I have seen someone complain about that Logcat only output the last line. I would like to ask a reserve question that how can I produce this condition which only output the last line?
This is how I read the log by start a thread.
public class ReadLog implements Runnable{
private boolean running = true;
public void stop(){
running = false;
}
#Override
public void run() {
Process proc = null;
try {
//Runtime.getRuntime().exec("/system/bin/logcat -c");
proc = Runtime.getRuntime().exec("/system/bin/logcat ");
}catch(IOException e) {
e.printStackTrace();
}
if(proc != null){
BufferedReader reader = new BufferedReader(new InputStreamReader(proc.getInputStream()));
String line= null;
try {
while((line=reader.readLine())!=null && running){
if(line.contains("specific word")){
doSomething();//do something base on log
running = false;
}
}
}
catch (IOException e) {
e.printStackTrace();
}
finally{
proc.destroy();
}
}
}
}
I want to read the newest line only. The problem is that it would trigger the doSomething() even though the "specific word" is not on last line unless I add Runtime.getRuntime().exec("/system/bin/logcat -c"); the line to clear the log before start running.
It is true that I can add one more while((line=reader.readLine())!=null && running){} to let the BufferedReader go to last line before start running but it may take long time and too late.
I have tried Runtime.getRuntime().exec("/system/bin/logcat | tail -n 1");
But no luck that tail does not accept stdin.
I am asking for any command that output last line of stdout quickly just like tail -n 1 FILE.
try Runtime.getRuntime().exec("/system/bin/logcat -d | tail -n 1");
According to logcat documentation -> -d : "Dumps the log to the screen and exits."
Then readline will return the last new line. (I did not test it).
EDIT :
In fact | tail -n 1 has no effect with "exec", but with "-d" you can get the last log line easily.
try {
//Executes the command.
Process process = Runtime.getRuntime().exec(
"/system/bin/logcat -d");
BufferedReader reader = new BufferedReader(
new InputStreamReader(process
.getInputStream()));
String output;
String lastLine = null;
while ((output = reader.readLine()) != null) {
lastLine = output;
}
reader.close();
//Waits for the command to finish.
process.waitFor();
if(lastLine != null)
System.out.println("Last log line : " + lastLine);
} catch (IOException e) {
throw new RuntimeException(e);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
Don't forget to add READ_LOGS permission to your manifest :
<uses-permission android:name="android.permission.READ_LOGS" />
Related
I am trying to execute 'top' command with following code which is working correctly:
try {
Process proc = Runtime.getRuntime().exec("top");
InputStream is = proc.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is), 500);
StringBuilder output = new StringBuilder();
String line = "";
int count = 0;
while ((line = reader.readLine()) != null) {
if(line.trim().equals(""))
continue;
if (line.trim().startsWith("User")) {
count++;
if (count > 2)
break; //'top' command keeps repeating call to itself. we need to stop after 1 call
}
if (line.contains("PID")) {
mainInfo.append(output.toString());
output.delete(0,output.length());
continue;
}
output.append(line)
.append(CPUInfoUtil.SEPARATOR_LINE); //append this separator to help parsing
}
reader.close();
proc.destroy();
return output.toString();
} catch (FileNotFoundException e) {
return null;
} catch (IOException e) {
throw new RuntimeException(e);
}
This is returning me all processes including kernel/root processes. I want to get only system processes except woner=root. For that I tried following 'top' with following options, which didn't work:
Process proc = Runtime.getRuntime().exec(new String[]{"top","U","!root"});
I know I can also get running processes using following code but it does not provide additional information that 'top' provides (e.g. Cpu%, thread count etc):
((ActivityManager) act.getSystemService(Context.ACTIVITY_SERVICE)).getRunningServices(Integer.MAX_VALUE);
After doing a lot of homework I got this working! Following way 'top' can be used with as many options:
String[] cmd = {"sh","-c",
"top -m 100 -n 1"
};
Process proc = Runtime.getRuntime().exec(cmd);
I have use -m and -n options and its working great. See manual for whole list of options:
'top' options
I am using
Process psProc = Runtime.getRuntime().exec("top -n 1 -d 5");
to get all the process running and then calculate CPU usage for android apps.
