Details on this package are located in Section 6.16.2, “Contents of Binutils.”
Copyright © 1999-2018 Gerard Beekmans
Copyright © 1999-2018, Gerard Beekmans
All rights reserved.
This book is licensed under a Creative Commons License.
Computer instructions may be extracted from the book under the MIT License.
Linux® is a registered trademark of Linus Torvalds.
My journey to learn and better understand Linux began over a decade ago, back in 1998. I had just installed my first Linux distribution and had quickly become intrigued with the whole concept and philosophy behind Linux.
There are always many ways to accomplish a single task. The same can be said about Linux distributions. A great many have existed over the years. Some still exist, some have morphed into something else, yet others have been relegated to our memories. They all do things differently to suit the needs of their target audience. Because so many different ways to accomplish the same end goal exist, I began to realize I no longer had to be limited by any one implementation. Prior to discovering Linux, we simply put up with issues in other Operating Systems as you had no choice. It was what it was, whether you liked it or not. With Linux, the concept of choice began to emerge. If you didn't like something, you were free, even encouraged, to change it.
I tried a number of distributions and could not decide on any one. They were great systems in their own right. It wasn't a matter of right and wrong anymore. It had become a matter of personal taste. With all that choice available, it became apparent that there would not be a single system that would be perfect for me. So I set out to create my own Linux system that would fully conform to my personal preferences.
To truly make it my own system, I resolved to compile everything from source code instead of using pre-compiled binary packages. This “perfect” Linux system would have the strengths of various systems without their perceived weaknesses. At first, the idea was rather daunting. I remained committed to the idea that such a system could be built.
After sorting through issues such as circular dependencies and compile-time errors, I finally built a custom-built Linux system. It was fully operational and perfectly usable like any of the other Linux systems out there at the time. But it was my own creation. It was very satisfying to have put together such a system myself. The only thing better would have been to create each piece of software myself. This was the next best thing.
As I shared my goals and experiences with other members of the Linux community, it became apparent that there was a sustained interest in these ideas. It quickly became plain that such custom-built Linux systems serve not only to meet user specific requirements, but also serve as an ideal learning opportunity for programmers and system administrators to enhance their (existing) Linux skills. Out of this broadened interest, the Linux From Scratch Project was born.
This Linux From Scratch book is the central core around that project. It provides the background and instructions necessary for you to design and build your own system. While this book provides a template that will result in a correctly working system, you are free to alter the instructions to suit yourself, which is, in part, an important part of this project. You remain in control; we just lend a helping hand to get you started on your own journey.
I sincerely hope you will have a great time working on your own Linux From Scratch system and enjoy the numerous benefits of having a system that is truly your own.
--
Gerard Beekmans
gerard AT linuxfromscratch D0T org
There are many reasons why you would want to read this book. One of the questions many people raise is, “why go through all the hassle of manually building a Linux system from scratch when you can just download and install an existing one?”
One important reason for this project's existence is to help you learn how a Linux system works from the inside out. Building an LFS system helps demonstrate what makes Linux tick, and how things work together and depend on each other. One of the best things that this learning experience can provide is the ability to customize a Linux system to suit your own unique needs.
Another key benefit of LFS is that it allows you to have more control over the system without relying on someone else's Linux implementation. With LFS, you are in the driver's seat and dictate every aspect of the system.
LFS allows you to create very compact Linux systems. When installing regular distributions, you are often forced to install a great many programs which are probably never used or understood. These programs waste resources. You may argue that with today's hard drive and CPUs, such resources are no longer a consideration. Sometimes, however, you are still constrained by size considerations if nothing else. Think about bootable CDs, USB sticks, and embedded systems. Those are areas where LFS can be beneficial.
Another advantage of a custom built Linux system is security. By compiling the entire system from source code, you are empowered to audit everything and apply all the security patches desired. It is no longer necessary to wait for somebody else to compile binary packages that fix a security hole. Unless you examine the patch and implement it yourself, you have no guarantee that the new binary package was built correctly and adequately fixes the problem.
The goal of Linux From Scratch is to build a complete and usable foundation-level system. If you do not wish to build your own Linux system from scratch, you may nevertheless benefit from the information in this book.
There are too many other good reasons to build your own LFS system to list them all here. In the end, education is by far the most powerful of reasons. As you continue in your LFS experience, you will discover the power that information and knowledge truly bring.
The primary target architectures of LFS are the AMD/Intel x86 (32-bit) and x86_64 (64-bit) CPUs. On the other hand, the instructions in this book are also known to work, with some modifications, with the Power PC and ARM CPUs. To build a system that utilizes one of these CPUs, the main prerequisite, in addition to those on the next few pages, is an existing Linux system such as an earlier LFS installation, Ubuntu, Red Hat/Fedora, SuSE, or other distribution that targets the architecture that you have. Also note that a 32-bit distribution can be installed and used as a host system on a 64-bit AMD/Intel computer.
Some other facts about 64-bit systems need to be added here. When compared to a 32-bit system, the sizes of executable programs are slightly larger and the execution speeds of arbitrary programs are only slightly faster. For example, in a test build of LFS-6.5 on a Core2Duo CPU based system, the following statistics were measured:
Architecture Build Time Build Size
32-bit 198.5 minutes 648 MB
64-bit 190.6 minutes 709 MB
As you can see, the 64-bit build is only 4% faster and is 9% larger than the 32-bit build. The gain from going to a 64-bit system is relatively minimal. Of course, if you have more than 4GB of RAM or want to manipulate data that exceeds 4GB, the advantages of a 64-bit system are substantial.
The above discussion is only appropriate when comparing builds on the same hardware. Modern 64-bit systems are considerably faster than older 64-bit systems and the LFS authors recommend building on a 64-bit system when given a choice.
The default 64-bit build that results from LFS is considered a "pure" 64-bit system. That is, it supports 64-bit executables only. Building a "multi-lib" system requires compiling many applications twice, once for a 32-bit system and once for a 64-bit system. This is not directly supported in LFS because it would interfere with the educational objective of providing the instructions needed for a straightforward base Linux system. You can refer to the Cross Linux From Scratch project for this advanced topic.
The structure of LFS follows Linux standards as closely as possible. The primary standards are:
Linux Standard Base (LSB) Version 5.0
The LSB has four separate standards: Core, Desktop, Runtime Languages, and Imaging. In addition to generic requirements there are also architecture specific requirements. There are also two areas for trial use: Gtk3 and Graphics. LFS attempts to conform to the architectures discussed in the previous section.
Many people do not agree with the requirements of the LSB. The main purpose of defining it is to ensure that proprietary software will be able to be installed and run properly on a compliant system. Since LFS is source based, the user has complete control over what packages are desired and many choose not to install some packages that are specified by the LSB.
Creating a complete LFS system capable of passing the LSB certifications tests is possible, but not without many additional packages that are beyond the scope of LFS. These additional packages have installation instructions in BLFS.
|
LSB Core: |
Bash, Bc, Binutils, Coreutils, Diffutils, File, Findutils, Gawk, Grep, Gzip, M4, Man-DB, Ncurses, Procps, Psmisc, Sed, Shadow, Tar, Util-linux, Zlib |
|
LSB Desktop: |
None |
|
LSB Runtime Languages: |
Perl |
|
LSB Imaging: |
None |
|
LSB Gtk3 and LSB Graphics (Trial Use): |
None |
|
LSB Core: |
At, Batch (a part of At), Cpio, Ed, Fcrontab, Initd-tools, Lsb_release, NSPR, NSS, PAM, Pax, Sendmail (or Postfix or Exim), time |
|
LSB Desktop: |
Alsa, ATK, Cairo, Desktop-file-utils, Freetype, Fontconfig, Gdk-pixbuf, Glib2, GTK+2, Icon-naming-utils, Libjpeg-turbo, Libpng, Libtiff, Libxml2, MesaLib, Pango, Qt4, Xdg-utils, Xorg |
|
LSB Runtime Languages: |
Python, Libxml2, Libxslt |
|
LSB Imaging: |
CUPS, Cups-filters, Ghostscript, SANE |
|
LSB Gtk3 and LSB Graphics (Trial Use): |
GTK+3 |
As stated earlier, the goal of LFS is to build a complete and usable foundation-level system. This includes all packages needed to replicate itself while providing a relatively minimal base from which to customize a more complete system based on the choices of the user. This does not mean that LFS is the smallest system possible. Several important packages are included that are not strictly required. The lists below document the rationale for each package in the book.
Acl
This package contains utilities to administer Access Control Lists, which are used to define more fine-grained discretionary access rights for files and directories.
Attr
This package contains programs for administering extended attributes on filesystem objects.
Autoconf
This package contains programs for producing shell scripts that can automatically configure source code from a developer's template. It is often needed to rebuild a package after updates to the build procedures.
Automake
This package contains programs for generating Make files from a template. It is often needed to rebuild a package after updates to the build procedures.
Bash
This package satisfies an LSB core requirement to provide a Bourne Shell interface to the system. It was chosen over other shell packages because of its common usage and extensive capabilities beyond basic shell functions.
Bc
This package provides an arbitrary precision numeric processing language. It satisfies a requirement needed when building the Linux kernel.
Binutils
This package contains a linker, an assembler, and other tools for handling object files. The programs in this package are needed to compile most of the packages in an LFS system and beyond.
Bison
This package contains the GNU version of yacc (Yet Another Compiler Compiler) needed to build several other LFS programs.
Bzip2
This package contains programs for compressing and decompressing files. It is required to decompress many LFS packages.
Check
This package contains a test harness for other programs. It is only installed in the temporary toolchain.
Coreutils
This package contains a number of essential programs for viewing and manipulating files and directories. These programs are needed for command line file management, and are necessary for the installation procedures of every package in LFS.
DejaGNU
This package contains a framework for testing other programs. It is only installed in the temporary toolchain.
Diffutils
This package contains programs that show the differences between files or directories. These programs can be used to create patches, and are also used in many packages' build procedures.
E2fsprogs
This package contains the utilities for handling the ext2, ext3 and ext4 file systems. These are the most common and thoroughly tested file systems that Linux supports.
Eudev
This package is a device manager. It dynamically controls the entries in the /dev directory as devices are added or removed from the system.
Expat
This package contains a relatively small XML parsing library. It is required by the XML::Parser Perl module.
Expect
This package contains a program for carrying out scripted dialogues with other interactive programs. It is commonly used for testing other packages. It is only installed in the temporary toolchain.
File
This package contains a utility for determining the type of a given file or files. A few packages need it to build.
Findutils
This package contains programs to find files in a file system. It is used in many packages' build scripts.
Flex
This package contains a utility for generating programs that recognize patterns in text. It is the GNU version of the lex (lexical analyzer) program. It is required to build several LFS packages.
Gawk
This package contains programs for manipulating text files. It is the GNU version of awk (Aho-Weinberg-Kernighan). It is used in many other packages' build scripts.
Gcc
This package is the Gnu Compiler Collection. It contains the C and C++ compilers as well as several others not built by LFS.
GDBM
This package contains the GNU Database Manager library. It is used by one other LFS package, Man-DB.
Gettext
This package contains utilities and libraries for internationalization and localization of numerous packages.
Glibc
This package contains the main C library. Linux programs would not run without it.
GMP
This package contains math libraries that provide useful functions for arbitrary precision arithmetic. It is required to build Gcc.
Gperf
This package contains a program that generates a perfect hash function from a key set. It is required for Eudev.
Grep
This package contains programs for searching through files. These programs are used by most packages' build scripts.
Groff
This package contains programs for processing and formatting text. One important function of these programs is to format man pages.
GRUB
This package is the Grand Unified Boot Loader. It is one of several boot loaders available, but is the most flexible.
Gzip
This package contains programs for compressing and decompressing files. It is needed to decompress many packages in LFS and beyond.
Iana-etc
This package provides data for network services and protocols. It is needed to enable proper networking capabilities.
Inetutils
This package contains programs for basic network administration.
Intltool
This package contains tools for extracting translatable strings from source files.
IProute2
This package contains programs for basic and advanced IPv4 and IPv6 networking. It was chosen over the other common network tools package (net-tools) for its IPv6 capabilities.
Kbd
This package contains key-table files, keyboard utilities for non-US keyboards, and a number of console fonts.
Kmod
This package contains programs needed to administer Linux kernel modules.
Less
This package contains a very nice text file viewer that allows scrolling up or down when viewing a file. It is also used by Man-DB for viewing manpages.
Libcap
This package implements the user-space interfaces to the POSIX 1003.1e capabilities available in Linux kernels.
Libffi
This package implements a portable, high level programming interface to various calling conventions. Some programs may not know at the time of compilation what arguments are to be passed to a function. For instance, an interpreter may be told at run-time about the number and types of arguments used to call a given function. Libffi can be used in such programs to provide a bridge from the interpreter program to compiled code.
