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cxa_thread_atexit.c revision 1.1.4.2 
      1 /* $NetBSD: cxa_thread_atexit.c,v 1.1.4.2 2017/08/29 09:43:16 bouyer Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2017 Joerg Sonnenberger <joerg (at) NetBSD.org>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __RCSID("$NetBSD: cxa_thread_atexit.c,v 1.1.4.2 2017/08/29 09:43:16 bouyer Exp $");
     31 
     32 #include <sys/queue.h>
     33 #include <dlfcn.h>
     34 #include <stdlib.h>
     35 
     36 #include "atexit.h"
     37 
     38 __dso_hidden bool __cxa_thread_atexit_used;
     39 
     40 struct cxa_dtor {
     41 	SLIST_ENTRY(cxa_dtor) link;
     42 	void *dso_symbol;
     43 	void *obj;
     44 	void (*dtor)(void *);
     45 };
     46 
     47 /* Assumes NULL initialization. */
     48 static __thread SLIST_HEAD(, cxa_dtor) cxa_dtors = SLIST_HEAD_INITIALIZER(cxa_dstors);
     49 
     50 void
     51 __cxa_thread_run_atexit(void)
     52 {
     53 	struct cxa_dtor *entry;
     54 
     55 	while ((entry = SLIST_FIRST(&cxa_dtors)) != NULL) {
     56 		SLIST_REMOVE_HEAD(&cxa_dtors, link);
     57 		(*entry->dtor)(entry->obj);
     58 		if (entry->dso_symbol)
     59 			__dl_cxa_refcount(entry->dso_symbol, -1);
     60 		free(entry);
     61 	}
     62 }
     63 
     64 /*
     65  * This dance is necessary since libstdc++ includes
     66  * __cxa_thread_atexit unconditionally.
     67  */
     68 __weak_alias(__cxa_thread_atexit, __cxa_thread_atexit_impl)
     69 int	__cxa_thread_atexit_impl(void (*)(void *), void *, void *);
     70 
     71 int
     72 __cxa_thread_atexit_impl(void (*dtor)(void *), void *obj, void *dso_symbol)
     73 {
     74 	struct cxa_dtor *entry;
     75 
     76 	__cxa_thread_atexit_used = true;
     77 
     78 	entry = malloc(sizeof(*entry));
     79 	if (entry == NULL)
     80 		return -1;
     81 	entry->dso_symbol = dso_symbol;
     82 	if (dso_symbol)
     83 		__dl_cxa_refcount(entry->dso_symbol, 1);
     84 	entry->obj = obj;
     85 	entry->dtor = dtor;
     86 	SLIST_INSERT_HEAD(&cxa_dtors, entry, link);
     87 	return 0;
     88 }
     89