xref: /netbsd-src/usr.bin/w/w.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
1 /*	$NetBSD: w.c,v 1.90 2020/08/01 17:53:38 kim Exp $	*/
2 
3 /*-
4  * Copyright (c) 1980, 1991, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __COPYRIGHT("@(#) Copyright (c) 1980, 1991, 1993, 1994\
35  The Regents of the University of California.  All rights reserved.");
36 #endif /* not lint */
37 
38 #ifndef lint
39 #if 0
40 static char sccsid[] = "@(#)w.c	8.6 (Berkeley) 6/30/94";
41 #else
42 __RCSID("$NetBSD: w.c,v 1.90 2020/08/01 17:53:38 kim Exp $");
43 #endif
44 #endif /* not lint */
45 
46 /*
47  * w - print system status (who and what)
48  *
49  * This program is similar to the systat command on Tenex/Tops 10/20
50  *
51  */
52 #include <sys/param.h>
53 #include <sys/types.h>
54 #include <sys/time.h>
55 #include <sys/stat.h>
56 #include <sys/sysctl.h>
57 #include <sys/proc.h>
58 #include <sys/ioctl.h>
59 #include <sys/socket.h>
60 
61 #include <netinet/in.h>
62 #include <arpa/inet.h>
63 
64 #include <ctype.h>
65 #include <err.h>
66 #include <errno.h>
67 #include <fcntl.h>
68 #include <kvm.h>
69 #include <limits.h>
70 #include <netdb.h>
71 #include <nlist.h>
72 #include <paths.h>
73 #include <stdio.h>
74 #include <stdlib.h>
75 #include <string.h>
76 #include <time.h>
77 #include <tzfile.h>
78 #include <unistd.h>
79 #ifdef SUPPORT_UTMP
80 #include <utmp.h>
81 #endif
82 #ifdef SUPPORT_UTMPX
83 #include <utmpx.h>
84 #endif
85 #include <vis.h>
86 
87 #include "extern.h"
88 
89 struct timespec	boottime;
90 struct winsize	ws;
91 kvm_t	       *kd;
92 time_t		now;		/* the current time of day */
93 int		ttywidth;	/* width of tty */
94 int		argwidth;	/* width of tty left to print process args */
95 int		header = 1;	/* true if -h flag: don't print heading */
96 int		nflag;		/* true if -n flag: don't convert addrs */
97 int		wflag;		/* true if -w flag: wide printout */
98 int		sortidle;	/* sort bu idle time */
99 char	       *sel_user;	/* login of particular user selected */
100 char		domain[MAXHOSTNAMELEN + 1];
101 int maxname = 8, maxline = 3, maxhost = 16;
102 
103 /*
104  * One of these per active utmp entry.
105  */
106 struct	entry {
107 	struct	entry *next;
108 	char name[UTX_USERSIZE + 1];
109 	char line[UTX_LINESIZE + 1];
110 	char host[UTX_HOSTSIZE + 1];
111 	char type[2];
112 	struct timeval tv;
113 	dev_t	tdev;			/* dev_t of terminal */
114 	time_t	idle;			/* idle time of terminal in seconds */
115 	struct	kinfo_proc2 *tp;	/* `most interesting' tty proc */
116 	struct	kinfo_proc2 *pp;	/* pid proc */
117 	pid_t	pid;			/* pid or ~0 if not known */
118 } *ehead = NULL, **nextp = &ehead;
119 
120 static void	pr_args(struct kinfo_proc2 *);
121 static void	pr_header(time_t *, int);
122 static int	proc_compare_wrapper(const struct kinfo_proc2 *,
123     const struct kinfo_proc2 *);
124 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
125 static int	ttystat(const char *, struct stat *);
