1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
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. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#ifndef lint
34static const char copyright[] =
35"@(#) Copyright (c) 1983, 1993, 1994\n\
36	The Regents of the University of California.  All rights reserved.\n";
37#endif /* not lint */
38
39#if 0
40#ifndef lint
41static char sccsid[] = "@(#)lpd.c	8.7 (Berkeley) 5/10/95";
42#endif /* not lint */
43#endif
44
45#include "lp.cdefs.h"		/* A cross-platform version of <sys/cdefs.h> */
46__FBSDID("$FreeBSD$");
47
48/*
49 * lpd -- line printer daemon.
50 *
51 * Listen for a connection and perform the requested operation.
52 * Operations are:
53 *	\1printer\n
54 *		check the queue for jobs and print any found.
55 *	\2printer\n
56 *		receive a job from another machine and queue it.
57 *	\3printer [users ...] [jobs ...]\n
58 *		return the current state of the queue (short form).
59 *	\4printer [users ...] [jobs ...]\n
60 *		return the current state of the queue (long form).
61 *	\5printer person [users ...] [jobs ...]\n
62 *		remove jobs from the queue.
63 *
64 * Strategy to maintain protected spooling area:
65 *	1. Spooling area is writable only by daemon and spooling group
66 *	2. lpr runs setuid root and setgrp spooling group; it uses
67 *	   root to access any file it wants (verifying things before
68 *	   with an access call) and group id to know how it should
69 *	   set up ownership of files in the spooling area.
70 *	3. Files in spooling area are owned by root, group spooling
71 *	   group, with mode 660.
72 *	4. lpd, lpq and lprm run setuid daemon and setgrp spooling group to
73 *	   access files and printer.  Users can't get to anything
74 *	   w/o help of lpq and lprm programs.
75 */
76
77#include <sys/param.h>
78#include <sys/wait.h>
79#include <sys/types.h>
80#include <sys/socket.h>
81#include <sys/un.h>
82#include <sys/stat.h>
83#include <sys/file.h>
84#include <netinet/in.h>
85#include <arpa/inet.h>
86
87#include <netdb.h>
88#include <unistd.h>
89#include <syslog.h>
90#include <signal.h>
91#include <err.h>
92#include <errno.h>
93#include <fcntl.h>
94#include <dirent.h>
95#include <stdio.h>
96#include <stdlib.h>
97#include <string.h>
98#include <sysexits.h>
99#include <ctype.h>
100#include "lp.h"
101#include "lp.local.h"
102#include "pathnames.h"
103#include "extern.h"
104
105int	lflag;				/* log requests flag */
106int	sflag;				/* no incoming port flag */
107int	from_remote;			/* from remote socket */
108
109int		 main(int argc, char **_argv);
110static void	 reapchild(int _signo);
111static void	 mcleanup(int _signo);
112static void	 doit(void);
113static void	 startup(void);
114static void	 chkhost(struct sockaddr *_f, int _ch_opts);
115static int	 ckqueue(struct printer *_pp);
116static void	 fhosterr(int _ch_opts, char *_sysmsg, char *_usermsg);
117static int	*socksetup(int _af, int _debuglvl);
118static void	 usage(void);
119
120/* XXX from libc/net/rcmd.c */
121extern int __ivaliduser_sa(FILE *, struct sockaddr *, socklen_t,
122				const char *, const char *);
123
124uid_t	uid, euid;
125
126#define LPD_NOPORTCHK	0001		/* skip reserved-port check */
127#define LPD_LOGCONNERR	0002		/* (sys)log connection errors */
128#define LPD_ADDFROMLINE	0004		/* just used for fhosterr() */
129
130int
131main(int argc, char **argv)
132{
133	int ch_options, errs, f, funix, *finet, i, lfd, socket_debug;
134	fd_set defreadfds;
135	struct sockaddr_un un, fromunix;
136	struct sockaddr_storage frominet;
137	socklen_t fromlen;
138	sigset_t omask, nmask;
139	struct servent *sp, serv;
140	int inet_flag = 0, inet6_flag = 0;
141
142	euid = geteuid();	/* these shouldn't be different */
143	uid = getuid();
144
145	ch_options = 0;
146	socket_debug = 0;
147	gethostname(local_host, sizeof(local_host));
148
149	progname = "lpd";
150
151	if (euid != 0)
152		errx(EX_NOPERM,"must run as root");
153
154	errs = 0;
155	while ((i = getopt(argc, argv, "cdlpswW46")) != -1)
156		switch (i) {
157		case 'c':
158			/* log all kinds of connection-errors to syslog */
159			ch_options |= LPD_LOGCONNERR;
160			break;
161		case 'd':
162			socket_debug++;
163			break;
164		case 'l':
165			lflag++;
166			break;
167		case 'p':		/* letter initially used for -s */
168			/*
169			 * This will probably be removed with 5.0-release.
