1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1985, 1987, 1988, 1993
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/param.h>
33#include <sys/time.h>
34#include <sys/stat.h>
35
36#include <ctype.h>
37#include <err.h>
38#include <errno.h>
39#include <locale.h>
40#include <stdbool.h>
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44#include <syslog.h>
45#include <unistd.h>
46#include <utmpx.h>
47
48#include "vary.h"
49
50#ifndef	TM_YEAR_BASE
51#define	TM_YEAR_BASE	1900
52#endif
53
54static void badformat(void);
55static void iso8601_usage(const char *) __dead2;
56static void multipleformats(void);
57static void printdate(const char *);
58static void printisodate(struct tm *, long);
59static void setthetime(const char *, const char *, int, struct timespec *);
60static size_t strftime_ns(char * __restrict, size_t, const char * __restrict,
61    const struct tm * __restrict, long);
62static void usage(void) __dead2;
63
64static const struct iso8601_fmt {
65	const char *refname;
66	const char *format_string;
67} iso8601_fmts[] = {
68	{ "date", "%Y-%m-%d" },
69	{ "hours", "T%H" },
70	{ "minutes", ":%M" },
71	{ "seconds", ":%S" },
72	{ "ns", ",%N" },
73};
74static const struct iso8601_fmt *iso8601_selected;
75
76static const char *rfc2822_format = "%a, %d %b %Y %T %z";
77
78int
79main(int argc, char *argv[])
80{
81	struct timespec ts;
82	int ch, rflag;
83	bool Iflag, jflag, Rflag;
84	const char *format;
85	char buf[1024];
86	char *fmt, *outzone = NULL;
87	char *tmp;
88	struct vary *v;
89	const struct vary *badv;
90	struct tm *lt;
91	struct stat sb;
92	size_t i;
93
94	v = NULL;
95	fmt = NULL;
96	(void) setlocale(LC_TIME, "");
97	rflag = 0;
98	Iflag = jflag = Rflag = 0;
99	ts.tv_sec = 0;
100	ts.tv_nsec = 0;
101	while ((ch = getopt(argc, argv, "f:I::jnRr:uv:z:")) != -1)
102		switch((char)ch) {
103		case 'f':
104			fmt = optarg;
105			break;
106		case 'I':
107			if (Rflag)
108				multipleformats();
109			Iflag = 1;
110			if (optarg == NULL) {
111				iso8601_selected = iso8601_fmts;
112				break;
113			}
114			for (i = 0; i < nitems(iso8601_fmts); i++)
115				if (strcmp(optarg, iso8601_fmts[i].refname) == 0)
116					break;
117			if (i == nitems(iso8601_fmts))
118				iso8601_usage(optarg);
119
120			iso8601_selected = &iso8601_fmts[i];
121			break;
122		case 'j':
123			jflag = 1;	/* don't set time */
124			break;
125		case 'n':
126			break;
127		case 'R':		/* RFC 2822 datetime format */
128			if (Iflag)
129				multipleformats();
130			Rflag = 1;
131			break;
132		case 'r':		/* user specified seconds */
133			rflag = 1;
134			ts.tv_sec = strtoq(optarg, &tmp, 0);
135			if (*tmp != 0) {
136				if (stat(optarg, &sb) == 0) {
137					ts.tv_sec = sb.st_mtim.tv_sec;
138					ts.tv_nsec = sb.st_mtim.tv_nsec;
139				} else
140					usage();
141			}
142			break;
143		case 'u':		/* do everything in UTC */
144			(void)setenv("TZ", "UTC0", 1);
145			break;
146		case 'z':
147			outzone = optarg;
148			break;
149		case 'v':
150			v = vary_append(v, optarg);
151			break;
152		default:
153			usage();
154		}
155	argc -= optind;
156	argv += optind;
157
158	if (!rflag && clock_gettime(CLOCK_REALTIME, &ts) == -1)
159		err(1, "clock_gettime");
160
161	format = "%+";
162
163	if (Rflag)
164		format = rfc2822_format;
165
166	/* allow the operands in any order */
167	if (*argv && **argv == '+') {
168		if (Iflag)
169			multipleformats();
170		format = *argv + 1;
171		++argv;
172	}
173
174	if (*argv) {
175		setthetime(fmt, *argv, jflag, &ts);
176		++argv;
177	} else if (fmt != NULL)
178		usage();
179
180	if (*argv && **argv == '+') {
181		if (Iflag)
182			multipleformats();
183		format = *argv + 1;
184	}
185
186	if (outzone != NULL && setenv("TZ", outzone, 1) != 0)
187		err(1, "setenv(TZ)");
188	lt = localtime(&ts.tv_sec);
189	if (lt == NULL)
190		errx(1, "invalid time");
191	badv = vary_apply(v, lt);
192	if (badv) {
193		fprintf(stderr, "%s: Cannot apply date adjustment\n",
194			badv->arg);
195		vary_destroy(v);
196		usage();
197	}
198	vary_destroy(v);
199
200	if (Iflag)
201		printisodate(lt, ts.tv_nsec);
202
203	if (format == rfc2822_format)
204		/*
205		 * When using RFC 2822 datetime format, don't honor the
206		 * locale.
