xref: /freebsd/usr.bin/last/last.c (revision 580744621f33383027108364dcadad718df46ffe)
1 /*
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1987, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  * Copyright (c) 2018 Philip Paeps
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
34 static const char copyright[] =
35 "@(#) Copyright (c) 1987, 1993, 1994\n\
36 	The Regents of the University of California.  All rights reserved.\n";
37 #endif /* not lint */
38 
39 #ifndef lint
40 static const char sccsid[] = "@(#)last.c	8.2 (Berkeley) 4/2/94";
41 #endif /* not lint */
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 #include <sys/param.h>
46 #include <sys/capsicum.h>
47 #include <sys/queue.h>
48 #include <sys/stat.h>
49 
50 #include <capsicum_helpers.h>
51 #include <err.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <langinfo.h>
55 #include <locale.h>
56 #include <paths.h>
57 #include <signal.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <time.h>
62 #include <timeconv.h>
63 #include <unistd.h>
64 #include <utmpx.h>
65 
66 #include <libxo/xo.h>
67 
68 #define	NO	0				/* false/no */
69 #define	YES	1				/* true/yes */
70 #define	ATOI2(ar)	((ar)[0] - '0') * 10 + ((ar)[1] - '0'); (ar) += 2;
71 
72 typedef struct arg {
73 	char	*name;				/* argument */
74 #define	REBOOT_TYPE	-1
75 #define	HOST_TYPE	-2
76 #define	TTY_TYPE	-3
77 #define	USER_TYPE	-4
78 	int	type;				/* type of arg */
79 	struct arg	*next;			/* linked list pointer */
80 } ARG;
81 static ARG	*arglist;			/* head of linked list */
82 
83 static SLIST_HEAD(, idtab) idlist;
84 
85 struct idtab {
86 	time_t	logout;				/* log out time */
87 	char	id[sizeof ((struct utmpx *)0)->ut_id]; /* identifier */
88 	SLIST_ENTRY(idtab) list;
89 };
90 
91 static const	char *crmsg;			/* cause of last reboot */
92 static time_t	currentout;			/* current logout value */
93 static long	maxrec;				/* records to display */
94 static const	char *file = NULL;		/* utx.log file */
95 static int	noctfix = 0;			/* locale is C or UTF-8 */
96 static int	sflag = 0;			/* show delta in seconds */
97 static int	width = 5;			/* show seconds in delta */
98 static int	yflag;				/* show year */
99 static int      d_first;
100 static int	snapfound = 0;			/* found snapshot entry? */
101 static time_t	snaptime;			/* if != 0, we will only
102 						 * report users logged in
103 						 * at this snapshot time
104 						 */
105 
106 static void	 addarg(int, char *);
107 static const char *ctf(const char *);
108 static time_t	 dateconv(char *);
109 static void	 doentry(struct utmpx *);
110 static void	 hostconv(char *);
111 static void	 printentry(struct utmpx *, struct idtab *);
112 static char	*ttyconv(char *);
113 static int	 want(struct utmpx *);
114 static void	 usage(void);
115 static void	 wtmp(void);
116 
117 static const char*
118 ctf(const char *fmt) {
119 	static char  buf[31];
120 	const char  *src, *end;
121 	char	    *dst;
122 
123 	if (noctfix)
124 		return (fmt);
125 
126 	end = buf + sizeof(buf);
127 	for (src = fmt, dst = buf; dst < end; *dst++ = *src++) {
128 		if (*src == '\0') {
129 			*dst = '\0';
130 			break;
131 		} else if (*src == '%' && *(src+1) == 's') {
132 			*dst++ = '%';
133 			*dst++ = 'h';
134 			*dst++ = 's';
135 			strlcpy(dst, src+2, end - dst);
136 			return (buf);
137 		}
138 	}
139 	return (buf);
140 }
141 
142 static void
143 usage(void)
144 {
145 	xo_error(
146 "usage: last [-swy] [-d [[CC]YY][MMDD]hhmm[.SS]] [-f file] [-h host]\n"
147 "            [-n maxrec] [-t tty] [user ...]\n");
148 	exit(1);
149 }
150 
151 int
152 main(int argc, char *argv[])
153 {
154 	int ch;
155 	char *p;
156 
157 	(void) setlocale(LC_TIME, "");
158 	d_first = (*nl_langinfo(D_MD_ORDER) == 'd');
159 
160 	(void) setlocale(LC_CTYPE, "");
161 	p = nl_langinfo(CODESET);
162 	if (strcmp(p, "UTF-8") == 0 || strcmp(p, "US-ASCII") == 0)
163 		noctfix = 1;
164 
165 	argc = xo_parse_args(argc, argv);
166 	if (argc < 0)
167 		exit(1);
168 	atexit(xo_finish_atexit);
169 
170 	maxrec = -1;
171 	snaptime = 0;
172 	while ((ch = getopt(argc, argv, "0123456789d:f:h:n:st:wy")) != -1)
173 		switch (ch) {
174 		case '0': case '1': case '2': case '3': case '4':
175 		case '5': case '6': case '7': case '8': case '9':
176 			/*
177 			 * kludge: last was originally designed to take
178 			 * a number after a dash.
