libdwfl/dwfl_getmodules.c

/* Iterate through modules.
   Copyright (C) 2005, 2008 Red Hat, Inc.
   This file is part of Red Hat elfutils.

   Red Hat elfutils 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; version 2 of the License.

   Red Hat elfutils 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 Red Hat elfutils; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.

   In addition, as a special exception, Red Hat, Inc. gives You the
   additional right to link the code of Red Hat elfutils with code licensed
   under any Open Source Initiative certified open source license
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   this file solely under the GPL without exception.

   Red Hat elfutils is an included package of the Open Invention Network.
   An included package of the Open Invention Network is a package for which
   Open Invention Network licensees cross-license their patents.  No patent
   license is granted, either expressly or impliedly, by designation as an
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#include "libdwflP.h"

ptrdiff_t
dwfl_getmodules (Dwfl *dwfl,
		 int (*callback) (Dwfl_Module *, void **,
				  const char *, Dwarf_Addr, void *),
		 void *arg,
		 ptrdiff_t offset)
{
  if (dwfl == NULL)
    return -1;

  /* We iterate through the linked list when it's all we have.
     But continuing from an offset is slow that way.  So when
     DWFL->lookup_module is populated, we can instead keep our
     place by jumping directly into the array.  Since the actions
     of a callback could cause it to get populated, we must
     choose the style of place-holder when we return an offset,
     and we encode the choice in the low bits of that value.  */

  Dwfl_Module *m = dwfl->modulelist;

  if ((offset & 3) == 1)
    {
      offset >>= 2;
      for (ptrdiff_t pos = 0; pos < offset; ++pos)
	if (m == NULL)
	  return -1;
	else
	  m = m->next;
    }
  else if (((offset & 3) == 2) && likely (dwfl->lookup_module != NULL))
    {
      offset >>= 2;

      if ((size_t) offset - 1 == dwfl->lookup_elts)
	return 0;

      if (unlikely ((size_t) offset - 1 > dwfl->lookup_elts))
	return -1;

      m = dwfl->lookup_module[offset - 1];
      if (unlikely (m == NULL))
	return -1;
    }
  else if (offset != 0)
    {
      __libdwfl_seterrno (DWFL_E_BADSTROFF);
      return -1;
    }

  while (m != NULL)
    {
      int ok = (*callback) (MODCB_ARGS (m), arg);
      ++offset;
      m = m->next;
      if (ok != DWARF_CB_OK)
	return ((dwfl->lookup_module == NULL) ? ((offset << 2) | 1)
		: (((m == NULL ? (ptrdiff_t) dwfl->lookup_elts + 1
		     : m->segment + 1) << 2) | 2));
    }
  return 0;
}
INTDEF (dwfl_getmodules)