/*

 * Copyright (c) 2016, 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.

 *

 * 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 <stdio.h>

#include <string.h>

#include "jvmti.h"

#ifdef __cplusplus

extern "C" {

#endif

#ifndef JNI_ENV_ARG

#ifdef __cplusplus

#define JNI_ENV_ARG(x, y) y

#define JNI_ENV_PTR(x) x

#else

#define JNI_ENV_ARG(x,y) x, y

#define JNI_ENV_PTR(x) (*x)

#endif

#endif

#define TranslateError(err) "JVMTI error"

#define PASSED 0

#define FAILED 2

static const char *EXC_CNAME = "java/lang/Exception";

static const char* MOD_CNAME = "Ljava/lang/reflect/Module;";

static jvmtiEnv *jvmti = NULL;

static jint result = PASSED;

static jboolean printdump = JNI_FALSE;

static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved);

JNIEXPORT

jint JNICALL Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {

    return Agent_Initialize(jvm, options, reserved);

}

JNIEXPORT

jint JNICALL Agent_OnAttach(JavaVM *jvm, char *options, void *reserved) {

    return Agent_Initialize(jvm, options, reserved);

}

JNIEXPORT

jint JNICALL JNI_OnLoad(JavaVM *jvm, void *reserved) {

    return JNI_VERSION_1_8;

}

static

jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {

    jint res;

    if (options != NULL && strcmp(options, "printdump") == 0) {

        printdump = JNI_TRUE;

    }

    res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &jvmti),

        JVMTI_VERSION_9);

    if (res != JNI_OK || jvmti == NULL) {

        printf("    Error: wrong result of a valid call to GetEnv!\n");

        return JNI_ERR;

    }

    return JNI_OK;

}

static

jint throw_exc(JNIEnv *env, char *msg) {

    jclass exc_class = JNI_ENV_PTR(env)->FindClass(JNI_ENV_ARG(env, EXC_CNAME));

    if (exc_class == NULL) {

        printf("throw_exc: Error in FindClass(env, %s)\n", EXC_CNAME);

        return -1;

    }

    return JNI_ENV_PTR(env)->ThrowNew(JNI_ENV_ARG(env, exc_class), msg);

}

static

jobject get_class_loader(jclass cls) {

    jvmtiError err = JVMTI_ERROR_NONE;

    jobject loader = NULL;

    if (printdump == JNI_TRUE) {

        printf(">>> getting class loader ...\n");

    }

    err = (*jvmti)->GetClassLoader(jvmti, cls, &loader);

    if (err != JVMTI_ERROR_NONE) {

        printf("    Error in GetClassLoader: %s (%d)\n", TranslateError(err), err);

    }

    return loader;

}

static

jclass jlrM(JNIEnv *env) {

    jclass cls = NULL;

    cls = JNI_ENV_PTR(env)->FindClass(JNI_ENV_ARG(env, MOD_CNAME));

    if (cls == NULL) {

        printf("    Error in JNI FindClass: %s\n", MOD_CNAME);

    }

    return cls;

}

jmethodID

get_method(JNIEnv *env, jclass clazz, const char * name, const char *sig) {

    jmethodID method = NULL;

    method = JNI_ENV_PTR(env)->GetMethodID(JNI_ENV_ARG(env, clazz), name, sig);

    if (method == NULL) {

        printf("    Error in JNI GetMethodID %s with signature %s", name, sig);

    }

    return method;

}

static

jobject get_module_loader(JNIEnv *env, jobject module) {

    static jmethodID cl_method = NULL;

    jobject loader = NULL;

    if (cl_method == NULL) {

        cl_method = get_method(env, jlrM(env), "getClassLoader", "()Ljava/lang/ClassLoader;");

    }

    loader = (jobject)JNI_ENV_PTR(env)->CallObjectMethod(JNI_ENV_ARG(env, module), cl_method);

    return loader;

}

static

const char* get_module_name(JNIEnv *env, jobject module) {

    static jmethodID method = NULL;

    jobject loader = NULL;

    jstring jstr = NULL;

    const char *name = NULL;

    const char *nstr = NULL;

    if (method == NULL) {

        method = get_method(env, jlrM(env), "getName", "()Ljava/lang/String;");

    }

    jstr = (jstring)JNI_ENV_PTR(env)->CallObjectMethod(JNI_ENV_ARG(env, module), method);

    if (jstr != NULL) {

        name = JNI_ENV_PTR(env)->GetStringUTFChars(JNI_ENV_ARG(env, jstr), NULL);

