wehub-resource-sync
680845cb1c
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1415 lines
69 KiB
Swift
1415 lines
69 KiB
Swift
//===----------------------------------------------------------------------===//
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// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//===----------------------------------------------------------------------===//
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// swiftlint: disable discouraged_direct_init shorthand_operator syntactic_sugar
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import ContainerizationArchive
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import ContainerizationOS
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import Foundation
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import SystemPackage
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extension EXT4 {
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/// The `EXT4.Formatter` class provides methods to format a block device with the ext4 filesystem.
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/// It allows customization of block size and maximum disk size.
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public class Formatter {
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private let logBlockSize: UInt32
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var blockSize: UInt32 { 1024 << logBlockSize }
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private var size: UInt64
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private let groupDescriptorSize: UInt32 = 32
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private var blocksPerGroup: UInt32 {
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blockSize * 8
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}
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private var maxInodesPerGroup: UInt32 {
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blockSize * 8 // limited by inode bitmap
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}
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private var groupsPerDescriptorBlock: UInt32 {
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blockSize / groupDescriptorSize
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}
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// internally accessed by journal setup
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var blockCount: UInt32 {
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((size - 1) / blockSize) + 1
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}
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private var groupCount: UInt32 {
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(blockCount - 1) / blocksPerGroup + 1
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}
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private var groupDescriptorBlocks: UInt32 {
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((groupCount - 1) / groupsPerDescriptorBlock + 1) * 32
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}
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/// Initializes an ext4 filesystem formatter.
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///
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/// This constructor creates an instance of the ext4 formatter designed to format a block device
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/// with the ext4 filesystem. The formatter takes the path to the destination block device and
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/// the desired block size of the filesystem as parameters.
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///
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/// - Parameters:
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/// - devicePath: The path to the block device where the ext4 filesystem will be created.
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/// - blockSize: The filesystem block size in bytes. Must be a power of two in the set
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/// {1024, 2048, 4096}. Defaults to 4096.
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/// - minDiskSize: The minimum usable capacity for the filesystem. When a journal is
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/// configured, the actual image size will be larger than this value by the journal size.
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/// - journal: The JBD2 journal size and mode, or nil for an unjournalled filesystem.
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///
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/// - Note: This ext4 formatter is designed for creating block devices out of container images and does not support all the
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/// features and options available in the full ext4 filesystem implementation. It focuses
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/// on the core functionality required for formatting a block device with ext4.
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///
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/// - Important: Ensure that the destination block device is accessible and has sufficient permissions
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/// for formatting. The formatting process will erase all existing data on the device.
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public init(_ devicePath: FilePath, blockSize: UInt32 = 4096, minDiskSize: UInt64 = 256.kib(), journal: JournalConfig? = nil) throws {
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/// The constructor performs the following steps:
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///
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/// 1. Creates the first 10 inodes:
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/// - Inode 2 is reserved for the root directory ('/').
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/// - Inodes 1 and 3-10 are reserved for other special purposes.
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///
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/// 2. Marks inode 11 as the first inode available for consumption by files, directories, sockets,
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/// FIFOs, etc.
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///
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/// 3. Initializes a directory tree with the root directory pointing to inode 2.
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///
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/// 4. Moves the file descriptor to the start of the block where file metadata and data can be
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/// written, which is located past the filesystem superblocks and group descriptor blocks.
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///
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/// 5. Creates a "/lost+found" directory to satisfy the requirements of e2fsck (ext2/3/4 filesystem
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/// checker).
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guard blockSize >= 1024 && blockSize <= 4096 && blockSize.nonzeroBitCount == 1 else {
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throw Error.invalidBlockSize(blockSize)
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}
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guard minDiskSize / UInt64(blockSize) <= UInt64(UInt32.max) else {
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throw Error.cannotResizeFS(minDiskSize)
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}
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self.logBlockSize = UInt32(blockSize.trailingZeroBitCount) - 10
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if !FileManager.default.fileExists(atPath: devicePath.description) {
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_ = FileManager.default.createFile(atPath: devicePath.description, contents: nil)
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}
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guard let fileHandle = FileHandle(forWritingTo: devicePath) else {
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throw Error.notFound(devicePath)
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}
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self.handle = fileHandle
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self.size = minDiskSize
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// make this a 0 byte file
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guard ftruncate(self.handle.fileDescriptor, 0) == 0 else {
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throw Error.cannotTruncateFile(devicePath)
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}
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// make it a sparse file
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guard lseek(self.handle.fileDescriptor, off_t(self.size - 1), 0) == self.size - 1 else {
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throw Error.cannotCreateSparseFile(devicePath)
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}
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let zero: [UInt8] = [0]
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try self.handle.write(contentsOf: zero)
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// step #1
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self.inodes = [
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Ptr(Inode()), // defective block inode
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Ptr(Inode.Root()),
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]
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// reserved inodes
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for _ in 2..<EXT4.FirstInode - 1 {
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inodes.append(Ptr(Inode()))
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}
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// step #2
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self.tree = FileTree(EXT4.RootInode, "/")
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self.journalConfig = journal
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// skip past the superblock and block descriptor table
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try self.seek(block: self.groupDescriptorBlocks + 1)
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// lost+found directory is required for e2fsck to pass
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try self.create(path: FilePath("/lost+found"), mode: Inode.Mode(.S_IFDIR, 0o700))
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}
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// Creates a hard link at the path specified by `link` that points to the same file or directory as the path specified by `target`.
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//
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// A hard link is a directory entry that points to the same inode as another directory entry. It allows multiple paths to refer to the same file on the file system.
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//
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// - `link`: The path at which to create the new hard link.
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// - `target`: The path of the existing file or directory to which the hard link should point.
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//
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// Throws an error if `target` path does not exist, or `target` is a directory.
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public func link(
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link: FilePath,
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target: FilePath
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) throws {
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// ensure that target exists
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guard let targetPtr = self.tree.lookup(path: target) else {
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throw Error.notFound(target)
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}
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let targetNode = targetPtr.pointee
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let targetInodePtr = self.inodes[Int(targetNode.inode) - 1]
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var targetInode = targetInodePtr.pointee
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// ensure that target is not a directory since hardlinks cannot be
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// created to directories
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if targetInode.mode.isDir() {
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throw Error.cannotCreateHardlinksToDirTarget(link)
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}
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targetInode.linksCount += 1
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targetInodePtr.pointee = targetInode
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let parentPath: FilePath = link.dir
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if self.tree.lookup(path: link) != nil {
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try self.unlink(path: link)
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}
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// create all predecessors recursively
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try self.create(path: parentPath, mode: Inode.Mode(.S_IFDIR, 0o755), recursion: true)
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guard let parentTreeNodePtr = self.tree.lookup(path: parentPath) else {
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throw Error.notFound(parentPath)
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}
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let parentTreeNode = parentTreeNodePtr.pointee
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let parentInodePtr = self.inodes[Int(parentTreeNode.inode) - 1]
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let parentInode = parentInodePtr.pointee
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guard parentInode.linksCount < EXT4.MaxLinks else {
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throw Error.maximumLinksExceeded(parentPath)
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}
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let linkTreeNodePtr = Ptr(
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FileTree.FileTreeNode(
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inode: InodeNumber(2), // this field is ignored, using 2 so array operations dont panic
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name: link.base,
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parent: parentTreeNodePtr,
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children: [],
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blocks: nil,
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link: targetNode.inode
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))
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parentTreeNode.children.append(linkTreeNodePtr)
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parentTreeNodePtr.pointee = parentTreeNode
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}
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// Deletes the file or directory at the specified path from the filesystem.
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//
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// It performs the following actions
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// - set link count of the file's inode to 0
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// - recursively set link count to 0 for its children
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// - free the inode
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// - free data blocks
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// - remove directory entry
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//
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// - `path`: The `FilePath` specifying the path of the file or directory to delete.
