android控制台应用binder通讯

在android root环境下,有一个后台服务server进程需要提供接口给控制台应用client调用,本来想用socket方式来做的,后台发现android有更高效的方式来实现.那就是binder.

查了一下资料,具体的binder驱动的实现细节比较复杂,网上一堆教程都是先aidl，再生成代码，

其实不用那么复杂，下面应该是最简单写法了。

server

#include <binder/IServiceManager.h>

#include <binder/IPCThreadState.h>

#include <binder/IInterface.h>

#include <binder/Parcel.h>

#include <utils/Errors.h>

#include <pthread>

using namespace android;

//客户端回调引用

sp<IBinder> clientCallback;

enum {

    code_test_hello = 1,

    code_test_callback_registe = 2

}

enum {

    cb_code_test = 1

}

void callback_test(const char* params) {

    if (clientCallback == NULL) { \

        LOGD("%s clientCallback == null", __FUNCTION__);

        return;

    }

    if (!clientCallback->isBinderAlive()){

         LOGD("%s clientCallback not alive", __FUNCTION__);

        return;

     }

    int32_t t =  clientCallback->pingBinder();

    bool b = clientCallback->isBinderAlive();

    Parcel request, reply;

    request.writeCString(params);

    clientCallback->transact(EnumCallback::cb_code_test, request, &reply);

}

class ServiceService: public BBinder {

public:

    ServiceService();

    virtual status_t onTransact(uint32_t code, const Parcel&, Parcel*, uint32_t){

        switch(code) {

            case code_test_hello:

            {

                printf("from client:%s", request.readCString());

                reply->writeCString("hello client");

                return NO_ERROR;

            }

            case code_test_callback_registe:

            {

                clientCallback = request.readStrongBinder();

                reply->writeInt32(0);

                return NO_ERROR;

            }

        }

        return BBinder::onTransact(code, request, reply, flag);

    }

};

void *binderThread (void *arg){

    sp<ProcessState> proc(ProcessState::self());

    defaultServiceManager()->addService(String16("ServiceService"), new ServiceService());

    ProcessState::self()->startThreadPool();

    IPCThreadState::self()->joinThreadPool();

    return ((void *)0);

}

int initBinderPool() {

    return pthread_create(NULL, NULL, binderThread, NULL);

}

int main(int argc, char *argv[]) {

    //启动binder框架线程池

    initBinderPool();

    while(true) {

        callback_test("hello word");

        sleep(1);

    }

    return 0;

}

client

#include <binder/IServiceManager.h>

#include <binder/IPCThreadState.h>

#include <binder/Parcel.h>

#include <utils/Errors.h>

#include <stdio.h>

#include <binder/IMemory.h>

#include <binder/MemoryHeapBase.h>

#include <binder/MemoryBase.h>

#include <android/log.h>

#define TAG "bindertest"

#define LOGD(...) \

printf(__VA_ARGS__); \

__android_log_print(ANDROID_LOG_ERROR, TAG, __VA_ARGS__)

using namespace android;

static sp<IBinder> service;

enum {

    code_test_hello = 1,

    code_test_callback_registe = 2

}

enum {

    cb_code_test = 1

}

class Callback : public BBinder {

    public:

    status_t onTransact(uint32_t code, const Parcel &request, Parcel *reply, uint32_t flag) {

        switch (code) {

            case cb_code_test:{

                const char* str = request.readCString();

                LOGD("msg from server cb:%s\n", str);

                reply->writeInt32(0);

                break;

            }

        }

        return BBinder::onTransact(code, request, reply, flag);

    }

};

static void callback_connect(const sp<Callback>& callback) {

    if (service == NULL) {

        LOGD("[%s] service not init", __FUNCTION__);

        return ret;

    }

    Parcel request, reply;

    request.writeStrongBinder(callback);

    service->transact(CMD_CALLBACK_INIT, request, &reply);

}

void* binderThread(void* params){

    sp<ProcessState> proc(ProcessState::self());

    ProcessState::self()->startThreadPool();

    IPCThreadState::self()->joinThreadPool();

    return NULL;

}

void testHello() {

    if (service == NULL) {

        LOGD("[%s] service not init", __FUNCTION__);

        return ret;

    }

    Parcel request, reply;

    request.writeCString("hello server");

    service->transact(code_test_hello, request, &reply);

    printf("from server:%s", reply.readCString());

}

int main(int argc, char *argv[]) {

    sp<ProcessState> proc(ProcessState::self());

    service = defaultServiceManager()->getService(String16("ServiceService"));

    if (!service) {

        LOGD("get ServiceService fail");

        return 0;

    }

    //注册回调

    sp<Callback> callback = new Callback();

    callback_connect(callback);

    //启动binder线程池，不启动的话，server端的回调会卡住

    pthread_create(NULL, NULL, binderThread,NULL);

    while(true) {

        testHello();

        sleep(1);

    }

    return 0;

}

参考

http://qiushao.net/2019/12/29/Android%E7%B3%BB%E7%BB%9F%E5%BC%80%E5%8F%91%E5%85%A5%E9%97%A8/9-%E6%B7%BB%E5%8A%A0native%E7%B3%BB%E7%BB%9F%E6%9C%8D%E5%8A%A1/

巴特西

android控制台应用binder通讯

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