/*

 * Copyright (c) 1998, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include <ctype.h>

#include "util.h"

#include "commonRef.h"

#include "debugDispatch.h"

#include "eventHandler.h"

#include "eventHelper.h"

#include "threadControl.h"

#include "stepControl.h"

#include "transport.h"

#include "classTrack.h"

#include "debugLoop.h"

#include "bag.h"

#include "invoker.h"

#include "sys.h"

/* How the options get to OnLoad: */

#define XRUN "-Xrunjdwp"

#define AGENTLIB "-agentlib:jdwp"

/* Debug version defaults */

#ifdef DEBUG

    #define DEFAULT_ASSERT_ON           JNI_TRUE

    #define DEFAULT_ASSERT_FATAL        JNI_TRUE

    #define DEFAULT_LOGFILE             "jdwp.log"

#else

    #define DEFAULT_ASSERT_ON           JNI_FALSE

    #define DEFAULT_ASSERT_FATAL        JNI_FALSE

    #define DEFAULT_LOGFILE             NULL

#endif

static jboolean vmInitialized;

static jrawMonitorID initMonitor;

static jboolean initComplete;

static jbyte currentSessionID;

/*

 * Options set through the OnLoad options string. All of these values

 * are set once at VM startup and never reset.

 */

static jboolean isServer = JNI_FALSE;     /* Listens for connecting debuggers? */

static jboolean isStrict = JNI_FALSE;     /* Unused */

static jboolean useStandardAlloc = JNI_FALSE;  /* Use standard malloc/free? */

static struct bag *transports;            /* of TransportSpec */

static jboolean initOnStartup = JNI_TRUE;   /* init immediately */

static char *initOnException = NULL;        /* init when this exception thrown */

static jboolean initOnUncaught = JNI_FALSE; /* init when uncaught exc thrown */

static char *launchOnInit = NULL;           /* launch this app during init */

static jboolean suspendOnInit = JNI_TRUE;   /* suspend all app threads after init */

static jboolean dopause = JNI_FALSE;        /* pause for debugger attach */

static jboolean docoredump = JNI_FALSE;     /* core dump on exit */

static char *logfile = NULL;                /* Name of logfile (if logging) */

static unsigned logflags = 0;               /* Log flags */

static char *names;                         /* strings derived from OnLoad options */

static jboolean allowStartViaJcmd = JNI_FALSE;  /* if true we allow the debugging to be started via a jcmd */

static jboolean startedViaJcmd = JNI_FALSE;     /* if false, we have not yet started debugging via a jcmd */

/*

 * Elements of the transports bag

 */

typedef struct TransportSpec {

    char *name;

    char *address;

    long timeout;

    char *allow;

} TransportSpec;

/*

 * Forward Refs

 */

static void JNICALL cbEarlyVMInit(jvmtiEnv*, JNIEnv *, jthread);

static void JNICALL cbEarlyVMDeath(jvmtiEnv*, JNIEnv *);

static void JNICALL cbEarlyException(jvmtiEnv*, JNIEnv *,

            jthread, jmethodID, jlocation, jobject, jmethodID, jlocation);

static void initialize(JNIEnv *env, jthread thread, EventIndex triggering_ei);

static jboolean parseOptions(char *str);

/*

 * Phase 1: Initial load.

 *

 * OnLoad is called by the VM immediately after the back-end

 * library is loaded. We can do very little in this function since

 * the VM has not completed initialization. So, we parse the JDWP

 * options and set up a simple initial event callbacks for JVMTI events.

 * When a triggering event occurs, that callback will begin debugger initialization.

