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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)atexit.c 8.2 (Berkeley) 7/3/94"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include "namespace.h" 44 #include <stddef.h> 45 #include <stdlib.h> 46 #include <unistd.h> 47 #include <pthread.h> 48 #include "atexit.h" 49 #include "un-namespace.h" 50 51 #include "libc_private.h" 52 53 #define ATEXIT_FN_EMPTY 0 54 #define ATEXIT_FN_STD 1 55 #define ATEXIT_FN_CXA 2 56 57 static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER; 58 59 #define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x) 60 #define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x) 61 62 struct atexit { 63 struct atexit *next; /* next in list */ 64 int ind; /* next index in this table */ 65 struct atexit_fn { 66 int fn_type; /* ATEXIT_? from above */ 67 union { 68 void (*std_func)(void); 69 void (*cxa_func)(void *); 70 } fn_ptr; /* function pointer */ 71 void *fn_arg; /* argument for CXA callback */ 72 void *fn_dso; /* shared module handle */ 73 } fns[ATEXIT_SIZE]; /* the table itself */ 74 }; 75 76 static struct atexit *__atexit; /* points to head of LIFO stack */ 77 78 /* 79 * Register the function described by 'fptr' to be called at application 80 * exit or owning shared object unload time. This is a helper function 81 * for atexit and __cxa_atexit. 82 */ 83 static int 84 atexit_register(struct atexit_fn *fptr) 85 { 86 static struct atexit __atexit0; /* one guaranteed table */ 87 struct atexit *p; 88 89 _MUTEX_LOCK(&atexit_mutex); 90 if ((p = __atexit) == NULL) 91 __atexit = p = &__atexit0; 92 else while (p->ind >= ATEXIT_SIZE) { 93 struct atexit *old__atexit; 94 old__atexit = __atexit; 95 _MUTEX_UNLOCK(&atexit_mutex); 96 if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL) 97 return (-1); 98 _MUTEX_LOCK(&atexit_mutex); 99 if (old__atexit != __atexit) { 100 /* Lost race, retry operation */ 101 _MUTEX_UNLOCK(&atexit_mutex); 102 free(p); 103 _MUTEX_LOCK(&atexit_mutex); 104 p = __atexit; 105 continue; 106 } 107 p->ind = 0; 108 p->next = __atexit; 109 __atexit = p; 110 } 111 p->fns[p->ind++] = *fptr; 112 _MUTEX_UNLOCK(&atexit_mutex); 113 return 0; 114 } 115 116 /* 117 * Register a function to be performed at exit. 118 */ 119 int 120 atexit(void (*func)(void)) 121 { 122 struct atexit_fn fn; 123 int error; 124 125 fn.fn_type = ATEXIT_FN_STD; 126 fn.fn_ptr.std_func = func;; 127 fn.fn_arg = NULL; 128 fn.fn_dso = NULL; 129 130 error = atexit_register(&fn); 131 return (error); 132 } 133 134 /* 135 * Register a function to be performed at exit or when an shared object 136 * with given dso handle is unloaded dynamically. 137 */ 138 int 139 __cxa_atexit(void (*func)(void *), void *arg, void *dso) 140 { 141 struct atexit_fn fn; 142 int error; 143 144 fn.fn_type = ATEXIT_FN_CXA; 145 fn.fn_ptr.cxa_func = func;; 146 fn.fn_arg = arg; 147 fn.fn_dso = dso; 148 149 error = atexit_register(&fn); 150 return (error); 151 } 152 153 /* 154 * Call all handlers registered with __cxa_atexit for the shared 155 * object owning 'dso'. Note: if 'dso' is NULL, then all remaining 156 * handlers are called. 157 */ 158 void 159 __cxa_finalize(void *dso) 160 { 161 struct atexit *p; 162 struct atexit_fn fn; 163 int n; 164 165 _MUTEX_LOCK(&atexit_mutex); 166 for (p = __atexit; p; p = p->next) { 167 for (n = p->ind; --n >= 0;) { 168 if (p->fns[n].fn_type == ATEXIT_FN_EMPTY) 169 continue; /* already been called */ 170 if (dso != NULL && dso != p->fns[n].fn_dso) 171 continue; /* wrong DSO */ 172 fn = p->fns[n]; 173 /* 174 Mark entry to indicate that this particular handler 175 has already been called. 176 */ 177 p->fns[n].fn_type = ATEXIT_FN_EMPTY; 178 _MUTEX_UNLOCK(&atexit_mutex); 179 180 /* Call the function of correct type. */ 181 if (fn.fn_type == ATEXIT_FN_CXA) 182 fn.fn_ptr.cxa_func(fn.fn_arg); 183 else if (fn.fn_type == ATEXIT_FN_STD) 184 fn.fn_ptr.std_func(); 185 _MUTEX_LOCK(&atexit_mutex); 186 } 187 } 188 _MUTEX_UNLOCK(&atexit_mutex); 189 } 190