com.google.gerrit.sshd.BaseCommand Maven / Gradle / Ivy
// Copyright (C) 2009 The Android Open Source Project
//
// Licensed 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 com.google.gerrit.sshd;
import static java.nio.charset.StandardCharsets.UTF_8;
import com.google.common.base.Joiner;
import com.google.common.flogger.FluentLogger;
import com.google.common.util.concurrent.Atomics;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.entities.Project;
import com.google.gerrit.extensions.annotations.PluginName;
import com.google.gerrit.extensions.registration.DynamicMap;
import com.google.gerrit.extensions.restapi.AuthException;
import com.google.gerrit.server.AccessPath;
import com.google.gerrit.server.CurrentUser;
import com.google.gerrit.server.DynamicOptions;
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.RequestCleanup;
import com.google.gerrit.server.git.ProjectRunnable;
import com.google.gerrit.server.git.WorkQueue.CancelableRunnable;
import com.google.gerrit.server.permissions.GlobalPermission;
import com.google.gerrit.server.permissions.PermissionBackend;
import com.google.gerrit.server.permissions.PermissionBackendException;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gerrit.server.project.NoSuchProjectException;
import com.google.gerrit.sshd.SshScope.Context;
import com.google.gerrit.util.cli.CmdLineParser;
import com.google.gerrit.util.cli.EndOfOptionsHandler;
import com.google.inject.Inject;
import com.google.inject.Injector;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InterruptedIOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.sshd.common.SshException;
import org.apache.sshd.common.channel.exception.SshChannelClosedException;
import org.apache.sshd.server.Environment;
import org.apache.sshd.server.ExitCallback;
import org.apache.sshd.server.channel.ChannelSession;
import org.apache.sshd.server.command.Command;
import org.kohsuke.args4j.Argument;
import org.kohsuke.args4j.CmdLineException;
import org.kohsuke.args4j.Option;
public abstract class BaseCommand implements Command {
private static final FluentLogger logger = FluentLogger.forEnclosingClass();
public static final Charset ENC = UTF_8;
private static final int PRIVATE_STATUS = 1 << 30;
static final int STATUS_CANCEL = PRIVATE_STATUS | 1;
static final int STATUS_NOT_FOUND = PRIVATE_STATUS | 2;
public static final int STATUS_NOT_ADMIN = PRIVATE_STATUS | 3;
@SuppressWarnings("unused") // unused here, but triggers logic in EndOfOptionsHandler
@Option(name = "--", usage = "end of options", handler = EndOfOptionsHandler.class)
private boolean endOfOptions;
protected InputStream in;
protected OutputStream out;
protected OutputStream err;
protected ExitCallback exit;
@Inject protected CurrentUser user;
@Inject private SshScope sshScope;
@Inject private CmdLineParser.Factory cmdLineParserFactory;
@Inject protected RequestCleanup cleanup;
@Inject @CommandExecutor private ScheduledThreadPoolExecutor executor;
@Inject private PermissionBackend permissionBackend;
@Inject private SshScope.Context context;
/** Commands declared by a plugin can be scoped by the plugin name. */
@Inject(optional = true)
@PluginName
private String pluginName;
@Inject protected Injector injector;
@Inject protected DynamicMap dynamicBeans;
/** The task, as scheduled on a worker thread. */
private final AtomicReference> task;
/** Text of the command line which lead up to invoking this instance. */
private String commandName = "";
/** Unparsed command line options. */
private String[] argv;
/** trimmed command line arguments. */
private String[] trimmedArgv;
public BaseCommand() {
task = Atomics.newReference();
}
@Override
public void setInputStream(InputStream in) {
this.in = in;
}
@Override
public void setOutputStream(OutputStream out) {
this.out = out;
}
@Override
public void setErrorStream(OutputStream err) {
this.err = err;
}
@Override
public void setExitCallback(ExitCallback callback) {
this.exit = callback;
}
@Nullable
protected String getPluginName() {
return pluginName;
}
protected String getName() {
return commandName;
}
void setName(String prefix) {
this.commandName = prefix;
}
public String[] getArguments() {
return argv;
}
public void setArguments(String[] argv) {
this.argv = argv;
}
/**
* Trim the argument if it is spanning multiple lines.
*
* @return the arguments where all the multiple-line fields are trimmed.
