epoll_create, epoll_ctl和epoll_wait

参考代码

  1 #include <iostream>
  2 #include <sys/socket.h>
  3 #include <sys/epoll.h>
  4 #include <netinet/in.h>
  5 #include <arpa/inet.h>
  6 #include <fcntl.h>
  7 #include <unistd.h>
  8 #include <stdio.h>
  9 #include <errno.h>
 10 
 11 using namespace std;
 12 
 13 #define MAXLINE 5
 14 #define OPEN_MAX 100
 15 #define LISTENQ 20
 16 #define SERV_PORT 5000
 17 #define INFTIM 1000
 18 
 19 void setnonblocking(int sock)
 20 {
 21     int opts;
 22     opts=fcntl(sock,F_GETFL);
 23     if(opts<0)
 24     {
 25         perror("fcntl(sock,GETFL)");
 26         exit(1);
 27     }
 28     opts = opts|O_NONBLOCK;
 29     if(fcntl(sock,F_SETFL,opts)<0)
 30     {
 31         perror("fcntl(sock,SETFL,opts)");
 32         exit(1);
 33     }
 34 }
 35 
 36 int main(int argc, char* argv[])
 37 {
 38     int i, maxi, listenfd, connfd, sockfd,epfd,nfds, portnumber;
 39     ssize_t n;
 40     char line[MAXLINE];
 41     socklen_t clilen;
 42 
 43 
 44     if ( 2 == argc )
 45     {
 46         if( (portnumber = atoi(argv[1])) < 0 )
 47         {
 48             fprintf(stderr,"Usage:%s portnumber/a/n",argv[0]);
 49             return 1;
 50         }
 51     }
 52     else
 53     {
 54         fprintf(stderr,"Usage:%s portnumber/a/n",argv[0]);
 55         return 1;
 56     }
 57 
 58 
 59 
 60     //声明epoll_event结构体的变量,ev用于注册事件,数组用于回传要处理的事件
 61 
 62     struct epoll_event ev,events[20];
 63     //生成用于处理accept的epoll专用的文件描述符
 64 
 65     epfd=epoll_create(256);
 66     struct sockaddr_in clientaddr;
 67     struct sockaddr_in serveraddr;
 68     listenfd = socket(AF_INET, SOCK_STREAM, 0);
 69     //把socket设置为非阻塞方式
 70 
 71     //setnonblocking(listenfd);
 72 
 73     //设置与要处理的事件相关的文件描述符
 74 
 75     ev.data.fd=listenfd;
 76     //设置要处理的事件类型
 77 
 78     ev.events=EPOLLIN|EPOLLET;
 79     //ev.events=EPOLLIN;
 80 
 81     //注册epoll事件
 82 
 83     epoll_ctl(epfd,EPOLL_CTL_ADD,listenfd,&ev);
 84     bzero(&serveraddr, sizeof(serveraddr));
 85     serveraddr.sin_family = AF_INET;
 86     char *local_addr="127.0.0.1";
 87     inet_aton(local_addr,&(serveraddr.sin_addr));//htons(portnumber);
 88 
 89     serveraddr.sin_port=htons(portnumber);
 90     bind(listenfd,(sockaddr *)&serveraddr, sizeof(serveraddr));
 91     listen(listenfd, LISTENQ);
 92     maxi = 0;
 93     for ( ; ; ) {
 94         //等待epoll事件的发生
 95 
 96         nfds=epoll_wait(epfd,events,20,500);
 97         //处理所发生的所有事件
 98 
 99         for(i=0;i<nfds;++i)
100         {
101             if(events[i].data.fd==listenfd)//如果新监测到一个SOCKET用户连接到了绑定的SOCKET端口，建立新的连接。
102 
103             {
104                 connfd = accept(listenfd,(sockaddr *)&clientaddr, &clilen);
105                 if(connfd<0){
106                     perror("connfd<0");
107                     exit(1);
108                 }
109                 //setnonblocking(connfd);
110 
111                 char *str = inet_ntoa(clientaddr.sin_addr);
112                 cout << "accapt a connection from " << str << endl;
113                 //设置用于读操作的文件描述符
114 
115                 ev.data.fd=connfd;
116                 //设置用于注测的读操作事件
117 
118                 ev.events=EPOLLIN|EPOLLET;
119                 //ev.events=EPOLLIN;
120 
121                 //注册ev
122 
123                 epoll_ctl(epfd,EPOLL_CTL_ADD,connfd,&ev);
124             }
125             else if(events[i].events&EPOLLIN)//如果是已经连接的用户，并且收到数据，那么进行读入。
