Initial copy of xz-embedded to sys/contrib/.

The upcoming geom_compress module (a read-only gzip/ulzma translation layer,
similar to what geom_uzip does) will leverage parts of this.
This commit is contained in:
Adrian Chadd 2012-01-01 21:32:25 +00:00
commit 63dab8eed9
23 changed files with 4758 additions and 0 deletions

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Licensing of XZ Embedded
========================
All the files in this package have been written by Lasse Collin
and/or Igor Pavlov. All these files have been put into the
public domain. You can do whatever you want with these files.
As usual, this software is provided "as is", without any warranty.

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XZ Embedded
===========
XZ Embedded is a relatively small, limited implementation of the .xz
file format. Currently only decoding is implemented.
XZ Embedded was written for use in the Linux kernel, but the code can
be easily used in other environments too, including regular userspace
applications.
This README contains information that is useful only when the copy
of XZ Embedded isn't part of the Linux kernel tree. You should also
read linux/Documentation/xz.txt even if you aren't using XZ Embedded
as part of Linux; information in that file is not repeated in this
README.
Compiling the Linux kernel module
The xz_dec module depends on crc32 module, so make sure that you have
it enabled (CONFIG_CRC32).
Building the xz_dec and xz_dec_test modules without support for BCJ
filters:
cd linux/lib/xz
make -C /path/to/kernel/source \
KCPPFLAGS=-I"$(pwd)/../../include" M="$(pwd)" \
CONFIG_XZ_DEC=m CONFIG_XZ_DEC_TEST=m
Building the xz_dec and xz_dec_test modules with support for BCJ
filters:
cd linux/lib/xz
make -C /path/to/kernel/source \
KCPPFLAGS=-I"$(pwd)/../../include" M="$(pwd)" \
CONFIG_XZ_DEC=m CONFIG_XZ_DEC_TEST=m CONFIG_XZ_DEC_BCJ=y \
CONFIG_XZ_DEC_X86=y CONFIG_XZ_DEC_POWERPC=y \
CONFIG_XZ_DEC_IA64=y CONFIG_XZ_DEC_ARM=y \
CONFIG_XZ_DEC_ARMTHUMB=y CONFIG_XZ_DEC_SPARC=y
If you want only one or a few of the BCJ filters, omit the appropriate
variables. CONFIG_XZ_DEC_BCJ=y is always required to build the support
code shared between all BCJ filters.
Most people don't need the xz_dec_test module. You can skip building
it by omitting CONFIG_XZ_DEC_TEST=m from the make command line.
Compiler requirements
XZ Embedded should compile as either GNU-C89 (used in the Linux
kernel) or with any C99 compiler. Getting the code to compile with
non-GNU C89 compiler or a C++ compiler should be quite easy as
long as there is a data type for unsigned 64-bit integer (or the
code is modified not to support large files, which needs some more
care than just using 32-bit integer instead of 64-bit).
If you use GCC, try to use a recent version. For example, on x86-32,
xz_dec_lzma2.c compiled with GCC 3.3.6 is 15-25 % slower than when
compiled with GCC 4.3.3.
Embedding into userspace applications
To embed the XZ decoder, copy the following files into a single
directory in your source code tree:
linux/include/linux/xz.h
linux/lib/xz/xz_crc32.c
linux/lib/xz/xz_dec_lzma2.c
linux/lib/xz/xz_dec_stream.c
linux/lib/xz/xz_lzma2.h
linux/lib/xz/xz_private.h
linux/lib/xz/xz_stream.h
userspace/xz_config.h
Alternatively, xz.h may be placed into a different directory but then
that directory must be in the compiler include path when compiling
the .c files.
Your code should use only the functions declared in xz.h. The rest of
the .h files are meant only for internal use in XZ Embedded.
You may want to modify xz_config.h to be more suitable for your build
environment. Probably you should at least skim through it even if the
default file works as is.
BCJ filter support
If you want support for one or more BCJ filters, you need to copy also
linux/lib/xz/xz_dec_bcj.c into your application, and use appropriate
#defines in xz_config.h or in compiler flags. You don't need these
#defines in the code that just uses XZ Embedded via xz.h, but having
them always #defined doesn't hurt either.
#define Instruction set BCJ filter endianness
XZ_DEC_X86 x86-32 or x86-64 Little endian only
XZ_DEC_POWERPC PowerPC Big endian only
XZ_DEC_IA64 Itanium (IA-64) Big or little endian
XZ_DEC_ARM ARM Little endian only
XZ_DEC_ARMTHUMB ARM-Thumb Little endian only
XZ_DEC_SPARC SPARC Big or little endian
While some architectures are (partially) bi-endian, the endianness
setting doesn't change the endianness of the instructions on all
architectures. That's why Itanium and SPARC filters work for both big
and little endian executables (Itanium has little endian instructions
and SPARC has big endian instructions).
There currently is no filter for little endian PowerPC or big endian
ARM or ARM-Thumb. Implementing filters for them can be considered if
there is a need for such filters in real-world applications.
Notes about shared libraries
If you are including XZ Embedded into a shared library, you very
probably should rename the xz_* functions to prevent symbol
conflicts in case your library is linked against some other library
or application that also has XZ Embedded in it (which may even be
a different version of XZ Embedded). TODO: Provide an easy way
to do this.
Please don't create a shared library of XZ Embedded itself unless
it is fine to rebuild everything depending on that shared library
everytime you upgrade to a newer version of XZ Embedded. There are
no API or ABI stability guarantees between different versions of
XZ Embedded.

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XZ data compression in Linux
============================
Introduction
XZ is a general purpose data compression format with high compression
ratio and relatively fast decompression. The primary compression
algorithm (filter) is LZMA2. Additional filters can be used to improve
compression ratio even further. E.g. Branch/Call/Jump (BCJ) filters
improve compression ratio of executable data.
The XZ decompressor in Linux is called XZ Embedded. It supports
the LZMA2 filter and optionally also BCJ filters. CRC32 is supported
for integrity checking. The home page of XZ Embedded is at
<http://tukaani.org/xz/embedded.html>, where you can find the
latest version and also information about using the code outside
the Linux kernel.
For userspace, XZ Utils provide a zlib-like compression library
and a gzip-like command line tool. XZ Utils can be downloaded from
<http://tukaani.org/xz/>.
XZ related components in the kernel
The xz_dec module provides XZ decompressor with single-call (buffer
to buffer) and multi-call (stateful) APIs. The usage of the xz_dec
module is documented in include/linux/xz.h.
The xz_dec_test module is for testing xz_dec. xz_dec_test is not
useful unless you are hacking the XZ decompressor. xz_dec_test
allocates a char device major dynamically to which one can write
.xz files from userspace. The decompressed output is thrown away.
Keep an eye on dmesg to see diagnostics printed by xz_dec_test.
See the xz_dec_test source code for the details.
For decompressing the kernel image, initramfs, and initrd, there
is a wrapper function in lib/decompress_unxz.c. Its API is the
same as in other decompress_*.c files, which is defined in
include/linux/decompress/generic.h.
scripts/xz_wrap.sh is a wrapper for the xz command line tool found
from XZ Utils. The wrapper sets compression options to values suitable
for compressing the kernel image.
For kernel makefiles, two commands are provided for use with
$(call if_needed). The kernel image should be compressed with
$(call if_needed,xzkern) which will use a BCJ filter and a big LZMA2
dictionary. It will also append a four-byte trailer containing the
uncompressed size of the file, which is needed by the boot code.
Other things should be compressed with $(call if_needed,xzmisc)
which will use no BCJ filter and 1 MiB LZMA2 dictionary.
Notes on compression options
Since the XZ Embedded supports only streams with no integrity check or
CRC32, make sure that you don't use some other integrity check type
when encoding files that are supposed to be decoded by the kernel. With
liblzma, you need to use either LZMA_CHECK_NONE or LZMA_CHECK_CRC32
when encoding. With the xz command line tool, use --check=none or
--check=crc32.
Using CRC32 is strongly recommended unless there is some other layer
which will verify the integrity of the uncompressed data anyway.
Double checking the integrity would probably be waste of CPU cycles.
Note that the headers will always have a CRC32 which will be validated
by the decoder; you can only change the integrity check type (or
disable it) for the actual uncompressed data.
In userspace, LZMA2 is typically used with dictionary sizes of several
megabytes. The decoder needs to have the dictionary in RAM, thus big
dictionaries cannot be used for files that are intended to be decoded
by the kernel. 1 MiB is probably the maximum reasonable dictionary
size for in-kernel use (maybe more is OK for initramfs). The presets
in XZ Utils may not be optimal when creating files for the kernel,
so don't hesitate to use custom settings. Example:
xz --check=crc32 --lzma2=dict=512KiB inputfile
An exception to above dictionary size limitation is when the decoder
is used in single-call mode. Decompressing the kernel itself is an
example of this situation. In single-call mode, the memory usage
doesn't depend on the dictionary size, and it is perfectly fine to
use a big dictionary: for maximum compression, the dictionary should
be at least as big as the uncompressed data itself.
Future plans
Creating a limited XZ encoder may be considered if people think it is
useful. LZMA2 is slower to compress than e.g. Deflate or LZO even at
the fastest settings, so it isn't clear if LZMA2 encoder is wanted
into the kernel.
Support for limited random-access reading is planned for the
decompression code. I don't know if it could have any use in the
kernel, but I know that it would be useful in some embedded projects
outside the Linux kernel.
Conformance to the .xz file format specification
There are a couple of corner cases where things have been simplified
at expense of detecting errors as early as possible. These should not
matter in practice all, since they don't cause security issues. But
it is good to know this if testing the code e.g. with the test files
from XZ Utils.
Reporting bugs
Before reporting a bug, please check that it's not fixed already
at upstream. See <http://tukaani.org/xz/embedded.html> to get the
latest code.
Report bugs to <lasse.collin@tukaani.org> or visit #tukaani on
Freenode and talk to Larhzu. I don't actively read LKML or other
kernel-related mailing lists, so if there's something I should know,
you should email to me personally or use IRC.
Don't bother Igor Pavlov with questions about the XZ implementation
in the kernel or about XZ Utils. While these two implementations
include essential code that is directly based on Igor Pavlov's code,
these implementations aren't maintained nor supported by him.

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/*
* Wrapper for decompressing XZ-compressed kernel, initramfs, and initrd
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#ifndef DECOMPRESS_UNXZ_H
#define DECOMPRESS_UNXZ_H
int unxz(unsigned char *in, int in_size,
int (*fill)(void *dest, unsigned int size),
int (*flush)(void *src, unsigned int size),
unsigned char *out, int *in_used,
void (*error)(char *x));
#endif

