internal static T GetProviderParameterStruct <T>(SafeCspHandle provider,
ProviderParameter parameter,
ProviderParameterFlags flags) where T : struct
{
Contract.Requires(provider != null);
Contract.Requires(parameter == ProviderParameter.EnumerateAlgorithms);
// Figure out how big the parameter is
int bufferSize = 0;
IntPtr buffer = IntPtr.Zero;
if (!UnsafeNativeMethods.CryptGetProvParam(provider, parameter, buffer, ref bufferSize, flags))
{
int errorCode = Marshal.GetLastWin32Error();
// NoMoreItems means that we've finished the enumeration we're currently working on, this is
// not a real error, so return an empty structure to mark the end.
if (errorCode == (int)ErrorCode.NoMoreItems)
{
return(new T());
}
else if (errorCode != (int)ErrorCode.MoreData)
{
throw new CryptographicException(errorCode);
}
}
Debug.Assert(Marshal.SizeOf(typeof(T)) <= bufferSize, "Buffer size does not match structure size");
//
// Pull the parameter back and marshal it into the return structure
//
RuntimeHelpers.PrepareConstrainedRegions();
try {
// Allocate in a CER because we could fail between the alloc and the assignment
RuntimeHelpers.PrepareConstrainedRegions();
try { }
finally {
buffer = Marshal.AllocCoTaskMem(bufferSize);
}
if (!UnsafeNativeMethods.CryptGetProvParam(provider, parameter, buffer, ref bufferSize, flags))
{
throw new CryptographicException(Marshal.GetLastWin32Error());
}
return((T)Marshal.PtrToStructure(buffer, typeof(T)));
}
finally {
if (buffer != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(buffer);
}
}
}
public static extern bool CryptGetProvParam(SafeCspHandle hProv,
ProviderParameter dwParam,
IntPtr pbData,
[In, Out] ref int pdwDataLen,
ProviderParameterFlags dwFlags);
internal static T GetProviderParameterStruct <T>(SafeCspHandle provider, ProviderParameter parameter, ProviderParameterFlags flags) where T : struct
{
T local;
int pdwDataLen = 0;
IntPtr zero = IntPtr.Zero;
if (!UnsafeNativeMethods.CryptGetProvParam(provider, parameter, zero, ref pdwDataLen, flags))
{
int hr = Marshal.GetLastWin32Error();
if (hr == 0x103)
{
return(default(T));
}
if (hr != 0xea)
{
throw new CryptographicException(hr);
}
}
RuntimeHelpers.PrepareConstrainedRegions();
try
{
RuntimeHelpers.PrepareConstrainedRegions();
try
{
}
finally
{
zero = Marshal.AllocCoTaskMem(pdwDataLen);
}
if (!UnsafeNativeMethods.CryptGetProvParam(provider, parameter, zero, ref pdwDataLen, flags))
{
throw new CryptographicException(Marshal.GetLastWin32Error());
}
local = (T)Marshal.PtrToStructure(zero, typeof(T));
}
finally
{
if (zero != IntPtr.Zero)
{
Marshal.FreeCoTaskMem(zero);
}
}
return(local);
}
