GNU bug report logs - #20437
ls links too many dynamic libraries

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: bug-coreutils <at> gnu.org
Subject: ls links too many dynamic libraries
Date: Sun, 26 Apr 2015 22:30:16 -0700

[Message part 1 (text/plain, inline)]

Currently GNU 'ls' dynamically links a whole bunch of libraries, libraries like 
libpcre and liblzma.  Can we figure out some way to remove the runtime 
dependencies on these libraries?  It's better if a core utility like 'ls' avoids 
libthis and libthat unless the libraries are vital to its function, which these 
shouldn't be.

I installed the attached patches to get rid of one unnecessary library, libacl, 
on GNU/Linux.  Can we do better and get rid of more dependencies?  Perhaps using 
techniques similar to what was used to get rid of libacl?

[0001-build-update-gnulib-submodule-to-latest.patch (text/x-patch, attachment)]

[0002-ls-on-GNU-Linux-remove-dependency-on-libacl.patch (text/x-patch, attachment)]

Message #8 received at 20437 <at> debbugs.gnu.org (full text, mbox):

From: Bernhard Voelker <mail <at> bernhard-voelker.de>
To: Paul Eggert <eggert <at> cs.ucla.edu>, 20437 <at> debbugs.gnu.org
Subject: Re: bug#20437: ls links too many dynamic libraries
Date: Mon, 27 Apr 2015 08:40:13 +0200

On 04/27/2015 07:30 AM, Paul Eggert wrote:
> --- a/bootstrap.conf
> +++ b/bootstrap.conf

...

> @@ -318,9 +319,9 @@ gnulib_tool_option_extras="--tests-base=gnulib-tests --with-tests --symlink\
>  buildreq="\
>  autoconf   2.64
>  automake   1.11.2
> -autopoint  -
> +autopoint  0.19.4
>  bison      -
> -gettext    0.18.1
> +gettext    0.19.4
>  git        1.4.4
>  gperf      -
>  gzip       -

This gnulib update seems to bump the prerequisites for building
coreutils quite high - at least on a current openSUSE-13.2 system
building now fails:

./bootstrap
./bootstrap: Error: 'autopoint' version == 0.19.2 is too old
./bootstrap:        'autopoint' version >= 0.19.4 is required
./bootstrap: Error: 'gettext' version == 0.19.2 is too old
./bootstrap:        'gettext' version >= 0.19.4 is required

I know that we tend to use the newest gear, but IIRC from last time
we agreed on supporting at least the latest stable version of the
bigger distros to ease providing patches for regular (advanced) users.
What especially does gnulib need from 0.19.4?  Could we work around
it?

Thanks & have a nice day,
Berny

Message #11 received at 20437 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Bernhard Voelker <mail <at> bernhard-voelker.de>, 20437 <at> debbugs.gnu.org
Subject: Re: bug#20437: ls links too many dynamic libraries
Date: Mon, 27 Apr 2015 00:27:21 -0700

Bernhard Voelker wrote:
> Could we work around
> it?

Sure, how about if we shrink it down to 0.19?  Would that work for you?

I picked 0.19.4 only because the old value was too low for gnulib and I was at 
0.19.4.  I think it needs to be at least 0.19, because of the recent gnulib changes.

Message #14 received at 20437 <at> debbugs.gnu.org (full text, mbox):

From: Bernhard Voelker <mail <at> bernhard-voelker.de>
To: Paul Eggert <eggert <at> cs.ucla.edu>, 20437 <at> debbugs.gnu.org
Subject: Re: bug#20437: ls links too many dynamic libraries
Date: Mon, 27 Apr 2015 11:55:22 +0200

On 04/27/2015 09:27 AM, Paul Eggert wrote:
> Bernhard Voelker wrote:
>> Could we work around
>> it?
>
> Sure, how about if we shrink it down to 0.19?  Would that work for you?

yes, "0.19" is okay for me - openSUSE-13.2 has 0.19.2.

Thanks & have a nice day,
Berny

Message #17 received at 20437 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Paul Eggert <eggert <at> cs.ucla.edu>, 20437 <at> debbugs.gnu.org
Subject: Re: bug#20437: ls links too many dynamic libraries
Date: Mon, 27 Apr 2015 14:12:23 +0100

[Message part 1 (text/plain, inline)]

tag 20437 notabug
close 20437
stop

On 27/04/15 06:30, Paul Eggert wrote:
> Currently GNU 'ls' dynamically links a whole bunch of libraries, libraries like 
> libpcre and liblzma.  Can we figure out some way to remove the runtime 
> dependencies on these libraries?  It's better if a core utility like 'ls' avoids 
> libthis and libthat unless the libraries are vital to its function, which these 
> shouldn't be.
> 
> I installed the attached patches to get rid of one unnecessary library, libacl, 
> on GNU/Linux.  Can we do better and get rid of more dependencies?  Perhaps using 
> techniques similar to what was used to get rid of libacl?

