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[UDF] Parse timestamps from xattr.

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This commit is contained in:
Natalia Portillo
2026-02-01 10:15:48 +00:00
parent 5e5df3e086
commit 22b698f002
2 changed files with 118 additions and 0 deletions
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102
Aaru.Filesystems/UDF/File.cs
View File

@@ -175,6 +175,17 @@ public sealed partial class UDF
stat.LastWriteTimeUtc = EcmaToDateTime(macVolumeInfo.Value.lastModificationDate);
stat.BackupTimeUtc = EcmaToDateTime(macVolumeInfo.Value.lastBackupDate);
}
// Check for ch.ecma.file_times extended attribute
GetFileTimesFromEa(feBuffer,
fileEntryInfo,
out DateTime? eaAccessTime,
out DateTime? eaModificationTime,
out DateTime? eaAttributeTime);
if(eaAccessTime.HasValue) stat.AccessTimeUtc = eaAccessTime.Value;
if(eaModificationTime.HasValue) stat.LastWriteTimeUtc = eaModificationTime.Value;
if(eaAttributeTime.HasValue) stat.StatusChangeTimeUtc = eaAttributeTime.Value;
}
// Check for *UDF Backup named stream (UDF 2.00+)
@@ -620,4 +631,95 @@ public sealed partial class UDF
return path.Length > 0 ? path.ToString() : null;
}
/// <summary>
/// Gets file times from the ch.ecma.file_times extended attribute if present
/// </summary>
static DateTime? GetFileTimesFromEa(byte[] feBuffer, UdfFileEntryInfo fileEntryInfo, out DateTime? accessTime,
out DateTime? modificationTime, out DateTime? attributeTime)
{
accessTime = null;
modificationTime = null;
attributeTime = null;
if(fileEntryInfo.LengthOfExtendedAttributes == 0) return null;
int fixedSize = fileEntryInfo.IsExtended ? 216 : 176;
int eaOffset = fixedSize;
int eaEnd = fixedSize + (int)fileEntryInfo.LengthOfExtendedAttributes;
// First, check for Extended Attribute Header Descriptor
if(eaEnd - eaOffset >= 24)
{
var tagId = (TagIdentifier)BitConverter.ToUInt16(feBuffer, eaOffset);
if(tagId == TagIdentifier.ExtendedAttributeHeaderDescriptor) eaOffset += 24;
}
while(eaOffset + 12 <= eaEnd)
{
GenericExtendedAttributeHeader eaHeader =
Marshal.ByteArrayToStructureLittleEndian<GenericExtendedAttributeHeader>(feBuffer, eaOffset, 12);
if(eaHeader.attributeLength == 0) break;
// Look for file times EA (type 5)
if(eaHeader.attributeType == 5) // EA_TYPE_FILE_TIMES
{
// File Times EA format:
// Offset 0-3: Attribute Type (4 bytes)
// Offset 4: Attribute Subtype (1 byte)
// Offset 5-7: Reserved (3 bytes)
// Offset 8-11: Attribute Length (4 bytes)
// Offset 12-15: Data Length (4 bytes)
// Offset 16-19: File Time Existence (4 bytes) - bitmask indicating which times are present
// Offset 20+: File Times data (variable length)
if(eaOffset + 20 > feBuffer.Length) break;
var timeExistenceMask = BitConverter.ToUInt32(feBuffer, eaOffset + 16);
int timesOffset = eaOffset + 20;
// Bit 0: Access time present
// Bit 1: Modification time present
// Bit 2: Attribute time present
if((timeExistenceMask & 0x01) != 0 && timesOffset + 12 <= feBuffer.Length)
{
Timestamp ts = Marshal.ByteArrayToStructureLittleEndian<Timestamp>(feBuffer, timesOffset, 12);
accessTime = EcmaToDateTime(ts);
timesOffset += 12;
}
if((timeExistenceMask & 0x02) != 0 && timesOffset + 12 <= feBuffer.Length)
{
Timestamp ts = Marshal.ByteArrayToStructureLittleEndian<Timestamp>(feBuffer, timesOffset, 12);
modificationTime = EcmaToDateTime(ts);
timesOffset += 12;
}
if((timeExistenceMask & 0x04) != 0 && timesOffset + 12 <= feBuffer.Length)
{
Timestamp ts = Marshal.ByteArrayToStructureLittleEndian<Timestamp>(feBuffer, timesOffset, 12);
attributeTime = EcmaToDateTime(ts);
}
return accessTime ?? modificationTime ?? attributeTime;
}
eaOffset += (int)eaHeader.attributeLength;
}
return null;
}
/// <summary>
/// Checks if a specific extended attribute type should be hidden from ListXAttr
/// because it's handled specially in other methods (like Stat)
/// </summary>
static bool IsEaHandledSpecially(uint attributeType) =>
// File times EA (type 5) is handled in Stat method
// Info times EA (type 6) could also be handled similarly if needed
attributeType == 5; // EA_TYPE_FILE_TIMES
}

16
Aaru.Filesystems/UDF/Xattr.cs
View File

@@ -156,6 +156,14 @@ public sealed partial class UDF
if(eaHeader.attributeLength == 0) break;
// Skip EAs that are handled specially (e.g., file times are parsed in Stat)
if(IsEaHandledSpecially(eaHeader.attributeType))
{
eaOffset += (int)eaHeader.attributeLength;
continue;
}
// Special handling for OS/2 EAs - they contain multiple FEA entries
if(eaHeader.attributeType == EA_TYPE_IMPLEMENTATION)
{
@@ -261,6 +269,14 @@ public sealed partial class UDF
if(eaHeader.attributeLength == 0) break;
// Skip EAs that are handled specially (e.g., file times are parsed in Stat)
if(IsEaHandledSpecially(eaHeader.attributeType))
{
eaOffset += (int)eaHeader.attributeLength;
continue;
}
// Special handling for OS/2 EAs
if(eaHeader.attributeType == EA_TYPE_IMPLEMENTATION &&
xattr.StartsWith("com.ibm.os2.", StringComparison.Ordinal))