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b168057a | 1 | /* Copyright (C) 1991-2015 Free Software Foundation, Inc. |
f65fd747 | 2 | This file is part of the GNU C Library. |
28f540f4 | 3 | |
f65fd747 | 4 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
28f540f4 | 8 | |
f65fd747 UD |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
28f540f4 | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
28f540f4 | 17 | |
28f540f4 | 18 | #include <ctype.h> |
9a0a462c UD |
19 | #include <errno.h> |
20 | #include <bits/libc-lock.h> | |
42261ad7 | 21 | #include <stdbool.h> |
28f540f4 RM |
22 | #include <stddef.h> |
23 | #include <stdio.h> | |
24 | #include <stdlib.h> | |
25 | #include <string.h> | |
26 | #include <time.h> | |
27 | ||
9a0a462c | 28 | |
28f540f4 | 29 | #define NOID |
14ea22e9 | 30 | #include <timezone/tzfile.h> |
28f540f4 | 31 | |
28f540f4 RM |
32 | char *__tzname[2] = { (char *) "GMT", (char *) "GMT" }; |
33 | int __daylight = 0; | |
34 | long int __timezone = 0L; | |
35 | ||
0ac2e7d8 BK |
36 | weak_alias (__tzname, tzname) |
37 | weak_alias (__daylight, daylight) | |
38 | weak_alias (__timezone, timezone) | |
39 | ||
9a0a462c | 40 | /* This locks all the state variables in tzfile.c and this file. */ |
727211c4 | 41 | __libc_lock_define_initialized (static, tzset_lock) |
9a0a462c | 42 | |
28f540f4 RM |
43 | |
44 | #define min(a, b) ((a) < (b) ? (a) : (b)) | |
45 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
46 | #define sign(x) ((x) < 0 ? -1 : 1) | |
47 | ||
48 | ||
49 | /* This structure contains all the information about a | |
50 | timezone given in the POSIX standard TZ envariable. */ | |
51 | typedef struct | |
52 | { | |
cd6ede75 | 53 | const char *name; |
28f540f4 RM |
54 | |
55 | /* When to change. */ | |
56 | enum { J0, J1, M } type; /* Interpretation of: */ | |
57 | unsigned short int m, n, d; /* Month, week, day. */ | |
0748546f | 58 | int secs; /* Time of day. */ |
28f540f4 RM |
59 | |
60 | long int offset; /* Seconds east of GMT (west if < 0). */ | |
61 | ||
62 | /* We cache the computed time of change for a | |
63 | given year so we don't have to recompute it. */ | |
64 | time_t change; /* When to change to this zone. */ | |
65 | int computed_for; /* Year above is computed for. */ | |
66 | } tz_rule; | |
67 | ||
68 | /* tz_rules[0] is standard, tz_rules[1] is daylight. */ | |
69 | static tz_rule tz_rules[2]; | |
f65fd747 UD |
70 | |
71 | ||
79937577 | 72 | static void compute_change (tz_rule *rule, int year) __THROW internal_function; |
79937577 UD |
73 | static void tzset_internal (int always, int explicit) |
74 | __THROW internal_function; | |
28f540f4 | 75 | \f |
2698e32c UD |
76 | /* List of buffers containing time zone strings. */ |
77 | struct tzstring_l | |
cd6ede75 | 78 | { |
2698e32c UD |
79 | struct tzstring_l *next; |
80 | size_t len; /* strlen(data) - doesn't count terminating NUL! */ | |
81 | char data[0]; | |
cd6ede75 UD |
82 | }; |
83 | ||
418f1701 | 84 | static struct tzstring_l *tzstring_list; |
