BSD 4_2 development

[unix-history] / usr / src / ucb / talk / process.c

/* $Header: process.c 1.5 83/03/28 20:16:07 moore Exp $ */

   /* process.c handles the requests, which can be of three types:

               ANNOUNCE - announce to a user that a talk is wanted

               LEAVE_INVITE - insert the request into the table
               
               LOOK_UP - look up to see if a request is waiting in
                         in the table for the local user

               DELETE - delete invitation

    */

#include "ctl.h"
char *strcpy();
CTL_MSG *find_request();
CTL_MSG *find_match();

process_request(request, response)
CTL_MSG *request;
CTL_RESPONSE *response;
{
   CTL_MSG *ptr;

   response->type = request->type;
   response->id_num = 0;

   switch (request->type) {

       case ANNOUNCE :

           do_announce(request, response);
           break;

       case LEAVE_INVITE :

           ptr = find_request(request);
           if (ptr != (CTL_MSG *) 0) {
               response->id_num = ptr->id_num;
               response->answer = SUCCESS;
           } else {
               insert_table(request, response);
           }
           break;

       case LOOK_UP :

           ptr = find_match(request);
           if (ptr != (CTL_MSG *) 0) {
               response->id_num = ptr->id_num;
               response->addr = ptr->addr;
               response->answer = SUCCESS;
           } else {
               response->answer = NOT_HERE;
           }
           break;

       case DELETE :

           response->answer = delete_invite(request->id_num);
           break;

       default :

           response->answer = UNKNOWN_REQUEST;
           break;

   }
}

struct hostent *gethostbyaddr();

do_announce(request, response)
CTL_MSG *request;
CTL_RESPONSE *response;
{
   struct hostent *hp;
   CTL_MSG *ptr;
   int result;

       /* see if the user is logged */

   result = find_user(request->r_name, request->r_tty);

   if (result != SUCCESS) {
       response->answer = result;
       return;
   }

   hp = gethostbyaddr(&request->ctl_addr.sin_addr,
                         sizeof(struct in_addr), AF_INET);

   if ( hp == (struct hostent *) 0 ) {
       response->answer = MACHINE_UNKNOWN;
       return;
   }

   ptr = find_request(request);
   if (ptr == (CTL_MSG *) 0) {
       insert_table(request,response);
       response->answer = announce(request, hp->h_name);
   } else if (request->id_num > ptr->id_num) {
           /*
            * this is an explicit re-announce, so update the id_num
            * field to avoid duplicates and re-announce the talk 
            */
       ptr->id_num = response->id_num = new_id();
       response->answer = announce(request, hp->h_name);
   } else {
           /* a duplicated request, so ignore it */
       response->id_num = ptr->id_num;
       response->answer = SUCCESS;
   }

   return;
}

#include <utmp.h>

/*
* Search utmp for the local user
*/

find_user(name, tty)
char *name;
char *tty;
{
   struct utmp ubuf;

   int fd;

   if ((fd = open("/etc/utmp", 0)) == -1) {
       print_error("Can't open /etc/utmp");
       return(FAILED);
   }

   while (read(fd, (char *) &ubuf, sizeof ubuf) == sizeof(ubuf)) {
       if (strncmp(ubuf.ut_name, name, sizeof ubuf.ut_name) == 0) {
           if (*tty == '\0') {
                   /* no particular tty was requested */
               (void) strcpy(tty, ubuf.ut_line);
               close(fd);
               return(SUCCESS);
           } else if (strcmp(ubuf.ut_line, tty) == 0) {
               close(fd);
               return(SUCCESS);
           }
       }
   }

   close(fd);
   return(NOT_HERE);
}