Files
Aaru-aaru-dps/Aaru.Filesystems/ProDOS/File.cs

537 lines
18 KiB
C#

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename : File.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Apple ProDOS 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 Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Interfaces;
using Aaru.CommonTypes.Structs;
using Aaru.Logging;
using Marshal = Aaru.Helpers.Marshal;
namespace Aaru.Filesystems;
/// <inheritdoc />
public sealed partial class ProDOSPlugin
{
/// <inheritdoc />
public ErrorNumber OpenFile(string path, out IFileNode node)
{
node = null;
if(!_mounted) return ErrorNumber.AccessDenied;
AaruLogging.Debug(MODULE_NAME, "OpenFile: path='{0}'", path);
// Get the entry for this path
ErrorNumber errno = GetEntryForPath(path, out CachedEntry entry);
if(errno != ErrorNumber.NoError)
{
AaruLogging.Debug(MODULE_NAME, "Error getting entry for path: {0}", errno);
return errno;
}
// Cannot open directories
if(entry.IsDirectory)
{
AaruLogging.Debug(MODULE_NAME, "Cannot open directory as file");
return ErrorNumber.IsDirectory;
}
// Get file length - for extended files, we need to read the extended key block
long fileLength;
byte storageType = entry.StorageType;
ushort keyBlock = entry.KeyBlock;
if(storageType == EXTENDED_FILE_TYPE)
{
errno = ReadBlock(entry.KeyBlock, out byte[] extBlock);
if(errno != ErrorNumber.NoError)
{
AaruLogging.Debug(MODULE_NAME, "Error reading extended key block: {0}", errno);
return errno;
}
ExtendedKeyBlock extKeyBlock = Marshal.ByteArrayToStructureLittleEndian<ExtendedKeyBlock>(extBlock);
// Data fork size
fileLength = extKeyBlock.data_fork.eof[0] |
extKeyBlock.data_fork.eof[1] << 8 |
extKeyBlock.data_fork.eof[2] << 16;
// Use data fork's storage type and key block
storageType = (byte)(extKeyBlock.data_fork.storage_type >> 4);
keyBlock = extKeyBlock.data_fork.key_block;
}
else
fileLength = entry.Eof;
// Create file node
var fileNode = new ProDosFileNode
{
Path = path,
Entry = entry,
Length = fileLength,
Offset = 0,
// Store effective storage type and key block (possibly from extended file's data fork)
EffectiveStorageType = storageType,
EffectiveKeyBlock = keyBlock
};
// Pre-load index block(s) for sapling and tree files
errno = LoadIndexBlocks(fileNode);
if(errno != ErrorNumber.NoError)
{
AaruLogging.Debug(MODULE_NAME, "Error loading index blocks: {0}", errno);
return errno;
}
node = fileNode;
AaruLogging.Debug(MODULE_NAME, "OpenFile successful: path='{0}', size={1}", path, fileLength);
return ErrorNumber.NoError;
}
/// <inheritdoc />
public ErrorNumber CloseFile(IFileNode node)
{
if(node is not ProDosFileNode proDosNode) return ErrorNumber.InvalidArgument;
AaruLogging.Debug(MODULE_NAME, "CloseFile: path='{0}'", proDosNode.Path);
// Clear cached data
proDosNode.IndexBlock = null;
proDosNode.MasterIndexBlock = null;
proDosNode.CachedBlockData = null;
proDosNode.CachedBlockIndex = -1;
proDosNode.Offset = -1;
return ErrorNumber.NoError;
}
/// <inheritdoc />
public ErrorNumber ReadFile(IFileNode node, long length, byte[] buffer, out long read)
{
read = 0;
if(!_mounted) return ErrorNumber.AccessDenied;
if(node is not ProDosFileNode proDosNode) return ErrorNumber.InvalidArgument;
