1/* simple.c -- BFD simple client routines
2   Copyright 2002, 2003, 2004
3   Free Software Foundation, Inc.
4   Contributed by MontaVista Software, Inc.
5
6   This file is part of BFD, the Binary File Descriptor library.
7
8   This program is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 2 of the License, or
11   (at your option) any later version.
12
13   This program is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with this program; if not, write to the Free Software
20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
21
22#include "bfd.h"
23#include "sysdep.h"
24#include "libbfd.h"
25#include "bfdlink.h"
26
27static bfd_boolean
28simple_dummy_warning (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
29		      const char *warning ATTRIBUTE_UNUSED,
30		      const char *symbol ATTRIBUTE_UNUSED,
31		      bfd *abfd ATTRIBUTE_UNUSED,
32		      asection *section ATTRIBUTE_UNUSED,
33		      bfd_vma address ATTRIBUTE_UNUSED)
34{
35  return TRUE;
36}
37
38static bfd_boolean
39simple_dummy_undefined_symbol (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
40			       const char *name ATTRIBUTE_UNUSED,
41			       bfd *abfd ATTRIBUTE_UNUSED,
42			       asection *section ATTRIBUTE_UNUSED,
43			       bfd_vma address ATTRIBUTE_UNUSED,
44			       bfd_boolean fatal ATTRIBUTE_UNUSED)
45{
46  return TRUE;
47}
48
49static bfd_boolean
50simple_dummy_reloc_overflow (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
51			     const char *name ATTRIBUTE_UNUSED,
52			     const char *reloc_name ATTRIBUTE_UNUSED,
53			     bfd_vma addend ATTRIBUTE_UNUSED,
54			     bfd *abfd ATTRIBUTE_UNUSED,
55			     asection *section ATTRIBUTE_UNUSED,
56			     bfd_vma address ATTRIBUTE_UNUSED)
57{
58  return TRUE;
59}
60
61static bfd_boolean
62simple_dummy_reloc_dangerous (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
63			      const char *message ATTRIBUTE_UNUSED,
64			      bfd *abfd ATTRIBUTE_UNUSED,
65			      asection *section ATTRIBUTE_UNUSED,
66			      bfd_vma address ATTRIBUTE_UNUSED)
67{
68  return TRUE;
69}
70
71static bfd_boolean
72simple_dummy_unattached_reloc (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
73			       const char *name ATTRIBUTE_UNUSED,
74			       bfd *abfd ATTRIBUTE_UNUSED,
75			       asection *section ATTRIBUTE_UNUSED,
76			       bfd_vma address ATTRIBUTE_UNUSED)
77{
78  return TRUE;
79}
80
81struct saved_output_info
82{
83  bfd_vma offset;
84  asection *section;
85};
86
87static void
88simple_save_output_info (bfd *abfd ATTRIBUTE_UNUSED,
89			 asection *section,
90			 void *ptr)
91{
92  struct saved_output_info *output_info = ptr;
93  output_info[section->index].offset = section->output_offset;
94  output_info[section->index].section = section->output_section;
95  section->output_offset = 0;
96  section->output_section = section;
97}
98
99static void
100simple_restore_output_info (bfd *abfd ATTRIBUTE_UNUSED,
101			    asection *section,
102			    void *ptr)
103{
104  struct saved_output_info *output_info = ptr;
105  section->output_offset = output_info[section->index].offset;
106  section->output_section = output_info[section->index].section;
107}
108
109/*
110FUNCTION
111	bfd_simple_relocate_secton
112
113SYNOPSIS
114	bfd_byte *bfd_simple_get_relocated_section_contents
115	  (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
116
117DESCRIPTION
118	Returns the relocated contents of section @var{sec}.  The symbols in
119	@var{symbol_table} will be used, or the symbols from @var{abfd} if
120	@var{symbol_table} is NULL.  The output offsets for all sections will
121	be temporarily reset to 0.  The result will be stored at @var{outbuf}
122	or allocated with @code{bfd_malloc} if @var{outbuf} is @code{NULL}.
123
124	Generally all sections in @var{abfd} should have their
125	@code{output_section} pointing back to the original section.
126
127	Returns @code{NULL} on a fatal error; ignores errors applying
128	particular relocations.
