1 /* Copyright (C) 1991-1993,1995-2001,2003,2004,2006, 2007
2 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
23 #include <stdio_ext.h>
31 #include <timezone/tzfile.h>
34 static dev_t tzfile_dev
;
35 static ino64_t tzfile_ino
;
36 static time_t tzfile_mtime
;
40 long int offset
; /* Seconds east of GMT. */
41 unsigned char isdst
; /* Used to set tm_isdst. */
42 unsigned char idx
; /* Index into `zone_names'. */
43 unsigned char isstd
; /* Transition times are in standard time. */
44 unsigned char isgmt
; /* Transition times are in GMT. */
49 time_t transition
; /* Time the transition takes effect. */
50 long int change
; /* Seconds of correction to apply. */
53 static void compute_tzname_max (size_t) internal_function
;
55 static size_t num_transitions
;
56 libc_freeres_ptr (static time_t *transitions
);
57 static unsigned char *type_idxs
;
58 static size_t num_types
;
59 static struct ttinfo
*types
;
60 static char *zone_names
;
61 static long int rule_stdoff
;
62 static long int rule_dstoff
;
63 static size_t num_leaps
;
64 static struct leap
*leaps
;
70 /* Decode the four bytes at PTR as a signed integer in network byte order. */
72 __attribute ((always_inline
))
73 decode (const void *ptr
)
75 if (BYTE_ORDER
== BIG_ENDIAN
&& sizeof (int) == 4)
76 return *(const int *) ptr
;
77 if (sizeof (int) == 4)
78 return bswap_32 (*(const int *) ptr
);
80 const unsigned char *p
= ptr
;
81 int result
= *p
& (1 << (CHAR_BIT
- 1)) ? ~0 : 0;
83 result
= (result
<< 8) | *p
++;
84 result
= (result
<< 8) | *p
++;
85 result
= (result
<< 8) | *p
++;
86 result
= (result
<< 8) | *p
++;
93 __attribute ((always_inline
))
94 decode64 (const void *ptr
)
96 if ((BYTE_ORDER
== BIG_ENDIAN
))
97 return *(const int64_t *) ptr
;
99 return bswap_64 (*(const int64_t *) ptr
);
104 __tzfile_read (const char *file
, size_t extra
, char **extrap
)
106 static const char default_tzdir
[] = TZDIR
;
107 size_t num_isstd
, num_isgmt
;
109 struct tzhead tzhead
;
115 int was_using_tzfile
= __use_tzfile
;
119 if (sizeof (time_t) != 4 && sizeof (time_t) != 8)
125 /* No user specification; use the site-wide default. */
127 else if (*file
== '\0')
128 /* User specified the empty string; use UTC with no leap seconds. */
129 goto ret_free_transitions
;
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
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
;
149 unsigned int len
, tzdir_len
;
152 tzdir
= getenv ("TZDIR");
153 if (tzdir
== NULL
|| *tzdir
== '\0')
155 tzdir
= default_tzdir
;
156 tzdir_len
= sizeof (default_tzdir
) - 1;
159 tzdir_len
= strlen (tzdir
);
160 len
= strlen (file
) + 1;
161 new = (char *) __alloca (tzdir_len
+ 1 + len
);
162 tmp
= __mempcpy (new, tzdir
, tzdir_len
);
164 memcpy (tmp
, file
, len
);
168 /* If we were already using tzfile, check whether the file changed. */
171 && stat64 (file
, &st
) == 0
172 && tzfile_ino
== st
.st_ino
&& tzfile_dev
== st
.st_dev
173 && tzfile_mtime
== st
.st_mtime
)
180 /* Note the file is opened with cancellation in the I/O functions