 */

/* Get a static area to hold the Global Data */

static BackendGlobalData *

get_gdata(void)

{

    static BackendGlobalData s;

    (void)memset(&s, 0, sizeof(BackendGlobalData));

    return &s;

}

static jvmtiError

set_event_notification(jvmtiEventMode mode, EventIndex ei)

{

    jvmtiError error;

    error = JVMTI_FUNC_PTR(gdata->jvmti,SetEventNotificationMode)

                (gdata->jvmti, mode, eventIndex2jvmti(ei), NULL);

    if (error != JVMTI_ERROR_NONE) {

        ERROR_MESSAGE(("JDWP unable to configure initial JVMTI event %s: %s(%d)",

                    eventText(ei), jvmtiErrorText(error), error));

    }

    return error;

}

typedef struct {

    int major;

    int minor;

} version_type;

typedef struct {

    version_type runtime;

    version_type compiletime;

} compatible_versions_type;

/*

 * List of explicitly compatible JVMTI versions, specified as

 * { runtime version, compile-time version } pairs. -1 is a wildcard.

 */

static int nof_compatible_versions = 3;

static compatible_versions_type compatible_versions_list[] = {

    /*

     * FIXUP: Allow version 0 to be compatible with anything

     * Special check for FCS of 1.0.

     */

    { {  0, -1 }, { -1, -1 } },

    { { -1, -1 }, {  0, -1 } },

    /*

     * 1.2 is runtime compatible with 1.1 -- just make sure to check the

     * version before using any new 1.2 features

     */

    { {  1,  1 }, {  1,  2 } }

};

/* Logic to determine JVMTI version compatibility */

static jboolean

compatible_versions(jint major_runtime,     jint minor_runtime,

                    jint major_compiletime, jint minor_compiletime)

{

    /*

     * First check to see if versions are explicitly compatible via the

     * list specified above.

     */

    int i;

    for (i = 0; i < nof_compatible_versions; ++i) {

        version_type runtime = compatible_versions_list[i].runtime;

        version_type comptime = compatible_versions_list[i].compiletime;

        if ((major_runtime     == runtime.major  || runtime.major  == -1) &&

            (minor_runtime     == runtime.minor  || runtime.minor  == -1) &&

            (major_compiletime == comptime.major || comptime.major == -1) &&

            (minor_compiletime == comptime.minor || comptime.minor == -1)) {

            return JNI_TRUE;

        }

    }

    return major_runtime == major_compiletime &&

           minor_runtime >= minor_compiletime;

}

/* OnLoad startup:

 *   Returning JNI_ERR will cause the java_g VM to core dump, be careful.

 */

JNIEXPORT jint JNICALL

DEF_Agent_OnLoad(JavaVM *vm, char *options, void *reserved)

{

    jvmtiError error;

    jvmtiCapabilities needed_capabilities;

    jvmtiCapabilities potential_capabilities;

    jint              jvmtiCompileTimeMajorVersion;

    jint              jvmtiCompileTimeMinorVersion;

    jint              jvmtiCompileTimeMicroVersion;

    /* See if it's already loaded */

    if ( gdata!=NULL && gdata->isLoaded==JNI_TRUE ) {

        ERROR_MESSAGE(("Cannot load this JVM TI agent twice, check your java command line for duplicate jdwp options."));

        return JNI_ERR;

    }

    /* If gdata is defined and the VM died, why are we here? */

    if ( gdata!=NULL && gdata->vmDead ) {

        ERROR_MESSAGE(("JDWP unable to load, VM died"));

        return JNI_ERR;

    }

    /* Get global data area */

    gdata = get_gdata();

    if (gdata == NULL) {

        ERROR_MESSAGE(("JDWP unable to allocate memory"));

        return JNI_ERR;

    }

    gdata->isLoaded = JNI_TRUE;

    /* Start filling in gdata */

    gdata->jvm = vm;

    vmInitialized = JNI_FALSE;

    gdata->vmDead = JNI_FALSE;

    /* Get the JVMTI Env, IMPORTANT: Do this first! For jvmtiAllocate(). */

    error = JVM_FUNC_PTR(vm,GetEnv)

                (vm, (void **)&(gdata->jvmti), JVMTI_VERSION_1);

    if (error != JNI_OK) {

        ERROR_MESSAGE(("JDWP unable to access JVMTI Version 1 (0x%x),"

                         " is your J2SE a 1.5 or newer version?"

