Eltorito.c 6.4 KB

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  1. /** @file
  2. Routines supporting partition discovery and
  3. logical device reading
  4. Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
  5. SPDX-License-Identifier: BSD-2-Clause-Patent
  6. **/
  7. #include <IndustryStandard/ElTorito.h>
  8. #include "FatLitePeim.h"
  9. /**
  10. This function finds Eltorito partitions. Main algorithm
  11. is ported from DXE partition driver.
  12. @param[in] PrivateData The global memory map
  13. @param[in] ParentBlockDevNo The parent block device
  14. @retval TRUE New partitions are detected and logical block devices
  15. are added to block device array
  16. @retval FALSE No new partitions are added
  17. **/
  18. BOOLEAN
  19. FatFindEltoritoPartitions (
  20. IN PEI_FAT_PRIVATE_DATA *PrivateData,
  21. IN UINTN ParentBlockDevNo
  22. )
  23. {
  24. EFI_STATUS Status;
  25. BOOLEAN Found;
  26. PEI_FAT_BLOCK_DEVICE *BlockDev;
  27. PEI_FAT_BLOCK_DEVICE *ParentBlockDev;
  28. UINT32 VolDescriptorLba;
  29. UINT32 Lba;
  30. CDROM_VOLUME_DESCRIPTOR *VolDescriptor;
  31. ELTORITO_CATALOG *Catalog;
  32. UINTN Check;
  33. UINTN Index;
  34. UINTN MaxIndex;
  35. UINT16 *CheckBuffer;
  36. UINT32 SubBlockSize;
  37. UINT32 SectorCount;
  38. UINT32 VolSpaceSize;
  39. if (ParentBlockDevNo > PEI_FAT_MAX_BLOCK_DEVICE - 1) {
  40. return FALSE;
  41. }
  42. Found = FALSE;
  43. ParentBlockDev = &(PrivateData->BlockDevice[ParentBlockDevNo]);
  44. VolSpaceSize = 0;
  45. //
  46. // CD_ROM has the fixed block size as 2048 bytes
  47. //
  48. if (ParentBlockDev->BlockSize != 2048) {
  49. return FALSE;
  50. }
  51. VolDescriptor = (CDROM_VOLUME_DESCRIPTOR *)PrivateData->BlockData;
  52. Catalog = (ELTORITO_CATALOG *)VolDescriptor;
  53. //
  54. // the ISO-9660 volume descriptor starts at 32k on the media
  55. // and CD_ROM has the fixed block size as 2048 bytes, so...
  56. //
  57. VolDescriptorLba = 15;
  58. //
  59. // ((16*2048) / Media->BlockSize) - 1;
  60. //
  61. // Loop: handle one volume descriptor per time
  62. //
  63. while (TRUE) {
  64. VolDescriptorLba += 1;
  65. if (VolDescriptorLba > ParentBlockDev->LastBlock) {
  66. //
  67. // We are pointing past the end of the device so exit
  68. //
  69. break;
  70. }
  71. Status = FatReadBlock (
  72. PrivateData,
  73. ParentBlockDevNo,
  74. VolDescriptorLba,
  75. ParentBlockDev->BlockSize,
  76. VolDescriptor
  77. );
  78. if (EFI_ERROR (Status)) {
  79. break;
  80. }
  81. //
  82. // Check for valid volume descriptor signature
  83. //
  84. if ((VolDescriptor->Unknown.Type == CDVOL_TYPE_END) ||
  85. (CompareMem (VolDescriptor->Unknown.Id, CDVOL_ID, sizeof (VolDescriptor->Unknown.Id)) != 0)
  86. )
  87. {
  88. //
  89. // end of Volume descriptor list
  90. //
  91. break;
  92. }
  93. //
  94. // Read the Volume Space Size from Primary Volume Descriptor 81-88 byte
  95. //
  96. if (VolDescriptor->Unknown.Type == CDVOL_TYPE_CODED) {
  97. VolSpaceSize = VolDescriptor->PrimaryVolume.VolSpaceSize[1];
  98. }
  99. //
  100. // Is it an El Torito volume descriptor?
