On Sat, Aug 3, 2019 at 3:30 PM Zac Medico <zmed...@gentoo.org> wrote: > > Add _has_ipv6() function and use it in _configure_loopback_interface() > to decide whether to add an IPv6 address. > > Bug: https://bugs.gentoo.org/691290 > --- > lib/portage/process.py | 40 +++++++++++++++++++++++++++++++++++++--- > 1 file changed, 37 insertions(+), 3 deletions(-) > > diff --git a/lib/portage/process.py b/lib/portage/process.py > index 690421815..ca8b0c172 100644 > --- a/lib/portage/process.py > +++ b/lib/portage/process.py > @@ -339,6 +339,9 @@ def spawn(mycommand, env=None, opt_name=None, > fd_pipes=None, returnpid=False, > fd_pipes[1] = pw > fd_pipes[2] = pw > > + # Cache _has_ipv6() result for use in child processes. > + _has_ipv6() > + > # This caches the libc library lookup and _unshare_validator results > # in the current process, so that results are cached for use in > # child processes. > @@ -446,6 +449,38 @@ def spawn(mycommand, env=None, opt_name=None, > fd_pipes=None, returnpid=False, > # Everything succeeded > return 0 > > +__has_ipv6 = None > + > +def _has_ipv6(): > + """ > + Test that both userland and kernel support IPv6, by attempting > + to create a socket and listen on any unused port of the IPv6 > + ::1 loopback address. > + > + @rtype: bool > + @return: True if IPv6 is supported, False otherwise. > + """ > + global __has_ipv6 > + > + if __has_ipv6 is None: > + if socket.has_ipv6: > + sock = None > + try: > + # python2.7 sockets do not support context > management protocol > + sock = socket.socket(socket.AF_INET6, > socket.SOCK_DGRAM) > + sock.bind(('::1', 0)) > + except EnvironmentError: > + __has_ipv6 = False > + else: > + __has_ipv6 = True > + finally: > + if sock is not None: > + sock.close() > + else: > + __has_ipv6 = False > + > + return __has_ipv6 > + > def _configure_loopback_interface(): > """ > Configure the loopback interface. > @@ -478,9 +513,8 @@ def _configure_loopback_interface(): > > try: > subprocess.call(['ip', 'address', 'add', '10.0.0.1/8', 'dev', > 'lo']) > - with open(os.devnull, 'wb', 0) as devnull: > - subprocess.call(['ip', 'address', 'add', 'fd00::1/8', > 'dev', 'lo'], > - stdout=devnull, stderr=devnull) > + if _has_ipv6(): > + subprocess.call(['ip', 'address', 'add', 'fd00::1/8', > 'dev', 'lo']) > except EnvironmentError as e: > writemsg("Error calling 'ip': %s\n" % e.strerror, > noiselevel=-1) > > -- > 2.21.0 >
This seems reasonable, though I don't have an IPv6-less system to test it on.
