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
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20 #include <freeldr.h>
  21
  22 #define NDEBUG
  23 #include <debug.h>
  24
  25 BOOL DiskGetActivePartitionEntry(ULONG DriveNumber,
  26                                  PPARTITION_TABLE_ENTRY PartitionTableEntry,
  27                                  ULONG *ActivePartition)
  28 {
  29         ULONG                   BootablePartitionCount = 0;
  30         MASTER_BOOT_RECORD      MasterBootRecord;
  31
  32         *ActivePartition = 0;
  33         // Read master boot record
  34         if (!DiskReadBootRecord(DriveNumber, 0, &MasterBootRecord))
  35         {
  36                 return FALSE;
  37         }
  38
  39         // Count the bootable partitions
  40         if (MasterBootRecord.PartitionTable[0].BootIndicator == 0x80)
  41         {
  42                 BootablePartitionCount++;
  43                 *ActivePartition = 1;
  44         }
  45         if (MasterBootRecord.PartitionTable[1].BootIndicator == 0x80)
  46         {
  47                 BootablePartitionCount++;
  48                 *ActivePartition = 2;
  49         }
  50         if (MasterBootRecord.PartitionTable[2].BootIndicator == 0x80)
  51         {
  52                 BootablePartitionCount++;
  53                 *ActivePartition = 3;
  54         }
  55         if (MasterBootRecord.PartitionTable[3].BootIndicator == 0x80)
  56         {
  57                 BootablePartitionCount++;
  58                 *ActivePartition = 4;
  59         }
  60
  61         // Make sure there was only one bootable partition
  62         if (BootablePartitionCount == 0)
  63         {
  64                 DbgPrint((DPRINT_DISK, "No bootable (active) partitions found.\n"));
  65                 return FALSE;
  66         }
  67         else if (BootablePartitionCount != 1)
  68         {
  69                 DbgPrint((DPRINT_DISK, "Too many bootable (active) partitions found.\n"));
  70                 return FALSE;
  71         }
  72
  73         // Copy the partition table entry
  74         RtlCopyMemory(PartitionTableEntry,
  75                       &MasterBootRecord.PartitionTable[*ActivePartition - 1],
  76                       sizeof(PARTITION_TABLE_ENTRY));
  77
  78         return TRUE;
  79 }
  80
  81 BOOL DiskGetPartitionEntry(ULONG DriveNumber, ULONG PartitionNumber, PPARTITION_TABLE_ENTRY PartitionTableEntry)
  82 {
  83         MASTER_BOOT_RECORD              MasterBootRecord;
  84         PARTITION_TABLE_ENTRY   ExtendedPartitionTableEntry;
  85         ULONG                                           ExtendedPartitionNumber;
  86         ULONG                                           ExtendedPartitionOffset;
  87         ULONG                                           Index;
  88
  89         // Read master boot record
  90         if (!DiskReadBootRecord(DriveNumber, 0, &MasterBootRecord))
  91         {
  92                 return FALSE;
  93         }
  94
  95         // If they are asking for a primary
  96         // partition then things are easy
  97         if (PartitionNumber < 5)
  98         {
  99                 // PartitionNumber is one-based and we need it zero-based
 100                 PartitionNumber--;
 101
 102                 // Copy the partition table entry
 103                 RtlCopyMemory(PartitionTableEntry, &MasterBootRecord.PartitionTable[PartitionNumber], sizeof(PARTITION_TABLE_ENTRY));
 104
 105                 return TRUE;
 106         }
 107         else
 108         {
 109                 // They want an extended partition entry so we will need
 110                 // to loop through all the extended partitions on the disk
 111                 // and return the one they want.
 112
 113                 ExtendedPartitionNumber = PartitionNumber - 5;
 114
 115                 // Set the initial relative starting sector to 0
 116                 // This is because extended partition starting
 117                 // sectors a numbered relative to their parent
 118                 ExtendedPartitionOffset = 0;
 119
 120                 for (Index=0; Index<=ExtendedPartitionNumber; Index++)
 121                 {
 122                         // Get the extended partition table entry
 123                         if (!DiskGetFirstExtendedPartitionEntry(&MasterBootRecord, &ExtendedPartitionTableEntry))
 124                         {
 125                                 return FALSE;
 126                         }
 127
 128                         // Adjust the relative starting sector of the partition
 129                         ExtendedPartitionTableEntry.SectorCountBeforePartition += ExtendedPartitionOffset;
 130                         if (ExtendedPartitionOffset == 0)
 131                         {
 132                                 // Set the start of the parrent extended partition
 133                                 ExtendedPartitionOffset = ExtendedPartitionTableEntry.SectorCountBeforePartition;
 134                         }
 135                         // Read the partition boot record
 136                         if (!DiskReadBootRecord(DriveNumber, ExtendedPartitionTableEntry.SectorCountBeforePartition, &MasterBootRecord))
 137                         {
 138                                 return FALSE;
 139                         }
 140
 141                         // Get the first real partition table entry