129*/
130
131bfd_byte *
132bfd_simple_get_relocated_section_contents (bfd *abfd,
133					   asection *sec,
134					   bfd_byte *outbuf,
135					   asymbol **symbol_table)
136{
137  struct bfd_link_info link_info;
138  struct bfd_link_order link_order;
139  struct bfd_link_callbacks callbacks;
140  bfd_byte *contents, *data;
141  int storage_needed;
142  void *saved_offsets;
143  bfd_size_type old_cooked_size;
144
145  if (! (sec->flags & SEC_RELOC))
146    {
147      bfd_size_type size = bfd_section_size (abfd, sec);
148
149      if (outbuf == NULL)
150	contents = bfd_malloc (size);
151      else
152	contents = outbuf;
153
154      if (contents)
155	bfd_get_section_contents (abfd, sec, contents, 0, size);
156
157      return contents;
158    }
159
160  /* In order to use bfd_get_relocated_section_contents, we need
161     to forge some data structures that it expects.  */
162
163  /* Fill in the bare minimum number of fields for our purposes.  */
164  memset (&link_info, 0, sizeof (link_info));
165  link_info.input_bfds = abfd;
166
167  link_info.hash = _bfd_generic_link_hash_table_create (abfd);
168  link_info.callbacks = &callbacks;
169  callbacks.warning = simple_dummy_warning;
170  callbacks.undefined_symbol = simple_dummy_undefined_symbol;
171  callbacks.reloc_overflow = simple_dummy_reloc_overflow;
172  callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
173  callbacks.unattached_reloc = simple_dummy_unattached_reloc;
174
175  memset (&link_order, 0, sizeof (link_order));
176  link_order.next = NULL;
177  link_order.type = bfd_indirect_link_order;
178  link_order.offset = 0;
179  link_order.size = bfd_section_size (abfd, sec);
180  link_order.u.indirect.section = sec;
181
182  data = NULL;
183  if (outbuf == NULL)
184    {
185      data = bfd_malloc (bfd_section_size (abfd, sec));
186      if (data == NULL)
187	return NULL;
188      outbuf = data;
189    }
190
191  /* The sections in ABFD may already have output sections and offsets set.
192     Because this function is primarily for debug sections, and GCC uses the
193     knowledge that debug sections will generally have VMA 0 when emitting
194     relocations between DWARF-2 sections (which are supposed to be
195     section-relative offsets anyway), we need to reset the output offsets
196     to zero.  We also need to arrange for section->output_section->vma plus
197     section->output_offset to equal section->vma, which we do by setting
198     section->output_section to point back to section.  Save the original
199     output offset and output section to restore later.  */
200  saved_offsets = malloc (sizeof (struct saved_output_info)
201			  * abfd->section_count);
202  if (saved_offsets == NULL)
203    {
204      if (data)
205	free (data);
206      return NULL;
207    }
208  bfd_map_over_sections (abfd, simple_save_output_info, saved_offsets);
209
210  if (symbol_table == NULL)
211    {
212      _bfd_generic_link_add_symbols (abfd, &link_info);
213
214      storage_needed = bfd_get_symtab_upper_bound (abfd);
215      symbol_table = bfd_malloc (storage_needed);
216      bfd_canonicalize_symtab (abfd, symbol_table);
217    }
218  else
219    storage_needed = 0;
220
221  /* This function might be called before _cooked_size has been set, and
222     bfd_perform_relocation needs _cooked_size to be valid.  */
223  old_cooked_size = sec->_cooked_size;
224  if (old_cooked_size == 0)
225    sec->_cooked_size = sec->_raw_size;
226
227  contents = bfd_get_relocated_section_contents (abfd,
228						 &link_info,
229						 &link_order,
230						 outbuf,
231						 0,
232						 symbol_table);
233  if (contents == NULL && data != NULL)
234    free (data);
235
236#if 0
237  /* NOTE: cagney/2003-04-05: This free, which was introduced on
238     2003-03-31 to stop a memory leak, caused a memory corruption
239     between GDB and BFD.  The problem, which is stabs specific, can
240     be identified by a bunch of failures in relocate.exp vis:
241
242       gdb.base/relocate.exp: get address of static_bar
243
244     Details of the problem can be found on the binutils@ mailing
245     list, see the discussion thread: "gdb.mi/mi-cli.exp failures".  */
246  if (storage_needed != 0)
247    free (symbol_table);
248#endif
249
250  sec->_cooked_size = old_cooked_size;
251  bfd_map_over_sections (abfd, simple_restore_output_info, saved_offsets);
252  free (saved_offsets);
253
254  _bfd_generic_link_hash_table_free (link_info.hash);
255
256  return contents;
257}
258