统一事件源

unievent.cpp

//统一事件源

#include <unistd.h>
#include <stdio.h>
#include <sys/epoll.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>

#define MAX_EVENT_NUMBER 1024
static int pipefd[2];

/*设置非阻塞*/
int setnonblocking(int fd)
{
    int old_option = fcntl(fd, F_GETFL);
    int new_option = old_option|O_NONBLOCK;
    fcntl(fd, F_SETFL, new_option);
    return old_option;
}

/*添加epollfd*/
void addfd(int epollfd, int fd)
{
    epoll_event event;
    event.data.fd = fd;
    event.events = EPOLLIN|EPOLLET;
    epoll_ctl(int epollfd, EPOLL_CTL_ADD, fd, &event);
    setnonblocking(fd);
}

/*信号处理函数*/
void sig_handler(int sig)
{
    /*保留原来的errno，在函数最后恢复以便函数的可重入性*/
    int save_errno = errno;
    int msg = sig;
    send(pipefd[1], (char *)&msg, 1, 0);
    errno = save_errno;
}

/*设置信号的处理函数*/
void addsig(int sig)
{
    struct sigaction sa;
    memset(&sa, '\0', sizeof(sa));
    sa.sa_handler = sig_handler;
    sa.sa_flags|=SA_RESTART;
    sigfillset(&sa.sa_mask);
    assert(sigaction(sig, &sa, NULL) != -1);
}


int main(int argc ,char **argv)
{
    if (argc < 2) {
        fprintf(stderr, "usage: %s ip port\n", argv[0]);
        return 1;
    }
    const char *ip = argv[1];
    int port = atoi(argv[2]);
    int ret = 0;
    
    struct sockaddr_in sock_addr;
    bzero(&sock_addr, sizeof(sock_addr));
    sock_addr.sin_family = AF_INET;
    sock_addr.sin_port = htons(port);
    inet_pton(AF_INET, ip, &sock_addr.sin_addr);
    
    int listenfd = socket(PF_INET, SOCK_STREAM, 0);
    assert(listenfd>=0);
    
    ret = bind(listenfd, (struct sockaddr*)&sock_addr, sizeof(sock_addr));
    assert(ret!=-1);
    
    ret = listen(listenfd, 5);
    assert(ret!=-1);
    
    epoll_event events[MAX_EVENT_NUMBER];
    int epfd = epoll_create(5);
    assert(epfd!=-1);
    addfd(epfd, listenfd);
    
    /*使用socketpair创建管道，注册pipefd[0]上的可读事件*/
    ret = socketpair(PF_UNIX, SOCK_STREAM, 0, pipefd);
    assert(ret!=-1);
    setnonblocking(pipefd[1]);
    addfd(epfd, pipefd[0]);
    
    /*设置一些信号处理函数*/
    addsig(SIGHUP);
    addsig(SIGCHLD);
    addsig(SIGTERM);
    addsig(SIGINT);
    int stop_server = 0;
    while (!stop_server) {
        int number = epoll_wait(epfd, events, MAX_EVENT_NUMBER, -1);
        if ((number<0)&&(errno!=EINTR)) {
            printf("epoll failure\n");
            break;
        }
        for (int i=0; i<number; i++) {
            int sockfd = events[i].data.fd;
            /*如果就绪的文件描述符是listenfd,则处理新连接*/
            if (sockfd == listenfd) {
                struct sockaddr_in client_addr;
                socklen_t client_addr_len = sizeof(client_addr);
                int connfd = accept(listenfd, (struct sockaddr*)&client_addr, &client_addr_len);
                addfd(epfd, connfd);
            }
            
            /*如果就绪的文件描述符是pipefd[0],则处理信号*/
            else if ((sockfd == pipefd[0]) && (events[i].events & EPOLLIN)) {
                int sig;
                char signals[1024];
                ret = recv(pipefd[0], signals, sizeof(signals), 0);
                if (ret == -1) {
                    continue;
                } else if (ret == 0) {
                    continue;
                } else {
                    /*因为每个信号值占1字节，所以按字节来逐个接收信号*/
                    for (int i=0; i<ret; ++i) {
                        switch (signals[i]) {
                            case SIGCHLD:
                            case SIGHUP:
                            {
                                continue;
                            }
                            case SIGTERM:
                            case SIGINT:
                            {
                                stop_server = 1;
                            }
                        }
                    }
                }
            }
        }
        
    }
    printf("close fds\n");
    close(listenfd);
    close(pipefd[1]);
    close(pipefd[0]);
    return 0;
}