xref: /freebsd/usr.bin/last/last.c (revision 4543ef516683042d46f3bd3bb8a4f3f746e00499)
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 #include <sys/param.h>
34 #include <sys/capsicum.h>
35 #include <sys/queue.h>
36 #include <sys/stat.h>
37 
38 #include <capsicum_helpers.h>
39 #include <err.h>
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <langinfo.h>
43 #include <locale.h>
44 #include <paths.h>
45 #include <signal.h>
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <string.h>
49 #include <time.h>
50 #include <timeconv.h>
51 #include <unistd.h>
52 #include <utmpx.h>
53 
54 #include <libxo/xo.h>
55 
56 #define	NO	0				/* false/no */
57 #define	YES	1				/* true/yes */
58 #define	ATOI2(ar)	((ar)[0] - '0') * 10 + ((ar)[1] - '0'); (ar) += 2;
59 
60 typedef struct arg {
61 	char	*name;				/* argument */
62 #define	REBOOT_TYPE	-1
63 #define	HOST_TYPE	-2
64 #define	TTY_TYPE	-3
65 #define	USER_TYPE	-4
66 	int	type;				/* type of arg */
67 	struct arg	*next;			/* linked list pointer */
68 } ARG;
69 static ARG	*arglist;			/* head of linked list */
70 
71 static SLIST_HEAD(, idtab) idlist;
72 
73 struct idtab {
74 	time_t	logout;				/* log out time */
75 	char	id[sizeof ((struct utmpx *)0)->ut_id]; /* identifier */
76 	SLIST_ENTRY(idtab) list;
77 };
78 
79 static const	char *crmsg;			/* cause of last reboot */
80 static time_t	currentout;			/* current logout value */
81 static long	maxrec;				/* records to display */
82 static const	char *file = NULL;		/* utx.log file */
83 static int	sflag = 0;			/* show delta in seconds */
84 static int	width = 5;			/* show seconds in delta */
85 static int	yflag;				/* show year */
86 static int      d_first;
87 static int	snapfound = 0;			/* found snapshot entry? */
88 static time_t	snaptime;			/* if != 0, we will only
89 						 * report users logged in
90 						 * at this snapshot time
91 						 */
92 
93 static void	 addarg(int, char *);
94 static time_t	 dateconv(char *);
95 static void	 doentry(struct utmpx *);
96 static void	 hostconv(char *);
97 static void	 printentry(struct utmpx *, struct idtab *);
98 static char	*ttyconv(char *);
99 static int	 want(struct utmpx *);
100 static void	 usage(void);
101 static void	 wtmp(void);
102 
103 static void
104 usage(void)
105 {
106 	xo_error(
107 "usage: last [-swy] [-d [[CC]YY][MMDD]hhmm[.SS]] [-f file] [-h host]\n"
108 "            [-n maxrec] [-t tty] [user ...]\n");
109 	exit(1);
110 }
111 
112 int
113 main(int argc, char *argv[])
114 {
115 	int ch;
116 	char *p;
117 
118 	(void) setlocale(LC_TIME, "");
119 	d_first = (*nl_langinfo(D_MD_ORDER) == 'd');
120 
121 	argc = xo_parse_args(argc, argv);
122 	if (argc < 0)
123 		exit(1);
124 	atexit(xo_finish_atexit);
125 
126 	maxrec = -1;
127 	snaptime = 0;
128 	while ((ch = getopt(argc, argv, "0123456789d:f:h:n:st:wy")) != -1)
129 		switch (ch) {
130 		case '0': case '1': case '2': case '3': case '4':
131 		case '5': case '6': case '7': case '8': case '9':
132 			/*
133 			 * kludge: last was originally designed to take
134 			 * a number after a dash.
