From f37a51ef27e572051b0ad5376ebc2d54e9117d91 Mon Sep 17 00:00:00 2001 From: nattthebear Date: Mon, 25 May 2020 07:53:05 -0400 Subject: [PATCH] Rework memory block os abstraction The existing code had a lot of copy paste and things that needed to be done twice to keep both impls in sync. Refactor to use a minimal abstraction layer and keep all other code common --- src/BizHawk.BizInvoke/IMemoryBlockPal.cs | 23 ++ src/BizHawk.BizInvoke/MemoryBlock.cs | 117 +++++++-- src/BizHawk.BizInvoke/MemoryBlockUnix.cs | 133 ---------- src/BizHawk.BizInvoke/MemoryBlockUnixPal.cs | 72 ++++++ src/BizHawk.BizInvoke/MemoryBlockWindows.cs | 238 ------------------ .../MemoryBlockWindowsPal.cs | 164 ++++++++++++ 6 files changed, 356 insertions(+), 391 deletions(-) create mode 100644 src/BizHawk.BizInvoke/IMemoryBlockPal.cs delete mode 100644 src/BizHawk.BizInvoke/MemoryBlockUnix.cs create mode 100644 src/BizHawk.BizInvoke/MemoryBlockUnixPal.cs delete mode 100644 src/BizHawk.BizInvoke/MemoryBlockWindows.cs create mode 100644 src/BizHawk.BizInvoke/MemoryBlockWindowsPal.cs diff --git a/src/BizHawk.BizInvoke/IMemoryBlockPal.cs b/src/BizHawk.BizInvoke/IMemoryBlockPal.cs new file mode 100644 index 0000000000..daebd225a0 --- /dev/null +++ b/src/BizHawk.BizInvoke/IMemoryBlockPal.cs @@ -0,0 +1,23 @@ +using System; + +namespace BizHawk.BizInvoke +{ + /// + /// Platform abstraction layer over mmap like functionality + /// + public interface IMemoryBlockPal : IDisposable + { + /// + /// Map in the memory area at the predetermined address + /// + void PalActivate(); + /// + /// Unmap the memory area + /// + void PalDeactivate(); + /// + /// Change protection on some addresses, guaranteed to be page aligned and in the memory area + /// + void PalProtect(ulong start, ulong size, MemoryBlock.Protection prot); + } +} diff --git a/src/BizHawk.BizInvoke/MemoryBlock.cs b/src/BizHawk.BizInvoke/MemoryBlock.cs index 28d6ab8eea..61be1c4eaa 100644 --- a/src/BizHawk.BizInvoke/MemoryBlock.cs +++ b/src/BizHawk.BizInvoke/MemoryBlock.cs @@ -5,11 +5,11 @@ using BizHawk.Common; namespace BizHawk.BizInvoke { - public abstract class MemoryBlock : IDisposable + public class MemoryBlock : IDisposable { /// allocate bytes starting at a particular address /// is not aligned or is 0 - protected MemoryBlock(ulong start, ulong size) + public MemoryBlock(ulong start, ulong size) { if (!WaterboxUtils.Aligned(start)) throw new ArgumentOutOfRangeException(nameof(start), start, "start address must be aligned"); @@ -19,8 +19,14 @@ namespace BizHawk.BizInvoke Size = WaterboxUtils.AlignUp(size); EndExclusive = Start + Size; _pageData = new Protection[GetPage(EndExclusive - 1) + 1]; + + _pal = OSTailoredCode.IsUnixHost + ? (IMemoryBlockPal)new MemoryBlockUnixPal(Start, Size) + : new MemoryBlockWindowsPal(Start, Size); } + private IMemoryBlockPal _pal; + /// stores last set memory protection value for each page protected readonly Protection[] _pageData; @@ -74,40 +80,111 @@ namespace BizHawk.BizInvoke } /// activate the memory block, swapping it in at the pre-specified address - public abstract void Activate(); + /// is or failed to map file view + public void Activate() + { + if (Active) + throw new InvalidOperationException("Already active"); + _pal.PalActivate(); + ProtectAll(); + Active = true; + } /// deactivate the memory block, removing it from RAM but leaving it immediately available to swap back in - public abstract void Deactivate(); + /// is or failed to unmap file view + public void Deactivate() + { + if (!Active) + throw new