    }

    loader = get_module_loader(env, module);

    nstr = (name == NULL) ? "<UNNAMED>" : name;

    printf("    loader: %p, module: %p, name: %s\n", loader, module, nstr);

    return name;

}

static

jvmtiError get_module(JNIEnv *env,

                      jobject loader,

                      const char* pkg_name,

                      jobject* module_ptr,

                      const char** mod_name_ptr) {

    jvmtiError err = JVMTI_ERROR_NONE;

    const char* name = (pkg_name == NULL) ? "<NULL>" : pkg_name;

    printf(">>> getting module by loader %p and package \"%s\"\n", loader, name);

    *mod_name_ptr = NULL;

    err = (*jvmti)->GetNamedModule(jvmti, loader, pkg_name, module_ptr);

    if (err != JVMTI_ERROR_NONE) {

        printf("    Error in GetNamedModule for package \"%s\": %s (%d)\n",

               pkg_name, TranslateError(err), err);

        return err;

    }

    printf("    returned module: %p\n", *module_ptr);

    if (*module_ptr == NULL) { // named module was not found

        return err;

    }

    *mod_name_ptr = get_module_name(env, *module_ptr);

    return err;

}

static

jint get_all_modules(JNIEnv *env) {

    jvmtiError err;

    jint cnt = -1;

    jint idx = 0;

    jobject* modules;

    printf(">>> Inspecting modules with GetAllModules\n");

    err = (*jvmti)->GetAllModules(jvmti, &cnt, &modules);

    if (err != JVMTI_ERROR_NONE) {

        printf("Error in GetAllModules: %d\n", err);

        return -1;

    }

    for (idx = 0; idx < cnt; ++idx) {

        get_module_name(env, modules[idx]);

    }

    return cnt;

}

static

jint check_bad_loader(JNIEnv *env, jobject loader) {

    jvmtiError err = JVMTI_ERROR_NONE;

    jobject module = NULL;

    const char* mod_name = NULL;

    err = get_module(env, loader, "", &module, &mod_name);

    if (err != JVMTI_ERROR_ILLEGAL_ARGUMENT) {

        return FAILED;

    }

    printf("    got expected JVMTI_ERROR_ILLEGAL_ARGUMENT for bad loader\n");

    return PASSED;

}

static

jint check_system_loader(JNIEnv *env, jobject loader) {

    jvmtiError err = JVMTI_ERROR_NONE;

    jobject module = NULL;

    const char* exp_name = NULL;

    const char* mod_name = NULL;

    // NULL pointer for package name

    err = get_module(env, loader, NULL, &module, &mod_name);

    if (err != JVMTI_ERROR_NULL_POINTER) {

        throw_exc(env, "check #SN1: failed to return JVMTI_ERROR_NULL_POINTER for NULL package");

        return FAILED;

    }

    // NULL pointer for module_ptr

    err = (*jvmti)->GetNamedModule(jvmti, loader, "", NULL);

    if (err != JVMTI_ERROR_NULL_POINTER) {

        throw_exc(env, "check #SN2: failed to return JVMTI_ERROR_NULL_POINTER for NULL module_ptr");

        return FAILED;

    }

    // Unnamed/default package ""

    err = get_module(env, loader, "", &module, &mod_name);

    if (err != JVMTI_ERROR_NONE) {

        throw_exc(env, "check #S1: failed to return JVMTI_ERROR_NONE for default package");

        return FAILED;

    }

    if (module != NULL || mod_name != NULL) {

        throw_exc(env, "check #S2: failed to return NULL-module for default package");

        return FAILED;

    }

    // Test package: MyPackage

    err = get_module(env, loader, "MyPackage", &module, &mod_name);

    if (err != JVMTI_ERROR_NONE) {

        throw_exc(env, "check #S3: failed to return JVMTI_ERROR_NONE for MyPackage");

        return FAILED;

    }

    if (module != NULL || mod_name != NULL) {

        throw_exc(env, "check #S4: failed to return NULL-module for MyPackage");

        return FAILED;

    }

    // Package: com/sun/jdi

    exp_name = "jdk.jdi";

    err = get_module(env, loader, "com/sun/jdi", &module, &mod_name);

    if (err != JVMTI_ERROR_NONE) {

        throw_exc(env, "check #S5: failed to return JVMTI_ERROR_NONE for test package");

        return FAILED;

    }

    if (module == NULL || mod_name == NULL) {

        throw_exc(env, "check #S6: failed to return named module for com/sun/jdi package");

        return FAILED;