126 
127             {
128                 cout << "EPOLLIN" << endl;
129                 if ( (sockfd = events[i].data.fd) < 0)
130                     continue;
131                 if ( (n = read(sockfd, line, MAXLINE)) < 0) {
132                     if (errno == ECONNRESET) {
133                         close(sockfd);
134                         events[i].data.fd = -1;
135                     } else
136                         std::cout<<"readline error"<<std::endl;
137                 } else if (n == 0) {
138                     close(sockfd);
139                     events[i].data.fd = -1;
140                 }
141                 line[n] = '/0';
142                 cout << "read " << line << endl;
143                 //设置用于写操作的文件描述符
144 
145                 ev.data.fd=sockfd;
146                 //设置用于注测的写操作事件
147 
148                 ev.events=EPOLLOUT|EPOLLET;
149                 //修改sockfd上要处理的事件为EPOLLOUT
150 
151                 //epoll_ctl(epfd,EPOLL_CTL_MOD,sockfd,&ev);
152 
153             }
154             else if(events[i].events&EPOLLOUT) // 如果有数据发送
155 
156             {
157                 sockfd = events[i].data.fd;
158                 write(sockfd, line, n);
159                 //设置用于读操作的文件描述符
160 
161                 ev.data.fd=sockfd;
162                 //设置用于注测的读操作事件
163 
164                 ev.events=EPOLLIN|EPOLLET;
165                 //修改sockfd上要处理的事件为EPOLIN
166 
167                 epoll_ctl(epfd,EPOLL_CTL_MOD,sockfd,&ev);
168             }
169         }
170     }
171     return 0;
172 }

View Code

  1 //   
  2 // a simple echo server using epoll in linux  
  3 //   
  4 // 2009-11-05  
  5 // 2013-03-22:修改了几个问题，1是/n格式问题，2是去掉了原代码不小心加上的ET模式;
  6 // 本来只是简单的示意程序，决定还是加上 recv/send时的buffer偏移
  7 // by sparkling  
  8 //   
  9 #include <sys/socket.h>  
 10 #include <sys/epoll.h>  
 11 #include <netinet/in.h>  
 12 #include <arpa/inet.h>  
 13 #include <fcntl.h>  
 14 #include <unistd.h>  
 15 #include <stdio.h>  
 16 #include <errno.h>  
 17 #include <iostream>  
 18 using namespace std;  
 19 #define MAX_EVENTS 500  
 20 struct myevent_s  
 21 {  
 22     int fd;  
 23     void (*call_back)(int fd, int events, void *arg);  
 24     int events;  
 25     void *arg;  
 26     int status; // 1: in epoll wait list, 0 not in  
 27     char buff[128]; // recv data buffer  
 28     int len, s_offset;  
 29     long last_active; // last active time  
 30 };  
 31 // set event  
 32 void EventSet(myevent_s *ev, int fd, void (*call_back)(int, int, void*), void *arg)  
 33 {  
 34     ev->fd = fd;  
 35     ev->call_back = call_back;  
 36     ev->events = 0;  
 37     ev->arg = arg;  
 38     ev->status = 0;
 39     bzero(ev->buff, sizeof(ev->buff));
 40     ev->s_offset = 0;  
 41     ev->len = 0;
 42     ev->last_active = time(NULL);  
 43 }  
 44 // add/mod an event to epoll  
 45 void EventAdd(int epollFd, int events, myevent_s *ev)  
 46 {  
 47     struct epoll_event epv = {0, {0}};  
 48     int op;  
 49     epv.data.ptr = ev;  
 50     epv.events = ev->events = events;  
 51     if(ev->status == 1){  

 52         op = EPOLL_CTL_MOD;  
 53     }  
 54     else{  
 55         op = EPOLL_CTL_ADD;  
 56         ev->status = 1;  
 57     }  
 58     if(epoll_ctl(epollFd, op, ev->fd, &epv) < 0)  
 59         printf("Event Add failed[fd=%d], evnets[%d]\n", ev->fd, events);  
 60     else  
