bfd/simple.c

   1 /* simple.c -- BFD simple client routines
   2    Copyright (C) 2002-2014 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
  27 static bfd_boolean
  28 simple_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
  38 static bfd_boolean
  39 simple_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
  49 static bfd_boolean
  50 simple_dummy_reloc_overflow (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  51                              struct bfd_link_hash_entry *entry ATTRIBUTE_UNUSED,
  52                              const char *name ATTRIBUTE_UNUSED,
  53                              const char *reloc_name ATTRIBUTE_UNUSED,
  54                              bfd_vma addend ATTRIBUTE_UNUSED,
  55                              bfd *abfd ATTRIBUTE_UNUSED,
  56                              asection *section ATTRIBUTE_UNUSED,
  57                              bfd_vma address ATTRIBUTE_UNUSED)
  58 {
  59   return TRUE;
  60 }
  61
  62 static bfd_boolean
  63 simple_dummy_reloc_dangerous (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  64                               const char *message ATTRIBUTE_UNUSED,
  65                               bfd *abfd ATTRIBUTE_UNUSED,
  66                               asection *section ATTRIBUTE_UNUSED,
  67                               bfd_vma address ATTRIBUTE_UNUSED)
  68 {
  69   return TRUE;
  70 }
  71
  72 static bfd_boolean
  73 simple_dummy_unattached_reloc (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  74                                const char *name ATTRIBUTE_UNUSED,
  75                                bfd *abfd ATTRIBUTE_UNUSED,
  76                                asection *section ATTRIBUTE_UNUSED,
  77                                bfd_vma address ATTRIBUTE_UNUSED)
  78 {
  79   return TRUE;
  80 }
  81
  82 static bfd_boolean
  83 simple_dummy_multiple_definition (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  84                                   struct bfd_link_hash_entry *h ATTRIBUTE_UNUSED,
  85                                   bfd *nbfd ATTRIBUTE_UNUSED,
  86                                   asection *nsec ATTRIBUTE_UNUSED,
  87                                   bfd_vma nval ATTRIBUTE_UNUSED)
  88 {
  89   return TRUE;
  90 }
  91
  92 static void
  93 simple_dummy_einfo (const char *fmt ATTRIBUTE_UNUSED, ...)
  94 {
  95 }
  96
  97 struct saved_output_info
  98 {
  99   bfd_vma offset;
 100   asection *section;
 101 };
 102
 103 struct saved_offsets
 104 {
 105   int section_count;
 106   struct saved_output_info *sections;
 107 };
 108
 109 /* The sections in ABFD may already have output sections and offsets
 110    set if we are here during linking.
 111
 112    DWARF-2 specifies offsets into debug sections in many cases and
 113    bfd_simple_get_relocated_section_contents is called to relocate
 114    debug info for a single relocatable object file.  So we want
 115    offsets relative to that object file's sections, not offsets in the
 116    output file.  For that reason, reset a debug section->output_offset
 117    to zero.
 118
 119    If not called during linking then set section->output_section to
 120    point back to the input section, because output_section must not be
 121    NULL when calling the relocation routines.
 122
 123    Save the original output offset and section to restore later.  */
 124
 125 static void
 126 simple_save_output_info (bfd *abfd ATTRIBUTE_UNUSED,
 127                          asection *section,
 128                          void *ptr)
 129 {
 130   struct saved_offsets *saved_offsets = (struct saved_offsets *) ptr;
 131   struct saved_output_info *output_info;
 132
 133   output_info = &saved_offsets->sections[section->index];
 134   output_info->offset = section->output_offset;
 135   output_info->section = section->output_section;
 136   if ((section->flags & SEC_DEBUGGING) != 0
 137       || section->output_section == NULL)
 138     {
 139       section->output_offset = 0;
 140       section->output_section = section;
 141     }
 142 }
 143
 144 static void
 145 simple_restore_output_info (bfd *abfd ATTRIBUTE_UNUSED,
 146                             asection *section,
 147                             void *ptr)
 148 {
 149   struct saved_offsets *saved_offsets = (struct saved_offsets *) ptr;
 150   struct saved_output_info *output_info;
 151
 152   if (section->index >= saved_offsets->section_count)
 153     return;
 154
 155   output_info = &saved_offsets->sections[section->index];
 156   section->output_offset = output_info->offset;
 157   section->output_section = output_info->section;
 158 }
 159
 160 /*
 161 FUNCTION
 162         bfd_simple_relocate_secton
 163
 164 SYNOPSIS
 165         bfd_byte *bfd_simple_get_relocated_section_contents
 166           (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
 167
 168 DESCRIPTION
 169         Returns the relocated contents of section @var{sec}.  The symbols in
 170         @var{symbol_table} will be used, or the symbols from @var{abfd} if
 171         @var{symbol_table} is NULL.  The output offsets for debug sections will
 172         be temporarily reset to 0.  The result will be stored at @var{outbuf}
 173         or allocated with @code{bfd_malloc} if @var{outbuf} is @code{NULL}.
