Reland: Fix libnativeloader to correctly link to the platform namespace.

This relands http://r.android.com/951440:

This affected binaries in the Runtime APEX, where the platform namespace is
"platform" rather than "default".

Also extend ANDROID_ADDITIONAL_PUBLIC_LIBRARIES to create links to both to
platform and runtime namespaces, so that it can be used to open up access to
internal libraries in the Runtime APEX as well, which is used by ART gtests
and run tests.

Also update some comments in the ld.config*.txt files to accurately explain
why some namespaces need to be visible, and some other minor changes for
consistency. There are no semantically significant changes in those files.

Test: Flash and boot
Test: Run an ART run test with the internal libarttest.so library
Test: lunch aosp_cf_x86_phone-eng;
  atest android.compilation.cts.AdbRootDependentCompilationTest#testCompile_curProfile \
    com.android.cts.dexmetadata.InstallDexMetadataHostTest#testProfileSnapshotAfterInstall \
    installd_dexopt_test
Bug: 130293232
Bug: 121117762
Change-Id: I3d9f2102a03e83843e15bc78b5ad347220c52769
diff --git a/libnativeloader/native_loader.cpp b/libnativeloader/native_loader.cpp
index e460b1a..1012ea0 100644
--- a/libnativeloader/native_loader.cpp
+++ b/libnativeloader/native_loader.cpp
@@ -126,7 +126,7 @@
 // classloader, the classloader-namespace namespace associated with that
 // classloader is selected for dlopen. The namespace is configured so that its
 // search path is set to the app-local JNI directory and it is linked to the
-// default namespace with the names of libs listed in the public.libraries.txt.
+// platform namespace with the names of libs listed in the public.libraries.txt.
 // This way an app can only load its own JNI libraries along with the public libs.
 static constexpr const char* kClassloaderNamespaceName = "classloader-namespace";
 // Same thing for vendor APKs.
@@ -309,21 +309,24 @@
       }
     }
 
-    std::string runtime_exposed_libraries = base::Join(kRuntimePublicLibraries, ":");
+    std::string runtime_exposed_libraries = runtime_public_libraries_;
 
     NativeLoaderNamespace native_loader_ns;
     if (!is_native_bridge) {
+      // The platform namespace is called "default" for binaries in /system and
+      // "platform" for those in the Runtime APEX. Try "platform" first since
+      // "default" always exists.
+      android_namespace_t* platform_ns = android_get_exported_namespace(kPlatformNamespaceName);
+      if (platform_ns == nullptr) {
+        platform_ns = android_get_exported_namespace(kDefaultNamespaceName);
+      }
+
       android_namespace_t* android_parent_ns;
       if (parent_ns != nullptr) {
         android_parent_ns = parent_ns->get_android_ns();
       } else {
-        // Fall back to the platform namespace if no parent is found. It is
-        // called "default" for binaries in /system and "platform" for those in
-        // the Runtime APEX. Try "platform" first since "default" always exists.
-        android_parent_ns = android_get_exported_namespace(kPlatformNamespaceName);
-        if (android_parent_ns == nullptr) {
-          android_parent_ns = android_get_exported_namespace(kDefaultNamespaceName);
-        }
+        // Fall back to the platform namespace if no parent is found.
+        android_parent_ns = platform_ns;
       }
 
       android_namespace_t* ns = android_create_namespace(namespace_name,
@@ -344,7 +347,7 @@
 
       android_namespace_t* runtime_ns = android_get_exported_namespace(kRuntimeNamespaceName);
 
-      if (!android_link_namespaces(ns, nullptr, system_exposed_libraries.c_str())) {
+      if (!android_link_namespaces(ns, platform_ns, system_exposed_libraries.c_str())) {
         *error_msg = dlerror();
         return nullptr;
       }
@@ -374,14 +377,19 @@
 
       native_loader_ns = NativeLoaderNamespace(ns);
     } else {
+      // Same functionality as in the branch above, but calling through native bridge.
+
+      native_bridge_namespace_t* platform_ns =
+          NativeBridgeGetExportedNamespace(kPlatformNamespaceName);
+      if (platform_ns == nullptr) {
+        platform_ns = NativeBridgeGetExportedNamespace(kDefaultNamespaceName);
+      }
+
       native_bridge_namespace_t* native_bridge_parent_namespace;
       if (parent_ns != nullptr) {
         native_bridge_parent_namespace = parent_ns->get_native_bridge_ns();
       } else {
-        native_bridge_parent_namespace = NativeBridgeGetExportedNamespace(kPlatformNamespaceName);
-        if (native_bridge_parent_namespace == nullptr) {
-          native_bridge_parent_namespace = NativeBridgeGetExportedNamespace(kDefaultNamespaceName);
-        }
+        native_bridge_parent_namespace = platform_ns;
       }
 
       native_bridge_namespace_t* ns = NativeBridgeCreateNamespace(namespace_name,
@@ -399,7 +407,7 @@
       native_bridge_namespace_t* runtime_ns =
           NativeBridgeGetExportedNamespace(kRuntimeNamespaceName);
 
