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