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authorFlorian Weimer <fweimer@redhat.com>2018-05-11 16:30:30 +0200
committerFlorian Weimer <fweimer@redhat.com>2018-05-11 16:30:30 +0200
commitfc79706a3233b02909b1a75b1e43e40915eb5a04 (patch)
treeec929508205466117b6e68787aa38752c85a021f /time/tzfile.c
parent89aacb513eb77549a29df2638913a0f8178cf3f5 (diff)
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time: Use 64-bit time values for time zone parsing
Diffstat (limited to 'time/tzfile.c')
-rw-r--r--time/tzfile.c118
1 files changed, 38 insertions, 80 deletions
diff --git a/time/tzfile.c b/time/tzfile.c
index 3e39723148..2a385b92bc 100644
--- a/time/tzfile.c
+++ b/time/tzfile.c
@@ -44,12 +44,12 @@ struct ttinfo
struct leap
{
- time_t transition; /* Time the transition takes effect. */
+ internal_time_t transition; /* Time the transition takes effect. */
long int change; /* Seconds of correction to apply. */
};
static size_t num_transitions;
-libc_freeres_ptr (static time_t *transitions);
+libc_freeres_ptr (static internal_time_t *transitions);
static unsigned char *type_idxs;
static size_t num_types;
static struct ttinfo *types;
@@ -113,8 +113,8 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
size_t tzspec_len;
char *new = NULL;
- if (sizeof (time_t) != 4 && sizeof (time_t) != 8)
- abort ();
+ _Static_assert (sizeof (internal_time_t) == 8,
+ "internal_time_t must be eight bytes");
__use_tzfile = 0;
@@ -200,9 +200,7 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
if (__glibc_unlikely (num_isstd > num_types || num_isgmt > num_types))
goto lose;
- /* For platforms with 64-bit time_t we use the new format if available. */
- if (sizeof (time_t) == 8 && trans_width == 4
- && tzhead.tzh_version[0] != '\0')
+ if (trans_width == 4 && tzhead.tzh_version[0] != '\0')
{
/* We use the 8-byte format. */
trans_width = 8;
@@ -222,9 +220,9 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
if (__builtin_expect (num_transitions
> ((SIZE_MAX - (__alignof__ (struct ttinfo) - 1))
- / (sizeof (time_t) + 1)), 0))
+ / (sizeof (internal_time_t) + 1)), 0))
goto lose;
- total_size = num_transitions * (sizeof (time_t) + 1);
+ total_size = num_transitions * (sizeof (internal_time_t) + 1);
total_size = ((total_size + __alignof__ (struct ttinfo) - 1)
& ~(__alignof__ (struct ttinfo) - 1));
types_idx = total_size;
@@ -246,7 +244,7 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
goto lose;
total_size += num_leaps * sizeof (struct leap);
tzspec_len = 0;
- if (sizeof (time_t) == 8 && trans_width == 8)
+ if (trans_width == 8)
{
off_t rem = st.st_size - __ftello (f);
if (__builtin_expect (rem < 0
@@ -276,23 +274,23 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
/* Allocate enough memory including the extra block requested by the
caller. */
- transitions = (time_t *) malloc (total_size + tzspec_len + extra);
+ transitions = malloc (total_size + tzspec_len + extra);
if (transitions == NULL)
goto lose;
type_idxs = (unsigned char *) transitions + (num_transitions
- * sizeof (time_t));
+ * sizeof (internal_time_t));
types = (struct ttinfo *) ((char *) transitions + types_idx);
zone_names = (char *) types + num_types * sizeof (struct ttinfo);
leaps = (struct leap *) ((char *) transitions + leaps_idx);
- if (sizeof (time_t) == 8 && trans_width == 8)
+ if (trans_width == 8)
tzspec = (char *) leaps + num_leaps * sizeof (struct leap) + extra;
else
tzspec = NULL;
if (extra > 0)
*extrap = (char *) &leaps[num_leaps];
- if (sizeof (time_t) == 4 || __builtin_expect (trans_width == 8, 1))
+ if (__builtin_expect (trans_width == 8, 1))
{
if (__builtin_expect (__fread_unlocked (transitions, trans_width + 1,
num_transitions, f)
@@ -315,19 +313,17 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
if (__glibc_unlikely (type_idxs[i] >= num_types))
goto lose;
- if ((BYTE_ORDER != BIG_ENDIAN && (sizeof (time_t) == 4 || trans_width == 4))
- || (BYTE_ORDER == BIG_ENDIAN && sizeof (time_t) == 8
- && trans_width == 4))
+ if (trans_width == 4)
{
/* Decode the transition times, stored as 4-byte integers in
- network (big-endian) byte order. We work from the end of
- the array so as not to clobber the next element to be
- processed when sizeof (time_t) > 4. */
+ network (big-endian) byte order. We work from the end of the