135 			 */
136 			if (maxrec == -1) {
137 				p = strchr(argv[optind - 1], ch);
138 				if (p == NULL)
139 					p = strchr(argv[optind], ch);
140 				maxrec = atol(p);
141 				if (!maxrec)
142 					exit(0);
143 			}
144 			break;
145 		case 'd':
146 			snaptime = dateconv(optarg);
147 			break;
148 		case 'f':
149 			file = optarg;
150 			break;
151 		case 'h':
152 			hostconv(optarg);
153 			addarg(HOST_TYPE, optarg);
154 			break;
155 		case 'n':
156 			errno = 0;
157 			maxrec = strtol(optarg, &p, 10);
158 			if (p == optarg || *p != '\0' || errno != 0 ||
159 			    maxrec <= 0)
160 				xo_errx(1, "%s: bad line count", optarg);
161 			break;
162 		case 's':
163 			sflag++;	/* Show delta as seconds */
164 			break;
165 		case 't':
166 			addarg(TTY_TYPE, ttyconv(optarg));
167 			break;
168 		case 'w':
169 			width = 8;
170 			break;
171 		case 'y':
172 			yflag++;
173 			break;
174 		case '?':
175 		default:
176 			usage();
177 		}
178 
179 	if (caph_limit_stdio() < 0)
180 		xo_err(1, "can't limit stdio rights");
181 
182 	caph_cache_catpages();
183 	caph_cache_tzdata();
184 
185 	/* Cache UTX database. */
186 	if (setutxdb(UTXDB_LOG, file) != 0)
187 		xo_err(1, "%s", file != NULL ? file : "(default utx db)");
188 
189 	if (caph_enter() < 0)
190 		xo_err(1, "cap_enter");
191 
192 	if (sflag && width == 8) usage();
193 
194 	if (argc) {
195 		setlinebuf(stdout);
196 		for (argv += optind; *argv; ++argv) {
197 			if (strcmp(*argv, "reboot") == 0)
198 				addarg(REBOOT_TYPE, *argv);
199 #define	COMPATIBILITY
200 #ifdef	COMPATIBILITY
201 			/* code to allow "last p5" to work */
202 			addarg(TTY_TYPE, ttyconv(*argv));
203 #endif
204 			addarg(USER_TYPE, *argv);
205 		}
206 	}
207 	wtmp();
208 	exit(0);
209 }
210 
211 /*
212  * wtmp --
213  *	read through the utx.log file
214  */
215 static void
216 wtmp(void)
217 {
218 	struct utmpx *buf = NULL;
219 	struct utmpx *ut;
220 	static unsigned int amount = 0;
221 	time_t t;
222 	char ct[80];
223 	struct tm *tm;
224 
225 	SLIST_INIT(&idlist);
226 	(void)time(&t);
227 
228 	xo_open_container("last-information");
229 
230 	/* Load the last entries from the file. */
231 	while ((ut = getutxent()) != NULL) {
232 		if (amount % 128 == 0) {
233 			buf = realloc(buf, (amount + 128) * sizeof *ut);
234 			if (buf == NULL)
235 				xo_err(1, "realloc");
236 		}
237 		memcpy(&buf[amount++], ut, sizeof *ut);
238 		if (t > ut->ut_tv.tv_sec)
239 			t = ut->ut_tv.tv_sec;
240 	}
241 	endutxent();
242 
243 	/* Display them in reverse order. */
244 	xo_open_list("last");
245 	while (amount > 0)
246 		doentry(&buf[--amount]);
247 	xo_close_list("last");
248 	free(buf);
249 	tm = localtime(&t);
250 	(void) strftime(ct, sizeof(ct), "%+", tm);
251 	xo_emit("\n{:utxdb/%s}", (file == NULL) ? "utx.log" : file);
252 	xo_attr("seconds", "%lu", (unsigned long) t);
253 	xo_emit(" begins {:begins/%hs}\n", ct);
254 	xo_close_container("last-information");
255 }
256 
257 /*
258  * doentry --
259  *	process a single utx.log entry
260  */
261 static void
262 doentry(struct utmpx *bp)
263 {
264 	struct idtab *tt;
265 
266 	/* the machine stopped */
267 	if (bp->ut_type == BOOT_TIME || bp->ut_type == SHUTDOWN_TIME) {
268 		/* everybody just logged out */
269 		while ((tt = SLIST_FIRST(&idlist)) != NULL) {
270 			SLIST_REMOVE_HEAD(&idlist, list);
271 			free(tt);
272 		}
273 		currentout = -bp->ut_tv.tv_sec;
274 		crmsg = bp->ut_type != SHUTDOWN_TIME ?
