mirrors/git
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

local_tzoffset: detect errors from tm_to_time_t

Browse Source 
When we want to know the local timezone offset at a given
timestamp, we compute it by asking for localtime() at the
given time, and comparing the offset to GMT at that time.
However, there's some juggling between time_t and "struct
tm" which happens, which involves calling our own
tm_to_time_t().

If that function returns an error (e.g., because it only
handles dates up to the year 2099), it returns "-1", which
we treat as a time_t, and is clearly bogus, leading to
bizarre timestamps (that seem to always adjust the time back
to (time_t)(uint32_t)-1, in the year 2106).

It's not a good idea for local_tzoffset() to simply die
here; it would make it hard to run "git log" on a repository
with funny timestamps. Instead, let's just treat such cases
as "zero offset".

Reported-by: Norbert Kiesel <nkiesel@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King
2016-06-20 17:14:14 -04:00
committed by Junio C Hamano
parent 36d6792157
commit bab748371a
2 changed files with 7 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
date.c
View File

@ -74,6 +74,8 @@ static int local_tzoffset(unsigned long time)
localtime_r(&t, &tm); localtime_r(&t, &tm);
t_local = tm_to_time_t(&tm); t_local = tm_to_time_t(&tm);
if (t_local == -1)
return 0; /* error; just use +0000 */
if (t_local < t) { if (t_local < t) {
eastwest = -1; eastwest = -1;
offset = t - t_local; offset = t - t_local;

5
t/t0006-date.sh
View File

@ -48,6 +48,11 @@ check_show default "$TIME" 'Wed Jun 15 16:13:20 2016 +0200'
check_show raw "$TIME" '1466000000 +0200' check_show raw "$TIME" '1466000000 +0200'
check_show iso-local "$TIME" '2016-06-15 14:13:20 +0000' check_show iso-local "$TIME" '2016-06-15 14:13:20 +0000'
# arbitrary time absurdly far in the future
FUTURE="5758122296 -0400"
check_show iso "$FUTURE" "2152-06-19 18:24:56 -0400"
check_show iso-local "$FUTURE" "2152-06-19 22:24:56 +0000"
check_parse() { check_parse() {
echo "$1 -> $2" >expect echo "$1 -> $2" >expect
test_expect_${4:-success} "parse date ($1${3:+ TZ=$3})" " test_expect_${4:-success} "parse date ($1${3:+ TZ=$3})" "