lfs-scripts 🐧

Instructions and scripts to build LFS (Linux From Scratch), version 10.1. I'm performing the build on a Fedora 34 Workstation.

Foreword

First, this guide does not replace reading the whole LFS book. I highly recommend that you read it at least once. Only then you should use the automation scripts provided here.

This build will be accomplished inside a Fedora release 34 machine.

My VM has two virtual hard disks: one for the host (Arch Linux itself) and another for building LFS. You could also use a single hard disk with two partitions, that's also up to personal taste. I've decided to use two separate hard disks so I can completely isolate LFS from the host after the build. At the end, you'll be able to create a separate VM and boot from it directly.

The packages needed to build LFS were downloaded from here (423 MB), other mirrors are available here (look for the "LFS HTTP/FTP Sites" section at the bottom, the file you need is lfs-packages-10.0.tar).

Build instructions

👉 Run commands below as root.

Create a partition and a filesystem in the virtual hard disk (/dev/sdb):

fdisk /dev/sdb

Use the following basic options: n- new partition, accept the default values, w- write changes

Create a filesystem, a mount point, and mount it:

mkfs.ext4 /dev/sdb1
mkdir /mnt/lfs
mount /dev/sdb1 /mnt/lfs

Add the following line to root's .bashrc:

export LFS=/mnt/lfs

Source the file:

source .bashrc

Download all the packages and extract them to $LFS/sources. The tcl package must be renamed in order to work with the scripts that will follow.

cd $LFS
cp /<location_of_the_package>/lfs-packages-10.0.tar .
tar xf lfs-packages-10.0.tar
mv 10.0 sources
chmod -v a+wt $LFS/sources
mv $LFS/sources/tcl8.6.10-src.tar.gz $LFS/sources/tcl8.6.10.tar.gz

Copy all the shell scripts from this repository to your $LFS directory:

cp /<location_of_the_scripts>/*.sh $LFS

Create the basic filesystem for LFS:

mkdir -pv $LFS/{bin,etc,lib,sbin,usr,var,lib64,tools}

Create the lfs user, used during the initial build process (you will have to type a password):

groupadd lfs
useradd -s /bin/bash -g lfs -m -k /dev/null lfs
passwd lfs

Make lfs own the entire filesystem:

chown -R lfs:lfs $LFS/*
chown lfs:lfs $LFS

Login as the lfs user:

su - lfs

👉 Run commands below as lfs.

Create a .bash_profile file:

cat > ~/.bash_profile << "EOF"
exec env -i HOME=$HOME TERM=$TERM PS1='\u:\w\$ ' /bin/bash
EOF

Create a .bashrc file:

cat > ~/.bashrc << "EOF"
set +h
umask 022
LFS=/mnt/lfs
LC_ALL=POSIX
LFS_TGT=$(uname -m)-lfs-linux-gnu
PATH=/usr/bin
if [ ! -L /bin ]; then PATH=/bin:$PATH; fi
PATH=$LFS/tools/bin:$PATH
export LFS LC_ALL LFS_TGT PATH
EOF

source ~/.bashrc

Run the lfs-cross.sh script, which will build the cross-toolchain and cross compiling temporary tools from chapters 5 and 6:

sh $LFS/lfs-cross.sh | tee $LFS/lfs-cross.log

Return to being root:

exit

👉 Run commands below as root.

Make root own the entire filesystem again:

chown -R root:root $LFS/*
chown root:root $LFS

Prepare virtual kernel file systems:

mkdir -pv $LFS/{dev,proc,sys,run}
mknod -m 600 $LFS/dev/console c 5 1
mknod -m 666 $LFS/dev/null c 1 3
mount -v --bind /dev $LFS/dev
mount -v --bind /dev/pts $LFS/dev/pts
mount -vt proc proc $LFS/proc
mount -vt sysfs sysfs $LFS/sys
mount -vt tmpfs tmpfs $LFS/run
if [ -h $LFS/dev/shm ]; then
  mkdir -pv $LFS/$(readlink $LFS/dev/shm)
fi

Enter the chroot environment:

chroot "$LFS" /usr/bin/env -i   \
    HOME=/root                  \
    TERM="$TERM"                \
    PS1='(lfs chroot) \u:\w\$ ' \
    PATH=/bin:/usr/bin:/sbin:/usr/sbin \
    /bin/bash --login +h

Create essential directories, files and symlinks:

mkdir -pv /{boot,home,mnt,opt,srv}
mkdir -pv /etc/{opt,sysconfig}
mkdir -pv /lib/firmware
mkdir -pv /media/{floppy,cdrom}
mkdir -pv /usr/{,local/}{bin,include,lib,sbin,src}
mkdir -pv /usr/{,local/}share/{color,dict,doc,info,locale,man}
mkdir -pv /usr/{,local/}share/{misc,terminfo,zoneinfo}
mkdir -pv /usr/{,local/}share/man/man{1..8}
mkdir -pv /var/{cache,local,log,mail,opt,spool}
mkdir -pv /var/lib/{color,misc,locate}
ln -sfv /run /var/run
ln -sfv /run/lock /var/lock
install -dv -m 0750 /root
install -dv -m 1777 /tmp /var/tmp
ln -sv /proc/self/mounts /etc/mtab
echo "127.0.0.1 localhost $(hostname)" > /etc/hosts
cat > /etc/passwd << "EOF"
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/dev/null:/bin/false
daemon:x:6:6:Daemon User:/dev/null:/bin/false
messagebus:x:18:18:D-Bus Message Daemon User:/var/run/dbus:/bin/false
nobody:x:99:99:Unprivileged User:/dev/null:/bin/false
EOF
cat > /etc/group << "EOF"
root:x:0:
bin:x:1:daemon
sys:x:2:
kmem:x:3:
tape:x:4:
tty:x:5:
daemon:x:6:
floppy:x:7:
disk:x:8:
lp:x:9:
dialout:x:10:
audio:x:11:
video:x:12:
utmp:x:13:
usb:x:14:
cdrom:x:15:
adm:x:16:
messagebus:x:18:
input:x:24:
mail:x:34:
kvm:x:61:
wheel:x:97:
nogroup:x:99:
users:x:999:
EOF
touch /var/log/{btmp,lastlog,faillog,wtmp}
chgrp -v utmp /var/log/lastlog
chmod -v 664  /var/log/lastlog
chmod -v 600  /var/log/btmp
exec /bin/bash --login +h

Run the lfs-chroot.sh script, which will build additional temporary tools:

sh /lfs-chroot.sh | tee /lfs-chroot.log

Cleanup before the final build phase:

find /usr/{lib,libexec} -name \*.la -delete
rm -rf /usr/share/{info,man,doc}/*

For the final build phase, run the lfs-system.sh script:

sh /lfs-system.sh | tee /lfs-system.log

You must now set a password for the root user (you will have to type a password):

passwd root

Logout from the chroot environment and re-enter it with updated configuration:

logout
chroot "$LFS" /usr/bin/env -i          \
    HOME=/root TERM="$TERM"            \
    PS1='(lfs chroot) \u:\w\$ '        \
    PATH=/bin:/usr/bin:/sbin:/usr/sbin \
    /bin/bash --login

Run the final script to configure the rest of the system:

sh /lfs-final.sh | tee /lfs-final.log

The end

You can now create a new VM using the virtual hard disk with the LFS build. It will be bootable and fully functional. Enjoy!