thr_exit.c revision 304524 
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 304524 2016-08-20 11:58:23Z kib $");
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		/* Tell libc that it should call non-trivial TLS dtors. */
158		__cxa_thread_call_dtors();
159
160		exit_thread(); /* Never return! */
161	}
162
163	return (_URC_NO_REASON);
164}
165
166static void
167thread_unwind(void)
168{
169	struct pthread  *curthread = _get_curthread();
170
171	curthread->ex.exception_class = 0;
172	curthread->ex.exception_cleanup = thread_unwind_cleanup;
173	_Unwind_ForcedUnwind(&curthread->ex, thread_unwind_stop, NULL);
174	PANIC("_Unwind_ForcedUnwind returned");
175}
176
177#endif
178
179void
180_thread_exitf(const char *fname, int lineno, const char *fmt, ...)
181{
182	va_list ap;
183
184	/* Write an error message to the standard error file descriptor: */
185	_thread_printf(STDERR_FILENO, "Fatal error '");
186
187	va_start(ap, fmt);
188	_thread_vprintf(STDERR_FILENO, fmt, ap);
189	va_end(ap);
190
191	_thread_printf(STDERR_FILENO, "' at line %d in file %s (errno = %d)\n",
192	    lineno, fname, errno);
193
194	abort();
195}
196
197void
198_thread_exit(const char *fname, int lineno, const char *msg)
199{
200
201	_thread_exitf(fname, lineno, "%s", msg);
202}
203
204void
205_pthread_exit(void *status)
206{
207	_pthread_exit_mask(status, NULL);
208}
209
210void
211_pthread_exit_mask(void *status, sigset_t *mask)
212{
213	struct pthread *curthread = _get_curthread();
214
215	/* Check if this thread is already in the process of exiting: */
216	if (curthread->cancelling)
217		PANIC("Thread %p has called "
218		    "pthread_exit() from a destructor. POSIX 1003.1 "
219		    "1996 s16.2.5.2 does not allow this!", curthread);
220
221	/* Flag this thread as exiting. */
222	curthread->cancelling = 1;
223	curthread->no_cancel = 1;
224	curthread->cancel_async = 0;
225	curthread->cancel_point = 0;
226	if (mask != NULL)
227		__sys_sigprocmask(SIG_SETMASK, mask, NULL);
228	if (curthread->unblock_sigcancel) {
229		sigset_t set;
230
231		curthread->unblock_sigcancel = 0;
232		SIGEMPTYSET(set);
233		SIGADDSET(set, SIGCANCEL);
234		__sys_sigprocmask(SIG_UNBLOCK, mask, NULL);
235	}
236
237	/* Save the return value: */
238	curthread->ret = status;
239#ifdef _PTHREAD_FORCED_UNWIND
240
241#ifdef PIC
242	thread_uw_init();
243#endif /* PIC */
244
245#ifdef PIC
246	if (uwl_forcedunwind != NULL) {
247#else
248	if (_Unwind_ForcedUnwind != NULL) {
249#endif
250		if (curthread->unwind_disabled) {
251			if (message_printed == 0) {
252				message_printed = 1;
253				_thread_printf(2, "Warning: old _pthread_cleanup_push was called, "
254				  	"stack unwinding is disabled.\n");
255			}
256			goto cleanup;
257		}
258		thread_unwind();
259
260	} else {
261cleanup:
262		while (curthread->cleanup != NULL) {
263			__pthread_cleanup_pop_imp(1);
264		}
265		__cxa_thread_call_dtors();
266
267		exit_thread();
268	}
269
270#else
271	while (curthread->cleanup != NULL) {
272		__pthread_cleanup_pop_imp(1);
273	}
274	__cxa_thread_call_dtors();
275
276	exit_thread();
277#endif /* _PTHREAD_FORCED_UNWIND */
278}
279
280static void
281exit_thread(void)
282{
283	struct pthread *curthread = _get_curthread();
284
285	/* Check if there is thread specific data: */
286	if (curthread->specific != NULL) {
287		/* Run the thread-specific data destructors: */
288		_thread_cleanupspecific();
289	}
290
291	if (!_thr_isthreaded())
292		exit(0);
293
294	if (atomic_fetchadd_int(&_thread_active_threads, -1) == 1) {
295		exit(0);
296		/* Never reach! */
297	}
298
299	/* Tell malloc that the thread is exiting. */
300	_malloc_thread_cleanup();
301
302	THR_LOCK(curthread);
303	curthread->state = PS_DEAD;
304	if (curthread->flags & THR_FLAGS_NEED_SUSPEND) {
305		curthread->cycle++;
306		_thr_umtx_wake(&curthread->cycle, INT_MAX, 0);
307	}
308	if (!curthread->force_exit && SHOULD_REPORT_EVENT(curthread, TD_DEATH))
309		_thr_report_death(curthread);
310	/*
311	 * Thread was created with initial refcount 1, we drop the
312	 * reference count to allow it to be garbage collected.
313	 */
314	curthread->refcount--;
315	_thr_try_gc(curthread, curthread); /* thread lock released */
316
317#if defined(_PTHREADS_INVARIANTS)
318	if (THR_IN_CRITICAL(curthread))
319		PANIC("thread %p exits with resources held!", curthread);
320#endif
321	/*
322	 * Kernel will do wakeup at the address, so joiner thread
323	 * will be resumed if it is sleeping at the address.
324	 */
325	thr_exit(&curthread->tid);
326	PANIC("thr_exit() returned");
327	/* Never reach! */
328}
329