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/*
* Copyright (C) 2023 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.
*/
#define LOG_TAG "OomConnection"
#include <core_jni_helpers.h>
#include <jni.h>
#include <memevents/memevents.h>
namespace android {
using namespace ::android::bpf::memevents;
// Used to cache the results of the JNI name lookup
static struct {
jclass clazz;
jmethodID ctor;
} sOomKillRecordInfo;
static MemEventListener memevent_listener(MemEventClient::AMS);
/**
* Initialize listening and waiting for new out-of-memory (OOM) events to occur.
* Once a OOM event is detected, we then fetch the list of OOM kills, and return
* a corresponding java array with the information gathered.
*
* In the case that we encounter an error, we make sure to close the epfd, and
* the OOM file descriptor, by calling `deregisterAllEvents()`.
*
* @return list of `android.os.OomKillRecord`
* @throws java.lang.RuntimeException
*/
static jobjectArray android_server_am_OomConnection_waitOom(JNIEnv* env, jobject) {
if (!memevent_listener.registerEvent(MEM_EVENT_OOM_KILL)) {
memevent_listener.deregisterAllEvents();
jniThrowRuntimeException(env, "listener failed to register to OOM events");
return nullptr;
}
if (!memevent_listener.listen()) {
memevent_listener.deregisterAllEvents();
jniThrowRuntimeException(env, "listener failed waiting for OOM event");
return nullptr;
}
std::vector<mem_event_t> oom_events;
if (!memevent_listener.getMemEvents(oom_events)) {
memevent_listener.deregisterAllEvents();
jniThrowRuntimeException(env, "Failed to get OOM events");
return nullptr;
}
jobjectArray java_oom_array =
env->NewObjectArray(oom_events.size(), sOomKillRecordInfo.clazz, nullptr);
if (java_oom_array == NULL) {
memevent_listener.deregisterAllEvents();
jniThrowRuntimeException(env, "Failed to create OomKillRecord array");
return nullptr;
}
for (int i = 0; i < oom_events.size(); i++) {
const mem_event_t mem_event = oom_events[i];
if (mem_event.type != MEM_EVENT_OOM_KILL) {
memevent_listener.deregisterAllEvents();
jniThrowRuntimeException(env, "Received invalid memory event");
return java_oom_array;
}
const auto oom_kill = mem_event.event_data.oom_kill;
jstring process_name = env->NewStringUTF(oom_kill.process_name);
if (process_name == NULL) {
memevent_listener.deregisterAllEvents();
jniThrowRuntimeException(env, "Failed creating java string for process name");
}
jobject java_oom_kill = env->NewObject(sOomKillRecordInfo.clazz, sOomKillRecordInfo.ctor,
oom_kill.timestamp_ms, oom_kill.pid, oom_kill.uid,
process_name, oom_kill.oom_score_adj);
if (java_oom_kill == NULL) {
memevent_listener.deregisterAllEvents();
jniThrowRuntimeException(env, "Failed to create OomKillRecord object");
return java_oom_array;
}
env->SetObjectArrayElement(java_oom_array, i, java_oom_kill);
}
return java_oom_array;
}
static const JNINativeMethod sOomConnectionMethods[] = {
/* name, signature, funcPtr */
{"waitOom", "()[Landroid/os/OomKillRecord;",
(void*)android_server_am_OomConnection_waitOom},
};
int register_android_server_am_OomConnection(JNIEnv* env) {
sOomKillRecordInfo.clazz = FindClassOrDie(env, "android/os/OomKillRecord");
sOomKillRecordInfo.clazz = MakeGlobalRefOrDie(env, sOomKillRecordInfo.clazz);
sOomKillRecordInfo.ctor =
GetMethodIDOrDie(env, sOomKillRecordInfo.clazz, "<init>", "(JIILjava/lang/String;S)V");
return RegisterMethodsOrDie(env, "com/android/server/am/OomConnection", sOomConnectionMethods,
NELEM(sOomConnectionMethods));
}
} // namespace android
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