1 /* simple.c -- BFD simple client routines
2 Copyright (C) 2002-2023 Free Software Foundation, Inc.
3 Contributed by MontaVista Software, Inc.
4
5 This file is part of BFD, the Binary File Descriptor library.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
20 MA 02110-1301, USA. */
21
22 #include "sysdep.h"
23 #include "bfd.h"
24 #include "libbfd.h"
25 #include "bfdlink.h"
26 #include "genlink.h"
27
28 static void
29 simple_dummy_add_to_set (struct bfd_link_info * info ATTRIBUTE_UNUSED,
30 struct bfd_link_hash_entry *entry ATTRIBUTE_UNUSED,
31 bfd_reloc_code_real_type reloc ATTRIBUTE_UNUSED,
32 bfd *abfd ATTRIBUTE_UNUSED,
33 asection *sec ATTRIBUTE_UNUSED,
34 bfd_vma value ATTRIBUTE_UNUSED)
35 {
36 }
37
38 static void
39 simple_dummy_constructor (struct bfd_link_info * info ATTRIBUTE_UNUSED,
40 bool constructor ATTRIBUTE_UNUSED,
41 const char *name ATTRIBUTE_UNUSED,
42 bfd *abfd ATTRIBUTE_UNUSED,
43 asection *sec ATTRIBUTE_UNUSED,
44 bfd_vma value ATTRIBUTE_UNUSED)
45 {
46 }
47
48 static void
49 simple_dummy_multiple_common (struct bfd_link_info * info ATTRIBUTE_UNUSED,
50 struct bfd_link_hash_entry * entry ATTRIBUTE_UNUSED,
51 bfd * abfd ATTRIBUTE_UNUSED,
52 enum bfd_link_hash_type type ATTRIBUTE_UNUSED,
53 bfd_vma size ATTRIBUTE_UNUSED)
54 {
55 }
56
57 static void
58 simple_dummy_warning (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
59 const char *warning ATTRIBUTE_UNUSED,
60 const char *symbol ATTRIBUTE_UNUSED,
61 bfd *abfd ATTRIBUTE_UNUSED,
62 asection *section ATTRIBUTE_UNUSED,
63 bfd_vma address ATTRIBUTE_UNUSED)
64 {
65 }
66
67 static void
68 simple_dummy_undefined_symbol (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
69 const char *name ATTRIBUTE_UNUSED,
70 bfd *abfd ATTRIBUTE_UNUSED,
71 asection *section ATTRIBUTE_UNUSED,
72 bfd_vma address ATTRIBUTE_UNUSED,
73 bool fatal ATTRIBUTE_UNUSED)
74 {
75 }
76
77 static void
78 simple_dummy_reloc_overflow (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
79 struct bfd_link_hash_entry *entry ATTRIBUTE_UNUSED,
80 const char *name ATTRIBUTE_UNUSED,
81 const char *reloc_name ATTRIBUTE_UNUSED,
82 bfd_vma addend ATTRIBUTE_UNUSED,
83 bfd *abfd ATTRIBUTE_UNUSED,
84 asection *section ATTRIBUTE_UNUSED,
85 bfd_vma address ATTRIBUTE_UNUSED)
86 {
87 }
88
89 static void
90 simple_dummy_reloc_dangerous (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
91 const char *message ATTRIBUTE_UNUSED,
92 bfd *abfd ATTRIBUTE_UNUSED,
93 asection *section ATTRIBUTE_UNUSED,
94 bfd_vma address ATTRIBUTE_UNUSED)
95 {
96 }
97
98 static void
99 simple_dummy_unattached_reloc (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
100 const char *name ATTRIBUTE_UNUSED,
101 bfd *abfd ATTRIBUTE_UNUSED,
102 asection *section ATTRIBUTE_UNUSED,
103 bfd_vma address ATTRIBUTE_UNUSED)
104 {
105 }
106
107 static void
108 simple_dummy_multiple_definition (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
109 struct bfd_link_hash_entry *h ATTRIBUTE_UNUSED,
110 bfd *nbfd ATTRIBUTE_UNUSED,
111 asection *nsec ATTRIBUTE_UNUSED,
112 bfd_vma nval ATTRIBUTE_UNUSED)
113 {
114 }
115
116 static void
117 simple_dummy_einfo (const char *fmt ATTRIBUTE_UNUSED, ...)
118 {
119 }
120
121 struct saved_output_info
122 {
123 bfd_vma offset;
124 asection *section;
125 };
126
127 struct saved_offsets
128 {
129 unsigned int section_count;
130 struct saved_output_info *sections;
131 };
132
133 /* The sections in ABFD may already have output sections and offsets
134 set if we are here during linking.
135
136 DWARF-2 specifies offsets into debug sections in many cases and
137 bfd_simple_get_relocated_section_contents is called to relocate
138 debug info for a single relocatable object file. So we want
139 offsets relative to that object file's sections, not offsets in the
140 output file. For that reason, reset a debug section->output_offset
141 to zero.
