Merge tag 'upstream/libpthread/20090404' into upstream-merged

1 files changed, 95 insertions, 0 deletions

diff --git a/libpthread/sysdeps/generic/pt-rwlock-timedwrlock.c b/libpthread/sysdeps/generic/pt-rwlock-timedwrlock.c
new file mode 100644
index 00000000..04eab51f
--- /dev/null
+++ b/libpthread/sysdeps/generic/pt-rwlock-timedwrlock.c
@@ -0,0 +1,95 @@
+/* Acquire a rwlock for writing.  Generic version.
+   Copyright (C) 2002, 2005 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,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <pthread.h>
+#include <assert.h>
+
+#include <pt-internal.h>
+
+/* Acquire RWLOCK for writing blocking until *ABSTIME if we cannot get
+   it.  As a special GNU extension, if ABSTIME is NULL then the wait
+   shall not time out.  */
+int
+__pthread_rwlock_timedwrlock_internal (struct __pthread_rwlock *rwlock,
+				       const struct timespec *abstime)
+{
+  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);
+
+      __pthread_spin_unlock (&rwlock->__lock);
+      return 0;
+    }
+
+  /* The lock is busy.  */
+
+  if (abstime && (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000))
+    return EINVAL;
+
+  self = _pthread_self ();
+
+  /* Add ourselves to the queue.  */
+  __pthread_enqueue (&rwlock->writerqueue, self);
+  __pthread_spin_unlock (&rwlock->__lock);
+
+  /* Block the thread.  */
+  if (abstime)
+    {
+      error_t err;
+
+      err = __pthread_timedblock (self, abstime);
+      if (err)
+	/* We timed out.  We may need to disconnect ourself from the
+	   waiter queue.
+
+	   FIXME: What do we do if we get a wakeup message before we
+	   disconnect ourself?  It may remain until the next time we
+	   block.  */
+	{
+	  assert (err == ETIMEDOUT);
+
+	  __pthread_spin_lock (&rwlock->__lock);
+	  if (self->prevp)
+	    /* Disconnect ourself.  */
+	    __pthread_dequeue (self);
+	  __pthread_spin_unlock (&rwlock->__lock);
+
+	  return err;
+	}
+    }
+  else
+    __pthread_block (self);
+
+  assert (rwlock->readers == 0);
+
+  return 0;
+}
+
+int
+pthread_rwlock_timedwrlock (struct __pthread_rwlock *rwlock,
+			    const struct timespec *abstime)
+{
+  return __pthread_rwlock_timedwrlock_internal (rwlock, abstime);
+}