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Welcome to the Slackware Documentation Project

Setting up a Slackware chroot

There are multiple reasons why you might want to set up a Slackware chroot:

  • building 32-bit packages on a 64-bit multilib system
  • building -stable packages on a -current system
  • building (and testing) packages for SBo on a clean system

For this guide, we'll create a chroot at /chroot_folder from slackware-14.1-install-dvd.iso.

Obtaining a Slackware installation of your desired architecture

Start with a Slackware installation DVD. Download it from from http://www.slackware.com/getslack/ via torrent.

Installing the packages

Automatically

You can create your chroot and install Slackware into it using the following elegant script: http://tty1.uk/scripts/slackware/mkchroot

Manually

First, create a folder which will contain the chroot:

mkdir /chroot_folder

Mount the installation ISO:

mount -o loop slackware-14.1-install-dvd.iso /mnt/cdrom
cd /mnt/cdrom

After the ISO has been mounted, the packages (found under the slackware or slackware64 folder) can be installed to the chroot folder with:

installpkg --root /chroot-folder */*.t?z

Then unmount the ISO:

umount /mnt/cdrom

Setting up required files

fstab

The following minimal snippet can be used for /chroot_folder/etc/fstab

# <file system> <mount point>   <type>  <options>       <dump>  <pass>
tmpfs           /dev/shm        tmpfs    defaults        0      0
devpts          /dev/pts        devpts   noexec,nosuid,gid=tty,mode=0620  0      0
sysfs           /sys            sysfs    defaults        0      0
proc            /proc           proc     defaults        0      0

Entering the Chroot

Automatic mount

To have the chroot mounted permanently, add the following to your host system's /etc/fstab:

/dev             chroot_folder/dev             none bind,auto 0 0
/proc            chroot_folder/proc            none bind,auto 0 0
/sys             chroot_folder/sys             none bind,auto 0 0
/etc/resolv.conf chroot_folder/etc/resolv.conf none bind,auto 0 0

And reboot. Then run the following command to mount the chroot folder:

mount /chroot_folder

Manual mount

Refer to: (volume_mounting).

Entering the Chroot

Now that the chroot is set up, one can chroot into it:

chroot /chroot_folder /bin/bash

Note

Wrote a small script to automate the chroot steps.

https://raw.githubusercontent.com/aadityabagga/scripts/master/chroot.sh

Updating packages

After that, you can run slackpkg and update the packages: (configure_a_package_manager).

Exiting

When you're done, exited the chroot by pressing Ctrl+d.

Usecase: Building 32-bit Packages

Mounting partitions

I use a chroot to build 32-bit packages on a 64-bit system. I needed to mount the partition which contained the SlackBuilds for which I wanted to make a package, As my Slackware host mount point is (in this example) at /slackware_host_mount_point, I used the command:

mount -B /slackware_host_mount_point /chroot_folder

(http://www.thegeekstuff.com/2013/01/mount-umount-examples/)

Then I built the package by executing the Slackbuild as follows:

ARCH=i686 ./my_package.SlackBuild

An alternative way to build other ARCH packages

Instead of using `ARCH=i686' before running a slackbuild, we can use a program called `setarch', which, among other things, can set the ARCH and the kernel version in the shell. It has some handy symlinks, such as linux32 or i586, which saves some typing. The `linux32' command will set the reported kernel's ARCH as `i686'.

SYNOPSIS

  setarch arch [options] [program [argument...]]

When we run `linux32' it starts a new shell, so we can also use it to chroot:

  chroot /path/to/chroot linux32 /bin/zsh

or it could be run after chrooting into our new root. Settings will revert to normal when we exit the new shell. One useful option is to change the kernel's reported version:

  chroot /path/to/chroot linux32 --uname-2.6 /bin/zsh

That `–uname-2.6' isn't a typo, there has to be a dash between the flag and the version. The setarch(8) man page shows all the options.

– Dave

See also

Sources

* Originally written by Aaditya


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