server_fork.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

#define SERVER_ADDR "127.0.0.1"
#define SERVER_PORT 3333
#define BACKLOG 5

void handle_read(int confd);

int main()
{
 int fd, confd, sockfd;
 struct sockaddr_in addr;
 struct sockaddr_in cli_addr;
 socklen_t cli_addr_len;
 pid_t pid;

 memset(&addr, 0, sizeof(addr));
 memset(&cli_addr, 0, sizeof(cli_addr));

 addr.sin_family = AF_INET;
 addr.sin_addr.s_addr = inet_addr(SERVER_ADDR);
 addr.sin_port = htons(SERVER_PORT);
 
 if( (fd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
  printf("error to create the socket\n");
  exit(-1);
 }


 if(bind(fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
  printf("error to bind the socket\n");
  exit(-2);
 }
 
 if(listen(fd, BACKLOG) == -1) {
  printf("error to listen the socket\n");
  exit(-3);
 }

 while(1) {
  confd = accept(fd, NULL, NULL);

  //child
  if( (pid = fork()) == 0) {
   close(fd);
   handle_read(confd);
   close(confd);
   exit(0);
  }

  close(confd);
 }
}

void handle_read(int confd)
{
 char buf[16];
 int num = 0;

 while( (num = read(confd, buf, 15)) > 0) {
  buf[num] = '\0';
  printf("%s\n", buf);
 }

 if(num == 0) {
  printf("client close the connection\n");
 }
 else if(num < 0) {
  printf("connection error\n");
 }
}