On Wed, Jul 31, 2019 at 2:00 PM Zac Medico <zmed...@gentoo.org> wrote:
>
> On 7/31/19 9:06 AM, Mike Gilbert wrote:
> > This works around some strange behavior in glibc's getaddrinfo()
> > implementation when the AI_ADDRCONFIG flag is set.
> >
> > For example:
> >
> > struct addrinfo *res, hints = { .ai_family = AF_INET, .ai_flags =
> > AI_ADDRCONFIG };
> > getaddrinfo("localhost", NULL, &hints, &res);
> >
> > This returns no results if there is no non-loopback interface configured
> > with an
> > IPv4 address.
> >
> > Bug: https://bugs.gentoo.org/690758
> > Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=12377#c13
> > Signed-off-by: Mike Gilbert <flop...@gentoo.org>
> > ---
> > lib/portage/process.py | 24 ++++++++++++++++++++++++
> > 1 file changed, 24 insertions(+)
> >
> > diff --git a/lib/portage/process.py b/lib/portage/process.py
> > index dfbda75de..c284c04f3 100644
> > --- a/lib/portage/process.py
> > +++ b/lib/portage/process.py
> > @@ -446,6 +446,29 @@ def spawn(mycommand, env=None, opt_name=None,
> > fd_pipes=None, returnpid=False,
> > # Everything succeeded
> > return 0
> >
> > +def _configure_dummy_interface():
> > + """
> > + Configure a dummy interface to work around odd behavior in glibc's
> > + getaddrinfo() implementation when the AI_ADDRCONFIG flag is set.
> > +
> > + For example:
> > +
> > + struct addrinfo *res, hints = { .ai_family = AF_INET, .ai_flags =
> > AI_ADDRCONFIG };
> > + getaddrinfo("localhost", NULL, &hints, &res);
> > +
> > + This returns no results if there is no non-loopback interface
> > configured with an
> > + IPv4 address.
> > +
> > + Bug: https://bugs.gentoo.org/690758
> > + Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=12377#c13
> > + """
> > + try:
> > +
> > subprocess.check_call(['ip','link','add','dummy','type','dummy'])
> > + subprocess.check_call(['ip','link','set','dummy','up'])
> > +
> > subprocess.check_call(['ip','address','add','10.0.0.1/8','dev','dummy'])
> > + except subprocess.CalledProcessError:
> > + writemsg("Unable to configure dummy network interface\n")
> > +
> > def _exec(binary, mycommand, opt_name, fd_pipes,
> > env, gid, groups, uid, umask, cwd,
> > pre_exec, close_fds, unshare_net, unshare_ipc, unshare_mount,
> > unshare_pid,
> > @@ -637,6 +660,7 @@ def _exec(binary, mycommand, opt_name, fd_pipes,
> >
> > errno.errorcode.get(e.errno, '?')),
> >
> > noiselevel=-1)
> > sock.close()
> > +
> > _configure_dummy_interface()
> > except AttributeError:
> > # unshare() not supported by libc
> > pass
> >
>
> Maybe it will suffice to add the address to the loopback interface?
I wasn't expecting that to work, but it actually does! That makes this
a bit simpler indeed. I'll send a new patch in a bit.
