tart ip: keep waiting for the /var/db/dhcpd_leases file to appear (#254)

I initially wanted a one-second wait but made a human mistake.

Fixes #249

.ci/create-pkg.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+set -e
+
+export VERSION="${CIRRUS_TAG:-0}"
+
+mkdir -p .ci/pkg/
+cp .build/arm64-apple-macosx/debug/tart .ci/pkg/
+pkgbuild --root .ci/pkg --version $VERSION --install-location /usr/local/bin/ --identifier com.github.cirruslabs.tart --sign "Developer ID Installer: Cirrus Labs, Inc. (9M2P8L4D89)" "./dist/Tart-$VERSION.pkg"
+xcrun notarytool submit "./dist/Tart-$VERSION.pkg" --keychain-profile "notarytool" --wait
+xcrun stapler staple "./dist/Tart-$VERSION.pkg"

.cirrus.yml

@@ -22,10 +22,24 @@ task:
   macos_instance:
     image: ghcr.io/cirruslabs/macos-ventura-xcode:latest
   env:
+    MACOS_CERTIFICATE: ENCRYPTED[552b9d275d1c2bdbc1bff778b104a8f9a53cbd0d59344d4b7f6d0ca3c811a5cefb97bef9ba0ef31c219cb07bdacdd2c2]
+    AC_PASSWORD: ENCRYPTED[4a761023e7e06fe2eb350c8b6e8e7ca961af193cb9ba47605f25f1d353abc3142606f412e405be48fd897a78787ea8c2]
     GITHUB_TOKEN: ENCRYPTED[!98ace8259c6024da912c14d5a3c5c6aac186890a8d4819fad78f3e0c41a4e0cd3a2537dd6e91493952fb056fa434be7c!]
     GORELEASER_KEY: ENCRYPTED[!9b80b6ef684ceaf40edd4c7af93014ee156c8aba7e6e5795f41c482729887b5c31f36b651491d790f1f668670888d9fd!]
-  install_script: brew install go goreleaser/tap/goreleaser-pro
+  setup_script:
+    - cd $HOME
+    - echo $MACOS_CERTIFICATE | base64 --decode > certificate.p12
+    - security create-keychain -p password101 build.keychain
+    - security default-keychain -s build.keychain
+    - security unlock-keychain -p password101 build.keychain
+    - security import certificate.p12 -k build.keychain -P password101 -T /usr/bin/codesign -T /usr/bin/pkgbuild
+    - security set-key-partition-list -S apple-tool:,apple:,codesign: -s -k password101 build.keychain
+    - xcrun notarytool store-credentials "notarytool" --apple-id "hello@cirruslabs.org" --team-id "9M2P8L4D89" --password $AC_PASSWORD
+  install_script: 
+    - brew install go goreleaser/tap/goreleaser-pro
+    - brew install mitchellh/gon/gon
   info_script:
+    - security find-identity -v
     - xcodebuild -version
     - swift -version
   release_script: goreleaser

.github/FUNDING.yml

@@ -0,0 +1 @@
+github: [cirruslabs]

.goreleaser.yml

@@ -7,13 +7,16 @@ builds:
     goarch:
       - arm64
     prebuilt:
-      path: .build/{{ .Arch }}-apple-macosx/debug/tart
+      path: .build/arm64-apple-macosx/debug/tart 
+    hooks:
+      post: 
+        - gon gon.hcl
+        - .ci/create-pkg.sh
 
 before:
   hooks:
     - .ci/set-version.sh
     - swift build -c debug --product tart
-    - codesign --sign - --entitlements Resources/tart.entitlements --force .build/arm64-apple-macosx/debug/tart
 
 archives:
   - id: binary
@@ -24,6 +27,8 @@ archives:
 
 release:
   prerelease: auto
+  extra_files:
+    - glob: ./dist/Tart-{{ .Tag }}.pkg
 
 brews:
   - name: tart

README.md

@@ -1,6 +1,6 @@
 ![Tart – open source virtualization for your automation needs](Resources/TartSocial.png)
 
-*Tart* is a virtualization toolset to build, run and manage virtual machines on Apple Silicon.
+*Tart* is a virtualization toolset to build, run and manage macOS and Linux virtual machines on Apple Silicon.
 Built by CI engineers for your automation needs. Here are some highlights of Tart:
 
 * Tart uses Apple's own `Virtualization.Framework` for [near-native performance](https://browser.geekbench.com/v5/cpu/compare/14966395?baseline=14966339).
@@ -8,6 +8,22 @@ Built by CI engineers for your automation needs. Here are some highlights of Tar
 * Use Tart Packer Plugin to automate VM creation.
 * Built-in CI integration.
 
