xref: /freebsd/usr.bin/last/last.c (revision 5b31cc94b10d4bb7109c6b27940a0fc76a44a331)
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 #include <sys/cdefs.h>
40 #include <sys/param.h>
41 #include <sys/capsicum.h>
42 #include <sys/queue.h>
43 #include <sys/stat.h>
44 
45 #include <capsicum_helpers.h>
46 #include <err.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <langinfo.h>
50 #include <locale.h>
51 #include <paths.h>
52 #include <signal.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <time.h>
57 #include <timeconv.h>
58 #include <unistd.h>
59 #include <utmpx.h>
60 
61 #include <libxo/xo.h>
62 
63 #define	NO	0				/* false/no */
64 #define	YES	1				/* true/yes */
65 #define	ATOI2(ar)	((ar)[0] - '0') * 10 + ((ar)[1] - '0'); (ar) += 2;
66 
67 typedef struct arg {
68 	char	*name;				/* argument */
69 #define	REBOOT_TYPE	-1
70 #define	HOST_TYPE	-2
71 #define	TTY_TYPE	-3
72 #define	USER_TYPE	-4
73 	int	type;				/* type of arg */
74 	struct arg	*next;			/* linked list pointer */
75 } ARG;
76 static ARG	*arglist;			/* head of linked list */
77 
78 static SLIST_HEAD(, idtab) idlist;
79 
80 struct idtab {
81 	time_t	logout;				/* log out time */
82 	char	id[sizeof ((struct utmpx *)0)->ut_id]; /* identifier */
83 	SLIST_ENTRY(idtab) list;
84 };
85 
86 static const	char *crmsg;			/* cause of last reboot */
87 static time_t	currentout;			/* current logout value */
88 static long	maxrec;				/* records to display */
89 static const	char *file = NULL;		/* utx.log file */
90 static int	sflag = 0;			/* show delta in seconds */
91 static int	width = 5;			/* show seconds in delta */
92 static int	yflag;				/* show year */
93 static int      d_first;
94 static int	snapfound = 0;			/* found snapshot entry? */
95 static time_t	snaptime;			/* if != 0, we will only
96 						 * report users logged in
97 						 * at this snapshot time
98 						 */
99 
100 static void	 addarg(int, char *);
101 static time_t	 dateconv(char *);
102 static void	 doentry(struct utmpx *);
103 static void	 hostconv(char *);
104 static void	 printentry(struct utmpx *, struct idtab *);
105 static char	*ttyconv(char *);
106 static int	 want(struct utmpx *);
107 static void	 usage(void);
108 static void	 wtmp(void);
109 
110 static void
111 usage(void)
112 {
113 	xo_error(
114 "usage: last [-swy] [-d [[CC]YY][MMDD]hhmm[.SS]] [-f file] [-h host]\n"
115 "            [-n maxrec] [-t tty] [user ...]\n");
116 	exit(1);
117 }
118 
119 int
120 main(int argc, char *argv[])
121 {
122 	int ch;
123 	char *p;
124 
125 	(void) setlocale(LC_TIME, "");
126 	d_first = (*nl_langinfo(D_MD_ORDER) == 'd');
127 
128 	argc = xo_parse_args(argc, argv);
129 	if (argc < 0)
130 		exit(1);
131 	atexit(xo_finish_atexit);
132 
133 	maxrec = -1;
134 	snaptime = 0;
135 	while ((ch = getopt(argc, argv, "0123456789d:f:h:n:st:wy")) != -1)
136 		switch (ch) {
137 		case '0': case '1': case '2': case '3': case '4':
138 		case '5': case '6': case '7': case '8': case '9':
139 			/*
140 			 * kludge: last was originally designed to take
141 			 * a number after a dash.
