reactos/boot/freeldr/freeldr/disk/partition.c

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 1998-2003  Brian Palmer  <brianp@sginet.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License along
  16  *  with this program; if not, write to the Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <freeldr.h>
  21 #include <debug.h>
  22
  23 BOOLEAN DiskGetActivePartitionEntry(ULONG DriveNumber,
  24                                  PPARTITION_TABLE_ENTRY PartitionTableEntry,
  25                                  ULONG *ActivePartition)
  26 {
  27         ULONG                   BootablePartitionCount = 0;
  28         MASTER_BOOT_RECORD      MasterBootRecord;
  29
  30         *ActivePartition = 0;
  31         // Read master boot record
  32         if (!DiskReadBootRecord(DriveNumber, 0, &MasterBootRecord))
  33         {
  34                 return FALSE;
  35         }
  36
  37         // Count the bootable partitions
  38         if (MasterBootRecord.PartitionTable[0].BootIndicator == 0x80)
  39         {
  40                 BootablePartitionCount++;
  41                 *ActivePartition = 1;
  42         }
  43         if (MasterBootRecord.PartitionTable[1].BootIndicator == 0x80)
  44         {
  45                 BootablePartitionCount++;
  46                 *ActivePartition = 2;
  47         }
  48         if (MasterBootRecord.PartitionTable[2].BootIndicator == 0x80)
  49         {
  50                 BootablePartitionCount++;
  51                 *ActivePartition = 3;
  52         }
  53         if (MasterBootRecord.PartitionTable[3].BootIndicator == 0x80)
  54         {
  55                 BootablePartitionCount++;
  56                 *ActivePartition = 4;
  57         }
  58
  59         // Make sure there was only one bootable partition
  60         if (BootablePartitionCount == 0)
  61         {
  62                 DPRINTM(DPRINT_DISK, "No bootable (active) partitions found.\n");
  63                 return FALSE;
  64         }
  65         else if (BootablePartitionCount != 1)
  66         {
  67                 DPRINTM(DPRINT_DISK, "Too many bootable (active) partitions found.\n");
  68                 return FALSE;
  69         }
  70
  71         // Copy the partition table entry
  72         RtlCopyMemory(PartitionTableEntry,
  73                       &MasterBootRecord.PartitionTable[*ActivePartition - 1],
  74                       sizeof(PARTITION_TABLE_ENTRY));
  75
  76         return TRUE;
  77 }
  78
  79 BOOLEAN DiskGetPartitionEntry(ULONG DriveNumber, ULONG PartitionNumber, PPARTITION_TABLE_ENTRY PartitionTableEntry)
  80 {
  81         MASTER_BOOT_RECORD              MasterBootRecord;
  82         PARTITION_TABLE_ENTRY   ExtendedPartitionTableEntry;
  83         ULONG                                           ExtendedPartitionNumber;
  84         ULONG                                           ExtendedPartitionOffset;
  85         ULONG                                           Index;
  86
  87         // Read master boot record
  88         if (!DiskReadBootRecord(DriveNumber, 0, &MasterBootRecord))
  89         {
  90                 return FALSE;
  91         }
  92
  93         // If they are asking for a primary
  94         // partition then things are easy
  95         if (PartitionNumber < 5)
  96         {
  97                 // PartitionNumber is one-based and we need it zero-based
  98                 PartitionNumber--;
  99
 100                 // Copy the partition table entry
 101                 RtlCopyMemory(PartitionTableEntry, &MasterBootRecord.PartitionTable[PartitionNumber], sizeof(PARTITION_TABLE_ENTRY));
 102
 103                 return TRUE;
 104         }
 105         else
 106         {
 107                 // They want an extended partition entry so we will need
 108                 // to loop through all the extended partitions on the disk
 109                 // and return the one they want.
 110
 111                 ExtendedPartitionNumber = PartitionNumber - 5;
 112
 113                 // Set the initial relative starting sector to 0
 114                 // This is because extended partition starting
 115                 // sectors a numbered relative to their parent
 116                 ExtendedPartitionOffset = 0;
 117
 118                 for (Index=0; Index<=ExtendedPartitionNumber; Index++)
 119                 {
 120                         // Get the extended partition table entry
 121                         if (!DiskGetFirstExtendedPartitionEntry(&MasterBootRecord, &ExtendedPartitionTableEntry))
 122                         {
 123                                 return FALSE;
 124                         }
 125
 126                         // Adjust the relative starting sector of the partition
 127                         ExtendedPartitionTableEntry.SectorCountBeforePartition += ExtendedPartitionOffset;
 128                         if (ExtendedPartitionOffset == 0)
 129                         {
 130                                 // Set the start of the parrent extended partition
 131                                 ExtendedPartitionOffset = ExtendedPartitionTableEntry.SectorCountBeforePartition;
 132                         }
 133                         // Read the partition boot record
 134                         if (!DiskReadBootRecord(DriveNumber, ExtendedPartitionTableEntry.SectorCountBeforePartition, &MasterBootRecord))
 135                         {
