lpd.c revision 1.9
1 /* $NetBSD: lpd.c,v 1.9 1996/12/09 09:57:45 mrg Exp $ */ 2 3 /* 4 * Copyright (c) 1983, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 static char copyright[] = 39 "@(#) Copyright (c) 1983, 1993, 1994\n\ 40 The Regents of the University of California. All rights reserved.\n"; 41 #endif /* not lint */ 42 43 #ifndef lint 44 static char sccsid[] = "@(#)lpd.c 8.4 (Berkeley) 4/17/94"; 45 #endif /* not lint */ 46 47 /* 48 * lpd -- line printer daemon. 49 * 50 * Listen for a connection and perform the requested operation. 51 * Operations are: 52 * \1printer\n 53 * check the queue for jobs and print any found. 54 * \2printer\n 55 * receive a job from another machine and queue it. 56 * \3printer [users ...] [jobs ...]\n 57 * return the current state of the queue (short form). 58 * \4printer [users ...] [jobs ...]\n 59 * return the current state of the queue (long form). 60 * \5printer person [users ...] [jobs ...]\n 61 * remove jobs from the queue. 62 * 63 * Strategy to maintain protected spooling area: 64 * 1. Spooling area is writable only by daemon and spooling group 65 * 2. lpr runs setuid root and setgrp spooling group; it uses 66 * root to access any file it wants (verifying things before 67 * with an access call) and group id to know how it should 68 * set up ownership of files in the spooling area. 69 * 3. Files in spooling area are owned by root, group spooling 70 * group, with mode 660. 71 * 4. lpd, lpq and lprm run setuid daemon and setgrp spooling group to 72 * access files and printer. Users can't get to anything 73 * w/o help of lpq and lprm programs. 74 */ 75 76 #include <sys/param.h> 77 #include <sys/wait.h> 78 #include <sys/types.h> 79 #include <sys/socket.h> 80 #include <sys/un.h> 81 #include <sys/stat.h> 82 #include <netinet/in.h> 83 84 #include <netdb.h> 85 #include <unistd.h> 86 #include <syslog.h> 87 #include <signal.h> 88 #include <errno.h> 89 #include <fcntl.h> 90 #include <dirent.h> 91 #include <stdio.h> 92 #include <stdlib.h> 93 #include <string.h> 94 #include <ctype.h> 95 #include "lp.h" 96 #include "lp.local.h" 97 #include "pathnames.h" 98 #include "extern.h" 99 100 int lflag; /* log requests flag */ 101 int sflag; /* secure (no inet) flag */ 102 int from_remote; /* from remote socket */ 103 104 static void reapchild __P((int)); 105 static void mcleanup __P((int)); 106 static void doit __P((void)); 107 static void startup __P((void)); 108 static void chkhost __P((struct sockaddr_in *)); 109 110 uid_t uid, euid; 111 112 int 113 main(argc, argv) 114 int argc; 115 char **argv; 116 { 117 int f, funix, finet, options, fromlen; 118 fd_set defreadfds; 119 struct sockaddr_un un, fromunix; 120 struct sockaddr_in sin, frominet; 121 int omask, lfd; 122 123 euid = geteuid(); /* these shouldn't be different */ 124 uid = getuid(); 125 options = 0; 126 gethostname(host, sizeof(host)); 127 name = argv[0]; 128 129 while (--argc > 0) { 130 argv++; 131 if (argv[0][0] == '-') 132 switch (argv[0][1]) { 133 case 'd': 134 options |= SO_DEBUG; 135 break; 136 case 'l': 137 lflag++; 138 break; 139 case 's': 140 sflag++; 141 break; 142 } 143 } 144 145 #ifndef DEBUG 146 /* 147 * Set up standard environment by detaching from the parent. 148 */ 149 daemon(0, 0); 150 #endif 151 152 openlog("lpd", LOG_PID, LOG_LPR); 153 syslog(LOG_INFO, "restarted"); 154 (void)umask(0); 155 lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT, 0644); 156 if (lfd < 0) { 157 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 158 exit(1); 159 } 160 if (flock(lfd, LOCK_EX|LOCK_NB) < 0) { 161 if (errno == EWOULDBLOCK) /* active deamon present */ 162 exit(0); 163 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 164 exit(1); 165 } 166 ftruncate(lfd, 0); 167 /* 168 * write process id for others to know 169 */ 170 (void)snprintf(line, sizeof(line), "%u\n", getpid()); 171 f = strlen(line); 172 if (write(lfd, line, f) != f) { 173 syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK); 174 exit(1); 175 } 176 signal(SIGCHLD, reapchild); 177 /* 178 * Restart all the printers. 