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03-basic-system

README.md

Chapter 3: Basic System Build

Building the core components of the Linux system, including essential utilities and libraries.

Components to Build

  • Gettext (internationalization)
  • Bison (parser generator)
  • Perl (scripting language)
  • Python (programming language)
  • Texinfo (documentation)
  • Util-linux (system utilities)

Importance

These tools are needed to build more complex packages later in the process. This creates a self-hosting system capable of building itself.

Chapter plan (learning-first)

Learning objectives

  • Build the core userland components needed for a minimal system
  • Understand package build patterns and FHS layout used by LFS
  • Run simple integration tests to validate installations

Quick start (example)

# ensure LFS variables are setexport LFS=/mnt/lfs
export PATH=$LFS/tools/bin:$PATH# example: extract and configure gettextcd$LFS/sources
tar xf gettext-0.22.tar.xz
cd gettext-0.22
./configure --disable-shared
make && sudo make install

Exercises

  • Exercise A: Build and install gettext and run msgfmt --version to confirm.
  • Exercise B: Create a small script that checks presence and versions of Perl and Python on your build host.

Next steps

  • After the basic toolchain and core utilities are installed, proceed to Chapter 4 to configure and build the kernel with features required for containers and hardening.

Component Dependencies

graph TD
A[Toolchain] --> B[Gettext]
A --> C[Bison]
A --> D[Perl]
A --> E[Python]
A --> F[Texinfo]
A --> G[Util-linux]
B --> H[Later Packages]
C --> H
D --> I[Build Scripts]
E --> I
F --> J[Documentation]
G --> K[System Utils]
style A fill:#e8f5e8
style H fill:#c8e6c9
style I fill:#fff3e0
style J fill:#f3e5f5
style K fill:#e8f5e8
Loading

Build Process Pattern

flowchart TD
A[Download Source] --> B[Extract]
B --> C[Create Build Dir]
C --> D[Configure]
D --> E{Config OK?}
E -->|No| F[Fix Config]
E -->|Yes| G[Make]
G --> H{Build OK?}
H -->|No| I[Fix Build]
H -->|Yes| J[Make Install]
J --> K{Install OK?}
K -->|No| L[Fix Install]
K -->|Yes| M[Test]
M --> N{Test OK?}
N -->|No| O[Debug Test]
N -->|Yes| P[Clean Up]
P --> Q[Next Package]
F --> D
I --> G
L --> J
O --> M
Loading

Build Environment

Enter Chroot Environment

# Mount virtual filesystems
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 $LFS/run
# Enter chroot
chroot "$LFS" /tools/bin/env -i \
HOME=/root \
TERM="$TERM" \
PS1='\u:\w\$ ' \
PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \
/tools/bin/bash --login

Create Essential Directories

# Create FHS directories
mkdir -pv /{boot,home,mnt,opt,srv}
# Create user directories
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}
# Set permissions
ln -sfv /run /var/run
ln -sfv /run/lock /var/lock

Package Build Commands

Gettext Build

cd$LFS/sources
tar xf gettext-0.22.tar.xz
cd gettext-0.22
./configure --disable-shared
make
cp -v gettext-tools/src/{msgfmt,msgmerge,xgettext} /usr/bin

Bison Build

cd$LFS/sources
tar xf bison-3.8.2.tar.xz
cd bison-3.8.2
./configure --prefix=/usr \
--docdir=/usr/share/doc/bison-3.8.2
make
make install

Perl Build

cd$LFS/sources
tar xf perl-5.38.0.tar.xz
cd perl-5.38.0
# Configure for LFS
sh Configure -des \
-Dprefix=/usr \
-Dvendorprefix=/usr \
-Dprivlib=/usr/lib/perl5/5.38/core_perl \
-Darchlib=/usr/lib/perl5/5.38/core_perl \
-Dsitelib=/usr/lib/perl5/5.38/site_perl \
-Dvendorlib=/usr/lib/perl5/5.38/vendor_perl \
-Dvendorarch=/usr/lib/perl5/5.38/vendor_perl \
-Dman1dir=/usr/share/man/man1 \
-Dman3dir=/usr/share/man/man3 \
-Dpager="/usr/bin/less -isR" \
-Duseshrplib \
-Dusethreads
make
make install

Python Build

cd$LFS/sources
tar xf Python-3.12.0.tar.xz
cd Python-3.12.0
./configure --prefix=/usr \
--enable-shared \
--without-ensurepip
make
make install

Texinfo Build

cd$LFS/sources
tar xf texinfo-7.1.tar.xz
cd texinfo-7.1
./configure --prefix=/usr
make
make install

Util-linux Build

cd$LFS/sources
tar xf util-linux-2.39.1.tar.xz
cd util-linux-2.39.1
./configure --prefix=/usr \
--bindir=/usr/bin \
--sbindir=/usr/sbin \
--sysconfdir=/etc \
--disable-chfn-chsh \
--disable-login \
--disable-nologin \
--disable-su \
--disable-setpriv \
--disable-runuser \
--disable-pylibmount \
--disable-static \
--without-python \
--without-systemd \
--without-systemdsystemunitdir
make
make install

