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 #include "decompress.h"
12 #include <xen/lz4.h>
13 #include "lz4/decompress.c"
14
15 /*
16 * Note: Uncompressed chunk size is used in the compressor side
17 * (userspace side for compression).
18 * It is hardcoded because there is not proper way to extract it
19 * from the binary stream which is generated by the preliminary
20 * version of LZ4 tool so far.
21 */
22 #define LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE (8 << 20)
23 #define ARCHIVE_MAGICNUMBER 0x184C2102
24
unlz4(unsigned char * input,unsigned int in_len,int (* fill)(void *,unsigned int),int (* flush)(void *,unsigned int),unsigned char * output,unsigned int * posp,void (* error)(const char * x))25 int __init unlz4(unsigned char *input, unsigned int in_len,
26 int (*fill)(void *, unsigned int),
27 int (*flush)(void *, unsigned int),
28 unsigned char *output, unsigned int *posp,
29 void (*error)(const char *x))
30 {
31 int ret = -1;
32 size_t chunksize = 0;
33 size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
34 u8 *inp;
35 u8 *inp_start;
36 u8 *outp;
37 int size = in_len -= 4;
38 #if defined(__XEN__) || defined(__MINIOS__)
39 size_t out_len = get_unaligned_le32(input + in_len);
40 #endif
41 size_t dest_len;
42
43
44 if (output) {
45 outp = output;
46 } else if (!flush) {
47 error("NULL output pointer and no flush function provided");
48 goto exit_0;
49 } else {
50 outp = large_malloc(uncomp_chunksize);
51 if (!outp) {
52 error("Could not allocate output buffer");
53 goto exit_0;
54 }
55 }
56
57 if (input && fill) {
58 error("Both input pointer and fill function provided,");
59 goto exit_1;
60 } else if (input) {
61 inp = input;
62 } else if (!fill) {
63 error("NULL input pointer and missing fill function");
64 goto exit_1;
65 } else {
66 inp = large_malloc(lz4_compressbound(uncomp_chunksize));
67 if (!inp) {
68 error("Could not allocate input buffer");
69 goto exit_1;
70 }
71 }
72 inp_start = inp;
73
74 if (posp)
75 *posp = 0;
76
77 if (fill)
78 fill(inp, 4);
79
80 chunksize = get_unaligned_le32(inp);
81 if (chunksize == ARCHIVE_MAGICNUMBER) {
82 inp += 4;
83 size -= 4;
84 } else {
85 error("invalid header");
86 goto exit_2;
87 }
88
89 if (posp)
90 *posp += 4;
91
92 for (;;) {
93
94 if (fill)
95 fill(inp, 4);
96
97 chunksize = get_unaligned_le32(inp);
98 if (chunksize == ARCHIVE_MAGICNUMBER) {
99 inp += 4;
100 size -= 4;
101 if (posp)
102 *posp += 4;
103 continue;
104 }
105 inp += 4;
106 size -= 4;
107
108 if (posp)
109 *posp += 4;
110
111 if (fill) {
112 if (chunksize > lz4_compressbound(uncomp_chunksize)) {
113 error("chunk length is longer than allocated");
114 goto exit_2;
115 }
116 fill(inp, chunksize);
117 }
118 #if defined(__XEN__) || defined(__MINIOS__)
119 if (out_len >= uncomp_chunksize) {
120 dest_len = uncomp_chunksize;
121 out_len -= dest_len;
122 } else
123 dest_len = out_len;
124 ret = lz4_decompress(inp, &chunksize, outp, dest_len);
125 #else
126 dest_len = uncomp_chunksize;
127 ret = lz4_decompress_unknownoutputsize(inp, chunksize, outp,
128 &dest_len);
129 #endif
130 if (ret < 0) {
131 error("Decoding failed");
132 goto exit_2;
133 }
134
135 ret = -1;
136 if (flush && flush(outp, dest_len) != dest_len)
137 goto exit_2;
138 if (output)
139 outp += dest_len;
140 if (posp)
141 *posp += chunksize;
142
143 size -= chunksize;
144
145 if (size == 0)
146 break;
147 else if (size < 0) {
148 error("data corrupted");
149 goto exit_2;
150 }
151
152 inp += chunksize;
153 if (fill)
154 inp = inp_start;
155 }
156
157 ret = 0;
158 exit_2:
159 if (!input)
160 large_free(inp_start);
161 exit_1:
162 if (!output)
163 large_free(outp);
164 exit_0:
165 return ret;
166 }
167