207		 */
208		setlocale(LC_TIME, "C");
209
210
211	(void)strftime_ns(buf, sizeof(buf), format, lt, ts.tv_nsec);
212	printdate(buf);
213}
214
215static void
216printdate(const char *buf)
217{
218	(void)printf("%s\n", buf);
219	if (fflush(stdout))
220		err(1, "stdout");
221	exit(EXIT_SUCCESS);
222}
223
224static void
225printisodate(struct tm *lt, long nsec)
226{
227	const struct iso8601_fmt *it;
228	char fmtbuf[64], buf[64], tzbuf[8];
229
230	fmtbuf[0] = 0;
231	for (it = iso8601_fmts; it <= iso8601_selected; it++)
232		strlcat(fmtbuf, it->format_string, sizeof(fmtbuf));
233
234	(void)strftime_ns(buf, sizeof(buf), fmtbuf, lt, nsec);
235
236	if (iso8601_selected > iso8601_fmts) {
237		(void)strftime_ns(tzbuf, sizeof(tzbuf), "%z", lt, nsec);
238		memmove(&tzbuf[4], &tzbuf[3], 3);
239		tzbuf[3] = ':';
240		strlcat(buf, tzbuf, sizeof(buf));
241	}
242
243	printdate(buf);
244}
245
246#define	ATOI2(s)	((s) += 2, ((s)[-2] - '0') * 10 + ((s)[-1] - '0'))
247
248static void
249setthetime(const char *fmt, const char *p, int jflag, struct timespec *ts)
250{
251	struct utmpx utx;
252	struct tm *lt;
253	const char *dot, *t;
254	int century;
255
256	lt = localtime(&ts->tv_sec);
257	if (lt == NULL)
258		errx(1, "invalid time");
259	lt->tm_isdst = -1;		/* divine correct DST */
260
261	if (fmt != NULL) {
262		t = strptime(p, fmt, lt);
263		if (t == NULL) {
264			fprintf(stderr, "Failed conversion of ``%s''"
265				" using format ``%s''\n", p, fmt);
266			badformat();
267		} else if (*t != '\0')
268			fprintf(stderr, "Warning: Ignoring %ld extraneous"
269				" characters in date string (%s)\n",
270				(long) strlen(t), t);
271	} else {
272		for (t = p, dot = NULL; *t; ++t) {
273			if (isdigit(*t))
274				continue;
275			if (*t == '.' && dot == NULL) {
276				dot = t;
277				continue;
278			}
279			badformat();
280		}
281
282		if (dot != NULL) {			/* .ss */
283			dot++; /* *dot++ = '\0'; */
284			if (strlen(dot) != 2)
285				badformat();
286			lt->tm_sec = ATOI2(dot);
287			if (lt->tm_sec > 61)
288				badformat();
289		} else
290			lt->tm_sec = 0;
291
292		century = 0;
293		/* if p has a ".ss" field then let's pretend it's not there */
294		switch (strlen(p) - ((dot != NULL) ? 3 : 0)) {
295		case 12:				/* cc */
296			lt->tm_year = ATOI2(p) * 100 - TM_YEAR_BASE;
297			century = 1;
298			/* FALLTHROUGH */
299		case 10:				/* yy */
300			if (century)
301				lt->tm_year += ATOI2(p);
302			else {
303				lt->tm_year = ATOI2(p);
304				if (lt->tm_year < 69)	/* hack for 2000 ;-} */
305					lt->tm_year += 2000 - TM_YEAR_BASE;
306				else
307					lt->tm_year += 1900 - TM_YEAR_BASE;
308			}
309			/* FALLTHROUGH */
310		case 8:					/* mm */
311			lt->tm_mon = ATOI2(p);
312			if (lt->tm_mon > 12)
313				badformat();
314			--lt->tm_mon;		/* time struct is 0 - 11 */
315			/* FALLTHROUGH */
316		case 6:					/* dd */
317			lt->tm_mday = ATOI2(p);
318			if (lt->tm_mday > 31)
319				badformat();
320			/* FALLTHROUGH */
321		case 4:					/* HH */
322			lt->tm_hour = ATOI2(p);
323			if (lt->tm_hour > 23)
324				badformat();
325			/* FALLTHROUGH */
326		case 2:					/* MM */
327			lt->tm_min = ATOI2(p);
328			if (lt->tm_min > 59)
329				badformat();
330			break;
331		default:
332			badformat();
333		}
334	}
335
336	/* convert broken-down time to GMT clock time */
337	lt->tm_yday = -1;
338	ts->tv_sec = mktime(lt);
339	if (lt->tm_yday == -1)
340		errx(1, "nonexistent time");
341	ts->tv_nsec = 0;
342
343	if (!jflag) {
344		utx.ut_type = OLD_TIME;
