bfd/simple.c

   1 /* simple.c -- BFD simple client routines
   2    Copyright 2002, 2003, 2004, 2005, 2007
   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 = 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 = 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       bfd_size_type amt = sec->rawsize > sec->size ? sec->rawsize : sec->size;
 171       bfd_size_type size = sec->rawsize ? sec->rawsize : sec->size;
 172
 173       if (outbuf == NULL)
 174         contents = bfd_malloc (amt);
 175       else
 176         contents = outbuf;
 177
 178       if (contents)
 179         bfd_get_section_contents (abfd, sec, contents, 0, size);
 180
 181       return contents;
 182     }
 183
 184   /* In order to use bfd_get_relocated_section_contents, we need
 185      to forge some data structures that it expects.  */
 186
 187   /* Fill in the bare minimum number of fields for our purposes.  */
 188   memset (&link_info, 0, sizeof (link_info));
 189   link_info.input_bfds = abfd;
 190   link_info.input_bfds_tail = &abfd->link_next;
 191
 192   link_info.hash = _bfd_generic_link_hash_table_create (abfd);
 193   link_info.callbacks = &callbacks;
 194   callbacks.warning = simple_dummy_warning;
 195   callbacks.undefined_symbol = simple_dummy_undefined_symbol;
 196   callbacks.reloc_overflow = simple_dummy_reloc_overflow;
 197   callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
 198   callbacks.unattached_reloc = simple_dummy_unattached_reloc;
 199   callbacks.multiple_definition = simple_dummy_multiple_definition;
 200   callbacks.einfo = simple_dummy_einfo;
 201
 202   memset (&link_order, 0, sizeof (link_order));
 203   link_order.next = NULL;
 204   link_order.type = bfd_indirect_link_order;
 205   link_order.offset = 0;
 206   link_order.size = sec->size;
 207   link_order.u.indirect.section = sec;
 208
 209   data = NULL;
 210   if (outbuf == NULL)
 211     {
 212       data = bfd_malloc (sec->size);
 213       if (data == NULL)
 214         return NULL;
 215       outbuf = data;
 216     }
 217
 218   /* The sections in ABFD may already have output sections and offsets set.
 219      Because this function is primarily for debug sections, and GCC uses the
 220      knowledge that debug sections will generally have VMA 0 when emitting
 221      relocations between DWARF-2 sections (which are supposed to be
 222      section-relative offsets anyway), we need to reset the output offsets
 223      to zero.  We also need to arrange for section->output_section->vma plus
 224      section->output_offset to equal section->vma, which we do by setting
 225      section->output_section to point back to section.  Save the original
 226      output offset and output section to restore later.  */
 227   saved_offsets = malloc (sizeof (struct saved_output_info)
 228                           * abfd->section_count);
 229   if (saved_offsets == NULL)
 230     {
 231       if (data)
 232         free (data);
 233       return NULL;
 234     }
 235   bfd_map_over_sections (abfd, simple_save_output_info, saved_offsets);
 236
 237   if (symbol_table == NULL)
 238     {
 239       _bfd_generic_link_add_symbols (abfd, &link_info);
 240
 241       storage_needed = bfd_get_symtab_upper_bound (abfd);
 242       symbol_table = bfd_malloc (storage_needed);
 243       bfd_canonicalize_symtab (abfd, symbol_table);
 244     }
 245   else
 246     storage_needed = 0;
 247
 248   contents = bfd_get_relocated_section_contents (abfd,
 249                                                  &link_info,
 250                                                  &link_order,
 251                                                  outbuf,
 252                                                  0,
 253                                                  symbol_table);
 254   if (contents == NULL && data != NULL)
 255     free (data);
 256
 257   bfd_map_over_sections (abfd, simple_restore_output_info, saved_offsets);
 258   free (saved_offsets);
 259
 260   _bfd_generic_link_hash_table_free (link_info.hash);
 261   return contents;
 262 }