+*Tart* is already adopted by several automation services:
+
+<p align="center">
+  <a href="https://cirrus-ci.org/guide/macOS/" target=_blank>
+    <img src="https://github.com/cirruslabs/tart/raw/main/Resources/Users/CirrusCI.png" height="65"/>
+  </a>
+  <a href="https://codemagic.io/" target=_blank>
+    <img src="https://github.com/cirruslabs/tart/raw/main/Resources/Users/Codemagic.png" height="65"/>
+  </a>
+  <a href="https://testingbot.com/" target=_blank>
+    <img src="https://github.com/cirruslabs/tart/raw/main/Resources/Users/TestingBot.png" height="65"/>
+  </a>
+</p>
+
+## Usage
+
 Try running a Tart VM on your Apple Silicon device running macOS Monterey or later (will download a 25 GB image):
 
 ```shell
@@ -84,6 +100,11 @@ For the example above, `tart` binary will be saved to `$PWD/artifacts/Build/bina
 
 ### Creating from scratch
 
+Tart supports macOS and Linux virtual machines. All commands like `run` and `pull` work the same way regarding of the underlying OS a particular VM image has.
+The only difference is how such VM images are created. Please check sections below for [macOS](#creating-a-macos-vm-image-from-scratch) and [Linux](#creating-a-linux-vm-image-from-scratch) instructions.
+
+#### Creating a macOS VM image from scratch
+
 Tart can create VMs from `*.ipsw` files. You can download a specific `*.ipsw` file [here](https://ipsw.me/) or you can
 use `latest` instead of a path to `*.ipsw` to download the latest available version:
 
@@ -100,6 +121,27 @@ After the initial booting of the VM you'll need to manually go through the macOS
 4. Disable Screen Saver.
 5. Run `sudo visudo` in Terminal, find `%admin ALL=(ALL) ALL` add `admin ALL=(ALL) NOPASSWD: ALL` to allow sudo without a password.
 
+#### Creating a Linux VM image from scratch
+
+```bash
+# Create a bare VM
+tart create --linux ubuntu
+
+# Install Ubuntu
+tart run --disk focal-desktop-arm64.iso ubuntu
+
+# Run VM
+tart run ubuntu
+```
+
+After the initial setup please make sure your VM can be SSH-ed into by running the following commands inside your VM:
+
+```shell
+sudo apt update
+sudo apt install -y openssh-server
+sudo ufw allow ssh
+```
+
 ### Configuring a VM
 
 By default, a tart VM uses 2 CPUs and 4 GB of memory with a `1024x768` display. This can be changed with `tart set` command.
@@ -165,10 +207,20 @@ tart push my-local-vm-name acme.io/remoteorg/name:latest acme.io/remoteorg/name:
 
 #### Pulling a Remote Image
 
+You can either pull an image:
+
 ```shell
-tart pull acme.io/remoteorg/name:latest my-local-vm-name
+tart pull acme.io/remoteorg/name:latest
 ```
 
+...or instantiate a VM from a remote image:
+
+```shell
+tart clone acme.io/remoteorg/name:latest my-local-vm-name
+```
+
+This invocation calls the `tart pull` implicitly (if the image is not being present) before doing the actual cloning.
+
 ## FAQ
 
 <details>
@@ -186,8 +238,8 @@ tart pull acme.io/remoteorg/name:latest my-local-vm-name
 <details>
   <summary>Why Tart is free and open sourced?</summary>
 
-  Tart is a relatively small project, and it didn't feel right to try to monetize it.
-  Apple did all the heavy lifting with their `Virtualization.Framework`.
+  Apple did all the heavy lifting with their `Virtualization.Framework` and it just felt right to develop Tart in the open.
+  Please consider [becoming a sponsor](https://github.com/sponsors/cirruslabs) if you find Tart saving a substantial amount of money on licensing and engineering hours for your company.
 </details>
 
 <details>
@@ -216,3 +268,21 @@ tart pull acme.io/remoteorg/name:latest my-local-vm-name
   Tart is limited by functionality of Apple's `Virtualization.Framework`. At the moment `Virtualization.Framework`
   doesn't support nested virtualization.
 </details>
+
+<details>
+  <summary>Changing the default NAT subnet</summary>
+
+  To change the default network to `192.168.77.1`:
+
+  ```
+  sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.vmnet.plist Shared_Net_Address -string 192.168.77.1
+  ```
+
+  Note that even through a network would normally be specified as `192.168.77.0`, the [vmnet framework](https://developer.apple.com/documentation/vmnet) seems to treat this as a starting address too and refuses to pick up such network-like values.
+
+  The default subnet mask `255.255.255.0` should suffice for most use-cases, however, you can also change it to `255.255.0.0`, for example:
+
+  ```
+  sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.vmnet.plist Shared_Net_Mask -string 255.255.0.0
+  ```
+</details>

Resources/Users/CirrusCI.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:dbcf6f65f26c0e17b2fe55a9712fc783315cd64905a0febce758b31d7e4e923b
+size 6787

Resources/Users/Codemagic.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:4239996f30145992936cfc8faa0232fa8904aedf4de61e30ef4c4fc86cad587f
+size 14588

Resources/Users/TestingBot.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:227192fcd215c9cc05b1ebcd2616bd1f8c95be184726f64d91fc4507a88c66e1
+size 18393

Resources/tart.entitlements

@@ -5,4 +5,4 @@
 	<key>com.apple.security.virtualization</key>
 	<true/>
 </dict>
-</plist>
+</plist>

Sources/tart/Commands/Clone.swift

@@ -32,12 +32,22 @@ struct Clone: AsyncParsableCommand {
       }
 
       let sourceVM = try VMStorageHelper.open(sourceName)
-      let generateMAC = try localStorage.hasVMsWithMACAddress(macAddress: sourceVM.macAddress())
 
       let tmpVMDir = try VMDirectory.temporary()
+
+      // Lock the temporary VM directory to prevent it's garbage collection
+      let tmpVMDirLock = try FileLock(lockURL: tmpVMDir.baseURL)
+      try tmpVMDirLock.lock()
+
       try await withTaskCancellationHandler(operation: {
+        let lock = try FileLock(lockURL: Config().tartHomeDir)
+        try lock.lock()
+
+        let generateMAC = try localStorage.hasVMsWithMACAddress(macAddress: sourceVM.macAddress())
         try sourceVM.clone(to: tmpVMDir, generateMAC: generateMAC)
         try localStorage.move(newName, from: tmpVMDir)
+
+        try lock.unlock()
       }, onCancel: {
         try? FileManager.default.removeItem(at: tmpVMDir.baseURL)
       })

Sources/tart/Commands/Create.swift

@@ -9,26 +9,44 @@ struct Create: AsyncParsableCommand {
   @Argument(help: "VM name")
   var name: String
 
-  @Option(help: ArgumentHelp("Path to the IPSW file (or \"latest\") to fetch the latest appropriate IPSW", valueName: "path")) 
+  @Option(help: ArgumentHelp("create a macOS VM using path to the IPSW file (or \"latest\") to fetch the latest appropriate IPSW", valueName: "path"))
   var fromIPSW: String?
 
+  @Flag(help: "create a Linux VM")
+  var linux: Bool = false
+
   @Option(help: ArgumentHelp("Disk size in Gb")) 
   var diskSize: UInt16 = 50
 
   func validate() throws {
-    if fromIPSW == nil {
-      throw ValidationError("Please specify a --from-ipsw option!")
+    if fromIPSW == nil && !linux {
+      throw ValidationError("Please specify either a --from-ipsw or --linux option!")
     }
   }
 
   func run() async throws {
     do {
       let tmpVMDir = try VMDirectory.temporary()
+
+      // Lock the temporary VM directory to prevent it's garbage collection
+      let tmpVMDirLock = try FileLock(lockURL: tmpVMDir.baseURL)
+      try tmpVMDirLock.lock()
+
       try await withTaskCancellationHandler(operation: {
-        if fromIPSW! == "latest" {
-          _ = try await VM(vmDir: tmpVMDir, ipswURL: nil, diskSizeGB: diskSize)
-        } else {
-          _ = try await VM(vmDir: tmpVMDir, ipswURL: URL(fileURLWithPath: fromIPSW!), diskSizeGB: diskSize)
+        if let fromIPSW = fromIPSW {
+          if fromIPSW == "latest" {
+            _ = try await VM(vmDir: tmpVMDir, ipswURL: nil, diskSizeGB: diskSize)
+          } else {
+            _ = try await VM(vmDir: tmpVMDir, ipswURL: URL(fileURLWithPath: fromIPSW), diskSizeGB: diskSize)
+          }
+        }
+
+        if linux {
+          if #available(macOS 13, *) {
+            _ = try await VM.linux(vmDir: tmpVMDir, diskSizeGB: diskSize)
+          } else {
+            throw UnsupportedOSError("Linux VMs", "are")
+          }
         }
 
         try VMStorageLocal().move(name, from: tmpVMDir)

Sources/tart/Commands/IP.swift

@@ -16,14 +16,21 @@ struct IP: AsyncParsableCommand {
     do {
       let vmDir = try VMStorageLocal().open(name)
       let vmConfig = try VMConfig.init(fromURL: vmDir.configURL)
+      let vmMACAddress = MACAddress(fromString: vmConfig.macAddress.string)!
 
-      guard let ip = try await IP.resolveIP(vmConfig, secondsToWait: wait) else {
+      guard let ipViaDHCP = try await IP.resolveIP(vmMACAddress, secondsToWait: wait) else {
         print("no IP address found, is your VM running?")
 
         Foundation.exit(1)
       }
 
-      print(ip)
+      if let ipViaARP = try ARPCache.ResolveMACAddress(macAddress: vmMACAddress), ipViaARP != ipViaDHCP {
+        fputs("WARNING: DHCP lease and ARP cache entries for MAC address \(vmMACAddress) differ: "
+          + "got \(ipViaDHCP) and \(ipViaARP) respectively, consider reporting this case to"
+          + " https://github.com/cirruslabs/tart/issues/172\n", stderr)
+      }
+
+      print(ipViaDHCP)
 
       Foundation.exit(0)
     } catch {
@@ -33,16 +40,16 @@ struct IP: AsyncParsableCommand {
     }
   }
 
-  static public func resolveIP(_ config: VMConfig, secondsToWait: UInt16) async throws -> IPv4Address? {
+  static public func resolveIP(_ vmMACAddress: MACAddress, secondsToWait: UInt16) async throws -> IPv4Address? {
     let waitUntil = Calendar.current.date(byAdding: .second, value: Int(secondsToWait), to: Date.now)!
