/*** 
 * sserv1.c
 *
 * echo strings sent from a client process, reply appropriately,
 * until "quit" is encountered.
 *
 * To compile: gcc -lsocket -lnsl sserv1.c -o sserv1
 *
 **/ 

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <string.h>

#define SADDRESS "mysocket"
#define BUFLEN  40

int main(int argc, char *argv[]) 
{
    struct sockaddr_un party_addr, own_addr;
    int  sockfd;
    char buf[BUFLEN];
    int  party_len;
    int  quitting;

    quitting = 1;

    /*   */
    memset(&own_addr, 0, sizeof(own_addr));
    own_addr.sun_family = AF_UNIX;
    strcpy(own_addr.sun_path, SADDRESS);

    /*  */
    if ((sockfd = socket(AF_UNIX, SOCK_DGRAM, 0)) < 0) 
    {
        printf("can't create socket\n");
        return 0;
    }

    /*  */
    unlink(own_addr.sun_path);
    if (bind(sockfd, (struct sockaddr *) &own_addr,
             sizeof(own_addr.sun_family)+ strlen(own_addr.sun_path)) < 0) 
    {
        printf("can't bind socket!");
        return 0;
    }


    /*  */
    while (1) 
    {
       /*  */
       party_len = sizeof(party_addr);
       if (recvfrom(sockfd, buf, BUFLEN, 0,(struct sockaddr *) 
                    &party_addr, &party_len) < 0) 
       {
           printf("server: error reading socket!");
           return 0;
       }

       printf("server: received from client: %s \n", buf);

       /* ? */
       quitting = (!strcmp(buf, "quit"));
       if (quitting) strcpy(buf, "quitting now!");
       else if (!strcmp(buf, "ping!")) strcpy(buf, "pong!"); 
       else strcpy(buf, "wrong string!");

       /*  */
       if (sendto(sockfd, buf, strlen(buf) + 1, 0, 
                  (struct sockaddr *) &party_addr, party_len) != strlen(buf)+1)
       {
           printf("server: error writing socket!\n");
           return 0;
       }

       if (quitting) break;
    }

    close(sockfd);
    return 0;      
}