libsysutils: Introduce 'ServiceManager', for starting/stopping init services

/*

 * Copyright (C) 2008 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.

 */

#ifndef _SERVICE_MANAGER_H

#define _SERVICE_MANAGER_H

class ServiceManager {

public:

    ServiceManager();

    virtual ~ServiceManager() {}

    int start(const char *name);

    int stop(const char *name);

    bool isRunning(const char *name);

};

#endif

                  src/NetlinkEvent.cpp        \

                  src/FrameworkCommand.cpp    \

                  src/SocketClient.cpp        \

                  src/ServiceManager.cpp      \

LOCAL_MODULE:= libsysutils

#include <errno.h>

#include <sysutils/ServiceManager.h>

#define LOG_TAG "Service"

#include <cutils/log.h>

#include <cutils/properties.h>

ServiceManager::ServiceManager() {

}

int ServiceManager::start(const char *name) {

    if (isRunning(name)) {

        LOGW("Service '%s' is already running", name);

        return 0;

    }

    LOGD("Starting service '%s'", name);

    property_set("ctl.start", name);

    int count = 200;

    while(count--) {

        sched_yield();

        if (isRunning(name))

            break;

    }

    if (!count) {

        LOGW("Timed out waiting for service '%s' to start", name);

        errno = ETIMEDOUT;

        return -1;

    }

    LOGD("Sucessfully started '%s'", name);

    return 0;

}

int ServiceManager::stop(const char *name) {

    if (!isRunning(name)) {

        LOGW("Service '%s' is already stopped", name);

        return 0;

    }

    LOGD("Stopping service '%s'", name);

    property_set("ctl.stop", name);

    int count = 200;

    while(count--) {

        sched_yield();

        if (!isRunning(name))

            break;

    }

    if (!count) {

        LOGW("Timed out waiting for service '%s' to stop", name);

        errno = ETIMEDOUT;

        return -1;

    }

    LOGD("Sucessfully stopped '%s'", name);

    return 0;

}

bool ServiceManager::isRunning(const char *name) {

    char propVal[PROPERTY_VALUE_MAX];

    char propName[255];

    snprintf(propName, sizeof(propVal), "init.svc.%s", name);

    if (property_get(propName, propVal, NULL)) {

        if (!strcmp(propVal, "running"))

            return true;

    }

    return false;

}