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Improve Timeout and Error Handling v2 #41

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aa8d863
Update PowerShell.java
Harinus Apr 27, 2018
bd4cae1
Update PowerShellCommandProcessor.java
Harinus Apr 27, 2018
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160 changes: 131 additions & 29 deletions src/main/java/com/profesorfalken/jpowershell/PowerShell.java
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Original file line number Diff line number Diff line change
Expand Up @@ -17,12 +17,19 @@

import java.io.*;
import java.nio.charset.Charset;
import java.time.Instant;
import java.util.Date;
import java.util.Map;
import java.util.concurrent.*;
import java.util.logging.Level;
import java.util.logging.Logger;

//JNA only!
//import java.lang.reflect.Field;
//import com.sun.jna.Pointer;
//import com.sun.jna.platform.win32.Kernel32;
//import com.sun.jna.platform.win32.WinNT;

/**
* Allows to open a session into PowerShell console and launch different
* commands.<br>
Expand All @@ -44,6 +51,7 @@ public class PowerShell implements AutoCloseable {
// Threaded session variables
private boolean closed = false;
private ExecutorService threadpool;
private boolean blocked = false;

//Default PowerShell executable path
private static final String DEFAULT_WIN_EXECUTABLE = "powershell.exe";
Expand All @@ -57,6 +65,7 @@ public class PowerShell implements AutoCloseable {

// Variables for script mode
private boolean scriptMode = false;
private File tmpFile;
public static final String END_SCRIPT_STRING = "--END-JPOWERSHELL-SCRIPT--";

// Private constructor.
Expand Down Expand Up @@ -157,6 +166,7 @@ public static PowerShell openSession() throws PowerShellNotAvailableException {
* @throws PowerShellNotAvailableException if PowerShell is not installed in the system
*/
public static PowerShell openSession(String customPowerShellExecutablePath) throws PowerShellNotAvailableException {
@SuppressWarnings("resource")
PowerShell powerShell = new PowerShell();

// Start with default configuration
Expand All @@ -177,12 +187,16 @@ public static PowerShell openSession(String customPowerShellExecutablePath) thro
* @return PowerShellResponse the information returned by powerShell
*/
public PowerShellResponse executeCommand(String command) {
Callable<String> commandProcessor = new PowerShellCommandProcessor("standard", p.getInputStream(), this.maxWait,
Instant instant = Instant.now();
long timeStampMillis = instant.toEpochMilli();

Callable<String> commandProcessor = new PowerShellCommandProcessor("standard", p.getInputStream(),
this.waitPause, this.scriptMode);
Callable<String> commandProcessorError = new PowerShellCommandProcessor("error", p.getErrorStream(),
(this.maxWait + this.waitPause + 100) /*standard processor should always timeout first!*/, this.waitPause, false);
this.waitPause, this.scriptMode);

String commandOutput = "";
String commandError = "";
boolean isError = false;
boolean timeout = false;

Expand All @@ -196,31 +210,66 @@ public PowerShellResponse executeCommand(String command) {
// Launch command
commandWriter.println(command);

try {
while (!result.isDone() && !resultError.isDone()) {
Thread.sleep(this.waitPause);
}
if (result.isDone()) {
if (((PowerShellCommandProcessor) commandProcessor).isTimeout()) {
timeout = true;
} else {
commandOutput = result.get();
}
} else {
isError = true;
commandOutput = resultError.get();
}
} catch (InterruptedException | ExecutionException ex) {
Logger.getLogger(PowerShell.class.getName()).log(Level.SEVERE,
"Unexpected error when processing PowerShell command", ex);
} finally {
// issue #2. Close and cancel processors/threads - Thanks to r4lly
// for helping me here
((PowerShellCommandProcessor) commandProcessor).close();
((PowerShellCommandProcessor) commandProcessorError).close();
}

return new PowerShellResponse(isError, commandOutput, timeout);
long elapsedTime = 0;

try {
while ((!result.isDone() || !resultError.isDone()) && (elapsedTime < maxWait)) {

//wait for both futures to be done or timeout
Thread.sleep(this.waitPause);
elapsedTime = Instant.now().toEpochMilli() - timeStampMillis;
}

if (elapsedTime >= maxWait) {
// Command timed out during execution, but may have some output
timeout = true;
commandOutput = result.get(waitPause, TimeUnit.MILLISECONDS);
commandOutput += resultError.get(waitPause, TimeUnit.MILLISECONDS);

} else {

//get the output (read is already done)
commandOutput = result.get();
commandError = resultError.get();

if(commandError.equals("")) {
//Command finished successfully
} else {
//Command failed
isError = true;
commandOutput = commandError;
}

}

if(this.scriptMode && !timeout && !isError) {
//Delete temp file if execution was successful
tmpFile.delete();
}

} catch (InterruptedException ex) {
isError = true;
timeout = true;
this.blocked = true;
Logger.getLogger(PowerShell.class.getName()).log(Level.SEVERE,
"Unexpected interrupt while processing PowerShell command", ex);
Thread.currentThread().interrupt();
} catch (ExecutionException ex) {
isError = true;
Logger.getLogger(PowerShell.class.getName()).log(Level.SEVERE,
"Unexpected error when processing PowerShell command", ex);
} catch (TimeoutException e) {
Logger.getLogger(PowerShell.class.getName()).log(Level.WARNING,
"Failed to read data due to timeout, close will be forced!");
this.blocked = true;
} finally {
// issue #2. Close and cancel processors/threads - Thanks to r4lly
// for helping me here
((PowerShellCommandProcessor) commandProcessor).close();
((PowerShellCommandProcessor) commandProcessorError).close();
}

return new PowerShellResponse(isError, commandOutput, timeout);
}

/**
Expand Down Expand Up @@ -250,7 +299,7 @@ public static PowerShellResponse executeSingleCommand(String command) {
private File createWriteTempFile(BufferedReader srcReader) {