                         " JNIEnv's GetEnv() returned %d",

                         JVMTI_VERSION_1, error));

        forceExit(1); /* Kill entire process, no core dump */

    }

    /* Check to make sure the version of jvmti.h we compiled with

     *      matches the runtime version we are using.

     */

    jvmtiCompileTimeMajorVersion  = ( JVMTI_VERSION & JVMTI_VERSION_MASK_MAJOR )

                                        >> JVMTI_VERSION_SHIFT_MAJOR;

    jvmtiCompileTimeMinorVersion  = ( JVMTI_VERSION & JVMTI_VERSION_MASK_MINOR )

                                        >> JVMTI_VERSION_SHIFT_MINOR;

    jvmtiCompileTimeMicroVersion  = ( JVMTI_VERSION & JVMTI_VERSION_MASK_MICRO )

                                        >> JVMTI_VERSION_SHIFT_MICRO;

    /* Check for compatibility */

    if ( !compatible_versions(jvmtiMajorVersion(), jvmtiMinorVersion(),

                jvmtiCompileTimeMajorVersion, jvmtiCompileTimeMinorVersion) ) {

        ERROR_MESSAGE(("This jdwp native library will not work with this VM's "

                       "version of JVMTI (%d.%d.%d), it needs JVMTI %d.%d[.%d].",

                       jvmtiMajorVersion(),

                       jvmtiMinorVersion(),

                       jvmtiMicroVersion(),

                       jvmtiCompileTimeMajorVersion,

                       jvmtiCompileTimeMinorVersion,

                       jvmtiCompileTimeMicroVersion));

        /* Do not let VM get a fatal error, we don't want a core dump here. */

        forceExit(1); /* Kill entire process, no core dump wanted */

    }

    /* Parse input options */

    if (!parseOptions(options)) {

        /* No message necessary, should have been printed out already */

        /* Do not let VM get a fatal error, we don't want a core dump here. */

        forceExit(1); /* Kill entire process, no core dump wanted */

    }

    LOG_MISC(("Onload: %s", options));

    /* Get potential capabilities */

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

    error = JVMTI_FUNC_PTR(gdata->jvmti,GetPotentialCapabilities)

                (gdata->jvmti, &potential_capabilities);

    if (error != JVMTI_ERROR_NONE) {

        ERROR_MESSAGE(("JDWP unable to get potential JVMTI capabilities: %s(%d)",

                        jvmtiErrorText(error), error));

        return JNI_ERR;

    }

    /* Fill in ones that we must have */

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

    needed_capabilities.can_access_local_variables              = 1;

    needed_capabilities.can_generate_single_step_events         = 1;

    needed_capabilities.can_generate_exception_events           = 1;

    needed_capabilities.can_generate_frame_pop_events           = 1;

    needed_capabilities.can_generate_breakpoint_events          = 1;

    needed_capabilities.can_suspend                             = 1;

    needed_capabilities.can_generate_method_entry_events        = 1;

    needed_capabilities.can_generate_method_exit_events         = 1;

    needed_capabilities.can_generate_garbage_collection_events  = 1;

    needed_capabilities.can_maintain_original_method_order      = 1;

    needed_capabilities.can_generate_monitor_events             = 1;

    needed_capabilities.can_tag_objects                         = 1;

    /* And what potential ones that would be nice to have */

    needed_capabilities.can_force_early_return

                = potential_capabilities.can_force_early_return;

    needed_capabilities.can_generate_field_modification_events

                = potential_capabilities.can_generate_field_modification_events;

    needed_capabilities.can_generate_field_access_events

                = potential_capabilities.can_generate_field_access_events;

    needed_capabilities.can_get_bytecodes

                = potential_capabilities.can_get_bytecodes;

    needed_capabilities.can_get_synthetic_attribute

                = potential_capabilities.can_get_synthetic_attribute;

    needed_capabilities.can_get_owned_monitor_info

                = potential_capabilities.can_get_owned_monitor_info;