*/
protected String[] getTrimmedArguments() {
if (trimmedArgv == null && argv != null) {
trimmedArgv = new String[argv.length];
for (int i = 0; i < argv.length; i++) {
String arg = argv[i];
int indexOfMultiLine = arg.indexOf("\n");
if (indexOfMultiLine > -1) {
arg = arg.substring(0, indexOfMultiLine) + " [trimmed]";
}
trimmedArgv[i] = arg;
}
}
return trimmedArgv;
}
@Override
public void destroy(ChannelSession channel) {
Future future = task.getAndSet(null);
if (future != null && !future.isDone()) {
future.cancel(true);
}
}
/**
* Pass all state into the command, then run its start method.
*
* This method copies all critical state, like the input and output streams, into the supplied
* command. The caller must still invoke {@code cmd.start()} if wants to pass control to the
* command.
*
* @param cmd the command that will receive the current state.
*/
protected void provideStateTo(Command cmd) {
cmd.setInputStream(in);
cmd.setOutputStream(out);
cmd.setErrorStream(err);
cmd.setExitCallback(exit);
}
/**
* Parses the command line argument, injecting parsed values into fields.
*
*
This method must be explicitly invoked to cause a parse.
*
* @param pluginOptions which helps to define and parse options provided from plugins
* @throws UnloggedFailure if the command line arguments were invalid.
* @see Option
* @see Argument
*/
protected void parseCommandLine(DynamicOptions pluginOptions) throws UnloggedFailure {
parseCommandLine(this, pluginOptions);
}
/**
* Parses the command line argument, injecting parsed values into fields.
*
*
This method must be explicitly invoked to cause a parse.
*
* @param options object whose fields declare Option and Argument annotations to describe the
* parameters of the command. Usually {@code this}.
* @param pluginOptions which helps to define and parse options provided from plugins
* @throws UnloggedFailure if the command line arguments were invalid.
* @see Option
* @see Argument
*/
protected void parseCommandLine(Object options, DynamicOptions pluginOptions)
throws UnloggedFailure {
final CmdLineParser clp = newCmdLineParser(options);
pluginOptions.setBean(options);
pluginOptions.startLifecycleListeners();
pluginOptions.parseDynamicBeans(clp);
pluginOptions.setDynamicBeans();
pluginOptions.onBeanParseStart();
try {
clp.parseArgument(argv);
} catch (IllegalArgumentException | CmdLineException err) {
if (!clp.wasHelpRequestedByOption()) {
throw new UnloggedFailure(1, "fatal: " + err.getMessage());
}
}
if (clp.wasHelpRequestedByOption()) {
StringWriter msg = new StringWriter();
clp.printDetailedUsage(commandName, msg);
msg.write(usage());
throw new UnloggedFailure(1, msg.toString());
}
pluginOptions.onBeanParseEnd();
}
protected String usage() {
return "";
}
/** Construct a new parser for this command's received command line. */
protected CmdLineParser newCmdLineParser(Object options) {
return cmdLineParserFactory.create(options);
}
/**
* Spawn a function into its own thread.
*
*
Typically this should be invoked within {@link Command#start(ChannelSession, Environment)},
* such as:
*
*
* startThread(new CommandRunnable() {
* public void run() throws Exception {
* runImp();
* }
* },
* accessPath);
*
*
* If the function throws an exception, it is translated to a simple message for the client, a
* non-zero exit code, and the stack trace is logged.
*
* @param thunk the runnable to execute on the thread, performing the command's logic.
* @param accessPath the path used by the end user for running the SSH command
*/
protected void startThread(final CommandRunnable thunk, AccessPath accessPath) {
final TaskThunk tt = new TaskThunk(thunk, accessPath);
if (isAdminHighPriorityCommand()) {
// Admin commands should not block the main work threads (there
// might be an interactive shell there), nor should they wait
// for the main work threads.
//
new Thread(tt, tt.toString()).start();
} else {
task.set(executor.submit(tt));
}
}
private boolean isAdminHighPriorityCommand() {
if (getClass().getAnnotation(AdminHighPriorityCommand.class) != null) {
try {
permissionBackend.user(user).check(GlobalPermission.ADMINISTRATE_SERVER);
return true;
} catch (AuthException | PermissionBackendException e) {
return false;
}
}
return false;
}
/**
* Terminate this command and return a result code to the remote client.
