kqueue例子[IO多路复用]

//
// Created by chenshun on 2022/3/21.
//
#include <sys/socket.h>
#include <sys/event.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
const size_t PAGE = 1024 * 16;
const int kReadEvent = 1;
const int kWriteEvent = 2;
void updateEvent(int kqFd, int fd, int events) {
    struct kevent ke;
    if (events & kReadEvent) {
        EV_SET(&ke, fd, EVFILT_READ, EV_ADD, 0, 0, 0);
        kevent(kqFd, &ke, 1, NULL, 0, NULL);
    }
    if (events & kWriteEvent) {
        EV_SET(&ke, fd, EVFILT_WRITE, EV_ADD, 0, 0, 0);
        kevent(kqFd, &ke, 1, NULL, 0, NULL);
    }
}
void delEvent(int kqFd, int fd, int events) {
    struct kevent ke;
    if (events & kReadEvent) {
        EV_SET(&ke, fd, EVFILT_READ, EV_DELETE, 0, 0, 0);
        kevent(kqFd, &ke, 1, NULL, 0, NULL);
    }
    if (events & kWriteEvent) {
        EV_SET(&ke, fd, EVFILT_WRITE, EV_DELETE, 0, 0, 0);
        kevent(kqFd, &ke, 1, NULL, 0, NULL);
    }
}
void handleAccept(int kq, int socket_fd) {
    struct sockaddr_storage sa;
    socklen_t salen = sizeof(sa);
    int client = accept(socket_fd, (struct sockaddr *) &sa, &salen);
    int flags = fcntl(client, F_GETFL, 0);
    fcntl(client, F_SETFL, flags | O_NONBLOCK);
    updateEvent(kq, client, kReadEvent);
}
void handleRead(int kq, int fd) {
    char buf[PAGE];
    size_t rr = read(fd, &buf, PAGE);
    if (rr == 0) {
        delEvent(kq, fd, kReadEvent | kWriteEvent);
        close(fd);
        return;
    }
    delEvent(kq, fd, kReadEvent);
    if (rr == 6 && !strcmp("exit\r\n", buf)) {
        write(fd, "good bye!\n", strlen("good bye!\n"));
        close(fd);
        return;
    }
    printf("receive bytes: %zu, i have receive your message: %s\n", rr, buf);
    updateEvent(kq, fd, kWriteEvent);
}
void handleWrite(int kq, int fd) {
    char *send = "i have receive your message, expect your next message\n";
    write(fd, send, strlen(send));
    delEvent(kq, fd, kWriteEvent);
    updateEvent(kq, fd, kReadEvent);
}
void loop_once(int kq, int socket_fd, int waitms) {
    struct timespec timeout;
    timeout.tv_sec = waitms / 1000;
    timeout.tv_nsec = (waitms % 1000) * 1000 * 1000;
    struct kevent *event = malloc(sizeof(struct kevent *));
    int retval = kevent(kq, NULL, 0, event, 20, &timeout);
    if (retval > 0) {
        printf("收到事件: %d 件\n", retval);
    }
    for (int i = 0; i < retval; i++) {
        struct kevent ev = event[i];
        uintptr_t fd = ev.ident;
        if (ev.filter == EVFILT_READ) {
            //处理可读时间
            if (fd == socket_fd) {
                handleAccept(kq, socket_fd);
            } else {
                handleRead(kq, (int) fd);
            }
        }
        if (ev.filter == EVFILT_WRITE) {
            //处理可写事件
            handleWrite(kq, (int) fd);
        }
    }
    free(event);
}
int main() {
    int port = 19999;
    int socket_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    struct sockaddr_in *serv_addr = malloc(sizeof(struct sockaddr_in));
    if (serv_addr == NULL) {
        printf("分配内存失败");
        exit(1);
    }
    serv_addr->sin_family = AF_INET;
    serv_addr->sin_addr.s_addr = inet_addr("127.0.0.1");
    serv_addr->sin_port = htons(port);
    //
    int on = 1;
    setsockopt(socket_fd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(on));
    int flags = fcntl(socket_fd, F_GETFL, 0);
    fcntl(socket_fd, F_SETFL, flags | O_NONBLOCK);
    if (bind(socket_fd, (struct sockaddr *) serv_addr, sizeof(struct sockaddr)) < 0) {
        printf("bind 失败!");
        exit(1);
    }
    listen(socket_fd, 20);
    printf("使用telnet 127.0.0.1 19999 来进行测试\n");
    printf("输入exit来断开TCP链接\n");
    int queue = kqueue();
    //注册
    updateEvent(queue, socket_fd, kReadEvent);
    for (;;) {
        loop_once(queue, socket_fd, 10000);
    }
    return 0;
}