1/*
2 * Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
3 *
4 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#ifdef STATIC
12#define PREBOOT
13#include "lz4/lz4_decompress.c"
14#else
15#include <linux/decompress/unlz4.h>
16#endif
17#include <linux/types.h>
18#include <linux/lz4.h>
19#include <linux/decompress/mm.h>
20#include <linux/compiler.h>
21
22#include <asm/unaligned.h>
23
24/*
25 * Note: Uncompressed chunk size is used in the compressor side
26 * (userspace side for compression).
27 * It is hardcoded because there is not proper way to extract it
28 * from the binary stream which is generated by the preliminary
29 * version of LZ4 tool so far.
30 */
31#define LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE (8 << 20)
32#define ARCHIVE_MAGICNUMBER 0x184C2102
33
34STATIC inline int INIT unlz4(u8 *input, long in_len,
35 long (*fill)(void *, unsigned long),
36 long (*flush)(void *, unsigned long),
37 u8 *output, long *posp,
38 void (*error) (char *x))
39{
40 int ret = -1;
41 size_t chunksize = 0;
42 size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
43 u8 *inp;
44 u8 *inp_start;
45 u8 *outp;
46 long size = in_len;
47#ifdef PREBOOT
48 size_t out_len = get_unaligned_le32(input + in_len);
49#endif
50 size_t dest_len;
51
52
53 if (output) {
54 outp = output;
55 } else if (!flush) {
56 error("NULL output pointer and no flush function provided");
57 goto exit_0;
58 } else {
59 outp = large_malloc(uncomp_chunksize);
60 if (!outp) {
61 error("Could not allocate output buffer");
62 goto exit_0;
63 }
64 }
65
66 if (input && fill) {
67 error("Both input pointer and fill function provided,");
68 goto exit_1;
69 } else if (input) {
70 inp = input;
71 } else if (!fill) {
72 error("NULL input pointer and missing fill function");
73 goto exit_1;
74 } else {
75 inp = large_malloc(LZ4_compressBound(uncomp_chunksize));
76 if (!inp) {
77 error("Could not allocate input buffer");
78 goto exit_1;
79 }
80 }
81 inp_start = inp;
82
83 if (posp)
84 *posp = 0;
85
86 if (fill) {
87 size = fill(inp, 4);
88 if (size < 4) {
89 error("data corrupted");
90 goto exit_2;
91 }
92 }
93
94 chunksize = get_unaligned_le32(inp);
95 if (chunksize == ARCHIVE_MAGICNUMBER) {
96 if (!fill) {
97 inp += 4;
98 size -= 4;
99 }
100 } else {
101 error("invalid header");
102 goto exit_2;
103 }
104
105 if (posp)
106 *posp += 4;
107
108 for (;;) {
109
110 if (fill) {
111 size = fill(inp, 4);
112 if (size == 0)
113 break;
114 if (size < 4) {
115 error("data corrupted");
116 goto exit_2;
117 }
118 }
119
120 chunksize = get_unaligned_le32(inp);
121 if (chunksize == ARCHIVE_MAGICNUMBER) {
122 if (!fill) {
123 inp += 4;
124 size -= 4;
125 }
126 if (posp)
127 *posp += 4;
128 continue;
129 }
130
131
132 if (posp)
133 *posp += 4;
134
135 if (!fill) {
136 inp += 4;
137 size -= 4;
138 } else {
139 if (chunksize > LZ4_compressBound(uncomp_chunksize)) {
140 error("chunk length is longer than allocated");
141 goto exit_2;
142 }
143 size = fill(inp, chunksize);
144 if (size < chunksize) {
145 error("data corrupted");
146 goto exit_2;
147 }
148 }
149#ifdef PREBOOT
150 if (out_len >= uncomp_chunksize) {
151 dest_len = uncomp_chunksize;
152 out_len -= dest_len;
153 } else
154 dest_len = out_len;
155
156 ret = LZ4_decompress_fast(inp, outp, dest_len);
157 chunksize = ret;
158#else
159 dest_len = uncomp_chunksize;
160
161 ret = LZ4_decompress_safe(inp, outp, chunksize, dest_len);
162 dest_len = ret;
163#endif
164 if (ret < 0) {
165 error("Decoding failed");
166 goto exit_2;
167 }
168
169 ret = -1;
170 if (flush && flush(outp, dest_len) != dest_len)
171 goto exit_2;
172 if (output)
173 outp += dest_len;
174 if (posp)
175 *posp += chunksize;
176
177 if (!fill) {
178 size -= chunksize;
179
180 if (size == 0)
181 break;
182 else if (size < 0) {
183 error("data corrupted");
184 goto exit_2;
185 }
186 inp += chunksize;
187 }
188 }
189
190 ret = 0;
191exit_2:
192 if (!input)
193 large_free(inp_start);
194exit_1:
195 if (!output)
196 large_free(outp);
197exit_0:
198 return ret;
199}
200
201#ifdef PREBOOT
202STATIC int INIT __decompress(unsigned char *buf, long in_len,
203 long (*fill)(void*, unsigned long),
204 long (*flush)(void*, unsigned long),
205 unsigned char *output, long out_len,
206 long *posp,
207 void (*error)(char *x)
208 )
209{
210 return unlz4(buf, in_len - 4, fill, flush, output, posp, error);
211}
212#endif
213