1 /* 2 * Copyright (c) 2019, Red Hat, Inc. All rights reserved. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #include <stdio.h> 25 #include <string.h> 26 #include "jvmti.h" 27 28 #ifdef __cplusplus 29 extern "C" { 30 #endif 31 32 #ifndef JNI_ENV_ARG 33 34 #ifdef __cplusplus 35 #define JNI_ENV_ARG(x, y) y 36 #define JNI_ENV_PTR(x) x 37 #else 38 #define JNI_ENV_ARG(x,y) x, y 39 #define JNI_ENV_PTR(x) (*x) 40 #endif 41 42 #endif 43 44 static const char *EXC_CNAME = "java/lang/Exception"; 45 46 static jvmtiEnv *jvmti = NULL; 47 48 static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved); 49 50 JNIEXPORT 51 jint JNICALL Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) { 52 return Agent_Initialize(jvm, options, reserved); 53 } 54 55 JNIEXPORT 56 jint JNICALL Agent_OnAttach(JavaVM *jvm, char *options, void *reserved) { 57 return Agent_Initialize(jvm, options, reserved); 58 } 59 60 JNIEXPORT 61 jint JNICALL JNI_OnLoad(JavaVM *jvm, void *reserved) { 62 return JNI_VERSION_1_8; 63 } 64 65 static 66 jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) { 67 jvmtiCapabilities capabilities; 68 jint res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &jvmti), 69 JVMTI_VERSION); 70 if (res != JNI_OK || jvmti == NULL) { 71 printf(" Error: wrong result of a valid call to GetEnv!\n"); 72 return JNI_ERR; 73 } 74 75 (void)memset(&capabilities, 0, sizeof(capabilities)); 76 capabilities.can_tag_objects = 1; 77 capabilities.can_generate_garbage_collection_events = 1; 78 (*jvmti)->AddCapabilities(jvmti, &capabilities); 79 80 return JNI_OK; 81 } 82 83 static 84 void throw_exc(JNIEnv *env, char *msg) { 85 jclass exc_class = JNI_ENV_PTR(env)->FindClass(JNI_ENV_ARG(env, EXC_CNAME)); 86 jint rt = JNI_OK; 87 88 if (exc_class == NULL) { 89 printf("throw_exc: Error in FindClass(env, %s)\n", EXC_CNAME); 90 return; 91 } 92 rt = JNI_ENV_PTR(env)->ThrowNew(JNI_ENV_ARG(env, exc_class), msg); 93 if (rt == JNI_ERR) { 94 printf("throw_exc: Error in JNI ThrowNew(env, %s)\n", msg); 95 } 96 } 97 98 JNIEXPORT jint JNICALL 99 Java_TestGetLoadedClasses_getLoadedClasses(JNIEnv *env, jclass cls) { 100 jint totalCount = 0; 101 jclass* classes; 102 if (jvmti == NULL) { 103 throw_exc(env, "JVMTI client was not properly loaded!\n"); 104 return 0; 105 } 106 107 (*jvmti)->GetLoadedClasses(jvmti, &totalCount, &classes); 108 (*jvmti)->Deallocate(jvmti, (unsigned char*)classes); 109 return totalCount; 110 } 111 112 #ifdef __cplusplus 113 } 114 #endif