*
*
Commands should invoke this at most once. Once invoked, the command may lose access to
* request based resources as any callbacks previously registered with {@link RequestCleanup} will
* fire.
*
* @param rc exit code for the remote client.
*/
protected void onExit(int rc) {
exit.onExit(rc);
if (cleanup != null) {
cleanup.run();
}
}
/** Wrap the supplied output stream in a UTF-8 encoded PrintWriter. */
protected static PrintWriter toPrintWriter(OutputStream o) {
return new PrintWriter(new BufferedWriter(new OutputStreamWriter(o, ENC)));
}
private int handleError(Throwable e) {
if ((e.getClass() == IOException.class && "Pipe closed".equals(e.getMessage()))
|| //
(e.getClass() == SshException.class && "Already closed".equals(e.getMessage()))
|| //
e.getClass() == InterruptedIOException.class) {
// This is sshd telling us the client just dropped off while
// we were waiting for a read or a write to complete. Either
// way its not really a fatal error. Don't log it.
//
return 127;
}
if (!(e instanceof UnloggedFailure)) {
final StringBuilder m = new StringBuilder();
m.append("Internal server error");
if (user.isIdentifiedUser()) {
final IdentifiedUser u = user.asIdentifiedUser();
m.append(" (user ");
m.append(u.getUserName().orElse(null));
m.append(" account ");
m.append(u.getAccountId());
m.append(")");
}
m.append(" during ");
m.append(context.getCommandLine());
logCauseIfRelevant(e, m);
}
if (e instanceof Failure) {
final Failure f = (Failure) e;
try {
err.write((f.getMessage() + "\n").getBytes(ENC));
err.flush();
} catch (IOException e2) {
// Ignored
} catch (RuntimeException e2) {
logger.atWarning().withCause(e2).log("Cannot send failure message to client");
}
return f.exitCode;
}
try {
err.write("fatal: internal server error\n".getBytes(ENC));
err.flush();
} catch (IOException e2) {
// Ignored
} catch (RuntimeException e2) {
logger.atWarning().withCause(e2).log("Cannot send internal server error message to client");
}
return 128;
}
private void logCauseIfRelevant(Throwable e, StringBuilder message) {
String zeroLength = "length=0";
String streamAlreadyClosed = "stream is already closed";
boolean isZeroLength = false;
if (streamAlreadyClosed.equals(e.getMessage())) {
StackTraceElement[] stackTrace = e.getStackTrace();
isZeroLength = Arrays.stream(stackTrace).anyMatch(s -> s.toString().contains(zeroLength));
}
if (!isZeroLength) {
logger.atSevere().withCause(e).log("%s", message);
}
}
protected UnloggedFailure die(String msg) {
return new UnloggedFailure(1, "fatal: " + msg);
}
protected UnloggedFailure die(String msg, Throwable why) {
return new UnloggedFailure(1, "fatal: " + msg, why);
}
protected UnloggedFailure die(Throwable why) {
return new UnloggedFailure(1, "fatal: " + why.getMessage(), why);
}
protected void writeError(String type, String msg) {
try {
err.write((type + ": " + msg + "\n").getBytes(ENC));
} catch (IOException e) {
// Ignored
}
}
protected void enableGracefulStop() {
context.getSession().setGracefulStop(true);
}
protected String getTaskDescription() {
String[] ta = getTrimmedArguments();
if (ta != null) {
return commandName + " " + Joiner.on(" ").join(ta);
}
return commandName;
}
private String getTaskName() {
StringBuilder m = new StringBuilder();
m.append(getTaskDescription());
if (user.isIdentifiedUser()) {
IdentifiedUser u = user.asIdentifiedUser();
if (u.getUserName().isPresent()) {
m.append(" (").append(u.getUserName().get()).append(")");
}
}
return m.toString();
}
private final class TaskThunk implements CancelableRunnable, ProjectRunnable {
private final CommandRunnable thunk;
private final String taskName;
private final AccessPath accessPath;
private Project.NameKey projectName;
private TaskThunk(final CommandRunnable thunk, AccessPath accessPath) {
this.thunk = thunk;
this.taskName = getTaskName();
this.accessPath = accessPath;
}
@Override
public void cancel() {
synchronized (this) {
final Context old = sshScope.set(context);
try {
onExit(STATUS_CANCEL);
} finally {
sshScope.set(old);
}
}
}
@Override
public void run() {
synchronized (this) {
