[F2FS] Implement directory operations.

Aaru.Filesystems/F2FS/DEntry.cs

@@ -27,6 +27,7 @@
 // ****************************************************************************/
 
 using System;
+using System.Collections.Generic;
 using System.Text;
 using Aaru.CommonTypes.Enums;
 using Aaru.Logging;
@@ -36,8 +37,43 @@ namespace Aaru.Filesystems;
 
 public sealed partial class F2FS
 {
+    /// <summary>Reads the directory entries for a given inode into a dictionary</summary>
+    /// <param name="nid">Node ID of the directory inode</param>
+    /// <param name="entries">Output dictionary mapping filename → inode number</param>
+    /// <returns>Error code indicating success or failure</returns>
+    ErrorNumber ReadDirectoryEntries(uint nid, out Dictionary<string, uint> entries)
+    {
+        entries = new Dictionary<string, uint>();
+
+        // Resolve inode block address via NAT
+        ErrorNumber errno = LookupNat(nid, out uint blockAddr);
+
+        if(errno != ErrorNumber.NoError) return errno;
+
+        if(blockAddr == 0) return ErrorNumber.InvalidArgument;
+
+        // Read the inode node block
+        errno = ReadBlock(blockAddr, out byte[] nodeBlock);
+
+        if(errno != ErrorNumber.NoError) return errno;
+
+        // Parse the inode
+        Inode inode = Marshal.ByteArrayToStructureLittleEndian<Inode>(nodeBlock);
+
+        // Validate it's a directory
+        if((inode.i_mode & 0xF000) != 0x4000) return ErrorNumber.NotDirectory;
+
+        // Check if this directory uses inline dentry
+        if((inode.i_inline & F2FS_INLINE_DENTRY) != 0)
+            ParseInlineDentry(inode, nodeBlock, entries);
+        else
+            errno = ParseRegularDentry(inode, entries);
+
+        return errno;
+    }
+
     /// <summary>Parses inline dentry from the inode's node block</summary>
-    void ParseInlineDentry(Inode inode, byte[] nodeBlock)
+    void ParseInlineDentry(Inode inode, byte[] nodeBlock, Dictionary<string, uint> entries)
     {
         // For inline dentry, the data is stored in the inode's i_addr area
         // The inline data starts after the extra attribute area (if present) + reserved word
@@ -98,16 +134,16 @@ public sealed partial class F2FS
         int dentryStart   = reservedEnd;
         int filenameStart = dentryStart + nrInlineDentry * 11;
 
-        ParseDentryBitmapEntries(nodeBlock, bitmapStart, dentryStart, filenameStart, nrInlineDentry);
+        ParseDentryBitmapEntries(nodeBlock, bitmapStart, dentryStart, filenameStart, nrInlineDentry, entries);
     }
 
     /// <summary>Parses regular (non-inline) dentry blocks from the inode's data blocks</summary>
-    ErrorNumber ParseRegularDentry(Inode inode)
+    ErrorNumber ParseRegularDentry(Inode inode, Dictionary<string, uint> entries)
     {
         // Number of data blocks = ceil(i_size / blockSize)
         ulong nPages = (inode.i_size + _blockSize - 1) / _blockSize;
 
-        AaruLogging.Debug(MODULE_NAME, "Reading {0} dentry blocks from root inode", nPages);
+        AaruLogging.Debug(MODULE_NAME, "Reading {0} dentry blocks", nPages);
 
         // Get the extra isize in uint32 count
         var extraIsize = 0;
@@ -158,7 +194,8 @@ public sealed partial class F2FS
                                      0,
                                      SIZE_OF_DENTRY_BITMAP + SIZE_OF_RESERVED,
                                      SIZE_OF_DENTRY_BITMAP + SIZE_OF_RESERVED + NR_DENTRY_IN_BLOCK * 11,
-                                     NR_DENTRY_IN_BLOCK);
+                                     NR_DENTRY_IN_BLOCK,
+                                     entries);
         }
 
         return ErrorNumber.NoError;
@@ -167,7 +204,8 @@ public sealed partial class F2FS
     /// <summary>
     ///     Parses dentry entries from a bitmap/dentry/filename layout (used by both inline and regular dentry blocks)
     /// </summary>
-    void ParseDentryBitmapEntries(byte[] data, int bitmapOffset, int dentryOffset, int filenameOffset, int maxDentries)
+    static void ParseDentryBitmapEntries(byte[] data,        int bitmapOffset, int dentryOffset, int filenameOffset,
+                                         int    maxDentries, Dictionary<string, uint> entries)
     {
         var bitPos = 0;
 
