1 /* Copyright (C) 1991, 92, 93, 95, 96, 97, 98 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
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 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
28 #include <timezone/tzfile.h>
34 long int offset
; /* Seconds east of GMT. */
35 unsigned char isdst
; /* Used to set tm_isdst. */
36 unsigned char idx
; /* Index into `zone_names'. */
37 unsigned char isstd
; /* Transition times are in standard time. */
38 unsigned char isgmt
; /* Transition times are in GMT. */
43 time_t transition
; /* Time the transition takes effect. */
44 long int change
; /* Seconds of correction to apply. */
47 extern char * __tzstring (const char *); /* Defined in tzset.c. */
49 static struct ttinfo
*find_transition (time_t timer
) internal_function
;
50 static void compute_tzname_max (size_t) internal_function
;
52 static size_t num_transitions
;
53 static time_t *transitions
= NULL
;
54 static unsigned char *type_idxs
= NULL
;
55 static size_t num_types
;
56 static struct ttinfo
*types
= NULL
;
57 static char *zone_names
= NULL
;
58 static long int rule_stdoff
;
59 static long int rule_dstoff
;
60 static size_t num_leaps
;
61 static struct leap
*leaps
= NULL
;
66 /* Decode the four bytes at PTR as a signed integer in network byte order. */
68 decode (const void *ptr
)
70 if ((BYTE_ORDER
== BIG_ENDIAN
) && sizeof (int) == 4)
71 return *(const int *) ptr
;
72 else if (BYTE_ORDER
== LITTLE_ENDIAN
&& sizeof (int) == 4)
73 return bswap_32 (*(const int *) ptr
);
76 const unsigned char *p
= ptr
;
77 int result
= *p
& (1 << (CHAR_BIT
- 1)) ? ~0 : 0;
79 result
= (result
<< 8) | *p
++;
80 result
= (result
<< 8) | *p
++;
81 result
= (result
<< 8) | *p
++;
82 result
= (result
<< 8) | *p
++;
89 __tzfile_read (const char *file
)
91 static const char default_tzdir
[] = TZDIR
;
92 size_t num_isstd
, num_isgmt
;
100 if (transitions
!= NULL
)
101 free ((void *) transitions
);
103 if (type_idxs
!= NULL
)
104 free ((void *) type_idxs
);
107 free ((void *) types
);
109 if (zone_names
!= NULL
)
110 free ((void *) zone_names
);
113 free ((void *) leaps
);
117 /* No user specification; use the site-wide default. */
119 else if (*file
== '\0')
120 /* User specified the empty string; use UTC with no leap seconds. */
124 /* We must not allow to read an arbitrary file in a setuid
125 program. So we fail for any file which is not in the
126 directory hierachy starting at TZDIR
127 and which is not the system wide default TZDEFAULT. */
128 if (__libc_enable_secure
130 && memcmp (file
, TZDEFAULT
, sizeof TZDEFAULT
)
131 && memcmp (file
, default_tzdir
, sizeof (default_tzdir
) - 1))
132 || strstr (file
, "../") != NULL
))
133 /* This test is certainly a bit too restrictive but it should
134 catch all critical cases. */
141 unsigned int len
, tzdir_len
;
144 tzdir
= __secure_getenv ("TZDIR");
145 if (tzdir
== NULL
|| *tzdir
== '\0')
147 tzdir
= default_tzdir
;
148 tzdir_len
= sizeof (default_tzdir
) - 1;
151 tzdir_len
= strlen (tzdir
);
152 len
= strlen (file
) + 1;
153 new = (char *) __alloca (tzdir_len
+ 1 + len
);
154 tmp
= __mempcpy (new, tzdir
, tzdir_len
);
156 __mempcpy (tmp
, file
, len
);
160 f
= fopen (file
, "r");
164 if (fread_unlocked ((void *) &tzhead
, sizeof (tzhead
), 1, f
) != 1)
167 num_transitions
= (size_t) decode (tzhead
.tzh_timecnt
);
168 num_types
= (size_t) decode (tzhead
.tzh_typecnt
);
169 chars
= (size_t) decode (tzhead
.tzh_charcnt
);
170 num_leaps
= (size_t) decode (tzhead
.tzh_leapcnt
);
171 num_isstd
= (size_t) decode (tzhead
.tzh_ttisstdcnt
);
172 num_isgmt
= (size_t) decode (tzhead
.tzh_ttisgmtcnt
);
174 if (num_transitions
> 0)
176 transitions
