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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
* Phillip Lougher <phillip@squashfs.org.uk>
*
* xz_wrapper.c
*/
#include <linux/mutex.h>
#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/xz.h>
#include <linux/bitops.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
#include "page_actor.h"
struct squashfs_xz {
struct xz_dec *state;
struct xz_buf buf;
};
struct disk_comp_opts {
__le32 dictionary_size;
__le32 flags;
};
struct comp_opts {
int dict_size;
};
static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk,
void *buff, int len)
{
struct disk_comp_opts *comp_opts = buff;
struct comp_opts *opts;
int err = 0, n;
opts = kmalloc(sizeof(*opts), GFP_KERNEL);
if (opts == NULL) {
err = -ENOMEM;
goto out2;
}
if (comp_opts) {
/* check compressor options are the expected length */
if (len < sizeof(*comp_opts)) {
err = -EIO;
goto out;
}
opts->dict_size = le32_to_cpu(comp_opts->dictionary_size);
/* the dictionary size should be 2^n or 2^n+2^(n+1) */
n = ffs(opts->dict_size) - 1;
if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) +
(1 << (n + 1))) {
err = -EIO;
goto out;
}
} else
/* use defaults */
opts->dict_size = max_t(int, msblk->block_size,
SQUASHFS_METADATA_SIZE);
return opts;
out:
kfree(opts);
out2:
return ERR_PTR(err);
}
static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff)
{
struct comp_opts *comp_opts = buff;
struct squashfs_xz *stream;
int err;
stream = kmalloc(sizeof(*stream), GFP_KERNEL);
if (stream == NULL) {
err = -ENOMEM;
goto failed;
}
stream->state = xz_dec_init(XZ_PREALLOC, comp_opts->dict_size);
if (stream->state == NULL) {
kfree(stream);
err = -ENOMEM;
goto failed;
}
return stream;
failed:
ERROR("Failed to initialise xz decompressor\n");
return ERR_PTR(err);
}
static void squashfs_xz_free(void *strm)
{
struct squashfs_xz *stream = strm;
if (stream) {
xz_dec_end(stream->state);
kfree(stream);
}
}
static int squashfs_xz_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);
int total = 0, error = 0;
struct squashfs_xz *stream = strm;
xz_dec_reset(stream->state);
stream->buf.in_pos = 0;
stream->buf.in_size = 0;
stream->buf.out_pos = 0;
stream->buf.out_size = PAGE_SIZE;
stream->buf.out = squashfs_first_page(output);
for (;;) {
enum xz_ret xz_err;
if (stream->buf.in_pos == stream->buf.in_size) {
const void *data;
int avail;
if (!bio_next_segment(bio, &iter_all)) {
/* XZ_STREAM_END must be reached. */
error = -EIO;
break;
}
avail = min(length, ((int)bvec->bv_len) - offset);
data = page_address(bvec->bv_page) + bvec->bv_offset;
length -= avail;
stream->buf.in = data + offset;
stream->buf.in_size = avail;
stream->buf.in_pos = 0;
offset = 0;
}
if (stream->buf.out_pos == stream->buf.out_size) {
stream->buf.out = squashfs_next_page(output);
if (stream->buf.out != NULL) {
stream->buf.out_pos = 0;
total += PAGE_SIZE;
}
}
xz_err = xz_dec_run(stream->state, &stream->buf);
if (xz_err == XZ_STREAM_END)
break;
if (xz_err != XZ_OK) {
error = -EIO;
break;
}
}
squashfs_finish_page(output);
return error ? error : total + stream->buf.out_pos;
}
const struct squashfs_decompressor squashfs_xz_comp_ops = {
.init = squashfs_xz_init,
.comp_opts = squashfs_xz_comp_opts,
.free = squashfs_xz_free,
.decompress = squashfs_xz_uncompress,
.id = XZ_COMPRESSION,
.name = "xz",
.supported = 1
};
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