stdlib/FreeBSD/atexit.c

   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: src/lib/libc/stdlib/atexit.c,v 1.8 2007/01/09 00:28:09 imp Exp $");
  38
  39 #include "namespace.h"
  40 #include <stddef.h>
  41 #include <stdlib.h>
  42 #include <unistd.h>
  43 #include <pthread.h>
  44 #if defined(__DYNAMIC__) || defined (__BLOCKS__)
  45 #include <dlfcn.h>
  46 #endif /* defined(__DYNAMIC__) */
  47 #include "atexit.h"
  48 #include "un-namespace.h"
  49
  50 #ifdef __BLOCKS__
  51 #include <Block.h>
  52 #endif /* __BLOCKS__ */
  53 #include "libc_private.h"
  54
  55 #include <TargetConditionals.h>
  56
  57 #define ATEXIT_FN_EMPTY 0
  58 #define ATEXIT_FN_STD   1
  59 #define ATEXIT_FN_CXA   2
  60 #ifdef __BLOCKS__
  61 #define ATEXIT_FN_BLK   3
  62 #endif /* __BLOCKS__ */
  63
  64 static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER;
  65
  66 #define _MUTEX_LOCK(x)          if (__isthreaded) _pthread_mutex_lock(x)
  67 #define _MUTEX_UNLOCK(x)        if (__isthreaded) _pthread_mutex_unlock(x)
  68
  69 struct atexit {
  70         struct atexit *next;                    /* next in list */
  71         int ind;                                /* next index in this table */
  72         struct atexit_fn {
  73                 int fn_type;                    /* ATEXIT_? from above */
  74                 union {
  75                         void (*std_func)(void);
  76                         void (*cxa_func)(void *);
  77 #ifdef __BLOCKS__
  78                         void (^block)(void);
  79 #endif /* __BLOCKS__ */
  80                 } fn_ptr;                       /* function pointer */
  81                 void *fn_arg;                   /* argument for CXA callback */
  82                 void *fn_dso;                   /* shared module handle */
  83         } fns[ATEXIT_SIZE];                     /* the table itself */
  84 };
  85
  86 static struct atexit *__atexit;         /* points to head of LIFO stack */
  87 static int new_registration;
  88
  89 /*
  90  * Register the function described by 'fptr' to be called at application
  91  * exit or owning shared object unload time. This is a helper function
  92  * for atexit and __cxa_atexit.
  93  */
  94 static int
  95 atexit_register(struct atexit_fn *fptr)
  96 {
  97         static struct atexit __atexit0; /* one guaranteed table */
  98         struct atexit *p;
  99
 100         _MUTEX_LOCK(&atexit_mutex);
 101         if ((p = __atexit) == NULL)
 102                 __atexit = p = &__atexit0;
 103         else while (p->ind >= ATEXIT_SIZE) {
 104                 struct atexit *old__atexit;
 105                 old__atexit = __atexit;
 106                 _MUTEX_UNLOCK(&atexit_mutex);
 107                 if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL)
 108                         return (-1);
 109                 _MUTEX_LOCK(&atexit_mutex);
 110                 if (old__atexit != __atexit) {
 111                         /* Lost race, retry operation */
 112                         _MUTEX_UNLOCK(&atexit_mutex);
 113                         free(p);
 114                         _MUTEX_LOCK(&atexit_mutex);
 115                         p = __atexit;
 116                         continue;
 117                 }
 118                 p->ind = 0;
 119                 p->next = __atexit;
 120                 __atexit = p;
 121         }
 122         p->fns[p->ind++] = *fptr;
 123         new_registration = 1;
 124         _MUTEX_UNLOCK(&atexit_mutex);
 125         return 0;
 126 }
 127
 128 /*
 129  * Register a function to be performed at exit.
