epoll处理并发请求代码实现及讲解

ch17/echo_client.c

@@ -0,0 +1,59 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+#define BUF_SIZE	1024
+void error_handling(char *message);
+
+int main(int argc,char *argv[]){
+	int sock;
+	struct sockaddr_in serv_addr;
+	char message[BUF_SIZE];
+	int str_len;
+
+	if(argc != 3){
+		printf("Usage : %s <IP> <port>\n",argv[0]);
+		exit(1);
+	}
+
+	sock = socket(PF_INET,SOCK_STREAM,0);
+	if(sock == -1){
+		error_handling("socket() error");
+	}
+
+	memset(&serv_addr,0,sizeof(serv_addr));
+	serv_addr.sin_family = AF_INET;
+	serv_addr.sin_addr.s_addr = inet_addr(argv[1]);
+	serv_addr.sin_port = htons(atoi(argv[2]));
+
+	if(connect(sock,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) == -1){
+		error_handling("connect() error\r\n");
+	}else{
+		printf("Connected....");
+	}
+
+	while(1){
+		printf("Input message(Q to quit):");
+		fgets(message,BUF_SIZE,stdin);
+
+		if(!strcmp(message,"q\n") || !strcmp(message,"Q\n"))
+			break;
+		write(sock,message,strlen(message));
+	//	sleep(5);
+		str_len = read(sock,message,BUF_SIZE-1);
+		message[str_len] = 0;
+
+		printf("Message from server : %s \n",message);
+	}
+	close(sock);
+	return 0;
+}
+
+void error_handling(char *message){
+	fputs(message,stderr);
+	fputs("\n",stderr);
+	exit(1);
+}

ch17/echo_srv.c

@@ -0,0 +1,100 @@
+#include <stdio.h>  
+#include <stdlib.h>  
+#include <string.h>  
+#include <unistd.h>  
+#include <arpa/inet.h>  
+#include <sys/socket.h>  
+#include <sys/epoll.h>
+
+#define BUF_SIZE    100
+#define EPOLL_SIZE	50
+
+void error_handling(char *message);  
+
+int main(int argc, char *argv[]){  
+    int serv_sock,clnt_sock;  
+    char buf[BUF_SIZE];  
+    struct sockaddr_in serv_adr;  
+    struct sockaddr_in clnt_adr;  
+    socklen_t adr_sz;  
+    int str_len,i;
+    struct epoll_event *ep_events;
+    struct epoll_event event;
+    int epfd,event_cnt;  
+
+    if(argc != 2){  
+        printf("Usage : %s <port>\n",argv[0]);  
+        exit(1);  
+    }  
+
+    serv_sock = socket(PF_INET,SOCK_STREAM,0);  
+    if(serv_sock == -1){  
+        error_handling("socket error");  
+    }  
+
+    memset(&serv_adr,0,sizeof(serv_adr));  
+    serv_adr.sin_family=AF_INET;  
+    serv_adr.sin_addr.s_addr=htonl(INADDR_ANY);  
+    serv_adr.sin_port=htons(atoi(argv[1]));  
+
+    if(bind(serv_sock,(struct sockaddr*)&serv_adr,sizeof(serv_adr)) == -1){  
+        error_handling("bind() error");  
+    }  
+
+    if(listen(serv_sock,5) == -1){  //自动生成服务器端套接字（守门员）
+        error_handling("listen() error");  
+    }  
+
+    epfd = epoll_create(EPOLL_SIZE);//创建epoll例程，返回例程的文件描述符
+    ep_events = malloc(sizeof(struct epoll_event)*EPOLL_SIZE);
+    //用于保存发生事件的文件描述符
+    event.events = EPOLLIN;
+    event.data.fd = serv_sock;
+    epoll_ctl(epfd,EPOLL_CTL_ADD,serv_sock,&event);
+    //将serv_sock添加到例程空间中
+    while(1){ 
+	event_cnt = epoll_wait(epfd,ep_events,EPOLL_SIZE,-1);
+    //返回发生事件的文件描述符个数
+	if(event_cnt  == -1){
+	    puts("epoll wait error");
+	    break;
+	}
+
+	for(i=0;i<event_cnt;i++){
+	    if(ep_events[i].data.fd == serv_sock){
+		adr_sz = sizeof(clnt_adr);
+        	clnt_sock = accept(serv_sock,(struct sockaddr *)&clnt_adr,&adr_sz);  
+		    //处理请求套接字生成
+		event.events = EPOLLIN;
+		event.data.fd = clnt_sock;
+		epoll_ctl(epfd,EPOLL_CTL_ADD,clnt_sock,&event);
+		//将发生请求的套接字添加到epoll例程中
+		printf("connected client : %d \n", clnt_sock);
+	    }else{	//read message
+		//这个地方设计的可能有点啰嗦，不如直接写入，这里先通过读，判断了字符串数据读取的字节数
+		str_len = read(ep_events[i].data.fd,buf,BUF_SIZE);
+        //将文件描述符的缓冲区里的数据拷贝到buf缓冲文件中
+		if(str_len == 0){	//close
+		    epoll_ctl(epfd,EPOLL_CTL_DEL,ep_events[i].data.fd,NULL);
+			//如果文件描述符的缓冲中没有数据，就将该fd从epoll例程中移除
+		    close(ep_events[i].data.fd);//同时关闭该文件描述符对应的套接字
+		    printf("closed client %d \n",ep_events[i].data.fd);
+		}else{
+			write(ep_events[i].data.fd,buf,str_len);	//echo
+            //从buf里把数据写入到文件描述符对应的套接字缓冲区里
+
+		}	    
+	    }
+	}
+    }  
+    close(serv_sock);  
+    close(epfd);
+    return 0;  
+}  
+
+void error_handling(char *message){  
+
+    fputs(message,stderr);  
+    fputs("\n",stderr);  
+    exit(1);  
+}