(ExeFile): new class to seek for resources within EXE files.

ArcFormats/ExeFile.cs

@@ -0,0 +1,270 @@
+//! \file       ExeFile.cs
+//! \date       Mon Jan 23 05:12:50 2017
+//! \brief      Win32 EXE file parser/accessor.
+//
+// Copyright (C) 2017 by morkt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Runtime.InteropServices;
+using System.Text;
+using GameRes.Utility;
+
+namespace GameRes.Formats
+{
+    public class ExeFile
+    {
+        ArcView                     m_file;
+        Dictionary<string, Section> m_section_table;
+        Section                     m_overlay;
+
+        public ExeFile (ArcView file)
+        {
+            if (!file.View.AsciiEqual (0, "MZ"))
+                throw new InvalidFormatException ("File is not a valid win32 executable.");
+            m_file = file;
+            Whole = new Section { Offset = 0, Size = (uint)Math.Min (m_file.MaxOffset, uint.MaxValue) };
+        }
+
+        public ArcView.Frame View { get { return m_file.View; } }
+
+        /// <summary>
+        /// Section representing the whole file.
+        /// </summary>
+        public Section Whole { get; private set; }
+
+        /// <summary>
+        /// Dictionary of executable file sections.
+        /// </summary>
+        public IReadOnlyDictionary<string, Section> Sections
+        {
+            get
+            {
+                if (null == m_section_table)
+                    InitSectionTable();
+                return m_section_table;
+            }
+        }
+
+        /// <summary>
+        /// Overlay section of executable file.
+        /// </summary>
+        public Section Overlay
+        {
+            get
+            {
+                if (null == m_section_table)
+                    InitSectionTable();
+                return m_overlay;
+            }
+        }
+
+        /// <summary>
+        /// Structure representing section of executable file in the form of its offset and size.
+        /// </summary>
+        public struct Section
+        {
+            public long Offset;
+            public uint Size;
+        }
+
+        /// <summary>
+        /// Returns true if executable file contains section <paramref name="name"/>.
+        /// </summary>
+        public bool ContainsSection (string name)
+        {
+            return Sections.ContainsKey (name);
+        }
+
+        /// <summary>
+        /// Search for byte sequence within specified section.
+        /// </summary>
+        /// <returns>Offset of byte sequence, if found, -1 otherwise.</returns>
+        public long FindString (Section section, byte[] seq, int step = 1)
+        {
+            if (step <= 0)
+                throw new ArgumentOutOfRangeException ("step", "Search step should be positive integer.");
+            long offset = section.Offset;
+            if (offset < 0 || offset > m_file.MaxOffset)
+                throw new ArgumentOutOfRangeException ("section", "Invalid executable file section specified.");
+            uint seq_length = (uint)seq.Length;
+            if (0 == seq_length || section.Size < seq_length)
+                return -1;
+            long end_offset = Math.Min (m_file.MaxOffset, offset + section.Size);
+            unsafe
+            {
+                while (offset < end_offset)
+                {
+                    uint page_size = (uint)Math.Min (0x10000L, end_offset - offset);
+                    if (page_size < seq_length)
+                        break;
+                    using (var view = m_file.CreateViewAccessor (offset, page_size))
+                    using (var ptr = new ViewPointer (view, offset))
+                    {
+                        byte* page_begin = ptr.Value;
+                        byte* page_end   = page_begin + page_size - seq_length;
+                        byte* p;
+                        for (p = page_begin; p <= page_end; p += step)
+                        {
+                            int i = 0;
+                            while (p[i] == seq[i])
+                            {
+                                if (++i == seq.Length)
+                                    return offset + (p - page_begin);
+                            }
+                        }
+                        offset += p - page_begin;
+                    }
+                }
+            }
+            return -1;
+        }
+
+        public long FindAsciiString (Section section, string seq, int step = 1)
+        {
+            return FindString (section, Encoding.ASCII.GetBytes (seq), step);
+        }
+
+        public long FindSignature (Section section, uint signature, int step = 4)
+        {
+            var bytes = new byte[4];
+            LittleEndian.Pack (signature, bytes, 0);
+            return FindString (section, bytes, step);
