Share emacs --daemon between 2 users of same host

Share emacs --daemon between 2 users of same host

[João Távora]

Hi,

What is the recommended way to get 2 (or more) users, say A and B, of
the same *nix host, to simulteously connect to the same emacs daemon,
each using his own emacsclient?

1. If server-use-tcp is nil, user A starts an emacs daemon which creates
a /tmp/emacs<uid>/server socket.  A connects to it fine.  But user B
can't pass that as -s to his emacsclient because of insufficient
permissions.  This is even if A chown/chmods the socket to be more
permissive.

2. If server-use-tcp is t, the same user A now creates a
~/.emacs.d/server/server file.  Again, A connects fine, but B can't pass
thjat as -f to his emacsclient because of insufficient permissions.  But
even if A chown/chmods its, there is some code that still forbits it.

Is this at all possible?  I read here[1] that is and that you even get
two simultenous cursors if two users are in the same buffer.

Thanks,
João

1: https://www.reddit.com/r/emacs/comments/7d6hv0/real_time_collaboration_in_emacs/dpvhjvu

Re: Share emacs --daemon between 2 users of same host

[Stefan Monnier]

> Is this at all possible?  I read here[1] that is and that you even get
> two simultenous cursors if two users are in the same buffer.

I'm pretty sure they're not referring to a functionality in vanilla
Emacs, unless they mean "two cursors" as in one cursor in one window and
another in another.



        Stefan

Re: Share emacs --daemon between 2 users of same host

[João Távora]

LOn Wed, Dec 5, 2018, 21:30 Stefan Monnier <monnier@iro.umontreal.ca wrote:

> > Is this at all possible?  I read here[1] that is and that you even get
> > two simultenous cursors if two users are in the same buffer.
>
> I'm pretty sure they're not referring to a functionality in vanilla
> Emacs, unless they mean "two cursors" as in one cursor in one window and
> another in another.
>

Ok, two cursors aside (definitely not a showstopper) can you tell me if
multi-user emacsclient is supported? If so, how exactly?

João

Re: Share emacs --daemon between 2 users of same host

[Stefan Monnier]

>> > Is this at all possible?  I read here[1] that is and that you even get
>> > two simultenous cursors if two users are in the same buffer.
>> I'm pretty sure they're not referring to a functionality in vanilla
>> Emacs, unless they mean "two cursors" as in one cursor in one window and
>> another in another.
> Ok, two cursors aside (definitely not a showstopper) can you tell me if
> multi-user emacsclient is supported? If so, how exactly?

You can have two emacsclients connect to a single Emacs server process.
If those two emacsclients don't belong to the same user, you'll have to
do extra work, such as copying the credentials from one user to the
other, and the result suffers from very serious trust issues (that
(temporarily) gives full access to your account to the other user).

Other approaches rely on separate sessions synchronized via
some protocol.  In that case it is often possible for the two side to
use different editors.

Check https://www.emacswiki.org/emacs/CollaborativeEditing

But AFAIK there's currently no good solution.
Of those, Rudel is in GNU ELPA and in need of a lot of love.


        Stefan