can't boot singleuser or multiuser

can't boot singleuser or multiuser

Post by Dan Strombe » Fri, 21 Mar 2003 01:45:56



I have a netra T1 at another physical location.

It was installed some time ago, and left down afterward.  I need to
somehow get into it, and patch it up before it can go into production.

When I try to boot it into single user remotely, using a console
server, I always have to hit enter twice at the password prompt, and
none of the old passwords in my password list are working.  I tried
enter, ^j and ^m, but nothing worked - I always had to hit some form
of eol twice.

So my question is twofold:

1) Does this "hit enter twice" thing*up entering an otherwise
   good password?  How can it be fixed?

2) Is there any way I can get in without the root password, short of
   schlepping a cdrom drive over there?  I'm thinking along the lines
   of "linux init=/bin/sh" or perhaps net booting an off-subnet
   install server into single user.  I tried "boot -a", but that
   didn't ask any useful questions for this purpose and got me stuck
   coming up into multiuser when it tried to start NIS, because the
   poor thing was configured without an explicit NIS binding list
   (ypinit -c).

(I have an regular account that has a passworded back door on the
system I could use to get root, if I could just get it to come up
multiuser... but it gets stuck on NIS and won't come up the rest of
the way.  I even left it booting overnight, but it was still down the
next morning)

TIA.

--
Dan Stromberg                                               UCI/NACS/DCS

 
 
 

can't boot singleuser or multiuser

Post by Ken Gonsalve » Sat, 22 Mar 2003 02:45:39


Maybe these links can help you disable the break signal requirement...

http://www.veryComputer.com/
http://www.veryComputer.com/

-
Ken Gonsalves


Quote:> I have a netra T1 at another physical location.

> It was installed some time ago, and left down afterward.  I need to
> somehow get into it, and patch it up before it can go into production.

> When I try to boot it into single user remotely, using a console
> server, I always have to hit enter twice at the password prompt, and
> none of the old passwords in my password list are working.  I tried
> enter, ^j and ^m, but nothing worked - I always had to hit some form
> of eol twice.

> So my question is twofold:

> 1) Does this "hit enter twice" thing*up entering an otherwise
>    good password?  How can it be fixed?

> 2) Is there any way I can get in without the root password, short of
>    schlepping a cdrom drive over there?  I'm thinking along the lines
>    of "linux init=/bin/sh" or perhaps net booting an off-subnet
>    install server into single user.  I tried "boot -a", but that
>    didn't ask any useful questions for this purpose and got me stuck
>    coming up into multiuser when it tried to start NIS, because the
>    poor thing was configured without an explicit NIS binding list
>    (ypinit -c).

> (I have an regular account that has a passworded back door on the
> system I could use to get root, if I could just get it to come up
> multiuser... but it gets stuck on NIS and won't come up the rest of
> the way.  I even left it booting overnight, but it was still down the
> next morning)

> TIA.

> --
> Dan Stromberg                                               UCI/NACS/DCS


 
 
 

1. Multiuser/singleuser => Multuser/unusable

Here's my understanding of how traditional unices work:

a) system boots
b) enters multiuser mode
c) login, work, do whatever
d) root does "shutdown now"
e) system goes down to singleuser
f) at the console, do whatever work is desired on root filesystem
   (e.g., vi /etc/inittab, vi /etc/passwd)
g) type control-d
e) system returns to multiuser mode, which is the EXACT SAME state as in
   step b, above (minus any changes made in step f)

My understanding is that I should be able to loop between steps b and f
as often as I like. I can't. What's the deal?

Here's how it goes for me:
(I'm running Linux 1.0.9 from the Slackware 2.0 distribution on the
InfoMagic June 1994 CDs.)

a) system boots
b) enters multiuser mode
c) login, work, do whatever
d) root does "shutdown now"
e) system goes down to singleuser
f) at the console, do no work whatsoever, because the root filesystem is
   most unhelpfully mounted read-only
g) type control-d, and answer the runlevel prompt with "5"
h) system goes to multiuser mode, but with the root filesystem still mounted
   read-only and none of the other filesystems in /etc/fstab mounted at all
i) root does "shutdown now"
j) shutdown fails because telinit can't write to the root filesystem

"mount -n -o remount /" doesn't seem to be the answer either, whether used at
step f or step h. (The problems get even more complex.)

I'm not new to unix, but I am new to unix-type system administration (only
similar experience: Coherent). Is this really how it's supposed to work. If
not, what am I missing? In fact, if this is how it's supposed to work, then
what am I missing?

Or is my installation/subsequent configuration botched?

Linux is excellent, but I just don't get this.
--
Stephen P. Kendall
Student
Indiana University-Purdue University at Indianapolis

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