source: chapter08/strippingagain.xml@ d1592b9

11.0 11.0-rc1 11.0-rc2 11.0-rc3 11.1 11.1-rc1 arm ml-11.0 multilib s6-init trunk xry111/clfs-ng xry111/glibc-2.34 xry111/lfs-next
Last change on this file since d1592b9 was d1592b9, checked in by Xi Ruoyao <xry111@…>, 13 months ago

stripping: add libnss_*.so* into online_usrlib

Glibc loads these "NSS modules" (see man 5 nss) on startup. This is
implemented with something like dlopen() so "ldd" won't show them up.
So they should be considered "online" here.

Without this addition, overwriting libnss_files-2.33.so reproducibly
triggers a crash during jhalfs runs where stripping is enabled. In
manual builds, it reproducibly triggers a crash exiting from chroot.

After this change I reran stripping 5 times and there was no crash
observed.

  • 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-strippingagain">
9 <?dbhtml filename="strippingagain.html"?>
10
11 <title>Stripping Again</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. These 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>And, <command>strip</command> will overwrite the binary or library
34 file. This may crash the processes using code or data from the file. If
35 the process running <command>strip</command> itself is affected, the
36 binary or library being stripped may be destroyed. This may make the
37 system completely unusable. To avoid it, we'll copy some libraries and
38 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<!-- also of interest are libgfortan, libgo, libgomp, and libobjc from GCC -->
44
45<!--<screen><userinput>save_lib="ld-2.25.so libc-2.25.so libpthread-2.25.so libthread_db-1.0.so"-->
46<screen><userinput>save_usrlib="ld-&glibc-version;.so libc-&glibc-version;.so libpthread-&glibc-version;.so libthread_db-&libthread_db-version;.so
47 libquadmath.so.&libquadmath-version; libstdc++.so.&libstdcpp-version;
48 libitm.so.&libitm-version; libatomic.so.&libatomic-version;" <!-- libcilkrts.so.&libcilkrts-version;-->
49
50cd /usr/lib
51
52for LIB in $save_usrlib; do
53 objcopy --only-keep-debug $LIB $LIB.dbg
54 cp $LIB /tmp/$LIB
55 strip --strip-unneeded /tmp/$LIB
56 objcopy --add-gnu-debuglink=$LIB.dbg /tmp/$LIB
57 install -vm755 /tmp/$LIB /usr/lib
58 rm /tmp/$LIB
59done
60
61online_usrbin="bash find strip"
62online_usrlib="libbfd-&binutils-version;.so libdl-&glibc-version;.so
63 libhistory.so.&readline-version; libncursesw.so.&ncurses-version;
64 libm-&glibc-version;.so libreadline.so.&readline-version;
65 libz.so.&zlib-version;
66 $(cd /usr/lib; find libnss*.so* -type f)"
67
68for BIN in $online_usrbin; do
69 cp /usr/bin/$BIN /tmp/$BIN
70 strip --strip-all /tmp/$BIN
71 install -vm755 /tmp/$BIN /usr/bin
72 rm /tmp/$BIN
73done
74
75for LIB in $online_usrlib; do
76 cp /usr/lib/$LIB /tmp/$LIB
77 strip --strip-unneeded /tmp/$LIB
78 install -vm755 /tmp/$LIB /usr/lib
79 rm /tmp/$LIB
80done
81
82find /usr/lib -type f -name \*.a \
83 -exec strip --strip-debug {} ';'
84
85for i in $(find /usr/lib -type f -name \*.so* ! -name \*dbg); do
86 case "$online_usrlib $save_usrlib" in
87 *$(basename $i)* ) ;;
88 * ) strip --strip-unneeded $i ;;
89 esac
90done
91
92for i in $(find /usr/bin -type f); do
93 case "$online_usrbin" in
94 *$(basename $i)* ) ;;
95 * ) strip --strip-all $i ;;
96 esac
97done
98
99find /usr/{sbin,libexec} -type f \
100 -exec strip --strip-all {} ';'
101
102unset BIN LIB save_usrlib online_usrbin online_usrlib
103</userinput></screen>
104
105 <para>A large number of files will be reported as having their file
106 format not recognized. These warnings can be safely ignored. These
107 warnings indicate that those files are scripts instead of
108 binaries.</para>
109
110</sect1>
Note: See TracBrowser for help on using the repository browser.