cd6ede75 | 85 | |
42261ad7 FW |
86 | /* Allocate a permanent home for the first LEN characters of S. It |
87 | will never be moved or deallocated, but may share space with other | |
88 | strings. Don't modify the returned string. */ | |
89 | static char * | |
90 | __tzstring_len (const char *s, size_t len) | |
cd6ede75 | 91 | { |
cd6ede75 | 92 | char *p; |
2698e32c | 93 | struct tzstring_l *t, *u, *new; |
2698e32c UD |
94 | |
95 | /* Walk the list and look for a match. If this string is the same | |
96 | as the end of an already-allocated string, it can share space. */ | |
97 | for (u = t = tzstring_list; t; u = t, t = t->next) | |
98 | if (len <= t->len) | |
99 | { | |
100 | p = &t->data[t->len - len]; | |
42261ad7 | 101 | if (memcmp (s, p, len) == 0) |
cd6ede75 | 102 | return p; |
2698e32c UD |
103 | } |
104 | ||
105 | /* Not found; allocate a new buffer. */ | |
106 | new = malloc (sizeof (struct tzstring_l) + len + 1); | |
107 | if (!new) | |
108 | return NULL; | |
109 | ||
110 | new->next = NULL; | |
111 | new->len = len; | |
42261ad7 FW |
112 | memcpy (new->data, s, len); |
113 | new->data[len] = '\0'; | |
2698e32c UD |
114 | |
115 | if (u) | |
116 | u->next = new; | |
117 | else | |
118 | tzstring_list = new; | |
119 | ||
120 | return new->data; | |
cd6ede75 | 121 | } |
42261ad7 FW |
122 | |
123 | /* Allocate a permanent home for S. It will never be moved or | |
124 | deallocated, but may share space with other strings. Don't modify | |
125 | the returned string. */ | |
126 | char * | |
127 | __tzstring (const char *s) | |
128 | { | |
129 | return __tzstring_len (s, strlen (s)); | |
130 | } | |
cd6ede75 | 131 | \f |
a3931cbe UD |
132 | /* Maximum length of a timezone name. tzset_internal keeps this up to date |
133 | (never decreasing it) when ! __use_tzfile. | |
134 | tzfile.c keeps it up to date when __use_tzfile. */ | |
135 | size_t __tzname_cur_max; | |
136 | ||
137 | long int | |
60d2f8f3 | 138 | __tzname_max (void) |
a3931cbe UD |
139 | { |
140 | __libc_lock_lock (tzset_lock); | |
141 | ||
c3d1af70 | 142 | tzset_internal (0, 0); |
a3931cbe UD |
143 | |
144 | __libc_lock_unlock (tzset_lock); | |
145 | ||
146 | return __tzname_cur_max; | |
147 | } | |
148 | \f | |
c4563d2d | 149 | static char *old_tz; |
28f540f4 | 150 | |
9a0a462c | 151 | static void |
dfd2257a | 152 | internal_function |
fa76dde2 UD |
153 | update_vars (void) |
154 | { | |
155 | __daylight = tz_rules[0].offset != tz_rules[1].offset; | |
156 | __timezone = -tz_rules[0].offset; | |
157 | __tzname[0] = (char *) tz_rules[0].name; | |
158 | __tzname[1] = (char *) tz_rules[1].name; | |
159 | ||
160 | /* Keep __tzname_cur_max up to date. */ | |
161 | size_t len0 = strlen (__tzname[0]); | |
162 | size_t len1 = strlen (__tzname[1]); | |
163 | if (len0 > __tzname_cur_max) | |
164 | __tzname_cur_max = len0; | |
165 | if (len1 > __tzname_cur_max) | |
166 | __tzname_cur_max = len1; | |
167 | } | |
168 | ||
bd82a247 UD |
169 | |
