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Commit 6ac67f72 authored by Dongwon Kang's avatar Dongwon Kang
Browse files

Load MediaPlayer2 implementation with a linker namespace. 

MediaPlayer2 calls System.loadLibrary(media2_jni) and
libmedia2_jni loads the MediaPlayer2 native implementation
in libmediaplayer2_jni with an isolated linker namespace.

Test: build & boot & atest MediaPlayer2Test
Bug: 112766913
Change-Id: I07c542da5ccb305f839cda488c9e83b43c98c9e1
parent 8c30fbae

media/jni/Android.bp

+5 −2
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ cc_library_shared { 
}



cc_library_shared {

    name: "libmedia2_jni",

    name: "libmediaplayer2_jni",



    srcs: [

        "android_media_DataSourceCallback.cpp",
@@ -117,7 +117,10 @@ cc_library_shared { 
        "libz",

    ],



    header_libs: ["libhardware_headers"],

    header_libs: [

        "libhardware_headers",

        "libnativewindow_headers",

    ],



    static_libs: [

        "libbase",

media/jni/Android.mk

0 → 100644
+30 −0
Original line number Diff line number Diff line 
LOCAL_PATH := $(call my-dir)



include $(CLEAR_VARS)

LOCAL_CFLAGS := -Wall -Werror

LOCAL_SRC_FILES := \

    Media2Jni.cpp \



# TODO: Move libmedia2_jni from system to media apex. Currently, libraries defined in

#       Android.mk is not visible in apex build.

LOCAL_MODULE:= libmedia2_jni

LOCAL_SHARED_LIBRARIES := libdl liblog



sanitizer_runtime_libraries := $(call normalize-path-list,$(addsuffix .so,\

  $(ADDRESS_SANITIZER_RUNTIME_LIBRARY) \

  $(UBSAN_RUNTIME_LIBRARY) \

  $(TSAN_RUNTIME_LIBRARY)))



# $(info Sanitizer:  $(sanitizer_runtime_libraries))



ndk_libraries := $(call normalize-path-list,$(addprefix lib,$(addsuffix .so,\

  $(NDK_PREBUILT_SHARED_LIBRARIES))))



# $(info NDK:  $(ndk_libraries))



LOCAL_CFLAGS += -DLINKED_LIBRARIES='"$(sanitizer_runtime_libraries):$(ndk_libraries)"'



sanitizer_runtime_libraries :=

ndk_libraries :=



include $(BUILD_SHARED_LIBRARY)

media/jni/Media2Jni.cpp

0 → 100644
+89 −0
Original line number Diff line number Diff line 
/*

**

** Copyright 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.

*/



//#define LOG_NDEBUG 0

#define LOG_TAG "MediaPlayer2-JNI"

#include "utils/Log.h"



#include "jni.h"

#include <android/dlext.h>

#include <dirent.h>

#include <dlfcn.h>

#include <errno.h>

#include <string.h>



extern "C" {

  // Copied from GraphicsEnv.cpp

  // TODO(b/37049319) Get this from a header once one exists

  android_namespace_t* android_create_namespace(const char* name,

                                                const char* ld_library_path,

                                                const char* default_library_path,

                                                uint64_t type,

                                                const char* permitted_when_isolated_path,

                                                android_namespace_t* parent);

  bool android_link_namespaces(android_namespace_t* from,

                               android_namespace_t* to,

                               const char* shared_libs_sonames);

  enum {

     ANDROID_NAMESPACE_TYPE_ISOLATED = 1,

  };



}  // extern "C"



static const char kApexLibPath[] =  "/apex/com.android.media/lib"

#ifdef __LP64__

    "64"

#endif

    "/";

static const char kMediaPlayer2LibPath[] =  "/apex/com.android.media/lib"

#ifdef __LP64__

    "64"

#endif

    "/libmediaplayer2_jni.so";



typedef jint (*Media2JniOnLoad)(JavaVM*, void*);



JNIEXPORT jint JNI_OnLoad(JavaVM* vm, void* reserved)

{

    android_namespace_t *media2Ns = android_create_namespace("media2",

            nullptr,  // ld_library_path

            kApexLibPath,

            ANDROID_NAMESPACE_TYPE_ISOLATED,

            nullptr,  // permitted_when_isolated_path

            nullptr); // parent

    if (!android_link_namespaces(media2Ns, nullptr, LINKED_LIBRARIES)) {

        ALOGE("Failed to link namespace. Failed to load extractor plug-ins in apex.");

        return -1;

    }

    const android_dlextinfo dlextinfo = {

        .flags = ANDROID_DLEXT_USE_NAMESPACE,

        .library_namespace = media2Ns,

    };

    // load libmediaplayer2_jni and call JNI_OnLoad.

    void *libHandle = android_dlopen_ext(kMediaPlayer2LibPath, RTLD_NOW | RTLD_LOCAL, &dlextinfo);

    if (libHandle == NULL) {

        ALOGW("couldn't dlopen(%s) %s", kMediaPlayer2LibPath, strerror(errno));

        return -1;

    }

    Media2JniOnLoad media2JniOnLoad = (Media2JniOnLoad) dlsym(libHandle, "JNI_OnLoad");

    if (!media2JniOnLoad) {

        ALOGW("%s does not contain JNI_OnLoad()", kMediaPlayer2LibPath);

        dlclose(libHandle);

        return -1;

    }

    return media2JniOnLoad(vm, reserved);

}