Re: can't run $chroot

[Eric Blake]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

According to SuiChangsheng on 5/21/2009 8:35 PM:
> hello, dear sir:
> Nice writing to u.
> 
> 'cos there's reason that need to 
> log in as root(e.g e:/).
> i need to use the command < chroot >
> in cygwin, however, there's problem
> please see attached file.

In the future, please copy and paste the contents of the terminal, rather
than taking a screenshot of it.  It makes it much easier to deal with in
technical lists, where HTML mail is frowned upon and plain text is the
medium of choice for bandwidth purposes.

The command chroot does nothing in cygwin.  Well, it temporarily changes
the notion of the current / directory, but it adds no security (unlike on
a real Unix system, where it makes anything outside of the new /
inaccessible to the chroot'd process hierarchy).  This is because cygwin
sits on top of the OS, and you can still bypass the cygwin layer and use
the underlying OS to access outside your new root.  Did you intend,
instead, to change the cygwin mount table of which underlying Windows
directory should be treated as the cygwin root?

> 
> Could u please help teach us why?
> Thanks so much and have a nice day!

Your screenshot showed:
$ chroot .
chroot: cannot run command `/bin/sh': No such file or directory

This would happen on any OS if you have failed to first set up the
directory to operate correctly prior to the chroot call.  In other words,
everything that your new jail environment will need (including /bin/sh)
must be replicated into the new hierarchy that you will be changing to
once you use the chroot command.

A couple of final notes - since your question is about cygwin, you may be
better off asking it on the cygwin mailing lists.  And "u" is not a word;
abbreviating "you" makes your email come across as unrefined, and you are
less likely to get favorable responses:
http://www.catb.org/~esr/faqs/smart-questions.html#writewell

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (Cygwin)
Comment: Public key at home.comcast.net/~ericblake/eblake.gpg
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iEYEARECAAYFAkoWHwsACgkQ84KuGfSFAYD5jwCgqC7RxHPQfWUg0OBUOF9MYxt8
fN8An139FNO80QfRb9bwWoMIc3fDsYy8
=WczW
-----END PGP SIGNATURE-----