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