 136                                 return FALSE;
 137                         }
 138
 139                         // Get the first real partition table entry
 140                         if (!DiskGetFirstPartitionEntry(&MasterBootRecord, PartitionTableEntry))
 141                         {
 142                                 return FALSE;
 143                         }
 144
 145                         // Now correct the start sector of the partition
 146                         PartitionTableEntry->SectorCountBeforePartition += ExtendedPartitionTableEntry.SectorCountBeforePartition;
 147                 }
 148
 149                 // When we get here we should have the correct entry
 150                 // already stored in PartitionTableEntry
 151                 // so just return TRUE
 152                 return TRUE;
 153         }
 154
 155 }
 156
 157 BOOLEAN DiskGetFirstPartitionEntry(PMASTER_BOOT_RECORD MasterBootRecord, PPARTITION_TABLE_ENTRY PartitionTableEntry)
 158 {
 159         ULONG           Index;
 160
 161         for (Index=0; Index<4; Index++)
 162         {
 163                 // Check the system indicator
 164                 // If it's not an extended or unused partition
 165                 // then we're done
 166                 if ((MasterBootRecord->PartitionTable[Index].SystemIndicator != PARTITION_ENTRY_UNUSED) &&
 167                         (MasterBootRecord->PartitionTable[Index].SystemIndicator != PARTITION_EXTENDED) &&
 168                         (MasterBootRecord->PartitionTable[Index].SystemIndicator != PARTITION_XINT13_EXTENDED))
 169                 {
 170                         RtlCopyMemory(PartitionTableEntry, &MasterBootRecord->PartitionTable[Index], sizeof(PARTITION_TABLE_ENTRY));
 171                         return TRUE;
 172                 }
 173         }
 174
 175         return FALSE;
 176 }
 177
 178 BOOLEAN DiskGetFirstExtendedPartitionEntry(PMASTER_BOOT_RECORD MasterBootRecord, PPARTITION_TABLE_ENTRY PartitionTableEntry)
 179 {
 180         ULONG           Index;
 181
 182         for (Index=0; Index<4; Index++)
 183         {
 184                 // Check the system indicator
 185                 // If it an extended partition then we're done
 186                 if ((MasterBootRecord->PartitionTable[Index].SystemIndicator == PARTITION_EXTENDED) ||
 187                         (MasterBootRecord->PartitionTable[Index].SystemIndicator == PARTITION_XINT13_EXTENDED))
 188                 {
 189                         RtlCopyMemory(PartitionTableEntry, &MasterBootRecord->PartitionTable[Index], sizeof(PARTITION_TABLE_ENTRY));
 190                         return TRUE;
 191                 }
 192         }
 193
 194         return FALSE;
 195 }
 196
 197 BOOLEAN DiskReadBootRecord(ULONG DriveNumber, ULONGLONG LogicalSectorNumber, PMASTER_BOOT_RECORD BootRecord)
 198 {
 199         char            ErrMsg[64];
 200         ULONG           Index;
 201
 202         // Read master boot record
 203         if (!MachDiskReadLogicalSectors(DriveNumber, LogicalSectorNumber, 1, (PVOID)DISKREADBUFFER))
 204         {
 205                 return FALSE;
 206         }
 207         RtlCopyMemory(BootRecord, (PVOID)DISKREADBUFFER, sizeof(MASTER_BOOT_RECORD));
 208
 209
 210         DPRINTM(DPRINT_DISK, "Dumping partition table for drive 0x%x:\n", DriveNumber);
 211         DPRINTM(DPRINT_DISK, "Boot record logical start sector = %d\n", LogicalSectorNumber);
 212         DPRINTM(DPRINT_DISK, "sizeof(MASTER_BOOT_RECORD) = 0x%x.\n", sizeof(MASTER_BOOT_RECORD));
 213
 214         for (Index=0; Index<4; Index++)
 215         {
 216                 DPRINTM(DPRINT_DISK, "-------------------------------------------\n");
 217                 DPRINTM(DPRINT_DISK, "Partition %d\n", (Index + 1));
 218                 DPRINTM(DPRINT_DISK, "BootIndicator: 0x%x\n", BootRecord->PartitionTable[Index].BootIndicator);
 219                 DPRINTM(DPRINT_DISK, "StartHead: 0x%x\n", BootRecord->PartitionTable[Index].StartHead);
 220                 DPRINTM(DPRINT_DISK, "StartSector (Plus 2 cylinder bits): 0x%x\n", BootRecord->PartitionTable[Index].StartSector);
 221                 DPRINTM(DPRINT_DISK, "StartCylinder: 0x%x\n", BootRecord->PartitionTable[Index].StartCylinder);
 222                 DPRINTM(DPRINT_DISK, "SystemIndicator: 0x%x\n", BootRecord->PartitionTable[Index].SystemIndicator);
 223                 DPRINTM(DPRINT_DISK, "EndHead: 0x%x\n", BootRecord->PartitionTable[Index].EndHead);
 224                 DPRINTM(DPRINT_DISK, "EndSector (Plus 2 cylinder bits): 0x%x\n", BootRecord->PartitionTable[Index].EndSector);
 225                 DPRINTM(DPRINT_DISK, "EndCylinder: 0x%x\n", BootRecord->PartitionTable[Index].EndCylinder);
 226                 DPRINTM(DPRINT_DISK, "SectorCountBeforePartition: 0x%x\n", BootRecord->PartitionTable[Index].SectorCountBeforePartition);
 227                 DPRINTM(DPRINT_DISK, "PartitionSectorCount: 0x%x\n", BootRecord->PartitionTable[Index].PartitionSectorCount);
 228         }
 229
 230         // Check the partition table magic value
 231         if (BootRecord->MasterBootRecordMagic != 0xaa55)
 232         {
 233                 sprintf(ErrMsg, "Invalid partition table magic 0x%x found on drive 0x%lx",
 234                         BootRecord->MasterBootRecordMagic, DriveNumber);
 235                 DiskError(ErrMsg, 0);
 236                 return FALSE;
 237         }
 238
 239         return TRUE;
 240 }