-    let vmMacAddress = MACAddress(fromString: config.macAddress.string)!
 
     repeat {
-      if let ip = try Leases().resolveMACAddress(macAddress: vmMacAddress) {
+      if let leases = try Leases(), let ip = try leases.resolveMACAddress(macAddress: vmMACAddress) {
         return ip
       }
 
-      try await Task.sleep(nanoseconds: 1_000_000)
+      // wait a second
+      try await Task.sleep(nanoseconds: 1_000_000_000)
     } while Date.now < waitUntil
 
     return nil

Sources/tart/Commands/Login.swift

@@ -45,7 +45,7 @@ struct Login: AsyncParsableCommand {
 
       do {
         let registry = try Registry(host: host, namespace: "", insecure: insecure,
-          credentialsProvider: credentialsProvider)
+          credentialsProviders: [credentialsProvider])
         try await registry.ping()
       } catch {
         print("invalid credentials: \(error)")

Sources/tart/Commands/Prune.swift

@@ -16,14 +16,21 @@ struct Prune: AsyncParsableCommand {
     valueName: "n"))
   var cacheBudget: UInt?
 
+  @Flag(help: .hidden)
+  var gc: Bool = false
+
   func validate() throws {
-    if olderThan == nil && cacheBudget == nil {
-      throw ValidationError("at least one criteria must be specified")
+    if olderThan == nil && cacheBudget == nil && !gc {
+      throw ValidationError("at least one pruning criteria must be specified")
     }
   }
 
   func run() async throws {
     do {
+      if gc {
+        try VMStorageOCI().gc()
+      }
+
       // Clean up cache entries based on last accessed date
       if let olderThan = olderThan {
         let olderThanInterval = Int(exactly: olderThan)!.days.timeInterval
@@ -94,7 +101,7 @@ struct Prune: AsyncParsableCommand {
         break
       }
 
-      cacheReclaimedBytes -= try prunable.sizeBytes()
+      cacheReclaimedBytes += try prunable.sizeBytes()
       try prunable.delete()
     }
   }

Sources/tart/Commands/Rename.swift

@@ -0,0 +1,40 @@
+import ArgumentParser
+import Foundation
+
+struct Rename: AsyncParsableCommand {
+    static var configuration = CommandConfiguration(abstract: "Rename a VM")
+
+    @Argument(help: "VM name")
+    var name: String
+
+    @Argument(help: "new VM name")
+    var newName: String
+
+    func validate() throws {
+        if newName.contains("/") {
+            throw ValidationError("<new-name> should be a local name")
+        }
+    }
+
+    func run() async throws {
+        do {
+            let localStorage = VMStorageLocal()
+
+            if !localStorage.exists(name) {
+                throw ValidationError("failed to rename a non-existent VM: \(name)")
+            }
+
+            if localStorage.exists(newName) {
+                throw ValidationError("failed to rename VM \(name), target VM \(name) already exists, delete it first!")
+            }
+
+            try localStorage.rename(name, newName)
+
+            Foundation.exit(0)
+        } catch {
+            print(error)
+
+            Foundation.exit(1)
+        }
+    }
+}

Sources/tart/Commands/Run.swift

@@ -19,6 +19,9 @@ struct Run: AsyncParsableCommand {
           discussion: "Useful for integrating Tart VMs into other tools.\nUse `tart ip` in order to get an IP for SSHing or VNCing into the VM.")) 
   var noGraphics: Bool = false
 
+  @Flag(help: "Force open a UI window, even when VNC is enabled.")
+  var graphics: Bool = false
+
   @Flag(help: "Boot into recovery mode") 
   var recovery: Bool = false
   
@@ -37,17 +40,42 @@ struct Run: AsyncParsableCommand {
   @Flag var withSoftnet: Bool = false
 
   @Option(help: ArgumentHelp("""
-    Additional disk attachments with an optional read-only specifier\n(e.g. --disk=\"disk.bin\" --disk=\"disk.bin:ro\")
+    Additional disk attachments with an optional read-only specifier\n(e.g. --disk=\"disk.bin\" --disk=\"ubuntu.iso:ro\")
     """, discussion: """
     Learn how to create a disk image using Disk Utility here:
     https://support.apple.com/en-gb/guide/disk-utility/dskutl11888/mac
-    """))
+    """, valueName: "path[:ro]"))
   var disk: [String] = []
 
+  @Option(help: ArgumentHelp("""
+                             Additional directory shares with an optional read-only specifier\n(e.g. --dir=\"build:~/src/build\" --dir=\"sources:~/src/sources:ro\")
+                             """, discussion: """
+                                              Requires host to be macOS 13.0 (Ventura) or newer.
+                                              All shared directories are automatically mounted to "/Volumes/My Shared Files" directory on macOS,
+                                              while on Linux you have to do it manually: "mount -t virtiofs com.apple.virtio-fs.automount /mount/point".
+                                              For macOS guests, they must be running macOS 13.0 (Ventura) or newer.
+                                              """, valueName: "name:path[:ro]"))
+  var dir: [String] = []
+
+  @Option(help: ArgumentHelp("""
+                             Use bridged networking instead of the default shared (NAT) networking \n(e.g. --net-bridged=en0 or --net-bridged=\"Wi-Fi\")
+                             """, discussion: """
+                                              Specify "list" as an interface name (--net-bridged=list) to list the available bridged interfaces.
+                                              """, valueName: "interface name"))
+  var netBridged: String?
+
   func validate() throws {
     if vnc && vncExperimental {
       throw ValidationError("--vnc and --vnc-experimental are mutually exclusive")
     }
+
+    if withSoftnet && netBridged != nil {
+      throw ValidationError("--with-softnet and --net-bridged are mutually exclusive")
+    }
+
+    if graphics && noGraphics {
+      throw ValidationError("--graphics and --no-graphics are mutually exclusive")
+    }
   }
 
   @MainActor
@@ -55,8 +83,9 @@ struct Run: AsyncParsableCommand {
     let vmDir = try VMStorageLocal().open(name)
     vm = try VM(
       vmDir: vmDir,
-      withSoftnet: withSoftnet,
-      additionalDiskAttachments: additionalDiskAttachments()
+      network: userSpecifiedNetwork(vmDir: vmDir) ?? NetworkShared(),
+      additionalDiskAttachments: additionalDiskAttachments(),
+      directoryShares: directoryShares()
     )
 
     let vncImpl: VNC? = try {
@@ -107,18 +136,61 @@ struct Run: AsyncParsableCommand {
     }
     sigintSrc.activate()
 
-    if noGraphics || vnc || vncExperimental {
+    let useVNCWithoutGraphics = (vnc || vncExperimental) && !graphics
+    if noGraphics || useVNCWithoutGraphics {
       dispatchMain()
     } else {
       runUI()
     }
   }
 
+  func userSpecifiedNetwork(vmDir: VMDirectory) throws -> Network? {
+    if withSoftnet {
+      let config = try VMConfig.init(fromURL: vmDir.configURL)
+
+      return try Softnet(vmMACAddress: config.macAddress.string)
+    }
+
+    if let netBridged = netBridged {
+      let matchingInterfaces = VZBridgedNetworkInterface.networkInterfaces.filter { interface in
+        interface.identifier == netBridged || interface.localizedDisplayName == netBridged
+      }
+
+      if matchingInterfaces.isEmpty {
+        let available = bridgeInterfaces().joined(separator: ", ")
+        throw ValidationError("no bridge interfaces matched \"\(netBridged)\", "
+          + "available interfaces: \(available)")
+      }
+
+      if matchingInterfaces.count > 1 {
+        throw ValidationError("more than one bridge interface matched \"\(netBridged)\", "
+          + "consider refining the search criteria")
+      }
+
+      return NetworkBridged(interface: matchingInterfaces.first!)
+    }
+
+    return nil
+  }
+
+  func bridgeInterfaces() -> [String] {
+    VZBridgedNetworkInterface.networkInterfaces.map { interface in
+      var bridgeDescription = interface.identifier
+
+      if let localizedDisplayName = interface.localizedDisplayName {
+        bridgeDescription += " (or \"\(localizedDisplayName)\")"
+      }
+
+      return bridgeDescription
+    }
+  }
+
   func additionalDiskAttachments() throws -> [VZDiskImageStorageDeviceAttachment] {
     var result: [VZDiskImageStorageDeviceAttachment] = []
     let readOnlySuffix = ":ro"
+    let expandedDiskPaths = disk.map { NSString(string:$0).expandingTildeInPath }
 
-    for rawDisk in disk {
+    for rawDisk in expandedDiskPaths {
       if rawDisk.hasSuffix(readOnlySuffix) {
         result.append(try VZDiskImageStorageDeviceAttachment(
           url: URL(fileURLWithPath: String(rawDisk.prefix(rawDisk.count - readOnlySuffix.count))),
@@ -135,6 +207,34 @@ struct Run: AsyncParsableCommand {
     return result
   }
 
+  func directoryShares() throws -> [DirectoryShare] {
+    var result: [DirectoryShare] = []
+
+    for rawDir in dir {
+      let splits = rawDir.split(maxSplits: 2) { $0 == ":" }
+
+      if splits.count < 2 {
+        throw ValidationError("invalid --dir syntax: should at least include name and path, colon-separated")
+      }
+
+      var readOnly: Bool = false
+
+      if splits.count == 3 {
+        if splits[2] == "ro" {
+          readOnly = true
+        } else {
+          throw ValidationError("invalid --dir syntax: optional read-only specifier can only be \"ro\"")
+        }
+      }
+
+      let (name, path) = (String(splits[0]), String(splits[1]))
+
+      result.append(DirectoryShare(name: name, path: URL(fileURLWithPath: NSString(string: path).expandingTildeInPath), readOnly: readOnly))
+    }
+
+    return result
+  }
+
   private func runUI() {
     let nsApp = NSApplication.shared
     nsApp.setActivationPolicy(.regular)
