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https://github.com/aaru-dps/Aaru.git
synced 2026-02-04 08:54:40 +00:00
[BeFS] Move ParseDirectoryBTree to another file.
This commit is contained in:
@@ -27,7 +27,9 @@
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// ****************************************************************************/
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using System;
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using System.Collections.Generic;
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using Aaru.CommonTypes.Enums;
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using Aaru.Helpers;
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using Aaru.Logging;
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using Marshal = Aaru.Helpers.Marshal;
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@@ -37,73 +39,134 @@ namespace Aaru.Filesystems;
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/// <summary>Implements detection of the Be (new) filesystem</summary>
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public sealed partial class BeFS
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{
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/// <summary>Parses the directory B+tree structure from a data stream</summary>
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/// <remarks>
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/// Reads the B+tree header from the start of the data stream, validates it,
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/// reads the root node, and traverses the tree to extract all directory entries
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/// which are then cached for later retrieval.
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/// </remarks>
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/// <param name="dataStream">The data stream containing the B+tree data</param>
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/// <returns>Error code indicating success or failure</returns>
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private ErrorNumber ParseDirectoryBTree(data_stream dataStream)
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/// <summary>Parses a directory's B+tree and returns all entries</summary>
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private ErrorNumber ParseDirectoryBTree(data_stream dataStream, out Dictionary<string, long> entries)
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{
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AaruLogging.Debug(MODULE_NAME, "Parsing directory B+tree from data stream...");
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AaruLogging.Debug(MODULE_NAME, "Filesystem endianness: {0}", _littleEndian ? "Little-endian" : "Big-endian");
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entries = [];
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// Read B+tree header from position 0 of the data stream
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// Read B+tree header
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ErrorNumber errno = ReadFromDataStream(dataStream, 0, 32, out byte[] headerData);
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if(errno != ErrorNumber.NoError)
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{
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AaruLogging.Debug(MODULE_NAME, "Error reading B+tree header: {0}", errno);
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return errno;
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}
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AaruLogging.Debug(MODULE_NAME,
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"B+tree header raw bytes: {0}",
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BitConverter.ToString(headerData, 0, Math.Min(32, headerData.Length)));
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if(errno != ErrorNumber.NoError) return errno;
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bt_header btHeader = _littleEndian
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? Marshal.ByteArrayToStructureLittleEndian<bt_header>(headerData)
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: Marshal.ByteArrayToStructureBigEndian<bt_header>(headerData);
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AaruLogging.Debug(MODULE_NAME,
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"B+tree header: magic=0x{0:X8}, node_size={1}, root_ptr={2}",
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btHeader.magic,
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btHeader.node_size,
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btHeader.node_root_pointer);
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if(btHeader.magic != BTREE_MAGIC) return ErrorNumber.InvalidArgument;
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// Validate B+tree header
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if(btHeader.magic != BTREE_MAGIC)
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// Traverse B+tree to collect all entries
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const long BEFS_BT_INVAL = unchecked((long)0xFFFFFFFFFFFFFFFF);
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long nodeOffset = btHeader.node_root_pointer;
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while(nodeOffset != 0 && nodeOffset != BEFS_BT_INVAL)
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{
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AaruLogging.Debug(MODULE_NAME,
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"Invalid B+tree magic! Expected 0x{0:X8}, got 0x{1:X8}",
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BTREE_MAGIC,
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btHeader.magic);
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errno = ReadFromDataStream(dataStream, nodeOffset, btHeader.node_size, out byte[] nodeData);
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return ErrorNumber.InvalidArgument;
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if(errno != ErrorNumber.NoError) return errno;
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bt_node_hdr nodeHeader = _littleEndian
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? Marshal.ByteArrayToStructureLittleEndian<bt_node_hdr>(nodeData)
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: Marshal.ByteArrayToStructureBigEndian<bt_node_hdr>(nodeData);
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bool isLeafNode = nodeHeader.overflow_link == BEFS_BT_INVAL;
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if(isLeafNode)
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{
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// Parse leaf node entries
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const int headerSize = 28;
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int keyDataStart = headerSize;
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int keyDataEnd = keyDataStart + nodeHeader.keys_length;
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int keyLengthIndexStart = keyDataEnd + 3 & ~3;
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int valueDataStart = keyLengthIndexStart + nodeHeader.node_keys * 2;
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var keyOffset = 0;
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for(var i = 0; i < nodeHeader.node_keys; i++)
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{
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int offsetIndex = keyLengthIndexStart + i * 2;
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// Bounds check before reading
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if(offsetIndex + 2 > nodeData.Length)
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{
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AaruLogging.Debug(MODULE_NAME,
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"Offset index {0} extends beyond node data length {1}",
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offsetIndex + 2,
