NTFSish system improvements to symlink/reparse points

IAbstractRecord Filename standardization for NTFSish as well

Author: mitchcapper

Library/DiscUtils.Core/NativeFileSystem.cs

@@ -806,15 +806,11 @@ public IEnumerable<IAbstractRecord> AllEntries {
 
 	}
 	internal class NativeAbstractRecord : IAbstractRecord {
-		public NativeAbstractRecord(NativeFileSystem fs, String path){
-			info = new FileInfo(Path.Combine(fs.BasePath,path));
-			IsDirectory = false;
-			FileName = fs.CleanItems(info.FullName);
-			this.fs  = fs;
+		public NativeAbstractRecord(NativeFileSystem fs, String path) : this (fs, new FileInfo(Path.Combine(fs.BasePath, path)), false) {
 		}
 		internal NativeAbstractRecord(NativeFileSystem fs, System.IO.FileSystemInfo info, bool isDirectory){
 			this.info = info;
-			IsDirectory = true;
+			IsDirectory = isDirectory;
 			FileName = fs.CleanItems(info.FullName);
 			this.fs  = fs;
 		}

Library/DiscUtils.Core/ReparsePoint.cs

@@ -36,7 +36,7 @@ public sealed class ReparsePoint
     /// </summary>
     /// <param name="tag">The defined reparse point tag.</param>
     /// <param name="content">The reparse point's content.</param>
-    public ReparsePoint(int tag, byte[] content)
+    public ReparsePoint(uint tag, byte[] content)
     {
         Tag = tag;
         Content = content;
@@ -50,22 +50,25 @@ public ReparsePoint(int tag, byte[] content)
     /// <summary>
     /// Gets or sets the defined reparse point tag.
     /// </summary>
-    public int Tag { get; set; }
+    public uint Tag { get; set; }
 	// https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/c8e77b37-3909-4fe6-a4ea-2b9d423b1ee4
-	private const int IO_REPARSE_TAG_MOUNT_POINT = unchecked((int)0xA0000003);
-	private const int IO_REPARSE_TAG_SYMLINK = unchecked((int)0xA000000C);
+	private const uint IO_REPARSE_TAG_MOUNT_POINT = 0xA0000003;
+	private const uint IO_REPARSE_TAG_SYMLINK = 0xA000000C;
 	// https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-fscc/b41f1cbf-10df-4a47-98d4-1c52a833d913
 	private enum SymlinkFlags : int {
 		 FullpathName = 0,
 		 SYMLINK_FLAG_RELATIVE = 1
 	}
+	public static bool IsValidSymlinkTag(uint tag) {
+		return tag == IO_REPARSE_TAG_SYMLINK || tag == IO_REPARSE_TAG_MOUNT_POINT;
+	}
 	internal string ParseSymlink(String originalPath) {
 
 		var reparsePoint = this;
 
 		using var stream = new MemoryStream(reparsePoint.Content);
 		using var reader = new BinaryReader(stream);
-		if (reparsePoint.Tag != IO_REPARSE_TAG_SYMLINK && reparsePoint.Tag != IO_REPARSE_TAG_MOUNT_POINT)
+		if (! IsValidSymlinkTag(reparsePoint.Tag) )
 			throw new IOException($"Reparse point on {originalPath} is not a symlink or mount point (tag: 0x{reparsePoint.Tag:X8})");
 
 		var substNameOffset = reader.ReadUInt16();

Library/DiscUtils.Core/Vfs/IAbstractRecord.cs

@@ -9,7 +9,7 @@ public interface IAbstractRecord {
 		DateTime CreationTimeUtc { get; }
 		FileAttributes FileAttributes { get; }
 	/// <summary>
-	/// the SubPath relative to the IAbstractDirectory that returned it
+	/// the SubPath relative to the parent IAbstractDirectory
 	/// </summary>
 		string FileName { get; }
 		bool IsDirectory { get; }