170			 */
171			/* FALLTHROUGH */
172		case 's':		/* secure (no inet) */
173			sflag++;
174			break;
175		case 'w':		/* netbsd uses -w for maxwait */
176			/*
177			 * This will be removed after the release of 4.4, as
178			 * it conflicts with -w in netbsd's lpd.  For now it
179			 * is just a warning, so we won't suddenly break lpd
180			 * for anyone who is currently using the option.
181			 */
182			syslog(LOG_WARNING,
183			    "NOTE: the -w option has been renamed -W");
184			syslog(LOG_WARNING,
185			    "NOTE: please change your lpd config to use -W");
186			/* FALLTHROUGH */
187		case 'W':
188			/* allow connections coming from a non-reserved port */
189			/* (done by some lpr-implementations for MS-Windows) */
190			ch_options |= LPD_NOPORTCHK;
191			break;
192		case '4':
193			family = PF_INET;
194			inet_flag++;
195			break;
196		case '6':
197#ifdef INET6
198			family = PF_INET6;
199			inet6_flag++;
200#else
201			errx(EX_USAGE, "lpd compiled sans INET6 (IPv6 support)");
202#endif
203			break;
204		/*
205		 * The following options are not in FreeBSD (yet?), but are
206		 * listed here to "reserve" them, because the option-letters
207		 * are used by either NetBSD or OpenBSD (as of July 2001).
208		 */
209		case 'b':		/* set bind-addr */
210		case 'n':		/* set max num of children */
211		case 'r':		/* allow 'of' for remote ptrs */
212					/* ...[not needed in freebsd] */
213			/* FALLTHROUGH */
214		default:
215			errs++;
216		}
217	if (inet_flag && inet6_flag)
218		family = PF_UNSPEC;
219	argc -= optind;
220	argv += optind;
221	if (errs)
222		usage();
223
224	if (argc == 1) {
225		if ((i = atoi(argv[0])) == 0)
226			usage();
227		if (i < 0 || i > USHRT_MAX)
228			errx(EX_USAGE, "port # %d is invalid", i);
229
230		serv.s_port = htons(i);
231		sp = &serv;
232		argc--;
233	} else {
234		sp = getservbyname("printer", "tcp");
235		if (sp == NULL)
236			errx(EX_OSFILE, "printer/tcp: unknown service");
237	}
238
239	if (argc != 0)
240		usage();
241
242	/*
243	 * We run chkprintcap right away to catch any errors and blat them
244	 * to stderr while we still have it open, rather than sending them
245	 * to syslog and leaving the user wondering why lpd started and
246	 * then stopped.  There should probably be a command-line flag to
247	 * ignore errors from chkprintcap.