Libpipeline
The Libpipeline package contains a library for manipulating pipelines of subprocesses in a flexible and convenient way. It is required by the Man-DB package.
Libtool
This package contains the GNU generic library support script. It wraps the complexity of using shared libraries in a consistent, portable interface. It is needed by the test suites in other LFS packages.
Linux Kernel
This package is the Operating System. It is the Linux in the GNU/Linux environment.
M4
This package contains a general text macro processor useful as a build tool for other programs.
Make
This package contains a program for directing the building of packages. It is required by almost every package in LFS.
Man-DB
This package contains programs for finding and viewing man pages. It was chosen instead of the man package due to superior internationalization capabilities. It supplies the man program.
Man-pages
This package contains the actual contents of the basic Linux man pages.
Meson
This package provides a software tool for automating the building of software. The main goal for Meson is to minimize the amount of time that software developers need to spend configuring their build system.
MPC
This package contains functions for the arithmetic of complex numbers. It is required by Gcc.
MPFR
This package contains functions for multiple precision arithmetic. It is required by Gcc.
Ninja
This package contains a small build system with a focus on speed. It is designed to have its input files generated by a higher-level build system, and to run builds as fast as possible.
Ncurses
This package contains libraries for terminal-independent handling of character screens. It is often used to provide cursor control for a menuing system. It is needed by a number of packages in LFS.
Patch
This package contains a program for modifying or creating files by applying a patch file typically created by the diff program. It is needed by the build procedure for several LFS packages.
Perl
This package is an interpreter for the runtime language PERL. It is needed for the installation and test suites of several LFS packages.
Pkg-config
This package provides a program to return meta-data about an installed library or package.
Procps-NG
This package contains programs for monitoring processes. These programs are useful for system administration, and are also used by the LFS Bootscripts.
Psmisc
This package contains programs for displaying information about running processes. These programs are useful for system administration.
Python 3
This package provides an interpreted language that has a design philosophy that emphasizes code readability.
Readline
This package is a set of libraries that offers command-line editing and history capabilities. It is used by Bash.
Sed
This package allows editing of text without opening it in a text editor. It is also needed by most LFS packages' configure scripts.
Shadow
This package contains programs for handling passwords in a secure way.
Sysklogd
This package contains programs for logging system messages, such as those given by the kernel or daemon processes when unusual events occur.
Sysvinit
This package provides the init program, which is the parent of all other processes on the Linux system.
Tar
This package provides archiving and extraction capabilities of virtually all packages used in LFS.
Tcl
This package contains the Tool Command Language used in many test suites in LFS packages. It is only installed in the temporary toolchain.
Texinfo
This package contains programs for reading, writing, and converting info pages. It is used in the installation procedures of many LFS packages.
Util-linux
This package contains miscellaneous utility programs. Among them are utilities for handling file systems, consoles, partitions, and messages.
Vim
This package contains an editor. It was chosen because of its compatibility with the classic vi editor and its huge number of powerful capabilities. An editor is a very personal choice for many users and any other editor could be substituted if desired.
XML::Parser
This package is a Perl module that interfaces with Expat.
XZ Utils
This package contains programs for compressing and decompressing files. It provides the highest compression generally available and is useful for decompressing packages in XZ or LZMA format.
Zlib
This package contains compression and decompression routines used by some programs.
Building an LFS system is not a simple task. It requires a certain level of existing knowledge of Unix system administration in order to resolve problems and correctly execute the commands listed. In particular, as an absolute minimum, you should already have the ability to use the command line (shell) to copy or move files and directories, list directory and file contents, and change the current directory. It is also expected that you have a reasonable knowledge of using and installing Linux software.
Because the LFS book assumes at least this basic level of skill, the various LFS support forums are unlikely to be able to provide you with much assistance in these areas. You will find that your questions regarding such basic knowledge will likely go unanswered or you will simply be referred to the LFS essential pre-reading list.
Before building an LFS system, we recommend reading the following:
Software-Building-HOWTO http://www.tldp.org/HOWTO/Software-Building-HOWTO.html
This is a comprehensive guide to building and installing “generic” Unix software packages under Linux. Although it was written some time ago, it still provides a good summary of the basic techniques needed to build and install software.
Beginner's Guide to Installing from Source http://moi.vonos.net/linux/beginners-installing-from-source/
This guide provides a good summary of basic skills and techniques needed to build software from source code.
To make things easier to follow, there are a few typographical conventions used throughout this book. This section contains some examples of the typographical format found throughout Linux From Scratch.
./configure --prefix=/usr
This form of text is designed to be typed exactly as seen unless otherwise noted in the surrounding text. It is also used in the explanation sections to identify which of the commands is being referenced.
In some cases, a logical line is extended to two or more physical lines with a backslash at the end of the line.
CC="gcc -B/usr/bin/" ../binutils-2.18/configure \ --prefix=/tools --disable-nls --disable-werror
Note that the backslash must be followed by an immediate return. Other whitespace characters like spaces or tab characters will create incorrect results.
install-info: unknown option '--dir-file=/mnt/lfs/usr/info/dir'
This form of text (fixed-width text) shows screen output, usually
as the result of commands issued. This format is also used to
show filenames, such as /etc/ld.so.conf
.
Emphasis
This form of text is used for several purposes in the book. Its main purpose is to emphasize important points or items.
http://www.linuxfromscratch.org/
This format is used for hyperlinks both within the LFS community and to external pages. It includes HOWTOs, download locations, and websites.
cat > $LFS/etc/group << "EOF"
root:x:0:
bin:x:1:
......
EOF
This format is used when creating configuration files. The first
command tells the system to create the file $LFS/etc/group
from whatever is typed on the
following lines until the sequence End Of File (EOF) is
encountered. Therefore, this entire section is generally typed as
seen.
<REPLACED TEXT>
This format is used to encapsulate text that is not to be typed as seen or for copy-and-paste operations.
[OPTIONAL TEXT]
This format is used to encapsulate text that is optional.
passwd(5)
This format is used to refer to a specific manual (man) page. The
number inside parentheses indicates a specific section inside the
manuals. For example, passwd has two man pages. Per
LFS installation instructions, those two man pages will be
located at /usr/share/man/man1/passwd.1
and /usr/share/man/man5/passwd.5
. When the book
uses passwd(5)
it is specifically
referring to /usr/share/man/man5/passwd.5
. man passwd will print the first
man page it finds that matches “passwd”,
which will be /usr/share/man/man1/passwd.1
. For this example,
you will need to run man 5
passwd in order to read the specific page being
referred to. It should be noted that most man pages do not have
duplicate page names in different sections. Therefore,
man <program
name>
is generally sufficient.
This book is divided into the following parts.
Part I explains a few important notes on how to proceed with the LFS installation. This section also provides meta-information about the book.
Part II describes how to prepare for the building process—making a partition, downloading the packages, and compiling temporary tools.
Part III guides the reader through the building of the LFS system—compiling and installing all the packages one by one, setting up the boot scripts, and installing the kernel. The resulting Linux system is the foundation on which other software can be built to expand the system as desired. At the end of this book, there is an easy to use reference listing all of the programs, libraries, and important files that have been installed.
The software used to create an LFS system is constantly being updated and enhanced. Security warnings and bug fixes may become available after the LFS book has been released. To check whether the package versions or instructions in this release of LFS need any modifications to accommodate security vulnerabilities or other bug fixes, please visit http://www.linuxfromscratch.org/lfs/errata/8.2/ before proceeding with your build. You should note any changes shown and apply them to the relevant section of the book as you progress with building the LFS system.
The LFS system will be built by using an already installed Linux distribution (such as Debian, OpenMandriva, Fedora, or openSUSE). This existing Linux system (the host) will be used as a starting point to provide necessary programs, including a compiler, linker, and shell, to build the new system. Select the “development” option during the distribution installation to be able to access these tools.
As an alternative to installing a separate distribution onto your machine, you may wish to use a LiveCD from a commercial distribution.
Chapter 2 of this book describes how to create a new Linux native partition and file system. This is the place where the new LFS system will be compiled and installed. Chapter 3 explains which packages and patches need to be downloaded to build an LFS system and how to store them on the new file system. Chapter 4 discusses the setup of an appropriate working environment. Please read Chapter 4 carefully as it explains several important issues you need be aware of before beginning to work your way through Chapter 5 and beyond.
Chapter 5 explains the installation of a number of packages that will form the basic development suite (or toolchain) which is used to build the actual system in Chapter 6. Some of these packages are needed to resolve circular dependencies—for example, to compile a compiler, you need a compiler.
Chapter 5 also shows you how to build a first pass of the toolchain, including Binutils and GCC (first pass basically means these two core packages will be reinstalled). The next step is to build Glibc, the C library. Glibc will be compiled by the toolchain programs built in the first pass. Then, a second pass of the toolchain will be built. This time, the toolchain will be dynamically linked against the newly built Glibc. The remaining Chapter 5 packages are built using this second pass toolchain. When this is done, the LFS installation process will no longer depend on the host distribution, with the exception of the running kernel.
This effort to isolate the new system from the host distribution may seem excessive. A full technical explanation as to why this is done is provided in Section 5.2, “Toolchain Technical Notes”.
In Chapter 6, the full LFS system is built. The chroot (change root) program is used to enter a virtual environment and start a new shell whose root directory will be set to the LFS partition. This is very similar to rebooting and instructing the kernel to mount the LFS partition as the root partition. The system does not actually reboot, but instead uses chroot because creating a bootable system requires additional work which is not necessary just yet. The major advantage is that “chrooting” allows you to continue using the host system while LFS is being built. While waiting for package compilations to complete, you can continue using your computer as normal.
To finish the installation, the basic system configuration is set up in Chapter 7, and the kernel and boot loader are set up in Chapter 8. Chapter 9 contains information on continuing the LFS experience beyond this book. After the steps in this book have been implemented, the computer will be ready to reboot into the new LFS system.
This is the process in a nutshell. Detailed information on each step is discussed in the following chapters and package descriptions. Items that may seem complicated will be clarified, and everything will fall into place as you embark on the LFS adventure.
Below is a list of package updates made since the previous release of the book.
Upgraded to:
Bash 4.4.18
Binutils-2.30
Check-0.12.0
Coreutils-8.29
DejaGNU-1.6.1
Eudev-3.2.5
E2fsprogs-1.43.9
Expat-2.2.5
Expect-5.45.4
File-5.32
Gawk-4.2.0
GCC-7.3.0
GDBM-1.14.1
Glibc-2.27
Gzip-1.9
IPRoute2-4.15.0
Kmod-25
Less-530
Libelf-0.170
Libpipeline-1.5.0
Linux-4.15.3
Man-DB-2.8.1
Man-pages-4.15
MPC-1.1.0
MPFR-4.0.1
Ncurses-6.1
Patch-2.7.6
Perl-5.26.1
Tar-1.30
Tcl-core-8.6.8
Texinfo-6.5
Tzdata-2018c
Util-Linux-2.31.1
Added:
Libffi-3.2.1
Openssl-1.1.0g
Python-3.6.4
Ninja-1.8.2
Meson-0.44.0
Removed:
bash-4.4-upstream_fixes-1.patch
This is version 8.2 of the Linux From Scratch book, dated March 2, 2018. If this book is more than six months old, a newer and better version is probably already available. To find out, please check one of the mirrors via http://www.linuxfromscratch.org/mirrors.html.
Below is a list of changes made since the previous release of the book.
Changelog Entries:
2018-03-02
[bdubbs] - LFS-8.2 released.
2018-02-26
2018-02-14
[bdubbs] - Update to linux-4.15.3. Fixes #4218.
2018-02-09
[bdubbs] - Update to man-db-2.8.1. Fixes #4216.
2018-02-09
2018-02-05
2018-02-02
2018-01-30
2018-01-28
2018-01-13
[bdubbs] - Add warnings about mounting /mnt/lfs and the export of $LFS if restarting the host system. Add comments to automate those actions.
2018-01-13
2018-01-13
[dj] - Simplify and correct Libelf instructions.
2018-01-12
[dj] - Add Libelf (Elfutils) 0.170.
[dj] - Update to Linux-4.14.13. Fixes #4195.
2018-01-11
2018-01-06
2018-01-01
[bdubbs] - Add comments to the kernel section to change the unwinder option. Fixes #4186.
[bdubbs] - Update to linux-4.14.10. Fixes #4184.
[bdubbs] - Update to coreutils-8.29. Fixes #4189.
[bdubbs] - Remove old footer from non-chunks book. Fixes #4188.
[bdubbs] - Make spacing between "Chapter" and digit non breaking. Fixes #4187.
2017-12-26
[bdubbs] - Update to tcl-8.6.8. Fixes #4183.
2017-12-25
2017-12-22
[bdubbs] - Update to linux-4.14.8. Fixes #4177.
2017-12-22
[dj] - Update to util-linux-2.31.1. Fixes #4176.
2017-12-19
2017-12-03
2017-11-26
[bdubbs] - Prevent installation of unneeded gawk files.
