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