sysroot: Support boot counting for boot entries

[igoropaniuk]

Add support for boot counting for bootloader entries [1].
The boot counting data is stored in the name of the boot loader entry.
A boot loader entry file name may contain a plus (+) followed by a number.
This may optionally be followed by a minus (-) followed by a second number.
The dot (.) and file name suffix (conf or efi) must immediately follow.

The feature is enabled via sysroot configuration:
[sysroot]
boot-counting-tries=3

Testing:
$ ostree admin deploy 91fc19319be9e79d07159303dff125f40f10e5c25614630dcbed23d95e36f907
Copying /etc changes: 2 modified, 3 removed, 4 added
bootfs is sufficient for calculated new size: 0 bytes
Transaction complete; bootconfig swap: yes; bootversion: boot.0.1, deployment count change: 1

$ ls /boot/loader/entries
ostree-1.conf ostree-2+3.conf

[1] https://uapi-group.org/specifications/specs/boot_loader_specification/#boot-counting

[openshift-ci]

Hi @igoropaniuk. Thanks for your PR.

I'm waiting for a ostreedev member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[igoropaniuk]

This PR was created for initial feedback, I'll address the naming in the tests if needed and re-push

[cgwalters]

I love the idea of integrating here, thanks for starting this! This came up before in at least #3032

Hmm don't we need to consider how we make this configurable? Currently systemd kernel-install parses /etc/kernel/tries. (I think we should also support a /usr/lib variant of this, but that's mostly an aside). I guess we could in theory just start honoring that file too?

[igoropaniuk]

@cgwalters thanks for the feedback, my concern regarding parsing /etc/kernel/tries is that it's systemd-specific config, which is not described in https://uapi-group.org/specifications/specs/boot_loader_specification/

A can add an optional autoconf flag for that

[igoropaniuk]

@cgwalters added support for /etc/kernel/tries as suggested
I also wrapped the functionality with an autoconf flag (--enable-boot-count), which is disabled by default.

[cgwalters]

Thanks so much for working on this!

[cgwalters]

BTW, which bootloader are you looking at using this with?

[igoropaniuk]

@cgwalters EDK2 + systemd-boot

[igoropaniuk]

@cgwalters I've addressed all comments, thanks!

[igoropaniuk]

@cgwalters looks like some CI tests are still failing, but all of them are unrelated to this change, for example:

2024-10-30T16:06:09.9538403Z ERROR: tests/test-commit-sign.sh - too few tests run (expected 7, got 2)
2024-10-30T16:06:09.9539247Z ERROR: tests/test-commit-sign.sh - exited with status 1

[cgwalters]

Yes CI failures are unrelated, will look at this soon

[igoropaniuk]

The PR is not stalled, I'll get back to it tomorrow

[igoropaniuk]

@jlebon @cgwalters all comments addressed, please take a look

[igoropaniuk]

@jlebon @cgwalters all comments are addressed, any additional suggestions/objections are welcome, thanks!

BTW, I've cross-checked CI checks that failed, looks like they are unrelated again