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/* 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>
#define __USE_GNU
#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 */
void pthread_exit(void * retval)
{
pthread_descr self = thread_self();
pthread_descr joining;
struct pthread_request request;
PDEBUG("self=%p, pid=%d\n", self, self->p_pid);
/* Reset the cancellation flag to avoid looping if the cleanup handlers
contain cancellation points */
THREAD_SETMEM(self, p_canceled, 0);
/* Call cleanup functions and destroy the thread-specific data */
__pthread_perform_cleanup();
__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(__libc_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)
{
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_exit(PTHREAD_CANCELED);
}
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_exit(PTHREAD_CANCELED);
}
__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(__libc_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(__libc_write(__pthread_manager_request,
(char *) &request, sizeof(request)));
}
return 0;
}
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