+ array so as not to clobber the next element to be
+ processed. */
i = num_transitions;
while (i-- > 0)
transitions[i] = decode ((char *) transitions + i * 4);
}
- else if (BYTE_ORDER != BIG_ENDIAN && sizeof (time_t) == 8)
+ else if (BYTE_ORDER != BIG_ENDIAN)
{
/* Decode the transition times, stored as 8-byte integers in
network (big-endian) byte order. */
@@ -364,10 +360,10 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
if (__builtin_expect (__fread_unlocked (x, 1, trans_width, f)
!= trans_width, 0))
goto lose;
- if (sizeof (time_t) == 4 || trans_width == 4)
- leaps[i].transition = (time_t) decode (x);
+ if (trans_width == 4)
+ leaps[i].transition = decode (x);
else
- leaps[i].transition = (time_t) decode64 (x);
+ leaps[i].transition = decode64 (x);
if (__glibc_unlikely (__fread_unlocked (x, 1, 4, f) != 4))
goto lose;
@@ -395,7 +391,7 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
types[i++].isgmt = 0;
/* Read the POSIX TZ-style information if possible. */
- if (sizeof (time_t) == 8 && tzspec != NULL)
+ if (tzspec != NULL)
{
/* Skip over the newline first. */
if (__getc_unlocked (f) != '\n'
@@ -405,52 +401,6 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
else
tzspec[tzspec_len - 1] = '\0';
}
- else if (sizeof (time_t) == 4 && tzhead.tzh_version[0] != '\0')
- {
- /* Get the TZ string. */
- if (__builtin_expect (__fread_unlocked ((void *) &tzhead,
- sizeof (tzhead), 1, f) != 1, 0)
- || (memcmp (tzhead.tzh_magic, TZ_MAGIC, sizeof (tzhead.tzh_magic))
- != 0))
- goto lose;
-
- size_t num_transitions2 = (size_t) decode (tzhead.tzh_timecnt);
- size_t num_types2 = (size_t) decode (tzhead.tzh_typecnt);
- size_t chars2 = (size_t) decode (tzhead.tzh_charcnt);
- size_t num_leaps2 = (size_t) decode (tzhead.tzh_leapcnt);
- size_t num_isstd2 = (size_t) decode (tzhead.tzh_ttisstdcnt);
- size_t num_isgmt2 = (size_t) decode (tzhead.tzh_ttisgmtcnt);
-
- /* Position the stream before the second header. */
- size_t to_skip = (num_transitions2 * (8 + 1)
- + num_types2 * 6
- + chars2
- + num_leaps2 * 12
- + num_isstd2
- + num_isgmt2);
- off_t off;
- if (fseek (f, to_skip, SEEK_CUR) != 0
- || (off = __ftello (f)) < 0
- || st.st_size < off + 2)
- goto lose;
-
- tzspec_len = st.st_size - off - 1;
- if (tzspec_len == 0)
- goto lose;
- char *tzstr = malloc (tzspec_len);
- if (tzstr == NULL)
- goto lose;
- if (__getc_unlocked (f) != '\n'
- || (__fread_unlocked (tzstr, 1, tzspec_len - 1, f)
- != tzspec_len - 1))
- {
- free (tzstr);
- goto lose;
- }
- tzstr[tzspec_len - 1] = '\0';
- tzspec = __tzstring (tzstr);
- free (tzstr);
- }
/* Don't use an empty TZ string. */
if (tzspec != NULL && tzspec[0] == '\0')
@@ -630,7 +580,7 @@ __tzfile_default (const char *std, const char *dst,
}
void
-__tzfile_compute (time_t timer, int use_localtime,
+__tzfile_compute (internal_time_t timer, int use_localtime,
long int *leap_correct, int *leap_hit,
struct tm *tp)
{
@@ -685,10 +635,16 @@ __tzfile_compute (time_t timer, int use_localtime,
/* Convert to broken down structure. If this fails do not
use the string. */
- if (__glibc_unlikely (! __offtime (&timer, 0, tp)))
- goto use_last;
-
- /* Use the rules from the TZ string to compute the change. */
+ {
+ time_t truncated = timer;
+ if (__glibc_unlikely (truncated != timer
+ || ! __offtime (&truncated, 0, tp)))
+ goto use_last;
+ }
+
+ /* Use the rules from the TZ string to compute the change.
+ timer fits into time_t due to the truncation check
+ above. */
__tz_compute (timer, tp, 1);
/* If tzspec comes from posixrules loaded by __tzfile_default,
@@ -709,10 +665,12 @@ __tzfile_compute (time_t timer, int use_localtime,
then pick the type of the transition before it. */
size_t lo = 0;
size_t hi = num_transitions - 1;
- /* Assume that DST is changing twice a year and guess initial
- search spot from it.
- Half of a gregorian year has on average 365.2425 * 86400 / 2
- = 15778476 seconds. */
+ /* Assume that DST is changing twice a year and guess
+ initial search spot from it. Half of a gregorian year
+ has on average 365.2425 * 86400 / 2 = 15778476 seconds.
+ The value i can be truncated if size_t is smaller than
+ internal_time_t, but this is harmless because it is just
+ a guess. */
i = (transitions[num_transitions - 1] - timer) / 15778476;
if (i < num_transitions)
{