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Detect CD-i Ready when the drive returns data scrambled.

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This commit is contained in:
Natalia Portillo
2020-06-23 00:26:55 +01:00
parent aca0c78bad
commit 651a2df2aa
1 changed files with 110 additions and 4 deletions
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114
Aaru.Core/Media/Detection/MMC.cs
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@@ -149,6 +149,65 @@ namespace Aaru.Core.Media.Detection
return syncMark.SequenceEqual(testMark) && (sector[0xF] == 0 || sector[0xF] == 1 || sector[0xF] == 2);
}
static bool IsScrambledData(byte[] sector, int wantedLba, out int offset)
{
offset = 0;
if(sector?.Length != 2352)
return false;
byte[] syncMark =
{
0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00
};
byte[] testMark = new byte[12];
for(int i = 0; i <= 2336; i++)
{
Array.Copy(sector, i, testMark, 0, 12);
if(syncMark.SequenceEqual(testMark) &&
(sector[i + 0xF] == 0x60 || sector[i + 0xF] == 0x61 || sector[i + 0xF] == 0x62))
{
// De-scramble M and S
int minute = sector[i + 12] ^ 0x01;
int second = sector[i + 13] ^ 0x80;
int frame = sector[i + 14];
// Convert to binary
minute = ((minute / 16) * 10) + (minute & 0x0F);
second = ((second / 16) * 10) + (second & 0x0F);
frame = ((frame / 16) * 10) + (frame & 0x0F);
// Calculate the first found LBA
int lba = ((minute * 60 * 75) + (second * 75) + frame) - 150;
// Calculate the difference between the found LBA and the requested one
int diff = wantedLba - lba;
offset = i + (2352 * diff);
return true;
}
}
return false;
}
// TODO: Negative offset
static byte[] DescrambleAndFixOffset(byte[] sector, int offsetBytes, int sectorsForOffset)
{
byte[] descrambled = new byte[2352];
int offsetFix = offsetBytes < 0 ? (2352 * sectorsForOffset) + offsetBytes : offsetBytes;
Array.Copy(sector, offsetFix, descrambled, 0, 2352);
return Sector.Scramble(descrambled);
}
/// <summary>Checks if the media corresponds to CD-i.</summary>
/// <param name="sector0">Contents of LBA 0, with all headers.</param>
/// <param name="sector16">Contents of LBA 0, with all headers.</param>
@@ -242,8 +301,8 @@ namespace Aaru.Core.Media.Detection
if(decodedToc.HasValue)
if(decodedToc.Value.TrackDescriptors.Any(t => t.SessionNumber == 2))
secondSessionFirstTrack =
decodedToc.Value.TrackDescriptors.Where(t => t.SessionNumber == 2).Min(t => t.POINT);
secondSessionFirstTrack = decodedToc.Value.TrackDescriptors.Where(t => t.SessionNumber == 2).
Min(t => t.POINT);
if(mediaType == MediaType.CD ||
mediaType == MediaType.CDROMXA)
@@ -377,7 +436,7 @@ namespace Aaru.Core.Media.Detection
uint firstSectorSecondSessionFirstTrack =
(uint)(((secondSessionFirstTrackTrack.PHOUR * 3600 * 75) +
(secondSessionFirstTrackTrack.PMIN * 60 * 75) + (secondSessionFirstTrackTrack.PSEC * 75) +
(secondSessionFirstTrackTrack.PMIN * 60 * 75) + (secondSessionFirstTrackTrack.PSEC * 75) +
secondSessionFirstTrackTrack.PFRAME) - 150);
sense = dev.ReadCd(out cmdBuf, out _, firstSectorSecondSessionFirstTrack, 2352, 1,
@@ -454,7 +513,7 @@ namespace Aaru.Core.Media.Detection
if(firstTrack.POINT == 1)
{
uint firstTrackSector = (uint)(((firstTrack.PHOUR * 3600 * 75) + (firstTrack.PMIN * 60 * 75) +
(firstTrack.PSEC * 75) + firstTrack.PFRAME) - 150);
(firstTrack.PSEC * 75) + firstTrack.PFRAME) - 150);
// Check for hidden data before start of track 1
if(firstTrackSector > 0)
@@ -479,6 +538,53 @@ namespace Aaru.Core.Media.Detection
if(IsCdi(sector0, sector16))
{
mediaType = MediaType.CDIREADY;
return;
}
}
else
{
hiddenData = IsScrambledData(sector0, 0, out int combinedOffset);
if(hiddenData)
{
int sectorsForOffset = combinedOffset / 2352;
if(sectorsForOffset < 0)
sectorsForOffset *= -1;
if(combinedOffset % 2352 != 0)
sectorsForOffset++;
int lba0 = 0;
int lba16 = 16;
if(combinedOffset < 0)
{
lba0 -= sectorsForOffset - 1;
lba16 -= sectorsForOffset - 1;
}
sense = dev.ReadCd(out sector0, out _, (uint)lba0, 2352, (uint)sectorsForOffset + 1,
MmcSectorTypes.AllTypes, false, false, true,
MmcHeaderCodes.AllHeaders, true, true, MmcErrorField.None,
MmcSubchannel.None, dev.Timeout, out _);
sector0 = DescrambleAndFixOffset(sector0, combinedOffset, sectorsForOffset);
sense = dev.ReadCd(out byte[] sector16, out _, (uint)lba16, 2352,
(uint)sectorsForOffset + 1, MmcSectorTypes.AllTypes, false,
false, true, MmcHeaderCodes.AllHeaders, true, true,
MmcErrorField.None, MmcSubchannel.None, dev.Timeout, out _);
sector16 = DescrambleAndFixOffset(sector16, combinedOffset, sectorsForOffset);
if(IsCdi(sector0, sector16))
{
mediaType = MediaType.CDIREADY;
return;
}
}
}
}