Pierre Labastie 35094eda67 Major refactoring of README
Describe each item in the menu, fix layout, and try to follow
the order of tasks to do to run jhalfs.
2023-11-23 10:07:45 +01:00

413 lines
18 KiB

The scripts in this directory implement an automation of the building
of a GNU/LInux system, as described in the Linux From Scratch book series.
The name of the project is jhalfs: in that name, "alfs" stands for
"automated linux from scratch", and the initials "jh" have been kept since
the original "jhalfs-0.2" code developed by Jeremy Huntwork.
The list of supported books can be found at (maybe outdated,
current develoment books and latest version are always supported).
The documentation is split among various README.* files. Here is a list
of what is in which:
- README (this file): instructions to use the LFS book. This should be
enough if you just want to build a base system as per the LFS book. It
is also a required reading for all the other projects.
- README.BLFS: instructions to install an automated build infrastructure
for the BLFS book. There are two ways to do so: (i) install the
tools at the end of an LFS build, or
(ii) install the tools on an already running system. Both methods are
described in that file.
- README.CUSTOM: instructions to run custom commands either during the LFS
build, or at the end of a LFS build. Note that you will not find
instructions on how to write those commands, but some examples are
- README.PACKAGE_MANAGEMENT: instructions to use package management during
the build (Note: the only package manager that is regularly tested is
Other sources of information are the context help in the menu interface,
and the LFS books themselves (both required readings of course!).
It is strongly advised that you first build manually a complete system
before attempting to automate the build.
Of course the "Host System Requirements" should be fulfilled. Some
supplementary packages are needed for using jhalfs. They are detailed
at the bottom of the page: In short, you need
wget, sudo, libxml2, libxslt, docbook-4.5-xml, and docbook-xsl-nons.
No installation is required. You may want to move the files in this
directory to a convenient location, and then follow the instructions below.
There is no configuration of the tools themselves. The various
parameters for the build are set through a menu driven interface. See
the section RUNNING below for details.
This tool has no support at all for creating a partition and a mount
point for the built system. You should follow the book up to the section
"Mounting the new partition". Note that the default name for the
partition mount point is "/mnt/build_dir", instead of /mnt/lfs.
You can change that default to anything you'd like in the menu, so you
may name it /mnt/lfs if you prefer . We'll use the name /mnt/build_dir
in the sequel.
For downloading packages, you can use the tool or download them
yourself. Even if using the tool, it is recommended to set up a source
repository where you store already downloaded packages. The tool will
automatically search a package in this repository before downloading it
if it is not found there. This repository cannot be the same as
/mnt/build_dir/sources. As an example, we'll use /usr/src. You should
arrange for the user running the tool to have write access to this
If you want to build the kernel as part of the automated build,
a configuration file must be provided. In order to do so, it is
recommended to download the kernel tarball, unpack it, run
<make menuconfig> (or any other *config), configure the kernel as per
the book, and save the resulting .config file to a location where it can
be retrieved later on. It is suggested to put it into the source
repository, with a versioned name, e.g.
/usr/src/config-<arch>-<kernel version>-<config details>.
Another file you may provide is the fstab file. As for the kernel
configuration, this file has to be prepared before running the menu.
You can copy-paste the file from the "Creating the /etc/fstab File"
page, then edit to suit the future lfs system layout, then save the
file. A convenient location and name is /usr/src/fstablfs.
At a more advanced level, you may want to supply custom commands
to be run at the end of LFS build. Scripts containing those commands
are located in the ./custom/config directory. Examples are given in
./custom/examples. A template is provided as ./custom/template. See
README.CUSTOM for more details.
You must be logged as a normal user with sudo privileges to run
the Makefile. Furthermore, you are supposed to have enough privilege
to become any user. If you are not bothered about security issues,
the entry for the user running the tool in /etc/sudoers could be
The command <make> will launch a menu based configuration program,
similar to the kernel "menuconfig" configuration tool.
Help on parameter function is available from the on-line help (type the
character `?' after highlighting the parameter). Please do use the help:
it may contain additional information not duplicated in this file.
MENU "BOOK Settings"
Use BOOK: You have three choices: LFS System V, LFS systemd, BLFS.
