server.cpp

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/epoll.h>
#include <unistd.h>
#include <sys/types.h>

#define IPADDRESS   "127.0.0.1"
#define PORT        6666
#define MAXSIZE     1024 
#define LISTENQ     5
#define FDSIZE      1000
#define EPOLLEVENTS 100

/*函数声明*/
/*创建套接字并进行绑定*/
int socket_bind(const char* ip,int port);
/*IO多路复用epoll*/
void do_epoll(int listenfd);
/*事件处理函数*/
void handle_events(int epollfd,struct epoll_event *events,int num,int listenfd,char *buf);
/*处理接收到的连接*/
void handle_accpet(int epollfd,int listenfd);
/*读处理*/
void do_read(int epollfd,int fd,char *buf);
/*写处理*/
void do_write(int epollfd,int fd,char *buf);
/*添加事件*/
void add_event(int epollfd,int fd,int state);
/*修改事件*/
void modify_event(int epollfd,int fd,int state);
/*删除事件*/
void delete_event(int epollfd,int fd,int state);

int main(int argc,char *argv[]){
	int  listenfd;
	listenfd = socket_bind(IPADDRESS,PORT);
	listen(listenfd,LISTENQ);
	do_epoll(listenfd);
	return 0;
}

int socket_bind(const char* ip,int port){
	int  listenfd;
	struct sockaddr_in servaddr;
	listenfd = socket(AF_INET,SOCK_STREAM,0);
	if (listenfd == -1){
		perror("socket error:");
		exit(1);
	}
	bzero(&servaddr,sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	inet_pton(AF_INET,ip,&servaddr.sin_addr);
	servaddr.sin_port = htons(port);
	if (bind(listenfd,(struct sockaddr*)&servaddr,sizeof(servaddr)) == -1){
		perror("bind error: ");
		exit(1);
	}
	return listenfd;
}

void do_epoll(int listenfd){
	int epollfd;
	struct epoll_event events[EPOLLEVENTS];
	int ret;
	char buf[MAXSIZE];
	memset(buf,0,MAXSIZE);
	/*创建一个描述符*/
	epollfd = epoll_create(FDSIZE);
	/*添加监听描述符事件*/
	add_event(epollfd,listenfd,EPOLLIN);
	static int counter = 0;
	while(1){
		/*获取已经准备好的描述符事件*/
		ret = epoll_wait(epollfd,events,EPOLLEVENTS,-1);
		printf("epoll_wait ret:%d, counter:%d\n", ret, counter++); // add by gaojie, 可以展示有几次触发，如果是水平触发，则会打印很多次，如果是边缘触发，则只会打印一次。
		handle_events(epollfd,events,ret,listenfd,buf);
	}
	close(epollfd);
}

void handle_events(int epollfd,struct epoll_event *events,int num,int listenfd,char *buf){
	int i;
	int fd;
	/*进行选好遍历*/
	for (i = 0;i < num;i++){
		fd = events[i].data.fd;
		/*根据描述符的类型和事件类型进行处理*/
		if ((fd == listenfd) &&(events[i].events & EPOLLIN))
			handle_accpet(epollfd,listenfd);
		else if (events[i].events & EPOLLIN)
			do_read(epollfd,fd,buf);
		else if (events[i].events & EPOLLOUT)
			do_write(epollfd,fd,buf);
	}
}

void handle_accpet(int epollfd,int listenfd){
	int clifd;
	struct sockaddr_in cliaddr;
	socklen_t  cliaddrlen;
	clifd = accept(listenfd,(struct sockaddr*)&cliaddr,&cliaddrlen);
	if (clifd == -1)
		perror("accpet error:");
	else{
		printf("accept a new client: %s:%d\n",inet_ntoa(cliaddr.sin_addr),cliaddr.sin_port);
		/*添加一个客户描述符和事件*/
		add_event(epollfd,clifd,EPOLLIN);
	}
}

void do_read(int epollfd,int fd,char *buf){
	int nread;
	// nread = read(fd,buf,MAXSIZE);

	// gaojie:修改MAXSIZE为1便于演示,因为这样一次就读一个字符，只要client端有多个输入就可以演示出效果 
	nread = read(fd,buf,1);
	if (nread == -1){
		perror("read error:");
		close(fd);
		delete_event(epollfd,fd,EPOLLIN);
	}
	else if (nread == 0){
		fprintf(stderr,"client close.\n");
		close(fd);
		delete_event(epollfd,fd,EPOLLIN);
	}
	else {
		buf[nread] = 0; // add by gaojie, 不会在屏幕上显示特殊符号
		// printf("read message is : %s",buf);
		printf("read message is : %s\n",buf); // modify by gaojie, 添加了换行符
		/*修改描述符对应的事件，由读改为写*/
		// modify_event(epollfd,fd,EPOLLOUT); // comment by gaojie, 不产生干扰
	}
}

void do_write(int epollfd,int fd,char *buf){
	int nwrite;
	nwrite = write(fd,buf,strlen(buf));
	if (nwrite == -1){
		perror("write error:");
		close(fd);
		delete_event(epollfd,fd,EPOLLOUT);
	}
	else
		modify_event(epollfd,fd,EPOLLIN);
	memset(buf,0,MAXSIZE);
}

void add_event(int epollfd,int fd,int state){
	struct epoll_event ev;
	// ev.events = state|EPOLLET; // gaojie: 边缘触发
        ev.events = state; // gaojie: 水平触发
	ev.data.fd = fd;
	epoll_ctl(epollfd,EPOLL_CTL_ADD,fd,&ev);
}

void delete_event(int epollfd,int fd,int state){
	struct epoll_event ev;
	ev.events = state;
	ev.data.fd = fd;
	epoll_ctl(epollfd,EPOLL_CTL_DEL,fd,&ev);
}

void modify_event(int epollfd,int fd,int state){
	struct epoll_event ev;
	ev.events = state;
	ev.data.fd = fd;
	epoll_ctl(epollfd,EPOLL_CTL_MOD,fd,&ev);
}