1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * uncompress.c
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * (C) Copyright 1999 Linus Torvalds
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * cramfs interfaces to the uncompression library. There's really just
8*4882a593Smuzhiyun * three entrypoints:
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * - cramfs_uncompress_init() - called to initialize the thing.
11*4882a593Smuzhiyun * - cramfs_uncompress_exit() - tell me when you're done
12*4882a593Smuzhiyun * - cramfs_uncompress_block() - uncompress a block.
13*4882a593Smuzhiyun *
14*4882a593Smuzhiyun * NOTE NOTE NOTE! The uncompression is entirely single-threaded. We
15*4882a593Smuzhiyun * only have one stream, and we'll initialize it only once even if it
16*4882a593Smuzhiyun * then is used by multiple filesystems.
17*4882a593Smuzhiyun */
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun #include <linux/kernel.h>
22*4882a593Smuzhiyun #include <linux/errno.h>
23*4882a593Smuzhiyun #include <linux/vmalloc.h>
24*4882a593Smuzhiyun #include <linux/zlib.h>
25*4882a593Smuzhiyun #include "internal.h"
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun static z_stream stream;
28*4882a593Smuzhiyun static int initialized;
29*4882a593Smuzhiyun
30*4882a593Smuzhiyun /* Returns length of decompressed data. */
cramfs_uncompress_block(void * dst,int dstlen,void * src,int srclen)31*4882a593Smuzhiyun int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun int err;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun stream.next_in = src;
36*4882a593Smuzhiyun stream.avail_in = srclen;
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun stream.next_out = dst;
39*4882a593Smuzhiyun stream.avail_out = dstlen;
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun err = zlib_inflateReset(&stream);
42*4882a593Smuzhiyun if (err != Z_OK) {
43*4882a593Smuzhiyun pr_err("zlib_inflateReset error %d\n", err);
44*4882a593Smuzhiyun zlib_inflateEnd(&stream);
45*4882a593Smuzhiyun zlib_inflateInit(&stream);
46*4882a593Smuzhiyun }
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun err = zlib_inflate(&stream, Z_FINISH);
49*4882a593Smuzhiyun if (err != Z_STREAM_END)
50*4882a593Smuzhiyun goto err;
51*4882a593Smuzhiyun return stream.total_out;
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun err:
54*4882a593Smuzhiyun pr_err("Error %d while decompressing!\n", err);
55*4882a593Smuzhiyun pr_err("%p(%d)->%p(%d)\n", src, srclen, dst, dstlen);
56*4882a593Smuzhiyun return -EIO;
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun
cramfs_uncompress_init(void)59*4882a593Smuzhiyun int cramfs_uncompress_init(void)
60*4882a593Smuzhiyun {
61*4882a593Smuzhiyun if (!initialized++) {
62*4882a593Smuzhiyun stream.workspace = vmalloc(zlib_inflate_workspacesize());
63*4882a593Smuzhiyun if (!stream.workspace) {
64*4882a593Smuzhiyun initialized = 0;
65*4882a593Smuzhiyun return -ENOMEM;
66*4882a593Smuzhiyun }
67*4882a593Smuzhiyun stream.next_in = NULL;
68*4882a593Smuzhiyun stream.avail_in = 0;
69*4882a593Smuzhiyun zlib_inflateInit(&stream);
70*4882a593Smuzhiyun }
71*4882a593Smuzhiyun return 0;
72*4882a593Smuzhiyun }
73*4882a593Smuzhiyun
cramfs_uncompress_exit(void)74*4882a593Smuzhiyun void cramfs_uncompress_exit(void)
75*4882a593Smuzhiyun {
76*4882a593Smuzhiyun if (!--initialized) {
77*4882a593Smuzhiyun zlib_inflateEnd(&stream);
78*4882a593Smuzhiyun vfree(stream.workspace);
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun }
81