libpthread/linuxthreads.old/join.c

   1 /* Linuxthreads - a simple clone()-based implementation of Posix        */
   2 /* threads for Linux.                                                   */
   3 /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
   4 /*                                                                      */
   5 /* This program is free software; you can redistribute it and/or        */
   6 /* modify it under the terms of the GNU Library General Public License  */
   7 /* as published by the Free Software Foundation; either version 2       */
   8 /* of the License, or (at your option) any later version.               */
   9 /*                                                                      */
  10 /* This program is distributed in the hope that it will be useful,      */
  11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
  12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
  13 /* GNU Library General Public License for more details.                 */
  14
  15 /* Thread termination and joining */
  16
  17 #include <features.h>
  18 #include <errno.h>
  19 #include <sched.h>
  20 #include <unistd.h>
  21 #include <stdlib.h>
  22 #include "pthread.h"
  23 #include "internals.h"
  24 #include "spinlock.h"
  25 #include "restart.h"
  26 #include "debug.h" /* PDEBUG, added by StS */
  27
  28 libpthread_hidden_proto(pthread_exit)
  29 void pthread_exit(void * retval)
  30 {
  31   __pthread_do_exit (retval, CURRENT_STACK_FRAME);
  32 }
  33 libpthread_hidden_def (pthread_exit)
  34
  35 void __pthread_do_exit(void *retval, char *currentframe)
  36 {
  37   pthread_descr self = thread_self();
  38   pthread_descr joining;
  39   struct pthread_request request;
  40   PDEBUG("self=%p, pid=%d\n", self, self->p_pid);
  41
  42   /* obey POSIX behavior and prevent cancellation functions from
  43    * being called more than once.
  44    * http://sourceware.org/ml/libc-ports/2006-10/msg00043.html
  45    */
  46   THREAD_SETMEM(self, p_cancelstate, PTHREAD_CANCEL_DISABLE);
  47   THREAD_SETMEM(self, p_canceltype, PTHREAD_CANCEL_DEFERRED);
  48
  49   /* Call cleanup functions and destroy the thread-specific data */
  50   __pthread_perform_cleanup(currentframe);
  51   __pthread_destroy_specifics();
  52   /* Store return value */
  53   __pthread_lock(THREAD_GETMEM(self, p_lock), self);
  54   THREAD_SETMEM(self, p_retval, retval);
  55   /* See whether we have to signal the death.  */
  56   if (THREAD_GETMEM(self, p_report_events))
  57     {
  58       /* See whether TD_DEATH is in any of the mask.  */
  59       int idx = __td_eventword (TD_DEATH);
  60       uint32_t mask = __td_eventmask (TD_DEATH);
  61
  62       if ((mask & (__pthread_threads_events.event_bits[idx]
  63                    | THREAD_GETMEM_NC(self,
  64                                    p_eventbuf.eventmask).event_bits[idx]))
  65           != 0)
  66         {
  67           /* Yep, we have to signal the death.  */
  68           THREAD_SETMEM(self, p_eventbuf.eventnum, TD_DEATH);
  69           THREAD_SETMEM(self, p_eventbuf.eventdata, self);
  70           __pthread_last_event = self;
  71
  72           /* Now call the function to signal the event.  */
  73           __linuxthreads_death_event();
  74         }
  75     }
  76   /* Say that we've terminated */
  77   THREAD_SETMEM(self, p_terminated, 1);
  78   /* See if someone is joining on us */
  79   joining = THREAD_GETMEM(self, p_joining);
  80   PDEBUG("joining = %p, pid=%d\n", joining, joining ? joining->p_pid : 0);
  81   __pthread_unlock(THREAD_GETMEM(self, p_lock));
  82   /* Restart joining thread if any */
  83   if (joining != NULL) restart(joining);
  84   /* If this is the initial thread, block until all threads have terminated.
  85      If another thread calls exit, we'll be terminated from our signal
  86      handler. */
  87   if (self == __pthread_main_thread && __pthread_manager_request >= 0) {
  88     request.req_thread = self;
  89     request.req_kind = REQ_MAIN_THREAD_EXIT;
  90     TEMP_FAILURE_RETRY(write(__pthread_manager_request,
  91                 (char *)&request, sizeof(request)));
  92     suspend(self);
  93     /* Main thread flushes stdio streams and runs atexit functions.
