1 | /* Copyright (C) 1991-2017 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
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. |
8 | |
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 |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ |
17 | |
18 | #include <assert.h> |
19 | #include <limits.h> |
20 | #include <stdio.h> |
21 | #include <stdio_ext.h> |
22 | #include <stdlib.h> |
23 | #include <string.h> |
24 | #include <time.h> |
25 | #include <unistd.h> |
26 | #include <sys/stat.h> |
27 | #include <stdint.h> |
28 | |
29 | #define NOID |
30 | #include <timezone/tzfile.h> |
31 | |
32 | int __use_tzfile; |
33 | static dev_t tzfile_dev; |
34 | static ino64_t tzfile_ino; |
35 | static time_t tzfile_mtime; |
36 | |
37 | struct ttinfo |
38 | { |
39 | long int offset; /* Seconds east of GMT. */ |
40 | unsigned char isdst; /* Used to set tm_isdst. */ |
41 | unsigned char idx; /* Index into `zone_names'. */ |
42 | unsigned char isstd; /* Transition times are in standard time. */ |
43 | unsigned char isgmt; /* Transition times are in GMT. */ |
44 | }; |
45 | |
46 | struct leap |
47 | { |
48 | time_t transition; /* Time the transition takes effect. */ |
49 | long int change; /* Seconds of correction to apply. */ |
50 | }; |
51 | |
52 | static void compute_tzname_max (size_t) internal_function; |
53 | |
54 | static size_t num_transitions; |
55 | libc_freeres_ptr (static time_t *transitions); |
56 | static unsigned char *type_idxs; |
57 | static size_t num_types; |
58 | static struct ttinfo *types; |
59 | static char *zone_names; |
60 | static long int rule_stdoff; |
61 | static long int rule_dstoff; |
62 | static size_t num_leaps; |
63 | static struct leap *leaps; |
64 | static char *tzspec; |
65 | |
66 | #include <endian.h> |
67 | #include <byteswap.h> |
68 | |
69 | /* Decode the four bytes at PTR as a signed integer in network byte order. */ |
70 | static inline int |
71 | __attribute ((always_inline)) |
72 | decode (const void *ptr) |
73 | { |
74 | if (BYTE_ORDER == BIG_ENDIAN && sizeof (int) == 4) |
75 | return *(const int *) ptr; |
76 | if (sizeof (int) == 4) |
77 | return bswap_32 (*(const int *) ptr); |
78 | |
79 | const unsigned char *p = ptr; |
80 | int result = *p & (1 << (CHAR_BIT - 1)) ? ~0 : 0; |
81 | |
82 | result = (result << 8) | *p++; |
83 | result = (result << 8) | *p++; |
84 | result = (result << 8) | *p++; |
85 | result = (result << 8) | *p++; |
86 | |
87 | return result; |
88 | } |
89 | |
90 | |
91 | static inline int64_t |
92 | __attribute ((always_inline)) |
93 | decode64 (const void *ptr) |
94 | { |
95 | if ((BYTE_ORDER == BIG_ENDIAN)) |
96 | return *(const int64_t *) ptr; |
97 | |
98 | return bswap_64 (*(const int64_t *) ptr); |
99 | } |
100 | |
101 | |
102 | void |
103 | __tzfile_read (const char *file, size_t , char **) |
104 | { |
105 | static const char default_tzdir[] = TZDIR; |
106 | size_t num_isstd, num_isgmt; |
107 | FILE *f; |
108 | struct tzhead tzhead; |
109 | size_t chars; |
110 | size_t i; |
111 | size_t total_size; |
112 | size_t types_idx; |
113 | size_t leaps_idx; |
114 | int was_using_tzfile = __use_tzfile; |
115 | int trans_width = 4; |
116 | size_t tzspec_len; |
117 | char *new = NULL; |
118 | |
119 | if (sizeof (time_t) != 4 && sizeof (time_t) != 8) |
120 | abort (); |
121 | |
122 | __use_tzfile = 0; |
123 | |
124 | if (file == NULL) |
125 | /* No user specification; use the site-wide default. */ |