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public func unlink(path: FilePath, directoryWhiteout: Bool = false) throws {
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guard let pathPtr = self.tree.lookup(path: path),
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let parentPtr = self.tree.lookup(path: path.dir)
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else {
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// We are being asked to unlink something that does not exist. Ignore
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return
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}
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let pathNode = pathPtr.pointee
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let inodeNumber = Int(pathNode.inode) - 1
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let pathInodePtr = self.inodes[inodeNumber]
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let pathInode = pathInodePtr.pointee
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if directoryWhiteout && !pathInode.mode.isDir() {
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throw Error.notDirectory(path)
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}
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// Iterative breath-first traversal of the FileTree to prevent recursion attacks
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var queue: [(parent: Ptr<FileTree.FileTreeNode>, entry: Ptr<FileTree.FileTreeNode>)] = pathNode.children.map { (pathPtr, $0) }
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var head: Int = 0
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while head < queue.count {
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let currNode = queue[head].entry
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for childPtr in currNode.pointee.children {
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queue.append((currNode, childPtr))
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}
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head += 1
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}
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for (parent, entry) in queue.reversed() {
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try _unlink(parentNodePtr: parent, pathNodePtr: entry)
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}
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guard !directoryWhiteout else {
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return
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}
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try _unlink(parentNodePtr: parentPtr, pathNodePtr: pathPtr)
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}
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private func _unlink(parentNodePtr: Ptr<FileTree.FileTreeNode>, pathNodePtr: Ptr<FileTree.FileTreeNode>) throws {
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let pathNode = pathNodePtr.pointee
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let pathComponent = pathNode.name
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let inodeNumber = Int(pathNode.inode) - 1
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let pathInodePtr = self.inodes[inodeNumber]
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var pathInode = pathInodePtr.pointee
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let parentNode = parentNodePtr.pointee
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let parentInodePtr = self.inodes[Int(parentNode.inode) - 1]
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var parentInode = parentInodePtr.pointee
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if pathInode.mode.isDir() {
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if parentInode.linksCount > 2 {
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parentInode.linksCount -= 1
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}
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}
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parentInodePtr.pointee = parentInode
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parentNode.children.removeAll { childPtr in
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childPtr.pointee.name == pathComponent
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}
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parentNodePtr.pointee = parentNode
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if let hardlink = pathNode.link {
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// the file we are deleting is a hardlink, decrement the link count
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let linkedInodePtr = self.inodes[Int(hardlink - 1)]
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var linkedInode = linkedInodePtr.pointee
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if linkedInode.linksCount > 1 {
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linkedInode.linksCount -= 1
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linkedInodePtr.pointee = linkedInode
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}
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}
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guard inodeNumber >= FirstInode else {
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// Free the inodes and the blocks related to the inode only if its valid
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return
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}
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if let blocks = pathNode.blocks {
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if !(blocks.start == blocks.end) {
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self.deletedBlocks.append((start: blocks.start, end: blocks.end))
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}
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}
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for block in pathNode.additionalBlocks ?? [] {
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self.deletedBlocks.append((start: block.start, end: block.end))
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}
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let now = Date().fs()
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pathInode = Inode()
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pathInode.dtime = now.lo
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pathInodePtr.pointee = pathInode
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}
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// Creates a file, directory, or symlink at the specified path, recursively creating parent directories if they don't already exist.
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//
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// - Parameters:
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// - path: The FilePath representing the path where the file, directory, or symlink should be created.
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// - link: An optional FilePath representing the target path for a symlink. If `nil`, a regular file or directory will be created. Preceding '/' should be omitted
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// - mode: The permissions to set for the created file, directory, or symlink.
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// - buf: A `ReadableStream` object providing the contents for the created file. Ignored when creating directories or symlinks.
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//
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// - Note:
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// - This function recursively creates parent directories if they don't already exist. The `uid` and `gid` of the created parent directories are set to the values of their parent's `uid` and `gid`.
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// - It is expected that the user sets the permissions explicitly later
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// - This function only supports creating files, directories, and symlinks. Attempting to create other types of file system objects will result in an error.
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// - In case of symlinks, the preceding '/' should be omitted
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//
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// - Example usage:
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// ```swift
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// let formatter = EXT4.Formatter(devicePath: "ext4.img")
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// // create a directory
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// try formatter.create(path: FilePath("/dir"),
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// mode: EXT4.Inode.Mode(.S_IFDIR, 0o700))
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//
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// // create a file
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// let inputStream = InputStream(data: "data".data(using: .utf8)!)
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// inputStream.open()
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// try formatter.create(path: FilePath("/dir/file"),
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// mode: EXT4.Inode.Mode(.S_IFREG, 0o755), buf: inputStream)
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// inputStream.close()
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//
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// // create a symlink
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// try formatter.create(path: FilePath("/symlink"), link: "/dir/file",
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// mode: EXT4.Inode.Mode(.S_IFLNK, 0o700))
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// ```
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public func create(
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path: FilePath,
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link: FilePath? = nil, // to create symbolic links
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mode: UInt16,
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ts: FileTimestamps = FileTimestamps(),
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buf: (any ReadableStream)? = nil,
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uid: UInt32? = nil,
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gid: UInt32? = nil,
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xattrs: [String: Data]? = nil,
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recursion: Bool = false,
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fileBuffer: UnsafeMutableBufferPointer<UInt8>? = nil
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) throws {
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if let nodePtr = self.tree.lookup(path: path) {
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let node = nodePtr.pointee
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let inodePtr = self.inodes[Int(node.inode) - 1]
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let inode = inodePtr.pointee
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// Allowed replace
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// -----------------------------
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//
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// Original Type File Directory Symlink
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// ----------------------------------------------
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// File | ✔ | ✘ | ✔
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// Directory | ✘ | ✔ | ✔
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// Symlink | ✔ | ✘ | ✔
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if mode.isDir() {
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if !inode.mode.isDir() {
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guard inode.mode.isLink() else {
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throw Error.notDirectory(path)
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}
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}
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// mkdir -p
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if path.base == node.name {
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guard !recursion else {
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return
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}
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// create a new tree node to replace this one
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var inode = inode
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inode.mode = mode
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if let uid {
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inode.uid = uid.lo
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inode.uidHigh = uid.hi
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}
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if let gid {
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inode.gid = gid.lo