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/*
* XZ decompressor
*
* Authors: Lasse Collin <lasse.collin@tukaani.org>
* Igor Pavlov <http://7-zip.org/>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#ifndef XZ_H
#define XZ_H
#ifdef __KERNEL__
# include <linux/stddef.h>
# include <linux/types.h>
#else
# include <stddef.h>
# include <stdint.h>
#endif
#ifdef __cplusplus
extern "C" {
#endif
/* In Linux, this is used to make extern functions static when needed. */
#ifndef XZ_EXTERN
# define XZ_EXTERN extern
#endif
/**
* enum xz_mode - Operation mode
*
* @XZ_SINGLE: Single-call mode. This uses less RAM than
* than multi-call modes, because the LZMA2
* dictionary doesn't need to be allocated as
* part of the decoder state. All required data
* structures are allocated at initialization,
* so xz_dec_run() cannot return XZ_MEM_ERROR.
* @XZ_PREALLOC: Multi-call mode with preallocated LZMA2
* dictionary buffer. All data structures are
* allocated at initialization, so xz_dec_run()
* cannot return XZ_MEM_ERROR.
* @XZ_DYNALLOC: Multi-call mode. The LZMA2 dictionary is
* allocated once the required size has been
* parsed from the stream headers. If the
* allocation fails, xz_dec_run() will return
* XZ_MEM_ERROR.
*
* It is possible to enable support only for a subset of the above
* modes at compile time by defining XZ_DEC_SINGLE, XZ_DEC_PREALLOC,
* or XZ_DEC_DYNALLOC. The xz_dec kernel module is always compiled
* with support for all operation modes, but the preboot code may
* be built with fewer features to minimize code size.
*/
enum xz_mode {
XZ_SINGLE,
XZ_PREALLOC,
XZ_DYNALLOC
};
/**
* enum xz_ret - Return codes
* @XZ_OK: Everything is OK so far. More input or more
* output space is required to continue. This
* return code is possible only in multi-call mode
* (XZ_PREALLOC or XZ_DYNALLOC).
* @XZ_STREAM_END: Operation finished successfully.
* @XZ_UNSUPPORTED_CHECK: Integrity check type is not supported. Decoding
* is still possible in multi-call mode by simply
* calling xz_dec_run() again.
* Note that this return value is used only if
* XZ_DEC_ANY_CHECK was defined at build time,
* which is not used in the kernel. Unsupported
* check types return XZ_OPTIONS_ERROR if
* XZ_DEC_ANY_CHECK was not defined at build time.
* @XZ_MEM_ERROR: Allocating memory failed. This return code is
* possible only if the decoder was initialized
* with XZ_DYNALLOC. The amount of memory that was
* tried to be allocated was no more than the
* dict_max argument given to xz_dec_init().
* @XZ_MEMLIMIT_ERROR: A bigger LZMA2 dictionary would be needed than
* allowed by the dict_max argument given to
* xz_dec_init(). This return value is possible
* only in multi-call mode (XZ_PREALLOC or
* XZ_DYNALLOC); the single-call mode (XZ_SINGLE)
* ignores the dict_max argument.
* @XZ_FORMAT_ERROR: File format was not recognized (wrong magic
* bytes).
* @XZ_OPTIONS_ERROR: This implementation doesn't support the requested
* compression options. In the decoder this means
* that the header CRC32 matches, but the header
* itself specifies something that we don't support.
* @XZ_DATA_ERROR: Compressed data is corrupt.
* @XZ_BUF_ERROR: Cannot make any progress. Details are slightly
* different between multi-call and single-call
* mode; more information below.
*
* In multi-call mode, XZ_BUF_ERROR is returned when two consecutive calls
* to XZ code cannot consume any input and cannot produce any new output.
* This happens when there is no new input available, or the output buffer
* is full while at least one output byte is still pending. Assuming your
* code is not buggy, you can get this error only when decoding a compressed
* stream that is truncated or otherwise corrupt.
*
* In single-call mode, XZ_BUF_ERROR is returned only when the output buffer
* is too small or the compressed input is corrupt in a way that makes the
* decoder produce more output than the caller expected. When it is
* (relatively) clear that the compressed input is truncated, XZ_DATA_ERROR
* is used instead of XZ_BUF_ERROR.
*/
enum xz_ret {
XZ_OK,
XZ_STREAM_END,
XZ_UNSUPPORTED_CHECK,
XZ_MEM_ERROR,
XZ_MEMLIMIT_ERROR,
XZ_FORMAT_ERROR,
XZ_OPTIONS_ERROR,
XZ_DATA_ERROR,
XZ_BUF_ERROR
};
/**
* struct xz_buf - Passing input and output buffers to XZ code
* @in: Beginning of the input buffer. This may be NULL if and only
* if in_pos is equal to in_size.
* @in_pos: Current position in the input buffer. This must not exceed
* in_size.
* @in_size: Size of the input buffer
* @out: Beginning of the output buffer. This may be NULL if and only
* if out_pos is equal to out_size.
* @out_pos: Current position in the output buffer. This must not exceed
* out_size.
* @out_size: Size of the output buffer
*
* Only the contents of the output buffer from out[out_pos] onward, and
* the variables in_pos and out_pos are modified by the XZ code.
*/
struct xz_buf {
const uint8_t *in;
size_t in_pos;
size_t in_size;
uint8_t *out;
size_t out_pos;
size_t out_size;
};
/**
* struct xz_dec - Opaque type to hold the XZ decoder state
*/
struct xz_dec;
/**
* xz_dec_init() - Allocate and initialize a XZ decoder state
* @mode: Operation mode
* @dict_max: Maximum size of the LZMA2 dictionary (history buffer) for
* multi-call decoding. This is ignored in single-call mode
* (mode == XZ_SINGLE). LZMA2 dictionary is always 2^n bytes
* or 2^n + 2^(n-1) bytes (the latter sizes are less common
* in practice), so other values for dict_max don't make sense.
* In the kernel, dictionary sizes of 64 KiB, 128 KiB, 256 KiB,
* 512 KiB, and 1 MiB are probably the only reasonable values,
* except for kernel and initramfs images where a bigger
* dictionary can be fine and useful.
*
* Single-call mode (XZ_SINGLE): xz_dec_run() decodes the whole stream at
* once. The caller must provide enough output space or the decoding will
* fail. The output space is used as the dictionary buffer, which is why
* there is no need to allocate the dictionary as part of the decoder's
* internal state.
*
* Because the output buffer is used as the workspace, streams encoded using
* a big dictionary are not a problem in single-call mode. It is enough that
* the output buffer is big enough to hold the actual uncompressed data; it
* can be smaller than the dictionary size stored in the stream headers.
*
* Multi-call mode with preallocated dictionary (XZ_PREALLOC): dict_max bytes
* of memory is preallocated for the LZMA2 dictionary. This way there is no
* risk that xz_dec_run() could run out of memory, since xz_dec_run() will
* never allocate any memory. Instead, if the preallocated dictionary is too
* small for decoding the given input stream, xz_dec_run() will return
* XZ_MEMLIMIT_ERROR. Thus, it is important to know what kind of data will be
* decoded to avoid allocating excessive amount of memory for the dictionary.
*
* Multi-call mode with dynamically allocated dictionary (XZ_DYNALLOC):
* dict_max specifies the maximum allowed dictionary size that xz_dec_run()
* may allocate once it has parsed the dictionary size from the stream
* headers. This way excessive allocations can be avoided while still
* limiting the maximum memory usage to a sane value to prevent running the
* system out of memory when decompressing streams from untrusted sources.
*
* On success, xz_dec_init() returns a pointer to struct xz_dec, which is
* ready to be used with xz_dec_run(). If memory allocation fails,
* xz_dec_init() returns NULL.
*/
XZ_EXTERN struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max);
/**
* xz_dec_run() - Run the XZ decoder
* @s: Decoder state allocated using xz_dec_init()
* @b: Input and output buffers
*
* The possible return values depend on build options and operation mode.
* See enum xz_ret for details.
*
* Note that if an error occurs in single-call mode (return value is not
* XZ_STREAM_END), b->in_pos and b->out_pos are not modified and the
* contents of the output buffer from b->out[b->out_pos] onward are
* undefined. This is true even after XZ_BUF_ERROR, because with some filter
* chains, there may be a second pass over the output buffer, and this pass
* cannot be properly done if the output buffer is truncated. Thus, you
* cannot give the single-call decoder a too small buffer and then expect to
* get that amount valid data from the beginning of the stream. You must use
* the multi-call decoder if you don't want to uncompress the whole stream.
*/
XZ_EXTERN enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b);
/**
* xz_dec_reset() - Reset an already allocated decoder state
* @s: Decoder state allocated using xz_dec_init()
*
* This function can be used to reset the multi-call decoder state without
* freeing and reallocating memory with xz_dec_end() and xz_dec_init().
*
* In single-call mode, xz_dec_reset() is always called in the beginning of
* xz_dec_run(). Thus, explicit call to xz_dec_reset() is useful only in
* multi-call mode.
*/
XZ_EXTERN void xz_dec_reset(struct xz_dec *s);
/**
* xz_dec_end() - Free the memory allocated for the decoder state
* @s: Decoder state allocated using xz_dec_init(). If s is NULL,
* this function does nothing.
*/
XZ_EXTERN void xz_dec_end(struct xz_dec *s);
/*
* Standalone build (userspace build or in-kernel build for boot time use)
* needs a CRC32 implementation. For normal in-kernel use, kernel's own
* CRC32 module is used instead, and users of this module don't need to
* care about the functions below.
*/
#ifndef XZ_INTERNAL_CRC32
# ifdef __KERNEL__
# define XZ_INTERNAL_CRC32 0
# else
# define XZ_INTERNAL_CRC32 1
# endif
#endif
#if XZ_INTERNAL_CRC32
/*
* This must be called before any other xz_* function to initialize
* the CRC32 lookup table.
*/
XZ_EXTERN void xz_crc32_init(void);
/*
* Update CRC32 value using the polynomial from IEEE-802.3. To start a new
* calculation, the third argument must be zero. To continue the calculation,
* the previously returned value is passed as the third argument.
*/
XZ_EXTERN uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc);
#endif
#ifdef __cplusplus
}
#endif
#endif

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/*
* Wrapper for decompressing XZ-compressed kernel, initramfs, and initrd
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
/*
* Important notes about in-place decompression
*
* At least on x86, the kernel is decompressed in place: the compressed data
* is placed to the end of the output buffer, and the decompressor overwrites
* most of the compressed data. There must be enough safety margin to
* guarantee that the write position is always behind the read position.
*
* The safety margin for XZ with LZMA2 or BCJ+LZMA2 is calculated below.
* Note that the margin with XZ is bigger than with Deflate (gzip)!
*
* The worst case for in-place decompression is that the beginning of
* the file is compressed extremely well, and the rest of the file is
* uncompressible. Thus, we must look for worst-case expansion when the
* compressor is encoding uncompressible data.
*
* The structure of the .xz file in case of a compresed kernel is as follows.
* Sizes (as bytes) of the fields are in parenthesis.
*
* Stream Header (12)
* Block Header:
* Block Header (8-12)
* Compressed Data (N)
* Block Padding (0-3)
* CRC32 (4)
* Index (8-20)
* Stream Footer (12)
*
* Normally there is exactly one Block, but let's assume that there are
* 2-4 Blocks just in case. Because Stream Header and also Block Header
* of the first Block don't make the decompressor produce any uncompressed
* data, we can ignore them from our calculations. Block Headers of possible
* additional Blocks have to be taken into account still. With these
* assumptions, it is safe to assume that the total header overhead is
* less than 128 bytes.
*
* Compressed Data contains LZMA2 or BCJ+LZMA2 encoded data. Since BCJ
* doesn't change the size of the data, it is enough to calculate the
* safety margin for LZMA2.
*
* LZMA2 stores the data in chunks. Each chunk has a header whose size is
* a maximum of 6 bytes, but to get round 2^n numbers, let's assume that
* the maximum chunk header size is 8 bytes. After the chunk header, there
* may be up to 64 KiB of actual payload in the chunk. Often the payload is
* quite a bit smaller though; to be safe, let's assume that an average
* chunk has only 32 KiB of payload.
*
* The maximum uncompressed size of the payload is 2 MiB. The minimum
* uncompressed size of the payload is in practice never less than the
* payload size itself. The LZMA2 format would allow uncompressed size
* to be less than the payload size, but no sane compressor creates such
* files. LZMA2 supports storing uncompressible data in uncompressed form,
* so there's never a need to create payloads whose uncompressed size is
* smaller than the compressed size.
*
* The assumption, that the uncompressed size of the payload is never
* smaller than the payload itself, is valid only when talking about
* the payload as a whole. It is possible that the payload has parts where
* the decompressor consumes more input than it produces output. Calculating
* the worst case for this would be tricky. Instead of trying to do that,
* let's simply make sure that the decompressor never overwrites any bytes
* of the payload which it is currently reading.
*
* Now we have enough information to calculate the safety margin. We need
* - 128 bytes for the .xz file format headers;
* - 8 bytes per every 32 KiB of uncompressed size (one LZMA2 chunk header
* per chunk, each chunk having average payload size of 32 KiB); and
* - 64 KiB (biggest possible LZMA2 chunk payload size) to make sure that
* the decompressor never overwrites anything from the LZMA2 chunk
* payload it is currently reading.
*
* We get the following formula:
*
* safety_margin = 128 + uncompressed_size * 8 / 32768 + 65536
* = 128 + (uncompressed_size >> 12) + 65536
*
* For comparision, according to arch/x86/boot/compressed/misc.c, the
* equivalent formula for Deflate is this:
*
* safety_margin = 18 + (uncompressed_size >> 12) + 32768
*
* Thus, when updating Deflate-only in-place kernel decompressor to
* support XZ, the fixed overhead has to be increased from 18+32768 bytes
* to 128+65536 bytes.
*/
/*
* STATIC is defined to "static" if we are being built for kernel
* decompression (pre-boot code). <linux/decompress/mm.h> will define
* STATIC to empty if it wasn't already defined. Since we will need to
* know later if we are being used for kernel decompression, we define
* XZ_PREBOOT here.
*/
#ifdef STATIC
# define XZ_PREBOOT
#endif
#ifdef __KERNEL__
# include <linux/decompress/mm.h>
#endif
#define XZ_EXTERN STATIC
#ifndef XZ_PREBOOT
# include <linux/slab.h>
# include <linux/xz.h>
#else
/*
* Use the internal CRC32 code instead of kernel's CRC32 module, which
* is not available in early phase of booting.
*/
#define XZ_INTERNAL_CRC32 1
/*
* For boot time use, we enable only the BCJ filter of the current
* architecture or none if no BCJ filter is available for the architecture.
*/
#ifdef CONFIG_X86
# define XZ_DEC_X86
#endif
#ifdef CONFIG_PPC
# define XZ_DEC_POWERPC
#endif
#ifdef CONFIG_ARM
# define XZ_DEC_ARM
#endif
#ifdef CONFIG_IA64
# define XZ_DEC_IA64
#endif
#ifdef CONFIG_SPARC
# define XZ_DEC_SPARC
#endif
/*
* This will get the basic headers so that memeq() and others
* can be defined.
*/
#include "xz/xz_private.h"
/*
* Replace the normal allocation functions with the versions from
* <linux/decompress/mm.h>. vfree() needs to support vfree(NULL)
* when XZ_DYNALLOC is used, but the pre-boot free() doesn't support it.
* Workaround it here because the other decompressors don't need it.
*/
#undef kmalloc
#undef kfree
#undef vmalloc
#undef vfree
#define kmalloc(size, flags) malloc(size)
#define kfree(ptr) free(ptr)
#define vmalloc(size) malloc(size)
#define vfree(ptr) do { if (ptr != NULL) free(ptr); } while (0)
/*
* FIXME: Not all basic memory functions are provided in architecture-specific
* files (yet). We define our own versions here for now, but this should be
* only a temporary solution.
*
* memeq and memzero are not used much and any remotely sane implementation
* is fast enough. memcpy/memmove speed matters in multi-call mode, but
* the kernel image is decompressed in single-call mode, in which only
* memcpy speed can matter and only if there is a lot of uncompressible data
* (LZMA2 stores uncompressible chunks in uncompressed form). Thus, the
* functions below should just be kept small; it's probably not worth
* optimizing for speed.
*/
#ifndef memeq
static bool memeq(const void *a, const void *b, size_t size)
{
const uint8_t *x = a;
const uint8_t *y = b;
size_t i;
for (i = 0; i < size; ++i)
if (x[i] != y[i])
return false;
return true;
}
#endif
#ifndef memzero
static void memzero(void *buf, size_t size)
{
uint8_t *b = buf;
uint8_t *e = b + size;
while (b != e)
*b++ = '\0';
}
#endif
#ifndef memmove
/* Not static to avoid a conflict with the prototype in the Linux headers. */
void *memmove(void *dest, const void *src, size_t size)
{
uint8_t *d = dest;
const uint8_t *s = src;
size_t i;
if (d < s) {
for (i = 0; i < size; ++i)
d[i] = s[i];
} else if (d > s) {
i = size;
while (i-- > 0)
d[i] = s[i];
}
return dest;
}
#endif
/*
* Since we need memmove anyway, would use it as memcpy too.
* Commented out for now to avoid breaking things.
*/
/*
#ifndef memcpy
# define memcpy memmove
#endif
*/
#include "xz/xz_crc32.c"
#include "xz/xz_dec_stream.c"
#include "xz/xz_dec_lzma2.c"
#include "xz/xz_dec_bcj.c"
#endif /* XZ_PREBOOT */
/* Size of the input and output buffers in multi-call mode */
#define XZ_IOBUF_SIZE 4096
/*
* This function implements the API defined in <linux/decompress/generic.h>.
*
* This wrapper will automatically choose single-call or multi-call mode
* of the native XZ decoder API. The single-call mode can be used only when
* both input and output buffers are available as a single chunk, i.e. when
* fill() and flush() won't be used.
*/
STATIC int INIT unxz(unsigned char *in, int in_size,
int (*fill)(void *dest, unsigned int size),
int (*flush)(void *src, unsigned int size),
unsigned char *out, int *in_used,
void (*error)(char *x))
{
struct xz_buf b;
struct xz_dec *s;
enum xz_ret ret;
bool must_free_in = false;
#if XZ_INTERNAL_CRC32
xz_crc32_init();
#endif
if (in_used != NULL)
*in_used = 0;
if (fill == NULL && flush == NULL)
s = xz_dec_init(XZ_SINGLE, 0);
else
s = xz_dec_init(XZ_DYNALLOC, (uint32_t)-1);
if (s == NULL)
goto error_alloc_state;
if (flush == NULL) {
b.out = out;
b.out_size = (size_t)-1;
} else {
b.out_size = XZ_IOBUF_SIZE;
b.out = malloc(XZ_IOBUF_SIZE);
if (b.out == NULL)
goto error_alloc_out;
}
if (in == NULL) {
must_free_in = true;
in = malloc(XZ_IOBUF_SIZE);
if (in == NULL)
goto error_alloc_in;
}
b.in = in;
b.in_pos = 0;
b.in_size = in_size;
b.out_pos = 0;
if (fill == NULL && flush == NULL) {
ret = xz_dec_run(s, &b);
} else {
do {
if (b.in_pos == b.in_size && fill != NULL) {
if (in_used != NULL)
*in_used += b.in_pos;
b.in_pos = 0;
in_size = fill(in, XZ_IOBUF_SIZE);
if (in_size < 0) {
/*
* This isn't an optimal error code
* but it probably isn't worth making
* a new one either.
*/
ret = XZ_BUF_ERROR;
break;
}
b.in_size = in_size;
}
ret = xz_dec_run(s, &b);
if (flush != NULL && (b.out_pos == b.out_size
|| (ret != XZ_OK && b.out_pos > 0))) {
/*
* Setting ret here may hide an error
* returned by xz_dec_run(), but probably
* it's not too bad.
*/
if (flush(b.out, b.out_pos) != (int)b.out_pos)
ret = XZ_BUF_ERROR;
b.out_pos = 0;
}
} while (ret == XZ_OK);
if (must_free_in)
free(in);
if (flush != NULL)
free(b.out);
}
if (in_used != NULL)
*in_used += b.in_pos;
xz_dec_end(s);
switch (ret) {
case XZ_STREAM_END:
return 0;
case XZ_MEM_ERROR:
/* This can occur only in multi-call mode. */
error("XZ decompressor ran out of memory");
break;
case XZ_FORMAT_ERROR:
error("Input is not in the XZ format (wrong magic bytes)");
break;
case XZ_OPTIONS_ERROR:
error("Input was encoded with settings that are not "
"supported by this XZ decoder");
break;
case XZ_DATA_ERROR:
case XZ_BUF_ERROR:
error("XZ-compressed data is corrupt");
break;
default:
error("Bug in the XZ decompressor");
break;
}
return -1;
error_alloc_in:
if (flush != NULL)
free(b.out);
error_alloc_out:
xz_dec_end(s);
error_alloc_state:
error("XZ decompressor ran out of memory");
return -1;
}
/*
* This macro is used by architecture-specific files to decompress
* the kernel image.
*/
#define decompress unxz