248	 */
249	{
250		pid_t pid;
251		int status;
252		pid = fork();
253		if (pid < 0) {
254			err(EX_OSERR, "cannot fork");
255		} else if (pid == 0) {	/* child */
256			execl(_PATH_CHKPRINTCAP, _PATH_CHKPRINTCAP, (char *)0);
257			err(EX_OSERR, "cannot execute %s", _PATH_CHKPRINTCAP);
258		}
259		if (waitpid(pid, &status, 0) < 0) {
260			err(EX_OSERR, "cannot wait");
261		}
262		if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
263			errx(EX_OSFILE, "%d errors in printcap file, exiting",
264			     WEXITSTATUS(status));
265	}
266
267#ifndef DEBUG
268	/*
269	 * Set up standard environment by detaching from the parent.
270	 */
271	daemon(0, 0);
272#endif
273
274	openlog("lpd", LOG_PID, LOG_LPR);
275	syslog(LOG_INFO, "lpd startup: logging=%d%s%s", lflag,
276	    socket_debug ? " dbg" : "", sflag ? " net-secure" : "");
277	(void) umask(0);
278	/*
279	 * NB: This depends on O_NONBLOCK semantics doing the right thing;
280	 * i.e., applying only to the O_EXLOCK and not to the rest of the
281	 * open/creation.  As of 1997-12-02, this is the case for commonly-
282	 * used filesystems.  There are other places in this code which
283	 * make the same assumption.
284	 */
285	lfd = open(_PATH_MASTERLOCK, O_WRONLY|O_CREAT|O_EXLOCK|O_NONBLOCK,
286		   LOCK_FILE_MODE);
287	if (lfd < 0) {
288		if (errno == EWOULDBLOCK)	/* active daemon present */
289			exit(0);
290		syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
291		exit(1);
292	}
293	fcntl(lfd, F_SETFL, 0);	/* turn off non-blocking mode */
294	ftruncate(lfd, 0);
295	/*
296	 * write process id for others to know
297	 */
298	sprintf(line, "%u\n", getpid());
299	f = strlen(line);
300	if (write(lfd, line, f) != f) {
301		syslog(LOG_ERR, "%s: %m", _PATH_MASTERLOCK);
302		exit(1);
303	}
304	signal(SIGCHLD, reapchild);
305	/*
306	 * Restart all the printers.
307	 */
308	startup();
309	(void) unlink(_PATH_SOCKETNAME);
310	funix = socket(AF_UNIX, SOCK_STREAM, 0);
311	if (funix < 0) {
312		syslog(LOG_ERR, "socket: %m");
313		exit(1);
314	}
315
316	sigemptyset(&nmask);
317	sigaddset(&nmask, SIGHUP);
318	sigaddset(&nmask, SIGINT);
319	sigaddset(&nmask, SIGQUIT);
320	sigaddset(&nmask, SIGTERM);
321	sigprocmask(SIG_BLOCK, &nmask, &omask);
322
323	(void) umask(07);
324	signal(SIGHUP, mcleanup);
325	signal(SIGINT, mcleanup);
326	signal(SIGQUIT, mcleanup);
327	signal(SIGTERM, mcleanup);
328	memset(&un, 0, sizeof(un));
329	un.sun_family = AF_UNIX;
330	strcpy(un.sun_path, _PATH_SOCKETNAME);
331#ifndef SUN_LEN
332#define SUN_LEN(unp) (strlen((unp)->sun_path) + 2)
333#endif
334	if (bind(funix, (struct sockaddr *)&un, SUN_LEN(&un)) < 0) {
335		syslog(LOG_ERR, "ubind: %m");
336		exit(1);
337	}
338	(void) umask(0);
339	sigprocmask(SIG_SETMASK, &omask, (sigset_t *)0);
340	FD_ZERO(&defreadfds);
341	FD_SET(funix, &defreadfds);
342	listen(funix, 5);
343	if (sflag == 0) {
344		finet = socksetup(family, socket_debug);
345	} else
346		finet = NULL;	/* pretend we couldn't open TCP socket. */
347	if (finet) {
348		for (i = 1; i <= *finet; i++) {
349			FD_SET(finet[i], &defreadfds);
350			listen(finet[i], 5);
351		}
352	}
353	/*
354	 * Main loop: accept, do a request, continue.
