eventhelper.c

来自「This is a resource based on j2me embedde」· C语言 代码 · 共 1,130 行 · 第 1/3 页

    (void)outStream_writeObjectRef(env, out, evinfo->thread);
    (void)outStream_writeByte(out, classTag);
    (void)outStream_writeObjectRef(env, out, evinfo->clazz);
    (void)outStream_writeString(out, signature);
    (void)outStream_writeInt(out, map2jdwpClassStatus(status));
    jvmtiDeallocate(signature);
}

static void 
writeVMDeathEvent(JNIEnv *env, PacketOutputStream *out, EventInfo *evinfo)
{
}

static void 
handleEventCommandSingle(JNIEnv *env, PacketOutputStream *out, 
                           EventCommandSingle *command)
{
    EventInfo *evinfo = &command->info;

    (void)outStream_writeByte(out, eventIndex2jdwp(evinfo->ei));
    (void)outStream_writeInt(out, command->id);

    switch (evinfo->ei) {
        case EI_SINGLE_STEP:  
            writeSingleStepEvent(env, out, evinfo);
            break;
        case EI_BREAKPOINT:   
            writeBreakpointEvent(env, out, evinfo);
            break;
        case EI_FIELD_ACCESS:    
            writeFieldAccessEvent(env, out, evinfo);
            break;
        case EI_FIELD_MODIFICATION:    
            writeFieldModificationEvent(env, out, evinfo);
            break;
        case EI_EXCEPTION:    
            writeExceptionEvent(env, out, evinfo);
            break;
        case EI_THREAD_START:
        case EI_THREAD_END:   
            writeThreadEvent(env, out, evinfo);
            break;
        case EI_CLASS_LOAD:   
        case EI_CLASS_PREPARE:   
            writeClassEvent(env, out, evinfo);
            break;
        case EI_MONITOR_CONTENDED_ENTER:
        case EI_MONITOR_CONTENDED_ENTERED:
        case EI_MONITOR_WAIT:
        case EI_MONITOR_WAITED:
            writeMonitorEvent(env, out, evinfo);
            break;
        case EI_VM_DEATH:
            writeVMDeathEvent(env, out, evinfo);
            break;
        default:
            EXIT_ERROR(AGENT_ERROR_INVALID_EVENT_TYPE,"unknown event index");
            break;
    }
    tossEventInfoRefs(env, evinfo);
}

static void 
handleUnloadCommandSingle(JNIEnv* env, PacketOutputStream *out, 
                           UnloadCommandSingle *command) 
{
    (void)outStream_writeByte(out, JDWP_EVENT(CLASS_UNLOAD));
    (void)outStream_writeInt(out, command->id);
    (void)outStream_writeString(out, command->classSignature);
    jvmtiDeallocate(command->classSignature);
    command->classSignature = NULL;
}

static void 
handleFrameEventCommandSingle(JNIEnv* env, PacketOutputStream *out, 
                              FrameEventCommandSingle *command) 
{
    if (command->typeKey) {
        (void)outStream_writeByte(out, JDWP_EVENT(METHOD_EXIT_WITH_RETURN_VALUE));
    } else {
        (void)outStream_writeByte(out, eventIndex2jdwp(command->ei));
    }
    (void)outStream_writeInt(out, command->id);
    (void)outStream_writeObjectRef(env, out, command->thread);
    writeCodeLocation(out, command->clazz, command->method, command->location);
    if (command->typeKey) {
        (void)outStream_writeValue(env, out, command->typeKey, command->returnValue);
        if (isObjectTag(command->typeKey) &&
            command->returnValue.l != NULL) {
            tossGlobalRef(env, &(command->returnValue.l));
        }
    }
    tossGlobalRef(env, &(command->thread));
    tossGlobalRef(env, &(command->clazz));
}

static void
suspendWithInvokeEnabled(jbyte policy, jthread thread)
{
    invoker_enableInvokeRequests(thread);

    if (policy == JDWP_SUSPEND_POLICY(ALL)) {
        (void)threadControl_suspendAll();
    } else {
        (void)threadControl_suspendThread(thread, JNI_FALSE);
    }
}

static void
handleReportEventCompositeCommand(JNIEnv *env, 
                                  ReportEventCompositeCommand *recc) 
{
    PacketOutputStream out;
    jint count = recc->eventCount;
    jint i;