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@ -0,0 +1,59 @@
config XZ_DEC
tristate "XZ decompression support"
select CRC32
help
LZMA2 compression algorithm and BCJ filters are supported using
the .xz file format as the container. For integrity checking,
CRC32 is supported. See Documentation/xz.txt for more information.
config XZ_DEC_X86
bool "x86 BCJ filter decoder" if EXPERT
default y
depends on XZ_DEC
select XZ_DEC_BCJ
config XZ_DEC_POWERPC
bool "PowerPC BCJ filter decoder" if EXPERT
default y
depends on XZ_DEC
select XZ_DEC_BCJ
config XZ_DEC_IA64
bool "IA-64 BCJ filter decoder" if EXPERT
default y
depends on XZ_DEC
select XZ_DEC_BCJ
config XZ_DEC_ARM
bool "ARM BCJ filter decoder" if EXPERT
default y
depends on XZ_DEC
select XZ_DEC_BCJ
config XZ_DEC_ARMTHUMB
bool "ARM-Thumb BCJ filter decoder" if EXPERT
default y
depends on XZ_DEC
select XZ_DEC_BCJ
config XZ_DEC_SPARC
bool "SPARC BCJ filter decoder" if EXPERT
default y
depends on XZ_DEC
select XZ_DEC_BCJ
config XZ_DEC_BCJ
bool
default n
config XZ_DEC_TEST
tristate "XZ decompressor tester"
default n
depends on XZ_DEC
help
This allows passing .xz files to the in-kernel XZ decoder via
a character special file. It calculates CRC32 of the decompressed
data and writes diagnostics to the system log.
Unless you are developing the XZ decoder, you don't need this
and should say N.

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@ -0,0 +1,5 @@
obj-$(CONFIG_XZ_DEC) += xz_dec.o
xz_dec-y := xz_dec_syms.o xz_dec_stream.o xz_dec_lzma2.o
xz_dec-$(CONFIG_XZ_DEC_BCJ) += xz_dec_bcj.o
obj-$(CONFIG_XZ_DEC_TEST) += xz_dec_test.o

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@ -0,0 +1,59 @@
/*
* CRC32 using the polynomial from IEEE-802.3
*
* Authors: Lasse Collin <lasse.collin@tukaani.org>
* Igor Pavlov <http://7-zip.org/>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
/*
* This is not the fastest implementation, but it is pretty compact.
* The fastest versions of xz_crc32() on modern CPUs without hardware
* accelerated CRC instruction are 3-5 times as fast as this version,
* but they are bigger and use more memory for the lookup table.
*/
#include "xz_private.h"
/*
* STATIC_RW_DATA is used in the pre-boot environment on some architectures.
* See <linux/decompress/mm.h> for details.
*/
#ifndef STATIC_RW_DATA
# define STATIC_RW_DATA static
#endif
STATIC_RW_DATA uint32_t xz_crc32_table[256];
XZ_EXTERN void xz_crc32_init(void)
{
const uint32_t poly = 0xEDB88320;
uint32_t i;
uint32_t j;
uint32_t r;
for (i = 0; i < 256; ++i) {
r = i;
for (j = 0; j < 8; ++j)
r = (r >> 1) ^ (poly & ~((r & 1) - 1));
xz_crc32_table[i] = r;
}
return;
}
XZ_EXTERN uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc)
{
crc = ~crc;
while (size != 0) {
crc = xz_crc32_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
--size;
}
return ~crc;
}

