//s_unix.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h> 
#define UNIX_DOMAIN "/tmp/UNIX.domain"
int main(void)
{
  socklen_t clt_addr_len;
  int listen_fd;
  int com_fd;
  int ret;
  int i;
  static char recv_buf[1024]; 
  int len;
  struct sockaddr_un clt_addr;
  struct sockaddr_un srv_addr;
  listen_fd=socket(PF_UNIX,SOCK_STREAM,0);
  if(listen_fd<0)
  {
    perror("cannot create communication socket");
    return 1;
  } 

  //set server addr_param
  srv_addr.sun_family=AF_UNIX;
  strncpy(srv_addr.sun_path,UNIX_DOMAIN,sizeof(srv_addr.sun_path)-1);
  unlink(UNIX_DOMAIN);
  //bind sockfd & addr
  ret=bind(listen_fd,(struct sockaddr*)&srv_addr,sizeof(srv_addr));
  if(ret==-1)
  {
    perror("cannot bind server socket");
    close(listen_fd);
    unlink(UNIX_DOMAIN);
    return 1;
  }
  //listen sockfd 
  ret=listen(listen_fd,1);
  if(ret==-1)
  {
    perror("cannot listen the client connect request");
    close(listen_fd);
    unlink(UNIX_DOMAIN);
    return 1;
  }
  //have connect request use accept
  len=sizeof(clt_addr);
  com_fd=accept(listen_fd,(struct sockaddr*)&clt_addr,&len);
  if(com_fd<0)
  {
    perror("cannot accept client connect request");
    close(listen_fd);
    unlink(UNIX_DOMAIN);
    return 1;
  }
  //read and printf sent client info
  printf("/n=====info=====/n");
  for(i=0;i<4;i++)
  {
    memset(recv_buf,0,1024);
    int num=read(com_fd,recv_buf,sizeof(recv_buf));
    printf("Message from client (%d)) :%s/n",num,recv_buf); 
  }
  close(com_fd);
  close(listen_fd);
  unlink(UNIX_DOMAIN);
  return 0;
}

//c_unix.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#define UNIX_DOMAIN "/tmp/UNIX.domain"
int main(void)
{
  int connect_fd;
  int ret;
  char snd_buf[1024];
  int i;
  static struct sockaddr_un srv_addr;
//creat unix socket
  connect_fd=socket(PF_UNIX,SOCK_STREAM,0);
  if(connect_fd<0)
  {
    perror("cannot create communication socket");
    return 1;
  }  
  srv_addr.sun_family=AF_UNIX;
  strcpy(srv_addr.sun_path,UNIX_DOMAIN);
//connect server
  ret=connect(connect_fd,(struct sockaddr*)&srv_addr,sizeof(srv_addr));
  if(ret==-1)
  {
    perror("cannot connect to the server");
    close(connect_fd);
    return 1;
  }
  memset(snd_buf,0,1024);
  strcpy(snd_buf,"message from client");
//send info server
  for(i=0;i<4;i++)
    write(connect_fd,snd_buf,sizeof(snd_buf));
  close(connect_fd);
  return 0;
}