aboutsummaryrefslogtreecommitdiffstats
path: root/module/spl/spl-zlib.c
blob: c42562f8123a617bcc01986d92cdc75297df83f3 (plain)
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
/*****************************************************************************\
 *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
 *  Copyright (C) 2007 The Regents of the University of California.
 *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
 *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
 *  UCRL-CODE-235197
 *
 *  This file is part of the SPL, Solaris Porting Layer.
 *  For details, see <http://github.com/behlendorf/spl/>.
 *
 *  The SPL is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by the
 *  Free Software Foundation; either version 2 of the License, or (at your
 *  option) any later version.
 *
 *  The SPL is distributed in the hope that it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
 *****************************************************************************
 *  z_compress_level/z_uncompress are nearly identical copies of the
 *  compress2/uncompress functions provided by the official zlib package
 *  available at http://zlib.net/.  The only changes made we to slightly
 *  adapt the functions called to match the linux kernel implementation
 *  of zlib.  The full zlib license follows:
 *
 *  zlib.h -- interface of the 'zlib' general purpose compression library
 *  version 1.2.5, April 19th, 2010
 *
 *  Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler
 *
 *  This software is provided 'as-is', without any express or implied
 *  warranty.  In no event will the authors be held liable for any damages
 *  arising from the use of this software.
 *
 *  Permission is granted to anyone to use this software for any purpose,
 *  including commercial applications, and to alter it and redistribute it
 *  freely, subject to the following restrictions:
 *
 *  1. The origin of this software must not be misrepresented; you must not
 *     claim that you wrote the original software. If you use this software
 *     in a product, an acknowledgment in the product documentation would be
 *     appreciated but is not required.
 *  2. Altered source versions must be plainly marked as such, and must not be
 *     misrepresented as being the original software.
 *  3. This notice may not be removed or altered from any source distribution.
 *
 *  Jean-loup Gailly
 *  Mark Adler
\*****************************************************************************/


#include <sys/kmem.h>
#include <sys/zmod.h>
#include <spl-debug.h>

#ifdef DEBUG_SUBSYSTEM
#undef DEBUG_SUBSYSTEM
#endif

#define DEBUG_SUBSYSTEM SS_ZLIB

static spl_kmem_cache_t *zlib_workspace_cache;

/*
 * A kmem_cache is used for the zlib workspaces to avoid having to vmalloc
 * and vfree for every call.  Using a kmem_cache also has the advantage
 * that improves the odds that the memory used will be local to this cpu.
 * To further improve things it might be wise to create a dedicated per-cpu
 * workspace for use.  This would take some additional care because we then
 * must disable preemption around the critical section, and verify that
 * zlib_deflate* and zlib_inflate* never internally call schedule().
 */
static void *
zlib_workspace_alloc(int flags)
{
	return kmem_cache_alloc(zlib_workspace_cache, flags & ~(__GFP_FS));
}

static void
zlib_workspace_free(void *workspace)
{
	kmem_cache_free(zlib_workspace_cache, workspace);
}

/*
 * Compresses the source buffer into the destination buffer. The level
 * parameter has the same meaning as in deflateInit.  sourceLen is the byte
 * length of the source buffer. Upon entry, destLen is the total size of the
 * destination buffer, which must be at least 0.1% larger than sourceLen plus
 * 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
 *
 * compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
 * memory, Z_BUF_ERROR if there was not enough room in the output buffer,
 * Z_STREAM_ERROR if the level parameter is invalid.
 */
int
z_compress_level(void *dest, size_t *destLen, const void *source,
                 size_t sourceLen, int level)
{
	z_stream stream;
	int err;

	stream.next_in = (Byte *)source;
	stream.avail_in = (uInt)sourceLen;
	stream.next_out = dest;
	stream.avail_out = (uInt)*destLen;

	if ((size_t)stream.avail_out != *destLen)
		return Z_BUF_ERROR;

	stream.workspace = zlib_workspace_alloc(KM_SLEEP);
	if (!stream.workspace)
		return Z_MEM_ERROR;

	err = zlib_deflateInit(&stream, level);
	if (err != Z_OK) {
		zlib_workspace_free(stream.workspace);
		return err;
	}

	err = zlib_deflate(&stream, Z_FINISH);
	if (err != Z_STREAM_END) {
		zlib_deflateEnd(&stream);
		zlib_workspace_free(stream.workspace);
		return err == Z_OK ? Z_BUF_ERROR : err;
	}
	*destLen = stream.total_out;

	err = zlib_deflateEnd(&stream);
	zlib_workspace_free(stream.workspace);

	return err;
}
EXPORT_SYMBOL(z_compress_level);

/*
 * Decompresses the source buffer into the destination buffer.  sourceLen is
 * the byte length of the source buffer. Upon entry, destLen is the total
 * size of the destination buffer, which must be large enough to hold the
 * entire uncompressed data. (The size of the uncompressed data must have
 * been saved previously by the compressor and transmitted to the decompressor
 * by some mechanism outside the scope of this compression library.)
 * Upon exit, destLen is the actual size of the compressed buffer.
 * This function can be used to decompress a whole file at once if the
 * input file is mmap'ed.
 *
 * uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
 * enough memory, Z_BUF_ERROR if there was not enough room in the output
 * buffer, or Z_DATA_ERROR if the input data was corrupted.
 */
int
z_uncompress(void *dest, size_t *destLen, const void *source, size_t sourceLen)
{
	z_stream stream;
	int err;

	stream.next_in = (Byte *)source;
	stream.avail_in = (uInt)sourceLen;
	stream.next_out = dest;
	stream.avail_out = (uInt)*destLen;

	if ((size_t)stream.avail_out != *destLen)
		return Z_BUF_ERROR;

	stream.workspace = zlib_workspace_alloc(KM_SLEEP);
	if (!stream.workspace)
		return Z_MEM_ERROR;

	err = zlib_inflateInit(&stream);
	if (err != Z_OK) {
		zlib_workspace_free(stream.workspace);
		return err;
	}

	err = zlib_inflate(&stream, Z_FINISH);
	if (err != Z_STREAM_END) {
		zlib_inflateEnd(&stream);
		zlib_workspace_free(stream.workspace);

		if (err == Z_NEED_DICT ||
		   (err == Z_BUF_ERROR && stream.avail_in == 0))
			return Z_DATA_ERROR;

		return err;
	}
	*destLen = stream.total_out;

	err = zlib_inflateEnd(&stream);
	zlib_workspace_free(stream.workspace);

	return err;
}
EXPORT_SYMBOL(z_uncompress);

int zlib_init(void)
{
	int size;
        SENTRY;

	size = MAX(spl_zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
	    zlib_inflate_workspacesize());

	zlib_workspace_cache = kmem_cache_create("spl_zlib_workspace_cache",
	    size, 0, NULL, NULL, NULL, NULL, NULL, KMC_VMEM);
        if (!zlib_workspace_cache)
		SRETURN(1);

        SRETURN(0);
}

void zlib_fini(void)
{
        SENTRY;
	kmem_cache_destroy(zlib_workspace_cache);
        zlib_workspace_cache = NULL;
        SEXIT;
}