libcidn

[Florian Weimer]

On 10/05/2017 03:16 PM, Andreas K. Huettel wrote:

> Mostly out of curiosity, what is the usecase for the glibc-internal libidn?

It's used by getaddrinfo if the AI_IDN flag is passed.

> A quick scan on my laptop (Gentoo Linux) shows no binaries that have
> libcidn.so in NEEDED (but many with the separate libidn.so).

It's not linked directly.  getaddrinfo loads it on demand.  It's this 
way because no one has changed it yet (I tried, but got sidetracked by 
dynamic linker issues).  We should rewrite the code so that it tries 
(external) libidn2 first, then (external) libidn, and then bails out, 
and remove the actual IDN code from the library.  Some care is necessary 
because we should switch from dlsym to dlvsym for the lookup, for 
forwards compatibility.

Thanks,
Florian