@@ -148,6 +248,8 @@ struct Run: AsyncParsableCommand {
           Group {
             VMView(vm: vm!).onAppear {
               NSWindow.allowsAutomaticWindowTabbing = false
+            }.onDisappear {
+              NSApplication.shared.terminate(self)
             }
           }.frame(width: CGFloat(vm!.config.display.width), height: CGFloat(vm!.config.display.height))
         }.commands {

Sources/tart/Config.swift

@@ -3,8 +3,9 @@ import Foundation
 struct Config {
   let tartHomeDir: URL
   let tartCacheDir: URL
+  let tartTmpDir: URL
 
-  init() {
+  init() throws {
     var tartHomeDir: URL
 
     if let customTartHome = ProcessInfo.processInfo.environment["TART_HOME"] {
@@ -14,9 +15,27 @@ struct Config {
               .homeDirectoryForCurrentUser
               .appendingPathComponent(".tart", isDirectory: true)
     }
-
     self.tartHomeDir = tartHomeDir
+
     tartCacheDir = tartHomeDir.appendingPathComponent("cache", isDirectory: true)
+    try FileManager.default.createDirectory(at: tartCacheDir, withIntermediateDirectories: true)
+
+    tartTmpDir = tartHomeDir.appendingPathComponent("tmp", isDirectory: true)
+    try FileManager.default.createDirectory(at: tartTmpDir, withIntermediateDirectories: true)
+  }
+
+  func gc() throws {
+    for entry in try FileManager.default.contentsOfDirectory(at: tartTmpDir,
+        includingPropertiesForKeys: [], options: []) {
+      let lock = try FileLock(lockURL: entry)
+      if try !lock.trylock() {
+        continue
+      }
+
+      try FileManager.default.removeItem(at: entry)
+
+      try lock.unlock()
+    }
   }
 
   static func jsonEncoder() -> JSONEncoder {

Sources/tart/Credentials/DockerConfigCredentialsProvider.swift

@@ -0,0 +1,88 @@
+import Foundation
+
+class DockerConfigCredentialsProvider: CredentialsProvider {
+  func retrieve(host: String) throws -> (String, String)? {
+    let dockerConfigURL = FileManager.default.homeDirectoryForCurrentUser.appendingPathComponent(".docker").appendingPathComponent("config.json")
+    if !FileManager.default.fileExists(atPath: dockerConfigURL.path) {
+      return nil
+    }
+    let config = try JSONDecoder().decode(DockerConfig.self, from: Data(contentsOf: dockerConfigURL))
+
+    if let credentialsFromAuth = config.auths?[host]?.decodeCredentials() {
+      return credentialsFromAuth
+    }
+    if let helperProgram = config.credHelpers?[host] {
+      return try executeHelper(binaryName: "docker-credential-\(helperProgram)", host: host)
+    }
+
+    return nil
+  }
+
+  private func executeHelper(binaryName: String, host: String) throws -> (String, String)? {
+    guard let executableURL = resolveBinaryPath(binaryName) else {
+      throw CredentialsProviderError.Failed(message: "\(binaryName) not found in PATH")
+    }
+    
+    let process = Process.init()
+    process.executableURL = executableURL
+    process.arguments = ["get"]
+
+    let outPipe = Pipe()
+    let inPipe = Pipe()
+    
+    process.standardOutput = outPipe
+    process.standardError = outPipe
+    process.standardInput = inPipe
+
+    process.launch()
+
+    inPipe.fileHandleForWriting.write("\(host)\n".data(using: .utf8)!)
+    inPipe.fileHandleForWriting.closeFile()
+    
+    process.waitUntilExit()
+
+    if !(process.terminationReason == .exit && process.terminationStatus == 0) {
+      throw CredentialsProviderError.Failed(message: "Docker helper failed!")
+    }
+
+    let getOutput = try JSONDecoder().decode(
+      DockerGetOutput.self, from: outPipe.fileHandleForReading.readDataToEndOfFile()
+    )
+    return (getOutput.Username, getOutput.Secret)
+  }
+
+  func store(host: String, user: String, password: String) throws {
+    throw CredentialsProviderError.Failed(message: "Docker helpers don't support storing!")
+  }
+}
+
+struct DockerConfig: Codable {
+  var auths: Dictionary<String, DockerAuthConfig>? = Dictionary()
+  var credHelpers: Dictionary<String, String>? = Dictionary()
+}
+
+struct DockerAuthConfig: Codable {
+  var auth: String? = nil
+
+  func decodeCredentials() -> (String, String)? {
+    // auth is a base64("username:password")
+    guard let authBase64 = auth else {
+      return nil
+    }
+    guard let data = Data(base64Encoded: authBase64) else {
+      return nil
+    }
+    guard let components = String(data: data, encoding: .utf8)?.components(separatedBy: ":") else {
+      return nil
+    }
+    if components.count != 2 {
+      return nil
+    }
+    return (components[0], components[1])
+  }
+}
+
+struct DockerGetOutput: Codable {
+  var Username: String
+  var Secret: String
+}

Sources/tart/FileLock.swift

@@ -0,0 +1,48 @@
+import Foundation
+import System
+
+enum FileLockError: Error, Equatable {
+    case Failed(_ message: String)
+    case AlreadyLocked
+}
+
+class FileLock {
+    let url: URL
+    let fd: Int32
+
+    init(lockURL: URL) throws {
+        url = lockURL
+        fd = open(lockURL.path, 0)
+    }
+
+    deinit {
+        close(fd)
+    }
+
+    func trylock() throws -> Bool {
+        try flockWrapper(LOCK_EX | LOCK_NB)
+    }
+
+    func lock() throws {
+        _ = try flockWrapper(LOCK_EX)
+    }
+
+    func unlock() throws {
+        _ = try flockWrapper(LOCK_UN)
+    }
+
+    func flockWrapper(_ operation: Int32) throws -> Bool {
+        let ret = flock(fd, operation)
+        if ret != 0 {
+            let details = Errno(rawValue: CInt(errno))
+
+            if (operation & LOCK_NB) != 0 && details == .wouldBlock {
+                return false
+            }
+
+            throw FileLockError.Failed("failed to lock \(url): \(details)")
+        }
+
+        return true
+    }
+}

Sources/tart/IPSWCache.swift

@@ -5,7 +5,7 @@ class IPSWCache: PrunableStorage {
   let baseURL: URL
 
   init() throws {
-    baseURL = Config().tartCacheDir.appendingPathComponent("IPSWs", isDirectory: true)
+    baseURL = try Config().tartCacheDir.appendingPathComponent("IPSWs", isDirectory: true)
     try FileManager.default.createDirectory(at: baseURL, withIntermediateDirectories: true)
   }
 

Sources/tart/MACAddressResolver/ARPCache.swift

@@ -0,0 +1,119 @@
+import Foundation
+import Network
+import Virtualization
+
+struct ARPCommandFailedError: Error, CustomStringConvertible {
+    var terminationReason: Process.TerminationReason
+    var terminationStatus: Int32
+
+    var description: String {
+        var reason: String
+
+        switch terminationReason {
+        case .exit:
+            reason = "exit code \(terminationStatus)"
+        case .uncaughtSignal:
+            reason = "uncaught signal"
+        default:
+            reason = "unknown reason"
+        }
+
+        return "arp command failed: \(reason)"
+    }
+}
+
+struct ARPCommandYieldedInvalidOutputError: Error, CustomStringConvertible {
+    var explanation: String
+
+    var description: String {
+        "arp command yielded invalid output: \(explanation)"
+    }
+}
+
+struct ARPCacheInternalError: Error, CustomStringConvertible {
+    var explanation: String
+
+    var description: String {
+        "ARPCache internal error: \(explanation)"
+    }
+}
+
+struct ARPCache {
+    static func ResolveMACAddress(macAddress: MACAddress, bridgeOnly: Bool = true) throws -> IPv4Address? {
+        let process = Process.init()
+        process.executableURL = URL.init(fileURLWithPath: "/usr/sbin/arp")
+        process.arguments = ["-an"]
+
+        let pipe = Pipe()
+        process.standardOutput = pipe
+        process.standardError = pipe
+        process.standardInput = FileHandle.nullDevice
+
+        try process.run()
+        process.waitUntilExit()
+
+        if !(process.terminationReason == .exit && process.terminationStatus == 0) {
+            throw ARPCommandFailedError(
+                    terminationReason: process.terminationReason,
+                    terminationStatus: process.terminationStatus)
+        }
+
+        guard let rawLines = try pipe.fileHandleForReading.readToEnd() else {
+            throw ARPCommandYieldedInvalidOutputError(explanation: "empty output")
+        }
+        let lines = String(decoding: rawLines, as: UTF8.self)
+                .trimmingCharacters(in: .whitespacesAndNewlines)
+                .components(separatedBy: "\n")
+
+        // Based on https://opensource.apple.com/source/network_cmds/network_cmds-606.40.2/arp.tproj/arp.c.auto.html
+        let regex = try NSRegularExpression(pattern: #"^.* \((?<ip>.*)\) at (?<mac>.*) on (?<interface>.*) .*$"#)
+
+        for line in lines {
+            let nsLineRange = NSRange(line.startIndex..<line.endIndex, in: line)
+
+            guard let match = regex.firstMatch(in: line, range: nsLineRange) else {
+                throw ARPCommandYieldedInvalidOutputError(explanation: "unparseable entry \"\(line)\"")
+            }
+
+            let rawIP = try match.getCaptureGroup(name: "ip", for: line)
+            guard let ip = IPv4Address(rawIP) else {
+                throw ARPCommandYieldedInvalidOutputError(explanation: "failed to parse IPv4 address \(rawIP)")
+            }
+
+            let rawMAC = try match.getCaptureGroup(name: "mac", for: line)
+            if rawMAC == "(incomplete)" {
+                continue
+            }
+            guard let mac = MACAddress(fromString: rawMAC) else {
+                throw ARPCommandYieldedInvalidOutputError(explanation: "failed to parse MAC address \(rawMAC)")
+            }
+
+            let interface = try match.getCaptureGroup(name: "interface", for: line)
+            if bridgeOnly && !interface.starts(with: "bridge") {
