Re: [musl] Re: OS detection wrong on Alpine Linux 3.10

[Ariadne Conill <ariadne@dereferenced.org>]

Hello,

On 2020-09-23 10:16, Jeffrey Walton wrote:
> On Wed, Sep 23, 2020 at 12:08 PM Rich Felker <dalias@libc.org> wrote:
>>
>> On Wed, Sep 23, 2020 at 09:13:16AM -0400, James Y Knight wrote:
>>>>
>>>>> All I need to know is what version of Musl I am dealing with and I can
>>>>> configure myself.
>>>>
>>>>    Are you willing to maintain an #ifdef forest for all the versions of
>>>> all the libcs and all the kernels your programs may be used with, so
>>>> you can list exhaustively the available features in every configuration?
>>>
>>> At the risk of jumping in on a question asked of someone else: yes,
>>> absolutely! (Not _all_ available features of course, just the ones
>>> required.)
>>>
>>> There are generally not that many nonstandard features you'd want to use in
>>> a typical program, and using an ifdef forest to implement an abstraction
>>> layer around those couple items is just fine.
>>
>> I can't know whether you're "willing", but you're definitely not
>> willing and able. "All the..." includes people's personal projects
>> (from scratch or patches to existing ones) that you will never see,
>> future systems that come into existence long past your involvement in
>> the project or even your lifetime, etc.
> 
> Unless something has changed recently, Botan, Crypto++ and OpenSSL are
> still being carried by most Linux distributions. OpenSSL is also
> regularly distributed as part of other OSes, like AIX, Android, BSDs,
> iOS, OS X and Solaris.
> 
> And unlike some other projects,[1] Botan, Crypto++ and OpenSSL
> actually work in practice on all the platforms without a configuration
> program that performs feature tests.

You are dead wrong on this topic.  OpenSSL actually goes the other way 
and performs absolutely wacky tests like "are we running on big-endian 
amd64."  Any cryptography library is going to have to perform feature 
tests (either at build time or run time) to determine whether features 
like hardware acceleration are possible.

> [1] the Rust compiler comes to mind here. It works on Linux x86_64,
> but it's hit or miss whether it works or not on other architectures
> like ARMv7, Aarch64 and PowerPC, even after an approved configuration
> program is run.

Cargo is capable of doing build-time configuration tests.  If a crate 
fails to properly run tests, it is not because the Rust ecosystem works 
as you believe it does.

Ariadne