In java, after getting root permissions, how can I open files with it? Can I open them with File class or do I have to use a command?
You will have to use the su command.
I suggest you have a look at how to use su
Sample code to read a file ( I haven't tested it but it should give you an idea ):
public static void runAsRoot(String[] cmds){
try {
Process p = Runtime.getRuntime().exec("su");
BufferedReader reader = new BufferedReader(p.getInputStream());
StringBuilder out = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
out.append(line); // add everything to StringBuilder
// here you can have your logic of comparison.
if(line.toString().equals(".")) {
// do something
}
}
} catch(IOException e) {
e.printStackTrace();
} catch(InterruptedException e) {
e.printStackTrace();
}
I am new to Android development, and I try to access to the internal terminal (/bin/bash, ...) of Android phone using a java method.
Do you know if such java method exist?
Thanks
You can use Runtime and Process to achieve your task.
private static String executeCommand(String command) {
Process process = null;
BufferedReader reader = null;
String result = "";
try {
String line;
process = Runtime.getRuntime().exec(command);
reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
while ((line = reader.readLine()) != null)
result += line + "\n";
} catch (final Exception e) {
e.printStackTrace();
} finally {
try {
if (reader != null)
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (process != null)
process.destroy();
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}
Where command is any available terminal commands like PING 8.8.8.8
I'm not entirely sure as to what you mean by "accessing the internal terminal". But if you would like to execute commands take a look at the documentation of the Runtime class.
Here's an example on how to use it.
In my Java application I am using the exec() command to call a terminal function:
p = Runtime.getRuntime().exec(command);
p.waitFor();
The call uses the zip and unzip calls. Originally I call:
zip -P password -r encrypted.zip folderIWantToZip
When I call the unzip function through java, I specify the password as the method parameter. If the correct password is specified then the call should unzip the encrypted folder:
unzip -P password encrypted.zip
I want a way to find out if the password entered is incorrect. For example, if password is correct, then the call will correctly unzip the zip file. But I notice that no exception is thrown for an incorrect password. How can I determine this?
You could read the process's ErrorStream and InputStream to determine the process output. Sample code given below
public static void main(String[] args) {
try {
String command = "zip -P password -r encrypted.zip folderIWantToZip";
Process p = Runtime.getRuntime().exec(command);
InputStream is = p.getInputStream();
int waitFor = p.waitFor();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
String line;
while ((line = reader.readLine()) != null) {
System.out.println("line:" + line);
}
is = p.getErrorStream();
reader = new BufferedReader(new InputStreamReader(is));
while ((line = reader.readLine()) != null) {
System.out.println("ErrorStream:line: " + line);
}
System.out.println("waitFor:" + waitFor);
System.out.println("exitValue:" + p.exitValue());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
You could use the exitcode to validate the process status as well but it is specific to to program. Normally zero means successfully terminated otherwise abnormal termination.
As per my comment, first thing I would do would be to capture the Process's InputStream and ErrorStream via getInputStream() and getErrorStream(), but especially the latter, the ErrorStream, and check to see what it outputs if the input is in error. Note that these would have to be done in their own thread, else you'll tie up your program. I usually use some type of StreamGobbler class for this. Also, don't ignore the int returned by p.waitFor().
e.g.,
ProcessBuilder pBuilder = new ProcessBuilder(COMMAND);
Process process = null;
try {
process = pBuilder.start();
new Thread(new StreamGobbler("Input", process.getInputStream())).start();
new Thread(new StreamGobbler("Error", process.getErrorStream())).start();
int exitValue = process.waitFor();
System.out.println("Exit Value: " + exitValue);
process.destroy();
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
if (process != null) {
process.destroy();
}
}
And:
class StreamGobbler implements Runnable {
private String name;
private Scanner scanner;
public StreamGobbler(String name, InputStream inputStream) {
this.name = name;
scanner = new Scanner(inputStream);
}
#Override
public void run() {
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
System.out.println(name + ": " + line); // or better, log the line
}
scanner.close();
}
}
I am trying to execute a c++ code from java on a remote Windows machine. In order to deal with the remote part, I have created a Web service from where the actual command is run using Runtime.exec(). The c++ exe is not being called directly from the java code. I have a batch file that eventually calls the exe.