    needed_capabilities.can_get_current_contended_monitor

                = potential_capabilities.can_get_current_contended_monitor;

    needed_capabilities.can_get_monitor_info

                = potential_capabilities.can_get_monitor_info;

    needed_capabilities.can_pop_frame

                = potential_capabilities.can_pop_frame;

    needed_capabilities.can_redefine_classes

                = potential_capabilities.can_redefine_classes;

    needed_capabilities.can_redefine_any_class

                = potential_capabilities.can_redefine_any_class;

    needed_capabilities.can_get_owned_monitor_stack_depth_info

        = potential_capabilities.can_get_owned_monitor_stack_depth_info;

    needed_capabilities.can_get_constant_pool

                = potential_capabilities.can_get_constant_pool;

    {

        needed_capabilities.can_get_source_debug_extension      = 1;

        needed_capabilities.can_get_source_file_name            = 1;

        needed_capabilities.can_get_line_numbers                = 1;

        needed_capabilities.can_signal_thread

                = potential_capabilities.can_signal_thread;

    }

    /* Add the capabilities */

    error = JVMTI_FUNC_PTR(gdata->jvmti,AddCapabilities)

                (gdata->jvmti, &needed_capabilities);

    if (error != JVMTI_ERROR_NONE) {

        ERROR_MESSAGE(("JDWP unable to get necessary JVMTI capabilities."));

        forceExit(1); /* Kill entire process, no core dump wanted */

    }

    /* Initialize event number mapping tables */

    eventIndexInit();

    /* Set the initial JVMTI event notifications */

    error = set_event_notification(JVMTI_ENABLE, EI_VM_DEATH);

    if (error != JVMTI_ERROR_NONE) {

        return JNI_ERR;

    }

    error = set_event_notification(JVMTI_ENABLE, EI_VM_INIT);

    if (error != JVMTI_ERROR_NONE) {

        return JNI_ERR;

    }

    if (initOnUncaught || (initOnException != NULL)) {

        error = set_event_notification(JVMTI_ENABLE, EI_EXCEPTION);

        if (error != JVMTI_ERROR_NONE) {

            return JNI_ERR;

        }

    }

    /* Set callbacks just for 3 functions */

    (void)memset(&(gdata->callbacks),0,sizeof(gdata->callbacks));

    gdata->callbacks.VMInit             = &cbEarlyVMInit;

    gdata->callbacks.VMDeath            = &cbEarlyVMDeath;

    gdata->callbacks.Exception  = &cbEarlyException;

    error = JVMTI_FUNC_PTR(gdata->jvmti,SetEventCallbacks)

                (gdata->jvmti, &(gdata->callbacks), sizeof(gdata->callbacks));

    if (error != JVMTI_ERROR_NONE) {

        ERROR_MESSAGE(("JDWP unable to set JVMTI event callbacks: %s(%d)",

                        jvmtiErrorText(error), error));

        return JNI_ERR;

    }

    LOG_MISC(("OnLoad: DONE"));

    return JNI_OK;

}

JNIEXPORT void JNICALL

DEF_Agent_OnUnload(JavaVM *vm)

{

    gdata->isLoaded = JNI_FALSE;

    /* Cleanup, but make sure VM is alive before using JNI, and

     *   make sure JVMTI environment is ok before deallocating

     *   memory allocated through JVMTI, which all of it is.

     */

    /*

     * Close transport before exit

     */

    if (transport_is_open()) {

        transport_close();

    }

}

/*

 * Phase 2: Initial events. Phase 2 consists of waiting for the

 * event that triggers full initialization. Under normal circumstances

 * (initOnStartup == TRUE) this is the JVMTI_EVENT_VM_INIT event.

 * Otherwise, we delay initialization until the app throws a

 * particular exception. The triggering event invokes

 * the bulk of the initialization, including creation of threads and

 * monitors, transport setup, and installation of a new event callback which

 * handles the complete set of events.