126 | file = TZDEFAULT; |
127 | else if (*file == '\0') |
128 | /* User specified the empty string; use UTC with no leap seconds. */ |
129 | goto ret_free_transitions; |
130 | else |
131 | { |
132 | /* We must not allow to read an arbitrary file in a setuid |
133 | program. So we fail for any file which is not in the |
134 | directory hierachy starting at TZDIR |
135 | and which is not the system wide default TZDEFAULT. */ |
136 | if (__libc_enable_secure |
137 | && ((*file == '/' |
138 | && memcmp (file, TZDEFAULT, sizeof TZDEFAULT) |
139 | && memcmp (file, default_tzdir, sizeof (default_tzdir) - 1)) |
140 | || strstr (file, "../" ) != NULL)) |
141 | /* This test is certainly a bit too restrictive but it should |
142 | catch all critical cases. */ |
143 | goto ret_free_transitions; |
144 | } |
145 | |
146 | if (*file != '/') |
147 | { |
148 | const char *tzdir; |
149 | |
150 | tzdir = getenv ("TZDIR" ); |
151 | if (tzdir == NULL || *tzdir == '\0') |
152 | tzdir = default_tzdir; |
153 | if (__asprintf (&new, "%s/%s" , tzdir, file) == -1) |
154 | goto ret_free_transitions; |
155 | file = new; |
156 | } |
157 | |
158 | /* If we were already using tzfile, check whether the file changed. */ |
159 | struct stat64 st; |
160 | if (was_using_tzfile |
161 | && stat64 (file, &st) == 0 |
162 | && tzfile_ino == st.st_ino && tzfile_dev == st.st_dev |
163 | && tzfile_mtime == st.st_mtime) |
164 | goto done; /* Nothing to do. */ |
165 | |
166 | /* Note the file is opened with cancellation in the I/O functions |
167 | disabled and if available FD_CLOEXEC set. */ |
168 | f = fopen (file, "rce" ); |
169 | if (f == NULL) |
170 | goto ret_free_transitions; |
171 | |
172 | /* Get information about the file we are actually using. */ |
173 | if (fstat64 (__fileno (f), &st) != 0) |
174 | { |
175 | fclose (f); |
176 | goto ret_free_transitions; |
177 | } |
178 | |
179 | free ((void *) transitions); |
180 | transitions = NULL; |
181 | |
182 | /* Remember the inode and device number and modification time. */ |
183 | tzfile_dev = st.st_dev; |
184 | tzfile_ino = st.st_ino; |
185 | tzfile_mtime = st.st_mtime; |
186 | |
187 | /* No threads reading this stream. */ |
188 | __fsetlocking (f, FSETLOCKING_BYCALLER); |
189 | |
190 | read_again: |
191 | if (__builtin_expect (__fread_unlocked ((void *) &tzhead, sizeof (tzhead), |
192 | 1, f) != 1, 0) |
193 | || memcmp (tzhead.tzh_magic, TZ_MAGIC, sizeof (tzhead.tzh_magic)) != 0) |
194 | goto lose; |
195 | |
196 | num_transitions = (size_t) decode (tzhead.tzh_timecnt); |
197 | num_types = (size_t) decode (tzhead.tzh_typecnt); |
198 | chars = (size_t) decode (tzhead.tzh_charcnt); |
199 | num_leaps = (size_t) decode (tzhead.tzh_leapcnt); |
200 | num_isstd = (size_t) decode (tzhead.tzh_ttisstdcnt); |
201 | num_isgmt = (size_t) decode (tzhead.tzh_ttisgmtcnt); |
202 | |
203 | if (__glibc_unlikely (num_isstd > num_types || num_isgmt > num_types)) |
204 | goto lose; |
205 | |
206 | /* For platforms with 64-bit time_t we use the new format if available. */ |
207 | if (sizeof (time_t) == 8 && trans_width == 4 |
208 | && tzhead.tzh_version[0] != '\0') |
209 | { |
210 | /* We use the 8-byte format. */ |
211 | trans_width = 8; |
212 | |
213 | /* Position the stream before the second header. */ |
214 | size_t to_skip = (num_transitions * (4 + 1) |
215 | + num_types * 6 |
216 | + chars |
217 | + num_leaps * 8 |
218 | + num_isstd |
219 | + num_isgmt); |