= (time_t *) malloc (num_transitions
* sizeof (time_t));
177 if (transitions
== NULL
)
179 type_idxs
= (unsigned char *) malloc (num_transitions
);
180 if (type_idxs
== NULL
)
185 types
= (struct ttinfo
*) malloc (num_types
* sizeof (struct ttinfo
));
191 zone_names
= (char *) malloc (chars
);
192 if (zone_names
== NULL
)
197 leaps
= (struct leap
*) malloc (num_leaps
* sizeof (struct leap
));
202 if (sizeof (time_t) < 4)
205 if (fread_unlocked (transitions
, 4, num_transitions
, f
) != num_transitions
206 || fread_unlocked (type_idxs
, 1, num_transitions
, f
) != num_transitions
)
209 /* Check for bogus indices in the data file, so we can hereafter
210 safely use type_idxs[T] as indices into `types' and never crash. */
211 for (i
= 0; i
< num_transitions
; ++i
)
212 if (type_idxs
[i
] >= num_types
)
215 if (BYTE_ORDER
!= BIG_ENDIAN
|| sizeof (time_t) != 4)
217 /* Decode the transition times, stored as 4-byte integers in
218 network (big-endian) byte order. We work from the end of
219 the array so as not to clobber the next element to be
220 processed when sizeof (time_t) > 4. */
223 transitions
[i
] = decode ((char *) transitions
+ i
* 4);
226 for (i
= 0; i
< num_types
; ++i
)
229 if (fread_unlocked (x
, 1, 4, f
) != 4
230 || fread_unlocked (&types
[i
].isdst
, 1, 1, f
) != 1
231 || fread_unlocked (&types
[i
].idx
, 1, 1, f
) != 1)
233 if (types
[i
].idx
>= chars
) /* Bogus index in data file. */
235 types
[i
].offset
= (long int) decode (x
);
238 if (fread_unlocked (zone_names
, 1, chars
, f
) != chars
)
241 for (i
= 0; i
< num_leaps
; ++i
)
244 if (fread_unlocked (x
, 1, sizeof (x
), f
) != sizeof (x
))
246 leaps
[i
].transition
= (time_t) decode (x
);
247 if (fread_unlocked (x
, 1, sizeof (x
), f
) != sizeof (x
))
249 leaps
[i
].change
= (long int) decode (x
);
252 for (i
= 0; i
< num_isstd
; ++i
)
254 int c
= getc_unlocked (f
);
257 types
[i
].isstd
= c
!= 0;
259 while (i
< num_types
)
260 types
[i
++].isstd
= 0;
262 for (i
= 0; i
< num_isgmt
; ++i
)
264 int c
= getc_unlocked (f
);
267 types
[i
].isgmt
= c
!= 0;
269 while (i
< num_types
)
270 types
[i
++].isgmt
= 0;
274 /* First "register" all timezone names. */
275 for (i
= 0; i
< num_types
; ++i
)
276 (void) __tzstring (&zone_names
[types
[i
].idx
]);
278 /* Find the standard and daylight time offsets used by the rule file.
279 We choose the offsets in the types of each flavor that are
280 transitioned to earliest in time. */
283 for (i
= num_transitions
; i
> 0; )
285 int type
= type_idxs
[--i
];
286 int dst
= types
[type
].isdst
;
287 int idx
= types
[type
].idx
;
289 if (__tzname
[dst
] == NULL
)
291 __tzname
[dst
] = __tzstring (&zone_names
[idx
]);
293 if (__tzname
[1 - dst
] != NULL
)
297 if (__tzname
[0] == NULL
)
299 /* This should only happen if there are no transition rules.
300 In this case there should be only one single type. */
301 assert (num_types
== 1);
302 __tzname
[0] = __tzstring (zone_names
);
304 if (__tzname
[1] == NULL
)
305 __tzname
[1] = __tzname
[0];
307 compute_tzname_max (chars
);
309 if (num_transitions
== 0)
310 /* Use the first rule (which should also be the only one. */
311 rule_stdoff
= rule_dstoff
= types
[0].offset
;
314 rule_stdoff
= rule_dstoff
= 0;
315 for (i
= 0; i
< num_transitions
; ++i
)
317 if (!rule_stdoff
&& !types
[type_idxs
[i
]].isdst
)
318 rule_stdoff
= types
[type_idxs
[i
]].offset
;
319 if (!rule_dstoff
&& types
[type_idxs
[i
]].isdst
)
320 rule_dstoff
= types
[type_idxs
[i
]].offset
;
321 if (rule_stdoff
&& rule_dstoff
)
326 __daylight
= rule_stdoff
!= rule_dstoff
;
327 __timezone
= -rule_stdoff
;
336 /* The user specified a hand-made timezone, but not its DST rules.
