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  * 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 #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 }