Ricardo Wurmus <rekado@elephly.net> skribis:

> * the pam-extension procedure appears to be called more than once on the
>   same pam-service.  I added a “(format #t ...)” statement to print the
>   name of the pam-service that was passed to the procedure and the same
>   name appeared multiple times.  The order of these multiple executions
>   appears random, so we can have three times “su”, followed by one time
>   “login”, then two times “su” again, etc.  I thought service folding
>   ensured that each service extension is evaluated/applied just once.

It’s purely functional, so it doesn’t matter how many times we call it.
;-)

That said, I agree that the fact that it’s called several times suggests
we’re not doing things efficiently (presumably that’s because
‘fold-services’ is called in several places where there’s no
memoization.)  Would be worth improving it in the future.

> * pam-services “su”, “sudo”, and possibly “passwd” are not actually
>   modified when I check their names (as I do in this patch).  If I
>   extend all pam-services without checking their names they do get
>   modified.  With the attached patch the pam file for “su” does not get
>   the pam entry for “pam_limits.so”.

But it works for me!  :-)

I’ve applied the attached patch (fixes a minor syntax issue in the patch
you sent), and then did:

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix system build ~/src/configuration/pluto-configuration.scm
substitute: updating list of substitutes from 'https://mirror.hydra.gnu.org'... 100.0%
substitute: updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
La jenaj derivoj estos konstruataj:
   /gnu/store/0fxwylcmdxy7bqmjpxwqf24v2x4yr53w-system.drv
   /gnu/store/q254gqx3rgwxn98nsaz16z8rl58nhfkw-shepherd.conf.drv
   /gnu/store/517cxw8xiniwsh9bfdp389qxlm9w5jj8-activate-service.drv
   /gnu/store/ky8p3bq0xpj3lf989fz1ba3j2xycyiz6-activate.drv
   /gnu/store/ljjl4zs722flxbpip8jdssqd549g7pay-boot.drv
   /gnu/store/vz8745sdk0ph0rykxldwzmfa3a5r7cm1-etc.drv
/gnu/store/s84hvl064k494174z692wl1vaqzrygln-system
ludo@pluto ~/src/guix$ grep pam_limit /gnu/store/s84hvl064k494174z692wl1vaqzrygln-system/etc/pam.d/*
/gnu/store/s84hvl064k494174z692wl1vaqzrygln-system/etc/pam.d/login:session required pam_limits.so conf=/etc/security/limits.conf
/gnu/store/s84hvl064k494174z692wl1vaqzrygln-system/etc/pam.d/slim:session required pam_limits.so conf=/etc/security/limits.conf
/gnu/store/s84hvl064k494174z692wl1vaqzrygln-system/etc/pam.d/su:session required pam_limits.so conf=/etc/security/limits.conf
--8<---------------cut here---------------end--------------->8---

… where the configuration in question has (pam-limits-service) in its
‘services’ field.

HTH,
Ludo’.