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 * @(#)strftime.c 5.4 (Berkeley) 3/14/89
23 * $FreeBSD: head/lib/libc/stdtime/strftime.c 237211 2012-06-17 21:40:13Z jilles $
24 */
25
26
27 #include "namespace.h"
28 #include "private.h"
29
30 #include "tzfile.h"
31 #include <fcntl.h>
32 #include <sys/stat.h>
33 #include "un-namespace.h"
34 #include "timelocal.h"
35
36 static char * _add(const char *, char *, const char *);
37 static char * _conv(int, const char *, char *, const char *);
38 static char * _fmt(const char *, const struct tm *, char *, const char *,
39 int *, locale_t);
40 static char * _yconv(int, int, int, int, char *, const char *);
41
42 extern char * tzname[];
43
44 #ifndef YEAR_2000_NAME
45 #define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
46 #endif /* !defined YEAR_2000_NAME */
47
48 #define IN_NONE 0
49 #define IN_SOME 1
50 #define IN_THIS 2
51 #define IN_ALL 3
52
53 #define PAD_DEFAULT 0
54 #define PAD_LESS 1
55 #define PAD_SPACE 2
56 #define PAD_ZERO 3
57
58 static const char fmt_padding[][4][5] = {
59 /* DEFAULT, LESS, SPACE, ZERO */
60 #define PAD_FMT_MONTHDAY 0
61 #define PAD_FMT_HMS 0
62 #define PAD_FMT_CENTURY 0
63 #define PAD_FMT_SHORTYEAR 0
64 #define PAD_FMT_MONTH 0
65 #define PAD_FMT_WEEKOFYEAR 0
66 #define PAD_FMT_DAYOFMONTH 0
67 { "%02d", "%d", "%2d", "%02d" },
68 #define PAD_FMT_SDAYOFMONTH 1
69 #define PAD_FMT_SHMS 1
70 { "%2d", "%d", "%2d", "%02d" },
71 #define PAD_FMT_DAYOFYEAR 2
72 { "%03d", "%d", "%3d", "%03d" },
73 #define PAD_FMT_YEAR 3
74 { "%04d", "%d", "%4d", "%04d" }
75 };
76
77 size_t
strftime_l(char * __restrict s,size_t maxsize,const char * __restrict format,const struct tm * __restrict t,locale_t loc)78 strftime_l(char * __restrict s, size_t maxsize, const char * __restrict format,
79 const struct tm * __restrict t, locale_t loc)
80 {
81 char * p;
82 int warn;
83 FIX_LOCALE(loc);
84
85 tzset();
86 warn = IN_NONE;
87 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn, loc);
88 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
89 if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
90 fprintf_l(stderr, loc, "\n");
91 if (format == NULL)
92 fprintf_l(stderr, loc, "NULL strftime format ");
93 else fprintf_l(stderr, loc, "strftime format \"%s\" ",
94 format);
95 fprintf_l(stderr, loc, "yields only two digits of years in ");
96 if (warn == IN_SOME)
97 fprintf_l(stderr, loc, "some locales");
98 else if (warn == IN_THIS)
99 fprintf_l(stderr, loc, "the current locale");
100 else fprintf_l(stderr, loc, "all locales");
101 fprintf_l(stderr, loc, "\n");
102 }
103 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
104 if (p == s + maxsize)
105 return 0;
106 *p = '\0';
107 return p - s;
108 }
109
110 size_t
strftime(char * __restrict s,size_t maxsize,const char * __restrict format,const struct tm * __restrict t)111 strftime(char * __restrict s, size_t maxsize, const char * __restrict format,
112 const struct tm * __restrict t)
113 {
114 return strftime_l(s, maxsize, format, t, __get_locale());
115 }
116
117 static char *
_fmt(const char * format,const struct tm * const t,char * pt,const char * const ptlim,int * warnp,locale_t loc)118 _fmt(const char *format, const struct tm * const t, char *pt,
119 const char * const ptlim, int *warnp, locale_t loc)
120 {
121 int Ealternative, Oalternative, PadIndex;
122 struct lc_time_T *tptr = __get_current_time_locale(loc);
123
124 for ( ; *format; ++format) {
125 if (*format == '%') {
126 Ealternative = 0;
127 Oalternative = 0;
128 PadIndex = PAD_DEFAULT;
129 label:
130 switch (*++format) {
131 case '\0':
132 --format;
133 break;
134 case 'A':
135 pt = _add((t->tm_wday < 0 ||
136 t->tm_wday >= DAYSPERWEEK) ?
137 "?" : tptr->weekday[t->tm_wday],
138 pt, ptlim);
139 continue;
140 case 'a':
141 pt = _add((t->tm_wday < 0 ||
142 t->tm_wday >= DAYSPERWEEK) ?
