reactos/drivers/base/kdgdb/gdb_receive.c

   1 /*
   2  * COPYRIGHT:       GPL, see COPYING in the top level directory
   3  * PROJECT:         ReactOS kernel
   4  * FILE:            drivers/base/kddll/gdb_receive.c
   5  * PURPOSE:         Base functions for the kernel debugger.
   6  */
   7
   8 #include "kdgdb.h"
   9
  10 /* GLOBALS ********************************************************************/
  11 CHAR gdb_input[0x1000];
  12
  13 /* GLOBAL FUNCTIONS ***********************************************************/
  14 char
  15 hex_value(char ch)
  16 {
  17     if ((ch >= '0') && (ch <= '9'))
  18         return (ch - '0');
  19
  20     if ((ch >= 'a') && (ch <= 'f'))
  21         return (ch - 'a' + 10);
  22
  23     if ((ch >= 'A') && (ch <= 'F'))
  24         return (ch - 'A' + 10);
  25
  26     return -1;
  27 }
  28
  29 KDSTATUS
  30 NTAPI
  31 gdb_receive_packet(_Inout_ PKD_CONTEXT KdContext)
  32 {
  33     char* ByteBuffer = gdb_input;
  34     UCHAR Byte;
  35     KDSTATUS Status;
  36     CHAR CheckSum = 0, ReceivedCheckSum;
  37
  38     do
  39     {
  40         Status = KdpReceiveByte(&Byte);
  41         if (Status != KdPacketReceived)
  42             return Status;
  43         if (Byte == 0x03)
  44         {
  45             KdContext->KdpControlCPending = TRUE;
  46             return KdPacketNeedsResend;
  47         }
  48     } while (Byte != '$');
  49
  50     while (TRUE)
  51     {
  52         /* Try to get a byte from the port */
  53         Status = KdpReceiveByte(&Byte);
  54         if (Status != KdPacketReceived)
  55             return Status;
  56
  57         if (Byte == '#')
  58         {
  59             *ByteBuffer = '\0';
  60             break;
  61         }
  62
  63         *ByteBuffer++ = Byte;
  64         CheckSum += (CHAR)Byte;
  65     }
  66
  67     /* Get Check sum (two bytes) */
  68     Status = KdpReceiveByte(&Byte);
  69     if (Status != KdPacketReceived)
  70         goto end;
  71     ReceivedCheckSum = hex_value(Byte) << 4;;
  72
  73     Status = KdpReceiveByte(&Byte);
  74     if (Status != KdPacketReceived)
  75         goto end;
  76     ReceivedCheckSum += hex_value(Byte);
  77
  78 end:
  79     if (ReceivedCheckSum != CheckSum)
  80     {
  81         /* Do not acknowledge to GDB */
  82         KdpSendByte('-');
  83         return KdPacketNeedsResend;
  84     }
  85
  86     /* Acknowledge */
  87     KdpSendByte('+');
  88
  89     return KdPacketReceived;
  90 }