InvalidOperationException("Not active"); + _pal.PalDeactivate(); + Active = false; + } /// take a hash of the current full contents of the block, including unreadable areas - public abstract byte[] FullHash(); + /// is or failed to make memory read-only + public byte[] FullHash() + { + if (!Active) + throw new InvalidOperationException("Not active"); + // temporarily switch the entire block to `R` + _pal.PalProtect(Start, Size, Protection.R); + var ret = WaterboxUtils.Hash(GetStream(Start, Size, false)); + ProtectAll(); + return ret; + } - /// set r/w/x protection on a portion of memory. rounded to encompassing pages - public abstract void Protect(ulong start, ulong length, Protection prot); + + /// set r/w/x protection on a portion of memory. rounded to encompassing pagesfailed to protect memory + public void Protect(ulong start, ulong length, Protection prot) + { + if (length == 0) + return; + int pstart = GetPage(start); + int pend = GetPage(start + length - 1); + + for (int i = pstart; i <= pend; i++) + _pageData[i] = prot; // also store the value for later use + + if (Active) // it's legal to Protect() if we're not active; the information is just saved for the next activation + { + var computedStart = WaterboxUtils.AlignDown(start); + var computedEnd = WaterboxUtils.AlignUp(start + length); + var computedLength = computedEnd - computedStart; + + _pal.PalProtect(computedStart, computedLength, prot); + } + } /// restore all recorded protections - protected abstract void ProtectAll(); + private void ProtectAll() + { + int ps = 0; + for (int i = 0; i < _pageData.Length; i++) + { + if (i == _pageData.Length - 1 || _pageData[i] != _pageData[i + 1]) + { + ulong zstart = GetStartAddr(ps); + ulong zend = GetStartAddr(i + 1); + _pal.PalProtect(zstart, zend - zstart, _pageData[i]); + ps = i + 1; + } + } + } /// take a snapshot of the entire memory block's contents, for use in - public abstract void SaveXorSnapshot(); + /// snapshot already taken, is , or failed to make memory read-only + public void SaveXorSnapshot() + { + if (_snapshot != null) + throw new InvalidOperationException("Snapshot already taken"); + if (!Active) + throw new InvalidOperationException("Not active"); - public abstract void Dispose(bool disposing); + // temporarily switch the entire block to `R`: in case some areas are unreadable, we don't want + // that to complicate things + _pal.PalProtect(Start, Size, Protection.R); + + _snapshot = new byte[Size]; + var ds = new MemoryStream(_snapshot, true); + var ss = GetStream(Start, Size, false); + ss.CopyTo(ds); + XorHash = WaterboxUtils.Hash(_snapshot); + + ProtectAll(); + } public void Dispose() { - Dispose(true); - GC.SuppressFinalize(this); - } - - ~MemoryBlock() - { - Dispose(false); + if (_pal != null) + { + _pal.Dispose(); + _pal = null; + } } /// allocate bytes starting at a particular address - public static MemoryBlock Create(ulong start, ulong size) => OSTailoredCode.IsUnixHost - ? (MemoryBlock) new MemoryBlockUnix(start, size) - : new MemoryBlockWindows(start, size); + public static MemoryBlock Create(ulong start, ulong size) => new MemoryBlock(start, size); /// allocate bytes at any address public static MemoryBlock Create(ulong size) => Create(0, size); diff --git a/src/BizHawk.BizInvoke/MemoryBlockUnix.cs b/src/BizHawk.BizInvoke/MemoryBlockUnix.cs deleted file mode 100644 index 36ad113680..0000000000 --- a/src/BizHawk.BizInvoke/MemoryBlockUnix.cs +++ /dev/null @@ -1,133 +0,0 @@ -using System; -using System.IO; - -using static