I have an Activity which every second write a counter to the logcat:
Runnable rLog = new Runnable() {
#Override
public void run() {
i++;
Log.d("bbb", "i= " + i);
handler.postDelayed(this, 1000);
}
};
In addition - I have a service which read from "logcat -s bbb" and log it:
Runnable rGetLog = new Runnable() {
#Override
public void run() {
Runtime rt = Runtime.getRuntime();
Process process = null;
try {
process = rt.exec("logcat -s bbb");
} catch (IOException e1) {
e1.printStackTrace();
}
BufferedReader bufferedReader =
new BufferedReader(new InputStreamReader(process.getInputStream()));
try {
while ((line = bufferedReader.readLine()) != null)
{
Log.d("aaa", "get line = " + line);
}
} catch (IOException e) {
e.printStackTrace();
}
}
};
This code works well. The problem starts when I change the tag "bbb" to a real tag such as "AndroidRuntime" or another tag... I got an empty response from logcat
(if I run at the same time "logcat -s AndroidRuntime" from adb I got lots of lines...)
Who knows what the problem is? what can be different?
Thanks!
From Android Jelly Bean, applications cannot read log entries from other applications, unless your device is rooted and you read the logs as superuser.
try using sudo to get permissions:
process = rt.exec("su && logcat -s YOUR_TAG");
On a rooted android device, I tried to run a cat command that read kernel log, as follow:
Process p = Runtime.getRuntime().exec("su");
p = Runtime.getRuntime().exec("/system/bin/cat /proc/kmsg");
The su command was successfully executed but not the cat.
I tried to read the output of the command using getInputStream() but nothing was there, as follow:
BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((read = err.read(buffer)) > 0)
{ //read error to buffer
catOutput.append(buffer, 0, read);
}
in.close();
I used the same code with ls command instead of displaying the kernel log, it worked just fine and show me the result.
I wonder if what error I am getting and wantted to see the error message on the shell when executing the cat command. Tried the p.getErrorStream() but it doesn't give me any result.
Could any one help me with this ? Thanks.
Here's a comprehensive example on how to do this - note that I got the idea from this answer:
public void catKmsg() {
Runtime runtime = Runtime.getRuntime();
Process proc = null;
OutputStreamWriter osw = null;
StringBuilder sbstdOut = new StringBuilder();
StringBuilder sbstdErr = new StringBuilder();
String command="/system/bin/cat /proc/kmsg";
try { // Run Script
proc = runtime.exec("su");
osw = new OutputStreamWriter(proc.getOutputStream());
osw.write(command);
osw.flush();
osw.close();
} catch (IOException ex) {
ex.printStackTrace();
} finally {
if (osw != null) {
try {
osw.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
try {
if (proc != null) {
proc.waitFor();
}
} catch (InterruptedException e) {
e.printStackTrace();
}
sbstdOut.append(ReadBufferedReader(new InputStreamReader
(proc.getInputStream())));
sbstdErr.append(ReadBufferedReader(new InputStreamReader
(proc.getErrorStream())));
if (proc.exitValue() != 0) {
}
}
I finally found the solution for the problem by using RootTools library.
Recently released (few months after my question was asked), RootTools provides a easy-to-use tool set that helps running commands that required root privilege. I created a wrapper to check if root access is available before executing shell command:
void testRootToolsCommand(String command){
if (RootTools.isRootAvailable())
toastMessage("Root is available !!!");
else {
toastMessage("NO ROOT !!! ");
return;
}
int timeOut = 1000;
try {
List<String> output = RootTools.sendShell(command,timeOut);
toastMessage("OUTPUT of the command \n" + output.toString());
} catch (RootToolsException re) {
toastMessage("Funny thing happened with RootTools!!! ");
} catch (TimeoutException te)
{
toastMessage("Timeout exception - Increase timeout !!! !!! ");
}
catch (Exception e) {
toastMessage(e.getMessage().toString());
}
}
An example of a function call is:
testRootToolsCommand("cat /proc/kmsg > /sdcard/jun11_4h51.txt");
Note: The Tool also support running multiple commands at once.
