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

   1 /**********************************************************************
   2  * Copyright (c) 2012, 2013 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 final static String DONE_MARKUP_STRING = "--RSE:donedonedone:--"; //$NON-NLS-1$
  53
  54     /** Sub-string to be echoed when running a command in shell. */
  55     public final static String BEGIN_END_TAG = "BEGIN-END-TAG:"; //$NON-NLS-1$
  56
  57     /** Command delimiter for shell */
  58     public final static String CMD_DELIMITER = "\n"; //$NON-NLS-1$
  59
  60     /** Shell "echo" command */
  61     public final static String SHELL_ECHO_CMD = " echo "; //$NON-NLS-1$
  62
  63     /** Default command separator */
  64     public final static 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      * (non-Javadoc)
  97      * @see org.eclipse.linuxtools.internal.lttng2.ui.views.control.service.ICommandShell#connect()
  98      */
  99     @Override
 100     public void connect() throws ExecutionException {
 101         IShellService shellService = fProxy.getShellService();
 102         Process p = null;
 103         try {
 104             fHostShell = shellService.launchShell("", new String[0], new NullProgressMonitor()); //$NON-NLS-1$
 105             p = new HostShellProcessAdapter(fHostShell);
 106         } catch (Exception e) {
 107             throw new ExecutionException(Messages.TraceControl_CommandShellError, e);
 108         }
 109         fInputBufferReader = new BufferedReader(new InputStreamReader(p.getInputStream()));
 110         fErrorBufferReader = new BufferedReader(new InputStreamReader(p.getErrorStream()));
 111         fIsConnected = true;
 112     }
 113
 114     /*
 115      * (non-Javadoc)
 116      * @see org.eclipse.linuxtools.internal.lttng2.ui.views.control.service.ICommandShell#disconnect()
 117      */
 118     @Override
 119     public void disconnect() {
 120         fIsConnected = false;
 121         try {
 122             fInputBufferReader.close();
 123             fErrorBufferReader.close();
 124         } catch (IOException e) {
 125             // ignore
 126         }
 127     }
 128
 129     /*
 130      * (non-Javadoc)
 131      * @see org.eclipse.linuxtools.internal.lttng2.ui.views.control.service.ICommandShell#executeCommand(java.lang.String, org.eclipse.core.runtime.IProgressMonitor)
 132      */
 133     @Override
 134     public ICommandResult executeCommand(String command, IProgressMonitor monitor) throws ExecutionException {
 135         return executeCommand(command, monitor, true);
 136     }
 137
 138     /*
 139      * (non-Javadoc)
 140      * @see org.eclipse.linuxtools.internal.lttng2.ui.views.control.service.ICommandShell#executeCommand(java.lang.String, org.eclipse.core.runtime.IProgressMonitor, boolean)
 141      */
 142     @Override
 143     public ICommandResult executeCommand(final String command, final IProgressMonitor monitor, final boolean checkReturnValue) throws ExecutionException {
 144         if (fIsConnected) {
 145             FutureTask<CommandResult> future = new FutureTask<CommandResult>(new Callable<CommandResult>() {
 146                 @Override
 147                 public CommandResult call() throws IOException, CancellationException {
 148                     final ArrayList<String> result = new ArrayList<String>();
 149
 150                     synchronized (fHostShell) {
 151                         // Initialize return value which will be updated in isAliasEchoResult()
 152                         fReturnValue = 0;
 153
 154                         int startAlias = fRandom.nextInt();
 155                         int endAlias = fRandom.nextInt();
 156                         fHostShell.writeToShell(formatShellCommand(command, startAlias, endAlias));
 157
 158                         String nextLine;
 159                         boolean isStartFound = false;
 160                         while ((nextLine = fInputBufferReader.readLine()) != null) {
 161
 162                             if (monitor.isCanceled()) {
 163                                 flushInput();
 164                                 throw new CancellationException();
 165                             }
 166
 167                             // check if line contains echoed start alias
 168                             if (isAliasEchoResult(nextLine, startAlias, true)) {
 169                                 isStartFound = true;
 170                                 continue;
 171                             }
 172
 173                             // check if line contains is the end mark-up. This will retrieve also
 174                             // the return value of the actual command.
 175                             if (isAliasEchoResult(nextLine, endAlias, false)) {
 176                                 break;
 177                             }
 178
 179                             // Ignore line if
 180                             // 1) start hasn't been found or
 181                             // 2) line is an echo of the command or
 182                             // 3) line is  an echo of the end mark-up
 183                             if (!isStartFound ||
 184                                     isCommandEcho(nextLine, command) ||
 185                                     nextLine.contains(getEchoResult(endAlias)))
 186                             {
 187                                 continue;
 188                             }
 189
 190                             // Now it's time add to the result
 191                             result.add(nextLine);
 192                         }
 193
 194                         // Read any left over output
 195                         flushInput();
 196
 197                         // Read error stream output when command failed.
