bfd/simple.c

   1 /* simple.c -- BFD simple client routines
   2    Copyright 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
   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 3 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., 51 Franklin Street - Fifth Floor, Boston,
  21    MA 02110-1301, USA.  */
  22
  23 #include "sysdep.h"
  24 #include "bfd.h"
  25 #include "libbfd.h"
  26 #include "bfdlink.h"
  27
  28 static bfd_boolean
  29 simple_dummy_warning (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  30                       const char *warning ATTRIBUTE_UNUSED,
  31                       const char *symbol ATTRIBUTE_UNUSED,
  32                       bfd *abfd ATTRIBUTE_UNUSED,
  33                       asection *section ATTRIBUTE_UNUSED,
  34                       bfd_vma address ATTRIBUTE_UNUSED)
  35 {
  36   return TRUE;
  37 }
  38
  39 static bfd_boolean
  40 simple_dummy_undefined_symbol (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  41                                const char *name ATTRIBUTE_UNUSED,
  42                                bfd *abfd ATTRIBUTE_UNUSED,
  43                                asection *section ATTRIBUTE_UNUSED,
  44                                bfd_vma address ATTRIBUTE_UNUSED,
  45                                bfd_boolean fatal ATTRIBUTE_UNUSED)
  46 {
  47   return TRUE;
  48 }
  49
  50 static bfd_boolean
  51 simple_dummy_reloc_overflow (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  52                              struct bfd_link_hash_entry *entry ATTRIBUTE_UNUSED,
  53                              const char *name ATTRIBUTE_UNUSED,
  54                              const char *reloc_name ATTRIBUTE_UNUSED,
  55                              bfd_vma addend ATTRIBUTE_UNUSED,
  56                              bfd *abfd ATTRIBUTE_UNUSED,
  57                              asection *section ATTRIBUTE_UNUSED,
  58                              bfd_vma address ATTRIBUTE_UNUSED)
  59 {
  60   return TRUE;
  61 }
  62
  63 static bfd_boolean
  64 simple_dummy_reloc_dangerous (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  65                               const char *message ATTRIBUTE_UNUSED,
  66                               bfd *abfd ATTRIBUTE_UNUSED,
  67                               asection *section ATTRIBUTE_UNUSED,
  68                               bfd_vma address ATTRIBUTE_UNUSED)
  69 {
  70   return TRUE;
  71 }
  72
  73 static bfd_boolean
  74 simple_dummy_unattached_reloc (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  75                                const char *name ATTRIBUTE_UNUSED,
  76                                bfd *abfd ATTRIBUTE_UNUSED,
  77                                asection *section ATTRIBUTE_UNUSED,
  78                                bfd_vma address ATTRIBUTE_UNUSED)
  79 {
  80   return TRUE;
  81 }
  82
  83 static bfd_boolean
  84 simple_dummy_multiple_definition (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  85                                   struct bfd_link_hash_entry *h ATTRIBUTE_UNUSED,
  86                                   bfd *nbfd ATTRIBUTE_UNUSED,
  87                                   asection *nsec ATTRIBUTE_UNUSED,
  88                                   bfd_vma nval ATTRIBUTE_UNUSED)
  89 {
  90   return TRUE;
  91 }
  92
  93 static void
  94 simple_dummy_einfo (const char *fmt ATTRIBUTE_UNUSED, ...)
  95 {
  96 }
  97
  98 struct saved_output_info
  99 {
 100   bfd_vma offset;
 101   asection *section;
 102 };
 103
 104 struct saved_offsets
 105 {
 106   int section_count;
 107   struct saved_output_info *sections;
 108 };
 109
 110 static void
 111 simple_save_output_info (bfd *abfd ATTRIBUTE_UNUSED,
 112                          asection *section,
 113                          void *ptr)
 114 {
 115   struct saved_offsets *saved_offsets = (struct saved_offsets *) ptr;
 116   struct saved_output_info *output_info;
 117
 118   output_info = &saved_offsets->sections[section->index];
 119   output_info->offset = section->output_offset;
 120   output_info->section = section->output_section;
 121   if ((section->flags & SEC_DEBUGGING) != 0
 122       || section->output_section == NULL)
 123     {
 124       section->output_offset = 0;
 125       section->output_section = section;
 126     }
 127 }
 128
 129 static void
 130 simple_restore_output_info (bfd *abfd ATTRIBUTE_UNUSED,
 131                             asection *section,
 132                             void *ptr)
 133 {
 134   struct saved_offsets *saved_offsets = (struct saved_offsets *) ptr;
 135   struct saved_output_info *output_info;
 136
 137   if (section->index >= saved_offsets->section_count)
 138     return;
 139
 140   output_info = &saved_offsets->sections[section->index];
 141   section->output_offset = output_info->offset;
 142   section->output_section = output_info->section;
 143 }
 144
 145 /*
 146 FUNCTION
 147         bfd_simple_relocate_secton
 148
 149 SYNOPSIS
 150         bfd_byte *bfd_simple_get_relocated_section_contents
 151           (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
 152
 153 DESCRIPTION
 154         Returns the relocated contents of section @var{sec}.  The symbols in
 155         @var{symbol_table} will be used, or the symbols from @var{abfd} if
 156         @var{symbol_table} is NULL.  The output offsets for debug sections will
 157         be temporarily reset to 0.  The result will be stored at @var{outbuf}
 158         or allocated with @code{bfd_malloc} if @var{outbuf} is @code{NULL}.