BizHawk.BizInvoke.POSIXLibC; - -namespace BizHawk.BizInvoke -{ - public sealed class MemoryBlockUnix : MemoryBlock - { - /// handle returned by - private int _fd; - - /// - /// failed to get file descriptor (never thrown as is thrown first) - /// always - public MemoryBlockUnix(ulong start, ulong size) : base(start, size) - { - throw new NotImplementedException($"{nameof(MemoryBlockUnix)} ctor"); - #if false - _fd = memfd_create("MemoryBlockUnix", 0); - if (_fd == -1) throw new InvalidOperationException($"{nameof(memfd_create)}() returned -1"); - #endif - } - - /// is or failed to map memory - public override void Activate() - { - if (Active) throw new InvalidOperationException("Already active"); - - var ptr = mmap(Z.US(Start), Z.UU(Size), MemoryProtection.Read | MemoryProtection.Write | MemoryProtection.Execute, 16, _fd, IntPtr.Zero); - if (ptr != Z.US(Start)) throw new InvalidOperationException($"{nameof(mmap)}() returned NULL or the wrong pointer"); - - ProtectAll(); - Active = true; - } - - /// is or failed to unmap memory - public override void Deactivate() - { - if (!Active) throw new InvalidOperationException("Not active"); - - var exitCode = munmap(Z.US(Start), Z.UU(Size)); - if (exitCode != 0) throw new InvalidOperationException($"{nameof(munmap)}() returned {exitCode}"); - - Active = false; - } - - /// is or failed to make memory read-only - public override byte[] FullHash() - { - if (!Active) throw new InvalidOperationException("Not active"); - - // temporarily switch the entire block to `R` - var exitCode = mprotect(Z.US(Start), Z.UU(Size), MemoryProtection.Read); - if (exitCode != 0) throw new InvalidOperationException($"{nameof(mprotect)}() returned {exitCode}!"); - - var ret = WaterboxUtils.Hash(GetStream(Start, Size, false)); - ProtectAll(); - return ret; - } - - /// failed to protect memory - public override void Protect(ulong start, ulong length, Protection prot) - { - if (length == 0) return; - - var pstart = GetPage(start); - var pend = GetPage(start + length - 1); - for (var i = pstart; i <= pend; i++) _pageData[i] = prot; // also store the value for later use - if (!Active) return; // it's legal to call this method if we're not active; the information is just saved for the next activation - - var computedStart = WaterboxUtils.AlignDown(start); - var protEnum = prot.ToMemoryProtection(); - var exitCode = mprotect( - Z.US(computedStart), - Z.UU(WaterboxUtils.AlignUp(start + length) - computedStart), - protEnum - ); - if (exitCode != 0) throw new InvalidOperationException($"{nameof(mprotect)}() returned {exitCode}!"); - } - - protected override void ProtectAll() - { - var ps = 0; - for (var i = 0; i < _pageData.Length; i++) - { - if (i == _pageData.Length - 1 || _pageData[i] != _pageData[i + 1]) - { - var protEnum = _pageData[i].ToMemoryProtection(); - var zstart = GetStartAddr(ps); - var exitCode = mprotect( - Z.US(zstart), - Z.UU(GetStartAddr(i + 1) - zstart), - protEnum - ); - if (exitCode != 0) throw new InvalidOperationException($"{nameof(mprotect)}() returned {exitCode}!"); - - ps = i + 1; - } - } - } - - /// snapshot already taken, is , or failed to make memory read-only - public override void SaveXorSnapshot() - { - if (_snapshot != null) throw new InvalidOperationException("Snapshot already taken"); - if (!Active) throw new InvalidOperationException("Not active"); - - // temporarily switch the entire block to `R`: in case some areas are unreadable, we don't want that to complicate things - var exitCode = mprotect(Z.US(Start), Z.UU(Size), MemoryProtection.Read); - if (exitCode != 0) throw new InvalidOperationException($"{nameof(mprotect)}() returned {exitCode}!"); - - _snapshot = new byte[Size]; - GetStream(Start, Size, false).CopyTo(new MemoryStream(_snapshot, true)); - XorHash = WaterboxUtils.Hash(_snapshot); - ProtectAll(); - } - - public override void Dispose(bool disposing) - { - if (_fd == 0) return; - - if (Active) Deactivate(); - close(_fd); - _fd = -1; - } - - ~MemoryBlockUnix() - { - Dispose(false); - } - } -} diff --git a/src/BizHawk.BizInvoke/MemoryBlockUnixPal.cs b/src/BizHawk.BizInvoke/MemoryBlockUnixPal.cs new file mode 100644 index 0000000000..81cd7f2700 --- /dev/null +++ b/src/BizHawk.BizInvoke/MemoryBlockUnixPal.cs @@ -0,0 +1,72 @@ +using System; +using static BizHawk.BizInvoke.MemoryBlock; +using static BizHawk.BizInvoke.POSIXLibC; + +namespace BizHawk.BizInvoke +{ + public sealed class MemoryBlockUnixPal : IMemoryBlockPal + { + /// handle returned by + private int _fd = -1; + private ulong _start; + private ulong _size; + + /// + /// Reserve bytes to later be swapped in, but do not map them + /// + /// eventual mapped address + /// + /// failed to get file descriptor (never thrown as is thrown first) + /// always + public MemoryBlockUnixPal(ulong start, ulong size) + { + _start = start; + _size = size; + throw new NotImplementedException($"{nameof(MemoryBlockUnixPal)} ctor"); + #if false + _fd = memfd_create("MemoryBlockUnix", 0); + if (_fd == -1) + throw new InvalidOperationException($"{nameof(memfd_create)}() returned -1"); + #endif + } + + public void Dispose() + { + if (_fd == -1) + return; + close(_fd); + _fd = -1; + GC.SuppressFinalize(this); + } + + ~MemoryBlockUnixPal() + { + Dispose(); + } + + public void PalActivate() + { + var ptr = mmap(Z.US(_start), Z.UU(_size), MemoryProtection.Read | MemoryProtection.Write | MemoryProtection.Execute, 16, _fd, IntPtr.Zero); + if (ptr != Z.US(_start)) + throw new InvalidOperationException($"{nameof(mmap)}() returned NULL or the wrong pointer"); + } + + public void PalDeactivate() + { + var exitCode = munmap(Z.US(_start), Z.UU(_size)); + if (exitCode != 0) + throw new InvalidOperationException($"{nameof(munmap)}() returned {exitCode}"); + } + + public void PalProtect(ulong start, ulong size, Protection prot) + { + var exitCode = mprotect( + Z.US(start), + Z.UU(size), + prot.ToMemoryProtection() + ); + if (exitCode != 0) + throw new InvalidOperationException($"{nameof(mprotect)}() returned {exitCode}!"); + } + } +} diff --git a/src/BizHawk.BizInvoke/MemoryBlockWindows.cs b/src/BizHawk.BizInvoke/MemoryBlockWindows.cs deleted file mode 100644 index ba2f6a3591..0000000000 --- a/src/BizHawk.BizInvoke/MemoryBlockWindows.cs +++ /dev/null @@ -1,238 +0,0 @@ -using System; -using System.Runtime.InteropServices; -using System.IO; - -namespace BizHawk.BizInvoke -{ - public sealed class MemoryBlockWindows : MemoryBlock - { - /// - /// handle returned by CreateFileMapping - /// - private IntPtr _handle; - - /// - /// failed to create file mapping - public MemoryBlockWindows(ulong start, ulong size) : base(start, size) - { - _handle = Kernel32.CreateFileMapping( - Kernel32.INVALID_HANDLE_VALUE, - IntPtr.Zero, - Kernel32.FileMapProtection.PageExecuteReadWrite | Kernel32.FileMapProtection.SectionCommit, - (uint)(Size >> 32), - (uint)Size, - null - ); - if (_handle == IntPtr.Zero) throw new InvalidOperationException($"{nameof(Kernel32.CreateFileMapping)}() returned NULL"); - } - - /// is or failed to map file view - public override void Activate() - { - if (Active) - throw