org.apache.sshd.common.channel.SttySupport Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.sshd.common.channel;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.util.EnumMap;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
/**
* Support for stty command on unix
*
* @author Apache MINA SSHD Project
*/
public final class SttySupport {
public static final int DEFAULT_TERMINAL_WIDTH = 80;
public static final int DEFAULT_TERMINAL_HEIGHT = 24;
public static final String SSHD_STTY_COMMAND_PROP = "sshd.sttyCommand";
public static final String DEFAULT_SSHD_STTY_COMMAND = "stty";
private static final AtomicReference STTY_COMMAND_HOLDER
= new AtomicReference<>(System.getProperty(SSHD_STTY_COMMAND_PROP, DEFAULT_SSHD_STTY_COMMAND));
private static final AtomicReference TTY_PROPS_HOLDER = new AtomicReference<>(null);
private static final AtomicLong TTY_PROPS_LAST_FETCHED_HOLDER = new AtomicLong(0L);
private SttySupport() {
throw new UnsupportedOperationException("No instance allowed");
}
public static Map getUnixPtyModes() throws IOException, InterruptedException {
return parsePtyModes(getTtyProps());
}
public static Map parsePtyModes(String stty) {
Map modes = new EnumMap<>(PtyMode.class);
for (PtyMode mode : PtyMode.MODES) {
if ((mode == PtyMode.TTY_OP_ISPEED) || (mode == PtyMode.TTY_OP_OSPEED)) {
// TODO ...
continue;
}
String str = mode.name().toLowerCase();
// Are we looking for a character?
if (str.charAt(0) == 'v') {
str = str.substring(1);
int v = findChar(stty, str);
if ((v < 0) && "reprint".equals(str)) {
v = findChar(stty, "rprnt");
}
if (v >= 0) {
modes.put(mode, v);
}
} else {
int v = findFlag(stty, str);
if (v >= 0) {
modes.put(mode, v);
}
}
}
return modes;
}
private static int findFlag(String stty, String name) {
int cur = 0;
while (cur < stty.length()) {
int idx1 = stty.indexOf(name, cur);
int idx2 = idx1 + name.length();
if (idx1 < 0) {
return -1;
}
if ((idx1 > 0) && Character.isLetterOrDigit(stty.charAt(idx1 - 1))
|| ((idx2 < stty.length()) && Character.isLetterOrDigit(stty.charAt(idx2)))) {
cur = idx2;
continue;
}
return idx1 == 0 ? 1 : stty.charAt(idx1 - 1) == '-' ? 0 : 1;
}
return -1;
}
private static int findChar(String stty, String name) {
int cur = 0;
while (cur < stty.length()) {
int idx1 = stty.indexOf(name, cur);
int idx2 = stty.indexOf('=', idx1);
int idx3 = stty.indexOf(';', idx1);
if (idx1 < 0 || idx2 < 0 || idx3 < idx2) {
// Invalid syntax
return -1;
}
if (idx1 > 0 && Character.isLetterOrDigit(stty.charAt(idx1 - 1))
|| (idx2 < stty.length() && Character.isLetterOrDigit(stty.charAt(idx2)))) {
cur = idx1 + name.length();
continue;
}
String val = stty.substring(idx2 + 1, idx3 < 0 ? stty.length() : idx3).trim();
if (val.contains("undef")) {
return -1;
}
if (val.length() == 2 && val.charAt(0) == '^') {
int v = (val.charAt(1) - 'A' + 129) % 128;
return v;
} else {
try {
return Integer.parseInt(val);
} catch (NumberFormatException e) {
// what else ?
}
}
return -1;
}
return -1;
}
/**
*
* Returns the value of "stty size" width param.
*
*
*
* Note: this method caches the value from the first time it is called in order to increase speed,
* which means that changing to size of the terminal will not be reflected in the console.
*
*
* @return The terminal width
*/
public static int getTerminalWidth() {
try {
int val = getTerminalProperty("columns");
if (val == -1) {
val = DEFAULT_TERMINAL_WIDTH;
}
return val;
} catch (Exception e) {
return DEFAULT_TERMINAL_WIDTH; // debug breakpoint
}
}
/**
*
* Returns the value of "stty size" height param.