170 | static unsigned int | |
171 | __attribute_noinline__ | |
172 | compute_offset (unsigned int ss, unsigned int mm, unsigned int hh) | |
173 | { | |
174 | return min (ss, 59) + min (mm, 59) * 60 + min (hh, 24) * 60 * 60; | |
175 | } | |
176 | ||
42261ad7 FW |
177 | /* Parses the time zone name at *TZP, and writes a pointer to an |
178 | interned string to tz_rules[WHICHRULE].name. On success, advances | |
179 | *TZP, and returns true. Returns false otherwise. */ | |
180 | static bool | |
181 | parse_tzname (const char **tzp, int whichrule) | |
28f540f4 | 182 | { |
42261ad7 FW |
183 | const char *start = *tzp; |
184 | const char *p = start; | |
185 | while (('a' <= *p && *p <= 'z') | |
186 | || ('A' <= *p && *p <= 'Z')) | |
187 | ++p; | |
188 | size_t len = p - start; | |
189 | if (len < 3) | |
82780cbe | 190 | { |
42261ad7 FW |
191 | p = *tzp; |
192 | if (__glibc_unlikely (*p++ != '<')) | |
193 | return false; | |
194 | start = p; | |
195 | while (('a' <= *p && *p <= 'z') | |
196 | || ('A' <= *p && *p <= 'Z') | |
197 | || ('0' <= *p && *p <= '9') | |
198 | || *p == '+' || *p == '-') | |
199 | ++p; | |
200 | len = p - start; | |
201 | if (*p++ != '>' || len < 3) | |
202 | return false; | |
82780cbe | 203 | } |
cc8dcf96 FW |
204 | |
205 | const char *name = __tzstring_len (start, len); | |
206 | if (name == NULL) | |
207 | return false; | |
208 | tz_rules[whichrule].name = name; | |
209 | ||
42261ad7 FW |
210 | *tzp = p; |
211 | return true; | |
212 | } | |
28f540f4 | 213 | |
42261ad7 FW |
214 | /* Parses the time zone offset at *TZP, and writes it to |
215 | tz_rules[WHICHRULE].offset. Returns true if the parse was | |
216 | successful. */ | |
217 | static bool | |
218 | parse_offset (const char **tzp, int whichrule) | |
219 | { | |
220 | const char *tz = *tzp; | |
221 | if (whichrule == 0 | |
222 | && (*tz == '\0' || (*tz != '+' && *tz != '-' && !isdigit (*tz)))) | |
223 | return false; | |
28f540f4 | 224 | |
42261ad7 | 225 | long sign; |
28f540f4 | 226 | if (*tz == '-' || *tz == '+') |
42261ad7 | 227 | sign = *tz++ == '-' ? 1L : -1L; |
28f540f4 | 228 | else |
42261ad7 FW |
229 | sign = -1L; |
230 | *tzp = tz; | |
231 | ||
232 | unsigned short int hh; | |
233 | unsigned short mm = 0; | |
234 | unsigned short ss = 0; | |
235 | int consumed = 0; | |
236 | if (sscanf (tz, "%hu%n:%hu%n:%hu%n", | |
237 | &hh, &consumed, &mm, &consumed, &ss, &consumed) > 0) | |
238 | tz_rules[whichrule].offset = sign * compute_offset (ss, mm, hh); | |
239 | else | |
240 | /* Nothing could be parsed. */ | |
241 | if (whichrule == 0) | |
242 | { | |
243 | /* Standard time defaults to offset zero. */ | |
244 | tz_rules[0].offset = 0; | |
245 | return false; | |
246 | } | |
82780cbe | 247 | else |
42261ad7 FW |
248 | /* DST defaults to one hour later than standard time. */ |
249 | tz_rules[1].offset = tz_rules[0].offset + (60 * 60); | |
250 | *tzp = tz + consumed; | |
251 | return true; | |
252 | } | |
cd6ede75 | 253 | |
42261ad7 FW |