142 			 */
143 			if (maxrec == -1) {
144 				p = strchr(argv[optind - 1], ch);
145 				if (p == NULL)
146 					p = strchr(argv[optind], ch);
147 				maxrec = atol(p);
148 				if (!maxrec)
149 					exit(0);
150 			}
151 			break;
152 		case 'd':
153 			snaptime = dateconv(optarg);
154 			break;
155 		case 'f':
156 			file = optarg;
157 			break;
158 		case 'h':
159 			hostconv(optarg);
160 			addarg(HOST_TYPE, optarg);
161 			break;
162 		case 'n':
163 			errno = 0;
164 			maxrec = strtol(optarg, &p, 10);
165 			if (p == optarg || *p != '\0' || errno != 0 ||
166 			    maxrec <= 0)
167 				xo_errx(1, "%s: bad line count", optarg);
168 			break;
169 		case 's':
170 			sflag++;	/* Show delta as seconds */
171 			break;
172 		case 't':
173 			addarg(TTY_TYPE, ttyconv(optarg));
174 			break;
175 		case 'w':
176 			width = 8;
177 			break;
178 		case 'y':
179 			yflag++;
180 			break;
181 		case '?':
182 		default:
183 			usage();
184 		}
185 
186 	if (caph_limit_stdio() < 0)
187 		xo_err(1, "can't limit stdio rights");
188 
189 	caph_cache_catpages();
190 	caph_cache_tzdata();
191 
192 	/* Cache UTX database. */
193 	if (setutxdb(UTXDB_LOG, file) != 0)
194 		xo_err(1, "%s", file != NULL ? file : "(default utx db)");
195 
196 	if (caph_enter() < 0)
197 		xo_err(1, "cap_enter");
198 
199 	if (sflag && width == 8) usage();
200 
201 	if (argc) {
202 		setlinebuf(stdout);
203 		for (argv += optind; *argv; ++argv) {
204 			if (strcmp(*argv, "reboot") == 0)
205 				addarg(REBOOT_TYPE, *argv);
206 #define	COMPATIBILITY
207 #ifdef	COMPATIBILITY
208 			/* code to allow "last p5" to work */
209 			addarg(TTY_TYPE, ttyconv(*argv));
210 #endif
211 			addarg(USER_TYPE, *argv);
212 		}
213 	}
214 	wtmp();
215 	exit(0);
216 }
217 
218 /*
219  * wtmp --
220  *	read through the utx.log file
221  */
222 static void
223 wtmp(void)
224 {
225 	struct utmpx *buf = NULL;
226 	struct utmpx *ut;
227 	static unsigned int amount = 0;
228 	time_t t;
229 	char ct[80];
230 	struct tm *tm;
231 
232 	SLIST_INIT(&idlist);
233 	(void)time(&t);
234 
235 	xo_open_container("last-information");
236 
237 	/* Load the last entries from the file. */
238 	while ((ut = getutxent()) != NULL) {
239 		if (amount % 128 == 0) {
240 			buf = realloc(buf, (amount + 128) * sizeof *ut);
241 			if (buf == NULL)
242 				xo_err(1, "realloc");
243 		}
244 		memcpy(&buf[amount++], ut, sizeof *ut);
245 		if (t > ut->ut_tv.tv_sec)
246 			t = ut->ut_tv.tv_sec;
247 	}
248 	endutxent();
249 
250 	/* Display them in reverse order. */
251 	xo_open_list("last");
252 	while (amount > 0)
253 		doentry(&buf[--amount]);
254 	xo_close_list("last");
255 	free(buf);
256 	tm = localtime(&t);
257 	(void) strftime(ct, sizeof(ct), "%+", tm);
258 	xo_emit("\n{:utxdb/%s}", (file == NULL) ? "utx.log" : file);
259 	xo_attr("seconds", "%lu", (unsigned long) t);
260 	xo_emit(" begins {:begins/%hs}\n", ct);
261 	xo_close_container("last-information");
262 }
263 
264 /*
265  * doentry --
266  *	process a single utx.log entry
267  */
268 static void
269 doentry(struct utmpx *bp)
270 {
271 	struct idtab *tt;
272 
273 	/* the machine stopped */
274 	if (bp->ut_type == BOOT_TIME || bp->ut_type == SHUTDOWN_TIME) {
275 		/* everybody just logged out */
276 		while ((tt = SLIST_FIRST(&idlist)) != NULL) {
277 			SLIST_REMOVE_HEAD(&idlist, list);
278 			free(tt);
279 		}
280 		currentout = -bp->ut_tv.tv_sec;
281 		crmsg = bp->ut_type != SHUTDOWN_TIME ?