220 | if (fseek (f, to_skip, SEEK_CUR) != 0) |
221 | goto lose; |
222 | |
223 | goto read_again; |
224 | } |
225 | |
226 | if (__builtin_expect (num_transitions |
227 | > ((SIZE_MAX - (__alignof__ (struct ttinfo) - 1)) |
228 | / (sizeof (time_t) + 1)), 0)) |
229 | goto lose; |
230 | total_size = num_transitions * (sizeof (time_t) + 1); |
231 | total_size = ((total_size + __alignof__ (struct ttinfo) - 1) |
232 | & ~(__alignof__ (struct ttinfo) - 1)); |
233 | types_idx = total_size; |
234 | if (__builtin_expect (num_types |
235 | > (SIZE_MAX - total_size) / sizeof (struct ttinfo), 0)) |
236 | goto lose; |
237 | total_size += num_types * sizeof (struct ttinfo); |
238 | if (__glibc_unlikely (chars > SIZE_MAX - total_size)) |
239 | goto lose; |
240 | total_size += chars; |
241 | if (__builtin_expect (__alignof__ (struct leap) - 1 |
242 | > SIZE_MAX - total_size, 0)) |
243 | goto lose; |
244 | total_size = ((total_size + __alignof__ (struct leap) - 1) |
245 | & ~(__alignof__ (struct leap) - 1)); |
246 | leaps_idx = total_size; |
247 | if (__builtin_expect (num_leaps |
248 | > (SIZE_MAX - total_size) / sizeof (struct leap), 0)) |
249 | goto lose; |
250 | total_size += num_leaps * sizeof (struct leap); |
251 | tzspec_len = 0; |
252 | if (sizeof (time_t) == 8 && trans_width == 8) |
253 | { |
254 | off_t rem = st.st_size - __ftello (f); |
255 | if (__builtin_expect (rem < 0 |
256 | || (size_t) rem < (num_transitions * (8 + 1) |
257 | + num_types * 6 |
258 | + chars), 0)) |
259 | goto lose; |
260 | tzspec_len = (size_t) rem - (num_transitions * (8 + 1) |
261 | + num_types * 6 |
262 | + chars); |
263 | if (__builtin_expect (num_leaps > SIZE_MAX / 12 |
264 | || tzspec_len < num_leaps * 12, 0)) |
265 | goto lose; |
266 | tzspec_len -= num_leaps * 12; |
267 | if (__glibc_unlikely (tzspec_len < num_isstd)) |
268 | goto lose; |
269 | tzspec_len -= num_isstd; |
270 | if (__glibc_unlikely (tzspec_len == 0 || tzspec_len - 1 < num_isgmt)) |
271 | goto lose; |
272 | tzspec_len -= num_isgmt + 1; |
273 | if (__glibc_unlikely (tzspec_len == 0 |
274 | || SIZE_MAX - total_size < tzspec_len)) |
275 | goto lose; |
276 | } |
277 | if (__glibc_unlikely (SIZE_MAX - total_size - tzspec_len < extra)) |
278 | goto lose; |
279 | |
280 | /* Allocate enough memory including the extra block requested by the |
281 | caller. */ |
282 | transitions = (time_t *) malloc (total_size + tzspec_len + extra); |
283 | if (transitions == NULL) |
284 | goto lose; |
285 | |
286 | type_idxs = (unsigned char *) transitions + (num_transitions |
287 | * sizeof (time_t)); |
288 | types = (struct ttinfo *) ((char *) transitions + types_idx); |
289 | zone_names = (char *) types + num_types * sizeof (struct ttinfo); |
290 | leaps = (struct leap *) ((char *) transitions + leaps_idx); |
291 | if (sizeof (time_t) == 8 && trans_width == 8) |
292 | tzspec = (char *) leaps + num_leaps * sizeof (struct leap) + extra; |
293 | else |
294 | tzspec = NULL; |
295 | if (extra > 0) |
296 | *extrap = (char *) &leaps[num_leaps]; |
297 | |
298 | if (sizeof (time_t) == 4 || __builtin_expect (trans_width == 8, 1)) |
299 | { |
300 | if (__builtin_expect (__fread_unlocked (transitions, trans_width + 1, |
301 | num_transitions, f) |
302 | != num_transitions, 0)) |
303 | goto lose; |
304 | } |
305 | else |
306 | { |
307 | if (__builtin_expect (__fread_unlocked (transitions, 4, |
308 | num_transitions, f) |
309 | != num_transitions, 0) |