345		memset(utx.ut_id, 0, sizeof(utx.ut_id));
346		(void)gettimeofday(&utx.ut_tv, NULL);
347		pututxline(&utx);
348		if (clock_settime(CLOCK_REALTIME, ts) != 0)
349			err(1, "clock_settime");
350		utx.ut_type = NEW_TIME;
351		(void)gettimeofday(&utx.ut_tv, NULL);
352		pututxline(&utx);
353
354		if ((p = getlogin()) == NULL)
355			p = "???";
356		syslog(LOG_AUTH | LOG_NOTICE, "date set by %s", p);
357	}
358}
359
360/*
361 * The strftime_ns function is a wrapper around strftime(3), which adds support
362 * for features absent from strftime(3). Currently, the only extra feature is
363 * support for %N, the nanosecond conversion specification.
364 *
365 * The functions scans the format string for the non-standard conversion
366 * specifications and replaces them with the date and time values before
367 * passing the format string to strftime(3). The handling of the non-standard
368 * conversion specifications happens before the call to strftime(3) to handle
369 * cases like "%%N" correctly ("%%N" should yield "%N" instead of nanoseconds).
370 */
371static size_t
372strftime_ns(char * __restrict s, size_t maxsize, const char * __restrict format,
373    const struct tm * __restrict t, long nsec)
374{
375	size_t prefixlen;
376	size_t ret;
377	char *newformat;
378	char *oldformat;
379	const char *prefix;
380	const char *suffix;
381	const char *tok;
382	bool seen_percent;
383
384	seen_percent = false;
385	if (asprintf(&newformat, "%s", format) < 0)
386		err(1, "asprintf");
387	tok = newformat;
388	for (tok = newformat; *tok != '\0'; tok++) {
389		switch (*tok) {
390		case '%':
391			/*
392			 * If the previous token was a percent sign,
393			 * then there are two percent tokens in a row.
394			 */
395			if (seen_percent)
396				seen_percent = false;
397			else
398				seen_percent = true;
399			break;
400		case 'N':
401			if (seen_percent) {
402				oldformat = newformat;
403				prefix = oldformat;
404				prefixlen = tok - oldformat - 1;
405				suffix = tok + 1;
406				/*
407				 * Construct a new format string from the
408				 * prefix (i.e., the part of the old fromat
409				 * from its beginning to the currently handled
410				 * "%N" conversion specification, the
411				 * nanoseconds, and the suffix (i.e., the part
412				 * of the old format from the next token to the
413				 * end).
414				 */
415				if (asprintf(&newformat, "%.*s%.9ld%s",
416				    (int)prefixlen, prefix, nsec,
417				    suffix) < 0) {
418					err(1, "asprintf");
419				}
420				free(oldformat);
421				tok = newformat + prefixlen + 9;
422			}
423			seen_percent = false;
424			break;
425		default:
426			seen_percent = false;
427			break;
428		}
429	}
430
431	ret = strftime(s, maxsize, newformat, t);
432	free(newformat);
433	return (ret);
434}
435
436static void
437badformat(void)
438{
439	warnx("illegal time format");
440	usage();
441}
442
443static void
444iso8601_usage(const char *badarg)
445{
446	errx(1, "invalid argument '%s' for -I", badarg);
447}
448
449static void
450multipleformats(void)
451{
452	errx(1, "multiple output formats specified");
453}
454
455static void
456usage(void)
457{
458	(void)fprintf(stderr, "%s\n%s\n%s\n",
459	    "usage: date [-jnRu] [-I[date|hours|minutes|seconds|ns]] [-f input_fmt]",
460	    "            "
461	    "[ -z output_zone ] [-r filename|seconds] [-v[+|-]val[y|m|w|d|H|M|S]]",
462	    "            "
463	    "[[[[[[cc]yy]mm]dd]HH]MM[.SS] | new_date] [+output_fmt]"
464	    );
465	exit(1);
466}
467