epoll_sample.c

/*
 * epoll_sample.c
 *
 * forked from http://d.hatena.ne.jp/odz/20070507/1178558340
 *
 * compile : gcc -O3 -o epoll_sample epoll_sample.c
 * bench   : ab -n 10000 -c 50 http://localhost:8080/
 *
 * fix me :)
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/epoll.h>
#include <netinet/in.h>
#include <netdb.h>

#define SERVER_PORT "8080" /* must be _string_ */
#define MAX_EVENTS  100
#define BACKLOG     10

static int listener;
static int epfd;

static void die (const char* msg)
{
    perror(msg);
    exit(EXIT_FAILURE);
}

static void setnonblocking(int sock)
{
    int flag = fcntl(sock, F_GETFL, 0);
    fcntl(sock, F_SETFL, flag | O_NONBLOCK);
}

static int setup_socket()
{
    int sock;
    struct addrinfo *res, hints;
    int optval = 1;

    memset(&hints, 0, sizeof(struct addrinfo));
    hints.ai_family = AF_INET;
    hints.ai_flags  = AI_PASSIVE;
    hints.ai_socktype = SOCK_STREAM;

    if ((getaddrinfo(NULL, SERVER_PORT, &hints, &res) != 0))
        die("getaddrinfo");

    if ((sock = socket(res->ai_family, res->ai_socktype, 0)) < 0)
        die("socket");

    if ((setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char *)&optval, sizeof(optval))) < 0)
        die("setsockopt");

    if (bind(sock, res->ai_addr, res->ai_addrlen) < 0)
        die("bind");

    if (listen(sock, BACKLOG) < 0)
        die("listen");

    freeaddrinfo(res);

    return sock;
}

int main()
{
    struct epoll_event ev;
    struct epoll_event events[MAX_EVENTS];
    char buffer[1024];
    char res[2048];

    snprintf(res, sizeof(res),
            "HTTP/1.0 200 OK\r\n"
            "Content-Lnegth: 7\r\n"
            "Content-Type: text/plain\r\n"
            "\r\n"
            "HELLO\r\n");

    if ((epfd = epoll_create(MAX_EVENTS)) < 0)
        die ("epoll_create");

    listener = setup_socket();

    memset(&ev, 0, sizeof(ev));
    ev.events = EPOLLIN;
    ev.data.fd = listener;

    if (epoll_ctl(epfd, EPOLL_CTL_ADD, listener, &ev) < 0)
        die("epoll set insertion error");

    int i, nfd;

    while (1) {
        nfd = epoll_wait(epfd, events, MAX_EVENTS, -1);

        for (i = 0; i < nfd; i++) {
            if (events[i].data.fd == listener) {
                struct sockaddr_in client_addr;
                socklen_t client_addr_len = sizeof(client_addr);

                int client = accept(listener, (struct sockaddr *)&client_addr, &client_addr_len);
                if (client < 0) {
                    perror("accept");
                    continue;
                }

                setnonblocking(client);
                ev.events = EPOLLIN | EPOLLET;

                ev.data.fd = client;
                if(epoll_ctl(epfd, EPOLL_CTL_ADD, client, &ev) < 0)
                    die("epoll set insertion error");
            } else {
                int client = events[i].data.fd;
                int n = read(client, buffer, sizeof(buffer));

                if (n < 0) {
                    perror("read");
                    if (epoll_ctl(epfd, EPOLL_CTL_DEL, client, &ev) < 0)
                        perror("epoll delete error");
                } else if (n == 0) {
                    if (epoll_ctl(epfd, EPOLL_CTL_DEL, client, &ev) < 0)
                        perror("epoll delete error");
                } else {
                    write(client, res, (int)strlen(res));
                    if (epoll_ctl(epfd, EPOLL_CTL_DEL, client, &ev) < 0)
                        perror("epoll delete error");
                }
                shutdown(client, SHUT_RDWR);
                close(client);
            }
        }
    }

    close(epfd);
    close(listener);

    return 0;
}