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-rw-r--r--htl/pt-dealloc.c68
1 files changed, 68 insertions, 0 deletions
diff --git a/htl/pt-dealloc.c b/htl/pt-dealloc.c
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+/* Deallocate a thread structure.
+ Copyright (C) 2000-2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <assert.h>
+#include <pthread.h>
+#include <stdlib.h>
+
+#include <pt-internal.h>
+
+#include <atomic.h>
+
+/* List of thread structures corresponding to free thread IDs. */
+extern struct __pthread *__pthread_free_threads;
+extern pthread_mutex_t __pthread_free_threads_lock;
+
+
+/* Deallocate the thread structure for PTHREAD. */
+void
+__pthread_dealloc (struct __pthread *pthread)
+{
+ assert (pthread->state != PTHREAD_TERMINATED);
+
+ if (!atomic_decrement_and_test (&pthread->nr_refs))
+ return;
+
+ /* Withdraw this thread from the thread ID lookup table. */
+ __pthread_setid (pthread->thread, NULL);
+
+ /* Mark the thread as terminated. We broadcast the condition
+ here to prevent pthread_join from waiting for this thread to
+ exit where it was never really started. Such a call to
+ pthread_join is completely bogus, but unfortunately allowed
+ by the standards. */
+ __pthread_mutex_lock (&pthread->state_lock);
+ if (pthread->state != PTHREAD_EXITED)
+ __pthread_cond_broadcast (&pthread->state_cond);
+ __pthread_mutex_unlock (&pthread->state_lock);
+
+ /* We do not actually deallocate the thread structure, but add it to
+ a list of re-usable thread structures. */
+ __pthread_mutex_lock (&__pthread_free_threads_lock);
+ __pthread_enqueue (&__pthread_free_threads, pthread);
+ __pthread_mutex_unlock (&__pthread_free_threads_lock);
+
+ /* Setting PTHREAD->STATE to PTHREAD_TERMINATED makes this TCB
+ available for reuse. After that point, we can no longer assume
+ that PTHREAD is valid.
+
+ Note that it is safe to not lock this update to PTHREAD->STATE:
+ the only way that it can now be accessed is in __pthread_alloc,
+ which reads this variable. */
+ pthread->state = PTHREAD_TERMINATED;
+}