Improve absolute symlink handling about mkosi HOT 6 OPEN

Can you add a gist or so with the full logs when running with --debug?

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Do you have any mkosi scripts that are used with your configuration? I cannot reproduce this error locally with the information you've provided. I'm assuming that /boot is not a directory in which case mkdir() is documented to fail with FileExistsError.

You can verify this by adding run(["bash"], stdin=sys.stdin, cwd=context.root) just before boot_binary.parent.mkdir(parents=True, exist_ok=True) is called and checking the boot/ path

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So I added run(["bash"], stdin=sys.stdin, cwd=context.root) and checked out /boot.

It is a symlink: /boot -> /srv/boot. I verified in our postinstall script that we create this symlink since /srv will be mutable while / is immutable. During build time, this symlink is valid.

However, at install_uki, this symlink is broken. The symlink is now pointing at the host filesystem root srv path, which doesn't exist. Is this because the env is not chroot'd? I encounter the same problem when mounting a built image onto a random path. When I chroot <build_root>, the symlinks become whole again. Is there a reason to not do this in install_uki?

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@zjackwang Please realize that I lost a lot of time investigating this because you omitted this information. Next time you should add crucial information like this in your original report.

To fix this, don't use absolute symlinks, use relative symlinks.

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So we should probably add a chase() helper function that we use to resolve paths whenever we operate on the image root directory. This helper would open an fd to "/", then chroot and chdir into the image root directory, resolve the symlink and finally chroot and chdir back to "/". That way absolute symlinks would be resolved correctly.

from mkosi.

@zjackwang Please realize that I lost a lot of time investigating this because you omitted this information. Next time you should add crucial information like this in your original report.

To fix this, don't use absolute symlinks, use relative symlinks.

Apologies for the omitted information. Confirmed relative symlinks allowed the build to succeed.

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