147 строки
3.0 KiB
C
147 строки
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (c) 2013, 2014
|
|
* Phillip Lougher <phillip@squashfs.org.uk>
|
|
*/
|
|
|
|
#include <linux/bio.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/vmalloc.h>
|
|
#include <linux/lz4.h>
|
|
|
|
#include "squashfs_fs.h"
|
|
#include "squashfs_fs_sb.h"
|
|
#include "squashfs.h"
|
|
#include "decompressor.h"
|
|
#include "page_actor.h"
|
|
|
|
#define LZ4_LEGACY 1
|
|
|
|
struct lz4_comp_opts {
|
|
__le32 version;
|
|
__le32 flags;
|
|
};
|
|
|
|
struct squashfs_lz4 {
|
|
void *input;
|
|
void *output;
|
|
};
|
|
|
|
|
|
static void *lz4_comp_opts(struct squashfs_sb_info *msblk,
|
|
void *buff, int len)
|
|
{
|
|
struct lz4_comp_opts *comp_opts = buff;
|
|
|
|
/* LZ4 compressed filesystems always have compression options */
|
|
if (comp_opts == NULL || len < sizeof(*comp_opts))
|
|
return ERR_PTR(-EIO);
|
|
|
|
if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) {
|
|
/* LZ4 format currently used by the kernel is the 'legacy'
|
|
* format */
|
|
ERROR("Unknown LZ4 version\n");
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
|
|
static void *lz4_init(struct squashfs_sb_info *msblk, void *buff)
|
|
{
|
|
int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
|
|
struct squashfs_lz4 *stream;
|
|
|
|
stream = kzalloc(sizeof(*stream), GFP_KERNEL);
|
|
if (stream == NULL)
|
|
goto failed;
|
|
stream->input = vmalloc(block_size);
|
|
if (stream->input == NULL)
|
|
goto failed2;
|
|
stream->output = vmalloc(block_size);
|
|
if (stream->output == NULL)
|
|
goto failed3;
|
|
|
|
return stream;
|
|
|
|
failed3:
|
|
vfree(stream->input);
|
|
failed2:
|
|
kfree(stream);
|
|
failed:
|
|
ERROR("Failed to initialise LZ4 decompressor\n");
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
|
|
static void lz4_free(void *strm)
|
|
{
|
|
struct squashfs_lz4 *stream = strm;
|
|
|
|
if (stream) {
|
|
vfree(stream->input);
|
|
vfree(stream->output);
|
|
}
|
|
kfree(stream);
|
|
}
|
|
|
|
|
|
static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,
|
|
struct bio *bio, int offset, int length,
|
|
struct squashfs_page_actor *output)
|
|
{
|
|
struct bvec_iter_all iter_all = {};
|
|
struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
|
|
struct squashfs_lz4 *stream = strm;
|
|
void *buff = stream->input, *data;
|
|
int bytes = length, res;
|
|
|
|
while (bio_next_segment(bio, &iter_all)) {
|
|
int avail = min(bytes, ((int)bvec->bv_len) - offset);
|
|
|
|
data = bvec_virt(bvec);
|
|
memcpy(buff, data + offset, avail);
|
|
buff += avail;
|
|
bytes -= avail;
|
|
offset = 0;
|
|
}
|
|
|
|
res = LZ4_decompress_safe(stream->input, stream->output,
|
|
length, output->length);
|
|
|
|
if (res < 0)
|
|
return -EIO;
|
|
|
|
bytes = res;
|
|
data = squashfs_first_page(output);
|
|
buff = stream->output;
|
|
while (data) {
|
|
if (bytes <= PAGE_SIZE) {
|
|
if (!IS_ERR(data))
|
|
memcpy(data, buff, bytes);
|
|
break;
|
|
}
|
|
if (!IS_ERR(data))
|
|
memcpy(data, buff, PAGE_SIZE);
|
|
buff += PAGE_SIZE;
|
|
bytes -= PAGE_SIZE;
|
|
data = squashfs_next_page(output);
|
|
}
|
|
squashfs_finish_page(output);
|
|
|
|
return res;
|
|
}
|
|
|
|
const struct squashfs_decompressor squashfs_lz4_comp_ops = {
|
|
.init = lz4_init,
|
|
.comp_opts = lz4_comp_opts,
|
|
.free = lz4_free,
|
|
.decompress = lz4_uncompress,
|
|
.id = LZ4_COMPRESSION,
|
|
.name = "lz4",
|
|
.alloc_buffer = 0,
|
|
.supported = 1
|
|
};
|