| 1 | /* |
| 2 | * Copyright (c) 1983 Regents of the University of California. |
| 3 | * 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. All advertising materials mentioning features or use of this software |
| 14 | * must display the following acknowledgement: |
| 15 | * This product includes software developed by the University of |
| 16 | * California, Berkeley and its contributors. |
| 17 | * 4. Neither the name of the University nor the names of its contributors |
| 18 | * may be used to endorse or promote products derived from this software |
| 19 | * without specific prior written permission. |
| 20 | * |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 31 | * SUCH DAMAGE. |
| 32 | */ |
| 33 | |
| 34 | #ifndef lint |
| 35 | static char sccsid[] = "@(#)process.c 5.10 (Berkeley) 2/26/91"; |
| 36 | #endif /* not lint */ |
| 37 | |
| 38 | /* |
| 39 | * process.c handles the requests, which can be of three types: |
| 40 | * ANNOUNCE - announce to a user that a talk is wanted |
| 41 | * LEAVE_INVITE - insert the request into the table |
| 42 | * LOOK_UP - look up to see if a request is waiting in |
| 43 | * in the table for the local user |
| 44 | * DELETE - delete invitation |
| 45 | */ |
| 46 | #include <sys/param.h> |
| 47 | #include <sys/stat.h> |
| 48 | #include <sys/socket.h> |
| 49 | #include <netinet/in.h> |
| 50 | #include <protocols/talkd.h> |
| 51 | #include <netdb.h> |
| 52 | #include <syslog.h> |
| 53 | #include <stdio.h> |
| 54 | #include <string.h> |
| 55 | #include <paths.h> |
| 56 | |
| 57 | CTL_MSG *find_request(); |
| 58 | CTL_MSG *find_match(); |
| 59 | |
| 60 | process_request(mp, rp) |
| 61 | register CTL_MSG *mp; |
| 62 | register CTL_RESPONSE *rp; |
| 63 | { |
| 64 | register CTL_MSG *ptr; |
| 65 | extern int debug; |
| 66 | |
| 67 | rp->vers = TALK_VERSION; |
| 68 | rp->type = mp->type; |
| 69 | rp->id_num = htonl(0); |
| 70 | if (mp->vers != TALK_VERSION) { |
| 71 | syslog(LOG_WARNING, "Bad protocol version %d", mp->vers); |
| 72 | rp->answer = BADVERSION; |
| 73 | return; |
| 74 | } |
| 75 | mp->id_num = ntohl(mp->id_num); |
| 76 | mp->addr.sa_family = ntohs(mp->addr.sa_family); |
| 77 | if (mp->addr.sa_family != AF_INET) { |
| 78 | syslog(LOG_WARNING, "Bad address, family %d", |
| 79 | mp->addr.sa_family); |
| 80 | rp->answer = BADADDR; |
| 81 | return; |
| 82 | } |
| 83 | mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); |
| 84 | if (mp->ctl_addr.sa_family != AF_INET) { |
| 85 | syslog(LOG_WARNING, "Bad control address, family %d", |
| 86 | mp->ctl_addr.sa_family); |
| 87 | rp->answer = BADCTLADDR; |
| 88 | return; |
| 89 | } |
| 90 | mp->pid = ntohl(mp->pid); |
| 91 | if (debug) |
| 92 | print_request("process_request", mp); |
| 93 | switch (mp->type) { |
| 94 | |
| 95 | case ANNOUNCE: |
| 96 | do_announce(mp, rp); |
| 97 | break; |
| 98 | |
| 99 | case LEAVE_INVITE: |
| 100 | ptr = find_request(mp); |
| 101 | if (ptr != (CTL_MSG *)0) { |
| 102 | rp->id_num = htonl(ptr->id_num); |
| 103 | rp->answer = SUCCESS; |
| 104 | } else |
| 105 | insert_table(mp, rp); |
| 106 | break; |
| 107 | |
| 108 | case LOOK_UP: |
| 109 | ptr = find_match(mp); |
| 110 | if (ptr != (CTL_MSG *)0) { |
