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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 "lmkd_service.h"
#include <errno.h>
#include <android-base/logging.h>
#include <liblmkd_utils.h>
#include "service_list.h"
namespace android {
namespace init {
enum LmkdRegistrationResult {
LMKD_REG_SUCCESS,
LMKD_CONN_FAILED,
LMKD_REG_FAILED,
};
static int lmkd_socket = -1;
static LmkdRegistrationResult RegisterProcess(uid_t uid, pid_t pid, int oom_score_adjust) {
// connect to lmkd if not already connected
if (lmkd_socket < 0) {
lmkd_socket = lmkd_connect();
if (lmkd_socket < 0) {
return LMKD_CONN_FAILED;
}
}
// register service with lmkd
struct lmk_procprio params;
params.pid = pid;
params.uid = uid;
params.oomadj = oom_score_adjust;
params.ptype = PROC_TYPE_SERVICE;
if (lmkd_register_proc(lmkd_socket, &params) != 0) {
// data transfer failed, reset the connection
close(lmkd_socket);
lmkd_socket = -1;
return LMKD_REG_FAILED;
}
return LMKD_REG_SUCCESS;
}
static bool UnregisterProcess(pid_t pid) {
if (lmkd_socket < 0) {
// no connection or it was lost, no need to unregister
return false;
}
// unregister service
struct lmk_procremove params;
params.pid = pid;
if (lmkd_unregister_proc(lmkd_socket, &params) != 0) {
// data transfer failed, reset the connection
close(lmkd_socket);
lmkd_socket = -1;
return false;
}
return true;
}
static void RegisterServices(pid_t exclude_pid) {
for (const auto& service : ServiceList::GetInstance()) {
auto svc = service.get();
if (svc->oom_score_adjust() != DEFAULT_OOM_SCORE_ADJUST) {
// skip if process is excluded or not yet forked (pid==0)
if (svc->pid() == exclude_pid || svc->pid() == 0) {
continue;
}
if (RegisterProcess(svc->uid(), svc->pid(), svc->oom_score_adjust()) !=
LMKD_REG_SUCCESS) {
// a failure here resets the connection, will retry during next registration
break;
}
}
}
}
void LmkdRegister(const std::string& name, uid_t uid, pid_t pid, int oom_score_adjust) {
bool new_connection = lmkd_socket == -1;
LmkdRegistrationResult result;
result = RegisterProcess(uid, pid, oom_score_adjust);
if (result == LMKD_REG_FAILED) {
// retry one time if connection to lmkd was lost
result = RegisterProcess(uid, pid, oom_score_adjust);
new_connection = result == LMKD_REG_SUCCESS;
}
switch (result) {
case LMKD_REG_SUCCESS:
// register existing services once new connection is established
if (new_connection) {
RegisterServices(pid);
}
break;
case LMKD_CONN_FAILED:
PLOG(ERROR) << "lmkd connection failed when " << name << " process got started";
break;
case LMKD_REG_FAILED:
PLOG(ERROR) << "lmkd failed to register " << name << " process";
break;
}
}
void LmkdUnregister(const std::string& name, pid_t pid) {
if (!UnregisterProcess(pid)) {
PLOG(ERROR) << "lmkd failed to unregister " << name << " process";
}
}
} // namespace init
} // namespace android