#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <signal.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>

volatile int alive = 1;

void sigterm(int s) {
    printf("%d: Sigterm received...\n", getpid());
    alive = 0;
    return;
}

void sigint(int s) {
    printf("%d: Sigint received...\n", getpid());
    alive = 0;
    return;
}

void *client(void *sockvoid) {
    int cfd = (int)sockvoid;
    printf("Client thread started\n");
    pthread_detach(pthread_self());
    while(write(cfd, "Goodbye.\r\n", strlen("Goodbye.\r\n")) > 0)
        usleep(500000);
    printf("Shutting down child.\n");
    shutdown(cfd, 2);
    close(cfd);
    pthread_exit(0);
}

void *start_loop(void *arg) {
    struct sockaddr_in sa;
    int sfd, tmp;
    
    memset(&sa, 0, sizeof(sa));
    sa.sin_family = AF_INET;
    
    sfd = socket(AF_INET, SOCK_STREAM, 0);
    bind(sfd, (struct sockaddr *)&sa, sizeof(sa));
    listen(sfd, 20);
    
    tmp = sizeof(sa);
    getsockname(sfd, (struct sockaddr *)&sa, &tmp);
    printf("Bound to: %d\n", ntohs(sa.sin_port));
    
    while(alive) {
        int cfd, socklen;
        struct sockaddr_in csa;
        pthread_t client_thread;
        
        printf("Alive...\n");
        
        socklen = sizeof(csa);
        cfd = accept(sfd, (struct sockaddr *)&csa, &socklen);
        printf("Accept received: %d\n", cfd);
        if(cfd < 0) {
            printf("Error return: %d with errno %d (%s)\n", cfd, errno, strerror(errno));
        }
        pthread_create(&client_thread, NULL, client, (void *)cfd);
    }
    
    printf("Done, alive cleared.\n");
    close(sfd);
    
    return NULL;
}

int main(int argc, char **argv) {
    void *retval;
    pthread_t child;
    struct sigaction sig;
    
    memset(&sig, 0, sizeof(sig));
    
    sig.sa_handler = sigterm;
    sigaction(SIGTERM, &sig, NULL);
    sig.sa_handler = sigint;
    sigaction(SIGINT, &sig, NULL);

    printf("Creating child...\n");
    pthread_create(&child, NULL, start_loop, NULL);
    printf("Attaching to child...\n");
    pthread_join(child, &retval);
    printf("Child exited.\n");
    exit(1);
}