Abstract GameProcess

Dalamud.Bootstrap/GameProcess.cs

@@ -0,0 +1,83 @@
+using System;
+using Dalamud.Bootstrap.SqexArg;
+using Dalamud.Bootstrap.Windows;
+
+namespace Dalamud.Bootstrap
+{
+    internal sealed class GameProcess : IDisposable
+    {
+        private Process m_process;
+
+        public GameProcess(Process process)
+        {
+            m_process = process;
+        }
+
+        public static GameProcess Open(uint pid)
+        {
+            const PROCESS_ACCESS_RIGHT access = PROCESS_ACCESS_RIGHT.PROCESS_VM_OPERATION
+                | PROCESS_ACCESS_RIGHT.PROCESS_VM_READ
+                // | PROCESS_ACCESS_RIGHT.PROCESS_VM_WRITE // we don't need it for now
+                | PROCESS_ACCESS_RIGHT.PROCESS_QUERY_LIMITED_INFORMATION
+                | PROCESS_ACCESS_RIGHT.PROCESS_QUERY_INFORMATION
+                | PROCESS_ACCESS_RIGHT.PROCESS_CREATE_THREAD
+                | PROCESS_ACCESS_RIGHT.PROCESS_TERMINATE;
+
+            // TODO: unfuck VM_WRITE
+
+            var process = Process.Open(pid, access);
+
+            return new GameProcess(process);
+        }
+
+        public void Dispose()
+        {
+            m_process?.Dispose();
+            m_process = null!;
+        }
+
+        /// <summary>
+        /// Recovers a key used in encrypting process arguments.
+        /// </summary>
+        /// <returns>A key recovered from the time when the process was created.</returns>
+        /// <remarks>
+        /// This is possible because the key to encrypt arguments is just a high nibble value from GetTickCount() at the time when the process was created.
+        /// (Thanks Wintermute!)
+        /// </remarks>
+        private uint GetArgumentEncryptionKey()
+        {
+            var createdTime = m_process.GetCreationTime();
+
+            // Get current tick
+            var currentDt = DateTime.Now;
+            var currentTick = Environment.TickCount;
+
+            // We know that GetTickCount() is just a system uptime in milliseconds.
+            var delta = currentDt - createdTime;
+            var createdTick = (uint)currentTick - (uint)delta.TotalMilliseconds;
+
+            // only the high nibble is used.
+            return createdTick & 0xFFFF_0000;
+        }
+
+        public ArgumentBuilder ReadArguments()
+        {
+            var arguments = m_process.ReadArguments();
+
+            if (arguments.Length < 2)
+            {
+                throw new BootstrapException($"Process id {m_process.GetPid()} have no arguments to parse.");
+            }
+
+            var argument = arguments[1];
+
+            if (EncryptedArgument.TryParse(argument, out var encryptedArgument))
+            {
+                var key = GetArgumentEncryptionKey();
+                argument = encryptedArgument.Decrypt(key);
+            }
+
+            return ArgumentBuilder.Parse(argument);
+        }
+    }
+}