1 files changed, 79 insertions, 0 deletions
diff --git a/init/selabel.cpp b/init/selabel.cpp
new file mode 100644
index 000000000..daeb83261
--- /dev/null
+++ b/init/selabel.cpp
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2019 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 "selabel.h"
+
+#include <selinux/android.h>
+
+namespace android {
+namespace init {
+
+namespace {
+
+selabel_handle* sehandle = nullptr;
+}
+
+// selinux_android_file_context_handle() takes on the order of 10+ms to run, so we want to cache
+// its value.  selinux_android_restorecon() also needs an sehandle for file context look up.  It
+// will create and store its own copy, but selinux_android_set_sehandle() can be used to provide
+// one, thus eliminating an extra call to selinux_android_file_context_handle().
+void SelabelInitialize() {
+    sehandle = selinux_android_file_context_handle();
+    selinux_android_set_sehandle(sehandle);
+}
+
+// A C++ wrapper around selabel_lookup() using the cached sehandle.
+// If sehandle is null, this returns success with an empty context.
+bool SelabelLookupFileContext(const std::string& key, int type, std::string* result) {
+    result->clear();
+
+    if (!sehandle) return true;
+
+    char* context;
+    if (selabel_lookup(sehandle, &context, key.c_str(), type) != 0) {
+        return false;
+    }
+    *result = context;
+    free(context);
+    return true;
+}
+
+// A C++ wrapper around selabel_lookup_best_match() using the cached sehandle.
+// If sehandle is null, this returns success with an empty context.
+bool SelabelLookupFileContextBestMatch(const std::string& key,
+                                       const std::vector<std::string>& aliases, int type,
+                                       std::string* result) {
+    result->clear();
+
+    if (!sehandle) return true;
+
+    std::vector<const char*> c_aliases;
+    for (const auto& alias : aliases) {
+        c_aliases.emplace_back(alias.c_str());
+    }
+    c_aliases.emplace_back(nullptr);
+
+    char* context;
+    if (selabel_lookup_best_match(sehandle, &context, key.c_str(), &c_aliases[0], type) != 0) {
+        return false;
+    }
+    *result = context;
+    free(context);
+    return true;
+}
+
+}  // namespace init
+}  // namespace android