We absolutely do not want to leave an incomplete file behind in /boot
since an incomplete initrd would render the machine unbootable. Errors
while writing are relatively common, mostly due to full /boot
partitions.
systemd-boot-builder does never attempt to re-write already existing
files which means that such situations are not fixable by re-running
nixos-rebuild etc. Instead the user needs to know about internals of the
systemd-boot and manually delete the correct file to recover from a
partially written kernel or (more commonly) initrd in /boot.
Note that this used to be a non issue since systemd-boot-builder used to
always delete all kernels and initrds before copying kernels and
initrds, so dest.exist() would always return False. This was fixed in
f2ca990558, revealing the underlying bad
assumption (that copyfile() always succeeds or fails without writing
anything).
The solution is to write to a temporary file first and move it to the
destination path only after this has succeeded. This way, if an error
occurs during copying, only a file distinct from dest is left behind
which would be cleaned up by subsequent runs of remove_old_entries().
Resolves#444066.
Otherwise this gets printed to stdout when running things like
nixos-rebuild, while people rely on the toplevel store path being the only
output of such commands.
`switch-to-configuration boot` was taking suspiciously long on a machine
of mine where the boot partition is on a slow SD card. Some tracing led
me to discover that it was in fact deleting all the kernels and initrds
every time, only to rewrite them.
This turned out to be because of the naive (non-path-normalising) string
concatenation used to construct paths in `known_paths`, so all the files
were recognised as obsolete and deleted:
known_paths=['/EFI/nixos/5jz3m9df1cbxn4hzjjs3aaz8lb9vvimc-linux-6.15.7-Image.efi', '/EFI/nixos/xri8qzfvzclf89x7nfwgq248miw7jbp0-initrd-linux-6.15.7-initrd.efi', '/EFI/nixos/b18llskzrcdgw2nbib58qqcaabiik6yc-linux-6.16-Image.efi', '/EFI/nixos/mdj53j746bii1vw227dfhkyd8ajwab2w-initrd-linux-6.16-initrd.efi', '/EFI/nixos/b18llskzrcdgw2nbib58qqcaabiik6yc-linux-6.16-Image.efi', '/EFI/nixos/mdj53j746bii1vw227dfhkyd8ajwab2w-initrd-linux-6.16-initrd.efi', '/EFI/nixos/b18llskzrcdgw2nbib58qqcaabiik6yc-linux-6.16-Image.efi', '/EFI/nixos/mdj53j746bii1vw227dfhkyd8ajwab2w-initrd-linux-6.16-initrd.efi', '/EFI/nixos/5jz3m9df1cbxn4hzjjs3aaz8lb9vvimc-linux-6.15.7-Image.efi', '/EFI/nixos/1ihk03c1i5518hlgm5mnhrig2hy3hq24-initrd-linux-6.15.7-initrd.efi', '/EFI/nixos/5jz3m9df1cbxn4hzjjs3aaz8lb9vvimc-linux-6.15.7-Image.efi', '/EFI/nixos/1ihk03c1i5518hlgm5mnhrig2hy3hq24-initrd-linux-6.15.7-initrd.efi', '/EFI/nixos/5jz3m9df1cbxn4hzjjs3aaz8lb9vvimc-linux-6.15.7-Image.efi', '/EFI/nixos/1ihk03c1i5518hlgm5mnhrig2hy3hq24-initrd-linux-6.15.7-initrd.efi']
path='/boot//EFI/nixos/5jz3m9df1cbxn4hzjjs3aaz8lb9vvimc-linux-6.15.7-Image.efi'
path='/boot//EFI/nixos/xri8qzfvzclf89x7nfwgq248miw7jbp0-initrd-linux-6.15.7-initrd.efi'
path='/boot//EFI/nixos/b18llskzrcdgw2nbib58qqcaabiik6yc-linux-6.16-Image.efi'
path='/boot//EFI/nixos/mdj53j746bii1vw227dfhkyd8ajwab2w-initrd-linux-6.16-initrd.efi'
path='/boot//EFI/nixos/1ihk03c1i5518hlgm5mnhrig2hy3hq24-initrd-linux-6.15.7-initrd.efi'
This can be avoided by using pathlib.Path, which normalises paths and
generally provides a more consistent and convenient API. I therefore
went ahead and replaced all use of `str` for path handling with `Path`
in the builder. This may fix some other, similar bugs, as well, but I
haven't checked in detail.
After RFC-0125 implementation, Determinate Systems was pinged multiple
times to transfer the repository ownership of the tooling to a
vendor-neutral repository.
Unfortunately, this never manifested. Additionally, the leadership of
the NixOS project was too dysfunctional to deal with this sort of
problem. It might even still be the case up to this day.
Nonetheless, nixpkgs is about enabling end users to enact their own
policies. It would be better to live in a world where there is one
obvious choice of bootspec tooling, in the meantime, we can live in a
world where people can choose their bootspec tooling.
The Lix forge possess one fork of the Bootspec tooling:
https://git.lix.systems/lix-community/bootspec which will live its own
life from now on.
Change-Id: I00c4dd64e00b4c24f6641472902e7df60ed13b55
Signed-off-by: Raito Bezarius <masterancpp@gmail.com>
Format all Nix files using the officially approved formatter,
making the CI check introduced in the previous commit succeed:
nix-build ci -A fmt.check
This is the next step of the of the [implementation](https://github.com/NixOS/nixfmt/issues/153)
of the accepted [RFC 166](https://github.com/NixOS/rfcs/pull/166).
This commit will lead to merge conflicts for a number of PRs,
up to an estimated ~1100 (~33%) among the PRs with activity in the past 2
months, but that should be lower than what it would be without the previous
[partial treewide format](https://github.com/NixOS/nixpkgs/pull/322537).
Merge conflicts caused by this commit can now automatically be resolved while rebasing using the
[auto-rebase script](8616af08d9/maintainers/scripts/auto-rebase).
If you run into any problems regarding any of this, please reach out to the
[formatting team](https://nixos.org/community/teams/formatting/) by
pinging @NixOS/nix-formatting.
Previously, all generations for the primary system profile
read their data from the currently active one rather than
their own path, and specialisations in general all used
their parent bootspec rather than their own. This fixes both issues.
This commit still uses the parent path's build date for
specialisations, but this is more minor issue and the times
shouldn't be meaningfully different in most cases anyways.