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@ -0,0 +1,574 @@
/*
* Branch/Call/Jump (BCJ) filter decoders
*
* Authors: Lasse Collin <lasse.collin@tukaani.org>
* Igor Pavlov <http://7-zip.org/>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#include "xz_private.h"
/*
* The rest of the file is inside this ifdef. It makes things a little more
* convenient when building without support for any BCJ filters.
*/
#ifdef XZ_DEC_BCJ
struct xz_dec_bcj {
/* Type of the BCJ filter being used */
enum {
BCJ_X86 = 4, /* x86 or x86-64 */
BCJ_POWERPC = 5, /* Big endian only */
BCJ_IA64 = 6, /* Big or little endian */
BCJ_ARM = 7, /* Little endian only */
BCJ_ARMTHUMB = 8, /* Little endian only */
BCJ_SPARC = 9 /* Big or little endian */
} type;
/*
* Return value of the next filter in the chain. We need to preserve
* this information across calls, because we must not call the next
* filter anymore once it has returned XZ_STREAM_END.
*/
enum xz_ret ret;
/* True if we are operating in single-call mode. */
bool single_call;
/*
* Absolute position relative to the beginning of the uncompressed
* data (in a single .xz Block). We care only about the lowest 32
* bits so this doesn't need to be uint64_t even with big files.
*/
uint32_t pos;
/* x86 filter state */
uint32_t x86_prev_mask;
/* Temporary space to hold the variables from struct xz_buf */
uint8_t *out;
size_t out_pos;
size_t out_size;
struct {
/* Amount of already filtered data in the beginning of buf */
size_t filtered;
/* Total amount of data currently stored in buf */
size_t size;
/*
* Buffer to hold a mix of filtered and unfiltered data. This
* needs to be big enough to hold Alignment + 2 * Look-ahead:
*
* Type Alignment Look-ahead
* x86 1 4
* PowerPC 4 0
* IA-64 16 0
* ARM 4 0
* ARM-Thumb 2 2
* SPARC 4 0
*/
uint8_t buf[16];
} temp;
};
#ifdef XZ_DEC_X86
/*
* This is used to test the most significant byte of a memory address
* in an x86 instruction.
*/
static inline int bcj_x86_test_msbyte(uint8_t b)
{
return b == 0x00 || b == 0xFF;
}
static size_t bcj_x86(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
{
static const bool mask_to_allowed_status[8]
= { true, true, true, false, true, false, false, false };
static const uint8_t mask_to_bit_num[8] = { 0, 1, 2, 2, 3, 3, 3, 3 };
size_t i;
size_t prev_pos = (size_t)-1;
uint32_t prev_mask = s->x86_prev_mask;
uint32_t src;
uint32_t dest;
uint32_t j;
uint8_t b;
if (size <= 4)
return 0;
size -= 4;
for (i = 0; i < size; ++i) {
if ((buf[i] & 0xFE) != 0xE8)
continue;
prev_pos = i - prev_pos;
if (prev_pos > 3) {
prev_mask = 0;
} else {
prev_mask = (prev_mask << (prev_pos - 1)) & 7;
if (prev_mask != 0) {
b = buf[i + 4 - mask_to_bit_num[prev_mask]];
if (!mask_to_allowed_status[prev_mask]
|| bcj_x86_test_msbyte(b)) {
prev_pos = i;
prev_mask = (prev_mask << 1) | 1;
continue;
}
}
}
prev_pos = i;
if (bcj_x86_test_msbyte(buf[i + 4])) {
src = get_unaligned_le32(buf + i + 1);
while (true) {
dest = src - (s->pos + (uint32_t)i + 5);
if (prev_mask == 0)
break;
j = mask_to_bit_num[prev_mask] * 8;
b = (uint8_t)(dest >> (24 - j));
if (!bcj_x86_test_msbyte(b))
break;
src = dest ^ (((uint32_t)1 << (32 - j)) - 1);
}
dest &= 0x01FFFFFF;
dest |= (uint32_t)0 - (dest & 0x01000000);
put_unaligned_le32(dest, buf + i + 1);
i += 4;
} else {
prev_mask = (prev_mask << 1) | 1;
}
}
prev_pos = i - prev_pos;
s->x86_prev_mask = prev_pos > 3 ? 0 : prev_mask << (prev_pos - 1);
return i;
}
#endif
#ifdef XZ_DEC_POWERPC
static size_t bcj_powerpc(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
{
size_t i;
uint32_t instr;
for (i = 0; i + 4 <= size; i += 4) {
instr = get_unaligned_be32(buf + i);
if ((instr & 0xFC000003) == 0x48000001) {
instr &= 0x03FFFFFC;
instr -= s->pos + (uint32_t)i;
instr &= 0x03FFFFFC;
instr |= 0x48000001;
put_unaligned_be32(instr, buf + i);
}
}
return i;
}
#endif
#ifdef XZ_DEC_IA64
static size_t bcj_ia64(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
{
static const uint8_t branch_table[32] = {
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
4, 4, 6, 6, 0, 0, 7, 7,
4, 4, 0, 0, 4, 4, 0, 0
};
/*
* The local variables take a little bit stack space, but it's less
* than what LZMA2 decoder takes, so it doesn't make sense to reduce
* stack usage here without doing that for the LZMA2 decoder too.
*/
/* Loop counters */
size_t i;
size_t j;
/* Instruction slot (0, 1, or 2) in the 128-bit instruction word */
uint32_t slot;
/* Bitwise offset of the instruction indicated by slot */
uint32_t bit_pos;
/* bit_pos split into byte and bit parts */
uint32_t byte_pos;
uint32_t bit_res;
/* Address part of an instruction */
uint32_t addr;
/* Mask used to detect which instructions to convert */
uint32_t mask;
/* 41-bit instruction stored somewhere in the lowest 48 bits */
uint64_t instr;
/* Instruction normalized with bit_res for easier manipulation */
uint64_t norm;
for (i = 0; i + 16 <= size; i += 16) {
mask = branch_table[buf[i] & 0x1F];
for (slot = 0, bit_pos = 5; slot < 3; ++slot, bit_pos += 41) {
if (((mask >> slot) & 1) == 0)
continue;
byte_pos = bit_pos >> 3;
bit_res = bit_pos & 7;
instr = 0;
for (j = 0; j < 6; ++j)
instr |= (uint64_t)(buf[i + j + byte_pos])
<< (8 * j);
norm = instr >> bit_res;
if (((norm >> 37) & 0x0F) == 0x05
&& ((norm >> 9) & 0x07) == 0) {
addr = (norm >> 13) & 0x0FFFFF;
addr |= ((uint32_t)(norm >> 36) & 1) << 20;
addr <<= 4;
addr -= s->pos + (uint32_t)i;
addr >>= 4;
norm &= ~((uint64_t)0x8FFFFF << 13);
norm |= (uint64_t)(addr & 0x0FFFFF) << 13;
norm |= (uint64_t)(addr & 0x100000)
<< (36 - 20);
instr &= (1 << bit_res) - 1;
instr |= norm << bit_res;
for (j = 0; j < 6; j++)
buf[i + j + byte_pos]
= (uint8_t)(instr >> (8 * j));
}
}
}
return i;
}
#endif
#ifdef XZ_DEC_ARM
static size_t bcj_arm(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
{
size_t i;
uint32_t addr;
for (i = 0; i + 4 <= size; i += 4) {
if (buf[i + 3] == 0xEB) {
addr = (uint32_t)buf[i] | ((uint32_t)buf[i + 1] << 8)
| ((uint32_t)buf[i + 2] << 16);
addr <<= 2;
addr -= s->pos + (uint32_t)i + 8;
addr >>= 2;
buf[i] = (uint8_t)addr;
buf[i + 1] = (uint8_t)(addr >> 8);
buf[i + 2] = (uint8_t)(addr >> 16);
}
}
return i;
}
#endif
#ifdef XZ_DEC_ARMTHUMB
static size_t bcj_armthumb(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
{
size_t i;
uint32_t addr;
for (i = 0; i + 4 <= size; i += 2) {
if ((buf[i + 1] & 0xF8) == 0xF0
&& (buf[i + 3] & 0xF8) == 0xF8) {
addr = (((uint32_t)buf[i + 1] & 0x07) << 19)
| ((uint32_t)buf[i] << 11)
| (((uint32_t)buf[i + 3] & 0x07) << 8)
| (uint32_t)buf[i + 2];
addr <<= 1;
addr -= s->pos + (uint32_t)i + 4;
addr >>= 1;
buf[i + 1] = (uint8_t)(0xF0 | ((addr >> 19) & 0x07));
buf[i] = (uint8_t)(addr >> 11);
buf[i + 3] = (uint8_t)(0xF8 | ((addr >> 8) & 0x07));
buf[i + 2] = (uint8_t)addr;
i += 2;
}
}
return i;
}
#endif
#ifdef XZ_DEC_SPARC
static size_t bcj_sparc(struct xz_dec_bcj *s, uint8_t *buf, size_t size)
{
size_t i;
uint32_t instr;
for (i = 0; i + 4 <= size; i += 4) {
instr = get_unaligned_be32(buf + i);
if ((instr >> 22) == 0x100 || (instr >> 22) == 0x1FF) {
instr <<= 2;
instr -= s->pos + (uint32_t)i;
instr >>= 2;
instr = ((uint32_t)0x40000000 - (instr & 0x400000))
| 0x40000000 | (instr & 0x3FFFFF);
put_unaligned_be32(instr, buf + i);
}
}
return i;
}
#endif
/*
* Apply the selected BCJ filter. Update *pos and s->pos to match the amount
* of data that got filtered.
*
* NOTE: This is implemented as a switch statement to avoid using function
* pointers, which could be problematic in the kernel boot code, which must
* avoid pointers to static data (at least on x86).
*/
static void bcj_apply(struct xz_dec_bcj *s,
uint8_t *buf, size_t *pos, size_t size)
{
size_t filtered;
buf += *pos;
size -= *pos;
switch (s->type) {
#ifdef XZ_DEC_X86
case BCJ_X86:
filtered = bcj_x86(s, buf, size);
break;
#endif
#ifdef XZ_DEC_POWERPC
case BCJ_POWERPC:
filtered = bcj_powerpc(s, buf, size);
break;
#endif
#ifdef XZ_DEC_IA64
case BCJ_IA64:
filtered = bcj_ia64(s, buf, size);
break;
#endif
#ifdef XZ_DEC_ARM
case BCJ_ARM:
filtered = bcj_arm(s, buf, size);
break;
#endif
#ifdef XZ_DEC_ARMTHUMB
case BCJ_ARMTHUMB:
filtered = bcj_armthumb(s, buf, size);
break;
#endif
#ifdef XZ_DEC_SPARC
case BCJ_SPARC:
filtered = bcj_sparc(s, buf, size);
break;
#endif
default:
/* Never reached but silence compiler warnings. */
filtered = 0;
break;
}
*pos += filtered;
s->pos += filtered;
}
/*
* Flush pending filtered data from temp to the output buffer.
* Move the remaining mixture of possibly filtered and unfiltered
* data to the beginning of temp.
*/
static void bcj_flush(struct xz_dec_bcj *s, struct xz_buf *b)
{
size_t copy_size;
copy_size = min_t(size_t, s->temp.filtered, b->out_size - b->out_pos);
memcpy(b->out + b->out_pos, s->temp.buf, copy_size);
b->out_pos += copy_size;
s->temp.filtered -= copy_size;
s->temp.size -= copy_size;
memmove(s->temp.buf, s->temp.buf + copy_size, s->temp.size);
}
/*
* The BCJ filter functions are primitive in sense that they process the
* data in chunks of 1-16 bytes. To hide this issue, this function does
* some buffering.
*/
XZ_EXTERN enum xz_ret xz_dec_bcj_run(struct xz_dec_bcj *s,
struct xz_dec_lzma2 *lzma2,
struct xz_buf *b)
{
size_t out_start;
/*
* Flush pending already filtered data to the output buffer. Return
* immediatelly if we couldn't flush everything, or if the next
* filter in the chain had already returned XZ_STREAM_END.
*/
if (s->temp.filtered > 0) {
bcj_flush(s, b);
if (s->temp.filtered > 0)
return XZ_OK;
if (s->ret == XZ_STREAM_END)
return XZ_STREAM_END;
}
/*
* If we have more output space than what is currently pending in
* temp, copy the unfiltered data from temp to the output buffer
* and try to fill the output buffer by decoding more data from the
* next filter in the chain. Apply the BCJ filter on the new data
* in the output buffer. If everything cannot be filtered, copy it
* to temp and rewind the output buffer position accordingly.
*
* This needs to be always run when temp.size == 0 to handle a special
* case where the output buffer is full and the next filter has no
* more output coming but hasn't returned XZ_STREAM_END yet.
*/
if (s->temp.size < b->out_size - b->out_pos || s->temp.size == 0) {
out_start = b->out_pos;
memcpy(b->out + b->out_pos, s->temp.buf, s->temp.size);
b->out_pos += s->temp.size;
s->ret = xz_dec_lzma2_run(lzma2, b);
if (s->ret != XZ_STREAM_END
&& (s->ret != XZ_OK || s->single_call))
return s->ret;
bcj_apply(s, b->out, &out_start, b->out_pos);
/*
* As an exception, if the next filter returned XZ_STREAM_END,
* we can do that too, since the last few bytes that remain
* unfiltered are meant to remain unfiltered.
*/
if (s->ret == XZ_STREAM_END)
return XZ_STREAM_END;
s->temp.size = b->out_pos - out_start;
b->out_pos -= s->temp.size;
memcpy(s->temp.buf, b->out + b->out_pos, s->temp.size);
/*
* If there wasn't enough input to the next filter to fill
* the output buffer with unfiltered data, there's no point
* to try decoding more data to temp.
*/
if (b->out_pos + s->temp.size < b->out_size)
return XZ_OK;
}
/*
* We have unfiltered data in temp. If the output buffer isn't full
* yet, try to fill the temp buffer by decoding more data from the
* next filter. Apply the BCJ filter on temp. Then we hopefully can
* fill the actual output buffer by copying filtered data from temp.
* A mix of filtered and unfiltered data may be left in temp; it will
* be taken care on the next call to this function.
*/
if (b->out_pos < b->out_size) {
/* Make b->out{,_pos,_size} temporarily point to s->temp. */
s->out = b->out;
s->out_pos = b->out_pos;
s->out_size = b->out_size;
b->out = s->temp.buf;
b->out_pos = s->temp.size;
b->out_size = sizeof(s->temp.buf);
s->ret = xz_dec_lzma2_run(lzma2, b);
s->temp.size = b->out_pos;
b->out = s->out;
b->out_pos = s->out_pos;
b->out_size = s->out_size;
if (s->ret != XZ_OK && s->ret != XZ_STREAM_END)
return s->ret;
bcj_apply(s, s->temp.buf, &s->temp.filtered, s->temp.size);
/*
* If the next filter returned XZ_STREAM_END, we mark that
* everything is filtered, since the last unfiltered bytes
* of the stream are meant to be left as is.
*/
if (s->ret == XZ_STREAM_END)
s->temp.filtered = s->temp.size;
bcj_flush(s, b);
if (s->temp.filtered > 0)
return XZ_OK;
}
return s->ret;
}
XZ_EXTERN struct xz_dec_bcj *xz_dec_bcj_create(bool single_call)
{
struct xz_dec_bcj *s = kmalloc(sizeof(*s), GFP_KERNEL);
if (s != NULL)
s->single_call = single_call;
return s;
}
XZ_EXTERN enum xz_ret xz_dec_bcj_reset(struct xz_dec_bcj *s, uint8_t id)
{
switch (id) {
#ifdef XZ_DEC_X86
case BCJ_X86:
#endif
#ifdef XZ_DEC_POWERPC
case BCJ_POWERPC:
#endif
#ifdef XZ_DEC_IA64
case BCJ_IA64:
#endif
#ifdef XZ_DEC_ARM
case BCJ_ARM:
#endif
#ifdef XZ_DEC_ARMTHUMB
case BCJ_ARMTHUMB:
#endif
#ifdef XZ_DEC_SPARC
case BCJ_SPARC:
#endif
break;
default:
/* Unsupported Filter ID */
return XZ_OPTIONS_ERROR;
}
s->type = id;
s->ret = XZ_OK;
s->pos = 0;
s->x86_prev_mask = 0;
s->temp.filtered = 0;
s->temp.size = 0;
return XZ_OK;
}
#endif

