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 static void
 110 simple_save_output_info (bfd *abfd ATTRIBUTE_UNUSED,
 111                          asection *section,
 112                          void *ptr)
 113 {
 114   struct saved_offsets *saved_offsets = (struct saved_offsets *) ptr;
 115   struct saved_output_info *output_info;
 116
 117   output_info = &saved_offsets->sections[section->index];
 118   output_info->offset = section->output_offset;
 119   output_info->section = section->output_section;
 120   if ((section->flags & SEC_DEBUGGING) != 0
 121       || section->output_section == NULL)
 122     {
 123       section->output_offset = 0;
 124       section->output_section = section;
 125     }
 126 }
 127
 128 static void
 129 simple_restore_output_info (bfd *abfd ATTRIBUTE_UNUSED,
 130                             asection *section,
 131                             void *ptr)
 132 {
 133   struct saved_offsets *saved_offsets = (struct saved_offsets *) ptr;
 134   struct saved_output_info *output_info;
 135
 136   if (section->index >= saved_offsets->section_count)
 137     return;
 138
 139   output_info = &saved_offsets->sections[section->index];
 140   section->output_offset = output_info->offset;
 141   section->output_section = output_info->section;
 142 }
 143
 144 /*
 145 FUNCTION
 146         bfd_simple_relocate_secton
 147
 148 SYNOPSIS
 149         bfd_byte *bfd_simple_get_relocated_section_contents
 150           (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
 151
 152 DESCRIPTION
 153         Returns the relocated contents of section @var{sec}.  The symbols in
 154         @var{symbol_table} will be used, or the symbols from @var{abfd} if
 155         @var{symbol_table} is NULL.  The output offsets for debug sections will
 156         be temporarily reset to 0.  The result will be stored at @var{outbuf}
 157         or allocated with @code{bfd_malloc} if @var{outbuf} is @code{NULL}.
 158
 159         Returns @code{NULL} on a fatal error; ignores errors applying
 160         particular relocations.
 161 */
 162
 163 bfd_byte *
 164 bfd_simple_get_relocated_section_contents (bfd *abfd,
 165                                            asection *sec,
 166                                            bfd_byte *outbuf,
 167                                            asymbol **symbol_table)
 168 {
 169   struct bfd_link_info link_info;
 170   struct bfd_link_order link_order;
 171   struct bfd_link_callbacks callbacks;
 172   bfd_byte *contents, *data;
 173   int storage_needed;
 174   struct saved_offsets saved_offsets;
 175
 176   /* Don't apply relocation on executable and shared library.  See
 177      PR 4756.  */
 178   if ((abfd->flags & (HAS_RELOC | EXEC_P | DYNAMIC)) != HAS_RELOC
 179       || ! (sec->flags & SEC_RELOC))
 180     {
 181       contents = outbuf;
 182       if (!bfd_get_full_section_contents (abfd, sec, &contents))
 183         return NULL;
 184       return contents;
 185     }
 186
 187   /* In order to use bfd_get_relocated_section_contents, we need
 188      to forge some data structures that it expects.  */
 189
 190   /* Fill in the bare minimum number of fields for our purposes.  */
 191   memset (&link_info, 0, sizeof (link_info));
 192   link_info.output_bfd = abfd;
 193   link_info.input_bfds = abfd;
 194   link_info.input_bfds_tail = &abfd->link_next;
 195
 196   link_info.hash = _bfd_generic_link_hash_table_create (abfd);
 197   link_info.callbacks = &callbacks;
 198   callbacks.warning = simple_dummy_warning;
 199   callbacks.undefined_symbol = simple_dummy_undefined_symbol;
 200   callbacks.reloc_overflow = simple_dummy_reloc_overflow;
 201   callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
 202   callbacks.unattached_reloc = simple_dummy_unattached_reloc;
 203   callbacks.multiple_definition = simple_dummy_multiple_definition;
 204   callbacks.einfo = simple_dummy_einfo;
 205
 206   memset (&link_order, 0, sizeof (link_order));
 207   link_order.next = NULL;
 208   link_order.type = bfd_indirect_link_order;
 209   link_order.offset = 0;
 210   link_order.size = sec->size;
 211   link_order.u.indirect.section = sec;
 212
 213   data = NULL;
 214   if (outbuf == NULL)
 215     {
 216       bfd_size_type amt = sec->rawsize > sec->size ? sec->rawsize : sec->size;
 217       data = (bfd_byte *) bfd_malloc (amt);
 218       if (data == NULL)
 219         return NULL;
 220       outbuf = data;
 221     }
 222
 223   /* The sections in ABFD may already have output sections and offsets set.
 224      Because this function is primarily for debug sections, and GCC uses the
 225      knowledge that debug sections will generally have VMA 0 when emitting
 226      relocations between DWARF-2 sections (which are supposed to be
 227      section-relative offsets anyway), we need to reset the output offsets
 228      to zero.  We also need to arrange for section->output_section->vma plus
 229      section->output_offset to equal section->vma, which we do by setting
 230      section->output_section to point back to section.  Save the original
 231      output offset and output section to restore later.  */
 232   saved_offsets.section_count = abfd->section_count;
 233   saved_offsets.sections = malloc (sizeof (*saved_offsets.sections)
 234                                    * saved_offsets.section_count);
 235   if (saved_offsets.sections == NULL)
 236     {
 237       if (data)
 238         free (data);
 239       return NULL;
 240     }
 241   bfd_map_over_sections (abfd, simple_save_output_info, &saved_offsets);
 242
 243   if (symbol_table == NULL)
 244     {
 245       _bfd_generic_link_add_symbols (abfd, &link_info);
 246
 247       storage_needed = bfd_get_symtab_upper_bound (abfd);
 248       symbol_table = (asymbol **) bfd_malloc (storage_needed);
 249       bfd_canonicalize_symtab (abfd, symbol_table);
 250     }
 251   else
 252     storage_needed = 0;
 253
 254   contents = bfd_get_relocated_section_contents (abfd,
 255                                                  &link_info,
 256                                                  &link_order,
 257                                                  outbuf,
 258                                                  0,
 259                                                  symbol_table);
 260   if (contents == NULL && data != NULL)
 261     free (data);
 262
 263   bfd_map_over_sections (abfd, simple_restore_output_info, &saved_offsets);
 264   free (saved_offsets.sections);
 265
 266   _bfd_generic_link_hash_table_free (link_info.hash);
 267   return contents;
 268 }