libselinux's __attribute__((constructor)) versus nVidia libGL.so

libselinux's __attribute__((constructor)) versus nVidia libGL.so

[Colin Walters]

Hi,

Can someone from the libselinux side comment on this bug?



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Re: libselinux's __attribute__((constructor)) versus nVidia libGL.so

[Colin Walters]

This bug:

https://bugzilla.gnome.org/show_bug.cgi?id=706836


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Re: libselinux's __attribute__((constructor)) versus nVidia libGL.so

[Daniel P. Berrange]

On Tue, Aug 27, 2013 at 01:47:54PM -0400, Colin Walters wrote:
> This bug:
> 
> https://bugzilla.gnome.org/show_bug.cgi?id=706836

FWIW, you can define "priority" values on the constructor attributes, to
sort out ordering between libraries, but this sucks as a general purpose
solution as it requires co-ordination of priorities between different a
projects. eg you might fix the selinux vs nvidia problem now, but it can
recur with any other library using constructors in the future. IMHO it
would be better to use pthread_once to do any one time initialization
of library code

Daniel
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Re: libselinux's __attribute__((constructor)) versus nVidia libGL.so

[Stephen Smalley]

On 08/28/2013 06:06 AM, Daniel P. Berrange wrote:
> On Tue, Aug 27, 2013 at 01:47:54PM -0400, Colin Walters wrote:
>> This bug:
>>
>> https://bugzilla.gnome.org/show_bug.cgi?id=706836
> 
> FWIW, you can define "priority" values on the constructor attributes, to
> sort out ordering between libraries, but this sucks as a general purpose
> solution as it requires co-ordination of priorities between different a
> projects. eg you might fix the selinux vs nvidia problem now, but it can
> recur with any other library using constructors in the future. IMHO it
> would be better to use pthread_once to do any one time initialization
> of library code

I think we considered switching that constructor over to using
pthread_once (as we already do for many other forms of initialization
via the selinux_once macro), but it would require inserting such calls
into many/most of the libselinux functions prior to any use of
selinux_mnt or selinux_page_size.  Certainly doable (and willing to
accept such a patch), but I guess the question is whether it is worth it
or if nvidia should just fix their library.



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