boot/freeldr/freeldr/arch/i386/drivemap.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 along
  16  *  with this program; if not, write to the Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <freeldr.h>
  21 #include <debug.h>
  22
  23 DBG_DEFAULT_CHANNEL(WARNING);
  24
  25 BOOLEAN      DriveMapInstalled = FALSE;    // Tells us if we have already installed our drive map int 13h handler code
  26 ULONG        OldInt13HandlerAddress = 0;   // Address of BIOS int 13h handler
  27 ULONG        DriveMapHandlerAddress = 0;   // Linear address of our drive map handler
  28 ULONG        DriveMapHandlerSegOff = 0;    // Segment:offset style address of our drive map handler
  29
  30 #ifndef _MSC_VER
  31 VOID DriveMapMapDrivesInSection(PCSTR SectionName)
  32 {
  33     CHAR            SettingName[80];
  34     CHAR            SettingValue[80];
  35     CHAR            ErrorText[260];
  36     CHAR            Drive1[80];
  37     CHAR            Drive2[80];
  38     ULONG                SectionId;
  39     ULONG                SectionItemCount;
  40     ULONG                Index;
  41     ULONG                Index2;
  42     DRIVE_MAP_LIST    DriveMapList;
  43
  44     RtlZeroMemory(&DriveMapList, sizeof(DRIVE_MAP_LIST));
  45
  46     if (!IniOpenSection(SectionName, &SectionId))
  47     {
  48         return;
  49     }
  50
  51     // Get the number of items in this section
  52     SectionItemCount = IniGetNumSectionItems(SectionId);
  53
  54     // Loop through each one and check if its a DriveMap= setting
  55     for (Index=0; Index<SectionItemCount; Index++)
  56     {
  57         // Get the next setting from the .ini file section
  58         if (IniReadSettingByNumber(SectionId, Index, SettingName, sizeof(SettingName), SettingValue, sizeof(SettingValue)))
  59         {
  60             if (_stricmp(SettingName, "DriveMap") == 0)
  61             {
  62                 // Make sure we haven't exceeded the drive map max count
  63                 if (DriveMapList.DriveMapCount >= 4)
  64                 {
  65                     sprintf(ErrorText, "Max DriveMap count exceeded in section [%s]:\n\n%s=%s", SectionName, SettingName, SettingValue);
  66                     UiMessageBox(ErrorText);
  67                     continue;
  68                 }
  69
  70                 RtlZeroMemory(Drive1, 80);
  71                 RtlZeroMemory(Drive2, 80);
  72
  73                 strcpy(Drive1, SettingValue);
  74
  75                 // Parse the setting value and separate a string "hd0,hd1"
  76                 // into two strings "hd0" and "hd1"
  77                 for (Index2=0; Index2<strlen(Drive1); Index2++)
  78                 {
  79                     // Check if this character is the separater character (comma - ',')
  80                     if (Drive1[Index2] == ',')
  81                     {
  82                         Drive1[Index2] = '\0';
  83                         strcpy(Drive2, &Drive1[Index2+1]);
  84                         break;
  85                     }
  86                 }
  87
  88                 // Make sure we got good values before we add them to the map
  89                 if (!DriveMapIsValidDriveString(Drive1) || !DriveMapIsValidDriveString(Drive2))
  90                 {
  91                     sprintf(ErrorText, "Error in DriveMap setting in section [%s]:\n\n%s=%s", SectionName, SettingName, SettingValue);
  92                     UiMessageBox(ErrorText);
  93                     continue;
  94                 }
  95
  96                 // Add them to the map
  97                 DriveMapList.DriveMap[(DriveMapList.DriveMapCount * 2)] = DriveMapGetBiosDriveNumber(Drive1);
  98                 DriveMapList.DriveMap[(DriveMapList.DriveMapCount * 2)+1] = DriveMapGetBiosDriveNumber(Drive2);
  99                 DriveMapList.DriveMapCount++;
 100
 101                 TRACE("Mapping BIOS drive 0x%x to drive 0x%x\n", DriveMapGetBiosDriveNumber(Drive1), DriveMapGetBiosDriveNumber(Drive2));
 102             }
 103         }
 104     }
 105
 106     if (DriveMapList.DriveMapCount)
 107     {
