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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 set
export LFS=/mnt/lfs
export PATH=$LFS/tools/bin:$PATH

# example: extract and configure gettext
cd $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/bash
echo "Testing basic system components..."

# Test Perl
perl -e 'print "Perl OK\n"'

# Test Python
python3 -c 'print("Python OK")'

# Test bison
echo "int main() { return 0; }" | bison -o /dev/null -

echo "All tests passed!"
EOF

chmod +x test_system.sh
./test_system.sh

Build Status Table

Component Status Duration Purpose
Gettext ⏳ Pending 20-30 min Internationalization
Bison ⏳ Pending 15-25 min Parser generator
Perl ⏳ Pending 45-60 min Scripting language
Python ⏳ Pending 60-90 min Programming language
Texinfo ⏳ Pending 15-25 min Documentation
Util-linux ⏳ Pending 20-30 min System 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 package
cd $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/bash
echo "Testing basic system components..."

# Test Perl
perl -e 'print "Perl OK\n"'

# Test Python
python3 -c 'print("Python OK")'

# Test bison
echo "int main() { return 0; }" | bison -o /dev/null -

echo "All tests passed!"
EOF

chmod +x test_system.sh
./test_system.sh

References