355	 */
356	memset(&frominet, 0, sizeof(frominet));
357	memset(&fromunix, 0, sizeof(fromunix));
358	if (lflag)
359		syslog(LOG_INFO, "lpd startup: ready to accept requests");
360	/*
361	 * XXX - should be redone for multi-protocol
362	 */
363	for (;;) {
364		int domain, nfds, s;
365		fd_set readfds;
366
367		FD_COPY(&defreadfds, &readfds);
368		nfds = select(20, &readfds, 0, 0, 0);
369		if (nfds <= 0) {
370			if (nfds < 0 && errno != EINTR)
371				syslog(LOG_WARNING, "select: %m");
372			continue;
373		}
374		domain = -1;		    /* avoid compile-time warning */
375		s = -1;			    /* avoid compile-time warning */
376		if (FD_ISSET(funix, &readfds)) {
377			domain = AF_UNIX, fromlen = sizeof(fromunix);
378			s = accept(funix,
379			    (struct sockaddr *)&fromunix, &fromlen);
380 		} else {
381                        for (i = 1; i <= *finet; i++)
382				if (FD_ISSET(finet[i], &readfds)) {
383					domain = AF_INET;
384					fromlen = sizeof(frominet);
385					s = accept(finet[i],
386					    (struct sockaddr *)&frominet,
387					    &fromlen);
388				}
389		}
390		if (s < 0) {
391			if (errno != EINTR)
392				syslog(LOG_WARNING, "accept: %m");
393			continue;
394		}
395		if (fork() == 0) {
396			/*
397			 * Note that printjob() also plays around with
398			 * signal-handling routines, and may need to be
399			 * changed when making changes to signal-handling.
400			 */
401			signal(SIGCHLD, SIG_DFL);
402			signal(SIGHUP, SIG_IGN);
403			signal(SIGINT, SIG_IGN);
404			signal(SIGQUIT, SIG_IGN);
405			signal(SIGTERM, SIG_IGN);
406			(void) close(funix);
407			if (sflag == 0 && finet) {
408                        	for (i = 1; i <= *finet; i++)
409					(void)close(finet[i]);
410			}
411			dup2(s, STDOUT_FILENO);
412			(void) close(s);
413			if (domain == AF_INET) {
414				/* for both AF_INET and AF_INET6 */
415				from_remote = 1;
416 				chkhost((struct sockaddr *)&frominet,
417				    ch_options);
418			} else
419				from_remote = 0;
420			doit();
421			exit(0);
422		}
423		(void) close(s);
424	}
425}
426
427static void
428reapchild(int signo __unused)
429{
430	int status;
431
432	while (wait3(&status, WNOHANG, 0) > 0)
433		;
434}
435
436static void
437mcleanup(int signo)
438{
439	/*
440	 * XXX syslog(3) is not signal-safe.
