1/*
2 * Copyright (c) 1989 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * Copyright (c) 2011 The FreeBSD Foundation
6 * All rights reserved.
7 * Portions of this software were developed by David Chisnall
8 * under sponsorship from the FreeBSD Foundation.
9 *
10 * Redistribution and use in source and binary forms are permitted
11 * provided that the above copyright notice and this paragraph are
12 * duplicated in all such forms and that any documentation,
13 * advertising materials, and other materials related to such
14 * distribution and use acknowledge that the software was developed
15 * by the University of California, Berkeley. The name of the
16 * University may not be used to endorse or promote products derived
17 * from this software without specific prior written permission.
18 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21 */
22
23#ifndef lint
24#ifndef NOID
25static const char	elsieid[] = "@(#)strftime.3	8.3";
26/*
27 * Based on the UCB version with the ID appearing below.
28 * This is ANSIish only when "multibyte character == plain character".
29 */
30#endif /* !defined NOID */
31#endif /* !defined lint */
32
33#include "namespace.h"
34#include "private.h"
35
36#if defined(LIBC_SCCS) && !defined(lint)
37static const char	sccsid[] = "@(#)strftime.c	5.4 (Berkeley) 3/14/89";
38#endif /* LIBC_SCCS and not lint */
39#include <sys/cdefs.h>
40__FBSDID("$FreeBSD$");
41
42#include "tzfile.h"
43#include <fcntl.h>
44#include <sys/stat.h>
45#include "un-namespace.h"
46#include "timelocal.h"
47
48static char *	_add(const char *, char *, const char *);
49static char *	_conv(int, const char *, char *, const char *, locale_t);
50static char *	_fmt(const char *, const struct tm *, char *, const char *,
51			int *, locale_t);
52static char *	_yconv(int, int, int, int, char *, const char *, locale_t);
53
54extern char *	tzname[];
55
56#ifndef YEAR_2000_NAME
57#define YEAR_2000_NAME	"CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
58#endif /* !defined YEAR_2000_NAME */
59
60#define	IN_NONE	0
61#define	IN_SOME	1
62#define	IN_THIS	2
63#define	IN_ALL	3
64
65#define	PAD_DEFAULT	0
66#define	PAD_LESS	1
67#define	PAD_SPACE	2
68#define	PAD_ZERO	3
69
70static const char fmt_padding[][4][5] = {
71	/* DEFAULT,	LESS,	SPACE,	ZERO */
72#define	PAD_FMT_MONTHDAY	0
73#define	PAD_FMT_HMS		0
74#define	PAD_FMT_CENTURY		0
75#define	PAD_FMT_SHORTYEAR	0
76#define	PAD_FMT_MONTH		0
77#define	PAD_FMT_WEEKOFYEAR	0
78#define	PAD_FMT_DAYOFMONTH	0
79	{ "%02d",	"%d",	"%2d",	"%02d" },
80#define	PAD_FMT_SDAYOFMONTH	1
81#define	PAD_FMT_SHMS		1
82	{ "%2d",	"%d",	"%2d",	"%02d" },
83#define	PAD_FMT_DAYOFYEAR	2
84	{ "%03d",	"%d",	"%3d",	"%03d" },
85#define	PAD_FMT_YEAR		3
86	{ "%04d",	"%d",	"%4d",	"%04d" }
87};
88
89size_t
90strftime_l(char * __restrict s, size_t maxsize, const char * __restrict format,
91    const struct tm * __restrict t, locale_t loc)
92{
93	char *	p;
94	int	warn;
95	FIX_LOCALE(loc);
96
97	tzset();
98	warn = IN_NONE;
99	p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn, loc);
100#ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
101	if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
102		(void) fprintf_l(stderr, loc, "\n");
103		if (format == NULL)
104			(void) fputs("NULL strftime format ", stderr);
105		else	(void) fprintf_l(stderr, loc, "strftime format \"%s\" ",
106				format);
107		(void) fputs("yields only two digits of years in ", stderr);
108		if (warn == IN_SOME)
109			(void) fputs("some locales", stderr);
110		else if (warn == IN_THIS)
111			(void) fputs("the current locale", stderr);
112		else	(void) fputs("all locales", stderr);
113		(void) fputs("\n", stderr);
114	}
115#endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
116	if (p == s + maxsize)
117		return (0);
118	*p = '\0';
119	return p - s;
120}
121
122size_t
123strftime(char * __restrict s, size_t maxsize, const char * __restrict format,
124    const struct tm * __restrict t)
125{
126	return strftime_l(s, maxsize, format, t, __get_locale());
127}
128
129static char *
130_fmt(format, t, pt, ptlim, warnp, loc)
131const char *		format;
132const struct tm * const	t;
133char *			pt;
134const char * const	ptlim;
135int *			warnp;
136locale_t	loc;
137{
138	int Ealternative, Oalternative, PadIndex;
139	struct lc_time_T *tptr = __get_current_time_locale(loc);
140
141	for ( ; *format; ++format) {
142		if (*format == '%') {
143			Ealternative = 0;
144			Oalternative = 0;
145			PadIndex	 = PAD_DEFAULT;
146label:
147			switch (*++format) {
148			case '\0':
149				--format;
150				break;
151			case 'A':
152				pt = _add((t->tm_wday < 0 ||
153					t->tm_wday >= DAYSPERWEEK) ?