@@ -205,10 +243,8 @@ public sealed partial class F2FS
 
             string fileName = Encoding.UTF8.GetString(data, fnOffset, nameLen);
 
-            if(!string.IsNullOrEmpty(fileName) &&
-               fileName is not ("." or "..")   &&
-               !_rootDirectoryCache.ContainsKey(fileName))
-                _rootDirectoryCache[fileName] = ino;
+            if(!string.IsNullOrEmpty(fileName) && fileName is not ("." or "..") && !entries.ContainsKey(fileName))
+                entries[fileName] = ino;
 
             // Advance past the slots used by this entry
             int slots = (nameLen + 8 - 1) / 8; // GET_DENTRY_SLOTS

Aaru.Filesystems/F2FS/Dir.cs

@@ -0,0 +1,166 @@
+// /***************************************************************************
+// Aaru Data Preservation Suite
+// ----------------------------------------------------------------------------
+//
+// Filename       : Dir.cs
+// Author(s)      : Natalia Portillo <claunia@claunia.com>
+//
+// Component      : F2FS filesystem plugin.
+//
+// --[ License ] --------------------------------------------------------------
+//
+//     This library is free software; you can redistribute it and/or modify
+//     it under the terms of the GNU Lesser General Public License as
+//     published by the Free Software Foundation; either version 2.1 of the
+//     License, or (at your option) any later version.
+//
+//     This library is distributed in the hope that it will be useful, but
+//     WITHOUT ANY WARRANTY; without even the implied warranty of
+//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+//     Lesser General Public License for more details.
+//
+//     You should have received a copy of the GNU Lesser General Public
+//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
+//
+// ----------------------------------------------------------------------------
+// Copyright © 2011-2026 Natalia Portillo
+// ****************************************************************************/
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Aaru.CommonTypes.Enums;
+using Aaru.CommonTypes.Interfaces;
+using Aaru.Logging;
+
+namespace Aaru.Filesystems;
+
+public sealed partial class F2FS
+{
+    /// <inheritdoc />
+    public ErrorNumber OpenDir(string path, out IDirNode node)
+    {
+        node = null;
+
+        if(!_mounted) return ErrorNumber.AccessDenied;
+
+        // Normalize the path
+        string normalizedPath = path ?? "/";
+
+        if(normalizedPath is "" or ".") normalizedPath = "/";
+
+        // Root directory — return cached entries
+        if(normalizedPath == "/")
+        {
+            if(_rootDirectoryCache.Count == 0) return ErrorNumber.NoSuchFile;
+
+            node = new F2fsDirNode
+            {
+                Path     = "/",
+                Position = 0,
+                Entries  = _rootDirectoryCache.Keys.ToArray()
+            };
+
+            return ErrorNumber.NoError;
+        }
+
+        // Subdirectory traversal
+        string pathWithoutLeadingSlash = normalizedPath.StartsWith("/", StringComparison.Ordinal)
+                                             ? normalizedPath[1..]
+                                             : normalizedPath;
+
+        string[] pathComponents = pathWithoutLeadingSlash.Split('/', StringSplitOptions.RemoveEmptyEntries);
+
+        if(pathComponents.Length == 0) return ErrorNumber.InvalidArgument;
+
+        AaruLogging.Debug(MODULE_NAME, "OpenDir: Traversing path with {0} components", pathComponents.Length);
+
+        // Start from root directory cache
+        Dictionary<string, uint> currentEntries = _rootDirectoryCache;
+
+        // Traverse each path component
+        for(var p = 0; p < pathComponents.Length; p++)
+        {
+            string component = pathComponents[p];
+
+            AaruLogging.Debug(MODULE_NAME, "OpenDir: Navigating to component '{0}'", component);
+
+            // Skip "." and ".." during traversal
+            if(component is "." or "..") continue;
+
+            // Find the component in current directory
+            if(!currentEntries.TryGetValue(component, out uint inodeNumber))
+            {
+                AaruLogging.Debug(MODULE_NAME, "OpenDir: Component '{0}' not found in directory", component);
+
+                return ErrorNumber.NoSuchFile;
+            }
+
+            AaruLogging.Debug(MODULE_NAME, "OpenDir: Component '{0}' found with inode {1}", component, inodeNumber);
+
+            // Read directory contents for this inode
+            ErrorNumber errno = ReadDirectoryEntries(inodeNumber, out Dictionary<string, uint> childEntries);
+
+            if(errno != ErrorNumber.NoError)
+            {
+                AaruLogging.Debug(MODULE_NAME, "OpenDir: Error reading directory for '{0}': {1}", component, errno);
+
+                return errno;
+            }
+
+            // If this is the last component, create the directory node
+            if(p == pathComponents.Length - 1)
+            {
+                node = new F2fsDirNode
+                {
+                    Path     = normalizedPath,
+                    Position = 0,
+                    Entries  = childEntries.Keys.ToArray()
+                };
+
+                AaruLogging.Debug(MODULE_NAME,
+                                  "OpenDir: Opened directory '{0}' with {1} entries",
+                                  normalizedPath,
+                                  childEntries.Count);
+
+                return ErrorNumber.NoError;
+            }
+
+            // Not the last component — continue traversing
+            currentEntries = childEntries;
+        }
+
+        return ErrorNumber.NoSuchFile;
+    }
+
+    /// <inheritdoc />
+    public ErrorNumber CloseDir(IDirNode node)
+    {
+        if(node is not F2fsDirNode f2fsNode) return ErrorNumber.InvalidArgument;
+
+        f2fsNode.Position = -1;
+        f2fsNode.Entries  = null;
+
+        return ErrorNumber.NoError;
+    }
+
+    /// <inheritdoc />
+    public ErrorNumber ReadDir(IDirNode node, out string filename)
+    {
+        filename = null;
+
+        if(!_mounted) return ErrorNumber.AccessDenied;
+
+        if(node is not F2fsDirNode f2fsNode) return ErrorNumber.InvalidArgument;
+
+        if(f2fsNode.Position < 0) return ErrorNumber.InvalidArgument;
+
+        // End of directory
+        if(f2fsNode.Position >= f2fsNode.Entries.Length) return ErrorNumber.NoError;
+
+        // Get current filename and advance position
+        filename = f2fsNode.Entries[f2fsNode.Position++];
+
+        return ErrorNumber.NoError;
+    }
+}

