Source for gnu.classpath.jdwp.Jdwp

   1: /* Jdwp.java -- Virtual machine to JDWP back-end programming interface
   2:    Copyright (C) 2005, 2006 Free Software Foundation
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: terms of your choice, provided that you also meet, for each linked
  32: independent module, the terms and conditions of the license of that
  33: module.  An independent module is a module which is not derived from
  34: or based on this library.  If you modify this library, you may extend
  35: this exception to your version of the library, but you are not
  36: obligated to do so.  If you do not wish to do so, delete this
  37: exception statement from your version. */
  38: 
  39: 
  40: package gnu.classpath.jdwp;
  41: 
  42: import gnu.classpath.jdwp.event.Event;
  43: import gnu.classpath.jdwp.event.EventManager;
  44: import gnu.classpath.jdwp.event.EventRequest;
  45: import gnu.classpath.jdwp.exception.JdwpException;
  46: import gnu.classpath.jdwp.processor.PacketProcessor;
  47: import gnu.classpath.jdwp.transport.ITransport;
  48: import gnu.classpath.jdwp.transport.JdwpConnection;
  49: import gnu.classpath.jdwp.transport.TransportException;
  50: import gnu.classpath.jdwp.transport.TransportFactory;
  51: 
  52: import java.io.IOException;
  53: import java.security.AccessController;
  54: import java.util.HashMap;
  55: 
  56: /**
  57:  * Main interface from the virtual machine to the JDWP back-end.
  58:  *
  59:  * The thread created by this class is only used for initialization.
  60:  * Once it exits, the JDWP backend is fully initialized.
  61:  *
  62:  * @author Keith Seitz (keiths@redhat.com)
  63:  */
  64: public class Jdwp
  65:   extends Thread
  66: {
  67:   // The single instance of the back-end
  68:   private static Jdwp _instance = null;
  69: 
  70:   /**
  71:    * Are we debugging? Only true if debugging
  72:    * *and* initialized.
  73:    */
  74:   public static boolean isDebugging = false;
  75: 
  76:   // Packet processor
  77:   private PacketProcessor _packetProcessor;
  78:   private Thread _ppThread;
  79: 
  80:   // JDWP configuration properties
  81:   private HashMap _properties;
  82: 
  83:   // The suspend property of the configure string
  84:   // (-Xrunjdwp:..suspend=<boolean>)
  85:   private static final String _PROPERTY_SUSPEND = "suspend";
  86: 
  87:   // Connection to debugger
  88:   private JdwpConnection _connection;
  89: 
  90:   // Are we shutting down the current session?
  91:   private boolean _shutdown;
  92: 
  93:   // A thread group for the JDWP threads
  94:   private ThreadGroup _group;
  95: 
  96:   // Initialization synchronization
  97:   private Object _initLock = new Object ();
  98:   private int _initCount = 0;
  99: 
 100:   /**
 101:    * constructor
 102:    */
 103:   public Jdwp ()
 104:   {
 105:     _shutdown = false;
 106:     _instance = this;
 107:   }
 108: 
 109:   /**
 110:    * Returns the JDWP back-end, creating an instance of it
 111:    * if one does not already exist.
 112:    */
 113:   public static Jdwp getDefault ()
 114:   {
 115:     return _instance;
 116:   }
 117: 
 118:   /**
 119:    * Get the thread group used by JDWP threads
 120:    * 
 121:    * @return the thread group
 122:    */
 123:   public ThreadGroup getJdwpThreadGroup()
 124:   {
 125:     return _group;
 126:   }
 127:   
 128:   /**
 129:    * Should the virtual machine suspend on startup?
 130:    */
 131:   public static boolean suspendOnStartup ()
 132:   {
 133:     Jdwp jdwp = getDefault ();
 134:     if (jdwp != null)
 135:       {
 136:     String suspend = (String) jdwp._properties.get (_PROPERTY_SUSPEND);
 137:     if (suspend != null && suspend.equals ("y"))
 138:       return true;
 139:       }
 140: 
 141:     return false;
 142:   }
 143: 
 144:   /**
 145:    * Configures the back-end
 146:    *
 147:    * @param configArgs  a string of configury options
 148:    */
 149:   public void configure (String configArgs)
 150:   {
 151:     _processConfigury (configArgs);
 152:   }
 153: 
 154:   // A helper function to initialize the transport layer
 155:   private void _doInitialization ()
 156:     throws TransportException
 157:   {
 158:     _group = new ThreadGroup ("JDWP threads");
 159:     // initialize transport
 160:     ITransport transport = TransportFactory.newInstance (_properties);
 161:     _connection = new JdwpConnection (_group, transport);
 162:     _connection.initialize ();
 163:     _connection.start ();
 164: 
 165:     // Create processor
 166:     _packetProcessor = new PacketProcessor (_connection);
 167:     _ppThread = new Thread (_group, new Runnable ()
 168:       {
 169:     public void run ()
 170:     {
 171:       AccessController.doPrivileged (_packetProcessor);
 172:     }
 173:       }, "packet processor");
 174:     _ppThread.start ();
 175:   }
 176: 
 177:   /**
 178:    * Shutdown the JDWP back-end
 179:    *
 180:    * NOTE: This does not quite work properly. See notes in 
 181:    * run() on this subject (catch of InterruptedException).