143 "?" : tptr->wday[t->tm_wday],
144 pt, ptlim);
145 continue;
146 case 'B':
147 pt = _add((t->tm_mon < 0 ||
148 t->tm_mon >= MONSPERYEAR) ?
149 "?" : (Oalternative ? tptr->alt_month :
150 tptr->month)[t->tm_mon],
151 pt, ptlim);
152 continue;
153 case 'b':
154 case 'h':
155 pt = _add((t->tm_mon < 0 ||
156 t->tm_mon >= MONSPERYEAR) ?
157 "?" : tptr->mon[t->tm_mon],
158 pt, ptlim);
159 continue;
160 case 'C':
161 /*
162 * %C used to do a...
163 * _fmt("%a %b %e %X %Y", t);
164 * ...whereas now POSIX 1003.2 calls for
165 * something completely different.
166 * (ado, 1993-05-24)
167 */
168 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
169 pt, ptlim);
170 continue;
171 case 'c':
172 {
173 int warn2 = IN_SOME;
174
175 pt = _fmt(tptr->c_fmt, t, pt, ptlim, &warn2, loc);
176 if (warn2 == IN_ALL)
177 warn2 = IN_THIS;
178 if (warn2 > *warnp)
179 *warnp = warn2;
180 }
181 continue;
182 case 'D':
183 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp, loc);
184 continue;
185 case 'd':
186 pt = _conv(t->tm_mday, fmt_padding[PAD_FMT_DAYOFMONTH][PadIndex],
187 pt, ptlim);
188 continue;
189 case 'E':
190 if (Ealternative || Oalternative)
191 break;
192 Ealternative++;
193 goto label;
194 case 'O':
195 /*
196 * C99 locale modifiers.
197 * The sequences
198 * %Ec %EC %Ex %EX %Ey %EY
199 * %Od %oe %OH %OI %Om %OM
200 * %OS %Ou %OU %OV %Ow %OW %Oy
201 * are supposed to provide alternate
202 * representations.
203 *
204 * FreeBSD extension
205 * %OB
206 */
207 if (Ealternative || Oalternative)
208 break;
209 Oalternative++;
210 goto label;
211 case 'e':
212 pt = _conv(t->tm_mday,
213 fmt_padding[PAD_FMT_SDAYOFMONTH][PadIndex], pt, ptlim);
214 continue;
215 case 'F':
216 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp, loc);
217 continue;
218 case 'H':
219 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_HMS][PadIndex],
220 pt, ptlim);
221 continue;
222 case 'I':
223 pt = _conv((t->tm_hour % 12) ?
224 (t->tm_hour % 12) : 12,
225 fmt_padding[PAD_FMT_HMS][PadIndex], pt, ptlim);
226 continue;
227 case 'j':
228 pt = _conv(t->tm_yday + 1,
229 fmt_padding[PAD_FMT_DAYOFYEAR][PadIndex], pt, ptlim);
230 continue;
231 case 'k':
232 /*
233 * This used to be...
234 * _conv(t->tm_hour % 12 ?
235 * t->tm_hour % 12 : 12, 2, ' ');
236 * ...and has been changed to the below to
237 * match SunOS 4.1.1 and Arnold Robbins'
238 * strftime version 3.0. That is, "%k" and
239 * "%l" have been swapped.
240 * (ado, 1993-05-24)
241 */
242 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_SHMS][PadIndex],
243 pt, ptlim);
244 continue;
245 #ifdef KITCHEN_SINK
246 case 'K':
247 /*
248 * After all this time, still unclaimed!
249 */
250 pt = _add("kitchen sink", pt, ptlim);
251 continue;
252 #endif /* defined KITCHEN_SINK */
253 case 'l':
254 /*
255 * This used to be...
256 * _conv(t->tm_hour, 2, ' ');
257 * ...and has been changed to the below to
258 * match SunOS 4.1.1 and Arnold Robbin's
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 % 12) ?