 159
 160         Returns @code{NULL} on a fatal error; ignores errors applying
 161         particular relocations.
 162 */
 163
 164 bfd_byte *
 165 bfd_simple_get_relocated_section_contents (bfd *abfd,
 166                                            asection *sec,
 167                                            bfd_byte *outbuf,
 168                                            asymbol **symbol_table)
 169 {
 170   struct bfd_link_info link_info;
 171   struct bfd_link_order link_order;
 172   struct bfd_link_callbacks callbacks;
 173   bfd_byte *contents, *data;
 174   int storage_needed;
 175   struct saved_offsets saved_offsets;
 176
 177   /* Don't apply relocation on executable and shared library.  See
 178      PR 4756.  */
 179   if ((abfd->flags & (HAS_RELOC | EXEC_P | DYNAMIC)) != HAS_RELOC
 180       || ! (sec->flags & SEC_RELOC))
 181     {
 182       contents = outbuf;
 183       if (!bfd_get_full_section_contents (abfd, sec, &contents))
 184         return NULL;
 185       return contents;
 186     }
 187
 188   /* In order to use bfd_get_relocated_section_contents, we need
 189      to forge some data structures that it expects.  */
 190
 191   /* Fill in the bare minimum number of fields for our purposes.  */
 192   memset (&link_info, 0, sizeof (link_info));
 193   link_info.output_bfd = abfd;
 194   link_info.input_bfds = abfd;
 195   link_info.input_bfds_tail = &abfd->link_next;
 196
 197   link_info.hash = _bfd_generic_link_hash_table_create (abfd);
 198   link_info.callbacks = &callbacks;
 199   callbacks.warning = simple_dummy_warning;
 200   callbacks.undefined_symbol = simple_dummy_undefined_symbol;
 201   callbacks.reloc_overflow = simple_dummy_reloc_overflow;
 202   callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
 203   callbacks.unattached_reloc = simple_dummy_unattached_reloc;
 204   callbacks.multiple_definition = simple_dummy_multiple_definition;
 205   callbacks.einfo = simple_dummy_einfo;
 206
 207   memset (&link_order, 0, sizeof (link_order));
 208   link_order.next = NULL;
 209   link_order.type = bfd_indirect_link_order;
 210   link_order.offset = 0;
 211   link_order.size = sec->size;
 212   link_order.u.indirect.section = sec;
 213
 214   data = NULL;
 215   if (outbuf == NULL)
 216     {
 217       bfd_size_type amt = sec->rawsize > sec->size ? sec->rawsize : sec->size;
 218       data = (bfd_byte *) bfd_malloc (amt);
 219       if (data == NULL)
 220         return NULL;
 221       outbuf = data;
 222     }
 223
 224   /* The sections in ABFD may already have output sections and offsets set.
 225      Because this function is primarily for debug sections, and GCC uses the
 226      knowledge that debug sections will generally have VMA 0 when emitting
 227      relocations between DWARF-2 sections (which are supposed to be
 228      section-relative offsets anyway), we need to reset the output offsets
 229      to zero.  We also need to arrange for section->output_section->vma plus
 230      section->output_offset to equal section->vma, which we do by setting
 231      section->output_section to point back to section.  Save the original
 232      output offset and output section to restore later.  */
 233   saved_offsets.section_count = abfd->section_count;
 234   saved_offsets.sections = malloc (sizeof (*saved_offsets.sections)
 235                                    * saved_offsets.section_count);
 236   if (saved_offsets.sections == NULL)
 237     {
 238       if (data)
 239         free (data);
 240       return NULL;
 241     }
 242   bfd_map_over_sections (abfd, simple_save_output_info, &saved_offsets);
 243
 244   if (symbol_table == NULL)
 245     {
 246       _bfd_generic_link_add_symbols (abfd, &link_info);
 247
 248       storage_needed = bfd_get_symtab_upper_bound (abfd);
 249       symbol_table = (asymbol **) bfd_malloc (storage_needed);
 250       bfd_canonicalize_symtab (abfd, symbol_table);
 251     }
 252   else
 253     storage_needed = 0;
 254
 255   contents = bfd_get_relocated_section_contents (abfd,
 256                                                  &link_info,
 257                                                  &link_order,
 258                                                  outbuf,
 259                                                  0,
 260                                                  symbol_table);
 261   if (contents == NULL && data != NULL)
 262     free (data);
 263
 264   bfd_map_over_sections (abfd, simple_restore_output_info, &saved_offsets);
 265   free (saved_offsets.sections);
 266
 267   _bfd_generic_link_hash_table_free (link_info.hash);
 268   return contents;
 269 }