182 f
= fopen (file
, "rc");
184 goto ret_free_transitions
;
186 /* Get information about the file we are actually using. */
187 if (fstat64 (fileno (f
), &st
) != 0)
190 goto ret_free_transitions
;
193 free ((void *) transitions
);
196 /* Remember the inode and device number and modification time. */
197 tzfile_dev
= st
.st_dev
;
198 tzfile_ino
= st
.st_ino
;
199 tzfile_mtime
= st
.st_mtime
;
201 /* No threads reading this stream. */
202 __fsetlocking (f
, FSETLOCKING_BYCALLER
);
205 if (__builtin_expect (fread_unlocked ((void *) &tzhead
, sizeof (tzhead
),
207 || memcmp (tzhead
.tzh_magic
, TZ_MAGIC
, sizeof (tzhead
.tzh_magic
)) != 0)
210 num_transitions
= (size_t) decode (tzhead
.tzh_timecnt
);
211 num_types
= (size_t) decode (tzhead
.tzh_typecnt
);
212 chars
= (size_t) decode (tzhead
.tzh_charcnt
);
213 num_leaps
= (size_t) decode (tzhead
.tzh_leapcnt
);
214 num_isstd
= (size_t) decode (tzhead
.tzh_ttisstdcnt
);
215 num_isgmt
= (size_t) decode (tzhead
.tzh_ttisgmtcnt
);
217 /* For platforms with 64-bit time_t we use the new format if available. */
218 if (sizeof (time_t) == 8 && trans_width
== 4
219 && tzhead
.tzh_version
[0] != '\0')
221 /* We use the 8-byte format. */
224 /* Position the stream before the second header. */
225 size_t to_skip
= (num_transitions
* (4 + 1)
231 if (fseek (f
, to_skip
, SEEK_CUR
) != 0)
237 total_size
= num_transitions
* (sizeof (time_t) + 1);
238 total_size
= ((total_size
+ __alignof__ (struct ttinfo
) - 1)
239 & ~(__alignof__ (struct ttinfo
) - 1));
240 types_idx
= total_size
;
241 total_size
+= num_types
* sizeof (struct ttinfo
) + chars
;
242 total_size
= ((total_size
+ __alignof__ (struct leap
) - 1)
243 & ~(__alignof__ (struct leap
) - 1));
244 leaps_idx
= total_size
;
245 total_size
+= num_leaps
* sizeof (struct leap
);
246 tzspec_len
= (trans_width
== 8
247 ? st
.st_size
- (ftello (f
)
248 + num_transitions
* (8 + 1)
253 + num_isgmt
) - 1 : 0);
255 /* Allocate enough memory including the extra block requested by the
257 transitions
= (time_t *) malloc (total_size
+ tzspec_len
+ extra
);
258 if (transitions
== NULL
)
261 type_idxs
= (unsigned char *) transitions
+ (num_transitions
263 types
= (struct ttinfo
*) ((char *) transitions
+ types_idx
);
264 zone_names
= (char *) types
+ num_types
* sizeof (struct ttinfo
);
265 leaps
= (struct leap
*) ((char *) transitions
+ leaps_idx
);
266 if (trans_width
== 8)
267 tzspec
= (char *) leaps
+ num_leaps
* sizeof (struct leap
) + extra
;
271 *extrap
= (char *) &leaps
[num_leaps
];
273 if (sizeof (time_t) == 4 || trans_width
== 8)
275 if (__builtin_expect (fread_unlocked (transitions
, trans_width
+ 1,
277 != num_transitions
, 0))
282 if (__builtin_expect (fread_unlocked (transitions
, 4, num_transitions
, f
)
283 != num_transitions
, 0)
284 || __builtin_expect (fread_unlocked (type_idxs
, 1, num_transitions
,
285 f
) != num_transitions
, 0))
289 /* Check for bogus indices in the data file, so we can hereafter
290 safely use type_idxs[T] as indices into `types' and never crash. */