264 (t->tm_hour % 12) : 12,
265 fmt_padding[PAD_FMT_SHMS][PadIndex], pt, ptlim);
266 continue;
267 case 'M':
268 pt = _conv(t->tm_min, fmt_padding[PAD_FMT_HMS][PadIndex],
269 pt, ptlim);
270 continue;
271 case 'm':
272 pt = _conv(t->tm_mon + 1,
273 fmt_padding[PAD_FMT_MONTH][PadIndex], pt, ptlim);
274 continue;
275 case 'n':
276 pt = _add("\n", pt, ptlim);
277 continue;
278 case 'p':
279 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
280 tptr->pm :
281 tptr->am,
282 pt, ptlim);
283 continue;
284 case 'R':
285 pt = _fmt("%H:%M", t, pt, ptlim, warnp, loc);
286 continue;
287 case 'r':
288 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim,
289 warnp, loc);
290 continue;
291 case 'S':
292 pt = _conv(t->tm_sec, fmt_padding[PAD_FMT_HMS][PadIndex],
293 pt, ptlim);
294 continue;
295 case 's':
296 {
297 struct tm tm;
298 char buf[INT_STRLEN_MAXIMUM(
299 time_t) + 1];
300 time_t mkt;
301
302 tm = *t;
303 mkt = mktime(&tm);
304 if (TYPE_SIGNED(time_t))
305 snprintf(buf, sizeof(buf),
306 "%"PRIdMAX,
307 (intmax_t) mkt);
308 else snprintf(buf, sizeof(buf),
309 "%"PRIuMAX,
310 (uintmax_t) mkt);
311 pt = _add(buf, pt, ptlim);
312 }
313 continue;
314 case 'T':
315 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp, loc);
316 continue;
317 case 't':
318 pt = _add("\t", pt, ptlim);
319 continue;
320 case 'U':
321 pt = _conv((t->tm_yday + DAYSPERWEEK -
322 t->tm_wday) / DAYSPERWEEK,
323 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim);
324 continue;
325 case 'u':
326 /*
327 * From Arnold Robbins' strftime version 3.0:
328 * "ISO 8601: Weekday as a decimal number
329 * [1 (Monday) - 7]"
330 * (ado, 1993-05-24)
331 */
332 pt = _conv((t->tm_wday == 0) ?
333 DAYSPERWEEK : t->tm_wday,
334 "%d", pt, ptlim);
335 continue;
336 case 'V': /* ISO 8601 week number */
337 case 'G': /* ISO 8601 year (four digits) */
338 case 'g': /* ISO 8601 year (two digits) */
339 /*
340 * From Arnold Robbins' strftime version 3.0: "the week number of the
341 * year (the first Monday as the first day of week 1) as a decimal number
342 * (01-53)."
343 * (ado, 1993-05-24)
344 *
345 * From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
346 * "Week 01 of a year is per definition the first week which has the
347 * Thursday in this year, which is equivalent to the week which contains
348 * the fourth day of January. In other words, the first week of a new year
349 * is the week which has the majority of its days in the new year. Week 01
350 * might also contain days from the previous year and the week before week
351 * 01 of a year is the last week (52 or 53) of the previous year even if
352 * it contains days from the new year. A week starts with Monday (day 1)
353 * and ends with Sunday (day 7). For example, the first week of the year
354 * 1997 lasts from 1996-12-30 to 1997-01-05..."
355 * (ado, 1996-01-02)
356 */
357 {
358 int year;
359 int base;
360 int yday;
361 int wday;
362 int w;
363
364 year = t->tm_year;
365 base = TM_YEAR_BASE;
366 yday = t->tm_yday;
367 wday = t->tm_wday;
368 for ( ; ; ) {
369 int len;
370 int bot;
371 int top;
372
373 len = isleap_sum(year, base) ?
374 DAYSPERLYEAR :
375 DAYSPERNYEAR;
376 /*
377 * What yday (-3 ... 3) does
378 * the ISO year begin on?
379 */
380 bot = ((yday + 11 - wday) %
381 DAYSPERWEEK) - 3;
382 /*
383 * What yday does the NEXT
384 * ISO year begin on?
385 */
386 top = bot -
387 (len % DAYSPERWEEK);
388 if (top < -3)
389 top += DAYSPERWEEK;
390 top += len;
391 if (yday >= top) {
392 ++base;
393 w = 1;
394 break;
395 }
396 if (yday >= bot) {
397 w = 1 + ((yday - bot) /
398 DAYSPERWEEK);
399 break;
400 }
401 --base;
402 yday += isleap_sum(year, base) ?
403 DAYSPERLYEAR :
404 DAYSPERNYEAR;
405 }
406 #ifdef XPG4_1994_04_09
407 if ((w == 52 &&
408 t->tm_mon == TM_JANUARY) ||
409 (w == 1 &&
410 t->tm_mon == TM_DECEMBER))
411 w = 53;
412 #endif /* defined XPG4_1994_04_09 */
413 if (*format == 'V')
414 pt = _conv(w, fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex],
415 pt, ptlim);
416 else if (*format == 'g') {
417 *warnp = IN_ALL;
418 pt = _yconv(year, base, 0, 1,
419 pt, ptlim);
420 } else pt = _yconv(year, base, 1, 1,
421 pt, ptlim);
422 }
423 continue;
424 case 'v':
425 /*
426 * From Arnold Robbins' strftime version 3.0:
427 * "date as dd-bbb-YYYY"
428 * (ado, 1993-05-24)
429 */
430 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp, loc);
431 continue;
432 case 'W':
433 pt = _conv((t->tm_yday + DAYSPERWEEK -
434 (t->tm_wday ?