+                continue
+            }
+
+            if macAddress == mac {
+                return ip
+            }
+        }
+
+        return nil
+    }
+}
+
+extension NSTextCheckingResult {
+    func getCaptureGroup(name: String, for string: String) throws -> String {
+        let nsRange = self.range(withName: name)
+
+        if nsRange.location == NSNotFound {
+            throw ARPCacheInternalError(explanation: "attempted to retrieve non-existent named capture group \(name)")
+        }
+
+        guard let range = Range.init(nsRange, in: string) else {
+            throw ARPCacheInternalError(explanation: "failed to convert NSRange to Range")
+        }
+
+        return String(string[range])
+    }
+}

Sources/tart/MACAddressResolver/Leases.swift

@@ -19,14 +19,21 @@ enum LeasesError: Error {
 class Leases {
   private let leases: [MACAddress : Lease]
 
-  convenience init() throws {
+  convenience init?() throws {
     try self.init(URL(fileURLWithPath: "/var/db/dhcpd_leases"))
   }
 
-  convenience init(_ fromURL: URL) throws {
-    let fileContents = try String(contentsOf: fromURL, encoding: .utf8)
+  convenience init?(_ fromURL: URL) throws {
+    do {
+      let urlContents = try String(contentsOf: fromURL, encoding: .utf8)
+      try self.init(urlContents)
+    } catch {
+      if error.isFileNotFound() {
+        return nil
+      }
 
-    try self.init(fileContents)
+      throw error
+    }
   }
 
   init(_ fromString: String) throws {

Sources/tart/MACAddressResolver/MACAddress.swift

@@ -16,6 +16,6 @@ struct MACAddress: Equatable, Hashable, CustomStringConvertible {
   }
 
   var description: String {
-    return String(format: "%02x:%02x:%02x:%02x:%02x:%02x", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5])
+    String(format: "%02x:%02x:%02x:%02x:%02x:%02x", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5])
   }
 }

Sources/tart/Network/Network.swift

@@ -0,0 +1,7 @@
+import Virtualization
+
+protocol Network {
+  func attachment() -> VZNetworkDeviceAttachment
+  func run() throws
+  func stop() throws
+}

Sources/tart/Network/NetworkBridged.swift

@@ -0,0 +1,22 @@
+import Foundation
+import Virtualization
+
+class NetworkBridged: Network {
+    let interface: VZBridgedNetworkInterface
+
+    init(interface: VZBridgedNetworkInterface) {
+        self.interface = interface
+    }
+
+    func attachment() -> VZNetworkDeviceAttachment {
+        VZBridgedNetworkDeviceAttachment(interface: interface)
+    }
+
+    func run() throws {
+        // no-op, only used for Softnet
+    }
+
+    func stop() throws {
+        // no-op, only used for Softnet
+    }
+}

Sources/tart/Network/NetworkShared.swift

@@ -0,0 +1,16 @@
+import Foundation
+import Virtualization
+
+class NetworkShared: Network {
+    func attachment() -> VZNetworkDeviceAttachment {
+        VZNATNetworkDeviceAttachment()
+    }
+
+    func run() throws {
+        // no-op, only used for Softnet
+    }
+
+    func stop() throws {
+        // no-op, only used for Softnet
+    }
+}

Sources/tart/Network/Softnet.swift

@@ -1,10 +1,11 @@
 import Foundation
+import Virtualization
 
 enum SoftnetError: Error {
   case InitializationFailed(why: String)
 }
 
-class Softnet {
+class Softnet: Network {
   private let process = Process()
 
   let vmFD: Int32
@@ -12,7 +13,7 @@ class Softnet {
   init(vmMACAddress: String) throws {
     let binaryName = "softnet"
 
-    guard let executableURL = Self.resolveBinaryPath(binaryName) else {
+    guard let executableURL = resolveBinaryPath(binaryName) else {
       throw SoftnetError.InitializationFailed(why: "\(binaryName) not found in PATH")
     }
 
@@ -43,23 +44,6 @@ class Softnet {
     process.waitUntilExit()
   }
 
-  private static func resolveBinaryPath(_ name: String) -> URL? {
-    guard let path = ProcessInfo.processInfo.environment["PATH"] else {
-      return nil
-    }
-
-    for pathComponent in path.split(separator: ":") {
-      let url = URL(fileURLWithPath: String(pathComponent))
-              .appendingPathComponent(name, isDirectory: false)
-
-      if FileManager.default.fileExists(atPath: url.path) {
-        return url
-      }
-    }
-
-    return nil
-  }
-
   private func setSocketBuffers(_ fd: Int32, _ sizeBytes: Int) throws {
     var option_value = sizeBytes
     let option_len = socklen_t(MemoryLayout<Int>.size)
@@ -74,4 +58,9 @@ class Softnet {
       throw SoftnetError.InitializationFailed(why: "setsockopt(SO_SNDBUF) returned \(ret)")
     }
   }
+
+  func attachment() -> VZNetworkDeviceAttachment {
+    let fh = FileHandle.init(fileDescriptor: vmFD)
+    return VZFileHandleNetworkDeviceAttachment(fileHandle: fh)
+  }
 }

Sources/tart/OCI/Manifest.swift

@@ -46,8 +46,8 @@ struct OCIManifest: Codable, Equatable {
 }
 
 struct OCIConfig: Codable {
-  var architecture: String = "arm64"
-  var os: String = "darwin"
+  var architecture: Architecture = .arm64
+  var os: OS = .darwin
 
   func toJSON() throws -> Data {
     try Config.jsonEncoder().encode(self)

Sources/tart/OCI/Registry.swift

@@ -88,29 +88,29 @@ class Registry {
 
   let baseURL: URL
   let namespace: String
-  let credentialsProvider: CredentialsProvider
+  let credentialsProviders: [CredentialsProvider]
 
   var currentAuthToken: Authentication? = nil
 
   init(urlComponents: URLComponents,
        namespace: String,
-       credentialsProvider: CredentialsProvider = KeychainCredentialsProvider()
+       credentialsProviders: [CredentialsProvider] = [DockerConfigCredentialsProvider(), KeychainCredentialsProvider()]
   ) throws {
     baseURL = urlComponents.url!
     self.namespace = namespace
-    self.credentialsProvider = credentialsProvider
+    self.credentialsProviders = credentialsProviders
   }
 
   convenience init(
     host: String,
     namespace: String,
     insecure: Bool = false,
-    credentialsProvider: CredentialsProvider = KeychainCredentialsProvider()
+    credentialsProviders: [CredentialsProvider] = [DockerConfigCredentialsProvider(), KeychainCredentialsProvider()]
   ) throws {
     let proto = insecure ? "http" : "https"
     let baseURLComponents = URLComponents(string: proto + "://" + host + "/v2/")!
 
-    try self.init(urlComponents: baseURLComponents, namespace: namespace, credentialsProvider: credentialsProvider)
+    try self.init(urlComponents: baseURLComponents, namespace: namespace, credentialsProviders: credentialsProviders)
   }
 
   func ping() async throws {
@@ -303,7 +303,7 @@ class Registry {
     let wwwAuthenticate = try WWWAuthenticate(rawHeaderValue: wwwAuthenticateRaw)
 
     if wwwAuthenticate.scheme == "Basic" {
-      if let (user, password) = try credentialsProvider.retrieve(host: baseURL.host!) {
+      if let (user, password) = try lookupCredentials(host: baseURL.host!) {
         currentAuthToken = BasicAuthentication(user: user, password: password)
       }
 
@@ -340,7 +340,7 @@ class Registry {
 
     var headers: Dictionary<String, String> = Dictionary()
 
-    if let (user, password) = try credentialsProvider.retrieve(host: baseURL.host!) {
+    if let (user, password) = try lookupCredentials(host: baseURL.host!) {
       let encodedCredentials = "\(user):\(password)".data(using: .utf8)?.base64EncodedString()
       headers["Authorization"] = "Basic \(encodedCredentials!)"
     }
@@ -356,6 +356,15 @@ class Registry {
     currentAuthToken = try TokenResponse.parse(fromData: bodyData)
   }
 
+  private func lookupCredentials(host: String) throws -> (String, String)? {
+    for provider in credentialsProviders {
+      if let (user, password) = try provider.retrieve(host: host) {
+        return (user, password)
+      }
+    }
+    return nil
+  }
+
   private func authAwareRequest(request: HTTPClientRequest) async throws -> HTTPClientResponse {
     var request = request
 

Sources/tart/Platform/Architecture.swift

@@ -0,0 +1,14 @@
+import Foundation
+
+enum Architecture: String, Codable {
+    case arm64
+    case amd64
+}
+
+func CurrentArchitecture() -> Architecture {
+    #if arch(arm64)
+        return .arm64
+    #elseif arch(x86_64)
+        return .amd64
+    #endif
+}

Sources/tart/Platform/Darwin.swift

@@ -0,0 +1,97 @@
+import Virtualization
+
+struct Darwin: Platform {
+    var ecid: VZMacMachineIdentifier
+    var hardwareModel: VZMacHardwareModel
+
+    init(ecid: VZMacMachineIdentifier, hardwareModel: VZMacHardwareModel) {
+        self.ecid = ecid
+        self.hardwareModel = hardwareModel
+    }
+
+    init(from decoder: Decoder) throws {
+        let container = try decoder.container(keyedBy: CodingKeys.self)
+
+        let encodedECID = try container.decode(String.self, forKey: .ecid)
+        guard let data = Data.init(base64Encoded: encodedECID) else {
+            throw DecodingError.dataCorruptedError(forKey: .ecid,
+                    in: container,
+                    debugDescription: "failed to initialize Data using the provided value")
+        }
+        guard let ecid = VZMacMachineIdentifier.init(dataRepresentation: data) else {
+            throw DecodingError.dataCorruptedError(forKey: .ecid,
+                    in: container,
+                    debugDescription: "failed to initialize VZMacMachineIdentifier using the provided value")
+        }
+        self.ecid = ecid
+
+        let encodedHardwareModel = try container.decode(String.self, forKey: .hardwareModel)
+        guard let data = Data.init(base64Encoded: encodedHardwareModel) else {
+            throw DecodingError.dataCorruptedError(forKey: .hardwareModel, in: container, debugDescription: "")
+        }
