#include<stdio.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<sys/select.h>
#include<stdlib.h>
#include<unistd.h>
int fds[sizeof(fd_set)*8];
static void usage(const char *proc)
{
printf("%s [local_ip] [local_port]\n",proc);
}
int startup(const char *ip,int port)
{
int sock = socket(AF_INET,SOCK_STREAM,0);
if(sock < 0)
{
perror("sock");
exit(2);
}
int opt = 1;
setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));
struct sockaddr_in local;
local.sin_family = AF_INET;
local.sin_port = htons(port);
local.sin_addr.s_addr = inet_addr(ip);
if(bind(sock,(struct sockaddr*)&local,sizeof(local)) < 0)
{
perror("bind");
exit(3);
}
if(listen(sock,10) < 0)
{
perror("listen");
exit(4);
}
return sock;
}
int main(int argc,char *argv[])
{
if(argc != 3)
{
usage(argv[0]);
return 1;
}
int listen_sock = startup(argv[1],atoi(argv[2]));// listen a link just like care read events
int nums = sizeof(fds)/sizeof(fds[0]);
int i = 0;//set array start_value
for(;i < nums;++i)
{
fds[i] = -1;
}
fds[0] = listen_sock;
fd_set rfds;
while(1)
{
int maxfd = -1;
struct timeval timeout = {2,0};
FD_ZERO(&rfds);
i = 0;
for(;i < nums;++i) //set fd_set and find maxfd
{
if(fds[i] == -1)
{
continue;
}
FD_SET(fds[i],&rfds);
if(maxfd < fds[i])
{
maxfd = fds[i];
}
}
switch(select(maxfd+1,&rfds,NULL,NULL,NULL))
{
case -1:
break;
case 0:
printf("timeout....\n");
break;
default://at least one fd ready
{
i = 0;
for(;i < nums;++i)
{
if(i == 0&&FD_ISSET(fds[i],&rfds))//have ready,can start to accept
{
struct sockaddr_in client;
socklen_t len = sizeof(client);
int new_socket = accept(listen_sock,(struct sockaddr*)&client,&len);//can not blocked
if(new_socket < 0)
{
perror("accept");
continue;
}
printf("get a client: [%s:%d]\n",inet_ntoa(client.sin_addr),ntohs(client.sin_port));
int j = 1;
for(;j < nums;++j)
{
if(fds[j] == -1) //find a position for new_socket,if new_socket ready,start to write/read
{
break;
}
}
if(j == nums)
{
close(new_socket); //the fd_set is full,can not handler this link,close it
}
else
{
fds[j] = new_socket;
}
}
else if(i != 0&&FD_ISSET(fds[i],&rfds)) //new_socket ready ,start to write/read ,not be blocked
{
char buf[1024];
ssize_t s = read(fds[i],buf,sizeof(buf)-1);
if(s > 0)
{
buf[s] = 0;
printf("client#%s\n",buf);
}
else if(s == 0)
{
printf("client is quit!!!\n");
close(fds[i]); //not only close this link
fds[i] = -1; //but also set the array,next run do not care the fds
}
else
{
perror("read");
close(fds[i]);
fds[i] = -1;
}
}
}
}
}
}
return 0;
}