new InvalidOperationException("Already active"); - if (Kernel32.MapViewOfFileEx( - _handle, - Kernel32.FileMapAccessType.Read | Kernel32.FileMapAccessType.Write | Kernel32.FileMapAccessType.Execute, - 0, - 0, - Z.UU(Size), - Z.US(Start) - ) != Z.US(Start)) - { - throw new InvalidOperationException($"{nameof(Kernel32.MapViewOfFileEx)}() returned NULL"); - } - ProtectAll(); - Active = true; - } - - /// is or failed to unmap file view - public override void Deactivate() - { - if (!Active) - throw new InvalidOperationException("Not active"); - if (!Kernel32.UnmapViewOfFile(Z.US(Start))) - throw new InvalidOperationException($"{nameof(Kernel32.UnmapViewOfFile)}() returned NULL"); - Active = false; - } - - /// snapshot already taken, is , or failed to make memory read-only - public override void SaveXorSnapshot() - { - if (_snapshot != null) - throw new InvalidOperationException("Snapshot already taken"); - if (!Active) - throw new InvalidOperationException("Not active"); - - // temporarily switch the entire block to `R`: in case some areas are unreadable, we don't want - // that to complicate things - Kernel32.MemoryProtection old; - if (!Kernel32.VirtualProtect(Z.UU(Start), Z.UU(Size), Kernel32.MemoryProtection.READONLY, out old)) - throw new InvalidOperationException($"{nameof(Kernel32.VirtualProtect)}() returned FALSE!"); - - _snapshot = new byte[Size]; - var ds = new MemoryStream(_snapshot, true); - var ss = GetStream(Start, Size, false); - ss.CopyTo(ds); - XorHash = WaterboxUtils.Hash(_snapshot); - - ProtectAll(); - } - - /// is or failed to make memory read-only - public override byte[] FullHash() - { - if (!Active) - throw new InvalidOperationException("Not active"); - // temporarily switch the entire block to `R` - Kernel32.MemoryProtection old; - if (!Kernel32.VirtualProtect(Z.UU(Start), Z.UU(Size), Kernel32.MemoryProtection.READONLY, out old)) - throw new InvalidOperationException($"{nameof(Kernel32.VirtualProtect)}() returned FALSE!"); - var ret = WaterboxUtils.Hash(GetStream(Start, Size, false)); - ProtectAll(); - return ret; - } - - private static Kernel32.MemoryProtection GetKernelMemoryProtectionValue(Protection prot) - { - Kernel32.MemoryProtection p; - switch (prot) - { - case Protection.None: p = Kernel32.MemoryProtection.NOACCESS; break; - case Protection.R: p = Kernel32.MemoryProtection.READONLY; break; - case Protection.RW: p = Kernel32.MemoryProtection.READWRITE; break; - case Protection.RX: p = Kernel32.MemoryProtection.EXECUTE_READ; break; - default: throw new ArgumentOutOfRangeException(nameof(prot)); - } - return p; - } - - protected override void ProtectAll() - { - int ps = 0; - for (int i = 0; i < _pageData.Length; i++) - { - if (i == _pageData.Length - 1 || _pageData[i] != _pageData[i + 1]) - { - var p = GetKernelMemoryProtectionValue(_pageData[i]); - ulong zstart = GetStartAddr(ps); - ulong zend = GetStartAddr(i + 1); - Kernel32.MemoryProtection old; - if (!Kernel32.VirtualProtect(Z.UU(zstart), Z.UU(zend - zstart), p, out old)) - throw new InvalidOperationException($"{nameof(Kernel32.VirtualProtect)}() returned FALSE!"); - ps = i + 1; - } - } - } - - /// failed to protect memory - public override void Protect(ulong start, ulong length, Protection prot) - { - if (length == 0) - return; - int pstart = GetPage(start); - int pend = GetPage(start + length - 1); - - var p = GetKernelMemoryProtectionValue(prot); - for (int i = pstart; i <= pend; i++) - _pageData[i] = prot; // also store the value for later use - - if (Active) // it's legal to Protect() if