[Java]调试笔记 - 问题报错Cannot run program “sh“: error=24, Too many open files

问题：

Android采用RootCmd工具类执行adb命令，执行多次之后报错，导致adb命令无法正常执行，先上报错日志；

2020-11-04 21:10:30.307 5843-5843/com.orange.openclose W/System.err: java.io.IOException: Cannot run program "sh": error=24, Too many open files
2020-11-04 21:10:30.308 5843-5843/com.orange.openclose W/System.err:     at java.lang.ProcessBuilder.start(ProcessBuilder.java:983)
2020-11-04 21:10:30.309 5843-5843/com.orange.openclose W/System.err:     at java.lang.Runtime.exec(Runtime.java:691)
2020-11-04 21:10:30.309 5843-5843/com.orange.openclose W/System.err:     at java.lang.Runtime.exec(Runtime.java:524)
2020-11-04 21:10:30.310 5843-5843/com.orange.openclose W/System.err:     at java.lang.Runtime.exec(Runtime.java:421)
2020-11-04 21:10:30.311 5843-5843/com.orange.openclose W/System.err:     at com.orange.openclose.MainActivity.execRootCommand(MainActivity.java:51)
2020-11-04 21:10:30.311 5843-5843/com.orange.openclose W/System.err:     at com.orange.openclose.MainActivity.onCreate(MainActivity.java:24)
2020-11-04 21:10:30.312 5843-5843/com.orange.openclose W/System.err:     at android.app.Activity.performCreate(Activity.java:6709)
2020-11-04 21:10:30.312 5843-5843/com.orange.openclose W/System.err:     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
2020-11-04 21:10:30.313 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2624)
2020-11-04 21:10:30.313 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2732)
2020-11-04 21:10:30.314 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread.-wrap12(ActivityThread.java)
2020-11-04 21:10:30.315 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1483)
2020-11-04 21:10:30.315 5843-5843/com.orange.openclose W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
2020-11-04 21:10:30.316 5843-5843/com.orange.openclose W/System.err:     at android.os.Looper.loop(Looper.java:154)
2020-11-04 21:10:30.316 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:6141)
2020-11-04 21:10:30.317 5843-5843/com.orange.openclose W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
2020-11-04 21:10:30.318 5843-5843/com.orange.openclose W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:912)
2020-11-04 21:10:30.318 5843-5843/com.orange.openclose W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:802)
2020-11-04 21:10:30.320 5843-5843/com.orange.openclose W/System.err: Caused by: java.io.IOException: error=24, Too many open files
2020-11-04 21:10:30.321 5843-5843/com.orange.openclose W/System.err:     at java.lang.UNIXProcess.forkAndExec(Native Method)
2020-11-04 21:10:30.321 5843-5843/com.orange.openclose W/System.err:     at java.lang.UNIXProcess.<init>(UNIXProcess.java:133)
2020-11-04 21:10:30.322 5843-5843/com.orange.openclose W/System.err:     at java.lang.ProcessImpl.start(ProcessImpl.java:128)
2020-11-04 21:10:30.322 5843-5843/com.orange.openclose W/System.err:     at java.lang.ProcessBuilder.start(ProcessBuilder.java:964)
2020-11-04 21:10:30.322 5843-5843/com.orange.openclose W/System.err: 	... 17 more
2020-11-04 21:10:32.330 5843-5843/com.orange.openclose W/System.err: java.io.IOException: Cannot run program "sh": error=24, Too many open files
2020-11-04 21:10:32.331 5843-5843/com.orange.openclose W/System.err:     at java.lang.ProcessBuilder.start(ProcessBuilder.java:983)
2020-11-04 21:10:32.332 5843-5843/com.orange.openclose W/System.err:     at java.lang.Runtime.exec(Runtime.java:691)
2020-11-04 21:10:32.332 5843-5843/com.orange.openclose W/System.err:     at java.lang.Runtime.exec(Runtime.java:524)
2020-11-04 21:10:32.333 5843-5843/com.orange.openclose W/System.err:     at java.lang.Runtime.exec(Runtime.java:421)
2020-11-04 21:10:32.333 5843-5843/com.orange.openclose W/System.err:     at com.orange.openclose.MainActivity.execRootCommand(MainActivity.java:51)
2020-11-04 21:10:32.334 5843-5843/com.orange.openclose W/System.err:     at com.orange.openclose.MainActivity.onCreate(MainActivity.java:35)
2020-11-04 21:10:32.334 5843-5843/com.orange.openclose W/System.err:     at android.app.Activity.performCreate(Activity.java:6709)
2020-11-04 21:10:32.335 5843-5843/com.orange.openclose W/System.err:     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
2020-11-04 21:10:32.336 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2624)
2020-11-04 21:10:32.336 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2732)
2020-11-04 21:10:32.337 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread.-wrap12(ActivityThread.java)
2020-11-04 21:10:32.338 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1483)
2020-11-04 21:10:32.338 5843-5843/com.orange.openclose W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
2020-11-04 21:10:32.339 5843-5843/com.orange.openclose W/System.err:     at android.os.Looper.loop(Looper.java:154)
2020-11-04 21:10:32.339 5843-5843/com.orange.openclose W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:6141)
2020-11-04 21:10:32.340 5843-5843/com.orange.openclose W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
2020-11-04 21:10:32.341 5843-5843/com.orange.openclose W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:912)
2020-11-04 21:10:32.341 5843-5843/com.orange.openclose W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:802)
2020-11-04 21:10:32.343 5843-5843/com.orange.openclose W/System.err: Caused by: java.io.IOException: error=24, Too many open files
2020-11-04 21:10:32.344 5843-5843/com.orange.openclose W/System.err:     at java.lang.UNIXProcess.forkAndExec(Native Method)
2020-11-04 21:10:32.344 5843-5843/com.orange.openclose W/System.err:     at java.lang.UNIXProcess.<init>(UNIXProcess.java:133)
2020-11-04 21:10:32.345 5843-5843/com.orange.openclose W/System.err:     at java.lang.ProcessImpl.start(ProcessImpl.java:128)
2020-11-04 21:10:32.345 5843-5843/com.orange.openclose W/System.err:     at java.lang.ProcessBuilder.start(ProcessBuilder.java:964)
2020-11-04 21:10:32.345 5843-5843/com.orange.openclose W/System.err: 	... 17 more

