bug#63921: Activation snippets in reverse order, prevent boot

["Ludovic Courtès" <ludo@gnu.org>]

Ludovic Courtès <ludo@gnu.org> skribis:

> Booting a system reconfigured from
> eed55a6544d5bda2245ec853e5fa4b28e1865bea fails with shepherd saying:
>
>   error: while opening socket '/var/run/shepherd/socket': Address already in use
>
> The root cause appears to be that the ‘boot’ program has expressions
> reversed:
>
> $ guix gc --references $(guix gc --derivers $(readlink -f /var/guix/profiles/system-236-link)) | grep boot
> /gnu/store/21ldhyrpji6lkkdxi4lgr5k9l5fr2b7l-boot.drv
> $ cat $(guix build /gnu/store/21ldhyrpji6lkkdxi4lgr5k9l5fr2b7l-boot.drv)
> (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/pql80c2hy38bb60c68sng74s4xa35vwk-module-import-compiled" (map (lambda (extension) (string-append extension "/lib/guile/" (effective-version) "/site-ccache")) extensions)) %load-compiled-path))))(begin (begin (false-if-exception (delete-file "/run/booted-system")) (symlink (canonicalize-path "/run/current-system") "/run/booted-system") (let loop ((fd 3)) (when (< fd 1024) (false-if-exception (let ((flags (fcntl fd F_GETFD))) (when (zero? (logand flags FD_CLOEXEC)) (fcntl fd F_SETFD (logior FD_CLOEXEC flags))))) (loop (+ fd 1)))) (execl "/gnu/store/wj5i6x3xgai7p8whwqybxwqdjdbmbzha-shepherd-0.10.99-git/bin/shepherd" "shepherd" "--config" "/gnu/store/gnjghlc3n5qbala5jfdslgfi0n3vy8v7-shepherd.conf")) (primitive-load "/gnu/store/riabgidmf6fh76klc1yam7k9j1478vvw-activate.scm") (begin (use-modules (guix build utils)) (letrec-syntax ((fail-safe (syntax-rules () ((_ exp rest ...) (begin (catch (quote system-error) (lambda () exp) (const #f)) (fail-safe rest ...))) ((_) #t)))) (fail-safe (delete-file "/etc/group.lock") (delete-file "/etc/passwd.lock") (delete-file "/etc/.pwd.lock") (setenv "GUIX_LOCPATH" "/gnu/store/5fmqijrs5f7vx8mc2q2pmq26yvhb74sm-glibc-utf8-locales-2.35/lib/locale") (setlocale LC_CTYPE "en_US.utf8") (delete-file-recursively "/tmp") (delete-file-recursively "/var/run") (mkdir "/tmp") (chmod "/tmp" 1023) (mkdir "/var/run") (chmod "/var/run" 493) (delete-file-recursively "/run/udev/watch.old")))))
>
> Namely, (execl "…/bin/shepherd") comes before the cleanup expressions,
> which is why /var/run/shepherd/socket is still around when we boot.

Fixed in 181951207339508789b28ba7cb914f983319920f.

The regression came from dbbc7e946131ba257728f1d05b96c4339b7ee88b, which
led ‘modify-services’ to change the order of services (something I had
completely overlooked while reviewing, apologies!).  I ended up
rewriting ‘modify-services’.  Good news is we now have tests for this.

Ludo’.