+        guard let hardwareModel = VZMacHardwareModel.init(dataRepresentation: data) else {
+            throw DecodingError.dataCorruptedError(forKey: .hardwareModel, in: container, debugDescription: "")
+        }
+        self.hardwareModel = hardwareModel
+    }
+
+    func encode(to encoder: Encoder) throws {
+        var container = encoder.container(keyedBy: CodingKeys.self)
+
+        try container.encode(ecid.dataRepresentation.base64EncodedString(), forKey: .ecid)
+        try container.encode(hardwareModel.dataRepresentation.base64EncodedString(), forKey: .hardwareModel)
+    }
+
+    func os() -> OS {
+        .darwin
+    }
+
+    func bootLoader(nvramURL: URL) throws -> VZBootLoader {
+        VZMacOSBootLoader()
+    }
+
+    func platform(nvramURL: URL) -> VZPlatformConfiguration {
+        let result = VZMacPlatformConfiguration()
+
+        result.machineIdentifier = ecid
+        result.auxiliaryStorage = VZMacAuxiliaryStorage(contentsOf: nvramURL)
+        result.hardwareModel = hardwareModel
+
+        return result
+    }
+
+    func graphicsDevice(vmConfig: VMConfig) -> VZGraphicsDeviceConfiguration {
+        let result = VZMacGraphicsDeviceConfiguration()
+
+        if let hostMainScreen = NSScreen.main {
+            let vmScreenSize = NSSize(width: vmConfig.display.width, height: vmConfig.display.height)
+            result.displays = [
+                VZMacGraphicsDisplayConfiguration(for: hostMainScreen, sizeInPoints: vmScreenSize)
+            ]
+
+            return result
+        }
+
+        result.displays = [
+            VZMacGraphicsDisplayConfiguration(
+                    widthInPixels: vmConfig.display.width,
+                    heightInPixels: vmConfig.display.height,
+                    // A reasonable guess according to Apple's documentation[1]
+                    // [1]: https://developer.apple.com/documentation/coregraphics/1456599-cgdisplayscreensize
+                    pixelsPerInch: 72
+            )
+        ]
+
+        return result
+    }
+
+    func pointingDevices() -> [VZPointingDeviceConfiguration] {
+        if #available(macOS 13, *) {
+            // Trackpad is only supported starting with macOS Ventura
+            // macOS Monterey will continue using a USB device == .darwin 
+            return [VZMacTrackpadConfiguration(), VZUSBScreenCoordinatePointingDeviceConfiguration()]
+        } else {
+            return [VZUSBScreenCoordinatePointingDeviceConfiguration()]
+        }
+    }
+}

Sources/tart/Platform/Linux.swift

@@ -0,0 +1,37 @@
+import Virtualization
+
+@available(macOS 13, *)
+struct Linux: Platform {
+    func os() -> OS {
+        .linux
+    }
+
+    func bootLoader(nvramURL: URL) throws -> VZBootLoader {
+        let result = VZEFIBootLoader()
+
+        result.variableStore = VZEFIVariableStore(url: nvramURL)
+
+        return result
+    }
+
+    func platform(nvramURL: URL) -> VZPlatformConfiguration {
+        VZGenericPlatformConfiguration()
+    }
+
+    func graphicsDevice(vmConfig: VMConfig) -> VZGraphicsDeviceConfiguration {
+        let result = VZVirtioGraphicsDeviceConfiguration()
+
+        result.scanouts = [
+            VZVirtioGraphicsScanoutConfiguration(
+                    widthInPixels: vmConfig.display.width,
+                    heightInPixels: vmConfig.display.height
+            )
+        ]
+
+        return result
+    }
+
+    func pointingDevices() -> [VZPointingDeviceConfiguration] {
+        [VZUSBScreenCoordinatePointingDeviceConfiguration()]
+    }
+}

Sources/tart/Platform/OS.swift

@@ -0,0 +1,6 @@
+import Virtualization
+
+enum OS: String, Codable {
+    case darwin
+    case linux
+}

Sources/tart/Platform/Platform.swift

@@ -0,0 +1,9 @@
+import Virtualization
+
+protocol Platform: Codable {
+    func os() -> OS
+    func bootLoader(nvramURL: URL) throws -> VZBootLoader
+    func platform(nvramURL: URL) -> VZPlatformConfiguration
+    func graphicsDevice(vmConfig: VMConfig) -> VZGraphicsDeviceConfiguration
+    func pointingDevices() -> [VZPointingDeviceConfiguration]
+}

Sources/tart/Root.swift

@@ -17,6 +17,7 @@ struct Root: AsyncParsableCommand {
       Pull.self,
       Push.self,
       Prune.self,
+      Rename.self,
       Delete.self,
     ])
 
@@ -32,10 +33,16 @@ struct Root: AsyncParsableCommand {
     }
     sigintSrc.activate()
 
+    // Set line-buffered output for stdout
+    setlinebuf(stdout)
+
     // Parse and run command
     do {
       var command = try parseAsRoot()
 
+      // Run garbage-collection before each command (shouldn't take too long)
+      try Config().gc()
+
       if var asyncCommand = command as? AsyncParsableCommand {
         try await asyncCommand.run()
       } else {

Sources/tart/URL+AccessDate.swift

@@ -20,6 +20,6 @@ extension URL {
 
 extension Date {
   func asTimeval() -> timeval {
-    timeval(tv_sec: timeIntervalSince1970.toUnit(.second)!, tv_usec: 0)
+    timeval(tv_sec: Int(timeIntervalSince1970), tv_usec: 0)
   }
 }

Sources/tart/Utils.swift

@@ -5,3 +5,20 @@ extension Collection {
     indices.contains(index) ? self[index] : nil
   }
 }
+
+func resolveBinaryPath(_ name: String) -> URL? {
+  guard let path = ProcessInfo.processInfo.environment["PATH"] else {
+    return nil
+  }
+
+  for pathComponent in path.split(separator: ":") {
+    let url = URL(fileURLWithPath: String(pathComponent))
+            .appendingPathComponent(name, isDirectory: false)
+
+    if FileManager.default.fileExists(atPath: url.path) {
+      return url
+    }
+  }
+
+  return nil
+}

Sources/tart/VM.swift

@@ -10,6 +10,17 @@ struct NoMainScreenFoundError: Error {
 struct DownloadFailed: Error {
 }
 
+struct UnsupportedOSError: Error, CustomStringConvertible {
+  let description: String
+
+  init(_ what: String, _ plural: String) {
+    description = "error: \(what) \(plural) only supported on hosts running macOS 13.0 (Ventura) or newer"
+  }
+}
+
+struct UnsupportedArchitectureError: Error {
+}
+
 class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
   // Virtualization.Framework's virtual machine
   @Published var virtualMachine: VZVirtualMachine
@@ -23,24 +34,26 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
   // VM's config
   var config: VMConfig
 
-  var softnet: Softnet? = nil
+  var network: Network
 
   init(vmDir: VMDirectory,
-       withSoftnet: Bool = false,
-       additionalDiskAttachments: [VZDiskImageStorageDeviceAttachment] = []
+       network: Network = NetworkShared(),
+       additionalDiskAttachments: [VZDiskImageStorageDeviceAttachment] = [],
+       directoryShares: [DirectoryShare] = []
   ) throws {
-    let auxStorage = VZMacAuxiliaryStorage(contentsOf: vmDir.nvramURL)
-
     name = vmDir.name
     config = try VMConfig.init(fromURL: vmDir.configURL)
 
-    // Initialize the virtual machine and its configuration
-    if withSoftnet {
-      softnet = try Softnet(vmMACAddress: config.macAddress.string)
+    if config.arch != CurrentArchitecture() {
+      throw UnsupportedArchitectureError()
     }
 
-    let configuration = try Self.craftConfiguration(diskURL: vmDir.diskURL, auxStorage: auxStorage, vmConfig: config,
-      softnet: softnet, additionalDiskAttachments: additionalDiskAttachments)
+    // Initialize the virtual machine and its configuration
+    self.network = network
+    let configuration = try Self.craftConfiguration(diskURL: vmDir.diskURL,
+      nvramURL: vmDir.nvramURL, vmConfig: config,
+      network: network, additionalDiskAttachments: additionalDiskAttachments,
+            directoryShares: directoryShares)
     virtualMachine = VZVirtualMachine(configuration: configuration)
 
     super.init()
@@ -98,7 +111,7 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     vmDir: VMDirectory,
     ipswURL: URL?,
     diskSizeGB: UInt16,
-    withSoftnet: Bool = false,
+    network: Network = NetworkShared(),
     additionalDiskAttachments: [VZDiskImageStorageDeviceAttachment] = []
   ) async throws {
     let ipswURL = ipswURL != nil ? ipswURL! : try await VM.retrieveLatestIPSW();
@@ -116,7 +129,7 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     }
 
     // Create NVRAM
-    let auxStorage = try VZMacAuxiliaryStorage(creatingStorageAt: vmDir.nvramURL, hardwareModel: requirements.hardwareModel)
+    _ = try VZMacAuxiliaryStorage(creatingStorageAt: vmDir.nvramURL, hardwareModel: requirements.hardwareModel)
 
     // Create disk
     try vmDir.resizeDisk(diskSizeGB)
@@ -124,7 +137,7 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     name = vmDir.name
     // Create config
     config = VMConfig(
-      hardwareModel: requirements.hardwareModel,
+      platform: Darwin(ecid: VZMacMachineIdentifier(), hardwareModel: requirements.hardwareModel),
       cpuCountMin: requirements.minimumSupportedCPUCount,
       memorySizeMin: requirements.minimumSupportedMemorySize
     )
@@ -133,12 +146,11 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     try config.save(toURL: vmDir.configURL)
 
     // Initialize the virtual machine and its configuration
-    if withSoftnet {
-      softnet = try Softnet(vmMACAddress: config.macAddress.string)
-    }
-
-    let configuration = try Self.craftConfiguration(diskURL: vmDir.diskURL, auxStorage: auxStorage, vmConfig: config,
-      softnet: softnet, additionalDiskAttachments: additionalDiskAttachments)
+    self.network = network
+    let configuration = try Self.craftConfiguration(diskURL: vmDir.diskURL, nvramURL: vmDir.nvramURL,
+      vmConfig: config, network: network,
+      additionalDiskAttachments: additionalDiskAttachments,
+      directoryShares: [])