Library/DiscUtils.Ntfs/NtfsAbstractRecord.cs

@@ -14,9 +14,10 @@ internal class NtfsAbstractRecord(NtfsFileSystem fileSystem, FileNameRecord Reco
 
 	public DateTime CreationTimeUtc => Record.CreationTime;
 	public FileAttributes FileAttributes => Record.FileAttributes;
-	public string FileName => FilePath;
+	public string FileName => Record.FileName;
 	public bool IsDirectory => Record.Flags.HasFlag(NtfsFileAttributes.Directory);
-	public bool IsSymlink => Record.Flags.HasFlag(NtfsFileAttributes.ReparsePoint);
+	public bool IsSymlink => Record.Flags.HasFlag(NtfsFileAttributes.ReparsePoint) && ReparsePoint.IsValidSymlinkTag(Record.EASizeOrReparsePointTag);
+	
 	public DateTime LastAccessTimeUtc => Record.LastAccessTime;
 	public DateTime LastWriteTimeUtc => Record.ModificationTime;
 	public long FileId => (long)FileIndex.Value;
@@ -26,6 +27,7 @@ internal class NtfsAbstractRecord(NtfsFileSystem fileSystem, FileNameRecord Reco
 
 	protected NtfsFileSystem FileSystem { get; } = fileSystem;
 	protected FileNameRecord Record { get; } = Record;
+	public String FullPath => FilePath;
 	protected FileRecordReference FileIndex { get; } = FileIndex;
 	DateTime IVfsFile.CreationTimeUtc { get; set; }
 	FileAttributes IVfsFile.FileAttributes { get; set; }
@@ -35,7 +37,7 @@ internal class NtfsAbstractRecord(NtfsFileSystem fileSystem, FileNameRecord Reco
 	DateTime IVfsFile.LastWriteTimeUtc { get; set; }
 
 	public IAbstractDirectory GetAsAbstractDirectory() {
-
+		
 		if (!IsDirectory)
 			throw new InvalidOperationException("Not a directory");
 		var file = AsFile();

Library/DiscUtils.Ntfs/NtfsFileSystem.cs

@@ -1426,7 +1426,7 @@ public ReparsePoint GetReparsePoint(string path)
 
                 using var contentStream = stream.Value.Open(FileAccess.Read);
                 var rp = contentStream.ReadStruct<ReparsePointRecord>((int)contentStream.Length);
-                return new ReparsePoint((int)rp.Tag, rp.Content);
+                return new ReparsePoint(rp.Tag, rp.Content);
             }
         }
 
@@ -2674,12 +2674,15 @@ public override IAbstractRecord GetAbstractRecord(string path) {
      public override string GetSymlinkTarget(IAbstractRecord dirEntry) {
          if (!dirEntry.IsSymlink)
              throw new ArgumentException($"dirEntry is not a symlink");
+		 if (dirEntry is not NtfsAbstractRecord ntfsDirEntry)
+			throw new ArgumentException($"dirEntry is not an NtfsAbstractRecord");
+		
 
-         var reparsePoint = GetReparsePoint(dirEntry.FileName);
+		var reparsePoint = GetReparsePoint(ntfsDirEntry.FullPath);
          if (reparsePoint == null)
-             throw new IOException($"Unable to read reparse point for {dirEntry.FileName}");
+             throw new IOException($"Unable to read reparse point for {ntfsDirEntry.FullPath}");
 
-         return reparsePoint.ParseSymlink(dirEntry.FileName);
+         return reparsePoint.ParseSymlink(ntfsDirEntry.FullPath);
      }
     /// <summary>
     /// A plugin system for handling reparse points. Handlers for specific tags can register here