Testing

Verify Installations

# Test gettext
msgfmt --version
# Test bison
bison --version
# Test perl
perl -v
# Test python
python3 --version
# Test texinfo
makeinfo --version
# Test util-linux
blkid --version

Run Basic Tests

# Create test script
cat > test_system.sh << "EOF"#!/bin/bashecho "Testing basic system components..."# Test Perlperl -e 'print "Perl OK\n"'# Test Pythonpython3 -c 'print("Python OK")'# Test bisonecho "int main() { return 0; }" | bison -o /dev/null -echo "All tests passed!"EOF
chmod +x test_system.sh
./test_system.sh

Build Status Table

ComponentStatusDurationPurpose
Gettext⏳ Pending20-30 minInternationalization
Bison⏳ Pending15-25 minParser generator
Perl⏳ Pending45-60 minScripting language
Python⏳ Pending60-90 minProgramming language
Texinfo⏳ Pending15-25 minDocumentation
Util-linux⏳ Pending20-30 minSystem utilities

References

Build Environment

Enter Chroot Environment

# Mount virtual filesystems
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 $LFS/run
# Enter chroot
chroot "$LFS" /tools/bin/env -i \
HOME=/root \
TERM="$TERM" \
PS1='\u:\w\$ ' \
PATH=/bin:/usr/bin:/sbin:/usr/sbin:/tools/bin \
/tools/bin/bash --login

Create Essential Directories

# Create FHS directories
mkdir -pv /{boot,home,mnt,opt,srv}
# Create user directories
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}
# Set permissions
ln -sfv /run /var/run
ln -sfv /run/lock /var/lock

Package Build Pattern

General Build Steps

# Example for a typical packagecd$LFS/sources
# Extract
tar xf package-1.0.tar.xz
cd package-1.0
# Configure
./configure --prefix=/usr \
--sysconfdir=/etc \
--localstatedir=/var \
--disable-static \
--docdir=/usr/share/doc/package-1.0
# Build
make
# Install
make install

Gettext Build

cd$LFS/sources
tar xf gettext-0.22.tar.xz
cd gettext-0.22
./configure --disable-shared
make
cp -v gettext-tools/src/{msgfmt,msgmerge,xgettext} /usr/bin

Bison Build

cd$LFS/sources
tar xf bison-3.8.2.tar.xz
cd bison-3.8.2
./configure --prefix=/usr \
--docdir=/usr/share/doc/bison-3.8.2
make
make install

Perl Build

cd$LFS/sources
tar xf perl-5.38.0.tar.xz
cd perl-5.38.0
# Configure for LFS
sh Configure -des \
-Dprefix=/usr \
-Dvendorprefix=/usr \
-Dprivlib=/usr/lib/perl5/5.38/core_perl \
-Darchlib=/usr/lib/perl5/5.38/core_perl \
-Dsitelib=/usr/lib/perl5/5.38/site_perl \
-Dvendorlib=/usr/lib/perl5/5.38/vendor_perl \
-Dvendorarch=/usr/lib/perl5/5.38/vendor_perl \
-Dman1dir=/usr/share/man/man1 \
-Dman3dir=/usr/share/man/man3 \
-Dpager="/usr/bin/less -isR" \
-Duseshrplib \
-Dusethreads
make
make install

Python Build

cd$LFS/sources
tar xf Python-3.12.0.tar.xz
cd Python-3.12.0
./configure --prefix=/usr \
--enable-shared \
--without-ensurepip
make
make install

Texinfo Build

cd$LFS/sources
tar xf texinfo-7.1.tar.xz
cd texinfo-7.1
./configure --prefix=/usr
make
make install

Util-linux Build

cd$LFS/sources
tar xf util-linux-2.39.1.tar.xz
cd util-linux-2.39.1
./configure --prefix=/usr \
--bindir=/usr/bin \
--sbindir=/usr/sbin \
--sysconfdir=/etc \
--disable-chfn-chsh \
--disable-login \
--disable-nologin \
--disable-su \
--disable-setpriv \
--disable-runuser \
--disable-pylibmount \
--disable-static \
--without-python \
--without-systemd \
--without-systemdsystemunitdir
make
make install

Testing

Verify Installations

# Test gettext
msgfmt --version
# Test bison
bison --version
# Test perl
perl -v
# Test python
python3 --version
# Test texinfo
makeinfo --version
# Test util-linux
blkid --version

Run Basic Tests

# Create test script
cat > test_system.sh << "EOF"#!/bin/bashecho "Testing basic system components..."# Test Perlperl -e 'print "Perl OK\n"'# Test Pythonpython3 -c 'print("Python OK")'# Test bisonecho "int main() { return 0; }" | bison -o /dev/null -echo "All tests passed!"EOF
chmod +x test_system.sh
./test_system.sh

References