那些遇到过的问题

Android LocalServerSocket

Boh*_* Lu 11 java unix sockets java-native-interface android

在android中,有两个类LocalServerSocket和LocalSocket.我认为它们类似于unix socket中的AF_LOCAL(我不确定它是否正确).

我的问题是:是否可以在Java中创建LocalServerSocket并使用普通的unix套接字客户端在本机或其他进程中连接到它？

如果有可能,我应该在本机中设置"sockaddr_un.sun_path"是什么？

我编写了一个示例项目来测试它,我尝试将.sun_path设置为与LocalServerSocket中使用的字符串名称相同,但是它失败了,本机无法连接到Java LocalServerSocket.

我的Java代码:

package test.socket;

import java.io.IOException;
import java.io.InputStream;

import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.content.Intent;
import android.net.LocalServerSocket;
import android.net.LocalSocket;
import android.os.Bundle;
import android.util.Log;
import android.view.View;

public class TestSocketActivity extends Activity {

    public static String SOCKET_ADDRESS = "my.local.socket.address";
    public String TAG = "Socket_Test";


    static{System.loadLibrary("testSocket");}
    private native void clientSocketThreadNative();
    private native void setStopThreadNative();
    localServerSocket mLocalServerSocket;
    localClientSocket mLocalClientSocket;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mLocalServerSocket = new localServerSocket();

        mLocalClientSocket = new localClientSocket();
    }

    /* LocalServerSocket */
    public class localServerSocket extends Thread {

        int bufferSize = 32;
        byte[] buffer;
        int bytesRead;
        int totalBytesRead;
        int posOffset;
        LocalServerSocket server;
        LocalSocket receiver;
        InputStream input;
        private volatile boolean stopThread;

        public localServerSocket() {
            Log.d(TAG, " +++ Begin of localServerSocket() +++ ");
            buffer = new byte[bufferSize];
            bytesRead = 0;
            totalBytesRead = 0;
            posOffset = 0;

            try {
                server = new LocalServerSocket(SOCKET_ADDRESS);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                Log.d(TAG, "The LocalServerSocket created failed !!!");
                e.printStackTrace();
            }

            stopThread = false;
        }

        public void run() {             
            Log.d(TAG, " +++ Begin of run() +++ ");
                while (!stopThread) {

                    if (null == server){
                        Log.d(TAG, "The LocalServerSocket is NULL !!!");
                        stopThread = true;
                        break;
                    }

                    try {
                        Log.d(TAG, "LocalServerSocket begins to accept()");
                        receiver = server.accept();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        Log.d(TAG, "LocalServerSocket accept() failed !!!");
                        e.printStackTrace();
                        continue;
                    }                   

                    try {
                        input = receiver.getInputStream();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        Log.d(TAG, "getInputStream() failed !!!");
                        e.printStackTrace();
                        continue;
                    }

                    Log.d(TAG, "The client connect to LocalServerSocket");

                    while (receiver != null) {

                        try {
                            bytesRead = input.read(buffer, posOffset,
                                    (bufferSize - totalBytesRead));
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            Log.d(TAG, "There is an exception when reading socket");
                            e.printStackTrace();
                            break;
                        }

                        if (bytesRead >= 0) {
                            Log.d(TAG, "Receive data from socket, bytesRead = "
                                    + bytesRead);
                            posOffset += bytesRead;
                            totalBytesRead += bytesRead;
                        }

                        if (totalBytesRead == bufferSize) {
                            Log.d(TAG, "The buffer is full !!!");
                            String str = new String(buffer);
                            Log.d(TAG, "The context of buffer is : " + str);

                            bytesRead = 0;
                            totalBytesRead = 0;
                            posOffset = 0;
                        }

                    }
                    Log.d(TAG, "The client socket is NULL !!!");
                }
                Log.d(TAG, "The LocalSocketServer thread is going to stop !!!");
                if (receiver != null){
                    try {
                        receiver.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
                if (server != null){
                    try {
                        server.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
        }

        public void setStopThread(boolean value){
            stopThread = value;
            Thread.currentThread().interrupt(); // TODO : Check
        }