-      if (!NativeBridgeLinkNamespaces(ns, nullptr, system_exposed_libraries.c_str())) {
+      if (!NativeBridgeLinkNamespaces(ns, platform_ns, system_exposed_libraries.c_str())) {
         *error_msg = NativeBridgeGetError();
         return nullptr;
       }
@@ -451,6 +459,7 @@
     std::string root_dir = android_root_env != nullptr ? android_root_env : "/system";
     std::string public_native_libraries_system_config =
             root_dir + kPublicNativeLibrariesSystemConfigPathFromRoot;
+    std::string runtime_public_libraries = base::Join(kRuntimePublicLibraries, ":");
     std::string llndk_native_libraries_system_config =
             root_dir + kLlndkNativeLibrariesSystemConfigPathFromRoot;
     std::string vndksp_native_libraries_system_config =
@@ -472,6 +481,10 @@
         std::vector<std::string> additional_libs_vector = base::Split(additional_libs, ":");
         std::copy(additional_libs_vector.begin(), additional_libs_vector.end(),
                   std::back_inserter(sonames));
+        // Apply the same list to the runtime namespace, since some libraries
+        // might reside there.
+        CHECK(sizeof(kRuntimePublicLibraries) > 0);
+        runtime_public_libraries = runtime_public_libraries + ':' + additional_libs;
       }
     }
 
@@ -497,6 +510,7 @@
     }
 
     system_public_libraries_ = base::Join(sonames, ':');
+    runtime_public_libraries_ = runtime_public_libraries;
 
     // read /system/etc/public.libraries-<companyname>.txt which contain partner defined
     // system libs that are exposed to apps. The libs in the txt files must be
@@ -724,6 +738,7 @@
   bool initialized_;
   std::list<std::pair<jweak, NativeLoaderNamespace>> namespaces_;
   std::string system_public_libraries_;
+  std::string runtime_public_libraries_;
   std::string vendor_public_libraries_;
   std::string oem_public_libraries_;
   std::string product_public_libraries_;
diff --git a/rootdir/etc/ld.config.legacy.txt b/rootdir/etc/ld.config.legacy.txt
index 485bc75..4b07478 100644
--- a/rootdir/etc/ld.config.legacy.txt
+++ b/rootdir/etc/ld.config.legacy.txt
@@ -20,6 +20,9 @@
 
 [legacy]
 namespace.default.isolated = false
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
+namespace.default.visible = true
 
 namespace.default.search.paths  = /system/${LIB}
 namespace.default.search.paths += /product/${LIB}
@@ -41,7 +44,7 @@
 
 additional.namespaces = runtime,conscrypt,media,resolv
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
+# Keep in sync with the "platform" namespace in art/build/apex/ld.config.txt.
 # If a shared library or an executable requests a shared library that
 # cannot be loaded into the default namespace, the dynamic linker tries
 # to load the shared library from the runtime namespace. And then, if the
@@ -50,9 +53,6 @@
 # Finally, if all attempts fail, the dynamic linker returns an error.
 namespace.default.links = runtime,resolv
 namespace.default.asan.links = runtime,resolv
-# Visible because some libraries are dlopen'ed, e.g. libopenjdk is dlopen'ed by
-# libart.
-namespace.default.visible = true
 namespace.default.link.runtime.shared_libs  = libandroidicu.so
 namespace.default.link.runtime.shared_libs += libdexfile_external.so
 namespace.default.link.runtime.shared_libs += libdexfiled_external.so
@@ -72,11 +72,13 @@
 # "runtime" APEX namespace
 #
 # This namespace exposes externally accessible libraries from the Runtime APEX.
+# Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.runtime.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.runtime.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.asan.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.links = default
@@ -120,11 +122,11 @@
 # "conscrypt" APEX namespace
 #
 # This namespace is for libraries within the conscrypt APEX.
+# Keep in sync with the "conscrypt" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.conscrypt.isolated = true
 namespace.conscrypt.visible = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.conscrypt.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.asan.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.links = runtime,default
diff --git a/rootdir/etc/ld.config.txt b/rootdir/etc/ld.config.txt
index 264fbf4..f4710d8 100644
--- a/rootdir/etc/ld.config.txt
+++ b/rootdir/etc/ld.config.txt
@@ -43,6 +43,9 @@
 # can't be loaded in this namespace.
 ###############################################################################
 namespace.default.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
+namespace.default.visible = true
 
