# 3.2 epoll的反应堆模式实现
>epoll反应堆模式的实现-也就是libevent的实现原理。
```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表示在监听事件中，0表示不在
* last_active:记录最后一次响应时间,做超时处理
*/
struct myevent_s {
int fd; //cfd listenfd
int events; //EPOLLIN EPLLOUT
void *arg; //指向自己结构体指针
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 最后一个用于 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) {
/* 暂时不做出错处理 */
}
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);
/* 转换为发送事件 */
eventset(ev, fd, senddata, ev);
eventadd(g_efd, EPOLLOUT, ev);
}
else if (len == 0) {
close(ev->fd);
/* ev-g_events 地址相减得到偏移元素位置 */
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);
/* 事件循环 */
struct epoll_event events[MAX_EVENTS+1];
printf("server running:port[%d]\n", port);
int checkpos = 0, i;
while (1) {
/* 超时验证，每次测试100个链接，不测试listenfd 当客户端60秒内没有和服务器通信，则关闭此客户端链接 */
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]);
}
}
/* 等待事件发生 */
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);
}
}
}
/* 退出前释放所有资源 */
return 0;
}
```
- 封面
- 1 Libevent官方
- 2 epoll
- 2.1 流-IO操作-阻塞
- 2.2 解决阻塞死等待的办法
- 2.3 什么是epoll
- 2.4 epollAPI
- 2.5 触发模式
- 2.6 简单的epoll服务器
- 3 epoll和reactor
- 3.1 reactor反应堆模式
- 3.2 epoll的反应堆模式实现
- 4 event_base
- 4.1 创建event_base
- 4.2 检查event_base后端
- 4.3 释放event_base
- 4.4 event_base优先级
- 4.5 event_base和fork
- 5 事件循环event_loop
- 5.1 运行循环
- 5.2 停止循环
- 5.3 转储event_base的状态
- 6 事件event
- 6.1 创建事件
- 6.2 事件的未决和非未决
- 6.3 事件的优先级
- 6.4 检查事件状态
- 6.5 一次触发事件
- 6.6 手动激活事件
- 6.7 事件状态之间的转换
- 7 数据缓冲Bufferevent
- 7.1 回调和水位
- 7.2 延迟回调
- 7.3 bufferevent 选项标志
- 7.4 使用bufferevent
- 7.5 通用bufferevent操作
- 7.5.1 释放bufferevent操作
- 7.5.2 操作回调、水位和启用/禁用
- 7.5.3 操作bufferevent中的数据
- 7.5.4 bufferevent的清空操作
- 8 数据封装evBuffer
- 8.1 创建和释放evbuffer
- 8.2 evbuffer与线程安全
- 8.3 检查evbuffer
- 8.4 向evbuffer添加数据
- 8.5 evbuffer数据移动
- 8.6 添加数据到evbuffer前
- 8 链接监听器evconnlistener
- 8.1 创建和释放 evconnlistener
- 8.2 启用和禁用 evconnlistener
- 8.3 调整 evconnlistener 的回调函数
- 8.4 检测 evconnlistener
- 8.5 侦测错误
- 9 libevent常用设置
- 9.1 日志消息回调设置
- 9.2 致命错误回调设置
- 9.3 内存管理回调设置
- 9.4 锁和线程的设置
- 9.5 调试事件的使用
- 10 基于libevent服务器
- 10.1 Hello_World服务器(基于信号)
- 10.2 基于事件服务器
- 10.3 回显服务器
- 10.3 libevent实现http服务器