linux进程间通信--socket套接字

  SOCKET是进程间通信的一种方式，这个时候socket的创建、绑定、连接时的参数是与网络上不同主机间的通信不同的，比如对于socketaddr的使用，进程间通信使用的是sockaddr_un。而主机间的通信使用的是sockadd_in。

  现贴出简单的未使用线程的进程间通信代码：

  server端：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#define UNIX_DOMAIN "/tmp/UNIX.domain"

int main(void)
{
  int lsn_fd, apt_fd;
  struct sockaddr_un srv_addr;
  struct sockaddr_un clt_addr;
  socklen_t clt_len;
  int ret;
  int i;
  char recv_buf[1024];
  char send_buf[1024];

  //create socket to bind local IP and PORT
  lsn_fd = socket(PF_UNIX, SOCK_STREAM, 0);
  if(lsn_fd < 0)
  {
    perror("can't create communication socket!");
    return 1;
  }

  //create local IP and PORT
  srv_addr.sun_family = AF_UNIX;
  strncpy(srv_addr.sun_path, UNIX_DOMAIN, sizeof(srv_addr.sun_path) - 1);
  unlink(UNIX_DOMAIN);

  //bind sockfd and sockaddr
  ret = bind(lsn_fd, (struct sockaddr*)&srv_addr, sizeof(srv_addr));
  if(ret == -1)
  {
    perror("can't bind local sockaddr!");
    close(lsn_fd);
    unlink(UNIX_DOMAIN);
    return 1;
  }

  //listen lsn_fd, try listen 1
  ret = listen(lsn_fd, 1);
  if(ret == -1)
  {
    perror("can't listen client connect request");
    close(lsn_fd);
    unlink(UNIX_DOMAIN);
    return 1;
  }

  clt_len = sizeof(clt_addr);
  while(1)
  {
    apt_fd = accept(lsn_fd, (struct sockaddr*)&clt_addr, &clt_len);
    if(apt_fd < 0)
    {
      perror("can't listen client connect request");
      close(lsn_fd);
      unlink(UNIX_DOMAIN);
      return 1;
    }

    printf("received a connection\n");
    printf("send message to client\n");
    memset(send_buf, 0, 1024);
    strcpy(send_buf, "Hello, you have connected to server succeed");

    int snd_num = write(apt_fd, send_buf, 1024);
    if(snd_num != 1024)
    {
      perror("send messge to client failed\n");
      close(apt_fd);
      close(lsn_fd);
      unlink(UNIX_DOMAIN);
      return 1;
    }
    //read and printf client info
    printf("============info=================\n");
    for(i = 0; i < 4; i++)
    {
      memset(recv_buf, 0, 1024);
      int rcv_num = read(apt_fd, recv_buf, sizeof(recv_buf));
      printf("Message from client (%d) :%s\n", rcv_num, recv_buf);
    }
  }
  close(apt_fd);
  close(lsn_fd);
  unlink(UNIX_DOMAIN);
  return 0;
}

client端：

#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#define UNIX_DOMAIN "/tmp/UNIX.domain"

int main(void)
{
  int connect_fd;
  struct sockaddr_un srv_addr;
  char snd_buf[1024];
  char rcv_buf[1024];
  int ret;
  int i;

  //create client socket
  connect_fd = socket(PF_UNIX, SOCK_STREAM, 0);
  if(connect_fd < 0)
  {
    perror("client create socket failed");
    return 1;
  }

  //set server sockaddr_un
  srv_addr.sun_family = AF_UNIX;
  strcpy(srv_addr.sun_path, UNIX_DOMAIN);

  //connect to server
  ret = connect(connect_fd, (struct sockaddr*)&srv_addr, sizeof(srv_addr));
  if(ret == -1)
  {
    perror("connect to server failed!");
    close(connect_fd);
    unlink(UNIX_DOMAIN);
    return 1;
  }

  //receive message from server
  memset(rcv_buf, 0, 1024);
  int rcv_num = read(connect_fd, rcv_buf, sizeof(rcv_buf));
  printf("receive message from server (%d) :%s\n", rcv_num, rcv_buf);
  //printf("\n");

  //send message to server
  memset(snd_buf, 0, 1024);
  strcpy(snd_buf, "message from client");
  printf("sizeof(snd_buf): %d\n", sizeof(snd_buf));
  sleep(2000);

  //send message to server
  for(i = 0; i < 4; i++)
  {
    write(connect_fd, snd_buf, sizeof(snd_buf));
  }
  close(connect_fd);
  return 0;
}

批注：如果想要实现多个客户端的登录，可以书写一个shell脚本，进行批处理连接。