MahiroOS-jhalfs/README.BLFS
2013-10-29 15:42:03 +00:00

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1. INTRODUCTION::
If you want to add blfs-tool support into an xLFS base system build,
read the "BLFS_TOOL SUPPORT" section found in the README and be sure
to follow the after-booting installation intructions.
To automate package builds from the BLFS book instructions is a huge
task. Some of the issues are: the BLFS book isn't linear; some package
pages use a custom layout; there are circular dependencies; several
packages can be installed on a non-default prefix; build commands can
change based on what dependencies will be used, etc.
That being said, the goal of the blfs-tool is to help you solve package
dependencies, create build scripts and a Makefile. Not all the auto-generated
build scripts and Makefile will work "as is", thus, as a general rule,
you will need to review and edit the scripts while reading the book.
2. PREREQUISITES::
To use this tool you MUST:
- have experience building BLFS packages
- know how to edit and write shell scripts
- know how a Makefile works
- be able to trace build failures and to find what is causing it
(user error, package bug, BLFS command bug, or jhalfs code bug)
If you do not have the above skills, please don't use this tool.
3. USAGE::
Due to the complexity of the BLFS book, the scripts and Makefile
generation is done in several steps:
3.1 INSTALLED PACKAGES TRACKING SYSTEM::
This tool includes a very simple tracking system to log which packages
have been installed using the tool. It is used to skip installed packages
from target selection menu and to test if an installed package has been
updated in the BLFS book. Do not rely on this feature as a package
management tool.
The tracking system itself is an XML file: instpkg.xml. It is
initialized when <make> is first run in blfs_root. It resides in a
directory, which is created when needed during the process of building
custom tools or blfs dependencies, right after xLFS. You can specify
that directory location in the blfs-tools submenu of jhalfs. You may
need to update permissions and/or ownership of this directory before
using the blfs tool (see README in jhalfs).
The default location of the tracking directory is /var/lib/jhalfs/BLFS.
NB : after the initial build, that directory is only used to contain
instpkg.xml, unless custom tools have been built. In the latter case,
it also contains empty files whose name are $PKG-$VERSION for each
versionned package built. The information about those packages is
included into instpkg.xml the next time the tool is run.
3.2 BLFS_TOOL INSTALLATION::
3.2.1 Normal install
The tools are installed just after the building of xLFS, if the
appropriate options have been selected in the building menu, as per
jhalfs README. If you forgot to select the options and xLFS has been
built, it is possible to go back to selecting the appropriate
BLFS tools options in the jhalfs menu, then tick `Run makefile'
and not `Rebuild files'. You obtain a /blfs_root directory in the
root directory of the new xLFS system, which contains the followings:
blfs-xml/* SVN tree of the selected BLFS book version
lib/constants.inc functions libraries
/func_dependencies for building the dependency tree
menu/* lxdialog and menuconfig source code
xsl/gen_pkg_list.xsl XSL stylesheet to generate the package database
/gen_config.xsl XSL stylesheet to generate the Config.in file
for use in the menuconfig system
/dependencies.xsl XSL stylesheet to generate the dependency list
of a package
/make_book.xsl XSL stylesheet to generate the linear book.xml
/scripts.xsl XSL stylesheet to generate the scriptlets from
book.xml
/bump.xsl XSL stylesheet to generate to update the tracking
file
README.BLFS this file
TODO developers notes (well, not updated often)
gen_pkg_book.sh resolves dependencies and generates linear BLFS
books and build scripts
gen-makefile.sh generates the target Makefile
progress_bar.sh the target Makefile progress bar
gen-special.sh Helper script for generating the package database
Makefile Used by make to update the package database from
the SVN tree, then launch the menuconfig interface,
and run gen_pkg_book.sh based on configuration
settings
packdesc.dtd a simple DTD describing the format of the package
database and the tracking file.
envars.conf envars needed when running the target build scripts
3.2.2 Install to an already running LFS/BLFS system
If you forgot to install the tools when building xLFS, or want to try
the tools, you can just run the install-blfs-tools.sh script. It will
create the above hierarchy in your home directory and intialize the
tracking file. You have first to make sure that the tracking dir exists
and is writable by the user. You may also populate it with (empty) files
whose names are of the form package-version, for installed packages, so
that they are included into the tracking file.
3.3.3 Working files
Several files are generated during the process:
packages.xml auto-generated packages database
Config.in input file for the menu driven choices
configuration file generated by the menuconfig process
dependencies/* files recording the dependency tree
book.xml the linearized book
book-html/* the linearized book rendered in html
scripts/* the scriptlets
From now on, all the work must be done from inside the installation
root directory.
You may move that directory to the $HOME of a non root user, or build
as root from that directory.
3.3 UPDATING BOOK SOURCES::
If you are using the development book version and you want to update
installed packages to the latest version found in that book, you need to
update the XML sources and packages database. This is not necessary if
you just built xLFS, and you can skip to step 3.4.
To do that, run "make update". It may happen that the subversion
version of your building host is older than the version you just
built. This may generate weird errors like "'.' omitted". The easiest
thing to do in that case, is to completely remove the blfs-xml directory
and run "make update". With recent versions of subversion, you can also
run "svn upgrade" from inside the blfs-xml directory.
On the next configuration run, packages already installed but listed
with a new version in the book will be available for target selection
and used to solve dependencies.
