1 | <?xml version="1.0" encoding="ISO-8859-1"?>
|
---|
2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
|
---|
3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
|
---|
4 | <!ENTITY % general-entities SYSTEM "../general.ent">
|
---|
5 | %general-entities;
|
---|
6 | ]>
|
---|
7 |
|
---|
8 | <sect1 id="ch-system-stripping">
|
---|
9 | <?dbhtml filename="stripping.html"?>
|
---|
10 |
|
---|
11 | <title>Stripping</title>
|
---|
12 |
|
---|
13 | <para>This section is optional. If the intended user is not a
|
---|
14 | programmer and does not plan to do
|
---|
15 | any debugging on the system software, the system size can be decreased
|
---|
16 | by about 2 GB by removing the debugging symbols from binaries and
|
---|
17 | libraries. This causes no inconvenience other than not being able to
|
---|
18 | debug the software fully anymore.</para>
|
---|
19 |
|
---|
20 | <para>Most people who use the commands mentioned below do not
|
---|
21 | experience any difficulties. However, it is easy to make a typo and
|
---|
22 | render the new system unusable, so before running the
|
---|
23 | <command>strip</command> commands, it is a good idea to make a
|
---|
24 | backup of the LFS system in its current state.</para>
|
---|
25 |
|
---|
26 | <para>The debugging symbols for selected libraries are placed
|
---|
27 | in separate files. This debugging information is needed if running
|
---|
28 | regression tests that use <ulink
|
---|
29 | url='&blfs-book;/general/valgrind.html'>valgrind</ulink> or <ulink
|
---|
30 | url='&blfs-book;/general/gdb.html'>gdb</ulink> later in BLFS.
|
---|
31 | </para>
|
---|
32 |
|
---|
33 | <para>Note that <command>strip</command> will overwrite the binary or library
|
---|
34 | file it is processing. This can crash the processes using code or data from
|
---|
35 | the file. If the process running <command>strip</command> itself is
|
---|
36 | affected, the binary or library being stripped can be destroyed and can
|
---|
37 | make the system completely unusable. To avoid it, we'll copy some libraries
|
---|
38 | and binaries into <filename class="directory">/tmp</filename>, strip them
|
---|
39 | there, and install them back with the <command>install</command> command.
|
---|
40 | Read the related entry in <xref linkend="pkgmgmt-upgrade-issues"/> for the
|
---|
41 | rationale to use the <command>install</command> command here.</para>
|
---|
42 |
|
---|
43 | <note><para>The ELF loader's name is ld-linux-x86-64.so.2 on 64-bit systems
|
---|
44 | and ld-linux.so.2 on 32-bit systems. The construct below selects the
|
---|
45 | correct name for the current architecture, excluding anything ending
|
---|
46 | with <quote>g</quote>, in case the commands below have already been
|
---|
47 | run.</para></note>
|
---|
48 |
|
---|
49 | <!-- also of interest are libgfortan, libgo, libgomp, and libobjc from GCC -->
|
---|
50 |
|
---|
51 | <!--<screen><userinput>save_lib="ld-2.25.so libc-2.25.so libpthread-2.25.so libthread_db-1.0.so"-->
|
---|
52 | <screen><userinput>save_usrlib="$(cd /usr/lib; ls ld-linux*[^g])
|
---|
53 | libc.so.6
|
---|
54 | libthread_db.so.1
|
---|
55 | libquadmath.so.&libquadmath-version;
|
---|
56 | libstdc++.so.&libstdcpp-version;
|
---|
57 | libitm.so.&libitm-version;
|
---|
58 | libatomic.so.&libatomic-version;"
|
---|
59 |
|
---|
60 | cd /usr/lib
|
---|
61 |
|
---|
62 | for LIB in $save_usrlib; do
|
---|
63 | objcopy --only-keep-debug $LIB $LIB.dbg
|
---|
64 | cp $LIB /tmp/$LIB
|
---|
65 | strip --strip-unneeded /tmp/$LIB
|
---|
66 | objcopy --add-gnu-debuglink=$LIB.dbg /tmp/$LIB
|
---|
67 | install -vm755 /tmp/$LIB /usr/lib
|
---|
68 | rm /tmp/$LIB
|
---|
69 | done
|
---|
70 |
|
---|
71 | online_usrbin="bash find strip"
|
---|
72 | online_usrlib="libbfd-&binutils-version;.so
|
---|
73 | libhistory.so.&readline-soversion;
|
---|
74 | libncursesw.so.&ncurses-version;
|
---|
75 | libm.so.6
|
---|
76 | libreadline.so.&readline-soversion;
|
---|
77 | libz.so.&zlib-version;
|
---|
78 | $(cd /usr/lib; find libnss*.so* -type f)"
|
---|
79 |
|
---|
80 | for BIN in $online_usrbin; do
|
---|
81 | cp /usr/bin/$BIN /tmp/$BIN
|
---|
82 | strip --strip-unneeded /tmp/$BIN
|
---|
83 | install -vm755 /tmp/$BIN /usr/bin
|
---|
84 | rm /tmp/$BIN
|
---|
85 | done
|
---|
86 |
|
---|
87 | for LIB in $online_usrlib; do
|
---|
88 | cp /usr/lib/$LIB /tmp/$LIB
|
---|
89 | strip --strip-unneeded /tmp/$LIB
|
---|
90 | install -vm755 /tmp/$LIB /usr/lib
|
---|
91 | rm /tmp/$LIB
|
---|
92 | done
|
---|
93 |
|
---|
94 | for i in $(find /usr/lib -type f -name \*.so* ! -name \*dbg) \
|
---|
95 | $(find /usr/lib -type f -name \*.a) \
|
---|
96 | $(find /usr/{bin,sbin,libexec} -type f); do
|
---|
97 | case "$online_usrbin $online_usrlib $save_usrlib" in
|
---|
98 | *$(basename $i)* )
|
---|
99 | ;;
|
---|
100 | * ) strip --strip-unneeded $i
|
---|
101 | ;;
|
---|
102 | esac
|
---|
103 | done
|
---|
104 |
|
---|
105 | unset BIN LIB save_usrlib online_usrbin online_usrlib
|
---|
106 | </userinput></screen>
|
---|
107 |
|
---|
108 | <para>A large number of files will be reported as having their file
|
---|
109 | format not recognized. These warnings can be safely ignored. They
|
---|
110 | indicate that those files are scripts instead of binaries.</para>
|
---|
111 |
|
---|
112 | </sect1>
|
---|