bug#69401: /etc/guix/machines.scm symlink can be garbage collected

bug#69401: /etc/guix/machines.scm symlink can be garbage collected

[Efraim Flashner]

[-- Attachment #1: Type: text/plain, Size: 479 bytes --]

Some of the build nodes behind the Berlin build farm have a childhurd
which can build packages.  Unfortunately, the symlink from
/etc/guix/machines.scm to the generated file in the store to setup
offloading has been garbage collected on several of the machines.

-- 
Efraim Flashner   <efraim@flashner.co.il>   רנשלפ םירפא
GPG key = A28B F40C 3E55 1372 662D  14F7 41AA E7DC CA3D 8351
Confidentiality cannot be guaranteed on emails sent or received unencrypted

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

bug#69401: /etc/guix/machines.scm symlink can be garbage collected

[Ludovic Courtès]

Hi,

Efraim Flashner <efraim@flashner.co.il> skribis:

> Some of the build nodes behind the Berlin build farm have a childhurd
> which can build packages.  Unfortunately, the symlink from
> /etc/guix/machines.scm to the generated file in the store to setup
> offloading has been garbage collected on several of the machines.

Indeed.  Here’s an example:

--8<---------------cut here---------------start------------->8---
root@hydra-guix-108 ~# guix gc -R $(readlink -f /run/current-system) |grep machines.scm
/gnu/store/xg26iis3ydik6zxqk24cyk7h9zli1d25-machines.scm
root@hydra-guix-108 ~# ls -l /etc/guix/machines.scm
lrwxrwxrwx 1 root root 56 Mar  7 11:53 /etc/guix/machines.scm -> /gnu/store/1171q4xhph07ll3mlzlg7igcwg3c98i1-machines.scm
root@hydra-guix-108 ~# stat -L /etc/guix/machines.scm
stat: cannot statx '/etc/guix/machines.scm': No such file or directory
--8<---------------cut here---------------end--------------->8---

Here /etc/guix/machines.scm points to a different ‘machines.scm’ than
the one that is current.  The old one was removed last week:

--8<---------------cut here---------------start------------->8---
root@hydra-guix-108 ~# zgrep 1171q4xhph07ll3mlzlg7igcwg3c98i1 /var/log/mcron.log.1.gz 
2024-03-27 03:00:05 23100 guix gc -F 150G: [46%] deleting '/gnu/store/1171q4xhph07ll3mlzlg7igcwg3c98i1-machines.scm'
--8<---------------cut here---------------end--------------->8---

The /etc/guix/machines.scm link was created on the last deployment
though:

--8<---------------cut here---------------start------------->8---
root@hydra-guix-108 ~# ls -l /etc/guix/machines.scm
lrwxrwxrwx 1 root root 56 Mar  7 11:53 /etc/guix/machines.scm -> /gnu/store/1171q4xhph07ll3mlzlg7igcwg3c98i1-machines.scm
root@hydra-guix-108 ~# guix system describe
Generation 109  Mar 07 2024 11:53:30    (current)
  file name: /var/guix/profiles/system-109-link
  canonical file name: /gnu/store/5m0sjf3x0pslipcbdxm9ml99h0lbh7c8-system
  label: GNU with Linux-Libre 6.6.18
  bootloader: grub-efi
  root device: label: "my-root"
  kernel: /gnu/store/jcr3d8yy531q4i6kgkfmb0r3ghw418mc-linux-libre-6.6.18/bzImage
  channels:
    guix:
      repository URL: https://git.savannah.gnu.org/git/guix.git
      commit: 64d269b983b76553466ac93945d58c7865cf190e
  configuration file: /gnu/store/d4z76lw515padizhl62hydxwygh57p6k-configuration.scm
--8<---------------cut here---------------end--------------->8---

Could it be that the “wrong” activation snippet was run by ‘guix
deploy’?  Here we see the right one:

