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 char copyright[] = 20 "@(#) Copyright (c) 1983 Regents of the University of California.\n\ 21 All rights reserved.\n"; 22 #endif /* not lint */ 23 24 #ifndef lint 25 static char sccsid[] = "@(#)lpd.c 5.7 (Berkeley) 05/11/89"; 26 #endif /* not lint */ 27 28 /* 29 * lpd -- line printer daemon. 30 * 31 * Listen for a connection and perform the requested operation. 32 * Operations are: 33 * \1printer\n 34 * check the queue for jobs and print any found. 35 * \2printer\n 36 * receive a job from another machine and queue it. 37 * \3printer [users ...] [jobs ...]\n 38 * return the current state of the queue (short form). 39 * \4printer [users ...] [jobs ...]\n 40 * return the current state of the queue (long form). 41 * \5printer person [users ...] [jobs ...]\n 42 * remove jobs from the queue. 43 * 44 * Strategy to maintain protected spooling area: 45 * 1. Spooling area is writable only by daemon and spooling group 46 * 2. lpr runs setuid root and setgrp spooling group; it uses 47 * root to access any file it wants (verifying things before 48 * with an access call) and group id to know how it should 49 * set up ownership of files in the spooling area. 50 * 3. Files in spooling area are owned by root, group spooling 51 * group, with mode 660. 52 * 4. lpd, lpq and lprm run setuid daemon and setgrp spooling group to 53 * access files and printer. Users can't get to anything 54 * w/o help of lpq and lprm programs. 55 */ 56 57 #include "lp.h" 58 #include "pathnames.h" 59 60 int lflag; /* log requests flag */ 61 62 int reapchild(); 63 int mcleanup(); 64 65 main(argc, argv) 66 int argc; 67 char **argv; 68 { 69 int f, funix, finet, options, defreadfds, fromlen; 70 struct sockaddr_un sun, fromunix; 71 struct sockaddr_in sin, frominet; 72 int omask, lfd; 73 74 gethostname(host, sizeof(host)); 75 name = argv[0]; 76 77 while (--argc > 0) { 78 argv++; 79 if (argv[0][0] == '-') 80 switch (argv[0][1]) { 81 case 'd': 82 options |= SO_DEBUG; 83 break; 84 case 'l': 85 lflag++; 86 break; 87 } 88 } 89 90 #ifndef DEBUG 91 /* 92 * Set up standard environment by detaching from the parent. 93 */ 94 if (fork()) 95 exit(0); 96 for (f = 0; f < 5; f++) 97 (void) close(f); 98 (void) open(_PATH_DEVNULL, O_RDONLY); 99 (void) open(_PATH_DEVNULL, O_WRONLY); 100 (void) dup(1); 101 f = open(_PATH_TTY, O_RDWR); 102 if (f > 0) { 103 ioctl(f, TIOCNOTTY, 0); 104 (void) close(f); 105 } 106 #endif 107 108 openlog("lpd", LOG_PID, LOG_LPR); 109 (void) umask(0); 110 lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT, 0644); 111 if (lfd < 0) { 112 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 113 exit(1); 114 } 115 if (flock(lfd, LOCK_EX|LOCK_NB) < 0) { 116 if (errno == EWOULDBLOCK) /* active deamon present */ 117 exit(0); 118 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 119 exit(1); 120 } 121 ftruncate(lfd, 0); 122 /* 123 * write process id for others to know 124 */ 125 sprintf(line, "%u\n", getpid()); 126 f = strlen(line); 127 if (write(lfd, line, f) != f) { 128 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 129 exit(1); 130 } 131 signal(SIGCHLD, reapchild); 132 /* 133 * Restart all the printers. 