strippingagain.xml 3.5 KB

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  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. <sect1 id="ch-system-strippingagain">
  8. <?dbhtml filename="strippingagain.html"?>
  9. <title>Stripping Again</title>
  10. <para>This section is optional. If the intended user is not a
  11. programmer and does not plan to do
  12. any debugging on the system software, the system size can be decreased
  13. by about 90 MB by removing the debugging symbols from binaries and
  14. libraries. This causes no inconvenience other than not being able to
  15. debug the software fully anymore.</para>
  16. <para>Most people who use the commands mentioned below do not
  17. experience any difficulties. However, it is easy to make a typo and
  18. render the new system unusable, so before running the
  19. <command>strip</command> commands, it is a good idea to make a
  20. backup of the LFS system in its current state.</para>
  21. <para>First place the debugging symbols for selected libraries
  22. in separate files. This debugging information is needed if running
  23. regression tests that use <ulink
  24. url='&blfs-book;/general/valgrind.html'>valgrind</ulink> or <ulink
  25. url='&blfs-book;/general/gdb.html'>gdb</ulink> later in BLFS.
  26. </para>
  27. <!-- also of interest are libgfortan, libgo, libgomp, and libobjc from gcc -->
  28. <!--<screen><userinput>save_lib="ld-2.25.so libc-2.25.so libpthread-2.25.so libthread_db-1.0.so"-->
  29. <screen><userinput>save_lib="ld-&glibc-version;.so libc-&glibc-version;.so libpthread-&glibc-version;.so libthread_db-&libthread_db-version;.so"
  30. cd /lib
  31. for LIB in $save_lib; do
  32. objcopy --only-keep-debug $LIB $LIB.dbg
  33. strip --strip-unneeded $LIB
  34. objcopy --add-gnu-debuglink=$LIB.dbg $LIB
  35. done
  36. save_usrlib="libquadmath.so.&libquadmath-version; libstdc++.so.&libstdcpp-version;
  37. libmpx.so.&libmpx-version; libmpxwrappers.so.&libmpxwrap-version; libitm.so.&libitm-version;
  38. libcilkrts.so.&libcilkrts-version; libatomic.so.&libatomic-version;"
  39. cd /usr/lib
  40. for LIB in $save_usrlib; do
  41. objcopy --only-keep-debug $LIB $LIB.dbg
  42. strip --strip-unneeded $LIB
  43. objcopy --add-gnu-debuglink=$LIB.dbg $LIB
  44. done
  45. unset LIB save_lib save_usrlib</userinput></screen>
  46. <para>Before performing the stripping, take special care to ensure that
  47. none of the binaries that are about to be stripped are running. If
  48. unsure whether the user entered chroot with the command given in
  49. <xref linkend="ch-system-chroot" role=","/> first exit from
  50. chroot:</para>
  51. <screen role="nodump"><userinput>logout</userinput></screen>
  52. <para>Then reenter it with:</para>
  53. <screen role="nodump"><userinput>chroot $LFS /tools/bin/env -i \
  54. HOME=/root TERM=$TERM PS1='\u:\w\$ ' \
  55. PATH=/bin:/usr/bin:/sbin:/usr/sbin \
  56. /tools/bin/bash --login</userinput></screen>
  57. <para>Now the binaries and libraries can be safely stripped:</para>
  58. <screen><userinput>/tools/bin/find /usr/lib -type f -name \*.a \
  59. -exec /tools/bin/strip --strip-debug {} ';'
  60. /tools/bin/find /lib /usr/lib -type f \( -name \*.so* -a ! -name \*dbg \) \
  61. -exec /tools/bin/strip --strip-unneeded {} ';'
  62. /tools/bin/find /{bin,sbin} /usr/{bin,sbin,libexec} -type f \
  63. -exec /tools/bin/strip --strip-all {} ';'</userinput></screen>
  64. <para>A large number of files will be reported as having their file
  65. format not recognized. These warnings can be safely ignored. These
  66. warnings indicate that those files are scripts instead of
  67. binaries.</para>
  68. </sect1>