1 | /* |
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2 | * QEMU Block driver for CLOOP 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 "vl.h" |
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25 | #include "block_int.h" |
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26 | #include <zlib.h> |
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27 | |
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28 | typedef struct BDRVCloopState { |
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29 | int fd; |
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30 | uint32_t block_size; |
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31 | uint32_t n_blocks; |
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32 | uint64_t* offsets; |
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33 | uint32_t sectors_per_block; |
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34 | uint32_t current_block; |
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35 | uint8_t *compressed_block; |
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36 | uint8_t *uncompressed_block; |
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37 | z_stream zstream; |
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38 | } BDRVCloopState; |
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39 | |
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40 | static int cloop_probe(const uint8_t *buf, int buf_size, const char *filename) |
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41 | { |
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42 | const char* magic_version_2_0="#!/bin/sh\n" |
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43 | "#V2.0 Format\n" |
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44 | "modprobe cloop file=$0 && mount -r -t iso9660 /dev/cloop $1\n"; |
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45 | int length=strlen(magic_version_2_0); |
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46 | if(length>buf_size) |
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47 | length=buf_size; |
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48 | if(!memcmp(magic_version_2_0,buf,length)) |
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49 | return 2; |
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50 | return 0; |
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51 | } |
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52 | |
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53 | static int cloop_open(BlockDriverState *bs, const char *filename) |
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54 | { |
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55 | BDRVCloopState *s = bs->opaque; |
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56 | uint32_t offsets_size,max_compressed_block_size=1,i; |
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57 | |
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58 | s->fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE); |
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59 | if (s->fd < 0) |
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60 | return -1; |
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61 | bs->read_only = 1; |
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62 | |
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63 | /* read header */ |
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64 | if(lseek(s->fd,128,SEEK_SET)<0) { |
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65 | cloop_close: |
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66 | close(s->fd); |
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67 | return -1; |
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68 | } |
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69 | if(read(s->fd,&s->block_size,4)<4) |
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70 | goto cloop_close; |
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71 | s->block_size=be32_to_cpu(s->block_size); |
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72 | if(read(s->fd,&s->n_blocks,4)<4) |
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73 | goto cloop_close; |
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74 | s->n_blocks=be32_to_cpu(s->n_blocks); |
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75 | |
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76 | /* read offsets */ |
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77 | offsets_size=s->n_blocks*sizeof(uint64_t); |
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78 | if(!(s->offsets=(uint64_t*)malloc(offsets_size))) |
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79 | goto cloop_close; |
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80 | if(read(s->fd,s->offsets,offsets_size)<offsets_size) |
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81 | goto cloop_close; |
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82 | for(i=0;i<s->n_blocks;i++) { |
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83 | s->offsets[i]=be64_to_cpu(s->offsets[i]); |
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84 | if(i>0) { |
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85 | uint32_t size=s->offsets[i]-s->offsets[i-1]; |
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86 | if(size>max_compressed_block_size) |
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87 | max_compressed_block_size=size; |
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88 | } |
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89 | } |
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90 | |
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91 | /* initialize zlib engine */ |
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92 | if(!(s->compressed_block = malloc(max_compressed_block_size+1))) |
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93 | goto cloop_close; |
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94 | if(!(s->uncompressed_block = malloc(s->block_size))) |
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95 | goto cloop_close; |
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96 | if(inflateInit(&s->zstream) != Z_OK) |
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97 | goto cloop_close; |
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98 | s->current_block=s->n_blocks; |
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99 | |
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100 | s->sectors_per_block = s->block_size/512; |
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101 | bs->total_sectors = s->n_blocks*s->sectors_per_block; |
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102 | return 0; |
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103 | } |
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104 | |
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105 | static inline int cloop_read_block(BDRVCloopState *s,int block_num) |
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106 | { |
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107 | if(s->current_block != block_num) { |
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108 | int ret; |
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109 | uint32_t bytes = s->offsets[block_num+1]-s->offsets[block_num]; |
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110 | |
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111 | lseek(s->fd, s->offsets[block_num], SEEK_SET); |
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112 | ret = read(s->fd, s->compressed_block, bytes); |
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113 | if (ret != bytes) |
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114 | return -1; |
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115 | |
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116 | s->zstream.next_in = s->compressed_block; |
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117 | s->zstream.avail_in = bytes; |
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118 | s->zstream.next_out = s->uncompressed_block; |
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119 | s->zstream.avail_out = s->block_size; |
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120 | ret = inflateReset(&s->zstream); |
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121 | if(ret != Z_OK) |
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122 | return -1; |
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123 | ret = inflate(&s->zstream, Z_FINISH); |
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124 | if(ret != Z_STREAM_END || s->zstream.total_out != s->block_size) |
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125 | return -1; |
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126 | |
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127 | s->current_block = block_num; |
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128 | } |
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129 | return 0; |
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130 | } |
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131 | |
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132 | static int cloop_read(BlockDriverState *bs, int64_t sector_num, |
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133 | uint8_t *buf, int nb_sectors) |
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134 | { |
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135 | BDRVCloopState *s = bs->opaque; |
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136 | int i; |
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137 | |
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138 | for(i=0;i<nb_sectors;i++) { |
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139 | uint32_t sector_offset_in_block=((sector_num+i)%s->sectors_per_block), |
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140 | block_num=(sector_num+i)/s->sectors_per_block; |
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141 | if(cloop_read_block(s, block_num) != 0) |
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142 | return -1; |
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143 | memcpy(buf+i*512,s->uncompressed_block+sector_offset_in_block*512,512); |
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144 | } |
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145 | return 0; |
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146 | } |
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147 | |
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148 | static void cloop_close(BlockDriverState *bs) |
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149 | { |
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150 | BDRVCloopState *s = bs->opaque; |
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151 | close(s->fd); |
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152 | if(s->n_blocks>0) |
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153 | free(s->offsets); |
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154 | free(s->compressed_block); |
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155 | free(s->uncompressed_block); |
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156 | inflateEnd(&s->zstream); |
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157 | } |
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158 | |
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159 | BlockDriver bdrv_cloop = { |
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160 | "cloop", |
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161 | sizeof(BDRVCloopState), |
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162 | cloop_probe, |
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163 | cloop_open, |
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164 | cloop_read, |
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165 | NULL, |
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166 | cloop_close, |
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167 | }; |
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168 | |
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169 | |
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