The problem is, both java and c++ processes hang. The java code on server side does handle the output stream and error stream. Also, the c++ code is logging everything in a file on Windows. The strange thing is that, when I remove the WS call and run the java code on server side as a standalone java program, it succeeds. Here is the java code:
public class RunCPlusPlusExecutable {
public int runExecutable() {
int exitValue = 0;
try {
Process p = null;
Runtime rt = Runtime.getRuntime();
System.out.println("About to execute" + this + rt);
p = rt.exec("c:/temp/execcplusplus.bat");
System.out.println("Process HashCode=" + p.hashCode());
StreamProcessor errorHandler = new StreamProcessor(p.getErrorStream(), "Error");
StreamProcessor outputHandler = new StreamProcessor(p.getInputStream(), "Output");
errorHandler.start();
outputHandler.start();
exitValue = p.waitFor();
System.out.println("Exit value : " + exitValue);
if (exitValue == 0)
System.out.println("SUCCESS");
else
System.out.println("FAILURE");
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (Exception e) {
}
return exitValue;
}
class StreamProcessor extends Thread {
private InputStream is = null;
private String type = null;
private InputStreamReader isr = null;
private BufferedReader br = null;
private FileWriter writer = null;
private BufferedWriter out = null;
StreamProcessor(InputStream is, String type) {
this.is = is;
this.type = type;
}
public void run() {
try {
isr = new InputStreamReader(is);
br = new BufferedReader(isr);
writer = new FileWriter("*******path to log file********");
out = new BufferedWriter(writer);
String line = null;
while ((line = br.readLine()) != null) {
Date date = new Date();
out.write("[" + type + "]: " + date + " : " + line);
out.newLine();
}
writer.flush();
} catch (IOException ioe) {
ioe.printStackTrace();
} finally {
try {
if (br != null)
br.close();
if (isr != null)
isr.close();
if (out != null)
out.close();
if (writer != null)
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
Any idea what is causing the problem and how to debug it? Please note that I won't be able to debug the c++ code.
Thanks
Update 1:
Here are some more details...
The WS server is running from some admin user. And I have been running the standalone java program from some other user.
*It seems that the c++ executable is giving referenced memory error while executing from WS call. There are pop-ups citing the error with OK and Cancel buttons. *
Update 2:
The tomcat server where the WS is deployed is running as a Windows NT service. Can that be the cause of the error? If yes, how to resolve this?
I want to create diff of two files. I tried searching for code in Java that does it, but didnt find any simple code/ utility code for this. Hence, I thought if I can somehow run linux diff/sdiff command from my java code and make it return a file that stores the diff then it would be great.
Suppose there are two files fileA and fileB. I should be able to store their diff in a file called fileDiff through my java code. Then fetching data from fileDiff would be no big deal.
You can use java.lang.Runtime.exec to run simple code. This gives you back a Process and you can read its standard output directly without having to temporarily store the output on disk.
For example, here's a complete program that will showcase how to do it:
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class testprog {
public static void main(String args[]) {
String s;
Process p;
try {
p = Runtime.getRuntime().exec("ls -aF");
BufferedReader br = new BufferedReader(
new InputStreamReader(p.getInputStream()));
while ((s = br.readLine()) != null)
System.out.println("line: " + s);
p.waitFor();
System.out.println ("exit: " + p.exitValue());
p.destroy();
} catch (Exception e) {}
}
}
When compiled and run, it outputs:
line: ./
line: ../
line: .classpath*
line: .project*
line: bin/
line: src/
exit: 0
as expected.
You can also get the error stream for the process standard error, and output stream for the process standard input, confusingly enough. In this context, the input and output are reversed since it's input from the process to this one (i.e., the standard output of the process).
If you want to merge the process standard output and error from Java (as opposed to using 2>&1 in the actual command), you should look into ProcessBuilder.
You can also write a shell script file and invoke that file from the java code. as shown below
{
Process proc = Runtime.getRuntime().exec("./your_script.sh");
proc.waitFor();
}
Write the linux commands in the script file, once the execution is over you can read the diff file in Java.
The advantage with this approach is you can change the commands with out changing java code.
You need not store the diff in a 3rd file and then read from in. Instead you make use of the Runtime.exec
Process p = Runtime.getRuntime().exec("diff fileA fileB");
BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((s = stdInput.readLine()) != null) {
System.out.println(s);
}
try to use unix4j. it s about a library in java to run linux command. for instance if you got a command like:
cat test.txt | grep "Tuesday" | sed "s/kilogram/kg/g" | sort
in this program will become:
Unix4j.cat("test.txt").grep("Tuesday").sed("s/kilogram/kg/g").sort();
You can call run-time commands from java for both Windows and Linux.
import java.io.*;
public class Test{
public static void main(String[] args)
{
try
{
Process process = Runtime.getRuntime().exec("pwd"); // for Linux
//Process process = Runtime.getRuntime().exec("cmd /c dir"); //for Windows
process.waitFor();
BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line;
while ((line=reader.readLine())!=null)
{
System.out.println(line);
}
}
catch(Exception e)
{
System.out.println(e);
}
finally
{
process.destroy();
}
}
}
Hope it Helps.. :)
Runtime run = Runtime.getRuntime();
//The best possible I found is to construct a command which you want to execute
//as a string and use that in exec. If the batch file takes command line arguments
//the command can be constructed a array of strings and pass the array as input to
//the exec method. The command can also be passed externally as input to the method.
