- WIMLIB
+ WIMLIB
-This is wimlib version 0.7.1 (May 2012). wimlib can be used to read, write,
-and mount files in the Windows Imaging Format (WIM files). These files are
-normally created by using the `imagex.exe' utility on Windows, but this library
-provides a free implementetion of imagex for UNIX-based systems.
+This is wimlib version 1.2.5 (February 2013). wimlib can be used to read,
+write, and mount files in the Windows Imaging Format (WIM files). These files
+are normally created by using the `imagex.exe' utility on Windows, but this
+library provides a free implementation of imagex for UNIX-based systems.
-The main use of this library is to create customized images of Windows PE, the
-Windows Preinstallation Environment, without having to rely on Windows. Windows
-PE is a lightweight version of Windows that can run entirely from memory and can
-be used to install Windows from local media or a network drive or perform
-maintenance. Windows PE is the operating systems runs when you boot from the
-Windows DVD.
+ WIM FILES
+
+A Windows Imaging (WIM) file is an archive. Like some other archive formats
+such as ZIP, files in WIM archives may be compressed. WIM archives support two
+Microsoft-specific compression formats: LZX and XPRESS. Both are based on LZ77
+and Huffman encoding, and both are supported by wimlib.
+
+Unlike ZIP files, WIM files can contain multiple independent toplevel directory
+trees known as images. While each image has its own metadata describing a
+directory tree and file access modes, files are not duplicated for each image;
+instead, each file is included only once in the entire WIM. Microsoft did this
+so that in one WIM file, they could do things like have 5 different versions of
+Windows that are almost exactly the same.
+
+Microsoft provides documentation for the WIM file format, XPRESS compression
+format, and LZX compression format. The XPRESS documentation is acceptable, but
+the LZX documentation is not entirely correct, and the WIM documentation itself
+is incomplete.
-You can find Windows PE on the ISO filesystem on the installation DVD for both
-Windows 7 and Windows 8. I don't have a DVD for Vista but it should be on there
-too. The Windows PE image a WIM file, `sources/boot.wim', on the ISO
-filesystem. Windows PE can also be found in the Windows Automated Installation
-Kit (WAIK), which is free to download from Microsoft, inside the `WinPE.cab'
-file, which you can extract if you install the `cabextract' program.
+A WIM file may be either stand-alone or split into multiple parts.
+
+ PROGRAMS
wimlib provides a public API for other programs to use, but also comes with two
-programs: `imagex' and `mkwinpeimg'.
+programs: `imagex' and `mkwinpeimg'.
`imagex' is intended to be like the imagex.exe program from Windows. `imagex'
can be used to create, extract, and mount WIM files. Both read-only and
`mkwinpeimg' is shell script that makes it easy to create a customized bootable
image of Windows PE that can be put on a CD or USB drive, or published on a
-server for PXE booting. See the main page `doc/mkwinpeiso.1' for more details.
+server for PXE booting. See the main page `doc/mkwinpeimg.1' for more details.
-Wimlib can also be used to handle larger WIM files such as the `install.wim'
-file that comes on the Windows DVD; however, this has not been well tested.
+There is an additional program, `wimapply', that is not installed by default.
+It can be used to build a small executable with the ability to apply a WIM image
+from a standalone WIM, without having to build the whole shared library. This
+could be useful on Linux boot clients that only need to be able to apply a WIM,
+not capture/split/join/append/export/mount a WIM. See `programs/wimapply.c'.
-An earlier version of Wimlib is being used to deploy Windows 7 from the Ultimate
-Deployment Appliance. For more information see
-http://www.ultimatedeployment.org/.
+ COMPRESSION RATIO
+
+wimlib can create XPRESS or LZX compressed WIM archives. Currently, the XPRESS
+compression ratio is slightly better than that provided by Microsoft's software,
+while the LZX compression ratio is approaching that of Microsoft's software but
+is not quite there yet. Running time is as good as or better than Microsoft's
+software, especially with multithreaded compression, available in wimlib v1.1.0
+and later.
