使用poll实现的io多路复用服务端和客户端

参考：http://www.cnblogs.com/Anker/p/3261006.html

使用poll实现的io多路复用服务端和客户端。

客户端通过子进程创建多个客户端连接。

客户端每隔1秒向服务端发送一个时间戳，

服务端接收到时间戳以后，保存在本地的文件中，

一个客户端对应一个存储文件，

并将接收到的时间戳返回给客户端。

代码：

服务端：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <errno.h>
#include <unistd.h>

#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#define IP_ADDR "127.0.0.1"
#define PORT 59999
#define LISTEN_Q 5
#define OPEN_MAX 100000
#define INFTIM -1
#define MAX_LINE 1024

static int socket_bind(const char* ip, int port);
static void do_poll(int ln_fd);
static void handle_conn(struct pollfd* conn_fds, int num, int* files);

int main()
{
int ln_fd, cn_fd, sk_fd = 0;
struct sockaddr_in _addr;

socklen_t _len;
ln_fd = socket_bind(IP_ADDR, PORT);
listen(ln_fd, LISTEN_Q);

do_poll(ln_fd);
return 0;
}

static int socket_bind(const char* ip, int port)
{
int ln_fd;
struct sockaddr_in _addr;
ln_fd = socket(AF_INET, SOCK_STREAM, 0);
if(ln_fd == -1) {
perror("socket error!");
exit(1);
}

bzero(&_addr, sizeof(_addr));
_addr.sin_family = AF_INET;
inet_pton(AF_INET, ip, &_addr.sin_addr);
_addr.sin_port = htons(port);

if(bind(ln_fd, (struct sockaddr*)&_addr, sizeof(_addr)) == -1) {
perror("bind error!");
exit(1);
}

return ln_fd;
}

static void do_poll(int ln_fd)
{
int connfd, sockfd = 0;
struct sockaddr_in _addr;
socklen_t _len;
int files[OPEN_MAX];
struct pollfd clients[OPEN_MAX];
int nMax, i, nReady = 0;

clients[0].fd = ln_fd;
clients[0].events = POLLIN;

for(i = 1; i<OPEN_MAX; ++i) {
clients[i].fd = -1;
}
nMax = 0;

while(1) {
nReady = poll(clients, nMax+1, INFTIM);
if(nReady == -1) {
perror("poll error!");
exit(1);
}
else {
printf("poll ready num = %d\n", nReady);
}

if(clients[0].revents & POLLIN) {
_len = sizeof(_addr);
if((connfd = accept(ln_fd, (struct sockaddr*)&_addr, &_len)) == -1) {
if(errno == EINTR) {
printf("EINTR!\n");
continue;
}
else {
perror("accept error!");
exit(1);
}
}

fprintf(stdout, "accept a new client! [%s]\n", inet_ntoa(_addr.sin_addr));

for(i=1; i<OPEN_MAX; ++i) {
if(clients[i].fd < 0) {
fcntl(connfd, F_SETFL, fcntl(connfd,F_GETFL)| O_NONBLOCK);
unsigned long nVal=1;
ioctl(connfd, FIONBIO, &nVal);

clients[i].fd = connfd;
char path[2048] = {"\0"};
getcwd(path, sizeof(path));

sprintf(path, "%s/tmp_%d.txt", path, i);
printf("path=%s\n", path);
int fd = open(path, O_RDWR|O_APPEND|O_CREAT, 0666);
if(fd > 0) {
files[i] = fd;
}
else {
fprintf(stdout, "open file error! [%s]\n", path);
perror("open file error!");
}

break;
}
}

fflush(stdout);

if(i == OPEN_MAX) {
fprintf(stderr, "too many clients\n");
exit(1);
}

clients[i].events = POLLIN;
nMax = (i > nMax ? i : nMax);
if(--nReady <= 0) {
printf("nReady = %d, nMax = %d\n", nReady, nMax);
continue;
}
}

handle_conn(clients, nMax, files);
}
}

static void handle_conn(struct pollfd* conn_fds, int num, int* files)
{
int i, n = 0;
char buf[MAX_LINE];
memset(buf, 0, MAX_LINE);
for(i=1; i<=num; ++i)
{
if(conn_fds[i].fd < 0)
continue;

if(conn_fds[i].revents & POLLIN) {
n = read(conn_fds[i].fd, buf, MAX_LINE);
if(n == 0) {
close(conn_fds[i].fd);
conn_fds[i].fd = -1;
continue;
}

write(files[i], buf, n);
write(conn_fds[i].fd, buf, n);
}
}
}


客户端：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <poll.h>
#include <errno.h>
#include <arpa/inet.h>

#define MAX_LINE 1024
#define IP_ADDR "127.0.0.1"
#define SERV_PORT 59999

#define max(a,b) (a>b)?a:b

static void do_conn();
static void handle_conn(int sockfd);

int main(int args, char* argv[])
{
int i = 0;
for(i=0; i<2000; ++i) {
pid_t fpid = -1;
fpid = fork();
if(fpid < 0) {
printf("error in fork!");
}
else if(fpid == 0) {
do_conn();
}
else {
//do_conn();
}
}

return 0;
}

static void do_conn()
{
int sockfd;
struct sockaddr_in _addr;
sockfd = socket(AF_INET, SOCK_STREAM, 0);

bzero(&_addr, sizeof(_addr));
_addr.sin_family = AF_INET;
_addr.sin_port = htons(SERV_PORT);

inet_pton(AF_INET, IP_ADDR, &_addr.sin_addr);
int ret = connect(sockfd, (struct sockaddr*)&_addr, sizeof(_addr));
if(ret < 0) {
perror("connect failed!");
exit(1);
}

handle_conn(sockfd);
}

static void handle_conn(int sockfd)
{
char send_line[MAX_LINE] = {'\0'};
char recv_line[MAX_LINE] = {'\0'};

struct pollfd pfds[1];
pfds[0].fd = sockfd;
pfds[0].events = POLLIN|POLLOUT;

while(1) {
poll(pfds, 1, 1000);
if(pfds[0].revents & POLLIN) {
int ret = read(sockfd, recv_line, MAX_LINE);
if(ret == 0) {
perror("client: server is closed.");
close(sockfd);
continue;
}
else if(ret < 0) {
perror("client: read error!");
continue;
}

//printf("[%d] recv=%s\n", (int)getpid(), recv_line);
}

if(pfds[0].revents & POLLOUT) {
time_t _time = time(0);
char dt[20]={"\0"};
sprintf(dt, "%d\n", _time);

memcpy(send_line, dt, strlen(dt));
int ret = write(sockfd, send_line, strlen(send_line));
if(ret < 0) {
perror("write error!!");
}
}

sleep(1);
}

shutdown(sockfd, SHUT_WR);
}