Aaru.Filesystems/F2FS/Internal.cs

@@ -0,0 +1,47 @@
+// /***************************************************************************
+// Aaru Data Preservation Suite
+// ----------------------------------------------------------------------------
+//
+// Filename       : Internal.cs
+// Author(s)      : Natalia Portillo <claunia@claunia.com>
+//
+// Component      : F2FS filesystem plugin.
+//
+// --[ License ] --------------------------------------------------------------
+//
+//     This library is free software; you can redistribute it and/or modify
+//     it under the terms of the GNU Lesser General Public License as
+//     published by the Free Software Foundation; either version 2.1 of the
+//     License, or (at your option) any later version.
+//
+//     This library is distributed in the hope that it will be useful, but
+//     WITHOUT ANY WARRANTY; without even the implied warranty of
+//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+//     Lesser General Public License for more details.
+//
+//     You should have received a copy of the GNU Lesser General Public
+//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
+//
+// ----------------------------------------------------------------------------
+// Copyright © 2011-2026 Natalia Portillo
+// ****************************************************************************/
+
+using Aaru.CommonTypes.Interfaces;
+
+namespace Aaru.Filesystems;
+
+public sealed partial class F2FS
+{
+    /// <summary>Directory node for enumerating directory contents</summary>
+    sealed class F2fsDirNode : IDirNode
+    {
+        /// <summary>Current position in the directory enumeration (entry index)</summary>
+        internal int Position { get; set; }
+
+        /// <summary>Array of directory entry names in this directory</summary>
+        internal string[] Entries { get; set; }
+
+        /// <inheritdoc />
+        public string Path { get; init; }
+    }
+}

