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)
34static 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
64static 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
69struct 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
86static struct atexit *__atexit;		/* points to head of LIFO stack */
87static 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 */
94static int
95atexit_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 */
131int
132atexit(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__
155int
156atexit_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 */
183int
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 */
203void
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);
211restart:
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
249void _tlv_atexit(void(*f)(void*), void* arg); /* in libdyld */
250
251void
252__cxa_thread_atexit(void(*f)(void*), void* arg)
253{
254    _tlv_atexit(f, arg);
255}
256#endif
257