252 lines
6.6 KiB
C
252 lines
6.6 KiB
C
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/*
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* This file is part of UBIFS.
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*
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* Copyright (C) 2006-2008 Nokia Corporation.
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* Copyright (C) 2006, 2007 University of Szeged, Hungary
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Authors: Adrian Hunter
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* Artem Bityutskiy (Битюцкий Артём)
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* Zoltan Sogor
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*/
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/*
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* This file provides a single place to access to compression and
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* decompression.
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*/
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#include <linux/crypto.h>
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#include "ubifs.h"
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/* Fake description object for the "none" compressor */
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static struct ubifs_compressor none_compr = {
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.compr_type = UBIFS_COMPR_NONE,
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.name = "no compression",
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.capi_name = "",
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};
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#ifdef CONFIG_UBIFS_FS_LZO
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static DEFINE_MUTEX(lzo_mutex);
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static struct ubifs_compressor lzo_compr = {
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.compr_type = UBIFS_COMPR_LZO,
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.comp_mutex = &lzo_mutex,
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.name = "LZO",
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.capi_name = "lzo",
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};
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#else
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static struct ubifs_compressor lzo_compr = {
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.compr_type = UBIFS_COMPR_LZO,
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.name = "LZO",
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};
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#endif
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#ifdef CONFIG_UBIFS_FS_ZLIB
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static DEFINE_MUTEX(deflate_mutex);
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static DEFINE_MUTEX(inflate_mutex);
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static struct ubifs_compressor zlib_compr = {
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.compr_type = UBIFS_COMPR_ZLIB,
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.comp_mutex = &deflate_mutex,
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.decomp_mutex = &inflate_mutex,
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.name = "zlib",
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.capi_name = "deflate",
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};
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#else
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static struct ubifs_compressor zlib_compr = {
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.compr_type = UBIFS_COMPR_ZLIB,
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.name = "zlib",
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};
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#endif
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/* All UBIFS compressors */
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struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
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/**
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* ubifs_compress - compress data.
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* @in_buf: data to compress
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* @in_len: length of the data to compress
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* @out_buf: output buffer where compressed data should be stored
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* @out_len: output buffer length is returned here
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* @compr_type: type of compression to use on enter, actually used compression
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* type on exit
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*
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* This function compresses input buffer @in_buf of length @in_len and stores
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* the result in the output buffer @out_buf and the resulting length in
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* @out_len. If the input buffer does not compress, it is just copied to the
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* @out_buf. The same happens if @compr_type is %UBIFS_COMPR_NONE or if
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* compression error occurred.
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*
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* Note, if the input buffer was not compressed, it is copied to the output
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* buffer and %UBIFS_COMPR_NONE is returned in @compr_type.
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*/
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void ubifs_compress(const void *in_buf, int in_len, void *out_buf, int *out_len,
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int *compr_type)
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{
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int err;
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struct ubifs_compressor *compr = ubifs_compressors[*compr_type];
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if (*compr_type == UBIFS_COMPR_NONE)
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goto no_compr;
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/* If the input data is small, do not even try to compress it */
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if (in_len < UBIFS_MIN_COMPR_LEN)
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goto no_compr;
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if (compr->comp_mutex)
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mutex_lock(compr->comp_mutex);
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err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf,
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out_len);
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if (compr->comp_mutex)
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mutex_unlock(compr->comp_mutex);
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if (unlikely(err)) {
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ubifs_warn("cannot compress %d bytes, compressor %s, "
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"error %d, leave data uncompressed",
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in_len, compr->name, err);
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goto no_compr;
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}
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/*
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* Presently, we just require that compression results in less data,
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* rather than any defined minimum compression ratio or amount.
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*/
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if (ALIGN(*out_len, 8) >= ALIGN(in_len, 8))
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goto no_compr;
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return;
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no_compr:
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memcpy(out_buf, in_buf, in_len);
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*out_len = in_len;
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*compr_type = UBIFS_COMPR_NONE;
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}
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/**
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* ubifs_decompress - decompress data.
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* @in_buf: data to decompress
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* @in_len: length of the data to decompress
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* @out_buf: output buffer where decompressed data should
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* @out_len: output length is returned here
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* @compr_type: type of compression
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*
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* This function decompresses data from buffer @in_buf into buffer @out_buf.
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* The length of the uncompressed data is returned in @out_len. This functions
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* returns %0 on success or a negative error code on failure.
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*/
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int ubifs_decompress(const void *in_buf, int in_len, void *out_buf,
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int *out_len, int compr_type)
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{
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int err;
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struct ubifs_compressor *compr;
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if (unlikely(compr_type < 0 || compr_type >= UBIFS_COMPR_TYPES_CNT)) {
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ubifs_err("invalid compression type %d", compr_type);
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return -EINVAL;
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}
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compr = ubifs_compressors[compr_type];
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if (unlikely(!compr->capi_name)) {
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ubifs_err("%s compression is not compiled in", compr->name);
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return -EINVAL;
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}
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if (compr_type == UBIFS_COMPR_NONE) {
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memcpy(out_buf, in_buf, in_len);
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*out_len = in_len;
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return 0;
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}
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if (compr->decomp_mutex)
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mutex_lock(compr->decomp_mutex);
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err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf,
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out_len);
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if (compr->decomp_mutex)
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mutex_unlock(compr->decomp_mutex);
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if (err)
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ubifs_err("cannot decompress %d bytes, compressor %s, "
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"error %d", in_len, compr->name, err);
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return err;
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}
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/**
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* compr_init - initialize a compressor.
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* @compr: compressor description object
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*
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* This function initializes the requested compressor and returns zero in case
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* of success or a negative error code in case of failure.
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*/
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static int __init compr_init(struct ubifs_compressor *compr)
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{
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if (compr->capi_name) {
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compr->cc = crypto_alloc_comp(compr->capi_name, 0, 0);
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if (IS_ERR(compr->cc)) {
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ubifs_err("cannot initialize compressor %s, error %ld",
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compr->name, PTR_ERR(compr->cc));
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return PTR_ERR(compr->cc);
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}
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}
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ubifs_compressors[compr->compr_type] = compr;
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return 0;
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}
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/**
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* compr_exit - de-initialize a compressor.
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* @compr: compressor description object
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*/
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static void compr_exit(struct ubifs_compressor *compr)
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{
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if (compr->capi_name)
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crypto_free_comp(compr->cc);
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return;
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}
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/**
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* ubifs_compressors_init - initialize UBIFS compressors.
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*
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* This function initializes the compressor which were compiled in. Returns
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* zero in case of success and a negative error code in case of failure.
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*/
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int __init ubifs_compressors_init(void)
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{
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int err;
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err = compr_init(&lzo_compr);
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if (err)
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return err;
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err = compr_init(&zlib_compr);
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if (err)
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goto out_lzo;
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ubifs_compressors[UBIFS_COMPR_NONE] = &none_compr;
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return 0;
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out_lzo:
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compr_exit(&lzo_compr);
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return err;
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}
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/**
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* ubifs_compressors_exit - de-initialize UBIFS compressors.
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*/
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void __exit ubifs_compressors_exit(void)
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{
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compr_exit(&lzo_compr);
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compr_exit(&zlib_compr);
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}
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