 namespace.default.search.paths  = /system/${LIB}
 namespace.default.search.paths += /%PRODUCT%/${LIB}
@@ -121,7 +124,7 @@
 namespace.default.asan.permitted.paths += /apex/com.android.runtime/${LIB}/bionic
 namespace.default.asan.permitted.paths += /system/${LIB}/bootstrap
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
+# Keep in sync with the "platform" namespace in art/build/apex/ld.config.txt.
 # If a shared library or an executable requests a shared library that
 # cannot be loaded into the default namespace, the dynamic linker tries
 # to load the shared library from the runtime namespace. And then, if the
@@ -129,9 +132,6 @@
 # dynamic linker tries to load the shared library from the resolv namespace.
 # Finally, if all attempts fail, the dynamic linker returns an error.
 namespace.default.links = runtime,resolv
-# Visible because some libraries are dlopen'ed, e.g. libopenjdk is dlopen'ed by
-# libart.
-namespace.default.visible = true
 namespace.default.link.runtime.shared_libs  = libandroidicu.so
 namespace.default.link.runtime.shared_libs += libdexfile_external.so
 namespace.default.link.runtime.shared_libs += libdexfiled_external.so
@@ -151,11 +151,13 @@
 # "runtime" APEX namespace
 #
 # This namespace exposes externally accessible libraries from the Runtime APEX.
+# Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.runtime.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.runtime.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.asan.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.links = default
@@ -188,11 +190,11 @@
 # "conscrypt" APEX namespace
 #
 # This namespace is for libraries within the conscrypt APEX.
+# Keep in sync with the "conscrypt" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.conscrypt.isolated = true
 namespace.conscrypt.visible = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.conscrypt.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.asan.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.links = runtime,default
@@ -235,6 +237,8 @@
 # Note that there is no link from the default namespace to this namespace.
 ###############################################################################
 namespace.sphal.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
 namespace.sphal.visible = true
 
 namespace.sphal.search.paths  = /odm/${LIB}
@@ -324,6 +328,8 @@
 # This namespace is exclusively for vndk-sp libs.
 ###############################################################################
 namespace.vndk.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
 namespace.vndk.visible = true
 
 namespace.vndk.search.paths  = /odm/${LIB}/vndk-sp
@@ -431,10 +437,10 @@
 # "runtime" APEX namespace
 #
 # This namespace exposes externally accessible libraries from the Runtime APEX.
+# Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.runtime.isolated = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.runtime.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.asan.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.links = system
@@ -566,6 +572,10 @@
 [unrestricted]
 additional.namespaces = runtime,media,conscrypt,resolv
 
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
+namespace.default.visible = true
+
 namespace.default.search.paths  = /system/${LIB}
 namespace.default.search.paths += /odm/${LIB}
 namespace.default.search.paths += /vendor/${LIB}
@@ -577,10 +587,8 @@
 namespace.default.asan.search.paths += /data/asan/vendor/${LIB}
 namespace.default.asan.search.paths +=           /vendor/${LIB}
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
+# Keep in sync with the "platform" namespace in art/build/apex/ld.config.txt.
 namespace.default.links = runtime,resolv
-namespace.default.visible = true
-
 namespace.default.link.runtime.shared_libs  = libandroidicu.so
 namespace.default.link.runtime.shared_libs += libdexfile_external.so
 namespace.default.link.runtime.shared_libs += libdexfiled_external.so
@@ -597,11 +605,13 @@
 # "runtime" APEX namespace
 #
 # This namespace exposes externally accessible libraries from the Runtime APEX.
+# Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.runtime.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.runtime.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.asan.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.links = default
@@ -632,11 +642,11 @@
 # "conscrypt" APEX namespace
 #
 # This namespace is for libraries within the conscrypt APEX.
+# Keep in sync with the "conscrypt" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.conscrypt.isolated = true
 namespace.conscrypt.visible = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.conscrypt.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.asan.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.links = runtime,default
diff --git a/rootdir/etc/ld.config.vndk_lite.txt b/rootdir/etc/ld.config.vndk_lite.txt
index 02b1bfa..4ce7f52 100644
--- a/rootdir/etc/ld.config.vndk_lite.txt
+++ b/rootdir/etc/ld.config.vndk_lite.txt
@@ -43,6 +43,9 @@
 # partitions are also allowed temporarily.
 ###############################################################################
 namespace.default.isolated = false
+# Visible because some libraries are dlopen'ed, e.g. libopenjdk is dlopen'ed by
+# libart.
+namespace.default.visible = true
 
 namespace.default.search.paths  = /system/${LIB}
 namespace.default.search.paths += /odm/${LIB}
@@ -61,8 +64,7 @@
 namespace.default.asan.search.paths += /data/asan/%PRODUCT_SERVICES%/${LIB}
 namespace.default.asan.search.paths +=           /%PRODUCT_SERVICES%/${LIB}
 
