Hi Guix,

attached is a draft patch to make “su”, “login”, and “slim” respect a
limits file via pam_limits.so.  This seems to work, but I found two
things that are a little odd:

* 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.

* 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”.

I’d be glad if someone could give me a hint as to what’s going on here.
It would also help if you cannot reproduce it; then it’s probably
something to do with the state of my working directory.

~~ Ricardo