1 /* Copyright (C) 1991,92,93,95,96,97,98,99 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 static struct ttinfo
*find_transition (time_t timer
) internal_function
;
48 static void compute_tzname_max (size_t) internal_function
;
50 static size_t num_transitions
;
51 static time_t *transitions
;
52 static unsigned char *type_idxs
;
53 static size_t num_types
;
54 static struct ttinfo
*types
;
55 static char *zone_names
;
56 static long int rule_stdoff
;
57 static long int rule_dstoff
;
58 static size_t num_leaps
;
59 static struct leap
*leaps
;
64 /* Decode the four bytes at PTR as a signed integer in network byte order. */
66 decode (const void *ptr
)
68 if ((BYTE_ORDER
== BIG_ENDIAN
) && sizeof (int) == 4)
69 return *(const int *) ptr
;
70 else if (BYTE_ORDER
== LITTLE_ENDIAN
&& sizeof (int) == 4)
71 return bswap_32 (*(const int *) ptr
);
74 const unsigned char *p
= ptr
;
75 int result
= *p
& (1 << (CHAR_BIT
- 1)) ? ~0 : 0;
77 result
= (result
<< 8) | *p
++;
78 result
= (result
<< 8) | *p
++;
79 result
= (result
<< 8) | *p
++;
80 result
= (result
<< 8) | *p
++;
87 __tzfile_read (const char *file
, size_t extra
, char **extrap
)
89 static const char default_tzdir
[] = TZDIR
;
90 size_t num_isstd
, num_isgmt
;
101 if (transitions
!= NULL
)
102 free ((void *) transitions
);
106 /* No user specification; use the site-wide default. */
108 else if (*file
== '\0')
109 /* User specified the empty string; use UTC with no leap seconds. */
113 /* We must not allow to read an arbitrary file in a setuid
114 program. So we fail for any file which is not in the
115 directory hierachy starting at TZDIR
116 and which is not the system wide default TZDEFAULT. */
117 if (__libc_enable_secure
119 && memcmp (file
, TZDEFAULT
, sizeof TZDEFAULT
)
120 && memcmp (file
, default_tzdir
, sizeof (default_tzdir
) - 1))
121 || strstr (file
, "../") != NULL
))
122 /* This test is certainly a bit too restrictive but it should
123 catch all critical cases. */
130 unsigned int len
, tzdir_len
;
133 tzdir
= __secure_getenv ("TZDIR");
134 if (tzdir
== NULL
|| *tzdir
== '\0')
136 tzdir
= default_tzdir
;
137 tzdir_len
= sizeof (default_tzdir
) - 1;
140 tzdir_len
= strlen (tzdir
);
141 len
= strlen (file
) + 1;
142 new = (char *) __alloca (tzdir_len
+ 1 + len
);
143 tmp
= __mempcpy (new, tzdir
, tzdir_len
);
145 memcpy (tmp
, file
, len
);
149 f
= fopen (file
, "r");
153 if (fread_unlocked ((void *) &tzhead
, sizeof (tzhead
), 1, f
) != 1)
156 num_transitions
= (size_t) decode (tzhead
.tzh_timecnt
);
157 num_types
= (size_t) decode (tzhead
.tzh_typecnt
);
158 chars
= (size_t) decode (tzhead
.tzh_charcnt
);
159 num_leaps
= (size_t) decode (tzhead
.tzh_leapcnt
);
160 num_isstd
= (size_t) decode (tzhead
.tzh_ttisstdcnt
);
161 num_isgmt
= (size_t) decode (tzhead
.tzh_ttisgmtcnt
);
163 total_size
= num_transitions
* (sizeof (time_t) + 1);
164 total_size
= ((total_size
+ __alignof__ (struct ttinfo
) - 1)
165 & ~(__alignof__ (struct ttinfo
) - 1));
166 types_idx
= total_size
;
167 total_size
+= num_types
* sizeof (struct ttinfo
) + chars
;
168 total_size
= ((total_size
+ __alignof__ (struct leap
) - 1)
169 & ~(__alignof__ (struct leap
) - 1));
170 leaps_idx
= total_size
;
171 total_size
+= num_leaps
* sizeof (struct leap
);
172 /* This is for the extra memory required by the caller. */
175 transitions
= (time_t *) malloc (total_size
);
176 if (transitions
== NULL
)
179 type_idxs
= (unsigned char *) transitions
+ (num_transitions
181 types
= (struct ttinfo
*) ((char *) transitions
+ types_idx
);
182 zone_names
= (char *) types
