gdbserve.c

这个是LINUX下的GDB调度工具的源码

  if (remote_debug)
    {
      ConsolePrintf ("vector=%d: %s, pc=%08x, thread=%08x\r\n",
		     frame->ExceptionNumber,
		     frame->ExceptionDescription,
		     frame->ExceptionPC,
		     GetThreadID ());
    }

  switch (frame->ExceptionNumber)
    {
    case START_NLM_EVENT:
      /* If the NLM just started, we record the module load information
	 and the thread ID, and set a breakpoint at the first instruction
	 in the program.  */

      ldinfo = ((struct DBG_LoadDefinitionStructure *)
		frame->ExceptionErrorCode);
      memcpy (first_insn, ldinfo->LDInitializationProcedure,
	      BREAKPOINT_SIZE);
      memcpy (ldinfo->LDInitializationProcedure, breakpoint_insn,
	      BREAKPOINT_SIZE);
      flush_i_cache ();
      return RETURN_TO_PROGRAM;

    case ENTER_DEBUGGER_EVENT:
    case KEYBOARD_BREAK_EVENT:
      /* Pass some events on to the next debugger, in case it will handle
	 them.  */
      return RETURN_TO_NEXT_DEBUGGER;

    case 3:			/* Breakpoint */
      /* After we've reached the initial breakpoint, reset it.  */
      if (frame->ExceptionPC - DECR_PC_AFTER_BREAK == (LONG) ldinfo->LDInitializationProcedure
	  && memcmp (ldinfo->LDInitializationProcedure, breakpoint_insn,
		     BREAKPOINT_SIZE) == 0)
	{
	  memcpy (ldinfo->LDInitializationProcedure, first_insn,
		  BREAKPOINT_SIZE);
	  frame->ExceptionPC -= DECR_PC_AFTER_BREAK;
	  flush_i_cache ();
	}
      /* Normal breakpoints end up here */
      do_status (remcomOutBuffer, frame);
      break;

    default:
      /* At the moment, we don't care about most of the unusual NetWare
	 exceptions.  */
      if (frame->ExceptionNumber > 31)
	return RETURN_TO_PROGRAM;

      /* Most machine level exceptions end up here */
      do_status (remcomOutBuffer, frame);
      break;

    case 11:			/* Segment not present */
    case 13:			/* General protection */
    case 14:			/* Page fault */
      /* If we get a GP fault, and mem_may_fault is set, and the
	 instruction pointer is near set_char or get_char, then we caused
	 the fault ourselves accessing an illegal memory location.  */
      if (mem_may_fault
	  && ((frame->ExceptionPC >= (long) &set_char
	       && frame->ExceptionPC < (long) &set_char + 50)
	      || (frame->ExceptionPC >= (long) &get_char
		  && frame->ExceptionPC < (long) &get_char + 50)))
	{
	  mem_err = 1;
	  /* Point the instruction pointer at an assembly language stub
	     which just returns from the function.  */

	  frame->ExceptionPC += 4; /* Skip the load or store */

	  /* Keep going.  This will act as though it returned from
	     set_char or get_char.  The calling routine will check
	     mem_err, and do the right thing.  */
	  return RETURN_TO_PROGRAM;
	}
      /* Random mem fault, report it */
      do_status (remcomOutBuffer, frame);
      break;

    case TERMINATE_NLM_EVENT:
      /* There is no way to get the exit status.  */
      sprintf (remcomOutBuffer, "W%02x", 0);
      break;			/* We generate our own status */
    }

  /* FIXME: How do we know that this exception has anything to do with
     the program we are debugging?  We can check whether the PC is in
     the range of the module we are debugging, but that doesn't help
     much since an error could occur in a library routine.  */

  clear_step_traps (frame);

  if (! putpacket(remcomOutBuffer))
    return RETURN_TO_NEXT_DEBUGGER;

  if (frame->ExceptionNumber == TERMINATE_NLM_EVENT)
    {
      ResumeThread (mainthread);
      return RETURN_TO_PROGRAM;
    }

