Re: [PATCH] e2fsprogs: add packageconfig for -file-

[Randy MacLeod <randy.macleod@windriver.com>]

On 2016-09-18 10:37 PM, Christopher Larson wrote:
>
> On Sun, Sep 18, 2016 at 7:32 PM, Randy MacLeod
> <randy.macleod@windriver.com <mailto:randy.macleod@windriver.com>> wrote:
>
>     On 2016-09-17 01:09 AM, Christopher Larson wrote:
>
>
>         On Fri, Sep 16, 2016 at 6:37 PM, Randy MacLeod
>         <Randy.MacLeod@windriver.com
>         <mailto:Randy.MacLeod@windriver.com>
>         <mailto:Randy.MacLeod@windriver.com
>         <mailto:Randy.MacLeod@windriver.com>>> wrote:
>
>             Without a packageconfig dependency for the file utility, there's
>             a very rare compile faiure caused by a race where the magic.h
>             header file is not found:
>
>              ../../../git/lib/support/plausible.c:33:19: fatal error:
>         magic.h:
>             No such file or directory
>
>             This file, plausible.c, is part of libsupport.a which is used by
>             many binaries produced by the e2fsprogs package. plausible.c
>         attempts
>             to dynamically load libmagic.so if the e2fsprogs configure
>         detects
>             that magic was available. Adding the packageconfig will
>         eliminate
>             the build as well as the possible configure-time race condition.
>
>             Signed-off-by: Randy MacLeod <Randy.MacLeod@windriver.com
>         <mailto:Randy.MacLeod@windriver.com>
>             <mailto:Randy.MacLeod@windriver.com
>         <mailto:Randy.MacLeod@windriver.com>>>
>             ---
>              meta/recipes-devtools/e2fsprogs/e2fsprogs_1.43.bb
>         <http://e2fsprogs_1.43.bb>
>             <http://e2fsprogs_1.43.bb> | 1 +
>              1 file changed, 1 insertion(+)
>
>             diff --git
>         a/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.43.bb
>         <http://e2fsprogs_1.43.bb>
>             <http://e2fsprogs_1.43.bb>
>             b/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.43.bb
>         <http://e2fsprogs_1.43.bb>
>             <http://e2fsprogs_1.43.bb>
>             index f4855bc..1707cb9 100644
>             --- a/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.43.bb
>         <http://e2fsprogs_1.43.bb>
>             <http://e2fsprogs_1.43.bb>
>             +++ b/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.43.bb
>         <http://e2fsprogs_1.43.bb>
>             <http://e2fsprogs_1.43.bb>
>             @@ -23,6 +23,7 @@ EXTRA_OECONF += "--libdir=${base_libdir}
>             --sbindir=${base_sbindir} \
>              EXTRA_OECONF_darwin = "--libdir=${base_libdir}
>             --sbindir=${base_sbindir} --enable-bsd-shlibs"
>
>              PACKAGECONFIG ??= ""
>             +PACKAGECONFIG[file] = ',,file'
>
>
>         This isn’t going to be good enough. You aren’t explicitly
>         enabling/disabling the option, so it’ll still detect based on
>         what’s in
>         the sysroot, so recipe build order will result in non-deterministic
>         behavior.
>
>
>     Hi Christopher,
>
>     Thanks for the response but I don't understand.
>     I'm probably wrong so please explain.
>     It seems that you're suggesting that I add:
>      --with[out]-magic to e2fsprogs configure, and while
>     I could do that, it does not seem to be needed.
>
>
>     Short response:
>
>       This change forces 'file' to be built before e2fsprogs if 'file'
>       is present in the image or world build. Then e2fsprogs will
>       detect magic.h,libmagic.so and  the race is eliminated.
>
>
> That’s only the case if ‘file’ is in PACKAGECONFIG, if not, it’ll still
> behave the way it did before, and change its deps based on build order.
> Our policy is to avoid floating deps period, regardless of
> PACKAGECONFIG. If a given packageconfig is not enabled, then explicitly
> disable the dependency, don’t detect and use it anyway.

Ah right and now I see some uses where there would not be a
package dependency required.

I'll likely send a v2 adding just:
    PACKAGECONFIG ??= "file"
since 'fuse' is in the meta-filesystems layer but
I don't understand how the fuse dependency gets fixed since
it's not changed in meta-oe/meta-filesystems AFAIKT. Should the
fuse dependency be added as well so that builds that add
the meta-filesystems layer don't have this potential race?
I could do some testing to find out but it's late here.
Robert likely knows all about this so I'm
CCing him since he also committed the fuse change.

It seems unlikely but we could have a pile of clean-up
to do...

Thanks,
../Randy

> --
> Christopher Larson
> clarson at kergoth dot com
> Founder - BitBake, OpenEmbedded, OpenZaurus
> Maintainer - Tslib
> Senior Software Engineer, Mentor Graphics


-- 
# Randy MacLeod. SMTS, Linux, Wind River
Direct: 613.963.1350 | 350 Terry Fox Drive, Suite 200, Ottawa, ON, 
Canada, K2K 2W5