282 		    "crash" : "shutdown";
283 		/*
284 		 * if we're in snapshot mode, we want to exit if this
285 		 * shutdown/reboot appears while we are tracking the
286 		 * active range
287 		 */
288 		if (snaptime && snapfound)
289 			exit(0);
290 		/*
291 		 * don't print shutdown/reboot entries unless flagged for
292 		 */
293 		if (!snaptime && want(bp))
294 			printentry(bp, NULL);
295 		return;
296 	}
297 	/* date got set */
298 	if (bp->ut_type == OLD_TIME || bp->ut_type == NEW_TIME) {
299 		if (want(bp) && !snaptime)
300 			printentry(bp, NULL);
301 		return;
302 	}
303 
304 	if (bp->ut_type != USER_PROCESS && bp->ut_type != DEAD_PROCESS)
305 		return;
306 
307 	/* find associated identifier */
308 	SLIST_FOREACH(tt, &idlist, list)
309 	    if (!memcmp(tt->id, bp->ut_id, sizeof bp->ut_id))
310 		    break;
311 
312 	if (tt == NULL) {
313 		/* add new one */
314 		tt = malloc(sizeof(struct idtab));
315 		if (tt == NULL)
316 			xo_errx(1, "malloc failure");
317 		tt->logout = currentout;
318 		memcpy(tt->id, bp->ut_id, sizeof bp->ut_id);
319 		SLIST_INSERT_HEAD(&idlist, tt, list);
320 	}
321 
322 	/*
323 	 * print record if not in snapshot mode and wanted
324 	 * or in snapshot mode and in snapshot range
325 	 */
326 	if (bp->ut_type == USER_PROCESS && (want(bp) ||
327 	    (bp->ut_tv.tv_sec < snaptime &&
328 	    (tt->logout > snaptime || tt->logout < 1)))) {
329 		snapfound = 1;
330 		printentry(bp, tt);
331 	}
332 	tt->logout = bp->ut_tv.tv_sec;
333 }
334 
335 /*
336  * printentry --
337  *	output an entry
338  *
339  * If `tt' is non-NULL, use it and `crmsg' to print the logout time or
340  * logout type (crash/shutdown) as appropriate.
341  */
342 static void
343 printentry(struct utmpx *bp, struct idtab *tt)
344 {
345 	char ct[80];
346 	struct tm *tm;
347 	time_t	delta;				/* time difference */
348 	time_t	t;
349 
350 	if (maxrec != -1 && !maxrec--)
351 		exit(0);
352 	xo_open_instance("last");
353 	t = bp->ut_tv.tv_sec;
354 	tm = localtime(&t);
355 	(void) strftime(ct, sizeof(ct), d_first ?