Process p = null;
String cmd = "ls";
try {
p = run.exec(cmd);
p.getErrorStream();
p.waitFor();
}
catch (IOException e) {
e.printStackTrace();
System.out.println("ERROR.RUNNING.CMD");
}finally{
p.destroy();
}
The suggested solutions could be optimized using commons.io, handling the error stream, and using Exceptions. I would suggest to wrap like this for use in Java 8 or later:
public static List<String> execute(final String command) throws ExecutionFailedException, InterruptedException, IOException {
try {
return execute(command, 0, null, false);
} catch (ExecutionTimeoutException e) { return null; } /* Impossible case! */
}
public static List<String> execute(final String command, final long timeout, final TimeUnit timeUnit) throws ExecutionFailedException, ExecutionTimeoutException, InterruptedException, IOException {
return execute(command, 0, null, true);
}
public static List<String> execute(final String command, final long timeout, final TimeUnit timeUnit, boolean destroyOnTimeout) throws ExecutionFailedException, ExecutionTimeoutException, InterruptedException, IOException {
Process process = new ProcessBuilder().command("bash", "-c", command).start();
if(timeUnit != null) {
if(process.waitFor(timeout, timeUnit)) {
if(process.exitValue() == 0) {
return IOUtils.readLines(process.getInputStream(), StandardCharsets.UTF_8);
} else {
throw new ExecutionFailedException("Execution failed: " + command, process.exitValue(), IOUtils.readLines(process.getInputStream(), StandardCharsets.UTF_8));
}
} else {
if(destroyOnTimeout) process.destroy();
throw new ExecutionTimeoutException("Execution timed out: " + command);
}
} else {
if(process.waitFor() == 0) {
return IOUtils.readLines(process.getInputStream(), StandardCharsets.UTF_8);
} else {
throw new ExecutionFailedException("Execution failed: " + command, process.exitValue(), IOUtils.readLines(process.getInputStream(), StandardCharsets.UTF_8));
}
}
}
public static class ExecutionFailedException extends Exception {
private static final long serialVersionUID = 1951044996696304510L;
private final int exitCode;
private final List<String> errorOutput;
public ExecutionFailedException(final String message, final int exitCode, final List<String> errorOutput) {
super(message);
this.exitCode = exitCode;
this.errorOutput = errorOutput;
}
public int getExitCode() {
return this.exitCode;
}
public List<String> getErrorOutput() {
return this.errorOutput;
}
}
public static class ExecutionTimeoutException extends Exception {
private static final long serialVersionUID = 4428595769718054862L;
public ExecutionTimeoutException(final String message) {
super(message);
}
}
if the opening in windows
try {
//chm file address
String chmFile = System.getProperty("user.dir") + "/chm/sample.chm";
Desktop.getDesktop().open(new File(chmFile));
} catch (IOException ex) {
Logger.getLogger(Frame.class.getName()).log(Level.SEVERE, null, ex);
{
JOptionPane.showMessageDialog(null, "Terjadi Kesalahan", "Error", JOptionPane.WARNING_MESSAGE);
}
}
ProcessBuilder processBuilder = new ProcessBuilder();
// -- Linux --
// Run a shell command
processBuilder.command("bash", "-c", "ls /home/kk/");
// Run a shell script
//processBuilder.command("path/to/hello.sh");
// -- Windows --
// Run a command
//processBuilder.command("cmd.exe", "/c", "dir C:\\Users\\kk");
// Run a bat file
//processBuilder.command("C:\\Users\\kk\\hello.bat");
try {
Process process = processBuilder.start();
StringBuilder output = new StringBuilder();
BufferedReader reader = new BufferedReader(
new InputStreamReader(process.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
output.append(line + "\n");
}
int exitVal = process.waitFor();
if (exitVal == 0) {
System.out.println("Success!");
System.out.println(output);
System.exit(0);
} else {
//abnormal...
}
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}