441	 */
442	if (lflag) {
443		if (signo)
444			syslog(LOG_INFO, "exiting on signal %d", signo);
445		else
446			syslog(LOG_INFO, "exiting");
447	}
448	unlink(_PATH_SOCKETNAME);
449	exit(0);
450}
451
452/*
453 * Stuff for handling job specifications
454 */
455char	*user[MAXUSERS];	/* users to process */
456int	users;			/* # of users in user array */
457int	requ[MAXREQUESTS];	/* job number of spool entries */
458int	requests;		/* # of spool requests */
459char	*person;		/* name of person doing lprm */
460
461		 /* buffer to hold the client's machine-name */
462static char	 frombuf[MAXHOSTNAMELEN];
463char	cbuf[BUFSIZ];		/* command line buffer */
464const char	*cmdnames[] = {
465	"null",
466	"printjob",
467	"recvjob",
468	"displayq short",
469	"displayq long",
470	"rmjob"
471};
472
473static void
474doit(void)
475{
476	char *cp, *printer;
477	int n;
478	int status;
479	struct printer myprinter, *pp = &myprinter;
480
481	init_printer(&myprinter);
482
483	for (;;) {
484		cp = cbuf;
485		do {
486			if (cp >= &cbuf[sizeof(cbuf) - 1])
487				fatal(0, "Command line too long");
488			if ((n = read(STDOUT_FILENO, cp, 1)) != 1) {
489				if (n < 0)
490					fatal(0, "Lost connection");
491				return;
492			}
493		} while (*cp++ != '\n');
494		*--cp = '\0';
495		cp = cbuf;
496		if (lflag) {
497			if (*cp >= '\1' && *cp <= '\5')
498				syslog(LOG_INFO, "%s requests %s %s",
499					from_host, cmdnames[(u_char)*cp], cp+1);
500			else
501				syslog(LOG_INFO, "bad request (%d) from %s",
502					*cp, from_host);
503		}
504		switch (*cp++) {
505		case CMD_CHECK_QUE: /* check the queue, print any jobs there */
506			startprinting(cp);
507			break;
508		case CMD_TAKE_THIS: /* receive files to be queued */
509			if (!from_remote) {
510				syslog(LOG_INFO, "illegal request (%d)", *cp);
511				exit(1);
512			}
513			recvjob(cp);
514			break;
515		case CMD_SHOWQ_SHORT: /* display the queue (short form) */
516		case CMD_SHOWQ_LONG: /* display the queue (long form) */
517			/* XXX - this all needs to be redone. */
518			printer = cp;
519			while (*cp) {
520				if (*cp != ' ') {
521					cp++;
522					continue;
523				}
524				*cp++ = '\0';
525				while (isspace(*cp))
526					cp++;
527				if (*cp == '\0')
528					break;
529				if (isdigit(*cp)) {
530					if (requests >= MAXREQUESTS)
531						fatal(0, "Too many requests");
532					requ[requests++] = atoi(cp);
533				} else {
534					if (users >= MAXUSERS)
535						fatal(0, "Too many users");
536					user[users++] = cp;
537				}
538			}
539			status = getprintcap(printer, pp);
540			if (status < 0)
541				fatal(pp, "%s", pcaperr(status));
542			displayq(pp, cbuf[0] == CMD_SHOWQ_LONG);
543			exit(0);
544		case CMD_RMJOB:	/* remove a job from the queue */
545			if (!from_remote) {
546				syslog(LOG_INFO, "illegal request (%d)", *cp);
547				exit(1);
548			}
549			printer = cp;
550			while (*cp && *cp != ' ')
551				cp++;
552			if (!*cp)
553				break;
554			*cp++ = '\0';
555			person = cp;
556			while (*cp) {
557				if (*cp != ' ') {
558					cp++;
559					continue;
560				}
561				*cp++ = '\0';
562				while (isspace(*cp))
563					cp++;
564				if (*cp == '\0')
565					break;
566				if (isdigit(*cp)) {
567					if (requests >= MAXREQUESTS)
568						fatal(0, "Too many requests");
569					requ[requests++] = atoi(cp);
570				} else {
571					if (users >= MAXUSERS)
572						fatal(0, "Too many users");
573					user[users++] = cp;
574				}
575			}
576			rmjob(printer);
577			break;
578		}
579		fatal(0, "Illegal service request");
580	}
581}
582
583/*
584 * Make a pass through the printcap database and start printing any
585 * files left from the last time the machine went down.