 198                         if (fReturnValue != 0) {
 199                             while(fErrorBufferReader.ready()) {
 200                                 if ((nextLine = fErrorBufferReader.readLine()) != null)  {
 201                                     result.add(nextLine);
 202                                 }
 203                             }
 204                         }
 205                     }
 206                     return new CommandResult(fReturnValue, result.toArray(new String[result.size()]));
 207                 }
 208             });
 209
 210             fExecutor.execute(future);
 211
 212             try {
 213                 return future.get(ControlPreferences.getInstance().getCommandTimeout(), TimeUnit.SECONDS);
 214             } catch (java.util.concurrent.ExecutionException ex) {
 215                 throw new ExecutionException(Messages.TraceControl_ExecutionFailure, ex);
 216             } catch (InterruptedException ex) {
 217                 throw new ExecutionException(Messages.TraceControl_ExecutionCancelled, ex);
 218             } catch (TimeoutException ex) {
 219                 throw new ExecutionException(Messages.TraceControl_ExecutionTimeout, ex);
 220             }
 221         }
 222         throw new ExecutionException(Messages.TraceControl_ShellNotConnected, null);
 223     }
 224
 225     // ------------------------------------------------------------------------
 226     // Helper methods
 227     // ------------------------------------------------------------------------
 228     /**
 229      * Flushes the buffer reader
 230      * @throws IOException
 231      */
 232     private void flushInput() throws IOException {
 233         char[] cbuf = new char[1];
 234         while (fInputBufferReader.ready()) {
 235             if (fInputBufferReader.read(cbuf, 0, 1) == -1) {
 236                 break;
 237             }
 238         }
 239     }
 240
 241     /**
 242      * Format the command to be sent into the shell command with start and end marker strings.
 243      * The start marker is need to know when the actual command output starts. The end marker
 244      * string is needed so we can tell that end of output has been reached.
 245      *
 246      * @param cmd The actual command
 247      * @param startAlias The command alias for start marker
 248      * @param endAlias The command alias for end marker
 249      * @return formatted command string
 250      */
 251     private static String formatShellCommand(String cmd, int startAlias, int endAlias) {
 252         if (cmd == null || cmd.equals("")) { //$NON-NLS-1$
 253             return cmd;
 254         }
 255         StringBuffer formattedCommand = new StringBuffer();
 256         // Make multi-line command.
 257         // Wrap actual command with start marker and end marker to wrap actual command.
 258         formattedCommand.append(getEchoCmd(startAlias));
 259         formattedCommand.append(CMD_DELIMITER);
 260         formattedCommand.append(cmd);
 261         formattedCommand.append(CMD_DELIMITER);
 262         formattedCommand.append(getEchoCmd(endAlias));
 263         formattedCommand.append(CMD_DELIMITER);
 264         return formattedCommand.toString();
 265     }
 266
 267     /**
 268      * Creates a echo command line in the format: echo <start tag> <alias> <end tag> $?
 269      *
 270      * @param alias The command alias integer to be included in the echoed message.
 271      * @return the echo command line
 272      */
 273     private static String getEchoCmd(int alias) {
 274         return SHELL_ECHO_CMD + getEchoResult(alias) + "$?"; //$NON-NLS-1$
 275     }
 276
 277     /**
 278      * Creates the expected result for a given command alias:
 279      * <start tag> <alias> <end tag> $?
 280      *
 281      * @param alias The command alias integer to be included in the echoed message.
 282      * @return the expected echo result
 283      */
 284     private static String getEchoResult(int alias) {
 285         return BEGIN_END_TAG + String.valueOf(alias) + DONE_MARKUP_STRING;
 286     }
 287
 288     /**
 289      * Verifies if given command line contains a command alias echo result.
 290      *
 291      * @param line The output line to test.
 292      * @param alias The command alias
 293      * @param checkReturnValue <code>true</code> to retrieve command result (previous command) <code>false</code>
 294      * @return <code>true</code> if output line is a command alias echo result else <code>false</code>
 295      */
 296     private boolean isAliasEchoResult(String line, int alias, boolean checkReturnValue) {
 297         String expected = getEchoResult(alias);
 298         if (line.startsWith(expected)) {
 299             if (!checkReturnValue) {
 300                 try {
 301                     int k = Integer.valueOf(line.substring(expected.length()));
 302                     fReturnValue = k;
 303                 } catch (NumberFormatException e) {
 304                     // do nothing
 305                 }
 306             }
 307             return true;
 308         }
 309         int index = line.indexOf(expected);
 310         if (index > 0) {
 311             if (line.indexOf(SHELL_ECHO_CMD) == -1) {
 312                 return true;
 313             }
 314         }
 315
 316         return false;
 317     }
 318
 319     /**
 320      * Verifies if output line is an echo of the given command line. If the
 321      * output line is longer then the maximum line lengths (e.g. for ssh), the
 322      * shell adds a line break character. This method takes this in
 323      * consideration by comparing the command line without any whitespaces.
 324      *
 325      * @param line
 326      *            The output line to verify
 327      * @param cmd
 328      *            The command executed
 329      * @return <code>true</code> if it's an echoed command line else
 330      *         <code>false</code>
 331      */
 332     @SuppressWarnings("nls")
 333     private static boolean isCommandEcho(String line, String cmd) {
 334         String s1 = line.replaceAll("\\s","");
 335         String s2 = cmd.replaceAll("\\s","");
 336         s2 = s2.replaceAll("(\\*)", "(\\\\*)");
 337         String patternStr = ".*(" + s2 +")$";
 338         return s1.matches(patternStr);
 339     }
 340 }