126 static void	process(struct entry *);
127 #endif
128 static void	fixhost(struct entry *ep);
129 __dead static void	usage(int);
130 
131 int
132 main(int argc, char **argv)
133 {
134 	struct kinfo_proc2 *kp;
135 	struct entry *ep;
136 	int ch, i, nentries, nusers, wcmd, curtain, use_sysctl;
137 	char *memf, *nlistf, *usrnp;
138 	const char *options;
139 	time_t then;
140 	size_t len;
141 #ifdef SUPPORT_UTMP
142 	struct utmp *ut;
143 #endif
144 #ifdef SUPPORT_UTMPX
145 	struct utmpx *utx;
146 #endif
147 	const char *progname;
148 	char errbuf[_POSIX2_LINE_MAX];
149 
150 	setprogname(argv[0]);
151 
152 	/* Are we w(1) or uptime(1)? */
153 	progname = getprogname();
154 	if (*progname == '-')
155 		progname++;
156 	if (*progname == 'u') {
157 		wcmd = 0;
158 		options = "";
159 	} else {
160 		wcmd = 1;
161 		options = "hiM:N:nw";
162 	}
163 
164 	memf = nlistf = NULL;
165 	while ((ch = getopt(argc, argv, options)) != -1)
166 		switch (ch) {
167 		case 'h':
168 			header = 0;
169 			break;
170 		case 'i':
171 			sortidle = 1;
172 			break;
173 		case 'M':
174 			header = 0;
175 			memf = optarg;
176 			break;
177 		case 'N':
178 			nlistf = optarg;
179 			break;
180 		case 'n':
181 			nflag = 1;
182 			break;
183 		case 'w':
184 			wflag = 1;
185 			break;
186 		case '?':
187 		default:
188 			usage(wcmd);
189 		}
190 	argc -= optind;
191 	argv += optind;
192 
193 	use_sysctl = (memf == NULL && nlistf == NULL);
194 
195 	if ((kd = kvm_openfiles(nlistf, memf, NULL,
196 	    memf == NULL ? KVM_NO_FILES : O_RDONLY, errbuf)) == NULL)
197 		errx(1, "%s", errbuf);
198 
199 	(void)time(&now);
200 
201 	if (use_sysctl) {
202 		len = sizeof(curtain);
203 		if (sysctlbyname("security.curtain", &curtain, &len,
204 		    NULL, 0) == -1)
205 			curtain = 0;
206 	}
207 
208 	if (!nflag) {
209 		int	rv;
210 		char	*p;
211 
212 		rv = gethostname(domain, sizeof(domain));
213 		domain[sizeof(domain) - 1] = '\0';
214 		if (rv < 0 || (p = strchr(domain, '.')) == 0)
215 			domain[0] = '\0';
216 		else
217 			memmove(domain, p, strlen(p) + 1);
218 	}
219 
220 #ifdef SUPPORT_UTMPX
221 	setutxent();
222 #endif
223 #ifdef SUPPORT_UTMP
224 	setutent();
225 #endif
226 
227 	if (*argv)
228 		sel_user = *argv;
229 
230 	nusers = 0;
231 #ifdef SUPPORT_UTMPX
232 	while ((utx = getutxent()) != NULL) {
233 		if (utx->ut_type != USER_PROCESS)
234 			continue;
235 		++nusers;
236 
237 #ifndef SUPPORT_UTMP
238 		if (wcmd == 0)
239 			continue;
240 #endif	/* !SUPPORT_UTMP */
241 
242 		if (sel_user &&
243 		    strncmp(utx->ut_name, sel_user, sizeof(utx->ut_name)) != 0)
244 			continue;
245 		if ((ep = calloc(1, sizeof(struct entry))) == NULL)
246 			err(1, NULL);
247 		(void)memcpy(ep->line, utx->ut_line, sizeof(utx->ut_line));
248 		ep->line[sizeof(utx->ut_line)] = '\0';
249 		*nextp = ep;
250 		nextp = &(ep->next);
251 
252 		if (wcmd == 0)
253 			continue;
254 
255 		(void)memcpy(ep->name, utx->ut_name, sizeof(utx->ut_name));