    }




    /* Client native socket */
    public class localClientSocket extends Thread {

        private volatile boolean stopThread;

        public localClientSocket(){
            Log.d(TAG, " +++ Begin of localClientSocket() +++ ");
            stopThread = false;
        }

        public void run(){
            Log.d(TAG, " +++ Begin of run() +++ ");
            while(!stopThread){
                clientSocketThreadNative();
            }
        }

        public void setStopThread(boolean value){
            stopThread = value;
            setStopThreadNative();
            Thread.currentThread().interrupt(); // TODO : Check
        }
    }


    public void bt_startServerOnClick(View v) {
        mLocalServerSocket.start();
    }

    public void bt_startClientOnClick(View v) {
        mLocalClientSocket.start();
    }

    public void bt_stopOnClick(View v) {
        mLocalClientSocket.setStopThread(true);
        mLocalServerSocket.setStopThread(true);
    }

}
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我的原生代码:

#define SOCKET_NAME "my.local.socket.address"

JNIEXPORT void JNICALL Java_test_socket_TestSocketActivity_clientSocketThreadNative
  (JNIEnv *env, jobject object){

    LOGD("In clientSocketThreadNative() : Begin");

    stopThread = 1;

    int sk, result;
    int count = 1;
    int err;

    char *buffer = malloc(8);

    int i;
    for(i = 0; i<8; i++){
        buffer[i] = (i+1);
    }

    /*
    struct sockaddr_un addr;

    bzero((char *)&addr,sizeof(addr);
    addr.sun_family = AF_UNIX;
    addr.sun_path = SOCKET_NAME;
    */

    struct sockaddr_un addr = {
        AF_UNIX, SOCKET_NAME
    };

    LOGD("In clientSocketThreadNative() : Before creating socket");
    sk = socket(PF_LOCAL, SOCK_STREAM, 0);

    if (sk < 0) {
        err = errno;
        LOGD("%s: Cannot open socket: %s (%d)\n",
            __FUNCTION__, strerror(err), err);
        errno = err;
        return;
    }

    LOGD("In clientSocketThreadNative() : Before connecting to Java LocalSocketServer");
    if (connect(sk, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
        err = errno;
        LOGD("%s: connect() failed: %s (%d)\n",
            __FUNCTION__, strerror(err), err);
        close(sk);
        errno = err;
        return;
    }

    LOGD("In clientSocketThreadNative() : Connecting to Java LocalSocketServer succeed");

    while(!stopThread){
        result = write(sk, buffer, 8);
        LOGD("In clientSocketThreadNative() : Total write = %d", result);
        count++;
        if(4 == count){
            sleep(1);
            count = 0;
        } 
    }

    LOGD("In clientSocketThreadNative() : End");
}
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任何建议将不胜感激!!!

Boh*_* Lu 12

以下代码可能不完美,但它的工作原理!谢谢迈克.

Java部分(套接字服务器): 

package test.socket;

import java.io.IOException;
import java.io.InputStream;

import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.content.Intent;
import android.net.LocalServerSocket;
import android.net.LocalSocket;
import android.net.LocalSocketAddress;
import android.os.Bundle;
import android.util.Log;
import android.view.View;

public class TestSocketActivity extends Activity {

    public static String SOCKET_ADDRESS = "/test/socket/localServer";
    public String TAG = "Socket_Test";


    static{System.loadLibrary("testSocket");}
    private native void clientSocketThreadNative();
    private native void setStopThreadNative();
    localSocketServer mLocalSocketServer;
    localSocketClient mLocalSocketClient;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        mLocalSocketServer = new localSocketServer();

        mLocalSocketClient = new localSocketClient();
    }

    /* LocalSocketServer */
    public class localSocketServer extends Thread {

        int bufferSize = 32;
        byte[] buffer;
        int bytesRead;
        int totalBytesRead;
        int posOffset;
        LocalServerSocket server;
        LocalSocket receiver;
        InputStream input;
        private volatile boolean stopThread;

        public localSocketServer() {
            Log.d(TAG, " +++ Begin of localSocketServer() +++ ");
            buffer = new byte[bufferSize];
            bytesRead = 0;
            totalBytesRead = 0;
            posOffset = 0;

            try {
                server = new LocalServerSocket(SOCKET_ADDRESS);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                Log.d(TAG, "The localSocketServer created failed !!!");
                e.printStackTrace();
            }