+
+The following tables compare the compression ratio and performance for creating
+a compressed Windows PE image (disk usage of about 524 MB, uncompressed WIM size
+361 MB):
+
+ Table 1. WIM size
+
+ XPRESS Compression LZX Compression
+ wimlib imagex (v1.2.1): 138,971,353 bytes 131,379,943 bytes
+ Microsoft imagex.exe: 140,406,981 bytes 127,249,176 bytes
+
+ Table 2. Time to create WIM
+
+ XPRESS Compression LZX Compression
+ wimlib imagex (v1.2.1, 2 threads): 11 sec 17 sec
+ Microsoft imagex.exe: 25 sec 89 sec
+
+ NTFS SUPPORT
+
+As of version 1.0.0, wimlib supports capturing and applying images directly to
+NTFS volumes. This was made possible with the help of libntfs-3g from the
+NTFS-3g project. This feature supports capturing and restoring NTFS-specific
+data such as security descriptors, alternate data streams, and reparse point
+data.
+
+The code for NTFS image capture and image application is complete enough that it
+is possible to apply an image from the "install.wim" contained in recent Windows
+installation media (Vista, Windows 7, or Windows 8) directly to a NTFS volume,
+and then boot Windows from it after preparing the Boot Configuration Data. In
+addition, a Windows installation can be captured (or backed up) into a WIM file,
+and then re-applied later.
+
+ WINDOWS PE
+
+A major use for this library is to create customized images of Windows PE, the
+Windows Preinstallation Environment, without having to rely on Windows. Windows
+PE is a lightweight version of Windows that can run entirely from memory and can
+be used to install Windows from local media or a network drive or perform
+maintenance. Windows PE is the operating system that runs when you boot from
+the Windows installation media.
+
+You can find Windows PE on the installation DVD for Windows Vista, Windows 7, or
+Windows 8, in the file `sources/boot.wim'. Windows PE can also be found in the
+Windows Automated Installation Kit (WAIK), which is free to download from
+Microsoft, inside the `WinPE.cab' file, which you can extract if you install
+either the `cabextract' or `p7zip' programs.
--------------------------------------------------------------------------------
+In addition, Windows installations and recovery partitions frequently contain a
+WIM containing an image of the Windows Recovery Environment, which is similar to
+Windows PE.
+
+ DEPENDENCIES
+
+* libxml2 (required)
+ This is a commonly used free library to read and write XML files. You
+ likely already have it installed as a dependency for some other program.
+ For more information see http://xmlsoft.org/.
+
+* libfuse (optional but highly recommended)
+ Unless configured with --without-fuse, wimlib requires a non-ancient
+ version of libfuse to be installed. Most GNU/Linux distributions
+ already include this, but make sure you have the libfuse package
+ installed, and also libfuse-dev if your distribution distributes header
+ files separately. FUSE also requires a kernel module. If the kernel
+ module is available it will automatically be loaded if you try to mount
+ a WIM file. For more information see http://fuse.sourceforge.net/.
+ FUSE is also available for FreeBSD.
+
+* libntfs-3g (optional but highly recommended)
+ Unless configured with --without-ntfs-3g, wimlib requires the library
+ and headers for libntfs-3g version 2011-4-12 or later to be installed.
+ Versions dated 2010-3-6 and earlier do not work because they are missing
+ the header xattrs.h (and the file xattrs.c, which contains functions we
+ need). libntfs-3g version 2013-1-13 is compatible only with wimlib
+ 1.2.4 and later.
+
+* OpenSSL / libcrypto (optional)
+ wimlib can use the SHA1 message digest code from OpenSSL instead of
+ compiling in yet another SHA1 implementation. (See LICENSE section.)
+
+* cdrkit (optional)
+* mtools (optional)
+* syslinux (optional)
+* cabextract (optional)
+ The `mkwinpeimg' shell script will look for several other programs
+ depending on what options are given to it. Depending on your GNU/Linux
+ distribution, you may already have these programs installed, or they may
+ be in the software repository. Making an ISO filesystem requires
+ `mkisofs' from `cdrkit' (http://www.cdrkit.org). Making a disk image
+ requires `mtools' (http://www.gnu.org/software/mtools) and `syslinux'
+ (http://www.syslinux.org). Retrieving files from the Windows Automated
+ Installation Kit requires `cabextract' (http://www.cabextract.org.uk).
