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1 /* |
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2 * QEMU Block driver for DMG images |
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3 * |
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4 * Copyright (c) 2004 Johannes E. Schindelin |
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5 * |
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6 * Permission is hereby granted, free of charge, to any person obtaining a copy |
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7 * of this software and associated documentation files (the "Software"), to deal |
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8 * in the Software without restriction, including without limitation the rights |
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9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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10 * copies of the Software, and to permit persons to whom the Software is |
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11 * furnished to do so, subject to the following conditions: |
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12 * |
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13 * The above copyright notice and this permission notice shall be included in |
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14 * all copies or substantial portions of the Software. |
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15 * |
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16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
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19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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22 * THE SOFTWARE. |
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23 */ |
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24 #include "qemu-common.h" |
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25 #include "block_int.h" |
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26 #include "bswap.h" |
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27 #include <zlib.h> |
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28 |
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29 typedef struct BDRVDMGState { |
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30 int fd; |
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31 |
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32 /* each chunk contains a certain number of sectors, |
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33 * offsets[i] is the offset in the .dmg file, |
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34 * lengths[i] is the length of the compressed chunk, |
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35 * sectors[i] is the sector beginning at offsets[i], |
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36 * sectorcounts[i] is the number of sectors in that chunk, |
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37 * the sectors array is ordered |
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38 * 0<=i<n_chunks */ |
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39 |
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40 uint32_t n_chunks; |
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41 uint32_t* types; |
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42 uint64_t* offsets; |
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43 uint64_t* lengths; |
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44 uint64_t* sectors; |
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45 uint64_t* sectorcounts; |
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46 uint32_t current_chunk; |
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47 uint8_t *compressed_chunk; |
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48 uint8_t *uncompressed_chunk; |
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49 z_stream zstream; |
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50 } BDRVDMGState; |
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51 |
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52 static int dmg_probe(const uint8_t *buf, int buf_size, const char *filename) |
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53 { |
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54 int len=strlen(filename); |
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55 if(len>4 && !strcmp(filename+len-4,".dmg")) |
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56 return 2; |
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57 return 0; |
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58 } |
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59 |
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60 static off_t read_off(int fd) |
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61 { |
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62 uint64_t buffer; |
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63 if(read(fd,&buffer,8)<8) |
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64 return 0; |
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65 return be64_to_cpu(buffer); |
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66 } |
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67 |
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68 static off_t read_uint32(int fd) |
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69 { |
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70 uint32_t buffer; |
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71 if(read(fd,&buffer,4)<4) |
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72 return 0; |
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73 return be32_to_cpu(buffer); |
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74 } |
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75 |
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76 static int dmg_open(BlockDriverState *bs, const char *filename, int flags) |
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77 { |
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78 BDRVDMGState *s = bs->opaque; |
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79 off_t info_begin,info_end,last_in_offset,last_out_offset; |
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80 uint32_t count; |
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81 uint32_t max_compressed_size=1,max_sectors_per_chunk=1,i; |
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82 |
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83 s->fd = open(filename, O_RDONLY | O_BINARY); |
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84 if (s->fd < 0) |
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85 return -errno; |
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86 bs->read_only = 1; |
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87 s->n_chunks = 0; |
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88 s->offsets = s->lengths = s->sectors = s->sectorcounts = 0; |
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89 |
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90 /* read offset of info blocks */ |
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91 if(lseek(s->fd,-0x1d8,SEEK_END)<0) { |
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92 dmg_close: |
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93 close(s->fd); |
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94 /* open raw instead */ |
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95 bs->drv=&bdrv_raw; |
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96 return bs->drv->bdrv_open(bs, filename, flags); |
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97 } |
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98 info_begin=read_off(s->fd); |
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99 if(info_begin==0) |
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100 goto dmg_close; |
