1/* Get attributes of the DIE.
2   Copyright (C) 2004, 2005, 2008, 2009, 2014 Red Hat, Inc.
3   This file is part of elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 2004.
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 "libdwP.h"
35
36
37ptrdiff_t
38dwarf_getattrs (Dwarf_Die *die, int (*callback) (Dwarf_Attribute *, void *),
39		void *arg, ptrdiff_t offset)
40{
41  if (die == NULL)
42    return -1l;
43
44  if (unlikely (offset == 1))
45    return 1;
46
47  const unsigned char *die_addr;
48
49  /* Find the abbreviation entry.  */
50  Dwarf_Abbrev *abbrevp = __libdw_dieabbrev (die, &die_addr);
51
52  if (unlikely (abbrevp == DWARF_END_ABBREV))
53    {
54    invalid_dwarf:
55      __libdw_seterrno (DWARF_E_INVALID_DWARF);
56      return -1l;
57    }
58
59  /* This is where the attributes start.  */
60  const unsigned char *attrp = abbrevp->attrp;
61  const unsigned char *const offset_attrp = abbrevp->attrp + offset;
62
63  /* Go over the list of attributes.  */
64  Dwarf *dbg = die->cu->dbg;
65  const unsigned char *endp;
66  endp = ((const unsigned char *) dbg->sectiondata[IDX_debug_abbrev]->d_buf
67	  + dbg->sectiondata[IDX_debug_abbrev]->d_size);
68  while (1)
69    {
70      /* Are we still in bounds?  */
71      if (unlikely (attrp >= endp))
72	goto invalid_dwarf;
73
74      /* Get attribute name and form.  */
75      Dwarf_Attribute attr;
76      const unsigned char *remembered_attrp = attrp;
77
78      get_uleb128 (attr.code, attrp, endp);
79      if (unlikely (attrp >= endp))
80	goto invalid_dwarf;
81      get_uleb128 (attr.form, attrp, endp);
82
83      /* We can stop if we found the attribute with value zero.  */
84      if (attr.code == 0 && attr.form == 0)
85	/* Do not return 0 here - there would be no way to
86	   distinguish this value from the attribute at offset 0.
87	   Instead we return +1 which would never be a valid
88	   offset of an attribute.  */
89        return 1l;
90
91      /* If we are not to OFFSET_ATTRP yet, we just have to skip
92	 the values of the intervening attributes.  */
93      if (remembered_attrp >= offset_attrp)
94	{
95	  /* Fill in the rest.  */
96	  attr.valp = (unsigned char *) die_addr;
97	  attr.cu = die->cu;
98
99	  /* Now call the callback function.  */
100	  if (callback (&attr, arg) != DWARF_CB_OK)
101	    /* Return the offset of the start of the attribute, so that
102	       dwarf_getattrs() can be restarted from this point if the
103	       caller so desires.  */
104	    return remembered_attrp - abbrevp->attrp;
105	}
106
107      /* Skip over the rest of this attribute (if there is any).  */
108      if (attr.form != 0)
109	{
110	  size_t len = __libdw_form_val_len (die->cu, attr.form, die_addr);
111	  if (unlikely (len == (size_t) -1l))
112	    /* Something wrong with the file.  */
113	    return -1l;
114
115	  // __libdw_form_val_len will have done a bounds check.
116	  die_addr += len;
117	}
118    }
119  /* NOTREACHED */
120}
121