142
143 If not called during linking then set section->output_section to
144 point back to the input section, because output_section must not be
145 NULL when calling the relocation routines.
146
147 Save the original output offset and section to restore later. */
148
149 static void
150 simple_save_output_info (bfd *abfd ATTRIBUTE_UNUSED,
151 asection *section,
152 void *ptr)
153 {
154 struct saved_offsets *saved_offsets = (struct saved_offsets *) ptr;
155 struct saved_output_info *output_info;
156
157 output_info = &saved_offsets->sections[section->index];
158 output_info->offset = section->output_offset;
159 output_info->section = section->output_section;
160 if ((section->flags & SEC_DEBUGGING) != 0
161 || section->output_section == NULL)
162 {
163 section->output_offset = 0;
164 section->output_section = section;
165 }
166 }
167
168 static void
169 simple_restore_output_info (bfd *abfd ATTRIBUTE_UNUSED,
170 asection *section,
171 void *ptr)
172 {
173 struct saved_offsets *saved_offsets = (struct saved_offsets *) ptr;
174 struct saved_output_info *output_info;
175
176 if (section->index >= saved_offsets->section_count)
177 return;
178
179 output_info = &saved_offsets->sections[section->index];
180 section->output_offset = output_info->offset;
181 section->output_section = output_info->section;
182 }
183
184 /*
185 FUNCTION
186 bfd_simple_relocate_secton
187
188 SYNOPSIS
189 bfd_byte *bfd_simple_get_relocated_section_contents
190 (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
191
192 DESCRIPTION
193 Returns the relocated contents of section @var{sec}. The symbols in
194 @var{symbol_table} will be used, or the symbols from @var{abfd} if
195 @var{symbol_table} is NULL. The output offsets for debug sections will
196 be temporarily reset to 0. The result will be stored at @var{outbuf}
197 or allocated with @code{bfd_malloc} if @var{outbuf} is @code{NULL}.
198
199 Returns @code{NULL} on a fatal error; ignores errors applying
200 particular relocations.
201 */
202
203 bfd_byte *
204 bfd_simple_get_relocated_section_contents (bfd *abfd,
205 asection *sec,
206 bfd_byte *outbuf,
207 asymbol **symbol_table)
208 {
209 struct bfd_link_info link_info;
210 struct bfd_link_order link_order;
211 struct bfd_link_callbacks callbacks;
212 bfd_byte *contents;
213 struct saved_offsets saved_offsets;
214 bfd *link_next;
215
216 /* Don't apply relocation on executable and shared library. See
217 PR 4756. */
218 if ((abfd->flags & (HAS_RELOC | EXEC_P | DYNAMIC)) != HAS_RELOC
219 || ! (sec->flags & SEC_RELOC))
220 {
221 if (!bfd_get_full_section_contents (abfd, sec, &outbuf))
222 return NULL;
223 return outbuf;
224 }
225
226 /* In order to use bfd_get_relocated_section_contents, we need
227 to forge some data structures that it expects. */
228
229 /* Fill in the bare minimum number of fields for our purposes. */
230 memset (&link_info, 0, sizeof (link_info));
231 link_info.output_bfd = abfd;
232 link_info.input_bfds = abfd;
233 link_info.input_bfds_tail = &abfd->link.next;
234
235 link_next = abfd->link.next;
236 abfd->link.next = NULL;
237 link_info.hash = _bfd_generic_link_hash_table_create (abfd);
238 link_info.callbacks = &callbacks;
239 /* Make sure that any fields not initialised below do not
240 result in a potential indirection via a random address. */
241 memset (&callbacks, 0, sizeof callbacks);
242 callbacks.warning = simple_dummy_warning;
243 callbacks.undefined_symbol = simple_dummy_undefined_symbol;
244 callbacks.reloc_overflow = simple_dummy_reloc_overflow;
245 callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
246 callbacks.unattached_reloc = simple_dummy_unattached_reloc;
247 callbacks.multiple_definition = simple_dummy_multiple_definition;
248 callbacks.einfo = simple_dummy_einfo;
249 callbacks.multiple_common = simple_dummy_multiple_common;
250 callbacks.constructor = simple_dummy_constructor;
251 callbacks.add_to_set = simple_dummy_add_to_set;
252
253 memset (&link_order, 0, sizeof (link_order));
254 link_order.next = NULL;
255 link_order.type = bfd_indirect_link_order;
256 link_order.offset = 0;
257 link_order.size = sec->size;
258 link_order.u.indirect.section = sec;
259
260 contents = NULL;
261
262 saved_offsets.section_count = abfd->section_count;
263 saved_offsets.sections = malloc (sizeof (*saved_offsets.sections)
264 * saved_offsets.section_count);
265 if (saved_offsets.sections == NULL)
266 goto out1;
267 bfd_map_over_sections (abfd, simple_save_output_info, &saved_offsets);
268
269 if (symbol_table == NULL)
270 {
271 if (!bfd_generic_link_read_symbols (abfd))
272 goto out2;
273 symbol_table = _bfd_generic_link_get_symbols (abfd);
274 }
275
276 contents = bfd_get_relocated_section_contents (abfd,
277 &link_info,
278 &link_order,
279 outbuf,
280 false,
281 symbol_table);
282 out2:
283 bfd_map_over_sections (abfd, simple_restore_output_info, &saved_offsets);
284 free (saved_offsets.sections);
285 out1:
286 _bfd_generic_link_hash_table_free (abfd);
287 abfd->link.next = link_next;
288 return contents;
289 }