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Linux/lib/decompress_unlz4.c

  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 
 34 STATIC 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                 ret = lz4_decompress(inp, &chunksize, outp, dest_len);
156 #else
157                 dest_len = uncomp_chunksize;
158                 ret = lz4_decompress_unknownoutputsize(inp, chunksize, outp,
159                                 &dest_len);
160 #endif
161                 if (ret < 0) {
162                         error("Decoding failed");
163                         goto exit_2;
164                 }
165 
166                 ret = -1;
167                 if (flush && flush(outp, dest_len) != dest_len)
168                         goto exit_2;
169                 if (output)
170                         outp += dest_len;
171                 if (posp)
172                         *posp += chunksize;
173 
174                 if (!fill) {
175                         size -= chunksize;
176 
177                         if (size == 0)
178                                 break;
179                         else if (size < 0) {
180                                 error("data corrupted");
181                                 goto exit_2;
182                         }
183                         inp += chunksize;
184                 }
185         }
186 
187         ret = 0;
188 exit_2:
189         if (!input)
190                 large_free(inp_start);
191 exit_1:
192         if (!output)
193                 large_free(outp);
194 exit_0:
195         return ret;
196 }
197 
198 #ifdef PREBOOT
199 STATIC int INIT __decompress(unsigned char *buf, long in_len,
200                               long (*fill)(void*, unsigned long),
201                               long (*flush)(void*, unsigned long),
202                               unsigned char *output, long out_len,
203                               long *posp,
204                               void (*error)(char *x)
205         )
206 {
207         return unlz4(buf, in_len - 4, fill, flush, output, posp, error);
208 }
209 #endif
210 

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