             LocalSocketAddress localSocketAddress; 
             localSocketAddress = server.getLocalSocketAddress();
             String str = localSocketAddress.getName();

             Log.d(TAG, "The LocalSocketAddress = " + str);

            stopThread = false;
        }

        public void run() {             
            Log.d(TAG, " +++ Begin of run() +++ ");
                while (!stopThread) {

                    if (null == server){
                        Log.d(TAG, "The localSocketServer is NULL !!!");
                        stopThread = true;
                        break;
                    }

                    try {
                        Log.d(TAG, "localSocketServer begins to accept()");
                        receiver = server.accept();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        Log.d(TAG, "localSocketServer accept() failed !!!");
                        e.printStackTrace();
                        continue;
                    }                   

                    try {
                        input = receiver.getInputStream();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        Log.d(TAG, "getInputStream() failed !!!");
                        e.printStackTrace();
                        continue;
                    }

                    Log.d(TAG, "The client connect to LocalServerSocket");

                    while (receiver != null) {

                        try {
                            bytesRead = input.read(buffer, posOffset,
                                    (bufferSize - totalBytesRead));
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            Log.d(TAG, "There is an exception when reading socket");
                            e.printStackTrace();
                            break;
                        }

                        if (bytesRead >= 0) {
                            Log.d(TAG, "Receive data from socket, bytesRead = "
                                    + bytesRead);
                            posOffset += bytesRead;
                            totalBytesRead += bytesRead;
                        }

                        if (totalBytesRead == bufferSize) {
                            Log.d(TAG, "The buffer is full !!!");
                            String str = new String(buffer);
                            Log.d(TAG, "The context of buffer is : " + str);

                            bytesRead = 0;
                            totalBytesRead = 0;
                            posOffset = 0;
                        }

                    }
                    Log.d(TAG, "The client socket is NULL !!!");
                }
                Log.d(TAG, "The LocalSocketServer thread is going to stop !!!");
                if (receiver != null){
                    try {
                        receiver.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
                if (server != null){
                    try {
                        server.close();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
        }

        public void setStopThread(boolean value){
            stopThread = value;
            Thread.currentThread().interrupt(); // TODO : Check
        }

    }

    /* Client native socket */
    public class localSocketClient extends Thread {

        private volatile boolean stopThread;

        public localSocketClient(){
            Log.d(TAG, " +++ Begin of localSocketClient() +++ ");
            stopThread = false;
        }

        public void run(){
            Log.d(TAG, " +++ Begin of run() +++ ");
            while(!stopThread){
                clientSocketThreadNative();
            }
        }

        public void setStopThread(boolean value){
            stopThread = value;
            setStopThreadNative();
            Thread.currentThread().interrupt(); // TODO : Check
        }
    }


    public void bt_startServerOnClick(View v) {
        mLocalSocketServer.start();
    }

    public void bt_startClientOnClick(View v) {
        mLocalSocketClient.start();
    }

    public void bt_stopOnClick(View v) {
        mLocalSocketClient.setStopThread(true);
        mLocalSocketServer.setStopThread(true);
    }

}
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原生C部分(客户端)

#include <stdlib.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/un.h>


#include "test_socket_TestSocketActivity.h"

#define LOCAL_SOCKET_SERVER_NAME "/test/socket/localServer"

volatile int stopThread;

#ifndef __JNILOGGER_H_
#define __JNILOGGER_H_ 
#include <android/log.h> 
#ifdef __cplusplus
extern "C" {
#endif
#ifndef LOG_TAG
#define LOG_TAG "NativeSocket"
#endif
#define LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,__VA_ARGS__)
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)
#define LOGW(...) __android_log_print(ANDROID_LOG_WARN,LOG_TAG,__VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
#define LOGF(...) __android_log_print(ANDROID_LOG_FATAL,LOG_TAG,__VA_ARGS__)
#define LOGS(...) __android_log_print(ANDROID_LOG_SILENT,LOG_TAG,__VA_ARGS__)
#define LOGV(...) __android_log_print(ANDROID_LOG_VERBOSE,LOG_TAG,__VA_ARGS__)
#ifdef __cplusplus
}
#endif
#endif /* __JNILOGGER_H_ */ 


