hurd: Add hurd thread library

Contributed by

Agustina Arzille <avarzille@riseup.net>
Amos Jeffries <squid3@treenet.co.nz>
David Michael <fedora.dm0@gmail.com>
Marco Gerards <marco@gnu.org>
Marcus Brinkmann <marcus@gnu.org>
Neal H. Walfield <neal@gnu.org>
Pino Toscano <toscano.pino@tiscali.it>
Richard Braun <rbraun@sceen.net>
Roland McGrath <roland@gnu.org>
Samuel Thibault <samuel.thibault@ens-lyon.org>
Thomas DiModica <ricinwich@yahoo.com>
Thomas Schwinge <tschwinge@gnu.org>

	* htl: New directory.
	* sysdeps/htl: New directory.
	* sysdeps/hurd/htl: New directory.
	* sysdeps/i386/htl: New directory.
	* sysdeps/mach/htl: New directory.
	* sysdeps/mach/hurd/htl: New directory.
	* sysdeps/mach/hurd/i386/htl: New directory.
	* nscd/Depend, resolv/Depend, rt/Depend: Add htl dependency.
	* sysdeps/mach/hurd/i386/Implies: Add mach/hurd/i386/htl imply.
	* sysdeps/mach/hurd/i386/libpthread.abilist: New file.

1 files changed, 68 insertions, 0 deletions

diff --git a/htl/pt-dealloc.c b/htl/pt-dealloc.c
new file mode 100644
index 0000000000..15e251ef46
--- /dev/null
+++ b/htl/pt-dealloc.c
@@ -0,0 +1,68 @@
+/* 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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  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;
+}