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
60 int
dwarf_siblingof(die,result)61 dwarf_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 }
161 INTDEF(dwarf_siblingof)
162