From 0b118976171d3c50787e0e28a96b845d687bec65 Mon Sep 17 00:00:00 2001
From: Luke Howard <lukeh@padl.com>
Date: Fri, 12 Jan 2024 06:56:44 +1100
Subject: [PATCH] device spy test

---
 .../IORingDeviceSpy/IORingDeviceSpy.swift     |  69 +++++++++++
 Package.swift                                 |   6 +
 Sources/IORingUtils/Tty.swift                 | 107 ++++++++++++++++++
 3 files changed, 182 insertions(+)
 create mode 100644 Examples/IORingDeviceSpy/IORingDeviceSpy.swift
 create mode 100644 Sources/IORingUtils/Tty.swift

diff --git a/Examples/IORingDeviceSpy/IORingDeviceSpy.swift b/Examples/IORingDeviceSpy/IORingDeviceSpy.swift
new file mode 100644
index 0000000..141af5e
--- /dev/null
+++ b/Examples/IORingDeviceSpy/IORingDeviceSpy.swift
@@ -0,0 +1,69 @@
+//
+// Copyright (c) 2024 PADL Software Pty Ltd
+//
+// 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
+//
+//     http://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 Glibc
+import IORing
+import IORingUtils
+
+@main
+public struct IORingDeviceSpy {
+  private let blockSize: Int
+  private let ring: IORing
+
+  public static func main() async throws {
+    if CommandLine.arguments.count < 2 {
+      print("Usage: \(CommandLine.arguments[0]) [device] <[block_size]>")
+      exit(1)
+    }
+
+    let blockSize: Int
+
+    if CommandLine.arguments.count > 2 {
+      blockSize = Int(CommandLine.arguments[2])!
+    } else {
+      blockSize = 1
+    }
+
+    let spy = try await IORingDeviceSpy(blockSize: blockSize)
+    let device = CommandLine.arguments[1]
+
+    try await spy.spy(device: device)
+  }
+
+  init(blockSize: Int = 1) async throws {
+    ring = IORing.shared
+    self.blockSize = blockSize
+
+    try await ring.registerFixedBuffers(count: 1, size: blockSize)
+  }
+
+  func spy(device: String) async throws {
+    let fd = try FileHandle(fileDescriptor: open(device, O_RDONLY), closeOnDealloc: true)
+
+    try fd.setBlocking(false)
+    if fd.isATty {
+      var tty = try fd.getTty()
+      try tty.setN81(speed: 115_200)
+      try fd.set(tty: tty)
+    }
+
+    repeat {
+      try await ring.readFixed(count: blockSize, bufferIndex: 0, from: fd) {
+        print($0.map { String(format: "%02x", $0) }.joined())
+      }
+    } while !Task.isCancelled
+  }
+}
diff --git a/Package.swift b/Package.swift
index aa18663..ae0bcc0 100644
--- a/Package.swift
+++ b/Package.swift
@@ -147,6 +147,12 @@ let package = Package(
       path: "Examples/IORingUDPServer",
       linkerSettings: [] + ASANLinkerSettings
     ),
+    .executableTarget(
+      name: "IORingDeviceSpy",
+      dependencies: ["IORing", "IORingUtils"],
+      path: "Examples/IORingDeviceSpy",
+      linkerSettings: [] + ASANLinkerSettings
+    ),
   ],
   cLanguageStandard: .c18,
   cxxLanguageStandard: .cxx20
diff --git a/Sources/IORingUtils/Tty.swift b/Sources/IORingUtils/Tty.swift
new file mode 100644
index 0000000..26bef9d
--- /dev/null
+++ b/Sources/IORingUtils/Tty.swift
@@ -0,0 +1,107 @@
+//
+// Copyright (c) 2024 PADL Software Pty Ltd
+//
+// 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
+//
+//     http://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 Glibc
+import IORing
+
+public enum Parity {
+  case none
+  case odd
+  case even
+}
+
+public enum StopBits {
+  case one
+  case two
+}
+
+public enum DataBits {
+  case seven
+  case eight
+}
+
+public extension termios {
+  mutating func setN81(speed: UInt32) throws {
+    try makeRaw()
+    try set(speed: speed)
+    set(parity: .none)
+    set(stopBits: .one)
+    set(dataBits: .eight)
+  }
+
+  mutating func makeRaw() throws {
+    cfmakeraw(&self)
+  }
+
+  mutating func set(speed: UInt32) throws {
+    var tty = self
+    try Errno.throwingErrno {
+      cfsetspeed(&tty, speed)
+    }
+    self = tty
+  }
+
+  mutating func set(parity: Parity) {
+    switch parity {
+    case .none:
+      c_cflag &= ~tcflag_t(PARENB | PARODD)
+    case .odd:
+      c_cflag |= tcflag_t(PARENB | PARODD)
+    case .even:
+      c_cflag |= tcflag_t(PARENB)
+      c_cflag &= ~tcflag_t(PARODD)
+    }
+  }
+
+  mutating func set(stopBits: StopBits) {
+    switch stopBits {
+    case .two:
+      c_cflag |= tcflag_t(CSTOPB)
+    case .one:
+      c_cflag &= ~tcflag_t(CSTOPB)
+    }
+  }
+
+  mutating func set(dataBits: DataBits) {
+    switch dataBits {
+    case .eight:
+      c_cflag |= tcflag_t(CS8)
+    case .seven:
+      c_cflag |= tcflag_t(CS7)
+    }
+  }
+}
+
+public extension FileDescriptorRepresentable {
+  func set(tty: termios) throws {
+    var tty = tty
+    try Errno.throwingErrno {
+      tcsetattr(self.fileDescriptor, TCSANOW, &tty)
+    }
+  }
+
+  func getTty() throws -> termios {
+    var tty = termios()
+    try Errno.throwingErrno {
+      tcgetattr(self.fileDescriptor, &tty)
+    }
+    return tty
+  }
+
+  var isATty: Bool {
+    isatty(fileDescriptor) != 0
+  }
+}