 108         TRACE("Installing Int13 drive map for %d drives.\n", DriveMapList.DriveMapCount);
 109         DriveMapInstallInt13Handler(&DriveMapList);
 110     }
 111     else
 112     {
 113         TRACE("Removing any previously installed Int13 drive map.\n");
 114         DriveMapRemoveInt13Handler();
 115     }
 116 }
 117
 118 BOOLEAN DriveMapIsValidDriveString(PCSTR DriveString)
 119 {
 120     ULONG        Index;
 121
 122     // Now verify that the user has given us appropriate strings
 123     if ((strlen(DriveString) < 3) ||
 124         ((DriveString[0] != 'f') && (DriveString[0] != 'F') && (DriveString[0] != 'h') && (DriveString[0] != 'H')) ||
 125         ((DriveString[1] != 'd') && (DriveString[1] != 'D')))
 126     {
 127         return FALSE;
 128     }
 129
 130     // Now verify that the user has given us appropriate numbers
 131     // Make sure that only numeric characters were given
 132     for (Index=2; Index<strlen(DriveString); Index++)
 133     {
 134         if (DriveString[Index] < '0' || DriveString[Index] > '9')
 135         {
 136             return FALSE;
 137         }
 138     }
 139     // Now make sure that they are not outrageous values (i.e. hd90874)
 140     if ((atoi(&DriveString[2]) < 0) || (atoi(&DriveString[2]) > 0xff))
 141     {
 142         return FALSE;
 143     }
 144
 145     return TRUE;
 146 }
 147 #endif
 148
 149 UCHAR DriveMapGetBiosDriveNumber(PCSTR DeviceName)
 150 {
 151     UCHAR        BiosDriveNumber = 0;
 152
 153     // If they passed in a number string then just
 154     // convert it to decimal and return it
 155     if (DeviceName[0] >= '0' && DeviceName[0] <= '9')
 156     {
 157         return atoi(DeviceName);
 158     }
 159
 160     // Convert the drive number string into a number
 161     // 'hd1' = 1
 162     BiosDriveNumber = atoi(&DeviceName[2]);
 163
 164     // If it's a hard disk then set the high bit
 165     if ((DeviceName[0] == 'h' || DeviceName[0] == 'H') &&
 166         (DeviceName[1] == 'd' || DeviceName[1] == 'D'))
 167     {
 168         BiosDriveNumber |= 0x80;
 169     }
 170
 171     return BiosDriveNumber;
 172 }
 173
 174 #ifndef _MSC_VER
 175 VOID DriveMapInstallInt13Handler(PDRIVE_MAP_LIST DriveMap)
 176 {
 177     ULONG*    RealModeIVT = (ULONG*)0x00000000;
 178     USHORT*    BiosLowMemorySize = (USHORT*)0x00000413;
 179
 180     if (!DriveMapInstalled)
 181     {
 182         // Get the old INT 13h handler address from the vector table
 183         OldInt13HandlerAddress = RealModeIVT[0x13];
 184
 185         // Decrease the size of low memory
 186         (*BiosLowMemorySize)--;
 187
 188         // Get linear address for drive map handler
 189         DriveMapHandlerAddress = (ULONG)(*BiosLowMemorySize) << 10;
 190
 191         // Convert to segment:offset style address
 192         DriveMapHandlerSegOff = (DriveMapHandlerAddress << 12) & 0xffff0000;
 193     }
 194
 195     // Copy the drive map structure to the proper place
 196     RtlCopyMemory(&DriveMapInt13HandlerMapList, DriveMap, sizeof(DRIVE_MAP_LIST));
 197
 198     // Set the address of the BIOS INT 13h handler
 199     DriveMapOldInt13HandlerAddress = OldInt13HandlerAddress;
 200
 201     // Copy the code to our reserved area
 202     RtlCopyMemory((PVOID)DriveMapHandlerAddress, &DriveMapInt13HandlerStart, ((ULONG)&DriveMapInt13HandlerEnd - (ULONG)&DriveMapInt13HandlerStart));
 203
 204     // Update the IVT
 205     RealModeIVT[0x13] = DriveMapHandlerSegOff;
 206
 207     CacheInvalidateCacheData();
 208     DriveMapInstalled = TRUE;
 209 }
 210
 211 VOID DriveMapRemoveInt13Handler(VOID)
 212 {
 213     ULONG*    RealModeIVT = (ULONG*)0x00000000;
 214     USHORT*    BiosLowMemorySize = (USHORT*)0x00000413;
 215
 216     if (DriveMapInstalled)
 217     {
 218         // Get the old INT 13h handler address from the vector table
 219         RealModeIVT[0x13] = OldInt13HandlerAddress;
 220
 221         // Increase the size of low memory
 222         (*BiosLowMemorySize)++;
 223
 224         CacheInvalidateCacheData();
 225         DriveMapInstalled = FALSE;
 226     }
 227 }
 228 #endif