org.dellroad.jct.ssh.SshUtil Maven / Gradle / Ivy
/*
* Copyright (C) 2023 Archie L. Cobbs. All rights reserved.
*/
package org.dellroad.jct.ssh;
import java.nio.charset.Charset;
import java.util.EnumMap;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Stream;
import org.apache.sshd.common.channel.PtyMode;
import org.apache.sshd.server.Environment;
import org.apache.sshd.server.Signal;
import org.jline.terminal.Attributes;
import org.jline.terminal.Size;
import org.jline.terminal.Terminal;
/**
* Utility methods relating to Apache MINA SSHD.
*/
public final class SshUtil {
private static final String ENV_LC_ALL = "LC_ALL";
private static final String ENV_LC_CTYPE = "LC_CTYPE";
private static final String ENV_LANG = "LANG";
private static final Pattern LC_TYPE_PATTERN = Pattern.compile("(?:\\p{Alpha}{2}_\\p{Alpha}{2}\\.)?([^@]+)(?:@.*)?");
private static final EnumMap CHANNEL_TO_TERMINAL_SIGNAL_MAP = new EnumMap<>(Signal.class);
private static final EnumMap TERMINAL_TO_CHANNEL_SIGNAL_MAP = new EnumMap<>(Terminal.Signal.class);
static {
CHANNEL_TO_TERMINAL_SIGNAL_MAP.put(Signal.INT, Terminal.Signal.INT);
CHANNEL_TO_TERMINAL_SIGNAL_MAP.put(Signal.QUIT, Terminal.Signal.QUIT);
CHANNEL_TO_TERMINAL_SIGNAL_MAP.put(Signal.TSTP, Terminal.Signal.TSTP);
CHANNEL_TO_TERMINAL_SIGNAL_MAP.put(Signal.CONT, Terminal.Signal.CONT);
CHANNEL_TO_TERMINAL_SIGNAL_MAP.put(Signal.WINCH, Terminal.Signal.WINCH);
CHANNEL_TO_TERMINAL_SIGNAL_MAP.forEach((key, value) -> TERMINAL_TO_CHANNEL_SIGNAL_MAP.put(value, key));
}
private static final Map> ATTR_MAP = new EnumMap<>(PtyMode.class);
static {
// Control characters
ATTR_MAP.put(PtyMode.VINTR, Attributes.ControlChar.VINTR);
ATTR_MAP.put(PtyMode.VQUIT, Attributes.ControlChar.VQUIT);
ATTR_MAP.put(PtyMode.VERASE, Attributes.ControlChar.VERASE);
ATTR_MAP.put(PtyMode.VKILL, Attributes.ControlChar.VKILL);
ATTR_MAP.put(PtyMode.VEOF, Attributes.ControlChar.VEOF);
ATTR_MAP.put(PtyMode.VEOL, Attributes.ControlChar.VEOL);
ATTR_MAP.put(PtyMode.VEOL2, Attributes.ControlChar.VEOL2);
ATTR_MAP.put(PtyMode.VSTART, Attributes.ControlChar.VSTART);
ATTR_MAP.put(PtyMode.VSTOP, Attributes.ControlChar.VSTOP);
ATTR_MAP.put(PtyMode.VSUSP, Attributes.ControlChar.VSUSP);
ATTR_MAP.put(PtyMode.VDSUSP, Attributes.ControlChar.VDSUSP);
ATTR_MAP.put(PtyMode.VREPRINT, Attributes.ControlChar.VREPRINT);
ATTR_MAP.put(PtyMode.VWERASE, Attributes.ControlChar.VWERASE);
ATTR_MAP.put(PtyMode.VLNEXT, Attributes.ControlChar.VLNEXT);
//ATTR_MAP.put(PtyMode.VFLUSH, Attributes.ControlChar.VFLUSH);
//ATTR_MAP.put(PtyMode.VSWTCH, Attributes.ControlChar.VSWTCH);
ATTR_MAP.put(PtyMode.VSTATUS, Attributes.ControlChar.VSTATUS);
ATTR_MAP.put(PtyMode.VDISCARD, Attributes.ControlChar.VDISCARD);
// Input flags
ATTR_MAP.put(PtyMode.ICRNL, Attributes.InputFlag.ICRNL);
ATTR_MAP.put(PtyMode.INLCR, Attributes.InputFlag.INLCR);
ATTR_MAP.put(PtyMode.IGNCR, Attributes.InputFlag.IGNCR);
// Output flags
ATTR_MAP.put(PtyMode.OCRNL, Attributes.OutputFlag.OCRNL);
ATTR_MAP.put(PtyMode.ONLCR, Attributes.OutputFlag.ONLCR);
ATTR_MAP.put(PtyMode.ONLRET, Attributes.OutputFlag.ONLRET);
ATTR_MAP.put(PtyMode.OPOST, Attributes.OutputFlag.OPOST);
// Local flags
ATTR_MAP.put(PtyMode.ECHO, Attributes.LocalFlag.ECHO);
ATTR_MAP.put(PtyMode.ICANON, Attributes.LocalFlag.ICANON);
ATTR_MAP.put(PtyMode.ISIG, Attributes.LocalFlag.ISIG);
}
private SshUtil() {
}
/**
* Map SSH channel signal to the corresponding {@link Terminal} signal, if able.