2017-11-17
2017-11-11
[dj] - Update to linux-4.13.12. Fixes #4163.
2017-11-06
2017-10-28
2017-10-27
[bdubbs] - Update rule in 83-cdrom-symlinks.rules in udev-lfs tarball.
2017-10-20
2017-10-15
[bdubbs] - Add optional patch to ninja.
2017-10-14
2017-09-23
2017-09-22
[bdubbs] - Update to util-linux 2.30.2. Fixes #4139.
[bdubbs] - Update to man-pages-4.13. Fixes #4138.
[bdubbs] - Update to texinfo-6.5. Fixes #4137.
[bdubbs] - Update to mpfr-3.1.6. Fixes #4136.
[bdubbs] - Update to iproute2-4.13.0. Fixes #4135.
[bdubbs] - Update to eudev-3.2.3. Fixes #4133.
[bdubbs] - Update to linux-4.13.3. Fixes #4134.
2017-09-02
2017-09-01
[bdubbs] - LFS-8.1 released.
If during the building of the LFS system you encounter any errors, have any questions, or think there is a typo in the book, please start by consulting the Frequently Asked Questions (FAQ) that is located at http://www.linuxfromscratch.org/faq/.
The linuxfromscratch.org
server
hosts a number of mailing lists used for the development of
the LFS project. These lists include the main development and
support lists, among others. If the FAQ does not solve the
problem you are having, the next step would be to search the
mailing lists at http://www.linuxfromscratch.org/search.html.
For information on the different lists, how to subscribe, archive locations, and additional information, visit http://www.linuxfromscratch.org/mail.html.
Several members of the LFS community offer assistance on
Internet Relay Chat (IRC). Before using this support, please
make sure that your question is not already answered in the
LFS FAQ or the mailing list archives. You can find the IRC
network at irc.freenode.net
. The
support channel is named #LFS-support.
The LFS project has a number of world-wide mirrors to make accessing the website and downloading the required packages more convenient. Please visit the LFS website at http://www.linuxfromscratch.org/mirrors.html for a list of current mirrors.
If an issue or a question is encountered while working through this book, please check the FAQ page at http://www.linuxfromscratch.org/faq/#generalfaq. Questions are often already answered there. If your question is not answered on this page, try to find the source of the problem. The following hint will give you some guidance for troubleshooting: http://www.linuxfromscratch.org/hints/downloads/files/errors.txt.
If you cannot find your problem listed in the FAQ, search the mailing lists at http://www.linuxfromscratch.org/search.html.
We also have a wonderful LFS community that is willing to offer assistance through the mailing lists and IRC (see the Section 1.4, “Resources” section of this book). However, we get several support questions every day and many of them can be easily answered by going to the FAQ and by searching the mailing lists first. So, for us to offer the best assistance possible, you need to do some research on your own first. That allows us to focus on the more unusual support needs. If your searches do not produce a solution, please include all relevant information (mentioned below) in your request for help.
Apart from a brief explanation of the problem being experienced, the essential things to include in any request for help are:
The version of the book being used (in this case 8.2 )
The host distribution and version being used to create LFS
The output from the Host System Requirements script
The package or section the problem was encountered in
The exact error message or symptom being received
Note whether you have deviated from the book at all
Deviating from this book does not mean that we will not help you. After all, LFS is about personal preference. Being upfront about any changes to the established procedure helps us evaluate and determine possible causes of your problem.
If something goes wrong while running the configure script, review
the config.log
file. This file
may contain errors encountered during configure which were not
printed to the screen. Include the relevant lines if you need to ask
for help.
Both the screen output and the contents of various files are useful in determining the cause of compilation problems. The screen output from the configure script and the make run can be helpful. It is not necessary to include the entire output, but do include enough of the relevant information. Below is an example of the type of information to include from the screen output from make:
gcc -DALIASPATH=\"/mnt/lfs/usr/share/locale:.\"
-DLOCALEDIR=\"/mnt/lfs/usr/share/locale\"
-DLIBDIR=\"/mnt/lfs/usr/lib\"
-DINCLUDEDIR=\"/mnt/lfs/usr/include\" -DHAVE_CONFIG_H -I. -I.
-g -O2 -c getopt1.c
gcc -g -O2 -static -o make ar.o arscan.o commands.o dir.o
expand.o file.o function.o getopt.o implicit.o job.o main.o
misc.o read.o remake.o rule.o signame.o variable.o vpath.o
default.o remote-stub.o version.o opt1.o
-lutil job.o: In function `load_too_high':
/lfs/tmp/make-3.79.1/job.c:1565: undefined reference
to `getloadavg'
collect2: ld returned 1 exit status
make[2]: *** [make] Error 1
make[2]: Leaving directory `/lfs/tmp/make-3.79.1'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/lfs/tmp/make-3.79.1'
make: *** [all-recursive-am] Error 2
In this case, many people would just include the bottom section:
make [2]: *** [make] Error 1
This is not enough information to properly diagnose the problem because it only notes that something went wrong, not what went wrong. The entire section, as in the example above, is what should be saved because it includes the command that was executed and the associated error message(s).
An excellent article about asking for help on the Internet is available online at http://catb.org/~esr/faqs/smart-questions.html. Read and follow the hints in this document to increase the likelihood of getting the help you need.
In this chapter, the host tools needed for building LFS are checked and, if necessary, installed. Then a partition which will host the LFS system is prepared. We will create the partition itself, create a file system on it, and mount it.
Your host system should have the following software with the minimum versions indicated. This should not be an issue for most modern Linux distributions. Also note that many distributions will place software headers into separate packages, often in the form of “<package-name>-devel” or “<package-name>-dev”. Be sure to install those if your distribution provides them.
Earlier versions of the listed software packages may work, but have not been tested.
Bash-3.2 (/bin/sh should be a symbolic or hard link to bash)
Binutils-2.17 (Versions greater than 2.30 are not recommended as they have not been tested)
Bison-2.3 (/usr/bin/yacc should be a link to bison or small script that executes bison)
Bzip2-1.0.4
Coreutils-6.9
Diffutils-2.8.1
Findutils-4.2.31
Gawk-4.0.1 (/usr/bin/awk should be a link to gawk)
GCC-4.7 including the C++ compiler, g++ (Versions greater than 7.3.0 are not recommended as they have not been tested)
Glibc-2.11 (Versions greater than 2.27 are not recommended as they have not been tested)
Grep-2.5.1a
Gzip-1.3.12
Linux Kernel-3.2
The reason for the kernel version requirement is that we specify that version when building glibc in Chapter 6 at the recommendation of the developers. It is also required by udev.
If the host kernel is earlier than 3.2 you will need to replace the kernel with a more up to date version. There are two ways you can go about this. First, see if your Linux vendor provides a 3.2 or later kernel package. If so, you may wish to install it. If your vendor doesn't offer an acceptable kernel package, or you would prefer not to install it, you can compile a kernel yourself. Instructions for compiling the kernel and configuring the boot loader (assuming the host uses GRUB) are located in Chapter 8.
M4-1.4.10
Make-3.81
Patch-2.5.4
Perl-5.8.8
Sed-4.1.5
Tar-1.22
Texinfo-4.7
Xz-5.0.0
Note that the symlinks mentioned above are required to build an LFS system using the instructions contained within this book. Symlinks that point to other software (such as dash, mawk, etc.) may work, but are not tested or supported by the LFS development team, and may require either deviation from the instructions or additional patches to some packages.
 That is, the instructions assume that the system will not be shut down during the process. That does not mean that the system has to be done in one sitting. The issue is that certain procedures have to be re-accomplished after a reboot if resuming LFS at different points.
These chapters are accomplished on the host system. When restarting, be careful of the following:
Procedures done as the root user after Section 2.4 need to have the LFS environment variable set FOR THE ROOT USER.
The /mnt/lfs partition must be mounted.
ALL instructions in Chapter 5 must be done by user lfs. A su - lfs needs to be done before any task in Chapter 5.
The procedures in Section 5.3, “General Compilation Instructions” are critical. If there is any doubt about installing a package, ensure any previously expanded tarballs are removed, re-extract the package files, and complete all instructions in that section.
The /mnt/lfs partition must be mounted.
When entering chroot, the LFS environment variable must be set for root. The LFS variable is not used otherwise.
The virtual file systems must be mounted. This can be done before or after entering chroot by changing to a host virtual terminal and, as root, running the commands in Section 6.2.2, “Mounting and Populating /dev” and Section 6.2.3, “Mounting Virtual Kernel File Systems”.
Like most other operating systems, LFS is usually installed on a dedicated partition. The recommended approach to building an LFS system is to use an available empty partition or, if you have enough unpartitioned space, to create one.
A minimal system requires a partition of around 6 gigabytes (GB). This is enough to store all the source tarballs and compile the packages. However, if the LFS system is intended to be the primary Linux system, additional software will probably be installed which will require additional space. A 20 GB partition is a reasonable size to provide for growth. The LFS system itself will not take up this much room. A large portion of this requirement is to provide sufficient free temporary storage as well as for adding additional capabilities after LFS is complete. Additionally, compiling packages can require a lot of disk space which will be reclaimed after the package is installed.
Because there is not always enough Random Access Memory (RAM)
available for compilation processes, it is a good idea to use a
small disk partition as swap
space. This is used by the kernel to store seldom-used data and
leave more memory available for active processes. The
swap
partition for an LFS
system can be the same as the one used by the host system, in
which case it is not necessary to create another one.
Start a disk partitioning program such as cfdisk or fdisk with a command line
option naming the hard disk on which the new partition will be
created—for example /dev/sda
for the primary Integrated Drive
Electronics (IDE) disk. Create a Linux native partition and a
swap
partition, if needed.
Please refer to cfdisk(8)
or
fdisk(8)
if you do not yet know
how to use the programs.
For experienced users, other partitioning schemes are possible. The new LFS system can be on a software RAID array or an LVM logical volume. However, some of these options require an initramfs, which is an advanced topic. These partitioning methodologies are not recommended for first time LFS users.
Remember the designation of the new partition (e.g.,
sda5
). This book will refer to
this as the LFS partition. Also remember the designation of the
swap
partition. These names
will be needed later for the /etc/fstab
file.
Requests for advice on system partitioning are often posted on the LFS mailing lists. This is a highly subjective topic. The default for most distributions is to use the entire drive with the exception of one small swap partition. This is not optimal for LFS for several reasons. It reduces flexibility, makes sharing of data across multiple distributions or LFS builds more difficult, makes backups more time consuming, and can waste disk space through inefficient allocation of file system structures.
A root LFS partition (not to be confused with the
/root
directory) of ten
gigabytes is a good compromise for most systems. It
provides enough space to build LFS and most of BLFS, but is
small enough so that multiple partitions can be easily
created for experimentation.
Most distributions automatically create a swap partition. Generally the recommended size of the swap partition is about twice the amount of physical RAM, however this is rarely needed. If disk space is limited, hold the swap partition to two gigabytes and monitor the amount of disk swapping.
Swapping is never good. Generally you can tell if a system is swapping by just listening to disk activity and observing how the system reacts to commands. The first reaction to swapping should be to check for an unreasonable command such as trying to edit a five gigabyte file. If swapping becomes a normal occurrence, the best solution is to purchase more RAM for your system.
If the boot disk has been partitioned with a GUID Partition Table (GPT), then a small, typically 1 MB, partition must be created if it does not already exist. This partition is not formatted, but must be available for GRUB to use during installation of the boot loader. This partition will normally be labeled 'BIOS Boot' if using fdisk or have a code of EF02 if using gdisk.
The Grub Bios partition must be on the drive that the BIOS uses to boot the system. This is not necessarily the same drive where the LFS root partition is located. Disks on a system may use different partition table types. The requirement for this partition depends only on the partition table type of the boot disk.
There are several other partitions that are not required, but should be considered when designing a disk layout. The following list is not comprehensive, but is meant as a guide.
/boot – Highly recommended. Use this partition to store kernels and other booting information. To minimize potential boot problems with larger disks, make this the first physical partition on your first disk drive. A partition size of 100 megabytes is quite adequate.
/home – Highly recommended. Share your home directory and user customization across multiple distributions or LFS builds. The size is generally fairly large and depends on available disk space.
/usr – A separate /usr partition is generally used if providing a server for a thin client or diskless workstation. It is normally not needed for LFS. A size of five gigabytes will handle most installations.
/opt – This directory is most useful for BLFS where multiple installations of large packages like Gnome or KDE can be installed without embedding the files in the /usr hierarchy. If used, 5 to 10 gigabytes is generally adequate.
/tmp – A separate /tmp directory is rare, but useful if configuring a thin client. This partition, if used, will usually not need to exceed a couple of gigabytes.
/usr/src – This partition is very useful for providing a location to store BLFS source files and share them across LFS builds. It can also be used as a location for building BLFS packages. A reasonably large partition of 30-50 gigabytes allows plenty of room.
