/*

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 *   - Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 *

 *   - Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution.

 *

 *   - Neither the name of Oracle nor the names of its

 *     contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/*

 * This source code is provided to illustrate the usage of a given feature

 * or technique and has been deliberately simplified. Additional steps

 * required for a production-quality application, such as security checks,

 * input validation and proper error handling, might not be present in

 * this sample code.

 */

/* Example of using JVMTI events:

 *      JVMTI_EVENT_VM_INIT

 *      JVMTI_EVENT_VM_DEATH

 *      JVMTI_EVENT_THREAD_START

 *      JVMTI_EVENT_THREAD_END

 *      JVMTI_EVENT_MONITOR_CONTENDED_ENTER

 *      JVMTI_EVENT_MONITOR_WAIT

 *      JVMTI_EVENT_MONITOR_WAITED

 *      JVMTI_EVENT_OBJECT_FREE

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "jni.h"

#include "jvmti.h"

#include "agent_util.h"

#include "Monitor.hpp"

#include "Thread.hpp"

#include "Agent.hpp"

static jrawMonitorID vm_death_lock;

static jboolean      vm_death_active;

/* Given a jvmtiEnv*, return the C++ Agent class instance */

static Agent *

get_agent(jvmtiEnv *jvmti)

{

    jvmtiError err;

    Agent     *agent;

    agent = NULL;

    err = jvmti->GetEnvironmentLocalStorage((void**)&agent);

    check_jvmti_error(jvmti, err, "get env local storage");

    if ( agent == NULL ) {

        /* This should never happen, but we should check */

        fatal_error("ERROR: GetEnvironmentLocalStorage() returned NULL");

    }

    return agent;

}

/* Enter raw monitor */

static void

menter(jvmtiEnv *jvmti, jrawMonitorID rmon)

{

    jvmtiError err;

    err = jvmti->RawMonitorEnter(rmon);

    check_jvmti_error(jvmti, err, "raw monitor enter");

}

/* Exit raw monitor */

static void

mexit(jvmtiEnv *jvmti, jrawMonitorID rmon)

{

    jvmtiError err;

    err = jvmti->RawMonitorExit(rmon);

    check_jvmti_error(jvmti, err, "raw monitor exit");

}

/* All callbacks need to be extern "C" */

extern "C" {

    static void JNICALL

    vm_init(jvmtiEnv *jvmti, JNIEnv *env, jthread thread)

    {

        jvmtiError err;

        Agent     *agent;

        /* Create raw monitor to protect against threads running after death */

        err = jvmti->CreateRawMonitor("Waiters vm_death lock", &vm_death_lock);

        check_jvmti_error(jvmti, err, "create raw monitor");

        vm_death_active = JNI_FALSE;

        /* Create an Agent instance, set JVMTI Local Storage */

        agent = new Agent(jvmti, env, thread);

        err = jvmti->SetEnvironmentLocalStorage((const void*)agent);

        check_jvmti_error(jvmti, err, "set env local storage");

        /* Enable all other events we want */

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

                        JVMTI_EVENT_VM_DEATH, NULL);

        check_jvmti_error(jvmti, err, "set event notify");

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

                        JVMTI_EVENT_THREAD_START, NULL);

        check_jvmti_error(jvmti, err, "set event notify");

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

                        JVMTI_EVENT_THREAD_END, NULL);

        check_jvmti_error(jvmti, err, "set event notify");

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

                        JVMTI_EVENT_MONITOR_CONTENDED_ENTER, NULL);

        check_jvmti_error(jvmti, err, "set event notify");

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

                        JVMTI_EVENT_MONITOR_CONTENDED_ENTERED, NULL);

        check_jvmti_error(jvmti, err, "set event notify");

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

                        JVMTI_EVENT_MONITOR_WAIT, NULL);

        check_jvmti_error(jvmti, err, "set event notify");

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

                        JVMTI_EVENT_MONITOR_WAITED, NULL);

        check_jvmti_error(jvmti, err, "set event notify");

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

                        JVMTI_EVENT_OBJECT_FREE, NULL);

        check_jvmti_error(jvmti, err, "set event notify");

    }

    static void JNICALL

    vm_death(jvmtiEnv *jvmti, JNIEnv *env)

    {

        jvmtiError err;

        Agent     *agent;

        /* Block all callbacks */

        menter(jvmti, vm_death_lock); {

            /* Set flag for other callbacks */

            vm_death_active = JNI_TRUE;

            /* Inform Agent instance of VM_DEATH */

            agent = get_agent(jvmti);

            agent->vm_death(jvmti, env);

            /* Reclaim space of Agent */

            err = jvmti->SetEnvironmentLocalStorage((const void*)NULL);

            check_jvmti_error(jvmti, err, "set env local storage");

            delete agent;

        } mexit(jvmti, vm_death_lock);

