Recognise system/system_ext as a system image partition path.

Also move the regex used for that next to the other partition regex'es
for visibility, and add some unit tests.

Test: atest libnativeloader_tests libnativeloader_e2e_tests
  on mokey_go32
Bug: 346515837
Change-Id: I30a85678e0d3c45645d6f089f5f1d92e1360e8bf

libnativeloader/library_namespaces.cpp

@@ -86,6 +86,8 @@ constexpr const char* kProductLibPath = "/product/" LIB ":/system/product/" LIB;
 const std::regex kVendorPathRegex("(/system)?/vendor/.*");
 const std::regex kProductPathRegex("(/system)?/product/.*");
 const std::regex kSystemPathRegex("/system(_ext)?/.*");  // MUST be tested last.
+const std::regex kPartitionNativeLibPathRegex(
+    "/(system|(system/)?(system_ext|vendor|product))/lib(64)?/.*");
 
 jobject GetParentClassLoader(JNIEnv* env, jobject class_loader) {
   jclass class_loader_class = env->FindClass("java/lang/ClassLoader");
@@ -138,6 +140,12 @@ Result<ApiDomain> GetApiDomainFromPathList(const std::string& path_list) {
   return result;
 }
 
+// Returns true if the given path is in a partition-wide native library location,
+// i.e. <partition root>/lib(64).
+bool IsPartitionNativeLibPath(const std::string& path) {
+  return std::regex_match(path, kPartitionNativeLibPathRegex);
+}
+
 void LibraryNamespaces::Initialize() {
   // Once public namespace is initialized there is no
   // point in running this code - it will have no effect

libnativeloader/library_namespaces.h

@@ -58,6 +58,7 @@ using ApiDomain = enum {
 
 ApiDomain GetApiDomainFromPath(const std::string_view path);
 Result<ApiDomain> GetApiDomainFromPathList(const std::string& path_list);
+bool IsPartitionNativeLibPath(const std::string& path);
 
 // LibraryNamespaces is a singleton object that manages NativeLoaderNamespace
 // objects for an app process. Its main job is to create (and configure) a new

libnativeloader/library_namespaces_test.cpp

@@ -98,6 +98,23 @@ TEST(LibraryNamespacesTest, TestGetApiDomainFromPathList) {
   }
 }
 
+TEST(LibraryNamespacesTest, TestIsPartitionNativeLibPath) {
+  EXPECT_TRUE(IsPartitionNativeLibPath("/system/lib/libfoo.so"));
+  EXPECT_TRUE(IsPartitionNativeLibPath("/system/lib64/libfoo.so"));
+  EXPECT_TRUE(IsPartitionNativeLibPath("/system_ext/lib64/libfoo.so"));
+  EXPECT_TRUE(IsPartitionNativeLibPath("/product/lib64/libfoo.so"));
+  EXPECT_TRUE(IsPartitionNativeLibPath("/vendor/lib64/libfoo.so"));
+  EXPECT_TRUE(IsPartitionNativeLibPath("/vendor/lib64/hw/libhw.so"));
+  EXPECT_TRUE(IsPartitionNativeLibPath("/system/system_ext/lib64/libfoo.so"));
+  EXPECT_TRUE(IsPartitionNativeLibPath("/system/product/lib64/libfoo.so"));
+  EXPECT_TRUE(IsPartitionNativeLibPath("/system/vendor/lib64/libfoo.so"));
+
+  EXPECT_FALSE(IsPartitionNativeLibPath("/data/app/~~hash==/myapp-hash==/lib/arm64/libapp.so"));
+  EXPECT_FALSE(
+      IsPartitionNativeLibPath("/system/app/PrintSpooler/lib/arm64/libprintspooler_jni.so"));
+  EXPECT_FALSE(IsPartitionNativeLibPath("/product/app/Camera2/lib/arm64/libjni_jpegutil.so"));
+}
+
 }  // namespace
 }  // namespace nativeloader
 }  // namespace android

libnativeloader/native_loader.cpp

@@ -54,9 +54,6 @@ namespace {
 using ::android::base::Result;
 using ::android::nativeloader::LibraryNamespaces;
 
-const std::regex kPartitionNativeLibPathRegex(
-    "/(system(_ext)?|(system/)?(vendor|product))/lib(64)?/.*");
-
 // NATIVELOADER_DEFAULT_NAMESPACE_LIBS is an environment variable that can be
 // used to list extra libraries (separated by ":") that libnativeloader will
 // load from the default namespace. The libraries must be listed without paths,
@@ -340,10 +337,10 @@ void* OpenNativeLibrary(JNIEnv* env,
   // path, so we don't affect the lookup process for libraries specified by name
   // only.
   if (caller_location != nullptr &&
-      // Check that the library is in the partition-wide native library
-      // location. Apps in the partition may have their own native libraries,
-      // and those should still be loaded with the app's classloader namespace.
-      std::regex_match(path, kPartitionNativeLibPathRegex) &&
+      // Apps in the partition may have their own native libraries which should
+      // be loaded with the app's classloader namespace, so only do this for
+      // libraries in the partition-wide lib(64) directories.
+      nativeloader::IsPartitionNativeLibPath(path) &&
       // Don't do this if the system image is older than V, to avoid any compat
       // issues with apps and shared libs in them.
       android::modules::sdklevel::IsAtLeastV()) {