Any separate partition that you want automatically mounted
upon boot needs to be specified in the /etc/fstab
. Details about how to specify
partitions will be discussed in Section 8.2,
“Creating the /etc/fstab File”.
Now that a blank partition has been set up, the file system can be created. LFS can use any file system recognized by the Linux kernel, but the most common types are ext3 and ext4. The choice of file system can be complex and depends on the characteristics of the files and the size of the partition. For example:
is suitable for small partitions that are updated infrequently such as /boot.
is an upgrade to ext2 that includes a journal to help recover the partition's status in the case of an unclean shutdown. It is commonly used as a general purpose file system.
is the latest version of the ext file system family of partition types. It provides several new capabilities including nano-second timestamps, creation and use of very large files (16 TB), and speed improvements.
Other file systems, including FAT32, NTFS, ReiserFS, JFS, and XFS are useful for specialized purposes. More information about these file systems can be found at http://en.wikipedia.org/wiki/Comparison_of_file_systems.
LFS assumes that the root file system (/) is of type ext4. To
create an ext4
file system on
the LFS partition, run the following:
mkfs -v -t ext4 /dev/<xxx>
If you are using an existing swap
partition, there is no need to format
it. If a new swap
partition was
created, it will need to be initialized with this command:
mkswap /dev/<yyy>
Replace <yyy>
with the name of the swap
partition.
Throughout this book, the environment variable LFS
will be used several times. You should
ensure that this variable is always defined throughout the LFS
build process. It should be set to the name of the directory
where you will be building your LFS system - we will use
/mnt/lfs
as an example, but the
directory choice is up to you. If you are building LFS on a
separate partition, this directory will be the mount point for
the partition. Choose a directory location and set the variable
with the following command:
export LFS=/mnt/lfs
Having this variable set is beneficial in that commands such as mkdir -v $LFS/tools can be typed literally. The shell will automatically replace “$LFS” with “/mnt/lfs” (or whatever the variable was set to) when it processes the command line.
Do not forget to check that LFS
is
set whenever you leave and reenter the current working
environment (such as when doing a su to root
or another user). Check that the
LFS
variable is set up properly
with:
echo $LFS
Make sure the output shows the path to your LFS system's
build location, which is /mnt/lfs
if the provided example was
followed. If the output is incorrect, use the command given
earlier on this page to set $LFS
to the correct directory name.
One way to ensure that the LFS
variable is always set is to edit the .bash_profile
file in both your personal
home directory and in /root/.bash_profile
and enter the export
command above. In addition, the shell specified in the
/etc/passwd
file for all users
that need the LFS
variable needs
to be bash to ensure that the /root/.bash_profile
file is incorporated as
a part of the login process.
Another consideration is the method that is used to log into
the host system. If logging in through a graphical display
manager, the user's .bash_profile
is not normally used when a
virtual terminal is started. In this case, add the export
command to the .bashrc
file for
the user and root. In addition, some distributions have
instructions to not run the .bashrc
instructions in a non-interactive
bash invocation. Be sure to add the export command before the
test for non-interactive use.
Now that a file system has been created, the partition needs to
be made accessible. In order to do this, the partition needs to
be mounted at a chosen mount point. For the purposes of this
book, it is assumed that the file system is mounted under the
directory specified by the LFS
environment variable as described in the previous section.
Create the mount point and mount the LFS file system by running:
mkdir -pv $LFS
mount -v -t ext4 /dev/<xxx>
$LFS
Replace <xxx>
with the designation of the LFS partition.
If using multiple partitions for LFS (e.g., one for
/
and another for /usr
), mount them using:
mkdir -pv $LFS mount -v -t ext4 /dev/<xxx>
$LFS mkdir -v $LFS/usr mount -v -t ext4 /dev/<yyy>
$LFS/usr
Replace <xxx>
and <yyy>
with
the appropriate partition names.
Ensure that this new partition is not mounted with permissions
that are too restrictive (such as the nosuid
or nodev
options). Run the mount command without any
parameters to see what options are set for the mounted LFS
partition. If nosuid
and/or
nodev
are set, the partition will
need to be remounted.
The above instructions assume that you will not be restarting your computer throughout the LFS process. If you shut down your system, you will either need to remount the LFS partition each time you restart the build process or modify your host system's /etc/fstab file to automatically remount it upon boot. For example:
/dev/<xxx>
/mnt/lfs ext4 defaults 1 1
If you use additional optional partitions, be sure to add them also.
If you are using a swap
partition, ensure that it is enabled using the swapon command:
/sbin/swapon -v /dev/<zzz>
Replace <zzz>
with the name of the swap
partition.
Now that there is an established place to work, it is time to download the packages.
This chapter includes a list of packages that need to be downloaded in order to build a basic Linux system. The listed version numbers correspond to versions of the software that are known to work, and this book is based on their use. We highly recommend against using newer versions because the build commands for one version may not work with a newer version. The newest package versions may also have problems that require work-arounds. These work-arounds will be developed and stabilized in the development version of the book.
Download locations may not always be accessible. If a download location has changed since this book was published, Google (http://www.google.com/) provides a useful search engine for most packages. If this search is unsuccessful, try one of the alternative means of downloading discussed at http://www.linuxfromscratch.org/lfs/packages.html#packages.
Downloaded packages and patches will need to be stored
somewhere that is conveniently available throughout the entire
build. A working directory is also required to unpack the
sources and build them. $LFS/sources
can be used both as the place to
store the tarballs and patches and as a working directory. By
using this directory, the required elements will be located on
the LFS partition and will be available during all stages of
the building process.
To create this directory, execute the following command, as
user root
, before starting the
download session:
mkdir -v $LFS/sources
Make this directory writable and sticky. “Sticky” means that even if multiple users have write permission on a directory, only the owner of a file can delete the file within a sticky directory. The following command will enable the write and sticky modes:
chmod -v a+wt $LFS/sources
An easy way to download all of the packages and patches is by using wget-list as an input to wget. For example:
wget --input-file=wget-list --continue --directory-prefix=$LFS/sources
Additionally, starting with LFS-7.0, there is a separate file,
md5sums, which can be
used to verify that all the correct packages are available
before proceeding.  The site administrators of the master download location occasionally remove older versions when new ones are released. An alternative download location that may have the correct version available can also be found at: http://www.linuxfromscratch.org/lfs/download.html#ftp.

 The latest available 4.15.x kernel version should be used, unless the errata page says otherwise.
For users with limited speed or expensive bandwidth who wish to update the Linux kernel, a baseline version of the package and patches can be downloaded separately. This may save some time or cost for a subsequent patch level upgrade within a minor release.
 These patches correct any mistakes in the packages that should be fixed by the maintainer. The patches also make small modifications to make the packages easier to work with. The following patches will be needed to build an LFS system:
Download: http://www.linuxfromscratch.org/patches/lfs/8.2/bzip2-1.0.6-install_docs-1.patch
MD5 sum: 6a5ac7e89b791aae556de0f745916f7f
Download: http://www.linuxfromscratch.org/patches/lfs/8.2/coreutils-8.29-i18n-1.patch
MD5 sum: a9404fb575dfd5514f3c8f4120f9ca7d
Download: http://www.linuxfromscratch.org/patches/lfs/8.2/glibc-2.27-fhs-1.patch
MD5 sum: 9a5997c3452909b1769918c759eff8a2
Download: http://www.linuxfromscratch.org/patches/lfs/8.2/kbd-2.0.4-backspace-1.patch
MD5 sum: f75cca16a38da6caa7d52151f7136895
Download: http://www.linuxfromscratch.org/patches/lfs/8.2/ninja-1.8.2-add_NINJAJOBS_var-1.patch
MD5 sum: f537a633532492e805aa342fa869ca45
Download: http://www.linuxfromscratch.org/patches/lfs/8.2/sysvinit-2.88dsf-consolidated-1.patch
MD5 sum: 0b7b5ea568a878fdcc4057b2bf36e5cb
Total size of these patches: about 190.8 KB
In addition to the above required patches, there exist a number of optional patches created by the LFS community. These optional patches solve minor problems or enable functionality that is not enabled by default. Feel free to peruse the patches database located at http://www.linuxfromscratch.org/patches/downloads/ and acquire any additional patches to suit your system needs.
In this chapter, we will perform a few additional tasks to
prepare for building the temporary system. We will create a
directory in $LFS
for the
installation of the temporary tools, add an unprivileged user
to reduce risk, and create an appropriate build environment for
that user. We will also explain the unit of time we use to
measure how long LFS packages take to build, or “SBUs”,
and give some information about package test suites.
All programs compiled in Chapter 5
will be installed under $LFS/tools
to keep them separate from the
programs compiled in Chapter 6.
The programs compiled here are temporary tools and will not be
a part of the final LFS system. By keeping these programs in a
separate directory, they can easily be discarded later after
their use. This also prevents these programs from ending up in
the host production directories (easy to do by accident in
Chapter 5).
Create the required directory by running the following as
root
:
mkdir -v $LFS/tools
The next step is to create a /tools
symlink on the host system. This will
point to the newly-created directory on the LFS partition. Run
this command as root
as well:
ln -sv $LFS/tools /
The above command is correct. The ln command has a few
syntactic variations, so be sure to check info coreutils ln and
ln(1)
before reporting what you
may think is an error.
The created symlink enables the toolchain to be compiled so
that it always refers to /tools
,
meaning that the compiler, assembler, and linker will work both
in Chapter 5 (when we are still using some tools from the
host) and in the next (when we are “chrooted” to the LFS partition).
When logged in as user root
,
making a single mistake can damage or destroy a system.
Therefore, we recommend building the packages in this chapter
as an unprivileged user. You could use your own user name, but
to make it easier to set up a clean working environment, create
a new user called lfs
as a
member of a new group (also named lfs
) and use this user during the
installation process. As root
,
issue the following commands to add the new user:
groupadd lfs useradd -s /bin/bash -g lfs -m -k /dev/null lfs
The meaning of the command line options:
-s
/bin/bash
This makes bash the default shell
for user lfs
.
-g
lfs
This option adds user lfs
to group lfs
.
-m
This creates a home directory for lfs
.
-k
/dev/null
This parameter prevents possible copying of files from a
skeleton directory (default is /etc/skel
) by changing the input
location to the special null device.
lfs
This is the actual name for the created group and user.
To log in as lfs
(as opposed to
switching to user lfs
when
logged in as root
, which does
not require the lfs
user to
have a password), give lfs
a
password:
passwd lfs
Grant lfs
full access to
$LFS/tools
by making lfs
the directory owner:
chown -v lfs $LFS/tools
If a separate working directory was created as suggested, give
user lfs
ownership of this
directory:
chown -v lfs $LFS/sources
Next, login as user lfs
. This
can be done via a virtual console, through a display manager,
or with the following substitute user command:
su - lfs
The “-
” instructs
su to start a
login shell as opposed to a non-login shell. The difference
between these two types of shells can be found in detail in
bash(1)
and info bash.
Set up a good working environment by creating two new startup
files for the bash shell. While logged in
as user lfs
, issue the
following command to create a new .bash_profile
:
cat > ~/.bash_profile << "EOF"
exec env -i HOME=$HOME TERM=$TERM PS1='\u:\w\$ ' /bin/bash
EOF
When logged on as user lfs
, the
initial shell is usually a login shell which reads the
/etc/profile
of the host
(probably containing some settings and environment variables)
and then .bash_profile
. The
exec env
-i.../bin/bash command in the .bash_profile
file replaces the running shell
with a new one with a completely empty environment, except for
the HOME
, TERM
, and PS1
variables. This ensures that no unwanted and potentially
hazardous environment variables from the host system leak into
the build environment. The technique used here achieves the
goal of ensuring a clean environment.
The new instance of the shell is a non-login shell, which does not read
the /etc/profile
or .bash_profile
files, but rather reads the
.bashrc
file instead. Create the
.bashrc
file now:
cat > ~/.bashrc << "EOF"
set +h
umask 022
LFS=/mnt/lfs
LC_ALL=POSIX
LFS_TGT=$(uname -m)-lfs-linux-gnu
PATH=/tools/bin:/bin:/usr/bin
export LFS LC_ALL LFS_TGT PATH
EOF
The set +h
command turns off bash's hash function. Hashing
is ordinarily a useful feature—bash uses a hash table to
remember the full path of executable files to avoid searching
the PATH
time and again to find the
same executable. However, the new tools should be used as soon
as they are installed. By switching off the hash function, the
shell will always search the PATH
when a program is to be run. As such, the shell will find the
newly compiled tools in $LFS/tools
as soon as they are available
without remembering a previous version of the same program in a
different location.
Setting the user file-creation mask (umask) to 022 ensures that
newly created files and directories are only writable by their
owner, but are readable and executable by anyone (assuming
default modes are used by the open(2)
system call, new files will end up
with permission mode 644 and directories with mode 755).
