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Extract file metadata for DiscUtils-based disc image formats #200

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8f75a09
Initial plan
Copilot Feb 13, 2026
558034a
Initial plan for disc image metadata extraction
Copilot Feb 13, 2026
f71dea8
Add file metadata extraction for DiscUtils-based disc image formats
Copilot Feb 13, 2026
649794a
Plan: Add Windows filesystem metadata support for disc image formats
Copilot Feb 14, 2026
4cd536e
Add Windows filesystem metadata (NTFS/FAT/WIM) to disc image extraction
Copilot Feb 14, 2026
7913f8d
Address review feedback: improve test comment clarity
Copilot Feb 14, 2026
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2 changes: 2 additions & 0 deletions RecursiveExtractor.Tests/ExtractorTests/ExpectedNumFilesTests.cs
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Expand Up @@ -38,6 +38,7 @@ public static TheoryData<string, int> ArchiveData
{ "TestData.a",3 },
{ "TestData.bsd.ar",3 },
{ "TestData.iso",3 },
{ "TestDataRockRidge.iso",2 },
{ "TestData.vhdx",3 },
{ "EmptyFile.txt", 1 },
{ "TestDataArchivesNested.zip", RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? 54 : 52 },
Expand Down Expand Up @@ -79,6 +80,7 @@ public static TheoryData<string, int> NoRecursionData
{ "TestData.a", 3 },
{ "TestData.bsd.ar", 3 },
{ "TestData.iso", 3 },
{ "TestDataRockRidge.iso", 2 },
{ "TestData.vhdx", 3 },
{ "EmptyFile.txt", 1 },
{ "TestDataArchivesNested.zip", 14 },
Expand Down
108 changes: 108 additions & 0 deletions RecursiveExtractor.Tests/ExtractorTests/FileMetadataTests.cs
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Expand Up @@ -101,6 +101,8 @@ public void MetadataDefaults_AreNull()
Assert.Null(metadata.IsExecutable);
Assert.Null(metadata.IsSetUid);
Assert.Null(metadata.IsSetGid);
Assert.Null(metadata.FileAttributes);
Assert.Null(metadata.SecurityDescriptorSddl);
}

[Fact]
Expand Down Expand Up @@ -140,4 +142,110 @@ public void FileEntry_MetadataDefaultsToNull()
var entry = new FileEntry("test.txt", stream);
Assert.Null(entry.Metadata);
}

[Fact]
public async Task IsoEntries_MetadataIsNullWithoutRockRidge()
{
// TestData.iso does not have RockRidge extensions, so Unix metadata is not available
var extractor = new Extractor();
var path = Path.Combine(Directory.GetCurrentDirectory(), "TestData", "TestDataArchives", "TestData.iso");
var results = await extractor.ExtractAsync(path, new ExtractorOptions() { Recurse = false }).ToListAsync();

Assert.NotEmpty(results);
foreach (var entry in results)
{
// Without RockRidge extensions, metadata should be null
Assert.Null(entry.Metadata);
}
}

[Fact]
public void IsoEntries_MetadataIsNullWithoutRockRidge_Sync()
{
var extractor = new Extractor();
var path = Path.Combine(Directory.GetCurrentDirectory(), "TestData", "TestDataArchives", "TestData.iso");
var results = extractor.Extract(path, new ExtractorOptions() { Recurse = false }).ToList();

Assert.NotEmpty(results);
foreach (var entry in results)
{
Assert.Null(entry.Metadata);
}
}

[Fact]
public async Task IsoRockRidgeEntries_HaveMetadata()
{
// TestDataRockRidge.iso has RockRidge extensions with Unix permissions
var extractor = new Extractor();
var path = Path.Combine(Directory.GetCurrentDirectory(), "TestData", "TestDataArchives", "TestDataRockRidge.iso");
var results = await extractor.ExtractAsync(path, new ExtractorOptions() { Recurse = false }).ToListAsync();

Assert.NotEmpty(results);
foreach (var entry in results)
{
Assert.NotNull(entry.Metadata);
Assert.NotNull(entry.Metadata!.Mode);
Assert.NotNull(entry.Metadata.Uid);
Assert.NotNull(entry.Metadata.Gid);
}
}

