tcps-epoll.cpp

Linux Epoll用法实例（Socket编程）

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <arpa/inet.h>
#include <sys/epoll.h>
#define SERVPORT 9999
#define BACKLOG 10
#define MAXDATASIZE 100
#define MAX_EPOLL_NUM 200

char *strrev(char *str) 
{ 
   char *p1, *p2; 
   if (!str || !*str) 
         return str; 
   for (p1 = str, p2 = str + strlen(str) - 1; p2 > p1; ++p1, --p2) 
   { 
     *p1 ^= *p2; 
     *p2 ^= *p1; 
     *p1 ^= *p2; 
   } 
   return str; 
}

int main(int argc, char *argv[])
{
   int sockFd, connectedFd;
   struct sockaddr_in serv_addr;
   struct sockaddr_in client_addr;
   int epollFd, ackFds;
   struct epoll_event eventReg, epollEvent[MAX_EPOLL_NUM];
   char buf[MAXDATASIZE];
   int recvBytes;   
   
   printf("create the socket...\n");
   if ((sockFd = socket(AF_INET, SOCK_STREAM, 0)) == -1) 
   {
     perror("create socket error!"); 
     exit(1);
   }
   
   serv_addr.sin_family=AF_INET;
   serv_addr.sin_port=htons(SERVPORT);
   serv_addr.sin_addr.s_addr = INADDR_ANY;
   bzero(&(serv_addr.sin_zero),0);   
   
   int yes = 1;
   if (setsockopt(sockFd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1)
   {
     perror("setsockopt error!");
     close(sockFd);
     exit(1);
   }
    
   printf("bind the socket...\n");
   if (bind(sockFd, (struct sockaddr *)&serv_addr, sizeof(struct sockaddr)) == -1) 
   {
     perror("bind error!");
     close(sockFd);
     exit(1);
   }

   printf("socket is listening...\n");   
   if (listen(sockFd, BACKLOG) == -1) 
   {
     perror("listen error!");
     close(sockFd);
     exit(1);
   }

   epollFd = epoll_create(MAX_EPOLL_NUM);
   eventReg.data.fd = sockFd;
   eventReg.events = EPOLLIN;
   if(epoll_ctl(epollFd, EPOLL_CTL_ADD, sockFd, &eventReg) < 0)
   {
     perror("epoll_ctl error!");
     close(sockFd);
     exit(1);
   }

   while(1)
   {
     printf("epollwaitting...\n");
     ackFds = epoll_wait(epollFd, epollEvent, MAX_EPOLL_NUM, -1);
          
     for(int i=0; i<ackFds; i++)
     {
       if (epollEvent[i].data.fd == sockFd)
       {       
	 printf("socket is ready for accept...accepting...\n");
	 socklen_t add_size = sizeof(struct sockaddr_in);
	 if ((connectedFd = accept(epollEvent[i].data.fd, (struct sockaddr *)&client_addr, &add_size)) == -1) 
	 {
	   perror("accept error!");
	   close(epollEvent[i].data.fd);
	   exit(1);
	 }
         else
	 {
           printf("received a connection from %s:%d\n", inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));

	   if (send(connectedFd, "Hello, you are connected!\n", 26, 0) == -1)
	   {
	     perror("send error!");
	     close(connectedFd);
	     continue;
	   }

	   eventReg.data.fd = connectedFd;
	   eventReg.events = EPOLLIN;
	   if(epoll_ctl(epollFd, EPOLL_CTL_ADD, connectedFd, &eventReg) < 0)
	   {
	     perror("1epoll_ctl error!");
	     close(connectedFd);
	     continue;
	   }

	 }

       }
       else
       {
	 recvBytes=-1;
	 if ((recvBytes=recv(epollEvent[i].data.fd, buf, MAXDATASIZE, 0)) ==-1) 
	 {
	   perror("recv error!");
	   eventReg.data.fd = epollEvent[i].data.fd;
	   if(epoll_ctl(epollFd, EPOLL_CTL_DEL, epollEvent[i].data.fd, &eventReg) < 0)
	   {
	     perror("epoll_ctl error!");
	   }
	   close(epollEvent[i].data.fd);
	   continue;
	 }

	 buf[recvBytes] = '\0';
	 printf("Received: %s\n",buf);

	 strcpy(buf, strrev(buf));

	 if (send(epollEvent[i].data.fd, buf, strlen(buf), 0) == -1)
	 {
	   perror("send error!");
	   eventReg.data.fd = epollEvent[i].data.fd;
	   if(epoll_ctl(epollFd, EPOLL_CTL_DEL, epollEvent[i].data.fd, &eventReg) < 0)
	   {
	     perror("epoll_ctl error!");
	   }
	   close(epollEvent[i].data.fd);
	   continue;
	 }

         if (buf[0] == '0')
	 {
           printf("one client exited!\n");
	   eventReg.data.fd = epollEvent[i].data.fd;
	   if(epoll_ctl(epollFd, EPOLL_CTL_DEL, epollEvent[i].data.fd, &eventReg) < 0)
	   {
	     perror("epoll_ctl error!");
	   }
	   close(epollEvent[i].data.fd);
	   continue;
	 }
       }
     }
   }  

   close(sockFd);
     
}