The BLFS part is described in README.BLFS
Book version: You have two choices: "Branch" or "Working Copy"
Branch will have the tool clone the book's git repository. The
choice of the branch (actually any git commit) or of the file
location for the working copy is done in the next menu entry.
Multilib: Four choices: Normal LFS, Multilib with i686 libraries,
multilib with x32 libraries, multilib with all libraries.
It is recommended to use "Normal LFS" unless you know what you
are doing
Build method: two choices: chroot (as in book), boot
Presently, the "boot" method is not implemented, so keep the default.
Add blfs-tools support (see README.BLFS)
This will install the blfs tools onto the newly built system. It
is not the same thing as choosing the BLFS book in the menu, which
will install the blfs tools on the currently running system.
Add custom tools support (see README.CUSTOM)
MENU "General Settings"
Build Directory: the name of the root of the LFS system
This is the equivalent of the LFS variable in the book. Set it
to "/mnt/lfs" if you have followed the book for creating the LFS
partition and mount point.
Retrieve source files: Say y to have jhalfs download the packages
If you say no, you must download the packages yourself and put
them into the /mnt/build_dir/sources directory. Follow book's
chapter 3 instructions.
If you say yes, you'll be asked several other questions:
- Package Archive Directory: Repository of downloaded packages
This directory, which is on the host and should be writable
by the user running the tool, is for storing downloaded packages.
If you keep the default "$SRC_ARCHIVE", you can set this variable
to the absolute path of the repository and export it. Or if the
variable is not set, jhalfs downloads the sources directly to
Instead of using the SRC_ARCHIVE envar, you can also enter the
path of the repository directory into this field.
- Retry on 'connection refused' failure: self explanatory
- Number of retry attempts on download failures: self explanatory
- Download timeout (in seconds): self explanatory
Run the makefile: start the build immediately after running the tool
This is not the preferred method: it is recommended to rather
run "make -C /mnt/build_dir/jhalfs" after the tool has finished
setting up the build. But this may be handy if you are sure everything
is well, and want to leave the tool and the build run without
Rebuild files: clean up the /mnt/build_dir directory
Say n if you want to rerun the tool (to update generated scripts
for example) without removing what has already been done. Otherwise,
say y. Note that there are some guards against removing a directory
containing useful things, but double check that the /mnt/build_dir
directory is really what you want to erase.
MENU "Build Settings"
MENU Parallelism settings
- Use all cores:
If you say y, MAKEFLAGS will be set to "-j$(nproc)" at the
beginning of each script. Other envars are supposed to be passed
from the environment, as done in new books. Note that for old books,
this means the scripts using make or ninja will be run with all
cores, but not when this needs to set special envars like
TESTSUITEFLAGS. You can still define the number of cores used
in next field.
If you say n, you'll be asked for a static number of threads
to use.
- set of cpus to use, or 'all' for all cpus (only if using all cores):
You can define here the cores you want to use. See help for
details. This is the preferred way of reducing the number of cores
rather than using a static thread number.
- Number of parallel `make' jobs (only if not using all cores):
Every occurrence of $(nproc) in new books will be replaced with
the number entered here. Also MAKEFLAGS will be set to "-jN" (where
N is the number entered) at the beginning of each scripts. Furthermore
NINJAJOBS will be set to N in the environment. This allows to run all
books with N threads, except for paarts that need other envars to be
- Build Binutils pass1 without parallelism (Real SBU)
The standard SBU is defined as the time to run the binutils-pass1
build with only one thread. Saying y here allows to get a value for
it. If you say n, the value is not meaningful for SBU measurements.
Run testsuites: say y to run the test suites
You'll have the choice between running all the test suites, or only
those deemed critical (binutils, gmp, mpfr, mpc, and gcc).
Package management: see README.PACKAGE_MANAGEMENT
Create a log of installed files for each package: self explanatory
Strip Installed Binaries/Libraries: use the book instructions for
DO NOT use/display progress_bar (self explanatory)
MENU System configuration
Use a custom fstab file:
If you say y, you'll have to provide a file containing the fstab
for the LFS system. See above "preliminary tasks".
