1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Squashfs - a compressed read only filesystem for Linux
5 * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
6 * Phillip Lougher <phillip@squashfs.org.uk>
12 #include <linux/mutex.h>
13 #include <linux/buffer_head.h>
14 #include <linux/slab.h>
16 #include <linux/bitops.h>
18 #include "squashfs_fs.h"
19 #include "squashfs_fs_sb.h"
21 #include "decompressor.h"
22 #include "page_actor.h"
29 struct disk_comp_opts {
30 __le32 dictionary_size;
38 static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk,
41 struct disk_comp_opts *comp_opts = buff;
42 struct comp_opts *opts;
45 opts = kmalloc(sizeof(*opts), GFP_KERNEL);
52 /* check compressor options are the expected length */
53 if (len < sizeof(*comp_opts)) {
58 opts->dict_size = le32_to_cpu(comp_opts->dictionary_size);
60 /* the dictionary size should be 2^n or 2^n+2^(n+1) */
61 n = ffs(opts->dict_size) - 1;
62 if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) +
69 opts->dict_size = max_t(int, msblk->block_size,
70 SQUASHFS_METADATA_SIZE);
81 static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff)
83 struct comp_opts *comp_opts = buff;
84 struct squashfs_xz *stream;
87 stream = kmalloc(sizeof(*stream), GFP_KERNEL);
93 stream->state = xz_dec_init(XZ_PREALLOC, comp_opts->dict_size);
94 if (stream->state == NULL) {
103 ERROR("Failed to initialise xz decompressor\n");
108 static void squashfs_xz_free(void *strm)
110 struct squashfs_xz *stream = strm;
113 xz_dec_end(stream->state);
119 static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
120 struct buffer_head **bh, int b, int offset, int length,
121 struct squashfs_page_actor *output)
124 int avail, total = 0, k = 0;
125 struct squashfs_xz *stream = strm;
127 xz_dec_reset(stream->state);
128 stream->buf.in_pos = 0;
129 stream->buf.in_size = 0;
130 stream->buf.out_pos = 0;
131 stream->buf.out_size = PAGE_SIZE;
132 stream->buf.out = squashfs_first_page(output);
135 if (stream->buf.in_pos == stream->buf.in_size && k < b) {
136 avail = min(length, msblk->devblksize - offset);
138 stream->buf.in = bh[k]->b_data + offset;
139 stream->buf.in_size = avail;
140 stream->buf.in_pos = 0;
144 if (stream->buf.out_pos == stream->buf.out_size) {
145 stream->buf.out = squashfs_next_page(output);
146 if (stream->buf.out != NULL) {
147 stream->buf.out_pos = 0;
152 xz_err = xz_dec_run(stream->state, &stream->buf);
154 if (stream->buf.in_pos == stream->buf.in_size && k < b)
156 } while (xz_err == XZ_OK);
158 squashfs_finish_page(output);
160 if (xz_err != XZ_STREAM_END || k < b)
163 return total + stream->buf.out_pos;
172 const struct squashfs_decompressor squashfs_xz_comp_ops = {
173 .init = squashfs_xz_init,
174 .comp_opts = squashfs_xz_comp_opts,
175 .free = squashfs_xz_free,
176 .decompress = squashfs_xz_uncompress,
177 .id = XZ_COMPRESSION,