Add libkeyutils.

Also move init over to it.

Bug: http://b/37991155
Test: builds+boots
Change-Id: I5113a9d96a5ce0a0f3bad71134d6cc4f7b41a57e
diff --git a/libkeyutils/keyutils.cpp b/libkeyutils/keyutils.cpp
new file mode 100644
index 0000000..58a2a17
--- /dev/null
+++ b/libkeyutils/keyutils.cpp
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <keyutils.h>
+
+#include <stdarg.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+// Deliberately not exposed. Callers should use the typed APIs instead.
+static long keyctl(int cmd, ...) {
+  va_list va;
+  va_start(va, cmd);
+  unsigned long arg2 = va_arg(va, unsigned long);
+  unsigned long arg3 = va_arg(va, unsigned long);
+  unsigned long arg4 = va_arg(va, unsigned long);
+  unsigned long arg5 = va_arg(va, unsigned long);
+  va_end(va);
+  return syscall(__NR_keyctl, cmd, arg2, arg3, arg4, arg5);
+}
+
+key_serial_t add_key(const char* type, const char* description, const void* payload,
+                     size_t payload_length, key_serial_t ring_id) {
+  return syscall(__NR_add_key, type, description, payload, payload_length, ring_id);
+}
+
+key_serial_t keyctl_get_keyring_ID(key_serial_t id, int create) {
+  return keyctl(KEYCTL_GET_KEYRING_ID, id, create);
+}
+
+long keyctl_revoke(key_serial_t id) {
+  return keyctl(KEYCTL_REVOKE, id);
+}
+
+long keyctl_search(key_serial_t ring_id, const char* type, const char* description,
+                   key_serial_t dest_ring_id) {
+  return keyctl(KEYCTL_SEARCH, ring_id, type, description, dest_ring_id);
+}
+
+long keyctl_setperm(key_serial_t id, int permissions) {
+  return keyctl(KEYCTL_SETPERM, id, permissions);
+}
+
+long keyctl_unlink(key_serial_t key, key_serial_t keyring) {
+  return keyctl(KEYCTL_UNLINK, key, keyring);
+}