The LFS
variable should be set to
the chosen mount point.
The LC_ALL
variable controls the
localization of certain programs, making their messages follow
the conventions of a specified country. Setting LC_ALL
to “POSIX”
or “C” (the two are equivalent) ensures
that everything will work as expected in the chroot
environment.
The LFS_TGT
variable sets a
non-default, but compatible machine description for use when
building our cross compiler and linker and when cross compiling
our temporary toolchain. More information is contained in
Section 5.2,
“Toolchain Technical Notes”.
By putting /tools/bin
ahead of
the standard PATH
, all the programs
installed in Chapter 5
are picked up by the shell immediately after their
installation. This, combined with turning off hashing, limits
the risk that old programs are used from the host when the same
programs are available in the chapter 5 environment.
Finally, to have the environment fully prepared for building the temporary tools, source the just-created user profile:
source ~/.bash_profile
Many people would like to know beforehand approximately how long it takes to compile and install each package. Because Linux From Scratch can be built on many different systems, it is impossible to provide accurate time estimates. The biggest package (Glibc) will take approximately 20 minutes on the fastest systems, but could take up to three days on slower systems! Instead of providing actual times, the Standard Build Unit (SBU) measure will be used instead.
The SBU measure works as follows. The first package to be compiled from this book is Binutils in Chapter 5. The time it takes to compile this package is what will be referred to as the Standard Build Unit or SBU. All other compile times will be expressed relative to this time.
For example, consider a package whose compilation time is 4.5 SBUs. This means that if a system took 10 minutes to compile and install the first pass of Binutils, it will take approximately 45 minutes to build this example package. Fortunately, most build times are shorter than the one for Binutils.
In general, SBUs are not entirely accurate because they depend on many factors, including the host system's version of GCC. They are provided here to give an estimate of how long it might take to install a package, but the numbers can vary by as much as dozens of minutes in some cases.
For many modern systems with multiple processors (or cores) the compilation time for a package can be reduced by performing a "parallel make" by either setting an environment variable or telling the make program how many processors are available. For instance, a Core2Duo can support two simultaneous processes with:
export MAKEFLAGS='-j 2'
or just building with:
make -j2
When multiple processors are used in this way, the SBU units in the book will vary even more than they normally would. In some cases, the make step will simply fail. Analyzing the output of the build process will also be more difficult because the lines of different processes will be interleaved. If you run into a problem with a build step, revert back to a single processor build to properly analyze the error messages.
Most packages provide a test suite. Running the test suite for a newly built package is a good idea because it can provide a “sanity check” indicating that everything compiled correctly. A test suite that passes its set of checks usually proves that the package is functioning as the developer intended. It does not, however, guarantee that the package is totally bug free.
Some test suites are more important than others. For example, the test suites for the core toolchain packages—GCC, Binutils, and Glibc—are of the utmost importance due to their central role in a properly functioning system. The test suites for GCC and Glibc can take a very long time to complete, especially on slower hardware, but are strongly recommended.
Experience has shown that there is little to be gained from running the test suites in Chapter 5. There can be no escaping the fact that the host system always exerts some influence on the tests in that chapter, often causing inexplicable failures. Because the tools built in Chapter 5 are temporary and eventually discarded, we do not recommend running the test suites in Chapter 5 for the average reader. The instructions for running those test suites are provided for the benefit of testers and developers, but they are strictly optional.
A common issue with running the test suites for Binutils and
GCC is running out of pseudo terminals (PTYs). This can result
in a high number of failing tests. This may happen for several
reasons, but the most likely cause is that the host system does
not have the devpts
file system
set up correctly. This issue is discussed in greater detail at
http://www.linuxfromscratch.org/lfs/faq.html#no-ptys.
Sometimes package test suites will fail, but for reasons which the developers are aware of and have deemed non-critical. Consult the logs located at http://www.linuxfromscratch.org/lfs/build-logs/8.2/ to verify whether or not these failures are expected. This site is valid for all tests throughout this book.
This chapter shows how to build a minimal Linux system. This system will contain just enough tools to start constructing the final LFS system in Chapter 6 and allow a working environment with more user convenience than a minimum environment would.
There are two steps in building this minimal system. The first step is to build a new and host-independent toolchain (compiler, assembler, linker, libraries, and a few useful utilities). The second step uses this toolchain to build the other essential tools.
The files compiled in this chapter will be installed under the
$LFS/tools
directory to keep them
separate from the files installed in the next chapter and the
host production directories. Since the packages compiled here
are temporary, we do not want them to pollute the soon-to-be
LFS system.
This section explains some of the rationale and technical details behind the overall build method. It is not essential to immediately understand everything in this section. Most of this information will be clearer after performing an actual build. This section can be referred to at any time during the process.
The overall goal of Chapter 5 is to produce a temporary area that contains a known-good set of tools that can be isolated from the host system. By using chroot, the commands in the remaining chapters will be contained within that environment, ensuring a clean, trouble-free build of the target LFS system. The build process has been designed to minimize the risks for new readers and to provide the most educational value at the same time.
Before continuing, be aware of the name of the working
platform, often referred to as the target triplet. A simple
way to determine the name of the target triplet is to run the
config.guess
script that comes with the source for many packages. Unpack
the Binutils sources and run the script: ./config.guess
and note the
output. For example, for a 32-bit Intel processor the output
will be i686-pc-linux-gnu. On a 64-bit
system it will be x86_64-pc-linux-gnu.
Also be aware of the name of the platform's dynamic linker,
often referred to as the dynamic loader (not to be confused
with the standard linker ld that is part of
Binutils). The dynamic linker provided by Glibc finds and
loads the shared libraries needed by a program, prepares the
program to run, and then runs it. The name of the dynamic
linker for a 32-bit Intel machine will be ld-linux.so.2
(ld-linux-x86-64.so.2
for 64-bit systems). A
sure-fire way to determine the name of the dynamic linker is
to inspect a random binary from the host system by running:
readelf -l <name of
binary> | grep interpreter
and noting the
output. The authoritative reference covering all platforms is
in the shlib-versions
file in
the root of the Glibc source tree.
Some key technical points of how the Chapter 5 build method works:
Slightly adjusting the name of the working platform, by
changing the "vendor" field target triplet by way of the
LFS_TGT
variable, ensures that
the first build of Binutils and GCC produces a compatible
cross-linker and cross-compiler. Instead of producing
binaries for another architecture, the cross-linker and
cross-compiler will produce binaries compatible with the
current hardware.
The temporary libraries are cross-compiled. Because a cross-compiler by its nature cannot rely on anything from its host system, this method removes potential contamination of the target system by lessening the chance of headers or libraries from the host being incorporated into the new tools. Cross-compilation also allows for the possibility of building both 32-bit and 64-bit libraries on 64-bit capable hardware.
Careful manipulation of the GCC source tells the compiler which target dynamic linker will be used.
Binutils is installed first because the configure runs of both GCC and Glibc perform various feature tests on the assembler and linker to determine which software features to enable or disable. This is more important than one might first realize. An incorrectly configured GCC or Glibc can result in a subtly broken toolchain, where the impact of such breakage might not show up until near the end of the build of an entire distribution. A test suite failure will usually highlight this error before too much additional work is performed.
Binutils installs its assembler and linker in two locations,
/tools/bin
and /tools/$LFS_TGT/bin
. The tools in one
location are hard linked to the other. An important facet of
the linker is its library search order. Detailed information
can be obtained from ld by passing it the
--verbose
flag. For
example, an ld --verbose | grep
SEARCH
will illustrate the current search paths
and their order. It shows which files are linked by
ld by compiling a
dummy program and passing the --verbose
switch to the linker.
For example, gcc dummy.c
-Wl,--verbose 2>&1 | grep succeeded
will
show all the files successfully opened during the linking.
The next package installed is GCC. An example of what can be seen during its run of configure is:
checking what assembler to use... /tools/i686-lfs-linux-gnu/bin/as
checking what linker to use... /tools/i686-lfs-linux-gnu/bin/ld
This is important for the reasons mentioned above. It also
demonstrates that GCC's configure script does not search the
PATH directories to find which tools to use. However, during
the actual operation of gcc itself, the same search
paths are not necessarily used. To find out which standard
linker gcc will
use, run: gcc
-print-prog-name=ld
.
Detailed information can be obtained from gcc by passing it the
-v
command line option
while compiling a dummy program. For example, gcc -v dummy.c
will show
detailed information about the preprocessor, compilation, and
assembly stages, including gcc's included search paths
and their order.
Next installed are sanitized Linux API headers. These allow the standard C library (Glibc) to interface with features that the Linux kernel will provide.
The next package installed is Glibc. The most important
considerations for building Glibc are the compiler, binary
tools, and kernel headers. The compiler is generally not an
issue since Glibc will always use the compiler relating to the
--host
parameter passed
to its configure script; e.g. in our case, the compiler will be
i686-lfs-linux-gnu-gcc. The
binary tools and kernel headers can be a bit more complicated.
Therefore, take no risks and use the available configure
switches to enforce the correct selections. After the run of
configure, check
the contents of the config.make
file in the glibc-build
directory
for all important details. Note the use of CC="i686-lfs-gnu-gcc"
to control
which binary tools are used and the use of the -nostdinc
and -isystem
flags to control the
compiler's include search path. These items highlight an
important aspect of the Glibc package—it is very
self-sufficient in terms of its build machinery and generally
does not rely on toolchain defaults.
During the second pass of Binutils, we are able to utilize the
--with-lib-path
configure switch to control ld's library search path.
For the second pass of GCC, its sources also need to be
modified to tell GCC to use the new dynamic linker. Failure to
do so will result in the GCC programs themselves having the
name of the dynamic linker from the host system's /lib
directory embedded into them, which
would defeat the goal of getting away from the host. From this
point onwards, the core toolchain is self-contained and
self-hosted. The remainder of the Chapter 5
packages all build against the new Glibc in /tools
.
Upon entering the chroot environment in Chapter 6,
the first major package to be installed is Glibc, due to its
self-sufficient nature mentioned above. Once this Glibc is
installed into /usr
, we will
perform a quick changeover of the toolchain defaults, and then
proceed in building the rest of the target LFS system.
When building packages there are several assumptions made within the instructions:
Several of the packages are patched before compilation, but only when the patch is needed to circumvent a problem. A patch is often needed in both this and the next chapter, but sometimes in only one or the other. Therefore, do not be concerned if instructions for a downloaded patch seem to be missing. Warning messages about offset or fuzz may also be encountered when applying a patch. Do not worry about these warnings, as the patch was still successfully applied.
During the compilation of most packages, there will be several warnings that scroll by on the screen. These are normal and can safely be ignored. These warnings are as they appear—warnings about deprecated, but not invalid, use of the C or C++ syntax. C standards change fairly often, and some packages still use the older standard. This is not a problem, but does prompt the warning.
Check one last time that the LFS
environment variable is set up
properly:
echo $LFS
Make sure the output shows the path to the LFS
partition's mount point, which is /mnt/lfs
, using our example.
Finally, two important items must be emphasized:
The build instructions assume that the Host System Requirements, including symbolic links, have been set properly:
bash is the shell in use.
sh is a symbolic link to bash.
/usr/bin/awk is a symbolic link to gawk.
/usr/bin/yacc is a symbolic link to bison or a small script that executes bison.
To re-emphasize the build process:
Place all the sources and patches in a directory
that will be accessible from the chroot
environment such as /mnt/lfs/sources/
. Do
not put
sources in /mnt/lfs/tools/
.
Change to the sources directory.
Using the tar program, extract the package to be built. In Chapter 5, ensure you are the lfs user when extracting the package.
Change to the directory created when the package was extracted.
Follow the book's instructions for building the package.
Change back to the sources directory.
Delete the extracted source directory unless instructed otherwise.
The Binutils package contains a linker, an assembler, and other tools for handling object files.
Go back and re-read the notes in the previous section. Understanding the notes labeled important will save you a lot of problems later.
It is important that Binutils be the first package compiled because both Glibc and GCC perform various tests on the available linker and assembler to determine which of their own features to enable.
The Binutils documentation recommends building Binutils in a dedicated build directory:
mkdir -v build cd build
In order for the SBU values listed in the rest of the book
to be of any use, measure the time it takes to build this
package from the configuration, up to and including the
first install. To achieve this easily, wrap the commands in
a time
command like this: time {
./configure ... && ... && make install;
}
.
The approximate build SBU values and required disk space in Chapter 5 does not include test suite data.
Now prepare Binutils for compilation:
../configure --prefix=/tools \ --with-sysroot=$LFS \ --with-lib-path=/tools/lib \ --target=$LFS_TGT \ --disable-nls \ --disable-werror
The meaning of the configure options:
--prefix=/tools
This tells the configure script to prepare to install
the Binutils programs in the /tools
directory.
--with-sysroot=$LFS
For cross compilation, this tells the build system to look in $LFS for the target system libraries as needed.