CONFIGURATION
Besides the various well-known options, the following options can be passed to
wimlib's `configure' script:
+--without-ntfs-3g
+ If libntfs-3g is not available or is not version 2011-4-12 or later,
+ wimlib can be built without it, in which case it will not be possible to
+ apply or capture images directly to/from NTFS volumes.
+
--without-fuse
If libfuse or the FUSE kernel module is not available, wimlib can be
compiled with --without-fuse. This will remove the ability to mount and
- unmount WIM files. wimlib_mount() and wimlib_unmount() will fail with
- WIMLIB_ERR_UNSUPPORTED.
+ unmount WIM files.
--without-libcrypto
Build in functions for SHA1 rather than using external SHA1 functions
from libcrypto (part of OpenSSL). The default is to use libcrypto if it
is found on the system.
+--enable-xattr, --disable-xattr
+ Enable or disable support for the extended-attributes interface to NTFS
+ alternate data streams in mounted WIMs. To support these, wimlib
+ requires that the setxattr() function and the attr/xattr.h header are
+ available. The default is to autodetect whether support is possible.
+
+--disable-multithreaded-compression
+ By default, data will be compressed using multiple threads when writing
+ a WIM, unless only 1 processor is detected. Specify this option to
+ disable support for this.
+
--enable-ssse3-sha1
Use a very fast assembly language implementation of SHA1 from Intel.
Only use this if the build target supports the SSSE3 instructions.
--disable-custom-memory-allocator
- If this option is given, MALLOC(), FREE(), CALLOC(), and STRDUP() will
- directly call the appropriate functions in the C library.
- wimlib_set_memory_allocator() will fail with WIMLIB_ERR_UNSUPPORTED.
+ If this option is given, a very small amount of space will be saved by
+ removing support for the wimlib_set_memory_allocator() function. imagex
+ will be unaffected.
--disable-verify-compression
- Unless this option is given, every time wimlib compresses a data block
- it will decompress it into a temporary buffer and abort() the program
- with an error message if the decompressed data does not exactly match
- the original data. This is to find bugs.
-
---disable-security-data
- Wimlib cannot create or modify WIM security data, but by default it will
- copy existing security data when modifying a WIM or exporting an image.
- Passing this flag will disable this support; then wimlib will always
- write WIMs without security data.
+ Unless this option is given, every time wimlib compresses a data block,
+ it will decompress it into a temporary buffer and abort the program with
+ an error message if the decompressed data does not exactly match the
+ original data. This only makes compression about 10% slower. However,
+ this checking can probably be safely disabled because there are no known
+ bugs in the compression code, and the SHA1 message digest of every
+ extracted file is checked anyway.
--disable-error-messages
- Removes all error messages from the library. If left in, they still
- have to explicitly turned on with wimlib_set_print_errors() in order to
- see them. Also, error codes will still be returned regardless of
- whether error messages are printed or not.
-
- If --disable-error-messages is given, wimlib_set_print_errors() will
- fail with WIMLIB_ERR_UNSUPPORTED if the action is to turn error messages
- on.
+ Save some space by removing all error messages from the library.
--disable-assertions
- Remove all assertions. Without this option, wimlib will abort() the
- program if an assertion fails. An assertion failure should only occur
- if there is a bug in wimlib.
+ Remove all assertions, even the ones that are included by default.
+
+--enable-more-assertions
+ Enable assertions that are not included by default.
--enable-debug
Include debugging messages. Only use this option if you have found a
Include more debugging messages. Only use this option if you have found
a bug in the library.
-
--------------------------------------------------------------------------------
-
- DEPENDENCIES
-
-Wimlib requires libxml2 to build. This is a commonly used free library to read
-and write XML files. You likely already have it installed as a dependency for
-some other program. For more information see http://xmlsoft.org/.
-
-Wimlib also requires libfuse to build (unless configured with --without-fuse;
-see above). Most GNU/Linux distributions already include this, but make sure
-you have the libfuse package installed (libfuse-dev if your distribution
-distributes header files separately). FUSE also requires a kernel module. If
-the kernel module is available it will automatically be loaded if you try to
-mount a WIM file. Wimlib has only been tested with the Linux version of FUSE.
