binutils-gdb/gdb/bfd-target.c

/* Very simple "bfd" target, for GDB, the GNU debugger.

   Copyright (C) 2003, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.

   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 "defs.h"
#include "target.h"
#include "bfd-target.h"
#include "gdb_assert.h"
#include "gdb_string.h"

/* Locate all mappable sections of a BFD file, filling in a target
   section for each.  */

struct section_closure
{
  struct section_table *end;
};

static void
add_to_section_table (struct bfd *abfd, struct bfd_section *asect,
		      void *closure)
{
  struct section_closure *pp = closure;
  flagword aflag;

  /* NOTE: cagney/2003-10-22: Is this pruning useful?  */
  aflag = bfd_get_section_flags (abfd, asect);
  if (!(aflag & SEC_ALLOC))
    return;
  if (bfd_section_size (abfd, asect) == 0)
    return;
  pp->end->bfd = abfd;
  pp->end->the_bfd_section = asect;
  pp->end->addr = bfd_section_vma (abfd, asect);
  pp->end->endaddr = pp->end->addr + bfd_section_size (abfd, asect);
  pp->end++;
}

void
build_target_sections_from_bfd (struct target_ops *targ, struct bfd *abfd)
{
  unsigned count;
  struct section_table *start;
  struct section_closure cl;

  count = bfd_count_sections (abfd);
  target_resize_to_sections (targ, count);
  start = targ->to_sections;
  cl.end = targ->to_sections;
  bfd_map_over_sections (abfd, add_to_section_table, &cl);
  gdb_assert (cl.end - start <= count);
}

static LONGEST
target_bfd_xfer_partial (struct target_ops *ops,
			 enum target_object object,
			 const char *annex, gdb_byte *readbuf,
			 const gdb_byte *writebuf,
			 ULONGEST offset, LONGEST len)
{
  switch (object)
    {
    case TARGET_OBJECT_MEMORY:
      {
	struct section_table *s = target_section_by_addr (ops, offset);
	if (s == NULL)
	  return -1;
	/* If the length extends beyond the section, truncate it.  Be
           careful to not suffer from overflow (wish S contained a
           length).  */
	if ((offset - s->addr + len) > (s->endaddr - s->addr))
	  len = (s->endaddr - s->addr) - (offset - s->addr);
	if (readbuf != NULL
	    && !bfd_get_section_contents (s->bfd, s->the_bfd_section,
					  readbuf, offset - s->addr, len))
	  return -1;
#if 1
	if (writebuf != NULL)
	  return -1;
#else
	/* FIXME: cagney/2003-10-31: The BFD interface doesn't yet
           take a const buffer.  */
	if (writebuf != NULL
	    && !bfd_set_section_contents (s->bfd, s->the_bfd_section,
					  writebuf, offset - s->addr, len))
	  return -1;
#endif
	return len;
      }
    default:
      return -1;
    }
}

static void
target_bfd_xclose (struct target_ops *t, int quitting)
{
  bfd_close (t->to_data);
  xfree (t->to_sections);
  xfree (t);
}

struct target_ops *
target_bfd_reopen (struct bfd *bfd)
{
  struct target_ops *t = XZALLOC (struct target_ops);
  t->to_shortname = "bfd";
  t->to_longname = _("BFD backed target");
  t->to_doc = _("You should never see this");
  t->to_xfer_partial = target_bfd_xfer_partial;
  t->to_xclose = target_bfd_xclose;
  t->to_data = bfd;
  build_target_sections_from_bfd (t, bfd);
  return t;
}