--with-lib-path=/tools/lib
This specifies which library path the linker should be configured to use.
--target=$LFS_TGT
Because the machine description in the LFS_TGT
variable is slightly different
than the value returned by the config.guess script,
this switch will tell the configure script to
adjust Binutil's build system for building a cross
linker.
--disable-nls
This disables internationalization as i18n is not needed for the temporary tools.
--disable-werror
This prevents the build from stopping in the event that there are warnings from the host's compiler.
Continue with compiling the package:
make
Compilation is now complete. Ordinarily we would now run the test suite, but at this early stage the test suite framework (Tcl, Expect, and DejaGNU) is not yet in place. The benefits of running the tests at this point are minimal since the programs from this first pass will soon be replaced by those from the second.
If building on x86_64, create a symlink to ensure the sanity of the toolchain:
case $(uname -m) in x86_64) mkdir -v /tools/lib && ln -sv lib /tools/lib64 ;; esac
Install the package:
make install
Details on this package are located in Section 6.16.2, “Contents of Binutils.”
The GCC package contains the GNU compiler collection, which includes the C and C++ compilers.
GCC now requires the GMP, MPFR and MPC packages. As these packages may not be included in your host distribution, they will be built with GCC. Unpack each package into the GCC source directory and rename the resulting directories so the GCC build procedures will automatically use them:
There are frequent misunderstandings about this chapter. The procedures are the same as every other chapter as explained earlier (Package build instructions). First extract the gcc tarball from the sources directory and then change to the directory created. Only then should you proceed with the instructions below.
tar -xf ../mpfr-4.0.1.tar.xz mv -v mpfr-4.0.1 mpfr tar -xf ../gmp-6.1.2.tar.xz mv -v gmp-6.1.2 gmp tar -xf ../mpc-1.1.0.tar.gz mv -v mpc-1.1.0 mpc
The following command will change the location of GCC's
default dynamic linker to use the one installed in
/tools
. It also removes
/usr/include
from GCC's include
search path. Issue:
for file in gcc/config/{linux,i386/linux{,64}}.h do cp -uv $file{,.orig} sed -e 's@/lib\(64\)\?\(32\)\?/ld@/tools&@g' \ -e 's@/usr@/tools@g' $file.orig > $file echo ' #undef STANDARD_STARTFILE_PREFIX_1 #undef STANDARD_STARTFILE_PREFIX_2 #define STANDARD_STARTFILE_PREFIX_1 "/tools/lib/" #define STANDARD_STARTFILE_PREFIX_2 ""' >> $file touch $file.orig done
In case the above seems hard to follow, let's break it down a
bit. First we copy the files gcc/config/linux.h
, gcc/config/i386/linux.h
, and gcc/config/i368/linux64.h
to a file of the
same name but with an added suffix of “.orig”. Then the first sed
expression prepends “/tools” to every instance of
“/lib/ld”, “/lib64/ld” or “/lib32/ld”, while the second one
replaces hard-coded instances of “/usr”.
Next, we add our define statements which alter the default
startfile prefix to the end of the file. Note that the
trailing “/” in “/tools/lib/” is required.
Finally, we use touch to update the
timestamp on the copied files. When used in conjunction with
cp -u, this
prevents unexpected changes to the original files in case the
commands are inadvertently run twice.
Finally, on x86_64 hosts, set the default directory name for 64-bit libraries to “lib”:
case $(uname -m) in x86_64) sed -e '/m64=/s/lib64/lib/' \ -i.orig gcc/config/i386/t-linux64 ;; esac
The GCC documentation recommends building GCC in a dedicated build directory:
mkdir -v build cd build
Prepare GCC for compilation:
../configure \ --target=$LFS_TGT \ --prefix=/tools \ --with-glibc-version=2.11 \ --with-sysroot=$LFS \ --with-newlib \ --without-headers \ --with-local-prefix=/tools \ --with-native-system-header-dir=/tools/include \ --disable-nls \ --disable-shared \ --disable-multilib \ --disable-decimal-float \ --disable-threads \ --disable-libatomic \ --disable-libgomp \ --disable-libmpx \ --disable-libquadmath \ --disable-libssp \ --disable-libvtv \ --disable-libstdcxx \ --enable-languages=c,c++
The meaning of the configure options:
--with-newlib
Since a working C library is not yet available, this ensures that the inhibit_libc constant is defined when building libgcc. This prevents the compiling of any code that requires libc support.
--without-headers
When creating a complete cross-compiler, GCC requires standard headers compatible with the target system. For our purposes these headers will not be needed. This switch prevents GCC from looking for them.
--with-local-prefix=/tools
The local prefix is the location in the system that GCC
will search for locally installed include files. The
default is /usr/local
.
Setting this to /tools
helps keep the host location of /usr/local
out of this GCC's search
path.
--with-native-system-header-dir=/tools/include
By default GCC searches /usr/include
for system headers. In
conjunction with the sysroot switch, this would
normally translate to $LFS/usr/include
. However the headers
that will be installed in the next two sections will go
to $LFS/tools/include
.
This switch ensures that gcc will find them correctly.
In the second pass of GCC, this same switch will ensure
that no headers from the host system are found.
--disable-shared
This switch forces GCC to link its internal libraries statically. We do this to avoid possible issues with the host system.
--disable-decimal-float,
--disable-threads, --disable-libatomic,
--disable-libgomp, --disable-libmpx,
--disable-libquadmath, --disable-libssp,
--disable-libvtv, --disable-libstdcxx
These switches disable support for the decimal floating point extension, threading, libatomic, libgomp, libmpx, libquadmath, libssp, libvtv, and the C++ standard library respectively. These features will fail to compile when building a cross-compiler and are not necessary for the task of cross-compiling the temporary libc.
--disable-multilib
On x86_64, LFS does not yet support a multilib configuration. This switch is harmless for x86.
--enable-languages=c,c++
This option ensures that only the C and C++ compilers are built. These are the only languages needed now.
Compile GCC by running:
make
Compilation is now complete. At this point, the test suite would normally be run, but, as mentioned before, the test suite framework is not in place yet. The benefits of running the tests at this point are minimal since the programs from this first pass will soon be replaced.
Install the package:
make install
Details on this package are located in Section 6.20.2, “Contents of GCC.”
The Linux API Headers (in linux-4.15.3.tar.xz) expose the kernel's API for use by Glibc.
The Linux kernel needs to expose an Application Programming Interface (API) for the system's C library (Glibc in LFS) to use. This is done by way of sanitizing various C header files that are shipped in the Linux kernel source tarball.
Make sure there are no stale files embedded in the package:
make mrproper
Now extract the user-visible kernel headers from the source. They are placed in an intermediate local directory and copied to the needed location because the extraction process removes any existing files in the target directory.
make INSTALL_HDR_PATH=dest headers_install cp -rv dest/include/* /tools/include
Details on this package are located in Section 6.7.2, “Contents of Linux API Headers.”
The Glibc package contains the main C library. This library provides the basic routines for allocating memory, searching directories, opening and closing files, reading and writing files, string handling, pattern matching, arithmetic, and so on.
The Glibc documentation recommends building Glibc in a dedicated build directory:
mkdir -v build cd build
Next, prepare Glibc for compilation:
../configure \ --prefix=/tools \ --host=$LFS_TGT \ --build=$(../scripts/config.guess) \ --enable-kernel=3.2 \ --with-headers=/tools/include \ libc_cv_forced_unwind=yes \ libc_cv_c_cleanup=yes
The meaning of the configure options:
--host=$LFS_TGT,
--build=$(../scripts/config.guess)
The combined effect of these switches is that Glibc's
build system configures itself to cross-compile, using
the cross-linker and cross-compiler in /tools
.
--enable-kernel=3.2
This tells Glibc to compile the library with support for 3.2 and later Linux kernels. Workarounds for older kernels are not enabled.
--with-headers=/tools/include
This tells Glibc to compile itself against the headers recently installed to the tools directory, so that it knows exactly what features the kernel has and can optimize itself accordingly.
libc_cv_forced_unwind=yes
The linker installed during Section 5.4, “Binutils-2.30 - Pass 1” was cross-compiled and as such cannot be used until Glibc has been installed. This means that the configure test for force-unwind support will fail, as it relies on a working linker. The libc_cv_forced_unwind=yes variable is passed in order to inform configure that force-unwind support is available without it having to run the test.
libc_cv_c_cleanup=yes
Similarly, we pass libc_cv_c_cleanup=yes through to the configure script so that the test is skipped and C cleanup handling support is configured.
During this stage the following warning might appear:
configure: WARNING: *** These auxiliary programs are missing or *** incompatible versions: msgfmt *** some features will be disabled. *** Check the INSTALL file for required versions.
The missing or incompatible msgfmt program is generally harmless. This msgfmt program is part of the Gettext package which the host distribution should provide.
There have been reports that this package may fail when building as a "parallel make". If this occurs, rerun the make command with a "-j1" option.
Compile the package:
make
Install the package:
make install
At this point, it is imperative to stop and ensure that the basic functions (compiling and linking) of the new toolchain are working as expected. To perform a sanity check, run the following commands:
echo 'int main(){}' > dummy.c $LFS_TGT-gcc dummy.c readelf -l a.out | grep ': /tools'
If everything is working correctly, there should be no errors, and the output of the last command will be of the form:
[Requesting program interpreter: /tools/lib64/ld-linux-x86-64.so.2]
Note that for 32-bit machines, the interpreter name will be
/tools/lib/ld-linux.so.2
.
If the output is not shown as above or there was no output at all, then something is wrong. Investigate and retrace the steps to find out where the problem is and correct it. This issue must be resolved before continuing on.
Once all is well, clean up the test files:
rm -v dummy.c a.out
Building Binutils in the section after next will serve as an additional check that the toolchain has been built properly. If Binutils fails to build, it is an indication that something has gone wrong with the previous Binutils, GCC, or Glibc installations.
Details on this package are located in Section 6.9.3, “Contents of Glibc.”
Libstdc++ is the standard C++ library. It is needed for the correct operation of the g++ compiler.
Libstdc++ is part of the
GCC sources. You should first unpack the GCC tarball and
change to the gcc-7.3.0
directory.
Create a separate build directory for Libstdc++ and enter it:
mkdir -v build cd build
Prepare Libstdc++ for compilation:
../libstdc++-v3/configure \ --host=$LFS_TGT \ --prefix=/tools \ --disable-multilib \ --disable-nls \ --disable-libstdcxx-threads \ --disable-libstdcxx-pch \ --with-gxx-include-dir=/tools/$LFS_TGT/include/c++/7.3.0
The meaning of the configure options:
--host=...
Indicates to use the cross compiler we have just built
instead of the one in /usr/bin
.
--disable-libstdcxx-threads
Since we have not yet built the C threads library, the C++ one cannot be built either.
--disable-libstdcxx-pch
This switch prevents the installation of precompiled include files, which are not needed at this stage.
--with-gxx-include-dir=/tools/$LFS_TGT/include/c++/7.3.0
This is the location where the standard include files are searched by the C++ compiler. In a normal build, this information is automatically passed to the Libstdc++ configure options from the top level directory. In our case, this information must be explicitly given.
Compile libstdc++ by running:
make
Install the library:
make install
Details on this package are located in Section 6.20.2, “Contents of GCC.”
The Binutils package contains a linker, an assembler, and other tools for handling object files.
Create a separate build directory again:
mkdir -v build cd build
Prepare Binutils for compilation:
CC=$LFS_TGT-gcc \ AR=$LFS_TGT-ar \ RANLIB=$LFS_TGT-ranlib \ ../configure \ --prefix=/tools \ --disable-nls \ --disable-werror \ --with-lib-path=/tools/lib \ --with-sysroot
The meaning of the new configure options:
CC=$LFS_TGT-gcc AR=$LFS_TGT-ar
RANLIB=$LFS_TGT-ranlib
Because this is really a native build of Binutils, setting these variables ensures that the build system uses the cross-compiler and associated tools instead of the ones on the host system.
--with-lib-path=/tools/lib
This tells the configure script to specify the library
search path during the compilation of Binutils,
resulting in /tools/lib
being passed to the linker. This prevents the linker
from searching through library directories on the host.
--with-sysroot
The sysroot feature enables the linker to find shared objects which are required by other shared objects explicitly included on the linker's command line. Without this, some packages may not build successfully on some hosts.
Compile the package:
make
Install the package:
make install
Now prepare the linker for the “Re-adjusting” phase in the next chapter:
make -C ld clean make -C ld LIB_PATH=/usr/lib:/lib cp -v ld/ld-new /tools/bin
The meaning of the make parameters:
-C ld
clean
This tells the make program to remove all compiled
files in the ld
subdirectory.
-C ld
LIB_PATH=/usr/lib:/lib
This option rebuilds everything in the ld
subdirectory. Specifying the
LIB_PATH
Makefile variable
on the command line allows us to override the default
value of the temporary tools and point it to the proper
final path. The value of this variable specifies the
linker's default library search path. This preparation
is used in the next chapter.
