/*
** server.c -- a stream socket server demo
*/

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

#define MYPORT 11490    /* the port users will be connecting to */

#define BACKLOG 10     /* how many pending connections queue will hold*/

void Writen(int, void *, size_t);
void sigchld_handler(int s)
{
    wait(NULL);
}

int main(void)
{
    int sockfd, new_fd;  /* listen on sock_fd, new connection on new_fd*/
    struct sockaddr_in my_addr;    /* my address information */
    struct sockaddr_in their_addr; /* connector's address information */
    int sin_size;
    struct sigaction sa;

    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

    my_addr.sin_family = AF_INET;         /* host byte order */
    my_addr.sin_port = htons(MYPORT);     /* short, network byte order */
    my_addr.sin_addr.s_addr = INADDR_ANY; /* automatically fill with my IP */
    bzero(&(my_addr.sin_zero), 8);        /* zero the rest of the struct */

    if (bind(sockfd, (struct sockaddr *)&my_addr, 
	     sizeof(struct sockaddr)) == -1) {
        perror("bind");
        exit(1);
    }

    if (listen(sockfd, BACKLOG) == -1) {
        perror("listen");
        exit(1);
    }

    sa.sa_handler = sigchld_handler; /* reap all dead processes */
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART;
    if (sigaction(SIGCHLD, &sa, NULL) == -1) {
        perror("sigaction");
        exit(1);
    }

    while(1) {  /* main accept() loop*/
        sin_size = sizeof(struct sockaddr_in);
	printf("Calling accept...\n");
        if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, 
			     &sin_size)) == -1) { 
            perror("accept");
            continue;
        }
	printf("completed accept\n");
        printf("server: got connection from %s\n",
	       inet_ntoa(their_addr.sin_addr));

        if (!fork()) { /* this is the child process */
	    printf("I'm the child: I'll be writing to the client\n");
            close(sockfd); /* child doesn't need the listener */

	    /*            if (writen(new_fd, "Hello, world!\n", 14) == -1)
                perror("write");
	    */
            Writen(new_fd, "Hello, world!\n", 14);

            close(new_fd);
	    printf("Child is exiting\n");
            exit(0);
        }
	/* only parent gets here */
        close(new_fd);  /* parent doesn't need this */
    }

    return 0;
}