libev-basedserver

#include <stdio.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <string.h>
#include <stdlib.h>
#include <ev.h>
#include <pthread.h>
#include <mysql.h>
#include <unistd.h>
#include <syslog.h>
#include <signal.h>
#include <fcntl.h>

int sd;
int total_clients = 0;
int exit_dsn_flag = 0;

int setnonblock(int fd);
void accept_cb(struct ev_loop *loop, struct ev_io *watcher, int revents);
int open_evsocket(int *sd);
void read_cb(struct ev_loop *loop, struct ev_io *watcher, int revents);
void *socket_thread_start(void *x);

int setnonblock(int fd) {
    int flags;

    flags = fcntl(fd, F_GETFL);
    flags |= O_NONBLOCK;
    return fcntl(fd, F_SETFL, flags);
}

/* Accept client requests */
void accept_cb(struct ev_loop *loop, struct ev_io *watcher, int revents) {
    struct sockaddr_in client_addr;
    socklen_t client_len = sizeof (client_addr);
    int client_sd;
    //struct ev_io watch_client
    struct ev_io *w_client = (struct ev_io*) malloc(sizeof (struct ev_io));

    if (EV_ERROR & revents) {
        perror("got invalid event");
        return;
    }

    // Accept client request
    client_sd = accept(watcher->fd, (struct sockaddr *) & client_addr, &client_len);

    if (client_sd < 0) {
        perror("accept error");
        return;
    }

    total_clients++; // Increment total_clients count
    send(client_sd, "1\r\n", 3, 0);

    // Initialize and start watcher to read client requests
    ev_io_init(w_client, read_cb, client_sd, EV_READ);
    ev_io_start(loop, w_client);
}

int open_evsocket(int *sd) {
    struct sockaddr_un socket_un;
    struct ev_loop *loop = ev_default_loop(0);
    struct ev_io w_accept;
    if ((*sd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
        perror("socket error");
        return -1;
    }

    if (-1 == setnonblock(*sd)) {
        perror("echo server socket nonblock");
        exit(EXIT_FAILURE);
    }

    // Set it as unix socket
    socket_un.sun_family = AF_UNIX;
    strcpy(socket_un.sun_path, "/tmp/test.sock");

    if (-1 == bind(*sd, (struct sockaddr*) & socket_un, sizeof (socket_un.sun_family) + strlen(socket_un.sun_path))) {
        perror("echo server bind");
        exit(EXIT_FAILURE);
    }

    if (-1 == listen(*sd, 50)) {
        perror("listen");
        exit(EXIT_FAILURE);
    }
    ev_io_init(&w_accept, accept_cb, *sd, EV_READ);
    ev_io_start(loop, &w_accept);

    // Start infinite loop
    while (exit_dsn_flag == 0) {
        ev_loop(loop, 0);
    }
    pthread_exit(0);

    return (0);
}

void *socket_thread_start(void *x) {
    if (0 != open_evsocket(&sd)) {
        perror("Socket failed");
    }
    return (NULL);
}

/* Read client message */
void read_cb(struct ev_loop *loop, struct ev_io *watcher, int revents) {
    char buffer[1024];
    ssize_t readlen;
    bzero(buffer, 1024);

    if (EV_ERROR & revents) {
        perror("got invalid event");
        return;
    }

    // Receive message from client socket

    readlen = recv(watcher->fd, buffer, 1024, 0);
    syslog(LOG_INFO, "Received from socket <%d> <%s>", readlen, buffer);
    if (readlen < 1) {
        // Stop and free watchet if client socket is closing
        ev_io_stop(loop, watcher);
        free(watcher);
        total_clients--; // Decrement total_clients count
        return;
    } else {

        // The problem is here , sometimes even if send return 3 .. the communication to the socket is lost
        syslog(LOG_INFO, "Sending 1 to socket  buffer=<%s> status=%d ", buffer, send(watcher->fd, "1\r\n", 3, 0));
    }
}

int main(int argc, char **argv) {
     pthread_t sock_thread;
    openlog(argv[0], LOG_PID | LOG_CONS, LOG_MAIL);
    pthread_create(&sock_thread, NULL, socket_thread_start, NULL);
     pthread_join(sock_thread, NULL);
    return 0;
}