1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Squashfs - a compressed read only filesystem for Linux
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
6*4882a593Smuzhiyun * Phillip Lougher <phillip@squashfs.org.uk>
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * zlib_wrapper.c
9*4882a593Smuzhiyun */
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #include <linux/mutex.h>
13*4882a593Smuzhiyun #include <linux/bio.h>
14*4882a593Smuzhiyun #include <linux/slab.h>
15*4882a593Smuzhiyun #include <linux/zlib.h>
16*4882a593Smuzhiyun #include <linux/vmalloc.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun #include "squashfs_fs.h"
19*4882a593Smuzhiyun #include "squashfs_fs_sb.h"
20*4882a593Smuzhiyun #include "squashfs.h"
21*4882a593Smuzhiyun #include "decompressor.h"
22*4882a593Smuzhiyun #include "page_actor.h"
23*4882a593Smuzhiyun
zlib_init(struct squashfs_sb_info * dummy,void * buff)24*4882a593Smuzhiyun static void *zlib_init(struct squashfs_sb_info *dummy, void *buff)
25*4882a593Smuzhiyun {
26*4882a593Smuzhiyun z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
27*4882a593Smuzhiyun if (stream == NULL)
28*4882a593Smuzhiyun goto failed;
29*4882a593Smuzhiyun stream->workspace = vmalloc(zlib_inflate_workspacesize());
30*4882a593Smuzhiyun if (stream->workspace == NULL)
31*4882a593Smuzhiyun goto failed;
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun return stream;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun failed:
36*4882a593Smuzhiyun ERROR("Failed to allocate zlib workspace\n");
37*4882a593Smuzhiyun kfree(stream);
38*4882a593Smuzhiyun return ERR_PTR(-ENOMEM);
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun
zlib_free(void * strm)42*4882a593Smuzhiyun static void zlib_free(void *strm)
43*4882a593Smuzhiyun {
44*4882a593Smuzhiyun z_stream *stream = strm;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun if (stream)
47*4882a593Smuzhiyun vfree(stream->workspace);
48*4882a593Smuzhiyun kfree(stream);
49*4882a593Smuzhiyun }
50*4882a593Smuzhiyun
51*4882a593Smuzhiyun
zlib_uncompress(struct squashfs_sb_info * msblk,void * strm,struct bio * bio,int offset,int length,struct squashfs_page_actor * output)52*4882a593Smuzhiyun static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
53*4882a593Smuzhiyun struct bio *bio, int offset, int length,
54*4882a593Smuzhiyun struct squashfs_page_actor *output)
55*4882a593Smuzhiyun {
56*4882a593Smuzhiyun struct bvec_iter_all iter_all = {};
57*4882a593Smuzhiyun struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
58*4882a593Smuzhiyun int zlib_init = 0, error = 0;
59*4882a593Smuzhiyun z_stream *stream = strm;
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun stream->avail_out = PAGE_SIZE;
62*4882a593Smuzhiyun stream->next_out = squashfs_first_page(output);
63*4882a593Smuzhiyun stream->avail_in = 0;
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun for (;;) {
66*4882a593Smuzhiyun int zlib_err;
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun if (stream->avail_in == 0) {
69*4882a593Smuzhiyun const void *data;
70*4882a593Smuzhiyun int avail;
71*4882a593Smuzhiyun
72*4882a593Smuzhiyun if (!bio_next_segment(bio, &iter_all)) {
73*4882a593Smuzhiyun /* Z_STREAM_END must be reached. */
74*4882a593Smuzhiyun error = -EIO;
75*4882a593Smuzhiyun break;
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun avail = min(length, ((int)bvec->bv_len) - offset);
79*4882a593Smuzhiyun data = page_address(bvec->bv_page) + bvec->bv_offset;
80*4882a593Smuzhiyun length -= avail;
81*4882a593Smuzhiyun stream->next_in = data + offset;
82*4882a593Smuzhiyun stream->avail_in = avail;
83*4882a593Smuzhiyun offset = 0;
84*4882a593Smuzhiyun }
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun if (stream->avail_out == 0) {
87*4882a593Smuzhiyun stream->next_out = squashfs_next_page(output);
88*4882a593Smuzhiyun if (stream->next_out != NULL)
89*4882a593Smuzhiyun stream->avail_out = PAGE_SIZE;
90*4882a593Smuzhiyun }
91*4882a593Smuzhiyun
92*4882a593Smuzhiyun if (!zlib_init) {
93*4882a593Smuzhiyun zlib_err = zlib_inflateInit(stream);
94*4882a593Smuzhiyun if (zlib_err != Z_OK) {
95*4882a593Smuzhiyun error = -EIO;
96*4882a593Smuzhiyun break;
97*4882a593Smuzhiyun }
98*4882a593Smuzhiyun zlib_init = 1;
99*4882a593Smuzhiyun }
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
102*4882a593Smuzhiyun if (zlib_err == Z_STREAM_END)
103*4882a593Smuzhiyun break;
104*4882a593Smuzhiyun if (zlib_err != Z_OK) {
105*4882a593Smuzhiyun error = -EIO;
106*4882a593Smuzhiyun break;
107*4882a593Smuzhiyun }
108*4882a593Smuzhiyun }
109*4882a593Smuzhiyun
110*4882a593Smuzhiyun squashfs_finish_page(output);
111*4882a593Smuzhiyun
112*4882a593Smuzhiyun if (!error)
113*4882a593Smuzhiyun if (zlib_inflateEnd(stream) != Z_OK)
114*4882a593Smuzhiyun error = -EIO;
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun return error ? error : stream->total_out;
117*4882a593Smuzhiyun }
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun const struct squashfs_decompressor squashfs_zlib_comp_ops = {
120*4882a593Smuzhiyun .init = zlib_init,
121*4882a593Smuzhiyun .free = zlib_free,
122*4882a593Smuzhiyun .decompress = zlib_uncompress,
123*4882a593Smuzhiyun .id = ZLIB_COMPRESSION,
124*4882a593Smuzhiyun .name = "zlib",
125*4882a593Smuzhiyun .supported = 1
126*4882a593Smuzhiyun };
127*4882a593Smuzhiyun
128