bfd/simple.c

   1 /* simple.c -- BFD simple client routines
   2    Copyright 2002, 2003, 2004
   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 2 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 #include "bfd.h"
  23 #include "sysdep.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                              const char *name ATTRIBUTE_UNUSED,
  52                              const char *reloc_name ATTRIBUTE_UNUSED,
  53                              bfd_vma addend ATTRIBUTE_UNUSED,
  54                              bfd *abfd ATTRIBUTE_UNUSED,
  55                              asection *section ATTRIBUTE_UNUSED,
  56                              bfd_vma address ATTRIBUTE_UNUSED)
  57 {
  58   return TRUE;
  59 }
  60
  61 static bfd_boolean
  62 simple_dummy_reloc_dangerous (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  63                               const char *message ATTRIBUTE_UNUSED,
  64                               bfd *abfd ATTRIBUTE_UNUSED,
  65                               asection *section ATTRIBUTE_UNUSED,
  66                               bfd_vma address ATTRIBUTE_UNUSED)
  67 {
  68   return TRUE;
  69 }
  70
  71 static bfd_boolean
  72 simple_dummy_unattached_reloc (struct bfd_link_info *link_info ATTRIBUTE_UNUSED,
  73                                const char *name ATTRIBUTE_UNUSED,
  74                                bfd *abfd ATTRIBUTE_UNUSED,
  75                                asection *section ATTRIBUTE_UNUSED,
  76                                bfd_vma address ATTRIBUTE_UNUSED)
  77 {
  78   return TRUE;
  79 }
  80
  81 struct saved_output_info
  82 {
  83   bfd_vma offset;
  84   asection *section;
  85 };
  86
  87 static void
  88 simple_save_output_info (bfd *abfd ATTRIBUTE_UNUSED,
  89                          asection *section,
  90                          void *ptr)
  91 {
  92   struct saved_output_info *output_info = ptr;
  93   output_info[section->index].offset = section->output_offset;
  94   output_info[section->index].section = section->output_section;
  95   section->output_offset = 0;
  96   section->output_section = section;
  97 }
  98
  99 static void
 100 simple_restore_output_info (bfd *abfd ATTRIBUTE_UNUSED,
 101                             asection *section,
 102                             void *ptr)
 103 {
 104   struct saved_output_info *output_info = ptr;
 105   section->output_offset = output_info[section->index].offset;
 106   section->output_section = output_info[section->index].section;
 107 }
 108
 109 /*
 110 FUNCTION
 111         bfd_simple_relocate_secton
 112
 113 SYNOPSIS
 114         bfd_byte *bfd_simple_get_relocated_section_contents
 115           (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
 116
 117 DESCRIPTION
 118         Returns the relocated contents of section @var{sec}.  The symbols in
 119         @var{symbol_table} will be used, or the symbols from @var{abfd} if
 120         @var{symbol_table} is NULL.  The output offsets for all sections will
 121         be temporarily reset to 0.  The result will be stored at @var{outbuf}
 122         or allocated with @code{bfd_malloc} if @var{outbuf} is @code{NULL}.
 123
 124         Generally all sections in @var{abfd} should have their
 125         @code{output_section} pointing back to the original section.
 126
 127         Returns @code{NULL} on a fatal error; ignores errors applying
 128         particular relocations.
