1 files changed, 120 insertions, 0 deletions
diff --git a/sysdeps/htl/pt-rwlock-timedrdlock.c b/sysdeps/htl/pt-rwlock-timedrdlock.c
new file mode 100644
index 0000000000..82ae89296c
--- /dev/null
+++ b/sysdeps/htl/pt-rwlock-timedrdlock.c
@@ -0,0 +1,120 @@
+/* Acquire a rwlock for reading.  Generic version.
+   Copyright (C) 2002-2018 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 <pthread.h>
+#include <assert.h>
+
+#include <pt-internal.h>
+
+/* Acquire the rwlock *RWLOCK for reading blocking until *ABSTIME if
+   it is already held.  As a GNU extension, if TIMESPEC is NULL then
+   wait forever.  */
+int
+__pthread_rwlock_timedrdlock_internal (struct __pthread_rwlock *rwlock,
+				       const struct timespec *abstime)
+{
+  error_t err;
+  int drain;
+  struct __pthread *self;
+
+  __pthread_spin_lock (&rwlock->__lock);
+  if (__pthread_spin_trylock (&rwlock->__held) == 0)
+    /* Successfully acquired the lock.  */
+    {
+      assert (rwlock->__readerqueue == 0);
+      assert (rwlock->__writerqueue == 0);
+      assert (rwlock->__readers == 0);
+
+      rwlock->__readers = 1;
+      __pthread_spin_unlock (&rwlock->__lock);
+      return 0;
+    }
+  else
+    /* Lock is held, but is held by a reader?  */
+  if (rwlock->__readers > 0)
+    /* Just add ourself to number of readers.  */
+    {
+      assert (rwlock->__readerqueue == 0);
+      rwlock->__readers++;
+      __pthread_spin_unlock (&rwlock->__lock);
+      return 0;
+    }
+
+  /* The lock is busy.  */
+
+  /* Better be blocked by a writer.  */
+  assert (rwlock->__readers == 0);
+
+  if (abstime != NULL && (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000))
+    return EINVAL;
+
+  self = _pthread_self ();
+
+  /* Add ourself to the queue.  */
+  __pthread_enqueue (&rwlock->__readerqueue, self);
+  __pthread_spin_unlock (&rwlock->__lock);
+
+  /* Block the thread.  */
+  if (abstime != NULL)
+    err = __pthread_timedblock (self, abstime, CLOCK_REALTIME);
+  else
+    {
+      err = 0;
+      __pthread_block (self);
+    }
+
+  __pthread_spin_lock (&rwlock->__lock);
+  if (self->prevp == NULL)
+    /* Another thread removed us from the queue, 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 rwlock lock, in
+       which case the message queue must be drained.  */
+    drain = err ? 1 : 0;
+  else
+    {
+      /* We're still in the queue.  Noone attempted to wake us up, i.e. we
+         timed out.  */
+      __pthread_dequeue (self);
+      drain = 0;
+    }
+  __pthread_spin_unlock (&rwlock->__lock);
+
+  if (drain)
+    __pthread_block (self);
+
+  if (err)
+    {
+      assert (err == ETIMEDOUT);
+      return err;
+    }
+
+  /* The reader count has already been increment by whoever woke us
+     up.  */
+
+  assert (rwlock->__readers > 0);
+
+  return 0;
+}
+
+int
+__pthread_rwlock_timedrdlock (struct __pthread_rwlock *rwlock,
+			      const struct timespec *abstime)
+{
+  return __pthread_rwlock_timedrdlock_internal (rwlock, abstime);
+}
+weak_alias (__pthread_rwlock_timedrdlock, pthread_rwlock_timedrdlock)