*
*
*
* Note: this method caches the value from the first time it is called in order to increase speed,
* which means that changing to size of the terminal will not be reflected in the console.
*
*
* @return The terminal height
*/
public static int getTerminalHeight() {
try {
int val = getTerminalProperty("rows");
if (val == -1) {
val = DEFAULT_TERMINAL_HEIGHT;
}
return val;
} catch (Exception e) {
return DEFAULT_TERMINAL_HEIGHT; // debug breakpoint
}
}
public static int getTerminalProperty(String prop) throws IOException, InterruptedException {
// need to be able handle both output formats:
// speed 9600 baud; 24 rows; 140 columns;
// and:
// speed 38400 baud; rows = 49; columns = 111; ypixels = 0; xpixels = 0;
for (StringTokenizer tok = new StringTokenizer(getTtyProps(), ";\n"); tok.hasMoreTokens();) {
String str = tok.nextToken().trim();
if (str.startsWith(prop)) {
int index = str.lastIndexOf(' ');
return Integer.parseInt(str.substring(index).trim());
} else if (str.endsWith(prop)) {
int index = str.indexOf(' ');
return Integer.parseInt(str.substring(0, index).trim());
}
}
return -1;
}
public static String getTtyProps() throws IOException, InterruptedException {
// tty properties are cached so we don't have to worry too much about getting term width/height
long now = System.currentTimeMillis();
long lastFetched = TTY_PROPS_LAST_FETCHED_HOLDER.get();
if ((TTY_PROPS_HOLDER.get() == null) || ((now - lastFetched) > 1000L)) {
TTY_PROPS_HOLDER.set(stty("-a"));
TTY_PROPS_LAST_FETCHED_HOLDER.set(System.currentTimeMillis());
}
return TTY_PROPS_HOLDER.get();
}
/**
* Execute the stty command with the specified arguments against the current active terminal.
*
* @param args The command arguments
* @return The execution result
* @throws IOException If failed to execute the command
* @throws InterruptedException If interrupted while awaiting command execution
* @see #exec(String)
*/
public static String stty(String args) throws IOException, InterruptedException {
return exec("stty " + args + " < /dev/tty").trim();
}
/**
* Execute the specified command and return the output (both stdout and stderr).
*
* @param cmd The command to execute
* @return The execution result
* @throws IOException If failed to execute the command
* @throws InterruptedException If interrupted while awaiting command execution
* @see #exec(String[])
*/
public static String exec(final String cmd)
throws IOException, InterruptedException {
return exec("sh", "-c", cmd);
}
/**
* Execute the specified command and return the output (both stdout and stderr).
*
* @param cmd The command components
* @return The execution result
* @throws IOException If failed to execute the command
* @throws InterruptedException If interrupted while awaiting command execution
*/
private static String exec(String... cmd)
throws IOException, InterruptedException {
try (ByteArrayOutputStream bout = new ByteArrayOutputStream()) {
Process p = Runtime.getRuntime().exec(cmd);
copyStream(p.getInputStream(), bout);
copyStream(p.getErrorStream(), bout);
p.waitFor();
String result = new String(bout.toByteArray(), Charset.defaultCharset());
return result;
}
}
private static int copyStream(InputStream in, OutputStream bout) throws IOException {
int count = 0;
while (true) {
int c = in.read();
if (c == -1) {
return count;
}
bout.write(c);
count++;
}
}
/**
* @return The command to use to set the terminal options.
* @see #setSttyCommand(String)
*/
public static String getSttyCommand() {
return STTY_COMMAND_HOLDER.get();
}
/**
* @param cmd The command to use to set the terminal options. Defaults to {@link #DEFAULT_SSHD_STTY_COMMAND}, or the
* value of the {@link #SSHD_STTY_COMMAND_PROP} system property if not set via this method
*/
public static void setSttyCommand(String cmd) {
STTY_COMMAND_HOLDER.set(cmd);
}
}
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