1/* Return reference offset represented by attribute.
2   Copyright (C) 2003-2010, 2014 Red Hat, Inc.
3   This file is part of elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 2003.
5
6   This file is free software; you can redistribute it and/or modify
7   it under the terms of either
8
9     * the GNU Lesser General Public License as published by the Free
10       Software Foundation; either version 3 of the License, or (at
11       your option) any later version
12
13   or
14
15     * the GNU General Public License as published by the Free
16       Software Foundation; either version 2 of the License, or (at
17       your option) any later version
18
19   or both in parallel, as here.
20
21   elfutils is distributed in the hope that it will be useful, but
22   WITHOUT ANY WARRANTY; without even the implied warranty of
23   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
24   General Public License for more details.
25
26   You should have received copies of the GNU General Public License and
27   the GNU Lesser General Public License along with this program.  If
28   not, see <http://www.gnu.org/licenses/>.  */
29
30#ifdef HAVE_CONFIG_H
31# include <config.h>
32#endif
33
34#include <dwarf.h>
35#include "libdwP.h"
36
37int
38internal_function
39__libdw_formref (Dwarf_Attribute *attr, Dwarf_Off *return_offset)
40{
41  const unsigned char *datap = attr->valp;
42  const unsigned char *endp = attr->cu->endp;
43
44  if (attr->valp == NULL)
45    {
46      __libdw_seterrno (DWARF_E_INVALID_REFERENCE);
47      return -1;
48    }
49
50  switch (attr->form)
51    {
52    case DW_FORM_ref1:
53      if (datap + 1 > endp)
54	{
55	invalid:
56	  __libdw_seterrno (DWARF_E_INVALID_DWARF);
57	  return -1;
58	}
59      *return_offset = *attr->valp;
60      break;
61
62    case DW_FORM_ref2:
63      if (datap + 2 > endp)
64	goto invalid;
65      *return_offset = read_2ubyte_unaligned (attr->cu->dbg, attr->valp);
66      break;
67
68    case DW_FORM_ref4:
69      if (datap + 4 > endp)
70	goto invalid;
71      *return_offset = read_4ubyte_unaligned (attr->cu->dbg, attr->valp);
72      break;
73
74    case DW_FORM_ref8:
75      if (datap + 8 > endp)
76	goto invalid;
77      *return_offset = read_8ubyte_unaligned (attr->cu->dbg, attr->valp);
78      break;
79
80    case DW_FORM_ref_udata:
81      if (datap + 1 > endp)
82	goto invalid;
83      get_uleb128 (*return_offset, datap, endp);
84      break;
85
86    case DW_FORM_ref_addr:
87    case DW_FORM_ref_sig8:
88    case DW_FORM_GNU_ref_alt:
89    case DW_FORM_ref_sup4:
90    case DW_FORM_ref_sup8:
91      /* These aren't handled by dwarf_formref, only by dwarf_formref_die.  */
92      __libdw_seterrno (DWARF_E_INVALID_REFERENCE);
93      return -1;
94
95    default:
96      __libdw_seterrno (DWARF_E_NO_REFERENCE);
97      return -1;
98    }
99
100  return 0;
101}
102
103/* This is the old public entry point.
104   It is now deprecated in favor of dwarf_formref_die.  */
105int
106dwarf_formref (Dwarf_Attribute *attr, Dwarf_Off *return_offset)
107{
108  if (attr == NULL)
109    return -1;
110
111  return __libdw_formref (attr, return_offset);
112}
113