chore: import upstream snapshot with attribution

vminitd/Sources/vmexec/Console.swift

@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+// Copyright © 2025-2026 Apple Inc. and the Containerization project authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//===----------------------------------------------------------------------===//
+
+import FoundationEssentials
+import LCShim
+
+#if canImport(Musl)
+import Musl
+private let _close = Musl.close
+#elseif canImport(Glibc)
+import Glibc
+private let _close = Glibc.close
+#endif
+
+class Console {
+    let master: Int32
+    let slavePath: String
+
+    init() throws {
+        let masterFD = open("/dev/ptmx", O_RDWR | O_NOCTTY | O_CLOEXEC)
+        guard masterFD != -1 else {
+            throw App.Errno(stage: "open_ptmx")
+        }
+
+        guard unlockpt(masterFD) == 0 else {
+            throw App.Errno(stage: "unlockpt")
+        }
+
+        guard let slavePath = ptsname(masterFD) else {
+            throw App.Errno(stage: "ptsname")
+        }
+
+        self.master = masterFD
+        self.slavePath = String(cString: slavePath)
+    }
+
+    func configureStdIO() throws {
+        let path = self.slavePath
+        let slaveFD = open(path, O_RDWR)
+        guard slaveFD != -1 else {
+            throw App.Errno(stage: "open_pts")
+        }
+        defer { _ = _close(slaveFD) }
+
+        for fd: Int32 in 0...2 {
+            guard dup3(slaveFD, fd, 0) != -1 else {
+                throw App.Errno(stage: "dup3")
+            }
+        }
+    }
+
+    func close() throws {
+        guard _close(self.master) == 0 else {
+            throw App.Errno(stage: "close")
+        }
+    }
+}