Library/DiscUtils.Wim/WimFileSystem.cs

@@ -118,7 +118,7 @@ public ReparsePoint GetReparsePoint(string path)
 
         using var s = _file.OpenResourceStream(hdr);
         var buffer = s.ReadExactly((int)s.Length);
-        return new ReparsePoint((int)dirEntry.ReparseTag, buffer);
+        return new ReparsePoint(dirEntry.ReparseTag, buffer);
     }
 
     /// <summary>
@@ -750,14 +750,15 @@ private IEnumerable<string> DoSearch(string path, Func<string, bool> filter, boo
 	internal class WimAbstractRecord (WimFileSystem FileSystem, DirectoryEntry Record, String Path) : IAbstractRecord{
 		public DateTime CreationTimeUtc => DateTime.FromFileTimeUtc(Record.CreationTime); // Entry has creationTime
 		public FileAttributes FileAttributes => Record.Attributes;
-		public string FileName => Path;
+		public string FileName => Record.FileName;
+		public string FullPath => Path;
 		public bool IsDirectory => Record.Attributes.HasFlag(FileAttributes.Directory);
-		public bool IsSymlink  => Record.Attributes.HasFlag(FileAttributes.ReparsePoint);
+		public bool IsSymlink  => Record.Attributes.HasFlag(FileAttributes.ReparsePoint) && ReparsePoint.IsValidSymlinkTag(Record.ReparseTag);
 		public DateTime LastAccessTimeUtc => DateTime.FromFileTimeUtc(Record.LastAccessTime);
 		public DateTime LastWriteTimeUtc => DateTime.FromFileTimeUtc(Record.LastWriteTime);
 		public long FileId => BitConverter.ToInt64(Record.Hash, 0) ^ BitConverter.ToInt64(Record.Hash, 8) ^ BitConverter.ToInt32(Record.Hash, 16);
 		public long FileSize => FileSystem._file.LocateResource(Record.GetStreamHash(default))?.OriginalSize ?? 0;
-		public SparseStream FileContent => FileSystem.OpenFile(FileName, FileMode.Open, FileAccess.Read); 
+		public SparseStream FileContent => FileSystem.OpenFile(Path, FileMode.Open, FileAccess.Read); 
 		protected WimFileSystem FileSystem { get; } = FileSystem;
 		protected DirectoryEntry Record{ get; } = Record;
 
@@ -771,17 +772,19 @@ internal class WimAbstractDirectory(WimFileSystem FileSystem, DirectoryEntry Rec
 
 	}
 	private IAbstractRecord GetEntryAsAbstractRecord(DirectoryEntry record, String Path) => (record.Attributes.HasFlag(FileAttributes.Directory) && record.Attributes.HasFlag(FileAttributes.ReparsePoint) == false) ?
-			new WimAbstractDirectory(this,record,Path) :
-			new WimAbstractRecord(this,record,Path);
+			new WimAbstractDirectory(this,record, Path) :
+			new WimAbstractRecord(this,record, Path);
 	public override IAbstractRecord GetAbstractRecord(string path)=> GetEntryAsAbstractRecord(GetEntry(path),String.IsNullOrWhiteSpace(path) ? "/" : "");
 	public override string GetSymlinkTarget(IAbstractRecord dirEntry) {
 		if (!dirEntry.IsSymlink)
 			throw new ArgumentException($"dirEntry is not a symlink");
+		if (dirEntry is not WimAbstractRecord dirEntryWim)
+			throw new ArgumentException($"dirEntry is not a WimAbstractRecord");
 
-		var reparsePoint = GetReparsePoint(dirEntry.FileName);
+		var reparsePoint = GetReparsePoint(dirEntryWim.FullPath);
 		if (reparsePoint == null)
-			throw new IOException($"Unable to read reparse point for {dirEntry.FileName}");
+			throw new IOException($"Unable to read reparse point for {dirEntryWim.FullPath}");
 
-		return reparsePoint.ParseSymlink(dirEntry.FileName);
+		return reparsePoint.ParseSymlink(dirEntryWim.FullPath);
 	}
 }