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/*
* .xz Stream decoder
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#include "xz_private.h"
#include "xz_stream.h"
/* Hash used to validate the Index field */
struct xz_dec_hash {
vli_type unpadded;
vli_type uncompressed;
uint32_t crc32;
};
struct xz_dec {
/* Position in dec_main() */
enum {
SEQ_STREAM_HEADER,
SEQ_BLOCK_START,
SEQ_BLOCK_HEADER,
SEQ_BLOCK_UNCOMPRESS,
SEQ_BLOCK_PADDING,
SEQ_BLOCK_CHECK,
SEQ_INDEX,
SEQ_INDEX_PADDING,
SEQ_INDEX_CRC32,
SEQ_STREAM_FOOTER
} sequence;
/* Position in variable-length integers and Check fields */
uint32_t pos;
/* Variable-length integer decoded by dec_vli() */
vli_type vli;
/* Saved in_pos and out_pos */
size_t in_start;
size_t out_start;
/* CRC32 value in Block or Index */
uint32_t crc32;
/* Type of the integrity check calculated from uncompressed data */
enum xz_check check_type;
/* Operation mode */
enum xz_mode mode;
/*
* True if the next call to xz_dec_run() is allowed to return
* XZ_BUF_ERROR.
*/
bool allow_buf_error;
/* Information stored in Block Header */
struct {
/*
* Value stored in the Compressed Size field, or
* VLI_UNKNOWN if Compressed Size is not present.
*/
vli_type compressed;
/*
* Value stored in the Uncompressed Size field, or
* VLI_UNKNOWN if Uncompressed Size is not present.
*/
vli_type uncompressed;
/* Size of the Block Header field */
uint32_t size;
} block_header;
/* Information collected when decoding Blocks */
struct {
/* Observed compressed size of the current Block */
vli_type compressed;
/* Observed uncompressed size of the current Block */
vli_type uncompressed;
/* Number of Blocks decoded so far */
vli_type count;
/*
* Hash calculated from the Block sizes. This is used to
* validate the Index field.
*/
struct xz_dec_hash hash;
} block;
/* Variables needed when verifying the Index field */
struct {
/* Position in dec_index() */
enum {
SEQ_INDEX_COUNT,
SEQ_INDEX_UNPADDED,
SEQ_INDEX_UNCOMPRESSED
} sequence;
/* Size of the Index in bytes */
vli_type size;
/* Number of Records (matches block.count in valid files) */
vli_type count;
/*
* Hash calculated from the Records (matches block.hash in
* valid files).
*/
struct xz_dec_hash hash;
} index;
/*
* Temporary buffer needed to hold Stream Header, Block Header,
* and Stream Footer. The Block Header is the biggest (1 KiB)
* so we reserve space according to that. buf[] has to be aligned
* to a multiple of four bytes; the size_t variables before it
* should guarantee this.
*/
struct {
size_t pos;
size_t size;
uint8_t buf[1024];
} temp;
struct xz_dec_lzma2 *lzma2;
#ifdef XZ_DEC_BCJ
struct xz_dec_bcj *bcj;
bool bcj_active;
#endif
};
#ifdef XZ_DEC_ANY_CHECK
/* Sizes of the Check field with different Check IDs */
static const uint8_t check_sizes[16] = {
0,
4, 4, 4,
8, 8, 8,
16, 16, 16,
32, 32, 32,
64, 64, 64
};
#endif
/*
* Fill s->temp by copying data starting from b->in[b->in_pos]. Caller
* must have set s->temp.pos to indicate how much data we are supposed
* to copy into s->temp.buf. Return true once s->temp.pos has reached
* s->temp.size.
*/
static bool fill_temp(struct xz_dec *s, struct xz_buf *b)
{
size_t copy_size = min_t(size_t,
b->in_size - b->in_pos, s->temp.size - s->temp.pos);
memcpy(s->temp.buf + s->temp.pos, b->in + b->in_pos, copy_size);
b->in_pos += copy_size;
s->temp.pos += copy_size;
if (s->temp.pos == s->temp.size) {
s->temp.pos = 0;
return true;
}
return false;
}
/* Decode a variable-length integer (little-endian base-128 encoding) */
static enum xz_ret dec_vli(struct xz_dec *s, const uint8_t *in,
size_t *in_pos, size_t in_size)
{
uint8_t byte;
if (s->pos == 0)
s->vli = 0;
while (*in_pos < in_size) {
byte = in[*in_pos];
++*in_pos;
s->vli |= (vli_type)(byte & 0x7F) << s->pos;
if ((byte & 0x80) == 0) {
/* Don't allow non-minimal encodings. */
if (byte == 0 && s->pos != 0)
return XZ_DATA_ERROR;
s->pos = 0;
return XZ_STREAM_END;
}
s->pos += 7;
if (s->pos == 7 * VLI_BYTES_MAX)
return XZ_DATA_ERROR;
}
return XZ_OK;
}
/*
* Decode the Compressed Data field from a Block. Update and validate
* the observed compressed and uncompressed sizes of the Block so that
* they don't exceed the values possibly stored in the Block Header
* (validation assumes that no integer overflow occurs, since vli_type
* is normally uint64_t). Update the CRC32 if presence of the CRC32
* field was indicated in Stream Header.
*
* Once the decoding is finished, validate that the observed sizes match
* the sizes possibly stored in the Block Header. Update the hash and
* Block count, which are later used to validate the Index field.
*/
static enum xz_ret dec_block(struct xz_dec *s, struct xz_buf *b)
{
enum xz_ret ret;
s->in_start = b->in_pos;
s->out_start = b->out_pos;
#ifdef XZ_DEC_BCJ
if (s->bcj_active)
ret = xz_dec_bcj_run(s->bcj, s->lzma2, b);
else
#endif
ret = xz_dec_lzma2_run(s->lzma2, b);
s->block.compressed += b->in_pos - s->in_start;
s->block.uncompressed += b->out_pos - s->out_start;
/*
* There is no need to separately check for VLI_UNKNOWN, since
* the observed sizes are always smaller than VLI_UNKNOWN.
*/
if (s->block.compressed > s->block_header.compressed
|| s->block.uncompressed
> s->block_header.uncompressed)
return XZ_DATA_ERROR;
if (s->check_type == XZ_CHECK_CRC32)
s->crc32 = xz_crc32(b->out + s->out_start,
b->out_pos - s->out_start, s->crc32);
if (ret == XZ_STREAM_END) {
if (s->block_header.compressed != VLI_UNKNOWN
&& s->block_header.compressed
!= s->block.compressed)
return XZ_DATA_ERROR;
if (s->block_header.uncompressed != VLI_UNKNOWN
&& s->block_header.uncompressed
!= s->block.uncompressed)
return XZ_DATA_ERROR;
s->block.hash.unpadded += s->block_header.size
+ s->block.compressed;
#ifdef XZ_DEC_ANY_CHECK
s->block.hash.unpadded += check_sizes[s->check_type];
#else
if (s->check_type == XZ_CHECK_CRC32)
s->block.hash.unpadded += 4;
#endif
s->block.hash.uncompressed += s->block.uncompressed;
s->block.hash.crc32 = xz_crc32(
(const uint8_t *)&s->block.hash,
sizeof(s->block.hash), s->block.hash.crc32);
++s->block.count;
}
return ret;
}
/* Update the Index size and the CRC32 value. */
static void index_update(struct xz_dec *s, const struct xz_buf *b)
{
size_t in_used = b->in_pos - s->in_start;
s->index.size += in_used;
s->crc32 = xz_crc32(b->in + s->in_start, in_used, s->crc32);
}
/*
* Decode the Number of Records, Unpadded Size, and Uncompressed Size
* fields from the Index field. That is, Index Padding and CRC32 are not
* decoded by this function.
*
* This can return XZ_OK (more input needed), XZ_STREAM_END (everything
* successfully decoded), or XZ_DATA_ERROR (input is corrupt).
*/
static enum xz_ret dec_index(struct xz_dec *s, struct xz_buf *b)
{
enum xz_ret ret;
do {
ret = dec_vli(s, b->in, &b->in_pos, b->in_size);
if (ret != XZ_STREAM_END) {
index_update(s, b);
return ret;
}
switch (s->index.sequence) {
case SEQ_INDEX_COUNT:
s->index.count = s->vli;
/*
* Validate that the Number of Records field
* indicates the same number of Records as
* there were Blocks in the Stream.
*/
if (s->index.count != s->block.count)
return XZ_DATA_ERROR;
s->index.sequence = SEQ_INDEX_UNPADDED;
break;
case SEQ_INDEX_UNPADDED:
s->index.hash.unpadded += s->vli;
s->index.sequence = SEQ_INDEX_UNCOMPRESSED;
break;
case SEQ_INDEX_UNCOMPRESSED:
s->index.hash.uncompressed += s->vli;
s->index.hash.crc32 = xz_crc32(
(const uint8_t *)&s->index.hash,
sizeof(s->index.hash),
s->index.hash.crc32);
--s->index.count;
s->index.sequence = SEQ_INDEX_UNPADDED;
break;
}
} while (s->index.count > 0);
return XZ_STREAM_END;
}
/*
* Validate that the next four input bytes match the value of s->crc32.
* s->pos must be zero when starting to validate the first byte.
*/
static enum xz_ret crc32_validate(struct xz_dec *s, struct xz_buf *b)
{
do {
if (b->in_pos == b->in_size)
return XZ_OK;
if (((s->crc32 >> s->pos) & 0xFF) != b->in[b->in_pos++])
return XZ_DATA_ERROR;
s->pos += 8;
} while (s->pos < 32);
s->crc32 = 0;
s->pos = 0;
return XZ_STREAM_END;
}
#ifdef XZ_DEC_ANY_CHECK
/*
* Skip over the Check field when the Check ID is not supported.
* Returns true once the whole Check field has been skipped over.
*/
static bool check_skip(struct xz_dec *s, struct xz_buf *b)
{
while (s->pos < check_sizes[s->check_type]) {
if (b->in_pos == b->in_size)
return false;
++b->in_pos;
++s->pos;
}
s->pos = 0;
return true;
}
#endif
/* Decode the Stream Header field (the first 12 bytes of the .xz Stream). */
static enum xz_ret dec_stream_header(struct xz_dec *s)
{
if (!memeq(s->temp.buf, HEADER_MAGIC, HEADER_MAGIC_SIZE))
return XZ_FORMAT_ERROR;
if (xz_crc32(s->temp.buf + HEADER_MAGIC_SIZE, 2, 0)
!= get_le32(s->temp.buf + HEADER_MAGIC_SIZE + 2))
return XZ_DATA_ERROR;
if (s->temp.buf[HEADER_MAGIC_SIZE] != 0)
return XZ_OPTIONS_ERROR;
/*
* Of integrity checks, we support only none (Check ID = 0) and
* CRC32 (Check ID = 1). However, if XZ_DEC_ANY_CHECK is defined,
* we will accept other check types too, but then the check won't
* be verified and a warning (XZ_UNSUPPORTED_CHECK) will be given.
*/
s->check_type = s->temp.buf[HEADER_MAGIC_SIZE + 1];
#ifdef XZ_DEC_ANY_CHECK
if (s->check_type > XZ_CHECK_MAX)
return XZ_OPTIONS_ERROR;
if (s->check_type > XZ_CHECK_CRC32)
return XZ_UNSUPPORTED_CHECK;
#else
if (s->check_type > XZ_CHECK_CRC32)
return XZ_OPTIONS_ERROR;
#endif
return XZ_OK;
}
/* Decode the Stream Footer field (the last 12 bytes of the .xz Stream) */
static enum xz_ret dec_stream_footer(struct xz_dec *s)
{
if (!memeq(s->temp.buf + 10, FOOTER_MAGIC, FOOTER_MAGIC_SIZE))
return XZ_DATA_ERROR;
if (xz_crc32(s->temp.buf + 4, 6, 0) != get_le32(s->temp.buf))
return XZ_DATA_ERROR;
/*
* Validate Backward Size. Note that we never added the size of the
* Index CRC32 field to s->index.size, thus we use s->index.size / 4
* instead of s->index.size / 4 - 1.
*/
if ((s->index.size >> 2) != get_le32(s->temp.buf + 4))
return XZ_DATA_ERROR;
if (s->temp.buf[8] != 0 || s->temp.buf[9] != s->check_type)
return XZ_DATA_ERROR;
/*
* Use XZ_STREAM_END instead of XZ_OK to be more convenient
* for the caller.
*/
return XZ_STREAM_END;
}
/* Decode the Block Header and initialize the filter chain. */
static enum xz_ret dec_block_header(struct xz_dec *s)
{
enum xz_ret ret;
/*
* Validate the CRC32. We know that the temp buffer is at least
* eight bytes so this is safe.
*/
s->temp.size -= 4;
if (xz_crc32(s->temp.buf, s->temp.size, 0)
!= get_le32(s->temp.buf + s->temp.size))
return XZ_DATA_ERROR;
s->temp.pos = 2;
/*
* Catch unsupported Block Flags. We support only one or two filters
* in the chain, so we catch that with the same test.
*/
#ifdef XZ_DEC_BCJ
if (s->temp.buf[1] & 0x3E)
#else
if (s->temp.buf[1] & 0x3F)
#endif
return XZ_OPTIONS_ERROR;
/* Compressed Size */
if (s->temp.buf[1] & 0x40) {
if (dec_vli(s, s->temp.buf, &s->temp.pos, s->temp.size)
!= XZ_STREAM_END)
return XZ_DATA_ERROR;
s->block_header.compressed = s->vli;
} else {
s->block_header.compressed = VLI_UNKNOWN;
}
/* Uncompressed Size */
if (s->temp.buf[1] & 0x80) {
if (dec_vli(s, s->temp.buf, &s->temp.pos, s->temp.size)
!= XZ_STREAM_END)
return XZ_DATA_ERROR;
s->block_header.uncompressed = s->vli;
} else {
s->block_header.uncompressed = VLI_UNKNOWN;
}
#ifdef XZ_DEC_BCJ
/* If there are two filters, the first one must be a BCJ filter. */
s->bcj_active = s->temp.buf[1] & 0x01;
if (s->bcj_active) {
if (s->temp.size - s->temp.pos < 2)
return XZ_OPTIONS_ERROR;
ret = xz_dec_bcj_reset(s->bcj, s->temp.buf[s->temp.pos++]);
if (ret != XZ_OK)
return ret;
/*
* We don't support custom start offset,
* so Size of Properties must be zero.
*/
if (s->temp.buf[s->temp.pos++] != 0x00)
return XZ_OPTIONS_ERROR;
}
#endif
/* Valid Filter Flags always take at least two bytes. */
if (s->temp.size - s->temp.pos < 2)
return XZ_DATA_ERROR;
/* Filter ID = LZMA2 */
if (s->temp.buf[s->temp.pos++] != 0x21)
return XZ_OPTIONS_ERROR;
/* Size of Properties = 1-byte Filter Properties */
if (s->temp.buf[s->temp.pos++] != 0x01)
return XZ_OPTIONS_ERROR;
/* Filter Properties contains LZMA2 dictionary size. */
if (s->temp.size - s->temp.pos < 1)
return XZ_DATA_ERROR;
ret = xz_dec_lzma2_reset(s->lzma2, s->temp.buf[s->temp.pos++]);
if (ret != XZ_OK)
return ret;
/* The rest must be Header Padding. */
while (s->temp.pos < s->temp.size)
if (s->temp.buf[s->temp.pos++] != 0x00)
return XZ_OPTIONS_ERROR;
s->temp.pos = 0;
s->block.compressed = 0;
s->block.uncompressed = 0;
return XZ_OK;
}
static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
{
enum xz_ret ret;
/*
* Store the start position for the case when we are in the middle
* of the Index field.
*/
s->in_start = b->in_pos;
while (true) {
switch (s->sequence) {
case SEQ_STREAM_HEADER:
/*
* Stream Header is copied to s->temp, and then
* decoded from there. This way if the caller
* gives us only little input at a time, we can
* still keep the Stream Header decoding code
* simple. Similar approach is used in many places
* in this file.
*/
if (!fill_temp(s, b))
return XZ_OK;
/*
* If dec_stream_header() returns
* XZ_UNSUPPORTED_CHECK, it is still possible
* to continue decoding if working in multi-call
* mode. Thus, update s->sequence before calling
* dec_stream_header().
*/
s->sequence = SEQ_BLOCK_START;
ret = dec_stream_header(s);
if (ret != XZ_OK)
return ret;
case SEQ_BLOCK_START:
/* We need one byte of input to continue. */
if (b->in_pos == b->in_size)
return XZ_OK;
/* See if this is the beginning of the Index field. */
if (b->in[b->in_pos] == 0) {
s->in_start = b->in_pos++;
s->sequence = SEQ_INDEX;
break;
}
/*
* Calculate the size of the Block Header and
* prepare to decode it.
*/
s->block_header.size
= ((uint32_t)b->in[b->in_pos] + 1) * 4;
s->temp.size = s->block_header.size;
s->temp.pos = 0;
s->sequence = SEQ_BLOCK_HEADER;
case SEQ_BLOCK_HEADER:
if (!fill_temp(s, b))
return XZ_OK;
ret = dec_block_header(s);
if (ret != XZ_OK)
return ret;
s->sequence = SEQ_BLOCK_UNCOMPRESS;
case SEQ_BLOCK_UNCOMPRESS:
ret = dec_block(s, b);
if (ret != XZ_STREAM_END)
return ret;
s->sequence = SEQ_BLOCK_PADDING;
case SEQ_BLOCK_PADDING:
/*
* Size of Compressed Data + Block Padding
* must be a multiple of four. We don't need
* s->block.compressed for anything else
* anymore, so we use it here to test the size
* of the Block Padding field.
*/
while (s->block.compressed & 3) {
if (b->in_pos == b->in_size)
return XZ_OK;
if (b->in[b->in_pos++] != 0)
return XZ_DATA_ERROR;
++s->block.compressed;
}
s->sequence = SEQ_BLOCK_CHECK;
case SEQ_BLOCK_CHECK:
if (s->check_type == XZ_CHECK_CRC32) {
ret = crc32_validate(s, b);
if (ret != XZ_STREAM_END)
return ret;
}
#ifdef XZ_DEC_ANY_CHECK
else if (!check_skip(s, b)) {
return XZ_OK;
}
#endif
s->sequence = SEQ_BLOCK_START;
break;
case SEQ_INDEX:
ret = dec_index(s, b);
if (ret != XZ_STREAM_END)
return ret;
s->sequence = SEQ_INDEX_PADDING;
case SEQ_INDEX_PADDING:
while ((s->index.size + (b->in_pos - s->in_start))
& 3) {
if (b->in_pos == b->in_size) {
index_update(s, b);
return XZ_OK;
}
if (b->in[b->in_pos++] != 0)
return XZ_DATA_ERROR;
}
/* Finish the CRC32 value and Index size. */
index_update(s, b);
/* Compare the hashes to validate the Index field. */
if (!memeq(&s->block.hash, &s->index.hash,
sizeof(s->block.hash)))
return XZ_DATA_ERROR;
s->sequence = SEQ_INDEX_CRC32;
case SEQ_INDEX_CRC32:
ret = crc32_validate(s, b);
if (ret != XZ_STREAM_END)
return ret;
s->temp.size = STREAM_HEADER_SIZE;
s->sequence = SEQ_STREAM_FOOTER;
case SEQ_STREAM_FOOTER:
if (!fill_temp(s, b))
return XZ_OK;
return dec_stream_footer(s);
}
}
/* Never reached */
}
/*
* xz_dec_run() is a wrapper for dec_main() to handle some special cases in
* multi-call and single-call decoding.
*
* In multi-call mode, we must return XZ_BUF_ERROR when it seems clear that we
* are not going to make any progress anymore. This is to prevent the caller
* from calling us infinitely when the input file is truncated or otherwise
* corrupt. Since zlib-style API allows that the caller fills the input buffer
* only when the decoder doesn't produce any new output, we have to be careful
* to avoid returning XZ_BUF_ERROR too easily: XZ_BUF_ERROR is returned only
* after the second consecutive call to xz_dec_run() that makes no progress.
*
* In single-call mode, if we couldn't decode everything and no error
* occurred, either the input is truncated or the output buffer is too small.
* Since we know that the last input byte never produces any output, we know
* that if all the input was consumed and decoding wasn't finished, the file
* must be corrupt. Otherwise the output buffer has to be too small or the
* file is corrupt in a way that decoding it produces too big output.
*
* If single-call decoding fails, we reset b->in_pos and b->out_pos back to
* their original values. This is because with some filter chains there won't
* be any valid uncompressed data in the output buffer unless the decoding
* actually succeeds (that's the price to pay of using the output buffer as
* the workspace).
*/
XZ_EXTERN enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b)
{
size_t in_start;
size_t out_start;
enum xz_ret ret;
if (DEC_IS_SINGLE(s->mode))
xz_dec_reset(s);
in_start = b->in_pos;
out_start = b->out_pos;
ret = dec_main(s, b);
if (DEC_IS_SINGLE(s->mode)) {
if (ret == XZ_OK)
ret = b->in_pos == b->in_size
? XZ_DATA_ERROR : XZ_BUF_ERROR;
if (ret != XZ_STREAM_END) {
b->in_pos = in_start;
b->out_pos = out_start;
}
} else if (ret == XZ_OK && in_start == b->in_pos
&& out_start == b->out_pos) {
if (s->allow_buf_error)
ret = XZ_BUF_ERROR;
s->allow_buf_error = true;
} else {
s->allow_buf_error = false;
}
return ret;
}
XZ_EXTERN struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max)
{
struct xz_dec *s = kmalloc(sizeof(*s), GFP_KERNEL);
if (s == NULL)
return NULL;
s->mode = mode;
#ifdef XZ_DEC_BCJ
s->bcj = xz_dec_bcj_create(DEC_IS_SINGLE(mode));
if (s->bcj == NULL)
goto error_bcj;
#endif
s->lzma2 = xz_dec_lzma2_create(mode, dict_max);
if (s->lzma2 == NULL)
goto error_lzma2;
xz_dec_reset(s);
return s;
error_lzma2:
#ifdef XZ_DEC_BCJ
xz_dec_bcj_end(s->bcj);
error_bcj:
#endif
kfree(s);
return NULL;
}
XZ_EXTERN void xz_dec_reset(struct xz_dec *s)
{
s->sequence = SEQ_STREAM_HEADER;
s->allow_buf_error = false;
s->pos = 0;
s->crc32 = 0;
memzero(&s->block, sizeof(s->block));
memzero(&s->index, sizeof(s->index));
s->temp.pos = 0;
s->temp.size = STREAM_HEADER_SIZE;
}
XZ_EXTERN void xz_dec_end(struct xz_dec *s)
{
if (s != NULL) {
xz_dec_lzma2_end(s->lzma2);
#ifdef XZ_DEC_BCJ
xz_dec_bcj_end(s->bcj);
#endif
kfree(s);
}
}

