Ignore:
Timestamp:
06/16/2020 11:56:28 AM (4 years ago)
Author:
Bruce Dubbs <bdubbs@…>
Branches:
10.0, 10.0-rc1, 10.1, 10.1-rc1, 11.0, 11.0-rc1, 11.0-rc2, 11.0-rc3, 11.1, 11.1-rc1, 11.2, 11.2-rc1, 11.3, 11.3-rc1, 12.0, 12.0-rc1, 12.1, 12.1-rc1, arm, bdubbs/gcc13, ml-11.0, multilib, renodr/libudev-from-systemd, s6-init, trunk, xry111/arm64, xry111/arm64-12.0, xry111/clfs-ng, xry111/lfs-next, xry111/loongarch, xry111/loongarch-12.0, xry111/loongarch-12.1, xry111/mips64el, xry111/pip3, xry111/rust-wip-20221008, xry111/update-glibc
Children:
9a05e45
Parents:
560065f (diff), 1cd5961 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.
Message:

Split Chapter 5 into three separate chapters.
Implement a new method of cross-building the LFS tool chain
and other tools to simplify the method of isolating the
new system from the original host. This will be the start of
LFS-10.0.

Move old trunk/BOOK to branches/old-trunk.

git-svn-id: ​http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11946 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

File:
1 edited

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  • chapter06/introduction.xml

    r560065f r675606b  
    66]>
    77
    8 <sect1 id="ch-system-introduction">
     8<sect1 id="ch-tools-introduction-cross">
    99  <?dbhtml filename="introduction.html"?>
    1010
    1111  <title>Introduction</title>
    1212
    13   <para>In this chapter, we enter the building site and start constructing the
    14   LFS system in earnest. That is, we chroot into the temporary mini Linux system,
    15   make a few final preparations, and then begin installing the packages.</para>
     13  <para>This chapter shows how to cross-compile basic utilities using
     14  the just built cross-toolchain. Those utilities are installed into
     15  their final location, but cannot be used yet. Basic tasks still rely on
     16  the host's tools. Nevertheless, the installed libraries are used when
     17  linking.</para>
    1618
    17   <para>The installation of this software is straightforward. Although in many
    18   cases the installation instructions could be made shorter and more generic,
    19   we have opted to provide the full instructions for every package to minimize
    20   the possibilities for mistakes.  The key to learning what makes a Linux system
    21   work is to know what each package is used for and why you (or the system)
    22   may need it.</para>
     19  <para>Using the utilities will be possible in next chapter after entering
     20  the <quote>chroot</quote> environment. But all the packages built in the
     21  present chapter need to be built before we do that. Therefore we cannot be
     22  independent of the host system yet.</para>
    2323
    24   <para>We do not recommend using optimizations.  They can make
    25   a program run slightly faster, but they may also cause compilation
    26   difficulties and problems when running the program.  If a package refuses to
    27   compile when using optimization, try to compile it without optimization and
    28   see if that fixes the problem. Even if the package does compile when using
    29   optimization, there is the risk it may have been compiled incorrectly because
    30   of the complex interactions between the code and build tools.  Also note that
    31   the <option>-march</option> and <option>-mtune</option> options using values
    32   not specified in the book have not been tested. This may cause problems with
    33   the toolchain packages (Binutils, GCC and Glibc).  The small potential gains
    34   achieved in using compiler optimizations are often outweighed by the risks.
    35   First-time builders of LFS are encouraged to build without custom
    36   optimizations. The subsequent system will still run very fast and be stable
    37   at the same time.</para>
    38 
    39   <para>The order that packages are installed in this chapter needs to be
    40   strictly followed to ensure that no program accidentally acquires a path
    41   referring to <filename class="directory">/tools</filename> hard-wired into
    42   it.  For the same reason, do not compile separate packages in parallel.
    43   Compiling in parallel may save time (especially on dual-CPU machines), but it
    44   could result in a program containing a hard-wired path to <filename
    45   class="directory">/tools</filename>, which will cause the program to stop
    46   working when that directory is removed.</para>
    47 
    48   <para>Before the installation instructions, each installation page provides
    49   information about the package, including a concise description of what it
    50   contains, approximately how long it will take to build, and how much disk
    51   space is required during this building process. Following the installation
    52   instructions, there is a list of programs and libraries (along with brief
    53   descriptions of these) that the package installs.</para>
    54 
    55   <note><para>The SBU values and required disk space includes
    56   test suite data for all applicable packages in Chapter&nbsp;6.</para></note>
    57 
    58   <sect2>
    59     <title>About libraries</title>
    60 
    61     <para>In general, the LFS editors discourage building and installing static
    62     libraries.  The original purpose for most static libraries has been made
    63     obsolete in a modern Linux system.  In addition linking a static library
    64     into a program can be detrimental.  If an update to the library is needed
    65     to remove a security problem, all programs that use the static library will
    66     need to be relinked to the new library.  Since the use of static libraries
    67     is not always obvious, the relevant programs (and the procedures needed to
    68     do the linking) may not even be known.</para>
    69 
    70     <para>In the procedures in Chapter&nbsp;6, we remove or disable installation of
    71     most static libraries. Usually this is done by passing a
    72     <option>--disable-static</option> option to <command>configure</command>.
    73     In other cases, alternate means are needed. In a few cases, especially
    74     glibc and gcc, the use of static libraries remains essential to the general
    75     package building process. </para>
    76 
    77     <para>For a more complete discussion of libraries, see the discussion
    78     <ulink url="&blfs-root;/view/&short-version;/introduction/libraries.html">
    79     Libraries: Static or shared?</ulink> in the BLFS book.</para>
    80 
    81   </sect2>
     24  <para>Once again, let us recall that improper setting of <envar>LFS</envar>
     25  together with building as root, may render your computer unusable.
     26  This whole chapter must be done as user <systemitem
     27  class="username">lfs</systemitem>, with the enviroment as described in
     28  <xref linkend="ch-preps-settingenviron"/>.</para>
    8229
    8330</sect1>
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