310 | || __builtin_expect (__fread_unlocked (type_idxs, 1, num_transitions, |
311 | f) != num_transitions, 0)) |
312 | goto lose; |
313 | } |
314 | |
315 | /* Check for bogus indices in the data file, so we can hereafter |
316 | safely use type_idxs[T] as indices into `types' and never crash. */ |
317 | for (i = 0; i < num_transitions; ++i) |
318 | if (__glibc_unlikely (type_idxs[i] >= num_types)) |
319 | goto lose; |
320 | |
321 | if ((BYTE_ORDER != BIG_ENDIAN && (sizeof (time_t) == 4 || trans_width == 4)) |
322 | || (BYTE_ORDER == BIG_ENDIAN && sizeof (time_t) == 8 |
323 | && trans_width == 4)) |
324 | { |
325 | /* Decode the transition times, stored as 4-byte integers in |
326 | network (big-endian) byte order. We work from the end of |
327 | the array so as not to clobber the next element to be |
328 | processed when sizeof (time_t) > 4. */ |
329 | i = num_transitions; |
330 | while (i-- > 0) |
331 | transitions[i] = decode ((char *) transitions + i * 4); |
332 | } |
333 | else if (BYTE_ORDER != BIG_ENDIAN && sizeof (time_t) == 8) |
334 | { |
335 | /* Decode the transition times, stored as 8-byte integers in |
336 | network (big-endian) byte order. */ |
337 | for (i = 0; i < num_transitions; ++i) |
338 | transitions[i] = decode64 ((char *) transitions + i * 8); |
339 | } |
340 | |
341 | for (i = 0; i < num_types; ++i) |
342 | { |
343 | unsigned char x[4]; |
344 | int c; |
345 | if (__builtin_expect (__fread_unlocked (x, 1, |
346 | sizeof (x), f) != sizeof (x), |
347 | 0)) |
348 | goto lose; |
349 | c = getc_unlocked (f); |
350 | if (__glibc_unlikely ((unsigned int) c > 1u)) |
351 | goto lose; |
352 | types[i].isdst = c; |
353 | c = getc_unlocked (f); |
354 | if (__glibc_unlikely ((size_t) c > chars)) |
355 | /* Bogus index in data file. */ |
356 | goto lose; |
357 | types[i].idx = c; |
358 | types[i].offset = (long int) decode (x); |
359 | } |
360 | |
361 | if (__glibc_unlikely (__fread_unlocked (zone_names, 1, chars, f) != chars)) |
362 | goto lose; |
363 | |
364 | for (i = 0; i < num_leaps; ++i) |
365 | { |
366 | unsigned char x[8]; |
367 | if (__builtin_expect (__fread_unlocked (x, 1, trans_width, f) |
368 | != trans_width, 0)) |
369 | goto lose; |
370 | if (sizeof (time_t) == 4 || trans_width == 4) |
371 | leaps[i].transition = (time_t) decode (x); |
372 | else |
373 | leaps[i].transition = (time_t) decode64 (x); |
374 | |
375 | if (__glibc_unlikely (__fread_unlocked (x, 1, 4, f) != 4)) |
376 | goto lose; |
377 | leaps[i].change = (long int) decode (x); |
378 | } |
379 | |
380 | for (i = 0; i < num_isstd; ++i) |
381 | { |
382 | int c = getc_unlocked (f); |
383 | if (__glibc_unlikely (c == EOF)) |
384 | goto lose; |
385 | types[i].isstd = c != 0; |
386 | } |
387 | while (i < num_types) |
388 | types[i++].isstd = 0; |
389 | |
390 | for (i = 0; i < num_isgmt; ++i) |
391 | { |
392 | int c = getc_unlocked (f); |
393 | if (__glibc_unlikely (c == EOF)) |
394 | goto lose; |
395 | types[i].isgmt = c != 0; |
396 | } |
397 | while (i < num_types) |
398 | types[i++].isgmt = 0; |
399 | |
400 | /* Read the POSIX TZ-style information if possible. */ |
401 | if (sizeof (time_t) == 8 && tzspec != NULL) |
402 | { |
403 | /* Skip over the newline first. */ |
404 | if (getc_unlocked (f) != '\n' |
405 | || (__fread_unlocked (tzspec, 1, tzspec_len - 1, f) |
406 | != tzspec_len - 1)) |
407 | tzspec = NULL; |
408 | else |
409 | tzspec[tzspec_len - 1] = '\0'; |