 *

 * Since the triggering event comes in on an application thread, some of the

 * initialization is difficult to do here. Specifically, this thread along

 * with all other app threads may need to be suspended until a debugger

 * connects. These kinds of tasks are left to the third phase which is

 * invoked by one of the spawned debugger threads, the event handler.

 */

/*

 * Wait for a triggering event; then kick off debugger

 * initialization. A different event callback will be installed by

 * debugger initialization, and this function will not be called

 * again.

 */

    /*

     * TO DO: Decide whether we need to protect this code with

     * a lock. It might be too early to create a monitor safely (?).

     */

static void JNICALL

cbEarlyVMInit(jvmtiEnv *jvmti_env, JNIEnv *env, jthread thread)

{

    LOG_CB(("cbEarlyVMInit"));

    if ( gdata->vmDead ) {

        EXIT_ERROR(AGENT_ERROR_INTERNAL,"VM dead at VM_INIT time");

    }

    if (initOnStartup)

        initialize(env, thread, EI_VM_INIT);

    vmInitialized = JNI_TRUE;

    LOG_MISC(("END cbEarlyVMInit"));

}

static void

disposeEnvironment(jvmtiEnv *jvmti_env)

{

    jvmtiError error;

    error = JVMTI_FUNC_PTR(jvmti_env,DisposeEnvironment)(jvmti_env);

    if ( error == JVMTI_ERROR_MUST_POSSESS_CAPABILITY )

        error = JVMTI_ERROR_NONE;  /* Hack!  FIXUP when JVMTI has disposeEnv */

    /* What should error return say? */

    if (error != JVMTI_ERROR_NONE) {

        ERROR_MESSAGE(("JDWP unable to dispose of JVMTI environment: %s(%d)",

                        jvmtiErrorText(error), error));

    }

    gdata->jvmti = NULL;

}

static void JNICALL

cbEarlyVMDeath(jvmtiEnv *jvmti_env, JNIEnv *env)

{

    LOG_CB(("cbEarlyVMDeath"));

    if ( gdata->vmDead ) {

        EXIT_ERROR(AGENT_ERROR_INTERNAL,"VM died more than once");

    }

    disposeEnvironment(jvmti_env);

    gdata->jvmti = NULL;

    gdata->jvm = NULL;

    gdata->vmDead = JNI_TRUE;

    LOG_MISC(("END cbEarlyVMDeath"));

}

static void JNICALL

cbEarlyException(jvmtiEnv *jvmti_env, JNIEnv *env,

        jthread thread, jmethodID method, jlocation location,

        jobject exception,

        jmethodID catch_method, jlocation catch_location)

{

    jvmtiError error;

    jthrowable currentException;

    LOG_CB(("cbEarlyException: thread=%p", thread));

    if ( gdata->vmDead ) {

        EXIT_ERROR(AGENT_ERROR_INTERNAL,"VM dead at initial Exception event");

    }

    if (!vmInitialized)  {

        LOG_MISC(("VM is not initialized yet"));

        return;

    }

    /*

     * We want to preserve any current exception that might get wiped

     * out during event handling (e.g. JNI calls). We have to rely on

     * space for the local reference on the current frame because

     * doing a PushLocalFrame here might itself generate an exception.

     */

    currentException = JNI_FUNC_PTR(env,ExceptionOccurred)(env);

    JNI_FUNC_PTR(env,ExceptionClear)(env);

    if (initOnUncaught && catch_method == NULL) {

        LOG_MISC(("Initializing on uncaught exception"));

        initialize(env, thread, EI_EXCEPTION);

    } else if (initOnException != NULL) {

        jclass clazz;

        /* Get class of exception thrown */

        clazz = JNI_FUNC_PTR(env,GetObjectClass)(env, exception);

        if ( clazz != NULL ) {

            char *signature = NULL;

            /* initing on throw, check */

            error = classSignature(clazz, &signature, NULL);

            LOG_MISC(("Checking specific exception: looking for %s, got %s",

                        initOnException, signature));

            if ( (error==JVMTI_ERROR_NONE) &&

                (strcmp(signature, initOnException) == 0)) {