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/* Memory breakpoint operations for the remote server for GDB.

   Copyright (C) 2002, 2003, 2005, 2007, 2008 Free Software Foundation, Inc.

   Contributed by MontaVista Software.

   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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "server.h"

const unsigned char *breakpoint_data;

int breakpoint_len;

#define MAX_BREAKPOINT_LEN 8

struct breakpoint

{

  struct breakpoint *next;

  CORE_ADDR pc;

  unsigned char old_data[MAX_BREAKPOINT_LEN];

  /* Non-zero iff we are stepping over this breakpoint.  */

  int reinserting;

  /* Non-NULL iff this breakpoint was inserted to step over

     another one.  Points to the other breakpoint (which is also

     in the *next chain somewhere).  */

  struct breakpoint *breakpoint_to_reinsert;

  /* Function to call when we hit this breakpoint.  If it returns 1,

     the breakpoint will be deleted; 0, it will be reinserted for

     another round.  */

  int (*handler) (CORE_ADDR);

};

struct breakpoint *breakpoints;

void

set_breakpoint_at (CORE_ADDR where, int (*handler) (CORE_ADDR))

{

  struct breakpoint *bp;

  if (breakpoint_data == NULL)

    error ("Target does not support breakpoints.");

  bp = malloc (sizeof (struct breakpoint));

  memset (bp, 0, sizeof (struct breakpoint));

  (*the_target->read_memory) (where, bp->old_data,

                              breakpoint_len);

  (*the_target->write_memory) (where, breakpoint_data,

                               breakpoint_len);

  bp->pc = where;

  bp->handler = handler;

  bp->next = breakpoints;

  breakpoints = bp;

}

static void

delete_breakpoint (struct breakpoint *bp)

{

  struct breakpoint *cur;

  if (breakpoints == bp)

    {

      breakpoints = bp->next;

      (*the_target->write_memory) (bp->pc, bp->old_data,

                                   breakpoint_len);

      free (bp);

      return;

    }

  cur = breakpoints;

  while (cur->next)

    {

      if (cur->next == bp)

        {

          cur->next = bp->next;

          (*the_target->write_memory) (bp->pc, bp->old_data,

                                       breakpoint_len);

          free (bp);

          return;

        }

    }

  warning ("Could not find breakpoint in list.");

}

static struct breakpoint *

find_breakpoint_at (CORE_ADDR where)

{

  struct breakpoint *bp = breakpoints;

  while (bp != NULL)

    {

      if (bp->pc == where)

        return bp;

      bp = bp->next;

    }

  return NULL;

}

void

delete_breakpoint_at (CORE_ADDR addr)

{

  struct breakpoint *bp = find_breakpoint_at (addr);

  if (bp != NULL)

    delete_breakpoint (bp);

}

static int

reinsert_breakpoint_handler (CORE_ADDR stop_pc)

{

  struct breakpoint *stop_bp, *orig_bp;

  stop_bp = find_breakpoint_at (stop_pc);

  if (stop_bp == NULL)

    error ("lost the stopping breakpoint.");

  orig_bp = stop_bp->breakpoint_to_reinsert;

  if (orig_bp == NULL)

    error ("no breakpoint to reinsert");

  (*the_target->write_memory) (orig_bp->pc, breakpoint_data,

                               breakpoint_len);

  orig_bp->reinserting = 0;

  return 1;

}

void

reinsert_breakpoint_by_bp (CORE_ADDR stop_pc, CORE_ADDR stop_at)

{

  struct breakpoint *bp, *orig_bp;

  orig_bp = find_breakpoint_at (stop_pc);

  if (orig_bp == NULL)

    error ("Could not find original breakpoint in list.");

  set_breakpoint_at (stop_at, reinsert_breakpoint_handler);

  bp = find_breakpoint_at (stop_at);

  if (bp == NULL)

    error ("Could not find breakpoint in list (reinserting by breakpoint).");

  bp->breakpoint_to_reinsert = orig_bp;

  (*the_target->write_memory) (orig_bp->pc, orig_bp->old_data,

                               breakpoint_len);

  orig_bp->reinserting = 1;

}

void

uninsert_breakpoint (CORE_ADDR stopped_at)

{

  struct breakpoint *bp;

  bp = find_breakpoint_at (stopped_at);

  if (bp == NULL)

    error ("Could not find breakpoint in list (uninserting).");

  (*the_target->write_memory) (bp->pc, bp->old_data,

                               breakpoint_len);

  bp->reinserting = 1;

}

void

reinsert_breakpoint (CORE_ADDR stopped_at)

{

  struct breakpoint *bp;

  bp = find_breakpoint_at (stopped_at);

  if (bp == NULL)

    error ("Could not find breakpoint in list (uninserting).");

  if (! bp->reinserting)

    error ("Breakpoint already inserted at reinsert time.");

  (*the_target->write_memory) (bp->pc, breakpoint_data,

                               breakpoint_len);

  bp->reinserting = 0;

}

int

check_breakpoints (CORE_ADDR stop_pc)

{

  struct breakpoint *bp;

  bp = find_breakpoint_at (stop_pc);

  if (bp == NULL)

    return 0;

  if (bp->reinserting)

    {

      warning ("Hit a removed breakpoint?");

      return 0;

    }

  if ((*bp->handler) (bp->pc))

    {

      delete_breakpoint (bp);

      return 2;

    }

  else

    return 1;

}

void

set_breakpoint_data (const unsigned char *bp_data, int bp_len)

{

  breakpoint_data = bp_data;

  breakpoint_len = bp_len;

}

void

check_mem_read (CORE_ADDR mem_addr, unsigned char *buf, int mem_len)

{

  struct breakpoint *bp = breakpoints;

  CORE_ADDR mem_end = mem_addr + mem_len;

  for (; bp != NULL; bp = bp->next)

    {

      CORE_ADDR bp_end = bp->pc + breakpoint_len;

      CORE_ADDR start, end;

      int copy_offset, copy_len, buf_offset;

      if (mem_addr >= bp_end)

        continue;

      if (bp->pc >= mem_end)

        continue;

      start = bp->pc;

      if (mem_addr > start)

        start = mem_addr;

      end = bp_end;

      if (end > mem_end)

        end = mem_end;

      copy_len = end - start;

      copy_offset = start - bp->pc;

      buf_offset = start - mem_addr;

      memcpy (buf + buf_offset, bp->old_data + copy_offset, copy_len);

    }

}

void

check_mem_write (CORE_ADDR mem_addr, unsigned char *buf, int mem_len)

{

  struct breakpoint *bp = breakpoints;

  CORE_ADDR mem_end = mem_addr + mem_len;

  for (; bp != NULL; bp = bp->next)

    {

      CORE_ADDR bp_end = bp->pc + breakpoint_len;

      CORE_ADDR start, end;

      int copy_offset, copy_len, buf_offset;

      if (mem_addr >= bp_end)

        continue;

      if (bp->pc >= mem_end)

        continue;

      start = bp->pc;

      if (mem_addr > start)

        start = mem_addr;

      end = bp_end;

      if (end > mem_end)

        end = mem_end;

      copy_len = end - start;

      copy_offset = start - bp->pc;

      buf_offset = start - mem_addr;

      memcpy (bp->old_data + copy_offset, buf + buf_offset, copy_len);

      if (bp->reinserting == 0)

        memcpy (buf + buf_offset, breakpoint_data + copy_offset, copy_len);

    }

}

/* Delete all breakpoints.  */

void

delete_all_breakpoints (void)

{

  while (breakpoints)

    delete_breakpoint (breakpoints);

}