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/*
* XZ decoder module information
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#include <linux/module.h>
#include <linux/xz.h>
EXPORT_SYMBOL(xz_dec_init);
EXPORT_SYMBOL(xz_dec_reset);
EXPORT_SYMBOL(xz_dec_run);
EXPORT_SYMBOL(xz_dec_end);
MODULE_DESCRIPTION("XZ decompressor");
MODULE_VERSION("1.0");
MODULE_AUTHOR("Lasse Collin <lasse.collin@tukaani.org> and Igor Pavlov");
/*
* This code is in the public domain, but in Linux it's simplest to just
* say it's GPL and consider the authors as the copyright holders.
*/
MODULE_LICENSE("GPL");

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/*
* XZ decoder tester
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/crc32.h>
#include <linux/xz.h>
/* Maximum supported dictionary size */
#define DICT_MAX (1 << 20)
/* Device name to pass to register_chrdev(). */
#define DEVICE_NAME "xz_dec_test"
/* Dynamically allocated device major number */
static int device_major;
/*
* We reuse the same decoder state, and thus can decode only one
* file at a time.
*/
static bool device_is_open;
/* XZ decoder state */
static struct xz_dec *state;
/*
* Return value of xz_dec_run(). We need to avoid calling xz_dec_run() after
* it has returned XZ_STREAM_END, so we make this static.
*/
static enum xz_ret ret;
/*
* Input and output buffers. The input buffer is used as a temporary safe
* place for the data coming from the userspace.
*/
static uint8_t buffer_in[1024];
static uint8_t buffer_out[1024];
/*
* Structure to pass the input and output buffers to the XZ decoder.
* A few of the fields are never modified so we initialize them here.
*/
static struct xz_buf buffers = {
.in = buffer_in,
.out = buffer_out,
.out_size = sizeof(buffer_out)
};
/*
* CRC32 of uncompressed data. This is used to give the user a simple way
* to check that the decoder produces correct output.
*/
static uint32_t crc;
static int xz_dec_test_open(struct inode *i, struct file *f)
{
if (device_is_open)
return -EBUSY;
device_is_open = true;
xz_dec_reset(state);
ret = XZ_OK;
crc = 0xFFFFFFFF;
buffers.in_pos = 0;
buffers.in_size = 0;
buffers.out_pos = 0;
printk(KERN_INFO DEVICE_NAME ": opened\n");
return 0;
}
static int xz_dec_test_release(struct inode *i, struct file *f)
{
device_is_open = false;
if (ret == XZ_OK)
printk(KERN_INFO DEVICE_NAME ": input was truncated\n");
printk(KERN_INFO DEVICE_NAME ": closed\n");
return 0;
}
/*
* Decode the data given to us from the userspace. CRC32 of the uncompressed
* data is calculated and is printed at the end of successful decoding. The
* uncompressed data isn't stored anywhere for further use.
*
* The .xz file must have exactly one Stream and no Stream Padding. The data
* after the first Stream is considered to be garbage.
*/
static ssize_t xz_dec_test_write(struct file *file, const char __user *buf,
size_t size, loff_t *pos)
{
size_t remaining;
if (ret != XZ_OK) {
if (size > 0)
printk(KERN_INFO DEVICE_NAME ": %zu bytes of "
"garbage at the end of the file\n",
size);
return -ENOSPC;
}
printk(KERN_INFO DEVICE_NAME ": decoding %zu bytes of input\n",
size);
remaining = size;
while ((remaining > 0 || buffers.out_pos == buffers.out_size)
&& ret == XZ_OK) {
if (buffers.in_pos == buffers.in_size) {
buffers.in_pos = 0;
buffers.in_size = min(remaining, sizeof(buffer_in));
if (copy_from_user(buffer_in, buf, buffers.in_size))
return -EFAULT;
buf += buffers.in_size;
remaining -= buffers.in_size;
}
buffers.out_pos = 0;
ret = xz_dec_run(state, &buffers);
crc = crc32(crc, buffer_out, buffers.out_pos);
}
switch (ret) {
case XZ_OK:
printk(KERN_INFO DEVICE_NAME ": XZ_OK\n");
return size;
case XZ_STREAM_END:
printk(KERN_INFO DEVICE_NAME ": XZ_STREAM_END, "
"CRC32 = 0x%08X\n", ~crc);
return size - remaining - (buffers.in_size - buffers.in_pos);
case XZ_MEMLIMIT_ERROR:
printk(KERN_INFO DEVICE_NAME ": XZ_MEMLIMIT_ERROR\n");
break;
case XZ_FORMAT_ERROR:
printk(KERN_INFO DEVICE_NAME ": XZ_FORMAT_ERROR\n");
break;
case XZ_OPTIONS_ERROR:
printk(KERN_INFO DEVICE_NAME ": XZ_OPTIONS_ERROR\n");
break;
case XZ_DATA_ERROR:
printk(KERN_INFO DEVICE_NAME ": XZ_DATA_ERROR\n");
break;
case XZ_BUF_ERROR:
printk(KERN_INFO DEVICE_NAME ": XZ_BUF_ERROR\n");
break;
default:
printk(KERN_INFO DEVICE_NAME ": Bug detected!\n");
break;
}
return -EIO;
}
/* Allocate the XZ decoder state and register the character device. */
static int __init xz_dec_test_init(void)
{
static const struct file_operations fileops = {
.owner = THIS_MODULE,
.open = &xz_dec_test_open,
.release = &xz_dec_test_release,
.write = &xz_dec_test_write
};
state = xz_dec_init(XZ_PREALLOC, DICT_MAX);
if (state == NULL)
return -ENOMEM;
device_major = register_chrdev(0, DEVICE_NAME, &fileops);
if (device_major < 0) {
xz_dec_end(state);
return device_major;
}
printk(KERN_INFO DEVICE_NAME ": module loaded\n");
printk(KERN_INFO DEVICE_NAME ": Create a device node with "
"'mknod " DEVICE_NAME " c %d 0' and write .xz files "
"to it.\n", device_major);
return 0;
}
static void __exit xz_dec_test_exit(void)
{
unregister_chrdev(device_major, DEVICE_NAME);
xz_dec_end(state);
printk(KERN_INFO DEVICE_NAME ": module unloaded\n");
}
module_init(xz_dec_test_init);
module_exit(xz_dec_test_exit);
MODULE_DESCRIPTION("XZ decompressor tester");
MODULE_VERSION("1.0");
MODULE_AUTHOR("Lasse Collin <lasse.collin@tukaani.org>");
/*
* This code is in the public domain, but in Linux it's simplest to just
* say it's GPL and consider the authors as the copyright holders.
*/
MODULE_LICENSE("GPL");

