[Buildroot] [Bug 11366] New: [2018.08] SysV IPC not available for fakeroot on WSL

[Buildroot] [Bug 11366] New: [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

            Bug ID: 11366
           Summary: [2018.08] SysV IPC not available for fakeroot on WSL
           Product: buildroot
           Version: unspecified
          Hardware: PC
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P5
         Component: Other
          Assignee: unassigned at buildroot.uclibc.org
          Reporter: jfdoyon at gmail.com
                CC: buildroot at uclibc.org
  Target Milestone: ---

When using Ubuntu on Windows Susbsystem for Linux (WSL) as your host build
environment, the process fails on the execution of "fakeroot", with an error
message to the effect that "fakeroot has failed due to SysV IPC not being
available".

This is indeed correct, as the WSL system doesn't have the functionality.

A WSL bug has been filed: https://github.com/Microsoft/WSL/issues/2465

The workaround is to copy/link the host /usr/bin/fakeroot-tcp into the builroot
host output, and re-run, it then succeeds no problem.

Suggestion: detect availability of SysV IPC and/or TCP, and build/use the
appropriate fakeroot. If the host doesn't have either facility available, warn
early (instead of finding out at the very end of a possibly long compilation
run).

Thanks,
J.F.

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

--- Comment #1 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
Thanks for the bug report. I'd say this is something that should be improved in
fakeroot configure script itself: it should detect if SysV IPC is available or
not, and fallback to TCP if not.

Is this something you could have a look at ?

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

--- Comment #2 from J.F. <jfdoyon@gmail.com> ---
I'll give it a try!

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

--- Comment #3 from J.F. <jfdoyon@gmail.com> ---
findings so far:

OK, so WSL does have some SysV IPC, but no message Q's, which is the feature
needed by fakeroot/faked by default.

The cleanest way to test this appears to be to use the ipcmk utility provided
by the host util-linux package ... only if the user selects the host util
package in his config however.  If ipcmk -Q returns 1, use TCP.

Also, the fakeroot package builds sysv OR tcp. In order to support both, you
run 2 builds, presumably configured as two packages. Ideally, you would build
only one, based on the availability opf message Qs, if at all possible.

So one option is to force the host-util-linux package with most programs (force
the relevant BR2 option on, or mor eprecisely, remove the option and always
have it on), and then re-package 2 fakeroots and then use ipcmk at run time to
select the right fakeroot.

Another might be to simply give users the ability to select "TCP Fakeroot" in
their config via a BR2 variable. Since this is an edge case, it seems it might
be simpler to just do it that way, not unlike the way the host OpenSSL and
libelf requirements exist for the kernel.

Since this dependency is on a kernel system call, there's no clean way to
simply patch the existing fakeroot package and configure script ONLY, as Thomas
suggested. Maybe I could patch the configure script to use ipcmk however ... ?
I know *nothing* about how to work with autoconf however :P Because normally
you would build this tool as part of a distro on a separate host, dynamic
detection of IPC Message Q's would be of limited value "upstream" to the
fakeroot developers anyways ...

I think i would tend towards providing a user selectable config for "TCP
fakeroot" as a my favourite solution.

Thoughts?

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

--- Comment #4 from J.F. <jfdoyon@gmail.com> ---
Wait, I lied you can write custom tests in autoconf to test the actual presence
of a function ... I can see whether I can get a handle on that ... although a
user option still seems much simpler :)

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

--- Comment #5 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
Please don't use ipcmk, as requiring to build host-util-linux is clearly not
nice.

Instead, we want a simple test program in C, that will be compiled/executed by
fakeroot configure.ac script, to decide whether SysV message queues or TCP
should be used. You can use autoconf AC_TRY_RUN() to achieve this.

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

--- Comment #6 from J.F. <jfdoyon@gmail.com> ---
Created attachment 7791
  --> https://bugs.busybox.net/attachment.cgi?id=7791&action=edit
Proposed patch for configure.ac

Add a check to the configure script to test whether SysV IPC message queues are
actually functional. Fall back to TCP if not.

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

--- Comment #7 from J.F. <jfdoyon@gmail.com> ---
Created attachment 7796
  --> https://bugs.busybox.net/attachment.cgi?id=7796&action=edit
New fakeroot makefile

The new fakeroot makefile, which handles running autoreconf to re-generate the
configure script after patch 0003 has been applied.

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

--- Comment #8 from J.F. <jfdoyon@gmail.com> ---
See recently attached files.

This will need to be tested on a normally functioning linux host with SysV IPC
Message Q's running. Notably, use ipcs to make sure the message Q is cleaned up
properly after the test. The code is there and quite simple, but I can't test
it.

Also, the autoreconf setup is a little out of the ordinary, due to some
out-of-the ordinary libtool requirements by fakeroot it seems.

This now works cleanly on current Ubuntu for WSL.

Let me know if you have more suggestions for improvements?

Cheers,
J.F.

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

J.F. <jfdoyon@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at buildroot.uclibc |jfdoyon at gmail.com
                   |.org                        |

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

J.F. <jfdoyon@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

J.F. <jfdoyon@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Attachment #7796|0                           |1
        is obsolete|                            |

--- Comment #9 from J.F. <jfdoyon@gmail.com> ---
Created attachment 7801
  --> https://bugs.busybox.net/attachment.cgi?id=7801&action=edit
Improved fakeroot makefile

Improved makefile, added some missing package dependencies.

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

Thomas Petazzoni <thomas.petazzoni@free-electrons.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|jfdoyon at gmail.com           |yann.morin.1998 at free.fr

--- Comment #10 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
J.F, could you send a proper Buildroot patch on the mailing list, which
includes the fakeroot source code changes and the fakeroot.mk changes, all with
a proper description ?

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

--- Comment #11 from Peter Korsgaard <jacmet@uclibc.org> ---
Or even better, send the patch to upstream fakeroot and get it included there

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[Buildroot] [Bug 11366] [2018.08] SysV IPC not available for fakeroot on WSL

[bugzilla at busybox.net]

https://bugs.busybox.net/show_bug.cgi?id=11366

Peter Korsgaard <jacmet@uclibc.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #12 from Peter Korsgaard <jacmet@uclibc.org> ---
Fixed by:
https://git.buildroot.org/buildroot/commit/?id=fd1bcce9894773d7e1c1ca5be0f04b0b32128a1d

commit fd1bcce9894773d7e1c1ca5be0f04b0b32128a1d
Author: Matt Weber <matthew.weber@rockwellcollins.com>
Date:   Mon Sep 16 22:58:14 2019 -0500

    package/fakeroot: test for SYSV IPC support

    fakeroot can be built to either use SYSV IPC or TCP for message passing.

    A bug was discovered where Microsoft Windows 10 Services for Linux
    doesn't include support for SYSV IPC MsgQ.  This patch adds support to
    detect this case and automatically build fakeroot to use the TCP
    transport instead (It is assumed a TCP transport would definitely have
    more overhead then MsgQs so the default wasn't changed to TCP).

    Fixes
    https://bugs.busybox.net/show_bug.cgi?id=11366

    Cc: Yann E. MORIN <yann.morin.1998@free.fr>
    Signed-off-by: Jean-Francois Doyon <jfdoyon@gmail.com>
    Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
    [Arnout: use a post-patch hook and AUTORECONF=YES]
    Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

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