remote-st2000.c

早期freebsd实现

/* Remote debugging interface for Tandem ST2000 phone switch, for GDB.
   Copyright 1990, 1991, 1992 Free Software Foundation, Inc.
   Contributed by Cygnus Support.  Written by Jim Kingdon for Cygnus.

This file is part of GDB.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* This file was derived from remote-eb.c, which did a similar job, but for
   an AMD-29K running EBMON.  That file was in turn derived from remote.c
   as mentioned in the following comment (left in for comic relief):

  "This is like remote.c but is for an esoteric situation--
   having a 29k board in a PC hooked up to a unix machine with
   a serial line, and running ctty com1 on the PC, through which
   the unix machine can run ebmon.  Not to mention that the PC
   has PC/NFS, so it can access the same executables that gdb can,
   over the net in real time."

   In reality, this module talks to a debug monitor called 'STDEBUG', which
   runs in a phone switch.  We communicate with STDEBUG via either a direct
   serial line, or a TCP (or possibly TELNET) stream to a terminal multiplexor,
   which in turn talks to the phone switch. */

#include "defs.h"
#include "gdbcore.h"
#include "target.h"
#include "wait.h"
#include <varargs.h>
#include <signal.h>
#include <string.h>
#include <sys/types.h>
#include "serial.h"

extern struct target_ops st2000_ops;		/* Forward declaration */

static void st2000_close();
static void st2000_fetch_register();
static void st2000_store_register();

#define LOG_FILE "st2000.log"
#if defined (LOG_FILE)
FILE *log_file;
#endif

static int timeout = 24;

/* Descriptor for I/O to remote machine.  Initialize it to -1 so that
   st2000_open knows that we don't have a file open when the program
   starts.  */
int st2000_desc = -1;

/* Send data to stdebug.  Works just like printf. */

static void
printf_stdebug(va_alist)
     va_dcl
{
  va_list args;
  char *pattern;
  char buf[200];

  va_start(args);

  pattern = va_arg(args, char *);

  vsprintf(buf, pattern, args);
  if (!serial_write(buf, strlen(buf)))
    fprintf(stderr, "serial_write failed: %s\n", safe_strerror(errno));
}

/* Read a character from the remote system, doing all the fancy
   timeout stuff.  */
static int
readchar(timeout)
     int timeout;
{
  int c;

  c = serial_readchar(timeout);

#ifdef LOG_FILE
  putc(c & 0x7f, log_file);
#endif

  if (c >= 0)
    return c & 0x7f;

  if (c == -2)
    {
      if (timeout == 0)
	return c;		/* Polls shouldn't generate timeout errors */

      error("Timeout reading from remote system.");
    }

  perror_with_name("remote-st2000");
}

/* Scan input from the remote system, until STRING is found.  If DISCARD is
   non-zero, then discard non-matching input, else print it out.
   Let the user break out immediately.  */
static void
expect(string, discard)
     char *string;
     int discard;
{
  char *p = string;
  int c;

  immediate_quit = 1;
  while (1)
    {
      c = readchar(timeout);
      if (c == *p++)
	{
	  if (*p == '\0')
	    {
	      immediate_quit = 0;
	      return;
	    }
	}
      else
	{
	  if (!discard)
	    {
	      fwrite(string, 1, (p - 1) - string, stdout);
	      putchar((char)c);
	      fflush(stdout);
	    }
	  p = string;
	}
    }
}

/* Keep discarding input until we see the STDEBUG prompt.

   The convention for dealing with the prompt is that you
   o give your command
   o *then* wait for the prompt.

   Thus the last thing that a procedure does with the serial line
   will be an expect_prompt().  Exception:  st2000_resume does not
   wait for the prompt, because the terminal is being handed over
   to the inferior.  However, the next thing which happens after that
   is a st2000_wait which does wait for the prompt.
   Note that this includes abnormal exit, e.g. error().  This is
   necessary to prevent getting into states from which we can't
   recover.  */
static void
expect_prompt(discard)
     int discard;
{
#if defined (LOG_FILE)
  /* This is a convenient place to do this.  The idea is to do it often
     enough that we never lose much data if we terminate abnormally.  */
  fflush(log_file);
#endif
  expect ("dbug> ", discard);
}

/* Get a hex digit from the remote system & return its value.
   If ignore_space is nonzero, ignore spaces (not newline, tab, etc).  */
static int
get_hex_digit(ignore_space)
     int ignore_space;
{
  int ch;
  while (1)
    {
      ch = readchar(timeout);
      if (ch >= '0' && ch <= '9')
	return ch - '0';
      else if (ch >= 'A' && ch <= 'F')
	return ch - 'A' + 10;
      else if (ch >= 'a' && ch <= 'f')
	return ch - 'a' + 10;
      else if (ch == ' ' && ignore_space)
	;
      else
	{
	  expect_prompt(1);
	  error("Invalid hex digit from remote system.");
	}
    }
}

