private static void SendSCSIRequest <TCommand, TData>(UnixFileDescriptor fd, ref TCommand cmd, out TData data) where TCommand : struct where TData : struct
{
var cmdlen = Util.SizeOfStructure <TCommand>();
if (cmdlen > 16)
{
throw new InvalidOperationException("A SCSI command must not exceed 16 bytes in size.");
}
var req = new SCSIRequest {
interface_id = 'S',
dxfer_direction = SCSITransferDirection.FROM_DEV,
timeout = NativeApi.DefaultSCSIRequestTimeOut,
cmd_len = (byte)cmdlen,
mx_sb_len = (byte)64,
dxfer_len = (uint)Util.SizeOfStructure <TData>(),
};
var memlen = (uint)(req.cmd_len + req.mx_sb_len + req.dxfer_len);
var bytes = NativeApi.AllocZero(new UIntPtr(1), new UIntPtr(memlen));
try {
req.cmdp = bytes;
req.sbp = req.cmdp + req.cmd_len;
req.dxferp = req.sbp + req.mx_sb_len;
Marshal.StructureToPtr(cmd, req.cmdp, false);
try {
if (NativeApi.SendSCSIRequest(fd.Value, IOCTL.SG_IO, ref req) != 0)
{
throw new UnixException();
}
if (req.status == SAM.StatusCode.CHECK_CONDITION || req.driver_status == SCSIDriverStatus.DRIVER_SENSE)
{
var response = Marshal.ReadByte(req.sbp) & 0x7f;
switch (response)
{
case 0x70:
case 0x71: // Fixed Format (Current or Deferred)
throw new ScsiException(Util.MarshalPointerToStructure <SPC.FixedSenseData>(req.sbp));
case 0x72:
case 0x73: // Descriptor Format (Current or Deferred)
throw new ScsiException(Util.MarshalPointerToStructure <SPC.DescriptorSenseData>(req.sbp));
default:
throw new IOException($"SCSI CHECK CONDITION: BAD RESPONSE CODE ({response:X2})");
}
}
data = Util.MarshalPointerToStructure <TData>(req.dxferp);
}
finally {
Util.DestroyStructure <TCommand>(req.cmdp);
}
}
finally {
NativeApi.Free(bytes);
}
}
private static extern int SendSCSIRequest(int fd, IOCTL command, ref SCSIRequest request);