  while (1)
    {
      error = 0;
      remcomOutBuffer[0] = 0;
      if (! getpacket (remcomInBuffer))
	return RETURN_TO_NEXT_DEBUGGER;
      switch (remcomInBuffer[0])
	{
	case '?':
	  do_status (remcomOutBuffer, frame);
	  break;
	case 'd':
	  remote_debug = !(remote_debug); /* toggle debug flag */
	  break;
	case 'g':
	  /* return the value of the CPU registers */
	  frame_to_registers (frame, remcomOutBuffer);
	  break;
	case 'G':
	  /* set the value of the CPU registers - return OK */
	  registers_to_frame (&remcomInBuffer[1], frame);
	  strcpy(remcomOutBuffer,"OK");
	  break;

	case 'm':
	  /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
	  /* TRY TO READ %x,%x.  IF SUCCEED, SET PTR = 0 */
	  ptr = &remcomInBuffer[1];
	  if (hexToInt(&ptr,&addr))
	    if (*(ptr++) == ',')
	      if (hexToInt(&ptr,&length))
		{
		  ptr = 0;
		  mem_err = 0;
		  mem2hex((char*) addr, remcomOutBuffer, length, 1);
		  if (mem_err)
		    {
		      strcpy (remcomOutBuffer, "E03");
		      debug_error ("memory fault");
		    }
		}

	  if (ptr)
	    {
	      strcpy(remcomOutBuffer,"E01");
	      debug_error("malformed read memory command: %s",remcomInBuffer);
	    }
	  break;

	case 'M':
	  /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */
	  /* TRY TO READ '%x,%x:'.  IF SUCCEED, SET PTR = 0 */
	  ptr = &remcomInBuffer[1];
	  if (hexToInt(&ptr,&addr))
	    if (*(ptr++) == ',')
	      if (hexToInt(&ptr,&length))
		if (*(ptr++) == ':')
		  {
		    mem_err = 0;
		    hex2mem(ptr, (char*) addr, length, 1);

		    if (mem_err)
		      {
			strcpy (remcomOutBuffer, "E03");
			debug_error ("memory fault");
		      }
		    else
		      {
			strcpy(remcomOutBuffer,"OK");
		      }

		    ptr = 0;
		  }
	  if (ptr)
	    {
	      strcpy(remcomOutBuffer,"E02");
	      debug_error("malformed write memory command: %s",remcomInBuffer);
	    }
	  break;

	case 'c':
	case 's':
	  /* cAA..AA    Continue at address AA..AA(optional) */
	  /* sAA..AA   Step one instruction from AA..AA(optional) */
	  /* try to read optional parameter, pc unchanged if no parm */
	  ptr = &remcomInBuffer[1];
	  if (hexToInt(&ptr,&addr))
	    {
/*	      registers[PC_REGNUM].lo = addr;*/
	      fprintf (stderr, "Setting PC to 0x%x\n", addr);
	      while (1);
	    }

	  if (remcomInBuffer[0] == 's')
	    set_step_traps (frame);

	  flush_i_cache ();
	  return RETURN_TO_PROGRAM;

	case 'k':
	  /* kill the program */
	  KillMe (ldinfo);
	  ResumeThread (mainthread);
	  return RETURN_TO_PROGRAM;

	case 'q':		/* Query message */
	  if (strcmp (&remcomInBuffer[1], "Offsets") == 0)
	    {
	      sprintf (remcomOutBuffer, "Text=%x;Data=%x;Bss=%x",
		       ldinfo->LDCodeImageOffset,
		       ldinfo->LDDataImageOffset,
		       ldinfo->LDDataImageOffset + ldinfo->LDDataImageLength);
	    }
	  else
	    sprintf (remcomOutBuffer, "E04, Unknown query %s", &remcomInBuffer[1]);
	  break;
	}

      /* reply to the request */
      if (! putpacket(remcomOutBuffer))
	return RETURN_TO_NEXT_DEBUGGER;
    }
}

char *progname;

struct bitRate {
  BYTE bitRate;
  const char *bitRateString;
};

struct bitRate bitRateTable[] = 
{
  { AIO_BAUD_50    ,      "50" },
  { AIO_BAUD_75    ,      "75" },
  { AIO_BAUD_110   ,     "110" },
  { AIO_BAUD_134p5 ,   "134.5" },
  { AIO_BAUD_150   ,     "150" },
  { AIO_BAUD_300   ,     "300" },
  { AIO_BAUD_600   ,     "600" },
  { AIO_BAUD_1200  ,    "1200" },
  { AIO_BAUD_1800  ,    "1800" },
  { AIO_BAUD_2000  ,    "2000" },
  { AIO_BAUD_2400  ,    "2400" },
  { AIO_BAUD_3600  ,    "3600" },
  { AIO_BAUD_4800  ,    "4800" },
  { AIO_BAUD_7200  ,    "7200" },
  { AIO_BAUD_9600  ,    "9600" },
  { AIO_BAUD_19200 ,   "19200" },
  { AIO_BAUD_38400 ,   "38400" },
  { AIO_BAUD_57600 ,   "57600" },
  { AIO_BAUD_115200,  "115200" },
  { -1, NULL }
};