179 			 */
180 			if (maxrec == -1) {
181 				p = strchr(argv[optind - 1], ch);
182 				if (p == NULL)
183 					p = strchr(argv[optind], ch);
184 				maxrec = atol(p);
185 				if (!maxrec)
186 					exit(0);
187 			}
188 			break;
189 		case 'd':
190 			snaptime = dateconv(optarg);
191 			break;
192 		case 'f':
193 			file = optarg;
194 			break;
195 		case 'h':
196 			hostconv(optarg);
197 			addarg(HOST_TYPE, optarg);
198 			break;
199 		case 'n':
200 			errno = 0;
201 			maxrec = strtol(optarg, &p, 10);
202 			if (p == optarg || *p != '\0' || errno != 0 ||
203 			    maxrec <= 0)
204 				xo_errx(1, "%s: bad line count", optarg);
205 			break;
206 		case 's':
207 			sflag++;	/* Show delta as seconds */
208 			break;
209 		case 't':
210 			addarg(TTY_TYPE, ttyconv(optarg));
211 			break;
212 		case 'w':
213 			width = 8;
214 			break;
215 		case 'y':
216 			yflag++;
217 			break;
218 		case '?':
219 		default:
220 			usage();
221 		}
222 
223 	if (caph_limit_stdio() < 0)
224 		xo_err(1, "can't limit stdio rights");
225 
226 	caph_cache_catpages();
227 	caph_cache_tzdata();
228 
229 	/* Cache UTX database. */
230 	if (setutxdb(UTXDB_LOG, file) != 0)
231 		xo_err(1, "%s", file != NULL ? file : "(default utx db)");
232 
233 	if (caph_enter() < 0)
234 		xo_err(1, "cap_enter");
235 
236 	if (sflag && width == 8) usage();
237 
238 	if (argc) {
239 		setlinebuf(stdout);
240 		for (argv += optind; *argv; ++argv) {
241 			if (strcmp(*argv, "reboot") == 0)
242 				addarg(REBOOT_TYPE, *argv);
243 #define	COMPATIBILITY
244 #ifdef	COMPATIBILITY
245 			/* code to allow "last p5" to work */
246 			addarg(TTY_TYPE, ttyconv(*argv));
247 #endif
248 			addarg(USER_TYPE, *argv);
249 		}
250 	}
251 	wtmp();
252 	exit(0);
253 }
254 
255 /*
256  * wtmp --
257  *	read through the utx.log file
258  */
259 static void
260 wtmp(void)
261 {
262 	struct utmpx *buf = NULL;
263 	struct utmpx *ut;
264 	static unsigned int amount = 0;
265 	time_t t;
266 	char ct[80];
267 	struct tm *tm;
268 
269 	SLIST_INIT(&idlist);
270 	(void)time(&t);
271 
272 	xo_open_container("last-information");
273 
274 	/* Load the last entries from the file. */
275 	while ((ut = getutxent()) != NULL) {
276 		if (amount % 128 == 0) {
277 			buf = realloc(buf, (amount + 128) * sizeof *ut);
278 			if (buf == NULL)
279 				xo_err(1, "realloc");
280 		}
281 		memcpy(&buf[amount++], ut, sizeof *ut);
282 		if (t > ut->ut_tv.tv_sec)
283 			t = ut->ut_tv.tv_sec;
284 	}
285 	endutxent();
286 
287 	/* Display them in reverse order. */
288 	xo_open_list("last");
289 	while (amount > 0)
290 		doentry(&buf[--amount]);
291 	xo_close_list("last");
292 	free(buf);
293 	tm = localtime(&t);
294 	(void) strftime(ct, sizeof(ct), "%+", tm);