3.4 CONFIGURING AND PARSING THE BOOK::
The next step is to create a book and build scripts in dependency
build order for one or several packages.
Run <make> to launch the configuration interface. The main menu contains
two blocks: individual package selection, and build options.
In the build options section, the dependencies level and default packages
used to solve alternatives are set (currently, only for the MTA). You can
also select whether the build will be made as a normal user or as root.
Those settings are saved to be reused in future configuration runs.
Note that you may select as many targets as you want, not just one
as in the previous version of this tool. But we suggest to not select
too many at a time to be able to sort issues!
When you are done with the menu, a few checks occur, and the book is
generated. When circular dependencies are found, a 3 line message is
printed:
A is a dependency of B
C is a dependency of A
A is a dependency of C
and a question:
Do you want to build A first?
This means that the system has found the dependency chain: B->A->C->A.
You have therefore to choose whether A is built before C, or
C before A: the system cannot make that choice (well, maybe in a few
year, with an AI system able to understand the book). If you answer no,
C is built first. If you answer yes, C is put in place of A as a dependency
of B, then the tree dependency restarts from there, that is with the
layout B->C->... You may then hit the case B->C->A->C, for which you
should answer no, unless you want to enter an infinite (human driven)
loop;-)
You end up with a book.xml file which contains the linearized book,
and a rendered HTML, in the directory book-html, which you can browse with
"lynx book-html/index.html" (or with any other browser).
Furthermore, there is a directory "scripts", which contains the generated
scriptlets.
There is also another directory, "dependencies" that contains files
generated while resolving dependencies.
3.5 EDITING BUILD SCRIPTS::
Now it is time to review the generated book and scripts, making any
changes to the scripts necessary to fix generation bugs or to suit your
needs.
Scripts for additional packages (i.e., for non-BLFS packages) can be
easily inserted. For example, if you want to install the external dependency
"bar" before "foo" package and the "foo" script is named "064-z-foo", you
just need to create a "064-y-bar" build script.
Remember, the package tracking system isn't a package management tool
and knows nothing about packages not in the BLFS book.
Also, review and edit envars.conf. This file is used to set global envars
needed by the build scripts.
3.6 CREATING THE MAKEFILE::
When the build scripts are ready to be run, the Makefile can be
created. Create an empty directory (for example "mkdir work") and cd
to that directory. Then run ../gen-makefile.sh
Review the Makefile, and, if all looks sane, start the build by running
"make".
4. GENERATED BUILD SCRIPTS ISSUES::
In this section, known issues with the generated build scripts are
discussed. They are due to build procedures and/or BLFS layout
particularities that we can't handle. In several cases, editing the
build scripts is mandatory.
You may also need to insert some build scripts created by you to resolve
unhandled dependencies and/or to remove some script installing the affected
package by hand.
4.1 BLFS BOOTSCRIPTS::
Normally, bootscript installation should work. On the other hand, the
book does not give instruction for running them, so you might have to
manually insert /etc/init.d/rc.d/<initscript> at some place during the build.
4.2 PACKAGE CONFIGURATION::
For those packages that have a "Configuration" section, you should
edit the build script to fit the needs of your system. Sometimes, the
bash startup files are modified (see for example the instructions for
llvm). The shipped 'envars.conf' contains a line 'source /etc/profile',
which ensures that the proper environment variables are used.
4.3 GCC, JDK, Sane, and KDE-multimedia, freetype2, MesaLib and others
On the pages for those packages, the BLFS book actually has instructions
to download and install two or more packages. You must edit the scripts to
fix this.
We will try to fix some of them, but this may not be possible.
4.4 XORG7
The generated scripts for Xorg7 packages have $SRC_ARCHIVE
support for individual packages, but not for patches nor *.wget and *.md5
files.
If you have previously downloaded the patches, you must edit
the scripts to use your local packages.
The *.wget and *.md5 files should be downladed always from inside
the scripts to be sure that the most current individual packages are
used. Thus don't reuse previously existing ones.
In the script for xorg7-font, be sure to move the fonts directories
symlinks creation to after the "for ... done" loop.
4.5 PATCHES
Please, make sure that all scripts have the commands to download/apply
the required patches. Due to book layout issues, some patches may be
missing.
4.6 ROOT COMMANDS
If building as a normal user (the default setting), be sure that all
commands that require root privileges are run using sudo. Also make sure
necessary root privilege commands are visible in your PATH. Or use
the `Defaults secure_path=' in /etc/sudoers.
For commands necessitating root privileges, the generated scripts wrap
them with the construct:
sudo -E sh << ROOT_EOF
<commands to be executed as root with `$', ``', and `\' escaped>
ROOT_EOF
The -E switch ensures the whole environment is passed to the
commands to be run with root privileges. It is effective only if the
/etc/sudoers file contains `Defaults setenv', or SETENV in the user
attributes. If you think it is a security issue, you may forbid this
flag in /etc/sudoers, but then, you have to un-escape `$' for variables
coming from the environment in the instructions.
Although this construct is rather strong, it can fail in some corner
cases, so carefully review those instructions.
Due to book layout issues, some sudo commands may be missing.
4.7 OTHERS
There may be other issues that we are not aware of. If you find
any, please report it to <alfs-discuss@linuxfromscratch.org>.