OpenBSD-4.6/libexec/talkd/process.c
/* $OpenBSD: process.c,v 1.18 2006/10/18 21:23:11 deraadt Exp $ */
/*
* 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. 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 1.18 2006/10/18 21:23:11 deraadt 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 <arpa/inet.h>
#include <protocols/talkd.h>
#include <netdb.h>
#include <syslog.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <paths.h>
#include "talkd.h"
#define satosin(sa) ((struct sockaddr_in *)(sa))
void
process_request(CTL_MSG *mp, CTL_RESPONSE *rp)
{
CTL_MSG *ptr;
char *s;
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);
if (ntohs(mp->addr.sa_family) != AF_INET) {
syslog(LOG_WARNING, "Bad address, family %d",
ntohs(mp->addr.sa_family));
rp->answer = BADADDR;
return;
}
if (ntohs(mp->ctl_addr.sa_family) != AF_INET) {
syslog(LOG_WARNING, "Bad control address, family %d",
ntohs(mp->ctl_addr.sa_family));
rp->answer = BADCTLADDR;
return;
}
for (s = mp->l_name; *s; s++)
if (!isprint(*s)) {
syslog(LOG_NOTICE, "Illegal user name. Aborting");
rp->answer = FAILED;
return;
}
if (memcmp(&satosin(&rp->addr)->sin_addr,
&satosin(&mp->ctl_addr)->sin_addr,
sizeof(struct in_addr))) {
char buf1[32], buf2[32];
strlcpy(buf1, inet_ntoa(satosin(&rp->addr)->sin_addr),
sizeof(buf1));
strlcpy(buf2, inet_ntoa(satosin(&mp->ctl_addr)->sin_addr),
sizeof(buf2));
syslog(LOG_WARNING, "addresses are different, %s != %s",
buf1, buf2);
}
rp->addr.sa_family = 0;
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.sa_family = ptr->addr.sa_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);
}
void
do_announce(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, sizeof(mp->r_tty));
if (result != SUCCESS) {
rp->answer = result;
return;
}
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
*/
int
find_user(char *name, char *tty, size_t ttyl)
{
struct utmp ubuf, ubuf1;
int status;
FILE *fp;
char line[UT_LINESIZE+1];
char ftty[MAXPATHLEN];
time_t idle, now;
time(&now);
idle = INT_MAX;
if ((fp = fopen(_PATH_UTMP, "r")) == NULL) {
fprintf(stderr, "talkd: can't read %s.\n", _PATH_UTMP);
return (FAILED);
}
#define SCMPN(a, b) strncmp(a, b, sizeof(a))
status = NOT_HERE;
(void) strlcpy(ftty, _PATH_DEV, sizeof(ftty));
while (fread((char *) &ubuf, sizeof(ubuf), 1, fp) == 1)
if (SCMPN(ubuf.ut_name, name) == 0) {
if (*tty == '\0') {
/* no particular tty was requested */
struct stat statb;
memcpy(line, ubuf.ut_line, UT_LINESIZE);
line[sizeof(line)-1] = '\0';
ftty[sizeof(_PATH_DEV)-1] = '\0';
strlcat(ftty, line, sizeof(ftty));
if (stat(ftty, &statb) == 0) {
if (!(statb.st_mode & S_IWGRP)) {
if (status == NOT_HERE)
status = PERMISSION_DENIED;
} else if (now - statb.st_atime < idle) {
idle = now - statb.st_atime;
status = SUCCESS;
ubuf1 = ubuf;
}
}
} else if (SCMPN(ubuf.ut_line, tty) == 0) {
status = SUCCESS;
break;
}
}
fclose(fp);
if (*tty == '\0' && status == SUCCESS) {
memcpy(line, ubuf1.ut_line, UT_LINESIZE);
line[sizeof(line)-1] = '\0';
strlcpy(tty, line, ttyl);
}
return (status);
}