410 | } |
411 | else if (sizeof (time_t) == 4 && tzhead.tzh_version[0] != '\0') |
412 | { |
413 | /* Get the TZ string. */ |
414 | if (__builtin_expect (__fread_unlocked ((void *) &tzhead, |
415 | sizeof (tzhead), 1, f) != 1, 0) |
416 | || (memcmp (tzhead.tzh_magic, TZ_MAGIC, sizeof (tzhead.tzh_magic)) |
417 | != 0)) |
418 | goto lose; |
419 | |
420 | size_t num_transitions2 = (size_t) decode (tzhead.tzh_timecnt); |
421 | size_t num_types2 = (size_t) decode (tzhead.tzh_typecnt); |
422 | size_t chars2 = (size_t) decode (tzhead.tzh_charcnt); |
423 | size_t num_leaps2 = (size_t) decode (tzhead.tzh_leapcnt); |
424 | size_t num_isstd2 = (size_t) decode (tzhead.tzh_ttisstdcnt); |
425 | size_t num_isgmt2 = (size_t) decode (tzhead.tzh_ttisgmtcnt); |
426 | |
427 | /* Position the stream before the second header. */ |
428 | size_t to_skip = (num_transitions2 * (8 + 1) |
429 | + num_types2 * 6 |
430 | + chars2 |
431 | + num_leaps2 * 12 |
432 | + num_isstd2 |
433 | + num_isgmt2); |
434 | off_t off; |
435 | if (fseek (f, to_skip, SEEK_CUR) != 0 |
436 | || (off = __ftello (f)) < 0 |
437 | || st.st_size < off + 2) |
438 | goto lose; |
439 | |
440 | tzspec_len = st.st_size - off - 1; |
441 | if (tzspec_len == 0) |
442 | goto lose; |
443 | char *tzstr = malloc (tzspec_len); |
444 | if (tzstr == NULL) |
445 | goto lose; |
446 | if (getc_unlocked (f) != '\n' |
447 | || (__fread_unlocked (tzstr, 1, tzspec_len - 1, f) |
448 | != tzspec_len - 1)) |
449 | { |
450 | free (tzstr); |
451 | goto lose; |
452 | } |
453 | tzstr[tzspec_len - 1] = '\0'; |
454 | tzspec = __tzstring (tzstr); |
455 | free (tzstr); |
456 | } |
457 | |
458 | /* Don't use an empty TZ string. */ |
459 | if (tzspec != NULL && tzspec[0] == '\0') |
460 | tzspec = NULL; |
461 | |
462 | fclose (f); |
463 | |
464 | /* First "register" all timezone names. */ |
465 | for (i = 0; i < num_types; ++i) |
466 | (void) __tzstring (&zone_names[types[i].idx]); |
467 | |
468 | /* Find the standard and daylight time offsets used by the rule file. |
469 | We choose the offsets in the types of each flavor that are |
470 | transitioned to earliest in time. */ |
471 | __tzname[0] = NULL; |
472 | __tzname[1] = NULL; |
473 | for (i = num_transitions; i > 0; ) |
474 | { |
475 | int type = type_idxs[--i]; |
476 | int dst = types[type].isdst; |
477 | |
478 | if (__tzname[dst] == NULL) |
479 | { |
480 | int idx = types[type].idx; |
481 | |
482 | __tzname[dst] = __tzstring (&zone_names[idx]); |
483 | |
484 | if (__tzname[1 - dst] != NULL) |
485 | break; |
486 | } |
487 | } |
488 | if (__tzname[0] == NULL) |
489 | { |
490 | /* This should only happen if there are no transition rules. |
491 | In this case there should be only one single type. */ |
492 | assert (num_types == 1); |
493 | __tzname[0] = __tzstring (zone_names); |
494 | } |
495 | if (__tzname[1] == NULL) |
496 | __tzname[1] = __tzname[0]; |
497 | |
498 | compute_tzname_max (chars); |
499 | |
500 | if (num_transitions == 0) |
501 | /* Use the first rule (which should also be the only one). */ |
502 | rule_stdoff = rule_dstoff = types[0].offset; |
503 | else |
504 | { |
505 | int stdoff_set = 0, dstoff_set = 0; |
506 | rule_stdoff = rule_dstoff = 0; |
507 | i = num_transitions - 1; |
508 | do |
509 | { |
510 | if (!stdoff_set && !types[type_idxs[i]].isdst) |
511 | { |
512 | stdoff_set = 1; |
513 | rule_stdoff = types[type_idxs[i]].offset; |
514 | } |
