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 are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #ifndef lint 19 static char sccsid[] = "@(#)process.c 5.8 (Berkeley) 05/11/89"; 20 #endif /* not lint */ 21 22 /* 23 * process.c handles the requests, which can be of three types: 24 * ANNOUNCE - announce to a user that a talk is wanted 25 * LEAVE_INVITE - insert the request into the table 26 * LOOK_UP - look up to see if a request is waiting in 27 * in the table for the local user 28 * DELETE - delete invitation 29 */ 30 #include <sys/types.h> 31 #include <sys/stat.h> 32 #include <stdio.h> 33 #include <syslog.h> 34 #include <netdb.h> 35 #include <netinet/in.h> 36 37 #include <protocols/talkd.h> 38 #include <paths.h> 39 40 char *strcpy(); 41 CTL_MSG *find_request(); 42 CTL_MSG *find_match(); 43 44 process_request(mp, rp) 45 register CTL_MSG *mp; 46 register CTL_RESPONSE *rp; 47 { 48 register CTL_MSG *ptr; 49 extern int debug; 50 51 rp->vers = TALK_VERSION; 52 rp->type = mp->type; 53 rp->id_num = htonl(0); 54 if (mp->vers != TALK_VERSION) { 55 syslog(LOG_WARNING, "Bad protocol version %d", mp->vers); 56 rp->answer = BADVERSION; 57 return; 58 } 59 mp->id_num = ntohl(mp->id_num); 60 mp->addr.sa_family = ntohs(mp->addr.sa_family); 61 if (mp->addr.sa_family != AF_INET) { 62 syslog(LOG_WARNING, "Bad address, family %d", 63 mp->addr.sa_family); 64 rp->answer = BADADDR; 65 return; 66 } 67 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 68 if (mp->ctl_addr.sa_family != AF_INET) { 69 syslog(LOG_WARNING, "Bad control address, family %d", 70 mp->ctl_addr.sa_family); 71 rp->answer = BADCTLADDR; 72 return; 73 } 74 mp->pid = ntohl(mp->pid); 75 if (debug) 76 print_request("process_request", mp); 77 switch (mp->type) { 78 79 case ANNOUNCE: 80 do_announce(mp, rp); 81 break; 82 83 case LEAVE_INVITE: 84 ptr = find_request(mp); 85 if (ptr != (CTL_MSG *)0) { 86 rp->id_num = htonl(ptr->id_num); 87 rp->answer = SUCCESS; 88 } else 89 insert_table(mp, rp); 90 break; 91 92 case LOOK_UP: 93 ptr = find_match(mp); 94 if (ptr != (CTL_MSG *)0) { 95 rp->id_num = htonl(ptr->id_num); 96 rp->addr = ptr->addr; 97 rp->addr.sa_family = htons(ptr->addr.sa_family); 98 rp->answer = SUCCESS; 99 } else 100 rp->answer = NOT_HERE; 101 break; 102 103 case DELETE: 104 rp->answer = delete_invite(mp->id_num); 105 break; 106 107 default: 108 rp->answer = UNKNOWN_REQUEST; 109 break; 110 } 111 if (debug) 112 print_response("process_request", rp); 113 } 114 115 do_announce(mp, rp) 116 register CTL_MSG *mp; 117 CTL_RESPONSE *rp; 118 { 119 struct hostent *hp; 120 CTL_MSG *ptr; 121 int result; 122 123 /* see if the user is logged */ 124 result = find_user(mp->r_name, mp->r_tty); 125 if (result != SUCCESS) { 126 rp->answer = result; 127 return; 128 } 129 #define satosin(sa) ((struct sockaddr_in *)(sa)) 130 hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr, 131 sizeof (struct in_addr), AF_INET); 132 if (hp == (struct hostent *)0) { 133 rp->answer = MACHINE_UNKNOWN; 134 return; 135 } 136 ptr = find_request(mp); 137 if (ptr == (CTL_MSG *) 0) { 138 insert_table(mp, rp); 139 rp->answer = announce(mp, hp->h_name); 140 return; 141 } 142 if (mp->id_num > ptr->id_num) { 143 /* 144 * This is an explicit re-announce, so update the id_num 145 * field to avoid duplicates and re-announce the talk. 146 */ 147 ptr->id_num = new_id(); 148 rp->id_num = htonl(ptr->id_num); 149 rp->answer = announce(mp, hp->h_name); 150 } else { 151 /* a duplicated request, so ignore it */ 152 rp->id_num = htonl(ptr->id_num); 153 rp->answer = SUCCESS; 154 } 155 } 156 157 #include <utmp.h> 158 159 /* 160 * Search utmp for the local user 161 */ 162 find_user(name, tty) 163 char *name, *tty; 164 { 165 struct utmp ubuf; 166 int status; 167 FILE *fd; 168 struct stat statb; 169 char ftty[20]; 170 171 if ((fd = fopen(_PATH_UTMP, "r")) == NULL) { 172 fprintf(stderr, "talkd: can't read %s.\n", _PATH_UTMP); 173 return (FAILED); 174 } 175 #define SCMPN(a, b) strncmp(a, b, sizeof (a)) 176 status = NOT_HERE; 177 (void) strcpy(ftty, _PATH_DEV); 178 while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) 179 if (SCMPN(ubuf.ut_name, name) == 0) { 180 if (*tty == '\0') { 181 status = PERMISSION_DENIED; 182 /* no particular tty was requested */ 183 (void) strcpy(ftty+5, ubuf.ut_line); 184 if (stat(ftty,&statb) == 0) { 185 if (!(statb.st_mode & 020)) 186 continue; 187 (void) strcpy(tty, ubuf.ut_line); 188 status = SUCCESS; 189 break; 190 } 191 } 192 if (strcmp(ubuf.ut_line, tty) == 0) { 193 status = SUCCESS; 194 break; 195 } 196 } 197 fclose(fd); 198 return (status); 199 } 200