[yocto] prelink-cross with -fno-plt

[Shane Peelar]

Any of them on the system pretty much, and yes they are also built with
-fno-plt.

On Thu, May 23, 2019 at 9:59 PM Khem Raj <raj.khem at gmail.com> wrote:

>
>
> On 5/23/19 8:05 AM, Shane Peelar wrote:
> > Hi Everyone @ the Yocto project,
> >
> > I'm Shane Peelar, a PhD Candidate at the University of Windsor.
> > I'm writing to you about prelink-cross, as part of the Yocto project.
> > Specifically, I'm looking at using it with executables built using
> > `-fno-plt` under GCC.
> > I wasn't quite sure where to send this email to, so I figured I'd try
> > here.  If there's a better place to send this, please let me know.
> >
> > Right now, prelink-cross seems to fail an assertion in arch-x86_64.c,
> > line 421, when
> > using it with an executable built with `-fno-plt`:
> >
> > ...
> > assert (i < dso->ehdr.e_shnum)
> > ...
> >
> > This snippet seems to be looking for the ".plt" section and, since it
> > can't find it, the assertion fires.  This makes sense because in
> > `-fno-plt` executables, the `.plt` section is missing entirely.
> > I'm not an expert on ELF stuff, although I am learning quickly.  It
> > looks like
> > this code wants to write into GOT[1] the address of ".plt" + 0x16 --
> > since ".plt" doesn't
> > exist, does it make sense to just change this assert to an if statement
> > like so:
> >
> > ...
> >        if (i < dso->ehdr.e_shnum)
> >        { ... }
> > ...
> >
> > and skip over that part?  Or is this a real error condition for
> > prelink-cross and it really should not continue?  The executable in
> > question is also non-PIE, if that makes a difference.
> >
>
> what shared libs is this linking to ? are they also built with -fno-plt ?
>
> > Thanks for your time,
> > Shane
> >
>
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