path: root/date.c
diff options
authorJeff King <>2016-06-20 21:14:14 (GMT)
committerJunio C Hamano <>2016-06-20 22:08:07 (GMT)
commitbab748371a104c58058c0eff9f4073b710ce0355 (patch)
treed4e86d14b8944617db1a2253eaefd6b7ab40bba5 /date.c
parent36d6792157cc064607147b942c80bc3716dd339b (diff)
local_tzoffset: detect errors from tm_to_time_t
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 <> Signed-off-by: Jeff King <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'date.c')
1 files changed, 2 insertions, 0 deletions
diff --git a/date.c b/date.c
index 7c9f769..4c7aa9b 100644
--- a/date.c
+++ b/date.c
@@ -74,6 +74,8 @@ static int local_tzoffset(unsigned long time)
localtime_r(&t, &tm);
t_local = tm_to_time_t(&tm);
+ if (t_local == -1)
+ return 0; /* error; just use +0000 */
if (t_local < t) {
eastwest = -1;
offset = t - t_local;