failure on musl when idn is enabled

[prometheanfire]

Musl built with this patch, git master.

https://paste.pound-python.org/show/fL41zvIQn8jvybYXkfpm/

If built with idn (or idn2, both tested) enabled all lookups won't happen. Here's a strace.

strace -s 4096 -o /tmp/ping.strace.log /bin/ping -c 1 www.köln.de

https://paste.pound-python.org/show/qdiPCezgEoizMp1y0d3G/

even when not trying an idn I get failures

# ping google.com
ping: google.com: Invalid flags

[okias]

https://github.com/iputils/iputils/pull/111 there is already unfinished pull request for this fix.

[prometheanfire]

yep, he's updating the PR iirc, fixes the build, but not the runtime issues.

[okias]

if you can, please send pull request, it does build test etc. :)

I'll merge change as it pass build test.

[prometheanfire]

ok, now we just need runtime tests to work (ping totally fails with idn, whether or not pinging an idn address).

[kerolasa]

Mostly reproduced. idn name resolution does not work.

$ export CC=musl-clang
$ meson builddir -DBUILD_NINFOD=false -DUSE_CAP=false -DUSE_CRYPTO=none -DUSE_IDN=true
$ sudo chown root: builddir/ping
$ sudo setcap cap_net_raw+ep builddir/ping
$ ./builddir/ping éire.icom.museum
ping: éire.icom.museum: Name does not resolve

But my musl build worked fine when pinging IP or none-idn name.

[kerolasa]

musl libc site seems to be down (2018-10-20T10:01+00:00). Never mind, googling around gave me impression musl does not have support for IDN, so 'Name does not resolve' is pretty much as good as this gets right now.

[okias]

glibc supports IDN (non-ASCII name lookups via DNS) but requires the use of custom non-standard flags to getaddrinfo and getnameinfo to convert such names to/from the internal representation used in the DNS system (Punycode). musl does not yet support IDN conversions at all (but programs that know about IDN/Punycode and do the conversions themselves can of course lookup such names), but when support is added, it will always be enabled rather than requiring explicit options from the application.

[ https://wiki.musl-libc.org/functional-differences-from-glibc.html ]

[pevik]

It'd be nice to implement error message in our meson build configuration to treat this. Or at least document this problem.

[kerolasa]

It'd be nice to implement error message in our meson build configuration to treat this.

musl does not make it easy to notice it is in use[1][2]. And when looking into musl git[3] I see various IDN header requirements in place, so it is not obvious to me how to detect if IDN is or isn't implemented. Documentation snippet from @okias to gives me impression IDN support will be added later, transparently, so that downstream code does not need to do anything.

Just for record I am strictly against simple 'if musl do not allow IDN' exclusion. When musl delivers IDN that would harmful way nullify their efforts. In other words, only and only-if good IDN feature check can be found add build condition is ok.

Meanwhile I don't have anything better to offer than wait for musl folks. If someone has time and skills I'm sure musl folks do not mind getting IDN enabling contributions.

[1] https://wiki.musl-libc.org/faq.html#Q:-Why-is-there-no-%3Ccode%3E__MUSL__%3C/code%3E-macro? [2] http://git.savannah.gnu.org/cgit/automake.git/tree/lib/config.guess#n154 [3] git://git.musl-libc.org/musl see include/netdb.h file

Or at least document this problem.

I consider this issue to be documentation of the problem.