I read the other posts and can't figure out the "trick".
I looked at Log Collector but can't use a separate APK. I'm basically using the same approach and I consistently get nothing back on the processes inputstream.
I have READ_LOGS in the manifest.
From within my default activity, I'm able to get the log, but if I move the logic to another activity or utilize an asynctask, no output is returned.
this code is from my default activity... inline, i dump it to the log
try {
Process process = Runtime.getRuntime().exec("logcat -d");
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(process.getInputStream()));
StringBuilder log=new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
log.append(line);
}
Log.d(LOGTAG, "Logcat: " +log.toString());
} catch (IOException e) {}
if i wrap it in an asynctask or just inline it in another activity, it returns nothing
ArrayList<String> commandLine = new ArrayList<String>();
//terminate on completion and suppress everything except the filter
commandLine.add("logcat -d -s");
...
//replace asynctask with inline (could not get log in asynctask)
showProgressDialog(getString(R.string.acquiring_log_progress_dialog_message));
final StringBuilder log = new StringBuilder();
BufferedReader bufferedReader = null;
try{
Process process = Runtime.getRuntime().exec(commandLine.toArray(new String[0]));
bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line;
while ((line = bufferedReader.readLine()) != null){
log.append(line);
log.append(MangoApp.LINE_SEPARATOR);
}
sendIntent.putExtra(Intent.EXTRA_TEXT, log.toString());
startActivity(Intent.createChooser(sendIntent, getString(R.string.chooser_title)));
dismissProgressDialog();
dismissMainDialog();
finish();
}
catch (IOException e){
dismissProgressDialog();
showErrorDialog(getString(R.string.failed_to_get_log_message));
Log.e(LOGTAG, "Log collection failed: ", e);//$NON-NLS-1$
} finally {
if (bufferedReader != null) {
try {
bufferedReader.close();
} catch (IOException ignore) {}
}
}
Can anyone spot the diff or explain the magic? I'm pretty sure the commandline is right in the second version so scratching my head. I'm using 2.1 SDK 7 on the emulator.
Thanks
Hope this will be helpful, you don't have to create file by your self just execute the below command, to get the error info.
Runtime.getRuntime().exec("logcat -v time -r 100 -f /sdcard/log.txt *:E");
Logcat parameters options:
-r <size in kilobytes> -> for specifying the size of file
-f <filename> -> file to which you want to write the logs.
Can you try it without the ArrayList. Just pass the command String
I have implemented it in the following way (without the ArrayList). It works for me.
String baseCommand = "logcat -v time";
baseCommand += " MyApp:I "; // Info for my app
baseCommand += " *:S "; // Silence others
ServicesController.logReaderProcess = Runtime.getRuntime().exec(baseCommand);
Please Tell me it is possible to run a shell script file from My Android application.
and read the data from script file.
If it is possible than how to proceed , Please give me some guideline.
You can use this code snippet (from Aaron C)
void execCommandLine(String command)
{
Runtime runtime = Runtime.getRuntime();
Process proc = null;
OutputStreamWriter osw = null;
try
{
proc = runtime.exec("su");
osw = new OutputStreamWriter(proc.getOutputStream());
osw.write(command);
osw.flush();
osw.close();
}
catch (IOException ex)
{
Log.e("execCommandLine()", "Command resulted in an IO Exception: " + command);
return;
}
finally
{
if (osw != null)
{
try
{
osw.close();
}
catch (IOException e){}
}
}
try
{
proc.waitFor();
}
catch (InterruptedException e){}
if (proc.exitValue() != 0)
{
Log.e("execCommandLine()", "Command returned error: " + command + "\n Exit code: " + proc.exitValue());
}
}
But this requires root access I think.
You could also try to use GScript
I've been using this to run shell scripts in my android app. Only thing I've yet to figure out how to do is direct the output to where I want it. You don't need root for this, which is why I'm posting.
Process process = Runtime.getRuntime().exec("top -n 1");
//Get the output of top so that it can be read
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));