-# Keep in sync with the platform namespace in the com.android.runtime APEX
-# ld.config.txt.
+# Keep in sync with the "platform" namespace in art/build/apex/ld.config.txt.
 # If a shared library or an executable requests a shared library that
 # cannot be loaded into the default namespace, the dynamic linker tries
 # to load the shared library from the runtime namespace. And then, if the
@@ -70,9 +72,6 @@
 # dynamic linker tries to load the shared library from the resolv namespace.
 # Finally, if all attempts fail, the dynamic linker returns an error.
 namespace.default.links = runtime,resolv
-# Visible because some libraries are dlopen'ed, e.g. libopenjdk is dlopen'ed by
-# libart.
-namespace.default.visible = true
 namespace.default.link.runtime.shared_libs  = libandroidicu.so
 namespace.default.link.runtime.shared_libs += libdexfile_external.so
 namespace.default.link.runtime.shared_libs += libdexfiled_external.so
@@ -92,12 +91,13 @@
 # "runtime" APEX namespace
 #
 # This namespace pulls in externally accessible libs from the Runtime APEX.
+# Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.runtime.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# Keep in sync with the default namespace in the com.android.runtime APEX
-# ld.config.txt.
 namespace.runtime.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.asan.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.links = default
@@ -130,11 +130,11 @@
 # "conscrypt" APEX namespace
 #
 # This namespace is for libraries within the conscrypt APEX.
+# Keep in sync with the "conscrypt" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.conscrypt.isolated = true
 namespace.conscrypt.visible = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.conscrypt.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.asan.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.links = runtime,default
@@ -177,6 +177,8 @@
 # Note that there is no link from the default namespace to this namespace.
 ###############################################################################
 namespace.sphal.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
 namespace.sphal.visible = true
 
 namespace.sphal.search.paths  = /odm/${LIB}
@@ -266,6 +268,8 @@
 # This namespace is exclusively for vndk-sp libs.
 ###############################################################################
 namespace.vndk.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
 namespace.vndk.visible = true
 
 namespace.vndk.search.paths  = /odm/${LIB}/vndk-sp
@@ -369,10 +373,10 @@
 # "runtime" APEX namespace
 #
 # This namespace exposes externally accessible libraries from the Runtime APEX.
+# Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.runtime.isolated = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.runtime.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.asan.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.links = default
@@ -389,6 +393,10 @@
 [unrestricted]
 additional.namespaces = runtime,media,conscrypt,resolv
 
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
+namespace.default.visible = true
+
 namespace.default.search.paths  = /system/${LIB}
 namespace.default.search.paths += /odm/${LIB}
 namespace.default.search.paths += /vendor/${LIB}
@@ -400,10 +408,8 @@
 namespace.default.asan.search.paths += /data/asan/vendor/${LIB}
 namespace.default.asan.search.paths +=           /vendor/${LIB}
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
+# Keep in sync with the "platform" namespace in art/build/apex/ld.config.txt.
 namespace.default.links = runtime,resolv
-namespace.default.visible = true
-
 namespace.default.link.runtime.shared_libs  = libandroidicu.so
 namespace.default.link.runtime.shared_libs += libdexfile_external.so
 namespace.default.link.runtime.shared_libs += libdexfiled_external.so
@@ -420,11 +426,13 @@
 # "runtime" APEX namespace
 #
 # This namespace exposes externally accessible libraries from the Runtime APEX.
+# Keep in sync with the "runtime" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.runtime.isolated = true
+# Visible to allow links to be created at runtime, e.g. through
+# android_link_namespaces in libnativeloader.
 namespace.runtime.visible = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.runtime.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.asan.search.paths = /apex/com.android.runtime/${LIB}
 namespace.runtime.links = default
@@ -455,11 +463,11 @@
 # "conscrypt" APEX namespace
 #
 # This namespace is for libraries within the conscrypt APEX.
+# Keep in sync with the "conscrypt" namespace in art/build/apex/ld.config.txt.
 ###############################################################################
 namespace.conscrypt.isolated = true
 namespace.conscrypt.visible = true
 
-# Keep in sync with ld.config.txt in the com.android.runtime APEX.
 namespace.conscrypt.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.asan.search.paths = /apex/com.android.conscrypt/${LIB}
 namespace.conscrypt.links = runtime,default