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nodeData.Length);
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break;
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}
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ushort keyEndOffset = _littleEndian
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? BitConverter.ToUInt16(nodeData, offsetIndex)
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: BigEndianBitConverter.ToUInt16(nodeData, offsetIndex);
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int keyStart = keyDataStart + keyOffset;
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int keyLength = keyEndOffset - keyOffset;
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// Validate key length - must be positive and reasonable
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if(keyLength <= 0 || keyLength > 256)
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{
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AaruLogging.Debug(MODULE_NAME,
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"Invalid key length at index {0}: keyOffset={1}, keyEndOffset={2}, calculated length={3}",
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i,
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keyOffset,
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keyEndOffset,
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keyLength);
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break;
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}
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// Validate key data is within the key data section
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if(keyStart < keyDataStart || keyStart + keyLength > keyDataEnd)
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{
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AaruLogging.Debug(MODULE_NAME,
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"Key data out of bounds at index {0}: start={1}, length={2}, range=[{3},{4}]",
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i,
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keyStart,
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keyLength,
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keyDataStart,
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keyDataEnd);
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break;
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}
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int valueIndex = valueDataStart + i * 8;
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// Bounds check for value data
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if(valueIndex + 8 > nodeData.Length)
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{
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AaruLogging.Debug(MODULE_NAME,
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"Value index {0} extends beyond node data length {1}",
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valueIndex + 8,
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nodeData.Length);
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break;
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}
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long inodeNumber = _littleEndian
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? BitConverter.ToInt64(nodeData, valueIndex)
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: BigEndianBitConverter.ToInt64(nodeData, valueIndex);
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string keyName = _encoding.GetString(nodeData, keyStart, keyLength);
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// Filter out "." (current directory) and ".." (parent directory)
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// These should not be cached as they cause infinite loops during path traversal
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if(keyName != "." && keyName != ".." && !entries.ContainsKey(keyName))
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entries[keyName] = inodeNumber;
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keyOffset = keyEndOffset;
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}
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}
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// Move to next sibling
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if(nodeHeader.right_link != 0 && nodeHeader.right_link != BEFS_BT_INVAL)
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nodeOffset = nodeHeader.right_link;
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else
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break;
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}
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if(btHeader.node_size != 1024)
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{
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AaruLogging.Debug(MODULE_NAME, "Invalid B+tree node size! Expected 1024, got {0}", btHeader.node_size);
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return ErrorNumber.InvalidArgument;
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}
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// Read root node from data stream
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errno = ReadFromDataStream(dataStream, btHeader.node_root_pointer, btHeader.node_size, out byte[] rootNodeData);
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if(errno != ErrorNumber.NoError)
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{
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AaruLogging.Debug(MODULE_NAME, "Error reading root B+tree node: {0}", errno);
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return errno;
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}
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// Traverse B+tree
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return TraverseBTree(dataStream, btHeader, btHeader.node_root_pointer, rootNodeData);
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return ErrorNumber.NoError;
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}
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/// <summary>Recursively traverses a B+tree node and its siblings</summary>
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@@ -31,9 +31,7 @@ using System.Collections.Generic;
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using System.Linq;
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using Aaru.CommonTypes.Enums;
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using Aaru.CommonTypes.Interfaces;
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using Aaru.Helpers;
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using Aaru.Logging;
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using Marshal = Aaru.Helpers.Marshal;
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namespace Aaru.Filesystems;
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@@ -235,134 +233,4 @@ public sealed partial class BeFS
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// In BeFS, the mode field contains Unix-style permission bits
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// S_IFDIR = 0x4000
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(inode.mode & 0xF000) == 0x4000;
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/// <summary>Parses a directory's B+tree and returns all entries</summary>
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private ErrorNumber ParseDirectoryBTree(data_stream dataStream, out Dictionary<string, long> entries)
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{
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entries = [];
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// Read B+tree header
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ErrorNumber errno = ReadFromDataStream(dataStream, 0, 32, out byte[] headerData);
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if(errno != ErrorNumber.NoError) return errno;