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/*
* LZMA2 definitions
*
* Authors: Lasse Collin <lasse.collin@tukaani.org>
* Igor Pavlov <http://7-zip.org/>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#ifndef XZ_LZMA2_H
#define XZ_LZMA2_H
/* Range coder constants */
#define RC_SHIFT_BITS 8
#define RC_TOP_BITS 24
#define RC_TOP_VALUE (1 << RC_TOP_BITS)
#define RC_BIT_MODEL_TOTAL_BITS 11
#define RC_BIT_MODEL_TOTAL (1 << RC_BIT_MODEL_TOTAL_BITS)
#define RC_MOVE_BITS 5
/*
* Maximum number of position states. A position state is the lowest pb
* number of bits of the current uncompressed offset. In some places there
* are different sets of probabilities for different position states.
*/
#define POS_STATES_MAX (1 << 4)
/*
* This enum is used to track which LZMA symbols have occurred most recently
* and in which order. This information is used to predict the next symbol.
*
* Symbols:
* - Literal: One 8-bit byte
* - Match: Repeat a chunk of data at some distance
* - Long repeat: Multi-byte match at a recently seen distance
* - Short repeat: One-byte repeat at a recently seen distance
*
* The symbol names are in from STATE_oldest_older_previous. REP means
* either short or long repeated match, and NONLIT means any non-literal.
*/
enum lzma_state {
STATE_LIT_LIT,
STATE_MATCH_LIT_LIT,
STATE_REP_LIT_LIT,
STATE_SHORTREP_LIT_LIT,
STATE_MATCH_LIT,
STATE_REP_LIT,
STATE_SHORTREP_LIT,
STATE_LIT_MATCH,
STATE_LIT_LONGREP,
STATE_LIT_SHORTREP,
STATE_NONLIT_MATCH,
STATE_NONLIT_REP
};
/* Total number of states */
#define STATES 12
/* The lowest 7 states indicate that the previous state was a literal. */
#define LIT_STATES 7
/* Indicate that the latest symbol was a literal. */
static inline void lzma_state_literal(enum lzma_state *state)
{
if (*state <= STATE_SHORTREP_LIT_LIT)
*state = STATE_LIT_LIT;
else if (*state <= STATE_LIT_SHORTREP)
*state -= 3;
else
*state -= 6;
}
/* Indicate that the latest symbol was a match. */
static inline void lzma_state_match(enum lzma_state *state)
{
*state = *state < LIT_STATES ? STATE_LIT_MATCH : STATE_NONLIT_MATCH;
}
/* Indicate that the latest state was a long repeated match. */
static inline void lzma_state_long_rep(enum lzma_state *state)
{
*state = *state < LIT_STATES ? STATE_LIT_LONGREP : STATE_NONLIT_REP;
}
/* Indicate that the latest symbol was a short match. */
static inline void lzma_state_short_rep(enum lzma_state *state)
{
*state = *state < LIT_STATES ? STATE_LIT_SHORTREP : STATE_NONLIT_REP;
}
/* Test if the previous symbol was a literal. */
static inline bool lzma_state_is_literal(enum lzma_state state)
{
return state < LIT_STATES;
}
/* Each literal coder is divided in three sections:
* - 0x001-0x0FF: Without match byte
* - 0x101-0x1FF: With match byte; match bit is 0
* - 0x201-0x2FF: With match byte; match bit is 1
*
* Match byte is used when the previous LZMA symbol was something else than
* a literal (that is, it was some kind of match).
*/
#define LITERAL_CODER_SIZE 0x300
/* Maximum number of literal coders */
#define LITERAL_CODERS_MAX (1 << 4)
/* Minimum length of a match is two bytes. */
#define MATCH_LEN_MIN 2
/* Match length is encoded with 4, 5, or 10 bits.
*
* Length Bits
* 2-9 4 = Choice=0 + 3 bits
* 10-17 5 = Choice=1 + Choice2=0 + 3 bits
* 18-273 10 = Choice=1 + Choice2=1 + 8 bits
*/
#define LEN_LOW_BITS 3
#define LEN_LOW_SYMBOLS (1 << LEN_LOW_BITS)
#define LEN_MID_BITS 3
#define LEN_MID_SYMBOLS (1 << LEN_MID_BITS)
#define LEN_HIGH_BITS 8
#define LEN_HIGH_SYMBOLS (1 << LEN_HIGH_BITS)
#define LEN_SYMBOLS (LEN_LOW_SYMBOLS + LEN_MID_SYMBOLS + LEN_HIGH_SYMBOLS)
/*
* Maximum length of a match is 273 which is a result of the encoding
* described above.
*/
#define MATCH_LEN_MAX (MATCH_LEN_MIN + LEN_SYMBOLS - 1)
/*
* Different sets of probabilities are used for match distances that have
* very short match length: Lengths of 2, 3, and 4 bytes have a separate
* set of probabilities for each length. The matches with longer length
* use a shared set of probabilities.
*/
#define DIST_STATES 4
/*
* Get the index of the appropriate probability array for decoding
* the distance slot.
*/
static inline uint32_t lzma_get_dist_state(uint32_t len)
{
return len < DIST_STATES + MATCH_LEN_MIN
? len - MATCH_LEN_MIN : DIST_STATES - 1;
}
/*
* The highest two bits of a 32-bit match distance are encoded using six bits.
* This six-bit value is called a distance slot. This way encoding a 32-bit
* value takes 6-36 bits, larger values taking more bits.
*/
#define DIST_SLOT_BITS 6
#define DIST_SLOTS (1 << DIST_SLOT_BITS)
/* Match distances up to 127 are fully encoded using probabilities. Since
* the highest two bits (distance slot) are always encoded using six bits,
* the distances 0-3 don't need any additional bits to encode, since the
* distance slot itself is the same as the actual distance. DIST_MODEL_START
* indicates the first distance slot where at least one additional bit is
* needed.
*/
#define DIST_MODEL_START 4
/*
* Match distances greater than 127 are encoded in three pieces:
* - distance slot: the highest two bits
* - direct bits: 2-26 bits below the highest two bits
* - alignment bits: four lowest bits
*
* Direct bits don't use any probabilities.
*
* The distance slot value of 14 is for distances 128-191.
*/
#define DIST_MODEL_END 14
/* Distance slots that indicate a distance <= 127. */
#define FULL_DISTANCES_BITS (DIST_MODEL_END / 2)
#define FULL_DISTANCES (1 << FULL_DISTANCES_BITS)
/*
* For match distances greater than 127, only the highest two bits and the
* lowest four bits (alignment) is encoded using probabilities.
*/
#define ALIGN_BITS 4
#define ALIGN_SIZE (1 << ALIGN_BITS)
#define ALIGN_MASK (ALIGN_SIZE - 1)
/* Total number of all probability variables */
#define PROBS_TOTAL (1846 + LITERAL_CODERS_MAX * LITERAL_CODER_SIZE)
/*
* LZMA remembers the four most recent match distances. Reusing these
* distances tends to take less space than re-encoding the actual
* distance value.
*/
#define REPS 4
#endif

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/*
* Private includes and definitions
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#ifndef XZ_PRIVATE_H
#define XZ_PRIVATE_H
#ifdef __KERNEL__
# include <linux/xz.h>
# include <linux/kernel.h>
# include <asm/unaligned.h>
/* XZ_PREBOOT may be defined only via decompress_unxz.c. */
# ifndef XZ_PREBOOT
# include <linux/slab.h>
# include <linux/vmalloc.h>
# include <linux/string.h>
# ifdef CONFIG_XZ_DEC_X86
# define XZ_DEC_X86
# endif
# ifdef CONFIG_XZ_DEC_POWERPC
# define XZ_DEC_POWERPC
# endif
# ifdef CONFIG_XZ_DEC_IA64
# define XZ_DEC_IA64
# endif
# ifdef CONFIG_XZ_DEC_ARM
# define XZ_DEC_ARM
# endif
# ifdef CONFIG_XZ_DEC_ARMTHUMB
# define XZ_DEC_ARMTHUMB
# endif
# ifdef CONFIG_XZ_DEC_SPARC
# define XZ_DEC_SPARC
# endif
# define memeq(a, b, size) (memcmp(a, b, size) == 0)
# define memzero(buf, size) memset(buf, 0, size)
# endif
# define get_le32(p) le32_to_cpup((const uint32_t *)(p))
#else
/*
* For userspace builds, use a separate header to define the required
* macros and functions. This makes it easier to adapt the code into
* different environments and avoids clutter in the Linux kernel tree.
*/
# include "xz_config.h"
#endif
/* If no specific decoding mode is requested, enable support for all modes. */
#if !defined(XZ_DEC_SINGLE) && !defined(XZ_DEC_PREALLOC) \
&& !defined(XZ_DEC_DYNALLOC)
# define XZ_DEC_SINGLE
# define XZ_DEC_PREALLOC
# define XZ_DEC_DYNALLOC
#endif
/*
* The DEC_IS_foo(mode) macros are used in "if" statements. If only some
* of the supported modes are enabled, these macros will evaluate to true or
* false at compile time and thus allow the compiler to omit unneeded code.
*/
#ifdef XZ_DEC_SINGLE
# define DEC_IS_SINGLE(mode) ((mode) == XZ_SINGLE)
#else
# define DEC_IS_SINGLE(mode) (false)
#endif
#ifdef XZ_DEC_PREALLOC
# define DEC_IS_PREALLOC(mode) ((mode) == XZ_PREALLOC)
#else
# define DEC_IS_PREALLOC(mode) (false)
#endif
#ifdef XZ_DEC_DYNALLOC
# define DEC_IS_DYNALLOC(mode) ((mode) == XZ_DYNALLOC)
#else
# define DEC_IS_DYNALLOC(mode) (false)
#endif
#if !defined(XZ_DEC_SINGLE)
# define DEC_IS_MULTI(mode) (true)
#elif defined(XZ_DEC_PREALLOC) || defined(XZ_DEC_DYNALLOC)
# define DEC_IS_MULTI(mode) ((mode) != XZ_SINGLE)
#else
# define DEC_IS_MULTI(mode) (false)
#endif
/*
* If any of the BCJ filter decoders are wanted, define XZ_DEC_BCJ.
* XZ_DEC_BCJ is used to enable generic support for BCJ decoders.
*/
#ifndef XZ_DEC_BCJ
# if defined(XZ_DEC_X86) || defined(XZ_DEC_POWERPC) \
|| defined(XZ_DEC_IA64) || defined(XZ_DEC_ARM) \
|| defined(XZ_DEC_ARM) || defined(XZ_DEC_ARMTHUMB) \
|| defined(XZ_DEC_SPARC)
# define XZ_DEC_BCJ
# endif
#endif
/*
* Allocate memory for LZMA2 decoder. xz_dec_lzma2_reset() must be used
* before calling xz_dec_lzma2_run().
*/
XZ_EXTERN struct xz_dec_lzma2 *xz_dec_lzma2_create(enum xz_mode mode,
uint32_t dict_max);
/*
* Decode the LZMA2 properties (one byte) and reset the decoder. Return
* XZ_OK on success, XZ_MEMLIMIT_ERROR if the preallocated dictionary is not
* big enough, and XZ_OPTIONS_ERROR if props indicates something that this
* decoder doesn't support.
*/
XZ_EXTERN enum xz_ret xz_dec_lzma2_reset(struct xz_dec_lzma2 *s,
uint8_t props);
/* Decode raw LZMA2 stream from b->in to b->out. */
XZ_EXTERN enum xz_ret xz_dec_lzma2_run(struct xz_dec_lzma2 *s,
struct xz_buf *b);
/* Free the memory allocated for the LZMA2 decoder. */
XZ_EXTERN void xz_dec_lzma2_end(struct xz_dec_lzma2 *s);
#ifdef XZ_DEC_BCJ
/*
* Allocate memory for BCJ decoders. xz_dec_bcj_reset() must be used before
* calling xz_dec_bcj_run().
*/
XZ_EXTERN struct xz_dec_bcj *xz_dec_bcj_create(bool single_call);
/*
* Decode the Filter ID of a BCJ filter. This implementation doesn't
* support custom start offsets, so no decoding of Filter Properties
* is needed. Returns XZ_OK if the given Filter ID is supported.
* Otherwise XZ_OPTIONS_ERROR is returned.
*/
XZ_EXTERN enum xz_ret xz_dec_bcj_reset(struct xz_dec_bcj *s, uint8_t id);
/*
* Decode raw BCJ + LZMA2 stream. This must be used only if there actually is
* a BCJ filter in the chain. If the chain has only LZMA2, xz_dec_lzma2_run()
* must be called directly.
*/
XZ_EXTERN enum xz_ret xz_dec_bcj_run(struct xz_dec_bcj *s,
struct xz_dec_lzma2 *lzma2,
struct xz_buf *b);
/* Free the memory allocated for the BCJ filters. */
#define xz_dec_bcj_end(s) kfree(s)
#endif
#endif

