Stripping ELF .note and .comment sections?

[Topi Miettinen <Topi.Miettinen@ml.tele.fi>]

ELF objects may contain sections .note and .comment, which are not needed.
Gcc puts compiler version to .comment and "01.01" to .note section. The
sections may be examined like this:

$ objdump --section=.note --full-contents /bin/cp

/bin/cp:     file format elf32-i386

Contents of section .note:
 0190 08000000 00000000 01000000 30312e30  ............01.0
 01a0 31000000 08000000 00000000 01000000  1...............
 01b0 30312e30 31000000 08000000 00000000  01.01...........
[cut]

Same for .comment:
[cut}
 0000 00474343 3a202847 4e552920 322e372e  .GCC: (GNU) 2.7.
 0010 322e3100 00474343 3a202847 4e552920  2.1..GCC: (GNU) 
 0020 322e372e 322e3300 00474343 3a202847  2.7.2.3..GCC: (G
[cut]

These sections just take up disk space. They can be stripped with

$ objcopy --remove-section=.comment --remove-section=.note /usr/X11R6/bin/XF86_SVGA xf
$ du /usr/X11R6/bin/XF86_SVGA xf
2652    /usr/X11R6/bin/XF86_SVGA
2623    xf

29k disk space saved (1%). Savings depend on size of compile-time *.o files
vs their number, for example for cp that is 4%.

Compiler version information could be useful (to detect old compiler
output), but that is already in /usr/doc/foo/buildinfo.Debian and the
version in .comment does not specify entire Debian version.

BugReportWarning: If this is added to Policy (section 3.3.1?), inspecting
ELF sections is trivial to add to lintian. ;-)

-Topi




--
To UNSUBSCRIBE, email to debian-policy-request@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org