final Thread thisThread = Thread.currentThread();
final String thisName = thisThread.getName();
int rc = 0;
context.getSession().setAccessPath(accessPath);
final Context old = sshScope.set(context);
try {
context.start();
thisThread.setName("SSH " + taskName);
try {
if (thunk instanceof ProjectCommandRunnable) {
try (DynamicOptions pluginOptions = new DynamicOptions(injector, dynamicBeans)) {
((ProjectCommandRunnable) thunk).executeParseCommand(pluginOptions);
projectName = ((ProjectCommandRunnable) thunk).getProjectName();
thunk.run();
}
} else {
thunk.run();
}
} catch (NoSuchProjectException e) {
throw new UnloggedFailure(1, e.getMessage());
} catch (NoSuchChangeException e) {
throw new UnloggedFailure(1, e.getMessage() + " no such change");
}
flushIgnoreSCCE(out);
flushIgnoreSCCE(err);
} catch (Throwable e) {
flushIgnoreException(out);
flushIgnoreException(err);
rc = handleError(e);
} finally {
try {
onExit(rc);
} finally {
sshScope.set(old);
thisThread.setName(thisName);
}
}
}
}
private void flushIgnoreSCCE(OutputStream os) throws IOException {
try {
os.flush();
} catch (SshChannelClosedException e) {
// Ignore - command implementation flushed stream already
}
}
private void flushIgnoreException(OutputStream os) {
try {
os.flush();
} catch (Exception e) {
// Ignore
}
}
@Override
public String toString() {
return taskName;
}
@Override
public Project.NameKey getProjectNameKey() {
return projectName;
}
@Override
public String getRemoteName() {
return null;
}
@Override
public boolean hasCustomizedPrint() {
return false;
}
}
/** Runnable function which can throw an exception. */
@FunctionalInterface
public interface CommandRunnable {
void run() throws Exception;
}
/** Runnable function which can retrieve a project name related to the task */
public interface ProjectCommandRunnable extends CommandRunnable {
// execute parser command before running, in order to be able to retrieve
// project name
void executeParseCommand(DynamicOptions pluginOptions) throws Exception;
Project.NameKey getProjectName();
}
/** Thrown from {@link CommandRunnable#run()} with client message and code. */
public static class Failure extends Exception {
private static final long serialVersionUID = 1L;
final int exitCode;
/**
* Create a new failure.
*
* @param exitCode exit code to return the client, which indicates the failure status of this
* command. Should be between 1 and 255, inclusive.
* @param msg message to also send to the client's stderr.
*/
public Failure(int exitCode, String msg) {
this(exitCode, msg, null);
}
/**
* Create a new failure.
*
* @param exitCode exit code to return the client, which indicates the failure status of this
* command. Should be between 1 and 255, inclusive.
* @param msg message to also send to the client's stderr.
* @param why stack trace to include in the server's log, but is not sent to the client's
* stderr.
*/
public Failure(int exitCode, String msg, Throwable why) {
super(msg, why);
this.exitCode = exitCode;
}
}
/** Thrown from {@link CommandRunnable#run()} with client message and code. */
public static class UnloggedFailure extends Failure {
private static final long serialVersionUID = 1L;
/**
* Create a new failure.
*
* @param msg message to also send to the client's stderr.
*/
public UnloggedFailure(String msg) {
this(1, msg);
}
/**
* Create a new failure.
*
* @param exitCode exit code to return the client, which indicates the failure status of this
* command. Should be between 1 and 255, inclusive.
* @param msg message to also send to the client's stderr.
*/
public UnloggedFailure(int exitCode, String msg) {
this(exitCode, msg, null);
}
/**
* Create a new failure.
*
* @param exitCode exit code to return the client, which indicates the failure status of this
* command. Should be between 1 and 255, inclusive.
* @param msg message to also send to the client's stderr.
* @param why stack trace to include in the server's log, but is not sent to the client's
* stderr.
*/
public UnloggedFailure(int exitCode, String msg, Throwable why) {
super(exitCode, msg, why);
}
}
}