254 | /* Parses the standard <-> DST rules at *TZP. Updates |
255 | tz_rule[WHICHRULE]. On success, advances *TZP and returns true. | |
256 | Otherwise, returns false. */ | |
257 | static bool | |
258 | parse_rule (const char **tzp, int whichrule) | |
259 | { | |
260 | const char *tz = *tzp; | |
261 | tz_rule *tzr = &tz_rules[whichrule]; | |
fd26970f | 262 | |
42261ad7 FW |
263 | /* Ignore comma to support string following the incorrect |
264 | specification in early POSIX.1 printings. */ | |
265 | tz += *tz == ','; | |
fd26970f | 266 | |
42261ad7 FW |
267 | /* Get the date of the change. */ |
268 | if (*tz == 'J' || isdigit (*tz)) | |
269 | { | |
270 | char *end; | |
271 | tzr->type = *tz == 'J' ? J1 : J0; | |
272 | if (tzr->type == J1 && !isdigit (*++tz)) | |
273 | return false; | |
274 | unsigned long int d = strtoul (tz, &end, 10); | |
275 | if (end == tz || d > 365) | |
276 | return false; | |
277 | if (tzr->type == J1 && d == 0) | |
278 | return false; | |
279 | tzr->d = d; | |
280 | tz = end; | |
281 | } | |
282 | else if (*tz == 'M') | |
283 | { | |
284 | tzr->type = M; | |
285 | int consumed; | |
286 | if (sscanf (tz, "M%hu.%hu.%hu%n", | |
287 | &tzr->m, &tzr->n, &tzr->d, &consumed) != 3 | |
288 | || tzr->m < 1 || tzr->m > 12 | |
289 | || tzr->n < 1 || tzr->n > 5 || tzr->d > 6) | |
290 | return false; | |
291 | tz += consumed; | |
292 | } | |
293 | else if (*tz == '\0') | |
294 | { | |
295 | /* Daylight time rules in the U.S. are defined in the U.S. Code, | |
296 | Title 15, Chapter 6, Subchapter IX - Standard Time. These | |
297 | dates were established by Congress in the Energy Policy Act | |
298 | of 2005 [Pub. L. no. 109-58, 119 Stat 594 (2005)]. | |
299 | Below is the equivalent of "M3.2.0,M11.1.0" [/2 not needed | |
300 | since 2:00AM is the default]. */ | |
301 | tzr->type = M; | |
302 | if (tzr == &tz_rules[0]) | |
fd26970f | 303 | { |
42261ad7 FW |
304 | tzr->m = 3; |
305 | tzr->n = 2; | |
306 | tzr->d = 0; | |
fd26970f | 307 | } |
42261ad7 | 308 | else |
0413b54c | 309 | { |
42261ad7 FW |
310 | tzr->m = 11; |
311 | tzr->n = 1; | |
312 | tzr->d = 0; | |
0413b54c | 313 | } |
28f540f4 | 314 | } |
5290baf0 | 315 | else |
42261ad7 FW |
316 | return false; |
317 | ||
318 | if (*tz != '\0' && *tz != '/' && *tz != ',') | |
319 | return false; | |
320 | else if (*tz == '/') | |
40a55d20 | 321 | { |
42261ad7 FW |
322 | /* Get the time of day of the change. */ |
323 | int negative; | |
324 | ++tz; | |
325 | if (*tz == '\0') | |
326 | return false; | |
327 | negative = *tz == '-'; | |
328 | tz += negative; | |
329 | /* Default to 2:00 AM. */ | |
330 | unsigned short hh = 2; | |
331 | unsigned short mm = 0; | |
332 | unsigned short ss = 0; | |
333 | int consumed = 0; | |
334 | sscanf (tz, "%hu%n:%hu%n:%hu%n", | |
335 | &hh, &consumed, &mm, &consumed, &ss, &consumed);; | |
336 | tz += consumed; | |
337 | tzr->secs = (negative ? -1 : 1) * ((hh * 60 * 60) + (mm * 60) + ss); | |
40a55d20 | 338 | } |
42261ad7 FW |
339 | else |
