Re: [PATCH 4/8] man/man7/unix.7: Explain Abstract UDS scoping to the network namespace

[Kuniyuki Iwashima <kuniyu@google.com>]

On Mon, 26 Oct 2026 22:11:56 +0100, Günther Noack wrote:
> Hello! Thanks for the review!
> 
> On Sat, Oct 24, 2026 at 05:39:52AM +0000, Kuniyuki Iwashima wrote:
> > On Wed, 21 Oct 2026 23:07:56 +0200, Günther Noack wrote:
> > > Point out that Abstract Unix Domain Sockets are visible within the
> > > current network namespace, unlike Named Unix Domain Sockets, where the
> > 
> > s/Named/pathname/.
> > 
> > pathname, unnamed, abstract are used in Address format section.
> 
> Thanks, fixed.
> 
> 
> > > remote socket is looked up through the mount namespace.
> > > 
> > > To avoid confusion, remove the word "namespace" from the subsequent
> > > paragraph, where it is used in a more colloquial form (there is no
> > > abstract socket namespace in the sense of namespaces(7)).
> > 
> > The change still uses "abstract socket namespace".
> 
> In the "Abstract Sockets" section, the word "namespace" is not used
> any more in the general sense, but only in the sense of a
> setns(2)/namespaces(7) namespace.
> 
> There are some places in the man page where the word "namespace" is
> still used colloquially, but these are not in the vicinity of this
> change and feel less prone to confusion.  Do you think I should update
> these all in the same commit?

I understand the "namespace" itself is a generic word but it
feels a bit odd as it most likely means CLONE_NEWXXX in Linux.

But fixing up all would be apparently boring, so I'll let you
decide, and leaving them as is is 100% fine ;)


> 
> 
> > > This is already described in network_namespaces(7) as well, but might
> > > be mentionworthy here too.
> > > 
> > > The lookup of Abtract addresses happens in __unix_find_socket_byname()
> > > in linux.git net/unix/af_unix.c, where it is looked up in the network
> > > namespace (struct net *net) in a hash table in that namespace:
> > > 
> > > 	sk_for_each(s, &net->unx.table.buckets[hash]) {
> > > 		// ...
> > > 	}
> > > 
> > > Cc: Kuniyuki Iwashima <kuniyu@google.com>
> > > Assisted-by: LLM
> > > Signed-off-by: Günther Noack <gnoack3000@gmail.com>
> > > ---
> > > 
> > > Notes:
> > >     Verified in code
> > > 
> > >  man/man7/unix.7 | 12 +++++++++++-
> > >  1 file changed, 11 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/man/man7/unix.7 b/man/man7/unix.7
> > > index 4c46b54206a5..232fdbf4c3cd 100644
> > > --- a/man/man7/unix.7
> > > +++ b/man/man7/unix.7
> > > @@ -257,7 +257,17 @@ has no effect on the accessibility of the socket.
> > >  Abstract sockets automatically disappear when all open references
> > >  to the socket are closed.
> > >  .P
> > > -The abstract socket namespace is a nonportable Linux extension.
> > > +Each network namespace has its own abstract socket namespace (see
> > > +.BR network_namespaces (7)):
> > 
> > Remove this sentence and...
> > 
> > 
> > > +a socket can connect or send to an abstract address
> > > +only if the socket bound to that address
> > > +is in the same network namespace.
> > 
> > add "(see network_namespaces (7))" here.
> 
> Good idea, that's shorter.
> 
> 
> > > +In contrast,
> > > +pathname sockets are not confined to a network namespace;
> > > +they can be reached from any network namespace
> > > +in which the socket file is accessible.
> > > +.P
> > > +Abstract sockets are a nonportable Linux extension.
> > >  .\"
> > >  .SS Socket options
> > >  For historical reasons, these socket options are specified with a
> > > -- 
> > > 2.56.0
> > > 
> 
> Thanks,
> –Günther