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  * $FreeBSD$
  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
  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
 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
 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, 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
 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
 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
 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
 186 _pthread_exit(void *status)
 187 {
 188         _pthread_exit_mask(status, NULL);
 189 }
 190
 191 void
 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 }