1 /* Get information from dynamic table at the given index.
2 Copyright (C) 2000, 2001, 2002 Red Hat, Inc.
3 This file is part of Red Hat elfutils.
4 Written by Ulrich Drepper <drepper@redhat.com>, 2000.
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 <assert.h>
56 #include <gelf.h>
57 #include <string.h>
58
59 #include "libelfP.h"
60
61
62 GElf_Dyn *
gelf_getdyn(data,ndx,dst)63 gelf_getdyn (data, ndx, dst)
64 Elf_Data *data;
65 int ndx;
66 GElf_Dyn *dst;
67 {
68 Elf_Data_Scn *data_scn = (Elf_Data_Scn *) data;
69 GElf_Dyn *result = NULL;
70 Elf *elf;
71
72 if (data_scn == NULL)
73 return NULL;
74
75 if (unlikely (data_scn->d.d_type != ELF_T_DYN))
76 {
77 __libelf_seterrno (ELF_E_INVALID_HANDLE);
78 return NULL;
79 }
80
81 elf = data_scn->s->elf;
82
83 rwlock_rdlock (elf->lock);
84
85 /* This is the one place where we have to take advantage of the fact
86 that an `Elf_Data' pointer is also a pointer to `Elf_Data_Scn'.
87 The interface is broken so that it requires this hack. */
88 if (elf->class == ELFCLASS32)
89 {
90 Elf32_Dyn *src;
91
92 /* Here it gets a bit more complicated. The format of the symbol
93 table entries has to be adopted. The user better has provided
94 a buffer where we can store the information. While copying the
95 data we are converting the format. */
96 if (unlikely ((ndx + 1) * sizeof (Elf32_Dyn) > data_scn->d.d_size))
97 {
98 __libelf_seterrno (ELF_E_INVALID_INDEX);
99 goto out;
100 }
101
102 src = &((Elf32_Dyn *) data_scn->d.d_buf)[ndx];
103
104 /* This might look like a simple copy operation but it's
105 not. There are zero- and sign-extensions going on. */
106 dst->d_tag = src->d_tag;
107 /* It OK to copy `d_val' since `d_ptr' has the same size. */
108 dst->d_un.d_val = src->d_un.d_val;
109 }
110 else
111 {
112 /* If this is a 64 bit object it's easy. */
113 assert (sizeof (GElf_Dyn) == sizeof (Elf64_Dyn));
114
115 /* The data is already in the correct form. Just make sure the
116 index is OK. */
117 if (unlikely ((ndx + 1) * sizeof (GElf_Dyn) > data_scn->d.d_size))
118 {
119 __libelf_seterrno (ELF_E_INVALID_INDEX);
120 goto out;
121 }
122
123 *dst = ((GElf_Dyn *) data_scn->d.d_buf)[ndx];
124 }
125
126 result = dst;
127
128 out:
129 rwlock_unlock (elf->lock);
130
131 return result;
132 }
133