源码方法：

private Process execRootCommand(String command) throws IOException {if (command == null) {Log.w("command is null");return null;}Runtime runtime = Runtime.getRuntime();//Process proc = runtime.exec("su");Process proc = runtime.exec("sh");OutputStream os = proc.getOutputStream();String cmd = command + "\n";Log.d("cmd  == " + cmd);os.write(cmd.getBytes());os.flush();return proc;
}

百度查阅了下，进程一直开启没有释放，百度查考process.destroy()或者waitfor()可以解决；

直接用了大神的工具类，写了个demo进行循环测试，问题解决。

private  static int execRootCommand(String cmd) {int result = -1;DataOutputStream dos = null;try {Process p = Runtime.getRuntime().exec("sh");dos = new DataOutputStream(p.getOutputStream());//Log.i(TAG, cmd);dos.writeBytes(cmd + "\n");dos.flush();dos.writeBytes("exit\n");dos.flush();p.waitFor();result = p.exitValue();} catch (Exception e) {e.printStackTrace();} finally {if (dos != null) {try {dos.close();} catch (IOException e) {e.printStackTrace();}}}return result;
}

DEMO源码：

public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);new updateScreenTimeThread().start();}
}
class updateScreenTimeThread extends Thread{public static final String TAG = "TestLog";public static  int i = 1;private  static int execRootCommand(String cmd) {int result = -1;DataOutputStream dos = null;try {Process p = Runtime.getRuntime().exec("sh");dos = new DataOutputStream(p.getOutputStream());//Log.i(TAG, cmd);dos.writeBytes(cmd + "\n");dos.flush();dos.writeBytes("exit\n");dos.flush();p.waitFor();result = p.exitValue();} catch (Exception e) {e.printStackTrace();} finally {if (dos != null) {try {dos.close();} catch (IOException e) {e.printStackTrace();}}}return result;}@Overridepublic void run() {while(true){Log.e(TAG,"iiiiiiiiiii = " + i++);execRootCommand("echo 1 > /sys/devices/platform/backlight/backlight/backlight/bl_power");Log.e(TAG,"closesrceen");try {Thread.sleep(3000);} catch (Exception e) {e.printStackTrace();}execRootCommand("echo 0 > /sys/devices/platform/backlight/backlight/backlight/bl_power");Log.e(TAG,"opensrceen");try {Thread.sleep(3000);} catch (Exception e) {e.printStackTrace();}}}
}

调试方法：

网友文档：android代码执行adb shell终端命令（linux命令）并返回执行结果