LinuxIO多路复用之poll

#include <sys/types.h>
#include <poll.h>
#include <sys/socket.h>
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <arpa/inet.h>

#define SERV_PORT 8080
#define MAXSIZE 1024
#define MAXLINE 64

void sys_err(const char *fun_str,int exitno)
{
perror("fun_str");
exit(exitno);
}

int main()
{
int sockfd, listenfd, connfd;
struct sockaddr_in serv_addr,cli_addr;
int ret;
socklen_t cli_len;
int len;
int nready;
char buf[MAXSIZE];
struct pollfd client[MAXSIZE];
int i=0,maxi=0;
char addr[MAXLINE];

listenfd = socket(AF_INET, SOCK_STREAM, 0);
if(listenfd<0)
{
sys_err("socket",-1);
}

bzero(&serv_addr, sizeof(serv_addr));

serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(SERV_PORT);

ret = bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
if(ret <0)
{
sys_err("bind",-2);
}

ret = listen(listenfd,20);
if(ret <0 )
{
sys_err("listen",-3);
}

client[0].fd = listenfd;
client[0].events = POLLIN;

for(i=1; i<MAXSIZE; i++)
{
client[i].fd = -1;
}
printf("accept client connect\n");
while(1)
{
nready = poll(client, maxi+1, -1);
if(nready <0)
{
sys_err("poll",-4);
}
//new connection
if(client[0].revents & POLLIN)
{
cli_len = sizeof(cli_addr);
connfd = accept(listenfd, (struct sockaddr *)&cli_addr, &cli_len);
if(connfd <0)
{
sys_err("accept",-5);
}
printf("receive from ip %s port %d\n",
inet_ntop(connfd, &serv_addr.sin_addr.s_addr, addr, sizeof(addr)), ntohs(serv_addr.sin_port));

for(i=1; i<MAXSIZE; i++)
{
if(client[i].fd <0)
{
client[i].fd = connfd;
break;
}
}

if(i == MAXSIZE)
{
printf("too many clients\n");
exit(0);
}

client[i].events = POLLIN;

if(i >maxi)
maxi = i;

if(--nready == 0)
continue;
}
for(i=1; i<=maxi; i++)
{
sockfd = client[i].fd;
if(sockfd<0)
continue;
else
{
len = read(sockfd, buf, sizeof(buf));
if(len <0)
sys_err("read",-6);
else if(0 == len)
{
close(connfd);
client[i].fd = -1;
printf("client[%d] close\n",i);
}
else
{
ret = write(sockfd, buf, len);
if(ret<0)
{
sys_err("write",-7);
}
}
}
if(--nready == 0)
break;
}
}
close(listenfd);
return 0;
}