    }

    static void JNICALL

    thread_start(jvmtiEnv *jvmti, JNIEnv *env, jthread thread)

    {

        menter(jvmti, vm_death_lock); {

            if ( !vm_death_active ) {

                get_agent(jvmti)->thread_start(jvmti, env, thread);

            }

        } mexit(jvmti, vm_death_lock);

    }

    static void JNICALL

    thread_end(jvmtiEnv *jvmti, JNIEnv *env, jthread thread)

    {

        menter(jvmti, vm_death_lock); {

            if ( !vm_death_active ) {

                get_agent(jvmti)->thread_end(jvmti, env, thread);

            }

        } mexit(jvmti, vm_death_lock);

    }

    static void JNICALL

    monitor_contended_enter(jvmtiEnv* jvmti, JNIEnv *env,

                 jthread thread, jobject object)

    {

        menter(jvmti, vm_death_lock); {

            if ( !vm_death_active ) {

                get_agent(jvmti)->monitor_contended_enter(jvmti, env,

                                                          thread, object);

            }

        } mexit(jvmti, vm_death_lock);

    }

    static void JNICALL

    monitor_contended_entered(jvmtiEnv* jvmti, JNIEnv *env,

                   jthread thread, jobject object)

    {

        menter(jvmti, vm_death_lock); {

            if ( !vm_death_active ) {

                get_agent(jvmti)->monitor_contended_entered(jvmti, env,

                                                            thread, object);

            }

        } mexit(jvmti, vm_death_lock);

    }

    static void JNICALL

    monitor_wait(jvmtiEnv* jvmti, JNIEnv *env,

                 jthread thread, jobject object, jlong timeout)

    {

        menter(jvmti, vm_death_lock); {

            if ( !vm_death_active ) {

                get_agent(jvmti)->monitor_wait(jvmti, env, thread,

                                               object, timeout);

            }

        } mexit(jvmti, vm_death_lock);

    }

    static void JNICALL

    monitor_waited(jvmtiEnv* jvmti, JNIEnv *env,

                   jthread thread, jobject object, jboolean timed_out)

    {

        menter(jvmti, vm_death_lock); {

            if ( !vm_death_active ) {

                get_agent(jvmti)->monitor_waited(jvmti, env, thread,

                                                 object, timed_out);

            }

        } mexit(jvmti, vm_death_lock);

    }

    static void JNICALL

    object_free(jvmtiEnv* jvmti, jlong tag)

    {

        menter(jvmti, vm_death_lock); {

            if ( !vm_death_active ) {

                get_agent(jvmti)->object_free(jvmti, tag);

            }

        } mexit(jvmti, vm_death_lock);

    }

    /* Agent_OnLoad() is called first, we prepare for a VM_INIT event here. */

    JNIEXPORT jint JNICALL

    {

        jvmtiEnv           *jvmti;

        jint                rc;

        jvmtiError          err;

        jvmtiCapabilities   capabilities;

        jvmtiEventCallbacks callbacks;

        /* Get JVMTI environment */

        rc = vm->GetEnv((void **)&jvmti, JVMTI_VERSION);

        if (rc != JNI_OK) {

            fatal_error("ERROR: Unable to create jvmtiEnv, GetEnv failed, error=%d\n", rc);

            return -1;

        }

        /* Get/Add JVMTI capabilities */

        (void)memset(&capabilities, 0, sizeof(capabilities));

        capabilities.can_generate_monitor_events        = 1;

        capabilities.can_get_monitor_info               = 1;

        capabilities.can_tag_objects                    = 1;

        capabilities.can_generate_object_free_events    = 1;

        err = jvmti->AddCapabilities(&capabilities);

        check_jvmti_error(jvmti, err, "add capabilities");

        /* Set all callbacks and enable VM_INIT event notification */

        memset(&callbacks, 0, sizeof(callbacks));

        callbacks.VMInit                  = &vm_init;

        callbacks.VMDeath                 = &vm_death;

        callbacks.ThreadStart             = &thread_start;

        callbacks.ThreadEnd               = &thread_end;

        callbacks.MonitorContendedEnter   = &monitor_contended_enter;

        callbacks.MonitorContendedEntered = &monitor_contended_entered;

        callbacks.MonitorWait             = &monitor_wait;

        callbacks.MonitorWaited           = &monitor_waited;

        callbacks.ObjectFree              = &object_free;

        err = jvmti->SetEventCallbacks(&callbacks, (jint)sizeof(callbacks));

        check_jvmti_error(jvmti, err, "set event callbacks");

        err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

                        JVMTI_EVENT_VM_INIT, NULL);

        check_jvmti_error(jvmti, err, "set event notify");

        return 0;

    }

    /* Agent_OnUnload() is called last */

    JNIEXPORT void JNICALL

    {

    }

} /* of extern "C" */