From: "Ludovic Courtès" <ludo@gnu.org>
To: Jan Nieuwenhuizen <janneke@gnu.org>
Cc: guix-devel@gnu.org
Subject: Re: 33/33: daemon: Workaround issues for the Hurd.
Date: Wed, 11 Mar 2020 15:50:26 +0100 [thread overview]
Message-ID: <87h7yvgd3h.fsf@gnu.org> (raw)
In-Reply-To: <87k13s2wwl.fsf@gnu.org> (Jan Nieuwenhuizen's message of "Tue, 10 Mar 2020 13:54:02 +0100")
Hi!
Jan Nieuwenhuizen <janneke@gnu.org> skribis:
>>> +#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.
>
> No, maybe Manolis knows? What I do know is why I used the patch: before
> applying this patch I could only build up to binutils-boot0.
> binutils-boot0 would always fail like so
>
> ./pre-inst-env guix build -e '(@@ (gnu packages commencement) binutils-boot0)' --no-offload
> XXX fails: Workaround for nix daemon
> phase `compress-documentation' succeeded after 0.4 seconds
> error: cannot kill processes for uid `999': Operation not permitted
> guix build: error: cannot kill processes for uid `999': failed with exit code 1
But is the build process actually running as UID 999? If you pass
‘--disable-chroot’, then I think build users are not used at all, right?
> From 0307646b22fc488e6342f5814fdef336dd154be3 Mon Sep 17 00:00:00 2001
> From: Manolis Ragkousis <manolis837@gmail.com>
> Date: Sun, 7 Aug 2016 17:48:30 +0300
> Subject: [PATCH 1/2] daemon: Break CHROOT_ENABLED into smaller macros.
>
> Checking for CLONE_NEWNS is only needed for using tha Linux specific clone(2),
> otherwise we can use fork(2).
>
> * nix/libstore/build.cc (CHROOT_ENABLED): Break into CHROOT_ENABLED
> and CLONE_ENABLED.
> (DerivationGoal::startBuilder): Replace CHROOT_ENABLED with CLONE_ENABLED.
> (DerivationGoal::runChild): Only define pivot_root() if SYS_pivot_root is
> defined.
[...]
> -#define CHROOT_ENABLED HAVE_CHROOT && HAVE_SYS_MOUNT_H && defined(MS_BIND) && defined(MS_PRIVATE) && defined(CLONE_NEWNS) && defined(SYS_pivot_root)
> +#define CHROOT_ENABLED HAVE_CHROOT && HAVE_SYS_MOUNT_H && defined(MS_BIND) && defined(MS_PRIVATE)
> +#define CLONE_ENABLED defined(CLONE_NEWNS)
> +
> +#if defined(SYS_pivot_root)
> +#define pivot_root(new_root, put_old) (syscall(SYS_pivot_root, new_root,put_old))
> +#endif
>
> #if CHROOT_ENABLED
> #include <sys/socket.h>
> @@ -2005,7 +2010,7 @@ void DerivationGoal::startBuilder()
> - The UTS namespace ensures that builders see a hostname of
> localhost rather than the actual hostname.
> */
> -#if CHROOT_ENABLED
> +#if CLONE_ENABLED
> if (useChroot) {
> char stack[32 * 1024];
> int flags = CLONE_NEWPID | CLONE_NEWNS | CLONE_NEWIPC | CLONE_NEWUTS | SIGCHLD;
I’m not sure this is correct. Perhaps we rather need an “#ifdef
__linux__” around the use of clone(2)?
Other options:
1. Implement clone(2) with CLONE_NEW* in libc on GNU/Hurd.
2. Add a “sandbox” abstraction in the daemon, with OS-specific
implementations of the abstraction (the Nix daemon did that at some
point, with the goal of supporting proprietary macOS etc.)
For GNU/Linux, it’d use chroot(2)+clone(NEWNS) etc. as root.
On GNU/Hurd, it could spawn the process in a sub-Hurd, i.e., with
its own proc server, root file system server, and without a pfinet
server running.
Option #2 can be fun to implement and probably easier and less
controversial than Option #1. However, it does mean adding more code of
the C++ code base, which is sad.
Either way, it’s a bit of work, so this can definitely come later.
Ludo’.
next prev parent reply other threads:[~2020-03-11 14:50 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200310075832.7126.86402@vcs0.savannah.gnu.org>
[not found] ` <20200310075845.291F421123@vcs0.savannah.gnu.org>
2020-03-10 8:54 ` 08/33: gnu: make: Revert to 4.1 for the Hurd Ludovic Courtès
2020-03-10 9:16 ` Jan Nieuwenhuizen
[not found] ` <20200310075844.240A021123@vcs0.savannah.gnu.org>
2020-03-10 8:55 ` 05/33: gnu: hurd: Fix hurd-target? Ludovic Courtès
2020-03-10 11:22 ` Jan Nieuwenhuizen
[not found] ` <20200310075846.1DA6821123@vcs0.savannah.gnu.org>
2020-03-10 9:02 ` 11/33: gnu: glibc: Add and update patches for the Hurd Ludovic Courtès
2020-03-10 11:28 ` Jan Nieuwenhuizen
[not found] ` <20200310075853.45FCC21252@vcs0.savannah.gnu.org>
2020-03-10 9:04 ` 33/33: daemon: Workaround issues " Ludovic Courtès
2020-03-10 12:54 ` Jan Nieuwenhuizen
2020-03-11 14:50 ` Ludovic Courtès [this message]
2020-03-12 6:59 ` Jan Nieuwenhuizen
2020-03-12 12:59 ` bug#40006: " Ludovic Courtès
2020-03-12 12:59 ` Ludovic Courtès
2020-03-12 6:59 ` bug#40006: " Jan Nieuwenhuizen
[not found] ` <20200310075847.6059A2112F@vcs0.savannah.gnu.org>
2020-03-10 9:06 ` 15/33: gnu: coreutils: Remove libcap dependency " Ludovic Courtès
2020-03-11 15:01 ` Jan Nieuwenhuizen
2020-03-11 18:09 ` Vincent Legoll
2020-03-11 19:43 ` Jan Nieuwenhuizen
2020-03-12 13:01 ` Ludovic Courtès
2020-03-14 8:28 ` Jan Nieuwenhuizen
2020-03-14 8:28 ` bug#40006: " Jan Nieuwenhuizen
[not found] ` <20200310075851.4497E2125F@vcs0.savannah.gnu.org>
2020-03-10 9:10 ` 27/33: gnu: commencement: glibc-intermediate: Build fixes " Ludovic Courtès
2020-03-10 12:45 ` Jan Nieuwenhuizen
[not found] ` <20200310075850.035F02125B@vcs0.savannah.gnu.org>
2020-03-10 9:13 ` 23/33: gnu: commencement: gcc-boot0: Build fix " Ludovic Courtès
2020-03-10 9:18 ` Efraim Flashner
2020-03-10 13:53 ` Jan Nieuwenhuizen
2020-03-11 14:27 ` Jan Nieuwenhuizen
2020-03-11 15:14 ` Efraim Flashner
2020-03-11 16:20 ` Jan Nieuwenhuizen
2020-03-11 16:27 ` Efraim Flashner
2020-03-12 7:02 ` Jan Nieuwenhuizen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87h7yvgd3h.fsf@gnu.org \
--to=ludo@gnu.org \
--cc=guix-devel@gnu.org \
--cc=janneke@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/guix.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.