 182:    */
 183:   public void shutdown ()
 184:   {
 185:     if (!_shutdown)
 186:       {
 187:     _packetProcessor.shutdown ();
 188:     _ppThread.interrupt ();
 189:     _connection.shutdown ();
 190:     _shutdown = true;
 191:     isDebugging = false;
 192: 
 193:     /* FIXME: probably need to check state of user's
 194:        program -- if it is suspended, we need to either
 195:        resume or kill them. */
 196: 
 197:     interrupt ();
 198:       }
 199:   }
 200: 
 201:   /**
 202:    * Notify the debugger of an event. This method should not
 203:    * be called if debugging is not active (but it would not
 204:    * cause any harm). Places where event notifications occur
 205:    * should check isDebugging before doing anything.
 206:    *
 207:    * The event is filtered through the event manager before being
 208:    * sent.
 209:    *
 210:    * FIXME: Probably need logic to send multiple events
 211:    * @param event the event to report
 212:    */
 213:   public static void notify (Event event)
 214:   {
 215:     Jdwp jdwp = getDefault ();
 216:     if (jdwp != null)
 217:       {
 218:     EventManager em = EventManager.getDefault ();
 219:     EventRequest request = em.getEventRequest (event);
 220:     if (request != null)
 221:       {
 222:         try
 223:           {
 224:         System.out.println ("Jdwp.notify: sending event " + event);
 225:         sendEvent (request, event);
 226:         jdwp._enforceSuspendPolicy (request.getSuspendPolicy ());
 227:           }
 228:         catch (Exception e)
 229:           {
 230:         /* Really not much we can do. For now, just print out
 231:            a warning to the user. */
 232:         System.out.println ("Jdwp.notify: caught exception: " + e);
 233:           }
 234:       }
 235:       }
 236:   }
 237:   
 238:   /**
 239:    * Sends the event to the debugger.
 240:    *
 241:    * This method bypasses the event manager's filtering.
 242:    *
 243:    * @param  request  the debugger request for the event
 244:    * @param  event    the event to send
 245:    * @throws IOException if a communications failure occurs
 246:    */
 247:   public static void sendEvent (EventRequest request, Event event)
 248:       throws IOException
 249:   {
 250:     Jdwp jdwp = getDefault ();
 251:     if (jdwp != null)
 252:       {
 253:     // !! May need to implement send queue?
 254:     synchronized (jdwp._connection)
 255:       {
 256:         jdwp._connection.sendEvent (request, event);
 257:       }
 258:       }
 259:   }
 260: 
 261:   // Helper function to enforce suspend policies on event notification
 262:   private void _enforceSuspendPolicy (byte suspendPolicy)
 263:     throws JdwpException
 264:   {
 265:     switch (suspendPolicy)
 266:       {
 267:       case EventRequest.SUSPEND_NONE:
 268:     // do nothing
 269:     break;
 270: 
 271:       case EventRequest.SUSPEND_THREAD:
 272:     VMVirtualMachine.suspendThread (Thread.currentThread ());
 273:     break;
 274: 
 275:       case EventRequest.SUSPEND_ALL:
 276:     VMVirtualMachine.suspendAllThreads ();
 277:     break;
 278:       }
 279:   }
 280: 
 281:   /**
 282:    * Allows subcomponents to specify that they are
 283:    * initialized.
 284:    *
 285:    * Subcomponents include JdwpConnection and PacketProcessor.
 286:    */
 287:   public void subcomponentInitialized ()
 288:   {
 289:     synchronized (_initLock)
 290:       {
 291:     ++_initCount;
 292:     _initLock.notify ();
 293:       }
 294:   }
 295: 
 296:   public void run ()
 297:   {
 298:     try
 299:       {
 300:     _doInitialization ();
 301: 
 302:     /* We need a little internal synchronization here, so that
 303:        when this thread dies, the back-end will be fully initialized,
 304:        ready to start servicing the VM and debugger. */
 305:     synchronized (_initLock)
 306:       {
 307:         while (_initCount != 2)
 308:           _initLock.wait ();
 309:       }
 310:     _initLock = null;
 311:       }
 312:     catch (Throwable t)
 313:       {
 314:     System.out.println ("Exception in JDWP back-end: " + t);
 315:     System.exit (1);
 316:       }
 317: 
 318:     /* Force creation of the EventManager. If the event manager
 319:        has not been created when isDebugging is set, it is possible
 320:        that the VM will call Jdwp.notify (which uses EventManager)
 321:        while the EventManager is being created (or at least this is
 322:        a problem with gcj/gij). */
 323:     EventManager.getDefault();
 324: 
 325:     // Now we are finally ready and initialized
 326:     isDebugging = true;
 327:   }
 328: 
 329:   // A helper function to process the configure string "-Xrunjdwp:..."
 330:   private void _processConfigury (String configString)
 331:   {
 332:     // Loop through configuration arguments looking for a
 333:     // transport name
 334:     _properties = new HashMap ();
 335:     String[] options = configString.split (",");
 336:     for (int i = 0; i < options.length; ++i)
 337:       {
 338:     String[] property = options[i].split ("=");
 339:     if (property.length == 2)
 340:       _properties.put (property[0], property[1]);
 341:     // ignore malformed options
 342:       }
 343:   }
 344: }