diff --git a/libs/binder/Permission.cpp b/libs/binder/Permission.cpp
new file mode 100644
index 0000000..fd8fe69
--- /dev/null
+++ b/libs/binder/Permission.cpp
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <utils/Log.h>
+#include <binder/IPCThreadState.h>
+#include <binder/IServiceManager.h>
+#include <binder/Permission.h>
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+Permission::Permission(char const* name)
+    : mPermissionName(name), mPid(getpid())
+{
+}
+
+Permission::Permission(const String16& name)
+    : mPermissionName(name), mPid(getpid())
+{
+}
+
+Permission::Permission(const Permission& rhs)
+    : mPermissionName(rhs.mPermissionName),
+    mGranted(rhs.mGranted),
+    mPid(rhs.mPid)
+{
+}
+
+Permission::~Permission()
+{
+}
+
+bool Permission::operator < (const Permission& rhs) const
+{
+    return mPermissionName < rhs.mPermissionName;
+}
+
+bool Permission::checkCalling() const
+{
+    IPCThreadState* ipcState = IPCThreadState::self();
+    pid_t pid = ipcState->getCallingPid();
+    uid_t uid = ipcState->getCallingUid();
+    return doCheckPermission(pid, uid);
+}
+
+bool Permission::check(pid_t pid, uid_t uid) const
+{
+    return doCheckPermission(pid, uid);
+}
+
+bool Permission::doCheckPermission(pid_t pid, uid_t uid) const
+{
+    if ((uid == 0) || (pid == mPid)) {
+        // root and ourselves is always okay
+        return true;
+    } else {
+        // see if we already granted this permission for this uid
+        Mutex::Autolock _l(mLock);
+        if (mGranted.indexOf(uid) >= 0)
+            return true;
+    }
+
+    bool granted = checkPermission(mPermissionName, pid, uid);
+    if (granted) {
+        Mutex::Autolock _l(mLock);
+        // no need to check again, the old item will be replaced if it is
+        // already there.
+        mGranted.add(uid);
+    }
+    return granted;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android