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_Detect(tLVM_Vol *Volume);
  15  int    LVM_MBR_CountSubvolumes(tLVM_Vol *Volume, void *FirstSector);
  16 void    LVM_MBR_PopulateSubvolumes(tLVM_Vol *Volume, void *FirstSector);
  17 Uint64  LVM_MBR_int_ReadExt(tLVM_Vol *Volume, Uint64 Addr, Uint64 *Base, Uint64 *Length);
  18
  19 // === GLOBALS ===
  20 tLVM_Format     gLVM_MBRType = {
  21         .Name = "MBR",
  22         .CountSubvolumes = LVM_MBR_CountSubvolumes,
  23         .PopulateSubvolumes = LVM_MBR_PopulateSubvolumes
  24 };
  25
  26 // === CODE ===
  27 int LVM_MBR_Detect(tLVM_Vol *Volume)
  28 {
  29         tMBR    mbr;
  30         // TODO: handle non-512 byte sectors
  31         if( LVM_int_ReadVolume( Volume, 0, 1, &mbr ) != 0 )
  32                 return -1;      // Stop on Errors
  33
  34         if( mbr.BootFlag != LittleEndian16(0xAA55) )
  35                 return 0;
  36
  37         return 1;
  38 }
  39
  40 /**
  41  * \brief Initialise a volume as
  42  */
  43 int LVM_MBR_CountSubvolumes(tLVM_Vol *Volume, void *FirstSector)
  44 {
  45         tMBR    *MBR = FirstSector;
  46         Uint64  extendedLBA;
  47         Uint64  base, len;
  48          int    numPartitions = 0;
  49
  50         ENTER("pVolume pFirstSector", Volume, FirstSector);
  51
  52         // Count Partitions
  53         numPartitions = 0;
  54         extendedLBA = 0;
  55         for( int i = 0; i < 4; i ++ )
  56         {
  57                 if( MBR->Parts[i].SystemID == 0 )       continue;
  58
  59                 if( MBR->Parts[i].Boot == 0x0 || MBR->Parts[i].Boot == 0x80 )   // LBA 28
  60                 {
  61                         base = MBR->Parts[i].LBAStart;
  62                 }
  63                 else if( MBR->Parts[i].Boot == 0x1 || MBR->Parts[i].Boot == 0x81 )      // LBA 48
  64                 {
  65                         base = (MBR->Parts[i].StartHi << 16) | MBR->Parts[i].LBAStart;
  66                 }
  67                 else
  68                         continue ;      // Invalid, so don't count
  69
  70                 if( MBR->Parts[i].SystemID == 0xF || MBR->Parts[i].SystemID == 5 )
  71                 {
  72                         LOG("Extended Partition at 0x%llx", base);
  73                         if(extendedLBA != 0) {
  74                                 Log_Warning(
  75                                         "LBA MBR",
  76                                         "Volume %p has multiple extended partitions, ignoring all but first",
  77                                         Volume
  78                                         );
  79                                 continue;
  80                         }
  81                         extendedLBA = base;
  82                 }
  83                 else
  84                 {
  85                         LOG("Primary Partition at 0x%llx", base);
  86                         numPartitions ++;
  87                 }
  88         }
  89         // Detect the GPT protector
  90         if( extendedLBA == 0 && numPartitions == 1 && MBR->Parts[0].SystemID == 0xEE )
  91         {
  92                 // TODO: Hand off to GPT parsing code
  93                 Log_Warning("LBA MBR", "TODO: Hand off to GPT");
  94         }
  95
  96         // Handle extended partions
  97         while(extendedLBA != 0)
  98         {
  99                 extendedLBA = LVM_MBR_int_ReadExt(Volume, extendedLBA, &base, &len);
 100                 if( extendedLBA == (Uint64)-1 )
 101                         break;
 102                 numPartitions ++;
 103         }
 104         LOG("numPartitions = %i", numPartitions);
 105
 106         LEAVE('i', numPartitions);
 107         return numPartitions;
 108 }
 109
 110 void LVM_MBR_PopulateSubvolumes(tLVM_Vol *Volume, void *FirstSector)
 111 {
 112         Uint64  extendedLBA;
 113         Uint64  base, len;
 114          int    i, j;
 115         tMBR    *MBR = FirstSector;
 116
 117         ENTER("pVolume pFirstSector", Volume, FirstSector);
 118
 119         // --- Fill Partition Info ---
 120         extendedLBA = 0;
 121         for( j = 0, i = 0; i < 4; i ++ )
 122         {
 123                 LOG("MBR->Parts[%i].SystemID = 0x%02x", i, MBR->Parts[i].SystemID);
 124                 if( MBR->Parts[i].SystemID == 0 )       continue;
 125                 if( MBR->Parts[i].Boot == 0x0 || MBR->Parts[i].Boot == 0x80 )   // LBA 28
 126                 {
 127                         base = MBR->Parts[i].LBAStart;