291 for (i
= 0; i
< num_transitions
; ++i
)
292 if (__builtin_expect (type_idxs
[i
] >= num_types
, 0))
295 if ((BYTE_ORDER
!= BIG_ENDIAN
&& (sizeof (time_t) == 4 || trans_width
== 4))
296 || (BYTE_ORDER
== BIG_ENDIAN
&& sizeof (time_t) == 8
297 && trans_width
== 4))
299 /* Decode the transition times, stored as 4-byte integers in
300 network (big-endian) byte order. We work from the end of
301 the array so as not to clobber the next element to be
302 processed when sizeof (time_t) > 4. */
305 transitions
[i
] = decode ((char *) transitions
+ i
* 4);
307 else if (BYTE_ORDER
!= BIG_ENDIAN
&& sizeof (time_t) == 8)
309 /* Decode the transition times, stored as 8-byte integers in
310 network (big-endian) byte order. */
311 for (i
= 0; i
< num_transitions
; ++i
)
312 transitions
[i
] = decode64 ((char *) transitions
+ i
* 8);
315 for (i
= 0; i
< num_types
; ++i
)
319 if (__builtin_expect (fread_unlocked (x
, 1, sizeof (x
), f
) != sizeof (x
),
322 c
= getc_unlocked (f
);
323 if (__builtin_expect ((unsigned int) c
> 1u, 0))
326 c
= getc_unlocked (f
);
327 if (__builtin_expect ((size_t) c
> chars
, 0))
328 /* Bogus index in data file. */
331 types
[i
].offset
= (long int) decode (x
);
334 if (__builtin_expect (fread_unlocked (zone_names
, 1, chars
, f
) != chars
, 0))
337 for (i
= 0; i
< num_leaps
; ++i
)
340 if (__builtin_expect (fread_unlocked (x
, 1, trans_width
, f
)
343 if (sizeof (time_t) == 4 || trans_width
== 4)
344 leaps
[i
].transition
= (time_t) decode (x
);
346 leaps
[i
].transition
= (time_t) decode64 (x
);
348 if (__builtin_expect (fread_unlocked (x
, 1, 4, f
) != 4, 0))
350 leaps
[i
].change
= (long int) decode (x
);
353 for (i
= 0; i
< num_isstd
; ++i
)
355 int c
= getc_unlocked (f
);
356 if (__builtin_expect (c
== EOF
, 0))
358 types
[i
].isstd
= c
!= 0;
360 while (i
< num_types
)
361 types
[i
++].isstd
= 0;
363 for (i
= 0; i
< num_isgmt
; ++i
)
365 int c
= getc_unlocked (f
);
366 if (__builtin_expect (c
== EOF
, 0))
368 types
[i
].isgmt
= c
!= 0;
370 while (i
< num_types
)
371 types
[i
++].isgmt
= 0;
373 /* Read the POSIX TZ-style information if possible. */
376 /* Skip over the newline first. */
377 if (getc_unlocked (f
) != '\n'
378 || fread_unlocked (tzspec
, 1, tzspec_len
- 1, f
) != tzspec_len
- 1)
381 tzspec
[tzspec_len
- 1] = '\0';
386 /* First "register" all timezone names. */
387 for (i
= 0; i
< num_types
; ++i
)
388 (void) __tzstring (&zone_names
[types
[i
].idx
]);
390 /* Find the standard and daylight time offsets used by the rule file.
391 We choose the offsets in the types of each flavor that are
392 transitioned to earliest in time. */
395 for (i
= num_transitions
; i
> 0; )
397 int type
= type_idxs
[--i
];
398 int dst
= types
[type
].isdst
;
400 if (__tzname
[dst
] == NULL
)
402 int idx
= types
[type
].idx
;
404 __tzname
[dst
] = __tzstring (&zone_names
[idx
]);
406 if (__tzname
[1 - dst
] != NULL
)
410 if (__tzname
[0] == NULL
)
412 /* This should only happen if there are no transition rules.