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inode.gidHigh = gid.hi
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}
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inodePtr.pointee = inode
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return
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}
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} else if let _ = node.link { // ok to overwrite links
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try self.unlink(path: path)
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} else { // file can only be overwritten by another file
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if inode.mode.isDir() {
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guard mode.isLink() else { // unless it is a link, then it can be replaced by a dir
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throw Error.notFile(path)
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}
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// root cannot be replaced with a link
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if path.isRoot {
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throw Error.unsupportedFiletype
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}
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}
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try self.unlink(path: path)
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}
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}
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// create all predecessors recursively
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let parentPath: FilePath = path.dir
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try self.create(path: parentPath, mode: Inode.Mode(.S_IFDIR, 0o755), recursion: true)
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guard let parentTreeNodePtr = self.tree.lookup(path: parentPath) else {
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throw Error.notFound(parentPath)
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}
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let parentTreeNode = parentTreeNodePtr.pointee
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let parentInodePtr = self.inodes[Int(parentTreeNode.inode) - 1]
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var parentInode = parentInodePtr.pointee
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guard parentInode.linksCount < EXT4.MaxLinks else {
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throw Error.maximumLinksExceeded(parentPath)
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}
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let childInodePtr = Ptr(Inode())
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var childInode = Inode()
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var startBlock: UInt32 = 0
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var endBlock: UInt32 = 0
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defer { // update metadata
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childInodePtr.pointee = childInode
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parentInodePtr.pointee = parentInode
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self.inodes.append(childInodePtr)
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let childTreeNodePtr = Ptr(
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FileTree.FileTreeNode(
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inode: InodeNumber(self.inodes.count),
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name: path.base,
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parent: parentTreeNodePtr,
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children: [],
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blocks: (startBlock, endBlock)
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))
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parentTreeNode.children.append(childTreeNodePtr)
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parentTreeNodePtr.pointee = parentTreeNode
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}
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childInode.mode = mode
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// uid,gid
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if let uid {
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childInode.uid = UInt16(uid & 0xffff)
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childInode.uidHigh = UInt16((uid >> 16) & 0xffff)
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} else {
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childInode.uid = parentInode.uid
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childInode.uidHigh = parentInode.uidHigh
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}
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if let gid {
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childInode.gid = UInt16(gid & 0xffff)
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childInode.gidHigh = UInt16((gid >> 16) & 0xffff)
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} else {
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childInode.gid = parentInode.gid
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childInode.gidHigh = parentInode.gidHigh
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}
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if let xattrs, !xattrs.isEmpty {
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var state = FileXattrsState(
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inode: UInt32(self.inodes.count), inodeXattrCapacity: EXT4.InodeExtraSize, blockCapacity: blockSize)
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try state.add(ExtendedAttribute(name: "system.data", value: []))
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for (s, d) in xattrs {
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let attribute = ExtendedAttribute(name: s, value: [UInt8](d))
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try state.add(attribute)
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}
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if !state.inlineAttributes.isEmpty {
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var buffer: [UInt8] = .init(repeating: 0, count: Int(EXT4.InodeExtraSize))
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try state.writeInlineAttributes(buffer: &buffer)
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childInode.inlineXattrs = (
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buffer[0], buffer[1], buffer[2], buffer[3], buffer[4], buffer[5], buffer[6], buffer[7],
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buffer[8],
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buffer[9],
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buffer[10], buffer[11], buffer[12], buffer[13], buffer[14], buffer[15], buffer[16], buffer[17],
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buffer[18],
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buffer[19],
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buffer[20], buffer[21], buffer[22], buffer[23], buffer[24], buffer[25], buffer[26], buffer[27],
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buffer[28],
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buffer[29],
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buffer[30], buffer[31], buffer[32], buffer[33], buffer[34], buffer[35], buffer[36], buffer[37],
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buffer[38],
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buffer[39],
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buffer[40], buffer[41], buffer[42], buffer[43], buffer[44], buffer[45], buffer[46], buffer[47],
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buffer[48],
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buffer[49],
|
|
buffer[50], buffer[51], buffer[52], buffer[53], buffer[54], buffer[55], buffer[56], buffer[57],
|
|
buffer[58],
|
|
buffer[59],
|
|
buffer[60], buffer[61], buffer[62], buffer[63], buffer[64], buffer[65], buffer[66], buffer[67],
|
|
buffer[68],
|
|
buffer[69],
|
|
buffer[70], buffer[71], buffer[72], buffer[73], buffer[74], buffer[75], buffer[76], buffer[77],
|
|
buffer[78],
|
|
buffer[79],
|
|
buffer[80], buffer[81], buffer[82], buffer[83], buffer[84], buffer[85], buffer[86], buffer[87],
|
|
buffer[88],
|
|
buffer[89],
|
|
buffer[90], buffer[91], buffer[92], buffer[93], buffer[94], buffer[95]
|
|
)
|
|
}
|
|
if !state.blockAttributes.isEmpty {
|
|
var buffer: [UInt8] = .init(repeating: 0, count: Int(blockSize))
|
|
try state.writeBlockAttributes(buffer: &buffer)
|
|
if self.pos % self.blockSize != 0 {
|
|
try self.seek(block: self.currentBlock + 1)
|
|
}
|
|
childInode.xattrBlockLow = self.currentBlock
|
|
try self.handle.write(contentsOf: buffer)
|
|
childInode.blocksLow += 1
|
|
}
|
|
}
|
|
|
|
childInode.atime = ts.accessLo
|
|
childInode.atimeExtra = ts.accessHi
|
|
// ctime is the last time the inode was changed which is now
|
|
childInode.ctime = ts.nowLo
|
|
childInode.ctimeExtra = ts.nowHi
|
|
childInode.mtime = ts.modificationLo
|
|
childInode.mtimeExtra = ts.modificationHi
|
|
childInode.crtime = ts.creationLo
|
|
childInode.crtimeExtra = ts.creationHi
|
|
childInode.linksCount = 1
|
|
childInode.extraIsize = UInt16(EXT4.ExtraIsize)
|
|
// flags
|
|
childInode.flags = InodeFlag.hugeFile.rawValue
|
|
// size check
|
|
var size: UInt64 = 0
|
|
// align with block boundary
|
|
if self.pos % self.blockSize != 0 {
|
|
try self.seek(block: self.currentBlock + 1)
|
|
}
|
|
// dir
|
|
if childInode.mode.isDir() {
|
|
childInode.linksCount += 1
|
|
parentInode.linksCount += 1
|
|
// to pass e2fsck, the convention is to sort children
|
|
// before committing to disk. Therefore, we are deferring
|
|
// writing dentries until commit() is called
|
|
return
|
|
}
|
|
// symbolic link
|
|
if let link {
|
|
startBlock = self.currentBlock
|
|
let linkPath = link.bytes
|
|
if linkPath.count < 60 {
|
|
size += UInt64(linkPath.count)
|
|
var blockData: [UInt8] = .init(repeating: 0, count: 60)
|
|
for i in 0..<linkPath.count {
|
|
blockData[i] = linkPath[i]
|
|
}
|
|
childInode.block = (
|
|
blockData[0], blockData[1], blockData[2], blockData[3], blockData[4], blockData[5],
|
|
blockData[6],
|
|
blockData[7], blockData[8], blockData[9],
|
|
blockData[10], blockData[11], blockData[12], blockData[13], blockData[14], blockData[15],
|
|
blockData[16],
|
|
blockData[17], blockData[18], blockData[19],
|
|
blockData[20], blockData[21], blockData[22], blockData[23], blockData[24], blockData[25],
|
|
blockData[26],
|
|
blockData[27], blockData[28], blockData[29],
|
|
blockData[30], blockData[31], blockData[32], blockData[33], blockData[34], blockData[35],
|
|
blockData[36],
|
|
blockData[37], blockData[38], blockData[39],
|
|
blockData[40], blockData[41], blockData[42], blockData[43], blockData[44], blockData[45],
|
|
blockData[46],
|
|
blockData[47], blockData[48], blockData[49],
|
|
blockData[50], blockData[51], blockData[52], blockData[53], blockData[54], blockData[55],
|
|
blockData[56],
|
|
blockData[57], blockData[58], blockData[59]
|
|
)
|
|
} else {
|
|
try linkPath.withUnsafeBytes { buffer in
|
|
try withUnsafeLittleEndianBuffer(of: buffer) { b in
|
|
try self.handle.write(contentsOf: b)
|
|
}
|
|
size += UInt64(buffer.count)
|
|
}
|
|
}
|
|
if self.pos % self.blockSize != 0 {
|
|
try self.seek(block: self.currentBlock + 1)
|
|
}
|
|
endBlock = self.currentBlock
|
|
childInode.sizeLow = size.lo
|
|
childInode.sizeHigh = size.hi
|
|
childInode.mode |= 0o777
|
|
childInode.flags = 0
|
|
if linkPath.count < 60 {
|
|
childInode.blocksLow = 0
|
|
} else {
|
|
childInode = try self.writeExtents(childInode, (startBlock, endBlock))
|
|
childInode.blocksLow = 8
|
|
}
|
|
return
|
|
}
|
|
// regular file
|
|
if mode.isReg() {
|
|
startBlock = self.currentBlock
|
|
if let buf { // in case of empty files, this will be nil
|
|
let tempBuf: UnsafeMutablePointer<UInt8>
|
|
let bufferSize: Int
|
|
let shouldDeallocate: Bool
|
|
if let fileBuffer {
|
|
tempBuf = fileBuffer.baseAddress!
|
|
bufferSize = fileBuffer.count
|
|
shouldDeallocate = false
|
|
} else {
|
|
tempBuf = UnsafeMutablePointer<UInt8>.allocate(capacity: Int(self.blockSize))
|
|
bufferSize = Int(self.blockSize)
|
|
shouldDeallocate = true
|
|
}
|
|
defer {
|
|
if shouldDeallocate {
|
|
tempBuf.deallocate()
|
|
}
|
|
}
|
|
while case let block = buf.read(tempBuf, maxLength: bufferSize), block > 0 {
|
|
size += UInt64(block)
|
|
if size > EXT4.MaxFileSize {
|
|
throw Error.fileTooBig(size)
|
|
}
|
|
let data = UnsafeRawBufferPointer(start: tempBuf, count: block)
|
|
try withUnsafeLittleEndianBuffer(of: data) { b in
|
|
try self.handle.write(contentsOf: b)
|
|
}
|
|
}
|
|
}
|
|
if self.pos % self.blockSize != 0 {
|
|
try self.seek(block: self.currentBlock + 1)
|
|
}
|
|
endBlock = self.currentBlock
|
|
childInode.sizeLow = size.lo
|
|
childInode.sizeHigh = size.hi
|
|
childInode = try self.writeExtents(childInode, (startBlock, endBlock))
|
|
return
|
|
}
|
|
// FIFO, Socket and other types are not handled
|
|
throw Error.unsupportedFiletype
|
|
}
|
|
|
|
// Completes the formatting of an ext4 filesystem after writing the necessary structures.
