1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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 * 3. Neither the name of the author nor the names of any co-contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include "namespace.h"
33 #include <errno.h>
34 #ifdef _PTHREAD_FORCED_UNWIND
35 #include <dlfcn.h>
36 #endif
37 #include <stdarg.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <pthread.h>
41 #include <sys/types.h>
42 #include <sys/signalvar.h>
43 #include "un-namespace.h"
44
45 #include "libc_private.h"
46 #include "thr_private.h"
47
48 static void exit_thread(void) __dead2;
49
50 __weak_reference(_Tthr_exit, pthread_exit);
51 __weak_reference(_Tthr_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 uint64_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 uintptr_t (*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 dli;
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, &dli)) {
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(dli.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 uintptr_t
_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 __unused,struct _Unwind_Exception * e __unused)120 thread_unwind_cleanup(_Unwind_Reason_Code code __unused,
121 struct _Unwind_Exception *e __unused)
122 {
123 /*
124 * Specification said that _Unwind_Resume should not be used here,
125 * instead, user should rethrow the exception. For C++ user, they
126 * should put "throw" sentence in catch(...) block.
127 */
128 PANIC("exception should be rethrown");
129 }
130
131 static _Unwind_Reason_Code
thread_unwind_stop(int version __unused,_Unwind_Action actions,uint64_t exc_class __unused,struct _Unwind_Exception * exc_obj __unused,struct _Unwind_Context * context,void * stop_parameter __unused)132 thread_unwind_stop(int version __unused, _Unwind_Action actions,
133 uint64_t exc_class __unused,
134 struct _Unwind_Exception *exc_obj __unused,
135 struct _Unwind_Context *context, void *stop_parameter __unused)
136 {
137 struct pthread *curthread = _get_curthread();
138 struct pthread_cleanup *cur;
139 uintptr_t cfa;
140 int done = 0;
141
142 /* XXX assume stack grows down to lower address */
143
144 cfa = _Unwind_GetCFA(context);
145 if (actions & _UA_END_OF_STACK ||
146 cfa >= (uintptr_t)curthread->unwind_stackend) {
147 done = 1;
148 }
149
150 while ((cur = curthread->cleanup) != NULL &&
151 (done || (uintptr_t)cur <= cfa)) {
152 __pthread_cleanup_pop_imp(1);
153 }
154
155 if (done) {
156 /* Tell libc that it should call non-trivial TLS dtors. */
157 __cxa_thread_call_dtors();
158
159 exit_thread(); /* Never return! */
160 }
161
162 return (_URC_NO_REASON);
163 }
164
165 static void
thread_unwind(void)166 thread_unwind(void)
167 {
168 struct pthread *curthread = _get_curthread();
169
170 curthread->ex.exception_class = 0;
171 curthread->ex.exception_cleanup = thread_unwind_cleanup;
172 _Unwind_ForcedUnwind(&curthread->ex, thread_unwind_stop, NULL);
173 PANIC("_Unwind_ForcedUnwind returned");
174 }
175
176 #endif
177
178 void
_thread_exitf(const char * fname,int lineno,const char * fmt,...)179 _thread_exitf(const char *fname, int lineno, const char *fmt, ...)
180 {
181 va_list ap;
182
183 /* Write an error message to the standard error file descriptor: */
184 _thread_printf(STDERR_FILENO, "Fatal error '");
185
186 va_start(ap, fmt);
187 _thread_vprintf(STDERR_FILENO, fmt, ap);
188 va_end(ap);
189
190 _thread_printf(STDERR_FILENO, "' at line %d in file %s (errno = %d)\n",
191 lineno, fname, errno);
192
193 abort();
194 }
195
196 void
_thread_exit(const char * fname,int lineno,const char * msg)197 _thread_exit(const char *fname, int lineno, const char *msg)
198 {
199
200 _thread_exitf(fname, lineno, "%s", msg);
201 }
202
203 void
_Tthr_exit(void * status)204 _Tthr_exit(void *status)
205 {
206 _pthread_exit_mask(status, NULL);
207 }
208
209 void
_pthread_exit_mask(void * status,sigset_t * mask)210 _pthread_exit_mask(void *status, sigset_t *mask)
211 {
212 struct pthread *curthread = _get_curthread();
213
214 /* Check if this thread is already in the process of exiting: */
215 if (curthread->cancelling)
216 PANIC("Thread %p has called "
217 "pthread_exit() from a destructor. POSIX 1003.1 "
218 "1996 s16.2.5.2 does not allow this!", curthread);
219
220 /* Flag this thread as exiting. */
221 curthread->cancelling = 1;
222 curthread->no_cancel = 1;
223 curthread->cancel_async = 0;
224 curthread->cancel_point = 0;
225 if (mask != NULL)
226 __sys_sigprocmask(SIG_SETMASK, mask, NULL);
227 if (curthread->unblock_sigcancel) {
228 sigset_t set;
229
230 curthread->unblock_sigcancel = 0;
231 SIGEMPTYSET(set);
232 SIGADDSET(set, SIGCANCEL);
233 __sys_sigprocmask(SIG_UNBLOCK, mask, NULL);
234 }
235
236 /* Save the return value: */
237 curthread->ret = status;
238 #ifdef _PTHREAD_FORCED_UNWIND
239
240 #ifdef PIC
241 thread_uw_init();
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 {
257 cleanup:
258 while (curthread->cleanup != NULL) {
259 __pthread_cleanup_pop_imp(1);
260 }
261 __cxa_thread_call_dtors();
262
263 exit_thread();
264 }
265
266 #else
267 while (curthread->cleanup != NULL) {
268 __pthread_cleanup_pop_imp(1);
269 }
270 __cxa_thread_call_dtors();
271
272 exit_thread();
273 #endif /* _PTHREAD_FORCED_UNWIND */
274 }
275
276 static void
277 exit_thread(void)
278 {
279 struct pthread *curthread = _get_curthread();
280
281 free(curthread->name);
282 curthread->name = NULL;
283
284 /* Check if there is thread specific data: */
285 if (curthread->specific != NULL) {
286 /* Run the thread-specific data destructors: */
287 _thread_cleanupspecific();
288 }
289
290 if (!_thr_isthreaded())
291 exit(0);
292
293 if (atomic_fetchadd_int(&_thread_active_threads, -1) == 1) {
294 exit(0);
295 /* Never reach! */
296 }
297
298 /* Tell malloc that the thread is exiting. */
299 _malloc_thread_cleanup();
300
301 THR_LOCK(curthread);
302 curthread->state = PS_DEAD;
303 if (curthread->flags & THR_FLAGS_NEED_SUSPEND) {
304 curthread->cycle++;
305 _thr_umtx_wake(&curthread->cycle, INT_MAX, 0);
306 }
307 if (!curthread->force_exit && SHOULD_REPORT_EVENT(curthread, TD_DEATH))
308 _thr_report_death(curthread);
309 /*
310 * Thread was created with initial refcount 1, we drop the
311 * reference count to allow it to be garbage collected.
312 */
313 curthread->refcount--;
314 _thr_try_gc(curthread, curthread); /* thread lock released */
315
316 #if defined(_PTHREADS_INVARIANTS)
317 if (THR_IN_CRITICAL(curthread))
318 PANIC("thread %p exits with resources held!", curthread);
319 #endif
320 /*
321 * Kernel will do wakeup at the address, so joiner thread
322 * will be resumed if it is sleeping at the address.
323 */
324 thr_exit(&curthread->tid);
325 PANIC("thr_exit() returned");
326 /* Never reach! */
327 }
328