openssh unix dev - Feb 2022 - detecting musl (was Re: Call for testing: OpenSSH 8.9)

Thorsten Glaser wrote in
 <dcc7333-54da-3e2-5ea7-3bcae4adf1f at tarent.de>:
 |On Fri, 18 Feb 2022, Steffen Nurpmeso wrote:
 |
 |>|Ouch, completely bogus.
 |> 
 |> It is a nice hint imho.
 |
 |Nope. It hardcodes a path into the *host* system. Absolutely wrong,
 |on multiple counts. (It would also trigger, say, on a glibc system
 |with musl installed.)

Well it may look secondarily.  This is musl libc in the end.
And note it does not, as per the snippet you removed, perform any
action on its own, it just gives a hint for a specific configure
option which does.  I am using the same mechanism (i have not
invented it) in my ~/.profile, for setting LC_ALL.

 |> That .. does not seem to be true for native musl systems?
 |
 |Link statically.

Nah.  For hello world you mean?  Well despite Theo de Raadt
ranting (as its -static) .. requires special or at least
non-standardized flags itself.
On AlpineLinux there is no static musl, and never has been in the
past seven years i use it.  But wait, i track musl for almost as
long, too:

  #?0|kent:musl.git$ git grep -i LOCPA master
  master:WHATSNEW:- MUSL_LOCPATH search was broken with multiple components
  master:src/locale/locale_map.c: if (!libc.secure) path =
getenv("MUSL_LOCPATH");

Never heard of it.

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)

(retopiccing and trimming Cc)

On Fri, 18 Feb 2022, Steffen Nurpmeso wrote:
> Well it may look secondarily.  This is musl libc in the end.
> And note it does not, as per the snippet you removed, perform any
> action on its own, it just gives a hint for a specific configure
> option which does.
I don?t understand what you are trying to say here.
>  |>|Ouch, completely bogus.
>  |> 
>  |> It is a nice hint imho.
>  |
>  |Nope. It hardcodes a path into the *host* system. Absolutely wrong,
>  |on multiple counts. (It would also trigger, say, on a glibc system
>  |with musl installed.)
>  I am using the same mechanism (i have not
> invented it) in my ~/.profile, for setting LC_ALL.
It?s plain wrong, that?s what it is.

lrwxrwxrwx 1 root root 25  2. Okt 14:47 /lib/ld-linux.so.2 ->
i386-linux-gnu/ld-2.31.so*
lrwxrwxrwx 1 root root 25 15. Jan 2021  /lib/ld-musl-x86_64.so.1 ->
x86_64-linux-musl/libc.so*

This Debian system just has both, so you cannot use this to detect musl.

(Similarily, you cannot use this to detect a pure-static musl system;
I?m told the suckless people have interest in these.)
>  |Link statically.
> 
> Nah.  For hello world you mean?
Yes, link the hello world statically so strings will show MUSL_LOCPATH
occurring. You can use -static for this, or the distro is broken.
>   #?0|kent:musl.git$ git grep -i LOCPA master
>   master:WHATSNEW:- MUSL_LOCPATH search was broken with multiple components
>   master:src/locale/locale_map.c: if (!libc.secure) path =
getenv("MUSL_LOCPATH");
Yes, this is where it comes from.
> Never heard of it.
It?s probably their equivalent of glibc LOCPATH: a path where a user
can install custom locales into.
See: https://serverfault.com/a/1093896/189656

gl hf,
//mirabilos
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