JNIEXPORT void JNICALL Java_test_socket_TestSocketActivity_clientSocketThreadNative
  (JNIEnv *env, jobject object){

    LOGD("In clientSocketThreadNative() : Begin");

    stopThread = 0;

    int sk, result;
    int count = 1;
    int err;

    char *buffer = malloc(8);

    int i;
    for(i = 0; i<8; i++){
        buffer[i] = (i+1);
    }

    struct sockaddr_un addr;
    socklen_t len;
    addr.sun_family = AF_LOCAL;
    /* use abstract namespace for socket path */
    addr.sun_path[0] = '\0';
    strcpy(&addr.sun_path[1], LOCAL_SOCKET_SERVER_NAME );
    len = offsetof(struct sockaddr_un, sun_path) + 1 + strlen(&addr.sun_path[1]);

    LOGD("In clientSocketThreadNative() : Before creating socket");
    sk = socket(PF_LOCAL, SOCK_STREAM, 0);
    if (sk < 0) {
        err = errno;
        LOGD("%s: Cannot open socket: %s (%d)\n",
            __FUNCTION__, strerror(err), err);
        errno = err;
        return;
    }

    LOGD("In clientSocketThreadNative() : Before connecting to Java LocalSocketServer");
    if (connect(sk, (struct sockaddr *) &addr, len) < 0) {
        err = errno;
        LOGD("%s: connect() failed: %s (%d)\n",
            __FUNCTION__, strerror(err), err);
        close(sk);
        errno = err;
        return;
    }

    LOGD("In clientSocketThreadNative() : Connecting to Java LocalSocketServer succeed");
    while(!stopThread){
        result = write(sk, buffer, 8);
        LOGD("In clientSocketThreadNative() : Total write = %d", result);
        count++;
        if(4 == count){
            sleep(1);
            count = 0;
        } 
    }


    LOGD("In clientSocketThreadNative() : End");
}


JNIEXPORT void JNICALL Java_test_socket_TestSocketActivity_setStopThreadNative
  (JNIEnv *env, jobject object){

    stopThread = 1;

}
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mpo*_*llo 4

查看local_socket_client.cAndroid 源代码，看起来他们是这样做的：

int socket_make_sockaddr_un(const char *name, int namespaceId, 
        struct sockaddr_un *p_addr, socklen_t *alen)
{
    memset (p_addr, 0, sizeof (*p_addr));
    size_t namelen;

    switch (namespaceId) {
        case ANDROID_SOCKET_NAMESPACE_ABSTRACT:
            namelen  = strlen(name);

            // Test with length +1 for the *initial* '\0'.
            if ((namelen + 1) > sizeof(p_addr->sun_path)) {
                goto error;
            }

            /*
             * Note: The path in this case is *not* supposed to be
             * '\0'-terminated. ("man 7 unix" for the gory details.)
             */

            p_addr->sun_path[0] = 0;
            memcpy(p_addr->sun_path + 1, name, namelen);

            ...
    p_addr->sun_family = AF_LOCAL;
    *alen = namelen + offsetof(struct sockaddr_un, sun_path) + 1;
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看来 memset() 很重要，因为整个sun_path都是相关的。（不过，看起来你用结构初始化覆盖了该部分。）它不是“0”加上原始名称，它是一个实际的零字节！（它的值都是二进制零，而不是 ascii '0'）

尝试更密切地关注他们正在做的事情，包括前导“\0”字节和 AF_LOCAL 系列。

如果您更新了代码（无论是否有效），请发布！我对你的结果很感兴趣。你曾经让它发挥作用吗？

如果它不起作用，请找出它errno是什么，然后调用perror()将其打印到stderr，或者调用strerror()并记录输出。让我们知道您遇到了什么错误。

编辑

我最近在自己的一个项目中解决了这个问题。我发现关键是调用connect()and时指定正确的长度bind()。在我上面发布的代码中，它通过使用sun_path结构中的偏移量加上名称的长度以及前导'\0'字节加一来计算长度。如果指定任何其他长度，Java 代码可能无法连接到套接字。

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