586 */
587static void
588startup(void)
589{
590	int pid, status, more;
591	struct printer myprinter, *pp = &myprinter;
592
593	more = firstprinter(pp, &status);
594	if (status)
595		goto errloop;
596	while (more) {
597		if (ckqueue(pp) <= 0) {
598			goto next;
599		}
600		if (lflag)
601			syslog(LOG_INFO, "lpd startup: work for %s",
602			    pp->printer);
603		if ((pid = fork()) < 0) {
604			syslog(LOG_WARNING, "lpd startup: cannot fork for %s",
605			    pp->printer);
606			mcleanup(0);
607		}
608		if (pid == 0) {
609			lastprinter();
610			printjob(pp);
611			/* NOTREACHED */
612		}
613		do {
614next:
615			more = nextprinter(pp, &status);
616errloop:
617			if (status)
618				syslog(LOG_WARNING,
619				    "lpd startup: printcap entry for %s has errors, skipping",
620				    pp->printer ? pp->printer : "<noname?>");
621		} while (more && status);
622	}
623}
624
625/*
626 * Make sure there's some work to do before forking off a child
627 */
628static int
629ckqueue(struct printer *pp)
630{
631	register struct dirent *d;
632	DIR *dirp;
633	char *spooldir;
634
635	spooldir = pp->spool_dir;
636	if ((dirp = opendir(spooldir)) == NULL)
637		return (-1);
638	while ((d = readdir(dirp)) != NULL) {
639		if (d->d_name[0] != 'c' || d->d_name[1] != 'f')
640			continue;	/* daemon control files only */
641		closedir(dirp);
642		return (1);		/* found something */
643	}
644	closedir(dirp);
645	return (0);
646}
647
648#define DUMMY ":nobody::"
649
650/*
651 * Check to see if the host connecting to this host has access to any
652 * lpd services on this host.
653 */
654static void
655chkhost(struct sockaddr *f, int ch_opts)
656{
657	struct addrinfo hints, *res, *r;
658	register FILE *hostf;
659	char hostbuf[NI_MAXHOST], ip[NI_MAXHOST];
660	char serv[NI_MAXSERV];
661	char *syserr, *usererr;
662	int error, errsav, fpass, good;
663
664	from_host = ".na.";
665
666	/* Need real hostname for temporary filenames */
667	error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0,
668	    NI_NAMEREQD);
669	if (error) {
670		errsav = error;
671		error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf),
672		    NULL, 0, NI_NUMERICHOST);
673		if (error) {
674			asprintf(&syserr,
675			    "can not determine hostname for remote host (%d,%d)",
676			    errsav, error);
677			asprintf(&usererr,
678			    "Host name for your address is not known");
679			fhosterr(ch_opts, syserr, usererr);
680			/* NOTREACHED */
681		}
682		asprintf(&syserr,
683		    "Host name for remote host (%s) not known (%d)",
684		    hostbuf, errsav);
685		asprintf(&usererr,
686		    "Host name for your address (%s) is not known",
687		    hostbuf);
688		fhosterr(ch_opts, syserr, usererr);
689		/* NOTREACHED */
690	}
691
692	strlcpy(frombuf, hostbuf, sizeof(frombuf));
693	from_host = frombuf;
694	ch_opts |= LPD_ADDFROMLINE;
695
696	/* Need address in stringform for comparison (no DNS lookup here) */
697	error = getnameinfo(f, f->sa_len, hostbuf, sizeof(hostbuf), NULL, 0,
698	    NI_NUMERICHOST);
699	if (error) {
700		asprintf(&syserr, "Cannot print IP address (error %d)",
701		    error);
702		asprintf(&usererr, "Cannot print IP address for your host");
703		fhosterr(ch_opts, syserr, usererr);
704		/* NOTREACHED */
705	}
706	from_ip = strdup(hostbuf);
707
708	/* Reject numeric addresses */
709	memset(&hints, 0, sizeof(hints));
710	hints.ai_family = family;
711	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
712	hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST;
713	if (getaddrinfo(from_host, NULL, &hints, &res) == 0) {
714		freeaddrinfo(res);
715		/* This syslog message already includes from_host */
716		ch_opts &= ~LPD_ADDFROMLINE;
