KernelLand/Modules/Storage/LVM/mbr.c

   1 /*
   2  * Acess2 Logical Volume Manager
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * mbr.c
   6  * - MBR Parsing Code
   7  */
   8 #define DEBUG   0
   9 #include <acess.h>
  10 #include "lvm.h"
  11 #include "mbr.h"
  12
  13 // === PROTOTYPES ===
  14  int    LVM_MBR_CountSubvolumes(tLVM_Vol *Volume, void *FirstSector);
  15 void    LVM_MBR_PopulateSubvolumes(tLVM_Vol *Volume, void *FirstSector);
  16 Uint64  LVM_MBR_int_ReadExt(tLVM_Vol *Volume, Uint64 Addr, Uint64 *Base, Uint64 *Length);
  17
  18 // === GLOBALS ===
  19 tLVM_Format     gLVM_MBRType = {
  20         .Name = "MBR",
  21         .CountSubvolumes = LVM_MBR_CountSubvolumes,
  22         .PopulateSubvolumes = LVM_MBR_PopulateSubvolumes
  23 };
  24
  25 // === CODE ===
  26 /**
  27  * \brief Initialise a volume as
  28  */
  29 int LVM_MBR_CountSubvolumes(tLVM_Vol *Volume, void *FirstSector)
  30 {
  31         tMBR    *MBR = FirstSector;
  32          int    i;
  33         Uint64  extendedLBA;
  34         Uint64  base, len;
  35          int    numPartitions = 0;
  36
  37         ENTER("pVolume pFirstSector", Volume, FirstSector);
  38
  39         // Count Partitions
  40         numPartitions = 0;
  41         extendedLBA = 0;
  42         for( i = 0; i < 4; i ++ )
  43         {
  44                 if( MBR->Parts[i].SystemID == 0 )       continue;
  45
  46                 if( MBR->Parts[i].Boot == 0x0 || MBR->Parts[i].Boot == 0x80 )   // LBA 28
  47                 {
  48                         base = MBR->Parts[i].LBAStart;
  49                 }
  50                 else if( MBR->Parts[i].Boot == 0x1 || MBR->Parts[i].Boot == 0x81 )      // LBA 48
  51                 {
  52                         base = (MBR->Parts[i].StartHi << 16) | MBR->Parts[i].LBAStart;
  53                 }
  54                 else
  55                         continue ;      // Invalid, so don't count
  56
  57                 if( MBR->Parts[i].SystemID == 0xF || MBR->Parts[i].SystemID == 5 )
  58                 {
  59                         LOG("Extended Partition at 0x%llx", base);
  60                         if(extendedLBA != 0) {
  61                                 Log_Warning(
  62                                         "LBA MBR",
  63                                         "Volume %p has multiple extended partitions, ignoring all but first",
  64                                         Volume
  65                                         );
  66                                 continue;
  67                         }
  68                         extendedLBA = base;
  69                 }
  70                 else
  71                 {
  72                         LOG("Primary Partition at 0x%llx", base);
  73                         numPartitions ++;
  74                 }
  75         }
  76         // Detect the GPT protector
  77         if( extendedLBA == 0 && numPartitions == 1 && MBR->Parts[0].SystemID == 0xEE )
  78         {
  79                 // TODO: Hand off to GPT parsing code
  80                 Log_Warning("LBA MBR", "TODO: Hand off to GPT");
  81         }
  82
  83         // Handle extended partions
  84         while(extendedLBA != 0)
  85         {
  86                 extendedLBA = LVM_MBR_int_ReadExt(Volume, extendedLBA, &base, &len);
  87                 if( extendedLBA == (Uint64)-1 )
  88                         break;
  89                 numPartitions ++;
  90         }
  91         LOG("numPartitions = %i", numPartitions);
  92
  93         LEAVE('i', numPartitions);
  94         return numPartitions;
  95 }
  96
  97 void LVM_MBR_PopulateSubvolumes(tLVM_Vol *Volume, void *FirstSector)
  98 {
  99         Uint64  extendedLBA;
 100         Uint64  base, len;
 101          int    i, j;
 102         tMBR    *MBR = FirstSector;
 103
 104         ENTER("pVolume pFirstSector", Volume, FirstSector);
 105
 106         // --- Fill Partition Info ---
 107         extendedLBA = 0;
 108         for( j = 0, i = 0; i < 4; i ++ )
 109         {
 110                 LOG("MBR->Parts[%i].SystemID = 0x%02x", i, MBR->Parts[i].SystemID);
 111                 if( MBR->Parts[i].SystemID == 0 )       continue;
 112                 if( MBR->Parts[i].Boot == 0x0 || MBR->Parts[i].Boot == 0x80 )   // LBA 28
 113                 {
 114                         base = MBR->Parts[i].LBAStart;
 115                         len = MBR->Parts[i].LBALength;
 116                 }