340 | /* Default to 2:00 AM. */ | |
341 | tzr->secs = 2 * 60 * 60; | |
28f540f4 | 342 | |
42261ad7 FW |
343 | tzr->computed_for = -1; |
344 | *tzp = tz; | |
345 | return true; | |
346 | } | |
1cbca0d9 | 347 | |
42261ad7 FW |
348 | /* Parse the POSIX TZ-style string. */ |
349 | void | |
350 | __tzset_parse_tz (const char *tz) | |
351 | { | |
352 | /* Clear out old state and reset to unnamed UTC. */ | |
353 | memset (tz_rules, '\0', sizeof tz_rules); | |
354 | tz_rules[0].name = tz_rules[1].name = ""; | |
1cbca0d9 | 355 | |
42261ad7 FW |
356 | /* Get the standard timezone name. */ |
357 | if (parse_tzname (&tz, 0) && parse_offset (&tz, 0)) | |
358 | { | |
359 | /* Get the DST timezone name (if any). */ | |
360 | if (*tz != '\0') | |
28f540f4 | 361 | { |
42261ad7 | 362 | if (parse_tzname (&tz, 1)) |
28f540f4 | 363 | { |
42261ad7 FW |
364 | parse_offset (&tz, 1); |
365 | if (*tz == '\0' || (tz[0] == ',' && tz[1] == '\0')) | |
366 | { | |
367 | /* There is no rule. See if there is a default rule | |
368 | file. */ | |
369 | __tzfile_default (tz_rules[0].name, tz_rules[1].name, | |
370 | tz_rules[0].offset, tz_rules[1].offset); | |
371 | if (__use_tzfile) | |
372 | { | |
373 | free (old_tz); | |
374 | old_tz = NULL; | |
375 | return; | |
376 | } | |
377 | } | |
28f540f4 | 378 | } |
42261ad7 FW |
379 | /* Figure out the standard <-> DST rules. */ |
380 | if (parse_rule (&tz, 0)) | |
381 | parse_rule (&tz, 1); | |
28f540f4 RM |
382 | } |
383 | else | |
28f540f4 | 384 | { |
42261ad7 FW |
385 | /* There is no DST. */ |
386 | tz_rules[1].name = tz_rules[0].name; | |
387 | tz_rules[1].offset = tz_rules[0].offset; | |
28f540f4 | 388 | } |
28f540f4 | 389 | } |
90865aa8 | 390 | |
fa76dde2 UD |
391 | update_vars (); |
392 | } | |
28f540f4 | 393 | |
fa76dde2 UD |
394 | /* Interpret the TZ envariable. */ |
395 | static void | |
396 | internal_function | |
397 | tzset_internal (always, explicit) | |
398 | int always; | |
399 | int explicit; | |
400 | { | |
401 | static int is_initialized; | |
2e09a79a | 402 | const char *tz; |
fa76dde2 UD |
403 | |
404 | if (is_initialized && !always) | |
405 | return; | |
406 | is_initialized = 1; | |
407 | ||
408 | /* Examine the TZ environment variable. */ | |
409 | tz = getenv ("TZ"); | |
410 | if (tz == NULL && !explicit) | |
411 | /* Use the site-wide default. This is a file name which means we | |
412 | would not see changes to the file if we compare only the file | |
413 | name for change. We want to notice file changes if tzset() has | |
414 | been called explicitly. Leave TZ as NULL in this case. */ | |
415 | tz = TZDEFAULT; | |
416 | if (tz && *tz == '\0') | |
417 | /* User specified the empty string; use UTC explicitly. */ | |
418 | tz = "Universal"; | |
419 | ||
420 | /* A leading colon means "implementation defined syntax". | |
421 | We ignore the colon and always use the same algorithm: | |
422 | try a data file, and if none exists parse the 1003.1 syntax. */ | |
423 | if (tz && *tz == ':') | |
424 | ++tz; | |
