LinuxContainer: Add ability to close stdin (#201)

This allows the user the ability to raise an EOF for the containers
stdin. Today there's no way to close stdin so something as simple as
"cat" and relying on EOF to move the process forward doesn't work

Sources/Integration/ProcessTests.swift

@@ -74,6 +74,21 @@ extension IntegrationSuite {
         }
     }
 
+    final class StdinBuffer: ReaderStream {
+        let data: Data
+
+        init(data: Data) {
+            self.data = data
+        }
+
+        func stream() -> AsyncStream<Data> {
+            let (stream, cont) = AsyncStream<Data>.makeStream()
+            cont.yield(self.data)
+            cont.finish()
+            return stream
+        }
+    }
+
     func testProcessEchoHi() async throws {
         let id = "test-process-echo-hi"
         let bs = try await bootstrap()
@@ -402,4 +417,36 @@ extension IntegrationSuite {
                 msg: "process should have returned on stdout '\(expected)' != '\(String(data: buffer.data, encoding: .utf8)!)'")
         }
     }
+
+    func testProcessStdin() async throws {
+        let id = "test-container-stdin"
+
+        let bs = try await bootstrap()
+        let container = LinuxContainer(
+            id,
+            rootfs: bs.rootfs,
+            vmm: bs.vmm
+        )
+        container.arguments = ["cat"]
+        container.stdin = StdinBuffer(data: "Hello from test".data(using: .utf8)!)
+
+        let buffer = BufferWriter()
+        container.stdout = buffer
+
+        try await container.create()
+        try await container.start()
+
+        let status = try await container.wait()
+        try await container.stop()
+
+        guard status == 0 else {
+            throw IntegrationError.assert(msg: "process status \(status) != 0")
+        }
+        let expected = "Hello from test"
+
+        guard String(data: buffer.data, encoding: .utf8) == "\(expected)" else {
+            throw IntegrationError.assert(
+                msg: "process should have returned on stdout '\(expected)' != '\(String(data: buffer.data, encoding: .utf8)!)'")
+        }
+    }
 }

Sources/Integration/Suite.swift

@@ -199,6 +199,7 @@ struct IntegrationSuite: AsyncParsableCommand {
             "process false": testProcessFalse,
             "process echo hi": testProcessEchoHi,
             "process user": testProcessUser,
+            "process stdin": testProcessStdin,
             "process home envvar": testProcessHomeEnvvar,
             "process custom home envvar": testProcessCustomHomeEnvvar,
             "process tty ensure TERM": testProcessTtyEnvvar,