Details on this package are located in Section 6.16.2, “Contents of Binutils.”
The GCC package contains the GNU compiler collection, which includes the C and C++ compilers.
Our first build of GCC has installed a couple of internal
system headers. Normally one of them, limits.h
, will in turn include the
corresponding system limits.h
header, in this case, /tools/include/limits.h
. However, at the
time of the first build of gcc /tools/include/limits.h
did not exist, so
the internal header that GCC installed is a partial,
self-contained file and does not include the extended
features of the system header. This was adequate for building
the temporary libc, but this build of GCC now requires the
full internal header. Create a full version of the internal
header using a command that is identical to what the GCC
build system does in normal circumstances:
cat gcc/limitx.h gcc/glimits.h gcc/limity.h > \ `dirname $($LFS_TGT-gcc -print-libgcc-file-name)`/include-fixed/limits.h
Once again, change the location of GCC's default dynamic
linker to use the one installed in /tools
.
for file in gcc/config/{linux,i386/linux{,64}}.h do cp -uv $file{,.orig} sed -e 's@/lib\(64\)\?\(32\)\?/ld@/tools&@g' \ -e 's@/usr@/tools@g' $file.orig > $file echo ' #undef STANDARD_STARTFILE_PREFIX_1 #undef STANDARD_STARTFILE_PREFIX_2 #define STANDARD_STARTFILE_PREFIX_1 "/tools/lib/" #define STANDARD_STARTFILE_PREFIX_2 ""' >> $file touch $file.orig done
If building on x86_64, change the default directory name for 64-bit libraries to “lib”:
case $(uname -m) in x86_64) sed -e '/m64=/s/lib64/lib/' \ -i.orig gcc/config/i386/t-linux64 ;; esac
As in the first build of GCC it requires the GMP, MPFR and MPC packages. Unpack the tarballs and move them into the required directory names:
tar -xf ../mpfr-4.0.1.tar.xz mv -v mpfr-4.0.1 mpfr tar -xf ../gmp-6.1.2.tar.xz mv -v gmp-6.1.2 gmp tar -xf ../mpc-1.1.0.tar.gz mv -v mpc-1.1.0 mpc
Create a separate build directory again:
mkdir -v build cd build
Before starting to build GCC, remember to unset any environment variables that override the default optimization flags.
Now prepare GCC for compilation:
CC=$LFS_TGT-gcc \ CXX=$LFS_TGT-g++ \ AR=$LFS_TGT-ar \ RANLIB=$LFS_TGT-ranlib \ ../configure \ --prefix=/tools \ --with-local-prefix=/tools \ --with-native-system-header-dir=/tools/include \ --enable-languages=c,c++ \ --disable-libstdcxx-pch \ --disable-multilib \ --disable-bootstrap \ --disable-libgomp
The meaning of the new configure options:
--enable-languages=c,c++
This option ensures that both the C and C++ compilers are built.
--disable-libstdcxx-pch
Do not build the pre-compiled header (PCH) for
libstdc++
. It takes up a
lot of space, and we have no use for it.
--disable-bootstrap
For native builds of GCC, the default is to do a "bootstrap" build. This does not just compile GCC, but compiles it several times. It uses the programs compiled in a first round to compile itself a second time, and then again a third time. The second and third iterations are compared to make sure it can reproduce itself flawlessly. This also implies that it was compiled correctly. However, the LFS build method should provide a solid compiler without the need to bootstrap each time.
Compile the package:
make
Install the package:
make install
As a finishing touch, create a symlink. Many programs and scripts run cc instead of gcc, which is used to keep programs generic and therefore usable on all kinds of UNIX systems where the GNU C compiler is not always installed. Running cc leaves the system administrator free to decide which C compiler to install:
ln -sv gcc /tools/bin/cc
At this point, it is imperative to stop and ensure that the basic functions (compiling and linking) of the new toolchain are working as expected. To perform a sanity check, run the following commands:
echo 'int main(){}' > dummy.c cc dummy.c readelf -l a.out | grep ': /tools'
If everything is working correctly, there should be no errors, and the output of the last command will be of the form:
[Requesting program interpreter: /tools/lib64/ld-linux.so.2]
Note that /tools/lib
wiil be
the prefix of the dynamic linker for 32-bit machines.
If the output is not shown as above or there was no output
at all, then something is wrong. Investigate and retrace
the steps to find out where the problem is and correct it.
This issue must be resolved before continuing on. First,
perform the sanity check again, using gcc instead of
cc. If this
works, then the /tools/bin/cc
symlink is missing. Install the symlink as per above. Next,
ensure that the PATH
is correct.
This can be checked by running echo $PATH and verifying
that /tools/bin
is at the
head of the list. If the PATH
is
wrong it could mean that you are not logged in as user
lfs
or that something went
wrong back in Section 4.4,
“Setting Up the Environment.”
Once all is well, clean up the test files:
rm -v dummy.c a.out
Details on this package are located in Section 6.20.2, “Contents of GCC.”
The Tcl package contains the Tool Command Language.
This package and the next two (Expect and DejaGNU) are installed to support running the test suites for GCC and Binutils and other packages. Installing three packages for testing purposes may seem excessive, but it is very reassuring, if not essential, to know that the most important tools are working properly. Even if the test suites are not run in this chapter (they are not mandatory), these packages are required to run the test suites in Chapter 6.
Note that the Tcl package used here is a minimal version needed to run the LFS tests. For the full package, see the BLFS Tcl procedures.
Prepare Tcl for compilation:
cd unix ./configure --prefix=/tools
Build the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Tcl test suite anyway, issue the following command:
TZ=UTC make test
The Tcl test suite may experience failures under certain host
conditions that are not fully understood. Therefore, test
suite failures here are not surprising, and are not
considered critical. The TZ=UTC
parameter sets the time
zone to Coordinated Universal Time (UTC), but only for the
duration of the test suite run. This ensures that the clock
tests are exercised correctly. Details on the TZ
environment variable are provided in
Chapter 7.
Install the package:
make install
Make the installed library writable so debugging symbols can be removed later:
chmod -v u+w /tools/lib/libtcl8.6.so
Install Tcl's headers. The next package, Expect, requires them to build.
make install-private-headers
Now make a necessary symbolic link:
ln -sv tclsh8.6 /tools/bin/tclsh
The Expect package contains a program for carrying out scripted dialogues with other interactive programs.
First, force Expect's configure script to use /bin/stty
instead of a /usr/local/bin/stty
it may find on the host
system. This will ensure that our test suite tools remain
sane for the final builds of our toolchain:
cp -v configure{,.orig} sed 's:/usr/local/bin:/bin:' configure.orig > configure
Now prepare Expect for compilation:
./configure --prefix=/tools \ --with-tcl=/tools/lib \ --with-tclinclude=/tools/include
The meaning of the configure options:
--with-tcl=/tools/lib
This ensures that the configure script finds the Tcl installation in the temporary tools location instead of possibly locating an existing one on the host system.
--with-tclinclude=/tools/include
This explicitly tells Expect where to find Tcl's internal headers. Using this option avoids conditions where configure fails because it cannot automatically discover the location of Tcl's headers.
Build the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Expect test suite anyway, issue the following command:
make test
Note that the Expect test suite is known to experience failures under certain host conditions that are not within our control. Therefore, test suite failures here are not surprising and are not considered critical.
Install the package:
make SCRIPTS="" install
The meaning of the make parameter:
SCRIPTS=""
This prevents installation of the supplementary Expect scripts, which are not needed.
The DejaGNU package contains a framework for testing other programs.
Prepare DejaGNU for compilation:
./configure --prefix=/tools
Build and install the package:
make install
To test the results, issue:
make check
The M4 package contains a macro processor.
Prepare M4 for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the M4 test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.14.2, “Contents of M4.”
The Ncurses package contains libraries for terminal-independent handling of character screens.
First, ensure that gawk is found first during configuration:
sed -i s/mawk// configure
Prepare Ncurses for compilation:
./configure --prefix=/tools \ --with-shared \ --without-debug \ --without-ada \ --enable-widec \ --enable-overwrite
The meaning of the configure options:
--without-ada
This ensures that Ncurses does not build support for the Ada compiler which may be present on the host but will not be available once we enter the chroot environment.
--enable-overwrite
This tells Ncurses to install its header files into
/tools/include
, instead
of /tools/include/ncurses
, to ensure
that other packages can find the Ncurses headers
successfully.
--enable-widec
This switch causes wide-character libraries (e.g.,
libncursesw.so.6.1
) to be
built instead of normal ones (e.g., libncurses.so.6.1
). These
wide-character libraries are usable in both multibyte
and traditional 8-bit locales, while normal libraries
work properly only in 8-bit locales. Wide-character and
normal libraries are source-compatible, but not
binary-compatible.
Compile the package:
make
This package has a test suite, but it can only be run after
the package has been installed. The tests reside in the
test/
directory. See the
README
file in that directory
for further details.
Install the package:
make install
Details on this package are located in Section 6.23.2, “Contents of Ncurses.”
The Bash package contains the Bourne-Again SHell.
Prepare Bash for compilation:
./configure --prefix=/tools --without-bash-malloc
The meaning of the configure options:
--without-bash-malloc
This option turns off the use of Bash's memory
allocation (malloc
)
function which is known to cause segmentation faults.
By turning this option off, Bash will use the
malloc
functions from
Glibc which are more stable.
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Bash test suite anyway, issue the following command:
make tests
Install the package:
make install
Make a link for the programs that use sh for a shell:
ln -sv bash /tools/bin/sh
Details on this package are located in Section 6.34.2, “Contents of Bash.”
The Bison package contains a parser generator.
Prepare Bison for compilation:
./configure --prefix=/tools
Compile the package:
make
To test the results, issue:
make check
Install the package:
make install
Details on this package are located in Section 6.31.2, “Contents of Bison.”
The Bzip2 package contains programs for compressing and decompressing files. Compressing text files with bzip2 yields a much better compression percentage than with the traditional gzip.
The Bzip2 package does not contain a configure script. Compile and test it with:
make
Install the package:
make PREFIX=/tools install
Details on this package are located in Section 6.21.2, “Contents of Bzip2.”
The Coreutils package contains utilities for showing and setting the basic system characteristics.
Prepare Coreutils for compilation:
./configure --prefix=/tools --enable-install-program=hostname
The meaning of the configure options:
--enable-install-program=hostname
This enables the hostname binary to be built and installed – it is disabled by default but is required by the Perl test suite.
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Coreutils test suite anyway, issue the following command:
make RUN_EXPENSIVE_TESTS=yes check
The RUN_EXPENSIVE_TESTS=yes
parameter tells the test suite to run several additional
tests that are considered relatively expensive (in terms of
CPU power and memory usage) on some platforms, but generally
are not a problem on Linux.
Install the package:
make install
Details on this package are located in Section 6.56.2, “Contents of Coreutils.”
The Diffutils package contains programs that show the differences between files or directories.
Prepare Diffutils for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Diffutils test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.58.2, “Contents of Diffutils.”
The File package contains a utility for determining the type of a given file or files.
Prepare File for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the File test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.12.2, “Contents of File.”
The Findutils package contains programs to find files. These programs are provided to recursively search through a directory tree and to create, maintain, and search a database (often faster than the recursive find, but unreliable if the database has not been recently updated).
Prepare Findutils for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Findutils test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.60.2, “Contents of Findutils.”
The Gawk package contains programs for manipulating text files.
Prepare Gawk for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Gawk test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.59.2, “Contents of Gawk.”
The Gettext package contains utilities for internationalization and localization. These allow programs to be compiled with NLS (Native Language Support), enabling them to output messages in the user's native language.
For our temporary set of tools, we only need to build and install three programs from Gettext.
Prepare Gettext for compilation:
cd gettext-tools EMACS="no" ./configure --prefix=/tools --disable-shared
The meaning of the configure option:
EMACS="no"
This prevents the configure script from determining where to install Emacs Lisp files as the test is known to hang on some hosts.
--disable-shared
We do not need to install any of the shared Gettext libraries at this time, therefore there is no need to build them.
Compile the package:
make -C gnulib-lib make -C intl pluralx.c make -C src msgfmt make -C src msgmerge make -C src xgettext
As only three programs have been compiled, it is not possible to run the test suite without compiling additional support libraries from the Gettext package. It is therefore not recommended to attempt to run the test suite at this stage.
Install the msgfmt, msgmerge and xgettext programs:
cp -v src/{msgfmt,msgmerge,xgettext} /tools/bin
Details on this package are located in Section 6.47.2, “Contents of Gettext.”
The Grep package contains programs for searching through files.
Prepare Grep for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Grep test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.33.2, “Contents of Grep.”
The Gzip package contains programs for compressing and decompressing files.
