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diff --git a/chapter07/stripping.xml b/chapter07/stripping.xml new file mode 100644 index 000000000..a31faadc3 --- /dev/null +++ b/chapter07/stripping.xml @@ -0,0 +1,188 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ + <!ENTITY % general-entities SYSTEM "../general.ent"> + %general-entities; +]> + +<sect1 id="ch-tools-stripping"> + <?dbhtml filename="stripping.html"?> + + <title>Finishing Temporary Tools</title> + + <para> + The steps in this section are optional. Skip this section entirely + if you are not really short on disk space and do not want to create + 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 are + 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> + + <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> + +<screen role="nodump"><userinput>exit +umount $LFS/dev{/pts,} +umount $LFS/{sys,proc,run}</userinput></screen> + + <sect2> + <title>Stripping</title> + + <para>If the LFS partition is rather small, it is good to + know that unnecessary items can be removed. The executables and + libraries built so far contain a little over 90 MB of unneeded debugging + symbols.</para> + + <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 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 + <parameter>--strip-unneeded</parameter> on the libraries. The static + ones would be destroyed and the toolchain packages would need to be + built all over again.</para> + + <para>To save more space (slightly more than 35 MB), remove the documentation:</para> + +<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 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 $LFS</command>.</para> + + </sect2> + + <sect2> + <title>Backup</title> + + <para> + Now that the essential tools have been created, its time to think about + a backup. When every check has passed successfully in the previously + built packages, your temporary tools are in a good state and might be + 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 spending extra time to + redo something which has been built successfully, prepare a backup. + </para> + + <para> + 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> + + <para> + Create the backup archive by running the following command: + </para> + +<screen role="nodump" revision="sysv"><userinput>cd $LFS && +tar -cJpf $HOME/lfs-temp-tools-&version;.tar.xz .</userinput></screen> + +<screen role="nodump" revision="systemd"><userinput>cd $LFS && +tar -cJpf $HOME/lfs-temp-tools-&versiond;.tar.xz .</userinput></screen> + + <para> + Replace <envar>$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> + </sect2> + + <sect2> + <title>Restore</title> + + <para> + In case some mistakes have been made and you need to start over, you can + use this backup to restore the temporary tools and save some recovery time. + Since the sources are located under + <filename class="directory">$LFS</filename>, they are included in the + backup archive as well, so they do not need to be downloaded again. After + checking that <filename class="directory">$LFS</filename> is set properly, + restore the backup by executing the following commands: + </para> + +<!-- Make the following look different so users don't blindly run the + restore when they don't need to. --> + +<screen role="nodump" revision="sysv"><computeroutput>cd $LFS && +rm -rf ./* && +tar -xpf $HOME/lfs-temp-tools-&version;.tar.xz</computeroutput></screen> + +<screen role="nodump" revision="systemd"><computeroutput>cd $LFS && +rm -rf ./* && +tar -xpf $HOME/lfs-temp-tools-&versiond;.tar.xz</computeroutput></screen> + + <para> + Again, double check that the environment has been setup properly + and continue building the rest of the system. + </para> + + <important> + <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> + +</sect1> |