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101 if(lseek(s->fd,info_begin,SEEK_SET)<0) |
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102 goto dmg_close; |
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103 if(read_uint32(s->fd)!=0x100) |
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104 goto dmg_close; |
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105 if((count = read_uint32(s->fd))==0) |
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106 goto dmg_close; |
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107 info_end = info_begin+count; |
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108 if(lseek(s->fd,0xf8,SEEK_CUR)<0) |
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109 goto dmg_close; |
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110 |
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111 /* read offsets */ |
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112 last_in_offset = last_out_offset = 0; |
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113 while(lseek(s->fd,0,SEEK_CUR)<info_end) { |
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114 uint32_t type; |
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115 |
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116 count = read_uint32(s->fd); |
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117 if(count==0) |
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118 goto dmg_close; |
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119 type = read_uint32(s->fd); |
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120 if(type!=0x6d697368 || count<244) |
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121 lseek(s->fd,count-4,SEEK_CUR); |
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122 else { |
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123 int new_size, chunk_count; |
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124 if(lseek(s->fd,200,SEEK_CUR)<0) |
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125 goto dmg_close; |
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126 chunk_count = (count-204)/40; |
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127 new_size = sizeof(uint64_t) * (s->n_chunks + chunk_count); |
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128 s->types = qemu_realloc(s->types, new_size/2); |
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129 s->offsets = qemu_realloc(s->offsets, new_size); |
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130 s->lengths = qemu_realloc(s->lengths, new_size); |
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131 s->sectors = qemu_realloc(s->sectors, new_size); |
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132 s->sectorcounts = qemu_realloc(s->sectorcounts, new_size); |
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133 |
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134 for(i=s->n_chunks;i<s->n_chunks+chunk_count;i++) { |
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135 s->types[i] = read_uint32(s->fd); |
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136 if(s->types[i]!=0x80000005 && s->types[i]!=1 && s->types[i]!=2) { |
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137 if(s->types[i]==0xffffffff) { |
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138 last_in_offset = s->offsets[i-1]+s->lengths[i-1]; |
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139 last_out_offset = s->sectors[i-1]+s->sectorcounts[i-1]; |
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140 } |
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141 chunk_count--; |
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142 i--; |
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143 if(lseek(s->fd,36,SEEK_CUR)<0) |
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144 goto dmg_close; |
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145 continue; |
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146 } |
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147 read_uint32(s->fd); |
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148 s->sectors[i] = last_out_offset+read_off(s->fd); |
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149 s->sectorcounts[i] = read_off(s->fd); |
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150 s->offsets[i] = last_in_offset+read_off(s->fd); |
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151 s->lengths[i] = read_off(s->fd); |
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152 if(s->lengths[i]>max_compressed_size) |
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153 max_compressed_size = s->lengths[i]; |
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154 if(s->sectorcounts[i]>max_sectors_per_chunk) |
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155 max_sectors_per_chunk = s->sectorcounts[i]; |
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156 } |
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157 s->n_chunks+=chunk_count; |
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158 } |
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159 } |
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160 |
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161 /* initialize zlib engine */ |
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162 if(!(s->compressed_chunk = malloc(max_compressed_size+1))) |
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163 goto dmg_close; |
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164 if(!(s->uncompressed_chunk = malloc(512*max_sectors_per_chunk))) |
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165 goto dmg_close; |
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166 if(inflateInit(&s->zstream) != Z_OK) |
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167 goto dmg_close; |
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168 |
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169 s->current_chunk = s->n_chunks; |
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170 |
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171 return 0; |
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172 } |
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173 |
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174 static inline int is_sector_in_chunk(BDRVDMGState* s, |
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175 uint32_t chunk_num,int sector_num) |
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176 { |
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177 if(chunk_num>=s->n_chunks || s->sectors[chunk_num]>sector_num || |
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178 s->sectors[chunk_num]+s->sectorcounts[chunk_num]<=sector_num) |
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179 return 0; |
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180 else |
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181 return -1; |
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182 } |
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183 |
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184 static inline uint32_t search_chunk(BDRVDMGState* s,int sector_num) |
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185 { |
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186 /* binary search */ |
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187 uint32_t chunk1=0,chunk2=s->n_chunks,chunk3; |
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188 while(chunk1!=chunk2) { |
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189 chunk3 = (chunk1+chunk2)/2; |
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190 if(s->sectors[chunk3]>sector_num) |
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191 chunk2 = chunk3; |
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192 else if(s->sectors[chunk3]+s->sectorcounts[chunk3]>sector_num) |
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193 return chunk3; |
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194 else |
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195 chunk1 = chunk3; |
