epoll池用法

布满荆棘的人生 2022-07-14 09:13 114阅读 0赞

**声明：本博文用于学习总结及工作心得**

解决高并发， 替代线程方式，但是效率不及线程

代码：

main
    #include <stdio.h>
    #include <stdlib.h>
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <string.h>
    #include <errno.h>
    #include <unistd.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #include <pthread.h>
    #include <sys/epoll.h>
    #include <fcntl.h>
    
    
    int main(int arg, char *args[])
    {
    	if(arg < 2)
    	{
    		return -1;
    	}
    	int iport = atoi(args[1]);
    	int listen_st = socket_create(iport);
    	if(listen_st == 0)
    	{
    		return -1;
    	}
    	//声明epoll_event结构体变量,ev用于注册事件,数组用于回传要处理的事件
    	struct epoll_event ev,events[100];
    	//生成用于处理accept的epoll专用的文件描述符
    	int epfd = epoll_create(100);
    	//把socket设置为非阻塞方式
    	setnonblocking(listen_st);
    	ev.data.fd = listen_st;//设置要处理的事件相关文件描述符
    	ev.events = EPOLLIN | EPOLLERR | EPOLLHUP;//设置要处理的事件类型
    	epoll_ctl(epfd, EPOLL_CTL_ADD, listen_st, &ev);//注册epoll事件
    
    	int st = 0;
    	while(1)
    	{
    		int nfds = epoll_wait(epfd, events, 100, -1);
    		if(nfds == -1)
    		{
    			printf("epoll_wait failed %s\n", strerror(errno));
    			break;
    		}
    		int i = 0;
    		for(i =0; i< nfds; i++)
    		{
    			if(events[i].data.fd < 0)
    			{
    				continue;
    			}
    			if(events[i].data.fd == listen_st)
    			{
    				st = scoket_accept(listen_st);
    				if(st >= 0)
    				{
    					setnonblocking(st);
    					ev.data.fd = st;
    					ev.events = EPOLLIN | EPOLLERR | EPOLLHUP;//设置要处理的事件类型
    					epoll_ctl(epfd, EPOLL_CTL_ADD, st, &ev);
    					continue;
    				}
    			}
    
    			//client端的socket有事件到达
    			if(events[i].events & EPOLLIN) //socket收到数据
    			{
    				st = events[i].data.fd;
    				if(socket_recv(st) <=0)
    				{
    					close(st);
    					events[i].data.fd = -1;
    				}
    			}
    			if(events[i].events & EPOLLERR)//socket 错误
    			{
    				st = events[i].data.fd;
    				close(st);
    				events[i].data.fd = -1;
    			}
    			if(events[i].events & EPOLLHUP)//socket关闭
    			{
    				st = events[i].data.fd;
    				close(st);
    				events[i].data.fd = -1;
    			}
    		}
    	}
    	close(epfd);
    	return EXIT_SUCCESS;
    }

创建socket
    int socket_create(int port)
    {
    	int st = socket(AF_INET, SOCK_STREAM, 0);
    	int on =0;
    	if(setsockopt(st, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
    	{
    		printf("setsockopt failed %s\n", strerror(errno));
    		return 0;
    	}
    	struct sockaddr_in addr;
    	memset(&addr, 0, sizeof(addr));
    	addr.sin_family = AF_INET;
    	addr.sin_port = htons(port);
    	addr.sin_addr.s_addr = htonl(INADDR_ANY);
    	if(bind(st, (struct sockaddr *)&addr, sizeof(addr)) == -1)
    	{
    		printf("bind port %d failed %s\n", port, strerror(errno));
    		return 0;
    	}
    	if(listen(st, 300) == -1)
    	{
    		printf("listen failed %s\n", strerror(errno));
    		return 0;
    	}
    	return st;
    }

连接client端
    
    int scoket_accept(int listen_st)
    {
    	struct sockaddr_in client_addr;
    	socklen_t len = sizeof(client_addr);
    	memset(&client_addr, 0, sizeof(client_addr));
    	int client_st = accept(listen_st,
    			(struct sockaddr *)&client_addr, &len);
    	if(client_st < 0)
    	{
    		printf("accept failed %s\n", strerror(errno));
    	}
    	else
    	{
    		printf("accept by %s\n", inet_ntoa(client_addr.sin_addr));
    	}
    	return client_st;
    }

收发消息
    
    ssize_t socket_recv(int st)
    {
    	char buf[1024];
    	memset(buf, 0, sizeof(buf));
    	ssize_t rc = recv(st, buf, sizeof(buf), 0);
    	if(rc <= 0)
    	{
    		printf("recv failed %s\n", strerror(errno));
    	}
    	else
    	{
    		printf("recv %s\n", buf);
    		send(st, buf, rc, 0);
    	}
    	return rc;
    }

设置socket非阻塞方式
    void setnonblocking(int st)
    {
    	int opts = fcntl(st, F_GETFL);
    	if(opts < 0)
    	{
    		printf("fcntl failed %s\n", strerror(errno));
    	}
    	opts = opts | O_NONBLOCK;
    	if(fcntl(st, F_SETFL, opts) < 0)
    	{
    		printf("fcntl failed %s\n", strerror(errno));
    	}
    }

**makefile:**

.SUFFIXES:.c .o CC=gcc SRCS=epoll.c OBJS=$(SRCS:.c=.o) EXEC=epoll start: $(OBJS) $(CC) -o $(EXEC) $(OBJS) @echo '-----------OK-----------' .c.o: $(CC) -Wall -g -o $@ -c $< clean: rm -rf $(OBJS)