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 <sys/cdefs.h> 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 49 static void exit_thread(void) __dead2; 50 51 __weak_reference(_Tthr_exit, pthread_exit); 52 __weak_reference(_Tthr_exit, _pthread_exit); 53 54 #ifdef _PTHREAD_FORCED_UNWIND 55 static int message_printed; 56 57 static void thread_unwind(void) __dead2; 58 #ifdef PIC 59 static void thread_uw_init(void); 60 static _Unwind_Reason_Code thread_unwind_stop(int version, 61 _Unwind_Action actions, 62 uint64_t exc_class, 63 struct _Unwind_Exception *exc_obj, 64 struct _Unwind_Context *context, void *stop_parameter); 65 /* unwind library pointers */ 66 static _Unwind_Reason_Code (*uwl_forcedunwind)(struct _Unwind_Exception *, 67 _Unwind_Stop_Fn, void *); 68 static uintptr_t (*uwl_getcfa)(struct _Unwind_Context *); 69 70 static void 71 thread_uw_init(void) 72 { 73 static int inited = 0; 74 Dl_info dli; 75 void *handle; 76 void *forcedunwind, *getcfa; 77 78 if (inited) 79 return; 80 handle = RTLD_DEFAULT; 81 if ((forcedunwind = dlsym(handle, "_Unwind_ForcedUnwind")) != NULL) { 82 if (dladdr(forcedunwind, &dli)) { 83 /* 84 * Make sure the address is always valid by holding the library, 85 * also assume functions are in same library. 86 */ 87 if ((handle = dlopen(dli.dli_fname, RTLD_LAZY)) != NULL) { 88 forcedunwind = dlsym(handle, "_Unwind_ForcedUnwind"); 89 getcfa = dlsym(handle, "_Unwind_GetCFA"); 90 if (forcedunwind != NULL && getcfa != NULL) { 91 uwl_getcfa = getcfa; 92 atomic_store_rel_ptr((volatile void *)&uwl_forcedunwind, 93 (uintptr_t)forcedunwind); 94 } else { 95 dlclose(handle); 96 } 97 } 98 } 99 } 100 inited = 1; 101 } 102 103 _Unwind_Reason_Code 104 _Unwind_ForcedUnwind(struct _Unwind_Exception *ex, _Unwind_Stop_Fn stop_func, 105 void *stop_arg) 106 { 107 return (*uwl_forcedunwind)(ex, stop_func, stop_arg); 108 } 109 110 uintptr_t 111 _Unwind_GetCFA(struct _Unwind_Context *context) 112 { 113 return (*uwl_getcfa)(context); 114 } 115 #else 116 #pragma weak _Unwind_GetCFA 117 #pragma weak _Unwind_ForcedUnwind 118 #endif /* PIC */ 119 120 static void 121 thread_unwind_cleanup(_Unwind_Reason_Code code __unused, 122 struct _Unwind_Exception *e __unused) 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 } 131 132 static _Unwind_Reason_Code 133 thread_unwind_stop(int version __unused, _Unwind_Action actions, 134 uint64_t exc_class __unused, 135 struct _Unwind_Exception *exc_obj __unused, 136 struct _Unwind_Context *context, void *stop_parameter __unused) 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 } 165 166 static void 167 thread_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 178 179 void 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 } 196 197 void 198 _thread_exit(const char *fname, int lineno, const char *msg) 199 { 200 201 _thread_exitf(fname, lineno, "%s", msg); 202 } 203 204 void 205 _Tthr_exit(void *status) 206 { 207 _pthread_exit_mask(status, NULL); 208 } 209 210 void 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 if (uwl_forcedunwind != NULL) { 244 #else 245 if (_Unwind_ForcedUnwind != NULL) { 246 #endif 247 if (curthread->unwind_disabled) { 248 if (message_printed == 0) { 249 message_printed = 1; 250 _thread_printf(2, "Warning: old _pthread_cleanup_push was called, " 251 "stack unwinding is disabled.\n"); 252 } 253 goto cleanup; 254 } 255 thread_unwind(); 256 257 } else { 258 cleanup: 259 while (curthread->cleanup != NULL) { 260 __pthread_cleanup_pop_imp(1); 261 } 262 __cxa_thread_call_dtors(); 263 264 exit_thread(); 265 } 266 267 #else 268 while (curthread->cleanup != NULL) { 269 __pthread_cleanup_pop_imp(1); 270 } 271 __cxa_thread_call_dtors(); 272 273 exit_thread(); 274 #endif /* _PTHREAD_FORCED_UNWIND */ 275 } 276 277 static void 278 exit_thread(void) 279 { 280 struct pthread *curthread = _get_curthread(); 281 282 free(curthread->name); 283 curthread->name = NULL; 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