<Hermetic> Implement CPython2 Launcher in C++.
The launcher is actually a wrapper which will statically link Python
interpreter within the .par file. It is used to bootstrap embedded
interpreter.
The next step is to change/integrate with Soong to make this hermetic .par
generation process more automatic.
Bug: b/62380596
Test: The launcher has been tested using real files:
zip -r hermetic.zip entry_point.txt Stdlib/ runfiles/
cat launcher | cat - hermetic.zip > executable && chmod u+x executable
Change-Id: I293cae2fe74d46766044f3e3c4b654a54d319b67
diff --git a/Launcher/launcher_internal.h b/Launcher/launcher_internal.h
new file mode 100644
index 0000000..285176a
--- /dev/null
+++ b/Launcher/launcher_internal.h
@@ -0,0 +1,62 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// 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.
+
+#ifndef ANDROID_CPYTHON2_PYTHON_LAUNCHER_INTERNAL_H
+#define ANDROID_CPYTHON2_PYTHON_LAUNCHER_INTERNAL_H
+
+#include <Python.h>
+
+#include <string>
+
+namespace android {
+namespace cpython2 {
+namespace python_launcher {
+
+namespace internal{
+#define ENTRYPOINT_FILE "entry_point.txt"
+#define RUNFILES "runfiles"
+
+// Use "runpy" module to locate and run Python script using Python module
+// namespace rather than the filesystem.
+// The caller owns "module" pointer, which cannot be NULL.
+int RunModule(const char *module, int set_argv0);
+
+// Get valid entrypoint file path.
+// The caller owns "launcher_path" pointer, which cannot be NULL.
+// Return non-empty string as success. Otherwise, return empty string.
+std::string GetEntryPointFilePath(const char *launcher_path);
+
+// Run the Python script embedded in ENTRYPOINT_FILE.
+// The caller owns "launcher_path" pointer, which cannot be NULL.
+int RunModuleNameFromEntryPoint(const char *launcher_path, std::string entrypoint);
+
+// Add path to Python sys.path list.
+// The caller owns "path" pointer, which cannot be NULL.
+int AddPathToPythonSysPath(const char *path);
+
+// Run __main__ module within the hermetic .par file.
+// The caller owns "launcher_path" pointer, which cannot be NULL.
+// Return 0 as success. Otherwise, return -1.
+int RunMainFromImporter(const char *launcher_path);
+} // namespace internal
+
+// Try to run the Python script embedded in ENTRYPOINT_FILE. Otherwise,
+// run __main__ module as fallback.
+// The caller owns "launcher_path" pointer, which cannot be NULL.
+int RunEntryPointOrMainModule(const char *launcher_path);
+} // namespace python_launcher
+} // namespace cpython2
+} // namespace android
+
+#endif // ANDROID_CPYTHON2_PYTHON_LAUNCHER_INTERNAL_H