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 5.6 (Berkeley) 06/18/88"; 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 39 char *strcpy(); 40 CTL_MSG *find_request(); 41 CTL_MSG *find_match(); 42 43 process_request(mp, rp) 44 register CTL_MSG *mp; 45 register CTL_RESPONSE *rp; 46 { 47 register CTL_MSG *ptr; 48 extern int debug; 49 50 rp->vers = TALK_VERSION; 51 rp->type = mp->type; 52 rp->id_num = htonl(0); 53 if (mp->vers != TALK_VERSION) { 54 syslog(LOG_WARNING, "Bad protocol version %d", mp->vers); 55 rp->answer = BADVERSION; 56 return; 57 } 58 mp->id_num = ntohl(mp->id_num); 59 mp->addr.sa_family = ntohs(mp->addr.sa_family); 60 if (mp->addr.sa_family != AF_INET) { 61 syslog(LOG_WARNING, "Bad address, family %d", 62 mp->addr.sa_family); 63 rp->answer = BADADDR; 64 return; 65 } 66 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family); 67 if (mp->ctl_addr.sa_family != AF_INET) { 68 syslog(LOG_WARNING, "Bad control address, family %d", 69 mp->ctl_addr.sa_family); 70 rp->answer = BADCTLADDR; 71 return; 72 } 73 mp->pid = ntohl(mp->pid); 74 if (debug) 75 print_request("process_request", mp); 76 switch (mp->type) { 77 78 case ANNOUNCE: 79 do_announce(mp, rp); 80 break; 81 82 case LEAVE_INVITE: 83 ptr = find_request(mp); 84 if (ptr != (CTL_MSG *)0) { 85 rp->id_num = htonl(ptr->id_num); 86 rp->answer = SUCCESS; 87 } else 88 insert_table(mp, rp); 89 break; 90 91 case LOOK_UP: 92 ptr = find_match(mp); 93 if (ptr != (CTL_MSG *)0) { 94 rp->id_num = htonl(ptr->id_num); 95 rp->addr = ptr->addr; 96 rp->addr.sa_family = htons(ptr->addr.sa_family); 97 rp->answer = SUCCESS; 98 } else 99 rp->answer = NOT_HERE; 100 break; 101 102 case DELETE: 103 rp->answer = delete_invite(mp->id_num); 104 break; 105 106 default: 107 rp->answer = UNKNOWN_REQUEST; 108 break; 109 } 110 if (debug) 111 print_response("process_request", rp); 112 } 113 114 do_announce(mp, rp) 115 register CTL_MSG *mp; 116 CTL_RESPONSE *rp; 117 { 118 struct hostent *hp; 119 CTL_MSG *ptr; 120 int result; 121 122 /* see if the user is logged */ 123 result = find_user(mp->r_name, mp->r_tty); 124 if (result != SUCCESS) { 125 rp->answer = result; 126 return; 127 } 128 #define satosin(sa) ((struct sockaddr_in *)(sa)) 129 hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr, 130 sizeof (struct in_addr), AF_INET); 131 if (hp == (struct hostent *)0) { 132 rp->answer = MACHINE_UNKNOWN; 133 return; 134 } 135 ptr = find_request(mp); 136 if (ptr == (CTL_MSG *) 0) { 137 insert_table(mp, rp); 138 rp->answer = announce(mp, hp->h_name); 139 return; 140 } 141 if (mp->id_num > ptr->id_num) { 142 /* 143 * This is an explicit re-announce, so update the id_num 144 * field to avoid duplicates and re-announce the talk. 145 */ 146 ptr->id_num = new_id(); 147 rp->id_num = htonl(ptr->id_num); 148 rp->answer = announce(mp, hp->h_name); 149 } else { 150 /* a duplicated request, so ignore it */ 151 rp->id_num = htonl(ptr->id_num); 152 rp->answer = SUCCESS; 153 } 154 } 155 156 #include <utmp.h> 157 158 /* 159 * Search utmp for the local user 160 */ 161 find_user(name, tty) 162 char *name, *tty; 163 { 164 struct utmp ubuf; 165 int status; 166 FILE *fd; 167 struct stat statb; 168 char ftty[20]; 169 170 if ((fd = fopen("/etc/utmp", "r")) == NULL) { 171 perror("Can't open /etc/utmp"); 172 return (FAILED); 173 } 174 #define SCMPN(a, b) strncmp(a, b, sizeof (a)) 175 status = NOT_HERE; 176 (void) strcpy(ftty, "/dev/"); 177 while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) 178 if (SCMPN(ubuf.ut_name, name) == 0) { 179 if (*tty == '\0') { 180 status = PERMISSION_DENIED; 181 /* no particular tty was requested */ 182 (void) strcpy(ftty+5, ubuf.ut_line); 183 if (stat(ftty,&statb) == 0) { 184 if (!(statb.st_mode & 020)) 185 continue; 186 (void) strcpy(tty, ubuf.ut_line); 187 status = SUCCESS; 188 break; 189 } 190 } 191 if (strcmp(ubuf.ut_line, tty) == 0) { 192 status = SUCCESS; 193 break; 194 } 195 } 196 fclose(fd); 197 return (status); 198 } 199