Implemented Modbus Serial Client

AMWD.Protocols.Modbus.Serial/Utils/UnsafeNativeMethods.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Runtime.InteropServices;
+#if NETSTANDARD
+using System.Runtime.ConstrainedExecution;
+#endif
+
+namespace AMWD.Protocols.Modbus.Serial.Utils
+{
+	/// <summary>
+	/// Definitions of the unsafe system methods.
+	/// <br/>
+	/// Found on https://stackoverflow.com/a/10388107
+	/// </summary>
+	[System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+	internal static class UnsafeNativeMethods
+	{
+		/// <summary>
+		/// A flag for <see cref="Open(string, uint)"/>.
+		/// </summary>
+		internal const int O_RDWR = 2;
+
+		/// <summary>
+		/// A flag for <see cref="Open(string, uint)"/>.
+		/// </summary>
+		internal const int O_NOCTTY = 256;
+
+		/// <summary>
+		/// A flag for <see cref="IoCtl(SafeUnixHandle, uint, ref SerialRS485)"/>.
+		/// </summary>
+		internal const uint TIOCGRS485 = 0x542E;
+
+		/// <summary>
+		/// A flag for <see cref="IoCtl(SafeUnixHandle, uint, ref SerialRS485)"/>.
+		/// </summary>
+		internal const uint TIOCSRS485 = 0x542F;
+
+		/// <summary>
+		/// Opens a handle to a defined path (serial port).
+		/// </summary>
+		/// <param name="path">The path to open the handle.</param>
+		/// <param name="flag">The flags for the handle.</param>
+		[DllImport("libc", EntryPoint = "open", SetLastError = true)]
+		internal static extern SafeUnixHandle Open(string path, uint flag);
+
+		/// <summary>
+		/// Performs an ioctl request to the open handle.
+		/// </summary>
+		/// <param name="handle">The handle.</param>
+		/// <param name="request">The request.</param>
+		/// <param name="serialRs485">The serial rs485 data structure to use.</param>
+		[DllImport("libc", EntryPoint = "ioctl", SetLastError = true)]
+		internal static extern int IoCtl(SafeUnixHandle handle, uint request, ref SerialRS485 serialRs485);
+
+		/// <summary>
+		/// Closes an open handle.
+		/// </summary>
+		/// <param name="handle">The handle.</param>
+#if NETSTANDARD
+		[ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
+#endif
+		[DllImport("libc", EntryPoint = "close", SetLastError = true)]
+		internal static extern int Close(IntPtr handle);
+
+		/// <summary>
+		/// Converts the given error number (errno) into a readable string.
+		/// </summary>
+		/// <param name="errno">The error number.</param>
+		[DllImport("libc", EntryPoint = "strerror", SetLastError = true, CallingConvention = CallingConvention.Cdecl)]
+		internal static extern IntPtr StrError(int errno);
+	}
+}