|
|
//
|
|
// This function is responsible for finalizing the formatting process of an ext4 filesystem
|
|
// after the following structures have been written:
|
|
// - JBD2 journal (inode 8): Written first when a journal config is provided. Includes the
|
|
// JBD2 superblock and zeroed journal data blocks. self.size is expanded by the journal
|
|
// size so that minDiskSize represents usable capacity rather than total image size.
|
|
// - Inode table: Contains information about each file and directory in the filesystem.
|
|
// - Block bitmap: Tracks the allocation status of each block in the filesystem.
|
|
// - Inode bitmap: Tracks the allocation status of each inode in the filesystem.
|
|
// - Directory tree: Represents the hierarchical structure of directories and files.
|
|
// - Group descriptors: Stores metadata about each block group in the filesystem.
|
|
// - Superblock: Contains essential information about the filesystem's configuration.
|
|
//
|
|
// The function performs any necessary final steps to ensure the integrity and consistency
|
|
// of the ext4 filesystem before it can be mounted and used.
|
|
public func close() throws {
|
|
var breadthWiseChildTree: [(parent: Ptr<FileTree.FileTreeNode>?, child: Ptr<FileTree.FileTreeNode>)] = [
|
|
(nil, self.tree.root)
|
|
]
|
|
while !breadthWiseChildTree.isEmpty {
|
|
let (parent, child) = breadthWiseChildTree.removeFirst()
|
|
try self.commit(parent, child) // commit directories iteratively
|
|
if child.pointee.link != nil {
|
|
continue
|
|
}
|
|
breadthWiseChildTree.append(contentsOf: child.pointee.children.map { (child, $0) })
|
|
}
|
|
|
|
// Generate UUID once; shared by filesystem superblock and JBD2 superblock.
|
|
let filesystemUUID = UUID().uuid
|
|
|
|
// Journal init MUST precede optimizeBlockGroupLayout() and commitInodeTable().
|
|
// Reason 1: optimizeBlockGroupLayout reads self.currentBlock — journal blocks
|
|
// must already be written to be counted in the layout calculation.
|
|
// Reason 2: commitInodeTable writes inode 8 to disk — setupJournalInode must
|
|
// have updated self.inodes[7] in memory first.
|
|
var journalByteCount: UInt64 = 0
|
|
if let config = journalConfig {
|
|
// initializeJournal returns the number of blocks written for the journal.
|
|
// journalByteCount is fed into the newSize floor below so that minDiskSize
|
|
// represents usable capacity: the journal is additive overhead on top of
|
|
// the content area. self.size is left unmodified here so the existing
|
|
// lseek + write file-extension path handles the physical resize.
|
|
let journalBlocks = try initializeJournal(config: config, filesystemUUID: filesystemUUID)
|
|
journalByteCount = UInt64(journalBlocks) * self.blockSize
|
|
}
|
|
|
|
let blockGroupSize = optimizeBlockGroupLayout(blocks: self.currentBlock, inodes: UInt32(self.inodes.count))
|
|
let inodeTableOffset = try self.commitInodeTable(
|
|
blockGroups: blockGroupSize.blockGroups,
|
|
inodesPerGroup: blockGroupSize.inodesPerGroup
|
|
)
|
|
if self.pos % self.blockSize != 0 {
|
|
try self.seek(block: self.currentBlock + 1)
|
|
}
|
|
// write bitmaps and group descriptors
|
|
|
|
let bitmapOffset = self.currentBlock
|
|
let bitmapBlocks: UInt32 = blockGroupSize.blockGroups * 2 // each group has two bitmaps - for inodes, and for blocks
|
|
let dataBlocks: UInt32 = bitmapOffset + bitmapBlocks // last data block
|
|
var diskBlocks = dataBlocks
|
|
var contentRequiredBlocks = (blockGroupSize.blockGroups - 1) * self.blocksPerGroup + 1
|
|
if blockGroupSize.blockGroups == 1 {
|
|
contentRequiredBlocks = self.blocksPerGroup // at least 1 block group
|
|
}
|
|
if diskBlocks < contentRequiredBlocks { // for data + metadata
|
|
diskBlocks = contentRequiredBlocks
|
|
}
|
|
let contentRequiredSize = UInt64(contentRequiredBlocks) * self.blockSize
|
|
// minDiskSize is usable capacity; the journal is additive on top.
|
|
var newSize = self.size + journalByteCount
|
|
if newSize < contentRequiredSize {
|
|
newSize = contentRequiredSize
|
|
}
|
|
// number of blocks needed for group descriptors
|
|
let groupDescriptorBlockCount: UInt32 = (blockGroupSize.blockGroups - 1) / self.groupsPerDescriptorBlock + 1
|
|
guard groupDescriptorBlockCount <= self.groupDescriptorBlocks else {
|
|
throw Error.insufficientSpaceForGroupDescriptorBlocks
|
|
}
|
|
|
|
var totalBlocks: UInt32 = 0
|
|
var totalInodes: UInt32 = 0
|
|
let inodeTableSizePerGroup: UInt32 = blockGroupSize.inodesPerGroup * EXT4.InodeSize / self.blockSize
|
|
var groupDescriptors: [GroupDescriptor] = []
|
|
|
|
let minGroups = (((self.pos / UInt64(self.blockSize)) - 1) / UInt64(self.blocksPerGroup)) + 1
|
|
if newSize < minGroups * blocksPerGroup * blockSize {
|
|
newSize = UInt64(minGroups * blocksPerGroup * blockSize)
|
|
}
|
|
let totalGroups = (((newSize / UInt64(self.blockSize)) - 1) / UInt64(self.blocksPerGroup)) + 1
|
|
|
|
// If the provided disk size is not aligned to a blockgroup boundary, it needs to
|
|
// be expanded to the next blockgroup boundary.
|
|
// Example:
|
|
// Provided disk size: 2 GB + 100MB: 2148 MB
|
|
// BlockSize: 4096
|
|
// Blockgroup size: 32768 blocks: 128MB
|
|
// Number of blocks: 549888
|
|
// Number of blockgroups = 549888 / 32768 = 16.78125
|
|
// Aligned disk size = 557056 blocks = 17 blockgroups: 2176 MB
|
|
if newSize < totalGroups * blocksPerGroup * blockSize {
|
|
newSize = UInt64(totalGroups * blocksPerGroup * blockSize)
|
|
}
|
|
// Snapshot groupDescriptorBlocks before self.size potentially changes: the bitmap
|
|
// loop uses this to identify which GDT slots were physically reserved at init time,
|
|
// so it can mark any unused slots as free without accidentally freeing content blocks
|
|
// written starting at reservedDescriptorBlocks + 1.
