bfd/simple.c

   1 /* simple.c -- BFD simple client routines
   2    Copyright 2002, 2003, 2004, 2005, 2007, 2008, 2009
   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                                   const char *name ATTRIBUTE_UNUSED,
  86                                   bfd *obfd ATTRIBUTE_UNUSED,
  87                                   asection *osec ATTRIBUTE_UNUSED,
  88                                   bfd_vma oval ATTRIBUTE_UNUSED,
  89                                   bfd *nbfd ATTRIBUTE_UNUSED,
  90                                   asection *nsec ATTRIBUTE_UNUSED,
  91                                   bfd_vma nval ATTRIBUTE_UNUSED)
  92 {
  93   return TRUE;
  94 }
  95
  96 static void
  97 simple_dummy_einfo (const char *fmt ATTRIBUTE_UNUSED, ...)
  98 {
  99 }
 100
 101 struct saved_output_info
 102 {
 103   bfd_vma offset;
 104   asection *section;
 105 };
 106
 107 static void
 108 simple_save_output_info (bfd *abfd ATTRIBUTE_UNUSED,
 109                          asection *section,
 110                          void *ptr)
 111 {
 112   struct saved_output_info *output_info = (struct saved_output_info *) ptr;
 113   output_info[section->index].offset = section->output_offset;
 114   output_info[section->index].section = section->output_section;
 115   if ((section->flags & SEC_DEBUGGING) != 0
 116       || section->output_section == NULL)
 117     {
 118       section->output_offset = 0;
 119       section->output_section = section;
 120     }
 121 }
 122
 123 static void
 124 simple_restore_output_info (bfd *abfd ATTRIBUTE_UNUSED,
 125                             asection *section,
 126                             void *ptr)
 127 {
 128   struct saved_output_info *output_info = (struct saved_output_info *) ptr;
 129   section->output_offset = output_info[section->index].offset;
 130   section->output_section = output_info[section->index].section;
 131 }
 132
 133 /*
 134 FUNCTION
 135         bfd_simple_relocate_secton
 136
 137 SYNOPSIS
 138         bfd_byte *bfd_simple_get_relocated_section_contents
 139           (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
 140
 141 DESCRIPTION
 142         Returns the relocated contents of section @var{sec}.  The symbols in
 143         @var{symbol_table} will be used, or the symbols from @var{abfd} if
 144         @var{symbol_table} is NULL.  The output offsets for debug sections will
 145         be temporarily reset to 0.  The result will be stored at @var{outbuf}
 146         or allocated with @code{bfd_malloc} if @var{outbuf} is @code{NULL}.
 147
 148         Returns @code{NULL} on a fatal error; ignores errors applying
 149         particular relocations.
 150 */
 151
 152 bfd_byte *
 153 bfd_simple_get_relocated_section_contents (bfd *abfd,
 154                                            asection *sec,
 155                                            bfd_byte *outbuf,
 156                                            asymbol **symbol_table)
 157 {
 158   struct bfd_link_info link_info;
 159   struct bfd_link_order link_order;
 160   struct bfd_link_callbacks callbacks;
 161   bfd_byte *contents, *data;
 162   int storage_needed;
 163   void *saved_offsets;
 164
 165   /* Don't apply relocation on executable and shared library.  See
 166      PR 4756.  */
 167   if ((abfd->flags & (HAS_RELOC | EXEC_P | DYNAMIC)) != HAS_RELOC
 168       || ! (sec->flags & SEC_RELOC))
 169     {
 170       contents = outbuf;
 171       if (!bfd_get_full_section_contents (abfd, sec, &contents))
 172         return NULL;
 173       return contents;
 174     }
 175
 176   /* In order to use bfd_get_relocated_section_contents, we need
 177      to forge some data structures that it expects.  */
 178
 179   /* Fill in the bare minimum number of fields for our purposes.  */
 180   memset (&link_info, 0, sizeof (link_info));
 181   link_info.output_bfd = abfd;
 182   link_info.input_bfds = abfd;
 183   link_info.input_bfds_tail = &abfd->link_next;
 184
 185   link_info.hash = _bfd_generic_link_hash_table_create (abfd);
 186   link_info.callbacks = &callbacks;
 187   callbacks.warning = simple_dummy_warning;
 188   callbacks.undefined_symbol = simple_dummy_undefined_symbol;
 189   callbacks.reloc_overflow = simple_dummy_reloc_overflow;
 190   callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
 191   callbacks.unattached_reloc = simple_dummy_unattached_reloc;
 192   callbacks.multiple_definition = simple_dummy_multiple_definition;
 193   callbacks.einfo = simple_dummy_einfo;
 194
 195   memset (&link_order, 0, sizeof (link_order));
 196   link_order.next = NULL;
 197   link_order.type = bfd_indirect_link_order;
 198   link_order.offset = 0;
 199   link_order.size = sec->size;
 200   link_order.u.indirect.section = sec;
 201
 202   data = NULL;
 203   if (outbuf == NULL)
 204     {
 205       bfd_size_type amt = sec->rawsize > sec->size ? sec->rawsize : sec->size;
 206       data = (bfd_byte *) bfd_malloc (amt);
 207       if (data == NULL)
 208         return NULL;
 209       outbuf = data;
 210     }
 211
 212   /* The sections in ABFD may already have output sections and offsets set.
 213      Because this function is primarily for debug sections, and GCC uses the
 214      knowledge that debug sections will generally have VMA 0 when emitting
 215      relocations between DWARF-2 sections (which are supposed to be
 216      section-relative offsets anyway), we need to reset the output offsets
 217      to zero.  We also need to arrange for section->output_section->vma plus
 218      section->output_offset to equal section->vma, which we do by setting
 219      section->output_section to point back to section.  Save the original
 220      output offset and output section to restore later.  */
 221   saved_offsets = malloc (sizeof (struct saved_output_info)
 222                           * abfd->section_count);
 223   if (saved_offsets == NULL)
 224     {
 225       if (data)
 226         free (data);
 227       return NULL;
 228     }
 229   bfd_map_over_sections (abfd, simple_save_output_info, saved_offsets);
 230
 231   if (symbol_table == NULL)
 232     {
 233       _bfd_generic_link_add_symbols (abfd, &link_info);
 234
 235       storage_needed = bfd_get_symtab_upper_bound (abfd);
 236       symbol_table = (asymbol **) bfd_malloc (storage_needed);
 237       bfd_canonicalize_symtab (abfd, symbol_table);
 238     }
 239   else
 240     storage_needed = 0;
 241
 242   contents = bfd_get_relocated_section_contents (abfd,
 243                                                  &link_info,
 244                                                  &link_order,
 245                                                  outbuf,
 246                                                  0,
 247                                                  symbol_table);
 248   if (contents == NULL && data != NULL)
 249     free (data);
 250
 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   return contents;
 256 }