| 111 | rp->id_num = htonl(ptr->id_num); |
| 112 | rp->addr = ptr->addr; |
| 113 | rp->addr.sa_family = htons(ptr->addr.sa_family); |
| 114 | rp->answer = SUCCESS; |
| 115 | } else |
| 116 | rp->answer = NOT_HERE; |
| 117 | break; |
| 118 | |
| 119 | case DELETE: |
| 120 | rp->answer = delete_invite(mp->id_num); |
| 121 | break; |
| 122 | |
| 123 | default: |
| 124 | rp->answer = UNKNOWN_REQUEST; |
| 125 | break; |
| 126 | } |
| 127 | if (debug) |
| 128 | print_response("process_request", rp); |
| 129 | } |
| 130 | |
| 131 | do_announce(mp, rp) |
| 132 | register CTL_MSG *mp; |
| 133 | CTL_RESPONSE *rp; |
| 134 | { |
| 135 | struct hostent *hp; |
| 136 | CTL_MSG *ptr; |
| 137 | int result; |
| 138 | |
| 139 | /* see if the user is logged */ |
| 140 | result = find_user(mp->r_name, mp->r_tty); |
| 141 | if (result != SUCCESS) { |
| 142 | rp->answer = result; |
| 143 | return; |
| 144 | } |
| 145 | #define satosin(sa) ((struct sockaddr_in *)(sa)) |
| 146 | hp = gethostbyaddr((char *)&satosin(&mp->ctl_addr)->sin_addr, |
| 147 | sizeof (struct in_addr), AF_INET); |
| 148 | if (hp == (struct hostent *)0) { |
| 149 | rp->answer = MACHINE_UNKNOWN; |
| 150 | return; |
| 151 | } |
| 152 | ptr = find_request(mp); |
| 153 | if (ptr == (CTL_MSG *) 0) { |
| 154 | insert_table(mp, rp); |
| 155 | rp->answer = announce(mp, hp->h_name); |
| 156 | return; |
| 157 | } |
| 158 | if (mp->id_num > ptr->id_num) { |
| 159 | /* |
| 160 | * This is an explicit re-announce, so update the id_num |
| 161 | * field to avoid duplicates and re-announce the talk. |
| 162 | */ |
| 163 | ptr->id_num = new_id(); |
| 164 | rp->id_num = htonl(ptr->id_num); |
| 165 | rp->answer = announce(mp, hp->h_name); |
| 166 | } else { |
| 167 | /* a duplicated request, so ignore it */ |
| 168 | rp->id_num = htonl(ptr->id_num); |
| 169 | rp->answer = SUCCESS; |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | #include <utmp.h> |
| 174 | |
| 175 | /* |
| 176 | * Search utmp for the local user |
| 177 | */ |
| 178 | find_user(name, tty) |
| 179 | char *name, *tty; |
| 180 | { |
| 181 | struct utmp ubuf; |
| 182 | int status; |
| 183 | FILE *fd; |
| 184 | struct stat statb; |
| 185 | char ftty[20]; |
| 186 | |
| 187 | if ((fd = fopen(_PATH_UTMP, "r")) == NULL) { |
| 188 | fprintf(stderr, "talkd: can't read %s.\n", _PATH_UTMP); |
| 189 | return (FAILED); |
| 190 | } |
| 191 | #define SCMPN(a, b) strncmp(a, b, sizeof (a)) |
| 192 | status = NOT_HERE; |
| 193 | (void) strcpy(ftty, _PATH_DEV); |
| 194 | while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) |
| 195 | if (SCMPN(ubuf.ut_name, name) == 0) { |
| 196 | if (*tty == '\0') { |
| 197 | status = PERMISSION_DENIED; |
| 198 | /* no particular tty was requested */ |
| 199 | (void) strcpy(ftty+5, ubuf.ut_line); |
| 200 | if (stat(ftty,&statb) == 0) { |
| 201 | if (!(statb.st_mode & 020)) |
| 202 | continue; |
| 203 | (void) strcpy(tty, ubuf.ut_line); |
| 204 | status = SUCCESS; |
| 205 | break; |
| 206 | } |
| 207 | } |
| 208 | if (strcmp(ubuf.ut_line, tty) == 0) { |
| 209 | status = SUCCESS; |
| 210 | break; |
| 211 | } |
| 212 | } |
| 213 | fclose(fd); |
| 214 | return (status); |
| 215 | } |