[bug#63943] The Shepherd on GNU/Hurd

Ludovic Courtès <ludo@gnu.org> skribis:

> To me it’s important so we can upgrade the Shepherd in use on GNU/Hurd
> (it’s still stuck at 0.8 because so far Fibers lacked support for
> non-Linux systems), which in turn means we can use the newer Shepherd
> APIs in its config file.  Unfortunately, while shepherd cross-builds
> and runs on GNU/Hurd, I’m not confident it “works”.  I’ll write more
> in a separate message.

The patch I ended up not including in this series is use of current
Shepherd on GNU/Hurd (attached).

Problems that I see are:

  • ‘networking’ gets stuck in ‘starting’ state.  My guess is that it
    uses ‘system*’ (the replacement provided by shepherd) and that one
    does not return because we never get SIGCHLD.

  • (@ (ice-9 threads) all-threads) says there are two threads.  That
    was already the case with 0.8, but it’s no good.

Also, I haven’t tried to run the Shepherd’s test suite natively on
GNU/Hurd; I’m sure it’d uncover problems.

Overall, I’m pessimistic about signal handling without ‘signalfd’.  We
could try to get shepherd to kinda work without ‘signalfd’ (we could
even test that code path on GNU/Linux), but that’s going to be brittle
as we can already see.

What d’ya think, comrades?

Ludo’.

Ludovic Courtès writes:

> Ludovic Courtès <ludo@gnu.org> skribis:
>
>> To me it’s important so we can upgrade the Shepherd in use on GNU/Hurd
>> (it’s still stuck at 0.8 because so far Fibers lacked support for
>> non-Linux systems), which in turn means we can use the newer Shepherd
>> APIs in its config file.  Unfortunately, while shepherd cross-builds
>> and runs on GNU/Hurd, I’m not confident it “works”.  I’ll write more
>> in a separate message.
>
> The patch I ended up not including in this series is use of current
> Shepherd on GNU/Hurd (attached).
>
> Problems that I see are:
>
>   • ‘networking’ gets stuck in ‘starting’ state.  My guess is that it
>     uses ‘system*’ (the replacement provided by shepherd) and that one
>     does not return because we never get SIGCHLD.
>
>   • (@ (ice-9 threads) all-threads) says there are two threads.  That
>     was already the case with 0.8, but it’s no good.
>
> Also, I haven’t tried to run the Shepherd’s test suite natively on
> GNU/Hurd; I’m sure it’d uncover problems.
>
> Overall, I’m pessimistic about signal handling without ‘signalfd’.  We
> could try to get shepherd to kinda work without ‘signalfd’ (we could
> even test that code path on GNU/Linux), but that’s going to be brittle
> as we can already see.
>
> What d’ya think, comrades?

It would be great, if it works ;-)

While I'd like to test it and I'm still making progress building
natively on the Hurd but it's hard to predict when I'll get to building
fibers:

--8<---------------cut here---------------start------------->8---
root@guixydevel ~/src/guix/wip-hurd# ./pre-inst-env guix build guile-fibers@1.3.1
The following derivations will be built:
  /gnu/store/rc75bjs5pjni9w6dvhjvmik55vgdk501-guile-fibers-1.3.1.drv
  /gnu/store/l9pvk6ari19l5j8bvbjij4df8rx8a943-guile-fibers-1.3.1-checkout.drv
  /gnu/store/79j9l6rxqpayvrh2fmk665xiw6izfd9v-guile-fibers-1.3.1-checkout.drv
  /gnu/store/71lgpvpmgjb40n6r5qkrk7zp5cgmc67x-guile-json-4.7.3.drv
  /gnu/store/b8wcy6aw9zsd3s7rjp6idmzzh0slp9xn-module-import-compiled.drv
  /gnu/store/kkgkbhg583zplxd75kivl3s06xp3id7i-guile-gnutls-3.7.12.drv
  /gnu/store/2nnnqgifm6kwwaard67vmlxsqg9z4dbn-guile-gnutls-3.7.12.tar.xz.drv
  /gnu/store/lxhq4z01ihalnbxp592z4mm9iyjbvb3p-texinfo-6.8.drv
  /gnu/store/78nfa0r179gs408gxf50i0q0c2cd3mi7-texinfo-6.8.tar.xz.drv
  /gnu/store/p6hq43iga4kb4g09h2baq5mdca5m5h29-git-minimal-2.40.1.drv
  /gnu/store/7j5v82rv9ar36xxnh3sk5srw1dr48azn-curl-7.85.0.drv
  /gnu/store/74n0wvcc4c8qjdalf2mw77ij3my7amcc-nghttp2-1.49.0.drv
  /gnu/store/8z7cr0bgayis4qc97n72hia0qy2y7cx9-jansson-2.14.drv
  /gnu/store/cma9bgjc8a2wx4qfrzyxbzhwhyxpabdc-python-3.10.7.drv
  /gnu/store/00rah96n5lqi6ciz6xwnp1pxjh87sxak-sqlite-3.39.3.drv
  /gnu/store/6g1l3r6bz60rbpf589wldflgnv91aiql-sqlite-autoconf-3390300.tar.xz.drv
  /gnu/store/0mwhankh574hrcyjcbpiv4vzgz79fx3d-libxext-1.3.4.drv
  /gnu/store/agp5cags2viz3i03qpgwbrvsxwzq905j-tk-8.6.12.drv
  /gnu/store/479v3x0adq8i592v84b65zp4ssz9k3k6-libxft-2.3.4.drv
  /gnu/store/6zhyims30137hinkqki2fs1r7906nys6-fontconfig-minimal-2.14.0.drv
  /gnu/store/bfxx8cznlb4hszg1qm0limhyjsv7d7yr-font-dejavu-2.37.drv
  /gnu/store/svnq4kdgyvh6zp8vb0swcnrkj039wwqy-module-import-compiled.drv
  /gnu/store/qvqxdab06klfn40bdf4fmmmflrgaah6q-tk8.6.12-src.tar.xz.drv
  /gnu/store/jzjsa7b6ly6a4wz4a9k0s66fnxv0imb0-libev-4.33.drv
  /gnu/store/bhxa1vsdx7qm2cdqwqr0j7k6zdvhnv6l-mit-krb5-1.20.drv
  /gnu/store/a552az04c0fwd1hs936gsq6ivszhiimd-krb5-1.20.tar.xz.drv
  /gnu/store/pg26yqmmv4fz2if4k6fd5hbnh5xnqy2r-libevent-2.1.12.drv
  /gnu/store/3861750mi7r1faq24va47dc6dqr122pj-python-wrapper-3.10.7.drv
--8<---------------cut here---------------end--------------->8---

most (all?) of these dependencies are on my list working towards
a self-hosting guix.

Greetings,
janneke

Janneke Nieuwenhuizen writes:

hi!

> Ludovic Courtès writes:
>
>> Ludovic Courtès <ludo@gnu.org> skribis:
>>
>>> To me it’s important so we can upgrade the Shepherd in use on GNU/Hurd
>>> (it’s still stuck at 0.8 because so far Fibers lacked support for
>>> non-Linux systems), which in turn means we can use the newer Shepherd
>>> APIs in its config file.  Unfortunately, while shepherd cross-builds
>>> and runs on GNU/Hurd, I’m not confident it “works”.  I’ll write more
>>> in a separate message.
>>
>> The patch I ended up not including in this series is use of current
>> Shepherd on GNU/Hurd (attached).
>>
>> Problems that I see are:

[..]

> It would be great, if it works ;-)
>
> While I'd like to test it and I'm still making progress building
> natively on the Hurd but it's hard to predict when I'll get to building
> fibers:

Finally up to guile-fibers@1.3.1, I broke off the test suite after 2h.

I'll retry using --verbosity=2 during the night (hopefully today or
tomorrow).

Greetings,
Janneke