Prepare Gzip for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Gzip test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.64.2, “Contents of Gzip.”
The Make package contains a program for compiling packages.
First, work around an error caused by glibc-2.27:
sed -i '211,217 d; 219,229 d; 232 d' glob/glob.c
Prepare Make for compilation:
./configure --prefix=/tools --without-guile
The meaning of the configure option:
--without-guile
This ensures that Make-4.2.1 won't link against Guile libraries, which may be present on the host system, but won't be available within the chroot environment in the next chapter.
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Make test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.68.2, “Contents of Make.”
The Patch package contains a program for modifying or creating files by applying a “patch” file typically created by the diff program.
Prepare Patch for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Patch test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.69.2, “Contents of Patch.”
The Perl package contains the Practical Extraction and Report Language.
Prepare Perl for compilation:
sh Configure -des -Dprefix=/tools -Dlibs=-lm
Build the package:
make
Although Perl comes with a test suite, it would be better to wait until it is installed in the next chapter.
Only a few of the utilities and libraries need to be installed at this time:
cp -v perl cpan/podlators/scripts/pod2man /tools/bin mkdir -pv /tools/lib/perl5/5.26.1 cp -Rv lib/* /tools/lib/perl5/5.26.1
Details on this package are located in Section 6.40.2, “Contents of Perl.”
The Sed package contains a stream editor.
Prepare Sed for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Sed test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.27.2, “Contents of Sed.”
The Tar package contains an archiving program.
Prepare Tar for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Tar test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.75.2, “Contents of Tar.”
The Texinfo package contains programs for reading, writing, and converting info pages.
Prepare Texinfo for compilation:
./configure --prefix=/tools
As part of the configure process, a test is made that indicates an error for TestXS_la-TestXS.lo. This is not relevant for LFS and should be ignored.
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Texinfo test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.76.2, “Contents of Texinfo.”
The Util-linux package contains miscellaneous utility programs.
Prepare Util-linux for compilation:
./configure --prefix=/tools \ --without-python \ --disable-makeinstall-chown \ --without-systemdsystemunitdir \ --without-ncurses \ PKG_CONFIG=""
The meaning of the configure option:
--without-python
This switch disables using Python if it is installed on the host system. It avoids trying to build unneeded bindings.
--disable-makeinstall-chown
This switch disables using the chown command during installation. This is not needed when installing into the /tools directory and avoids the necessity of installing as root.
--without-ncurses
This switch disables using the ncurses library for the build process. This is not needed when installing into the /tools directory and avoids problems on some host distros.
--without-systemdsystemunitdir
On systems that use systemd, the package tries to install a systemd specific file to a non-existent directory in /tools. This switch disables the unnecessary action.
PKG_CONFIG=""
Setting this environment variable prevents adding unneeded features that may be available on the host. Note that the location shown for setting this environment variable is different from other LFS sections where variables are set preceding the command. This location is shown to demonstrate an alternative way of setting an environment variable when using configure.
Compile the package:
make
Install the package:
make install
The Xz package contains programs for compressing and decompressing files. It provides capabilities for the lzma and the newer xz compression formats. Compressing text files with xz yields a better compression percentage than with the traditional gzip or bzip2 commands.
Prepare Xz for compilation:
./configure --prefix=/tools
Compile the package:
make
Compilation is now complete. As discussed earlier, running the test suite is not mandatory for the temporary tools here in this chapter. To run the Xz test suite anyway, issue the following command:
make check
Install the package:
make install
Details on this package are located in Section 6.45.2, “Contents of Xz.”
The steps in this section are optional, but if the LFS partition is rather small, it is beneficial to learn that unnecessary items can be removed. The executables and libraries built so far contain about 70 MB of unneeded debugging symbols. Remove those symbols with:
strip --strip-debug /tools/lib/* /usr/bin/strip --strip-unneeded /tools/{,s}bin/*
These commands will skip a number of files, reporting that it does not recognize their file format. Most of these are scripts instead of binaries. Also use the system strip command to include the strip binary in /tools.
Take care not to use
--strip-unneeded
on the
libraries. The static ones would be destroyed and the toolchain
packages would need to be built all over again.
To save more, remove the documentation:
rm -rf /tools/{,share}/{info,man,doc}
Remove unneeded files:
find /tools/{lib,libexec} -name \*.la -delete
At this point, you should have at least 3 GB of free space in
$LFS
that can be used to build and
install Glibc and Gcc in the next phase. If you can build and
install Glibc, you can build and install the rest too.
The commands in the remainder of this book must be performed
while logged in as user root
and no longer as user lfs
.
Also, double check that $LFS
is
set in root
's environment.
Currently, the $LFS/tools
directory is owned by the user lfs
, a user that exists only on the host
system. If the $LFS/tools
directory is kept as is, the files are owned by a user ID
without a corresponding account. This is dangerous because a
user account created later could get this same user ID and
would own the $LFS/tools
directory and all the files therein, thus exposing these files
to possible malicious manipulation.
To avoid this issue, you could add the lfs
user to the new LFS system later when
creating the /etc/passwd
file,
taking care to assign it the same user and group IDs as on the
host system. Better yet, change the ownership of the
$LFS/tools
directory to user
root
by running the following
command:
chown -R root:root $LFS/tools
Although the $LFS/tools
directory
can be deleted once the LFS system has been finished, it can be
retained to build additional LFS systems of the same book version. How best
to backup $LFS/tools
is a matter
of personal preference.
If you intend to keep the temporary tools for use in building future LFS systems, now is the time to back them up. Subsequent commands in chapter 6 will alter the tools currently in place, rendering them useless for future builds.
In this chapter, we enter the building site and start constructing the LFS system in earnest. That is, we chroot into the temporary mini Linux system, make a few final preparations, and then begin installing the packages.
The installation of this software is straightforward. Although in many cases the installation instructions could be made shorter and more generic, we have opted to provide the full instructions for every package to minimize the possibilities for mistakes. The key to learning what makes a Linux system work is to know what each package is used for and why you (or the system) may need it.
We do not recommend using optimizations. They can make a
program run slightly faster, but they may also cause
compilation difficulties and problems when running the program.
If a package refuses to compile when using optimization, try to
compile it without optimization and see if that fixes the
problem. Even if the package does compile when using
optimization, there is the risk it may have been compiled
incorrectly because of the complex interactions between the
code and build tools. Also note that the -march
and -mtune
options using values not specified in the book have not been
tested. This may cause problems with the toolchain packages
(Binutils, GCC and Glibc). The small potential gains achieved
in using compiler optimizations are often outweighed by the
risks. First-time builders of LFS are encouraged to build
without custom optimizations. The subsequent system will still
run very fast and be stable at the same time.
The order that packages are installed in this chapter needs to
be strictly followed to ensure that no program accidentally
acquires a path referring to /tools
hard-wired into it. For the same
reason, do not compile separate packages in parallel. Compiling
in parallel may save time (especially on dual-CPU machines),
but it could result in a program containing a hard-wired path
to /tools
, which will cause the
program to stop working when that directory is removed.
Before the installation instructions, each installation page provides information about the package, including a concise description of what it contains, approximately how long it will take to build, and how much disk space is required during this building process. Following the installation instructions, there is a list of programs and libraries (along with brief descriptions of these) that the package installs.
The SBU values and required disk space includes test suite data for all applicable packages in Chapter 6.
In general, the LFS editors discourage building and installing static libraries. The original purpose for most static libraries has been made obsolete in a modern Linux system. In addition linking a static library into a program can be detrimental. If an update to the library is needed to remove a security problem, all programs that use the static library will need to be relinked to the new library. Since the use of static libraries is not always obvious, the relevant programs (and the procedures needed to do the linking) may not even be known.
In the procedures in Chapter 6, we remove or disable
installation of most static libraries. Usually this is done
by passing a --disable-static
option to configure. In other cases,
alternate means are needed. In a few cases, especially glibc
and gcc, the use of static libraries remains essential to the
general package building process.
For a more complete discussion of libraries, see the discussion Libraries: Static or shared? in the BLFS book.
Various file systems exported by the kernel are used to communicate to and from the kernel itself. These file systems are virtual in that no disk space is used for them. The content of the file systems resides in memory.
Begin by creating directories onto which the file systems will be mounted:
mkdir -pv $LFS/{dev,proc,sys,run}
When the kernel boots the system, it requires the presence of
a few device nodes, in particular the console
and null
devices. The device nodes must be
created on the hard disk so that they are available before
udevd has been
started, and additionally when Linux is started with
init=/bin/bash
.
Create the devices by running the following commands:
mknod -m 600 $LFS/dev/console c 5 1 mknod -m 666 $LFS/dev/null c 1 3
The recommended method of populating the /dev
directory with devices is to mount a
virtual filesystem (such as tmpfs
) on the /dev
directory, and allow the devices to be
created dynamically on that virtual filesystem as they are
detected or accessed. Device creation is generally done
during the boot process by Udev. Since this new system does
not yet have Udev and has not yet been booted, it is
necessary to mount and populate /dev
manually. This is accomplished by bind
mounting the host system's /dev
directory. A bind mount is a special type of mount that
allows you to create a mirror of a directory or mount point
to some other location. Use the following command to achieve
this:
mount -v --bind /dev $LFS/dev
Now mount the remaining virtual kernel filesystems:
mount -vt devpts devpts $LFS/dev/pts -o gid=5,mode=620 mount -vt proc proc $LFS/proc mount -vt sysfs sysfs $LFS/sys mount -vt tmpfs tmpfs $LFS/run
The meaning of the mount options for devpts:
gid=5
This ensures that all devpts-created device nodes are
owned by group ID 5. This is the ID we will use later
on for the tty
group.
We use the group ID instead of a name, since the host
system might use a different ID for its tty
group.
mode=0620
This ensures that all devpts-created device nodes have mode 0620 (user readable and writable, group writable). Together with the option above, this ensures that devpts will create device nodes that meet the requirements of grantpt(), meaning the Glibc pt_chown helper binary (which is not installed by default) is not necessary.
In some host systems, /dev/shm
is a symbolic link to /run/shm
.
The /run tmpfs was mounted above so in this case only a
directory needs to be created.
if [ -h $LFS/dev/shm ]; then mkdir -pv $LFS/$(readlink $LFS/dev/shm) fi
Package Management is an often requested addition to the LFS Book. A Package Manager allows tracking the installation of files making it easy to remove and upgrade packages. As well as the binary and library files, a package manager will handle the installation of configuration files. Before you begin to wonder, NO—this section will not talk about nor recommend any particular package manager. What it provides is a roundup of the more popular techniques and how they work. The perfect package manager for you may be among these techniques or may be a combination of two or more of these techniques. This section briefly mentions issues that may arise when upgrading packages.
Some reasons why no package manager is mentioned in LFS or BLFS include:
Dealing with package management takes the focus away from the goals of these books—teaching how a Linux system is built.
There are multiple solutions for package management, each having its strengths and drawbacks. Including one that satisfies all audiences is difficult.
There are some hints written on the topic of package management. Visit the Hints Project and see if one of them fits your need.
A Package Manager makes it easy to upgrade to newer versions when they are released. Generally the instructions in the LFS and BLFS Book can be used to upgrade to the newer versions. Here are some points that you should be aware of when upgrading packages, especially on a running system.
If Glibc needs to be upgraded to a newer version, (e.g. from glibc-2.19 to glibc-2.20, it is safer to rebuild LFS. Though you may be able to rebuild all the packages in their dependency order, we do not recommend it.
If a package containing a shared library is updated,
and if the name of the library changes, then all the
packages dynamically linked to the library need to be
recompiled to link against the newer library. (Note
that there is no correlation between the package
version and the name of the library.) For example,
consider a package foo-1.2.3 that installs a shared
library with name libfoo.so.1
. Say you upgrade the
package to a newer version foo-1.2.4 that installs a
shared library with name libfoo.so.2
. In this case, all
packages that are dynamically linked to libfoo.so.1
need to be recompiled to
link against libfoo.so.2
.
Note that you should not remove the previous libraries
until the dependent packages are recompiled.
The following are some common package management techniques. Before making a decision on a package manager, do some research on the various techniques, particularly the drawbacks of the particular scheme.
Yes, this is a package management technique. Some folks do not find the need for a package manager because they know the packages intimately and know what files are installed by each package. Some users also do not need any package management because they plan on rebuilding the entire system when a package is changed.
This is a simplistic package management that does not need
any extra package to manage the installations. Each package
is installed in a separate directory. For example, package
foo-1.1 is installed in /usr/pkg/foo-1.1
and a symlink is made
from /usr/pkg/foo
to
/usr/pkg/foo-1.1
. When
installing a new version foo-1.2, it is installed in
/usr/pkg/foo-1.2
and the
previous symlink is replaced by a symlink to the new
version.
Environment variables such as PATH
, LD_LIBRARY_PATH
, MANPATH
, INFOPATH
and CPPFLAGS