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196 } |
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197 return s->n_chunks; /* error */ |
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198 } |
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199 |
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200 static inline int dmg_read_chunk(BDRVDMGState *s,int sector_num) |
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201 { |
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202 if(!is_sector_in_chunk(s,s->current_chunk,sector_num)) { |
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203 int ret; |
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204 uint32_t chunk = search_chunk(s,sector_num); |
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205 |
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206 if(chunk>=s->n_chunks) |
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207 return -1; |
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208 |
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209 s->current_chunk = s->n_chunks; |
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210 switch(s->types[chunk]) { |
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211 case 0x80000005: { /* zlib compressed */ |
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212 int i; |
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213 |
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214 ret = lseek(s->fd, s->offsets[chunk], SEEK_SET); |
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215 if(ret<0) |
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216 return -1; |
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217 |
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218 /* we need to buffer, because only the chunk as whole can be |
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219 * inflated. */ |
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220 i=0; |
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221 do { |
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222 ret = read(s->fd, s->compressed_chunk+i, s->lengths[chunk]-i); |
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223 if(ret<0 && errno==EINTR) |
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224 ret=0; |
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225 i+=ret; |
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226 } while(ret>=0 && ret+i<s->lengths[chunk]); |
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227 |
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228 if (ret != s->lengths[chunk]) |
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229 return -1; |
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230 |
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231 s->zstream.next_in = s->compressed_chunk; |
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232 s->zstream.avail_in = s->lengths[chunk]; |
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233 s->zstream.next_out = s->uncompressed_chunk; |
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234 s->zstream.avail_out = 512*s->sectorcounts[chunk]; |
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235 ret = inflateReset(&s->zstream); |
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236 if(ret != Z_OK) |
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237 return -1; |
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238 ret = inflate(&s->zstream, Z_FINISH); |
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239 if(ret != Z_STREAM_END || s->zstream.total_out != 512*s->sectorcounts[chunk]) |
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240 return -1; |
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241 break; } |
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242 case 1: /* copy */ |
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243 ret = read(s->fd, s->uncompressed_chunk, s->lengths[chunk]); |
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244 if (ret != s->lengths[chunk]) |
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245 return -1; |
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246 break; |
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247 case 2: /* zero */ |
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248 memset(s->uncompressed_chunk, 0, 512*s->sectorcounts[chunk]); |
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249 break; |
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250 } |
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251 s->current_chunk = chunk; |
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252 } |
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253 return 0; |
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254 } |
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255 |
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256 static int dmg_read(BlockDriverState *bs, int64_t sector_num, |
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257 uint8_t *buf, int nb_sectors) |
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258 { |
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259 BDRVDMGState *s = bs->opaque; |
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260 int i; |
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261 |
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262 for(i=0;i<nb_sectors;i++) { |
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263 uint32_t sector_offset_in_chunk; |
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264 if(dmg_read_chunk(s, sector_num+i) != 0) |
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265 return -1; |
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266 sector_offset_in_chunk = sector_num+i-s->sectors[s->current_chunk]; |
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267 memcpy(buf+i*512,s->uncompressed_chunk+sector_offset_in_chunk*512,512); |
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268 } |
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269 return 0; |
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270 } |
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271 |
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272 static void dmg_close(BlockDriverState *bs) |
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273 { |
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274 BDRVDMGState *s = bs->opaque; |
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275 close(s->fd); |
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276 if(s->n_chunks>0) { |
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277 free(s->types); |
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278 free(s->offsets); |
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279 free(s->lengths); |
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280 free(s->sectors); |
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281 free(s->sectorcounts); |
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282 } |
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283 free(s->compressed_chunk); |
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284 free(s->uncompressed_chunk); |
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285 inflateEnd(&s->zstream); |
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286 } |
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287 |
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288 BlockDriver bdrv_dmg = { |
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289 "dmg", |
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290 sizeof(BDRVDMGState), |
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291 dmg_probe, |
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292 dmg_open, |
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293 dmg_read, |
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294 NULL, |
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295 dmg_close, |
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296 }; |