515 | else if (!dstoff_set && types[type_idxs[i]].isdst) |
516 | { |
517 | dstoff_set = 1; |
518 | rule_dstoff = types[type_idxs[i]].offset; |
519 | } |
520 | if (stdoff_set && dstoff_set) |
521 | break; |
522 | } |
523 | while (i-- > 0); |
524 | |
525 | if (!dstoff_set) |
526 | rule_dstoff = rule_stdoff; |
527 | } |
528 | |
529 | __daylight = rule_stdoff != rule_dstoff; |
530 | __timezone = -rule_stdoff; |
531 | |
532 | done: |
533 | __use_tzfile = 1; |
534 | free (new); |
535 | return; |
536 | |
537 | lose: |
538 | fclose (f); |
539 | ret_free_transitions: |
540 | free (new); |
541 | free ((void *) transitions); |
542 | transitions = NULL; |
543 | } |
544 | |
545 | /* The user specified a hand-made timezone, but not its DST rules. |
546 | We will use the names and offsets from the user, and the rules |
547 | from the TZDEFRULES file. */ |
548 | |
549 | void |
550 | __tzfile_default (const char *std, const char *dst, |
551 | long int stdoff, long int dstoff) |
552 | { |
553 | size_t stdlen = strlen (std) + 1; |
554 | size_t dstlen = strlen (dst) + 1; |
555 | size_t i; |
556 | int isdst; |
557 | char *cp; |
558 | |
559 | __tzfile_read (TZDEFRULES, stdlen + dstlen, &cp); |
560 | if (!__use_tzfile) |
561 | return; |
562 | |
563 | if (num_types < 2) |
564 | { |
565 | __use_tzfile = 0; |
566 | return; |
567 | } |
568 | |
569 | /* Ignore the zone names read from the file and use the given ones |
570 | instead. */ |
571 | __mempcpy (__mempcpy (cp, std, stdlen), dst, dstlen); |
572 | zone_names = cp; |
573 | |
574 | /* Now there are only two zones, regardless of what the file contained. */ |
575 | num_types = 2; |
576 | |
577 | /* Now correct the transition times for the user-specified standard and |
578 | daylight offsets from GMT. */ |
579 | isdst = 0; |
580 | for (i = 0; i < num_transitions; ++i) |
581 | { |
582 | struct ttinfo *trans_type = &types[type_idxs[i]]; |
583 | |
584 | /* We will use only types 0 (standard) and 1 (daylight). |
585 | Fix up this transition to point to whichever matches |
586 | the flavor of its original type. */ |
587 | type_idxs[i] = trans_type->isdst; |
588 | |
589 | if (trans_type->isgmt) |
590 | /* The transition time is in GMT. No correction to apply. */ ; |
591 | else if (isdst && !trans_type->isstd) |
592 | /* The type says this transition is in "local wall clock time", and |
593 | wall clock time as of the previous transition was DST. Correct |
594 | for the difference between the rule's DST offset and the user's |
595 | DST offset. */ |
596 | transitions[i] += dstoff - rule_dstoff; |
597 | else |
598 | /* This transition is in "local wall clock time", and wall clock |
599 | time as of this iteration is non-DST. Correct for the |
600 | difference between the rule's standard offset and the user's |
601 | standard offset. */ |
602 | transitions[i] += stdoff - rule_stdoff; |
603 | |
604 | /* The DST state of "local wall clock time" for the next iteration is |
605 | as specified by this transition. */ |
606 | isdst = trans_type->isdst; |
607 | } |
608 | |
609 | /* Now that we adjusted the transitions to the requested offsets, |
610 | reset the rule_stdoff and rule_dstoff values appropriately. They |
611 | are used elsewhere. */ |
612 | rule_stdoff = stdoff; |
613 | rule_dstoff = dstoff; |
614 | |
615 | /* Reset types 0 and 1 to describe the user's settings. */ |
616 | types[0].idx = 0; |
617 | types[0].offset = stdoff; |
618 | types[0].isdst = 0; |
