source: chapter08/stripping.xml@ 63107f4

11.2 11.2-rc1 multilib s6-init trunk xry111/arm64 xry111/clfs-ng xry111/pip3 xry111/queue-11.3 xry111/rust-wip-20221008
Last change on this file since 63107f4 was 63107f4, checked in by Xi Ruoyao <xry111@…>, 8 months ago

fix typos

Suggested-by: rhubarbpieguy <rhubarbpieguy@…>

  • Property mode set to 100644
File size: 4.2 KB
Line 
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.</para></note>
46
47<!-- also of interest are libgfortan, libgo, libgomp, and libobjc from GCC -->
48
49<!--<screen><userinput>save_lib="ld-2.25.so libc-2.25.so libpthread-2.25.so libthread_db-1.0.so"-->
50<screen><userinput>save_usrlib="$(cd /usr/lib; ls ld-linux*)
51 libc.so.6
52 libthread_db.so.1
53 libquadmath.so.&libquadmath-version;
54 libstdc++.so.&libstdcpp-version;
55 libitm.so.&libitm-version;
56 libatomic.so.&libatomic-version;"
57
58cd /usr/lib
59
60for LIB in $save_usrlib; do
61 objcopy --only-keep-debug $LIB $LIB.dbg
62 cp $LIB /tmp/$LIB
63 strip --strip-unneeded /tmp/$LIB
64 objcopy --add-gnu-debuglink=$LIB.dbg /tmp/$LIB
65 install -vm755 /tmp/$LIB /usr/lib
66 rm /tmp/$LIB
67done
68
69online_usrbin="bash find strip"
70online_usrlib="libbfd-&binutils-version;.so
71 libhistory.so.&readline-soversion;
72 libncursesw.so.&ncurses-version;
73 libm.so.6
74 libreadline.so.&readline-soversion;
75 libz.so.&zlib-version;
76 $(cd /usr/lib; find libnss*.so* -type f)"
77
78for BIN in $online_usrbin; do
79 cp /usr/bin/$BIN /tmp/$BIN
80 strip --strip-unneeded /tmp/$BIN
81 install -vm755 /tmp/$BIN /usr/bin
82 rm /tmp/$BIN
83done
84
85for LIB in $online_usrlib; do
86 cp /usr/lib/$LIB /tmp/$LIB
87 strip --strip-unneeded /tmp/$LIB
88 install -vm755 /tmp/$LIB /usr/lib
89 rm /tmp/$LIB
90done
91
92for i in $(find /usr/lib -type f -name \*.so* ! -name \*dbg) \
93 $(find /usr/lib -type f -name \*.a) \
94 $(find /usr/{bin,sbin,libexec} -type f); do
95 case "$online_usrbin $online_usrlib $save_usrlib" in
96 *$(basename $i)* )
97 ;;
98 * ) strip --strip-unneeded $i
99 ;;
100 esac
101done
102
103unset BIN LIB save_usrlib online_usrbin online_usrlib
104</userinput></screen>
105
106 <para>A large number of files will be reported as having their file
107 format not recognized. These warnings can be safely ignored. They
108 indicate that those files are scripts instead of binaries.</para>
109
110</sect1>
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