425 | ||
58423c7d | 426 | /* Check whether the value changed since the last run. */ |
fa76dde2 UD |
427 | if (old_tz != NULL && tz != NULL && strcmp (tz, old_tz) == 0) |
428 | /* No change, simply return. */ | |
429 | return; | |
430 | ||
431 | if (tz == NULL) | |
432 | /* No user specification; use the site-wide default. */ | |
433 | tz = TZDEFAULT; | |
434 | ||
435 | tz_rules[0].name = NULL; | |
436 | tz_rules[1].name = NULL; | |
437 | ||
438 | /* Save the value of `tz'. */ | |
72e6cdfa | 439 | free (old_tz); |
fa76dde2 UD |
440 | old_tz = tz ? __strdup (tz) : NULL; |
441 | ||
442 | /* Try to read a data file. */ | |
443 | __tzfile_read (tz, 0, NULL); | |
444 | if (__use_tzfile) | |
445 | return; | |
446 | ||
447 | /* No data file found. Default to UTC if nothing specified. */ | |
448 | ||
449 | if (tz == NULL || *tz == '\0' | |
450 | || (TZDEFAULT != NULL && strcmp (tz, TZDEFAULT) == 0)) | |
451 | { | |
bd82a247 | 452 | memset (tz_rules, '\0', sizeof tz_rules); |
fa76dde2 | 453 | tz_rules[0].name = tz_rules[1].name = "UTC"; |
bd82a247 UD |
454 | if (J0 != 0) |
455 | tz_rules[0].type = tz_rules[1].type = J0; | |
fa76dde2 | 456 | tz_rules[0].change = tz_rules[1].change = (time_t) -1; |
fa76dde2 UD |
457 | update_vars (); |
458 | return; | |
459 | } | |
460 | ||
461 | __tzset_parse_tz (tz); | |
28f540f4 RM |
462 | } |
463 | \f | |
464 | /* Figure out the exact time (as a time_t) in YEAR | |
465 | when the change described by RULE will occur and | |
a3931cbe UD |
466 | put it in RULE->change, saving YEAR in RULE->computed_for. */ |
467 | static void | |
dfd2257a | 468 | internal_function |
f65fd747 UD |
469 | compute_change (rule, year) |
470 | tz_rule *rule; | |
471 | int year; | |
28f540f4 | 472 | { |
2e09a79a | 473 | time_t t; |
28f540f4 RM |
474 | |
475 | if (year != -1 && rule->computed_for == year) | |
7fcc87f4 | 476 | /* Operations on times in 2 BC will be slower. Oh well. */ |
a3931cbe | 477 | return; |
1cbca0d9 | 478 | |
28f540f4 | 479 | /* First set T to January 1st, 0:00:00 GMT in YEAR. */ |
7fcc87f4 UD |
480 | if (year > 1970) |
481 | t = ((year - 1970) * 365 | |
482 | + /* Compute the number of leapdays between 1970 and YEAR | |
483 | (exclusive). There is a leapday every 4th year ... */ | |
484 | + ((year - 1) / 4 - 1970 / 4) | |
485 | /* ... except every 100th year ... */ | |
486 | - ((year - 1) / 100 - 1970 / 100) | |
487 | /* ... but still every 400th year. */ | |
488 | + ((year - 1) / 400 - 1970 / 400)) * SECSPERDAY; | |
489 | else | |
490 | t = 0; | |
28f540f4 RM |
491 | |
492 | switch (rule->type) | |
493 | { | |
494 | case J1: | |
495 | /* Jn - Julian day, 1 == January 1, 60 == March 1 even in leap years. | |
496 | In non-leap years, or if the day number is 59 or less, just | |
497 | add SECSPERDAY times the day number-1 to the time of | |
498 | January 1, midnight, to get the day. */ | |
499 | t += (rule->d - 1) * SECSPERDAY; | |
500 | if (rule->d >= 60 && __isleap (year)) | |
501 | t += SECSPERDAY; | |