295 	xo_emit("\n{:utxdb/%s}", (file == NULL) ? "utx.log" : file);
296 	xo_attr("seconds", "%lu", (unsigned long) t);
297 	xo_emit(ctf(" begins {:begins/%s}\n"), ct);
298 	xo_close_container("last-information");
299 }
300 
301 /*
302  * doentry --
303  *	process a single utx.log entry
304  */
305 static void
306 doentry(struct utmpx *bp)
307 {
308 	struct idtab *tt;
309 
310 	/* the machine stopped */
311 	if (bp->ut_type == BOOT_TIME || bp->ut_type == SHUTDOWN_TIME) {
312 		/* everybody just logged out */
313 		while ((tt = SLIST_FIRST(&idlist)) != NULL) {
314 			SLIST_REMOVE_HEAD(&idlist, list);
315 			free(tt);
316 		}
317 		currentout = -bp->ut_tv.tv_sec;
318 		crmsg = bp->ut_type != SHUTDOWN_TIME ?
319 		    "crash" : "shutdown";
320 		/*
321 		 * if we're in snapshot mode, we want to exit if this
322 		 * shutdown/reboot appears while we we are tracking the
323 		 * active range
324 		 */
325 		if (snaptime && snapfound)
326 			exit(0);
327 		/*
328 		 * don't print shutdown/reboot entries unless flagged for
329 		 */
330 		if (!snaptime && want(bp))
331 			printentry(bp, NULL);
332 		return;
333 	}
334 	/* date got set */
335 	if (bp->ut_type == OLD_TIME || bp->ut_type == NEW_TIME) {
336 		if (want(bp) && !snaptime)
337 			printentry(bp, NULL);
338 		return;
339 	}
340 
341 	if (bp->ut_type != USER_PROCESS && bp->ut_type != DEAD_PROCESS)
342 		return;
343 
344 	/* find associated identifier */
345 	SLIST_FOREACH(tt, &idlist, list)
346 	    if (!memcmp(tt->id, bp->ut_id, sizeof bp->ut_id))
347 		    break;
348 
349 	if (tt == NULL) {
350 		/* add new one */
351 		tt = malloc(sizeof(struct idtab));
352 		if (tt == NULL)
353 			xo_errx(1, "malloc failure");
354 		tt->logout = currentout;
355 		memcpy(tt->id, bp->ut_id, sizeof bp->ut_id);
356 		SLIST_INSERT_HEAD(&idlist, tt, list);
357 	}
358 
359 	/*
360 	 * print record if not in snapshot mode and wanted
361 	 * or in snapshot mode and in snapshot range
362 	 */
363 	if (bp->ut_type == USER_PROCESS && (want(bp) ||
364 	    (bp->ut_tv.tv_sec < snaptime &&
365 	    (tt->logout > snaptime || tt->logout < 1)))) {
366 		snapfound = 1;
367 		printentry(bp, tt);
368 	}
369 	tt->logout = bp->ut_tv.tv_sec;
370 }
371 
372 /*
373  * printentry --
374  *	output an entry
375  *
376  * If `tt' is non-NULL, use it and `crmsg' to print the logout time or
377  * logout type (crash/shutdown) as appropriate.
378  */
379 static void
380 printentry(struct utmpx *bp, struct idtab *tt)
381 {
382 	char ct[80];
383 	struct tm *tm;
384 	time_t	delta;				/* time difference */
385 	time_t	t;
386 
387 	if (maxrec != -1 && !maxrec--)
388 		exit(0);
389 	xo_open_instance("last");
390 	t = bp->ut_tv.tv_sec;
391 	tm = localtime(&t);
392 	(void) strftime(ct, sizeof(ct), d_first ?