 142                         if (!DiskGetFirstPartitionEntry(&MasterBootRecord, PartitionTableEntry))
 143                         {
 144                                 return FALSE;
 145                         }
 146
 147                         // Now correct the start sector of the partition
 148                         PartitionTableEntry->SectorCountBeforePartition += ExtendedPartitionTableEntry.SectorCountBeforePartition;
 149                 }
 150
 151                 // When we get here we should have the correct entry
 152                 // already stored in PartitionTableEntry
 153                 // so just return TRUE
 154                 return TRUE;
 155         }
 156
 157 }
 158
 159 BOOL DiskGetFirstPartitionEntry(PMASTER_BOOT_RECORD MasterBootRecord, PPARTITION_TABLE_ENTRY PartitionTableEntry)
 160 {
 161         ULONG           Index;
 162
 163         for (Index=0; Index<4; Index++)
 164         {
 165                 // Check the system indicator
 166                 // If it's not an extended or unused partition
 167                 // then we're done
 168                 if ((MasterBootRecord->PartitionTable[Index].SystemIndicator != PARTITION_ENTRY_UNUSED) &&
 169                         (MasterBootRecord->PartitionTable[Index].SystemIndicator != PARTITION_EXTENDED) &&
 170                         (MasterBootRecord->PartitionTable[Index].SystemIndicator != PARTITION_XINT13_EXTENDED))
 171                 {
 172                         RtlCopyMemory(PartitionTableEntry, &MasterBootRecord->PartitionTable[Index], sizeof(PARTITION_TABLE_ENTRY));
 173                         return TRUE;
 174                 }
 175         }
 176
 177         return FALSE;
 178 }
 179
 180 BOOL DiskGetFirstExtendedPartitionEntry(PMASTER_BOOT_RECORD MasterBootRecord, PPARTITION_TABLE_ENTRY PartitionTableEntry)
 181 {
 182         ULONG           Index;
 183
 184         for (Index=0; Index<4; Index++)
 185         {
 186                 // Check the system indicator
 187                 // If it an extended partition then we're done
 188                 if ((MasterBootRecord->PartitionTable[Index].SystemIndicator == PARTITION_EXTENDED) ||
 189                         (MasterBootRecord->PartitionTable[Index].SystemIndicator == PARTITION_XINT13_EXTENDED))
 190                 {
 191                         RtlCopyMemory(PartitionTableEntry, &MasterBootRecord->PartitionTable[Index], sizeof(PARTITION_TABLE_ENTRY));
 192                         return TRUE;
 193                 }
 194         }
 195
 196         return FALSE;
 197 }
 198
 199 BOOL DiskReadBootRecord(ULONG DriveNumber, ULONGLONG LogicalSectorNumber, PMASTER_BOOT_RECORD BootRecord)
 200 {
 201         char            ErrMsg[64];
 202 #ifdef DEBUG
 203         ULONG           Index;
 204 #endif
 205
 206         // Read master boot record
 207         if (!MachDiskReadLogicalSectors(DriveNumber, LogicalSectorNumber, 1, (PVOID)DISKREADBUFFER))
 208         {
 209                 return FALSE;
 210         }
 211         RtlCopyMemory(BootRecord, (PVOID)DISKREADBUFFER, sizeof(MASTER_BOOT_RECORD));
 212
 213
 214 #ifdef DEBUG
 215
 216         DbgPrint((DPRINT_DISK, "Dumping partition table for drive 0x%x:\n", DriveNumber));
 217         DbgPrint((DPRINT_DISK, "Boot record logical start sector = %d\n", LogicalSectorNumber));
 218         DbgPrint((DPRINT_DISK, "sizeof(MASTER_BOOT_RECORD) = 0x%x.\n", sizeof(MASTER_BOOT_RECORD)));
 219
 220         for (Index=0; Index<4; Index++)
 221         {
 222                 DbgPrint((DPRINT_DISK, "-------------------------------------------\n"));
 223                 DbgPrint((DPRINT_DISK, "Partition %d\n", (Index + 1)));
 224                 DbgPrint((DPRINT_DISK, "BootIndicator: 0x%x\n", BootRecord->PartitionTable[Index].BootIndicator));
 225                 DbgPrint((DPRINT_DISK, "StartHead: 0x%x\n", BootRecord->PartitionTable[Index].StartHead));
 226                 DbgPrint((DPRINT_DISK, "StartSector (Plus 2 cylinder bits): 0x%x\n", BootRecord->PartitionTable[Index].StartSector));
 227                 DbgPrint((DPRINT_DISK, "StartCylinder: 0x%x\n", BootRecord->PartitionTable[Index].StartCylinder));
 228                 DbgPrint((DPRINT_DISK, "SystemIndicator: 0x%x\n", BootRecord->PartitionTable[Index].SystemIndicator));
 229                 DbgPrint((DPRINT_DISK, "EndHead: 0x%x\n", BootRecord->PartitionTable[Index].EndHead));
 230                 DbgPrint((DPRINT_DISK, "EndSector (Plus 2 cylinder bits): 0x%x\n", BootRecord->PartitionTable[Index].EndSector));
 231                 DbgPrint((DPRINT_DISK, "EndCylinder: 0x%x\n", BootRecord->PartitionTable[Index].EndCylinder));
 232                 DbgPrint((DPRINT_DISK, "SectorCountBeforePartition: 0x%x\n", BootRecord->PartitionTable[Index].SectorCountBeforePartition));
 233                 DbgPrint((DPRINT_DISK, "PartitionSectorCount: 0x%x\n", BootRecord->PartitionTable[Index].PartitionSectorCount));
 234         }
 235
 236 #endif // defined DEBUG
 237
 238         // Check the partition table magic value
 239         if (BootRecord->MasterBootRecordMagic != 0xaa55)
 240         {
 241                 sprintf(ErrMsg, "Invalid partition table magic 0x%x found on drive 0x%x",
 242                         BootRecord->MasterBootRecordMagic, DriveNumber);
 243                 DiskError(ErrMsg, 0);
 244                 return FALSE;
 245         }
 246
 247         return TRUE;
 248 }