[Fact]
public void IsoRockRidgeEntries_HaveMetadata_Sync()
{
var extractor = new Extractor();
var path = Path.Combine(Directory.GetCurrentDirectory(), "TestData", "TestDataArchives", "TestDataRockRidge.iso");
var results = extractor.Extract(path, new ExtractorOptions() { Recurse = false }).ToList();

Assert.NotEmpty(results);
foreach (var entry in results)
{
Assert.NotNull(entry.Metadata);
Assert.NotNull(entry.Metadata!.Mode);
Assert.NotNull(entry.Metadata.Uid);
Assert.NotNull(entry.Metadata.Gid);
}
}

[Fact]
public async Task VhdxNtfsEntries_HaveWindowsMetadata()
{
// TestData.vhdx contains an NTFS file system that implements IDosFileSystem and IWindowsFileSystem
var extractor = new Extractor();
var path = Path.Combine(Directory.GetCurrentDirectory(), "TestData", "TestDataArchives", "TestData.vhdx");
var results = await extractor.ExtractAsync(path, new ExtractorOptions() { Recurse = false }).ToListAsync();

Assert.NotEmpty(results);
foreach (var entry in results)
{
Assert.NotNull(entry.Metadata);
// NTFS provides Windows file attributes
Assert.NotNull(entry.Metadata!.FileAttributes);
// NTFS provides security descriptors
Assert.NotNull(entry.Metadata.SecurityDescriptorSddl);
Assert.Contains("D:", entry.Metadata.SecurityDescriptorSddl); // DACL present
// NTFS does not provide Unix metadata
Assert.Null(entry.Metadata.Mode);
Assert.Null(entry.Metadata.Uid);
Assert.Null(entry.Metadata.Gid);
}
}

[Fact]
public void VhdxNtfsEntries_HaveWindowsMetadata_Sync()
{
var extractor = new Extractor();
var path = Path.Combine(Directory.GetCurrentDirectory(), "TestData", "TestDataArchives", "TestData.vhdx");
var results = extractor.Extract(path, new ExtractorOptions() { Recurse = false }).ToList();

Assert.NotEmpty(results);
foreach (var entry in results)
{
Assert.NotNull(entry.Metadata);
Assert.NotNull(entry.Metadata!.FileAttributes);
Assert.NotNull(entry.Metadata.SecurityDescriptorSddl);
Assert.Null(entry.Metadata.Mode);
}
}
}
3 changes: 3 additions & 0 deletions RecursiveExtractor.Tests/RecursiveExtractor.Tests.csproj
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Expand Up @@ -165,6 +165,9 @@
<None Update="TestData\TestDataArchives\TestData.iso">
<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</None>
<None Update="TestData\TestDataArchives\TestDataRockRidge.iso">
<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</None>
<None Update="TestData\TestDataArchives\TestData.rar">
<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</None>
Expand Down
Binary file added RecursiveExtractor.Tests/TestData/TestDataArchives/TestDataRockRidge.iso
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98 changes: 98 additions & 0 deletions RecursiveExtractor/Extractors/DiscCommon.cs
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Expand Up @@ -14,6 +14,102 @@ public static class DiscCommon
{
private static readonly NLog.Logger Logger = NLog.LogManager.GetCurrentClassLogger();

/// <summary>
/// Tries to extract file metadata from a DiscUtils file system entry.
/// For file systems implementing <see cref="IUnixFileSystem"/> (Ext, Xfs, Btrfs, HfsPlus),
/// returns permissions, UID, and GID.
/// For file systems implementing <see cref="IDosFileSystem"/> (NTFS, FAT, WIM),
/// returns Windows file attributes.
/// For file systems implementing <see cref="IWindowsFileSystem"/> (NTFS, WIM),
Comment on lines +19 to +23
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Copilot AI Feb 14, 2026

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The XML doc comment lists examples of IUnixFileSystem implementations (Ext/Xfs/Btrfs/HfsPlus) but this helper is also used for ISO via DiscUtils.Iso9660.CDReader, which implements IUnixFileSystem only when RockRidge metadata is present. Consider updating the comment to include CDReader/ISO and note the RockRidge requirement (or clarify that the list is non-exhaustive) to avoid misleading future readers.

