1 | /* chainloader.c - boot another boot loader */ |
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2 | /* |
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3 | * GRUB -- GRand Unified Bootloader |
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4 | * Copyright (C) 2002,2004,2007,2009,2010 Free Software Foundation, Inc. |
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5 | * |
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6 | * GRUB is free software: you can redistribute it and/or modify |
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7 | * it under the terms of the GNU General Public License as published by |
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8 | * the Free Software Foundation, either version 3 of the License, or |
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9 | * (at your option) any later version. |
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10 | * |
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11 | * GRUB is distributed in the hope that it will be useful, |
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | * GNU General Public License for more details. |
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15 | * |
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16 | * You should have received a copy of the GNU General Public License |
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17 | * along with GRUB. If not, see <http://www.gnu.org/licenses/>. |
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18 | */ |
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19 | |
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20 | #include <grub/loader.h> |
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21 | #include <grub/machine/chainloader.h> |
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22 | #include <grub/machine/memory.h> |
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23 | #include <grub/file.h> |
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24 | #include <grub/err.h> |
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25 | #include <grub/device.h> |
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26 | #include <grub/disk.h> |
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27 | #include <grub/misc.h> |
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28 | #include <grub/types.h> |
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29 | #include <grub/partition.h> |
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30 | #include <grub/memory.h> |
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31 | #include <grub/dl.h> |
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32 | #include <grub/command.h> |
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33 | #include <grub/msdos_partition.h> |
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34 | #include <grub/machine/biosnum.h> |
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35 | #include <grub/cpu/floppy.h> |
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36 | #include <grub/i18n.h> |
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37 | #include <grub/video.h> |
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38 | #include <grub/mm.h> |
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39 | #include <grub/fat.h> |
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40 | #include <grub/ntfs.h> |
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41 | #include <grub/i386/relocator.h> |
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42 | |
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43 | GRUB_MOD_LICENSE ("GPLv3+"); |
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44 | |
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45 | static grub_dl_t my_mod; |
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46 | static int boot_drive; |
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47 | static grub_addr_t boot_part_addr; |
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48 | static struct grub_relocator *rel; |
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49 | |
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50 | typedef enum |
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51 | { |
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52 | GRUB_CHAINLOADER_FORCE = 0x1, |
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53 | GRUB_CHAINLOADER_BPB = 0x2, |
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54 | } grub_chainloader_flags_t; |
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55 | |
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56 | static grub_err_t |
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57 | grub_chainloader_boot (void) |
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58 | { |
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59 | struct grub_relocator16_state state = { |
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60 | .edx = boot_drive, |
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61 | .esi = boot_part_addr, |
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62 | .ds = 0, |
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63 | .es = 0, |
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64 | .fs = 0, |
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65 | .gs = 0, |
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66 | .ss = 0, |
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67 | .cs = 0, |
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68 | .sp = GRUB_MEMORY_MACHINE_BOOT_LOADER_ADDR, |
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69 | .ip = GRUB_MEMORY_MACHINE_BOOT_LOADER_ADDR, |
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70 | .a20 = 0 |
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71 | }; |
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72 | grub_video_set_mode ("text", 0, 0); |
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73 | |
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74 | return grub_relocator16_boot (rel, state); |
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75 | } |
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76 | |
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77 | static grub_err_t |
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78 | grub_chainloader_unload (void) |
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79 | { |
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80 | grub_relocator_unload (rel); |
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81 | rel = NULL; |
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82 | grub_dl_unref (my_mod); |
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83 | return GRUB_ERR_NONE; |
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84 | } |
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85 | |
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86 | void |
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87 | grub_chainloader_patch_bpb (void *bs, grub_device_t dev, grub_uint8_t dl) |
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88 | { |
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89 | grub_uint32_t part_start = 0; |
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90 | if (dev && dev->disk) |
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91 | part_start = grub_partition_get_start (dev->disk->partition); |
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92 | if (grub_memcmp ((char *) &((struct grub_ntfs_bpb *) bs)->oem_name, |
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93 | "NTFS", 4) == 0) |
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94 | { |
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95 | struct grub_ntfs_bpb *bpb = (struct grub_ntfs_bpb *) bs; |
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96 | bpb->num_hidden_sectors = grub_cpu_to_le32 (part_start); |
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97 | bpb->bios_drive = dl; |
