source: trunk/third/talk/talkd/process.c @ 17609

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
/*static char sccsid[] = "from: @(#)process.c   5.10 (Berkeley) 2/26/91";*/
static char rcsid[] = "$Id: process.c,v 1.6 2002-05-24 18:37:50 zacheiss Exp $";
#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 <sys/param.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <protocols/talkd.h>
#include <netdb.h>
#include <syslog.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_PATHS_H
#include <paths.h>
#endif
#ifndef _PATH_DEV
#define _PATH_DEV "/dev/"
#endif

CTL_MSG *find_request();
CTL_MSG *find_match();

process_request(mp, rp)
        register CTL_MSG *mp;
        register CTL_RESPONSE *rp;
{
        register CTL_MSG *ptr;
        extern int debug;

        rp->vers = TALK_VERSION;
        rp->type = mp->type;
        rp->id_num = htonl(0);
        if (mp->vers != TALK_VERSION) {
                syslog(LOG_WARNING, "Bad protocol version %d", mp->vers);
                rp->answer = BADVERSION;
                return;
        }
        mp->id_num = ntohl(mp->id_num);
        mp->addr.family = ntohs(mp->addr.family);
        if (mp->addr.family != AF_INET) {
                syslog(LOG_WARNING, "Bad address, family %d",
                    mp->addr.family);
                rp->answer = BADADDR;
                return;
        }
        mp->ctl_addr.family = ntohs(mp->ctl_addr.family);
        if (mp->ctl_addr.family != AF_INET) {
                syslog(LOG_WARNING, "Bad control address, family %d",
                    mp->ctl_addr.family);
                rp->answer = BADCTLADDR;
                return;
        }
        mp->pid = ntohl(mp->pid);
        if (debug)
                print_request("process_request", mp);
        switch (mp->type) {

        case ANNOUNCE:
                do_announce(mp, rp);
                break;

        case LEAVE_INVITE:
                ptr = find_request(mp);
                if (ptr != (CTL_MSG *)0) {
                        rp->id_num = htonl(ptr->id_num);
                        rp->answer = SUCCESS;
                } else
                        insert_table(mp, rp);
                break;

        case LOOK_UP:
                ptr = find_match(mp);
                if (ptr != (CTL_MSG *)0) {
                        rp->id_num = htonl(ptr->id_num);
                        rp->addr = ptr->addr;
                        rp->addr.family = htons(ptr->addr.family);
                        rp->answer = SUCCESS;
                } else
                        rp->answer = NOT_HERE;
                break;

        case DELETE:
                rp->answer = delete_invite(mp->id_num);
                break;

        default:
                rp->answer = UNKNOWN_REQUEST;
                break;
        }
        if (debug)
                print_response("process_request", rp);
}

do_announce(mp, rp)
        register CTL_MSG *mp;
        CTL_RESPONSE *rp;
{
        struct hostent *hp;
        CTL_MSG *ptr;
        int result;

        /* see if the user is logged */
        result = find_user(mp->r_name, mp->r_tty);
        if (result != SUCCESS) {
                rp->answer = result;
                return;
        }
#define satosin(sa)     ((struct sockaddr_in *)(sa))
        hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr,
                sizeof (struct in_addr), AF_INET);
        if (hp == (struct hostent *)0) {
                rp->answer = MACHINE_UNKNOWN;
                return;
        }
        ptr = find_request(mp);
        if (ptr == (CTL_MSG *) 0) {
                insert_table(mp, rp);
                rp->answer = announce(mp, hp->h_name);
                return;
        }
        if (mp->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 = new_id();
                rp->id_num = htonl(ptr->id_num);
                rp->answer = announce(mp, hp->h_name);
        } else {
                /* a duplicated request, so ignore it */
                rp->id_num = htonl(ptr->id_num);
                rp->answer = SUCCESS;
        }
}

#include <utmp.h>

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

#define SCMPN(a, b)     strncmp(a, b, sizeof (a))
        status = NOT_HERE;
        (void) strcpy(ftty, _PATH_DEV);
        while ((uptr = getutent()) != NULL) {
#ifdef USER_PROCESS
                if (uptr->ut_type != USER_PROCESS)
                        continue;
#endif
                if (SCMPN(uptr->ut_name, name) == 0) {
                        if (*tty == '\0') {
                                status = PERMISSION_DENIED;
                                /* no particular tty was requested */
                                (void) strcpy(ftty+5, uptr->ut_line);
                                if (stat(ftty,&statb) == 0) {
                                        if (!(statb.st_mode & 020))
                                                continue;
                                        (void) strcpy(tty, uptr->ut_line);
                                        status = SUCCESS;
                                        break;
                                }
                        }
                        if (strcmp(uptr->ut_line, tty) == 0) {
                                status = SUCCESS;
                                break;
                        }
                }
        }
        endutent();
        return (status);
}