char dataBitsTable[] = "5678";

char *stopBitsTable[] = { "1", "1.5", "2" };

char parity[] = "NOEMS";

/* Start up.  The main thread opens the named serial I/O port, loads
   the named NLM module and then goes to sleep.  The serial I/O port
   is named as a board number and a port number.  It would be more DOS
   like to provide a menu of available serial ports, but I don't want
   to have to figure out how to do that.  */

int
main (int argc, char **argv)
{
  int hardware, board, port;
  BYTE bitRate;
  BYTE dataBits;
  BYTE stopBits;
  BYTE parityMode;
  LONG err;
  struct debuggerStructure s;
  int cmdindx;
  char *cmdlin;
  int i;

  /* set progname */
  progname = "gdbserve";

  /* set default serial line */
  hardware = -1;
  board = 0;
  port = 0;

  /* set default serial line characteristics */
  bitRate  = AIO_BAUD_9600;
  dataBits = AIO_DATA_BITS_8;
  stopBits = AIO_STOP_BITS_1;
  parityMode = AIO_PARITY_NONE;

  cmdindx = 0;
  for (argc--, argv++; *argv; argc--, argv++) 
    {
      char *bp;
      char *ep;

      if (strnicmp(*argv, "BAUD=", 5) == 0) 
	{
	  struct bitRate *brp;

	  bp = *argv + 5;
	  for (brp = bitRateTable; brp->bitRate != (BYTE) -1; brp++) 
	    {
	      if (strcmp(brp->bitRateString, bp) == 0) 
		{
		  bitRate = brp->bitRate;
		  break;
		}
	    }

	  if (brp->bitRateString == NULL) 
	    {
	      fprintf(stderr, "%s: %s: unknown or unsupported bit rate",
		      progname, bp);
	      exit (1);
	    }
	}
      else if (strnicmp(*argv, "BOARD=", 6) == 0) 
        {
	  bp = *argv + 6;
	  board = strtol (bp, &ep, 0);
	  if (ep == bp || *ep != '\0') 
	    {
	      fprintf (stderr, "%s: %s: expected integer argument\n", 
		       progname, bp);
	      exit(1);
	    }
	}
#if 1				/* FIXME: this option has been depricated */
      else if (strnicmp(*argv, "NODE=", 5) == 0)
	{
	  bp = *argv + 5;
	  board = strtol (bp, &ep, 0);
	  if (ep == bp || *ep != '\0') 
	    {
	      fprintf (stderr, "%s: %s: expected integer argument\n", 
		       progname, bp);
	      exit(1);
	    }
	}
#endif
      else if (strnicmp(*argv, "PORT=", 5) == 0)
	{
	  bp = *argv + 5;
	  port = strtol (bp, &ep, 0);
	  if (ep == bp || *ep != '\0')
	    {
	      fprintf (stderr, "%s: %s: expected integer argument\n", 
		       progname, bp);
	      exit(1);
	    }
	}
      else
	{
	  break;
	}

      cmdindx++;
    }

  if (argc == 0)
    {
      fprintf (stderr,
	       "Usage: load %s [options] program [arguments]\n", progname);
      exit (1);
    }

  err = AIOAcquirePort (&hardware, &board, &port, &AIOhandle);
  if (err != AIO_SUCCESS)
    {
      switch (err)
	{
	case AIO_PORT_NOT_AVAILABLE:
	  fprintf (stderr, "Port not available\n");
	  break;

	case AIO_BOARD_NUMBER_INVALID:
	case AIO_PORT_NUMBER_INVALID:
	  fprintf (stderr, "No such port\n");
	  break;

	default:
	  fprintf (stderr, "Could not open port: %d\n", err);
	  break;
	}

      exit (1);
    }

  err = AIOConfigurePort (AIOhandle, bitRate, dataBits, stopBits, parityMode,
			  AIO_HARDWARE_FLOW_CONTROL_OFF);