356 	    (yflag ? "%a %e %b %Y %R" : "%a %e %b %R") :
357 	    (yflag ? "%a %b %e %Y %R" : "%a %b %e %R"), tm);
358 	switch (bp->ut_type) {
359 	case BOOT_TIME:
360 		xo_emit("{:user/%-42s/%s}", "boot time");
361 		break;
362 	case SHUTDOWN_TIME:
363 		xo_emit("{:user/%-42s/%s}", "shutdown time");
364 		break;
365 	case OLD_TIME:
366 		xo_emit("{:user/%-42s/%s}", "old time");
367 		break;
368 	case NEW_TIME:
369 		xo_emit("{:user/%-42s/%s}", "new time");
370 		break;
371 	case USER_PROCESS:
372 		xo_emit("{:user/%-10s/%s} {:tty/%-8s/%s} {:from/%-22.22s/%s}",
373 		    bp->ut_user, bp->ut_line, bp->ut_host);
374 		break;
375 	}
376 	xo_attr("seconds", "%lu", (unsigned long)t);
377 	xo_emit(" {:login-time/%hs%c/%s}", ct, tt == NULL ? '\n' : ' ');
378 	if (tt == NULL)
379 		goto end;
380 	if (!tt->logout) {
381 		xo_emit("  {:logout-time/still logged in}\n");
382 		goto end;
383 	}
384 	if (tt->logout < 0) {
385 		tt->logout = -tt->logout;
386 		xo_emit("- {:logout-reason/%s}", crmsg);
387 	} else {
388 		tm = localtime(&tt->logout);
389 		(void) strftime(ct, sizeof(ct), "%R", tm);
390 		xo_attr("seconds", "%lu", (unsigned long)tt->logout);
391 		xo_emit("- {:logout-time/%s}", ct);
392 	}
393 	delta = tt->logout - bp->ut_tv.tv_sec;
394 	xo_attr("seconds", "%ld", (long)delta);
395 	if (sflag) {
396 		xo_emit("  ({:session-length/%8ld})\n", (long)delta);
397 	} else {
398 		tm = gmtime(&delta);
399 		(void) strftime(ct, sizeof(ct), width >= 8 ? "%T" : "%R", tm);
400 		if (delta < 86400)
401 			xo_emit("  ({:session-length/%s})\n", ct);
402 		else
403 			xo_emit(" ({:session-length/%ld+%s})\n",
404 			    (long)delta / 86400, ct);
405 	}
406 
407 end:
408 	xo_close_instance("last");
409 }
410 
411 /*
412  * want --
413  *	see if want this entry
414  */
415 static int
416 want(struct utmpx *bp)
417 {
418 	ARG *step;
419 
420 	if (snaptime)
421 		return (NO);
422 
423 	if (!arglist)
424 		return (YES);
425 
426 	for (step = arglist; step; step = step->next)
427 		switch(step->type) {
428 		case REBOOT_TYPE:
429 			if (bp->ut_type == BOOT_TIME ||
430 			    bp->ut_type == SHUTDOWN_TIME)
431 				return (YES);
432 			break;
433 		case HOST_TYPE:
434 			if (!strcasecmp(step->name, bp->ut_host))
435 				return (YES);
436 			break;
437 		case TTY_TYPE:
438 			if (!strcmp(step->name, bp->ut_line))
439 				return (YES);
440 			break;
441 		case USER_TYPE:
442 			if (!strcmp(step->name, bp->ut_user))
443 				return (YES);
444 			break;
445 		}
446 	return (NO);
447 }
448 
449 /*
450  * addarg --
451  *	add an entry to a linked list of arguments
452  */
453 static void
454 addarg(int type, char *arg)
455 {
456 	ARG *cur;
457 
458 	if ((cur = malloc(sizeof(ARG))) == NULL)
459 		xo_errx(1, "malloc failure");
460 	cur->next = arglist;
461 	cur->type = type;
462 	cur->name = arg;
463 	arglist = cur;
464 }
465 
466 /*
467  * hostconv --
468  *	convert the hostname to search pattern; if the supplied host name
469  *	has a domain attached that is the same as the current domain, rip
470  *	off the domain suffix since that's what login(1) does.
471  */
472 static void
473 hostconv(char *arg)
474 {
475 	static int first = 1;
476 	static char *hostdot, name[MAXHOSTNAMELEN];
477 	char *argdot;
478 
479 	if (!(argdot = strchr(arg, '.')))