*
* @param signal SSH channel signal
* @return corresponding {@link Terminal} signal, if known
* @throws IllegalArgumentException if {@code signal} is null
*/
public static Optional mapSignalToTerminal(Signal signal) {
if (signal == null)
throw new IllegalArgumentException("null signal");
return Optional.of(signal).map(CHANNEL_TO_TERMINAL_SIGNAL_MAP::get);
}
/**
* Map {@link Terminal} signal to the corresponding SSH channel signal.
*
* @param signal {@link Terminal} signal
* @return corresponding SSH channel signal, if known
* @throws IllegalArgumentException if {@code signal} is null
*/
public static Optional mapTerminalToSignal(Terminal.Signal signal) {
if (signal == null)
throw new IllegalArgumentException("null signal");
return Optional.of(signal).map(TERMINAL_TO_CHANNEL_SIGNAL_MAP::get);
}
/**
* Attempt to infer the character encoding associated with an SSH connection.
*
* @param env SSH environment
* @return character encoding, if known
* @throws IllegalArgumentException if {@code env} is null
*/
public static Optional inferCharacterEncoding(Environment env) {
return Stream.of(ENV_LC_ALL, ENV_LC_CTYPE, ENV_LANG)
.map(env.getEnv()::get)
.filter(Objects::nonNull)
.map(LC_TYPE_PATTERN::matcher)
.filter(Matcher::matches)
.map(matcher -> matcher.group(1))
.map(name -> {
try {
return Charset.forName(name);
} catch (IllegalArgumentException e) {
return null;
}
})
.filter(Objects::nonNull)
.findFirst();
}
/**
* Attempt to infer the locale associated with an SSH connection.
*
* @param env SSH environment
* @return local, if known
* @throws IllegalArgumentException if {@code env} is null
*/
public static Optional inferLocale(Environment env) {
return Stream.of(ENV_LC_ALL, ENV_LC_CTYPE, ENV_LANG)
.map(env.getEnv()::get)
.filter(Objects::nonNull)
.map(Locale::new)
.findFirst();
}
/**
* Update {@link Terminal} attributes based on the given SSH connection.
*
* @param attr terminal attributes
* @param env SSH connection info
* @throws IllegalArgumentException if either parameter is null
*/
public static void updateAttributesFromEnvironment(Attributes attr, Environment env) {
if (attr == null)
throw new IllegalArgumentException("null attr");
if (env == null)
throw new IllegalArgumentException("null env");
env.getPtyModes().forEach((mode, value) -> {
final Enum attrKey = ATTR_MAP.get(mode);
if (attrKey == null)
return;
if (attrKey instanceof Attributes.ControlChar)
attr.setControlChar((Attributes.ControlChar)attrKey, value);
else if (attrKey instanceof Attributes.InputFlag)
attr.setInputFlag((Attributes.InputFlag)attrKey, value != 0);
else if (attrKey instanceof Attributes.OutputFlag)
attr.setOutputFlag((Attributes.OutputFlag)attrKey, value != 0);
else if (attrKey instanceof Attributes.LocalFlag)
attr.setLocalFlag((Attributes.LocalFlag)attrKey, value != 0);
else
throw new RuntimeException("internal error");
});
}
/**
* Update {@link Terminal} window size based on SSH environment variables.
*
* @param terminal the terminal to update
* @param env SSH connection info
* @return true if size was successfully updated
* @throws IllegalArgumentException if either parameter is null
*/
public static boolean updateSize(Terminal terminal, Environment env) {
// Validate
if (terminal == null)
throw new IllegalArgumentException("null terminal");
if (env == null)
throw new IllegalArgumentException("null env");
// Find and parse valid environment variables
final String colsString = env.getEnv().get(Environment.ENV_COLUMNS);
final String rowsString = env.getEnv().get(Environment.ENV_LINES);
if (colsString == null || rowsString == null)
return false;
final int cols;
final int rows;
try {
cols = Integer.parseInt(colsString, 10);
rows = Integer.parseInt(rowsString, 10);
} catch (IllegalArgumentException e) {
return false;
}
if (cols <= 0 || rows <= 0)
return false;
// Update size
terminal.setSize(new Size(cols, rows));
return true;
}
}
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