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  * 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: src/lib/libc/stdlib/atexit.c,v 1.7 2003/12/19 17:11:20 kan Exp $");
  42
  43 #include "namespace.h"
  44 #include <stddef.h>
  45 #include <stdlib.h>
  46 #include <unistd.h>
  47 #include <pthread.h>
  48 #if defined(__DYNAMIC__)
  49 #include <dlfcn.h>
  50 #endif /* defined(__DYNAMIC__) */
  51 #include "atexit.h"
  52 #include "un-namespace.h"
  53
  54 #include "libc_private.h"
  55
  56 #define ATEXIT_FN_EMPTY 0
  57 #define ATEXIT_FN_STD   1
  58 #define ATEXIT_FN_CXA   2
  59
  60 static pthread_mutex_t atexit_mutex = PTHREAD_MUTEX_INITIALIZER;
  61
  62 #define _MUTEX_LOCK(x)          if (__isthreaded) _pthread_mutex_lock(x)
  63 #define _MUTEX_UNLOCK(x)        if (__isthreaded) _pthread_mutex_unlock(x)
  64
  65 struct atexit {
  66         struct atexit *next;                    /* next in list */
  67         int ind;                                /* next index in this table */
  68         struct atexit_fn {
  69                 int fn_type;                    /* ATEXIT_? from above */
  70                 union {
  71                         void (*std_func)(void);
  72                         void (*cxa_func)(void *);
  73                 } fn_ptr;                       /* function pointer */
  74                 void *fn_arg;                   /* argument for CXA callback */
  75                 void *fn_dso;                   /* shared module handle */
  76         } fns[ATEXIT_SIZE];                     /* the table itself */
  77 };
  78
  79 static struct atexit *__atexit;         /* points to head of LIFO stack */
  80 static int new_registration;
  81
  82 /*
  83  * Register the function described by 'fptr' to be called at application
  84  * exit or owning shared object unload time. This is a helper function
  85  * for atexit and __cxa_atexit.
  86  */
  87 static int
  88 atexit_register(struct atexit_fn *fptr)
  89 {
  90         static struct atexit __atexit0; /* one guaranteed table */
  91         struct atexit *p;
  92
  93         _MUTEX_LOCK(&atexit_mutex);
  94         if ((p = __atexit) == NULL)
  95                 __atexit = p = &__atexit0;
  96         else while (p->ind >= ATEXIT_SIZE) {
  97                 struct atexit *old__atexit;
  98                 old__atexit = __atexit;
  99                 _MUTEX_UNLOCK(&atexit_mutex);
 100                 if ((p = (struct atexit *)malloc(sizeof(*p))) == NULL)
 101                         return (-1);
 102                 _MUTEX_LOCK(&atexit_mutex);
 103                 if (old__atexit != __atexit) {
 104                         /* Lost race, retry operation */
 105                         _MUTEX_UNLOCK(&atexit_mutex);
 106                         free(p);
 107                         _MUTEX_LOCK(&atexit_mutex);
 108                         p = __atexit;
 109                         continue;
 110                 }
 111                 p->ind = 0;
 112                 p->next = __atexit;
 113                 __atexit = p;
 114         }
 115         p->fns[p->ind++] = *fptr;
 116         new_registration = 1;
 117         _MUTEX_UNLOCK(&atexit_mutex);
 118         return 0;
 119 }
 120
 121 /*
 122  * Register a function to be performed at exit.
 123  */
 124 int
 125 atexit(void (*func)(void))
 126 {
 127         struct atexit_fn fn;
 128         struct dl_info info;
 129         int error;
 130
 131         fn.fn_type = ATEXIT_FN_STD;
 132         fn.fn_ptr.std_func = func;;
 133         fn.fn_arg = NULL;
 134 #if defined(__DYNAMIC__)
 135         if ( dladdr(func, &info) )
 136                 fn.fn_dso = info.dli_fbase;
 137         else
 138                 fn.fn_dso = NULL;
 139 #else /* ! defined(__DYNAMIC__) */
 140         fn.fn_dso = NULL;
 141 #endif /* defined(__DYNAMIC__) */
 142
 143         error = atexit_register(&fn);
 144         return (error);
 145 }
 146
 147 /*
 148  * Register a function to be performed at exit or when an shared object
 149  * with given dso handle is unloaded dynamically.
 150  */
 151 int
 152 __cxa_atexit(void (*func)(void *), void *arg, void *dso)
 153 {
 154         struct atexit_fn fn;
 155         int error;
 156
 157         fn.fn_type = ATEXIT_FN_CXA;
 158         fn.fn_ptr.cxa_func = func;;
 159         fn.fn_arg = arg;
 160         fn.fn_dso = dso;
 161
 162         error = atexit_register(&fn);
 163         return (error);
 164 }
 165
 166 /*
 167  * Call all handlers registered with __cxa_atexit for the shared
 168  * object owning 'dso'.  Note: if 'dso' is NULL, then all remaining
 169  * handlers are called.
 170  */
 171 void
 172 __cxa_finalize(const void *dso)
 173 {
 174         struct atexit *p;
 175         struct atexit_fn fn;
 176         int n;
 177
 178         _MUTEX_LOCK(&atexit_mutex);
 179 restart:
 180         for (p = __atexit; p; p = p->next) {
 181                 for (n = p->ind; --n >= 0;) {
 182                         if (p->fns[n].fn_type == ATEXIT_FN_EMPTY)
 183                                 continue; /* already been called */
 184                         if (dso != NULL && dso != p->fns[n].fn_dso)
 185                                 continue; /* wrong DSO */
 186                         fn = p->fns[n];
 187                         /*
 188                           Mark entry to indicate that this particular handler
 189                           has already been called.
 190                         */
 191                         p->fns[n].fn_type = ATEXIT_FN_EMPTY;
 192                         new_registration = 0;
 193                         _MUTEX_UNLOCK(&atexit_mutex);
 194
 195                         /* Call the function of correct type. */
 196                         if (fn.fn_type == ATEXIT_FN_CXA)
 197                                 fn.fn_ptr.cxa_func(fn.fn_arg);
 198                         else if (fn.fn_type == ATEXIT_FN_STD)
 199                                 fn.fn_ptr.std_func();
 200                         _MUTEX_LOCK(&atexit_mutex);
 201                         if (new_registration)
 202                             goto restart;
 203                 }
 204         }
 205         _MUTEX_UNLOCK(&atexit_mutex);
 206 }