179 */ 180 startup(); 181 (void)unlink(_PATH_SOCKETNAME); 182 funix = socket(AF_UNIX, SOCK_STREAM, 0); 183 if (funix < 0) { 184 syslog(LOG_ERR, "socket: %m"); 185 exit(1); 186 } 187 #define mask(s) (1 << ((s) - 1)) 188 omask = sigblock(mask(SIGHUP)|mask(SIGINT)|mask(SIGQUIT)|mask(SIGTERM)); 189 signal(SIGHUP, mcleanup); 190 signal(SIGINT, mcleanup); 191 signal(SIGQUIT, mcleanup); 192 signal(SIGTERM, mcleanup); 193 memset(&un, 0, sizeof(un)); 194 un.sun_family = AF_UNIX; 195 strncpy(un.sun_path, _PATH_SOCKETNAME, sizeof(un.sun_path) - 1); 196 #ifndef SUN_LEN 197 #define SUN_LEN(unp) (strlen((unp)->sun_path) + 2) 198 #endif 199 if (bind(funix, (struct sockaddr *)&un, SUN_LEN(&un)) < 0) { 200 syslog(LOG_ERR, "ubind: %m"); 201 exit(1); 202 } 203 sigsetmask(omask); 204 FD_ZERO(&defreadfds); 205 FD_SET(funix, &defreadfds); 206 listen(funix, 5); 207 if (!sflag) 208 finet = socket(AF_INET, SOCK_STREAM, 0); 209 else 210 finet = -1; /* pretend we couldn't open TCP socket. */ 211 if (finet >= 0) { 212 struct servent *sp; 213 214 if (options & SO_DEBUG) 215 if (setsockopt(finet, SOL_SOCKET, SO_DEBUG, 0, 0) < 0) { 216 syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m"); 217 mcleanup(0); 218 } 219 sp = getservbyname("printer", "tcp"); 220 if (sp == NULL) { 221 syslog(LOG_ERR, "printer/tcp: unknown service"); 222 mcleanup(0); 223 } 224 memset(&sin, 0, sizeof(sin)); 225 sin.sin_family = AF_INET; 226 sin.sin_port = sp->s_port; 227 if (bind(finet, (struct sockaddr *)&sin, sizeof(sin)) < 0) { 228 syslog(LOG_ERR, "bind: %m"); 229 mcleanup(0); 230 } 231 FD_SET(finet, &defreadfds); 232 listen(finet, 5); 233 } 234 /* 235 * Main loop: accept, do a request, continue. 236 */ 237 memset(&frominet, 0, sizeof(frominet)); 238 memset(&fromunix, 0, sizeof(fromunix)); 239 for (;;) { 240 int domain, nfds, s; 241 fd_set readfds; 242 243 FD_COPY(&defreadfds, &readfds); 244 nfds = select(20, &readfds, 0, 0, 0); 245 if (nfds <= 0) { 246 if (nfds < 0 && errno != EINTR) 247 syslog(LOG_WARNING, "select: %m"); 248 continue; 249 } 250 if (FD_ISSET(funix, &readfds)) { 251 domain = AF_UNIX, fromlen = sizeof(fromunix); 252 s = accept(funix, 253 (struct sockaddr *)&fromunix, &fromlen); 254 } else /* if (FD_ISSET(finet, &readfds)) */ { 255 domain = AF_INET, fromlen = sizeof(frominet); 256 s = accept(finet, 257 (struct sockaddr *)&frominet, &fromlen); 258 } 259 if (s < 0) { 260 if (errno != EINTR) 261 syslog(LOG_WARNING, "accept: %m"); 262 continue; 263 } 264 if (fork() == 0) { 265 signal(SIGCHLD, SIG_IGN); 266 signal(SIGHUP, SIG_IGN); 267 signal(SIGINT, SIG_IGN); 268 signal(SIGQUIT, SIG_IGN); 269 signal(SIGTERM, SIG_IGN); 270 (void)close(funix); 271 if (!sflag) 272 (void)close(finet); 273 dup2(s, 1); 274 (void)close(s); 275 if (domain == AF_INET) { 276 from_remote = 1; 277 chkhost(&frominet); 278 } else 279 from_remote = 0; 280 doit(); 281 exit(0); 282 } 283 (void)close(s); 284 } 285 } 286 287 static void 288 reapchild(signo) 289 int signo; 290 { 291 union wait status; 292 293 while (wait3((int *)&status, WNOHANG, 0) > 0) 294 ; 295 } 296 297 static void 298 mcleanup(signo) 299 int signo; 300 { 301 if (lflag) 302 syslog(LOG_INFO, "exiting"); 303 unlink(_PATH_SOCKETNAME); 304 exit(0); 305 } 306 307 /* 308 * Stuff for handling job specifications 309 */ 310 char *user[MAXUSERS]; /* users to process */ 311 int users; /* # of users in user array */ 312 int requ[MAXREQUESTS]; /* job number of spool entries */ 313 int requests; /* # of spool requests */ 314 char *person; /* name of person doing lprm */ 315 316 char fromb[MAXHOSTNAMELEN]; /* buffer for client's machine name */ 317 char cbuf[BUFSIZ]; /* command line buffer */ 318 char *cmdnames[] = { 319 "null", 320 "printjob", 321 "recvjob", 322 "displayq short", 323 "displayq long", 324 "rmjob" 325 }; 326 327 static void 328 doit() 329 { 330 register char *cp; 331 register