org.eclipse.linuxtools.lttng2.ui/src/org/eclipse/linuxtools/internal/lttng2/ui/views/control/remote/CommandShell.java

   1 /**********************************************************************
   2  * Copyright (c) 2012, 2014 Ericsson
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   Patrick Tasse - Initial API and implementation
  11  *   Bernd Hufmann - Updated using Executor Framework
  12  **********************************************************************/
  13 package org.eclipse.linuxtools.internal.lttng2.ui.views.control.remote;
  14
  15 import java.io.BufferedReader;
  16 import java.io.IOException;
  17 import java.io.InputStreamReader;
  18 import java.util.ArrayList;
  19 import java.util.Random;
  20 import java.util.concurrent.Callable;
  21 import java.util.concurrent.CancellationException;
  22 import java.util.concurrent.ExecutorService;
  23 import java.util.concurrent.Executors;
  24 import java.util.concurrent.FutureTask;
  25 import java.util.concurrent.TimeUnit;
  26 import java.util.concurrent.TimeoutException;
  27
  28 import org.eclipse.core.commands.ExecutionException;
  29 import org.eclipse.core.runtime.IProgressMonitor;
  30 import org.eclipse.core.runtime.NullProgressMonitor;
  31 import org.eclipse.linuxtools.internal.lttng2.ui.views.control.messages.Messages;
  32 import org.eclipse.linuxtools.internal.lttng2.ui.views.control.preferences.ControlPreferences;
  33 import org.eclipse.rse.services.shells.HostShellProcessAdapter;
  34 import org.eclipse.rse.services.shells.IHostShell;
  35 import org.eclipse.rse.services.shells.IShellService;
  36
  37 /**
  38  * <p>
  39  * Implementation of remote command execution using RSE's shell service.
  40  * </p>
  41  *
  42  * @author Patrick Tasse
  43  * @author Bernd Hufmann
  44  */
  45 public class CommandShell implements ICommandShell {
  46
  47     // ------------------------------------------------------------------------
  48     // Constants
  49     // ------------------------------------------------------------------------
  50
  51     /** Sub-string to be echo'ed when running command in shell, used to indicate that the command has finished running */
  52     public static final String DONE_MARKUP_STRING = "--RSE:donedonedone:--"; //$NON-NLS-1$
  53
  54     /** Sub-string to be echoed when running a command in shell. */
  55     public static final String BEGIN_END_TAG = "BEGIN-END-TAG:"; //$NON-NLS-1$
  56
  57     /** Command delimiter for shell */
  58     public static final String CMD_DELIMITER = "\n"; //$NON-NLS-1$
  59
  60     /** Shell "echo" command */
  61     public static final String SHELL_ECHO_CMD = " echo "; //$NON-NLS-1$
  62
  63     /** Default command separator */
  64     public static final char CMD_SEPARATOR = ';';
  65
  66     // ------------------------------------------------------------------------
  67     // Attributes
  68     // ------------------------------------------------------------------------
  69     private IRemoteSystemProxy fProxy = null;
  70     private IHostShell fHostShell = null;
  71     private BufferedReader fInputBufferReader = null;
  72     private BufferedReader fErrorBufferReader = null;
  73     private final ExecutorService fExecutor = Executors.newFixedThreadPool(1);
  74     private boolean fIsConnected = false;
  75     private final Random fRandom = new Random(System.currentTimeMillis());
  76     private int fReturnValue;
  77
  78     // ------------------------------------------------------------------------
  79     // Constructors
  80     // ------------------------------------------------------------------------
  81
  82     /**
  83      * Create a new command shell
  84      *
  85      * @param proxy
  86      *            The RSE proxy for this shell
  87      */
  88     public CommandShell(IRemoteSystemProxy proxy) {
  89         fProxy = proxy;
  90     }
  91
  92     // ------------------------------------------------------------------------
  93     // Operations
  94     // ------------------------------------------------------------------------
  95
  96     @Override
  97     public void connect() throws ExecutionException {
  98         IShellService shellService = fProxy.getShellService();
  99         Process p = null;
 100         try {
 101             fHostShell = shellService.launchShell("", new String[0], new NullProgressMonitor()); //$NON-NLS-1$
 102             p = new HostShellProcessAdapter(fHostShell);
 103         } catch (Exception e) {
 104             throw new ExecutionException(Messages.TraceControl_CommandShellError, e);
 105         }
 106         fInputBufferReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
 107         fErrorBufferReader = new BufferedReader(new InputStreamReader(p.getErrorStream()));
 108         fIsConnected = true;
 109     }
 110
 111     @Override
 112     public void disconnect() {
 113         fIsConnected = false;
 114         try {
 115             fInputBufferReader.close();
 116             fErrorBufferReader.close();
 117         } catch (IOException e) {
 118             // ignore
 119         }
 120     }
 121
 122     @Override