256 		ep->name[sizeof(utx->ut_name)] = '\0';
257 		if (!nflag || getnameinfo((struct sockaddr *)&utx->ut_ss,
258 		    utx->ut_ss.ss_len, ep->host, sizeof(ep->host), NULL, 0,
259 		    NI_NUMERICHOST) != 0) {
260 			(void)memcpy(ep->host, utx->ut_host,
261 			    sizeof(utx->ut_host));
262 			ep->host[sizeof(utx->ut_host)] = '\0';
263 		}
264 		fixhost(ep);
265 		ep->type[0] = 'x';
266 		ep->tv = utx->ut_tv;
267 		ep->pid = utx->ut_pid;
268 		process(ep);
269 	}
270 #endif
271 
272 #ifdef SUPPORT_UTMP
273 	while ((ut = getutent()) != NULL) {
274 		if (ut->ut_name[0] == '\0')
275 			continue;
276 
277 		if (sel_user &&
278 		    strncmp(ut->ut_name, sel_user, sizeof(ut->ut_name)) != 0)
279 			continue;
280 
281 		/* Don't process entries that we have utmpx for */
282 		for (ep = ehead; ep != NULL; ep = ep->next) {
283 			if (strncmp(ep->line, ut->ut_line,
284 			    sizeof(ut->ut_line)) == 0)
285 				break;
286 		}
287 		if (ep != NULL)
288 			continue;
289 
290 		++nusers;
291 
292 		if (wcmd == 0)
293 			continue;
294 
295 		if ((ep = calloc(1, sizeof(struct entry))) == NULL)
296 			err(1, NULL);
297 		(void)memcpy(ep->name, ut->ut_name, sizeof(ut->ut_name));
298 		(void)memcpy(ep->line, ut->ut_line, sizeof(ut->ut_line));
299 		(void)memcpy(ep->host, ut->ut_host, sizeof(ut->ut_host));
300 		ep->name[sizeof(ut->ut_name)] = '\0';
301 		ep->line[sizeof(ut->ut_line)] = '\0';
302 		ep->host[sizeof(ut->ut_host)] = '\0';
303 		fixhost(ep);
304 		ep->tv.tv_sec = ut->ut_time;
305 		*nextp = ep;
306 		nextp = &(ep->next);
307 		process(ep);
308 	}
309 #endif
310 
311 #ifdef SUPPORT_UTMPX
312 	endutxent();
313 #endif
314 #ifdef SUPPORT_UTMP
315 	endutent();
316 #endif
317 
318 	if (header || wcmd == 0) {
319 		pr_header(&now, nusers);
320 		if (wcmd == 0)
321 			exit (0);
322 	}
323 
324 	if ((kp = kvm_getproc2(kd, KERN_PROC_ALL, 0,
325 	    sizeof(struct kinfo_proc2), &nentries)) == NULL)
326 		errx(1, "%s", kvm_geterr(kd));
327 
328 	/* Include trailing space because TTY header starts one column early. */
329 	for (i = 0; i < nentries; i++, kp++) {
330 
331 		for (ep = ehead; ep != NULL; ep = ep->next) {
332 			if (ep->tdev != 0 && ep->tdev == kp->p_tdev &&
333 			    kp->p__pgid == kp->p_tpgid) {
334 				/*
335 				 * Proc is in foreground of this
336 				 * terminal
337 				 */
338 				if (proc_compare_wrapper(ep->tp, kp))
339 					ep->tp = kp;
340 				break;
341 			}
342 			if (ep->pid != 0 && ep->pid == kp->p_pid) {
343 				ep->pp = kp;
344 				break;
345 			}
346 		}
347 	}
348 
349 	if ((ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 &&
350 	    ioctl(STDERR_FILENO, TIOCGWINSZ, &ws) == -1 &&
351 	    ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == -1) || ws.ws_col == 0)
352 		ttywidth = 79;
353 	else
354 		ttywidth = ws.ws_col - 1;
355 
356 	if (!wflag && maxhost > (ttywidth / 3))
357 		maxhost = ttywidth / 3;
358 
359 	argwidth = printf("%-*s TTY     %-*s %*s  IDLE WHAT\n",