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98 | return; |
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99 | } |
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100 | |
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101 | do |
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102 | { |
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103 | struct grub_fat_bpb *bpb = (struct grub_fat_bpb *) bs; |
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104 | if (grub_strncmp((const char *) bpb->version_specific.fat12_or_fat16.fstype, "FAT12", 5) |
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105 | && grub_strncmp((const char *) bpb->version_specific.fat12_or_fat16.fstype, "FAT16", 5) |
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106 | && grub_strncmp((const char *) bpb->version_specific.fat32.fstype, "FAT32", 5)) |
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107 | break; |
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108 | |
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109 | if (grub_le_to_cpu16 (bpb->bytes_per_sector) < 512 |
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110 | || (grub_le_to_cpu16 (bpb->bytes_per_sector) |
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111 | & (grub_le_to_cpu16 (bpb->bytes_per_sector) - 1))) |
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112 | break; |
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113 | |
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114 | if (bpb->sectors_per_cluster == 0 |
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115 | || (bpb->sectors_per_cluster & (bpb->sectors_per_cluster - 1))) |
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116 | break; |
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117 | |
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118 | if (bpb->num_reserved_sectors == 0) |
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119 | break; |
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120 | if (bpb->num_total_sectors_16 == 0 || bpb->num_total_sectors_32 == 0) |
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121 | break; |
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122 | |
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123 | if (bpb->num_fats == 0) |
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124 | break; |
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125 | |
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126 | if (bpb->sectors_per_fat_16) |
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127 | { |
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128 | bpb->num_hidden_sectors = grub_cpu_to_le32 (part_start); |
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129 | bpb->version_specific.fat12_or_fat16.num_ph_drive = dl; |
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130 | return; |
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131 | } |
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132 | if (bpb->version_specific.fat32.sectors_per_fat_32) |
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133 | { |
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134 | bpb->num_hidden_sectors = grub_cpu_to_le32 (part_start); |
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135 | bpb->version_specific.fat32.num_ph_drive = dl; |
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136 | return; |
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137 | } |
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138 | break; |
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139 | } |
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140 | while (0); |
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141 | } |
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142 | |
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143 | static void |
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144 | grub_chainloader_cmd (const char *filename, grub_chainloader_flags_t flags) |
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145 | { |
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146 | grub_file_t file = 0; |
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147 | grub_uint16_t signature; |
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148 | grub_device_t dev; |
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149 | int drive = -1; |
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150 | grub_addr_t part_addr = 0; |
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151 | grub_uint8_t *bs, *ptable; |
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152 | |
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153 | rel = grub_relocator_new (); |
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154 | if (!rel) |
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155 | goto fail; |
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156 | |
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157 | grub_dl_ref (my_mod); |
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158 | |
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159 | grub_file_filter_disable_compression (); |
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160 | file = grub_file_open (filename); |
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161 | if (! file) |
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162 | goto fail; |
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163 | |
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164 | { |
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165 | grub_relocator_chunk_t ch; |
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166 | grub_err_t err; |
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167 | |
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168 | err = grub_relocator_alloc_chunk_addr (rel, &ch, 0x7C00, |
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169 | GRUB_DISK_SECTOR_SIZE); |
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170 | if (err) |
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171 | goto fail; |
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172 | bs = get_virtual_current_address (ch); |
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173 | err = grub_relocator_alloc_chunk_addr (rel, &ch, |
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174 | GRUB_MEMORY_MACHINE_PART_TABLE_ADDR, |
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175 | 64); |
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176 | if (err) |
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177 | goto fail; |
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178 | ptable = get_virtual_current_address (ch); |
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179 | } |
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180 | |
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181 | /* Read the first block. */ |
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182 | if (grub_file_read (file, bs, GRUB_DISK_SECTOR_SIZE) |
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183 | != GRUB_DISK_SECTOR_SIZE) |
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184 | { |
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185 | if (!grub_errno) |
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186 | grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"), |
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187 | filename); |
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188 | |
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189 | goto fail; |
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190 | } |
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191 | |
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192 | /* Check the signature. */ |
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193 | signature = *((grub_uint16_t *) (bs + GRUB_DISK_SECTOR_SIZE - 2)); |
