c++ - 无法在 Android Marshmallow 上加载 native 库，但可以在 Lollipop 上运行？

Question

我的应用程序使用 native 库 (libfoo.so)，并且在 Lollipop 上运行良好。但由于 致命信号 11 (SIGSEGV)，代码 1，，它无法在 Marshmallow 上加载库。这是什么原因？

我知道 M 带来了新的权限模型，但它似乎与此无关，因为库只是加载而没有做任何事情。

日志:

11-20 12:38:53.390  14997-15010/name.antonsmirnov.android.libfoo D/libfooIssueProject﹕ Start loading libraries
11-20 12:38:53.394  14997-15010/name.antonsmirnov.android.libfoo D/libfooIssueProject﹕ loading/data/user/0/name.antonsmirnov.android.libfoo/cache/sdk/libc.so, file exists=true
11-20 12:38:53.396  14997-15010/name.antonsmirnov.android.libfoo D/libfooIssueProject﹕ loading/data/user/0/name.antonsmirnov.android.libfoo/cache/sdk/libdl.so, file exists=true
11-20 12:38:53.397  14997-15010/name.antonsmirnov.android.libfoo D/libfooIssueProject﹕ loading/data/user/0/name.antonsmirnov.android.libfoo/cache/sdk/libm.so, file exists=true
11-20 12:38:53.398  14997-15010/name.antonsmirnov.android.libfoo D/libfooIssueProject﹕ loading/data/user/0/name.antonsmirnov.android.libfoo/cache/sdk/libstdc++.so, file exists=true
11-20 12:38:53.400  14997-15010/name.antonsmirnov.android.libfoo D/libfooIssueProject﹕ loading/data/user/0/name.antonsmirnov.android.libfoo/cache/sdk/libgnustl_shared.so, file exists=true
11-20 12:38:53.402  14997-15010/name.antonsmirnov.android.libfoo D/libfooIssueProject﹕ loading/data/user/0/name.antonsmirnov.android.libfoo/cache/sdk/libfoo.so, file exists=true
11-20 12:38:53.403  14997-15010/name.antonsmirnov.android.libfoo W/linker﹕ /data/data/name.antonsmirnov.android.libfoo/cache/sdk/libfoo.so: unused DT entry: type 0x1d arg 0x35ac
11-20 12:38:53.410  14997-15010/name.antonsmirnov.android.libfoo A/libc﹕ Fatal signal 11 (SIGSEGV), code 1, fault addr 0xd0 in tid 15010 (Thread-187)
11-20 12:38:53.976      243-243/? W/debuggerd﹕ type=1400 audit(0.0:68): avc: denied { search } for name="name.antonsmirnov.android.libfoo" dev="dm-2" ino=81264 scontext=u:r:debuggerd:s0 tcontext=u:object_r:app_data_file:s0:c512,c768 tclass=dir permissive=0
11-20 12:38:53.980      243-243/? A/DEBUG﹕ *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
11-20 12:38:53.980      243-243/? A/DEBUG﹕ Build fingerprint: 'google/volantisg/flounder_lte:6.0/MRA58N/2289998:user/release-keys'
11-20 12:38:53.980      243-243/? A/DEBUG﹕ Revision: '0'
11-20 12:38:53.980      243-243/? A/DEBUG﹕ ABI: 'arm'
11-20 12:38:53.980      243-243/? A/DEBUG﹕ pid: 14997, tid: 15010, name: Thread-187  >>> name.antonsmirnov.android.libfoo <<<
11-20 12:38:53.980      243-243/? A/DEBUG﹕ signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0xd0
11-20 12:38:53.996      243-243/? A/DEBUG﹕ r0 00000138  r1 000000dc  r2 000000f8  r3 e1fafa84
11-20 12:38:53.996      243-243/? A/DEBUG﹕ r4 000000bc  r5 00000000  r6 00000108  r7 000000ec
11-20 12:38:53.996      243-243/? A/DEBUG﹕ r8 f73186ec  r9 0000006d  sl f0c124e4  fp f73113f6
11-20 12:38:53.996      243-243/? A/DEBUG﹕ ip 00000010  sp f3fd6280  lr 00000008  pc e020d280  cpsr 20070010
11-20 12:38:53.997      243-243/? A/DEBUG﹕ backtrace:
11-20 12:38:53.997      243-243/? A/DEBUG﹕ #00 pc 01294280  /data/data/name.antonsmirnov.android.libfoo/cache/sdk/libfoo.so
11-20 12:38:53.997      243-243/? A/DEBUG﹕ #01 pc 00000004  <unknown>
11-20 12:38:53.976      243-243/? W/debuggerd﹕ type=1400 audit(0.0:69): avc: denied { search } for name="name.antonsmirnov.android.libfoo" dev="dm-2" ino=81264 scontext=u:r:debuggerd:s0 tcontext=u:object_r:app_data_file:s0:c512,c768 tclass=dir permissive=0
11-20 12:38:53.976      243-243/? W/debuggerd﹕ type=1400 audit(0.0:70): avc: denied { search } for name="name.antonsmirnov.android.libfoo" dev="dm-2" ino=81264 scontext=u:r:debuggerd:s0 tcontext=u:object_r:app_data_file:s0:c512,c768 tclass=dir permissive=0
11-20 12:38:53.976      243-243/? W/debuggerd﹕ type=1400 audit(0.0:71): avc: denied { search } for name="name.antonsmirnov.android.libfoo" dev="dm-2" ino=81264 scontext=u:r:debuggerd:s0 tcontext=u:object_r:app_data_file:s0:c512,c768 tclass=dir permissive=0
11-20 12:38:53.976      243-243/? W/debuggerd﹕ type=1400 audit(0.0:72): avc: denied { search } for name="name.antonsmirnov.android.libfoo" dev="dm-2" ino=81264 scontext=u:r:debuggerd:s0 tcontext=u:object_r:app_data_file:s0:c512,c768 tclass=dir permissive=0
11-20 12:38:53.976      243-243/? W/debuggerd﹕ type=1400 audit(0.0:73): avc: denied { search } for name="name.antonsmirnov.android.libfoo" dev="dm-2" ino=81264 scontext=u:r:debuggerd:s0 tcontext=u:object_r:app_data_file:s0:c512,c768 tclass=dir permissive=0
11-20 12:38:53.986      243-243/? W/debuggerd﹕ type=1400 audit(0.0:74): avc: denied { search } for name="name.antonsmirnov.android.libfoo" dev="dm-2" ino=81264 scontext=u:r:debuggerd:s0 tcontext=u:object_r:app_data_file:s0:c512,c768 tclass=dir permissive=0
11-20 12:38:54.383      243-243/? A/DEBUG﹕ Tombstone written to: /data/tombstones/tombstone_05
11-20 12:38:54.383      243-243/? E/DEBUG﹕ AM write failed: Broken pipe
11-20 12:38:54.409      680-696/? I/BootReceiver﹕ Copying /data/tombstones/tombstone_05 to DropBox (SYSTEM_TOMBSTONE)
11-20 12:38:54.422    680-15045/? W/ActivityManager﹕ Force finishing activity name.antonsmirnov.android.libfoo/.MainActivity
11-20 12:38:54.424      680-698/? E/JavaBinder﹕ !!! FAILED BINDER TRANSACTION !!!  (parcel size = 60)
11-20 12:38:54.430      680-752/? W/InputDispatcher﹕ channel 'adb9cab name.antonsmirnov.android.libfoo/name.antonsmirnov.android.libfoo.MainActivity (server)' ~ Consumer closed input channel or an error occurred.  events=0x9
11-20 12:38:54.430     680-6202/? D/GraphicsStats﹕ Buffer count: 7
11-20 12:38:54.439      680-752/? E/InputDispatcher﹕ channel 'adb9cab name.antonsmirnov.android.libfoo/name.antonsmirnov.android.libfoo.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
11-20 12:38:54.447      680-752/? W/InputDispatcher﹕ channel '7b55887 Toast (server)' ~ Consumer closed input channel or an error occurred.  events=0x9
11-20 12:38:54.447      680-752/? E/InputDispatcher﹕ channel '7b55887 Toast (server)' ~ Channel is unrecoverably broken and will be disposed!
11-20 12:38:54.449      252-252/? I/Zygote﹕ Process 14997 exited due to signal (11)
11-20 12:38:54.542      680-857/? I/WindowState﹕ WIN DEATH: Window{7b55887 u0 Toast}
11-20 12:38:54.542      680-857/? W/InputDispatcher﹕ Attempted to unregister already unregistered input channel '7b55887 Toast (server)'
11-20 12:38:54.553     680-1361/? I/WindowState﹕ WIN DEATH: Window{adb9cab u0 name.antonsmirnov.android.libfoo/name.antonsmirnov.android.libfoo.MainActivity}