360 	    maxname, "USER", maxhost, "FROM",
361 	    7 /* "dddhhXm" */, "LOGIN@");
362 	argwidth -= sizeof("WHAT\n") - 1 /* NUL */;
363 	argwidth = ttywidth - argwidth;
364 	if (argwidth < 4)
365 		argwidth = 8;
366 	if (wflag)
367 		argwidth = -1;
368 
369 	/* sort by idle time */
370 	if (sortidle && ehead != NULL) {
371 		struct entry *from = ehead, *save;
372 
373 		ehead = NULL;
374 		while (from != NULL) {
375 			for (nextp = &ehead;
376 			    (*nextp) && from->idle >= (*nextp)->idle;
377 			    nextp = &(*nextp)->next)
378 				continue;
379 			save = from;
380 			from = from->next;
381 			save->next = *nextp;
382 			*nextp = save;
383 		}
384 	}
385 #if defined(SUPPORT_UTMP) && defined(SUPPORT_UTMPX)
386 	else if (ehead != NULL) {
387 		struct entry *from = ehead, *save;
388 
389 		ehead = NULL;
390 		while (from != NULL) {
391 			for (nextp = &ehead;
392 			    (*nextp) && strcmp(from->line, (*nextp)->line) > 0;
393 			    nextp = &(*nextp)->next)
394 				continue;
395 			save = from;
396 			from = from->next;
397 			save->next = *nextp;
398 			*nextp = save;
399 		}
400 	}
401 #endif
402 
403 	for (ep = ehead; ep != NULL; ep = ep->next) {
404 		if (ep->tp != NULL)
405 			kp = ep->tp;
406 		else if (ep->pp != NULL)
407 			kp = ep->pp;
408 		else if (ep->pid != 0) {
409 			if (curtain)
410 				kp = NULL;
411 			else {
412 				warnx("Stale utmp%s entry: %s %s %s",
413 				    ep->type, ep->name, ep->line, ep->host);
414 				continue;
415 			}
416 		}
417 		usrnp = (kp == NULL) ? ep->name : kp->p_login;
418 		(void)printf("%-*s %-7.7s %-*.*s ",
419 		    maxname, usrnp, ep->line,
420 		    maxhost, maxhost, ep->host);
421 		then = (time_t)ep->tv.tv_sec;
422 		pr_attime(&then, &now);
423 		pr_idle(ep->idle);
424 		pr_args(kp);
425 		(void)printf("\n");
426 	}
427 	exit(0);
428 }
429 
430 static void
431 pr_args(struct kinfo_proc2 *kp)
432 {
433 	char **argv;
434 	int left;
435 
436 	if (kp == 0)
437 		goto nothing;
438 	left = argwidth;
439 	argv = kvm_getargv2(kd, kp, (argwidth < 0) ? 0 : argwidth);
440 	if (argv == 0) {
441 		fmt_putc('(', &left);
442 		fmt_puts((char *)kp->p_comm, &left);
443 		fmt_putc(')', &left);
444 		return;
445 	}
446 	while (*argv) {
447 		fmt_puts(*argv, &left);
448 		argv++;
449 		fmt_putc(' ', &left);
450 	}
451 	return;
452 nothing:
453 	putchar('-');
454 }
455 
456 static void
457 pr_header(time_t *nowp, int nusers)
458 {
459 	double avenrun[3];
460 	time_t uptime;
461 	int days, hrs, mins;
462 	int mib[2];
463 	size_t size, i;
464 	char buf[256];
465 
466 	/*
467 	 * Print time of day.
468 	 *
469 	 * SCCS forces the string manipulation below, as it replaces
470 	 * %, M, and % in a character string with the file name.
471 	 */
472 	(void)strftime(buf, sizeof(buf), "%l:%" "M%p", localtime(nowp));
473 	buf[sizeof(buf) - 1] = '\0';
474 	(void)printf("%s ", buf);
475 
476 	/*
477 	 * Print how long system has been up.
