Re: [RFC][PATCH v2 0/6] binutils patches to add DT_GNU_UNIQUE

[Michael Matz <matz@suse.de>]

Hello,

On Wed, 17 Jun 2020, Vivek Das Mohapatra via Gnu-gabi wrote:

> Hi - notifying this list (as requested) of a patchset to binutils-gdb,
> described below:
> 
> https://sourceware.org/pipermail/binutils/2020-June/111747.html

Can you describe the purpose and semantics of the new dynamic tag in 
textual form that doesn't refer to glibc functions and terms?  I.e. 
something that we can actually discuss on this mailing list?

Because the best description in the patch series seems to be what you 
quoted:

> > It adds a DT_GNU_UNIQUE dynamic section which is intended to mark
> > libraries which should implicitly be opened as if RTLD_SHARED
> > had been passed to dlmopen when the target namespace is not
> > LM_ID_BASE.

and that doesn't seem to be text we want to put into the GNU variant 
of the gABI, e.g. it talks about namespaces (no gABI concept) and dlmopen 
(also no gABI function).

I mean, we could just reserve value 0x6ffffdf4 with name DT_GNU_UNIQUE in 
the GNU/Linux gABI and be done.  But it seems saner to actually document 
the intended semantics of it at the same place where it's reserved.


Ciao,
Michael.