git.zerfleddert.de Git - rsbs2/blob - rsb-lz.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <strings.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6 #include <errno.h>
   7 #include "rsb-crc.h"
   8 #include "rsb-lz.h"
   9 #include "filesystem.h"
  10
  11 void err_exit(const char *fname)
  12 {
  13         fprintf(stderr,"%s: error extracting...\n", fname);
  14         exit(1);
  15 }
  16
  17 struct data_in_s {
  18         unsigned char *start;
  19         unsigned char *stop;
  20         unsigned char bitpos;
  21         unsigned char byte;
  22 };
  23
  24 struct data_out_s {
  25         unsigned char *pos;
  26         unsigned char *end;
  27 };
  28
  29 unsigned char get_next_in_byte(struct data_in_s *data_in)
  30 {
  31         unsigned char byte;
  32
  33         if (data_in->stop < data_in->start)
  34                 err_exit(__func__);
  35
  36         byte = *(data_in->start);
  37         data_in->start++;
  38
  39         return byte;
  40 }
  41
  42 unsigned char get_next_bit(struct data_in_s *data_in)
  43 {
  44         unsigned char bitval;
  45
  46         if (data_in->bitpos == 0x80) {
  47                 data_in->byte = get_next_in_byte(data_in);
  48         }
  49
  50         bitval = data_in->bitpos & data_in->byte;
  51
  52         data_in->bitpos >>= 1;
  53         if (data_in->bitpos == 0) {
  54                 data_in->bitpos = 0x80;
  55         }
  56
  57         if (bitval == 0)
  58                 return 0;
  59
  60         return 1;
  61 }
  62
  63 unsigned int get_next_bits(struct data_in_s *data_in, unsigned int bits)
  64 {
  65         unsigned int bit;
  66         unsigned int next_bits;
  67
  68         bit = 1 << (bits - 1);
  69
  70         next_bits = 0;
  71         while (bit != 0) {
  72                 if (data_in->bitpos == 0x80) {
  73                         data_in->byte = get_next_in_byte(data_in);
  74                 }
  75
  76                 if ((data_in->bitpos & data_in->byte) != 0)
  77                         next_bits = next_bits | bit;
  78
  79                 bit = bit >> 1;
  80
  81                 data_in->bitpos >>= 1;
  82
  83                 if(data_in->bitpos == 0) {
  84                         data_in->bitpos = 0x80;
  85                 }
  86         }
  87
  88         return next_bits;
  89 }
  90
  91 void write_byte(unsigned char byte, struct data_out_s *data_out)
  92 {
  93         if (data_out->pos > data_out->end) {
  94                 err_exit(__func__);
  95         }
  96
  97         *(data_out->pos) = byte;
  98         data_out->pos++;
  99 }
 100
 101 void lz_expand(struct data_in_s *data_in, struct data_out_s *data_out)
 102 {
 103         unsigned int pos;
 104         unsigned int offset;
 105         unsigned int i;
 106         unsigned char byte;
 107         unsigned int num;
 108         unsigned char buf[1024];
 109
 110         pos = 1;
 111
 112         while (1) {
 113                 while (1) {
 114                         if (get_next_bit(data_in) == 0)
 115                                 break;
 116
 117                         byte = get_next_bits(data_in, 8);
 118
 119                         write_byte(byte, data_out);
 120                         buf[pos] = byte;
 121                         pos = (pos + 1) & 0x3ff;
 122                 }
 123
 124                 offset = get_next_bits(data_in, 0x0a);
 125                 if(offset == 0)
 126                         return;
 127
 128                 num = get_next_bits(data_in, 0x04) + 1;
 129                 for (i = 0; i <= num; i++) {
 130                         byte = buf[(offset + i) & 0x3ff];
 131                         write_byte(byte, data_out);
 132                         buf[pos] = byte;
 133                         pos = (pos + 1) & 0x3ff;
 134                 }
 135         }
 136 }
 137
 138 /* Checksum is only used for the compressed firmware in 'firmware' */
 139 unsigned int crc_check(unsigned char *buf, unsigned int len, unsigned int magic)
 140 {
 141         unsigned int file_crc;
 142         unsigned int my_len;
 143         unsigned int crc;
 144         unsigned int my_magic;
 145
 146         my_len = *((unsigned int*)(buf + 0x20));
 147         my_magic = *((unsigned int*)(buf + 0x24));
 148
 149         if (my_magic != magic) {
 150                 printf("\nmagic: 0x%08x <-> 0x%08x\n", my_magic, magic);
 151                 return 2;
 152         }
 153
 154         if (len < my_len)
 155                 return 3;
 156
 157         crc = ~rsb_crc(~0x00, buf, len);
 158         file_crc = *((unsigned int*)(buf + len));
 159
 160         if (file_crc != crc) {
 161                 printf("\nChecksums: 0x%08x <-> 0x%08x!\n", crc, file_crc);
 162                 return 4;
 163         }
 164
 165         return 0;
 166 }
 167
 168 void extract_lz_file(unsigned char *inbuf, unsigned char *name, unsigned char check_crc)
 169 {
 170         unsigned int len;
 171         unsigned char *outbuf;
 172         struct data_in_s data_in;
 173         struct data_out_s data_out;
 174
 175         if (*((unsigned int*)inbuf) != LZ_MAGIC)
 176                 err_exit(__func__);
 177
 178         len = *((unsigned int*)(inbuf + 4));
 179         printf(", length: %d", len);
 180
 181         if ((outbuf = malloc(len)) == NULL) {
 182                 perror("malloc");
 183                 exit(1);
 184         }
 185
 186         bzero(outbuf, len);
 187
 188         data_in.start = inbuf + 8;
 189         data_in.stop = inbuf + len;
 190         data_in.byte = 0x00;
 191         data_in.bitpos = 0x80;
 192
 193         data_out.pos = outbuf;
 194         data_out.end = outbuf + len;
 195
 196         lz_expand(&data_in, &data_out);
 197
 198         if (check_crc) {
 199                 unsigned int crclen;
 200                 int ret;
 201
 202                 crclen = *((unsigned int*)(outbuf + 0x20));
 203
 204                 if ((ret = crc_check(outbuf, crclen, 0x46335053)) != 0) {
 205                         printf("crc_check return: %d\n", ret);
 206                         err_exit(__func__);
 207                 }
 208         }
 209
 210         write_file((char*)name, outbuf, len);
 211
 212         free(outbuf);
 213 }