478 	 * (Found by looking getting "boottime" from the kernel)
479 	 */
480 	mib[0] = CTL_KERN;
481 	mib[1] = KERN_BOOTTIME;
482 	size = sizeof(boottime);
483 	if (sysctl(mib, 2, &boottime, &size, NULL, 0) != -1 &&
484 	    boottime.tv_sec != 0) {
485 		uptime = now - boottime.tv_sec;
486 		uptime += 30;
487 		if (uptime > SECSPERMIN) {
488 			days = uptime / SECSPERDAY;
489 			uptime %= SECSPERDAY;
490 			hrs = uptime / SECSPERHOUR;
491 			uptime %= SECSPERHOUR;
492 			mins = uptime / SECSPERMIN;
493 			(void)printf(" up");
494 			if (days > 0)
495 				(void)printf(" %d day%s,", days,
496 				    days > 1 ? "s" : "");
497 			if (hrs > 0 && mins > 0)
498 				(void)printf(" %2d:%02d,", hrs, mins);
499 			else {
500 				if (hrs > 0)
501 					(void)printf(" %d hr%s,",
502 					    hrs, hrs > 1 ? "s" : "");
503 				if (mins > 0)
504 					(void)printf(" %d min%s,",
505 					    mins, mins > 1 ? "s" : "");
506 			}
507 		}
508 	}
509 
510 	/* Print number of users logged in to system */
511 	(void)printf(" %d user%s", nusers, nusers != 1 ? "s" : "");
512 
513 	/*
514 	 * Print 1, 5, and 15 minute load averages.
515 	 */
516 	if (getloadavg(avenrun, sizeof(avenrun) / sizeof(avenrun[0])) == -1)
517 		(void)printf(", no load average information available\n");
518 	else {
519 		(void)printf(", load averages:");
520 		for (i = 0; i < (sizeof(avenrun) / sizeof(avenrun[0])); i++) {
521 			if (i > 0)
522 				(void)printf(",");
523 			(void)printf(" %.2f", avenrun[i]);
524 		}
525 		(void)printf("\n");
526 	}
527 }
528 
529 #if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
530 static int
531 ttystat(const char *line, struct stat *st)
532 {
533 	char ttybuf[MAXPATHLEN];
534 
535 	(void)snprintf(ttybuf, sizeof(ttybuf), "%s%s", _PATH_DEV, line);
536 	return stat(ttybuf, st);
537 }
538 
539 static void
540 process(struct entry *ep)
541 {
542 	struct stat st;
543 	time_t touched;
544 	int max;
545 
546 	if ((max = strlen(ep->name)) > maxname)
547 		maxname = max;
548 	if ((max = strlen(ep->line)) > maxline)
549 		maxline = max;
550 	if ((max = strlen(ep->host)) > maxhost)
551 		maxhost = max;
552 
553 	ep->tdev = 0;
554 	ep->idle = (time_t)-1;
555 
556 #ifdef SUPPORT_UTMP
557 	/*
558 	 * Hack to recognize and correctly parse
559 	 * ut entry made by ftpd. The "tty" used
560 	 * by ftpd is not a real tty, just identifier in
561 	 * form ftpPID. Pid parsed from the "tty name"
562 	 * is used later to match corresponding process.
563 	 * NB: This is only used for utmp entries. For utmpx,
564 	 * we already have the pid.
565 	 */
566 	if (ep->pid == 0 && strncmp(ep->line, "ftp", 3) == 0) {
567 		ep->pid = strtol(ep->line + 3, NULL, 10);
568 		return;
569 	}
570 #endif
571 	if (ttystat(ep->line, &st) == -1)
572 		return;
573 
574 	ep->tdev = st.st_rdev;
575 	/*
576 	 * If this is the console device, attempt to ascertain
577 	 * the true console device dev_t.