  101. //
  102. if (CompareMem (
  103. VolDescriptor->BootRecordVolume.SystemId,
  104. CDVOL_ELTORITO_ID,
  105. sizeof (CDVOL_ELTORITO_ID) - 1
  106. ) != 0)
  107. {
  108. continue;
  109. }
  110. //
  111. // Read in the boot El Torito boot catalog
  112. //
  113. Lba = UNPACK_INT32 (VolDescriptor->BootRecordVolume.EltCatalog);
  114. if (Lba > ParentBlockDev->LastBlock) {
  115. continue;
  116. }
  117. Status = FatReadBlock (
  118. PrivateData,
  119. ParentBlockDevNo,
  120. Lba,
  121. ParentBlockDev->BlockSize,
  122. Catalog
  123. );
  124. if (EFI_ERROR (Status)) {
  125. continue;
  126. }
  127. //
  128. // We don't care too much about the Catalog header's contents, but we do want
  129. // to make sure it looks like a Catalog header
  130. //
  131. if ((Catalog->Catalog.Indicator != ELTORITO_ID_CATALOG) || (Catalog->Catalog.Id55AA != 0xAA55)) {
  132. continue;
  133. }
  134. Check = 0;
  135. CheckBuffer = (UINT16 *)Catalog;
  136. for (Index = 0; Index < sizeof (ELTORITO_CATALOG) / sizeof (UINT16); Index += 1) {
  137. Check += CheckBuffer[Index];
  138. }
  139. if ((Check & 0xFFFF) != 0) {
  140. continue;
  141. }
  142. MaxIndex = ParentBlockDev->BlockSize / sizeof (ELTORITO_CATALOG);
  143. for (Index = 1; Index < MaxIndex; Index += 1) {
  144. //
  145. // Next entry
  146. //
  147. Catalog += 1;
  148. //
  149. // Check this entry
  150. //
  151. if ((Catalog->Boot.Indicator != ELTORITO_ID_SECTION_BOOTABLE) || (Catalog->Boot.Lba == 0)) {
  152. continue;
  153. }
  154. SubBlockSize = 512;
  155. SectorCount = Catalog->Boot.SectorCount;
  156. switch (Catalog->Boot.MediaType) {
  157. case ELTORITO_NO_EMULATION:
  158. SubBlockSize = ParentBlockDev->BlockSize;
  159. SectorCount = Catalog->Boot.SectorCount;
  160. break;
  161. case ELTORITO_HARD_DISK:
  162. break;
  163. case ELTORITO_12_DISKETTE:
  164. SectorCount = 0x50 * 0x02 * 0x0F;
  165. break;
  166. case ELTORITO_14_DISKETTE:
  167. SectorCount = 0x50 * 0x02 * 0x12;
  168. break;
  169. case ELTORITO_28_DISKETTE:
  170. SectorCount = 0x50 * 0x02 * 0x24;
  171. break;
  172. default:
  173. SectorCount = 0;
  174. SubBlockSize = ParentBlockDev->BlockSize;
  175. break;
  176. }
  177. if (SectorCount < 2) {
  178. SectorCount = (VolSpaceSize > ParentBlockDev->LastBlock + 1) ? (UINT32)(ParentBlockDev->LastBlock - Catalog->Boot.Lba + 1) : (UINT32)(VolSpaceSize - Catalog->Boot.Lba);
  179. }
  180. //
  181. // Register this partition
  182. //
  183. if (PrivateData->BlockDeviceCount < PEI_FAT_MAX_BLOCK_DEVICE) {
  184. Found = TRUE;
  185. BlockDev = &(PrivateData->BlockDevice[PrivateData->BlockDeviceCount]);
  186. BlockDev->BlockSize = SubBlockSize;
  187. BlockDev->LastBlock = SectorCount - 1;
  188. BlockDev->IoAlign = ParentBlockDev->IoAlign;
  189. BlockDev->Logical = TRUE;
  190. BlockDev->PartitionChecked = FALSE;
  191. BlockDev->StartingPos = MultU64x32 (Catalog->Boot.Lba, ParentBlockDev->BlockSize);
  192. BlockDev->ParentDevNo = ParentBlockDevNo;
  193. PrivateData->BlockDeviceCount++;
  194. }
  195. }
  196. }
  197. ParentBlockDev->PartitionChecked = TRUE;
  198. return Found;
  199. }