Aaru.Filesystems/F2FS/Mount.cs

@@ -211,68 +211,16 @@ public sealed partial class F2FS
     {
         AaruLogging.Debug(MODULE_NAME, "Loading root directory, root_ino={0}", _superblock.root_ino);
 
-        // Resolve root inode block address via NAT
-        ErrorNumber errno = LookupNat(_superblock.root_ino, out uint rootBlockAddr);
+        ErrorNumber errno = ReadDirectoryEntries(_superblock.root_ino, out Dictionary<string, uint> entries);
 
         if(errno != ErrorNumber.NoError)
         {
-            AaruLogging.Debug(MODULE_NAME, "Error looking up root inode in NAT: {0}", errno);
+            AaruLogging.Debug(MODULE_NAME, "Error reading root directory entries: {0}", errno);
 
             return errno;
         }
 
-        AaruLogging.Debug(MODULE_NAME, "Root inode block address: {0}", rootBlockAddr);
-
-        if(rootBlockAddr == 0)
-        {
-            AaruLogging.Debug(MODULE_NAME, "Root inode block address is NULL_ADDR");
-
-            return ErrorNumber.InvalidArgument;
-        }
-
-        // Read the root inode node block
-        errno = ReadBlock(rootBlockAddr, out byte[] nodeBlock);
-
-        if(errno != ErrorNumber.NoError)
-        {
-            AaruLogging.Debug(MODULE_NAME, "Error reading root inode block: {0}", errno);
-
-            return errno;
-        }
-
-        // Parse the inode from the node block
-        Inode rootInode = Marshal.ByteArrayToStructureLittleEndian<Inode>(nodeBlock);
-
-        // Validate it's a directory
-        // S_IFDIR = 0x4000 in POSIX mode bits
-        if((rootInode.i_mode & 0xF000) != 0x4000)
-        {
-            AaruLogging.Debug(MODULE_NAME, "Root inode is not a directory (mode: 0x{0:X4})", rootInode.i_mode);
-
-            return ErrorNumber.InvalidArgument;
-        }
-
-        AaruLogging.Debug(MODULE_NAME,
-                          "Root inode valid: mode=0x{0:X4}, size={1}, inline=0x{2:X2}",
-                          rootInode.i_mode,
-                          rootInode.i_size,
-                          rootInode.i_inline);
-
-        // Check if this directory uses inline dentry
-        if((rootInode.i_inline & F2FS_INLINE_DENTRY) != 0)
-        {
-            AaruLogging.Debug(MODULE_NAME, "Root directory uses inline dentry");
-
-            ParseInlineDentry(rootInode, nodeBlock);
-        }
-        else
-        {
-            AaruLogging.Debug(MODULE_NAME, "Root directory uses regular dentry blocks");
-
-            errno = ParseRegularDentry(rootInode);
-
-            if(errno != ErrorNumber.NoError) return errno;
-        }
+        foreach(KeyValuePair<string, uint> kvp in entries) _rootDirectoryCache[kvp.Key] = kvp.Value;
 
         AaruLogging.Debug(MODULE_NAME, "Root directory loaded, {0} entries cached", _rootDirectoryCache.Count);
 

Aaru.Filesystems/F2FS/Unimplemented.cs

@@ -60,13 +60,4 @@ public sealed partial class F2FS
     /// <inheritdoc />
     public ErrorNumber ReadFile(IFileNode node, long length, byte[] buffer, out long read) =>
         throw new NotImplementedException();
-
-    /// <inheritdoc />
-    public ErrorNumber OpenDir(string path, out IDirNode node) => throw new NotImplementedException();
-
-    /// <inheritdoc />
-    public ErrorNumber CloseDir(IDirNode node) => throw new NotImplementedException();
-
-    /// <inheritdoc />
-    public ErrorNumber ReadDir(IDirNode node, out string filename) => throw new NotImplementedException();
 }