// 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 com.google.gerrit.server.CurrentUser;
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;
import com.google.gerrit.server.git.WorkQueue.CancelableRunnable;
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.Provider;
import org.apache.sshd.common.SshException;
import org.apache.sshd.server.Command;
import org.apache.sshd.server.Environment;
import org.apache.sshd.server.ExitCallback;
import org.kohsuke.args4j.Argument;
import org.kohsuke.args4j.CmdLineException;
import org.kohsuke.args4j.Option;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.*;
import java.util.concurrent.Future;
public abstract class BaseCommand implements Command {
private static final Logger log = LoggerFactory.getLogger(BaseCommand.class);
public static final String 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;
static final int STATUS_NOT_ADMIN = PRIVATE_STATUS | 3;
@Option(name = "--help", usage = "display this help text", aliases = {"-h"})
private boolean help;
@SuppressWarnings("unused")
@Option(name = "--", usage = "end of options", handler = EndOfOptionsHandler.class)
private boolean endOfOptions;
protected InputStream in;
protected OutputStream out;
protected OutputStream err;
private ExitCallback exit;
@Inject
private CmdLineParser.Factory cmdLineParserFactory;
@Inject
private RequestCleanup cleanup;
@Inject
@CommandExecutor
private WorkQueue.Executor executor;
@Inject
private Provider<CurrentUser> userProvider;
@Inject
private Provider<SshScope.Context> contextProvider;
/** The task, as scheduled on a worker thread. */
private Future<?> task;
/** Text of the command line which lead up to invoking this instance. */
private String commandName = "";
/** Unparsed command line options. */
private String[] argv;
public void setInputStream(final InputStream in) {
this.in = in;
}
public void setOutputStream(final OutputStream out) {
this.out = out;
}
public void setErrorStream(final OutputStream err) {
this.err = err;
}
public void setExitCallback(final ExitCallback callback) {
this.exit = callback;
}
void setName(final String prefix) {
this.commandName = prefix;
}
public void setArguments(final String[] argv) {
this.argv = argv;
}
@Override
public void destroy() {
if (task != null && !task.isDone()) {
task.cancel(true);
}
}
/**
* Pass all state into the command, then run its start method.
* <p>
* 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(final Command cmd) {
cmd.setInputStream(in);
cmd.setOutputStream(out);
cmd.setErrorStream(err);
cmd.setExitCallback(exit);
}
/**
* Parses the command line argument, injecting parsed values into fields.
* <p>
* This method must be explicitly invoked to cause a parse.
*
* @throws UnloggedFailure if the command line arguments were invalid.
* @see Option
* @see Argument
*/
protected void parseCommandLine() throws UnloggedFailure {
final CmdLineParser clp = newCmdLineParser();
try {
clp.parseArgument(argv);
} catch (IllegalArgumentException err) {
if (!help) {
throw new UnloggedFailure(1, "fatal: " + err.getMessage());
}
} catch (CmdLineException err) {
if (!help) {
throw new UnloggedFailure(1, "fatal: " + err.getMessage());
}
}
if (help) {
final StringWriter msg = new StringWriter();
msg.write(commandName);
clp.printSingleLineUsage(msg, null);
msg.write('\n');
msg.write('\n');
clp.printUsage(msg, null);
msg.write('\n');
msg.write(usage());
throw new UnloggedFailure(1, msg.toString());
}
}
protected String usage() {
return "";
}
/** Construct a new parser for this command's received command line. */
protected CmdLineParser newCmdLineParser() {
return cmdLineParserFactory.create(this);
}
/**
* Spawn a function into its own thread.
* <p>
* Typically this should be invoked within {@link Command#start(Environment)},
* such as:
*
* <pre>
* startThread(new Runnable() {
* public void run() {
* runImp();
* }
* });
* </pre>
*
* @param thunk the runnable to execute on the thread, performing the
* command's logic.
*/
protected void startThread(final Runnable thunk) {
startThread(new CommandRunnable() {
@Override
public void run() throws Exception {
thunk.run();
}
});
}
/**
* Spawn a function into its own thread.
* <p>
* Typically this should be invoked within {@link Command#start(Environment)},
* such as:
*
* <pre>
* startThread(new CommandRunnable() {
* public void run() throws Exception {
* runImp();
* }
* });
* </pre>
* <p>
* 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.
*/
protected synchronized void startThread(final CommandRunnable thunk) {
final TaskThunk tt = new TaskThunk(thunk);
if (isAdminCommand()||(isAdminHighPriorityCommand() && userProvider.get().isAdministrator())) {
// 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 = executor.submit(tt);
}
}
private final boolean isAdminCommand() {
return getClass().getAnnotation(AdminCommand.class) != null;
}
private final boolean isAdminHighPriorityCommand() {
return getClass().getAnnotation(AdminHighPriorityCommand.class) != null;
}
/**
* Terminate this command and return a result code to the remote client.
