32-Bit Chroot How-To

[cesera]

Thank you for this howto. It works well for me (on dapper). I have however one little problem. I have some of my home directories on seperate partitions, and even though I have added:

/home /chroot/home none bind 0 0

to my /etc/fstab file I cannot enter the home directories that are on seperate partitions (mounted on /home/<user>), but the home directories that are just normal directories on /home work fine, any idea what causes this?

PS. just tested some other partitions mounted within the directory structure, and I don't seem to be able to cross the mount-point boundary from within the chroot environment.

[chrestomanci]

Thank you for this howto. It works well for me (on dapper). I have however one little problem. I have some of my home directories on separate partitions, and even though I have added:

/home /chroot/home none bind 0 0

to my /etc/fstab file I cannot enter the home directories that are on separate partitions (mounted on /home/<user>), but the home directories that are just normal directories on /home work fine, any idea what causes this?

The solution is to create similar chroot mounts for each mounted partition on your system, so in your case a section of your /etc/fstab might look like this:

# Separate mounts for each user's home dir
/dev/sdb1   /home/alice     ext3    none    0   2
/dev/sdb2   /home/bob       ext3    none    0   2
/dev/sdb3   /home/charles   ext3    none    0   2
/dev/sdb4   /home/david     ext3    none    0   2

# Chroot mount points so that users can access their files using 32bit chroot programs
/home/alice     /chroot/home/alice     none bind    0   0
/home/bob       /chroot/home/bob       none bind    0   0
/home/charles   /chroot/home/charles   none bind    0   0
/home/david     /chroot/home/david     none bind    0   0

You will also need to create a chroot mount point for each removable device that you want to use. Also if you have more than one chroot environment setup you will need to create a set of these mount points for each environment.

Needless to say this is all a bit of a pain if you have loads of partitions and several chroot environments. I am working on a script to automate the process.

[cesera]

I used the 32-bit chroot successfully for a while and then came to a point where I didn't need it anymore. So I removed the /chroot from my system, this took a lot longer than I expected so I cancelled it and looked what was happening. To my horror I realised that my home directory was mounted within /chroot (I had forgotten about this) and was now mostly empty. (Thankfully I had a backup.)

Moral of the story: umount everything mounted within /chroot before removing it. (Maybe it is wise to add a warning to the howto, in case there are other idiots like me out there.)

[flygin]

symlink an application to chroot including man pages, doc folders, menu (!), icons and .desktop file

check it out here:

http://www.geocities.com/thierryguy/

[fireandlight27]

Works great for me under Dapper. Thanks for the great how-to. The one thing I've noticed that doesn't work is mail-to links. Clicking on a mail-to link has no effect. Is there a way to fix this without installing a mail client in the chroot?

[chrestomanci]

Works great for me under Dapper. Thanks for the great how-to. The one thing I've noticed that doesn't work is mail-to links. Clicking on a mail-to link has no effect. Is there a way to fix this without installing a mail client in the chroot?

Not easily. Unfortunately this is a bit of a thorny problem.

When you click on a mailto: link, your web browser attempts to start an email program so that you can compose and send your mail message. The problem is that programs running inside the chroot cannot see outside it, so they cannot access your mail program.

As you suggest, one solution would be to install a mail client inside the chroot, and to configure your browser inside the chroot to use it. There would be some problems with this, one is that the mail client inside the chroot might confuse your normal one if they are both running at the same time and try to access the same locally stored folders. If the mail client has its own separate set of folders, then your mail messages would not all be together, and if you where looking for a message you sent some time ago, you would have to look in both mail clients. Both these problems can be solved by keeping your mail folders on an IMAP server, and having both clients talk to that server.

Also, the mail client would not be able to see your copy of sendmail, though this is unlikely to be a problem as most clients default to sending mail using TCP/IP sockets rather than calling sendmail directly.

An alternative solution would be to find a way to invoke programs in the parent system from within the chroot. It should be fairly easy to write a script that uses remote procedure calls to achieve this by calling out of the chroot to a listener running in the host OS. I don’t know if such a script or program is available. If you can’t find one, and you are competent at programming you might consider writing one yourself and posting it here.

There is also a third issue if you are sending mailto links the other way, (from a browser in the host OS, to a mail client in the chroot). Currently when the do_chroot script passes program arguments to the chroot, it does not protect special characters from being interpreted by the shell, so a command line such as:

thunderbird ‘john.doe@example.com’

Will get messed up because the quote and @ symbols are special and will be cause errors. Puiphooey has posted an alternative version that protects spaces but not any other special character. I am currently working on a do_chroot replacement to fix this and other issues.

[feldegast]

i found that you need to do the following before synaptic will install within the chroot.

apt-get install locales

[Iesos]

Hi.
Made the update to edgy a few days ago. And my chroot broke down. Now I'm trying to get it back up, by doing this guide again. But I get this error trying to enter chroot:

$ sudo chroot /chroot/
Password:
/bin/bash: /lib/tls/i686/cmov/libc.so.6: version `GLIBC_2.4' not found (required by /bin/bash)
/bin/bash: /lib/tls/i686/cmov/libc.so.6: version `GLIBC_2.3.4' not found (required by /bin/bash)

Anyone know anything about it?

[ronelly]

well as you can see this is my first post here. i'm loving this distro / community because through you guys i actually have my ati card working lol. i'm trying to set up the 32 bit environment as per this guide.. but i'm getting these errors.




Errors were encountered while processing:
postfix
at
mailx
mutt
postfix-tls
ubuntu-base
E: Sub-process /usr/bin/dpkg returned an error code (1)
jimbo@ubuntu:~$ sudo ln -s /usr/sbin/synaptic /usr/sbin/synaptic32
jimbo@ubuntu:~$ exit
exit
jimbo@ubuntu:~$ sudo ln -s /usr/local/bin/do_dchroot /usr/local/bin/synaptic32
jimbo@ubuntu:~$ sudo synaptic32
(hoary) synaptic32

(synaptic32:28009): Gtk-CRITICAL **: gtk_tree_view_unref_tree_helper: assertion `node != NULL' failed

any help would be appreciated, i'm all aquiver at the idea of finally being able to leave behind windows. if i can get this 32 bit setup.. set up, then wow working.. i wouldn't need windows for anything anymore

hi,
I am having the same problem. did you manage to solve it? I appreciate any help!
thanx,
ronny

[Funzo22]

Hi.
Made the update to edgy a few days ago. And my chroot broke down. Now I'm trying to get it back up, by doing this guide again. But I get this error trying to enter chroot:

$ sudo chroot /chroot/
Password:
/bin/bash: /lib/tls/i686/cmov/libc.so.6: version `GLIBC_2.4' not found (required by /bin/bash)
/bin/bash: /lib/tls/i686/cmov/libc.so.6: version `GLIBC_2.3.4' not found (required by /bin/bash)

Anyone know anything about it?

I solved this problem quite simply by reinstalling my whole chroot system, I guess this solution wont work for you if you have spent time configuring it or whatever, but if your chroot'd environment is relatively empty just do this:

sudo rm -r /chroot

and follow the guide again but replace all instances of breezy with edgy and voila a working chroot environment with edgy