 123     public ICommandResult executeCommand(String command, IProgressMonitor monitor) throws ExecutionException {
 124         return executeCommand(command, monitor, true);
 125     }
 126
 127     @Override
 128     public ICommandResult executeCommand(final String command, final IProgressMonitor monitor, final boolean checkReturnValue) throws ExecutionException {
 129         if (fIsConnected) {
 130             FutureTask<CommandResult> future = new FutureTask<>(new Callable<CommandResult>() {
 131                 @Override
 132                 public CommandResult call() throws IOException, CancellationException {
 133                     final ArrayList<String> result = new ArrayList<>();
 134
 135                     synchronized (fHostShell) {
 136                         // Initialize return value which will be updated in isAliasEchoResult()
 137                         fReturnValue = 0;
 138
 139                         int startAlias = fRandom.nextInt();
 140                         int endAlias = fRandom.nextInt();
 141                         fHostShell.writeToShell(formatShellCommand(command, startAlias, endAlias));
 142
 143                         String nextLine;
 144                         boolean isStartFound = false;
 145                         while ((nextLine = fInputBufferReader.readLine()) != null) {
 146
 147                             if (monitor.isCanceled()) {
 148                                 flushInput();
 149                                 throw new CancellationException();
 150                             }
 151
 152                             // check if line contains echoed start alias
 153                             if (isAliasEchoResult(nextLine, startAlias, true)) {
 154                                 isStartFound = true;
 155                                 continue;
 156                             }
 157
 158                             // check if line contains is the end mark-up. This will retrieve also
 159                             // the return value of the actual command.
 160                             if (isAliasEchoResult(nextLine, endAlias, false)) {
 161                                 break;
 162                             }
 163
 164                             // Ignore line if
 165                             // 1) start hasn't been found or
 166                             // 2) line is an echo of the command or
 167                             // 3) line is  an echo of the end mark-up
 168                             if (!isStartFound ||
 169                                     isCommandEcho(nextLine, command) ||
 170                                     nextLine.contains(getEchoResult(endAlias)))
 171                             {
 172                                 continue;
 173                             }
 174
 175                             // Now it's time add to the result
 176                             result.add(nextLine);
 177                         }
 178
 179                         // Read any left over output
 180                         flushInput();
 181
 182                         // Read error stream output when command failed.
 183                         if (fReturnValue != 0) {
 184                             while(fErrorBufferReader.ready()) {
 185                                 if ((nextLine = fErrorBufferReader.readLine()) != null)  {
 186                                     result.add(nextLine);
 187                                 }
 188                             }
 189                         }
 190                     }
 191                     return new CommandResult(fReturnValue, result.toArray(new String[result.size()]));
 192                 }
 193             });
 194
 195             fExecutor.execute(future);
 196
 197             try {
 198                 return future.get(ControlPreferences.getInstance().getCommandTimeout(), TimeUnit.SECONDS);
 199             } catch (java.util.concurrent.ExecutionException ex) {
 200                 throw new ExecutionException(Messages.TraceControl_ExecutionFailure, ex);
 201             } catch (InterruptedException ex) {
 202                 throw new ExecutionException(Messages.TraceControl_ExecutionCancelled, ex);
 203             } catch (TimeoutException ex) {
 204                 throw new ExecutionException(Messages.TraceControl_ExecutionTimeout, ex);
 205             }
 206         }
 207         throw new ExecutionException(Messages.TraceControl_ShellNotConnected, null);
 208     }
 209
 210     // ------------------------------------------------------------------------
 211     // Helper methods
 212     // ------------------------------------------------------------------------
 213     /**
 214      * Flushes the buffer reader
 215      * @throws IOException
 216      */
 217     private void flushInput() throws IOException {
 218         char[] cbuf = new char[1];
 219         while (fInputBufferReader.ready()) {
 220             if (fInputBufferReader.read(cbuf, 0, 1) == -1) {
 221                 break;
 222             }
 223         }
 224     }
 225
 226     /**
 227      * Format the command to be sent into the shell command with start and end marker strings.