717		asprintf(&syserr, "reverse lookup results in non-FQDN %s",
718		    from_host);
719		/* same message to both syslog and remote user */
720		fhosterr(ch_opts, syserr, syserr);
721		/* NOTREACHED */
722	}
723
724	/* Check for spoof, ala rlogind */
725	memset(&hints, 0, sizeof(hints));
726	hints.ai_family = family;
727	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
728	error = getaddrinfo(from_host, NULL, &hints, &res);
729	if (error) {
730		asprintf(&syserr, "dns lookup for address %s failed: %s",
731		    from_ip, gai_strerror(error));
732		asprintf(&usererr, "hostname for your address (%s) unknown: %s",
733		    from_ip, gai_strerror(error));
734		fhosterr(ch_opts, syserr, usererr);
735		/* NOTREACHED */
736	}
737	good = 0;
738	for (r = res; good == 0 && r; r = r->ai_next) {
739		error = getnameinfo(r->ai_addr, r->ai_addrlen, ip, sizeof(ip),
740		    NULL, 0, NI_NUMERICHOST);
741		if (!error && !strcmp(from_ip, ip))
742			good = 1;
743	}
744	if (res)
745		freeaddrinfo(res);
746	if (good == 0) {
747		asprintf(&syserr, "address for remote host (%s) not matched",
748		    from_ip);
749		asprintf(&usererr,
750		    "address for your hostname (%s) not matched", from_ip);
751		fhosterr(ch_opts, syserr, usererr);
752		/* NOTREACHED */
753	}
754
755	fpass = 1;
756	hostf = fopen(_PATH_HOSTSEQUIV, "r");
757again:
758	if (hostf) {
759		if (__ivaliduser_sa(hostf, f, f->sa_len, DUMMY, DUMMY) == 0) {
760			(void) fclose(hostf);
761			goto foundhost;
762		}
763		(void) fclose(hostf);
764	}
765	if (fpass == 1) {
766		fpass = 2;
767		hostf = fopen(_PATH_HOSTSLPD, "r");
768		goto again;
769	}
770	/* This syslog message already includes from_host */
771	ch_opts &= ~LPD_ADDFROMLINE;
772	asprintf(&syserr, "refused connection from %s, sip=%s", from_host,
773	    from_ip);
774	asprintf(&usererr,
775	    "Print-services are not available to your host (%s).", from_host);
776	fhosterr(ch_opts, syserr, usererr);
777	/* NOTREACHED */
778
779foundhost:
780	if (ch_opts & LPD_NOPORTCHK)
781		return;			/* skip the reserved-port check */
782
783	error = getnameinfo(f, f->sa_len, NULL, 0, serv, sizeof(serv),
784	    NI_NUMERICSERV);
785	if (error) {
786		/* same message to both syslog and remote user */
787		asprintf(&syserr, "malformed from-address (%d)", error);
788		fhosterr(ch_opts, syserr, syserr);
789		/* NOTREACHED */
790	}
791
792	if (atoi(serv) >= IPPORT_RESERVED) {
793		/* same message to both syslog and remote user */
794		asprintf(&syserr, "connected from invalid port (%s)", serv);
795		fhosterr(ch_opts, syserr, syserr);
796		/* NOTREACHED */
797	}
798}
799
800/*
801 * Handle fatal errors in chkhost.  The first message will optionally be
802 * sent to syslog, the second one is sent to the connecting host.
803 *
804 * The idea is that the syslog message is meant for an administrator of a
805 * print server (the host receiving connections), while the usermsg is meant
806 * for a remote user who may or may not be clueful, and may or may not be
807 * doing something nefarious.  Some remote users (eg, MS-Windows...) may not
808 * even see whatever message is sent, which is why there's the option to
809 * start 'lpd' with the connection-errors also sent to syslog.
810 *
811 * Given that hostnames can theoretically be fairly long (well, over 250
812 * bytes), it would probably be helpful to have the 'from_host' field at
813 * the end of any error messages which include that info.
814 *
815 * These are Fatal host-connection errors, so this routine does not return.
816 */
817static void
818fhosterr(int ch_opts, char *sysmsg, char *usermsg)
819{
820
821	/*
822	 * If lpd was started up to print connection errors, then write
823	 * the syslog message before the user message.