502 | break; | |
503 | ||
504 | case J0: | |
505 | /* n - Day of year. | |
506 | Just add SECSPERDAY times the day number to the time of Jan 1st. */ | |
507 | t += rule->d * SECSPERDAY; | |
508 | break; | |
509 | ||
510 | case M: | |
511 | /* Mm.n.d - Nth "Dth day" of month M. */ | |
512 | { | |
9a0a462c UD |
513 | unsigned int i; |
514 | int d, m1, yy0, yy1, yy2, dow; | |
515 | const unsigned short int *myday = | |
80fd7387 | 516 | &__mon_yday[__isleap (year)][rule->m]; |
28f540f4 RM |
517 | |
518 | /* First add SECSPERDAY for each day in months before M. */ | |
80fd7387 | 519 | t += myday[-1] * SECSPERDAY; |
28f540f4 RM |
520 | |
521 | /* Use Zeller's Congruence to get day-of-week of first day of month. */ | |
522 | m1 = (rule->m + 9) % 12 + 1; | |
523 | yy0 = (rule->m <= 2) ? (year - 1) : year; | |
524 | yy1 = yy0 / 100; | |
525 | yy2 = yy0 % 100; | |
526 | dow = ((26 * m1 - 2) / 10 + 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7; | |
527 | if (dow < 0) | |
528 | dow += 7; | |
529 | ||
530 | /* DOW is the day-of-week of the first day of the month. Get the | |
531 | day-of-month (zero-origin) of the first DOW day of the month. */ | |
532 | d = rule->d - dow; | |
533 | if (d < 0) | |
534 | d += 7; | |
535 | for (i = 1; i < rule->n; ++i) | |
536 | { | |
9a0a462c | 537 | if (d + 7 >= (int) myday[0] - myday[-1]) |
28f540f4 RM |
538 | break; |
539 | d += 7; | |
540 | } | |
541 | ||
542 | /* D is the day-of-month (zero-origin) of the day we want. */ | |
543 | t += d * SECSPERDAY; | |
544 | } | |
545 | break; | |
546 | } | |
547 | ||
548 | /* T is now the Epoch-relative time of 0:00:00 GMT on the day we want. | |
549 | Just add the time of day and local offset from GMT, and we're done. */ | |
550 | ||
68dbb3a6 | 551 | rule->change = t - rule->offset + rule->secs; |
28f540f4 | 552 | rule->computed_for = year; |
28f540f4 RM |
553 | } |
554 | ||
555 | ||
e3e35cfc | 556 | /* Figure out the correct timezone for TM and set `__tzname', |
a3931cbe | 557 | `__timezone', and `__daylight' accordingly. */ |
fa76dde2 | 558 | void |
dfd2257a | 559 | internal_function |
fa76dde2 UD |
560 | __tz_compute (timer, tm, use_localtime) |
561 | time_t timer; | |
562 | struct tm *tm; | |
563 | int use_localtime; | |
28f540f4 | 564 | { |
a3931cbe UD |
565 | compute_change (&tz_rules[0], 1900 + tm->tm_year); |
566 | compute_change (&tz_rules[1], 1900 + tm->tm_year); | |
fa76dde2 UD |
567 | |
568 | if (use_localtime) | |
569 | { | |
570 | int isdst; | |
571 | ||
572 | /* We have to distinguish between northern and southern | |
573 | hemisphere. For the latter the daylight saving time | |
574 | ends in the next year. */ | |
575 | if (__builtin_expect (tz_rules[0].change | |
576 | > tz_rules[1].change, 0)) | |
577 | isdst = (timer < tz_rules[1].change | |
578 | || timer >= tz_rules[0].change); | |
579 | else | |
580 | isdst = (timer >= tz_rules[0].change | |
581 | && timer < tz_rules[1].change); | |
582 | tm->tm_isdst = isdst; | |
583 | tm->tm_zone = __tzname[isdst]; | |
