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 * $FreeBSD$
30 */
31
32 #include "namespace.h"
33 #include <errno.h>
34 #ifdef _PTHREAD_FORCED_UNWIND
35 #include <dlfcn.h>
36 #endif
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <pthread.h>
40 #include <sys/types.h>
41 #include <sys/signalvar.h>
42 #include "un-namespace.h"
43
44 #include "libc_private.h"
45 #include "thr_private.h"
46
47 void _pthread_exit(void *status);
48
49 static void exit_thread(void) __dead2;
50
51 __weak_reference(_pthread_exit, pthread_exit);
52
53 #ifdef _PTHREAD_FORCED_UNWIND
54 static int message_printed;
55
56 static void thread_unwind(void) __dead2;
57 #ifdef PIC
58 static void thread_uw_init(void);
59 static _Unwind_Reason_Code thread_unwind_stop(int version,
60 _Unwind_Action actions,
61 int64_t exc_class,
62 struct _Unwind_Exception *exc_obj,
63 struct _Unwind_Context *context, void *stop_parameter);
64 /* unwind library pointers */
65 static _Unwind_Reason_Code (*uwl_forcedunwind)(struct _Unwind_Exception *,
66 _Unwind_Stop_Fn, void *);
67 static unsigned long (*uwl_getcfa)(struct _Unwind_Context *);
68
69 static void
thread_uw_init(void)70 thread_uw_init(void)
71 {
72 static int inited = 0;
73 Dl_info dlinfo;
74 void *handle;
75 void *forcedunwind, *getcfa;
76
77 if (inited)
78 return;
79 handle = RTLD_DEFAULT;
80 if ((forcedunwind = dlsym(handle, "_Unwind_ForcedUnwind")) != NULL) {
81 if (dladdr(forcedunwind, &dlinfo)) {
82 /*
83 * Make sure the address is always valid by holding the library,
84 * also assume functions are in same library.
85 */
86 if ((handle = dlopen(dlinfo.dli_fname, RTLD_LAZY)) != NULL) {
87 forcedunwind = dlsym(handle, "_Unwind_ForcedUnwind");
88 getcfa = dlsym(handle, "_Unwind_GetCFA");
89 if (forcedunwind != NULL && getcfa != NULL) {
90 uwl_getcfa = getcfa;
91 atomic_store_rel_ptr((volatile void *)&uwl_forcedunwind,
92 (uintptr_t)forcedunwind);
93 } else {
94 dlclose(handle);
95 }
96 }
97 }
98 }
99 inited = 1;
100 }
101
102 _Unwind_Reason_Code
_Unwind_ForcedUnwind(struct _Unwind_Exception * ex,_Unwind_Stop_Fn stop_func,void * stop_arg)103 _Unwind_ForcedUnwind(struct _Unwind_Exception *ex, _Unwind_Stop_Fn stop_func,
104 void *stop_arg)
105 {
106 return (*uwl_forcedunwind)(ex, stop_func, stop_arg);
107 }
108
109 unsigned long
_Unwind_GetCFA(struct _Unwind_Context * context)110 _Unwind_GetCFA(struct _Unwind_Context *context)
111 {
112 return (*uwl_getcfa)(context);
113 }
114 #else
115 #pragma weak _Unwind_GetCFA
116 #pragma weak _Unwind_ForcedUnwind
117 #endif /* PIC */
118
119 static void
thread_unwind_cleanup(_Unwind_Reason_Code code,struct _Unwind_Exception * e)120 thread_unwind_cleanup(_Unwind_Reason_Code code, struct _Unwind_Exception *e)
121 {
122 /*
123 * Specification said that _Unwind_Resume should not be used here,
124 * instead, user should rethrow the exception. For C++ user, they
125 * should put "throw" sentence in catch(...) block.