154					"?" : tptr->weekday[t->tm_wday],
155					pt, ptlim);
156				continue;
157			case 'a':
158				pt = _add((t->tm_wday < 0 ||
159					t->tm_wday >= DAYSPERWEEK) ?
160					"?" : tptr->wday[t->tm_wday],
161					pt, ptlim);
162				continue;
163			case 'B':
164				pt = _add((t->tm_mon < 0 ||
165					t->tm_mon >= MONSPERYEAR) ?
166					"?" : (Oalternative ? tptr->alt_month :
167					tptr->month)[t->tm_mon],
168					pt, ptlim);
169				continue;
170			case 'b':
171			case 'h':
172				pt = _add((t->tm_mon < 0 ||
173					t->tm_mon >= MONSPERYEAR) ?
174					"?" : tptr->mon[t->tm_mon],
175					pt, ptlim);
176				continue;
177			case 'C':
178				/*
179				 * %C used to do a...
180				 *	_fmt("%a %b %e %X %Y", t);
181				 * ...whereas now POSIX 1003.2 calls for
182				 * something completely different.
183				 * (ado, 1993-05-24)
184				 */
185				pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
186					pt, ptlim, loc);
187				continue;
188			case 'c':
189				{
190				int warn2 = IN_SOME;
191
192				pt = _fmt(tptr->c_fmt, t, pt, ptlim, &warn2, loc);
193				if (warn2 == IN_ALL)
194					warn2 = IN_THIS;
195				if (warn2 > *warnp)
196					*warnp = warn2;
197				}
198				continue;
199			case 'D':
200				pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp, loc);
201				continue;
202			case 'd':
203				pt = _conv(t->tm_mday,
204					fmt_padding[PAD_FMT_DAYOFMONTH][PadIndex],
205					pt, ptlim, loc);
206				continue;
207			case 'E':
208				if (Ealternative || Oalternative)
209					break;
210				Ealternative++;
211				goto label;
212			case 'O':
213				/*
214				 * C99 locale modifiers.
215				 * The sequences
216				 *	%Ec %EC %Ex %EX %Ey %EY
217				 *	%Od %oe %OH %OI %Om %OM
218				 *	%OS %Ou %OU %OV %Ow %OW %Oy
219				 * are supposed to provide alternate
220				 * representations.
221				 *
222				 * FreeBSD extension
223				 *      %OB
224				 */
225				if (Ealternative || Oalternative)
226					break;
227				Oalternative++;
228				goto label;
229			case 'e':
230				pt = _conv(t->tm_mday,
231					fmt_padding[PAD_FMT_SDAYOFMONTH][PadIndex],
232					pt, ptlim, loc);
233				continue;
234			case 'F':
235				pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp, loc);
236				continue;
237			case 'H':
238				pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_HMS][PadIndex],
239					pt, ptlim, loc);
240				continue;
241			case 'I':
242				pt = _conv((t->tm_hour % 12) ?
243					(t->tm_hour % 12) : 12,
244					fmt_padding[PAD_FMT_HMS][PadIndex],
245					pt, ptlim, loc);
246				continue;
247			case 'j':
248				pt = _conv(t->tm_yday + 1,
249					fmt_padding[PAD_FMT_DAYOFYEAR][PadIndex],
250					pt, ptlim, loc);
251				continue;
252			case 'k':
253				/*
254				 * This used to be...
255				 *	_conv(t->tm_hour % 12 ?