|
|
let reservedDescriptorBlocks = self.groupDescriptorBlocks
|
|
if self.size < newSize {
|
|
guard newSize / UInt64(self.blockSize) <= UInt64(UInt32.max) else {
|
|
throw Error.cannotResizeFS(newSize)
|
|
}
|
|
self.size = newSize
|
|
let pos = self.pos
|
|
guard lseek(self.handle.fileDescriptor, off_t(self.size - 1), 0) == self.size - 1 else {
|
|
throw Error.cannotResizeFS(self.size)
|
|
}
|
|
let zero: [UInt8] = [0]
|
|
try self.handle.write(contentsOf: zero)
|
|
try self.handle.seek(toOffset: pos)
|
|
}
|
|
for group in 0..<blockGroupSize.blockGroups {
|
|
// keep track of directories, inodes and block per blockgroup
|
|
var dirs: UInt32 = 0
|
|
var inodes: UInt32 = 0
|
|
var blocks: UInt32 = 0
|
|
// blocks bitmap
|
|
var bitmap: [UInt8] = .init(repeating: 0, count: self.blockSize * 2) // 1 for blocks, 1 for inodes
|
|
if (group + 1) * UInt32(self.blocksPerGroup) <= dataBlocks { // fully allocated group
|
|
for i in 0..<(self.blockSize) {
|
|
bitmap[Int(i)] = 0xff // mark as allocated
|
|
}
|
|
blocks = UInt32(self.blocksPerGroup)
|
|
} else if group * UInt32(self.blocksPerGroup) < dataBlocks { // partially allocated group
|
|
for i in 0..<dataBlocks - group * UInt32(self.blocksPerGroup) {
|
|
bitmap[Int(i / 8)] |= 1 << (i % 8)
|
|
blocks += 1
|
|
}
|
|
}
|
|
|
|
if group == 0 { // unused group descriptor blocks
|
|
// blocks used by group descriptors
|
|
|
|
let usedGroupDescriptorBlocks = (totalGroups - 1) / self.groupsPerDescriptorBlock + 1
|
|
for i in 0...usedGroupDescriptorBlocks {
|
|
bitmap[Int(i / 8)] |= 1 << (i % 8)
|
|
}
|
|
if usedGroupDescriptorBlocks + 1 <= reservedDescriptorBlocks {
|
|
for i in usedGroupDescriptorBlocks + 1...reservedDescriptorBlocks {
|
|
bitmap[Int(i / 8)] &= ~(1 << (i % 8))
|
|
blocks -= 1
|
|
}
|
|
}
|
|
}
|
|
|
|
// last blockGroup if not aligned with total size should be marked as allocated
|
|
let remainingBlocks = diskBlocks % self.blocksPerGroup
|
|
if group == totalGroups - 1 && remainingBlocks != 0 && self.size / self.blockSize < self.blocksPerGroup {
|
|
for i in remainingBlocks..<self.blocksPerGroup {
|
|
bitmap[Int(i / 8)] |= 1 << (i % 8)
|
|
}
|
|
if remainingBlocks < self.size / self.blockSize {
|
|
for i in remainingBlocks..<self.size / self.blockSize {
|
|
bitmap[Int(i / 8)] &= ~(1 << (i % 8))
|
|
}
|
|
}
|
|
}
|
|
|
|
// mark deleted blocks as free
|
|
for block in self.deletedBlocks {
|
|
for i in block.start..<block.end where i / self.blocksPerGroup == group {
|
|
let j = i % self.blocksPerGroup
|
|
blocks -= UInt32((bitmap[Int(j / 8)] >> (j % 8)) & 1)
|
|
bitmap[Int(j / 8)] &= ~(1 << (j % 8))
|
|
}
|
|
}
|
|
|
|
// inodes bitmap goes into second bitmap block
|
|
for i in 0..<blockGroupSize.inodesPerGroup {
|
|
let ino = InodeNumber(1 + group * blockGroupSize.inodesPerGroup + i)
|
|
if ino > self.inodes.count {
|
|
continue
|
|
}
|
|
let inode = self.inodes[Int(ino) - 1]
|
|
if ino > 10 && inode.pointee.linksCount == 0 { // deleted files
|
|
continue
|
|
}
|
|
bitmap[Int(self.blockSize) + Int(i / 8)] |= 1 << (i % 8)
|
|
inodes += 1
|
|
if inode.pointee.mode.isDir() {
|
|
dirs += 1
|
|
}
|
|
}
|
|
|
|
for i in (blockGroupSize.inodesPerGroup / 8)..<self.blockSize {
|
|
bitmap[Int(self.blockSize) + Int(i)] = 0xff // mark rest of inodes as occupied
|
|
}
|
|
|
|
// write bitmap
|
|
try bitmap.withUnsafeBytes { bitmapBytes in
|
|
try withUnsafeLittleEndianBuffer(of: bitmapBytes) { b in
|
|
try self.handle.write(contentsOf: b)
|
|
}
|
|
}
|
|
|
|
let blockBitmap = UInt64(bitmapOffset + 2 * group)
|
|
let inodeBitmap = UInt64(bitmapOffset + 2 * group + 1)
|
|
let inodeTable = inodeTableOffset + UInt64(group * inodeTableSizePerGroup)
|
|
let freeBlocksCount = UInt32(self.blocksPerGroup - blocks)
|
|
let freeInodesCount = UInt32(blockGroupSize.inodesPerGroup - inodes)
|
|
groupDescriptors.append(
|
|
// low bits
|
|
GroupDescriptor(
|
|
blockBitmapLow: blockBitmap.lo, // address of block bitmap
|
|
inodeBitmapLow: inodeBitmap.lo, // address of inode bitmap
|
|
inodeTableLow: inodeTable.lo, // address of inode table for this group
|
|
freeBlocksCountLow: freeBlocksCount.lo,
|
|
freeInodesCountLow: freeInodesCount.lo,
|
|
usedDirsCountLow: dirs.lo,
|
|
flags: 0x0000,
|
|
excludeBitmapLow: 0x0000_0000,
|
|
blockBitmapCsumLow: 0x0000,
|
|
inodeBitmapCsumLow: 0x0000,
|
|
itableUnusedLow: 0x0000,
|
|
checksum: 0x0000
|
|
))
|
|
totalBlocks += UInt32(blocks)
|
|
totalInodes += UInt32(inodes)
|
|
}
|
|
|
|
// Since the bitmaps for unoccupied block groups are the same, there is no need
|
|
// to allocate separate memory or storage for each individual bitmap.
|
|
var blockBitmap: [UInt8] = .init(repeating: 0, count: Int(self.blocksPerGroup) / 8)
|
|
var inodeBitmap: [UInt8] = .init(repeating: 0xff, count: Int(self.blocksPerGroup) / 8)
|
|
for i in 0..<inodeTableSizePerGroup + 2 {
|
|
blockBitmap[Int(i) / 8] |= 1 << (i % 8)
|
|
}
|
|
for i in 0..<UInt16(blockGroupSize.inodesPerGroup) {
|
|
inodeBitmap[Int(i) / 8] &= ~(1 << (i % 8))
|
|
}
|
|
for group in blockGroupSize.blockGroups..<totalGroups.lo {
|
|
let blocksInGroup = UInt32(self.blocksPerGroup)
|
|
let blockBitmapOffset = UInt64(group * self.blocksPerGroup + inodeTableSizePerGroup)
|
|
let inodeBitmapOffset = UInt64(group * self.blocksPerGroup + inodeTableSizePerGroup + 1)
|
|
let inodeTableOffset = UInt64(self.blocksPerGroup) * group
|
|
let freeBlocksCount = UInt32(blocksInGroup - inodeTableSizePerGroup - 2)
|
|
let freeInodesCount = UInt32(blockGroupSize.inodesPerGroup)
|
|
groupDescriptors.append(
|
|
// low bits
|
|
GroupDescriptor(
|
|
blockBitmapLow: blockBitmapOffset.lo, // address of block bitmap
|
|
inodeBitmapLow: inodeBitmapOffset.lo, // address of inode bitmap
|
|
inodeTableLow: inodeTableOffset.lo, // address of inode table for this group
|
|
freeBlocksCountLow: freeBlocksCount.lo,
|
|
freeInodesCountLow: freeInodesCount.lo,
|
|
usedDirsCountLow: 0,
|
|
flags: 0x0000,
|
|
excludeBitmapLow: 0x0000_0000,
|
|
blockBitmapCsumLow: 0x0000,
|
|
inodeBitmapCsumLow: 0x0000,
|
|
itableUnusedLow: 0x0000,
|
|
checksum: 0x0000
|
|
))
|
|
totalBlocks += (inodeTableSizePerGroup + 2)
|
|
try self.seek(block: group * self.blocksPerGroup + inodeTableSizePerGroup)
|
|
try self.handle.write(contentsOf: blockBitmap)
|
|
try self.handle.write(contentsOf: inodeBitmap)
|
|
}
|
|
|
|
try self.seek(block: 1)
|
|
|
|
for groupDescriptor in groupDescriptors {
|
|
try withUnsafeLittleEndianBytes(of: groupDescriptor) { bytes in
|
|
try self.handle.write(contentsOf: bytes)
|
|
}
|
|
}
|
|
// write superblock
|
|
try self.seek(block: 0)
|
|
try self.handle.write(contentsOf: Array<UInt8>.init(repeating: 0, count: 1024))
|
|
|
|
let computedInodes = totalGroups * blockGroupSize.inodesPerGroup
|
|
var blocksCount = totalGroups * self.blocksPerGroup
|
|
while blocksCount < totalBlocks {
|
|
blocksCount = UInt64(totalBlocks)
|
|
}
|
|
let totalFreeBlocks: UInt64
|
|
if totalBlocks > blocksCount {
