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, 169 insertions, 0 deletions

diff --git a/sysdeps/mach/hurd/htl/pt-hurd-cond-timedwait.c b/sysdeps/mach/hurd/htl/pt-hurd-cond-timedwait.c
new file mode 100644
index 0000000000..41792e3711
--- /dev/null
+++ b/sysdeps/mach/hurd/htl/pt-hurd-cond-timedwait.c
@@ -0,0 +1,169 @@
+/* pthread_hurd_cond_timedwait_np.  Hurd-specific wait on a condition.
+   Copyright (C) 2012-2018 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 <pthread.h>
+#include <assert.h>
+#include <hurd/signal.h>
+
+#include <pt-internal.h>
+
+extern int __pthread_hurd_cond_timedwait_internal (pthread_cond_t *cond,
+						   pthread_mutex_t *mutex,
+						   const struct timespec
+						   *abstime);
+
+int
+__pthread_hurd_cond_timedwait_np (pthread_cond_t *cond,
+				  pthread_mutex_t *mutex,
+				  const struct timespec *abstime)
+{
+  return __pthread_hurd_cond_timedwait_internal (cond, mutex, abstime);
+}
+
+strong_alias (__pthread_hurd_cond_timedwait_np, pthread_hurd_cond_timedwait_np);
+
+int
+__pthread_hurd_cond_timedwait_internal (pthread_cond_t *cond,
+					pthread_mutex_t *mutex,
+					const struct timespec *abstime)
+{
+  struct hurd_sigstate *ss = _hurd_self_sigstate ();
+  struct __pthread *self = _pthread_self ();
+  error_t err = 0;
+  int cancel, drain;
+  clockid_t clock_id = __pthread_default_condattr.__clock;
+
+  /* This function will be called by hurd_thread_cancel while we are blocked
+     We wake up our thread if it's still blocking or about to block, so it will
+     progress and notice the cancellation flag.  */
+  void cancel_me (void)
+  {
+    int unblock;
+
+    __pthread_spin_lock (&cond->__lock);
+    /* The thread only needs to be awaken if it's blocking or about to block.
+       If it was already unblocked, it's not queued any more.  */
+    unblock = self->prevp != NULL;
+    if (unblock)
+      __pthread_dequeue (self);
+    __pthread_spin_unlock (&cond->__lock);
+
+    if (unblock)
+      __pthread_wakeup (self);
+  }
+
+  assert (ss->intr_port == MACH_PORT_NULL);	/* Sanity check for signal bugs. */
+
+  if (abstime != NULL && (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000))
+    return EINVAL;
+
+  /* Atomically enqueue our thread on the condition variable's queue of
+     waiters, and mark our sigstate to indicate that `cancel_me' must be
+     called to wake us up.  We must hold the sigstate lock while acquiring
+     the condition variable's lock and tweaking it, so that
+     hurd_thread_cancel can never suspend us and then deadlock waiting for
+     the condition variable's lock.  */
+
+  __spin_lock (&ss->lock);
+  __pthread_spin_lock (&cond->__lock);
+  cancel = ss->cancel;
+  if (cancel)
+    /* We were cancelled before doing anything.  Don't block at all.  */
+    ss->cancel = 0;
+  else
+    {
+      /* Put us on the queue so that pthread_cond_broadcast will know to wake
+         us up.  */
+      __pthread_enqueue (&cond->__queue, self);
+      if (cond->__attr)
+	clock_id = cond->__attr->__clock;
+      /* Tell hurd_thread_cancel how to unblock us.  */
+      ss->cancel_hook = &cancel_me;
+    }
+  __pthread_spin_unlock (&cond->__lock);
+  __spin_unlock (&ss->lock);
+
+  if (cancel)
+    {
+      /* Cancelled on entry.  Just leave the mutex locked.  */
+      mutex = NULL;
+
+      __spin_lock (&ss->lock);
+    }
+  else
+    {
+      /* Release MUTEX before blocking.  */
+      __pthread_mutex_unlock (mutex);
+
+      /* Block the thread.  */
+      if (abstime != NULL)
+	err = __pthread_timedblock (self, abstime, clock_id);
+      else
+	{
+	  err = 0;
+	  __pthread_block (self);
+	}
+
+      /* As it was done when enqueueing, prevent hurd_thread_cancel from
+         suspending us while the condition lock is held.  */
+      __spin_lock (&ss->lock);
+      __pthread_spin_lock (&cond->__lock);
+      if (self->prevp == NULL)
+	/* Another thread removed us from the list of waiters, which means
+	   a wakeup message has been sent.  It was either consumed while
+	   we were blocking, or queued after we timed out and before we
+	   acquired the condition lock, in which case the message queue
+	   must be drained.  */
+	drain = err ? 1 : 0;
+      else
+	{
+	  /* We're still in the list of waiters.  Noone attempted to wake us
+	     up, i.e. we timed out.  */
+	  __pthread_dequeue (self);
+	  drain = 0;
+	}
+      __pthread_spin_unlock (&cond->__lock);
+
+      if (drain)
+	__pthread_block (self);
+    }
+
+  /* Clear the hook, now that we are done blocking.  */
+  ss->cancel_hook = NULL;
+  /* Check the cancellation flag; we might have unblocked due to
+     cancellation rather than a normal pthread_cond_signal or
+     pthread_cond_broadcast (or we might have just happened to get cancelled
+     right after waking up).  */
+  cancel |= ss->cancel;
+  ss->cancel = 0;
+  __spin_unlock (&ss->lock);
+
+  if (mutex != NULL)
+    /* Reacquire the mutex and return.  */
+    __pthread_mutex_lock (mutex);
+
+  if (cancel)
+    return EINTR;
+  else if (err)
+    {
+      assert (err == ETIMEDOUT);
+      return err;
+    }
+
+  return 0;
+}