File: compr_zlib.c

package info (click to toggle)
linux 3.16.7-ckt2-1
  • links: PTS, VCS
  • area: main
  • in suites: jessie
  • size: 734,120 kB
  • ctags: 2,369,605
  • sloc: ansic: 12,212,866; asm: 277,256; perl: 53,999; xml: 47,771; makefile: 30,481; sh: 8,035; python: 6,583; cpp: 5,121; yacc: 4,254; lex: 2,215; awk: 741; pascal: 231; lisp: 218; sed: 30
file content (221 lines) | stat: -rw-r--r-- 5,619 bytes parent folder | download | duplicates (15)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#if !defined(__KERNEL__) && !defined(__ECOS)
#error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
#endif

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/zlib.h>
#include <linux/zutil.h>
#include "nodelist.h"
#include "compr.h"

	/* Plan: call deflate() with avail_in == *sourcelen,
		avail_out = *dstlen - 12 and flush == Z_FINISH.
		If it doesn't manage to finish,	call it again with
		avail_in == 0 and avail_out set to the remaining 12
		bytes for it to clean up.
	   Q: Is 12 bytes sufficient?
	*/
#define STREAM_END_SPACE 12

static DEFINE_MUTEX(deflate_mutex);
static DEFINE_MUTEX(inflate_mutex);
static z_stream inf_strm, def_strm;

#ifdef __KERNEL__ /* Linux-only */
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/mutex.h>

static int __init alloc_workspaces(void)
{
	def_strm.workspace = vmalloc(zlib_deflate_workspacesize(MAX_WBITS,
							MAX_MEM_LEVEL));
	if (!def_strm.workspace)
		return -ENOMEM;

	jffs2_dbg(1, "Allocated %d bytes for deflate workspace\n",
		  zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL));
	inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
	if (!inf_strm.workspace) {
		vfree(def_strm.workspace);
		return -ENOMEM;
	}
	jffs2_dbg(1, "Allocated %d bytes for inflate workspace\n",
		  zlib_inflate_workspacesize());
	return 0;
}

static void free_workspaces(void)
{
	vfree(def_strm.workspace);
	vfree(inf_strm.workspace);
}
#else
#define alloc_workspaces() (0)
#define free_workspaces() do { } while(0)
#endif /* __KERNEL__ */

static int jffs2_zlib_compress(unsigned char *data_in,
			       unsigned char *cpage_out,
			       uint32_t *sourcelen, uint32_t *dstlen)
{
	int ret;

	if (*dstlen <= STREAM_END_SPACE)
		return -1;

	mutex_lock(&deflate_mutex);

	if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
		pr_warn("deflateInit failed\n");
		mutex_unlock(&deflate_mutex);
		return -1;
	}

	def_strm.next_in = data_in;
	def_strm.total_in = 0;

	def_strm.next_out = cpage_out;
	def_strm.total_out = 0;

	while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
		def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
		def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
		jffs2_dbg(1, "calling deflate with avail_in %d, avail_out %d\n",
			  def_strm.avail_in, def_strm.avail_out);
		ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
		jffs2_dbg(1, "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
			  def_strm.avail_in, def_strm.avail_out,
			  def_strm.total_in, def_strm.total_out);
		if (ret != Z_OK) {
			jffs2_dbg(1, "deflate in loop returned %d\n", ret);
			zlib_deflateEnd(&def_strm);
			mutex_unlock(&deflate_mutex);
			return -1;
		}
	}
	def_strm.avail_out += STREAM_END_SPACE;
	def_strm.avail_in = 0;
	ret = zlib_deflate(&def_strm, Z_FINISH);
	zlib_deflateEnd(&def_strm);

	if (ret != Z_STREAM_END) {
		jffs2_dbg(1, "final deflate returned %d\n", ret);
		ret = -1;
		goto out;
	}

	if (def_strm.total_out >= def_strm.total_in) {
		jffs2_dbg(1, "zlib compressed %ld bytes into %ld; failing\n",
			  def_strm.total_in, def_strm.total_out);
		ret = -1;
		goto out;
	}

	jffs2_dbg(1, "zlib compressed %ld bytes into %ld\n",
		  def_strm.total_in, def_strm.total_out);

	*dstlen = def_strm.total_out;
	*sourcelen = def_strm.total_in;
	ret = 0;
 out:
	mutex_unlock(&deflate_mutex);
	return ret;
}

static int jffs2_zlib_decompress(unsigned char *data_in,
				 unsigned char *cpage_out,
				 uint32_t srclen, uint32_t destlen)
{
	int ret;
	int wbits = MAX_WBITS;

	mutex_lock(&inflate_mutex);

	inf_strm.next_in = data_in;
	inf_strm.avail_in = srclen;
	inf_strm.total_in = 0;

	inf_strm.next_out = cpage_out;
	inf_strm.avail_out = destlen;
	inf_strm.total_out = 0;

	/* If it's deflate, and it's got no preset dictionary, then
	   we can tell zlib to skip the adler32 check. */
	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	    ((data_in[0] & 0x0f) == Z_DEFLATED) &&
	    !(((data_in[0]<<8) + data_in[1]) % 31)) {

		jffs2_dbg(2, "inflate skipping adler32\n");
		wbits = -((data_in[0] >> 4) + 8);
		inf_strm.next_in += 2;
		inf_strm.avail_in -= 2;
	} else {
		/* Let this remain D1 for now -- it should never happen */
		jffs2_dbg(1, "inflate not skipping adler32\n");
	}


	if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
		pr_warn("inflateInit failed\n");
		mutex_unlock(&inflate_mutex);
		return 1;
	}

	while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
		;
	if (ret != Z_STREAM_END) {
		pr_notice("inflate returned %d\n", ret);
	}
	zlib_inflateEnd(&inf_strm);
	mutex_unlock(&inflate_mutex);
	return 0;
}

static struct jffs2_compressor jffs2_zlib_comp = {
    .priority = JFFS2_ZLIB_PRIORITY,
    .name = "zlib",
    .compr = JFFS2_COMPR_ZLIB,
    .compress = &jffs2_zlib_compress,
    .decompress = &jffs2_zlib_decompress,
#ifdef JFFS2_ZLIB_DISABLED
    .disabled = 1,
#else
    .disabled = 0,
#endif
};

int __init jffs2_zlib_init(void)
{
    int ret;

    ret = alloc_workspaces();
    if (ret)
	    return ret;

    ret = jffs2_register_compressor(&jffs2_zlib_comp);
    if (ret)
	    free_workspaces();

    return ret;
}

void jffs2_zlib_exit(void)
{
    jffs2_unregister_compressor(&jffs2_zlib_comp);
    free_workspaces();
}