As was discussed recently¹ with removing the libmount dependency for df,
these dependencies are coming from libselinux, and one of the primary
authors of libselinux was made aware of that issue, so I'm closing
this here.

coreutils linking with libselinux are:

 chcon cp dir install id ls mkdir mkfifo mknod mv runcon stat vdir

BTW I noticed ldd -v doesn't give complete info,
and that `readelf -d $(which ls) | grep NEEDED` is better.
This is wrapped in the lddot² visualizer, and I've attached
the output from `lddot git/coreutils/src/ls | graph-easy --as png`

cheers,
Pádraig.

¹ http://lists.gnu.org/archive/html/coreutils/2015-04/msg00011.html
² http://jwilk.net/software/lddot

[ls-shared-libs.png (image/png, attachment)]

Message #24 received at 20437 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: Paul Eggert <eggert <at> cs.ucla.edu>, 20437 <at> debbugs.gnu.org
Cc: SE-Linux <SELinux <at> tycho.nsa.gov>
Subject: Re: bug#20437: ls links too many dynamic libraries
Date: Mon, 27 Apr 2015 15:02:35 +0100

On 27/04/15 14:12, Pádraig Brady wrote:
> tag 20437 notabug
> close 20437
> stop
> 
> On 27/04/15 06:30, Paul Eggert wrote:
>> Currently GNU 'ls' dynamically links a whole bunch of libraries, libraries like 
>> libpcre and liblzma.  Can we figure out some way to remove the runtime 
>> dependencies on these libraries?  It's better if a core utility like 'ls' avoids 
>> libthis and libthat unless the libraries are vital to its function, which these 
>> shouldn't be.
>>
>> I installed the attached patches to get rid of one unnecessary library, libacl, 
>> on GNU/Linux.  Can we do better and get rid of more dependencies?  Perhaps using 
>> techniques similar to what was used to get rid of libacl?
> 
> As was discussed recently¹ with removing the libmount dependency for df,
> these dependencies are coming from libselinux, and one of the primary
> authors of libselinux was made aware of that issue, so I'm closing
> this here.
> 
> coreutils linking with libselinux are:
> 
>  chcon cp dir install id ls mkdir mkfifo mknod mv runcon stat vdir
> 
> BTW I noticed ldd -v doesn't give complete info,
> and that `readelf -d $(which ls) | grep NEEDED` is better.
> This is wrapped in the lddot² visualizer, and I've attached
> the output from `lddot git/coreutils/src/ls | graph-easy --as png`
> 
> cheers,
> Pádraig.
> 
> ¹ http://lists.gnu.org/archive/html/coreutils/2015-04/msg00011.html
> ² http://jwilk.net/software/lddot

BTW I had a look at whether we could duplicate some getfilecon() logic
internally, but it doesn't seem practical due to mcstransd which
is a daemon that's used to translate the MCS / MLS internal policy
levels into user friendly labels.

I.E. we could duplicate the logic, and remove the lzma and pcre dependencies,
but it seems like too much to be duplicating. Further reductions in deps
might be possible by splitting up libselinux, allowing apps like ls
that just read contexts, to link with the appropriate lib.

cheers,
Pádraig.

Message #27 received at 20437 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Pádraig Brady <P <at> draigBrady.com>, 20437 <at> debbugs.gnu.org
Cc: SE-Linux <SELinux <at> tycho.nsa.gov>
Subject: Re: bug#20437: ls links too many dynamic libraries
Date: Mon, 27 Apr 2015 08:21:06 -0700

Pádraig Brady wrote:
> Further reductions in deps
> might be possible by splitting up libselinux, allowing apps like ls
> that just read contexts, to link with the appropriate lib.

I tried to see how to send a copy of this bug <http://bugs.gnu.org/20437> to the 
libselinux developers, but the libselinux source distribution doesn't mention 
any way to file bug reports (!).  (So now I guess I have *two* bug reports to 
send them. :-)  Who maintains libselinux and how does one file and track a bug 
report about libselinux?

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