275 		    "crash" : "shutdown";
276 		/*
277 		 * if we're in snapshot mode, we want to exit if this
278 		 * shutdown/reboot appears while we are tracking the
279 		 * active range
280 		 */
281 		if (snaptime && snapfound)
282 			exit(0);
283 		/*
284 		 * don't print shutdown/reboot entries unless flagged for
285 		 */
286 		if (!snaptime && want(bp))
287 			printentry(bp, NULL);
288 		return;
289 	}
290 	/* date got set */
291 	if (bp->ut_type == OLD_TIME || bp->ut_type == NEW_TIME) {
292 		if (want(bp) && !snaptime)
293 			printentry(bp, NULL);
294 		return;
295 	}
296 
297 	if (bp->ut_type != USER_PROCESS && bp->ut_type != DEAD_PROCESS)
298 		return;
299 
300 	/* find associated identifier */
301 	SLIST_FOREACH(tt, &idlist, list)
302 	    if (!memcmp(tt->id, bp->ut_id, sizeof bp->ut_id))
303 		    break;
304 
305 	if (tt == NULL) {
306 		/* add new one */
307 		tt = malloc(sizeof(struct idtab));
308 		if (tt == NULL)
309 			xo_errx(1, "malloc failure");
310 		tt->logout = currentout;
311 		memcpy(tt->id, bp->ut_id, sizeof bp->ut_id);
312 		SLIST_INSERT_HEAD(&idlist, tt, list);
313 	}
314 
315 	/*
316 	 * print record if not in snapshot mode and wanted
317 	 * or in snapshot mode and in snapshot range
318 	 */
319 	if (bp->ut_type == USER_PROCESS && (want(bp) ||
320 	    (bp->ut_tv.tv_sec < snaptime &&
321 	    (tt->logout > snaptime || tt->logout < 1)))) {
322 		snapfound = 1;
323 		printentry(bp, tt);
324 	}
325 	tt->logout = bp->ut_tv.tv_sec;
326 }
327 
328 /*
329  * printentry --
330  *	output an entry
331  *
332  * If `tt' is non-NULL, use it and `crmsg' to print the logout time or
333  * logout type (crash/shutdown) as appropriate.
334  */
335 static void
336 printentry(struct utmpx *bp, struct idtab *tt)
337 {
338 	char ct[80];
339 	struct tm *tm;
340 	time_t	delta;				/* time difference */
341 	time_t	t;
342 
343 	if (maxrec != -1 && !maxrec--)
344 		exit(0);
345 	xo_open_instance("last");
346 	t = bp->ut_tv.tv_sec;
347 	tm = localtime(&t);
348 	(void) strftime(ct, sizeof(ct), d_first ?
