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