Re: Removing glibc from the musl .2 ABI

["A. Wilcox" <awilfox@adelielinux.org>]

[-- Attachment #1.1: Type: text/plain, Size: 2631 bytes --]

On 07/17/19 10:11, Rich Felker wrote:
> On Wed, Jul 17, 2019 at 08:13:44AM -0500, A. Wilcox wrote:
>> On 07/16/19 22:37, Rich Felker wrote:
>>> On Thu, Jul 11, 2019 at 06:58:38PM -0500, A. Wilcox wrote:
>>>> (Full disclosure: I am the principal author of gcompat.)
>>>>
>>>> Hi,
>>>>
>>>> Now that gcompat has matured, I was wondering if perhaps musl should
>>>> consider dropping the glibc ABI guarantees when the "2 ABI" lands.
>>>>
>>>> This would make the LFS64 symbol mess completely moot.
>>>
>>> This is separate from the .2 ABI topic, but what would you think about
>>> removing glibc ABI-compat from the current .1 ABI and replacing it
>>> with enhanced gcompat? I was thinking ldso could load libgcompat
>>> instead of returning a reference to itself for DT_NEEDED referencing
>>> libc.so.6, and we could move all ABI-compat symbols into gcompat.
>>>
>>> The reason I bring it up is that ripping out the LFS64
>>> unwantedly-linkable stuff while keeping it as ABI-only is looking like
>>> more of a pain than I expected.
>>
>> We would be more than happy to work with you on that.
>>
>> Would gcompat then become a runtime requirement for glibc apps on musl?
>> What would musl do if gcompat isn't installed on a system?
> 
> It would just be a failed DT_NEEDED.


Okay, sounds reasonable.


>> What about
>> things like libm and libdl, which I've seen some apps force DT_NEEDED
>> anyway when built against musl?
> 
> These could still be ignored (mapped to internal libc) since any
> program using them would also necessarily be using libc.so.6.


Likewise.


>> Just trying to make sure the community has a clear view of what this
>> looks like before we jump in.
> 
> Yes. This isn't a request to jump in, just looking at feasability and
> whether there'd be interest from your side. Being that ABI-compat
> doesn't actually work very well without gcompat right now, though, I
> think it might make sense. I'll continue to look at whether there are
> other options, possibly just transitional, that might be good too.


I meant: I want a clear view of the boundaries between musl and gcompat,
before we (Adélie / the gcompat team) jump in and start designing how we
want to handle all the new symbols we may end up with :)

We also were considering setting up a dedicated gcompat site so that the
community could share apps that are known to work / fail, symbol
presence, LSB missing symbols, etc.  Would that be of interest from your
side as well?

Best,
--arw

-- 
A. Wilcox (awilfox)
Project Lead, Adélie Linux
https://www.adelielinux.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 833 bytes --]