349 	    (yflag ? "%a %e %b %Y %R" : "%a %e %b %R") :
350 	    (yflag ? "%a %b %e %Y %R" : "%a %b %e %R"), tm);
351 	switch (bp->ut_type) {
352 	case BOOT_TIME:
353 		xo_emit("{:user/%-42s/%s}", "boot time");
354 		break;
355 	case SHUTDOWN_TIME:
356 		xo_emit("{:user/%-42s/%s}", "shutdown time");
357 		break;
358 	case OLD_TIME:
359 		xo_emit("{:user/%-42s/%s}", "old time");
360 		break;
361 	case NEW_TIME:
362 		xo_emit("{:user/%-42s/%s}", "new time");
363 		break;
364 	case USER_PROCESS:
365 		xo_emit("{:user/%-10s/%s} {:tty/%-8s/%s} {:from/%-22.22s/%s}",
366 		    bp->ut_user, bp->ut_line, bp->ut_host);
367 		break;
368 	}
369 	xo_attr("seconds", "%lu", (unsigned long)t);
370 	xo_emit(" {:login-time/%hs%c/%s}", ct, tt == NULL ? '\n' : ' ');
371 	if (tt == NULL)
372 		goto end;
373 	if (!tt->logout) {
374 		xo_emit("  {:logout-time/still logged in}\n");
375 		goto end;
376 	}
377 	if (tt->logout < 0) {
378 		tt->logout = -tt->logout;
379 		xo_emit("- {:logout-reason/%s}", crmsg);
380 	} else {
381 		tm = localtime(&tt->logout);
382 		(void) strftime(ct, sizeof(ct), "%R", tm);
383 		xo_attr("seconds", "%lu", (unsigned long)tt->logout);
384 		xo_emit("- {:logout-time/%s}", ct);
385 	}
386 	delta = tt->logout - bp->ut_tv.tv_sec;
387 	xo_attr("seconds", "%ld", (long)delta);
388 	if (sflag) {
389 		xo_emit("  ({:session-length/%8ld})\n", (long)delta);
390 	} else {
391 		tm = gmtime(&delta);
392 		(void) strftime(ct, sizeof(ct), width >= 8 ? "%T" : "%R", tm);
393 		if (delta < 86400)
394 			xo_emit("  ({:session-length/%s})\n", ct);
395 		else
396 			xo_emit(" ({:session-length/%ld+%s})\n",
397 			    (long)delta / 86400, ct);
398 	}
399 
400 end:
401 	xo_close_instance("last");
402 }
403 
404 /*
405  * want --
406  *	see if want this entry
407  */
408 static int
409 want(struct utmpx *bp)
410 {
411 	ARG *step;
412 
413 	if (snaptime)
414 		return (NO);
415 
416 	if (!arglist)
417 		return (YES);
418 
419 	for (step = arglist; step; step = step->next)
420 		switch(step->type) {
421 		case REBOOT_TYPE:
422 			if (bp->ut_type == BOOT_TIME ||
423 			    bp->ut_type == SHUTDOWN_TIME)
424 				return (YES);
425 			break;
426 		case HOST_TYPE:
427 			if (!strcasecmp(step->name, bp->ut_host))
428 				return (YES);
429 			break;
430 		case TTY_TYPE:
431 			if (!strcmp(step->name, bp->ut_line))
432 				return (YES);
433 			break;
434 		case USER_TYPE:
435 			if (!strcmp(step->name, bp->ut_user))
436 				return (YES);
437 			break;
438 		}
439 	return (NO);
440 }
441 
442 /*
443  * addarg --
444  *	add an entry to a linked list of arguments
445  */
446 static void
447 addarg(int type, char *arg)
448 {
449 	ARG *cur;
450 
451 	if ((cur = malloc(sizeof(ARG))) == NULL)
452 		xo_errx(1, "malloc failure");
453 	cur->next = arglist;
454 	cur->type = type;
455 	cur->name = arg;
456 	arglist = cur;
457 }
458 
459 /*
460  * hostconv --
461  *	convert the hostname to search pattern; if the supplied host name
462  *	has a domain attached that is the same as the current domain, rip
463  *	off the domain suffix since that's what login(1) does.
464  */
465 static void
466 hostconv(char *arg)
467 {
468 	static int first = 1;
469 	static char *hostdot, name[MAXHOSTNAMELEN];
470 	char *argdot;
471 
472 	if (!(argdot = strchr(arg, '.')))