 129 */
 130
 131 bfd_byte *
 132 bfd_simple_get_relocated_section_contents (bfd *abfd,
 133                                            asection *sec,
 134                                            bfd_byte *outbuf,
 135                                            asymbol **symbol_table)
 136 {
 137   struct bfd_link_info link_info;
 138   struct bfd_link_order link_order;
 139   struct bfd_link_callbacks callbacks;
 140   bfd_byte *contents, *data;
 141   int storage_needed;
 142   void *saved_offsets;
 143   bfd_size_type old_cooked_size;
 144
 145   if (! (sec->flags & SEC_RELOC))
 146     {
 147       bfd_size_type size = bfd_section_size (abfd, sec);
 148
 149       if (outbuf == NULL)
 150         contents = bfd_malloc (size);
 151       else
 152         contents = outbuf;
 153
 154       if (contents)
 155         bfd_get_section_contents (abfd, sec, contents, 0, size);
 156
 157       return contents;
 158     }
 159
 160   /* In order to use bfd_get_relocated_section_contents, we need
 161      to forge some data structures that it expects.  */
 162
 163   /* Fill in the bare minimum number of fields for our purposes.  */
 164   memset (&link_info, 0, sizeof (link_info));
 165   link_info.input_bfds = abfd;
 166
 167   link_info.hash = _bfd_generic_link_hash_table_create (abfd);
 168   link_info.callbacks = &callbacks;
 169   callbacks.warning = simple_dummy_warning;
 170   callbacks.undefined_symbol = simple_dummy_undefined_symbol;
 171   callbacks.reloc_overflow = simple_dummy_reloc_overflow;
 172   callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
 173   callbacks.unattached_reloc = simple_dummy_unattached_reloc;
 174
 175   memset (&link_order, 0, sizeof (link_order));
 176   link_order.next = NULL;
 177   link_order.type = bfd_indirect_link_order;
 178   link_order.offset = 0;
 179   link_order.size = bfd_section_size (abfd, sec);
 180   link_order.u.indirect.section = sec;
 181
 182   data = NULL;
 183   if (outbuf == NULL)
 184     {
 185       data = bfd_malloc (bfd_section_size (abfd, sec));
 186       if (data == NULL)
 187         return NULL;
 188       outbuf = data;
 189     }
 190
 191   /* The sections in ABFD may already have output sections and offsets set.
 192      Because this function is primarily for debug sections, and GCC uses the
 193      knowledge that debug sections will generally have VMA 0 when emitting
 194      relocations between DWARF-2 sections (which are supposed to be
 195      section-relative offsets anyway), we need to reset the output offsets
 196      to zero.  We also need to arrange for section->output_section->vma plus
 197      section->output_offset to equal section->vma, which we do by setting
 198      section->output_section to point back to section.  Save the original
 199      output offset and output section to restore later.  */
 200   saved_offsets = malloc (sizeof (struct saved_output_info)
 201                           * abfd->section_count);
 202   if (saved_offsets == NULL)
 203     {
 204       if (data)
 205         free (data);
 206       return NULL;
 207     }
 208   bfd_map_over_sections (abfd, simple_save_output_info, saved_offsets);
 209
 210   if (symbol_table == NULL)
 211     {
 212       _bfd_generic_link_add_symbols (abfd, &link_info);
 213
 214       storage_needed = bfd_get_symtab_upper_bound (abfd);
 215       symbol_table = bfd_malloc (storage_needed);
 216       bfd_canonicalize_symtab (abfd, symbol_table);
 217     }
 218   else
 219     storage_needed = 0;
 220
 221   /* This function might be called before _cooked_size has been set, and
 222      bfd_perform_relocation needs _cooked_size to be valid.  */
 223   old_cooked_size = sec->_cooked_size;
 224   if (old_cooked_size == 0)
 225     sec->_cooked_size = sec->_raw_size;
 226
 227   contents = bfd_get_relocated_section_contents (abfd,
 228                                                  &link_info,
 229                                                  &link_order,
 230                                                  outbuf,
 231                                                  0,
 232                                                  symbol_table);
 233   if (contents == NULL && data != NULL)
 234     free (data);
 235
 236 #if 0
 237   /* NOTE: cagney/2003-04-05: This free, which was introduced on
 238      2003-03-31 to stop a memory leak, caused a memory corruption
 239      between GDB and BFD.  The problem, which is stabs specific, can
 240      be identified by a bunch of failures in relocate.exp vis:
 241
 242        gdb.base/relocate.exp: get address of static_bar
 243
 244      Details of the problem can be found on the binutils@ mailing
 245      list, see the discussion thread: "gdb.mi/mi-cli.exp failures".  */
 246   if (storage_needed != 0)
 247     free (symbol_table);
 248 #endif
 249
 250   sec->_cooked_size = old_cooked_size;
 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
 256   return contents;
 257 }