从Linux/Android上的另一个共享库检查加载的共享库

Question

是否可以检查调用进程从另一个共享库（.so）加载的共享库？我知道那里有命令行工具，但是可以在C++代码中执行这样的检查吗？

我需要以某种方式获取由Android应用程序加载的本机共享库列表，但它似乎不可能从Java代码。

Answer 1

对于调用进程，您可以使用/proc/<pid>/maps文件或只使用/proc/self/maps：以'.so'结尾的行用于链接的共享库。这是一个黑客，但应该工作。请注意，一个库可能被映射多次，因此您需要跳过重复。

好消息：你可以从java中完成。下面的代码片段将当前进程的共享库打印到logcat。

try { 
    Set<String> libs = new HashSet<String>(); 
    String mapsFile = "/proc/self/maps"; 
    BufferedReader reader = new BufferedReader(new FileReader(mapsFile)); 
    String line; 
    while ((line = reader.readLine()) != null) { 
     if (line.endsWith(".so")) { 
      int n = line.lastIndexOf(" "); 
      libs.add(line.substring(n + 1)); 
     } 
    } 
    Log.d("Ldd", libs.size() + " libraries:"); 
    for (String lib : libs) { 
     Log.d("Ldd", lib); 
    } 
} catch (FileNotFoundException e) { 
    // Do some error handling... 
} catch (IOException e) { 
    // Do some error handling... 
} 

设备上的输出是：

D/Ldd  (11286): 55 libraries: 
D/Ldd  (11286): /system/lib/libc.so 
D/Ldd  (11286): /system/lib/libdbus.so 
D/Ldd  (11286): /system/lib/librpc.so 
D/Ldd  (11286): /system/lib/libEGL.so 
D/Ldd  (11286): /system/lib/libstagefright_color_conversion.so 
D/Ldd  (11286): /system/lib/libmedia.so 
D/Ldd  (11286): /system/lib/libemoji.so 
D/Ldd  (11286): /system/lib/libcrypto.so 
D/Ldd  (11286): /system/lib/libstagefright_avc_common.so 
D/Ldd  (11286): /system/lib/libnativehelper.so 
D/Ldd  (11286): /system/lib/libskiagl.so 
D/Ldd  (11286): /system/lib/libopencore_player.so 
D/Ldd  (11286): /system/lib/libjpeg.so 
D/Ldd  (11286): /system/lib/libsurfaceflinger_client.so 
D/Ldd  (11286): /system/lib/libstagefright.so 
D/Ldd  (11286): /system/lib/libdrm1.so 
D/Ldd  (11286): /system/lib/libdvm.so 
D/Ldd  (11286): /system/lib/libwebcore.so 
D/Ldd  (11286): /system/lib/libGLESv1_CM.so 
D/Ldd  (11286): /system/lib/libhardware.so 
D/Ldd  (11286): /system/lib/libexif.so 
D/Ldd  (11286): /system/lib/libgps.so 
D/Ldd  (11286): /system/lib/liblog.so 
D/Ldd  (11286): /system/lib/libexpat.so 
D/Ldd  (11286): /system/lib/libopencore_common.so 
D/Ldd  (11286): /system/lib/libbluedroid.so 
D/Ldd  (11286): /system/lib/libm.so 
D/Ldd  (11286): /system/lib/libicui18n.so 
D/Ldd  (11286): /system/lib/libomx_amrenc_sharedlibrary.so 
D/Ldd  (11286): /system/lib/libwpa_client.so 
D/Ldd  (11286): /system/lib/libstdc++.so 
D/Ldd  (11286): /system/lib/libandroid_runtime.so 
D/Ldd  (11286): /system/lib/libz.so 
D/Ldd  (11286): /system/lib/libETC1.so 
D/Ldd  (11286): /system/lib/libsonivox.so 
D/Ldd  (11286): /system/lib/libstlport.so 
D/Ldd  (11286): /system/lib/libutils.so 
D/Ldd  (11286): /system/lib/libicudata.so 
D/Ldd  (11286): /system/lib/libsqlite.so 
D/Ldd  (11286): /system/lib/libhardware_legacy.so 
D/Ldd  (11286): /system/lib/libpixelflinger.so 
D/Ldd  (11286): /system/lib/libvorbisidec.so 
D/Ldd  (11286): /system/lib/libstagefright_amrnb_common.so 
D/Ldd  (11286): /system/lib/libcutils.so 
D/Ldd  (11286): /system/lib/libui.so 
D/Ldd  (11286): /system/lib/libmedia_jni.so 
D/Ldd  (11286): /system/lib/libomx_sharedlibrary.so 
D/Ldd  (11286): /system/lib/libcamera_client.so 
D/Ldd  (11286): /system/lib/libskia.so 
D/Ldd  (11286): /system/lib/libopencore_net_support.so 
D/Ldd  (11286): /system/lib/libnetutils.so 
D/Ldd  (11286): /system/lib/libbinder.so 
D/Ldd  (11286): /system/lib/libssl.so 
D/Ldd  (11286): /system/lib/libicuuc.so 
D/Ldd  (11286): /system/lib/libGLESv2.so 

此外，如果必要PID可以通过android.os.Process.myPid()来获得。

Answer 2

WRT java，启动一个进程，在有问题的.so上调用ldd。捕获来自标准输出的输出，并处理输出：

Process process = Runtime.getRuntime().exec("ldd a.so"); 
StreamGobbler outputGobbler = new StreamGobbler(process.getInputStream()); 
outputGobbler.start(); 
process.waitFor(); 
String result = outputGobbler.buffer; 

参考开创性的岗位上StreamGobbler一类定义。我添加了一个String buffer变量，并将此行0123FF替换为上一个链接的类定义中的buffer = buffer + line+"\n";。显然，我也将第二个参数丢给了构造函数。

class StreamGobbler extends Thread 
{ 
    InputStream is; 
    String buffer; 

    StreamGobbler(InputStream is) 
    { 
     this.is = is; 
     this.buffer = ""; 
    } 

    public void run() 
    { 
     try 
     { 
      InputStreamReader isr = new InputStreamReader(is); 
      BufferedReader br = new BufferedReader(isr); 
      String line=null; 
      while ((line = br.readLine()) != null) 
       buffer += line+"\n";  
      } catch (IOException ioe) 
       { 
       ioe.printStackTrace(); 
       } 
    } 
}