1 /*
2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * @(#)process.c 8.2 (Berkeley) 11/16/93
30 * $FreeBSD: src/libexec/talkd/process.c,v 1.9 1999/08/28 00:10:16 peter Exp $
31 */
32
33 /*
34 * process.c handles the requests, which can be of three types:
35 * ANNOUNCE - announce to a user that a talk is wanted
36 * LEAVE_INVITE - insert the request into the table
37 * LOOK_UP - look up to see if a request is waiting in
38 * in the table for the local user
39 * DELETE - delete invitation
40 */
41 #include <sys/param.h>
42 #include <sys/stat.h>
43 #include <sys/socket.h>
44 #include <netinet/in.h>
45 #include <protocols/talkd.h>
46 #include <ctype.h>
47 #include <err.h>
48 #include <netdb.h>
49 #include <paths.h>
50 #include <stdio.h>
51 #include <string.h>
52 #include <syslog.h>
53 #include <utmpx.h>
54
55 #include "extern.h"
56
57 extern int debug;
58
59 void
process_request(CTL_MSG * mp,CTL_RESPONSE * rp)60 process_request(CTL_MSG *mp, CTL_RESPONSE *rp)
61 {
62 CTL_MSG *ptr;
63 char *s;
64
65 rp->vers = TALK_VERSION;
66 rp->type = mp->type;
67 rp->id_num = htonl(0);
68 if (mp->vers != TALK_VERSION) {
69 syslog(LOG_WARNING, "bad protocol version %d", mp->vers);
70 rp->answer = BADVERSION;
71 return;
72 }
73 mp->id_num = ntohl(mp->id_num);
74 mp->addr.sa_family = ntohs(mp->addr.sa_family);
75 if (mp->addr.sa_family != AF_INET) {
76 syslog(LOG_WARNING, "bad address, family %d",
77 mp->addr.sa_family);
78 rp->answer = BADADDR;
79 return;
80 }
81 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
82 if (mp->ctl_addr.sa_family != AF_INET) {
83 syslog(LOG_WARNING, "bad control address, family %d",
84 mp->ctl_addr.sa_family);
85 rp->answer = BADCTLADDR;
86 return;
87 }
88 for (s = mp->l_name; *s; s++)
89 if (!isprint(*s)) {
90 syslog(LOG_NOTICE, "illegal user name. Aborting");
91 rp->answer = FAILED;
92 return;
93 }
94 mp->pid = ntohl(mp->pid);
95 if (debug)
96 print_request("process_request", mp);
97 switch (mp->type) {
98
99 case ANNOUNCE:
100 do_announce(mp, rp);
101 break;
102
103 case LEAVE_INVITE:
104 ptr = find_request(mp);
105 if (ptr != NULL) {
106 rp->id_num = htonl(ptr->id_num);
107 rp->answer = SUCCESS;
108 } else
109 insert_table(mp, rp);
110 break;
111
112 case LOOK_UP:
113 ptr = find_match(mp);
114 if (ptr != NULL) {
115 rp->id_num = htonl(ptr->id_num);
116 rp->addr = ptr->addr;
117 rp->addr.sa_family = htons(ptr->addr.sa_family);
118 rp->answer = SUCCESS;
119 } else
120 rp->answer = NOT_HERE;
121 break;
122
123 case DELETE:
124 rp->answer = delete_invite(mp->id_num);
125 break;
126
127 default:
128 rp->answer = UNKNOWN_REQUEST;
129 break;
130 }
131 if (debug)
132 print_response("process_request", rp);
133 }
134
135 void
do_announce(CTL_MSG * mp,CTL_RESPONSE * rp)136 do_announce(CTL_MSG *mp, CTL_RESPONSE *rp)
137 {
138 struct hostent *hp;
139 CTL_MSG *ptr;
140 int result;
141
142 /* see if the user is logged */
143 result = find_user(mp->r_name, mp->r_tty, sizeof(mp->r_tty));
144 if (result != SUCCESS) {
145 rp->answer = result;
146 return;
147 }
148 #define satosin(sa) ((struct sockaddr_in *)(void *)(sa))
149 hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr,
150 sizeof (struct in_addr), AF_INET);
151 if (hp == NULL) {
152 rp->answer = MACHINE_UNKNOWN;
153 return;
154 }
155 ptr = find_request(mp);
156 if (ptr == NULL) {
157 insert_table(mp, rp);
158 rp->answer = announce(mp, hp->h_name);
159 return;
160 }
161 if (mp->id_num > ptr->id_num) {
162 /*
163 * This is an explicit re-announce, so update the id_num
164 * field to avoid duplicates and re-announce the talk.
165 */
166 ptr->id_num = new_id();
167 rp->id_num = htonl(ptr->id_num);
168 rp->answer = announce(mp, hp->h_name);
169 } else {
170 /* a duplicated request, so ignore it */
171 rp->id_num = htonl(ptr->id_num);
172 rp->answer = SUCCESS;
173 }
174 }
175
176 /*
177 * Search utmpx for the local user
178 */
179 int
find_user(const char * name,char * tty,size_t ttylen)180 find_user(const char *name, char *tty, size_t ttylen)
181 {
182 struct utmpx *ut; /* avoid gcc warnings */
183 int status;
184 struct stat statb;
185 time_t best;
186 char ftty[sizeof(_PATH_DEV) + _UTX_LINESIZE];
187
188 if (ttylen > sizeof(ftty))
189 ttylen = sizeof(ftty);
190
191 best = 0;
192 status = NOT_HERE;
193 strlcpy(ftty, _PATH_DEV, sizeof(ftty));
194 setutxent();
195 while ((ut = getutxent()) != NULL) {
196 if (ut->ut_type != USER_PROCESS)
197 continue;
198 if (strncmp(ut->ut_name, name, sizeof(ut->ut_name)) != 0)
199 continue;
200 if (*tty == '\0' || best != 0) {
201 if (best == 0)
202 status = PERMISSION_DENIED;
203 /* no particular tty was requested */
204 strlcat(ftty, ut->ut_line, sizeof(ftty));
205 if (stat(ftty, &statb) == 0) {
206 if (!(statb.st_mode & 020))
207 continue;
208 if (statb.st_atime > best) {
209 best = statb.st_atime;
210 strlcpy(tty, ut->ut_line, ttylen);
211 status = SUCCESS;
212 continue;
213 }
214 }
215 }
216 if (strcmp(ut->ut_line, tty) == 0) {
217 status = SUCCESS;
218 break;
219 }
220 }
221 endutxent();
222
223 return (status);
224 }
225