socket_server.c

Linux大学上机源码学习

#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <netinet/in.h>
#include <signal.h>
void doit(int);
int make_socket(unsigned short int port)
{
  int sock;
  struct sockaddr_in name;
  sock=socket(AF_INET,SOCK_STREAM,0);
  if(sock<0){
     printf("error is:%s",strerror(errno));
     exit(0);
  }
  name.sin_family=AF_INET;
  name.sin_port=htons(port);
  name.sin_addr.s_addr=htonl(INADDR_ANY);
  if(bind(sock,(struct sockaddr *)&name,sizeof(name))<0){
     printf("error is:%s",strerror(errno));
     exit(0);
  }
 return sock;
} 
int main(void)
{
  int server_sockfd,client_sockfd;
  int server_len,client_len;
  struct sockaddr_in client_address;
  server_sockfd=make_socket(2003);
  listen(server_sockfd,5);
  signal(SIGCHLD,SIG_IGN);
  while(1){
    printf("server waiting\n");
    client_len=sizeof(client_address);
    client_sockfd=accept(server_sockfd,(struct sockaddr *)&client_address,&client_len);
    if(fork()==0){
      close(server_sockfd);
      doit(client_sockfd);
      close(client_sockfd);
      exit(0);
    }
    else
      close(client_sockfd);
}
}
void doit(client_sockfd)
{
  char buf[255];
  int n;
  n=read(client_sockfd,buf,sizeof(buf));
  sleep(5);
  buf[n]=0;
  write(client_sockfd,buf,n);
}