134 */ 135 startup(); 136 (void) unlink(_PATH_SOCKETNAME); 137 funix = socket(AF_UNIX, SOCK_STREAM, 0); 138 if (funix < 0) { 139 syslog(LOG_ERR, "socket: %m"); 140 exit(1); 141 } 142 #define mask(s) (1 << ((s) - 1)) 143 omask = sigblock(mask(SIGHUP)|mask(SIGINT)|mask(SIGQUIT)|mask(SIGTERM)); 144 signal(SIGHUP, mcleanup); 145 signal(SIGINT, mcleanup); 146 signal(SIGQUIT, mcleanup); 147 signal(SIGTERM, mcleanup); 148 sun.sun_family = AF_UNIX; 149 strcpy(sun.sun_path, _PATH_SOCKETNAME); 150 if (bind(funix, &sun, strlen(sun.sun_path) + 2) < 0) { 151 syslog(LOG_ERR, "ubind: %m"); 152 exit(1); 153 } 154 sigsetmask(omask); 155 defreadfds = 1 << funix; 156 listen(funix, 5); 157 finet = socket(AF_INET, SOCK_STREAM, 0); 158 if (finet >= 0) { 159 struct servent *sp; 160 161 if (options & SO_DEBUG) 162 if (setsockopt(finet, SOL_SOCKET, SO_DEBUG, 0, 0) < 0) { 163 syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m"); 164 mcleanup(); 165 } 166 sp = getservbyname("printer", "tcp"); 167 if (sp == NULL) { 168 syslog(LOG_ERR, "printer/tcp: unknown service"); 169 mcleanup(); 170 } 171 sin.sin_family = AF_INET; 172 sin.sin_port = sp->s_port; 173 if (bind(finet, &sin, sizeof(sin), 0) < 0) { 174 syslog(LOG_ERR, "bind: %m"); 175 mcleanup(); 176 } 177 defreadfds |= 1 << finet; 178 listen(finet, 5); 179 } 180 /* 181 * Main loop: accept, do a request, continue. 182 */ 183 for (;;) { 184 int domain, nfds, s, readfds = defreadfds; 185 186 nfds = select(20, &readfds, 0, 0, 0); 187 if (nfds <= 0) { 188 if (nfds < 0 && errno != EINTR) 189 syslog(LOG_WARNING, "select: %m"); 190 continue; 191 } 192 if (readfds & (1 << funix)) { 193 domain = AF_UNIX, fromlen = sizeof(fromunix); 194 s = accept(funix, &fromunix, &fromlen); 195 } else if (readfds & (1 << finet)) { 196 domain = AF_INET, fromlen = sizeof(frominet); 197 s = accept(finet, &frominet, &fromlen); 198 } 199 if (s < 0) { 200 if (errno != EINTR) 201 syslog(LOG_WARNING, "accept: %m"); 202 continue; 203 } 204 if (fork() == 0) { 205 signal(SIGCHLD, SIG_IGN); 206 signal(SIGHUP, SIG_IGN); 207 signal(SIGINT, SIG_IGN); 208 signal(SIGQUIT, SIG_IGN); 209 signal(SIGTERM, SIG_IGN); 210 (void) close(funix); 211 (void) close(finet); 212 dup2(s, 1); 213 (void) close(s); 214 if (domain == AF_INET) 215 chkhost(&frominet); 216 doit(); 217 exit(0); 218 } 219 (void) close(s); 220 } 221 } 222 223 reapchild() 224 { 225 union wait status; 226 227 while (wait3(&status, WNOHANG, 0) > 0) 228 ; 229 } 230 231 mcleanup() 232 { 233 if (lflag) 234 syslog(LOG_INFO, "exiting"); 235 unlink(_PATH_SOCKETNAME); 236 exit(0); 237 } 238 239 /* 240 * Stuff for handling job specifications 241 */ 242 char *user[MAXUSERS]; /* users to process */ 243 int users; /* # of users in user array */ 244 int requ[MAXREQUESTS]; /* job number of spool entries */ 245 int requests; /* # of spool requests */ 246 char *person; /* name of person doing lprm */ 247 248 char fromb[32]; /* buffer for client's machine name */ 249 char cbuf[BUFSIZ]; /* command line buffer */ 250 char *cmdnames[] = { 251 "null", 252 "printjob", 253 "recvjob", 254 "displayq short", 255 "displayq long", 256 "rmjob" 257 }; 258 259 doit() 260 { 261 register char *cp; 262 register int n; 263 264 for (;;) { 265 cp = cbuf; 266 do { 267 if (cp >= &cbuf[sizeof(cbuf) - 1]) 268 fatal("Command line too long"); 269 if ((n = read(1, cp, 1)) != 1) { 270 if (n < 0) 271 fatal("Lost connection"); 272 return; 273 } 274 } while (*cp++ != '\n'); 275 *--cp = '\0'; 276 cp = cbuf; 277 if (lflag) { 278 if (*cp >= '\1' && *cp <= '\5') 279 syslog(LOG_INFO, "%s requests %s %s", 280 from, cmdnames[*cp], cp+1); 281 else 282 syslog(LOG_INFO, "bad