256				 *		t->tm_hour % 12 : 12, 2, ' ');
257				 * ...and has been changed to the below to
258				 * match SunOS 4.1.1 and Arnold Robbins'
259				 * strftime version 3.0. That is, "%k" and
260				 * "%l" have been swapped.
261				 * (ado, 1993-05-24)
262				 */
263				pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_SHMS][PadIndex],
264					pt, ptlim, loc);
265				continue;
266#ifdef KITCHEN_SINK
267			case 'K':
268				/*
269				** After all this time, still unclaimed!
270				*/
271				pt = _add("kitchen sink", pt, ptlim);
272				continue;
273#endif /* defined KITCHEN_SINK */
274			case 'l':
275				/*
276				 * This used to be...
277				 *	_conv(t->tm_hour, 2, ' ');
278				 * ...and has been changed to the below to
279				 * match SunOS 4.1.1 and Arnold Robbin's
280				 * strftime version 3.0. That is, "%k" and
281				 * "%l" have been swapped.
282				 * (ado, 1993-05-24)
283				 */
284				pt = _conv((t->tm_hour % 12) ?
285					(t->tm_hour % 12) : 12,
286					fmt_padding[PAD_FMT_SHMS][PadIndex],
287					pt, ptlim, loc);
288				continue;
289			case 'M':
290				pt = _conv(t->tm_min, fmt_padding[PAD_FMT_HMS][PadIndex],
291					pt, ptlim, loc);
292				continue;
293			case 'm':
294				pt = _conv(t->tm_mon + 1,
295					fmt_padding[PAD_FMT_MONTH][PadIndex],
296					pt, ptlim, loc);
297				continue;
298			case 'n':
299				pt = _add("\n", pt, ptlim);
300				continue;
301			case 'p':
302				pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
303					tptr->pm : tptr->am,
304					pt, ptlim);
305				continue;
306			case 'R':
307				pt = _fmt("%H:%M", t, pt, ptlim, warnp, loc);
308				continue;
309			case 'r':
310				pt = _fmt(tptr->ampm_fmt, t, pt, ptlim,
311					warnp, loc);
312				continue;
313			case 'S':
314				pt = _conv(t->tm_sec, fmt_padding[PAD_FMT_HMS][PadIndex],
315					pt, ptlim, loc);
316				continue;
317			case 's':
318				{
319					struct tm	tm;
320					char		buf[INT_STRLEN_MAXIMUM(
321								time_t) + 1];
322					time_t		mkt;
323
324					tm = *t;
325					mkt = mktime(&tm);
326					if (TYPE_SIGNED(time_t))
327						(void) sprintf_l(buf, loc, "%ld",
328							(long) mkt);
329					else	(void) sprintf_l(buf, loc, "%lu",
330							(unsigned long) mkt);
331					pt = _add(buf, pt, ptlim);
332				}
333				continue;
334			case 'T':
335				pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp, loc);
336				continue;
337			case 't':
338				pt = _add("\t", pt, ptlim);
339				continue;
340			case 'U':
341				pt = _conv((t->tm_yday + DAYSPERWEEK -
342					t->tm_wday) / DAYSPERWEEK,
343					fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex],
344					pt, ptlim, loc);
345				continue;
346			case 'u':
347				/*
348				 * From Arnold Robbins' strftime version 3.0:
349				 * "ISO 8601: Weekday as a decimal number
350				 * [1 (Monday) - 7]"
351				 * (ado, 1993-05-24)
352				 */
353				pt = _conv((t->tm_wday == 0) ?
354					DAYSPERWEEK : t->tm_wday,
355					"%d", pt, ptlim, loc);
356				continue;
357			case 'V':	/* ISO 8601 week number */
358			case 'G':	/* ISO 8601 year (four digits) */
359			case 'g':	/* ISO 8601 year (two digits) */
360/*
361 * From Arnold Robbins' strftime version 3.0: "the week number of the
362 * year (the first Monday as the first day of week 1) as a decimal number
363 * (01-53)."
364 * (ado, 1993-05-24)
365 *
366 * From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
367 * "Week 01 of a year is per definition the first week which has the
368 * Thursday in this year, which is equivalent to the week which contains
369 * the fourth day of January. In other words, the first week of a new year
370 * is the week which has the majority of its days in the new year. Week 01
371 * might also contain days from the previous year and the week before week
372 * 01 of a year is the last week (52 or 53) of the previous year even if
373 * it contains days from the new year. A week starts with Monday (day 1)
374 * and ends with Sunday (day 7). For example, the first week of the year
375 * 1997 lasts from 1996-12-30 to 1997-01-05..."