584 | tm->tm_gmtoff = tz_rules[isdst].offset; | |
585 | } | |
28f540f4 | 586 | } |
b24be05f | 587 | \f |
b24be05f | 588 | /* Reinterpret the TZ environment variable and set `tzname'. */ |
4311b2a6 | 589 | #undef tzset |
28f540f4 | 590 | |
b24be05f | 591 | void |
10dc2a90 | 592 | __tzset (void) |
b24be05f | 593 | { |
9a0a462c | 594 | __libc_lock_lock (tzset_lock); |
68dbb3a6 | 595 | |
c3d1af70 | 596 | tzset_internal (1, 1); |
68dbb3a6 | 597 | |
860d3729 UD |
598 | if (!__use_tzfile) |
599 | { | |
600 | /* Set `tzname'. */ | |
601 | __tzname[0] = (char *) tz_rules[0].name; | |
602 | __tzname[1] = (char *) tz_rules[1].name; | |
603 | } | |
68dbb3a6 | 604 | |
9a0a462c | 605 | __libc_lock_unlock (tzset_lock); |
b24be05f | 606 | } |
10dc2a90 | 607 | weak_alias (__tzset, tzset) |
9a0a462c UD |
608 | \f |
609 | /* Return the `struct tm' representation of *TIMER in the local timezone. | |
610 | Use local time if USE_LOCALTIME is nonzero, UTC otherwise. */ | |
611 | struct tm * | |
612 | __tz_convert (const time_t *timer, int use_localtime, struct tm *tp) | |
613 | { | |
614 | long int leap_correction; | |
615 | int leap_extra_secs; | |
616 | ||
617 | if (timer == NULL) | |
618 | { | |
619 | __set_errno (EINVAL); | |
620 | return NULL; | |
621 | } | |
622 | ||
623 | __libc_lock_lock (tzset_lock); | |
624 | ||
625 | /* Update internal database according to current TZ setting. | |
626 | POSIX.1 8.3.7.2 says that localtime_r is not required to set tzname. | |
58423c7d UD |
627 | This is a good idea since this allows at least a bit more parallelism. */ |
628 | tzset_internal (tp == &_tmbuf && use_localtime, 1); | |
9a0a462c UD |
629 | |
630 | if (__use_tzfile) | |
38e68573 UD |
631 | __tzfile_compute (*timer, use_localtime, &leap_correction, |
632 | &leap_extra_secs, tp); | |
9a0a462c UD |
633 | else |
634 | { | |
a3931cbe | 635 | if (! __offtime (timer, 0, tp)) |
9a0a462c | 636 | tp = NULL; |
a3931cbe | 637 | else |
fa76dde2 | 638 | __tz_compute (*timer, tp, use_localtime); |
9a0a462c UD |
639 | leap_correction = 0L; |
640 | leap_extra_secs = 0; | |
641 | } | |
642 | ||
6807b1db KE |
643 | __libc_lock_unlock (tzset_lock); |
644 | ||
9a0a462c UD |
645 | if (tp) |
646 | { | |
fa76dde2 | 647 | if (! use_localtime) |
9a0a462c UD |
648 | { |
649 | tp->tm_isdst = 0; | |
650 | tp->tm_zone = "GMT"; | |
651 | tp->tm_gmtoff = 0L; | |
652 | } | |
653 | ||
fe0ec73e UD |
654 | if (__offtime (timer, tp->tm_gmtoff - leap_correction, tp)) |
655 | tp->tm_sec += leap_extra_secs; | |
656 | else | |
657 | tp = NULL; | |
9a0a462c UD |
658 | } |
659 | ||
9a0a462c UD |
660 | return tp; |
661 | } | |
83628d31 UD |
662 | |
663 | ||
c877418f | 664 | libc_freeres_fn (free_mem) |
83628d31 UD |
665 | { |
666 | while (tzstring_list != NULL) | |
667 | { | |
668 | struct tzstring_l *old = tzstring_list; | |
669 | ||
670 | tzstring_list = tzstring_list->next; | |
671 | free (old); | |
672 | } | |
673 | free (old_tz); | |
674 | old_tz = NULL; | |
675 | } |