if(proDosNode.Offset < 0) return ErrorNumber.InvalidArgument;
if(buffer == null || buffer.Length < length) return ErrorNumber.InvalidArgument;
AaruLogging.Debug(MODULE_NAME,
"ReadFile: path='{0}', offset={1}, length={2}",
proDosNode.Path,
proDosNode.Offset,
length);
// Check if at or past EOF
if(proDosNode.Offset >= proDosNode.Length)
{
AaruLogging.Debug(MODULE_NAME, "ReadFile: at EOF");
return ErrorNumber.NoError;
}
// Adjust length if it would read past EOF
long bytesToRead = length;
if(proDosNode.Offset + bytesToRead > proDosNode.Length) bytesToRead = proDosNode.Length - proDosNode.Offset;
if(bytesToRead <= 0) return ErrorNumber.NoError;
// Read data block by block
long bufferOffset = 0;
while(bytesToRead > 0)
{
// Calculate which block we need
var blockIndex = (int)(proDosNode.Offset / 512);
var offsetInBlock = (int)(proDosNode.Offset % 512);
// Get the data block
ErrorNumber errno = ReadFileBlock(proDosNode, blockIndex, out byte[] blockData);
if(errno != ErrorNumber.NoError)
{
AaruLogging.Debug(MODULE_NAME, "Error reading file block {0}: {1}", blockIndex, errno);
return errno;
}
// Calculate how much to copy from this block
var bytesFromBlock = (int)Math.Min(bytesToRead, 512 - offsetInBlock);
// Copy to output buffer
Array.Copy(blockData, offsetInBlock, buffer, bufferOffset, bytesFromBlock);
bufferOffset += bytesFromBlock;
proDosNode.Offset += bytesFromBlock;
bytesToRead -= bytesFromBlock;
read += bytesFromBlock;
}
AaruLogging.Debug(MODULE_NAME, "ReadFile successful: read {0} bytes, new offset={1}", read, proDosNode.Offset);
return ErrorNumber.NoError;
}
/// <inheritdoc />
public ErrorNumber Stat(string path, out FileEntryInfo stat)
{
stat = null;
if(!_mounted) return ErrorNumber.AccessDenied;
// Handle root directory specially
if(string.IsNullOrEmpty(path) || path == "/" || path == ".")
{
stat = new FileEntryInfo
{
Attributes = FileAttributes.Directory,
BlockSize = 512,
Blocks = 4, // Volume directory is always 4 blocks
CreationTime = _creationTime,
Inode = 2, // Root directory starts at block 2
Links = 1,
Mode = 0x16D, // drwxrw-r-x
DeviceNo = 0,
GID = 0,
UID = 0,
Length = 4 * 512
};
return ErrorNumber.NoError;
}
// Get the entry for this path
ErrorNumber errno = GetEntryForPath(path, out CachedEntry entry);
if(errno != ErrorNumber.NoError) return errno;
stat = new FileEntryInfo
{
BlockSize = 512,
CreationTime = entry.CreationTime,
LastWriteTime = entry.ModificationTime,
Links = 1,
DeviceNo = 0,
GID = 0,
UID = 0
};
// Directory
if(entry.IsDirectory)
{
stat.Attributes = FileAttributes.Directory;
stat.Blocks = entry.BlocksUsed;
stat.Inode = entry.KeyBlock;
stat.Length = entry.BlocksUsed * 512;
stat.Mode = 0x16D; // drwxrw-r-x
return ErrorNumber.NoError;
}
// File
stat.Inode = entry.KeyBlock;
// Set attributes
stat.Attributes = FileAttributes.File;
if((entry.Access & READ_ATTRIBUTE) == 0) stat.Attributes |= FileAttributes.Hidden;
if((entry.Access & WRITE_ATTRIBUTE) == 0) stat.Attributes |= FileAttributes.ReadOnly;
if((entry.Access & BACKUP_ATTRIBUTE) != 0) stat.Attributes |= FileAttributes.Archive;
// Calculate mode from access flags
uint mode = 0x8000; // Regular file