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/*
* Definitions for handling the .xz file format
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#ifndef XZ_STREAM_H
#define XZ_STREAM_H
#if defined(__KERNEL__) && !XZ_INTERNAL_CRC32
# include <linux/crc32.h>
# undef crc32
# define xz_crc32(buf, size, crc) \
(~crc32_le(~(uint32_t)(crc), buf, size))
#endif
/*
* See the .xz file format specification at
* http://tukaani.org/xz/xz-file-format.txt
* to understand the container format.
*/
#define STREAM_HEADER_SIZE 12
#define HEADER_MAGIC "\3757zXZ"
#define HEADER_MAGIC_SIZE 6
#define FOOTER_MAGIC "YZ"
#define FOOTER_MAGIC_SIZE 2
/*
* Variable-length integer can hold a 63-bit unsigned integer or a special
* value indicating that the value is unknown.
*
* Experimental: vli_type can be defined to uint32_t to save a few bytes
* in code size (no effect on speed). Doing so limits the uncompressed and
* compressed size of the file to less than 256 MiB and may also weaken
* error detection slightly.
*/
typedef uint64_t vli_type;
#define VLI_MAX ((vli_type)-1 / 2)
#define VLI_UNKNOWN ((vli_type)-1)
/* Maximum encoded size of a VLI */
#define VLI_BYTES_MAX (sizeof(vli_type) * 8 / 7)
/* Integrity Check types */
enum xz_check {
XZ_CHECK_NONE = 0,
XZ_CHECK_CRC32 = 1,
XZ_CHECK_CRC64 = 4,
XZ_CHECK_SHA256 = 10
};
/* Maximum possible Check ID */
#define XZ_CHECK_MAX 15
#endif

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#!/bin/sh
#
# This is a wrapper for xz to compress the kernel image using appropriate
# compression options depending on the architecture.
#
# Author: Lasse Collin <lasse.collin@tukaani.org>
#
# This file has been put into the public domain.
# You can do whatever you want with this file.
#
BCJ=
LZMA2OPTS=
case $ARCH in
x86|x86_64) BCJ=--x86 ;;
powerpc) BCJ=--powerpc ;;
ia64) BCJ=--ia64; LZMA2OPTS=pb=4 ;;
arm) BCJ=--arm ;;
sparc) BCJ=--sparc ;;
esac
exec xz --check=crc32 $BCJ --lzma2=$LZMA2OPTS,dict=32MiB

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#
# Makefile
#
# Author: Lasse Collin <lasse.collin@tukaani.org>
#
# This file has been put into the public domain.
# You can do whatever you want with this file.
#
CC = gcc -std=gnu89
BCJ_CPPFLAGS = -DXZ_DEC_X86 -DXZ_DEC_POWERPC -DXZ_DEC_IA64 \
-DXZ_DEC_ARM -DXZ_DEC_ARMTHUMB -DXZ_DEC_SPARC
CPPFLAGS = -DXZ_DEC_ANY_CHECK
CFLAGS = -ggdb3 -O2 -pedantic -Wall -Wextra
RM = rm -f
VPATH = ../linux/include/linux ../linux/lib/xz
COMMON_SRCS = xz_crc32.c xz_dec_stream.c xz_dec_lzma2.c xz_dec_bcj.c
COMMON_OBJS = $(COMMON_SRCS:.c=.o)
XZMINIDEC_OBJS = xzminidec.o
BYTETEST_OBJS = bytetest.o
BUFTEST_OBJS = buftest.o
BOOTTEST_OBJS = boottest.o
XZ_HEADERS = xz.h xz_private.h xz_stream.h xz_lzma2.h xz_config.h
PROGRAMS = xzminidec bytetest buftest boottest
ALL_CPPFLAGS = -I../linux/include/linux -I. $(BCJ_CPPFLAGS) $(CPPFLAGS)
all: $(PROGRAMS)
%.o: %.c $(XZ_HEADERS)
$(CC) $(ALL_CPPFLAGS) $(CFLAGS) -c -o $@ $<
xzminidec: $(COMMON_OBJS) $(XZMINIDEC_OBJS)
$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(COMMON_OBJS) $(XZMINIDEC_OBJS)
bytetest: $(COMMON_OBJS) $(BYTETEST_OBJS)
$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(COMMON_OBJS) $(BYTETEST_OBJS)
buftest: $(COMMON_OBJS) $(BUFTEST_OBJS)
$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $(COMMON_OBJS) $(BUFTEST_OBJS)
boottest: $(BOOTTEST_OBJS) $(COMMON_SRCS)
$(CC) $(ALL_CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o $@ $(BOOTTEST_OBJS)
.PHONY: clean
clean:
-$(RM) $(COMMON_OBJS) $(XZMINIDEC_OBJS) $(BUFTEST_OBJS) \
$(BOOTTEST_OBJS) $(PROGRAMS)

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/*
* Test application for xz_boot.c
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#define STATIC static
#define INIT
static void error(/*const*/ char *msg)
{
fprintf(stderr, "%s\n", msg);
}
#include "../linux/lib/decompress_unxz.c"
static uint8_t in[1024 * 1024];
static uint8_t out[1024 * 1024];
static int fill(void *buf, unsigned int size)
{
return fread(buf, 1, size, stdin);
}
static int flush(/*const*/ void *buf, unsigned int size)
{
return fwrite(buf, 1, size, stdout);
}
static void test_buf_to_buf(void)
{
size_t in_size;
int ret;
in_size = fread(in, 1, sizeof(in), stdin);
ret = decompress(in, in_size, NULL, NULL, out, NULL, &error);
/* fwrite(out, 1, FIXME, stdout); */
fprintf(stderr, "ret = %d\n", ret);
}
static void test_buf_to_cb(void)
{
size_t in_size;
int in_used;
int ret;
in_size = fread(in, 1, sizeof(in), stdin);
ret = decompress(in, in_size, NULL, &flush, NULL, &in_used, &error);
fprintf(stderr, "ret = %d; in_used = %d\n", ret, in_used);
}
static void test_cb_to_cb(void)
{
int ret;
ret = decompress(NULL, 0, &fill, &flush, NULL, NULL, &error);
fprintf(stderr, "ret = %d\n", ret);
}
/*
* Not used by Linux <= 2.6.37-rc4 and newer probably won't use it either,
* but this kind of use case is still required to be supported by the API.
*/
static void test_cb_to_buf(void)
{
int in_used;
int ret;
ret = decompress(in, 0, &fill, NULL, out, &in_used, &error);
/* fwrite(out, 1, FIXME, stdout); */
fprintf(stderr, "ret = %d; in_used = %d\n", ret, in_used);
}
int main(int argc, char **argv)
{
if (argc != 2)
fprintf(stderr, "Usage: %s [bb|bc|cc|cb]\n", argv[0]);
else if (strcmp(argv[1], "bb") == 0)
test_buf_to_buf();
else if (strcmp(argv[1], "bc") == 0)
test_buf_to_cb();
else if (strcmp(argv[1], "cc") == 0)
test_cb_to_cb();
else if (strcmp(argv[1], "cb") == 0)
test_cb_to_buf();
else
fprintf(stderr, "Usage: %s [bb|bc|cc|cb]\n", argv[0]);
return 0;
}

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@ -0,0 +1,48 @@
/*
* Test application to test buffer-to-buffer decoding
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include "xz.h"
#define BUFFER_SIZE (1024 * 1024)
static uint8_t in[BUFFER_SIZE];
static uint8_t out[BUFFER_SIZE];
int main(void)
{
struct xz_buf b;
struct xz_dec *s;
enum xz_ret ret;
xz_crc32_init();
s = xz_dec_init(XZ_SINGLE, 0);
if (s == NULL) {
fputs("Initialization failed", stderr);
return 1;
}
b.in = in;
b.in_pos = 0;
b.in_size = fread(in, 1, sizeof(in), stdin);
b.out = out;
b.out_pos = 0;
b.out_size = sizeof(out);
ret = xz_dec_run(s, &b);
xz_dec_end(s);
fwrite(out, 1, b.out_pos, stdout);
fprintf(stderr, "%d\n", ret);
return 0;
}

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/*
* Private includes and definitions for userspace use of XZ Embedded
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
#ifndef XZ_CONFIG_H
#define XZ_CONFIG_H
/* Uncomment as needed to enable BCJ filter decoders. */
/* #define XZ_DEC_X86 */
/* #define XZ_DEC_POWERPC */
/* #define XZ_DEC_IA64 */
/* #define XZ_DEC_ARM */
/* #define XZ_DEC_ARMTHUMB */
/* #define XZ_DEC_SPARC */
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include "xz.h"
#define kmalloc(size, flags) malloc(size)
#define kfree(ptr) free(ptr)
#define vmalloc(size) malloc(size)
#define vfree(ptr) free(ptr)
#define memeq(a, b, size) (memcmp(a, b, size) == 0)
#define memzero(buf, size) memset(buf, 0, size)
#ifndef min
# define min(x, y) ((x) < (y) ? (x) : (y))
#endif
#define min_t(type, x, y) min(x, y)
/*
* Some functions have been marked with __always_inline to keep the
* performance reasonable even when the compiler is optimizing for
* small code size. You may be able to save a few bytes by #defining
* __always_inline to plain inline, but don't complain if the code
* becomes slow.
*
* NOTE: System headers on GNU/Linux may #define this macro already,
* so if you want to change it, you need to #undef it first.
*/
#ifndef __always_inline
# ifdef __GNUC__
# define __always_inline \
inline __attribute__((__always_inline__))
# else
# define __always_inline inline
# endif
#endif
/* Inline functions to access unaligned unsigned 32-bit integers */
#ifndef get_unaligned_le32
static inline uint32_t get_unaligned_le32(const uint8_t *buf)
{
return (uint32_t)buf[0]
| ((uint32_t)buf[1] << 8)
| ((uint32_t)buf[2] << 16)
| ((uint32_t)buf[3] << 24);
}
#endif
#ifndef get_unaligned_be32
static inline uint32_t get_unaligned_be32(const uint8_t *buf)
{
return (uint32_t)(buf[0] << 24)
| ((uint32_t)buf[1] << 16)
| ((uint32_t)buf[2] << 8)
| (uint32_t)buf[3];
}
#endif
#ifndef put_unaligned_le32
static inline void put_unaligned_le32(uint32_t val, uint8_t *buf)
{
buf[0] = (uint8_t)val;
buf[1] = (uint8_t)(val >> 8);
buf[2] = (uint8_t)(val >> 16);
buf[3] = (uint8_t)(val >> 24);
}
#endif
#ifndef put_unaligned_be32
static inline void put_unaligned_be32(uint32_t val, uint8_t *buf)
{
buf[0] = (uint8_t)(val >> 24);
buf[1] = (uint8_t)(val >> 16);
buf[2] = (uint8_t)(val >> 8);
buf[3] = (uint8_t)val;
}
#endif
/*
* Use get_unaligned_le32() also for aligned access for simplicity. On
* little endian systems, #define get_le32(ptr) (*(const uint32_t *)(ptr))
* could save a few bytes in code size.
*/
#ifndef get_le32
# define get_le32 get_unaligned_le32
#endif
#endif

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@ -0,0 +1,132 @@
/*
* Simple XZ decoder command line tool
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/
/*
* This is really limited: Not all filters from .xz format are supported,
* only CRC32 is supported as the integrity check, and decoding of
* concatenated .xz streams is not supported. Thus, you may want to look
* at xzdec from XZ Utils if a few KiB bigger tool is not a problem.
*/
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include "xz.h"
static uint8_t in[BUFSIZ];
static uint8_t out[BUFSIZ];
int main(int argc, char **argv)
{
struct xz_buf b;
struct xz_dec *s;
enum xz_ret ret;
const char *msg;
if (argc >= 2 && strcmp(argv[1], "--help") == 0) {
fputs("Uncompress a .xz file from stdin to stdout.\n"
"Arguments other than `--help' are ignored.\n",
stdout);
return 0;
}
xz_crc32_init();
/*
* Support up to 64 MiB dictionary. The actually needed memory
* is allocated once the headers have been parsed.
*/
s = xz_dec_init(XZ_DYNALLOC, 1 << 26);
if (s == NULL) {
msg = "Memory allocation failed\n";
goto error;
}
b.in = in;
b.in_pos = 0;
b.in_size = 0;
b.out = out;
b.out_pos = 0;
b.out_size = BUFSIZ;
while (true) {
if (b.in_pos == b.in_size) {
b.in_size = fread(in, 1, sizeof(in), stdin);
b.in_pos = 0;
}
ret = xz_dec_run(s, &b);
if (b.out_pos == sizeof(out)) {
if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos) {
msg = "Write error\n";
goto error;
}
b.out_pos = 0;
}
if (ret == XZ_OK)
continue;
#ifdef XZ_DEC_ANY_CHECK
if (ret == XZ_UNSUPPORTED_CHECK) {
fputs(argv[0], stderr);
fputs(": ", stderr);
fputs("Unsupported check; not verifying "
"file integrity\n", stderr);
continue;
}
#endif
if (fwrite(out, 1, b.out_pos, stdout) != b.out_pos
|| fclose(stdout)) {
msg = "Write error\n";
goto error;
}
switch (ret) {
case XZ_STREAM_END:
xz_dec_end(s);
return 0;
case XZ_MEM_ERROR:
msg = "Memory allocation failed\n";
goto error;
case XZ_MEMLIMIT_ERROR:
msg = "Memory usage limit reached\n";
goto error;
case XZ_FORMAT_ERROR:
msg = "Not a .xz file\n";
goto error;
case XZ_OPTIONS_ERROR:
msg = "Unsupported options in the .xz headers\n";
goto error;
case XZ_DATA_ERROR:
case XZ_BUF_ERROR:
msg = "File is corrupt\n";
goto error;
default:
msg = "Bug!\n";
goto error;
}
}
error:
xz_dec_end(s);
fputs(argv[0], stderr);
fputs(": ", stderr);
fputs(msg, stderr);
return 1;
}