376 * (ado, 1996-01-02)
377 */
378				{
379					int	year;
380					int	base;
381					int	yday;
382					int	wday;
383					int	w;
384
385					year = t->tm_year;
386					base = TM_YEAR_BASE;
387					yday = t->tm_yday;
388					wday = t->tm_wday;
389					for ( ; ; ) {
390						int	len;
391						int	bot;
392						int	top;
393
394						len = isleap_sum(year, base) ?
395							DAYSPERLYEAR :
396							DAYSPERNYEAR;
397						/*
398						 * What yday (-3 ... 3) does
399						 * the ISO year begin on?
400						 */
401						bot = ((yday + 11 - wday) %
402							DAYSPERWEEK) - 3;
403						/*
404						 * What yday does the NEXT
405						 * ISO year begin on?
406						 */
407						top = bot -
408							(len % DAYSPERWEEK);
409						if (top < -3)
410							top += DAYSPERWEEK;
411						top += len;
412						if (yday >= top) {
413							++base;
414							w = 1;
415							break;
416						}
417						if (yday >= bot) {
418							w = 1 + ((yday - bot) /
419								DAYSPERWEEK);
420							break;
421						}
422						--base;
423						yday += isleap_sum(year, base) ?
424							DAYSPERLYEAR :
425							DAYSPERNYEAR;
426					}
427#ifdef XPG4_1994_04_09
428					if ((w == 52 &&
429						t->tm_mon == TM_JANUARY) ||
430						(w == 1 &&
431						t->tm_mon == TM_DECEMBER))
432							w = 53;
433#endif /* defined XPG4_1994_04_09 */
434					if (*format == 'V')
435						pt = _conv(w, fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex],
436							pt, ptlim, loc);
437					else if (*format == 'g') {
438						*warnp = IN_ALL;
439						pt = _yconv(year, base, 0, 1,
440							pt, ptlim, loc);
441					} else	pt = _yconv(year, base, 1, 1,
442							pt, ptlim, loc);
443				}
444				continue;
445			case 'v':
446				/*
447				 * From Arnold Robbins' strftime version 3.0:
448				 * "date as dd-bbb-YYYY"
449				 * (ado, 1993-05-24)
450				 */
451				pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp, loc);
452				continue;
453			case 'W':
454				pt = _conv((t->tm_yday + DAYSPERWEEK -
455					(t->tm_wday ?
456					(t->tm_wday - 1) :
457					(DAYSPERWEEK - 1))) / DAYSPERWEEK,
458					fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex],
459					pt, ptlim, loc);
460				continue;
461			case 'w':
462				pt = _conv(t->tm_wday, "%d", pt, ptlim, loc);
463				continue;
464			case 'X':
465				pt = _fmt(tptr->X_fmt, t, pt, ptlim, warnp, loc);
466				continue;
467			case 'x':
468				{
469				int	warn2 = IN_SOME;
470
471				pt = _fmt(tptr->x_fmt, t, pt, ptlim, &warn2, loc);
472				if (warn2 == IN_ALL)
473					warn2 = IN_THIS;
474				if (warn2 > *warnp)
475					*warnp = warn2;
476				}
477				continue;
478			case 'y':
479				*warnp = IN_ALL;
480				pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
481					pt, ptlim, loc);
482				continue;
483			case 'Y':
484				pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
485					pt, ptlim, loc);
486				continue;
487			case 'Z':
488#ifdef TM_ZONE
489				if (t->TM_ZONE != NULL)
490					pt = _add(t->TM_ZONE, pt, ptlim);
491				else
492#endif /* defined TM_ZONE */
493				if (t->tm_isdst >= 0)
494					pt = _add(tzname[t->tm_isdst != 0],
495						pt, ptlim);
496				/*
497				 * C99 says that %Z must be replaced by the
498				 * empty string if the time zone is not
499				 * determinable.
500				 */
501				continue;
502			case 'z':
503				{
504				int		diff;
505				char const *	sign;
506
507				if (t->tm_isdst < 0)
508					continue;
509#ifdef TM_GMTOFF
510				diff = t->TM_GMTOFF;
511#else /* !defined TM_GMTOFF */
512				/*
513				 * C99 says that the UTC offset must
514				 * be computed by looking only at
515				 * tm_isdst. This requirement is
516				 * incorrect, since it means the code
517				 * must rely on magic (in this case
518				 * altzone and timezone), and the
519				 * magic might not have the correct
520				 * offset. Doing things correctly is
521				 * tricky and requires disobeying C99;
522				 * see GNU C strftime for details.
