Re: 33/33: daemon: Workaround issues for the Hurd.

[Ludovic Courtès]

address@hidden skribis:

> commit c32b64950972a459af7192abd7a8bc9619c013e9
> Author: Manolis Ragkousis <address@hidden>
> AuthorDate: Wed Dec 28 02:49:22 2016 +0200
>
>     daemon: Workaround issues for the Hurd.
>     
>     This allows for native builds on the Hurd, doing
>     
>         sudo ./pre-inst-env guix-daemon --disable-chroot 
> --build-users-group=guixbuild &
>         ./pre-inst-env guix build hello
>     
>     * nix/libstore/build.cc (DerivationGoal::startBuilder)[__GNU__]: Allow
>     non-chrooted build.
>     * nix/libutil/util.cc (killUser)[__GNU__]: Avoid wait failure.

[...]

> +++ b/nix/libstore/build.cc
> @@ -1824,7 +1824,7 @@ void DerivationGoal::startBuilder()
>      }
>  
>      if (useChroot) {
> -#if CHROOT_ENABLED
> +#if CHROOT_ENABLED || __GNU__

Can we instead change the #define CHROOT_ENABLED such that
CHROOT_ENABLED is always true when __GNU__?  Also with a comment stating
that GNU supports chroot(2) without being root.

> +++ b/nix/libutil/util.cc
> @@ -872,9 +872,11 @@ void killUser(uid_t uid)
>          _exit(0);
>      });
>  
> +#if !__GNU__
>      int status = pid.wait(true);
>      if (status != 0)
>          throw Error(format("cannot kill processes for uid `%1%': %2%") % uid 
> % statusToString(status));
> +#endif

Do you know what the rationale was?  It looks like it could leave
zombies behind us.

Ludo’.