Socket programming II: using Select

tcp_server.c

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/select.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(int argc, char **argv)
{
    // socket
    int listenFd = socket(AF_INET, SOCK_STREAM, 0);
    if (listenFd < 0) {
        perror("socket");
        exit(1);
    }

    struct sockaddr_in serverAddr;
    bzero(&serverAddr, sizeof(struct sockaddr_in));
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_port = htons(atoi(argv[2]));
    serverAddr.sin_addr.s_addr = inet_addr(argv[1]);

    // bind
    if (bind(listenFd, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) < 0) {
        perror("bind");
        exit(2);
    }

    // listen
    if (listen(listenFd, 30) < 0) {
        perror("listen");
        exit(3);
    }

    struct sockaddr_in clientAddr;
    socklen_t clientAddrLen = sizeof(clientAddr);

    while (1) {
        int connFd = accept(listenFd, (struct sockaddr*)&clientAddr, &clientAddrLen);
        if (connFd < 0) {
            perror("accept");
            close(listenFd);
            exit(4);
        }

        // use select.
        char buf[1024] = {0};
        fd_set readFds;
        fd_set exceptionFds;
        FD_ZERO(&readFds);
        FD_ZERO(&exceptionFds);

        while (1) {
            // bind the connFd and fd_set.
            FD_SET(connFd, &readFds);
            FD_SET(connFd, &exceptionFds);
            int ret = select(connFd + 1, &readFds, NULL, &exceptionFds, NULL);
            if (ret < 0) {
                perror("select");
                return -1;
            }

            if (FD_ISSET(connFd, &readFds)) { //read event.
                read(connFd, buf, 1024);
                printf("recv:%s\n", buf);
            }

            if (FD_ISSET(connFd, &exceptionFds)) { //exception event.

            }

        }
        close(connFd);
    }
    close(listenFd);
    return 0;
}