+ num_types
* sizeof (struct ttinfo
);
183 leaps
= (struct leap
*) ((char *) transitions
+ leaps_idx
);
185 *extrap
= (char *) &leaps
[num_leaps
];
187 if (sizeof (time_t) < 4)
190 if (sizeof (time_t) == 4)
192 if (fread_unlocked (transitions
, 1, (4 + 1) * num_transitions
, f
)
193 != (4 + 1) * num_transitions
)
198 if (fread_unlocked (transitions
, 4, num_transitions
, f
)
200 || fread_unlocked (type_idxs
, 1, num_transitions
, f
)
205 /* Check for bogus indices in the data file, so we can hereafter
206 safely use type_idxs[T] as indices into `types' and never crash. */
207 for (i
= 0; i
< num_transitions
; ++i
)
208 if (type_idxs
[i
] >= num_types
)
211 if (BYTE_ORDER
!= BIG_ENDIAN
|| sizeof (time_t) != 4)
213 /* Decode the transition times, stored as 4-byte integers in
214 network (big-endian) byte order. We work from the end of
215 the array so as not to clobber the next element to be
216 processed when sizeof (time_t) > 4. */
219 transitions
[i
] = decode ((char *) transitions
+ i
* 4);
222 for (i
= 0; i
< num_types
; ++i
)
226 if (fread_unlocked (x
, 1, sizeof (x
), f
) != sizeof (x
))
228 c
= getc_unlocked (f
);
229 if ((unsigned int) c
> 1u)
232 c
= getc_unlocked (f
);
233 if ((size_t) c
> chars
) /* Bogus index in data file. */
236 types
[i
].offset
= (long int) decode (x
);
239 if (fread_unlocked (zone_names
, 1, chars
, f
) != chars
)
242 for (i
= 0; i
< num_leaps
; ++i
)
245 if (fread_unlocked (x
, 1, sizeof (x
), f
) != sizeof (x
))
247 leaps
[i
].transition
= (time_t) decode (x
);
248 if (fread_unlocked (x
, 1, sizeof (x
), f
) != sizeof (x
))
250 leaps
[i
].change
= (long int) decode (x
);
253 for (i
= 0; i
< num_isstd
; ++i
)
255 int c
= getc_unlocked (f
);
258 types
[i
].isstd
= c
!= 0;
260 while (i
< num_types
)
261 types
[i
++].isstd
= 0;
263 for (i
= 0; i
< num_isgmt
; ++i
)
265 int c
= getc_unlocked (f
);
268 types
[i
].isgmt
= c
!= 0;
270 while (i
< num_types
)
271 types
[i
++].isgmt
= 0;
275 /* First "register" all timezone names. */
276 for (i
= 0; i
< num_types
; ++i
)
277 (void) __tzstring (&zone_names
[types
[i
].idx
]);
279 /* Find the standard and daylight time offsets used by the rule file.
280 We choose the offsets in the types of each flavor that are
281 transitioned to earliest in time. */
284 for (i
= num_transitions
; i
> 0; )
286 int type
= type_idxs
[--i
];
287 int dst
= types
[type
].isdst
;
289 if (__tzname
[dst
] == NULL
)
291 int idx
= types
[type
].idx
;
293 __tzname
[dst
] = __tzstring (&zone_names
[idx
]);
295 if (__tzname
[1 - dst
] != NULL
)
299 if (__tzname
[0] == NULL
)
301 /* This should only happen if there are no transition rules.
302 In this case there should be only one single type. */
303 assert (num_types
== 1);
304 __tzname
[0] = __tzstring (zone_names
);
306 if (__tzname
[1] == NULL
)
307 __tzname
[1] = __tzname
[0];
309 compute_tzname_max (chars
);
311 if (num_transitions
== 0)
312 /* Use the first rule (which should also be the only one). */
313 rule_stdoff
= rule_dstoff
= types
[0].offset
;
316 int stdoff_set
= 0, dstoff_set
= 0;
317 rule_stdoff
= rule_dstoff
= 0;
318 i
= num_transitions
- 1;
321 if (!stdoff_set
&& !types
[type_idxs
[i
]].isdst
)
324 rule_stdoff
= types
[type_idxs
[i
]].offset
;
326 else if (!dstoff_set
&& types
[type_idxs
[i
]].isdst
)
329 rule_dstoff
= types
[type_idxs
[i
]].offset
;
331 if (stdoff_set
&& dstoff_set
)
337 rule_dstoff
= rule_stdoff
;
340 __daylight
= rule_stdoff
!= rule_dstoff
;
341 __timezone
= -rule_stdoff
;
350 /* The user specified a hand-made timezone, but not its DST rules.
