android 4.2.1 MTK JB2 源码编译跑起来遇到奇葩问题

拿 MTK JB2(android 4.2.1)源码包编译出来的卡刷，然后“设置”中发现内置存储空间和外置 sd 卡可用空间都为 0 ，其他任何应用也反映可用空间 0 。但 adb shell 进去均可正常访问， df 也显示正常。

看了看 /etc/permissions/platform.xml 是正常的， sdcard_rw media_rw 都在。无奈只有简单调试了一下，我在“设置”->"存储"的代码加了log：

    private void measureApproximateStorage(IMediaContainerService imcs) {
        /*final String path = mVolume != null ? mVolume.getPath()
                : Environment.getDataDirectory().getPath();*/
        
        final String path;
        if(mVolume != null) {
            path = mVolume.getPath();
        } else {
            if(FeatureOption.MTK_SHARED_SDCARD) {
                path = Environment.getLegacyExternalStorageDirectory().getPath();
            } else {
                path = Environment.getDataDirectory().getPath();
            }
        }
        Log.d(TAG, "measureApproximateStorage, path is " + path);
        
        try {
            final long[] stats = imcs.getFileSystemStats(path);
            mTotalSize = stats[0];
            mAvailSize = stats[1];
            Log.d(TAG, "total size:" + mTotalSize + " path:" + path);
        } catch (Exception e) {
            Log.w(TAG, "Problem in container service", e);
        }

        sendInternalApproximateUpdate();
    }

结果：

D/StorageMeasurement( 1454): ## total size:2142347264 path:/data

D/StorageMeasurement( 1454): ## total size:0 path:/storage/sdcard1

D/StorageMeasurement( 1454): ## total size:0 path:/storage/sdcard0

再往下追踪直到 native 层： libcore/luni/src/main/native/libcore_io_Posix.cpp ，我也加了 log

static jobject Posix_statfs(JNIEnv* env, jobject, jstring javaPath) {
    ScopedUtfChars path(env, javaPath);
    if (path.c_str() == NULL) {
        return NULL;
    }
    struct statfs sb;

    int rc = TEMP_FAILURE_RETRY(statfs(path.c_str(), &sb));

    ALOGE("[My Debug]##path:%s blocks:%llu rc:%d uid:%d gid:%d", path.c_str(), sb.f_blocks, rc, getuid(), getgid());
    if (rc == -1) {
        throwErrnoException(env, "statfs");
        return NULL;
    }
    return makeStructStatFs(env, sb);
}

结果：

E/Posix ( 1524): [My Debug]## path:/storage/sdcard1 blocks:0 rc:0 uid:10018 gid:10018

E/Posix ( 1524): [My Debug]## path:/storage/sdcard0 blocks:0 rc:0 uid:10018 gid:10018

我觉得很可能还是权限问题，就把 /storage/sdcard1 和 0 都 mount -o fmask=0000,dmask=0000 这样 /storage/sdcard0 和 1 权限就是 777 了，试了一下还是不行。

另外，如果 APP 打开这些存储设备会有 log ：

I/DefContainer-JNI( 1884): error opening: /storage/sdcard0: Permission denied

I/DefContainer-JNI( 1884): error opening: /storage/sdcard1: Permission denied

代码在 frameworks/base/packages/DefaultContainerService/jni/com_android_defcontainer_MeasurementUtils.cpp

static jlong native_measureDirectory(JNIEnv* env, jobject clazz, jstring directory) {
    jlong ret = 0L;

    const char* path = env->GetStringUTFChars(directory, NULL);
    if (path == NULL) {
        return ret;
    }

    int dirfd = open(path, O_DIRECTORY, O_RDONLY);
    if (dirfd < 0) {
        ALOGI("error opening: %s: %s", path, strerror(errno));
    } else {
        ret = calculate_dir_size(dirfd);
        close(dirfd);
    }
    env->ReleaseStringUTFChars(directory, path);
    return ret;
}

看来就是调用底层的系统 API 访问文件没权限，但文件系统都已经 777 了还是不行，现在没有其他思路了，希望大伙帮我出出主意。