413 In this case there should be only one single type. */
414 assert (num_types
== 1);
415 __tzname
[0] = __tzstring (zone_names
);
417 if (__tzname
[1] == NULL
)
418 __tzname
[1] = __tzname
[0];
420 compute_tzname_max (chars
);
422 if (num_transitions
== 0)
423 /* Use the first rule (which should also be the only one). */
424 rule_stdoff
= rule_dstoff
= types
[0].offset
;
427 int stdoff_set
= 0, dstoff_set
= 0;
428 rule_stdoff
= rule_dstoff
= 0;
429 i
= num_transitions
- 1;
432 if (!stdoff_set
&& !types
[type_idxs
[i
]].isdst
)
435 rule_stdoff
= types
[type_idxs
[i
]].offset
;
437 else if (!dstoff_set
&& types
[type_idxs
[i
]].isdst
)
440 rule_dstoff
= types
[type_idxs
[i
]].offset
;
442 if (stdoff_set
&& dstoff_set
)
448 rule_dstoff
= rule_stdoff
;
451 __daylight
= rule_stdoff
!= rule_dstoff
;
452 __timezone
= -rule_stdoff
;
459 ret_free_transitions
:
460 free ((void *) transitions
);
464 /* The user specified a hand-made timezone, but not its DST rules.
465 We will use the names and offsets from the user, and the rules
466 from the TZDEFRULES file. */
469 __tzfile_default (const char *std
, const char *dst
,
470 long int stdoff
, long int dstoff
)
472 size_t stdlen
= strlen (std
) + 1;
473 size_t dstlen
= strlen (dst
) + 1;
478 __tzfile_read (TZDEFRULES
, stdlen
+ dstlen
, &cp
);
488 /* Ignore the zone names read from the file and use the given ones
490 __mempcpy (__mempcpy (cp
, std
, stdlen
), dst
, dstlen
);
493 /* Now there are only two zones, regardless of what the file contained. */
496 /* Now correct the transition times for the user-specified standard and
497 daylight offsets from GMT. */
499 for (i
= 0; i
< num_transitions
; ++i
)
501 struct ttinfo
*trans_type
= &types
[type_idxs
[i
]];
503 /* We will use only types 0 (standard) and 1 (daylight).
504 Fix up this transition to point to whichever matches
505 the flavor of its original type. */
506 type_idxs
[i
] = trans_type
->isdst
;
508 if (trans_type
->isgmt
)
509 /* The transition time is in GMT. No correction to apply. */ ;
510 else if (isdst
&& !trans_type
->isstd
)
511 /* The type says this transition is in "local wall clock time", and
512 wall clock time as of the previous transition was DST. Correct
513 for the difference between the rule's DST offset and the user's
515 transitions
[i
] += dstoff
- rule_dstoff
;
517 /* This transition is in "local wall clock time", and wall clock
518 time as of this iteration is non-DST. Correct for the
519 difference between the rule's standard offset and the user's
521 transitions
[i
] += stdoff
- rule_stdoff
;
523 /* The DST state of "local wall clock time" for the next iteration is
524 as specified by this transition. */
525 isdst
= trans_type
->isdst
;
528 /* Now that we adjusted the transitions to the requested offsets,
529 reset the rule_stdoff and rule_dstoff values appropriately. They
530 are used elsewhere. */
531 rule_stdoff
= stdoff
;
532 rule_dstoff
= dstoff
;
534 /* Reset types 0 and 1 to describe the user's settings. */
536 types
[0].offset
= stdoff
;
538 types
[1].idx
= stdlen
;
539 types
[1].offset
= dstoff
;
542 /* Reset the zone names to point to the user's names. */
543 __tzname
[0] = (char *) std
;
544 __tzname
[1] = (char *) dst
;
546 /* Set the timezone. */
547 __timezone
= -types
[0].offset
;
549 compute_tzname_max (stdlen
+ dstlen
);
553 __tzfile_compute (time_t timer
, int use_localtime
,
554 long int *leap_correct
, int *leap_hit
,
564 if (num_transitions
== 0 || timer
< transitions
[0])
566 /* TIMER is before any transition (or there are no transitions).