    if (recc->suspendPolicy != JDWP_SUSPEND_POLICY(NONE)) {
        /* must determine thread to interrupt before writing */
        /* since writing destroys it */
        jthread thread = NULL;
        for (i = 0; i < count; i++) {
            CommandSingle *single = &(recc->singleCommand[i]);
            switch (single->singleKind) {
                case COMMAND_SINGLE_EVENT:
                    thread = single->u.eventCommand.info.thread;
                    break;
                case COMMAND_SINGLE_FRAME_EVENT:
                    thread = single->u.frameEventCommand.thread;
                    break;
            }
            if (thread != NULL) {
                break;
            }
        }

        if (thread == NULL) { 
            (void)threadControl_suspendAll();
        } else {
            suspendWithInvokeEnabled(recc->suspendPolicy, thread);
        }
    }

    outStream_initCommand(&out, uniqueID(), 0x0,
                          JDWP_COMMAND_SET(Event), 
                          JDWP_COMMAND(Event, Composite));
    (void)outStream_writeByte(&out, recc->suspendPolicy);
    (void)outStream_writeInt(&out, count);

    for (i = 0; i < count; i++) {
        CommandSingle *single = &(recc->singleCommand[i]);
        switch (single->singleKind) {
            case COMMAND_SINGLE_EVENT:
                handleEventCommandSingle(env, &out, 
                                         &single->u.eventCommand);
                break;
            case COMMAND_SINGLE_UNLOAD:
                handleUnloadCommandSingle(env, &out, 
                                          &single->u.unloadCommand);
                break;
            case COMMAND_SINGLE_FRAME_EVENT:
                handleFrameEventCommandSingle(env, &out, 
                                              &single->u.frameEventCommand);
                break;
        }
    }

    outStream_sendCommand(&out);
    outStream_destroy(&out);
}

static void
handleReportInvokeDoneCommand(JNIEnv* env, ReportInvokeDoneCommand *command) 
{
    invoker_completeInvokeRequest(command->thread);
    tossGlobalRef(env, &(command->thread));
}

static void
handleReportVMInitCommand(JNIEnv* env, ReportVMInitCommand *command) 
{
    PacketOutputStream out;

    if (command->suspendPolicy == JDWP_SUSPEND_POLICY(ALL)) {
        (void)threadControl_suspendAll();
    } else if (command->suspendPolicy == JDWP_SUSPEND_POLICY(EVENT_THREAD)) {
        (void)threadControl_suspendThread(command->thread, JNI_FALSE);
    }

    outStream_initCommand(&out, uniqueID(), 0x0,
                          JDWP_COMMAND_SET(Event), 
                          JDWP_COMMAND(Event, Composite));
    (void)outStream_writeByte(&out, command->suspendPolicy);
    (void)outStream_writeInt(&out, 1);   /* Always one component */
    (void)outStream_writeByte(&out, JDWP_EVENT(VM_INIT));
    (void)outStream_writeInt(&out, 0);    /* Not in response to an event req. */

    (void)outStream_writeObjectRef(env, &out, command->thread);

    outStream_sendCommand(&out);
    outStream_destroy(&out);
    /* Why aren't we tossing this: tossGlobalRef(env, &(command->thread)); */
}

static void
handleSuspendThreadCommand(JNIEnv* env, SuspendThreadCommand *command) 
{
    /*
     * For the moment, there's  nothing that can be done with the 
     * return code, so we don't check it here. 
     */
    (void)threadControl_suspendThread(command->thread, JNI_TRUE);
    tossGlobalRef(env, &(command->thread));
}

static void
handleCommand(JNIEnv *env, HelperCommand *command)
{
    switch (command->commandKind) {
        case COMMAND_REPORT_EVENT_COMPOSITE:
            handleReportEventCompositeCommand(env, 
                                        &command->u.reportEventComposite);
            break;
        case COMMAND_REPORT_INVOKE_DONE:
            handleReportInvokeDoneCommand(env, &command->u.reportInvokeDone);
            break;
        case COMMAND_REPORT_VM_INIT:
            handleReportVMInitCommand(env, &command->u.reportVMInit);
            break; 
        case COMMAND_SUSPEND_THREAD:
            handleSuspendThreadCommand(env, &command->u.suspendThread);
            break; 
        default:
            EXIT_ERROR(AGENT_ERROR_INVALID_EVENT_TYPE,"Event Helper Command");
            break;
    }
}