 228      * The start marker is need to know when the actual command output starts. The end marker
 229      * string is needed so we can tell that end of output has been reached.
 230      *
 231      * @param cmd The actual command
 232      * @param startAlias The command alias for start marker
 233      * @param endAlias The command alias for end marker
 234      * @return formatted command string
 235      */
 236     private static String formatShellCommand(String cmd, int startAlias, int endAlias) {
 237         if (cmd == null || cmd.equals("")) { //$NON-NLS-1$
 238             return cmd;
 239         }
 240         StringBuffer formattedCommand = new StringBuffer();
 241         // Make multi-line command.
 242         // Wrap actual command with start marker and end marker to wrap actual command.
 243         formattedCommand.append(getEchoCmd(startAlias));
 244         formattedCommand.append(CMD_DELIMITER);
 245         formattedCommand.append(cmd);
 246         formattedCommand.append(CMD_DELIMITER);
 247         formattedCommand.append(getEchoCmd(endAlias));
 248         formattedCommand.append(CMD_DELIMITER);
 249         return formattedCommand.toString();
 250     }
 251
 252     /**
 253      * Creates a echo command line in the format: echo <start tag> <alias> <end tag> $?
 254      *
 255      * @param alias The command alias integer to be included in the echoed message.
 256      * @return the echo command line
 257      */
 258     private static String getEchoCmd(int alias) {
 259         return SHELL_ECHO_CMD + getEchoResult(alias) + "$?"; //$NON-NLS-1$
 260     }
 261
 262     /**
 263      * Creates the expected result for a given command alias:
 264      * <start tag> <alias> <end tag> $?
 265      *
 266      * @param alias The command alias integer to be included in the echoed message.
 267      * @return the expected echo result
 268      */
 269     private static String getEchoResult(int alias) {
 270         return BEGIN_END_TAG + String.valueOf(alias) + DONE_MARKUP_STRING;
 271     }
 272
 273     /**
 274      * Verifies if given command line contains a command alias echo result.
 275      *
 276      * @param line The output line to test.
 277      * @param alias The command alias
 278      * @param checkReturnValue <code>true</code> to retrieve command result (previous command) <code>false</code>
 279      * @return <code>true</code> if output line is a command alias echo result else <code>false</code>
 280      */
 281     private boolean isAliasEchoResult(String line, int alias, boolean checkReturnValue) {
 282         String expected = getEchoResult(alias);
 283         if (line.startsWith(expected)) {
 284             if (!checkReturnValue) {
 285                 try {
 286                     int k = Integer.valueOf(line.substring(expected.length()));
 287                     fReturnValue = k;
 288                 } catch (NumberFormatException e) {
 289                     // do nothing
 290                 }
 291             }
 292             return true;
 293         }
 294         int index = line.indexOf(expected);
 295         if ((index > 0) && (line.indexOf(SHELL_ECHO_CMD) == -1)) {
 296             return true;
 297         }
 298
 299         return false;
 300     }
 301
 302     /**
 303      * Verifies if output line is an echo of the given command line. If the
 304      * output line is longer then the maximum line lengths (e.g. for ssh), the
 305      * shell adds a line break character. This method takes this in
 306      * consideration by comparing the command line without any whitespaces.
 307      *
 308      * @param line
 309      *            The output line to verify
 310      * @param cmd
 311      *            The command executed
 312      * @return <code>true</code> if it's an echoed command line else
 313      *         <code>false</code>
 314      */
 315     @SuppressWarnings("nls")
 316     private static boolean isCommandEcho(String line, String cmd) {
 317         String s1 = line.replaceAll("\\s","");
 318         String s2 = cmd.replaceAll("\\s","");
 319         s2 = s2.replaceAll("(\\*)", "(\\\\*)");
 320         String patternStr = ".*(" + s2 +")$";
 321         return s1.matches(patternStr);
 322     }
 323 }