393 	    (yflag ? "%a %e %b %Y %R" : "%a %e %b %R") :
394 	    (yflag ? "%a %b %e %Y %R" : "%a %b %e %R"), tm);
395 	switch (bp->ut_type) {
396 	case BOOT_TIME:
397 		xo_emit("{:user/%-42s/%s}", "boot time");
398 		break;
399 	case SHUTDOWN_TIME:
400 		xo_emit("{:user/%-42s/%s}", "shutdown time");
401 		break;
402 	case OLD_TIME:
403 		xo_emit("{:user/%-42s/%s}", "old time");
404 		break;
405 	case NEW_TIME:
406 		xo_emit("{:user/%-42s/%s}", "new time");
407 		break;
408 	case USER_PROCESS:
409 		xo_emit("{:user/%-10s/%s} {:tty/%-8s/%s} {:from/%-22.22s/%s}",
410 		    bp->ut_user, bp->ut_line, bp->ut_host);
411 		break;
412 	}
413 	xo_attr("seconds", "%lu", (unsigned long)t);
414 	xo_emit(ctf(" {:login-time/%s%c/%s}"), ct, tt == NULL ? '\n' : ' ');
415 	if (tt == NULL)
416 		goto end;
417 	if (!tt->logout) {
418 		xo_emit("  {:logout-time/still logged in}\n");
419 		goto end;
420 	}
421 	if (tt->logout < 0) {
422 		tt->logout = -tt->logout;
423 		xo_emit("- {:logout-reason/%s}", crmsg);
424 	} else {
425 		tm = localtime(&tt->logout);
426 		(void) strftime(ct, sizeof(ct), "%R", tm);
427 		xo_attr("seconds", "%lu", (unsigned long)tt->logout);
428 		xo_emit(ctf("- {:logout-time/%s}"), ct);
429 	}
430 	delta = tt->logout - bp->ut_tv.tv_sec;
431 	xo_attr("seconds", "%ld", (long)delta);
432 	if (sflag) {
433 		xo_emit("  ({:session-length/%8ld})\n", (long)delta);
434 	} else {
435 		tm = gmtime(&delta);
436 		(void) strftime(ct, sizeof(ct), width >= 8 ? "%T" : "%R", tm);
437 		if (delta < 86400)
438 			xo_emit(ctf("  ({:session-length/%s})\n"), ct);
439 		else
440 			xo_emit(ctf(" ({:session-length/%ld+%s})\n"),
441 			    (long)delta / 86400, ct);
442 	}
443 
444 end:
445 	xo_close_instance("last");
446 }
447 
448 /*
449  * want --
450  *	see if want this entry
451  */
452 static int
453 want(struct utmpx *bp)
454 {
455 	ARG *step;
456 
457 	if (snaptime)
458 		return (NO);
459 
460 	if (!arglist)
461 		return (YES);
462 
463 	for (step = arglist; step; step = step->next)
464 		switch(step->type) {
465 		case REBOOT_TYPE:
466 			if (bp->ut_type == BOOT_TIME ||
467 			    bp->ut_type == SHUTDOWN_TIME)
468 				return (YES);
469 			break;
470 		case HOST_TYPE:
471 			if (!strcasecmp(step->name, bp->ut_host))
472 				return (YES);
473 			break;
474 		case TTY_TYPE:
475 			if (!strcmp(step->name, bp->ut_line))
476 				return (YES);
477 			break;
478 		case USER_TYPE:
479 			if (!strcmp(step->name, bp->ut_user))
480 				return (YES);
481 			break;
482 		}
483 	return (NO);
484 }
485 
486 /*
487  * addarg --
488  *	add an entry to a linked list of arguments
489  */
490 static void
491 addarg(int type, char *arg)
492 {
493 	ARG *cur;
494 
495 	if ((cur = malloc(sizeof(ARG))) == NULL)
496 		xo_errx(1, "malloc failure");
497 	cur->next = arglist;
498 	cur->type = type;
499 	cur->name = arg;
500 	arglist = cur;
501 }
502 
503 /*
504  * hostconv --
505  *	convert the hostname to search pattern; if the supplied host name
506  *	has a domain attached that is the same as the current domain, rip
507  *	off the domain suffix since that's what login(1) does.
