thr_exit.c revision 302408 
1/*
2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the author nor the names of any co-contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: stable/11/lib/libthr/thread/thr_exit.c 301136 2016-06-01 16:12:26Z cem $");
32
33#include "namespace.h"
34#include <errno.h>
35#ifdef _PTHREAD_FORCED_UNWIND
36#include <dlfcn.h>
37#endif
38#include <stdarg.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <pthread.h>
42#include <sys/types.h>
43#include <sys/signalvar.h>
44#include "un-namespace.h"
45
46#include "libc_private.h"
47#include "thr_private.h"
48
49void	_pthread_exit(void *status);
50
51static void	exit_thread(void) __dead2;
52
53__weak_reference(_pthread_exit, pthread_exit);
54
55#ifdef _PTHREAD_FORCED_UNWIND
56static int message_printed;
57
58static void thread_unwind(void) __dead2;
59#ifdef PIC
60static void thread_uw_init(void);
61static _Unwind_Reason_Code thread_unwind_stop(int version,
62	_Unwind_Action actions,
63	int64_t exc_class,
64	struct _Unwind_Exception *exc_obj,
65	struct _Unwind_Context *context, void *stop_parameter);
66/* unwind library pointers */
67static _Unwind_Reason_Code (*uwl_forcedunwind)(struct _Unwind_Exception *,
68	_Unwind_Stop_Fn, void *);
69static unsigned long (*uwl_getcfa)(struct _Unwind_Context *);
70
71static void
72thread_uw_init(void)
73{
74	static int inited = 0;
75	Dl_info dlinfo;
76	void *handle;
77	void *forcedunwind, *getcfa;
78
79	if (inited)
80	    return;
81	handle = RTLD_DEFAULT;
82	if ((forcedunwind = dlsym(handle, "_Unwind_ForcedUnwind")) != NULL) {
83	    if (dladdr(forcedunwind, &dlinfo)) {
84		/*
85		 * Make sure the address is always valid by holding the library,
86		 * also assume functions are in same library.
87		 */
88		if ((handle = dlopen(dlinfo.dli_fname, RTLD_LAZY)) != NULL) {
89		    forcedunwind = dlsym(handle, "_Unwind_ForcedUnwind");
90		    getcfa = dlsym(handle, "_Unwind_GetCFA");
91		    if (forcedunwind != NULL && getcfa != NULL) {
92			uwl_getcfa = getcfa;
93			atomic_store_rel_ptr((volatile void *)&uwl_forcedunwind,
94				(uintptr_t)forcedunwind);
95		    } else {
96			dlclose(handle);
97		    }
98		}
99	    }
100	}
101	inited = 1;
102}
103
104_Unwind_Reason_Code
105_Unwind_ForcedUnwind(struct _Unwind_Exception *ex, _Unwind_Stop_Fn stop_func,
106	void *stop_arg)
107{
108	return (*uwl_forcedunwind)(ex, stop_func, stop_arg);
109}
110
111unsigned long
112_Unwind_GetCFA(struct _Unwind_Context *context)
113{
114	return (*uwl_getcfa)(context);
115}
116#else
117#pragma weak _Unwind_GetCFA
118#pragma weak _Unwind_ForcedUnwind
119#endif /* PIC */
120
121static void
122thread_unwind_cleanup(_Unwind_Reason_Code code, struct _Unwind_Exception *e)
123{
124	/*
125	 * Specification said that _Unwind_Resume should not be used here,
126	 * instead, user should rethrow the exception. For C++ user, they
127	 * should put "throw" sentence in catch(...) block.
128	 */
129	PANIC("exception should be rethrown");
130}
131
132static _Unwind_Reason_Code
133thread_unwind_stop(int version, _Unwind_Action actions,
134	int64_t exc_class,
135	struct _Unwind_Exception *exc_obj,
136	struct _Unwind_Context *context, void *stop_parameter)
137{
138	struct pthread *curthread = _get_curthread();
139	struct pthread_cleanup *cur;
140	uintptr_t cfa;
141	int done = 0;
142
143	/* XXX assume stack grows down to lower address */
144
145	cfa = _Unwind_GetCFA(context);
146	if (actions & _UA_END_OF_STACK ||
147	    cfa >= (uintptr_t)curthread->unwind_stackend) {
148		done = 1;
149	}
150
151	while ((cur = curthread->cleanup) != NULL &&
152	       (done || (uintptr_t)cur <= cfa)) {
153		__pthread_cleanup_pop_imp(1);
154	}
155
156	if (done)
157		exit_thread(); /* Never return! */
158
159	return (_URC_NO_REASON);
160}
161
162static void
163thread_unwind(void)
164{
165	struct pthread  *curthread = _get_curthread();
166
167	curthread->ex.exception_class = 0;
168	curthread->ex.exception_cleanup = thread_unwind_cleanup;
169	_Unwind_ForcedUnwind(&curthread->ex, thread_unwind_stop, NULL);
170	PANIC("_Unwind_ForcedUnwind returned");
171}
172
173#endif
174
175void
176_thread_exitf(const char *fname, int lineno, const char *fmt, ...)