代码:

private void loadLibrary(File PATH, String libName) {
    File libFile = new File(PATH, "lib" + libName + ".so");
    String libPath = libFile.getAbsolutePath();
    Log.d(TAG, "loading" + libPath + ", file exists=" + libFile.exists());

    System.load(libPath);
}

private void loadLibs() {
    showMessage("Start loading libraries");

    // don't change load order!
    try {
        loadLibrary(sdkFolder, "c");
        loadLibrary(sdkFolder, "dl");
        loadLibrary(sdkFolder, "m");
        loadLibrary(sdkFolder, "stdc++");
        loadLibrary(sdkFolder, "gnustl_shared");
//        loadLibrary(sdkFolder, "z");

        loadLibrary(sdkFolder, "foo"); // crashes here

        showMessage("Libraries loaded !");
    } catch (Throwable t) {
        t.printStackTrace();
        showMessage("Error loading library: " + t.getMessage());
    }
}

附言。该库是使用最新的 android NDK 10e 编译的，该应用程序至少使用同一个库运行了两年。

PPS。我使用 ndk 中的 readelf 分析了文本重定位，但没有发现任何重定位。另外，我没有关于 Lollipop 搬迁的警告，所以我认为这是另一个问题。

Answer 1

Google 已经改变了 Marshmallow 及以上版本私有(private)库的使用；这可能就是您遇到的情况。

从 Android 7.0 开始，系统会阻止应用动态链接非 NDK 库，这可能会导致您的应用崩溃。

根据此表:https://developer.android.com/about/versions/nougat/android-7.0-changes.html#ndk .当您使用私有(private)库运行 Lollipop 时，您应该能够看到 logcat 警告。例如:

03-21 17:07:51.502 31234 31234 W linker  : library "libandroid_runtime.so"
("/system/lib/libandroid_runtime.so") needed or dlopened by
"/data/app/com.popular-app.android-2/lib/arm/libapplib.so" is not accessible
for the namespace "classloader-namespace" - the access is temporarily granted
as a workaround for http://b/26394120