# 3.2 epoll的反應堆模式實現 >epoll反應堆模式的實現-也就是libevent的實現原理。 ```go #include <stdlib.h> #include <stdio.h> #include <stdio.h> #include <sys/socket.h> #include <sys/epoll.h> #include <arpa/inet.h> #include <fcntl.h> #include <unistd.h> #include <errno.h> #include <string.h> #include <time.h> #define MAX_EVENTS 1024 #define BUFLEN 128 #define SERV_PORT 8080 /* * status:1表示在監聽事件中，0表示不在 * last_active:記錄最后一次響應時間,做超時處理 */ struct myevent_s { int fd; //cfd listenfd int events; //EPOLLIN EPLLOUT void *arg; //指向自己結構體指針 void (*call_back)(int fd, int events, void *arg); int status; char buf[BUFLEN]; int len; long last_active; }; int g_efd; /* epoll_create返回的句柄 */ struct myevent_s g_events[MAX_EVENTS+1]; /* +1 最后一個用于 listen fd */ void eventset(struct myevent_s *ev, int fd, void (*call_back)(int, int, void *), void *arg) { ev->fd = fd; ev->call_back = call_back; ev->events = 0; ev->arg = arg; ev->status = 0; //memset(ev->buf, 0, sizeof(ev->buf)); //ev->len = 0; ev->last_active = time(NULL); return; } void recvdata(int fd, int events, void *arg); void senddata(int fd, int events, void *arg); void eventadd(int efd, int events, struct myevent_s *ev) { struct epoll_event epv = {0, {0}}; int op; epv.data.ptr = ev; epv.events = ev->events = events; if (ev->status == 1) { op = EPOLL_CTL_MOD; } else { op = EPOLL_CTL_ADD; ev->status = 1; } if (epoll_ctl(efd, op, ev->fd, &epv) < 0) printf("event add failed [fd=%d], events[%d]\n", ev->fd, events); else printf("event add OK [fd=%d], op=%d, events[%0X]\n", ev->fd, op, events); return; } void eventdel(int efd, struct myevent_s *ev) { struct epoll_event epv = {0, {0}}; if (ev->status != 1) return; epv.data.ptr = ev; ev->status = 0; epoll_ctl(efd, EPOLL_CTL_DEL, ev->fd, &epv); return; } void acceptconn(int lfd, int events, void *arg) { struct sockaddr_in cin; socklen_t len = sizeof(cin); int cfd, i; if ((cfd = accept(lfd, (struct sockaddr *)&cin, &len)) == -1) { if (errno != EAGAIN && errno != EINTR) { /* 暫時不做出錯處理 */ } printf("%s: accept, %s\n", __func__, strerror(errno)); return; } do { for (i = 0; i < MAX_EVENTS; i++) { if (g_events[i].status == 0) break; } if (i == MAX_EVENTS) { printf("%s: max connect limit[%d]\n", __func__, MAX_EVENTS); break; } int flag = 0; if ((flag = fcntl(cfd, F_SETFL, O_NONBLOCK)) < 0) { printf("%s: fcntl nonblocking failed, %s\n", __func__, strerror(errno)); break; } eventset(&g_events[i], cfd, recvdata, &g_events[i]); eventadd(g_efd, EPOLLIN, &g_events[i]); } while(0); printf("new connect [%s:%d][time:%ld], pos[%d]\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), g_events[i].last_active, i); return; } void recvdata(int fd, int events, void *arg) { struct myevent_s *ev = (struct myevent_s *)arg; int len; len = recv(fd, ev->buf, sizeof(ev->buf), 0); eventdel(g_efd, ev); if (len > 0) { ev->len = len; ev->buf[len] = '\0'; printf("C[%d]:%s\n", fd, ev->buf); /* 轉換為發送事件 */ eventset(ev, fd, senddata, ev); eventadd(g_efd, EPOLLOUT, ev); } else if (len == 0) { close(ev->fd); /* ev-g_events 地址相減得到偏移元素位置 */ printf("[fd=%d] pos[%d], closed\n", fd, (int)(ev - g_events)); } else { close(ev->fd); printf("recv[fd=%d] error[%d]:%s\n", fd, errno, strerror(errno)); } return; } void senddata(int fd, int events, void *arg) { struct myevent_s *ev = (struct myevent_s *)arg; int len; len = send(fd, ev->buf, ev->len, 0); //printf("fd=%d\tev->buf=%s\ttev->len=%d\n", fd, ev->buf, ev->len); //printf("send len = %d\n", len); eventdel(g_efd, ev); if (len > 0) { printf("send[fd=%d], [%d]%s\n", fd, len, ev->buf); eventset(ev, fd, recvdata, ev); eventadd(g_efd, EPOLLIN, ev); } else { close(ev->fd); printf("send[fd=%d] error %s\n", fd, strerror(errno)); } return; } void initlistensocket(int efd, short port) { int lfd = socket(AF_INET, SOCK_STREAM, 0); fcntl(lfd, F_SETFL, O_NONBLOCK); eventset(&g_events[MAX_EVENTS], lfd, acceptconn, &g_events[MAX_EVENTS]); eventadd(efd, EPOLLIN, &g_events[MAX_EVENTS]); struct sockaddr_in sin; memset(&sin, 0, sizeof(sin)); sin.sin_family = AF_INET; sin.sin_addr.s_addr = INADDR_ANY; sin.sin_port = htons(port); bind(lfd, (struct sockaddr *)&sin, sizeof(sin)); listen(lfd, 20); return; } int main(int argc, char *argv[]) { unsigned short port = SERV_PORT; if (argc == 2) port = atoi(argv[1]); g_efd = epoll_create(MAX_EVENTS+1); if (g_efd <= 0) printf("create efd in %s err %s\n", __func__, strerror(errno)); initlistensocket(g_efd, port); /* 事件循環 */ struct epoll_event events[MAX_EVENTS+1]; printf("server running:port[%d]\n", port); int checkpos = 0, i; while (1) { /* 超時驗證，每次測試100個鏈接，不測試listenfd 當客戶端60秒內沒有和服務器通信，則關閉此客戶端鏈接 */ long now = time(NULL); for (i = 0; i < 100; i++, checkpos++) { if (checkpos == MAX_EVENTS) checkpos = 0; if (g_events[checkpos].status != 1) continue; long duration = now - g_events[checkpos].last_active; if (duration >= 60) { close(g_events[checkpos].fd); printf("[fd=%d] timeout\n", g_events[checkpos].fd); eventdel(g_efd, &g_events[checkpos]); } } /* 等待事件發生 */ int nfd = epoll_wait(g_efd, events, MAX_EVENTS+1, 1000); if (nfd < 0) { printf("epoll_wait error, exit\n"); break; } for (i = 0; i < nfd; i++) { struct myevent_s *ev = (struct myevent_s *)events[i].data.ptr; if ((events[i].events & EPOLLIN) && (ev->events & EPOLLIN)) { ev->call_back(ev->fd, events[i].events, ev->arg); } if ((events[i].events & EPOLLOUT) && (ev->events & EPOLLOUT)) { ev->call_back(ev->fd, events[i].events, ev->arg); } } } /* 退出前釋放所有資源 */ return 0; } ```