source: chapter08/stripping.xml@ 051c160

multilib
Last change on this file since 051c160 was 051c160, checked in by Thomas Trepl (Moody) <thomas@…>, 6 months ago

Automatic merge of trunk into multilib

  • Property mode set to 100644
File size: 5.8 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
59for LIB in $save_usrlib; do
60 objcopy --only-keep-debug $LIB $LIB.dbg
61 cp $LIB /tmp/$LIB
62 strip --strip-unneeded /tmp/$LIB
63 objcopy --add-gnu-debuglink=$LIB.dbg /tmp/$LIB
64 install -vm755 /tmp/$LIB /usr/lib
65 rm /tmp/$LIB
66done</userinput>
67<userinput arch="ml_32,ml_all">
68cd /usr/lib32
69for LIB in $save_usrlib; do
70 objcopy --only-keep-debug $LIB $LIB.dbg
71 cp $LIB /tmp/$LIB
72 strip --strip-unneeded /tmp/$LIB
73 objcopy --add-gnu-debuglink=$LIB.dbg /tmp/$LIB
74 install -vm755 /tmp/$LIB /usr/lib32
75 rm /tmp/$LIB
76done</userinput>
77<userinput arch="ml_x32,ml_all">
78cd /usr/libx32
79for LIB in $save_usrlib; do
80 objcopy --only-keep-debug $LIB $LIB.dbg
81 cp $LIB /tmp/$LIB
82 strip --strip-unneeded /tmp/$LIB
83 objcopy --add-gnu-debuglink=$LIB.dbg /tmp/$LIB
84 install -vm755 /tmp/$LIB /usr/libx32
85 rm /tmp/$LIB
86done</userinput><userinput>
87
88online_usrbin="bash find strip"
89online_usrlib="libbfd-&binutils-version;.so
90 libhistory.so.&readline-soversion;
91 libncursesw.so.&ncurses-version;
92 libm.so.6
93 libreadline.so.&readline-soversion;
94 libz.so.&zlib-version;
95 $(cd /usr/lib; find libnss*.so* -type f)"
96
97for BIN in $online_usrbin; do
98 cp /usr/bin/$BIN /tmp/$BIN
99 strip --strip-unneeded /tmp/$BIN
100 install -vm755 /tmp/$BIN /usr/bin
101 rm /tmp/$BIN
102done
103
104for LIB in $online_usrlib; do
105 cp /usr/lib/$LIB /tmp/$LIB
106 strip --strip-unneeded /tmp/$LIB
107 install -vm755 /tmp/$LIB /usr/lib
108 rm /tmp/$LIB
109done</userinput><userinput arch="ml_32,ml_all">
110for LIB in $online_usrlib; do
111 cp /usr/lib32/$LIB /tmp/$LIB
112 strip --strip-unneeded /tmp/$LIB
113 install -vm755 /tmp/$LIB /usr/lib32
114 rm /tmp/$LIB
115done</userinput><userinput arch="ml_x32,ml_all">
116for LIB in $online_usrlib; do
117 cp /usr/libx32/$LIB /tmp/$LIB
118 strip --strip-unneeded /tmp/$LIB
119 install -vm755 /tmp/$LIB /usr/libx32
120 rm /tmp/$LIB
121done</userinput><userinput>
122
123for i in $(find /usr/lib -type f -name \*.so* ! -name \*dbg) \
124 $(find /usr/lib -type f -name \*.a) \
125 $(find /usr/{bin,sbin,libexec} -type f); do
126 case "$online_usrbin $online_usrlib $save_usrlib" in
127 *$(basename $i)* )
128 ;;
129 * ) strip --strip-unneeded $i
130 ;;
131 esac
132done</userinput><userinput arch="ml_32,ml_all">
133for i in $(find /usr/lib32 -type f -name \*.so* ! -name \*dbg); do
134 case "$online_usrbin $online_usrlib $save_usrlib" in
135 *$(basename $i)* )
136 ;;
137 * ) strip --strip-unneeded $i
138 ;;
139 esac
140done</userinput><userinput arch="ml_x32,ml_all">
141for i in $(find /usr/libx32 -type f -name \*.so* ! -name \*dbg); do
142 case "$online_usrbin $online_usrlib $save_usrlib" in
143 *$(basename $i)* )
144 ;;
145 * ) strip --strip-unneeded $i
146 ;;
147 esac
148done</userinput><userinput>
149
150unset BIN LIB save_usrlib online_usrbin online_usrlib
151</userinput></screen>
152
153 <para>A large number of files will be reported as having their file
154 format not recognized. These warnings can be safely ignored. They
155 indicate that those files are scripts instead of binaries.</para>
156
157</sect1>
Note: See TracBrowser for help on using the repository browser.