normalize mtime

[katexochen]

First part of the implementation of #687

If set, the time stamp from SOURCE_DATE_EPOCH is used to normalize mtime of files. We also need to pass the environment trough when mkosi is invoking itself.

[keszybz]

LGTM.

[keszybz]

Oh, and please put the text that is now the description of the pull request in the commit message. Signed-off-by is not defined by mkosi, so that can be dropped.

[DaanDeMeyer]

We should normalize the mtime before calling make_tar() or make_cpio() instead of doing it inside those functions

[malt3]

We should normalize the mtime before calling make_tar() or make_cpio() instead of doing it inside those functions

The reason we did it this way is that there is a high probability that the code becomes incorrect over time otherwise.

We noticed that we need to normalize mtimes multiple times during a build since cpios for example are created during the build (and need normalized mtimes), after which files in the sysroot are modified (requiring us to normalize mtimes again).
If we place this code in make_tar, make_cpio and make_image, there is no chance for file modifications between normalizing mtimes and creating the archive / partitions.

[DaanDeMeyer]

Hmm this seems to granular, we should just normalize the mtimes of /boot and /efi again before we call make_image() again instead of doing it for each invididual file

[DaanDeMeyer]

Ah and maybe also modify load_environment() to pick up SOURCE_DATE_EPOCH from the environment mkosi is invoked from

[DaanDeMeyer]

Sorry for the many rounds, but I realized we should make this a separate setting so it doesn't have to be configured explicitly via the environment. So what I would suggest is the following:

1. Introduce a new setting SourceDateEpoch, it's parse function should be more or less identical to the logic you have in the MkosiState constructor now.
2. Add a default_factory function for SourceDateEpoch that initializes it from the configured environment (Environment=) or the host environment (in that order).
3. Instead of passing state.source_date_epoch to normalize_mtime(), pass state.config.source_date_epoch to normalize_mtime().

[DaanDeMeyer]

Almost there

[DaanDeMeyer]

Found one more thing

[malt3]

Stop. Do not merge. I'm quite sure I found a missing int -> str conversion issue. I'll perform some more tests.

EDIT: Alright. Works as expected now. Sorry for that.

[DaanDeMeyer]

Thanks for contributing!