/// <summary>
/// Query a variable buffer from the object.
/// </summary>
/// <param name="info_class">The information class to query.</param>
/// <param name="init_buffer">A buffer to initialize the initial query. Can be null.</param>
/// <param name="throw_on_error">True to throw on error.</param>
/// <returns>The result of the query.</returns>
/// <exception cref="NtException">Thrown on error.</exception>
public virtual NtResult <SafeHGlobalBuffer> QueryRawBuffer(Q info_class, byte[] init_buffer, bool throw_on_error)
{
NtStatus status;
int return_length;
// First try base size before trying to reallocate.
using (var buffer = init_buffer.ToBuffer())
{
status = QueryInformation(info_class, buffer, out return_length);
if (status.IsSuccess())
{
return(status.CreateResult(false, () => buffer.Detach(return_length)));
}
}
if (!IsInvalidBufferStatus(status))
{
return(status.CreateResultFromError <SafeHGlobalBuffer>(throw_on_error));
}
// If the function returned a length then trust it.
if (return_length > 0 && GetTrustReturnLength(info_class))
{
using (var buffer = new SafeHGlobalBuffer(return_length))
{
return(QueryInformation(info_class, buffer, out return_length).CreateResult(throw_on_error, () => buffer.Detach(return_length)));
}
}
// Function length can't be trusted, we'll need to brute force it.
return_length = 256;
int max_length = GetMaximumBruteForceLength(info_class);
while (return_length <= max_length)
{
using (var buffer = new SafeHGlobalBuffer(return_length))
{
status = QueryInformation(info_class, buffer, out int dummy_length);
if (status.IsSuccess())
{
if (dummy_length > 0 && dummy_length < return_length)
{
return_length = dummy_length;
}
return(status.CreateResult(throw_on_error, () => buffer.Detach(return_length)));
}
else if (!IsInvalidBufferStatus(status))
{
return(status.CreateResultFromError <SafeHGlobalBuffer>(throw_on_error));
}
return_length *= 2;
}
}
return(NtStatus.STATUS_BUFFER_TOO_SMALL.CreateResultFromError <SafeHGlobalBuffer>(throw_on_error));
}
private NtResult <SafeHGlobalBuffer> CreateRelativeSecurityDescriptor(bool throw_on_error)
{
using (var sd_buffer = CreateAbsoluteSecurityDescriptor(throw_on_error))
{
if (!sd_buffer.IsSuccess)
{
return(sd_buffer);
}
int total_length = 0;
NtStatus status = NtRtl.RtlAbsoluteToSelfRelativeSD(sd_buffer.Result, SafeHGlobalBuffer.Null, ref total_length);
if (status != NtStatus.STATUS_BUFFER_TOO_SMALL)
{
return(status.CreateResultFromError <SafeHGlobalBuffer>(throw_on_error));
}
using (var relative_sd = new SafeHGlobalBuffer(total_length))
{
return(NtRtl.RtlAbsoluteToSelfRelativeSD(sd_buffer.Result, relative_sd, ref total_length)
.CreateResult(throw_on_error, () => relative_sd.Detach()));
}
}
}