we're not active; the information is just saved for the next activation - { - var computedStart = WaterboxUtils.AlignDown(start); - var computedEnd = WaterboxUtils.AlignUp(start + length); - var computedLength = computedEnd - computedStart; - - Kernel32.MemoryProtection old; - if (!Kernel32.VirtualProtect(Z.UU(computedStart), - Z.UU(computedLength), p, out old)) - throw new InvalidOperationException($"{nameof(Kernel32.VirtualProtect)}() returned FALSE!"); - } - } - - public override void Dispose(bool disposing) - { - if (_handle != IntPtr.Zero) - { - if (Active) - Deactivate(); - Kernel32.CloseHandle(_handle); - _handle = IntPtr.Zero; - } - } - - ~MemoryBlockWindows() - { - Dispose(false); - } - - private static class Kernel32 - { - [DllImport("kernel32.dll", SetLastError = true)] - public static extern bool VirtualProtect(UIntPtr lpAddress, UIntPtr dwSize, - MemoryProtection flNewProtect, out MemoryProtection lpflOldProtect); - - [Flags] - public enum MemoryProtection : uint - { - EXECUTE = 0x10, - EXECUTE_READ = 0x20, - EXECUTE_READWRITE = 0x40, - EXECUTE_WRITECOPY = 0x80, - NOACCESS = 0x01, - READONLY = 0x02, - READWRITE = 0x04, - WRITECOPY = 0x08, - GUARD_Modifierflag = 0x100, - NOCACHE_Modifierflag = 0x200, - WRITECOMBINE_Modifierflag = 0x400 - } - - [DllImport("kernel32.dll", SetLastError = true)] - public static extern IntPtr CreateFileMapping( - IntPtr hFile, - IntPtr lpFileMappingAttributes, - FileMapProtection flProtect, - uint dwMaximumSizeHigh, - uint dwMaximumSizeLow, - string lpName); - - [Flags] - public enum FileMapProtection : uint - { - PageReadonly = 0x02, - PageReadWrite = 0x04, - PageWriteCopy = 0x08, - PageExecuteRead = 0x20, - PageExecuteReadWrite = 0x40, - SectionCommit = 0x8000000, - SectionImage = 0x1000000, - SectionNoCache = 0x10000000, - SectionReserve = 0x4000000, - } - - [DllImport("kernel32.dll", SetLastError = true)] - public static extern bool CloseHandle(IntPtr hObject); - - [DllImport("kernel32.dll", SetLastError = true)] - public static extern bool UnmapViewOfFile(IntPtr lpBaseAddress); - - [DllImport("kernel32.dll")] - public static extern IntPtr MapViewOfFileEx(IntPtr hFileMappingObject, - FileMapAccessType dwDesiredAccess, uint dwFileOffsetHigh, uint dwFileOffsetLow, - UIntPtr dwNumberOfBytesToMap, IntPtr lpBaseAddress); - - [Flags] - public enum FileMapAccessType : uint - { - Copy = 0x01, - Write = 0x02, - Read = 0x04, - AllAccess = 0x08, - Execute = 0x20, - } - - public static readonly IntPtr INVALID_HANDLE_VALUE = Z.US(0xffffffffffffffff); - } - } -} diff --git a/src/BizHawk.BizInvoke/MemoryBlockWindowsPal.cs b/src/BizHawk.BizInvoke/MemoryBlockWindowsPal.cs new file mode 100644 index 0000000000..894f98a76a --- /dev/null +++ b/src/BizHawk.BizInvoke/MemoryBlockWindowsPal.cs @@ -0,0 +1,164 @@ +using System; +using System.Runtime.InteropServices; +using static BizHawk.BizInvoke.MemoryBlock; + +namespace BizHawk.BizInvoke +{ + internal sealed class MemoryBlockWindowsPal : IMemoryBlockPal + { + /// + /// handle returned by CreateFileMapping + /// + private IntPtr _handle; + private ulong _start; + private ulong _size; + + /// + /// Reserve bytes to later be swapped in, but do not map them + /// + /// eventual mapped address + /// + public MemoryBlockWindowsPal(ulong start, ulong size) + { + _start = start; + _size = size; + _handle = Kernel32.CreateFileMapping( + Kernel32.INVALID_HANDLE_VALUE, + IntPtr.Zero, + Kernel32.FileMapProtection.PageExecuteReadWrite | Kernel32.FileMapProtection.SectionCommit, + (uint)(_size >> 