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 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 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 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 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 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 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 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 197 _thread_exit(const char *fname, int lineno, const char *msg) 198 { 199 200 _thread_exitf(fname, lineno, "%s", msg); 201 } 202 203 void 204 _Tthr_exit(void *status) 205 { 206 _pthread_exit_mask(status, NULL); 207 } 208 209 void 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