-For more information see http://fuse.sourceforge.net/.
-
-The `mkwinpeimg' shell script will look for several other programs depending on
-what options are given to it. Depending on your GNU/Linux distribution, you may
-already have these programs installed, or they may be in the software
-repository. Making an ISO filesystem requires `mkisofs' from `cdrkit'
-(http://www.cdrkit.org). Making a disk image requires `mtools'
-(http://www.gnu.org/software/mtools) and `syslinux' (http://www.syslinux.org).
-Retrieving files from the Windows Automated Installation Kit requires
-`cabextract' (http://www.cabextract.org.uk).
-
-------------------------------------------------------------------------------
-
PORTABILITY
wimlib has mostly been developed and tested on x86_64 (64-bit) GNU/Linux.
It has been tested on x86 (32-bit) GNU/Linux occasionally.
-It can also be compiled and run on FreeBSD.
+wimlib may work on FreeBSD and Mac OS X. However, this is not well tested. If
+you do not have libntfs-3g 2011-4-12 or later available, you must configure
+wimlib with --without-ntfs-3g. On FreeBSD, before mounting a WIM you need to
+load the POSIX message queue module (run `kldload mqueuefs').
-wimlib should work on big endian machines but it has not been tested.
+The code pays attention to endianness, so it should work on big-endian
+architectures, but I've never tested this so do not expect it to work.
There are no plans to port wimlib to Windows since the programming interface on
Windows is very different and Microsoft's imagex.exe is already available.
-------------------------------------------------------------------------------
-
- REFERENCES
+ REFERENCES
The WIM file format is specified in a document that can be found in the
Microsoft Download Center. There is a similar document that specifies the LZX
compression format, and a document that specifies the XPRESS compression format.
-However, some aspects of these formats are poorly documented. Some particularly
-poorly documented parts of the formats have had comments added in various places
-in the library.
-
-lzx-decomp.c, the code to decompress WIM file resources that are compressed
+However, many parts of these formats are poorly documented, and some parts have
+no documentation whatsoever. Some particularly poorly documented parts of the
+formats have had comments added in various places in the library. Please see
+the code and/or ask me if you have any questions about the WIM file format as it
+exists in reality and not as it exists in Microsoft's poorly written
+documentation.
+
+The code in ntfs-apply.c and ntfs-capture.c uses the NTFS-3g library, which is a
+library for reading and writing to NTFS filesystems (the filesystem used by
+recent versions of Windows). See
+http://www.tuxera.com/community/ntfs-3g-download/ for more information.
+
+lzx-decompress.c, the code to decompress WIM file resources that are compressed
using LZX compression, is originally based on code from the cabextract project
-(http://www.cabextract.org.uk).
-
-lzx-comp.c, the code to compress WIM file resources using LZX compression, is
-originally based on code written by Matthew Russotto (www.russotto.net/chm/).
+(http://www.cabextract.org.uk).
-lz.c, the code to find LZ77 matches, is based on code from zlib.
+lzx-compress.c, the code to compress WIM file resources using LZX compression,
+is originally based on code written by Matthew Russotto (www.russotto.net/chm/).
-sha1.c and sha1.h, the code to compute SHA1 message digests of WIM resources or
-of the WIM file itself in the case of integrity checks, are based on code from
-GNU coreutils.
+lz77.c, the code to find LZ77 matches (used for both XPRESS and LZX compression),
+is based on code from zlib.
A very limited number of other free programs can handle some parts of the WIM
-file format. 7-zip is able to extract and create WIMs and files in many other
-archive formats. However, WIMLIB is designed specifically to handle WIM files
-and provides features previously only available in Microsoft's imagex.exe, such
-as the ability to mount WIMs read-write.
-
-------------------------------------------------------------------------------
+file format. 7-zip is able to extract and create WIMs (as well as files in many
+other archive formats). However, wimlib is designed specifically to handle WIM
+files and provides features previously only available in Microsoft's imagex.exe,
+such as the ability to mount WIMs read-write as well as read-only, the ability
+to create LZX or XPRESS compressed WIMs, and the correct handling of security
+descriptors and hard links.