Suggested change
/// For file systems implementing <see cref="IUnixFileSystem"/> (Ext, Xfs, Btrfs, HfsPlus),
/// returns permissions, UID, and GID.
/// For file systems implementing <see cref="IDosFileSystem"/> (NTFS, FAT, WIM),
/// returns Windows file attributes.
/// For file systems implementing <see cref="IWindowsFileSystem"/> (NTFS, WIM),
/// For file systems implementing <see cref="IUnixFileSystem"/> (such as Ext, Xfs, Btrfs, HfsPlus,
/// and ISO images via <c>DiscUtils.Iso9660.CDReader</c> when RockRidge extensions are present),
/// returns permissions, UID, and GID.
/// For file systems implementing <see cref="IDosFileSystem"/> (such as NTFS, FAT, WIM),
/// returns Windows file attributes.
/// For file systems implementing <see cref="IWindowsFileSystem"/> (such as NTFS, WIM),

Copilot uses AI. Check for mistakes.
/// also returns the security descriptor in SDDL format.
/// Returns null for file systems that support none of these interfaces.
/// </summary>
/// <param name="fs">The opened disc file system</param>
/// <param name="filePath">Path of the file within the file system</param>
/// <returns>Populated <see cref="FileEntryMetadata"/> or null when not available</returns>
internal static FileEntryMetadata? TryGetFileMetadata(DiscFileSystem fs, string filePath)
{
FileEntryMetadata? metadata = null;

if (fs is IUnixFileSystem unixFs)
{
try
{
var info = unixFs.GetUnixFileInfo(filePath);
metadata = new FileEntryMetadata
{
Mode = (long)info.Permissions,
Uid = info.UserId,
Gid = info.GroupId
};
}
catch (Exception e)
{
Logger.Debug(e, "Could not retrieve Unix metadata for {0}", filePath);
}
}

if (fs is IDosFileSystem dosFs)
{
try
{
var winInfo = dosFs.GetFileStandardInformation(filePath);
metadata ??= new FileEntryMetadata();
metadata.FileAttributes = winInfo.FileAttributes;
}
catch (Exception e)
{
Logger.Debug(e, "Could not retrieve DOS file attributes for {0}", filePath);
}
}

if (fs is IWindowsFileSystem windowsFs)
{
try
{
var securityDescriptor = windowsFs.GetSecurity(filePath);
if (securityDescriptor != null)
{
metadata ??= new FileEntryMetadata();
metadata.SecurityDescriptorSddl = securityDescriptor.GetSddlForm(
DiscUtils.Core.WindowsSecurity.AccessControl.AccessControlSections.All);
}
}
catch (Exception e)
{
Logger.Debug(e, "Could not retrieve security descriptor for {0}", filePath);
}
}

return metadata;
}

/// <summary>
/// Pre-collects metadata for all files while the file system is still open.
/// Used by extractors (e.g., ISO) where the file system is disposed before files are processed.
/// </summary>
/// <param name="fs">The opened disc file system</param>
/// <param name="fileInfos">The file entries to collect metadata for</param>
/// <returns>A dictionary mapping file paths to metadata, or null if the file system does not support metadata</returns>
internal static Dictionary<string, FileEntryMetadata>? CollectMetadata(DiscFileSystem fs, DiscFileInfo[] fileInfos)
{
if (fs is not IUnixFileSystem && fs is not IDosFileSystem && fs is not IWindowsFileSystem)
{
return null;
}

var result = new Dictionary<string, FileEntryMetadata>();
foreach (var fi in fileInfos)
{
var metadata = TryGetFileMetadata(fs, fi.FullName);
if (metadata != null)
{
result[fi.FullName] = metadata;
}
}
return result;
}

