Imported Upstream version 6.4.0.137

Former-commit-id: 943baa9f16a098c33e129777827f3a9d20da00d6

mcs/class/System.Private.CoreLib/System/Environment.Unix.cs

@@ -0,0 +1,44 @@
+using System.Collections;
+using System.Globalization;
+using System.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using Mono;
+
+namespace System
+{
+	partial class Environment
+	{
+		static string GetEnvironmentVariableCore (string variable)
+		{
+			using (var h = RuntimeMarshal.MarshalString (variable)) {
+				return internalGetEnvironmentVariable_native (h.Value);
+			}
+		}
+
+		[MethodImplAttribute (MethodImplOptions.InternalCall)]
+		extern static string internalGetEnvironmentVariable_native (IntPtr variable);
+
+		[MethodImplAttribute (MethodImplOptions.InternalCall)]
+		private extern static string [] GetEnvironmentVariableNames ();
+
+		public static IDictionary GetEnvironmentVariables ()
+		{
+			Hashtable vars = new Hashtable ();
+			foreach (string name in GetEnvironmentVariableNames ()) {
+				vars [name] = GetEnvironmentVariableCore (name);
+			}
+			return vars;
+		}
+
+		static unsafe void SetEnvironmentVariableCore (string variable, string value)
+		{
+			fixed (char *fixed_variable = variable)
+			fixed (char *fixed_value = value)
+				InternalSetEnvironmentVariable (fixed_variable, variable.Length, fixed_value, value?.Length ?? 0);
+		}
+
+		[MethodImplAttribute (MethodImplOptions.InternalCall)]
+		static extern unsafe void InternalSetEnvironmentVariable (char *variable, int variable_length, char *value, int value_length);
+	}
+}