1 /* Return string pointer from string section.
2 Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2008 Red Hat, Inc.
3 This file is part of Red Hat elfutils.
4 Contributed by Ulrich Drepper <drepper@redhat.com>, 1998.
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 <libelf.h>
56 #include <stddef.h>
57
58 #include "libelfP.h"
59
60
61 char *
elf_strptr(elf,idx,offset)62 elf_strptr (elf, idx, offset)
63 Elf *elf;
64 size_t idx;
65 size_t offset;
66 {
67 if (elf == NULL)
68 return NULL;
69
70 if (elf->kind != ELF_K_ELF)
71 {
72 __libelf_seterrno (ELF_E_INVALID_HANDLE);
73 return NULL;
74 }
75
76 rwlock_rdlock (elf->lock);
77
78 char *result = NULL;
79 Elf_Scn *strscn;
80
81 /* Find the section in the list. */
82 Elf_ScnList *runp = (elf->class == ELFCLASS32
83 || (offsetof (struct Elf, state.elf32.scns)
84 == offsetof (struct Elf, state.elf64.scns))
85 ? &elf->state.elf32.scns : &elf->state.elf64.scns);
86 while (1)
87 {
88 if (idx < runp->max)
89 {
90 if (idx < runp->cnt)
91 strscn = &runp->data[idx];
92 else
93 {
94 __libelf_seterrno (ELF_E_INVALID_INDEX);
95 goto out;
96 }
97 break;
98 }
99
100 idx -= runp->max;
101
102 runp = runp->next;
103 if (runp == NULL)
104 {
105 __libelf_seterrno (ELF_E_INVALID_INDEX);
106 goto out;
107 }
108 }
109
110 if (elf->class == ELFCLASS32)
111 {
112 if (unlikely (strscn->shdr.e32->sh_type != SHT_STRTAB))
113 {
114 /* This is no string section. */
115 __libelf_seterrno (ELF_E_INVALID_SECTION);
116 goto out;
117 }
118
119 if (unlikely (offset >= strscn->shdr.e32->sh_size))
120 {
121 /* The given offset is too big, it is beyond this section. */
122 __libelf_seterrno (ELF_E_OFFSET_RANGE);
123 goto out;
124 }
125 }
126 else
127 {
128 if (unlikely (strscn->shdr.e64->sh_type != SHT_STRTAB))
129 {
130 /* This is no string section. */
131 __libelf_seterrno (ELF_E_INVALID_SECTION);
132 goto out;
133 }
134
135 if (unlikely (offset >= strscn->shdr.e64->sh_size))
136 {
137 /* The given offset is too big, it is beyond this section. */
138 __libelf_seterrno (ELF_E_OFFSET_RANGE);
139 goto out;
140 }
141 }
142
143 if (strscn->rawdata_base == NULL && ! strscn->data_read)
144 {
145 rwlock_unlock (elf->lock);
146 rwlock_wrlock (elf->lock);
147 if (strscn->rawdata_base == NULL && ! strscn->data_read
148 /* Read the section data. */
149 && __libelf_set_rawdata_wrlock (strscn) != 0)
150 goto out;
151 }
152
153 if (likely (strscn->rawdata_base != NULL))
154 result = &strscn->rawdata_base[offset];
155 else
156 {
157 /* This is a file which is currently created. Use the list of
158 data blocks. */
159 struct Elf_Data_List *dl = &strscn->data_list;
160 while (dl != NULL)
161 {
162 if (offset >= (size_t) dl->data.d.d_off
163 && offset < dl->data.d.d_off + dl->data.d.d_size)
164 {
165 result = (char *) dl->data.d.d_buf + (offset - dl->data.d.d_off);
166 break;
167 }
168
169 dl = dl->next;
170 }
171 }
172
173 out:
174 rwlock_unlock (elf->lock);
175
176 return result;
177 }
178 INTDEF(elf_strptr)
179