Fix control socket paths with special characters (#1328)

Sources/tart/Commands/Exec.swift

@@ -45,7 +45,7 @@ struct Exec: AsyncParsableCommand {
     //
     // [1]: https://blog.8-p.info/en/2020/06/11/unix-domain-socket-length/
     if let baseURL = vmDir.controlSocketURL.baseURL {
-      FileManager.default.changeCurrentDirectoryPath(baseURL.path())
+      FileManager.default.changeCurrentDirectoryPath(baseURL.absoluteURL.path(percentEncoded: false))
     }
 
     // Switch controlling terminal into raw mode when remote pseudo-terminal is requested

Sources/tart/Commands/IP.swift

@@ -73,7 +73,7 @@ struct IP: AsyncParsableCommand {
         //
         // [1]: https://blog.8-p.info/en/2020/06/11/unix-domain-socket-length/
         if let baseURL = controlSocketURL.baseURL {
-          FileManager.default.changeCurrentDirectoryPath(baseURL.path())
+          FileManager.default.changeCurrentDirectoryPath(baseURL.absoluteURL.path(percentEncoded: false))
         }
 
         if let ip = try await AgentResolver.ResolveIP(controlSocketURL.relativePath) {

Sources/tart/ControlSocket.swift

@@ -22,14 +22,14 @@ class ControlSocket {
 
     // Remove control socket file from previous "tart run" invocations,
     // if any, otherwise we may get the "address already in use" error
-    try? FileManager.default.removeItem(atPath: controlSocketURL.path())
+    try? FileManager.default.removeItem(at: controlSocketURL)
 
     // Change the current working directory to a VM's base directory
     // to work around Unix domain socket 104 byte limitation [1]
     //
     // [1]: https://blog.8-p.info/en/2020/06/11/unix-domain-socket-length/
     if let baseURL = controlSocketURL.baseURL {
-      FileManager.default.changeCurrentDirectoryPath(baseURL.path())
+      FileManager.default.changeCurrentDirectoryPath(baseURL.absoluteURL.path(percentEncoded: false))
     }
 
     do {

Tests/TartTests/ControlSocketTests.swift

@@ -1,6 +1,10 @@
+import NIO
 import XCTest
 @testable import tart
 
+// Avoid NSObject.bind and Tart's Darwin type shadowing the system function.
+private let bindTestSocket = bind
+
 @available(macOS 14, *)
 final class ControlSocketTests: XCTestCase {
   func testInitializerCreatesControlSocketBeforeReturning() async throws {
@@ -44,6 +48,43 @@ final class ControlSocketTests: XCTestCase {
     }
   }
 
+  func testInitializerReplacesStaleSocketInLongEncodedPath() async throws {
+    let temporaryDirectory = try makeTemporaryDirectory()
+    let originalDirectory = FileManager.default.currentDirectoryPath
+    defer {
+      FileManager.default.changeCurrentDirectoryPath(originalDirectory)
+      try? FileManager.default.removeItem(at: temporaryDirectory)
+    }
+
+    let vmDirectory = temporaryDirectory.appendingPathComponent(
+      "Tart Home %# 虚拟机 " + String(repeating: "v", count: 104), isDirectory: true
+    )
+    try FileManager.default.createDirectory(at: vmDirectory, withIntermediateDirectories: false)
+    let socketURL = URL(fileURLWithPath: "control.sock", relativeTo: vmDirectory)
+    XCTAssertGreaterThan(socketURL.path.utf8.count, 104)
+
+    // Closing a POSIX socket leaves its path behind, as exiting "tart run" does.
+    XCTAssertTrue(FileManager.default.changeCurrentDirectoryPath(vmDirectory.path))
+    let expectedDirectory = FileManager.default.currentDirectoryPath
+    let address = try SocketAddress(unixDomainSocketPath: "control.sock")
+    let descriptor = socket(AF_UNIX, SOCK_STREAM, 0)
+    XCTAssertGreaterThanOrEqual(descriptor, 0)
+    XCTAssertEqual(address.withSockAddr { bindTestSocket(descriptor, $0, socklen_t($1)) }, 0)
+    XCTAssertEqual(close(descriptor), 0)
+    XCTAssertTrue(FileManager.default.changeCurrentDirectoryPath(originalDirectory))
+
+    var controlSocket: ControlSocket? = try await ControlSocket(socketURL)
+    let eventLoopGroup = try XCTUnwrap(controlSocket?.eventLoopGroup)
+    do {
+      let serverChannel = try XCTUnwrap(controlSocket?.serverChannel)
+      XCTAssertEqual(FileManager.default.currentDirectoryPath, expectedDirectory)
+      XCTAssertTrue(FileManager.default.fileExists(atPath: socketURL.path))
+      try await serverChannel.executeThenClose { _ in }
+    }
+    controlSocket = nil
+    try await eventLoopGroup.shutdownGracefully()
+  }
+
   private func makeTemporaryDirectory() throws -> URL {
     let directory = FileManager.default.temporaryDirectory.appendingPathComponent(
       UUID().uuidString,