This new function returns the GMT offset relative to its
argument. It is used in this patch to fix two bugs:
1) On platforms that the tm struct excludes tm_gmtoff,
hwclock assumes a one hour DST offset. This can cause
an incorrect kernel timezone setting. For example:
Master branch tested with tm_gmtoff illustrates the correct offset:
$ TZ="Australia/Lord_Howe" hwclock --hctosys --test | grep settimeofday
Calling settimeofday(1507494204.192398, -660)
Master branch tested without tm_gmtoff has an incorrect offset:
$ TZ="Australia/Lord_Howe" hwclock --hctosys --test | grep settimeofday
Calling settimeofday(1507494249.193852, -690)
Patched tested without tm_gmtoff has the correct offset:
$ TZ="Australia/Lord_Howe" hwclock --hctosys --test | grep settimeofday
Calling settimeofday(1507494260.194208, -660)
2) ISO 8601 'extended' format requires all time elements
to use a colon (:).
Current invalid ISO 8601:
$ hwclock
2017-10-08 16:25:17.895462-0400
Patched:
$ hwclock
2017-10-08 16:25:34.141895-04:00
Also required by this change:
login-utils/last.c: increase ISO out_len and in_len by one to
accommodate the addition of the timezone colon.
Signed-off-by: J William Piggott <elseifthen@gmx.com>
Local timegm() is a replacement function in cases it is missing from libc
implementation. Hopefully the replacement is never, or very rarely, used.
CC: Ruediger Meier <ruediger.meier@ga-group.nl>
Reviewed-by: J William Piggott <elseifthen@gmx.com>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>
When timestamps are intented to be conversable back from string to binary it
is best to stick with UTC-0 timezone. This is needed in utmpdump(1).
Signed-off-by: Sami Kerola <kerolasa@iki.fi>
- use buffers rather than allocate memory
- support .usec and ,usec convention
- use strftime for timezone (we need to care about daylight
saving time)
Signed-off-by: Karel Zak <kzak@redhat.com>