567 Choose the first non-DST type
568 (or the first if they're all DST types). */
570 while (i
< num_types
&& types
[i
].isdst
)
572 if (__tzname
[1] == NULL
)
573 __tzname
[1] = __tzstring (&zone_names
[types
[i
].idx
]);
580 __tzname
[0] = __tzstring (&zone_names
[types
[i
].idx
]);
581 if (__tzname
[1] == NULL
)
584 while (j
< num_types
)
587 __tzname
[1] = __tzstring (&zone_names
[types
[j
].idx
]);
594 else if (timer
>= transitions
[num_transitions
- 1])
603 /* Parse the POSIX TZ-style string. */
604 __tzset_parse_tz (tzspec
);
606 /* Convert to broken down structure. If this fails do not
608 if (! __offtime (&timer
, 0, tp
))
611 /* Use the rules from the TZ string to compute the change. */
612 __tz_compute (timer
, tp
, 1);
620 /* Find the first transition after TIMER, and
621 then pick the type of the transition before it. */
623 size_t hi
= num_transitions
- 1;
624 /* Assume that DST is changing twice a year and guess initial
626 Half of a gregorian year has on average 365.2425 * 86400 / 2
627 = 15778476 seconds. */
628 i
= (transitions
[num_transitions
- 1] - timer
) / 15778476;
629 if (i
< num_transitions
)
631 i
= num_transitions
- 1 - i
;
632 if (timer
< transitions
[i
])
634 if (i
< 10 || timer
>= transitions
[i
- 10])
637 while (timer
< transitions
[i
- 1])
645 if (i
+ 10 >= num_transitions
|| timer
< transitions
[i
+ 10])
648 while (timer
>= transitions
[i
])
657 /* assert (timer >= transitions[lo] && timer < transitions[hi]); */
661 if (timer
< transitions
[i
])
669 /* assert (timer >= transitions[i - 1]
670 && (i == num_transitions || timer < transitions[i])); */
671 __tzname
[types
[type_idxs
[i
- 1]].isdst
]
672 = __tzstring (&zone_names
[types
[type_idxs
[i
- 1]].idx
]);
674 while (j
< num_transitions
)
676 int type
= type_idxs
[j
];
677 int dst
= types
[type
].isdst
;
678 int idx
= types
[type
].idx
;
680 if (__tzname
[dst
] == NULL
)
682 __tzname
[dst
] = __tzstring (&zone_names
[idx
]);
684 if (__tzname
[1 - dst
] != NULL
)
691 i
= type_idxs
[i
- 1];
694 struct ttinfo
*info
= &types
[i
];
695 __daylight
= rule_stdoff
!= rule_dstoff
;
696 __timezone
= -rule_stdoff
;
698 if (__tzname
[0] == NULL
)
700 /* This should only happen if there are no transition rules.
701 In this case there should be only one single type. */
702 assert (num_types
== 1);
703 __tzname
[0] = __tzstring (zone_names
);
705 if (__tzname
[1] == NULL
)
706 /* There is no daylight saving time. */
707 __tzname
[1] = __tzname
[0];
708 tp
->tm_isdst
= info
->isdst
;
709 assert (strcmp (&zone_names
[info
->idx
], __tzname
[tp
->tm_isdst
]) == 0);
710 tp
->tm_zone
= __tzname
[tp
->tm_isdst
];
711 tp
->tm_gmtoff
= info
->offset
;
717 /* Find the last leap second correction transition time before TIMER. */
722 while (timer
< leaps
[i
].transition
);
724 /* Apply its correction. */
725 *leap_correct
= leaps
[i
].change
;
727 if (timer
== leaps
[i
].transition
&& /* Exactly at the transition time. */
728 ((i
== 0 && leaps
[i
].change
> 0) ||
729 leaps
[i
].change
> leaps
[i
- 1].change
))
733 && leaps
[i
].transition
== leaps
[i
- 1].transition
+ 1
734 && leaps
[i
].change
== leaps
[i
- 1].change
+ 1)
744 compute_tzname_max (size_t chars
)
751 const char *start
= p
;
754 if ((size_t) (p
- start
) > __tzname_cur_max
)
755 __tzname_cur_max
= p
- start
;
757 while (++p
< &zone_names
[chars
]);