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 #include <disk.h>
  22 #include <rtl.h>
  23 #include <mm.h>
  24 #include <debug.h>
  25 #include <arch.h>
  26 #include <machine.h>
  27
  28
  29 BOOL DiskGetActivePartitionEntry(U32 DriveNumber, PPARTITION_TABLE_ENTRY PartitionTableEntry)
  30 {
  31         U32                                     BootablePartitionCount = 0;
  32         MASTER_BOOT_RECORD      MasterBootRecord;
  33
  34         // Read master boot record
  35         if (!DiskReadBootRecord(DriveNumber, 0, &MasterBootRecord))
  36         {
  37                 return FALSE;
  38         }
  39
  40         // Count the bootable partitions
  41         if (MasterBootRecord.PartitionTable[0].BootIndicator == 0x80)
  42         {
  43                 BootablePartitionCount++;
  44                 BootPartition = 0;
  45         }
  46         if (MasterBootRecord.PartitionTable[1].BootIndicator == 0x80)
  47         {
  48                 BootablePartitionCount++;
  49                 BootPartition = 1;
  50         }
  51         if (MasterBootRecord.PartitionTable[2].BootIndicator == 0x80)
  52         {
  53                 BootablePartitionCount++;
  54                 BootPartition = 2;
  55         }
  56         if (MasterBootRecord.PartitionTable[3].BootIndicator == 0x80)
  57         {
  58                 BootablePartitionCount++;
  59                 BootPartition = 3;
  60         }
  61
  62         // Make sure there was only one bootable partition
  63         if (BootablePartitionCount == 0)
  64         {
  65                 DiskError("No bootable (active) partitions found.", 0);
  66                 return FALSE;
  67         }
  68         else if (BootablePartitionCount != 1)
  69         {
  70                 DiskError("Too many bootable (active) partitions found.", 0);
  71                 return FALSE;
  72         }
  73
  74         // Copy the partition table entry
  75         RtlCopyMemory(PartitionTableEntry, &MasterBootRecord.PartitionTable[BootPartition], sizeof(PARTITION_TABLE_ENTRY));
  76
  77         return TRUE;
  78 }
  79
  80 BOOL DiskGetPartitionEntry(U32 DriveNumber, U32 PartitionNumber, PPARTITION_TABLE_ENTRY PartitionTableEntry)
  81 {
  82         MASTER_BOOT_RECORD              MasterBootRecord;
  83         PARTITION_TABLE_ENTRY   ExtendedPartitionTableEntry;
  84         U32                                             ExtendedPartitionNumber;
  85         U32                                             ExtendedPartitionOffset;
  86         U32                                             Index;
  87
  88         // Read master boot record
  89         if (!DiskReadBootRecord(DriveNumber, 0, &MasterBootRecord))
  90         {
  91                 return FALSE;
  92         }
  93
  94         // If they are asking for a primary
  95         // partition then things are easy
  96         if (PartitionNumber < 5)
  97         {
  98                 // PartitionNumber is one-based and we need it zero-based
  99                 PartitionNumber--;
 100
 101                 // Copy the partition table entry
 102                 RtlCopyMemory(PartitionTableEntry, &MasterBootRecord.PartitionTable[PartitionNumber], sizeof(PARTITION_TABLE_ENTRY));
 103
 104                 return TRUE;
 105         }
 106         else
 107         {
 108                 // They want an extended partition entry so we will need
 109                 // to loop through all the extended partitions on the disk
 110                 // and return the one they want.
 111
 112                 ExtendedPartitionNumber = PartitionNumber - 5;
 113
 114                 // Set the initial relative starting sector to 0
 115                 // This is because extended partition starting
 116                 // sectors a numbered relative to their parent
 117                 ExtendedPartitionOffset = 0;
 118
 119                 for (Index=0; Index<=ExtendedPartitionNumber; Index++)
 120                 {
 121                         // Get the extended partition table entry
 122                         if (!DiskGetFirstExtendedPartitionEntry(&MasterBootRecord, &ExtendedPartitionTableEntry))
 123                         {
 124                                 return FALSE;
 125                         }
 126
 127                         // Adjust the relative starting sector of the partition
 128                         ExtendedPartitionTableEntry.SectorCountBeforePartition += ExtendedPartitionOffset;
 129                         if (ExtendedPartitionOffset == 0)
 130                         {
 131                                 // Set the start of the parrent extended partition
 132                                 ExtendedPartitionOffset = ExtendedPartitionTableEntry.SectorCountBeforePartition;
 133                         }
 134                         // Read the partition boot record
 135                         if (!DiskReadBootRecord(DriveNumber, ExtendedPartitionTableEntry.SectorCountBeforePartition, &MasterBootRecord))
 136                         {
 137                                 return FALSE;
 138                         }
 139
 140                         // Get the first real partition table entry
 141                         if (!DiskGetFirstPartitionEntry(&MasterBootRecord, PartitionTableEntry))