BufferedWriter tmpWriter = null;
File tmpFile = null;
tmpFile = null;

try {

Expand All @@ -267,7 +316,10 @@ private File createWriteTempFile(BufferedReader srcReader) {
}

// Add end script line
tmpWriter.write("$host.ui.WriteErrorLine('" + END_SCRIPT_STRING + "')");
tmpWriter.newLine();
tmpWriter.write("Write-Host \"" + END_SCRIPT_STRING + "\"");

} catch (IOException ioex) {
Logger.getLogger(PowerShell.class.getName()).log(Level.SEVERE,
"Unexpected error while writing temporary PowerShell script", ioex);
Expand Down Expand Up @@ -344,7 +396,7 @@ public PowerShellResponse executeScript(BufferedReader srcReader) {
* @param params the parameters of the script
* @return response with the output of the command
*/
private PowerShellResponse executeScript(BufferedReader srcReader, String params) {
public PowerShellResponse executeScript(BufferedReader srcReader, String params) {

if (srcReader != null) {
File tmpFile = createWriteTempFile(srcReader);
Expand All @@ -366,6 +418,56 @@ private PowerShellResponse executeScript(BufferedReader srcReader, String params
*/
@Override
public void close() {

if (blocked) {
Logger.getLogger(PowerShell.class.getName()).log(Level.INFO,
"Shell is blocked, closing of PowerShell will be forced!");

if (System.getProperty("java.version").startsWith("1.")) {
System.out.println("PID unknown, no Java 9 or higher, can not do anything to kill the child processes, maybe use jna workaround?");
//p.destroyForcibly(); //will not kill the childs!

boolean jna = false;

if (jna == true) {
// int pid = -1;
//
// Field f;
// try {
// f = p.getClass().getDeclaredField("handle");
// f.setAccessible(true);
// long handLong = f.getLong(p);
//
// Kernel32 kernel = Kernel32.INSTANCE;
// WinNT.HANDLE handle = new WinNT.HANDLE();
// handle.setPointer(Pointer.createConstant(handLong));
// pid = kernel.GetProcessId(handle);
//
// } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e1) {
// Logger.getLogger(PowerShell.class.getName()).log(Level.SEVERE,
// "Unexpected error while getting process handle", e1);
// }
//
// Logger.getLogger(PowerShell.class.getName()).log(Level.INFO, "Killing process with PID: " + pid);
//
// try {
// Runtime.getRuntime().exec("taskkill.exe /f /PID " + pid + " /T");
// this.closed = true;
// } catch (IOException e) {
// Logger.getLogger(PowerShell.class.getName()).log(Level.SEVERE,
// "Unexpected error while killing powershell process", e);
// }
}
} else {
//Compile with Java 9 required for this!
// p.descendants().forEach((p) -> {
// Logger.getLogger(PowerShell.class.getName()).log(Level.INFO, "Killing zombie process with PID: " + p.pid());
// p.destroyForcibly();
// });
}

}

if (!this.closed) {
try {
Future<String> closeTask = threadpool.submit(() -> {
Expand Down
39 changes: 5 additions & 34 deletions src/main/java/com/profesorfalken/jpowershell/PowerShellCommandProcessor.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -37,14 +37,11 @@ class PowerShellCommandProcessor implements Callable<String> {
private final BufferedReader reader;
private final String name;

private final int waitPause;

private boolean closed = false;
private boolean timeout = false;

private boolean scriptMode = false;

private final long maxWait;
private final int waitPause;


/**
* Constructor that takes the output and the input of the PowerShell session
*
Expand All @@ -54,11 +51,10 @@ class PowerShellCommandProcessor implements Callable<String> {
* @param waitPause long the wait pause in milliseconds
* @param scriptMode boolean indicates if the command executes a script
*/
public PowerShellCommandProcessor(String name, InputStream inputStream, long maxWait, int waitPause, boolean scriptMode) {
public PowerShellCommandProcessor(String name, InputStream inputStream, int waitPause, boolean scriptMode) {
this.reader = new BufferedReader(new InputStreamReader(
inputStream));
this.name = name;
this.maxWait = maxWait;
this.waitPause = waitPause;
this.scriptMode = scriptMode;
}
Expand All @@ -73,9 +69,7 @@ public String call() throws IOException, InterruptedException {
StringBuilder powerShellOutput = new StringBuilder();

try {
if (startReading()) {
readData(powerShellOutput);
}
readData(powerShellOutput);
} catch (IOException ioe) {
Logger.getLogger(PowerShell.class.getName()).log(Level.SEVERE, "Unexpected error reading PowerShell output", ioe);
return ioe.getMessage();
Expand Down Expand Up @@ -113,21 +107,6 @@ private void readData(StringBuilder powerShellOutput) throws IOException {
}
}

//Checks when we can start reading the output. Timeout if it takes too long in order to avoid hangs
private boolean startReading() throws IOException, InterruptedException {
int timeWaiting = 0;

while (!this.reader.ready()) {
Thread.sleep(this.waitPause);
timeWaiting += this.waitPause;
if ((timeWaiting > this.maxWait) || this.closed) {
this.timeout = timeWaiting > this.maxWait;
return false;
}
}
return true;
}

//Checks when we the reader can continue to read.
private boolean continueReading() throws IOException, InterruptedException {
Thread.sleep(this.waitPause);
Expand All @@ -141,12 +120,4 @@ public void close() {
this.closed = true;
}

/**
* Return if the execution finished with a timeout
*
* @return name of the command processor
*/
public boolean isTimeout() {
return this.timeout;
}
}