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Restructure ch7-stripping

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git-svn-id: http://svn.linuxfromscratch.org/LFS/branches/cross2@11920 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689
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Thomas Trepl 2020-06-11 12:14:42 +00:00
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chapter07/stripping.xml
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@ -16,22 +16,70 @@
a backup of the temporary tools.
</para>
<para>
The following steps are performed from outside the chroot
environment. That means, you have to leave the chroot environment
first before continuing. The reason for that is to
<itemizedlist>
<listitem>
<para>
make sure that objects are not in use while they gets
manipulated.
</para>
</listitem>
<listitem>
<para>
get access to file system locations outside of the chroot
environment to store/read the backup archive which should
not be placed within the
<filename class="directory">$LFS</filename> hierarchy for
safety reasons.
</para>
</listitem>
</itemizedlist>
</para>
<para>
Leave the chroot environment and unmount the kernel virtual file
systems:
</para>
<screen role="nodump"><userinput>exit
umount $LFS/dev{/pts,}
umount $LFS/{sys,proc,run}</userinput></screen>
<note>
<para>All of the following instructions are executed by
<systemitem class="username">root</systemitem>. Take extra
care about the commands you're going to run as mistakes
here can modify your host system. Be aware that the
environment variable <envar>LFS</envar> is set for user
<systemitem class="username">lfs</systemitem> by default
but it might <emphasis>not</emphasis> be set for
<systemitem class="username">root</systemitem>. Whenever
commands are to be executed by <systemitem class="username">root</systemitem>,
make sure you have set <envar>LFS</envar> accordingly.
This has been discussed in <xref linkend='ch-partitioning-aboutlfs'/>.
</para>
</note>
<sect2>
<title>Stripping</title>
<para>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.</para>
learn that unnecessary items can be removed. The executables and
libraries built so far contain about 94 MB of unneeded debugging
symbols.</para>
<screen><userinput>strip --strip-debug /usr/lib/*
strip --strip-unneeded /usr/{,s}bin/*
strip --strip-unneeded /tools/bin/*</userinput></screen>
<para>Strip off debugging symbols from binaries:</para>
<screen role="nodump"><userinput>strip --strip-debug $LFS/usr/lib/*
strip --strip-unneeded $LFS/usr/{,s}bin/*
strip --strip-unneeded $LFS/tools/bin/*</userinput></screen>
<para>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.
<!--Note that we use the <command>strip</command> program built in
<quote>Binutils pass 1</quote>, since it is the one that knows how to strip
<quote>Binutils pass 2</quote>, since it is the one that knows how to strip
our cross-compiled programs.--></para>
<para>Take care <emphasis>NOT</emphasis> to use
@ -39,22 +87,22 @@ strip --strip-unneeded /tools/bin/*</userinput></screen>
ones would be destroyed and the toolchain packages would need to be
built all over again.</para>
<para>To save more space, remove the documentation:</para>
<para>To save more space (about 37 MB), remove the documentation:</para>
<screen><userinput>rm -rf /usr/{,share}/{info,man,doc}</userinput></screen>
<screen role="nodump"><userinput>rm -rf $LFS/usr/share/{info,man,doc}</userinput></screen>
<para>The libtool .la files are only useful when linking with static
libraries. They are unneeded, and potentially harmful, when using dynamic
shared libraries, specially when using non-autotools build systems.
Remove those files now:</para>
<screen><userinput>find /usr/{lib,libexec} -name \*.la -delete</userinput></screen>
<screen role="nodump"><userinput>find $LFS/usr/{lib,libexec} -name \*.la -delete</userinput></screen>
<para>At this point, you should have at least 5 GB of free space on the
chroot partition 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. You can check the free disk space with the command
<command>df -h /</command>.</para>
<command>df -h $LFS/</command>.</para>
</sect2>
@ -68,29 +116,27 @@ strip --strip-unneeded /tools/bin/*</userinput></screen>
backed up for later reuse. In case of fatal failures in the subsequent
chapters, it often turns out that removing everything and starting over
(more carefully) is the best option to recover. Unfortunatly, all the
temporary tools will be removed, too. To avoid the extra time needed to redo
something which has been built successfully, prepare a backup.
temporary tools will be removed, too. To avoid spending extra time to
redo something which has been built successfully, prepare a backup.
</para>
<para>
Leave the chroot environment and make sure you have at least
600 MB free disk space (the source tarballs will be included in
the backup archive) in the home directory of user
<systemitem class="username">lfs</systemitem>. Leaving the
chroot environment is required as the backup should be stored
outside of the <filename class="directory">$LFS</filename> directory
but those cannot be accessed when in chroot. Leave the chroot environment
and unmount the virtual kernel filesystems:
Make sure you have at least 600 MB free disk space (the source tarballs
will be included in the backup archive) in the home directory of user
<systemitem class="username">root</systemitem>.
</para>
<screen role="nodump"><userinput>exit
umount $LFS/dev{/pts,}
umount $LFS/{sys,proc,run}</userinput></screen>
<para>Create the backup archive:</para>
<para>
Create the backup archive by running the following command:
</para>
<screen role="nodump"><userinput>cd $LFS &amp;&amp;
tar -cJpf $HOME/temp-tools.tar.xz .
</userinput></screen>
<para>
Replace <envar>$HOME</envar> by a directory of your choice if you
do not want to have the backup stored in <systemitem class="username">root</systemitem>'s
home directory.
</para>
<para>
In case some mistakes have been made and you need to start over, you can
@ -114,12 +160,13 @@ tar -xpf $HOME/temp-tools.tar.xz
<important>
<para>
If you left the chroot environment either to create a backup
or restart building using a restore, remember to mount the
kernel virtual filesystems as described in <xref
linkend='ch-tools-kernfs'/> and re-enter the
chroot environment (see <xref
linkend='ch-tools-chroot'/>) again before continuing.</para>
If you left the chroot environment either to strip off debug
symbols, create a backup or restart building using a restore,
remember to mount the kernel virtual filesystems now again as
described in <xref linkend='ch-tools-kernfs'/> and re-enter
the chroot environment (see <xref linkend='ch-tools-chroot'/>)
again before continuing.
</para>
</important>
</sect2>