 174
 175         Returns @code{NULL} on a fatal error; ignores errors applying
 176         particular relocations.
 177 */
 178
 179 bfd_byte *
 180 bfd_simple_get_relocated_section_contents (bfd *abfd,
 181                                            asection *sec,
 182                                            bfd_byte *outbuf,
 183                                            asymbol **symbol_table)
 184 {
 185   struct bfd_link_info link_info;
 186   struct bfd_link_order link_order;
 187   struct bfd_link_callbacks callbacks;
 188   bfd_byte *contents, *data;
 189   int storage_needed;
 190   struct saved_offsets saved_offsets;
 191
 192   /* Don't apply relocation on executable and shared library.  See
 193      PR 4756.  */
 194   if ((abfd->flags & (HAS_RELOC | EXEC_P | DYNAMIC)) != HAS_RELOC
 195       || ! (sec->flags & SEC_RELOC))
 196     {
 197       contents = outbuf;
 198       if (!bfd_get_full_section_contents (abfd, sec, &contents))
 199         return NULL;
 200       return contents;
 201     }
 202
 203   /* In order to use bfd_get_relocated_section_contents, we need
 204      to forge some data structures that it expects.  */
 205
 206   /* Fill in the bare minimum number of fields for our purposes.  */
 207   memset (&link_info, 0, sizeof (link_info));
 208   link_info.output_bfd = abfd;
 209   link_info.input_bfds = abfd;
 210   link_info.input_bfds_tail = &abfd->link_next;
 211
 212   link_info.hash = _bfd_generic_link_hash_table_create (abfd);
 213   link_info.callbacks = &callbacks;
 214   callbacks.warning = simple_dummy_warning;
 215   callbacks.undefined_symbol = simple_dummy_undefined_symbol;
 216   callbacks.reloc_overflow = simple_dummy_reloc_overflow;
 217   callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
 218   callbacks.unattached_reloc = simple_dummy_unattached_reloc;
 219   callbacks.multiple_definition = simple_dummy_multiple_definition;
 220   callbacks.einfo = simple_dummy_einfo;
 221
 222   memset (&link_order, 0, sizeof (link_order));
 223   link_order.next = NULL;
 224   link_order.type = bfd_indirect_link_order;
 225   link_order.offset = 0;
 226   link_order.size = sec->size;
 227   link_order.u.indirect.section = sec;
 228
 229   data = NULL;
 230   if (outbuf == NULL)
 231     {
 232       bfd_size_type amt = sec->rawsize > sec->size ? sec->rawsize : sec->size;
 233       data = (bfd_byte *) bfd_malloc (amt);
 234       if (data == NULL)
 235         return NULL;
 236       outbuf = data;
 237     }
 238
 239   saved_offsets.section_count = abfd->section_count;
 240   saved_offsets.sections = malloc (sizeof (*saved_offsets.sections)
 241                                    * saved_offsets.section_count);
 242   if (saved_offsets.sections == NULL)
 243     {
 244       if (data)
 245         free (data);
 246       return NULL;
 247     }
 248   bfd_map_over_sections (abfd, simple_save_output_info, &saved_offsets);
 249
 250   if (symbol_table == NULL)
 251     {
 252       _bfd_generic_link_add_symbols (abfd, &link_info);
 253
 254       storage_needed = bfd_get_symtab_upper_bound (abfd);
 255       symbol_table = (asymbol **) bfd_malloc (storage_needed);
 256       bfd_canonicalize_symtab (abfd, symbol_table);
 257     }
 258   else
 259     storage_needed = 0;
 260
 261   contents = bfd_get_relocated_section_contents (abfd,
 262                                                  &link_info,
 263                                                  &link_order,
 264                                                  outbuf,
 265                                                  0,
 266                                                  symbol_table);
 267   if (contents == NULL && data != NULL)
 268     free (data);
 269
 270   bfd_map_over_sections (abfd, simple_restore_output_info, &saved_offsets);
 271   free (saved_offsets.sections);
 272
 273   _bfd_generic_link_hash_table_free (link_info.hash);
 274   return contents;
 275 }