337 We will use the names and offsets from the user, and the rules
338 from the TZDEFRULES file. */
341 __tzfile_default (const char *std
, const char *dst
,
342 long int stdoff
, long int dstoff
)
344 size_t stdlen
, dstlen
, i
;
347 __tzfile_read (TZDEFRULES
);
357 /* Ignore the zone names read from the file. */
360 /* Use the names the user specified. */
361 stdlen
= strlen (std
) + 1;
362 dstlen
= strlen (dst
) + 1;
363 zone_names
= malloc (stdlen
+ dstlen
);
364 if (zone_names
== NULL
)
369 __mempcpy (__mempcpy (zone_names
, std
, stdlen
), dst
, dstlen
);
371 /* Now there are only two zones, regardless of what the file contained. */
374 /* Now correct the transition times for the user-specified standard and
375 daylight offsets from GMT. */
377 for (i
= 0; i
< num_transitions
; ++i
)
379 struct ttinfo
*trans_type
= &types
[type_idxs
[i
]];
381 /* We will use only types 0 (standard) and 1 (daylight).
382 Fix up this transition to point to whichever matches
383 the flavor of its original type. */
384 type_idxs
[i
] = trans_type
->isdst
;
386 if (trans_type
->isgmt
)
387 /* The transition time is in GMT. No correction to apply. */ ;
388 else if (isdst
&& !trans_type
->isstd
)
389 /* The type says this transition is in "local wall clock time", and
390 wall clock time as of the previous transition was DST. Correct
391 for the difference between the rule's DST offset and the user's
393 transitions
[i
] += dstoff
- rule_dstoff
;
395 /* This transition is in "local wall clock time", and wall clock
396 time as of this iteration is non-DST. Correct for the
397 difference between the rule's standard offset and the user's
399 transitions
[i
] += stdoff
- rule_stdoff
;
401 /* The DST state of "local wall clock time" for the next iteration is
402 as specified by this transition. */
403 isdst
= trans_type
->isdst
;
406 /* Reset types 0 and 1 to describe the user's settings. */
408 types
[0].offset
= stdoff
;
410 types
[1].idx
= stdlen
;
411 types
[1].offset
= dstoff
;
414 /* Reset the zone names to point to the user's names. */
415 __tzname
[0] = (char *) std
;
416 __tzname
[1] = (char *) dst
;
418 /* Set the timezone. */
419 __timezone
= -types
[0].offset
;
421 compute_tzname_max (stdlen
+ dstlen
);
424 static struct ttinfo
*
426 find_transition (time_t timer
)
430 if (num_transitions
== 0 || timer
< transitions
[0])
432 /* TIMER is before any transition (or there are no transitions).
433 Choose the first non-DST type
434 (or the first if they're all DST types). */
436 while (i
< num_types
&& types
[i
].isdst
)
443 /* Find the first transition after TIMER, and
444 then pick the type of the transition before it. */
445 for (i
= 1; i
< num_transitions
; ++i
)
446 if (timer
< transitions
[i
])
448 i
= type_idxs
[i
- 1];
455 __tzfile_compute (time_t timer
, int use_localtime
,
456 long int *leap_correct
, int *leap_hit
,
463 struct ttinfo
*info
= find_transition (timer
);
464 __daylight
= rule_stdoff
!= rule_dstoff
;
465 __timezone
= -rule_stdoff
;
468 for (i
= num_transitions
; i
> 0; )
470 int type
= type_idxs
[--i
];
471 int dst
= types
[type
].isdst
;
472 int idx
= types
[type
].idx
;
474 if (__tzname
[dst
] == NULL
)
476 __tzname
[dst
] = __tzstring (&zone_names
[idx
]);
478 if (__tzname
[1 - dst
] != NULL
)
482 if (__tzname
[0] == NULL
)
484 /* This should only happen if there are no transition rules.
485 In this case there should be only one single type. */
486 assert (num_types
== 1);
487 __tzname
[0] = __tzstring (zone_names
);
489 if (__tzname
[1] == NULL
)
490 /* There is no daylight saving time. */
491 __tzname
[1] = __tzname
[0];
492 tp
->tm_isdst
= info
->isdst
;
493 tp
->tm_zone
= &zone_names
[info
->idx
];
494 tp
->tm_gmtoff
= info
->offset
;
500 /* Find the last leap second correction transition time before TIMER. */
505 while (timer
< leaps
[i
].transition
);
507 /* Apply its correction. */
508 *leap_correct
= leaps
[i
].change
;
510 if (timer
== leaps
[i
].transition
&& /* Exactly at the transition time. */
511 ((i
== 0 && leaps
[i
].change
> 0) ||
512 leaps
[i
].change
> leaps
[i
- 1].change
))
516 && leaps
[i
].transition
== leaps
[i
- 1].transition
+ 1
517 && leaps
[i
].change
== leaps
[i
- 1].change
+ 1)
529 compute_tzname_max (size_t chars
)
531 extern size_t __tzname_cur_max
; /* Defined in tzset.c. */
538 const char *start
= p
;
541 if ((size_t) (p
- start
) > __tzname_cur_max
)
542 __tzname_cur_max
= p
- start
;
544 while (++p
< &zone_names
[chars
]);