|
|
totalFreeBlocks = 0
|
|
} else {
|
|
totalFreeBlocks = blocksCount - totalBlocks
|
|
}
|
|
var superblock = SuperBlock()
|
|
superblock.inodesCount = computedInodes.lo
|
|
superblock.blocksCountLow = blocksCount.lo
|
|
superblock.blocksCountHigh = blocksCount.hi
|
|
superblock.freeBlocksCountLow = totalFreeBlocks.lo
|
|
superblock.freeBlocksCountHigh = totalFreeBlocks.hi
|
|
let freeInodesCount = computedInodes.lo - totalInodes
|
|
superblock.freeInodesCount = freeInodesCount
|
|
superblock.firstDataBlock = 0
|
|
superblock.logBlockSize = logBlockSize
|
|
superblock.logClusterSize = logBlockSize
|
|
superblock.blocksPerGroup = self.blocksPerGroup
|
|
superblock.clustersPerGroup = self.blocksPerGroup
|
|
superblock.inodesPerGroup = blockGroupSize.inodesPerGroup
|
|
superblock.magic = EXT4.SuperBlockMagic
|
|
superblock.state = 1 // cleanly unmounted
|
|
superblock.errors = 1 // continue on error
|
|
superblock.creatorOS = 3 // freeBSD
|
|
superblock.revisionLevel = 1 // dynamic inode sizes
|
|
superblock.firstInode = EXT4.FirstInode
|
|
superblock.lpfInode = EXT4.LostAndFoundInode
|
|
superblock.inodeSize = UInt16(EXT4.InodeSize)
|
|
superblock.featureIncompat =
|
|
IncompatFeature.filetype | IncompatFeature.extents | IncompatFeature.flexBg
|
|
superblock.featureRoCompat =
|
|
RoCompatFeature.largeFile | RoCompatFeature.hugeFile | RoCompatFeature.extraIsize
|
|
superblock.minExtraIsize = EXT4.ExtraIsize
|
|
superblock.wantExtraIsize = EXT4.ExtraIsize
|
|
superblock.logGroupsPerFlex = 31
|
|
superblock.uuid = filesystemUUID
|
|
var compatFeatures: UInt32 = CompatFeature.sparseSuper2 | CompatFeature.extAttr
|
|
if let config = journalConfig {
|
|
compatFeatures |= CompatFeature.hasJournal.rawValue
|
|
superblock.journalInum = EXT4.JournalInode
|
|
superblock.journalUUID = filesystemUUID
|
|
superblock.journalBlocks = journalInodeBlockBackup()
|
|
superblock.journalBackupType = 1 // s_jnl_backup_type: 1 = s_jnl_blocks[] holds a valid inode backup
|
|
if let mode = config.defaultMode {
|
|
switch mode {
|
|
case .writeback: superblock.defaultMountOpts = DefaultMountOpts.journalWriteback
|
|
case .ordered: superblock.defaultMountOpts = DefaultMountOpts.journalOrdered
|
|
case .journal: superblock.defaultMountOpts = DefaultMountOpts.journalData
|
|
}
|
|
}
|
|
}
|
|
superblock.featureCompat = compatFeatures
|
|
|
|
// Fields intentionally left at zero:
|
|
// s_r_blocks_count_lo: no blocks reserved for root
|
|
// s_mtime / s_wtime: never mounted/written; kernel updates on first access
|
|
// s_mnt_count / s_max_mnt_count: no forced-fsck-after-N-mounts policy
|
|
// s_lastcheck / s_checkinterval: no time-based fsck scheduling
|
|
// s_def_resuid / s_def_resgid: reserved blocks owned by uid/gid 0 (root)
|
|
// s_block_group_nr: this superblock resides in group 0
|
|
// s_volume_name: no volume label
|
|
// s_last_mounted: no recorded prior mount path
|
|
// s_algorithm_usage_bitmap: obsolete compression field, not used
|
|
// s_prealloc_blocks / s_prealloc_dir_blocks: block preallocation not enabled
|
|
// s_reserved_gdt_blocks: online resize not supported
|
|
// s_journal_dev: journal is internal (inode 8), not on an external device
|
|
// s_last_orphan: fresh filesystem, no pending orphan cleanup
|
|
// s_hash_seed / s_def_hash_version: kernel initialises htree hash seed at first mount
|
|
// s_first_meta_bg: meta block group feature not enabled
|
|
// s_mkfs_time: creation timestamp not recorded
|
|
// s_raid_stride / s_mmp_interval / s_mmp_block / s_raid_stripe_width: no RAID or MMP
|
|
// s_checksum_type / s_checksum_seed: metadata checksums not enabled (no csum feature bit)
|
|
// s_snapshot_*: snapshot feature not enabled
|
|
// s_error_count / s_first_error_* / s_last_error_*: fresh filesystem, no recorded errors
|
|
// s_usr_quota_inum / s_grp_quota_inum / s_prj_quota_inum: quotas not enabled
|
|
// s_overhead_clusters: kernel computes dynamically; zero is always safe
|
|
// s_backup_bgs: sparse_super2 active but no secondary backup groups requested
|
|
// s_encrypt_algos / s_encrypt_pw_salt: encryption not enabled
|
|
// s_checksum: superblock checksum not enabled (no metadata_csum feature bit)
|
|
|
|
try withUnsafeLittleEndianBytes(of: superblock) { bytes in
|
|
try self.handle.write(contentsOf: bytes)
|
|
}
|
|
try self.handle.write(contentsOf: Array<UInt8>.init(repeating: 0, count: 2048))
|
|
}
|
|
|
|
// MARK: Private and internal methods and properties
|
|
private var tree: FileTree
|
|
private var deletedBlocks: [(start: UInt32, end: UInt32)] = []
|
|
|
|
// internally accessed by journal setup
|
|
var handle: FileHandle
|
|
var inodes: [Ptr<Inode>]
|
|
let journalConfig: JournalConfig?
|
|
|
|
var pos: UInt64 {
|
|
guard let offset = try? self.handle.offset() else {
|
|
return 0
|
|
}
|
|
return offset
|
|
}
|
|
|
|
var currentBlock: UInt32 {
|
|
self.pos / self.blockSize
|
|
}
|
|
|
|
func seek(block: UInt32) throws {
|
|
try self.handle.seek(toOffset: UInt64(block) * blockSize)
|
|
}
|
|
|
|
private func commitInodeTable(blockGroups: UInt32, inodesPerGroup: UInt32) throws -> UInt64 {
|
|
// inodeTable must go into a new block
|
|
if self.pos % blockSize != 0 {
|
|
try seek(block: currentBlock + 1)
|
|
}
|
|
let inodeTableOffset = UInt64(currentBlock)
|
|
|
|
let inodeSize = MemoryLayout<Inode>.size
|
|
// Write InodeTable
|
|
for inode in self.inodes {
|
|
try withUnsafeLittleEndianBytes(of: inode.pointee) { bytes in
|
|
try handle.write(contentsOf: bytes)
|
|
}
|
|
try self.handle.write(
|
|
contentsOf: Array<UInt8>.init(repeating: 0, count: Int(EXT4.InodeSize) - inodeSize))
|
|
}
|
|
let tableSize: UInt64 = UInt64(EXT4.InodeSize) * blockGroups * inodesPerGroup
|
|
let rest = tableSize - UInt64(self.inodes.count) * EXT4.InodeSize
|
|
let zeroBlock = Array<UInt8>.init(repeating: 0, count: Int(self.blockSize))
|
|
for _ in 0..<(rest / self.blockSize) {
|
|
try self.handle.write(contentsOf: zeroBlock)
|
|
}
|
|
try self.handle.write(contentsOf: Array<UInt8>.init(repeating: 0, count: Int(rest % self.blockSize)))
|
|
return inodeTableOffset
|
|
}
|
|
|
|
// optimizes the distribution of blockGroups to obtain the lowest number of blockGroups needed to
|
|
// represent all the inodes and all the blocks in the FS
|
|
private func optimizeBlockGroupLayout(blocks: UInt32, inodes: UInt32) -> (
|
|
blockGroups: UInt32, inodesPerGroup: UInt32
|
|
) {
|
|
// counts the number of blockGroups given a particular inodesPerGroup size
|
|
let groupCount: (_ blocks: UInt32, _ inodes: UInt32, _ inodesPerGroup: UInt32) -> UInt32 = {
|
|
blocks, inodes, inodesPerGroup in
|
|
let inodeBlocksPerGroup: UInt32 = inodesPerGroup * EXT4.InodeSize / self.blockSize
|
|
let dataBlocksPerGroup: UInt32 = self.blocksPerGroup - inodeBlocksPerGroup - 2 // save room for the bitmaps
|
|
// Increase the block count to ensure there are enough groups for all the inodes.