  94      * It also calls a handler within LinuxThreads which sends a process exit
  95      * request to the thread manager. */
  96     exit(0);
  97   }
  98   /* Exit the process (but don't flush stdio streams, and don't run
  99      atexit functions). */
 100   _exit(0);
 101 }
 102
 103 /* Function called by pthread_cancel to remove the thread from
 104    waiting on a condition variable queue. */
 105
 106 static int join_extricate_func(void *obj, pthread_descr th attribute_unused)
 107 {
 108   volatile pthread_descr self = thread_self();
 109   pthread_handle handle = obj;
 110   pthread_descr jo;
 111   int did_remove = 0;
 112
 113   __pthread_lock(&handle->h_lock, self);
 114   jo = handle->h_descr;
 115   did_remove = jo->p_joining != NULL;
 116   jo->p_joining = NULL;
 117   __pthread_unlock(&handle->h_lock);
 118
 119   return did_remove;
 120 }
 121
 122 int pthread_join(pthread_t thread_id, void ** thread_return)
 123 {
 124   volatile pthread_descr self = thread_self();
 125   struct pthread_request request;
 126   pthread_handle handle = thread_handle(thread_id);
 127   pthread_descr th;
 128   pthread_extricate_if extr;
 129   int already_canceled = 0;
 130   PDEBUG("\n");
 131
 132   /* Set up extrication interface */
 133   extr.pu_object = handle;
 134   extr.pu_extricate_func = join_extricate_func;
 135
 136   __pthread_lock(&handle->h_lock, self);
 137   if (invalid_handle(handle, thread_id)) {
 138     __pthread_unlock(&handle->h_lock);
 139     return ESRCH;
 140   }
 141   th = handle->h_descr;
 142   if (th == self) {
 143     __pthread_unlock(&handle->h_lock);
 144     return EDEADLK;
 145   }
 146   /* If detached or already joined, error */
 147   if (th->p_detached || th->p_joining != NULL) {
 148     __pthread_unlock(&handle->h_lock);
 149     return EINVAL;
 150   }
 151   /* If not terminated yet, suspend ourselves. */
 152   if (! th->p_terminated) {
 153     /* Register extrication interface */
 154     __pthread_set_own_extricate_if(self, &extr);
 155     if (!(THREAD_GETMEM(self, p_canceled)
 156         && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
 157       th->p_joining = self;
 158     else
 159       already_canceled = 1;
 160     __pthread_unlock(&handle->h_lock);
 161
 162     if (already_canceled) {
 163       __pthread_set_own_extricate_if(self, 0);
 164       __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
 165     }
 166
 167   PDEBUG("before suspend\n");
 168     suspend(self);
 169   PDEBUG("after suspend\n");
 170     /* Deregister extrication interface */
 171     __pthread_set_own_extricate_if(self, 0);
 172
 173     /* This is a cancellation point */
 174     if (THREAD_GETMEM(self, p_woken_by_cancel)
 175         && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
 176       THREAD_SETMEM(self, p_woken_by_cancel, 0);
 177       __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
 178     }
 179     __pthread_lock(&handle->h_lock, self);
 180   }
 181   /* Get return value */
 182   if (thread_return != NULL) *thread_return = th->p_retval;
 183   __pthread_unlock(&handle->h_lock);
 184   /* Send notification to thread manager */
 185   if (__pthread_manager_request >= 0) {
 186     request.req_thread = self;
 187     request.req_kind = REQ_FREE;
 188     request.req_args.free.thread_id = thread_id;
 189     TEMP_FAILURE_RETRY(write(__pthread_manager_request,
 190                 (char *) &request, sizeof(request)));
 191   }
 192   return 0;
 193 }
 194
 195 int pthread_detach(pthread_t thread_id)
 196 {
 197   int terminated;
 198   struct pthread_request request;
 199   pthread_handle handle = thread_handle(thread_id);
 200   pthread_descr th;
 201
 202   __pthread_lock(&handle->h_lock, NULL);
 203   if (invalid_handle(handle, thread_id)) {
 204     __pthread_unlock(&handle->h_lock);
 205     return ESRCH;
 206   }
 207   th = handle->h_descr;
 208   /* If already detached, error */
 209   if (th->p_detached) {
 210     __pthread_unlock(&handle->h_lock);
 211     return EINVAL;
 212   }
 213   /* If already joining, don't do anything. */
 214   if (th->p_joining != NULL) {
 215     __pthread_unlock(&handle->h_lock);
 216     return 0;
 217   }
 218   /* Mark as detached */
 219   th->p_detached = 1;
 220   terminated = th->p_terminated;
 221   __pthread_unlock(&handle->h_lock);
 222   /* If already terminated, notify thread manager to reclaim resources */
 223   if (terminated && __pthread_manager_request >= 0) {
 224     request.req_thread = thread_self();
 225     request.req_kind = REQ_FREE;
 226     request.req_args.free.thread_id = thread_id;
 227     TEMP_FAILURE_RETRY(write(__pthread_manager_request,
 228                 (char *) &request, sizeof(request)));
 229   }
 230   return 0;
 231 }