Allow native process to load updatable driver.

Previously an application process can be specified to load the updatable
driver and the driver path will be set up correctly via
GraphicsEnvironment.java.  For a native process that is not an
application process, there's no way for it to be specificed to load the
updatable driver and hence the driver path is not set up. This patch
provides a way for a native process that runs in an environment, for
example shell, where environment variables can be set, to opt into using
udpatable driver by setting UPDATABLE_GFX_DRIVER to 1.

Bug: b/157832445, b/159240322
Test: ./gapit validate_gpu_profiling --os android
Change-Id: I597535caa5ae0a033c2b8d581bb39b14875ac8fc

1 files changed, 29 insertions, 1 deletions

diff --git a/libs/graphicsenv/GraphicsEnv.cpp b/libs/graphicsenv/GraphicsEnv.cpp
index cfc7e98da3..119b3e0b7d 100644
--- a/libs/graphicsenv/GraphicsEnv.cpp
+++ b/libs/graphicsenv/GraphicsEnv.cpp
@@ -39,6 +39,13 @@
 #include <string>
 #include <thread>
 
+// TODO(b/159240322): Extend this to x86 ABI.
+#if defined(__LP64__)
+#define UPDATABLE_DRIVER_ABI "arm64-v8a"
+#else
+#define UPDATABLE_DRIVER_ABI "armeabi-v7a"
+#endif // defined(__LP64__)
+
 // TODO(ianelliott@): Get the following from an ANGLE header:
 #define CURRENT_ANGLE_API_VERSION 2 // Current API verion we are targetting
 // Version-2 API:
@@ -582,7 +589,28 @@ android_namespace_t* GraphicsEnv::getDriverNamespace() {
     }
 
     if (mDriverPath.empty()) {
-        return nullptr;
+        // For an application process, driver path is empty means this application is not opted in
+        // to use updatable driver. Application process doesn't have the ability to set up
+        // environment variables and hence before `getenv` call will return.
+        // For a process that is not an application process, if it's run from an environment,
+        // for example shell, where environment variables can be set, then it can opt into using
+        // udpatable driver by setting UPDATABLE_GFX_DRIVER to 1. By setting to 1 the developer
+        // driver will be used currently.
+        // TODO(b/159240322) Support the production updatable driver.
+        const char* id = getenv("UPDATABLE_GFX_DRIVER");
+        if (id == nullptr || std::strcmp(id, "1")) {
+            return nullptr;
+        }
+        const sp<IGpuService> gpuService = getGpuService();
+        if (!gpuService) {
+            return nullptr;
+        }
+        mDriverPath = gpuService->getUpdatableDriverPath();
+        if (mDriverPath.empty()) {
+            return nullptr;
+        }
+        mDriverPath.append(UPDATABLE_DRIVER_ABI);
+        ALOGI("Driver path is setup via UPDATABLE_GFX_DRIVER: %s", mDriverPath.c_str());
     }
 
     auto vndkNamespace = android_get_exported_namespace("vndk");