351 We will use the names and offsets from the user, and the rules
352 from the TZDEFRULES file. */
355 __tzfile_default (const char *std
, const char *dst
,
356 long int stdoff
, long int dstoff
)
358 size_t stdlen
= strlen (std
) + 1;
359 size_t dstlen
= strlen (dst
) + 1;
364 __tzfile_read (TZDEFRULES
, stdlen
+ dstlen
, &cp
);
374 /* Ignore the zone names read from the file and use the given ones
376 __mempcpy (__mempcpy (cp
, std
, stdlen
), dst
, dstlen
);
379 /* Now there are only two zones, regardless of what the file contained. */
382 /* Now correct the transition times for the user-specified standard and
383 daylight offsets from GMT. */
385 for (i
= 0; i
< num_transitions
; ++i
)
387 struct ttinfo
*trans_type
= &types
[type_idxs
[i
]];
389 /* We will use only types 0 (standard) and 1 (daylight).
390 Fix up this transition to point to whichever matches
391 the flavor of its original type. */
392 type_idxs
[i
] = trans_type
->isdst
;
394 if (trans_type
->isgmt
)
395 /* The transition time is in GMT. No correction to apply. */ ;
396 else if (isdst
&& !trans_type
->isstd
)
397 /* The type says this transition is in "local wall clock time", and
398 wall clock time as of the previous transition was DST. Correct
399 for the difference between the rule's DST offset and the user's
401 transitions
[i
] += dstoff
- rule_dstoff
;
403 /* This transition is in "local wall clock time", and wall clock
404 time as of this iteration is non-DST. Correct for the
405 difference between the rule's standard offset and the user's
407 transitions
[i
] += stdoff
- rule_stdoff
;
409 /* The DST state of "local wall clock time" for the next iteration is
410 as specified by this transition. */
411 isdst
= trans_type
->isdst
;
414 /* Reset types 0 and 1 to describe the user's settings. */
416 types
[0].offset
= stdoff
;
418 types
[1].idx
= stdlen
;
419 types
[1].offset
= dstoff
;
422 /* Reset the zone names to point to the user's names. */
423 __tzname
[0] = (char *) std
;
424 __tzname
[1] = (char *) dst
;
426 /* Set the timezone. */
427 __timezone
= -types
[0].offset
;
429 compute_tzname_max (stdlen
+ dstlen
);
432 static struct ttinfo
*
434 find_transition (time_t timer
)
438 if (num_transitions
== 0 || timer
< transitions
[0])
440 /* TIMER is before any transition (or there are no transitions).
441 Choose the first non-DST type
442 (or the first if they're all DST types). */
444 while (i
< num_types
&& types
[i
].isdst
)
451 /* Find the first transition after TIMER, and
452 then pick the type of the transition before it. */
453 for (i
= 1; i
< num_transitions
; ++i
)
454 if (timer
< transitions
[i
])
456 i
= type_idxs
[i
- 1];
463 __tzfile_compute (time_t timer
, int use_localtime
,
464 long int *leap_correct
, int *leap_hit
,
471 struct ttinfo
*info
= find_transition (timer
);
472 __daylight
= rule_stdoff
!= rule_dstoff
;
473 __timezone
= -rule_stdoff
;
476 for (i
= num_transitions
; i
> 0; )
478 int type
= type_idxs
[--i
];
479 int dst
= types
[type
].isdst
;
480 int idx
= types
[type
].idx
;
482 if (__tzname
[dst
] == NULL
)
484 __tzname
[dst
] = __tzstring (&zone_names
[idx
]);
486 if (__tzname
[1 - dst
] != NULL
)
490 if (__tzname
[0] == NULL
)
492 /* This should only happen if there are no transition rules.
493 In this case there should be only one single type. */
494 assert (num_types
== 1);
495 __tzname
[0] = __tzstring (zone_names
);
497 if (__tzname
[1] == NULL
)
498 /* There is no daylight saving time. */
499 __tzname
[1] = __tzname
[0];
500 tp
->tm_isdst
= info
->isdst
;
501 tp
->tm_zone
= __tzstring (&zone_names
[info
->idx
]);
502 tp
->tm_gmtoff
= info
->offset
;
508 /* Find the last leap second correction transition time before TIMER. */
513 while (timer
< leaps
[i
].transition
);
515 /* Apply its correction. */
516 *leap_correct
= leaps
[i
].change
;
518 if (timer
== leaps
[i
].transition
&& /* Exactly at the transition time. */
519 ((i
== 0 && leaps
[i
].change
> 0) ||
520 leaps
[i
].change
> leaps
[i
- 1].change
))
524 && leaps
[i
].transition
== leaps
[i
- 1].transition
+ 1
525 && leaps
[i
].change
== leaps
[i
- 1].change
+ 1)
537 compute_tzname_max (size_t chars
)
544 const char *start
= p
;
547 if ((size_t) (p
- start
) > __tzname_cur_max
)
548 __tzname_cur_max
= p
- start
;
550 while (++p
< &zone_names
[chars
]);
553 /* This function is only called when we are checking for memory leaks. */
557 if (transitions
!= NULL
)
558 free ((void *) transitions
);
561 /* Make sure all allocated data is freed before exiting. */
562 text_set_element (__libc_subfreeres
, freeres
);