com.sshtools.server.vsession.commands.os.AbstractOSCommand Maven / Gradle / Ivy
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Support for a virtual sessions, custom command execution etc.
package com.sshtools.server.vsession.commands.os;
/*-
* #%L
* Virtual Sessions
* %%
* Copyright (C) 2002 - 2024 JADAPTIVE Limited
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.pty4j.PtyProcess;
import com.pty4j.PtyProcessBuilder;
import com.pty4j.WinSize;
import com.sshtools.common.logger.Log;
import com.sshtools.common.permissions.PermissionDeniedException;
import com.sshtools.common.ssh.Channel;
import com.sshtools.common.ssh.ChannelEventListener;
import com.sshtools.common.util.IOUtils;
import com.sshtools.server.vsession.ShellCommand;
import com.sshtools.server.vsession.UsageException;
import com.sshtools.server.vsession.VirtualConsole;
import com.sshtools.server.vsession.VirtualShellNG;
import com.sshtools.server.vsession.VirtualShellNG.WindowSizeChangeListener;
public class AbstractOSCommand extends ShellCommand {
public AbstractOSCommand(String name, String subsystem, String signature, String description) {
super(name, subsystem, signature, description);
}
private PtyProcess pty;
private Map env;
private File directory;
@Override
public void run(String[] args, VirtualConsole console)
throws IOException, PermissionDeniedException, UsageException {
runCommand(null, Arrays.asList(Arrays.copyOfRange(args, 1, args.length)), console);
}
public Map getEnv() {
return env;
}
public void setEnv(Map env) {
this.env = env;
}
public File getDirectory() {
return directory;
}
public void setDirectory(File directory) {
this.directory = directory;
}
private void runCommand(String cmd, List cmdArgs,
VirtualConsole console) throws IOException {
List args = configureCommand(cmd, cmdArgs, console);
if (cmd == null) {
cmd = "";
} else {
while (cmd.startsWith("/")) {
cmd = cmd.substring(1);
}
}
Map penv = this.env == null ? new HashMap(System.getenv()) : new HashMap(this.env);
penv.put("TERM", console.getTerminal().getType());
var builder = new PtyProcessBuilder(args.toArray(new String[0]));
if(directory != null)
builder.setDirectory(directory.getAbsolutePath());
builder.setConsole(false);
builder.setEnvironment(env);
pty = builder.start();
final InputStream in = pty.getInputStream();
final OutputStream out = pty.getOutputStream();
setScreenSize(console.getTerminal().getWidth(),
console.getTerminal().getHeight());
// Listen for window size changes
VirtualShellNG shell = (VirtualShellNG) console.getSessionChannel();
WindowSizeChangeListener listener = new WindowSizeChangeListener() {
public void newSize(int rows, int cols) {
setScreenSize(cols, rows);
}
};
shell.addWindowSizeChangeListener(listener);
console.getSessionChannel().enableRawMode();
console.getSessionChannel().addEventListener(new ChannelEventListener() {
@Override
public void onChannelDataIn(Channel channel, ByteBuffer buffer) {
byte[] tmp = new byte[buffer.remaining()];
buffer.get(tmp);
try {
out.write(tmp);
out.flush();
} catch (IOException e) {
Log.error("Error writing data to pty", e);
IOUtils.closeStream(out);
IOUtils.closeStream(in);
}
}
});
try {
IOUtils.copy(in, console.getSessionChannel().getOutputStream());
out.close();
int result = pty.waitFor();
if (result > 0) {
throw new IOException("System command exited with error " + result);
}
} catch (Exception e) {
} finally {
console.getSessionChannel().disableRawMode();
}
}
protected List configureCommand(String cmd, List cmdArgs, VirtualConsole console) throws IOException {
List args = new ArrayList<>();
String shellCommand = findCommand(getName());
if(shellCommand == null)
throw new IOException("Cannot find command " + getName());
args.add(shellCommand);
if(cmdArgs!=null) {
args.addAll(cmdArgs);
}
return args;
}
protected String findCommand(String command, String... places) {
String stdbuf = execAndCapture("which", command);
if (stdbuf == null) {
for (String place : places) {
File f = new File(place);
if (f.exists()) {
stdbuf = f.getAbsolutePath();
break;
}
}
}
if (stdbuf != null) {
while (stdbuf.endsWith("\n")) {
stdbuf = stdbuf.substring(0, stdbuf.length() - 1);
}
}
return stdbuf;
}
private void setScreenSize(int width, int height) {
try {
pty.setWinSize(new WinSize(width, height));
} catch (Exception e) {
Log.warn(String.format("Could not set new terminal size of pty to %d x %d.", width, height));
}
}
private final static String execAndCapture(String... args) {
try {
ProcessBuilder builder = new ProcessBuilder(args);
builder.redirectErrorStream();
Process process = builder.start();
ByteArrayOutputStream out = new ByteArrayOutputStream();
IOUtils.copy(process.getInputStream(), out);
int ret = process.waitFor();
if (ret == 0) {
return new String(out.toByteArray());
}
throw new IOException("Got non-zero return status.");
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}