freebsd stable - Aug 2013 - Behavior of jexec

Hi,

I noticed two things when running jexec. I run FreeBSD 9.2-RC1 from
binaries and jails 9.2-RC1 too.

I log as root on the host (I havn't any other user).

# 1. $HOME

For a jail named "blog" with a "blog" user, which $HOME is
at
/home/blog, if I do:

jexec -U blog blog tcsh

My id is correct, but $HOME is still root.

# 2. Accessing a jail in ssh command line

I'm on my "client" machine and want to get on the
"server" machine,
where jails are, and I want to do a jexec from ssh command line:

ssh katana jexec -U blog blog tcsh

I get a connection (trusting /var/log/auth) but it hangs on and do
nothing. Event with a simple "ls" as jail command.

Thanks.


-- 
Florent Peterschmitt           | Please:
florent at peterschmitt.fr        |  * Avoid HTML/RTF in E-mail.
+33 (0)6 64 33 97 92           |  * Send PDF for documents.
http://florent.peterschmitt.fr | Thank you :)

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> -----Original Message-----
> From: owner-freebsd-stable at freebsd.org 
> [mailto:owner-freebsd-stable at freebsd.org] On Behalf Of 
> Florent Peterschmitt
> Sent: Friday, 16 August 2013 3:24 AM
> To: freebsd-stable at freebsd.org
> Subject: Behavior of jexec
> 
> Hi,
> 
> I noticed two things when running jexec. I run FreeBSD 
> 9.2-RC1 from binaries and jails 9.2-RC1 too.
> 
> I log as root on the host (I havn't any other user).
> 
> # 1. $HOME
> 
> For a jail named "blog" with a "blog" user, which $HOME
is at
> /home/blog, if I do:
> 
> jexec -U blog blog tcsh
> 
> My id is correct, but $HOME is still root.
> 
> # 2. Accessing a jail in ssh command line
> 
> I'm on my "client" machine and want to get on the
"server"
> machine, where jails are, and I want to do a jexec from ssh 
> command line:
> 
> ssh katana jexec -U blog blog tcsh
> 
> I get a connection (trusting /var/log/auth) but it hangs on 
> and do nothing. Event with a simple "ls" as jail command.
> 
> Thanks.
> 
> 
> -- 
> Florent Peterschmitt           | Please:
> florent at peterschmitt.fr        |  * Avoid HTML/RTF in E-mail.
> +33 (0)6 64 33 97 92           |  * Send PDF for documents.
> http://florent.peterschmitt.fr | Thank you :)
> 
> 
The behaviour is roughly what should be expected.  

It's helpful to keep in mind that the jail isn't running a getty or
login process in the context of the jail. So using
jexec -U blog blog tcsh
you'll acquire the correct ID, but be dropped into '/'.  Reading the
jail code might be the only definitive statement as to why.

When you ssh into the jail, there is no tty assigned to the session.  You can
force a tty by
ssh -t katana jexec -U blog blog tcsh
Which should give you what you require, a shell within the jail context and an
id of blog.

Regards, Dewayne.