if((entry.Access & READ_ATTRIBUTE) != 0) mode |= 0x124; // r--r--r--
if((entry.Access & WRITE_ATTRIBUTE) != 0) mode |= 0x92; // -w--w--w-
stat.Mode = mode;
// For extended files (with resource fork), read the extended key block to get data fork size
if(entry.StorageType == EXTENDED_FILE_TYPE)
{
errno = ReadBlock(entry.KeyBlock, out byte[] extBlock);
if(errno != ErrorNumber.NoError) return errno;
ExtendedKeyBlock extKeyBlock = Marshal.ByteArrayToStructureLittleEndian<ExtendedKeyBlock>(extBlock);
// Data fork size (per user requirement: data fork mandates file size)
var dataForkEof = (uint)(extKeyBlock.data_fork.eof[0] |
extKeyBlock.data_fork.eof[1] << 8 |
extKeyBlock.data_fork.eof[2] << 16);
stat.Length = dataForkEof;
stat.Blocks = extKeyBlock.data_fork.blocks_used;
}
else
{
// Non-extended file: use entry's EOF and blocks_used
stat.Length = entry.Eof;
stat.Blocks = entry.BlocksUsed;
}
return ErrorNumber.NoError;
}
/// <summary>Loads index blocks for sapling and tree storage types</summary>
ErrorNumber LoadIndexBlocks(ProDosFileNode fileNode)
{
byte storageType = fileNode.EffectiveStorageType;
ushort keyBlock = fileNode.EffectiveKeyBlock;
switch(storageType)
{
case SEEDLING_FILE_TYPE:
// Seedling: key block is the single data block, no index needed
return ErrorNumber.NoError;
case SAPLING_FILE_TYPE:
{
// Sapling: key block is an indirect block containing up to 256 block pointers
ErrorNumber errno = ReadBlock(keyBlock, out byte[] indexBlock);
if(errno != ErrorNumber.NoError) return errno;
// Parse the indirect block (LSB in first 256 bytes, MSB in second 256 bytes)
fileNode.IndexBlock = new ushort[256];
for(var i = 0; i < 256; i++)
fileNode.IndexBlock[i] = (ushort)(indexBlock[i] | indexBlock[256 + i] << 8);
return ErrorNumber.NoError;
}
case TREE_FILE_TYPE:
{
// Tree: key block is a master (double-indirect) block
ErrorNumber errno = ReadBlock(keyBlock, out byte[] masterBlock);
if(errno != ErrorNumber.NoError) return errno;
// Parse the master index block
fileNode.MasterIndexBlock = new ushort[256];
for(var i = 0; i < 256; i++)
fileNode.MasterIndexBlock[i] = (ushort)(masterBlock[i] | masterBlock[256 + i] << 8);
return ErrorNumber.NoError;
}
default:
AaruLogging.Debug(MODULE_NAME, "Unknown storage type: 0x{0:X2}", storageType);
return ErrorNumber.InvalidArgument;
}
}
/// <summary>Reads a specific data block from a file</summary>
ErrorNumber ReadFileBlock(ProDosFileNode fileNode, int blockIndex, out byte[] blockData)
{
blockData = null;
// Check if this block is already cached
if(fileNode.CachedBlockIndex == blockIndex && fileNode.CachedBlockData != null)
{
blockData = fileNode.CachedBlockData;
return ErrorNumber.NoError;
}
byte storageType = fileNode.EffectiveStorageType;
ushort diskBlock;
switch(storageType)
{
case SEEDLING_FILE_TYPE:
// Seedling: key block is the single data block
if(blockIndex != 0) return ErrorNumber.InvalidArgument;
diskBlock = fileNode.EffectiveKeyBlock;
break;
case SAPLING_FILE_TYPE:
// Sapling: index block contains block pointers
if(blockIndex >= 256) return ErrorNumber.InvalidArgument;
diskBlock = fileNode.IndexBlock[blockIndex];
break;
case TREE_FILE_TYPE:
{
// Tree: master index -> index block -> data block
