xref: /freebsd/bin/date/date.c (revision 8aac90f18aef7c9eea906c3ff9a001ca7b94f375)
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 
54 static void badformat(void);
55 static void iso8601_usage(const char *) __dead2;
56 static void multipleformats(void);
57 static void printdate(const char *);
58 static void printisodate(struct tm *, long);
59 static void setthetime(const char *, const char *, int, struct timespec *);
60 static size_t strftime_ns(char * __restrict, size_t, const char * __restrict,
61     const struct tm * __restrict, long);
62 static void usage(void) __dead2;
63 
64 static 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 };
74 static const struct iso8601_fmt *iso8601_selected;
75 
76 static const char *rfc2822_format = "%a, %d %b %Y %T %z";
77 
78 int
79 main(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 
215 static void
216 printdate(const char *buf)
217 {
218 	(void)printf("%s\n", buf);
219 	if (fflush(stdout))
220 		err(1, "stdout");
221 	exit(EXIT_SUCCESS);
222 }
223 
224 static void
225 printisodate(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 
248 static void
249 setthetime(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  */
371 static size_t
372 strftime_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 
436 static void
437 badformat(void)
438 {
439 	warnx("illegal time format");
440 	usage();
441 }
442 
443 static void
444 iso8601_usage(const char *badarg)
445 {
446 	errx(1, "invalid argument '%s' for -I", badarg);
447 }
448 
449 static void
450 multipleformats(void)
451 {
452 	errx(1, "multiple output formats specified");
453 }
454 
455 static void
456 usage(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