platform_system_core/init/lmkd_service.cpp
Suren Baghdasaryan c29c2baa69 init: Add support for native service registration with lmkd
init should be able to register native services with lmkd so that they
can be killed when needed. Only processes with oom_score_adjust not
equal to the default -1000 will be registered with lmkd because with the
score that low the process is unkillable anyway.
Inform lmkd when a registered process is killed so that the record can be
removed.
Change init.rc to start lmkd during init phase so that it is there to
register other services.
Replace hardcoded oom_score_adj values with appropriate definitions.

Bug: 129011369
Test: boot and verify native service registration
Change-Id: Ie5ed62203395120d86dc1c8250fae01aa0b3c511
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
2019-11-07 18:19:31 +00:00

131 lines
3.8 KiB
C++

/*
* 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().services()) {
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