About:
UPX is a portable, extendable, high-performance executable packer for several different executable formats. It achieves an excellent compression ratio and offers very fast decompression. Your executables suffer no memory overhead or other drawbacks. UPX supports vmlinuz/386, linux/elf386, linux/386, win32/pe, dos/exe, djgpp2/coff, and many more.

Author:
mfx [contact developer]

Rating:	reset 1 2 3 4 5 6 7 8 9 10
8.69/10.00 (7 votes)

Homepage:
http://upx.sourceforge.net/
Tar/GZ:
http://upx.sourceforge.net/#download
Zip:
http://upx.sourceforge.net/#download
Changelog:
http://upx.sourceforge.net/upx-news.txt
RPM package:
http://fr.rpmfind.net/linux/rpm2html/search.php?query=upx
Debian package:
http://packages.debian.org/upx-ucl

Trove categories: [change]

[Development Status]		5 - Production/Stable
[Environment]		Console (Text Based)
[Intended Audience]		End Users/Desktop, System Administrators
[License]		OSI Approved :: GNU General Public License (GPL)
[Operating System]		POSIX
[Programming Language]		Assembly, C++
[Topic]		System :: Archiving :: Compression, System :: Boot

Dependencies: [change]
No dependencies filed

 Branches

Branch	Version	Last release	License	URLs
Stable	1.25	29-Jun-2004	GNU General Public License (GPL)
Unstable	2.90	10-Oct-2006	GNU General Public License (GPL)

 Comments

[»] magic file patch
by jay unbound - May 13th 1999 12:48:28

here's a patch for your magic file (usually /usr/share/magic) to allow file(1) to do simple recognition of UPX compressed executables. with this patch, running file on a UPX compressed executable you get the following (example) output:

$ file ./gimp
./gimp: ELF 32-bit LSB executable, UPX compressed, Intel 80386, version 1,
statically linked, stripped

# upx.magic.patch
#
# apply this patch to /usr/share/magic to allow file(1) to have simple
#   recognition of UPX (http://wildsau.idv.uni-linz.ac.at/mfx/upx.html)
#   compressed executables
# do (with permissions to write to magic [eg. as root]): 
# cp upx.magic.patch /usr/share && cd /usr/share && patch <
upx.magic.patch
*** magic.old	Sat May  8 04:49:47 1999
--- magic	Thu May 13 18:02:18 1999
***************
*** 1351,1356 ****
--- 1351,1358 ----
  # What're the correct byte orders for the nCUBE and the Fujitsu VPP500?
  #
  # updated by Daniel Quinlan (quinlan@yggdrasil.com)
+ # UPX (http://wildsau.idv.uni-linz.ac.at/mfx/upx.html) support added
+ #   by Jay Johnston (jajohnst@cs.vassar.edu)
  0	string		\177ELF		ELF
  >4	byte		0		invalid class
  >4	byte		1		32-bit
***************
*** 1360,1365 ****
--- 1362,1368 ----
  >>16	leshort		0		no file type,
  >>16	leshort		1		relocatable,
  >>16	leshort		2		executable,
+ >>>154  string		UPX		UPX compressed,
  >>16	leshort		3		shared object,
  # Core handling from Peter Tobias 
  # corrections by Christian 'Dr. Disk' Hechelmann

[reply] [top]

[»] PowerPC support?
by Jeremy Friesner - Jan 9th 2004 10:13:04

This program would be just the ticket for getting more mileage out of my embedded PowerPC linux card's flash ram storage... but it appears that PowerPC executables are not supported. Any chance of support for PowerPC executables being added soon? (my project uses the 2.4 kernel, fwiw)

[reply] [top]

---

[»] whoa there...
by jay unbound - May 13th 1999 12:21:55

To quote your description of UPX on Freshmeat (see the top of this page) and at the top of your documentation for UPX:

"Your executables [when compressed with UPX] suffer no memory overhead or other drawbacks"

While UPX excels at its function, it does create drawbacks for the executables it compresses. I was just clarifying that for those looking at the freshmeat description of UPX (using the comments section for what it's there for).

Furthermore, UPX is a closed-source program, so the only way one in the Linux community can help others in regards to UPX's drawbacks is to spread the knowledge of those drawbacks (as opposed to helping to solve them as one would do if the program was Open Source and gpl'd).

[reply] [top]

[»] Re: damn smooth, but some does have some problems...
by mfx - May 13th 1999 05:28:49

To quote the documentation:

Drawbacks:

  - `ldd' and `size' won't show anything useful because all they
    see is the statically linked stub.
 
  ...

[reply] [top]

[»] damn smooth, but some does have some problems...
by jay unbound - Apr 24th 1999 11:27:43

damn! this util is amazing!!! it does exactly what it says...and real well:

$ cp gimp gimp.upx
$ upx gimp.upx 
                     Ultimate Packer for eXecutables
                  Copyright (C) 1996, 1997, 1998, 1999
UPX v0.71        Markus F.X.J. Oberhumer & Laszlo Molnar        Apr 19th
1999

        File size        Ratio      Format      Name
   -------------------   ------   -----------   -----------
   1252148 ->   513408   41.00%   linux/i386    gimp.upx                  
    

Packed 1 file.

$ ls -fl gimp gimp.upx 
-rwxr-xr-x   1 jajohnst users     1252148 Apr 21 23:23 gimp
-rwxr-xr-x   1 jajohnst users      513408 Apr 24 13:56 gimp.upx

$ file ./gimp
./gimp: ELF 32-bit LSB executable, Intel 80386, version 1, dynamically
linked, stripped
$ file ./gimp.upx 
./gimp.upx: ELF 32-bit LSB executable, Intel 80386, version 1, statically
linked, stripped

$ mv /usr/lib/libgtk-1.2.so.0 /usr/lib/libgtk-1.2.so.0.bak
$ ./gimp.upx 
./gimp.upx: error in loading shared libraries
libgtk-1.2.so.0: cannot open shared object file: No such file or
directory

$ ldd ./gimp.upx
        not a dynamic executable

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[»] Kernel packing rocks
by Mark Robson - Nov 13th 2002 08:02:22

The unstable version 1.90 supports kernel packing - this is excellent for single-disc distributions where every k counts. My kernel decreased in size 20% after upx, and bear in mind that bzImage kernels are in fact compressed with gzip *already* - so it actually beat the existing compression by quite a big margin. The kernel still boots fine, in fact quicker than it did before.

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