|
|
let minBlocks: UInt32 = (inodes - 1) / inodesPerGroup * dataBlocksPerGroup + 1
|
|
var updatedBlocks = blocks
|
|
if blocks < minBlocks {
|
|
updatedBlocks = minBlocks
|
|
}
|
|
return (updatedBlocks + dataBlocksPerGroup - 1) / dataBlocksPerGroup
|
|
}
|
|
|
|
var groups: UInt32 = UInt32.max
|
|
var inodesPerGroup: UInt32 = 0
|
|
let inc = Int(self.blockSize * 512) / Int(EXT4.InodeSize) // inodesPerGroup
|
|
// minimizes the number of blockGroups needed to its lowest value
|
|
for ipg in stride(from: inc, through: Int(self.maxInodesPerGroup), by: inc) {
|
|
let g = groupCount(blocks, inodes, UInt32(ipg))
|
|
if g < groups {
|
|
groups = g
|
|
inodesPerGroup = UInt32(ipg)
|
|
}
|
|
}
|
|
return (groups, inodesPerGroup)
|
|
}
|
|
|
|
private func commit(_ parentPtr: Ptr<FileTree.FileTreeNode>?, _ nodePtr: Ptr<FileTree.FileTreeNode>) throws {
|
|
let node = nodePtr.pointee
|
|
let inodePtr = self.inodes[Int(node.inode) - 1]
|
|
var inode = inodePtr.pointee
|
|
guard inode.linksCount > 0 else {
|
|
return
|
|
}
|
|
if node.link != nil {
|
|
return
|
|
}
|
|
if self.pos % self.blockSize != 0 {
|
|
try self.seek(block: self.currentBlock + 1)
|
|
}
|
|
if inode.mode.isDir() {
|
|
let startBlock = self.currentBlock
|
|
var left: Int = Int(self.blockSize)
|
|
try writeDirEntry(name: ".", inode: node.inode, left: &left)
|
|
if let parent = parentPtr {
|
|
try writeDirEntry(name: "..", inode: parent.pointee.inode, left: &left)
|
|
} else {
|
|
try writeDirEntry(name: "..", inode: node.inode, left: &left)
|
|
}
|
|
var sortedChildren = Array(node.children)
|
|
sortedChildren.sort { left, right in
|
|
left.pointee.inode < right.pointee.inode
|
|
}
|
|
for childPtr in sortedChildren {
|
|
let child = childPtr.pointee
|
|
try writeDirEntry(name: child.name, inode: child.inode, left: &left, link: child.link)
|
|
}
|
|
try finishDirEntryBlock(&left)
|
|
let endBlock = self.currentBlock
|
|
let size: UInt64 = UInt64(endBlock - startBlock) * self.blockSize
|
|
inode.sizeLow = size.lo
|
|
inode.sizeHigh = size.hi
|
|
inodePtr.pointee = inode
|
|
node.blocks = (startBlock, endBlock)
|
|
nodePtr.pointee = node
|
|
if self.pos % self.blockSize != 0 {
|
|
try self.seek(block: self.currentBlock + 1)
|
|
}
|
|
inode = try self.writeExtents(inode, (startBlock, endBlock))
|
|
inodePtr.pointee = inode
|
|
}
|
|
}
|
|
|
|
private func fillExtents(
|
|
node: inout ExtentLeafNode, numExtents: UInt32, numBlocks: UInt32, start: UInt32, offset: UInt32
|
|
) {
|
|
for i in 0..<numExtents {
|
|
let extentBlock: UInt32 = offset + i * EXT4.MaxBlocksPerExtent
|
|
var length = numBlocks - extentBlock
|
|
if length > EXT4.MaxBlocksPerExtent {
|
|
length = EXT4.MaxBlocksPerExtent
|
|
}
|
|
let extentStart: UInt32 = start + extentBlock
|
|
let extent = ExtentLeaf(
|
|
block: extentBlock,
|
|
length: UInt16(length),
|
|
startHigh: 0,
|
|
startLow: extentStart
|
|
)
|
|
node.leaves.append(extent)
|
|
}
|
|
}
|
|
|
|
func writeExtents(_ inode: Inode, _ blocks: (start: UInt32, end: UInt32)) throws -> Inode {
|
|
var inode = inode
|
|
// rest of code assumes that extents MUST go into a new block
|
|
if self.pos % self.blockSize != 0 {
|
|
try self.seek(block: self.currentBlock + 1)
|
|
}
|
|
let dataBlocks = blocks.end - blocks.start
|
|
let numExtents = (dataBlocks + EXT4.MaxBlocksPerExtent - 1) / EXT4.MaxBlocksPerExtent
|
|
var usedBlocks = dataBlocks
|
|
let extentNodeSize = 12
|
|
let extentsPerBlock = self.blockSize / extentNodeSize - 1
|
|
var blockData: [UInt8] = .init(repeating: 0, count: 60)
|
|
var blockIndex: Int = 0
|
|
switch numExtents {
|
|
case 0:
|
|
return inode // noop
|
|
case 1..<5:
|
|
let extentHeader = ExtentHeader(
|
|
magic: EXT4.ExtentHeaderMagic,
|
|
entries: UInt16(numExtents),
|
|
max: 4,
|
|
depth: 0,
|
|
generation: 0)
|
|
|
|
var node = ExtentLeafNode(header: extentHeader, leaves: [])
|
|
fillExtents(node: &node, numExtents: numExtents, numBlocks: dataBlocks, start: blocks.start, offset: 0)
|
|
withUnsafeLittleEndianBytes(of: node.header) { bytes in
|
|
for b in bytes {
|
|
blockData[blockIndex] = b
|
|
blockIndex = blockIndex + 1
|
|
}
|
|
}
|
|
for leaf in node.leaves {
|
|
withUnsafeLittleEndianBytes(of: leaf) { bytes in
|
|
for b in bytes {
|
|
blockData[blockIndex] = b
|
|
blockIndex = blockIndex + 1
|
|
}
|
|
}
|
|
}
|
|
case 5..<4 * UInt32(extentsPerBlock) + 1:
|
|
let extentBlocks = (numExtents + extentsPerBlock - 1) / extentsPerBlock
|
|
usedBlocks += extentBlocks
|
|
let extentHeader = ExtentHeader(
|
|
magic: EXT4.ExtentHeaderMagic,
|
|
entries: UInt16(extentBlocks),
|
|
max: 4,
|
|
depth: 1,
|
|
generation: 0
|
|
)
|
|
var root = ExtentIndexNode(header: extentHeader, indices: [])
|
|
for i in 0..<extentBlocks {
|
|
if self.pos % self.blockSize != 0 {
|
|
try self.seek(block: self.currentBlock + 1)
|
|
}
|
|
let extentIdx = ExtentIndex(
|
|
block: i * extentsPerBlock * EXT4.MaxBlocksPerExtent,
|
|
leafLow: self.currentBlock,
|
|
leafHigh: 0,
|
|
unused: 0)
|
|
var extentsInBlock = numExtents - i * extentsPerBlock
|
|
if extentsInBlock > extentsPerBlock {
|
|
extentsInBlock = extentsPerBlock
|
|
}
|
|
let leafHeader = ExtentHeader(
|
|
magic: EXT4.ExtentHeaderMagic,
|
|
entries: UInt16(extentsInBlock),
|
|
max: UInt16(extentsPerBlock),
|
|
depth: 0,
|
|
generation: 0
|
|
)
|
|
var leafNode = ExtentLeafNode(header: leafHeader, leaves: [])
|
|
let offset = i * extentsPerBlock * EXT4.MaxBlocksPerExtent
|
|
fillExtents(
|
|
node: &leafNode, numExtents: extentsInBlock, numBlocks: dataBlocks,
|
|
start: blocks.start,
|
|
offset: offset)
|
|
try withUnsafeLittleEndianBytes(of: leafNode.header) { bytes in
|
|
try self.handle.write(contentsOf: bytes)
|
|
}
|
|
for leaf in leafNode.leaves {
|
|
try withUnsafeLittleEndianBytes(of: leaf) { bytes in
|
|
try self.handle.write(contentsOf: bytes)
|
|
}
|
|
}
|
|
let extentTail = ExtentTail(checksum: leafNode.leaves.last!.block)
|
|
try withUnsafeLittleEndianBytes(of: extentTail) { bytes in
|
|
try self.handle.write(contentsOf: bytes)
|
|
}
|
|
root.indices.append(extentIdx)
|
|
}
|
|
withUnsafeLittleEndianBytes(of: root.header) { bytes in
|
|
for b in bytes {
|
|
blockData[blockIndex] = b
|
|
blockIndex = blockIndex + 1
|
|
}
|
|
}
|
|
for leaf in root.indices {
|
|
withUnsafeLittleEndianBytes(of: leaf) { bytes in
|
|
for b in bytes {
|
|
blockData[blockIndex] = b
|
|
blockIndex = blockIndex + 1
|
|
}