 130  */
 131 int
 132 atexit(void (*func)(void))
 133 {
 134         struct atexit_fn fn;
 135         struct dl_info info;
 136         int error;
 137
 138         fn.fn_type = ATEXIT_FN_STD;
 139         fn.fn_ptr.std_func = func;
 140         fn.fn_arg = NULL;
 141 #if defined(__DYNAMIC__)
 142         if ( dladdr(func, &info) )
 143                 fn.fn_dso = info.dli_fbase;
 144         else
 145                 fn.fn_dso = NULL;
 146 #else /* ! defined(__DYNAMIC__) */
 147         fn.fn_dso = NULL;
 148 #endif /* defined(__DYNAMIC__) */
 149
 150         error = atexit_register(&fn);
 151         return (error);
 152 }
 153
 154 #ifdef __BLOCKS__
 155 int
 156 atexit_b(void (^block)(void))
 157 {
 158         struct atexit_fn fn;
 159         struct dl_info info;
 160         int error;
 161
 162         fn.fn_type = ATEXIT_FN_BLK;
 163         fn.fn_ptr.block = Block_copy(block);
 164         fn.fn_arg = NULL;
 165 #if defined(__DYNAMIC__)
 166         if ( dladdr(block, &info) )
 167                 fn.fn_dso = info.dli_fbase;
 168         else
 169                 fn.fn_dso = NULL;
 170 #else /* ! defined(__DYNAMIC__) */
 171         fn.fn_dso = NULL;
 172 #endif /* defined(__DYNAMIC__) */
 173
 174         error = atexit_register(&fn);
 175         return (error);
 176 }
 177 #endif /* __BLOCKS__ */
 178
 179 /*
 180  * Register a function to be performed at exit or when an shared object
 181  * with given dso handle is unloaded dynamically.
 182  */
 183 int
 184 __cxa_atexit(void (*func)(void *), void *arg, void *dso)
 185 {
 186         struct atexit_fn fn;
 187         int error;
 188
 189         fn.fn_type = ATEXIT_FN_CXA;
 190         fn.fn_ptr.cxa_func = func;;
 191         fn.fn_arg = arg;
 192         fn.fn_dso = dso;
 193
 194         error = atexit_register(&fn);
 195         return (error);
 196 }
 197
 198 /*
 199  * Call all handlers registered with __cxa_atexit for the shared
 200  * object owning 'dso'.  Note: if 'dso' is NULL, then all remaining
 201  * handlers are called.
 202  */
 203 void
 204 __cxa_finalize(const void *dso)
 205 {
 206         struct atexit *p;
 207         struct atexit_fn fn;
 208         int n;
 209
 210         _MUTEX_LOCK(&atexit_mutex);
 211 restart:
 212         for (p = __atexit; p; p = p->next) {
 213                 for (n = p->ind; --n >= 0;) {
 214                         if (p->fns[n].fn_type == ATEXIT_FN_EMPTY)
 215                                 continue; /* already been called */
 216                         if (dso != NULL && dso != p->fns[n].fn_dso)
 217                                 continue; /* wrong DSO */
 218                         fn = p->fns[n];
 219                         /*
 220                           Mark entry to indicate that this particular handler
 221                           has already been called.
 222                         */
 223                         p->fns[n].fn_type = ATEXIT_FN_EMPTY;
 224                         new_registration = 0;
 225                         _MUTEX_UNLOCK(&atexit_mutex);
 226
 227                         /* Call the function of correct type. */
 228                         if (fn.fn_type == ATEXIT_FN_CXA)
 229                                 fn.fn_ptr.cxa_func(fn.fn_arg);
 230                         else if (fn.fn_type == ATEXIT_FN_STD)
 231                                 fn.fn_ptr.std_func();
 232 #ifdef __BLOCKS__
 233                         else if (fn.fn_type == ATEXIT_FN_BLK)
 234                                 fn.fn_ptr.block();
 235 #endif /* __BLOCKS__ */
 236                         _MUTEX_LOCK(&atexit_mutex);
 237                         if (new_registration)
 238                             goto restart;
 239                 }
 240         }
 241         _MUTEX_UNLOCK(&atexit_mutex);
 242 }
 243
 244 #if !TARGET_IPHONE_SIMULATOR && (__i386__ || __x86_64__)
 245 /*
 246  * Support for thread_local in C++, using existing _tlv_atexit() in libdyld
 247  */
 248
 249 void _tlv_atexit(void(*f)(void*), void* arg); /* in libdyld */
 250
 251 void
 252 __cxa_thread_atexit(void(*f)(void*), void* arg)
 253 {
 254     _tlv_atexit(f, arg);
 255 }
 256 #endif