 61         printf("Event Add OK[fd=%d], op=%d, evnets[%0X]\n", ev->fd, op, events);  
 62 }  
 63 // delete an event from epoll  
 64 void EventDel(int epollFd, myevent_s *ev)  
 65 {  
 66     struct epoll_event epv = {0, {0}};  
 67     if(ev->status != 1) return;  
 68     epv.data.ptr = ev;  
 69     ev->status = 0;
 70     epoll_ctl(epollFd, EPOLL_CTL_DEL, ev->fd, &epv);  
 71 }  
 72 int g_epollFd;  
 73 myevent_s g_Events[MAX_EVENTS+1]; // g_Events[MAX_EVENTS] is used by listen fd  
 74 void RecvData(int fd, int events, void *arg);  
 75 void SendData(int fd, int events, void *arg);  
 76 // accept new connections from clients  
 77 void AcceptConn(int fd, int events, void *arg)  
 78 {  
 79     struct sockaddr_in sin;  
 80     socklen_t len = sizeof(struct sockaddr_in);  
 81     int nfd, i;  
 82     // accept  
 83     if((nfd = accept(fd, (struct sockaddr*)&sin, &len)) == -1)  
 84     {  
 85         if(errno != EAGAIN && errno != EINTR)  
 86         {  
 87         }
 88         printf("%s: accept, %d", __func__, errno);  
 89         return;  
 90     }  
 91     do  
 92     {  
 93         for(i = 0; i < MAX_EVENTS; i++)  
 94         {  
 95             if(g_Events[i].status == 0)  
 96             {  
 97                 break;  
 98             }  
 99         }  
100         if(i == MAX_EVENTS)  
101         {  
102             printf("%s:max connection limit[%d].", __func__, MAX_EVENTS);  
103             break;  
104         }  
105         // set nonblocking
106         int iret = 0;
107         if((iret = fcntl(nfd, F_SETFL, O_NONBLOCK)) < 0)
108         {
109             printf("%s: fcntl nonblocking failed:%d", __func__, iret);
110             break;
111         }
112         // add a read event for receive data  
113         EventSet(&g_Events[i], nfd, RecvData, &g_Events[i]);  
114         EventAdd(g_epollFd, EPOLLIN, &g_Events[i]);  
115     }while(0);  
116     printf("new conn[%s:%d][time:%d], pos[%d]\n", inet_ntoa(sin.sin_addr), 
117             ntohs(sin.sin_port), g_Events[i].last_active, i);  
118 }  
119 // receive data  
120 void RecvData(int fd, int events, void *arg)  
121 {  
122     struct myevent_s *ev = (struct myevent_s*)arg;  
123     int len;  
124     // receive data
125     len = recv(fd, ev->buff+ev->len, sizeof(ev->buff)-1-ev->len, 0);    
126     EventDel(g_epollFd, ev);
127     if(len > 0)
128     {
129         ev->len += len;
130         ev->buff[len] = '\0';  
131         printf("C[%d]:%s\n", fd, ev->buff);  
132         // change to send event  
133         EventSet(ev, fd, SendData, ev);  
134         EventAdd(g_epollFd, EPOLLOUT, ev);  
135     }  
136     else if(len == 0)  
137     {  
138         close(ev->fd);  
139         printf("[fd=%d] pos[%d], closed gracefully.\n", fd, ev-g_Events);  
140     }  
141     else  
142     {  
143         close(ev->fd);  
144         printf("recv[fd=%d] error[%d]:%s\n", fd, errno, strerror(errno));  
145     }  
146 }  
147 // send data  
148 void SendData(int fd, int events, void *arg)  
149 {  
150     struct myevent_s *ev = (struct myevent_s*)arg;  
151     int len;  
152     // send data  
153     len = send(fd, ev->buff + ev->s_offset, ev->len - ev->s_offset, 0);
154     if(len > 0)  
155     {
156         printf("send[fd=%d], [%d<->%d]%s\n", fd, len, ev->len, ev->buff);
157         ev->s_offset += len;
158         if(ev->s_offset == ev->len)