  if (err == AIO_QUALIFIED_SUCCESS)
    {
      AIOPORTCONFIG portConfig;

      fprintf (stderr, "Port configuration changed!\n");

      portConfig.returnLength = sizeof(portConfig);
      AIOGetPortConfiguration (AIOhandle, &portConfig, NULL);

      fprintf (stderr,
	       "  Bit Rate: %s, Data Bits: %c, Stop Bits: %s, Parity: %c,\
 Flow:%s\n",
	       bitRateTable[portConfig.bitRate].bitRateString,
	       dataBitsTable[portConfig.dataBits],
	       stopBitsTable[portConfig.stopBits],
	       parity[portConfig.parityMode],
	       portConfig.flowCtrlMode ? "ON" : "OFF");
    }
  else if (err != AIO_SUCCESS)
    {
      fprintf (stderr, "Could not configure port: %d\n", err);
      AIOReleasePort (AIOhandle);
      exit (1);
    }

  if (AIOSetExternalControl(AIOhandle, AIO_EXTERNAL_CONTROL,
			    (AIO_EXTCTRL_DTR | AIO_EXTCTRL_RTS))
      != AIO_SUCCESS)
    {
      LONG extStatus, chgdExtStatus;

      fprintf (stderr, "Could not set desired port controls!\n");
      AIOGetExternalStatus (AIOhandle, &extStatus, &chgdExtStatus);
      fprintf (stderr, "Port controls now: %d, %d\n", extStatus, 
	       chgdExtStatus);
    }

  /* Register ourselves as an alternate debugger.  */
  memset (&s, 0, sizeof s);
  s.DDSResourceTag = ((struct ResourceTagStructure *)
		      AllocateResourceTag (GetNLMHandle (),
					   (BYTE *)"gdbserver",
					   DebuggerSignature));
  if (s.DDSResourceTag == 0)
    {
      fprintf (stderr, "AllocateResourceTag failed\n");
      AIOReleasePort (AIOhandle);
      exit (1);
    }
  s.DDSdebuggerEntry = handle_exception;
  s.DDSFlags = TSS_FRAME_BIT;

  err = RegisterDebuggerRTag (&s, AT_FIRST);
  if (err != 0)
    {
      fprintf (stderr, "RegisterDebuggerRTag failed\n");
      AIOReleasePort (AIOhandle);
      exit (1);
    }

  /* Get the command line we were invoked with, and advance it past
     our name and the board and port arguments.  */
  cmdlin = getcmd ((char *) NULL);
  for (i = 0; i < cmdindx; i++)
    {
      while (! isspace (*cmdlin))
	++cmdlin;
      while (isspace (*cmdlin))
	++cmdlin;
    }
  
  /* In case GDB is started before us, ack any packets (presumably
     "$?#xx") sitting there.  */
  if (! putDebugChar ('+'))
    {
      fprintf (stderr, "putDebugChar failed\n");
      UnRegisterDebugger (&s);
      AIOReleasePort (AIOhandle);
      exit (1);
    }

  mainthread = GetThreadID ();

  if (remote_debug > 0)
    ConsolePrintf ("About to call LoadModule with \"%s\" %08x\r\n",
		   cmdlin, __GetScreenID (GetCurrentScreen()));

  /* Start up the module to be debugged.  */
  err = LoadModule ((struct ScreenStruct *) __GetScreenID (GetCurrentScreen()),
		    (BYTE *)cmdlin, LO_DEBUG);
  if (err != 0)
    {
      fprintf (stderr, "LoadModule failed: %d\n", err);
      UnRegisterDebugger (&s);
      AIOReleasePort (AIOhandle);
      exit (1);
    }

  /* Wait for the debugger to wake us up.  */
  if (remote_debug > 0)
    ConsolePrintf ("Suspending main thread (%08x)\r\n", mainthread);
  SuspendThread (mainthread);
  if (remote_debug > 0)
    ConsolePrintf ("Resuming main thread (%08x)\r\n", mainthread);

  /* If we are woken up, print an optional error message, deregister
     ourselves and exit.  */
  if (error_message != NULL)
    fprintf (stderr, "%s\n", error_message);
  UnRegisterDebugger (&s);
  AIOReleasePort (AIOhandle);
  exit (0);
}