unix socket实现进程通信

「爱情、让人受尽委屈。」 2024-04-17 20:35 97阅读 0赞

抄一段使用unix socket client的c代码

#include <stdio.h>  
    #include <stddef.h>  
    #include <sys/stat.h>  
    #include <sys/socket.h>
    #include <sys/un.h>  
    #include <errno.h>  
    #include <string.h>  
      
    /* Create a client endpoint and connect to a server.   Returns fd if all OK, <0 on error. */  
    int unix_socket_conn(const char *servername)  
    {   
      int fd;   
      if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)    /* create a UNIX domain stream socket */   
      {  
        return(-1);  
      }  
      int len, rval;  
       struct sockaddr_un un;            
      memset(&un, 0, sizeof(un));            /* fill socket address structure with our address */  
      un.sun_family = AF_UNIX;   
      sprintf(un.sun_path, "scktmp%05d", getpid());   
      len = offsetof(struct sockaddr_un, sun_path) + strlen(un.sun_path);  
      unlink(un.sun_path);               /* in case it already exists */   
      if (bind(fd, (struct sockaddr *)&un, len) < 0)  
      {   
         rval=  -2;   
      }   
      else  
      {  
        /* fill socket address structure with server's address */  
          memset(&un, 0, sizeof(un));   
          un.sun_family = AF_UNIX;   
          strcpy(un.sun_path, servername);   
          len = offsetof(struct sockaddr_un, sun_path) + strlen(servername);   
          if (connect(fd, (struct sockaddr *)&un, len) < 0)   
          {  
              rval= -4;   
          }   
          else  
          {  
             return (fd);  
          }  
      }  
      int err;  
      err = errno;  
      close(fd);   
      errno = err;  
      return rval;      
    }  
       
     void unix_socket_close(int fd)  
     {  
        close(fd);       
     }  
      
      
    int main(void)  
    {   
      srand((int)time(0));  
      int connfd;   
      connfd = unix_socket_conn("foo.sock");  
      if(connfd<0)  
      {  
         printf("Error[%d] when connecting...",errno);  
         return 0;  
      }  
       printf("Begin to recv/send...\n");    
      int i,n,size;  
      char rvbuf[4096];  
      for(i=0;i<10;i++)  
      {  
    /* 
        //=========接收===================== 
        size = recv(connfd, rvbuf, 800, 0);   //MSG_DONTWAIT 
         if(size>=0) 
         { 
            printf("Recieved Data[%d]:%c...%c\n",size,rvbuf[0],rvbuf[size-1]); 
         } 
         if(size==-1) 
         { 
             printf("Error[%d] when recieving Data.\n",errno);    
                 break;      
         } 
             if(size < 800) break; 
    */  
        //=========发送======================  
    memset(rvbuf,'a',2048);  
             rvbuf[2047]='b';  
             size = send(connfd, rvbuf, 2048, 0);  
         if(size>=0)  
         {  
            printf("Data[%d] Sended:%c.\n",size,rvbuf[0]);  
         }  
         if(size==-1)  
         {  
            printf("Error[%d] when Sending Data:%s.\n",errno,strerror(errno));     
                break;        
         }  
             sleep(1);  
      }  
       unix_socket_close(connfd);  
       printf("Client exited.\n");      
     }

要运行在Android平台上的话，要生成可执行文件，下了cygwin和mingw都没搞定。查了查发现ndk完全可以解决：就只需要在Android.mk最后的BUILD模式改成BUILD\_EXECUTABLE就好，生成so文件的话模式是BUILD\_SHARED\_LIBRARY。  
touch一个foo.sock文件，然后先运行Server端，再运行Client则可以发送成功！

## java端 ##

[https://github.com/mcfunley/juds][https_github.com_mcfunley_juds]  
[https://github.com/jnr/jnr-unixsocket][https_github.com_jnr_jnr-unixsocket]  
[https://github.com/kohlschutter/junixsocket][https_github.com_kohlschutter_junixsocket]

java需要使用第三方库才能使用unix socket，这里我们使用的是第一个mcfunley/juds，因为它star竟高出第二名15个！！！嗯。  
unix socket分两种类型，一种类似TCP，叫做STREAM类型，一种类似UDP，叫做DGRAM类型。按自己的理解调用一下：

try {
                boolean result = new File("/mnt/sdcard/uds").createNewFile();
                Log.d(TAG, "create file result=" + result);
                final UnixDomainSocketClient streamClient = new UnixDomainSocketClient("/mnt/sdcard/uds", JUDS.SOCK_STREAM);
                final UnixDomainSocketServer streamServer = new UnixDomainSocketServer("/mnt/sdcard/uds", JUDS.SOCK_STREAM);
    
                new Thread(){
                    @Override
                    public void run() {
                        byte[] buf = new byte[128];
                        try {
                            int count = streamServer.getInputStream().read(buf);
                            Log.d(TAG, "size of data=" + count);
                            for(byte b : buf){
                                Log.d(TAG, "byte=" + b);
                            }
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }.start();
    
                new Thread(){
                    @Override
                    public void run() {
                        try {
                            streamClient.getOutputStream().write("Hello stm".getBytes());
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }.start();
    
            } catch (IOException e) {
                e.printStackTrace();
            }

2017-5-19  
java端与c端的通信报出java.io.IOException: Unable to write to Unix domain socket  
问题有待解决。

[https_github.com_mcfunley_juds]: https://link.jianshu.com/?t=https://github.com/mcfunley/juds
[https_github.com_jnr_jnr-unixsocket]: https://link.jianshu.com/?t=https://github.com/jnr/jnr-unixsocket
[https_github.com_kohlschutter_junixsocket]: https://link.jianshu.com/?t=https://github.com/kohlschutter/junixsocket