commit: 7d05c3e88dd313e3298d74ce7241cbc5b85df54a Author: Zac Medico <zmedico <AT> gentoo <DOT> org> AuthorDate: Sat Aug 3 18:40:31 2019 +0000 Commit: Zac Medico <zmedico <AT> gentoo <DOT> org> CommitDate: Sun Aug 4 17:41:25 2019 +0000 URL: https://gitweb.gentoo.org/proj/portage.git/commit/?id=7d05c3e8
process: add _has_ipv6() function 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 Reviewed-by: Mike Gilbert <floppym <AT> gentoo.org> Signed-off-by: Zac Medico <zmedico <AT> gentoo.org> lib/portage/process.py | 43 ++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 40 insertions(+), 3 deletions(-) diff --git a/lib/portage/process.py b/lib/portage/process.py index 690421815..2a2cbd972 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 +449,41 @@ 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: + # With ipv6.disable=0 and ipv6.disable_ipv6=1, socket creation + # succeeds, but then the bind call fails with this error: + # [Errno 99] Cannot assign requested address. + sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM) + sock.bind(('::1', 0)) + except EnvironmentError: + __has_ipv6 = False + else: + __has_ipv6 = True + finally: + # python2.7 sockets do not support context management protocol + if sock is not None: + sock.close() + else: + __has_ipv6 = False + + return __has_ipv6 + def _configure_loopback_interface(): """ Configure the loopback interface. @@ -478,9 +516,8 @@ 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)