/* Get a byte from stdebug and put it in *BYT.  Accept any number
   leading spaces.  */
static void
get_hex_byte (byt)
     char *byt;
{
  int val;

  val = get_hex_digit (1) << 4;
  val |= get_hex_digit (0);
  *byt = val;
}

/* Get N 32-bit words from remote, each preceded by a space,
   and put them in registers starting at REGNO.  */
static void
get_hex_regs (n, regno)
     int n;
     int regno;
{
  long val;
  int i;

  for (i = 0; i < n; i++)
    {
      int j;
      
      val = 0;
      for (j = 0; j < 8; j++)
	val = (val << 4) + get_hex_digit (j == 0);
      supply_register (regno++, (char *) &val);
    }
}

/* This is called not only when we first attach, but also when the
   user types "run" after having attached.  */
static void
st2000_create_inferior (execfile, args, env)
     char *execfile;
     char *args;
     char **env;
{
  int entry_pt;

  if (args && *args)
    error("Can't pass arguments to remote STDEBUG process");

  if (execfile == 0 || exec_bfd == 0)
    error("No exec file specified");

  entry_pt = (int) bfd_get_start_address (exec_bfd);

#ifdef CREATE_INFERIOR_HOOK
  CREATE_INFERIOR_HOOK (0);		/* No process-ID */
#endif  

/* The "process" (board) is already stopped awaiting our commands, and
   the program is already downloaded.  We just set its PC and go.  */

  clear_proceed_status ();

  /* Tell wait_for_inferior that we've started a new process.  */
  init_wait_for_inferior ();

  /* Set up the "saved terminal modes" of the inferior
     based on what modes we are starting it with.  */
  target_terminal_init ();

  /* Install inferior's terminal modes.  */
  target_terminal_inferior ();

  /* insert_step_breakpoint ();  FIXME, do we need this?  */
  proceed ((CORE_ADDR)entry_pt, -1, 0);		/* Let 'er rip... */
}

/* Open a connection to a remote debugger.
   NAME is the filename used for communication.  */

static int baudrate = 9600;
static char dev_name[100];

static void
st2000_open(args, from_tty)
     char *args;
     int from_tty;
{
  int n;
  char junk[100];

  target_preopen(from_tty);
  
  n = sscanf(args, " %s %d %s", dev_name, &baudrate, junk);

  if (n != 2)
    error("Bad arguments.  Usage: target st2000 <device> <speed>\n\
or target st2000 <host> <port>\n");

  st2000_close(0);

  st2000_desc = serial_open(dev_name);

  serial_setbaudrate(baudrate);

  push_target(&st2000_ops);

#if defined (LOG_FILE)
  log_file = fopen (LOG_FILE, "w");
  if (log_file == NULL)
    perror_with_name (LOG_FILE);
#endif

  /* Hello?  Are you there?  */
  printf_stdebug("\003");	/* ^C wakes up dbug */
  
  expect_prompt(1);

  if (from_tty)
    printf("Remote %s connected to %s\n", target_shortname,
	   dev_name);
}

/* Close out all files and local state before this target loses control. */

static void
st2000_close (quitting)
     int quitting;
{
  serial_close();

#if defined (LOG_FILE)
  if (log_file) {
    if (ferror(log_file))
      fprintf(stderr, "Error writing log file.\n");
    if (fclose(log_file) != 0)
      fprintf(stderr, "Error closing log file.\n");
  }
#endif
}

/* Terminate the open connection to the remote debugger.
   Use this when you want to detach and do something else
   with your gdb.  */
static void
st2000_detach (from_tty)
     int from_tty;
{
  pop_target();		/* calls st2000_close to do the real work */
  if (from_tty)
    printf ("Ending remote %s debugging\n", target_shortname);
}
 
/* Tell the remote machine to resume.  */

static void
st2000_resume (step, sig)
     int step, sig;
{
  if (step)
    {
      printf_stdebug ("ST\r");
      /* Wait for the echo.  */
      expect ("ST\r", 1);
    }
  else
    {
      printf_stdebug ("GO\r");
      /* Swallow the echo.  */
      expect ("GO\r", 1);
    }
}

/* Wait until the remote machine stops, then return,
   storing status in STATUS just as `wait' would.  */

static int
st2000_wait (status)
     WAITTYPE *status;
{
  int old_timeout = timeout;

  WSETEXIT ((*status), 0);

  timeout = 0;		/* Don't time out -- user program is running. */

  expect_prompt(0);    /* Wait for prompt, outputting extraneous text */

  WSETSTOP ((*status), SIGTRAP);

  timeout = old_timeout;

  return 0;
}

/* Return the name of register number REGNO in the form input and output by
   STDEBUG.  Currently, REGISTER_NAMES just happens to contain exactly what
   STDEBUG wants.  Lets take advantage of that just as long as possible! */

static char *
get_reg_name (regno)
     int regno;
{
  static char buf[50];
  const char *p;
  char *b;

  b = buf;

  for (p = reg_names[regno]; *p; p++)
    *b++ = toupper(*p);
  *b = '\000';

  return buf;