--8<---------------cut here---------------start------------->8---
root@hydra-guix-108 ~# grep machines.scm $(guix gc -R $(readlink -f /run/current-system) |grep activate-service)
/gnu/store/pgmb9swcx0pljhbw88mgd3zjagz5axvn-activate-service.scm:(eval-when (expand load eval) (let ((extensions (quote ())) (prepend (lambda (items lst) (let loop ((items items) (lst lst)) (if (null? items) lst (loop (cdr items) (cons (car items) (delete (car items) lst)))))))) (set! %load-path (prepend (cons "/gnu/store/pj751v3199vmv6i6sf0szp185ryzcfdg-module-import" (map (lambda (extension) (string-append extension "/share/guile/site/" (effective-version))) extensions)) %load-path)) (set! %load-compiled-path (prepend (cons "/gnu/store/iqbchmbmhmi34bwgv4sm14li9m24dpnl-module-import-compiled" (map (lambda (extension) (string-append extension "/lib/guile/" (effective-version) "/site-ccache")) extensions)) %load-compiled-path))))(begin (unless (or #f (file-exists? "/etc/guix/signing-key.pub")) (system* "/gnu/store/59y43hrlffs8hg1584vg5074jsbfhwjy-guix-1.4.0-16.aeb4943/bin/guix" "archive" "--generate-key")) (begin (use-modules (guix build utils)) (define acl-file "/etc/guix/acl") (if (file-exists? acl-file) (if (and (symbolic-link? acl-file) (store-file-name? (readlink acl-file))) (delete-file acl-file) (rename-file acl-file (string-append acl-file ".bak"))) (mkdir-p (dirname acl-file))) (symlink "/gnu/store/np3babd2h4xh4x4dvm51k6rp3xbsrzyl-acl" acl-file)) (begin (use-modules (guix build utils)) (define machines-file "/etc/guix/machines.scm") (if (file-exists? machines-file) (if (and (symbolic-link? machines-file) (store-file-name? (readlink machines-file))) (delete-file machines-file) (rename-file machines-file (string-append machines-file ".bak"))) (mkdir-p (dirname machines-file))) (symlink "/gnu/store/xg26iis3ydik6zxqk24cyk7h9zli1d25-machines.scm" machines-file)))
--8<---------------cut here---------------end--------------->8---

To be continued…

Ludo’.

bug#69401: /etc/guix/machines.scm symlink can be garbage collected

[Ludovic Courtès]

Ludovic Courtès <ludo@gnu.org> skribis:

> root@hydra-guix-108 ~# guix gc -R $(readlink -f /run/current-system) |grep machines.scm
> /gnu/store/xg26iis3ydik6zxqk24cyk7h9zli1d25-machines.scm
> root@hydra-guix-108 ~# ls -l /etc/guix/machines.scm
> lrwxrwxrwx 1 root root 56 Mar  7 11:53 /etc/guix/machines.scm -> /gnu/store/1171q4xhph07ll3mlzlg7igcwg3c98i1-machines.scm

Turns out that both files are identical, but:

  • /gnu/store/1171q4xhph07ll3mlzlg7igcwg3c98i1-machines.scm is built
    with
    /gnu/store/g8p09w6r78hhkl2rv1747pcp9zbk6fxv-guile-3.0.9/bin/guile
    (‘guile-final’ ungrafted);

  • /gnu/store/xg26iis3ydik6zxqk24cyk7h9zli1d25-machines.scm is built
    with
    /gnu/store/g49b4v7dff8xwfi7wpi8pps1ixhld3n7-guile-3.0.9/bin/guile
    (‘guile-final’ grafted).

As it turns out, <scheme-file> (used for “machines.scm”) uses
‘gexp->file’, which, unlike ‘gexp->script’, does not default to
(default-guile).  That probably explains the difference.

Ludo’.

bug#69401: /etc/guix/machines.scm symlink can be garbage collected

[Ludovic Courtès]

Ludovic Courtès <ludo@gnu.org> skribis:

> Ludovic Courtès <ludo@gnu.org> skribis:
>
>> root@hydra-guix-108 ~# guix gc -R $(readlink -f /run/current-system) |grep machines.scm
>> /gnu/store/xg26iis3ydik6zxqk24cyk7h9zli1d25-machines.scm
>> root@hydra-guix-108 ~# ls -l /etc/guix/machines.scm
>> lrwxrwxrwx 1 root root 56 Mar  7 11:53 /etc/guix/machines.scm -> /gnu/store/1171q4xhph07ll3mlzlg7igcwg3c98i1-machines.scm
>
> Turns out that both files are identical, but:
>
>   • /gnu/store/1171q4xhph07ll3mlzlg7igcwg3c98i1-machines.scm is built
>     with
>     /gnu/store/g8p09w6r78hhkl2rv1747pcp9zbk6fxv-guile-3.0.9/bin/guile
>     (‘guile-final’ ungrafted);
>
>   • /gnu/store/xg26iis3ydik6zxqk24cyk7h9zli1d25-machines.scm is built
>     with
>     /gnu/store/g49b4v7dff8xwfi7wpi8pps1ixhld3n7-guile-3.0.9/bin/guile
>     (‘guile-final’ grafted).
>
> As it turns out, <scheme-file> (used for “machines.scm”) uses
> ‘gexp->file’, which, unlike ‘gexp->script’, does not default to
> (default-guile).  That probably explains the difference.

I believe this is fixed by b30b838d5055e36be19d030db28838fec4474d98.

Ludo’.