/*
 * There was an assumption that only one event with a suspend-all
 * policy could be processed by commandLoop() at one time. It was
 * assumed that native thread suspension from the first suspend-all
 * event would prevent the second suspend-all event from making it
 * into the command queue. For the Classic VM, this was a reasonable
 * assumption. However, in HotSpot all thread suspension requires a
 * VM operation and VM operations take time.
 *
 * The solution is to add a mechanism to prevent commandLoop() from
 * processing more than one event with a suspend-all policy. This is
 * accomplished by forcing commandLoop() to wait for either
 * ThreadReferenceImpl.c: resume() or VirtualMachineImpl.c: resume()
 * when an event with a suspend-all policy has been completed.
 */
static jboolean blockCommandLoop = JNI_FALSE;

/*
 * We wait for either ThreadReferenceImpl.c: resume() or
 * VirtualMachineImpl.c: resume() to be called.
 */
static void
doBlockCommandLoop(void) {
    debugMonitorEnter(blockCommandLoopLock);
    while (blockCommandLoop == JNI_TRUE) {
        debugMonitorWait(blockCommandLoopLock);
    }
    debugMonitorExit(blockCommandLoopLock);
}

/*
 * If the command that we are about to execute has a suspend-all
 * policy, then prepare for either ThreadReferenceImpl.c: resume()
 * or VirtualMachineImpl.c: resume() to be called.
 */
static jboolean
needBlockCommandLoop(HelperCommand *cmd) {
    if (cmd->commandKind == COMMAND_REPORT_EVENT_COMPOSITE
    && cmd->u.reportEventComposite.suspendPolicy == JDWP_SUSPEND_POLICY(ALL)) {
        debugMonitorEnter(blockCommandLoopLock);
        blockCommandLoop = JNI_TRUE;
        debugMonitorExit(blockCommandLoopLock);

        return JNI_TRUE;
    }

    return JNI_FALSE;
}

/*
 * Used by either ThreadReferenceImpl.c: resume() or
 * VirtualMachineImpl.c: resume() to resume commandLoop().
 */
void
unblockCommandLoop(void) {
    debugMonitorEnter(blockCommandLoopLock);
    blockCommandLoop = JNI_FALSE;
    debugMonitorNotifyAll(blockCommandLoopLock);
    debugMonitorExit(blockCommandLoopLock);
}

/*
 * The event helper thread. Dequeues commands and processes them.
 */
static void JNICALL
commandLoop(jvmtiEnv* jvmti_env, JNIEnv* jni_env, void* arg)
{
    LOG_MISC(("Begin command loop thread"));

    while (JNI_TRUE) {
        HelperCommand *command = dequeueCommand();
        if (command != NULL) {
            /*
             * Setup for a potential doBlockCommand() call before calling
             * handleCommand() to prevent any races.
             */
            jboolean doBlock = needBlockCommandLoop(command);
            log_debugee_location("commandLoop(): command being handled", NULL, NULL, 0);
            handleCommand(jni_env, command);
            completeCommand(command);
            /* if we just finished a suspend-all cmd, then we block here */
            if (doBlock) {
                doBlockCommandLoop();
            }
        } else {
          JDI_ASSERT(shutdownEvents);
          break;
        }
    }
    /* This loop never ends, even as connections come and go with server=y */
}

void 
eventHelper_initialize(jbyte sessionID)
{
    jvmtiStartFunction func;
    
    currentSessionID = sessionID;
    holdEvents = JNI_FALSE;
    shutdownEvents = JNI_FALSE;
    commandQueue.head = NULL;
    commandQueue.tail = NULL;

    commandQueueLock = debugMonitorCreate("JDWP Event Helper Queue Monitor");
    commandCompleteLock = debugMonitorCreate("JDWP Event Helper Completion Monitor");
    blockCommandLoopLock = debugMonitorCreate("JDWP Event Block CommandLoop Monitor");

    /* Start the event handler thread */
    func = &commandLoop;
    (void)spawnNewThread(func, NULL, "JDWP Event Helper Thread");
}

void 
eventHelper_reset(jbyte newSessionID)
{
    debugMonitorEnter(commandQueueLock);
    currentSessionID = newSessionID;
    holdEvents = JNI_FALSE;
    debugMonitorNotifyAll(commandQueueLock);
    debugMonitorExit(commandQueueLock);
}

void
eventHelper_shutdown(void)
{
    debugMonitorEnter(commandQueueLock);
    holdEvents = JNI_FALSE;
    shutdownEvents = JNI_TRUE;
    debugMonitorNotifyAll(commandQueueLock);
    debugMonitorExit(commandQueueLock);
}

/*
 * Provide a means for threadControl to ensure that crucial locks are not 
 * held by suspended threads.
 */
void 
eventHelper_lock(void)
{