+        }
+
+        private void InitSectionTable ()
+        {
+            long pe_offset = m_file.View.ReadUInt32 (0x3C);
+            if (pe_offset >= m_file.MaxOffset-0x58 || !m_file.View.AsciiEqual (pe_offset, "PE\0\0"))
+                throw new InvalidFormatException ("File is not a valid win32 executable.");
+
+            int opt_header = m_file.View.ReadUInt16 (pe_offset+0x14); // SizeOfOptionalHeader
+            long offset = m_file.View.ReadUInt32 (pe_offset+0x54); // SizeOfHeaders
+            long section_table = pe_offset+opt_header+0x18;
+            int count = m_file.View.ReadUInt16 (pe_offset+6); // NumberOfSections
+            var table = new Dictionary<string, Section> (count);
+            if (section_table + 0x28*count < m_file.MaxOffset)
+            {
+                for (int i = 0; i < count; ++i)
+                {
+                    var name = m_file.View.ReadString (section_table, 0x10);
+                    var section = new Section {
+                        Size  = m_file.View.ReadUInt32 (section_table+0x10), 
+                        Offset = m_file.View.ReadUInt32 (section_table+0x14)
+                    };
+                    if (!table.ContainsKey (name))
+                        table.Add (name, section);
+                    if (0 != section.Size)
+                        offset = Math.Max (section.Offset + section.Size, offset);
+                    section_table += 0x28;
+                }
+            }
+            offset = Math.Min ((offset + 0xF) & ~0xFL, m_file.MaxOffset);
+            m_overlay.Offset = offset;
+            m_overlay.Size = (uint)(m_file.MaxOffset - offset);
+            m_section_table = table;
+        }
+
+        /// <summary>
+        /// Helper class for executable file resources access.
+        /// </summary>
+        public sealed class ResourceAccessor : IDisposable
+        {
+            IntPtr      m_exe;
+
+            public ResourceAccessor (string filename)
+            {
+                const uint LOAD_LIBRARY_AS_IMAGE_RESOURCE = 0x20;
+
+                m_exe = NativeMethods.LoadLibraryEx (filename, IntPtr.Zero, LOAD_LIBRARY_AS_IMAGE_RESOURCE);
+                if (IntPtr.Zero == m_exe)
+                    throw new Win32Exception (Marshal.GetLastWin32Error());
+            }
+
+            public byte[] GetResource (string name, string type)
+            {
+                if (m_disposed)
+                    throw new ObjectDisposedException ("Access to disposed ResourceAccessor object failed.");
+                var res = NativeMethods.FindResource (m_exe, name, type);
+                if (IntPtr.Zero == res)
+                    return null;
+                var glob = NativeMethods.LoadResource (m_exe, res);
+                if (IntPtr.Zero == glob)
+                    return null;
+                uint size = NativeMethods.SizeofResource (m_exe, res);
+                var src = NativeMethods.LockResource (glob);
+                if (IntPtr.Zero == src)
+                    return null;
+
+                var dst = new byte[size];
+                Marshal.Copy (src, dst, 0, dst.Length);
+                return dst;
+            }
+
+            #region IDisposable implementation
+            bool m_disposed = false;
+            public void Dispose ()
+            {
+                Dispose (true);
+                GC.SuppressFinalize (this);
+            }
+
+            ~ResourceAccessor ()
+            {
+                Dispose (false);
+            }
+
+            void Dispose (bool disposing)
+            {
+                if (!m_disposed)
+                {
+                    NativeMethods.FreeLibrary (m_exe);
+                    m_disposed = true;
+                }
+            }
+            #endregion
+        }
+    }
+
+    static internal class NativeMethods
+    {
+        [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
+        static internal extern IntPtr LoadLibraryEx (string lpFileName, IntPtr hReservedNull, uint dwFlags);
+
+        [DllImport("kernel32.dll", SetLastError = true)]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        static internal extern bool FreeLibrary (IntPtr hModule);
+
+        [DllImport( "kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
+        static internal extern IntPtr FindResource (IntPtr hModule, string lpName, string lpType);
+
+        [DllImport("Kernel32.dll", SetLastError = true)]
+        static internal extern IntPtr LoadResource (IntPtr hModule, IntPtr hResource);
+
+        [DllImport("Kernel32.dll", SetLastError = true)]
+        static internal extern uint SizeofResource (IntPtr hModule, IntPtr hResource);
+
+        [DllImport("kernel32.dll")]
+        static internal extern IntPtr LockResource (IntPtr hResData);
+    }
+}