Re: [PATCH v9 0/13] implement dlmem() function

[stsp <stsp2@yandex.ru>]

Hi Adhemerval, thanks for a follow-up!

29.03.2023 17:32, Adhemerval Zanella Netto пишет:
> This discussion has been dragging without much conclusion while you 
> have sent
> multiple iterations of the same proposal without addressing the initial issues
> Carlos, Jonathan, and myself have raised.
>
> I will not focus on your specific usercase since it is quite singular and I
> think will not be applicable to a libc interface (mapping a VM memory with
> different bit size and gluing all together should be an application domain
> instead of bleeding out the interface to the libc).

Yes, which is why I am trying to put in
the "widely" requested in the past dlmem()
function, which is quite agnostic to my use-case
but allows me to accomplish the task.


> Jonathan already summarized the main issue with dlmem:
>
>    - dlmem() seems to to expect the user to parse the program headers and mmap()
>    the binary as required. That requires the application to re-implement a core,
>    delicate piece of ld.so... and do so correctly. From an API design perspective,
>    that seems like a very poor choice of abstraction.
>
> As well Carlos:
>
>    * No guarantee that the memory that is loaded meets the preconditions for the
>    dynamic loader and application uses.
>
> And this alone seems to me that this interface is not easily composable and

OK, yes, I've heard all of you, but what
should I do? I can SWEAR that my test-cases
do not parse the elf headers. I can swear
that I have no idea what are you talking about.
Well, I did that already, but nothing helps. :(
So how should I proceed with the claim that
was said by everyone, and yet never confirmed
by a single fact?
I do not parse any elf headers, maybe glibc does,
I do not! If this is wrong, please point me
IN MY TEST-CASES that I actually do this.

> adds a lot of corner cases if the user does not provide an expected ELF image.
> This is in par of what Carlos has raised [1] and IMHO you have not addresses the
> issues, since you have focused on how this interface applies to your specific
> problem instead of see who it fits as a generic libc interface (I will let
> Carlos comment further).

I have not addressed that issue, I have
not seen that issue, I don't believe this
issue even exist.
What should I do?
Please, be constructive.
You can point it to me IF it is there.

> So I don't think dlmem really fits on glibc, although I might take a loot
> on the internal code refactoring. I am ccing Rich Felker, creator of musl
> libc, since he might have some additional insights whether this interface
> make sense or not (and he usually have good ones).
Thanks!
I appreciate the involvement of Rich Felker,
or any other activity to bring that discussion
further. But we need to get off the aforementioned
question around the elf headers.

Also please note that I have a v10 locally with
some fixes and new test-cases, so v9 should
not be reviewed quite literally.