508  */
509 static void
510 hostconv(char *arg)
511 {
512 	static int first = 1;
513 	static char *hostdot, name[MAXHOSTNAMELEN];
514 	char *argdot;
515 
516 	if (!(argdot = strchr(arg, '.')))
517 		return;
518 	if (first) {
519 		first = 0;
520 		if (gethostname(name, sizeof(name)))
521 			xo_err(1, "gethostname");
522 		hostdot = strchr(name, '.');
523 	}
524 	if (hostdot && !strcasecmp(hostdot, argdot))
525 		*argdot = '\0';
526 }
527 
528 /*
529  * ttyconv --
530  *	convert tty to correct name.
531  */
532 static char *
533 ttyconv(char *arg)
534 {
535 	char *mval;
536 
537 	/*
538 	 * kludge -- we assume that all tty's end with
539 	 * a two character suffix.
540 	 */
541 	if (strlen(arg) == 2) {
542 		/* either 6 for "ttyxx" or 8 for "console" */
543 		if ((mval = malloc(8)) == NULL)
544 			xo_errx(1, "malloc failure");
545 		if (!strcmp(arg, "co"))
546 			(void)strcpy(mval, "console");
547 		else {
548 			(void)strcpy(mval, "tty");
549 			(void)strcpy(mval + 3, arg);
550 		}
551 		return (mval);
552 	}
553 	if (!strncmp(arg, _PATH_DEV, sizeof(_PATH_DEV) - 1))
554 		return (arg + 5);
555 	return (arg);
556 }
557 
558 /*
559  * dateconv --
560  * 	Convert the snapshot time in command line given in the format
561  * 	[[CC]YY]MMDDhhmm[.SS]] to a time_t.
562  * 	Derived from atime_arg1() in usr.bin/touch/touch.c
563  */
564 static time_t
565 dateconv(char *arg)
566 {
567         time_t timet;
568         struct tm *t;
569         int yearset;
570         char *p;
571 
572         /* Start with the current time. */
573         if (time(&timet) < 0)
574                 xo_err(1, "time");
575         if ((t = localtime(&timet)) == NULL)
576                 xo_err(1, "localtime");
577 
578         /* [[CC]YY]MMDDhhmm[.SS] */
579         if ((p = strchr(arg, '.')) == NULL)
580                 t->tm_sec = 0; 		/* Seconds defaults to 0. */
581         else {
582                 if (strlen(p + 1) != 2)
583                         goto terr;
584                 *p++ = '\0';
585                 t->tm_sec = ATOI2(p);
586         }
587 
588         yearset = 0;
589         switch (strlen(arg)) {
590         case 12:                	/* CCYYMMDDhhmm */
591                 t->tm_year = ATOI2(arg);
592                 t->tm_year *= 100;
593                 yearset = 1;
594                 /* FALLTHROUGH */
595         case 10:                	/* YYMMDDhhmm */
596                 if (yearset) {
597                         yearset = ATOI2(arg);
598                         t->tm_year += yearset;
599                 } else {
600                         yearset = ATOI2(arg);
601                         if (yearset < 69)
602                                 t->tm_year = yearset + 2000;
603                         else
604                                 t->tm_year = yearset + 1900;
605                 }
606                 t->tm_year -= 1900;     /* Convert to UNIX time. */
607                 /* FALLTHROUGH */
608         case 8:				/* MMDDhhmm */
609                 t->tm_mon = ATOI2(arg);
610                 --t->tm_mon;    	/* Convert from 01-12 to 00-11 */
611                 t->tm_mday = ATOI2(arg);
612                 t->tm_hour = ATOI2(arg);
613                 t->tm_min = ATOI2(arg);
614                 break;
615         case 4:				/* hhmm */
616                 t->tm_hour = ATOI2(arg);
617                 t->tm_min = ATOI2(arg);
618                 break;
619         default:
620                 goto terr;
621         }
622         t->tm_isdst = -1;       	/* Figure out DST. */
623         timet = mktime(t);
624         if (timet == -1)
625 terr:           xo_errx(1,
626         "out of range or illegal time specification: [[CC]YY]MMDDhhmm[.SS]");
627         return timet;
628 }
629