int n; 332 333 for (;;) { 334 cp = cbuf; 335 do { 336 if (cp >= &cbuf[sizeof(cbuf) - 1]) 337 fatal("Command line too long"); 338 if ((n = read(1, cp, 1)) != 1) { 339 if (n < 0) 340 fatal("Lost connection"); 341 return; 342 } 343 } while (*cp++ != '\n'); 344 *--cp = '\0'; 345 cp = cbuf; 346 if (lflag) { 347 if (*cp >= '\1' && *cp <= '\5') 348 syslog(LOG_INFO, "%s requests %s %s", 349 from, cmdnames[*cp], cp+1); 350 else 351 syslog(LOG_INFO, "bad request (%d) from %s", 352 *cp, from); 353 } 354 switch (*cp++) { 355 case '\1': /* check the queue and print any jobs there */ 356 printer = cp; 357 printjob(); 358 break; 359 case '\2': /* receive files to be queued */ 360 if (!from_remote) { 361 syslog(LOG_INFO, "illegal request (%d)", *cp); 362 exit(1); 363 } 364 printer = cp; 365 recvjob(); 366 break; 367 case '\3': /* display the queue (short form) */ 368 case '\4': /* display the queue (long form) */ 369 printer = cp; 370 while (*cp) { 371 if (*cp != ' ') { 372 cp++; 373 continue; 374 } 375 *cp++ = '\0'; 376 while (isspace(*cp)) 377 cp++; 378 if (*cp == '\0') 379 break; 380 if (isdigit(*cp)) { 381 if (requests >= MAXREQUESTS) 382 fatal("Too many requests"); 383 requ[requests++] = atoi(cp); 384 } else { 385 if (users >= MAXUSERS) 386 fatal("Too many users"); 387 user[users++] = cp; 388 } 389 } 390 displayq(cbuf[0] - '\3'); 391 exit(0); 392 case '\5': /* remove a job from the queue */ 393 if (!from_remote) { 394 syslog(LOG_INFO, "illegal request (%d)", *cp); 395 exit(1); 396 } 397 printer = cp; 398 while (*cp && *cp != ' ') 399 cp++; 400 if (!*cp) 401 break; 402 *cp++ = '\0'; 403 person = cp; 404 while (*cp) { 405 if (*cp != ' ') { 406 cp++; 407 continue; 408 } 409 *cp++ = '\0'; 410 while (isspace(*cp)) 411 cp++; 412 if (*cp == '\0') 413 break; 414 if (isdigit(*cp)) { 415 if (requests >= MAXREQUESTS) 416 fatal("Too many requests"); 417 requ[requests++] = atoi(cp); 418 } else { 419 if (users >= MAXUSERS) 420 fatal("Too many users"); 421 user[users++] = cp; 422 } 423 } 424 rmjob(); 425 break; 426 } 427 fatal("Illegal service request"); 428 } 429 } 430 431 /* 432 * Make a pass through the printcap database and start printing any 433 * files left from the last time the machine went down. 434 */ 435 static void 436 startup() 437 { 438 char *buf; 439 register char *cp; 440 int pid; 441 442 /* 443 * Restart the daemons. 444 */ 445 while (cgetnext(&buf, printcapdb) > 0) { 446 for (cp = buf; *cp; cp++) 447 if (*cp == '|' || *cp == ':') { 448 *cp = '\0'; 449 break; 450 } 451 if ((pid = fork()) < 0) { 452 syslog(LOG_WARNING, "startup: cannot fork"); 453 mcleanup(0); 454 } 455 if (!pid) { 456 printer = buf; 457 cgetclose(); 458 printjob(); 459 } 460 } 461 } 462 463 #define DUMMY ":nobody::" 464 465 /* 466 * Check to see if the from host has access to the line printer. 467 */ 468 static void 469 chkhost(f) 470 struct sockaddr_in *f; 471 { 472 register struct hostent *hp; 473 register FILE *hostf; 474 int first = 1; 475 extern char *inet_ntoa(); 476 477 f->sin_port = ntohs(f->sin_port); 478 if (f->sin_family != AF_INET || f->sin_port >= IPPORT_RESERVED) 479 fatal("Malformed from address"); 480 481 /* Need real hostname for temporary filenames */ 482 hp = gethostbyaddr((char *)&f->sin_addr, 483 sizeof(struct in_addr), f->sin_family); 484 if (hp == NULL) 485 fatal("Host name for your address (%s) unknown", 486 inet_ntoa(f->sin_addr)); 487 488 (void)strncpy(fromb, hp->h_name, sizeof(fromb) - 1); 489 from[sizeof(fromb) - 1] = '\0'; 490 from = fromb; 491 492 hostf = fopen(_PATH_HOSTSEQUIV, "r"); 493 again: 494 if (hostf) { 495 if (__ivaliduser(hostf, f->sin_addr.s_addr, 496 DUMMY, DUMMY) == 0) { 497 (void)fclose(hostf); 498 return; 499 } 500 (void)fclose(hostf); 501 } 502 if (first == 1) { 503 first = 0; 504 hostf = fopen(_PATH_HOSTSLPD, "r"); 505 goto again; 506 } 507 fatal("Your host does not have line printer access"); 508 /*NOTREACHED*/ 509 } 510
Indexes created Fri Sep 26 20:09:58 GMT 2025