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. // end of Volume descriptor list
  89. //
  90. break;
  91. }
  92. //
  93. // Read the Volume Space Size from Primary Volume Descriptor 81-88 byte
  94. //
  95. if (VolDescriptor->Unknown.Type == CDVOL_TYPE_CODED) {
  96. VolSpaceSize = VolDescriptor->PrimaryVolume.VolSpaceSize[1];
  97. }
  98. //
  99. // Is it an El Torito volume descriptor?
  100. //
  101. if (CompareMem (
  102. VolDescriptor->BootRecordVolume.SystemId,
  103. CDVOL_ELTORITO_ID,
  104. sizeof (CDVOL_ELTORITO_ID) - 1
  105. ) != 0) {
  106. continue;
  107. }
  108. //
  109. // Read in the boot El Torito boot catalog
  110. //
  111. Lba = UNPACK_INT32 (VolDescriptor->BootRecordVolume.EltCatalog);
  112. if (Lba > ParentBlockDev->LastBlock) {
  113. continue;
  114. }
  115. Status = FatReadBlock (
  116. PrivateData,
  117. ParentBlockDevNo,
  118. Lba,
  119. ParentBlockDev->BlockSize,
  120. Catalog
  121. );
  122. if (EFI_ERROR (Status)) {
  123. continue;
  124. }
  125. //
  126. // We don't care too much about the Catalog header's contents, but we do want
  127. // to make sure it looks like a Catalog header
  128. //
  129. if (Catalog->Catalog.Indicator != ELTORITO_ID_CATALOG || Catalog->Catalog.Id55AA != 0xAA55) {
  130. continue;
  131. }
  132. Check = 0;
  133. CheckBuffer = (UINT16 *) Catalog;
  134. for (Index = 0; Index < sizeof (ELTORITO_CATALOG) / sizeof (UINT16); Index += 1) {
  135. Check += CheckBuffer[Index];
  136. }
  137. if ((Check & 0xFFFF) != 0) {
  138. continue;
  139. }
  140. MaxIndex = ParentBlockDev->BlockSize / sizeof (ELTORITO_CATALOG);
  141. for (Index = 1; Index < MaxIndex; Index += 1) {
  142. //
  143. // Next entry
  144. //
  145. Catalog += 1;
  146. //
  147. // Check this entry
  148. //
  149. if (Catalog->Boot.Indicator != ELTORITO_ID_SECTION_BOOTABLE || Catalog->Boot.Lba == 0) {
  150. continue;
  151. }
  152. SubBlockSize = 512;
  153. SectorCount = Catalog->Boot.SectorCount;
  154. switch (Catalog->Boot.MediaType) {
  155. case ELTORITO_NO_EMULATION:
  156. SubBlockSize = ParentBlockDev->BlockSize;
  157. SectorCount = Catalog->Boot.SectorCount;
  158. break;
  159. case ELTORITO_HARD_DISK:
  160. break;
  161. case ELTORITO_12_DISKETTE:
  162. SectorCount = 0x50 * 0x02 * 0x0F;
  163. break;
  164. case ELTORITO_14_DISKETTE:
  165. SectorCount = 0x50 * 0x02 * 0x12;
  166. break;
  167. case ELTORITO_28_DISKETTE:
  168. SectorCount = 0x50 * 0x02 * 0x24;
  169. break;
  170. default:
  171. SectorCount = 0;
  172. SubBlockSize = ParentBlockDev->BlockSize;
  173. break;
  174. }
  175. if (SectorCount < 2) {
  176. SectorCount = (VolSpaceSize > ParentBlockDev->LastBlock + 1) ? (UINT32) (ParentBlockDev->LastBlock - Catalog->Boot.Lba + 1) : (UINT32) (VolSpaceSize - Catalog->Boot.Lba);
  177. }
  178. //
  179. // Register this partition
  180. //
  181. if (PrivateData->BlockDeviceCount < PEI_FAT_MAX_BLOCK_DEVICE) {
  182. Found = TRUE;
  183. BlockDev = &(PrivateData->BlockDevice[PrivateData->BlockDeviceCount]);
  184. BlockDev->BlockSize = SubBlockSize;
  185. BlockDev->LastBlock = SectorCount - 1;
  186. BlockDev->IoAlign = ParentBlockDev->IoAlign;
  187. BlockDev->Logical = TRUE;
  188. BlockDev->PartitionChecked = FALSE;
  189. BlockDev->StartingPos = MultU64x32 (Catalog->Boot.Lba, ParentBlockDev->BlockSize);
  190. BlockDev->ParentDevNo = ParentBlockDevNo;
  191. PrivateData->BlockDeviceCount++;
  192. }
  193. }
  194. }
  195. ParentBlockDev->PartitionChecked = TRUE;
  196. return Found;
  197. }