How can I wrap ld-linux or execve into it?

How can I wrap ld-linux or execve into it?

[Farid Zakaria]

 Hi,

Not exactly sure if this is the best mailing list for this question,
please recommend me elsewhere if more appropriate.

I am looking to perform some functionality before the dynamic linker
(linux-ld/ld.so) is invoked.

My naive assessment was that I would be able to set in the PT_INTERP
section of a binary, my *static binary*, which will then execve into
the dynamic linker after doing some precanned actions.

I came across https://github.com/Mic92/nix-ld which seems to do
something similar, but I was curious why it has to do a lot more to
achieve the same effect with a jump.

Cheers
FZ

Re: How can I wrap ld-linux or execve into it?

[Jonathan Wakely]

On Mon, 31 Jan 2022, 03:54 Farid Zakaria via Gcc-help, <gcc-help@gcc.gnu.org>
wrote:

>  Hi,
>
> Not exactly sure if this is the best mailing list for this question,
> please recommend me elsewhere if more appropriate.
>
> I am looking to perform some functionality before the dynamic linker
> (linux-ld/ld.so) is invoked.
>

I would try the glibc list then.

Re: How can I wrap ld-linux or execve into it?

[Florian Weimer]

* Jonathan Wakely via Gcc-help:

> On Mon, 31 Jan 2022, 03:54 Farid Zakaria via Gcc-help, <gcc-help@gcc.gnu.org>
> wrote:
>
>>  Hi,
>>
>> Not exactly sure if this is the best mailing list for this question,
>> please recommend me elsewhere if more appropriate.
>>
>> I am looking to perform some functionality before the dynamic linker
>> (linux-ld/ld.so) is invoked.
>>
>
> I would try the glibc list then.

Specifically libc-help:

  <https://sourceware.org/mailman/listinfo/libc-help>

Farid, the LD_AUDIT interface may be what you are looking for.  It
allows one to write dynamic loader plugins which run very early.

Thanks,
Florian