159         {
160             // change to receive event
161             EventDel(g_epollFd, ev);  
162             EventSet(ev, fd, RecvData, ev);  
163             EventAdd(g_epollFd, EPOLLIN, ev);  
164         }
165     }  
166     else  
167     {  
168         close(ev->fd);  
169         EventDel(g_epollFd, ev);  
170         printf("send[fd=%d] error[%d]\n", fd, errno);  
171     }  
172 }  
173 void InitListenSocket(int epollFd, short port)  
174 {  
175     int listenFd = socket(AF_INET, SOCK_STREAM, 0);  
176     fcntl(listenFd, F_SETFL, O_NONBLOCK); // set non-blocking  
177     printf("server listen fd=%d\n", listenFd);  
178     EventSet(&g_Events[MAX_EVENTS], listenFd, AcceptConn, &g_Events[MAX_EVENTS]);  
179     // add listen socket  
180     EventAdd(epollFd, EPOLLIN, &g_Events[MAX_EVENTS]);  
181     // bind & listen  
182     sockaddr_in sin;  
183     bzero(&sin, sizeof(sin));  
184     sin.sin_family = AF_INET;  
185     sin.sin_addr.s_addr = INADDR_ANY;  
186     sin.sin_port = htons(port);  
187     bind(listenFd, (const sockaddr*)&sin, sizeof(sin));  
188     listen(listenFd, 5);  
189 }  
190 int main(int argc, char **argv)  
191 {  
192     unsigned short port = 12345; // default port  
193     if(argc == 2){  
194         port = atoi(argv[1]);  
195     }  
196     // create epoll  
197     g_epollFd = epoll_create(MAX_EVENTS);  
198     if(g_epollFd <= 0) printf("create epoll failed.%d\n", g_epollFd);  
199     // create & bind listen socket, and add to epoll, set non-blocking  
200     InitListenSocket(g_epollFd, port);  
201     // event loop  
202     struct epoll_event events[MAX_EVENTS];  
203     printf("server running:port[%d]\n", port);  
204     int checkPos = 0;  
205     while(1){  
206         // a simple timeout check here, every time 100, better to use a mini-heap, and add timer event  
207         long now = time(NULL);  
208         for(int i = 0; i < 100; i++, checkPos++) // doesn't check listen fd  
209         {  
210             if(checkPos == MAX_EVENTS) checkPos = 0; // recycle  
211             if(g_Events[checkPos].status != 1) continue;  
212             long duration = now - g_Events[checkPos].last_active;  
213             if(duration >= 60) // 60s timeout  
214             {  
215                 close(g_Events[checkPos].fd);  
216                 printf("[fd=%d] timeout[%d--%d].\n", g_Events[checkPos].fd, g_Events[checkPos].last_active, now);  
217                 EventDel(g_epollFd, &g_Events[checkPos]);  
218             }  
219         }  
220         // wait for events to happen  
221         int fds = epoll_wait(g_epollFd, events, MAX_EVENTS, 1000);  
222         if(fds < 0){  
223             printf("epoll_wait error, exit\n");  
224             break;  
225         }  
226         for(int i = 0; i < fds; i++){  
227             myevent_s *ev = (struct myevent_s*)events[i].data.ptr;  
228             if((events[i].events&EPOLLIN)&&(ev->events&EPOLLIN)) // read event  
229             {  
230                 ev->call_back(ev->fd, events[i].events, ev->arg);  
231             }  
232             if((events[i].events&EPOLLOUT)&&(ev->events&EPOLLOUT)) // write event  
233             {  
234                 ev->call_back(ev->fd, events[i].events, ev->arg);  
235             }  
236         }  
237     }  
238     // free resource  
239     return 0;  
240 }