     virtualMachine = VZVirtualMachine(configuration: configuration)
 
     super.init()
@@ -159,10 +171,23 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     }
   }
 
+  @available(macOS 13, *)
+  static func linux(vmDir: VMDirectory, diskSizeGB: UInt16) async throws -> VM {
+    // Create NVRAM
+    _ = try VZEFIVariableStore(creatingVariableStoreAt: vmDir.nvramURL)
+
+    // Create disk
+    try vmDir.resizeDisk(diskSizeGB)
+
+    // Create config
+    let config = VMConfig(platform: Linux(), cpuCountMin: 4, memorySizeMin: 4096 * 1024 * 1024)
+    try config.save(toURL: vmDir.configURL)
+
+    return try VM(vmDir: vmDir)
+  }
+
   func run(_ recovery: Bool) async throws {
-    if let softnet = softnet {
-      try softnet.run()
-    }
+    try network.run()
 
     DispatchQueue.main.sync {
       Task {
@@ -192,57 +217,31 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
       }
     }
 
-    if let softnet = softnet {
-      try softnet.stop();
-    }
+    try network.stop()
   }
 
   static func craftConfiguration(
     diskURL: URL,
-    auxStorage: VZMacAuxiliaryStorage,
+    nvramURL: URL,
     vmConfig: VMConfig,
-    softnet: Softnet? = nil,
-    additionalDiskAttachments: [VZDiskImageStorageDeviceAttachment]
+    network: Network = NetworkShared(),
+    additionalDiskAttachments: [VZDiskImageStorageDeviceAttachment],
+    directoryShares: [DirectoryShare]
   ) throws -> VZVirtualMachineConfiguration {
     let configuration = VZVirtualMachineConfiguration()
 
     // Boot loader
-    configuration.bootLoader = VZMacOSBootLoader()
+    configuration.bootLoader = try vmConfig.platform.bootLoader(nvramURL: nvramURL)
 
     // CPU and memory
     configuration.cpuCount = vmConfig.cpuCount
     configuration.memorySize = vmConfig.memorySize
 
     // Platform
-    let platform = VZMacPlatformConfiguration()
-
-    platform.machineIdentifier = vmConfig.ecid
-    platform.auxiliaryStorage = auxStorage
-    platform.hardwareModel = vmConfig.hardwareModel
-
-    configuration.platform = platform
+    configuration.platform = vmConfig.platform.platform(nvramURL: nvramURL)
 
     // Display
-    let graphicsDeviceConfiguration = VZMacGraphicsDeviceConfiguration()
-    if let hostMainScreen = NSScreen.main {
-      let vmScreenSize = NSSize(
-        width: vmConfig.display.width,
-        height: vmConfig.display.height
-      )
-      graphicsDeviceConfiguration.displays = [
-        VZMacGraphicsDisplayConfiguration(for: hostMainScreen, sizeInPoints: vmScreenSize)
-      ]
-    } else {
-      graphicsDeviceConfiguration.displays = [
-        VZMacGraphicsDisplayConfiguration(
-          widthInPixels: vmConfig.display.width,
-          heightInPixels: vmConfig.display.height,
-          // Reasonable guess like https://developer.apple.com/documentation/coregraphics/1456599-cgdisplayscreensize    
-          pixelsPerInch: 72
-        )
-      ]
-    }
-    configuration.graphicsDevices = [graphicsDeviceConfiguration]
+    configuration.graphicsDevices = [vmConfig.platform.graphicsDevice(vmConfig: vmConfig)]
 
     // Audio
     let soundDeviceConfiguration = VZVirtioSoundDeviceConfiguration()
@@ -255,17 +254,11 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
 
     // Keyboard and mouse
     configuration.keyboards = [VZUSBKeyboardConfiguration()]
-    configuration.pointingDevices = [VZUSBScreenCoordinatePointingDeviceConfiguration()]
+    configuration.pointingDevices = vmConfig.platform.pointingDevices()
 
     // Networking
     let vio = VZVirtioNetworkDeviceConfiguration()
-
-    if let softnet = softnet {
-      let fh = FileHandle.init(fileDescriptor: softnet.vmFD)
-      vio.attachment = VZFileHandleNetworkDeviceAttachment(fileHandle: fh)
-    } else {
-      vio.attachment = VZNATNetworkDeviceAttachment()
-    }
+    vio.attachment = network.attachment()
     vio.macAddress = vmConfig.macAddress
     configuration.networkDevices = [vio]
 
@@ -277,6 +270,20 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     // Entropy
     configuration.entropyDevices = [VZVirtioEntropyDeviceConfiguration()]
 
+    // Directory share
+    if #available(macOS 13, *) {
+      var directories: [String : VZSharedDirectory] = Dictionary()
+      directoryShares.forEach { directories[$0.name] = VZSharedDirectory(url: $0.path, readOnly: $0.readOnly) }
+
+      let automountTag = VZVirtioFileSystemDeviceConfiguration.macOSGuestAutomountTag
+      let sharingDevice = VZVirtioFileSystemDeviceConfiguration(tag: automountTag)
+      sharingDevice.share = VZMultipleDirectoryShare(directories: directories)
+
+      configuration.directorySharingDevices = [sharingDevice]
+    } else if !directoryShares.isEmpty {
+      throw UnsupportedOSError("directory sharing", "is")
+    }
+
     try configuration.validate()
 
     return configuration
@@ -297,3 +304,9 @@ class VM: NSObject, VZVirtualMachineDelegate, ObservableObject {
     sema.signal()
   }
 }
+
+struct DirectoryShare {
+  let name: String
+  let path: URL
+  let readOnly: Bool
+}

Sources/tart/VMConfig.swift

@@ -16,14 +16,18 @@ class LessThanMinimalResourcesError: NSObject, LocalizedError {
 
 enum CodingKeys: String, CodingKey {
   case version
-  case ecid
-  case hardwareModel
+  case os
+  case arch
   case cpuCountMin
   case cpuCount
   case memorySizeMin
   case memorySize
   case macAddress
   case display
+
+  // macOS-specific keys
+  case ecid
+  case hardwareModel
 }
 
 struct VMDisplayConfig: Codable {
@@ -33,25 +37,25 @@ struct VMDisplayConfig: Codable {
 
 struct VMConfig: Codable {
   var version: Int = 1
-  var ecid: VZMacMachineIdentifier
-  var hardwareModel: VZMacHardwareModel
+  var os: OS
+  var arch: Architecture
+  var platform: Platform
   var cpuCountMin: Int
   private(set) var cpuCount: Int
   var memorySizeMin: UInt64
   private(set) var memorySize: UInt64
   var macAddress: VZMACAddress
-  
   var display: VMDisplayConfig = VMDisplayConfig()
 
   init(
-    ecid: VZMacMachineIdentifier = VZMacMachineIdentifier(),
-    hardwareModel: VZMacHardwareModel,
-    cpuCountMin: Int,
-    memorySizeMin: UInt64,
-    macAddress: VZMACAddress = VZMACAddress.randomLocallyAdministered()
+          platform: Platform,
+          cpuCountMin: Int,
+          memorySizeMin: UInt64,
+          macAddress: VZMACAddress = VZMACAddress.randomLocallyAdministered()
   ) {
-    self.ecid = ecid
-    self.hardwareModel = hardwareModel
+    self.os = platform.os()
+    self.arch = CurrentArchitecture()
+    self.platform = platform
     self.macAddress = macAddress
     self.cpuCountMin = cpuCountMin
     self.memorySizeMin = memorySizeMin
@@ -81,29 +85,18 @@ struct VMConfig: Codable {
     let container = try decoder.container(keyedBy: CodingKeys.self)
 
     version = try container.decode(Int.self, forKey: .version)
-
-    let encodedECID = try container.decode(String.self, forKey: .ecid)
-    guard let data = Data.init(base64Encoded: encodedECID) else {
-      throw DecodingError.dataCorruptedError(forKey: .ecid,
-                in: container,
-                debugDescription: "failed to initialize Data using the provided value")
+    os = try container.decodeIfPresent(OS.self, forKey: .os) ?? .darwin
+    arch = try container.decodeIfPresent(Architecture.self, forKey: .arch) ?? .arm64
+    switch os {
+    case .darwin:
+      platform = try Darwin(from: decoder)
+    case .linux:
+      if #available(macOS 13, *) {
+        platform = try Linux(from: decoder)
+      } else {
+        throw UnsupportedOSError("Linux VMs", "are")
+      }
     }
-    guard let ecid = VZMacMachineIdentifier.init(dataRepresentation: data) else {
-      throw DecodingError.dataCorruptedError(forKey: .ecid,
-                in: container,
-                debugDescription: "failed to initialize VZMacMachineIdentifier using the provided value")
-    }
-    self.ecid = ecid
-
-    let encodedHardwareModel = try container.decode(String.self, forKey: .hardwareModel)
-    guard let data = Data.init(base64Encoded: encodedHardwareModel) else {
-      throw DecodingError.dataCorruptedError(forKey: .hardwareModel, in: container, debugDescription: "")
-    }
-    guard let hardwareModel = VZMacHardwareModel.init(dataRepresentation: data) else {
-      throw DecodingError.dataCorruptedError(forKey: .hardwareModel, in: container, debugDescription: "")
-    }
-    self.hardwareModel = hardwareModel
-
     cpuCountMin = try container.decode(Int.self, forKey: .cpuCountMin)
     cpuCount = try container.decode(Int.self, forKey: .cpuCount)
     memorySizeMin = try container.decode(UInt64.self, forKey: .memorySizeMin)
@@ -125,8 +118,9 @@ struct VMConfig: Codable {
     var container = encoder.container(keyedBy: CodingKeys.self)
 
     try container.encode(version, forKey: .version)
-    try container.encode(ecid.dataRepresentation.base64EncodedString(), forKey: .ecid)
-    try container.encode(hardwareModel.dataRepresentation.base64EncodedString(), forKey: .hardwareModel)
+    try container.encode(os, forKey: .os)
+    try container.encode(arch, forKey: .arch)
+    try platform.encode(to: encoder)
     try container.encode(cpuCountMin, forKey: .cpuCountMin)
     try container.encode(cpuCount, forKey: .cpuCount)
     try container.encode(memorySizeMin, forKey: .memorySizeMin)

Sources/tart/VMDirectory+OCI.swift

@@ -142,7 +142,7 @@ extension VMDirectory {
     layers.append(OCIManifestLayer(mediaType: Self.nvramMediaType, size: nvram.count, digest: nvramDigest))
 
     // Craft a stub OCI config for Docker Hub compatibility
-    let ociConfigJSON = try OCIConfig().toJSON()