 128                         len = MBR->Parts[i].LBALength;
 129                 }
 130                 else if( MBR->Parts[i].Boot == 0x1 || MBR->Parts[i].Boot == 0x81 )      // LBA 48
 131                 {
 132                         base = (MBR->Parts[i].StartHi << 16) | MBR->Parts[i].LBAStart;
 133                         len = (MBR->Parts[i].LengthHi << 16) | MBR->Parts[i].LBALength;
 134                 }
 135                 else
 136                         continue;
 137
 138                 if( MBR->Parts[i].SystemID == 0xF || MBR->Parts[i].SystemID == 5 ) {
 139                         if(extendedLBA == 0)
 140                                 extendedLBA = base;
 141                         continue;
 142                 }
 143                 // Create Partition
 144                 LVM_int_SetSubvolume_Anon( Volume, j, base, len );
 145                 j ++;
 146
 147         }
 148         // Scan extended partitions
 149         while(extendedLBA != 0)
 150         {
 151                 extendedLBA = LVM_MBR_int_ReadExt(Volume, extendedLBA, &base, &len);
 152                 if(extendedLBA == (Uint64)-1)
 153                         break;
 154                 LVM_int_SetSubvolume_Anon( Volume, j, base, len );
 155                 j ++ ;
 156         }
 157
 158         LEAVE('-');
 159 }
 160
 161 /**
 162  * \brief Reads an extended partition
 163  * \return LBA of next Extended, -1 on error, 0 for last
 164  */
 165 Uint64 LVM_MBR_int_ReadExt(tLVM_Vol *Volume, Uint64 Addr, Uint64 *Base, Uint64 *Length)
 166 {
 167         Uint64  link = 0;
 168          int    bFoundPart = 0;;
 169          int    i;
 170         tMBR    mbr;
 171         Uint64  base, len;
 172
 173         // TODO: Handle non-512 byte sectors
 174         if( LVM_int_ReadVolume( Volume, Addr, 1, &mbr ) != 0 )
 175                 return -1;      // Stop on Errors
 176
 177         for( i = 0; i < 4; i ++ )
 178         {
 179                 if( mbr.Parts[i].SystemID == 0 )        continue;
 180
 181                 // LBA 24
 182                 if( mbr.Parts[i].Boot == 0x0 || mbr.Parts[i].Boot == 0x80 ) {
 183                         base = mbr.Parts[i].LBAStart;
 184                         len = mbr.Parts[i].LBALength;
 185                 }
 186                 // LBA 48
 187                 else if( mbr.Parts[i].Boot == 0x1 || mbr.Parts[i].Boot == 0x81 ) {
 188                         base = (mbr.Parts[i].StartHi << 16) | mbr.Parts[i].LBAStart;
 189                         len = (mbr.Parts[i].LengthHi << 16) | mbr.Parts[i].LBALength;
 190                 }
 191                 else {
 192                         Log_Warning("LVM MBR",
 193                                 "Unknown partition type 0x%x, Volume %p Ext 0x%llx Part %i",
 194                                 mbr.Parts[i].Boot, Volume, Addr, i
 195                                 );
 196                         return -1;
 197                 }
 198
 199                 switch(mbr.Parts[i].SystemID)
 200                 {
 201                 case 0xF:
 202                 case 0x5:
 203                         if(link != 0) {
 204                                 Log_Warning("LVM MBR",
 205                                         "Volume %p has two forward links in the extended partition",
 206                                         Volume
 207                                         );
 208                                 return -1;
 209                         }
 210                         link = base;
 211                         break;
 212                 default:
 213                         if(bFoundPart) {
 214                                 Warning("LVM MBR",
 215                                         "Volume %p has more than one partition in the extended partition at 0x%llx",
 216                                         Volume, Addr
 217                                         );
 218                                 return -1;
 219                         }
 220                         bFoundPart = 1;
 221                         *Base = Addr + base;    // Extended partitions are based off the sub-mbr
 222                         *Length = len;
 223                         break;
 224                 }
 225         }
 226
 227         if(!bFoundPart) {
 228                 Log_Warning("LVM MBR",
 229                         "No partition in extended partiton, Volume %p 0x%llx",
 230                         Volume, Addr
 231                         );
 232                 return -1;
 233         }
 234
 235         return link;
 236 }