * object owning 'dso'. Note: if 'dso' is NULL, then all remaining 152 * handlers are called. 153 */ 154 void 155 __cxa_finalize(void *dso) 156 { 157 struct atexit *p; 158 struct atexit_fn fn; 159 int n; 160 161 _MUTEX_LOCK(&atexit_mutex); 162 for (p = __atexit; p; p = p->next) { 163 for (n = p->ind; --n >= 0;) { 164 if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) 165 continue; /* already been called */ 166 if (dso != NULL && dso != p->fns[n].fn_dso) 167 continue; /* wrong DSO */ 168 fn = p->fns[n]; 169 /* 170 Mark entry to indicate that this particular handler 171 has already been called. 172 */ 173 p->fns[n].fn_type = ATEXIT_FN_EMPTY; 174 _MUTEX_UNLOCK(&atexit_mutex); 175 176 /* Call the function of correct type. */ 177 if (fn.fn_type == ATEXIT_FN_CXA) 178 fn.fn_ptr.cxa_func(fn.fn_arg); 179 else if (fn.fn_type == ATEXIT_FN_STD) 180 fn.fn_ptr.std_func(); 181 _MUTEX_LOCK(&atexit_mutex); 182 } 183 } 184 _MUTEX_UNLOCK(&atexit_mutex); 185 } 186