 142                         {
 143                                 return FALSE;
 144                         }
 145
 146                         // Now correct the start sector of the partition
 147                         PartitionTableEntry->SectorCountBeforePartition += ExtendedPartitionTableEntry.SectorCountBeforePartition;
 148                 }
 149
 150                 // When we get here we should have the correct entry
 151                 // already stored in PartitionTableEntry
 152                 // so just return TRUE
 153                 return TRUE;
 154         }
 155
 156 }
 157
 158 BOOL DiskGetFirstPartitionEntry(PMASTER_BOOT_RECORD MasterBootRecord, PPARTITION_TABLE_ENTRY PartitionTableEntry)
 159 {
 160         U32             Index;
 161
 162         for (Index=0; Index<4; Index++)
 163         {
 164                 // Check the system indicator
 165                 // If it's not an extended or unused partition
 166                 // then we're done
 167                 if ((MasterBootRecord->PartitionTable[Index].SystemIndicator != PARTITION_ENTRY_UNUSED) &&
 168                         (MasterBootRecord->PartitionTable[Index].SystemIndicator != PARTITION_EXTENDED) &&
 169                         (MasterBootRecord->PartitionTable[Index].SystemIndicator != PARTITION_XINT13_EXTENDED))
 170                 {
 171                         RtlCopyMemory(PartitionTableEntry, &MasterBootRecord->PartitionTable[Index], sizeof(PARTITION_TABLE_ENTRY));
 172                         return TRUE;
 173                 }
 174         }
 175
 176         return FALSE;
 177 }
 178
 179 BOOL DiskGetFirstExtendedPartitionEntry(PMASTER_BOOT_RECORD MasterBootRecord, PPARTITION_TABLE_ENTRY PartitionTableEntry)
 180 {
 181         U32             Index;
 182
 183         for (Index=0; Index<4; Index++)
 184         {
 185                 // Check the system indicator
 186                 // If it an extended partition then we're done
 187                 if ((MasterBootRecord->PartitionTable[Index].SystemIndicator == PARTITION_EXTENDED) ||
 188                         (MasterBootRecord->PartitionTable[Index].SystemIndicator == PARTITION_XINT13_EXTENDED))
 189                 {
 190                         RtlCopyMemory(PartitionTableEntry, &MasterBootRecord->PartitionTable[Index], sizeof(PARTITION_TABLE_ENTRY));
 191                         return TRUE;
 192                 }
 193         }
 194
 195         return FALSE;
 196 }
 197
 198 BOOL DiskReadBootRecord(U32 DriveNumber, U64 LogicalSectorNumber, PMASTER_BOOT_RECORD BootRecord)
 199 {
 200         char            ErrMsg[64];
 201 #ifdef DEBUG
 202         U32             Index;
 203 #endif
 204
 205         // Read master boot record
 206         if (!MachDiskReadLogicalSectors(DriveNumber, LogicalSectorNumber, 1, (PVOID)DISKREADBUFFER))
 207         {
 208                 return FALSE;
 209         }
 210         RtlCopyMemory(BootRecord, (PVOID)DISKREADBUFFER, sizeof(MASTER_BOOT_RECORD));
 211
 212
 213 #ifdef DEBUG
 214
 215         DbgPrint((DPRINT_DISK, "Dumping partition table for drive 0x%x:\n", DriveNumber));
 216         DbgPrint((DPRINT_DISK, "Boot record logical start sector = %d\n", LogicalSectorNumber));
 217         DbgPrint((DPRINT_DISK, "sizeof(MASTER_BOOT_RECORD) = 0x%x.\n", sizeof(MASTER_BOOT_RECORD)));
 218
 219         for (Index=0; Index<4; Index++)
 220         {
 221                 DbgPrint((DPRINT_DISK, "-------------------------------------------\n"));
 222                 DbgPrint((DPRINT_DISK, "Partition %d\n", (Index + 1)));
 223                 DbgPrint((DPRINT_DISK, "BootIndicator: 0x%x\n", BootRecord->PartitionTable[Index].BootIndicator));
 224                 DbgPrint((DPRINT_DISK, "StartHead: 0x%x\n", BootRecord->PartitionTable[Index].StartHead));
 225                 DbgPrint((DPRINT_DISK, "StartSector (Plus 2 cylinder bits): 0x%x\n", BootRecord->PartitionTable[Index].StartSector));
 226                 DbgPrint((DPRINT_DISK, "StartCylinder: 0x%x\n", BootRecord->PartitionTable[Index].StartCylinder));
 227                 DbgPrint((DPRINT_DISK, "SystemIndicator: 0x%x\n", BootRecord->PartitionTable[Index].SystemIndicator));
 228                 DbgPrint((DPRINT_DISK, "EndHead: 0x%x\n", BootRecord->PartitionTable[Index].EndHead));
 229                 DbgPrint((DPRINT_DISK, "EndSector (Plus 2 cylinder bits): 0x%x\n", BootRecord->PartitionTable[Index].EndSector));
 230                 DbgPrint((DPRINT_DISK, "EndCylinder: 0x%x\n", BootRecord->PartitionTable[Index].EndCylinder));
 231                 DbgPrint((DPRINT_DISK, "SectorCountBeforePartition: 0x%x\n", BootRecord->PartitionTable[Index].SectorCountBeforePartition));
 232                 DbgPrint((DPRINT_DISK, "PartitionSectorCount: 0x%x\n", BootRecord->PartitionTable[Index].PartitionSectorCount));
 233         }
 234
 235 #endif // defined DEBUG
 236
 237         // Check the partition table magic value
 238         if (BootRecord->MasterBootRecordMagic != 0xaa55)
 239         {
 240                 sprintf(ErrMsg, "Invalid partition table magic 0x%x found on drive 0x%x",
 241                         BootRecord->MasterBootRecordMagic, DriveNumber);
 242                 DiskError(ErrMsg, 0);
 243                 return FALSE;
 244         }
 245
 246         return TRUE;
 247 }