[Xenomai] Won`t build on new Debian Stable

Norbert Lange nolange79 at gmail.com
Fri Oct 13 10:38:26 CEST 2017


Second attempt at fixing it, you could surely make this more complex
using autohell but I am not going there.

If I understood correctly this script is only necessary if the
application is linked -static?
Means I would try to avoid using it, aslong I dont explicitly want to do that.

Kind regards,
Norbert

2017-10-13 9:40 GMT+02:00 Norbert Lange <nolange79 at gmail.com>:
> Ok I just realized there is a "-Ur" option, aside from "-U -r".
>
> You get alot otherwise undocumented flags with "gcc --help -v" BTW
>
> 2017-10-13 9:13 GMT+02:00 Norbert Lange <nolange79 at gmail.com>:
>> Hello,
>>
>> I tracked down the source of information to this:
>> https://wiki.ubuntu.com/SecurityTeam/PIE
>>
>> I changed the flags from "-Wl,-Ur" to "-Wl,-U -r", so you wont get an
>> explanation from me, why -U has to be passed for the linker.
>> And by the way, gcc accepts -U aswell, so this might be preferable to
>> be used directly too.
>>
>> I don`t know why those flags aren' t documented, bug in gcc
>> documentation? As far as I understand is that gcc is smart enough to
>> correctly deal with the flags gcc directly received, but the linker
>> lacks that information.
>>
>> I don' t know what the issue is with the C++ Constructors, in the
>> context of this change?
>> (I heard about the issues if those reside in a shared library, use
>> function from libcobald and don't depend on libcobald. Which is more
>> of a broken build to me if you don't add the depended libs, and will
>> bite you the same way if you use GCCs constructor attribute)
>>
>> Kind regards,
>> Norbert.
>>
>> 2017-10-12 10:33 GMT+02:00 Henning Schild <henning.schild at siemens.com>:
>>> Hey Norbert,
>>>
>>> thanks for looking into that again! Could you please explain how and
>>> why that works, or point out what to look at in flint? Mailing list
>>> thread, commit, something like that.
>>>
>>> As far as i can see gcc now gets a "-r" which i do not find in the
>>> manpage. And ld gets a "-U" which i do not find in its manpage. And
>>> there is something about c++ constructors which might change the
>>> behaviour of xenomai.
>>>
>>> Henning
>>>
>>> Am Tue, 10 Oct 2017 16:38:50 +0200
>>> schrieb Norbert Lange <nolange79 at gmail.com>:
>>>
>>>> Some highly trivial fix attached!
>>>> Its strange that this flag is not documented in the manual (I found
>>>> out abaout this fix from https://launchpad.net/ubuntu/+source/flint)
>>>>
>>>> Norbert Lange
>>>>
>>>> 2017-08-10 11:49 GMT+02:00 Henning Schild
>>>> <henning.schild at siemens.com>:
>>>> > Hi Norbert,
>>>> >
>>>> > Thanks! In fact that issue has come up before and a similar
>>>> > workaround was described. It should be fixed, patches welcome!
>>>> >
>>>> > Henning
>>>> >
>>>> > Am Wed, 9 Aug 2017 16:21:02 +0200
>>>> > schrieb Norbert Lange <nolange79 at gmail.com>:
>>>> >
>>>> >> Hello,
>>>> >>
>>>> >> Building the xenomai package won`t work because debian now
>>>> >> defaults to using pie, and the linker will complain with "ld: -r
>>>> >> and -pie may not be used together"
>>>> >>
>>>> >> A workaround for now is to add the flags manually:
>>>> >> ../xenomai-3.0.5/configure LDFLAGS=-no-pie CFLAGS="-fno-PIE
>>>> >> -fno-pie -no-pie"
>>>> >>
>>>> >> A real fix would be similar to
>>>> >> http://lists.gnu.org/archive/html/bug-grub/2016-11/msg00011.html
>>>> >> (no-pie is not supported on old and other compilers)
>>>> >>
>>>> >> Kind regards,
>>>> >> Norbert
>>>> >>
>>>> >> _______________________________________________
>>>> >> Xenomai mailing list
>>>> >> Xenomai at xenomai.org
>>>> >> https://xenomai.org/mailman/listinfo/xenomai
>>>> >
>>>
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