/* Linuxthreads - a simple clone()-based implementation of Posix */ /* threads for Linux. */ /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */ /* */ /* This program is free software; you can redistribute it and/or */ /* modify it under the terms of the GNU Library General Public License */ /* as published by the Free Software Foundation; either version 2 */ /* of the License, or (at your option) any later version. */ /* */ /* This program is distributed in the hope that it will be useful, */ /* but WITHOUT ANY WARRANTY; without even the implied warranty of */ /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */ /* GNU Library General Public License for more details. */ /* Thread termination and joining */ #include <features.h> #include <errno.h> #include <sched.h> #include <unistd.h> #include <stdlib.h> #include "pthread.h" #include "internals.h" #include "spinlock.h" #include "restart.h" #include "debug.h" /* PDEBUG, added by StS */ libpthread_hidden_proto(pthread_exit) void pthread_exit(void * retval) { __pthread_do_exit (retval, CURRENT_STACK_FRAME); } libpthread_hidden_def (pthread_exit) void __pthread_do_exit(void *retval, char *currentframe) { pthread_descr self = thread_self(); pthread_descr joining; struct pthread_request request; PDEBUG("self=%p, pid=%d\n", self, self->p_pid); /* obey POSIX behavior and prevent cancellation functions from * being called more than once. * http://sourceware.org/ml/libc-ports/2006-10/msg00043.html */ THREAD_SETMEM(self, p_cancelstate, PTHREAD_CANCEL_DISABLE); THREAD_SETMEM(self, p_canceltype, PTHREAD_CANCEL_DEFERRED); /* Call cleanup functions and destroy the thread-specific data */ __pthread_perform_cleanup(currentframe); __pthread_destroy_specifics(); /* Store return value */ __pthread_lock(THREAD_GETMEM(self, p_lock), self); THREAD_SETMEM(self, p_retval, retval); /* See whether we have to signal the death. */ if (THREAD_GETMEM(self, p_report_events)) { /* See whether TD_DEATH is in any of the mask. */ int idx = __td_eventword (TD_DEATH); uint32_t mask = __td_eventmask (TD_DEATH); if ((mask & (__pthread_threads_events.event_bits[idx] | THREAD_GETMEM_NC(self, p_eventbuf.eventmask).event_bits[idx])) != 0) { /* Yep, we have to signal the death. */ THREAD_SETMEM(self, p_eventbuf.eventnum, TD_DEATH); THREAD_SETMEM(self, p_eventbuf.eventdata, self); __pthread_last_event = self; /* Now call the function to signal the event. */ __linuxthreads_death_event(); } } /* Say that we've terminated */ THREAD_SETMEM(self, p_terminated, 1); /* See if someone is joining on us */ joining = THREAD_GETMEM(self, p_joining); PDEBUG("joining = %p, pid=%d\n", joining, joining->p_pid); __pthread_unlock(THREAD_GETMEM(self, p_lock)); /* Restart joining thread if any */ if (joining != NULL) restart(joining); /* If this is the initial thread, block until all threads have terminated. If another thread calls exit, we'll be terminated from our signal handler. */ if (self == __pthread_main_thread && __pthread_manager_request >= 0) { request.req_thread = self; request.req_kind = REQ_MAIN_THREAD_EXIT; TEMP_FAILURE_RETRY(write(__pthread_manager_request, (char *)&request, sizeof(request))); suspend(self); /* Main thread flushes stdio streams and runs atexit functions. * It also calls a handler within LinuxThreads which sends a process exit * request to the thread manager. */ exit(0); } /* Exit the process (but don't flush stdio streams, and don't run atexit functions). */ _exit(0); } /* Function called by pthread_cancel to remove the thread from waiting on a condition variable queue. */ static int join_extricate_func(void *obj, pthread_descr th attribute_unused) { volatile pthread_descr self = thread_self(); pthread_handle handle = obj; pthread_descr jo; int did_remove = 0; __pthread_lock(&handle->h_lock, self); jo = handle->h_descr; did_remove = jo->p_joining != NULL; jo->p_joining = NULL; __pthread_unlock(&handle->h_lock); return did_remove; } int pthread_join(pthread_t thread_id, void ** thread_return) { volatile pthread_descr self = thread_self(); struct pthread_request request; pthread_handle handle = thread_handle(thread_id); pthread_descr th; pthread_extricate_if extr; int already_canceled = 0; PDEBUG("\n"); /* Set up extrication interface */ extr.pu_object = handle; extr.pu_extricate_func = join_extricate_func; __pthread_lock(&handle->h_lock, self); if (invalid_handle(handle, thread_id)) { __pthread_unlock(&handle->h_lock); return ESRCH; } th = handle->h_descr; if (th == self) { __pthread_unlock(&handle->h_lock); return EDEADLK; } /* If detached or already joined, error */ if (th->p_detached || th->p_joining != NULL) { __pthread_unlock(&handle->h_lock); return EINVAL; } /* If not terminated yet, suspend ourselves. */ if (! th->p_terminated) { /* Register extrication interface */ __pthread_set_own_extricate_if(self, &extr); if (!(THREAD_GETMEM(self, p_canceled) && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE)) th->p_joining = self; else already_canceled = 1; __pthread_unlock(&handle->h_lock); if (already_canceled) { __pthread_set_own_extricate_if(self, 0); __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME); } PDEBUG("before suspend\n"); suspend(self); PDEBUG("after suspend\n"); /* Deregister extrication interface */ __pthread_set_own_extricate_if(self, 0); /* This is a cancellation point */ if (THREAD_GETMEM(self, p_woken_by_cancel) && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) { THREAD_SETMEM(self, p_woken_by_cancel, 0); __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME); } __pthread_lock(&handle->h_lock, self); } /* Get return value */ if (thread_return != NULL) *thread_return = th->p_retval; __pthread_unlock(&handle->h_lock); /* Send notification to thread manager */ if (__pthread_manager_request >= 0) { request.req_thread = self; request.req_kind = REQ_FREE; request.req_args.free.thread_id = thread_id; TEMP_FAILURE_RETRY(write(__pthread_manager_request, (char *) &request, sizeof(request))); } return 0; } int pthread_detach(pthread_t thread_id) { int terminated; struct pthread_request request; pthread_handle handle = thread_handle(thread_id); pthread_descr th; __pthread_lock(&handle->h_lock, NULL); if (invalid_handle(handle, thread_id)) { __pthread_unlock(&handle->h_lock); return ESRCH; } th = handle->h_descr; /* If already detached, error */ if (th->p_detached) { __pthread_unlock(&handle->h_lock); return EINVAL; } /* If already joining, don't do anything. */ if (th->p_joining != NULL) { __pthread_unlock(&handle->h_lock); return 0; } /* Mark as detached */ th->p_detached = 1; terminated = th->p_terminated; __pthread_unlock(&handle->h_lock); /* If already terminated, notify thread manager to reclaim resources */ if (terminated && __pthread_manager_request >= 0) { request.req_thread = thread_self(); request.req_kind = REQ_FREE; request.req_args.free.thread_id = thread_id; TEMP_FAILURE_RETRY(write(__pthread_manager_request, (char *) &request, sizeof(request))); } return 0; }