435 (t->tm_wday - 1) :
436 (DAYSPERWEEK - 1))) / DAYSPERWEEK,
437 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim);
438 continue;
439 case 'w':
440 pt = _conv(t->tm_wday, "%d", pt, ptlim);
441 continue;
442 case 'X':
443 pt = _fmt(tptr->X_fmt, t, pt, ptlim, warnp, loc);
444 continue;
445 case 'x':
446 {
447 int warn2 = IN_SOME;
448
449 pt = _fmt(tptr->x_fmt, t, pt, ptlim, &warn2, loc);
450 if (warn2 == IN_ALL)
451 warn2 = IN_THIS;
452 if (warn2 > *warnp)
453 *warnp = warn2;
454 }
455 continue;
456 case 'y':
457 *warnp = IN_ALL;
458 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
459 pt, ptlim);
460 continue;
461 case 'Y':
462 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
463 pt, ptlim);
464 continue;
465 case 'Z':
466 if (t->TM_ZONE != NULL)
467 pt = _add(t->TM_ZONE, pt, ptlim);
468 else
469 if (t->tm_isdst >= 0)
470 pt = _add(tzname[t->tm_isdst != 0],
471 pt, ptlim);
472 /*
473 * C99 says that %Z must be replaced by the
474 * empty string if the time zone is not
475 * determinable.
476 */
477 continue;
478 case 'z':
479 {
480 long diff;
481 char const * sign;
482
483 if (t->tm_isdst < 0)
484 continue;
485 diff = t->TM_GMTOFF;
486 if (diff < 0) {
487 sign = "-";
488 diff = -diff;
489 } else
490 sign = "+";
491 pt = _add(sign, pt, ptlim);
492 diff /= SECSPERMIN;
493 diff = (diff / MINSPERHOUR) * 100 +
494 (diff % MINSPERHOUR);
495 pt = _conv(diff,
496 fmt_padding[PAD_FMT_YEAR][PadIndex], pt, ptlim);
497 }
498 continue;
499 case '+':
500 pt = _fmt(tptr->date_fmt, t, pt, ptlim,
501 warnp, loc);
502 continue;
503 case '-':
504 if (PadIndex != PAD_DEFAULT)
505 break;
506 PadIndex = PAD_LESS;
507 goto label;
508 case '_':
509 if (PadIndex != PAD_DEFAULT)
510 break;
511 PadIndex = PAD_SPACE;
512 goto label;
513 case '0':
514 if (PadIndex != PAD_DEFAULT)
515 break;
516 PadIndex = PAD_ZERO;
517 goto label;
518 case '%':
519 /*
520 * X311J/88-090 (4.12.3.5): if conversion char is
521 * undefined, behavior is undefined. Print out the
522 * character itself as printf(3) also does.
523 */
524 default:
525 break;
526 }
527 }
528 if (pt == ptlim)
529 break;
530 *pt++ = *format;
531 }
532 return pt;
533 }
534
535 static char *
_conv(const int n,const char * const format,char * const pt,const char * const ptlim)536 _conv(const int n, const char * const format, char * const pt,
537 const char * const ptlim)
538 {
539 char buf[INT_STRLEN_MAXIMUM(int) + 1];
540
541 snprintf(buf, sizeof(buf), format, n);
542 return _add(buf, pt, ptlim);
543 }
544
545 static char *
_add(const char * str,char * pt,const char * const ptlim)546 _add(const char *str, char *pt, const char * const ptlim)
547 {
548 while (pt < ptlim && (*pt = *str++) != '\0')
549 ++pt;
550 return pt;
551 }
552
553 /*
554 * POSIX and the C Standard are unclear or inconsistent about
555 * what %C and %y do if the year is negative or exceeds 9999.
556 * Use the convention that %C concatenated with %y yields the
557 * same output as %Y, and that %Y contains at least 4 bytes,
558 * with more only if necessary.
559 */
560
561 static char *
_yconv(const int a,const int b,const int convert_top,const int convert_yy,char * pt,const char * const ptlim)562 _yconv(const int a, const int b, const int convert_top, const int convert_yy,
563 char *pt, const char * const ptlim)
564 {
565 int lead;
566 int trail;
567
568 #define DIVISOR 100
569 trail = a % DIVISOR + b % DIVISOR;
570 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
571 trail %= DIVISOR;
572 if (trail < 0 && lead > 0) {
573 trail += DIVISOR;
574 --lead;
575 } else if (lead < 0 && trail > 0) {
576 trail -= DIVISOR;
577 ++lead;
578 }
579 if (convert_top) {
580 if (lead == 0 && trail < 0)
581 pt = _add("-0", pt, ptlim);
582 else pt = _conv(lead, "%02d", pt, ptlim);
583 }
584 if (convert_yy)
585 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
586 return pt;
587 }
588