    }

    if (strcmp(mod_name, exp_name) != 0) {

        printf("check #S7: failed to return right module, expected: %s, returned: %s\n",

               exp_name, mod_name);

        throw_exc(env, "check #S7: failed to return jdk.jdi module for com/sun/jdi package");

        return FAILED;

    }

    // Non-existing package: "bad/package/name"

    err = get_module(env, loader, "bad/package/name", &module, &mod_name);

    if (err != JVMTI_ERROR_NONE) {

        throw_exc(env, "check #S8: failed to return JVMTI_ERROR_NONE for bad package");

        return FAILED;

    }

    if (module != NULL || mod_name != NULL) {

        throw_exc(env, "check #S9: failed to return NULL-module for bad package");

        return FAILED;

    }

    return PASSED;

}

static

jint check_bootstrap_loader(JNIEnv *env, jobject loader) {

    jvmtiError err = JVMTI_ERROR_NONE;

    jobject module = NULL;

    const char* exp_name = NULL;

    const char* mod_name = NULL;

    // NULL pointer for package name

    err = get_module(env, loader, NULL, &module, &mod_name);

    if (err != JVMTI_ERROR_NULL_POINTER) {

        throw_exc(env, "check #BN1: failed to return JVMTI_ERROR_NULL_POINTER for NULL package");

        return FAILED;

    }

    // NULL pointer for module_ptr

    err = (*jvmti)->GetNamedModule(jvmti, loader, "", NULL);

    if (err != JVMTI_ERROR_NULL_POINTER) {

        throw_exc(env, "check #BN2: failed to return JVMTI_ERROR_NULL_POINTER for NULL module_ptr");

        return FAILED;

    }

    // Unnamed/default package ""

    err = get_module(env, loader, "", &module, &mod_name);

    if (err != JVMTI_ERROR_NONE) {

        throw_exc(env, "check #B1: failed to return JVMTI_ERROR_NONE for default package");

        return FAILED;

    }

    if (module != NULL || mod_name != NULL) {

        throw_exc(env, "check #B2: failed to return NULL-module for default package");

        return FAILED;

    }

    // Normal package from java.base module: "java/lang"

    exp_name = "java.base";

    err = get_module(env, loader, "java/lang", &module, &mod_name);

    if (err != JVMTI_ERROR_NONE) {

        throw_exc(env, "check #B3: failed to return JVMTI_ERROR_NONE for java/lang package");

        return FAILED;

    }

    if (module == NULL || mod_name == NULL) {

        throw_exc(env, "check #B4: failed to return named module for java/lang package");

        return FAILED;

    }

    if (strcmp(exp_name, mod_name) != 0) {

        printf("check #B5: failed to return right module, expected: %s, returned: %s\n",

               exp_name, mod_name);

        throw_exc(env, "check #B5: failed to return expected module for java/lang package");

        return FAILED;

    }

    // Non-existing package: "bad/package/name"

    err = get_module(env, loader, "bad/package/name", &module, &mod_name);

    if (err != JVMTI_ERROR_NONE) {

        throw_exc(env, "check #B6: failed to return JVMTI_ERROR_NONE for bad package");

        return FAILED;

    }

    if (module != NULL || mod_name != NULL) {

        throw_exc(env, "check #B7: failed to return NULL-module for bad package");

        return FAILED;

    }

    return PASSED;

}

JNIEXPORT jint JNICALL

Java_MyPackage_GetNamedModuleTest_check(JNIEnv *env, jclass cls) {

    jobject loader = NULL;

    if (jvmti == NULL) {

        throw_exc(env, "JVMTI client was not properly loaded!\n");

        return FAILED;

    }

    get_all_modules(env);

    printf("\n*** Check for bad ClassLoader ***\n\n");

    result = check_bad_loader(env, (jobject)cls);

    if (result != PASSED) {

        throw_exc(env, "check #L1: failed to return JVMTI_ERROR_ILLEGAL_ARGUMENT for bad loader");

        return result;

    }

    loader = get_class_loader(cls);

    if (loader == NULL) {

        throw_exc(env, "check #L2: failed to return non-NULL loader for valid test class");

        return FAILED;

    }

    printf("\n*** Checks for System ClassLoader ***\n\n");

    result = check_system_loader(env, loader);

    if (result != PASSED) {

        return result;

    }

    printf("\n*** Checks for Bootstrap ClassLoader ***\n\n");

    result = check_bootstrap_loader(env, NULL);

    return result;

}

#ifdef __cplusplus

}

#endif