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, 177 insertions, 0 deletions

diff --git a/sysdeps/htl/pt-cond-timedwait.c b/sysdeps/htl/pt-cond-timedwait.c
new file mode 100644
index 0000000000..525e63dd42
--- /dev/null
+++ b/sysdeps/htl/pt-cond-timedwait.c
@@ -0,0 +1,177 @@
+/* Wait on a condition.  Generic version.
+   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 <pthread.h>
+
+#include <pt-internal.h>
+
+extern int __pthread_cond_timedwait_internal (pthread_cond_t *cond,
+					      pthread_mutex_t *mutex,
+					      const struct timespec *abstime);
+
+int
+__pthread_cond_timedwait (pthread_cond_t *cond,
+			  pthread_mutex_t *mutex,
+			  const struct timespec *abstime)
+{
+  return __pthread_cond_timedwait_internal (cond, mutex, abstime);
+}
+
+strong_alias (__pthread_cond_timedwait, pthread_cond_timedwait);
+
+struct cancel_ctx
+{
+  struct __pthread *wakeup;
+  pthread_cond_t *cond;
+};
+
+static void
+cancel_hook (void *arg)
+{
+  struct cancel_ctx *ctx = arg;
+  struct __pthread *wakeup = ctx->wakeup;
+  pthread_cond_t *cond = ctx->cond;
+  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 = wakeup->prevp != NULL;
+  if (unblock)
+    __pthread_dequeue (wakeup);
+  __pthread_spin_unlock (&cond->__lock);
+
+  if (unblock)
+    __pthread_wakeup (wakeup);
+}
+
+/* Block on condition variable COND until ABSTIME.  As a GNU
+   extension, if ABSTIME is NULL, then wait forever.  MUTEX should be
+   held by the calling thread.  On return, MUTEX will be held by the
+   calling thread.  */
+int
+__pthread_cond_timedwait_internal (pthread_cond_t *cond,
+				   pthread_mutex_t *mutex,
+				   const struct timespec *abstime)
+{
+  error_t err;
+  int cancelled, oldtype, drain;
+  clockid_t clock_id = __pthread_default_condattr.__clock;
+
+  if (abstime && (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000))
+    return EINVAL;
+
+  struct __pthread *self = _pthread_self ();
+  struct cancel_ctx ctx;
+  ctx.wakeup = self;
+  ctx.cond = cond;
+
+  /* Test for a pending cancellation request, switch to deferred mode for
+     safer resource handling, and prepare the hook to call in case we're
+     cancelled while blocking.  Once CANCEL_LOCK is released, the cancellation
+     hook can be called by another thread at any time.  Whatever happens,
+     this function must exit with MUTEX locked.
+
+     This function contains inline implementations of pthread_testcancel and
+     pthread_setcanceltype to reduce locking overhead.  */
+  __pthread_mutex_lock (&self->cancel_lock);
+  cancelled = (self->cancel_state == PTHREAD_CANCEL_ENABLE)
+      && self->cancel_pending;
+
+  if (!cancelled)
+    {
+      self->cancel_hook = cancel_hook;
+      self->cancel_hook_arg = &ctx;
+      oldtype = self->cancel_type;
+
+      if (oldtype != PTHREAD_CANCEL_DEFERRED)
+	self->cancel_type = PTHREAD_CANCEL_DEFERRED;
+
+      /* Add ourselves to the list of waiters.  This is done while setting
+         the cancellation hook to simplify the cancellation procedure, i.e.
+         if the thread is queued, it can be cancelled, otherwise it is
+         already unblocked, progressing on the return path.  */
+      __pthread_spin_lock (&cond->__lock);
+      __pthread_enqueue (&cond->__queue, self);
+      if (cond->__attr != NULL)
+	clock_id = cond->__attr->__clock;
+      __pthread_spin_unlock (&cond->__lock);
+    }
+  __pthread_mutex_unlock (&self->cancel_lock);
+
+  if (cancelled)
+    pthread_exit (PTHREAD_CANCELED);
+
+  /* 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);
+    }
+
+  __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.  */
+      if (!err)
+	drain = 0;
+      else
+	{
+	  assert (err == ETIMEDOUT);
+	  drain = 1;
+	}
+    }
+  else
+    {
+      /* We're still in the list of waiters.  Noone attempted to wake us up,
+         i.e. we timed out.  */
+      assert (err == ETIMEDOUT);
+      __pthread_dequeue (self);
+      drain = 0;
+    }
+  __pthread_spin_unlock (&cond->__lock);
+
+  if (drain)
+    __pthread_block (self);
+
+  /* We're almost done.  Remove the unblock hook, restore the previous
+     cancellation type, and check for a pending cancellation request.  */
+  __pthread_mutex_lock (&self->cancel_lock);
+  self->cancel_hook = NULL;
+  self->cancel_hook_arg = NULL;
+  self->cancel_type = oldtype;
+  cancelled = (self->cancel_state == PTHREAD_CANCEL_ENABLE)
+      && self->cancel_pending;
+  __pthread_mutex_unlock (&self->cancel_lock);
+
+  /* Reacquire MUTEX before returning/cancelling.  */
+  __pthread_mutex_lock (mutex);
+
+  if (cancelled)
+    pthread_exit (PTHREAD_CANCELED);
+
+  return err;
+}