/*
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* Copyright (C) 2009-2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "Service"
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#include <errno.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/system_properties.h>
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#include <unistd.h>
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#include <android-base/properties.h>
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#include <android-base/stringprintf.h>
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#include <log/log.h>
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#include <sysutils/ServiceManager.h>
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ServiceManager::ServiceManager() {
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}
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// The length of a service name should not exceed SERVICE_NAME_MAX. Starting
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// a service is done by writing its name to the "ctl.start" system property
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// and stopping a service is done by writing its name to "ctl.stop". If a
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// service name is too long to fit in a property, you won't be able to start
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// or stop it.
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static constexpr size_t SERVICE_NAME_MAX = PROP_VALUE_MAX;
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/* The maximum amount of time to wait for a service to start or stop,
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* in micro-seconds (really an approximation) */
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#define SLEEP_MAX_USEC 2000000 /* 2 seconds */
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/* The minimal sleeping interval between checking for the service's state
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* when looping for SLEEP_MAX_USEC */
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#define SLEEP_MIN_USEC 200000 /* 200 msec */
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int ServiceManager::start(const char *name) {
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if (strlen(name) > SERVICE_NAME_MAX) {
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SLOGE("Service name '%s' is too long", name);
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return 0;
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}
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if (isRunning(name)) {
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SLOGW("Service '%s' is already running", name);
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return 0;
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}
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SLOGD("Starting service '%s'", name);
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android::base::SetProperty("ctl.start", name);
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int count = SLEEP_MAX_USEC;
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while(count > 0) {
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usleep(SLEEP_MIN_USEC);
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count -= SLEEP_MIN_USEC;
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if (isRunning(name))
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break;
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}
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if (count <= 0) {
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SLOGW("Timed out waiting for service '%s' to start", name);
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errno = ETIMEDOUT;
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return -1;
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}
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SLOGD("Sucessfully started '%s'", name);
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return 0;
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}
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int ServiceManager::stop(const char *name) {
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if (strlen(name) > SERVICE_NAME_MAX) {
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SLOGE("Service name '%s' is too long", name);
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return 0;
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}
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if (!isRunning(name)) {
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SLOGW("Service '%s' is already stopped", name);
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return 0;
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}
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SLOGD("Stopping service '%s'", name);
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android::base::SetProperty("ctl.stop", name);
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int count = SLEEP_MAX_USEC;
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while(count > 0) {
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usleep(SLEEP_MIN_USEC);
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count -= SLEEP_MIN_USEC;
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if (!isRunning(name))
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break;
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}
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if (count <= 0) {
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SLOGW("Timed out waiting for service '%s' to stop", name);
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errno = ETIMEDOUT;
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return -1;
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}
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SLOGD("Successfully stopped '%s'", name);
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return 0;
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}
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bool ServiceManager::isRunning(const char *name) {
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std::string property_name = android::base::StringPrintf("init.svc.%s", name);
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return (android::base::GetProperty(property_name, "") == "running");
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}
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