|
|
}
|
|
}
|
|
default:
|
|
throw Error.fileTooBig(UInt64(dataBlocks) * self.blockSize)
|
|
}
|
|
inode.block = (
|
|
blockData[0], blockData[1], blockData[2], blockData[3], blockData[4], blockData[5], blockData[6],
|
|
blockData[7],
|
|
blockData[8], blockData[9],
|
|
blockData[10], blockData[11], blockData[12], blockData[13], blockData[14], blockData[15], blockData[16],
|
|
blockData[17], blockData[18], blockData[19],
|
|
blockData[20], blockData[21], blockData[22], blockData[23], blockData[24], blockData[25], blockData[26],
|
|
blockData[27], blockData[28], blockData[29],
|
|
blockData[30], blockData[31], blockData[32], blockData[33], blockData[34], blockData[35], blockData[36],
|
|
blockData[37], blockData[38], blockData[39],
|
|
blockData[40], blockData[41], blockData[42], blockData[43], blockData[44], blockData[45], blockData[46],
|
|
blockData[47], blockData[48], blockData[49],
|
|
blockData[50], blockData[51], blockData[52], blockData[53], blockData[54], blockData[55], blockData[56],
|
|
blockData[57], blockData[58], blockData[59]
|
|
)
|
|
// ensure that inode's block count includes extent blocks
|
|
inode.blocksLow += usedBlocks
|
|
inode.flags = InodeFlag.extents | inode.flags
|
|
return inode
|
|
}
|
|
|
|
// writes a single directory entry
|
|
private func writeDirEntry(name: String, inode: InodeNumber, left: inout Int, link: InodeNumber? = nil) throws {
|
|
guard self.inodes[Int(inode) - 1].pointee.linksCount > 0 else {
|
|
return
|
|
}
|
|
guard let nameData = name.data(using: .utf8) else {
|
|
throw Error.invalidName(name)
|
|
}
|
|
let directoryEntrySize = MemoryLayout<DirectoryEntry>.size
|
|
let rlb = directoryEntrySize + nameData.count
|
|
let rl = (rlb + 3) & ~3
|
|
if left < rl + 12 {
|
|
try self.finishDirEntryBlock(&left)
|
|
}
|
|
var mode = self.inodes[Int(inode) - 1].pointee.mode
|
|
var inodeNum = inode
|
|
if let link {
|
|
mode = self.inodes[Int(link) - 1].pointee.mode | 0o777
|
|
inodeNum = link
|
|
}
|
|
let entry = DirectoryEntry(
|
|
inode: inodeNum,
|
|
recordLength: UInt16(rl),
|
|
nameLength: UInt8(nameData.count),
|
|
fileType: mode.fileType()
|
|
)
|
|
try withUnsafeLittleEndianBytes(of: entry) { bytes in
|
|
try self.handle.write(contentsOf: bytes)
|
|
}
|
|
|
|
try nameData.withUnsafeBytes { buffer in
|
|
try withUnsafeLittleEndianBuffer(of: buffer) { b in
|
|
try self.handle.write(contentsOf: b)
|
|
}
|
|
}
|
|
try self.handle.write(contentsOf: [UInt8](repeating: 0, count: rl - rlb))
|
|
left = left - rl
|
|
}
|
|
|
|
private func finishDirEntryBlock(_ left: inout Int) throws {
|
|
defer { left = Int(self.blockSize) }
|
|
if left <= 0 {
|
|
return
|
|
}
|
|
let entry = DirectoryEntry(
|
|
inode: InodeNumber(0),
|
|
recordLength: UInt16(left),
|
|
nameLength: 0,
|
|
fileType: 0
|
|
)
|
|
try withUnsafeLittleEndianBytes(of: entry) { bytes in
|
|
try self.handle.write(contentsOf: bytes)
|
|
}
|
|
left = left - MemoryLayout<DirectoryEntry>.size
|
|
if left < 4 {
|
|
throw Error.noSpaceForTrailingDEntry
|
|
}
|
|
try self.handle.write(contentsOf: [UInt8](repeating: 0, count: Int(left)))
|
|
}
|
|
|
|
public enum Error: Swift.Error, CustomStringConvertible, Sendable, Equatable {
|
|
case notDirectory(_ path: FilePath)
|
|
case notFile(_ path: FilePath)
|
|
case notFound(_ path: FilePath)
|
|
case alreadyExists(_ path: FilePath)
|
|
case unsupportedFiletype
|
|
case maximumLinksExceeded(_ path: FilePath)
|
|
case fileTooBig(_ size: UInt64)
|
|
case invalidLink(_ path: FilePath)
|
|
case invalidName(_ name: String)
|
|
case noSpaceForTrailingDEntry
|
|
case insufficientSpaceForGroupDescriptorBlocks
|
|
case cannotCreateHardlinksToDirTarget(_ path: FilePath)
|
|
case cannotTruncateFile(_ path: FilePath)
|
|
case cannotCreateSparseFile(_ path: FilePath)
|
|
case cannotResizeFS(_ size: UInt64)
|
|
case invalidBlockSize(_ size: UInt32)
|
|
case journalTooSmall(_ size: UInt64)
|
|
public var description: String {
|
|
switch self {
|
|
case .notDirectory(let path):
|
|
return "\(path) is not a directory"
|
|
case .notFile(let path):
|
|
return "\(path) is not a file"
|
|
case .notFound(let path):
|
|
return "\(path) not found"
|
|
case .alreadyExists(let path):
|
|
return "\(path) already exists"
|
|
case .unsupportedFiletype:
|
|
return "file type not supported"
|
|
case .maximumLinksExceeded(let path):
|
|
return "maximum links exceeded for path: \(path)"
|
|
case .fileTooBig(let size):
|
|
return "\(size) exceeds max file size (128 GiB)"
|
|
case .invalidLink(let path):
|
|
return "'\(path)' is an invalid link"
|
|
case .invalidName(let name):
|
|
return "'\(name)' is an invalid name"
|
|
case .noSpaceForTrailingDEntry:
|
|
return "not enough space for trailing dentry"
|
|
case .insufficientSpaceForGroupDescriptorBlocks:
|
|
return "not enough space for group descriptor blocks"
|
|
case .cannotCreateHardlinksToDirTarget(let path):
|
|
return "cannot create hard links to directory target: \(path)"
|
|
case .cannotTruncateFile(let path):
|
|
return "cannot truncate file: \(path)"
|
|
case .cannotCreateSparseFile(let path):
|
|
return "cannot create sparse file at \(path)"
|
|
case .cannotResizeFS(let size):
|
|
return "cannot set filesystem size to \(size) bytes"
|
|
case .invalidBlockSize(let size):
|
|
return "invalid block size \(size): must be 1024, 2048, or 4096"
|
|
case .journalTooSmall(let size):
|
|
return "requested journal size \(size) bytes is too small; minimum is \(EXT4.MinJournalBlocks) blocks (JBD2_MIN_JOURNAL_BLOCKS)"
|
|
}
|
|
}
|
|
}
|
|
|
|
deinit {
|
|
self.inodes.removeAll()
|
|
}
|
|
}
|
|
}
|
|
|
|
extension Date {
|
|
func fs() -> UInt64 {
|
|
if self == Date.distantPast {
|
|
return 0
|
|
}
|
|
|
|
let s = self.timeIntervalSince1970
|
|
|
|
if s < -0x8000_0000 {
|
|
return 0x8000_0000
|
|
}
|
|
|
|
if s > 0x3_7fff_ffff {
|
|
return 0x3_7fff_ffff
|
|
}
|
|
|
|
// 32 bits - base: seconds since January 1, 1970, signed (negative for pre-1970 dates)
|
|
// 2 bits - epoch: overflow counter (0-3), how many times the 32-bit seconds field has wrapped
|
|
// 30 bits - nanoseconds (0-999,999,999)
|
|
let sInt64 = Int64(floor(s))
|
|
let base = Int32(truncatingIfNeeded: sInt64)
|
|
let epoch = UInt64(sInt64 - Int64(base))
|
|
let nanoseconds = min(UInt32((s - floor(s)) * 1_000_000_000), 999_999_999)
|
|
return UInt64(UInt32(bitPattern: base)) | epoch | (UInt64(nanoseconds) << 34)
|
|
}
|
|
}
|