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194 | if (signature != grub_le_to_cpu16 (0xaa55) |
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195 | && ! (flags & GRUB_CHAINLOADER_FORCE)) |
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196 | { |
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197 | grub_error (GRUB_ERR_BAD_OS, "invalid signature"); |
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198 | goto fail; |
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199 | } |
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200 | |
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201 | grub_file_close (file); |
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202 | |
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203 | /* Obtain the partition table from the root device. */ |
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204 | drive = grub_get_root_biosnumber (); |
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205 | dev = grub_device_open (0); |
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206 | if (dev && dev->disk && dev->disk->partition) |
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207 | { |
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208 | grub_disk_t disk = dev->disk; |
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209 | |
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210 | if (disk) |
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211 | { |
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212 | grub_partition_t p = disk->partition; |
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213 | |
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214 | if (p && grub_strcmp (p->partmap->name, "msdos") == 0) |
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215 | { |
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216 | disk->partition = p->parent; |
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217 | grub_disk_read (disk, p->offset, 446, 64, ptable); |
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218 | part_addr = (GRUB_MEMORY_MACHINE_PART_TABLE_ADDR |
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219 | + (p->index << 4)); |
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220 | disk->partition = p; |
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221 | } |
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222 | } |
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223 | } |
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224 | |
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225 | if (flags & GRUB_CHAINLOADER_BPB) |
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226 | grub_chainloader_patch_bpb ((void *) 0x7C00, dev, drive); |
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227 | |
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228 | if (dev) |
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229 | grub_device_close (dev); |
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230 | |
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231 | /* Ignore errors. Perhaps it's not fatal. */ |
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232 | grub_errno = GRUB_ERR_NONE; |
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233 | |
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234 | boot_drive = drive; |
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235 | boot_part_addr = part_addr; |
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236 | |
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237 | grub_loader_set (grub_chainloader_boot, grub_chainloader_unload, 1); |
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238 | return; |
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239 | |
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240 | fail: |
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241 | |
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242 | if (file) |
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243 | grub_file_close (file); |
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244 | |
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245 | grub_dl_unref (my_mod); |
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246 | } |
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247 | |
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248 | static grub_err_t |
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249 | grub_cmd_chainloader (grub_command_t cmd __attribute__ ((unused)), |
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250 | int argc, char *argv[]) |
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251 | { |
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252 | grub_chainloader_flags_t flags = 0; |
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253 | |
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254 | while (argc > 0) |
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255 | { |
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256 | if (grub_strcmp (argv[0], "--force") == 0) |
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257 | { |
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258 | flags |= GRUB_CHAINLOADER_FORCE; |
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259 | argc--; |
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260 | argv++; |
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261 | continue; |
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262 | } |
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263 | if (grub_strcmp (argv[0], "--bpb") == 0) |
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264 | { |
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265 | flags |= GRUB_CHAINLOADER_BPB; |
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266 | argc--; |
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267 | argv++; |
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268 | continue; |
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269 | } |
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270 | break; |
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271 | } |
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272 | |
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273 | if (argc == 0) |
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274 | return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected")); |
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275 | |
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276 | grub_chainloader_cmd (argv[0], flags); |
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277 | |
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278 | return grub_errno; |
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279 | } |
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280 | |
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281 | static grub_command_t cmd; |
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282 | |
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283 | GRUB_MOD_INIT(chainloader) |
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284 | { |
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285 | cmd = grub_register_command ("chainloader", grub_cmd_chainloader, |
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286 | N_("[--force|--bpb] FILE"), |
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287 | N_("Load another boot loader.")); |
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288 | my_mod = mod; |
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289 | } |
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290 | |
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291 | GRUB_MOD_FINI(chainloader) |
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292 | { |
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293 | grub_unregister_command (cmd); |
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294 | } |
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