177{
178	va_list ap;
179
180	/* Write an error message to the standard error file descriptor: */
181	_thread_printf(STDERR_FILENO, "Fatal error '");
182
183	va_start(ap, fmt);
184	_thread_vprintf(STDERR_FILENO, fmt, ap);
185	va_end(ap);
186
187	_thread_printf(STDERR_FILENO, "' at line %d in file %s (errno = %d)\n",
188	    lineno, fname, errno);
189
190	abort();
191}
192
193void
194_thread_exit(const char *fname, int lineno, const char *msg)
195{
196
197	_thread_exitf(fname, lineno, "%s", msg);
198}
199
200void
201_pthread_exit(void *status)
202{
203	_pthread_exit_mask(status, NULL);
204}
205
206void
207_pthread_exit_mask(void *status, sigset_t *mask)
208{
209	struct pthread *curthread = _get_curthread();
210
211	/* Check if this thread is already in the process of exiting: */
212	if (curthread->cancelling)
213		PANIC("Thread %p has called "
214		    "pthread_exit() from a destructor. POSIX 1003.1 "
215		    "1996 s16.2.5.2 does not allow this!", curthread);
216
217	/* Flag this thread as exiting. */
218	curthread->cancelling = 1;
219	curthread->no_cancel = 1;
220	curthread->cancel_async = 0;
221	curthread->cancel_point = 0;
222	if (mask != NULL)
223		__sys_sigprocmask(SIG_SETMASK, mask, NULL);
224	if (curthread->unblock_sigcancel) {
225		sigset_t set;
226
227		curthread->unblock_sigcancel = 0;
228		SIGEMPTYSET(set);
229		SIGADDSET(set, SIGCANCEL);
230		__sys_sigprocmask(SIG_UNBLOCK, mask, NULL);
231	}
232
233	/* Save the return value: */
234	curthread->ret = status;
235#ifdef _PTHREAD_FORCED_UNWIND
236
237#ifdef PIC
238	thread_uw_init();
239#endif /* PIC */
240
241#ifdef PIC
242	if (uwl_forcedunwind != NULL) {
243#else
244	if (_Unwind_ForcedUnwind != NULL) {
245#endif
246		if (curthread->unwind_disabled) {
247			if (message_printed == 0) {
248				message_printed = 1;
249				_thread_printf(2, "Warning: old _pthread_cleanup_push was called, "
250				  	"stack unwinding is disabled.\n");
251			}
252			goto cleanup;
253		}
254		thread_unwind();
255
256	} else {
257cleanup:
258		while (curthread->cleanup != NULL) {
259			__pthread_cleanup_pop_imp(1);
260		}
261		exit_thread();
262	}
263
264#else
265	while (curthread->cleanup != NULL) {
266		__pthread_cleanup_pop_imp(1);
267	}
268
269	exit_thread();
270#endif /* _PTHREAD_FORCED_UNWIND */
271}
272
273static void
274exit_thread(void)
275{
276	struct pthread *curthread = _get_curthread();
277
278	/* Check if there is thread specific data: */
279	if (curthread->specific != NULL) {
280		/* Run the thread-specific data destructors: */
281		_thread_cleanupspecific();
282	}
283
284	if (!_thr_isthreaded())
285		exit(0);
286
287	if (atomic_fetchadd_int(&_thread_active_threads, -1) == 1) {
288		exit(0);
289		/* Never reach! */
290	}
291
292	/* Tell malloc that the thread is exiting. */
293	_malloc_thread_cleanup();
294
295	THR_LOCK(curthread);
296	curthread->state = PS_DEAD;
297	if (curthread->flags & THR_FLAGS_NEED_SUSPEND) {
298		curthread->cycle++;
299		_thr_umtx_wake(&curthread->cycle, INT_MAX, 0);
300	}
301	if (!curthread->force_exit && SHOULD_REPORT_EVENT(curthread, TD_DEATH))
302		_thr_report_death(curthread);
303	/*
304	 * Thread was created with initial refcount 1, we drop the
305	 * reference count to allow it to be garbage collected.
306	 */
307	curthread->refcount--;
308	_thr_try_gc(curthread, curthread); /* thread lock released */
309
310#if defined(_PTHREADS_INVARIANTS)
311	if (THR_IN_CRITICAL(curthread))
312		PANIC("thread %p exits with resources held!", curthread);
313#endif
314	/*
315	 * Kernel will do wakeup at the address, so joiner thread
316	 * will be resumed if it is sleeping at the address.
317	 */
318	thr_exit(&curthread->tid);
319	PANIC("thr_exit() returned");
320	/* Never reach! */
321}
322