578 	 */
579 	if (ep->tdev == 0) {
580 		int mib[2];
581 		size_t size;
582 
583 		mib[0] = CTL_KERN;
584 		mib[1] = KERN_CONSDEV;
585 		size = sizeof(dev_t);
586 		(void) sysctl(mib, 2, &ep->tdev, &size, NULL, 0);
587 	}
588 
589 	touched = st.st_atime;
590 	if (touched < ep->tv.tv_sec) {
591 		/* tty untouched since before login */
592 		touched = ep->tv.tv_sec;
593 	}
594 	if ((ep->idle = now - touched) < 0)
595 		ep->idle = 0;
596 }
597 #endif
598 
599 static int
600 proc_compare_wrapper(const struct kinfo_proc2 *p1,
601     const struct kinfo_proc2 *p2)
602 {
603 	struct kinfo_lwp *l1, *l2;
604 	int cnt;
605 
606 	if (p1 == NULL)
607 		return 1;
608 
609 	l1 = kvm_getlwps(kd, p1->p_pid, 0, sizeof(*l1), &cnt);
610 	if (l1 == NULL || cnt == 0)
611 		return 1;
612 
613 	l2 = kvm_getlwps(kd, p2->p_pid, 0, sizeof(*l1), &cnt);
614 	if (l2 == NULL || cnt == 0)
615 		return 0;
616 
617 	return proc_compare(p1, l1, p2, l2);
618 }
619 
620 static void
621 fixhost(struct entry *ep)
622 {
623 	char host_buf[sizeof(ep->host)];
624 	char *b, *m, *p, *r, *x;
625 	struct hostent *hp;
626 	union {
627 		struct in_addr l4;
628 		struct in6_addr l6;
629 	} l;
630 
631 	strlcpy(host_buf, *ep->host ? ep->host : "-", sizeof(host_buf));
632 	p = host_buf;
633 
634 	/*
635 	 * One ':' in hostname means X display number, more is IPv6.
636 	 */
637 	for (x = p; x < &host_buf[sizeof(host_buf)]; x++)
638 		if (*x == '\0' || *x == ':')
639 			break;
640 	if (x == p + sizeof(host_buf) || *x != ':')
641 		m = x = NULL;
642 	else {
643 		for (m = x + 1; m < &host_buf[sizeof(host_buf)]; m++)
644 			if (*m == '\0' || *m == ':')
645 				break;
646 		if (m == p + sizeof(host_buf) || *m != ':') {
647 			*x++ = '\0';
648 			m = NULL;
649 		} else
650 			x = NULL;
651 	}
652 
653 	/*
654 	 * Leading '[' indicates an IP address inside brackets.
655 	 */
656 	b = NULL;
657 	if (!nflag && (*p == '[')) {
658 		for (b = p++; b < &host_buf[sizeof(host_buf)]; b++)
659 			if (*b == '\0' || *b == ']')
660 				break;
661 		if (b < &host_buf[sizeof(host_buf)] && *b == ']') {
662 			*b = '\0';
663 			for (x = b + 1; x < &host_buf[sizeof(host_buf)]; x++)
664 				if (*x == '\0' || *x == ':')
665 					break;
666 			if (x < &host_buf[sizeof(host_buf)] && *x == ':')
667 				*x++ = '\0';
668 		} else
669 			b = NULL;
670 	}
671 
672 	int af = m ? AF_INET6 : AF_INET;
673 	size_t alen = m ? sizeof(l.l6) : sizeof(l.l4);
674 	if (!nflag && inet_pton(af, p, &l) &&
675 	    (hp = gethostbyaddr((char *)&l, alen, af)))
676 		r = hp->h_name;
677 	else {
678 		if (b)
679 			*b = ']';
680 		r = host_buf;
681 	}
682 
683 	if (domain[0] != '\0') {
684 		p = r;
685 		p += strlen(r);
686 		p -= strlen(domain);
687 		if (p > r &&
688 		    strcasecmp(p, domain) == 0)
689 			*p = '\0';
690 	}
691 
692 	if (x)
693 		(void)snprintf(ep->host, sizeof(ep->host), "%s:%s", r, x);
694 	else
695 		strlcpy(ep->host, r, sizeof(ep->host));
696 }
697 
698 static void
699 usage(int wcmd)
700 {
701 
702 	if (wcmd)
703 		(void)fprintf(stderr,
704 		    "Usage: %s [-hinw] [-M core] [-N system] [user]\n",
705 		    getprogname());
706 	else
707 		(void)fprintf(stderr, "Usage: %s\n", getprogname());
708 	exit(1);
709 }
710