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