Build the kernel:
If you say y, you'll be asked for a file containing the kernel
configuration. See above "preliminary tasks".
Install non-wide-character ncurses (rarely used nowadays):
If you say y, the system will use instructions in the note on the
ncurses page to install those libraries.
TimeZone: set to the result of "tzselect"
Language: set to the result of the instructions on "The Bash Shell
Startup Files" page.
Install the full set of locales: installs all the locales known to
Groff page size: choice between "A4" and "Letter".
Hostname: self explanatory
Network configuration: various fields for setting network. Look at
chapter 9 for background.
Console configuration: various fields for setting console, as described
in chapter 9.
MENU Advanced features:
Optimization: Optimization settings are done by editing files in the
"optimize" directory. The menu just allows you to choose between applying
optimizations only to the final chapter or to all the book. Say n for
a normal build
Create SBU and disk usage report: self explanatory
Save temporary system work: self explanatory (see help)
Run comparison analysis on final stage: build the system several times
using the preceding one, to test whether it is able to rebuild itself
identically. Don't use normally...
Internal Settings (WARNING: for jhalfs developers only): says it all
Once you have set the parameters and saved the configuration, the script
is launched. Its aim is to extract instructions from the selected book
to generate scripts, and to generate a Makefile, which allows running
the scripts in the right order. The script verifies first that the host
can run itself and build the xLFS system, then validates the configuration
and lists the parameters. At this point, you may choose to quit or to
continue with the listed parameters. The script will then proceed to
generate the Makefile and the build scripts, optionally download
packages, and eventually verify the host prerequisite. If you have
selected "Run the makefile", the command <make> is launched in the
adequate directory, and the build begins. If not, you'll have to run
"make" manually, for example: "make -C /mnt/build_dir/jhalfs", if you
have used the default parameters (see the layout under $BUILDDIR in the
Q&A below).
If you run the jhalfs script directly the only function you can select
is to display the version number by running <./jhalfs -v>
/config/* (needs to be created after cloning since it is an
empty directory initially)
7. FAQ::
Q. "It doesn't work"
A. There are several reasons why it may be so. One possibility is the
following: jhalfs was designed to work against the development versions
of the LFS series of books. Consequently changes in a book sometimes
break older versions of jhalfs. Before you start pulling out your hair,
download the latest version of jhalfs to see if that solves your
problem. Note that it may be the other way around. If you want to build
an old version of the book, you may have to downgrade your jhalfs
Q. "How do I specify the build location?"
A. The original LFS document worked against the well known location
/mnt/lfs. This script automates the build of all of the LFS series of
books and uses a generic location $BUILDDIR with a default value of
/mnt/build_dir. You may change this value to suit your needs.
The layout below $BUILDDIR is as follows.
jhalfs (Makefile, cmd scripts, logs, etc..)
sources (where packages reside)
tools (temporary cross compiler)
FHS dir structure
blfs_root (files to use blfs-tool if selected to install it)
Q. "What is the function of the SRC_ARCHIVE variable?"
A. When jhalfs runs and packages download was selected, it creates a local
copy of the necessary packages in $BUILDDIR/sources by downloading the
files. If the variable SRC_ARCHIVE is defined the software will first
look in this location for the file and, if found, will copy it to
If the files are not found in SRC_ARCHIVE _and_ you have write priv to
the directory any downloaded files will be mirrored there.
Q. "How do I set the SRC_ARCHIVE location?"
A. The best way to set the value of SRC_ARCHIVE is
export SRC_ARCHIVE=/wherever/you/store/downloaded/packages
or you can set the full path in the proper menu entry.
Q. "Why have 2 copies of the files?"
A. The package files must be visible during the chroot phase and this is a
simple and reliable method of doing so. This method also handles the
boot build method where the final build may be done on a separate
Q. "How could I stop the build at a predefined chosen point?"
A. Launch the Makefile manually passing the last numbered target to be build
as the break point. For example:
make BREAKPOINT=84-bash
The build can be stopped also at the end of a top-level build phase by
calling directly the appropriate mk_* target. For example:
make mk_LUSER
See the Makefile to know the proper target names for that book build.
George Boudreau
Manuel Canales Esparcia
Pierre Labastie