619 | types[1].idx = stdlen; |
620 | types[1].offset = dstoff; |
621 | types[1].isdst = 1; |
622 | |
623 | /* Reset the zone names to point to the user's names. */ |
624 | __tzname[0] = (char *) std; |
625 | __tzname[1] = (char *) dst; |
626 | |
627 | /* Set the timezone. */ |
628 | __timezone = -types[0].offset; |
629 | |
630 | compute_tzname_max (stdlen + dstlen); |
631 | |
632 | /* Invalidate the tzfile attribute cache to force rereading |
633 | TZDEFRULES the next time it is used. */ |
634 | tzfile_dev = 0; |
635 | tzfile_ino = 0; |
636 | tzfile_mtime = 0; |
637 | } |
638 | |
639 | void |
640 | __tzfile_compute (time_t timer, int use_localtime, |
641 | long int *leap_correct, int *leap_hit, |
642 | struct tm *tp) |
643 | { |
644 | size_t i; |
645 | |
646 | if (use_localtime) |
647 | { |
648 | __tzname[0] = NULL; |
649 | __tzname[1] = NULL; |
650 | |
651 | if (__glibc_unlikely (num_transitions == 0 || timer < transitions[0])) |
652 | { |
653 | /* TIMER is before any transition (or there are no transitions). |
654 | Choose the first non-DST type |
655 | (or the first if they're all DST types). */ |
656 | i = 0; |
657 | while (i < num_types && types[i].isdst) |
658 | { |
659 | if (__tzname[1] == NULL) |
660 | __tzname[1] = __tzstring (&zone_names[types[i].idx]); |
661 | |
662 | ++i; |
663 | } |
664 | |
665 | if (i == num_types) |
666 | i = 0; |
667 | __tzname[0] = __tzstring (&zone_names[types[i].idx]); |
668 | if (__tzname[1] == NULL) |
669 | { |
670 | size_t j = i; |
671 | while (j < num_types) |
672 | if (types[j].isdst) |
673 | { |
674 | __tzname[1] = __tzstring (&zone_names[types[j].idx]); |
675 | break; |
676 | } |
677 | else |
678 | ++j; |
679 | } |
680 | } |
681 | else if (__glibc_unlikely (timer >= transitions[num_transitions - 1])) |
682 | { |
683 | if (__glibc_unlikely (tzspec == NULL)) |
684 | { |
685 | use_last: |
686 | i = num_transitions; |
687 | goto found; |
688 | } |
689 | |
690 | /* Parse the POSIX TZ-style string. */ |
691 | __tzset_parse_tz (tzspec); |
692 | |
693 | /* Convert to broken down structure. If this fails do not |
694 | use the string. */ |
695 | if (__glibc_unlikely (! __offtime (&timer, 0, tp))) |
696 | goto use_last; |
697 | |
698 | /* Use the rules from the TZ string to compute the change. */ |
699 | __tz_compute (timer, tp, 1); |
700 | |
701 | /* If tzspec comes from posixrules loaded by __tzfile_default, |
702 | override the STD and DST zone names with the ones user |
703 | requested in TZ envvar. */ |
704 | if (__glibc_unlikely (zone_names == (char *) &leaps[num_leaps])) |
705 | { |
706 | assert (num_types == 2); |
707 | __tzname[0] = __tzstring (zone_names); |
708 | __tzname[1] = __tzstring (&zone_names[strlen (zone_names) + 1]); |
709 | } |
710 | |
711 | goto leap; |
712 | } |
713 | else |
714 | { |
715 | /* Find the first transition after TIMER, and |
716 | then pick the type of the transition before it. */ |
717 | size_t lo = 0; |
718 | size_t hi = num_transitions - 1; |
719 | /* Assume that DST is changing twice a year and guess initial |
720 | search spot from it. |
721 | Half of a gregorian year has on average 365.2425 * 86400 / 2 |
722 | = 15778476 seconds. */ |
723 | i = (transitions[num_transitions - 1] - timer) / 15778476; |
724 | if (i < num_transitions) |
725 | { |
726 | i = num_transitions - 1 - i; |
727 | if (timer < transitions[i]) |
728 | { |
729 | if (i < 10 || timer >= transitions[i - 10]) |
