1 files changed, 44 insertions, 0 deletions
diff --git a/sysdeps/mach/hurd/pt-rwlock-tryrdlock.c b/sysdeps/mach/hurd/pt-rwlock-tryrdlock.c
new file mode 100644
index 0000000..4ce60e4
--- /dev/null
+++ b/sysdeps/mach/hurd/pt-rwlock-tryrdlock.c
@@ -0,0 +1,44 @@
+/* Copyright (C) 2016 Free Software Foundation, Inc.
+   Contributed by Agustina Arzille <avarzille@riseup.net>, 2016.
+
+   This program 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.
+
+   This program 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 this program; if not, see
+   <http://www.gnu.org/licenses/>.
+*/
+
+#include <pthread.h>
+#include <pt-internal.h>
+#include <bits/pt-atomic.h>
+#include <hurdlock.h>
+#include "pt-rwlock.h"
+
+int pthread_rwlock_tryrdlock (pthread_rwlock_t *rwp)
+{
+  if (rwl_owned_p (rwp, early_pthread_self(), rwp->__flags))
+    return (EDEADLK);
+
+  union __hurd_xint tmp = { atomic_loadx (&rwp->__oid_nrd.__qv) };
+  if ((rwl_oid (tmp) & ID_MASK) == 0 &&
+      catomic_casx_bool (&rwp->__oid_nrd.__qv,
+        hurd_xint_pair (tmp.__lo, tmp.__hi),
+        hurd_xint_pair (RWLOCK_RO, rwl_nrd (tmp) + 1)))
+    {
+      if (rwl_oid (tmp) != RWLOCK_RO && rwl_nrd (tmp) > 0)
+        lll_wake (&rwl_oid(rwp->__oid_nrd), GSYNC_BROADCAST |
+          (rwp->__flags & GSYNC_SHARED));
+
+      return (0);
+    }
+
+  return (EBUSY);
+}