/// <summary>
/// Dump the FileEntries from a Logical Volume asynchronously
/// </summary>
Expand Down Expand Up @@ -59,6 +155,7 @@ public static async IAsyncEnumerable<FileEntry> DumpLogicalVolumeAsync(LogicalVo
if (fileStream != null && fi != null)
{
var newFileEntry = await FileEntry.FromStreamAsync($"{volume.Identity}{Path.DirectorySeparatorChar}{fi.FullName}", fileStream, parent, fi.CreationTime, fi.LastWriteTime, fi.LastAccessTime, memoryStreamCutoff: options.MemoryStreamCutoff).ConfigureAwait(false);
newFileEntry.Metadata = TryGetFileMetadata(fs, file);
if (options.Recurse || topLevel)
{
await foreach (var entry in Context.ExtractAsync(newFileEntry, options, governor, false))
Expand Down Expand Up @@ -124,6 +221,7 @@ public static IEnumerable<FileEntry> DumpLogicalVolume(LogicalVolumeInfo volume,
if (fileStream != null)
{
var newFileEntry = new FileEntry($"{volume.Identity}{Path.DirectorySeparatorChar}{file}", fileStream, parent, false, creation, modification, access, memoryStreamCutoff: options.MemoryStreamCutoff);
newFileEntry.Metadata = TryGetFileMetadata(fs, file);
if (options.Recurse || topLevel)
{
foreach (var extractedFile in Context.Extract(newFileEntry, options, governor, false))
Expand Down
12 changes: 12 additions & 0 deletions RecursiveExtractor/Extractors/IsoExtractor.cs
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Expand Up @@ -31,11 +31,13 @@ public IsoExtractor(Extractor context)
public async IAsyncEnumerable<FileEntry> ExtractAsync(FileEntry fileEntry, ExtractorOptions options, ResourceGovernor governor, bool topLevel = true)
{
DiscUtils.DiscFileInfo[]? entries = null;
Dictionary<string, FileEntryMetadata>? metadataByPath = null;
var failed = false;
try
{
using var cd = new CDReader(fileEntry.Content, true);
entries = cd.Root.GetFiles("*.*", SearchOption.AllDirectories).ToArray();
metadataByPath = DiscCommon.CollectMetadata(cd, entries);
}
catch (Exception e)
{
Expand Down Expand Up @@ -69,6 +71,10 @@ public async IAsyncEnumerable<FileEntry> ExtractAsync(FileEntry fileEntry, Extra
{
var name = fileInfo.FullName.Replace('/', Path.DirectorySeparatorChar);
var newFileEntry = await FileEntry.FromStreamAsync(name, stream, fileEntry, fileInfo.CreationTime, fileInfo.LastWriteTime, fileInfo.LastAccessTime, memoryStreamCutoff: options.MemoryStreamCutoff).ConfigureAwait(false);
if (metadataByPath != null && metadataByPath.TryGetValue(fileInfo.FullName, out var entryMetadata))
{
newFileEntry.Metadata = entryMetadata;
}
if (options.Recurse || topLevel)
{
await foreach (var entry in Context.ExtractAsync(newFileEntry, options, governor, false))
Expand All @@ -92,11 +98,13 @@ public async IAsyncEnumerable<FileEntry> ExtractAsync(FileEntry fileEntry, Extra
public IEnumerable<FileEntry> Extract(FileEntry fileEntry, ExtractorOptions options, ResourceGovernor governor, bool topLevel = true)
{
DiscUtils.DiscFileInfo[]? entries = null;
Dictionary<string, FileEntryMetadata>? metadataByPath = null;
var failed = false;
try
{
using var cd = new CDReader(fileEntry.Content, true);
entries = cd.Root.GetFiles("*.*", SearchOption.AllDirectories).ToArray();
metadataByPath = DiscCommon.CollectMetadata(cd, entries);
}
catch(Exception e)
{
Expand Down Expand Up @@ -130,6 +138,10 @@ public IEnumerable<FileEntry> Extract(FileEntry fileEntry, ExtractorOptions opti
{
var name = fileInfo.FullName.Replace('/', Path.DirectorySeparatorChar);
var newFileEntry = new FileEntry(name, stream, fileEntry, createTime: file.CreationTime, modifyTime: file.LastWriteTime, accessTime: file.LastAccessTime, memoryStreamCutoff: options.MemoryStreamCutoff);
if (metadataByPath != null && metadataByPath.TryGetValue(fileInfo.FullName, out var entryMetadata))
{
newFileEntry.Metadata = entryMetadata;
}
if (options.Recurse || topLevel)
{
foreach (var entry in Context.Extract(newFileEntry, options, governor, false))