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bt_header btHeader = _littleEndian
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? Marshal.ByteArrayToStructureLittleEndian<bt_header>(headerData)
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: Marshal.ByteArrayToStructureBigEndian<bt_header>(headerData);
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if(btHeader.magic != BTREE_MAGIC) return ErrorNumber.InvalidArgument;
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// Traverse B+tree to collect all entries
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const long BEFS_BT_INVAL = unchecked((long)0xFFFFFFFFFFFFFFFF);
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long nodeOffset = btHeader.node_root_pointer;
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while(nodeOffset != 0 && nodeOffset != BEFS_BT_INVAL)
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{
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errno = ReadFromDataStream(dataStream, nodeOffset, btHeader.node_size, out byte[] nodeData);
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if(errno != ErrorNumber.NoError) return errno;
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bt_node_hdr nodeHeader = _littleEndian
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? Marshal.ByteArrayToStructureLittleEndian<bt_node_hdr>(nodeData)
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: Marshal.ByteArrayToStructureBigEndian<bt_node_hdr>(nodeData);
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bool isLeafNode = nodeHeader.overflow_link == BEFS_BT_INVAL;
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if(isLeafNode)
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{
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// Parse leaf node entries
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const int headerSize = 28;
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int keyDataStart = headerSize;
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int keyDataEnd = keyDataStart + nodeHeader.keys_length;
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int keyLengthIndexStart = keyDataEnd + 3 & ~3;
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int valueDataStart = keyLengthIndexStart + nodeHeader.node_keys * 2;
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var keyOffset = 0;
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for(var i = 0; i < nodeHeader.node_keys; i++)
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{
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int offsetIndex = keyLengthIndexStart + i * 2;
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// Bounds check before reading
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if(offsetIndex + 2 > nodeData.Length)
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{
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AaruLogging.Debug(MODULE_NAME,
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"Offset index {0} extends beyond node data length {1}",
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offsetIndex + 2,
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nodeData.Length);
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break;
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}
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ushort keyEndOffset = _littleEndian
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? BitConverter.ToUInt16(nodeData, offsetIndex)
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: BigEndianBitConverter.ToUInt16(nodeData, offsetIndex);
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int keyStart = keyDataStart + keyOffset;
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int keyLength = keyEndOffset - keyOffset;
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// Validate key length - must be positive and reasonable
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if(keyLength <= 0 || keyLength > 256)
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{
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AaruLogging.Debug(MODULE_NAME,
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"Invalid key length at index {0}: keyOffset={1}, keyEndOffset={2}, calculated length={3}",
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i,
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keyOffset,
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keyEndOffset,
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keyLength);
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break;
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}
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// Validate key data is within the key data section
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if(keyStart < keyDataStart || keyStart + keyLength > keyDataEnd)
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{
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AaruLogging.Debug(MODULE_NAME,
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"Key data out of bounds at index {0}: start={1}, length={2}, range=[{3},{4}]",
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i,
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keyStart,
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keyLength,
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keyDataStart,
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keyDataEnd);
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break;
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}
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int valueIndex = valueDataStart + i * 8;
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// Bounds check for value data
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if(valueIndex + 8 > nodeData.Length)
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{
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AaruLogging.Debug(MODULE_NAME,
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"Value index {0} extends beyond node data length {1}",
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valueIndex + 8,
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nodeData.Length);
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break;
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}
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long inodeNumber = _littleEndian
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? BitConverter.ToInt64(nodeData, valueIndex)
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: BigEndianBitConverter.ToInt64(nodeData, valueIndex);
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string keyName = _encoding.GetString(nodeData, keyStart, keyLength);
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// Filter out "." (current directory) and ".." (parent directory)
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// These should not be cached as they cause infinite loops during path traversal
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if(keyName != "." && keyName != ".." && !entries.ContainsKey(keyName))
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entries[keyName] = inodeNumber;
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keyOffset = keyEndOffset;
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}
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}
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// Move to next sibling
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if(nodeHeader.right_link != 0 && nodeHeader.right_link != BEFS_BT_INVAL)
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nodeOffset = nodeHeader.right_link;
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else
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break;
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}
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return ErrorNumber.NoError;
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}
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}
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