 117                 else if( MBR->Parts[i].Boot == 0x1 || MBR->Parts[i].Boot == 0x81 )      // LBA 48
 118                 {
 119                         base = (MBR->Parts[i].StartHi << 16) | MBR->Parts[i].LBAStart;
 120                         len = (MBR->Parts[i].LengthHi << 16) | MBR->Parts[i].LBALength;
 121                 }
 122                 else
 123                         continue;
 124
 125                 if( MBR->Parts[i].SystemID == 0xF || MBR->Parts[i].SystemID == 5 ) {
 126                         if(extendedLBA == 0)
 127                                 extendedLBA = base;
 128                         continue;
 129                 }
 130                 // Create Partition
 131                 LVM_int_SetSubvolume_Anon( Volume, j, base, len );
 132                 j ++;
 133
 134         }
 135         // Scan extended partitions
 136         while(extendedLBA != 0)
 137         {
 138                 extendedLBA = LVM_MBR_int_ReadExt(Volume, extendedLBA, &base, &len);
 139                 if(extendedLBA == (Uint64)-1)
 140                         break;
 141                 LVM_int_SetSubvolume_Anon( Volume, j, base, len );
 142                 j ++ ;
 143         }
 144
 145         LEAVE('-');
 146 }
 147
 148 /**
 149  * \brief Reads an extended partition
 150  * \return LBA of next Extended, -1 on error, 0 for last
 151  */
 152 Uint64 LVM_MBR_int_ReadExt(tLVM_Vol *Volume, Uint64 Addr, Uint64 *Base, Uint64 *Length)
 153 {
 154         Uint64  link = 0;
 155          int    bFoundPart = 0;;
 156          int    i;
 157         tMBR    mbr;
 158         Uint64  base, len;
 159
 160         // TODO: Handle non-512 byte sectors
 161         if( LVM_int_ReadVolume( Volume, Addr, 1, &mbr ) != 0 )
 162                 return -1;      // Stop on Errors
 163
 164         for( i = 0; i < 4; i ++ )
 165         {
 166                 if( mbr.Parts[i].SystemID == 0 )        continue;
 167
 168                 // LBA 24
 169                 if( mbr.Parts[i].Boot == 0x0 || mbr.Parts[i].Boot == 0x80 ) {
 170                         base = mbr.Parts[i].LBAStart;
 171                         len = mbr.Parts[i].LBALength;
 172                 }
 173                 // LBA 48
 174                 else if( mbr.Parts[i].Boot == 0x1 || mbr.Parts[i].Boot == 0x81 ) {
 175                         base = (mbr.Parts[i].StartHi << 16) | mbr.Parts[i].LBAStart;
 176                         len = (mbr.Parts[i].LengthHi << 16) | mbr.Parts[i].LBALength;
 177                 }
 178                 else {
 179                         Log_Warning("LVM MBR",
 180                                 "Unknown partition type 0x%x, Volume %p Ext 0x%llx Part %i",
 181                                 mbr.Parts[i].Boot, Volume, Addr, i
 182                                 );
 183                         return -1;
 184                 }
 185
 186                 switch(mbr.Parts[i].SystemID)
 187                 {
 188                 case 0xF:
 189                 case 0x5:
 190                         if(link != 0) {
 191                                 Log_Warning("LVM MBR",
 192                                         "Volume %p has two forward links in the extended partition",
 193                                         Volume
 194                                         );
 195                                 return -1;
 196                         }
 197                         link = base;
 198                         break;
 199                 default:
 200                         if(bFoundPart) {
 201                                 Warning("LVM MBR",
 202                                         "Volume %p has more than one partition in the extended partition at 0x%llx",
 203                                         Volume, Addr
 204                                         );
 205                                 return -1;
 206                         }
 207                         bFoundPart = 1;
 208                         *Base = Addr + base;    // Extended partitions are based off the sub-mbr
 209                         *Length = len;
 210                         break;
 211                 }
 212         }
 213
 214         if(!bFoundPart) {
 215                 Log_Warning("LVM MBR",
 216                         "No partition in extended partiton, Volume %p 0x%llx",
 217                         Volume, Addr
 218                         );
 219                 return -1;
 220         }
 221
 222         return link;
 223 }