Re: Bugs in Hurd's recvmsg (msg_name AF_LOCAL, MSG_DONTWAIT)

[Christian Seiler]

On 08/01/2016 12:08 PM, Christian Seiler wrote:
> I've now isolated the problems and have a reproducer (attached)
> and it has _nothing_ to do with SCM_CREDS, but with much more
> basic functionality.
> 
> Problem 1 (causing SIGLOST):
> 
> When msg_name and msg_namelen are filled for a SOCK_STREAM AF_LOCAL
> socket (maybe also other AF_LOCAL, didn't check) upon calling
> recvmsg, SIGLOST is generated. After reading up on this a bit, it
> appears to be that Hurd doesn't have peer names for anoymous
> AF_LOCAL sockets (in contrast to Linux and kFreeBSD) - but even in
> that case, I would've expected errno = EINVAL and not SIGLOST, so
> this is definitely a bug.

Now reported as Debian Bug #833558 in pkg:libc0.3 (src:glibc).
https://bugs.debian.org/833558
Also, see previous mail, upstream bug report:
https://sourceware.org/bugzilla/show_bug.cgi?id=20444

> Problem 2:
> 
> MSG_DONTWAIT is ignored for recvmsg, it always blocks (at least
> when using AF_LOCK sockets). I've even tried to pre-fill the
> msg_flags member with it (which you shouldn't need to do
> according to POSIX, the flags argument should be enough), but
> that also doesn't help.

Now reported as Debian Bug #833557 in pkg:hurd.
https://bugs.debian.org/833557

Would be great if these fixes could be applied.

Thanks,
Christian