[U-Boot] [PATCH v3 2/2] Makefile: Add SOURCE_DATE_TZ

[Chris Packham]

On Wed, Aug 26, 2015 at 12:09 AM, Paul Kocialkowski <contact at paulk.fr> wrote:
> Le jeudi 13 août 2015 à 18:08 +1200, Chris Packham a écrit :
>> Along with SOURCE_DATE_EPOCH SOURCE_DATE_TZ can be used to recreate a
>> build with a specific date timestamp. This allows the verification of
>> source supplied with a pre-compiled binary.
>>
>> If SOURCE_DATE_EPOCH is supplied SOURCE_DATE_TZ can be used to specify
>> what will appear in the output of the version command. If SOURCE_DATE_TZ
>> is not specified UTC will be used.  SOURCE_DATE_TZ on it's own will not
>> have an affect.
>
> I advise against merging this patch given Ximin Luo's comments on v1, at
> least until this has been properly discussed with the reproducible team
> and a precise meaning for it has been agreed on.
>

I'm happy to go along with that. 1/2 of this series was the "fix". 2/2
just kind of came up as part of the discussion that followed. Tom, can
you handle that or do you want me to send a v4 of the series with just
the first patch?

Just for my own understanding is the "reproducible team" a u-boot
thing or a debian thing? I'm not really active in any of the debian
projects so maybe someone there should pick this up if it's a debian
thing.

>> Signed-off-by: Chris Packham <judge.packham at gmail.com>
>> ---
>> This is a quick proof of concept that allows some control of how the
>> timezone is displayed. Now you can do something like
>>
>>   make SOURCE_DATE_EPOCH=12345678 SOURCE_DATE_TZ=America/Los_Angeles
>>
>>
>> Changes in v3:
>> - Drop RFC
>>
>> Changes in v2: None
>>
>>  Makefile | 7 ++++---
>>  README   | 9 ++++++---
>>  2 files changed, 10 insertions(+), 6 deletions(-)
>>
>> diff --git a/Makefile b/Makefile
>> index 3ff063a..609b595 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -1281,9 +1281,10 @@ endef
>>  define filechk_timestamp.h
>>       (if test -n "$${SOURCE_DATE_EPOCH}"; then \
>>               SOURCE_DATE="@$${SOURCE_DATE_EPOCH}"; \
>> -             LC_ALL=C date -u -d "$${SOURCE_DATE}" +'#define U_BOOT_DATE "%b %d %C%y"'; \
>> -             LC_ALL=C date -u -d "$${SOURCE_DATE}" +'#define U_BOOT_TIME "%T"'; \
>> -             LC_ALL=C date -u -d "$${SOURCE_DATE}" +'#define U_BOOT_TZ "%z"'; \
>> +             SOURCE_TZ="$${SOURCE_DATE_TZ:-UTC}"; \
>> +             TZ="$${SOURCE_TZ}" LC_ALL=C date -d "$${SOURCE_DATE}" +'#define U_BOOT_DATE "%b %d %C%y"'; \
>> +             TZ="$${SOURCE_TZ}" LC_ALL=C date -d "$${SOURCE_DATE}" +'#define U_BOOT_TIME "%T"'; \
>> +             TZ="$${SOURCE_TZ}" LC_ALL=C date -d "$${SOURCE_DATE}" +'#define U_BOOT_TZ "%z"'; \
>>       else \
>>               LC_ALL=C date +'#define U_BOOT_DATE "%b %d %C%y"'; \
>>               LC_ALL=C date +'#define U_BOOT_TIME "%T"'; \
>> diff --git a/README b/README
>> index 1bcb63c..d2e3e94 100644
>> --- a/README
>> +++ b/README
>> @@ -5087,11 +5087,14 @@ Reproducible builds
>>  In order to achieve reproducible builds, timestamps used in the U-Boot build
>>  process have to be set to a fixed value.
>>
>> -This is done using the SOURCE_DATE_EPOCH environment variable.
>> -SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration
>> -option for U-Boot or an environment variable in U-Boot.
>> +This is done using the SOURCE_DATE_EPOCH and SOURCE_DATE_TZ environment
>> +variables. These are to be set on the build host's shell, not as a
>> +configuration option for U-Boot or an environment variable in U-Boot.
>>
>>  SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC.
>> +SOURCE_DATE_TZ will default to UTC but can be set to another timezone and is
>> +used to determine how the date is displayed (tzselect(1) can be used to
>> +determine an appropriate value).
>>
>>  Building the Software:
>>  ======================
>