473 		return;
474 	if (first) {
475 		first = 0;
476 		if (gethostname(name, sizeof(name)))
477 			xo_err(1, "gethostname");
478 		hostdot = strchr(name, '.');
479 	}
480 	if (hostdot && !strcasecmp(hostdot, argdot))
481 		*argdot = '\0';
482 }
483 
484 /*
485  * ttyconv --
486  *	convert tty to correct name.
487  */
488 static char *
489 ttyconv(char *arg)
490 {
491 	char *mval;
492 
493 	/*
494 	 * kludge -- we assume that all tty's end with
495 	 * a two character suffix.
496 	 */
497 	if (strlen(arg) == 2) {
498 		/* either 6 for "ttyxx" or 8 for "console" */
499 		if ((mval = malloc(8)) == NULL)
500 			xo_errx(1, "malloc failure");
501 		if (!strcmp(arg, "co"))
502 			(void)strcpy(mval, "console");
503 		else {
504 			(void)strcpy(mval, "tty");
505 			(void)strcpy(mval + 3, arg);
506 		}
507 		return (mval);
508 	}
509 	if (!strncmp(arg, _PATH_DEV, sizeof(_PATH_DEV) - 1))
510 		return (arg + 5);
511 	return (arg);
512 }
513 
514 /*
515  * dateconv --
516  * 	Convert the snapshot time in command line given in the format
517  * 	[[CC]YY]MMDDhhmm[.SS]] to a time_t.
518  * 	Derived from atime_arg1() in usr.bin/touch/touch.c
519  */
520 static time_t
521 dateconv(char *arg)
522 {
523         time_t timet;
524         struct tm *t;
525         int yearset;
526         char *p;
527 
528         /* Start with the current time. */
529         if (time(&timet) < 0)
530                 xo_err(1, "time");
531         if ((t = localtime(&timet)) == NULL)
532                 xo_err(1, "localtime");
533 
534         /* [[CC]YY]MMDDhhmm[.SS] */
535         if ((p = strchr(arg, '.')) == NULL)
536                 t->tm_sec = 0; 		/* Seconds defaults to 0. */
537         else {
538                 if (strlen(p + 1) != 2)
539                         goto terr;
540                 *p++ = '\0';
541                 t->tm_sec = ATOI2(p);
542         }
543 
544         yearset = 0;
545         switch (strlen(arg)) {
546         case 12:                	/* CCYYMMDDhhmm */
547                 t->tm_year = ATOI2(arg);
548                 t->tm_year *= 100;
549                 yearset = 1;
550                 /* FALLTHROUGH */
551         case 10:                	/* YYMMDDhhmm */
552                 if (yearset) {
553                         yearset = ATOI2(arg);
554                         t->tm_year += yearset;
555                 } else {
556                         yearset = ATOI2(arg);
557                         if (yearset < 69)
558                                 t->tm_year = yearset + 2000;
559                         else
560                                 t->tm_year = yearset + 1900;
561                 }
562                 t->tm_year -= 1900;     /* Convert to UNIX time. */
563                 /* FALLTHROUGH */
564         case 8:				/* MMDDhhmm */
565                 t->tm_mon = ATOI2(arg);
566                 --t->tm_mon;    	/* Convert from 01-12 to 00-11 */
567                 t->tm_mday = ATOI2(arg);
568                 t->tm_hour = ATOI2(arg);
569                 t->tm_min = ATOI2(arg);
570                 break;
571         case 4:				/* hhmm */
572                 t->tm_hour = ATOI2(arg);
573                 t->tm_min = ATOI2(arg);
574                 break;
575         default:
576                 goto terr;
577         }
578         t->tm_isdst = -1;       	/* Figure out DST. */
579         timet = mktime(t);
580         if (timet == -1)
581 terr:           xo_errx(1,
582         "out of range or illegal time specification: [[CC]YY]MMDDhhmm[.SS]");
583         return timet;
584 }
585