1 files changed, 52 insertions, 0 deletions
diff --git a/kern/kmutex.h b/kern/kmutex.h
new file mode 100644
index 00000000..29815156
--- /dev/null
+++ b/kern/kmutex.h
@@ -0,0 +1,52 @@
+/* Copyright (C) 2017 Free Software Foundation, Inc.
+   Contributed by Agustina Arzille <avarzille@riseup.net>, 2017.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public
+   License along with this program; if not, see
+   <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _KERN_KMUTEX_H_
+#define _KERN_KMUTEX_H_   1
+
+#include <kern/lock.h>
+#include <mach/kern_return.h>
+
+struct kmutex
+{
+  unsigned int state;
+  decl_simple_lock_data (, lock)
+};
+
+/* Possible values for the mutex state. */
+#define KMUTEX_AVAIL       0
+#define KMUTEX_LOCKED      1
+#define KMUTEX_CONTENDED   2
+
+/* Initialize mutex in *MTXP. */
+extern void kmutex_init (struct kmutex *mtxp);
+
+/* Acquire lock MTXP. If INTERRUPTIBLE is true, the sleep may be
+ * prematurely terminated, in which case the function returns
+ * KERN_INTERRUPTED. Otherwise, KERN_SUCCESS is returned. */
+extern kern_return_t kmutex_lock (struct kmutex *mtxp,
+  boolean_t interruptible);
+
+/* Try to acquire the lock MTXP without sleeping.
+ * Returns KERN_SUCCESS if successful, KERN_FAILURE otherwise. */
+extern kern_return_t kmutex_trylock (struct kmutex *mtxp);
+
+/* Unlock the mutex MTXP. */
+extern void kmutex_unlock (struct kmutex *mtxp);
+
+#endif