730 | { |
731 | /* Linear search. */ |
732 | while (timer < transitions[i - 1]) |
733 | --i; |
734 | goto found; |
735 | } |
736 | hi = i - 10; |
737 | } |
738 | else |
739 | { |
740 | if (i + 10 >= num_transitions || timer < transitions[i + 10]) |
741 | { |
742 | /* Linear search. */ |
743 | while (timer >= transitions[i]) |
744 | ++i; |
745 | goto found; |
746 | } |
747 | lo = i + 10; |
748 | } |
749 | } |
750 | |
751 | /* Binary search. */ |
752 | /* assert (timer >= transitions[lo] && timer < transitions[hi]); */ |
753 | while (lo + 1 < hi) |
754 | { |
755 | i = (lo + hi) / 2; |
756 | if (timer < transitions[i]) |
757 | hi = i; |
758 | else |
759 | lo = i; |
760 | } |
761 | i = hi; |
762 | |
763 | found: |
764 | /* assert (timer >= transitions[i - 1] |
765 | && (i == num_transitions || timer < transitions[i])); */ |
766 | __tzname[types[type_idxs[i - 1]].isdst] |
767 | = __tzstring (&zone_names[types[type_idxs[i - 1]].idx]); |
768 | size_t j = i; |
769 | while (j < num_transitions) |
770 | { |
771 | int type = type_idxs[j]; |
772 | int dst = types[type].isdst; |
773 | int idx = types[type].idx; |
774 | |
775 | if (__tzname[dst] == NULL) |
776 | { |
777 | __tzname[dst] = __tzstring (&zone_names[idx]); |
778 | |
779 | if (__tzname[1 - dst] != NULL) |
780 | break; |
781 | } |
782 | |
783 | ++j; |
784 | } |
785 | |
786 | if (__glibc_unlikely (__tzname[0] == NULL)) |
787 | __tzname[0] = __tzname[1]; |
788 | |
789 | i = type_idxs[i - 1]; |
790 | } |
791 | |
792 | struct ttinfo *info = &types[i]; |
793 | __daylight = rule_stdoff != rule_dstoff; |
794 | __timezone = -rule_stdoff; |
795 | |
796 | if (__tzname[0] == NULL) |
797 | { |
798 | /* This should only happen if there are no transition rules. |
799 | In this case there should be only one single type. */ |
800 | assert (num_types == 1); |
801 | __tzname[0] = __tzstring (zone_names); |
802 | } |
803 | if (__tzname[1] == NULL) |
804 | /* There is no daylight saving time. */ |
805 | __tzname[1] = __tzname[0]; |
806 | tp->tm_isdst = info->isdst; |
807 | assert (strcmp (&zone_names[info->idx], __tzname[tp->tm_isdst]) == 0); |
808 | tp->tm_zone = __tzname[tp->tm_isdst]; |
809 | tp->tm_gmtoff = info->offset; |
810 | } |
811 | |
812 | leap: |
813 | *leap_correct = 0L; |
814 | *leap_hit = 0; |
815 | |
816 | /* Find the last leap second correction transition time before TIMER. */ |
817 | i = num_leaps; |
818 | do |
819 | if (i-- == 0) |
820 | return; |
821 | while (timer < leaps[i].transition); |
822 | |
823 | /* Apply its correction. */ |
824 | *leap_correct = leaps[i].change; |
825 | |
826 | if (timer == leaps[i].transition && /* Exactly at the transition time. */ |
827 | ((i == 0 && leaps[i].change > 0) || |
828 | leaps[i].change > leaps[i - 1].change)) |
829 | { |
830 | *leap_hit = 1; |
831 | while (i > 0 |
832 | && leaps[i].transition == leaps[i - 1].transition + 1 |
833 | && leaps[i].change == leaps[i - 1].change + 1) |
834 | { |
835 | ++*leap_hit; |
836 | --i; |
837 | } |
838 | } |
839 | } |
840 | |
841 | static void |
842 | internal_function |
843 | compute_tzname_max (size_t chars) |
844 | { |
845 | const char *p; |
846 | |
847 | p = zone_names; |
848 | do |
849 | { |
850 | const char *start = p; |
851 | while (*p != '\0') |
852 | ++p; |
853 | if ((size_t) (p - start) > __tzname_cur_max) |
854 | __tzname_cur_max = p - start; |
855 | } |
856 | while (++p < &zone_names[chars]); |
857 | } |
858 | |