32), + (uint)_size, + null + ); + if (_handle == IntPtr.Zero) + { + throw new InvalidOperationException($"{nameof(Kernel32.CreateFileMapping)}() returned NULL"); + } + } + + public void PalActivate() + { + if (Kernel32.MapViewOfFileEx( + _handle, + Kernel32.FileMapAccessType.Read | Kernel32.FileMapAccessType.Write | Kernel32.FileMapAccessType.Execute, + 0, + 0, + Z.UU(_size), + Z.US(_start) + ) != Z.US(_start)) + { + throw new InvalidOperationException($"{nameof(Kernel32.MapViewOfFileEx)}() returned NULL"); + } + } + + public void PalDeactivate() + { + if (!Kernel32.UnmapViewOfFile(Z.US(_start))) + throw new InvalidOperationException($"{nameof(Kernel32.UnmapViewOfFile)}() returned NULL"); + } + + public void PalProtect(ulong start, ulong size, Protection prot) + { + if (!Kernel32.VirtualProtect(Z.UU(start), Z.UU(size), GetKernelMemoryProtectionValue(prot), out var old)) + throw new InvalidOperationException($"{nameof(Kernel32.VirtualProtect)}() returned FALSE!"); + } + + private static Kernel32.MemoryProtection GetKernelMemoryProtectionValue(Protection prot) + { + Kernel32.MemoryProtection p; + switch (prot) + { + case Protection.None: p = Kernel32.MemoryProtection.NOACCESS; break; + case Protection.R: p = Kernel32.MemoryProtection.READONLY; break; + case Protection.RW: p = Kernel32.MemoryProtection.READWRITE; break; + case Protection.RX: p = Kernel32.MemoryProtection.EXECUTE_READ; break; + default: throw new ArgumentOutOfRangeException(nameof(prot)); + } + return p; + } + + public void Dispose() + { + if (_handle != IntPtr.Zero) + { + Kernel32.CloseHandle(_handle); + _handle = IntPtr.Zero; + GC.SuppressFinalize(this); + } + } + + ~MemoryBlockWindowsPal() + { + Dispose(); + } + + private static class Kernel32 + { + [DllImport("kernel32.dll", SetLastError = true)] + public static extern bool VirtualProtect(UIntPtr lpAddress, UIntPtr dwSize, + MemoryProtection flNewProtect, out MemoryProtection lpflOldProtect); + + [Flags] + public enum MemoryProtection : uint + { + EXECUTE = 0x10, + EXECUTE_READ = 0x20, + EXECUTE_READWRITE = 0x40, + EXECUTE_WRITECOPY = 0x80, + NOACCESS = 0x01, + READONLY = 0x02, + READWRITE = 0x04, + WRITECOPY = 0x08, + GUARD_Modifierflag = 0x100, + NOCACHE_Modifierflag = 0x200, + WRITECOMBINE_Modifierflag = 0x400 + } + + [DllImport("kernel32.dll", SetLastError = true)] + public static extern IntPtr CreateFileMapping( + IntPtr hFile, + IntPtr lpFileMappingAttributes, + FileMapProtection flProtect, + uint dwMaximumSizeHigh, + uint dwMaximumSizeLow, + string lpName); + + [Flags] + public enum FileMapProtection : uint + { + PageReadonly = 0x02, + PageReadWrite = 0x04, + PageWriteCopy = 0x08, + PageExecuteRead = 0x20, + PageExecuteReadWrite = 0x40, + SectionCommit = 0x8000000, + SectionImage = 0x1000000, + SectionNoCache = 0x10000000, + SectionReserve = 0x4000000, + } + + [DllImport("kernel32.dll", SetLastError = true)] + public static extern bool CloseHandle(IntPtr hObject); + + [DllImport("kernel32.dll", SetLastError = true)] + public static extern bool UnmapViewOfFile(IntPtr lpBaseAddress); + + [DllImport("kernel32.dll")] + public static extern IntPtr MapViewOfFileEx(IntPtr hFileMappingObject, + FileMapAccessType dwDesiredAccess, uint dwFileOffsetHigh, uint dwFileOffsetLow, + UIntPtr dwNumberOfBytesToMap, IntPtr lpBaseAddress); + + [Flags] + public enum FileMapAccessType : uint + { + Copy = 0x01, + Write = 0x02, + Read = 0x04, + AllAccess = 0x08, + Execute = 0x20, + } + + public static readonly IntPtr INVALID_HANDLE_VALUE = Z.US(0xffffffffffffffff); + } + } +}