1/* Return sibling of given DIE.
2   Copyright (C) 2003, 2004, 2005, 2007, 2008 Red Hat, Inc.
3   This file is part of Red Hat elfutils.
4   Written by Ulrich Drepper <drepper@redhat.com>, 2003.
5
6   Red Hat elfutils is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by the
8   Free Software Foundation; version 2 of the License.
9
10   Red Hat elfutils is distributed in the hope that it will be useful, but
11   WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   General Public License for more details.
14
15   You should have received a copy of the GNU General Public License along
16   with Red Hat elfutils; if not, write to the Free Software Foundation,
17   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
18
19   In addition, as a special exception, Red Hat, Inc. gives You the
20   additional right to link the code of Red Hat elfutils with code licensed
21   under any Open Source Initiative certified open source license
22   (http://www.opensource.org/licenses/index.php) which requires the
23   distribution of source code with any binary distribution and to
24   distribute linked combinations of the two.  Non-GPL Code permitted under
25   this exception must only link to the code of Red Hat elfutils through
26   those well defined interfaces identified in the file named EXCEPTION
27   found in the source code files (the "Approved Interfaces").  The files
28   of Non-GPL Code may instantiate templates or use macros or inline
29   functions from the Approved Interfaces without causing the resulting
30   work to be covered by the GNU General Public License.  Only Red Hat,
31   Inc. may make changes or additions to the list of Approved Interfaces.
32   Red Hat's grant of this exception is conditioned upon your not adding
33   any new exceptions.  If you wish to add a new Approved Interface or
34   exception, please contact Red Hat.  You must obey the GNU General Public
35   License in all respects for all of the Red Hat elfutils code and other
36   code used in conjunction with Red Hat elfutils except the Non-GPL Code
37   covered by this exception.  If you modify this file, you may extend this
38   exception to your version of the file, but you are not obligated to do
39   so.  If you do not wish to provide this exception without modification,
40   you must delete this exception statement from your version and license
41   this file solely under the GPL without exception.
42
43   Red Hat elfutils is an included package of the Open Invention Network.
44   An included package of the Open Invention Network is a package for which
45   Open Invention Network licensees cross-license their patents.  No patent
46   license is granted, either expressly or impliedly, by designation as an
47   included package.  Should you wish to participate in the Open Invention
48   Network licensing program, please visit www.openinventionnetwork.com
49   <http://www.openinventionnetwork.com>.  */
50
51#ifdef HAVE_CONFIG_H
52# include <config.h>
53#endif
54
55#include "libdwP.h"
56#include <dwarf.h>
57#include <string.h>
58
59
60int
61dwarf_siblingof (die, result)
62     Dwarf_Die *die;
63     Dwarf_Die *result;
64{
65  /* Ignore previous errors.  */
66  if (die == NULL)
67    return -1;
68
69  if (result == NULL)
70    return -1;
71
72  if (result != die)
73    result->addr = NULL;
74
75  unsigned int level = 0;
76
77  /* Copy of the current DIE.  */
78  Dwarf_Die this_die = *die;
79  /* Temporary attributes we create.  */
80  Dwarf_Attribute sibattr;
81  /* Copy of the CU in the request.  */
82  sibattr.cu = this_die.cu;
83  /* That's the address we start looking.  */
84  unsigned char *addr = this_die.addr;
85  /* End of the buffer.  */
86  unsigned char *endp
87    = ((unsigned char *) sibattr.cu->dbg->sectiondata[IDX_debug_info]->d_buf
88       + sibattr.cu->end);
89
90  /* Search for the beginning of the next die on this level.  We
91     must not return the dies for children of the given die.  */
92  do
93    {
94      /* Find the end of the DIE or the sibling attribute.  */
95      addr = __libdw_find_attr (&this_die, DW_AT_sibling, &sibattr.code,
96				&sibattr.form);
97      if (sibattr.code == DW_AT_sibling)
98	{
99	  Dwarf_Off offset;
100	  sibattr.valp = addr;
101	  if (unlikely (__libdw_formref (&sibattr, &offset) != 0))
102	    /* Something went wrong.  */
103	    return -1;
104
105	  /* Compute the next address.  */
106	  addr = ((unsigned char *)
107		  sibattr.cu->dbg->sectiondata[IDX_debug_info]->d_buf
108		  + sibattr.cu->start + offset);
109	}
110      else if (unlikely (addr == NULL)
111	       || unlikely (this_die.abbrev == DWARF_END_ABBREV))
112	return -1;
113      else if (this_die.abbrev->has_children)
114	/* This abbreviation has children.  */
115	++level;
116
117
118      while (1)
119	{
120	  /* Make sure we are still in range.  Some producers might skip
121	     the trailing NUL bytes.  */
122	  if (addr >= endp)
123	    return 1;
124
125	  if (*addr != '\0')
126	    break;
127
128	  if (level-- == 0)
129	    {
130	      if (result != die)
131		result->addr = addr;
132	      /* No more sibling at all.  */
133	      return 1;
134	    }
135
136	  ++addr;
137	}
138
139      /* Initialize the 'current DIE'.  */
140      this_die.addr = addr;
141      this_die.abbrev = NULL;
142    }
143  while (level > 0);
144
145  /* Maybe we reached the end of the CU.  */
146  if (addr >= endp)
147    return 1;
148
149  /* Clear the entire DIE structure.  This signals we have not yet
150     determined any of the information.  */
151  memset (result, '\0', sizeof (Dwarf_Die));
152
153  /* We have the address.  */
154  result->addr = addr;
155
156  /* Same CU as the parent.  */
157  result->cu = sibattr.cu;
158
159  return 0;
160}
161INTDEF(dwarf_siblingof)
162