int masterIndex = blockIndex / 256;
int indexOffset = blockIndex % 256;
if(masterIndex >= 256) return ErrorNumber.InvalidArgument;
ushort indexBlockPtr = fileNode.MasterIndexBlock[masterIndex];
// Sparse block (index block pointer is 0)
if(indexBlockPtr == 0)
{
blockData = new byte[512];
fileNode.CachedBlockIndex = blockIndex;
fileNode.CachedBlockData = blockData;
return ErrorNumber.NoError;
}
// Load the index block (cache it for subsequent reads in the same range)
if(fileNode.IndexBlock == null || fileNode.CachedIndexBlockNumber != masterIndex)
{
ErrorNumber errno = ReadBlock(indexBlockPtr, out byte[] indexBlock);
if(errno != ErrorNumber.NoError) return errno;
fileNode.IndexBlock = new ushort[256];
for(var i = 0; i < 256; i++)
fileNode.IndexBlock[i] = (ushort)(indexBlock[i] | indexBlock[256 + i] << 8);
fileNode.CachedIndexBlockNumber = masterIndex;
}
diskBlock = fileNode.IndexBlock[indexOffset];
break;
}
default:
return ErrorNumber.InvalidArgument;
}
// Sparse block (block pointer is 0 means unallocated = zeros)
if(diskBlock == 0)
{
blockData = new byte[512];
fileNode.CachedBlockIndex = blockIndex;
fileNode.CachedBlockData = blockData;
return ErrorNumber.NoError;
}
// Read the actual data block
ErrorNumber readErrno = ReadBlock(diskBlock, out blockData);
if(readErrno != ErrorNumber.NoError) return readErrno;
// Cache the block
fileNode.CachedBlockIndex = blockIndex;
fileNode.CachedBlockData = blockData;
return ErrorNumber.NoError;
}
/// <summary>Gets a cached entry for the given path</summary>
/// <param name="path">Path to the file or directory</param>
/// <param name="entry">Output cached entry</param>
/// <returns>Error number</returns>
ErrorNumber GetEntryForPath(string path, out CachedEntry entry)
{
entry = null;
if(string.IsNullOrEmpty(path) || path == "/" || path == ".") return ErrorNumber.IsDirectory;
string[] pathComponents = path.Split('/', StringSplitOptions.RemoveEmptyEntries);
if(pathComponents.Length == 0) return ErrorNumber.IsDirectory;
// Start from root directory cache
Dictionary<string, CachedEntry> currentDir = _rootDirectoryCache;
for(var i = 0; i < pathComponents.Length; i++)
{
string component = pathComponents[i];
if(component is "." or "..") continue;
if(!currentDir.TryGetValue(component, out CachedEntry currentEntry)) return ErrorNumber.NoSuchFile;
// Last component - return this entry
if(i == pathComponents.Length - 1)
{
entry = currentEntry;
return ErrorNumber.NoError;
}
// Intermediate component must be a directory
if(!currentEntry.IsDirectory) return ErrorNumber.NotDirectory;
// Read subdirectory contents
ErrorNumber errno =
ReadDirectoryContents(currentEntry.KeyBlock, false, out Dictionary<string, CachedEntry> subDir);
if(errno != ErrorNumber.NoError) return errno;
currentDir = subDir;
}
return ErrorNumber.NoSuchFile;
}
/// <summary>Applies GS/OS case bits to a filename</summary>
static string ApplyCaseBits(string name, ushort caseBits)
{
if((caseBits & 0x8000) == 0) return name;
char[] chars = name.ToCharArray();
var bit = 0x4000;
for(var i = 0; i < chars.Length && bit > 0; i++)
{
if((caseBits & bit) != 0) chars[i] = char.ToLower(chars[i]);
bit >>= 1;
}
return new string(chars);
}
}