week12_network, select server

select_server.c

/*
pineoc, 2015-05-18
week 12 network programming
select echo server
server code
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <sys/time.h>

#define BUF_SIZE 100
void error_handling(char* msg);

int main(int argc,char* argv[])
{
	int serv_sock,clnt_sock;
	struct sockaddr_in serv_addr,clnt_addr;
	socklen_t addr_size;
	int str_len;
	struct timeval timeout;
	fd_set reads,cpy_reads;
	int fd_max,fd_num,i;
	char buf[BUF_SIZE];
	if(argc!=2)
	{
		printf("Usage error");
		exit(1);
	}


	serv_sock = socket(PF_INET,SOCK_STREAM,0);
	memset(&serv_addr,0,sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
	serv_addr.sin_port = htons(atoi(argv[1]));

	if(bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr))==-1)
		error_handling("bind() err");
	if(listen(serv_sock,5)==-1)
		error_handling("listen err");

	FD_ZERO(&reads);
	FD_SET(serv_sock,&reads);
	fd_max=serv_sock;

	while(1)
	{
		cpy_reads=reads;
		timeout.tv_sec=5;
		timeout.tv_usec=5000;

		if((fd_num=select(fd_max+1,&cpy_reads,0,0,&timeout))==-1)
			break;
		if(fd_num==0)//timeout
			continue;
		for(i=0;i<fd_max+1;i++)
		{
			if(FD_ISSET(i,&cpy_reads))//cpy_reads i index if 1 return true
			{
				if(i==serv_sock)
				{
					addr_size=sizeof(clnt_addr);
					clnt_sock = accept(serv_sock,(struct sockaddr*)&clnt_addr,&addr_size);
					FD_SET(clnt_sock,&reads);
				}
				if(fd_max<clnt_sock)
					fd_max=clnt_sock;
				printf("connected client : %d\n",clnt_sock);
			}
			else
			{
				str_len=read(i,buf,BUF_SIZE);
				if(str_len==0)
				{
					FD_CLR(i,&reads);
					close(i);
					printf("Closed client : %d\n",i);
				}
				else
				{
					write(i,buf,str_len);//echo
				}
			}
		}
	}
	close(serv_sock);

	return 0;
}
void error_handling(char* msg)
{
    fputs(msg,stderr);
    fputc('\n',stderr);
    exit(1);
}