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// Copyright (C) 2019 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#include <android-base/logging.h>
#include <jni.h>
#include <jvmti.h>
namespace dumpjvmti {
namespace {
// Special art ti-version number. We will use this as a fallback if we cannot get a regular JVMTI
// env.
static constexpr jint kArtTiVersion = JVMTI_VERSION_1_2 | 0x40000000;
template <typename T> static void Dealloc(jvmtiEnv* env, T* t) {
env->Deallocate(reinterpret_cast<unsigned char*>(t));
}
template <typename T, typename... Rest> static void Dealloc(jvmtiEnv* env, T* t, Rest... rs) {
Dealloc(env, t);
Dealloc(env, rs...);
}
static void DeallocParams(jvmtiEnv* env, jvmtiParamInfo* params, jint n_params) {
for (jint i = 0; i < n_params; i++) {
Dealloc(env, params[i].name);
}
}
// The extension function to get the internal data
static jvmtiError (*GetInternalData)(jvmtiEnv* env, unsigned char** data) = nullptr;
static jint SetupJvmtiEnv(JavaVM* vm, jvmtiEnv** jvmti) {
jint res = 0;
res = vm->GetEnv(reinterpret_cast<void**>(jvmti), JVMTI_VERSION_1_1);
if (res != JNI_OK || *jvmti == nullptr) {
LOG(ERROR) << "Unable to access JVMTI, error code " << res;
res = vm->GetEnv(reinterpret_cast<void**>(jvmti), kArtTiVersion);
if (res != JNI_OK) {
return res;
}
}
jvmtiEnv* env = *jvmti;
// Get the extensions.
jint n_ext = 0;
jvmtiExtensionFunctionInfo* infos = nullptr;
if (env->GetExtensionFunctions(&n_ext, &infos) != JVMTI_ERROR_NONE) {
return JNI_ERR;
}
for (jint i = 0; i < n_ext; i++) {
jvmtiExtensionFunctionInfo* cur_info = &infos[i];
if (strcmp("com.android.art.misc.get_plugin_internal_state", cur_info->id) == 0) {
GetInternalData = reinterpret_cast<decltype(GetInternalData)>(cur_info->func);
}
// Cleanup the cur_info
DeallocParams(env, cur_info->params, cur_info->param_count);
Dealloc(env, cur_info->id, cur_info->short_description, cur_info->params, cur_info->errors);
}
// Cleanup the array.
Dealloc(env, infos);
return GetInternalData != nullptr ? JNI_OK : JNI_ERR;
}
static void CbDataDump(jvmtiEnv* jvmti) {
unsigned char* data = nullptr;
if (JVMTI_ERROR_NONE == GetInternalData(jvmti, &data)) {
LOG(INFO) << data;
Dealloc(jvmti, data);
}
}
} // namespace
static jint AgentStart(JavaVM* vm, char* options ATTRIBUTE_UNUSED, void* reserved ATTRIBUTE_UNUSED) {
jvmtiEnv* jvmti = nullptr;
if (SetupJvmtiEnv(vm, &jvmti) != JNI_OK) {
LOG(ERROR) << "Could not get JVMTI env or ArtTiEnv!";
return JNI_ERR;
}
jvmtiEventCallbacks cb{
.DataDumpRequest = CbDataDump,
};
jvmti->SetEventCallbacks(&cb, sizeof(cb));
jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_DATA_DUMP_REQUEST, nullptr);
return JNI_OK;
}
// Late attachment (e.g. 'am attach-agent').
extern "C" JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM* vm, char* options, void* reserved) {
return AgentStart(vm, options, reserved);
}
// Early attachment
extern "C" JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM* jvm, char* options, void* reserved) {
return AgentStart(jvm, options, reserved);
}
} // namespace dumpjvmti