* <p>
* 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(final int rc) {
exit.onExit(rc);
cleanup.run();
}
/** Wrap the supplied output stream in a UTF-8 encoded PrintWriter. */
protected static PrintWriter toPrintWriter(final OutputStream o) {
try {
return new PrintWriter(new BufferedWriter(new OutputStreamWriter(o, ENC)));
} catch (UnsupportedEncodingException e) {
// Our default encoding is required by the specifications for the
// runtime APIs, this should never, ever happen.
//
throw new RuntimeException("JVM lacks " + ENC + " encoding", e);
}
}
private int handleError(final Throwable e) {
if (e.getClass() == IOException.class
&& "Pipe closed".equals(e.getMessage())) {
// 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.getClass() == SshException.class
&& "Already closed".equals(e.getMessage())) {
// 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) {
} else {
final StringBuilder m = new StringBuilder();
m.append("Internal server error");
if (userProvider.get() instanceof IdentifiedUser) {
final IdentifiedUser u = (IdentifiedUser) userProvider.get();
m.append(" (user ");
m.append(u.getUserName());
m.append(")");
}
m.append(" during ");
m.append(contextProvider.get().getCommandLine());
log.error(m.toString(), e);
}
if (e instanceof Failure) {
final Failure f = (Failure) e;
try {
err.write((f.getMessage() + "\n").getBytes(ENC));
err.flush();
} catch (IOException e2) {
} catch (Throwable e2) {
log.warn("Cannot send failure message to client", e2);
}
return f.exitCode;
} else {
try {
err.write("fatal: internal server error\n".getBytes(ENC));
err.flush();
} catch (IOException e2) {
} catch (Throwable e2) {
log.warn("Cannot send internal server error message to client", e2);
}
return 128;
}
}
protected UnloggedFailure die(String msg) {
return new UnloggedFailure(1, "fatal: " + msg);
}
private final class TaskThunk implements CancelableRunnable, ProjectRunnable {
private final CommandRunnable thunk;
private final Context context;
private final String taskName;
private String projectName;
private TaskThunk(final CommandRunnable thunk) {
this.thunk = thunk;
this.context = contextProvider.get();
StringBuilder m = new StringBuilder();
m.append(context.getCommandLine());
if (userProvider.get() instanceof IdentifiedUser) {
IdentifiedUser u = (IdentifiedUser) userProvider.get();
m.append(" (" + u.getUserName() + ")");
}
this.taskName = m.toString();
}
@Override
public void cancel() {
final Context old = SshScope.set(context);
try {
onExit(STATUS_CANCEL);
} finally {
SshScope.set(old);
}
}
@Override
public void run() {
final Thread thisThread = Thread.currentThread();
final String thisName = thisThread.getName();
int rc = 0;
final Context old = SshScope.set(context);
try {
context.started = System.currentTimeMillis();
thisThread.setName("SSH " + taskName);
if (thunk instanceof ProjectCommandRunnable) {
((ProjectCommandRunnable) thunk).executeParseCommand();
projectName = ((ProjectCommandRunnable) thunk).getProjectName();
}
try {
thunk.run();
} catch (NoSuchProjectException e) {
throw new UnloggedFailure(1, e.getMessage() + " no such project");
}
out.flush();
err.flush();
} catch (Throwable e) {
try {
out.flush();
} catch (Throwable e2) {
}
try {
err.flush();
} catch (Throwable e2) {
}
rc = handleError(e);
} finally {
try {
onExit(rc);
} finally {
SshScope.set(old);
thisThread.setName(thisName);
}
}
}
@Override
public String toString() {
return taskName;
}
@Override
public String getProjectNameKey() {
return projectName;
}
@Override
public String getRemoteName() {
return null;
}
@Override
public boolean hasCustomizedPrint() {
return false;
}
}
/** Runnable function which can throw an exception. */
public static interface CommandRunnable {
public void run() throws Exception;
}
/** Runnable function which can retrieve a project name related to the task */
public static interface ProjectCommandRunnable extends CommandRunnable {
// execute parser command before running, in order to be able to retrieve
// project name
public void executeParseCommand() throws Exception;
public String 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(final int exitCode, final 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(final int exitCode, final String msg, final 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 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(final int exitCode, final 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(final int exitCode, final String msg,
final Throwable why) {
super(exitCode, msg, why);
}
}
}