[unix-history] / usr / src / libexec / talkd / process.c

/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*/

#ifndef lint
static char sccsid[] = "@(#)process.c   5.1 (Berkeley) %G%";
#endif not lint

/*
* 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"
#include <sys/stat.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);
               return;
       }
       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);
               return;
       }
       /* a duplicated request, so ignore it */
       response->id_num = ptr->id_num;
       response->answer = SUCCESS;
}

#include <utmp.h>

/*
* Search utmp for the local user
*/
find_user(name, tty)
       char *name;
       char *tty;
{
       struct utmp ubuf;
       int fd, status;
       struct stat statb;
       char ftty[20];

       if ((fd = open("/etc/utmp", 0)) == -1) {
               perror("Can't open /etc/utmp");
               return (FAILED);
       }
#define SCMPN(a, b)     strncmp(a, b, sizeof (a))
       status = NOT_HERE;
       (void) strcpy(ftty, "/dev/");
       while (read(fd, (char *) &ubuf, sizeof ubuf) == sizeof(ubuf))
               if (SCMPN(ubuf.ut_name, name) == 0) {
                       if (*tty == '\0') {
                               status = PERMISSION_DENIED;
                               /* no particular tty was requested */
                               (void) strcpy(ftty+5, ubuf.ut_line);
                               if (stat(ftty,&statb) == 0) {
                                       if (!(statb.st_mode & 02))
                                               continue;
                                       (void) strcpy(tty, ubuf.ut_line);
                                       status = SUCCESS;
                                       break;
                               }
                       }
                       if (strcmp(ubuf.ut_line, tty) == 0) {
                               status = SUCCESS;
                               break;
                       }
               }
       close(fd);
       return (status);
}