/*
* -----------------------
* Memory Buffer Factories
* -----------------------
*/
/// <summary>
/// Finds an appropriate location where a <see cref="MemoryBuffer"/>;
/// or other memory allocation could be performed.
/// Note: Please see remarks for this function.
/// </summary>
/// <param name = "size" > The space in bytes that the specific <see cref="MemoryBuffer"/> would require to accomodate.</param>
/// <param name="minimumAddress">The minimum absolute address to find a buffer in.</param>
/// <param name="maximumAddress">The maximum absolute address to find a buffer in.</param>
/// <param name="isPrivateBuffer">Defines whether the buffer type created is a shared or private buffer.</param>
/// <remarks>
/// WARNING:
/// Using this in a multithreaded environment can be dangerous, be careful.
/// It is possible to have a race condition on memory allocation.
/// If you want to just allocate memory, please use the provided <see cref="Allocate"/> function instead.
/// </remarks>
public BufferAllocationProperties FindBufferLocation(int size, long minimumAddress, long maximumAddress, bool isPrivateBuffer = false)
{
if (minimumAddress <= 0)
{
throw new ArgumentException("Please do not set the minimum address to 0 or negative. It collides with the return values of Windows API functions" +
"where e.g. 0 is returned on failure but you can also allocate successfully on 0.");
}
int bufferSize = GetBufferSize(size, isPrivateBuffer);
// Search through the buffer cache first.
if (_pageCache != null)
{
for (int x = 0; x < _pageCache.Length; x++)
{
var pointer = GetBufferPointerInPageRange(ref _pageCache[x], bufferSize, (IntPtr)minimumAddress, (IntPtr)maximumAddress);
if (pointer != IntPtr.Zero)
{
// Page cache contains a page that can "work". Check if this page is still valid by running VirtualQuery on it
// and rechecking the new page.
var memoryBasicInformation = new MEMORY_BASIC_INFORMATION();
var result = _virtualQueryFunction(Process.Handle, pointer, ref memoryBasicInformation);
if (result == (UIntPtr)0)
{
throw new Exception("VirtualQuery failed. Result is 0.");
}
var newPointer = GetBufferPointerInPageRange(ref memoryBasicInformation, bufferSize, (IntPtr)minimumAddress, (IntPtr)maximumAddress);
if (newPointer != IntPtr.Zero)
{
return(new BufferAllocationProperties(newPointer, bufferSize));
}
}
}
}
// Not found in cache, get all real pages and try find appropriate spot.
var memoryPages = MemoryPages.GetPages(Process).ToArray();
_pageCache = memoryPages;
for (int x = 0; x < memoryPages.Length; x++)
{
var pointer = GetBufferPointerInPageRange(ref memoryPages[x], bufferSize, (IntPtr)minimumAddress, (IntPtr)maximumAddress);
if (pointer != IntPtr.Zero)
{
return(new BufferAllocationProperties(pointer, bufferSize));
}
}
throw new Exception($"Unable to find memory location to fit MemoryBuffer of size {size} ({bufferSize}) between {minimumAddress.ToString("X")} and {maximumAddress.ToString("X")}.");
}
/*
* -----------------------
* Memory Buffer Factories
* -----------------------
*/
/// <summary>
/// Finds an appropriate location where a <see cref="MemoryBuffer"/>;
/// or other memory allocation could be performed.
/// Note: Please see remarks for this function.
/// </summary>
/// <param name = "size" > The space in bytes that the specific <see cref="MemoryBuffer"/> would require to accomodate.</param>
/// <param name="minimumAddress">The minimum absolute address to find a buffer in.</param>
/// <param name="maximumAddress">The maximum absolute address to find a buffer in.</param>
/// <param name="isPrivateBuffer">Defines whether the buffer type created is a shared or private buffer.</param>
/// <remarks>
/// WARNING:
/// Using this in a multithreaded environment can be dangerous, be careful.
/// It is possible to have a race condition on memory allocation.
/// If you want to just allocate memory, please use the provided <see cref="Allocate"/> function instead.
/// </remarks>
public BufferAllocationProperties FindBufferLocation(int size, nuint minimumAddress, nuint maximumAddress, bool isPrivateBuffer = false)
{
if (minimumAddress <= 0)
{
throw new ArgumentException("Please do not set the minimum address to 0 or negative. It collides with the return values of Windows API functions" +
"where e.g. 0 is returned on failure but you can also allocate successfully on 0.");
}
int bufferSize = GetBufferSize(size, isPrivateBuffer);
// Not found in cache, get all real pages and try find appropriate spot.
var memoryPages = MemoryPages.GetPages(Process);
for (int x = 0; x < memoryPages.Count; x++)
{
var pointer = GetBufferPointerInPageRange(memoryPages[x], bufferSize, minimumAddress, maximumAddress);
if (pointer != 0)
{
return(new BufferAllocationProperties(pointer, bufferSize));
}
}
throw new Exception($"Unable to find memory location to fit MemoryBuffer of size {size} ({bufferSize}) between {minimumAddress} and {maximumAddress}.");
}