+    let ociConfigJSON = try OCIConfig(architecture: config.arch, os: config.os).toJSON()
     let ociConfigDigest = try await registry.pushBlob(fromData: ociConfigJSON, chunkSizeMb: chunkSizeMb)
     let manifest = OCIManifest(
             config: OCIManifestConfig(size: ociConfigJSON.count, digest: ociConfigDigest),

Sources/tart/VMDirectory.swift

@@ -20,12 +20,16 @@ struct VMDirectory: Prunable {
     baseURL.appendingPathComponent("nvram.bin")
   }
 
+  var explicitlyPulledMark: URL {
+    baseURL.appendingPathComponent(".explicitly-pulled")
+  }
+
   var name: String {
     baseURL.lastPathComponent
   }
 
   static func temporary() throws -> VMDirectory {
-    let tmpDir = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
+    let tmpDir = try Config().tartTmpDir.appendingPathComponent(UUID().uuidString)
     try FileManager.default.createDirectory(at: tmpDir, withIntermediateDirectories: false)
 
     return VMDirectory(baseURL: tmpDir)
@@ -89,4 +93,12 @@ struct VMDirectory: Prunable {
   func sizeBytes() throws -> Int {
     try configURL.sizeBytes() + diskURL.sizeBytes() + nvramURL.sizeBytes()
   }
+
+  func markExplicitlyPulled() {
+    FileManager.default.createFile(atPath: explicitlyPulledMark.path, contents: nil)
+  }
+
+  func isExplicitlyPulled() -> Bool {
+    FileManager.default.fileExists(atPath: explicitlyPulledMark.path)
+  }
 }

Sources/tart/VMStorageLocal.swift

@@ -1,7 +1,7 @@
 import Foundation
 
 class VMStorageLocal {
-  let baseURL: URL = Config().tartHomeDir.appendingPathComponent("vms", isDirectory: true)
+  let baseURL: URL = try! Config().tartHomeDir.appendingPathComponent("vms", isDirectory: true)
 
   private func vmURL(_ name: String) -> URL {
     baseURL.appendingPathComponent(name, isDirectory: true)
@@ -32,6 +32,10 @@ class VMStorageLocal {
     _ = try FileManager.default.replaceItemAt(vmURL(name), withItemAt: from.baseURL)
   }
 
+  func rename(_ name: String, _ newName: String) throws {
+    _ = try FileManager.default.replaceItemAt(vmURL(newName), withItemAt: vmURL(name))
+  }
+
   func delete(_ name: String) throws {
     try FileManager.default.removeItem(at: vmURL(name))
   }

Sources/tart/VMStorageOCI.swift

@@ -1,12 +1,16 @@
 import Foundation
 
 class VMStorageOCI: PrunableStorage {
-  let baseURL = Config().tartCacheDir.appendingPathComponent("OCIs", isDirectory: true)
+  let baseURL = try! Config().tartCacheDir.appendingPathComponent("OCIs", isDirectory: true)
 
   private func vmURL(_ name: RemoteName) -> URL {
     baseURL.appendingRemoteName(name)
   }
 
+  private func hostDirectoryURL(_ name: RemoteName) -> URL {
+    baseURL.appendingHost(name)
+  }
+
   func exists(_ name: RemoteName) -> Bool {
     VMDirectory(baseURL: vmURL(name)).initialized
   }
@@ -42,6 +46,44 @@ class VMStorageOCI: PrunableStorage {
 
   func delete(_ name: RemoteName) throws {
     try FileManager.default.removeItem(at: vmURL(name))
+    try gc()
+  }
+
+  func gc() throws {
+    var refCounts = Dictionary<URL, UInt>()
+
+    guard let enumerator = FileManager.default.enumerator(at: baseURL,
+            includingPropertiesForKeys: [.isSymbolicLinkKey]) else {
+      return
+    }
+
+    for case let foundURL as URL in enumerator {
+      let isSymlink = try foundURL.resourceValues(forKeys: [.isSymbolicLinkKey]).isSymbolicLink!
+
+      // Perform garbage collection for tag-based images
+      // with broken outgoing references
+      if isSymlink && foundURL == foundURL.resolvingSymlinksInPath() {
+        try FileManager.default.removeItem(at: foundURL)
+        continue
+      }
+
+      let vmDir = VMDirectory(baseURL: foundURL.resolvingSymlinksInPath())
+      if !vmDir.initialized {
+        continue
+      }
+
+      refCounts[vmDir.baseURL] = (refCounts[vmDir.baseURL] ?? 0) + (isSymlink ? 1 : 0)
+    }
+
+    // Perform garbage collection for digest-based images
+    // with no incoming references
+    for (baseURL, incRefCount) in refCounts {
+      let vmDir = VMDirectory(baseURL: baseURL)
+
+      if !vmDir.isExplicitlyPulled() && incRefCount == 0 {
+        try FileManager.default.removeItem(at: baseURL)
+      }
+    }
   }
 
   func list() throws -> [(String, VMDirectory, Bool)] {
@@ -82,22 +124,46 @@ class VMStorageOCI: PrunableStorage {
   func pull(_ name: RemoteName, registry: Registry) async throws {
     defaultLogger.appendNewLine("pulling manifest...")
 
-    let (manifest, _) = try await registry.pullManifest(reference: name.reference.value)
+    let (manifest, manifestData) = try await registry.pullManifest(reference: name.reference.value)
 
-    var digestName = RemoteName(host: name.host, namespace: name.namespace,
-            reference: Reference(digest: try manifest.digest()))
+    let digestName = RemoteName(host: name.host, namespace: name.namespace,
+            reference: Reference(digest: Digest.hash(manifestData)))
+
+    // Ensure that host directory for given RemoteName exists in OCI storage
+    let hostDirectoryURL = hostDirectoryURL(digestName)
+    try FileManager.default.createDirectory(at: hostDirectoryURL, withIntermediateDirectories: true)
+
+    // Acquire a lock on it to prevent concurrent pulls for a single host
+    let lock = try FileLock(lockURL: hostDirectoryURL)
+
+    let sucessfullyLocked = try lock.trylock()
+    if !sucessfullyLocked {
+      print("waiting for lock...")
+      try lock.lock()
+    }
+    defer { try! lock.unlock() }
+
+    if Task.isCancelled {
+      throw CancellationError()
+    }
 
     if !exists(digestName) {
       let tmpVMDir = try VMDirectory.temporary()
 
+      // Lock the temporary VM directory to prevent it's garbage collection
+      let tmpVMDirLock = try FileLock(lockURL: tmpVMDir.baseURL)
+      try tmpVMDirLock.lock()
+
       // Try to reclaim some cache space if we know the VM size in advance
       if let uncompressedDiskSize = manifest.uncompressedDiskSize() {
         let requiredCapacityBytes = UInt64(uncompressedDiskSize + 128 * 1024 * 1024)
 
-        let attrs = try tmpVMDir.baseURL.resourceValues(forKeys: [.volumeAvailableCapacityForImportantUsageKey])
-        let availableCapacityBytes = UInt64(attrs.volumeAvailableCapacityForImportantUsage!)
+        let attrs = try Config().tartCacheDir.resourceValues(forKeys: [.volumeAvailableCapacityForImportantUsageKey, .volumeAvailableCapacityKey])
+        let availableCapacityBytes = max(UInt64(attrs.volumeAvailableCapacityForImportantUsage!), UInt64(attrs.volumeAvailableCapacity!))
 
-        if availableCapacityBytes < requiredCapacityBytes {
+        // There is a suspicious that occasionally capacity is returned as zero which can't be true.
+        // Let's validate to avoid unnecessary pruning.
+        if 0 < availableCapacityBytes && availableCapacityBytes < requiredCapacityBytes {
           try Prune.pruneReclaim(reclaimBytes: requiredCapacityBytes - availableCapacityBytes)
         }
       }
@@ -113,8 +179,12 @@ class VMStorageOCI: PrunableStorage {
     }
 
     if name != digestName {
-      // Overwrite the old symbolic link
+      // Create new or overwrite the old symbolic link
       try link(from: digestName, to: name)
+    } else {
+      // Ensure that images pulled by content digest
+      // are excluded from garbage collection
+      VMDirectory(baseURL: vmURL(name)).markExplicitlyPulled()
     }
   }
 
@@ -124,6 +194,8 @@ class VMStorageOCI: PrunableStorage {
     }
 
     try FileManager.default.createSymbolicLink(at: vmURL(to), withDestinationURL: vmURL(from))
+
+    try gc()
   }
 }
 
@@ -137,4 +209,8 @@ extension URL {
 
     return result
   }
+
+  func appendingHost(_ name: RemoteName) -> URL {
+    self.appendingPathComponent(name.host, isDirectory: true)
+  }
 }

Sources/tart/VNC/ScreenSharingVNC.swift

@@ -10,7 +10,8 @@ class ScreenSharingVNC: VNC {
   }
 
   func waitForURL() async throws -> URL {
-    let ip = try await IP.resolveIP(vmConfig, secondsToWait: 60)
+    let vmMACAddress = MACAddress(fromString: vmConfig.macAddress.string)!
+    let ip = try await IP.resolveIP(vmMACAddress, secondsToWait: 60)
 
     if let ip = ip {
       return URL(string: "vnc://\(ip)")!

Tests/TartTests/FileLockTests.swift

@@ -0,0 +1,34 @@
+import XCTest
+@testable import tart
+
+final class FileLockTests: XCTestCase {
+    func testSimple() throws {
+        // Create a temporary file that will be used as a lock
+        let url = temporaryFile()
+
+        // Make sure this file can be locked and unlocked
+        let lock = try FileLock(lockURL: url)
+        try lock.lock()
+        try lock.unlock()
+    }
+
+    func testDoubleLockResultsInError() throws {
+        // Create a temporary file that will be used as a lock
+        let url = temporaryFile()
+
+        // Create two locks on a same file and ensure one of them fails
+        let firstLock = try FileLock(lockURL: url)
+        try firstLock.lock()
+
+        let secondLock = try! FileLock(lockURL: url)
+        XCTAssertFalse(try secondLock.trylock())
+    }
+
+    private func temporaryFile() -> URL {
+        let url = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent(UUID().uuidString)
+
+        FileManager.default.createFile(atPath: url.path, contents: nil)
+
+        return url
+    }
+}

gon.hcl

@@ -0,0 +1,12 @@
+source = [".build/arm64-apple-macosx/debug/tart"]
+bundle_id = "com.github.cirruslabs.tart"
+
+apple_id {
+  username = "hello@cirruslabs.org"
+  password = "@env:AC_PASSWORD"
+}
+
+sign {
+  application_identity = "Developer ID Application: Cirrus Labs, Inc."
+  entitlements_file = "Resources/tart.entitlements"
+}