126 */
127 PANIC("exception should be rethrown");
128 }
129
130 static _Unwind_Reason_Code
thread_unwind_stop(int version,_Unwind_Action actions,int64_t exc_class,struct _Unwind_Exception * exc_obj,struct _Unwind_Context * context,void * stop_parameter)131 thread_unwind_stop(int version, _Unwind_Action actions,
132 int64_t exc_class,
133 struct _Unwind_Exception *exc_obj,
134 struct _Unwind_Context *context, void *stop_parameter)
135 {
136 struct pthread *curthread = _get_curthread();
137 struct pthread_cleanup *cur;
138 uintptr_t cfa;
139 int done = 0;
140
141 /* XXX assume stack grows down to lower address */
142
143 cfa = _Unwind_GetCFA(context);
144 if (actions & _UA_END_OF_STACK ||
145 cfa >= (uintptr_t)curthread->unwind_stackend) {
146 done = 1;
147 }
148
149 while ((cur = curthread->cleanup) != NULL &&
150 (done || (uintptr_t)cur <= cfa)) {
151 __pthread_cleanup_pop_imp(1);
152 }
153
154 if (done)
155 exit_thread(); /* Never return! */
156
157 return (_URC_NO_REASON);
158 }
159
160 static void
thread_unwind(void)161 thread_unwind(void)
162 {
163 struct pthread *curthread = _get_curthread();
164
165 curthread->ex.exception_class = 0;
166 curthread->ex.exception_cleanup = thread_unwind_cleanup;
167 _Unwind_ForcedUnwind(&curthread->ex, thread_unwind_stop, NULL);
168 PANIC("_Unwind_ForcedUnwind returned");
169 }
170
171 #endif
172
173 void
_thread_exit(const char * fname,int lineno,const char * msg)174 _thread_exit(const char *fname, int lineno, const char *msg)
175 {
176
177 /* Write an error message to the standard error file descriptor: */
178 _thread_printf(2,
179 "Fatal error '%s' at line %d in file %s (errno = %d)\n",
180 msg, lineno, fname, errno);
181
182 abort();
183 }
184
185 void
_pthread_exit(void * status)186 _pthread_exit(void *status)
187 {
188 _pthread_exit_mask(status, NULL);
189 }
190
191 void
_pthread_exit_mask(void * status,sigset_t * mask)192 _pthread_exit_mask(void *status, sigset_t *mask)
193 {
194 struct pthread *curthread = _get_curthread();
195
196 /* Check if this thread is already in the process of exiting: */
197 if (curthread->cancelling) {
198 char msg[128];
199 snprintf(msg, sizeof(msg), "Thread %p has called "
200 "pthread_exit() from a destructor. POSIX 1003.1 "
201 "1996 s16.2.5.2 does not allow this!", curthread);
202 PANIC(msg);
203 }
204
205 /* Flag this thread as exiting. */
206 curthread->cancelling = 1;
207 curthread->no_cancel = 1;
208 curthread->cancel_async = 0;
209 curthread->cancel_point = 0;
210 if (mask != NULL)
211 __sys_sigprocmask(SIG_SETMASK, mask, NULL);
212 if (curthread->unblock_sigcancel) {
213 sigset_t set;
214
215 curthread->unblock_sigcancel = 0;
216 SIGEMPTYSET(set);
217 SIGADDSET(set, SIGCANCEL);
218 __sys_sigprocmask(SIG_UNBLOCK, mask, NULL);
219 }
220
221 /* Save the return value: */
222 curthread->ret = status;
223 #ifdef _PTHREAD_FORCED_UNWIND
224
225 #ifdef PIC
226 thread_uw_init();
227 #endif /* PIC */
228
229 #ifdef PIC
230 if (uwl_forcedunwind != NULL) {
231 #else
232 if (_Unwind_ForcedUnwind != NULL) {
233 #endif
234 if (curthread->unwind_disabled) {
235 if (message_printed == 0) {
236 message_printed = 1;
237 _thread_printf(2, "Warning: old _pthread_cleanup_push was called, "
238 "stack unwinding is disabled.\n");
239 }
240 goto cleanup;
241 }
242 thread_unwind();
243
244 } else {
245 cleanup:
246 while (curthread->cleanup != NULL) {
247 __pthread_cleanup_pop_imp(1);
248 }
249 exit_thread();
250 }
251
252 #else
253 while (curthread->cleanup != NULL) {
254 __pthread_cleanup_pop_imp(1);
255 }
256
257 exit_thread();
258 #endif /* _PTHREAD_FORCED_UNWIND */
259 }
260
261 static void
262 exit_thread(void)
263 {
264 struct pthread *curthread = _get_curthread();
265
266 /* Check if there is thread specific data: */
267 if (curthread->specific != NULL) {
268 /* Run the thread-specific data destructors: */
269 _thread_cleanupspecific();
270 }
271
272 if (!_thr_isthreaded())
273 exit(0);
274
275 if (atomic_fetchadd_int(&_thread_active_threads, -1) == 1) {
276 exit(0);
277 /* Never reach! */
278 }
279
280 /* Tell malloc that the thread is exiting. */
281 _malloc_thread_cleanup();
282
283 THR_LOCK(curthread);
284 curthread->state = PS_DEAD;
285 if (curthread->flags & THR_FLAGS_NEED_SUSPEND) {
286 curthread->cycle++;
287 _thr_umtx_wake(&curthread->cycle, INT_MAX, 0);
288 }
289 if (!curthread->force_exit && SHOULD_REPORT_EVENT(curthread, TD_DEATH))
290 _thr_report_death(curthread);
291 /*
292 * Thread was created with initial refcount 1, we drop the
293 * reference count to allow it to be garbage collected.
294 */
295 curthread->refcount--;
296 _thr_try_gc(curthread, curthread); /* thread lock released */
297
298 #if defined(_PTHREADS_INVARIANTS)
299 if (THR_IN_CRITICAL(curthread))
300 PANIC("thread exits with resources held!");
301 #endif
302 /*
303 * Kernel will do wakeup at the address, so joiner thread
304 * will be resumed if it is sleeping at the address.
305 */
306 thr_exit(&curthread->tid);
307 PANIC("thr_exit() returned");
308 /* Never reach! */
309 }
310