lib/libthr/thread/thr_exit.c

   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("$FreeBSD$");
  32
  33 #include "namespace.h"
  34 #include <errno.h>
  35 #ifdef _PTHREAD_FORCED_UNWIND
  36 #include <dlfcn.h>
  37 #endif
  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 void    _pthread_exit(void *status);
  49
  50 static void     exit_thread(void) __dead2;
  51
  52 __weak_reference(_pthread_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         int64_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 unsigned long (*uwl_getcfa)(struct _Unwind_Context *);
  69
  70 static void
  71 thread_uw_init(void)
  72 {
  73         static int inited = 0;
  74         Dl_info dlinfo;
  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, &dlinfo)) {
  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(dlinfo.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 unsigned long
 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, struct _Unwind_Exception *e)
 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, _Unwind_Action actions,
 133         int64_t exc_class,
 134         struct _Unwind_Exception *exc_obj,
 135         struct _Unwind_Context *context, void *stop_parameter)
 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                 exit_thread(); /* Never return! */
 157
 158         return (_URC_NO_REASON);
 159 }
 160
 161 static void
 162 thread_unwind(void)
 163 {
 164         struct pthread  *curthread = _get_curthread();
 165
 166         curthread->ex.exception_class = 0;
 167         curthread->ex.exception_cleanup = thread_unwind_cleanup;
 168         _Unwind_ForcedUnwind(&curthread->ex, thread_unwind_stop, NULL);
 169         PANIC("_Unwind_ForcedUnwind returned");
 170 }
 171
 172 #endif
 173
 174 void
 175 _thread_exit(const char *fname, int lineno, const char *msg)
 176 {
 177
 178         /* Write an error message to the standard error file descriptor: */
 179         _thread_printf(2,
 180             "Fatal error '%s' at line %d in file %s (errno = %d)\n",
 181             msg, lineno, fname, errno);
 182
 183         abort();
 184 }
 185
 186 void
 187 _pthread_exit(void *status)
 188 {
 189         _pthread_exit_mask(status, NULL);
 190 }
 191
 192 void
 193 _pthread_exit_mask(void *status, sigset_t *mask)
 194 {
 195         struct pthread *curthread = _get_curthread();
 196
 197         /* Check if this thread is already in the process of exiting: */
 198         if (curthread->cancelling) {
 199                 char msg[128];
 200                 snprintf(msg, sizeof(msg), "Thread %p has called "
 201                     "pthread_exit() from a destructor. POSIX 1003.1 "
 202                     "1996 s16.2.5.2 does not allow this!", curthread);
 203                 PANIC(msg);
 204         }
 205
 206         /* Flag this thread as exiting. */
 207         curthread->cancelling = 1;
 208         curthread->no_cancel = 1;
 209         curthread->cancel_async = 0;
 210         curthread->cancel_point = 0;
 211         if (mask != NULL)
 212                 __sys_sigprocmask(SIG_SETMASK, mask, NULL);
 213         if (curthread->unblock_sigcancel) {
 214                 sigset_t set;
 215
 216                 curthread->unblock_sigcancel = 0;
 217                 SIGEMPTYSET(set);
 218                 SIGADDSET(set, SIGCANCEL);
 219                 __sys_sigprocmask(SIG_UNBLOCK, mask, NULL);
 220         }
 221
 222         /* Save the return value: */
 223         curthread->ret = status;
 224 #ifdef _PTHREAD_FORCED_UNWIND
 225
 226 #ifdef PIC
 227         thread_uw_init();
 228 #endif /* PIC */
 229
 230 #ifdef PIC
 231         if (uwl_forcedunwind != NULL) {
 232 #else
 233         if (_Unwind_ForcedUnwind != NULL) {
 234 #endif
 235                 if (curthread->unwind_disabled) {
 236                         if (message_printed == 0) {
 237                                 message_printed = 1;
 238                                 _thread_printf(2, "Warning: old _pthread_cleanup_push was called, "
 239                                         "stack unwinding is disabled.\n");
 240                         }
 241                         goto cleanup;
 242                 }
 243                 thread_unwind();
 244
 245         } else {
 246 cleanup:
 247                 while (curthread->cleanup != NULL) {
 248                         __pthread_cleanup_pop_imp(1);
 249                 }
 250                 exit_thread();
 251         }
 252
 253 #else
 254         while (curthread->cleanup != NULL) {
 255                 __pthread_cleanup_pop_imp(1);
 256         }
 257
 258         exit_thread();
 259 #endif /* _PTHREAD_FORCED_UNWIND */
 260 }
 261
 262 static void
 263 exit_thread(void)
 264 {
 265         struct pthread *curthread = _get_curthread();
 266
 267         /* Check if there is thread specific data: */
 268         if (curthread->specific != NULL) {
 269                 /* Run the thread-specific data destructors: */
 270                 _thread_cleanupspecific();
 271         }
 272
 273         if (!_thr_isthreaded())
 274                 exit(0);
 275
 276         if (atomic_fetchadd_int(&_thread_active_threads, -1) == 1) {
 277                 exit(0);
 278                 /* Never reach! */
 279         }
 280
 281         /* Tell malloc that the thread is exiting. */
 282         _malloc_thread_cleanup();
 283
 284         THR_LOCK(curthread);
 285         curthread->state = PS_DEAD;
 286         if (curthread->flags & THR_FLAGS_NEED_SUSPEND) {
 287                 curthread->cycle++;
 288                 _thr_umtx_wake(&curthread->cycle, INT_MAX, 0);
 289         }
 290         if (!curthread->force_exit && SHOULD_REPORT_EVENT(curthread, TD_DEATH))
 291                 _thr_report_death(curthread);
 292         /*
 293          * Thread was created with initial refcount 1, we drop the
 294          * reference count to allow it to be garbage collected.
 295          */
 296         curthread->refcount--;
 297         _thr_try_gc(curthread, curthread); /* thread lock released */
 298
 299 #if defined(_PTHREADS_INVARIANTS)
 300         if (THR_IN_CRITICAL(curthread))
 301                 PANIC("thread exits with resources held!");
 302 #endif
 303         /*
 304          * Kernel will do wakeup at the address, so joiner thread
 305          * will be resumed if it is sleeping at the address.
 306          */
 307         thr_exit(&curthread->tid);
 308         PANIC("thr_exit() returned");
 309         /* Never reach! */
 310 }