Re: Another system management tool to disappear.
Hi.
On Mon, 31 Aug 2015 19:40:54 +0100
Lisi Reisz <lisi.reisz@gmail.com> wrote:
> On Monday 31 August 2015 19:27:31 Reco wrote:
> > Hi.
> >
> > On Mon, 31 Aug 2015 18:25:09 +0100
> >
> > Lisi Reisz <lisi.reisz@gmail.com> wrote:
> > > On Monday 31 August 2015 16:59:48 Nicolas George wrote:
> > > > Le quartidi 14 fructidor, an CCXXIII, Lisi Reisz a écrit :
> > > > > For those who have still not discovered, you have to press ^ three
> > > > > times in succession inside a second.
> > > > >
> > > > > https://tlhp.cf/lennart-poettering-su/
> > > >
> > > > Are you referring to that snippet:
> > > >
> > > > # Connected to the local host. Press ^] three times within 1s to exit
> > > > session.
> > > >
> > > > ... or are you referring to other parts of the page that I missed or
> > > > parts in the video?
> > > >
> > > > If you are referring to that snippet, I suspect you are reading it
> > > > wrong.
> > > >
> > > > For once, it is "^]", i.e. Ctrl-], i.e. ASCII 0x1D, aka "group
> > > > separator".
> > > >
> > > > You can notice it is the same as the "escape character" present in most
> > > > telnet implementations.
> > > >
> > > > And my second point is: it is obviously meant for emergency exit, like
> > > > tilde-point in SSH. You should need it almost never in normal use,
> > > > where you exit either by typing the command "exit" or by sending the
> > > > EOF code (usually Ctrl-D), just like su.
> > > >
> > > > Actually, AFAIK neither sudo nor su support an emergency exit sequence.
> > > > If that has not bothered you until now, it should not bother you from
> > > > now on either.
> > >
> > > Then I have misunderstood, which does not surprise me.
> > >
> > > What is the alternative to su that there is so much fuss about? And I
> > > don't care about the session ending function it apparently has. <su>
> > > will change me to root and <su $USER> will change me to the user. Is
> > > that what people fear will disappear? And what do they fear will be put
> > > in its place? (Yes, I understand that so far it is in addition, not
> > > instead of, but what is the fuss about? What has Lennart proposed?)
> >
> > It's really simple.
> >
> > 1) Boot with init=/bin/sh kernel commandline.
> >
> > 2) Invoke su - <some_user>. Observe the result.
> >
> > 3) Invoke "machinectl shell". Observe the result.
> >
> > 4) Compare results from 2) and 3).
>
> Thanks for the replies. But I still don't know what is "going" and what
> is "coming".
2) should work. 3) should not.
Since booting with "init=/bin/sh" is one of the valid ways of
thoubleshooting failing OS, replacing "su" with "machinectl shell"
effectively limits usefulness of such approach.
I'm *not* saying that it will render "boot with init=/bin/sh"
completely useless, for the record. But this long road consists of
small steps, and some of them have been taken already.
> Oh well, I shall no doubt discover. At the moment on my Jessie machine I can
> open a terminal, su into root, perform whatever it is, and su out.
>
> I'll worry about it when/if I can't.
That's my approach too (but I have the contingency plan already :).
> Is the proposed change only going to have an effect so early in the process?
Of course, not. "machinectl login" should provide the user with a new
"session" (whatever that term means in newspeak). The whole idea of [1]
is that "su" does not do so (whenever it should is another topic),
therefore "su" should be replaced.
[1] https://github.com/systemd/systemd/issues/825
Reco
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