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         while(extendedLBA != 0)
  77         {
  78                 extendedLBA = LVM_MBR_int_ReadExt(Volume, extendedLBA, &base, &len);
  79                 if( extendedLBA == (Uint64)-1 )
  80                         break;
  81                 numPartitions ++;
  82         }
  83         LOG("numPartitions = %i", numPartitions);
  84
  85         LEAVE('i', numPartitions);
  86         return numPartitions;
  87 }
  88
  89 void LVM_MBR_PopulateSubvolumes(tLVM_Vol *Volume, void *FirstSector)
  90 {
  91         Uint64  extendedLBA;
  92         Uint64  base, len;
  93          int    i, j;
  94         tMBR    *MBR = FirstSector;
  95
  96         ENTER("pVolume pFirstSector", Volume, FirstSector);
  97
  98         // --- Fill Partition Info ---
  99         extendedLBA = 0;
 100         for( j = 0, i = 0; i < 4; i ++ )
 101         {
 102                 LOG("MBR->Parts[%i].SystemID = 0x%02x", i, MBR->Parts[i].SystemID);
 103                 if( MBR->Parts[i].SystemID == 0 )       continue;
 104                 if( MBR->Parts[i].Boot == 0x0 || MBR->Parts[i].Boot == 0x80 )   // LBA 28
 105                 {
 106                         base = MBR->Parts[i].LBAStart;
 107                         len = MBR->Parts[i].LBALength;
 108                 }
 109                 else if( MBR->Parts[i].Boot == 0x1 || MBR->Parts[i].Boot == 0x81 )      // LBA 48
 110                 {
 111                         base = (MBR->Parts[i].StartHi << 16) | MBR->Parts[i].LBAStart;
 112                         len = (MBR->Parts[i].LengthHi << 16) | MBR->Parts[i].LBALength;
 113                 }
 114                 else
 115                         continue;
 116
 117                 if( MBR->Parts[i].SystemID == 0xF || MBR->Parts[i].SystemID == 5 ) {
 118                         if(extendedLBA == 0)
 119                                 extendedLBA = base;
 120                         continue;
 121                 }
 122                 // Create Partition
 123                 LVM_int_SetSubvolume_Anon( Volume, j, base, len );
 124                 j ++;
 125
 126         }
 127         // Scan extended partitions
 128         while(extendedLBA != 0)
 129         {
 130                 extendedLBA = LVM_MBR_int_ReadExt(Volume, extendedLBA, &base, &len);
 131                 if(extendedLBA == (Uint64)-1)
 132                         break;
 133                 LVM_int_SetSubvolume_Anon( Volume, j, base, len );
 134                 j ++ ;
 135         }
 136
 137         LEAVE('-');
 138 }
 139
 140 /**
 141  * \brief Reads an extended partition
 142  * \return LBA of next Extended, -1 on error, 0 for last
 143  */
 144 Uint64 LVM_MBR_int_ReadExt(tLVM_Vol *Volume, Uint64 Addr, Uint64 *Base, Uint64 *Length)
 145 {
 146         Uint64  link = 0;
 147          int    bFoundPart = 0;;
 148          int    i;
 149         tMBR    mbr;
 150         Uint64  base, len;
 151
 152         // TODO: Handle non-512 byte sectors
 153         if( LVM_int_ReadVolume( Volume, Addr, 1, &mbr ) != 0 )
 154                 return -1;      // Stop on Errors
 155
 156         for( i = 0; i < 4; i ++ )
 157         {
 158                 if( mbr.Parts[i].SystemID == 0 )        continue;
 159
 160                 // LBA 24
 161                 if( mbr.Parts[i].Boot == 0x0 || mbr.Parts[i].Boot == 0x80 ) {
 162                         base = mbr.Parts[i].LBAStart;
 163                         len = mbr.Parts[i].LBALength;
 164                 }
 165                 // LBA 48
 166                 else if( mbr.Parts[i].Boot == 0x1 || mbr.Parts[i].Boot == 0x81 ) {
 167                         base = (mbr.Parts[i].StartHi << 16) | mbr.Parts[i].LBAStart;
 168                         len = (mbr.Parts[i].LengthHi << 16) | mbr.Parts[i].LBALength;
 169                 }
 170                 else {
 171                         Log_Warning("LVM MBR",
 172                                 "Unknown partition type 0x%x, Volume %p Ext 0x%llx Part %i",
 173                                 mbr.Parts[i].Boot, Volume, Addr, i
 174                                 );
 175                         return -1;
 176                 }
 177
 178                 switch(mbr.Parts[i].SystemID)
 179                 {
 180                 case 0xF:
 181                 case 0x5:
 182                         if(link != 0) {
 183                                 Log_Warning("LVM MBR",
 184                                         "Volume %p has two forward links in the extended partition",
 185                                         Volume
 186                                         );
 187                                 return -1;
 188                         }
 189                         link = base;
 190                         break;
 191                 default:
 192                         if(bFoundPart) {
 193                                 Warning("LVM MBR",
 194                                         "Volume %p has more than one partition in the extended partition at 0x%llx",
 195                                         Volume, Addr
 196                                         );
 197                                 return -1;
 198                         }
 199                         bFoundPart = 1;
 200                         *Base = Addr + base;    // Extended partitions are based off the sub-mbr
 201                         *Length = len;
 202                         break;
 203                 }
 204         }
 205
 206         if(!bFoundPart) {
 207                 Log_Warning("LVM MBR",
 208                         "No partition in extended partiton, Volume %p 0x%llx",
 209                         Volume, Addr
 210                         );
 211                 return -1;
 212         }
 213
 214         return link;
 215 }