LFS build helper

Provides a python3 command line tool which can generate shell scripts to build a LFS system.

The generated build scripts do not entirely automate an LFS build. E.g. most of the preparation steps and LFS configuration after the system was built are not covered by the build scripts.

The package was tested by successfully building a LFS 12.2 system. However, no thorough testing was done e.g. on different host systems and/or with different python3 versions. So, use at your own risk!

Installation

Build the lfshelper package:

cd lfshelper
python setup.py sdist

The source package to install with pip can be found in the dist directory.

Create a python virtual environment on the host system and install the lfshelper package inside it. The lxml package is a dependency and will be installed along the lfshelper package as well.

python3 -m venv lfsenv
source lfsenv/bin/activate
pip install /path/to/lfshelper/dist/lfshelper-<VERSION>.tar.gz
deactivate

Usage

Use the instructions in the LFS book to download the source packages and place them in a source directory on the host system.

Now add the html file with the "NOCHUNKS"-Version of the LFS Book and the build_db.json file corresponding to the LFS book version to this source directory.

You may have LFS configuration files available from a previous LFS install. Place these files in a separate config directory.

Activate the python environment where you installed the lfshelper package, and from within the source directory run:

lfsbuild

This creates several shell scripts in the source directory containing the commands to build the LFS system. If you created and populated the config directory, a config script with copy commands is generated as well.

After creating the scripts, deactivate the environment and continue with the preparation of the LFS build. Following the creation of the lfs user, make lfs the owner of the build scripts.

chown lfs:lfs *.sh

A list of all options of the lfsbuild script is produced with the help option:

lfsbuild --help

build_db.json

In a first pass, the lfsbuild script parses the LFS book html file and builds an internal data structure representing the sequence of chapters & sections. This includes the commands to build the LFS system given in the LFS book sections.

In a second pass, the build scripts are generated from the internal data structure. Each extracted section is identified by the id given in the LFS-BOOK-<LFS.VERSION>-NOCHUNKS.html file. Only commands from sections that are found in the build_db.json file are copied into the build scripts.

A basic entry representing a source package in the build_db.json file looks like this:

"ch-tools-m4": {
    "package_base": "m4",
    "part": ["tool1"]
}

The lookup key is the chapter/section id as used in the html "NOCHUNK" version of the LFS book.

package_base: Base name of the package without version number.

part: Part of the LFS book where this section belongs to. Recognized values are: tool1, tool2, system.

Sections in the book which contain build commands, but are not related to a source package should use "nonpackage" as value of the package_base field.

"ch-tools-kernfs": {
    "package_base": "nonpackage",
    "part": ["tool1"]
}

A newfile field with a value of true forces the lfsbuild script to close the currently generated script file and open a new one. Commands of this and the following sections are written to the new file.

Whenever the lfsbuild script encounters a call to bash or logout within the section build commands, a new file is generated automatically, i.e. the newfile field is implied in these cases.

"ch-tools-changingowner": {
    "package_base": "nonpackage",
    "part": ["tool1"],
    "newfile": true
}

The changdir field allows to adapt to sections where additional build directories are used. The value of this field is the number of directory levels that are created beneath the actual package directory level, e.g. 1 means, that the build commands in this section create one additional directory level below the package directory.

"ch-tools-binutils-pass1": {
    "package_base": "binutils",
    "changedir": 1,
    "part": ["tool1"]
}

The append field allows to append commands to a section.

"ch-tools-util-linux": {
    "package_base": "util",
    "part": ["tool2"],
    "append": [
        "rm -rf /usr/share/{info,man,doc}/*",
        "find /usr/{lib,libexec} -name \\*.la -delete"
    ]
}

With the replace field, commands can be removed or modified. The value of a replacement entry is an array where the first element is the pattern that is going to be replaced if found, and the second entry is the replacement string. If the replacement string contains %s, the value of the variable with the name given as third array element is substituted in the replacement.

 "ch-system-glibc": {
    "package_base": "glibc",
    "replace": {
        "0": ["make localedata/install-locales", ""],
        "1": ["tzselect", ""],
        "2": ["zic -d $ZONEINFO -p America/New_York", "zic -d $ZONEINFO -p %s", "timezone"],
        "3": ["ln -sfv /usr/share/zoneinfo/\n /etc/localtime", "ln -sfv /usr/share/zoneinfo/%s /etc/localtime", "timezone"]
}

The message field allows to echo messages after section commands.

"ch-system-shadow": {
        "package_base": "shadow",
        "part": ["system"],
        "replace": {
            "0": ["sed -i 's:DICTPATH.*:DICTPATH\\t/lib/cracklib/pw_dict:' etc/login.defs", ""],
            "1": ["passwd root", ""]
        },
        "message": [
            "-> Now issue: passwd root",
            "-> Then enter root password and continue with next build script"
        ]
    }

If a copy field is included inside the config key of the build db, an additional script is generated which contains commands to copy configuration files into specified folders. The generated script expects the files in a folder named config inside the directory the script is executed from.

"config": {
	"copy": [
		["ifconfig.eth0", "/etc/sysconfig"],
		["resolv.conf", "/etc"],
	]
}

Building the LFS system

To actually build the LFS system, run the generated shell scripts in the sequence given by the "_part<n>" suffix from within the source directory, e.g. like so:

time bash lfs_build_part1.sh 2>&1 | tee lfs_build_part1.log

If your build db includes the copy field and your current working directory contains a config folder with corresponding LFS config files, run the lfs_build_config.sh script to copy the config files to prespecified locations.

Depending on the included sections the build scripts need to be run as user lfs or root. Please refer to the LFS book for details.