request (%d) from %s", 283 *cp, from); 284 } 285 switch (*cp++) { 286 case '\1': /* check the queue and print any jobs there */ 287 printer = cp; 288 printjob(); 289 break; 290 case '\2': /* receive files to be queued */ 291 printer = cp; 292 recvjob(); 293 break; 294 case '\3': /* display the queue (short form) */ 295 case '\4': /* display the queue (long form) */ 296 printer = cp; 297 while (*cp) { 298 if (*cp != ' ') { 299 cp++; 300 continue; 301 } 302 *cp++ = '\0'; 303 while (isspace(*cp)) 304 cp++; 305 if (*cp == '\0') 306 break; 307 if (isdigit(*cp)) { 308 if (requests >= MAXREQUESTS) 309 fatal("Too many requests"); 310 requ[requests++] = atoi(cp); 311 } else { 312 if (users >= MAXUSERS) 313 fatal("Too many users"); 314 user[users++] = cp; 315 } 316 } 317 displayq(cbuf[0] - '\3'); 318 exit(0); 319 case '\5': /* remove a job from the queue */ 320 printer = cp; 321 while (*cp && *cp != ' ') 322 cp++; 323 if (!*cp) 324 break; 325 *cp++ = '\0'; 326 person = cp; 327 while (*cp) { 328 if (*cp != ' ') { 329 cp++; 330 continue; 331 } 332 *cp++ = '\0'; 333 while (isspace(*cp)) 334 cp++; 335 if (*cp == '\0') 336 break; 337 if (isdigit(*cp)) { 338 if (requests >= MAXREQUESTS) 339 fatal("Too many requests"); 340 requ[requests++] = atoi(cp); 341 } else { 342 if (users >= MAXUSERS) 343 fatal("Too many users"); 344 user[users++] = cp; 345 } 346 } 347 rmjob(); 348 break; 349 } 350 fatal("Illegal service request"); 351 } 352 } 353 354 /* 355 * Make a pass through the printcap database and start printing any 356 * files left from the last time the machine went down. 357 */ 358 startup() 359 { 360 char buf[BUFSIZ]; 361 register char *cp; 362 int pid; 363 364 printer = buf; 365 366 /* 367 * Restart the daemons. 368 */ 369 while (getprent(buf) > 0) { 370 for (cp = buf; *cp; cp++) 371 if (*cp == '|' || *cp == ':') { 372 *cp = '\0'; 373 break; 374 } 375 if ((pid = fork()) < 0) { 376 syslog(LOG_WARNING, "startup: cannot fork"); 377 mcleanup(); 378 } 379 if (!pid) { 380 endprent(); 381 printjob(); 382 } 383 } 384 } 385 386 #define DUMMY ":nobody::" 387 388 /* 389 * Check to see if the from host has access to the line printer. 390 */ 391 chkhost(f) 392 struct sockaddr_in *f; 393 { 394 register struct hostent *hp; 395 register FILE *hostf; 396 register char *cp, *sp; 397 char ahost[50]; 398 int first = 1; 399 extern char *inet_ntoa(); 400 int baselen = -1; 401 402 f->sin_port = ntohs(f->sin_port); 403 if (f->sin_family != AF_INET || f->sin_port >= IPPORT_RESERVED) 404 fatal("Malformed from address"); 405 hp = gethostbyaddr(&f->sin_addr, sizeof(struct in_addr), f->sin_family); 406 if (hp == 0) 407 fatal("Host name for your address (%s) unknown", 408 inet_ntoa(f->sin_addr)); 409 410 strcpy(fromb, hp->h_name); 411 from = fromb; 412 if (!strcmp(from, host)) 413 return; 414 415 sp = fromb; 416 cp = ahost; 417 while (*sp) { 418 if (*sp == '.') { 419 if (baselen == -1) 420 baselen = sp - fromb; 421 *cp++ = *sp++; 422 } else { 423 *cp++ = isupper(*sp) ? tolower(*sp++) : *sp++; 424 } 425 } 426 *cp = '\0'; 427 hostf = fopen(_PATH_HOSTSEQUIV, "r"); 428 again: 429 if (hostf) { 430 if (!_validuser(hostf, ahost, DUMMY, DUMMY, baselen)) { 431 (void) fclose(hostf); 432 return; 433 } 434 (void) fclose(hostf); 435 } 436 if (first == 1) { 437 first = 0; 438 hostf = fopen(_PATH_HOSTSLPD, "r"); 439 goto again; 440 } 441 fatal("Your host does not have line printer access"); 442 } 443