523				 * For now, punt and conform to the
524				 * standard, even though it's incorrect.
525				 *
526				 * C99 says that %z must be replaced by the
527				 * empty string if the time zone is not
528				 * determinable, so output nothing if the
529				 * appropriate variables are not available.
530				 */
531				if (t->tm_isdst == 0)
532#ifdef USG_COMPAT
533					diff = -timezone;
534#else /* !defined USG_COMPAT */
535					continue;
536#endif /* !defined USG_COMPAT */
537				else
538#ifdef ALTZONE
539					diff = -altzone;
540#else /* !defined ALTZONE */
541					continue;
542#endif /* !defined ALTZONE */
543#endif /* !defined TM_GMTOFF */
544				if (diff < 0) {
545					sign = "-";
546					diff = -diff;
547				} else
548					sign = "+";
549				pt = _add(sign, pt, ptlim);
550				diff /= SECSPERMIN;
551				diff = (diff / MINSPERHOUR) * 100 +
552					(diff % MINSPERHOUR);
553				pt = _conv(diff,
554					fmt_padding[PAD_FMT_YEAR][PadIndex],
555					pt, ptlim, loc);
556				}
557				continue;
558			case '+':
559				pt = _fmt(tptr->date_fmt, t, pt, ptlim,
560					warnp, loc);
561				continue;
562			case '-':
563				if (PadIndex != PAD_DEFAULT)
564					break;
565				PadIndex = PAD_LESS;
566				goto label;
567			case '_':
568				if (PadIndex != PAD_DEFAULT)
569					break;
570				PadIndex = PAD_SPACE;
571				goto label;
572			case '0':
573				if (PadIndex != PAD_DEFAULT)
574					break;
575				PadIndex = PAD_ZERO;
576				goto label;
577			case '%':
578			/*
579			 * X311J/88-090 (4.12.3.5): if conversion char is
580			 * undefined, behavior is undefined. Print out the
581			 * character itself as printf(3) also does.
582			 */
583			default:
584				break;
585			}
586		}
587		if (pt == ptlim)
588			break;
589		*pt++ = *format;
590	}
591	return (pt);
592}
593
594static char *
595_conv(n, format, pt, ptlim, loc)
596const int		n;
597const char * const	format;
598char * const		pt;
599const char * const	ptlim;
600locale_t		loc;
601{
602	char	buf[INT_STRLEN_MAXIMUM(int) + 1];
603
604	(void) sprintf_l(buf, loc, format, n);
605	return _add(buf, pt, ptlim);
606}
607
608static char *
609_add(str, pt, ptlim)
610const char *		str;
611char *			pt;
612const char * const	ptlim;
613{
614	while (pt < ptlim && (*pt = *str++) != '\0')
615		++pt;
616	return (pt);
617}
618
619/*
620 * POSIX and the C Standard are unclear or inconsistent about
621 * what %C and %y do if the year is negative or exceeds 9999.
622 * Use the convention that %C concatenated with %y yields the
623 * same output as %Y, and that %Y contains at least 4 bytes,
624 * with more only if necessary.
625 */
626
627static char *
628_yconv(a, b, convert_top, convert_yy, pt, ptlim, loc)
629const int		a;
630const int		b;
631const int		convert_top;
632const int		convert_yy;
633char *			pt;
634const char * const	ptlim;
635locale_t		loc;
636{
637	register int	lead;
638	register int	trail;
639
640#define	DIVISOR	100
641	trail = a % DIVISOR + b % DIVISOR;
642	lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
643	trail %= DIVISOR;
644	if (trail < 0 && lead > 0) {
645		trail += DIVISOR;
646		--lead;
647	} else if (lead < 0 && trail > 0) {
648		trail -= DIVISOR;
649		++lead;
650	}
651	if (convert_top) {
652		if (lead == 0 && trail < 0)
653			pt = _add("-0", pt, ptlim);
654		else	pt = _conv(lead, "%02d", pt, ptlim, loc);
655	}
656	if (convert_yy)
657		pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt,
658		     ptlim, loc);
659	return (pt);
660}
661