+
+An earlier version of wimlib is being used to deploy Windows 7 from the Ultimate
+Deployment Appliance. For more information see
+http://www.ultimatedeployment.org/.
+
+You can see the documentation about Microsoft's version of the imagex program at
+http://technet.microsoft.com/en-us/library/cc749447(v=ws.10).aspx, so you can
+see how it compares to the version provided by this library.
+
+ GNU/Linux equivalents of WIM format
+
+What's the equivalent way to capture the filesystem of a GNU/Linux operating
+system into an archive file? You have a few options:
+
+SquashFS:
+ SquashFS (http://squashfs.sourceforge.net/) provides a compressed,
+ read-only filesystem for Linux, and it's probably the closest equivalent
+ of the WIM format and better designed. Although you can't mount
+ SquashFS read-write, when wimlib does this for WIM files it's really an
+ illusion since the WIM isn't actually modified until the image is
+ unmounted. Multiple top-level images in SquashFS files are not
+ supported, although nothing stops you from just putting each image in a
+ separate directory.
+
+FSArchiver:
+ FSArchiver (http://www.fsarchiver.org/Main_Page) is not widely used, but
+ it appears to have some features quite similar to the WIM format.
+
+Tar:
+ The well-known tar format can usually capture a UNIX filesystem just
+ fine, and compressing the tar file produces a good compression ratio
+ (better than WIM, especially if using XZ compression), but there is no
+ support for random access, file deduplication, multiple images per
+ archive, or extended attributes.
+
+Zip:
+ Zip shares some features with WIM but is not designed to store entire
+ filesystems.
+
+7z:
+ The 7z format has some nice features but is unfortunately not designed
+ with UNIX in mind.
MORE INFORMATION
See the manual pages for `imagex', the manual pages for the subcommands of
`imagex', and the manual page for `mkwinpeimg'.
-As of version 0.5.0, Wimlib's public API is documented. Doxygen is required to
+As of version 0.5.0, wimlib's public API is documented. Doxygen is required to
build the documentation. To build the documentation, run `configure', then
enter the directory `doc' and run `doxygen'. The HTML documentation will be
created in a directory named `html'.
-------------------------------------------------------------------------------
-
LICENSE
-Wimlib is released under the GNU LGPL version 2.1 or later. The files in the
-`programs' directory are released under the GPL version 3.
+As of version 1.0.0, wimlib is released under the GNU GPL version 3.0 or later.
+This includes the files in the `programs' directory as well as the files in the
+`src' directory.
+
+wimlib is independently developed and does not contain any code, data, or files
+copyrighted by Microsoft. It is not known to be affected by any patents.
+
+By default, wimlib will be linked to the system library "libcrypto", which
+probably will be OpenSSL. Some people believe that GPL code cannot be linked to
+OpenSSL without a linking exception. As far as I know, I cannot officially
+include a linking exception with the license of this library because several
+files could be considered derived works of code copyrighted by others. If you
+believe this to be a problem, configure with --without-libcrypto to avoid
+linking with OpenSSL. There is no difference in functionality--- there will
+just be stand-alone SHA1 message digest code built into the library.
-------------------------------------------------------------------------------
+ DISCLAIMER
- DISCLAIMER
+wimlib is experimental. Use Microsoft's `imagex.exe' if you want to make sure
+your WIM files are made correctly (but beware: Microsoft's version contains some
+bugs).
-Wimlib is experimental. Use Microsoft's `imagex.exe' if you want to make sure
-your WIM files are made correctly. Please submit a bug report (to
-ebiggers3@gmail.com) if you find a bug.
+Please submit a bug report (to ebiggers3@gmail.com) if you find a bug in wimlib.
Some parts of the WIM file format are poorly documented or even completely
-undocumented, so these parts had to be reverse engineered.
+undocumented, so I've just had to do the best I can to read and write WIMs that
+appear to be compatible with Microsoft's software.
git://wimlib.net / wimlib / blobdiff