824	 * And for many of the syslog messages, it is helpful to first
825	 * write the from_host (if it is known) as a separate syslog
826	 * message, since the hostname may be so long.
827	 */
828	if (ch_opts & LPD_LOGCONNERR) {
829		if (ch_opts & LPD_ADDFROMLINE) {
830		    syslog(LOG_WARNING, "for connection from %s:", from_host);
831		}
832		syslog(LOG_WARNING, "%s", sysmsg);
833	}
834
835	/*
836	 * Now send the error message to the remote host which is trying
837	 * to make the connection.
838	 */
839	printf("%s [@%s]: %s\n", progname, local_host, usermsg);
840	fflush(stdout);
841
842	/*
843	 * Add a minimal delay before exiting (and disconnecting from the
844	 * sending-host).  This is just in case that machine responds by
845	 * INSTANTLY retrying (and instantly re-failing...).  This may also
846	 * give the other side more time to read the error message.
847	 */
848	sleep(2);			/* a paranoid throttling measure */
849	exit(1);
850}
851
852/* setup server socket for specified address family */
853/* if af is PF_UNSPEC more than one socket may be returned */
854/* the returned list is dynamically allocated, so caller needs to free it */
855static int *
856socksetup(int af, int debuglvl)
857{
858	struct addrinfo hints, *res, *r;
859	int error, maxs, *s, *socks;
860	const int on = 1;
861
862	memset(&hints, 0, sizeof(hints));
863	hints.ai_flags = AI_PASSIVE;
864	hints.ai_family = af;
865	hints.ai_socktype = SOCK_STREAM;
866	error = getaddrinfo(NULL, "printer", &hints, &res);
867	if (error) {
868		syslog(LOG_ERR, "%s", gai_strerror(error));
869		mcleanup(0);
870	}
871
872	/* Count max number of sockets we may open */
873	for (maxs = 0, r = res; r; r = r->ai_next, maxs++)
874		;
875	socks = malloc((maxs + 1) * sizeof(int));
876	if (!socks) {
877		syslog(LOG_ERR, "couldn't allocate memory for sockets");
878		mcleanup(0);
879	}
880
881	*socks = 0;   /* num of sockets counter at start of array */
882	s = socks + 1;
883	for (r = res; r; r = r->ai_next) {
884		*s = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
885		if (*s < 0) {
886			syslog(LOG_DEBUG, "socket(): %m");
887			continue;
888		}
889		if (setsockopt(*s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on))
890		    < 0) {
891			syslog(LOG_ERR, "setsockopt(SO_REUSEADDR): %m");
892			close(*s);
893			continue;
894		}
895		if (debuglvl)
896			if (setsockopt(*s, SOL_SOCKET, SO_DEBUG, &debuglvl,
897			    sizeof(debuglvl)) < 0) {
898				syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m");
899				close(*s);
900				continue;
901			}
902		if (r->ai_family == AF_INET6) {
903			if (setsockopt(*s, IPPROTO_IPV6, IPV6_V6ONLY,
904				       &on, sizeof(on)) < 0) {
905				syslog(LOG_ERR,
906				       "setsockopt (IPV6_V6ONLY): %m");
907				close(*s);
908				continue;
909			}
910		}
911		if (bind(*s, r->ai_addr, r->ai_addrlen) < 0) {
912			syslog(LOG_DEBUG, "bind(): %m");
913			close(*s);
914			continue;
915		}
916		(*socks)++;
917		s++;
918	}
919
920	if (res)
921		freeaddrinfo(res);
922
923	if (*socks == 0) {
924		syslog(LOG_ERR, "Couldn't bind to any socket");
925		free(socks);
926		mcleanup(0);
927	}
928	return(socks);
929}
930
931static void
932usage(void)
933{
934#ifdef INET6
935	fprintf(stderr, "usage: lpd [-cdlsW46] [port#]\n");
936#else
937	fprintf(stderr, "usage: lpd [-cdlsW] [port#]\n");
938#endif
939	exit(EX_USAGE);
940}
941