480 		return;
481 	if (first) {
482 		first = 0;
483 		if (gethostname(name, sizeof(name)))
484 			xo_err(1, "gethostname");
485 		hostdot = strchr(name, '.');
486 	}
487 	if (hostdot && !strcasecmp(hostdot, argdot))
488 		*argdot = '\0';
489 }
490 
491 /*
492  * ttyconv --
493  *	convert tty to correct name.
494  */
495 static char *
496 ttyconv(char *arg)
497 {
498 	char *mval;
499 
500 	/*
501 	 * kludge -- we assume that all tty's end with
502 	 * a two character suffix.
503 	 */
504 	if (strlen(arg) == 2) {
505 		/* either 6 for "ttyxx" or 8 for "console" */
506 		if ((mval = malloc(8)) == NULL)
507 			xo_errx(1, "malloc failure");
508 		if (!strcmp(arg, "co"))
509 			(void)strcpy(mval, "console");
510 		else {
511 			(void)strcpy(mval, "tty");
512 			(void)strcpy(mval + 3, arg);
513 		}
514 		return (mval);
515 	}
516 	if (!strncmp(arg, _PATH_DEV, sizeof(_PATH_DEV) - 1))
517 		return (arg + 5);
518 	return (arg);
519 }
520 
521 /*
522  * dateconv --
523  * 	Convert the snapshot time in command line given in the format
524  * 	[[CC]YY]MMDDhhmm[.SS]] to a time_t.
525  * 	Derived from atime_arg1() in usr.bin/touch/touch.c
526  */
527 static time_t
528 dateconv(char *arg)
529 {
530         time_t timet;
531         struct tm *t;
532         int yearset;
533         char *p;
534 
535         /* Start with the current time. */
536         if (time(&timet) < 0)
537                 xo_err(1, "time");
538         if ((t = localtime(&timet)) == NULL)
539                 xo_err(1, "localtime");
540 
541         /* [[CC]YY]MMDDhhmm[.SS] */
542         if ((p = strchr(arg, '.')) == NULL)
543                 t->tm_sec = 0; 		/* Seconds defaults to 0. */
544         else {
545                 if (strlen(p + 1) != 2)
546                         goto terr;
547                 *p++ = '\0';
548                 t->tm_sec = ATOI2(p);
549         }
550 
551         yearset = 0;
552         switch (strlen(arg)) {
553         case 12:                	/* CCYYMMDDhhmm */
554                 t->tm_year = ATOI2(arg);
555                 t->tm_year *= 100;
556                 yearset = 1;
557                 /* FALLTHROUGH */
558         case 10:                	/* YYMMDDhhmm */
559                 if (yearset) {
560                         yearset = ATOI2(arg);
561                         t->tm_year += yearset;
562                 } else {
563                         yearset = ATOI2(arg);
564                         if (yearset < 69)
565                                 t->tm_year = yearset + 2000;
566                         else
567                                 t->tm_year = yearset + 1900;
568                 }
569                 t->tm_year -= 1900;     /* Convert to UNIX time. */
570                 /* FALLTHROUGH */
571         case 8:				/* MMDDhhmm */
572                 t->tm_mon = ATOI2(arg);
573                 --t->tm_mon;    	/* Convert from 01-12 to 00-11 */
574                 t->tm_mday = ATOI2(arg);
575                 t->tm_hour = ATOI2(arg);
576                 t->tm_min = ATOI2(arg);
577                 break;
578         case 4:				/* hhmm */
579                 t->tm_hour = ATOI2(arg);
580                 t->tm_min = ATOI2(arg);
581                 break;
582         default:
583                 goto terr;
584         }
585         t->tm_isdst = -1;       	/* Figure out DST. */
586         timet = mktime(t);
587         if (timet == -1)
588 terr:           xo_errx(1,
589         "out of range or illegal time specification: [[CC]YY]MMDDhhmm[.SS]");
590         return timet;
591 }
592