Expand Down
12 changes: 12 additions & 0 deletions RecursiveExtractor/Extractors/UdfExtractor.cs
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Expand Up @@ -31,11 +31,13 @@ public UdfExtractor(Extractor context)
public async IAsyncEnumerable<FileEntry> ExtractAsync(FileEntry fileEntry, ExtractorOptions options, ResourceGovernor governor, bool topLevel = true)
{
DiscUtils.DiscFileInfo[]? entries = null;
Dictionary<string, FileEntryMetadata>? metadataByPath = null;
var failed = false;
try
{
using var cd = new UdfReader(fileEntry.Content);
entries = cd.Root.GetFiles("*.*", SearchOption.AllDirectories).ToArray();
metadataByPath = DiscCommon.CollectMetadata(cd, entries);
}
catch (Exception e)
{
Expand Down Expand Up @@ -69,6 +71,10 @@ public async IAsyncEnumerable<FileEntry> ExtractAsync(FileEntry fileEntry, Extra
{
var name = fileInfo.FullName.Replace('/', Path.DirectorySeparatorChar);
var newFileEntry = await FileEntry.FromStreamAsync(name, stream, fileEntry, fileInfo.CreationTime, fileInfo.LastWriteTime, fileInfo.LastAccessTime, memoryStreamCutoff: options.MemoryStreamCutoff).ConfigureAwait(false);
if (metadataByPath != null && metadataByPath.TryGetValue(fileInfo.FullName, out var entryMetadata))
{
newFileEntry.Metadata = entryMetadata;
}
if (options.Recurse || topLevel)
{
await foreach (var entry in Context.ExtractAsync(newFileEntry, options, governor, false))
Expand All @@ -92,11 +98,13 @@ public async IAsyncEnumerable<FileEntry> ExtractAsync(FileEntry fileEntry, Extra
public IEnumerable<FileEntry> Extract(FileEntry fileEntry, ExtractorOptions options, ResourceGovernor governor, bool topLevel = true)
{
DiscUtils.DiscFileInfo[]? entries = null;
Dictionary<string, FileEntryMetadata>? metadataByPath = null;
var failed = false;
try
{
using var cd = new UdfReader(fileEntry.Content);
entries = cd.Root.GetFiles("*.*", SearchOption.AllDirectories).ToArray();
metadataByPath = DiscCommon.CollectMetadata(cd, entries);
}
catch(Exception e)
{
Expand Down Expand Up @@ -130,6 +138,10 @@ public IEnumerable<FileEntry> Extract(FileEntry fileEntry, ExtractorOptions opti
{
var name = fileInfo.FullName.Replace('/', Path.DirectorySeparatorChar);
var newFileEntry = new FileEntry(name, stream, fileEntry, createTime: file.CreationTime, modifyTime: file.LastWriteTime, accessTime: file.LastAccessTime, memoryStreamCutoff: options.MemoryStreamCutoff);
if (metadataByPath != null && metadataByPath.TryGetValue(fileInfo.FullName, out var entryMetadata))
{
newFileEntry.Metadata = entryMetadata;
}
if (options.Recurse || topLevel)
{
foreach (var entry in Context.Extract(newFileEntry, options, governor, false))
Expand Down
2 changes: 2 additions & 0 deletions RecursiveExtractor/Extractors/WimExtractor.cs
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Expand Up @@ -58,6 +58,7 @@ public async IAsyncEnumerable<FileEntry> ExtractAsync(FileEntry fileEntry, Extra
{
var name = file.Replace('\\', Path.DirectorySeparatorChar);
var newFileEntry = await FileEntry.FromStreamAsync($"{image.FriendlyName}{Path.DirectorySeparatorChar}{name}", stream, fileEntry, memoryStreamCutoff: options.MemoryStreamCutoff).ConfigureAwait(false);
newFileEntry.Metadata = DiscCommon.TryGetFileMetadata(image, file);

if (options.Recurse || topLevel)
{
Expand Down Expand Up @@ -128,6 +129,7 @@ public IEnumerable<FileEntry> Extract(FileEntry fileEntry, ExtractorOptions opti
var name = file.Replace('\\', Path.DirectorySeparatorChar);

var newFileEntry = new FileEntry($"{image.FriendlyName}{Path.DirectorySeparatorChar}{name}", stream, fileEntry, memoryStreamCutoff: options.MemoryStreamCutoff);
newFileEntry.Metadata = DiscCommon.TryGetFileMetadata(image, file);
if (options.Recurse || topLevel)
{
foreach (var extractedFile in Context.Extract(newFileEntry, options, governor, false))
Expand Down
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