bfd/simple.c

   1 /* simple.c -- BFD simple client routines
   2    Copyright 2002, 2003
   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
 144   if (! (sec->flags & SEC_RELOC))
 145     {
 146       bfd_size_type size = bfd_section_size (abfd, sec);
 147
 148       if (outbuf == NULL)
 149         contents = bfd_malloc (size);
 150       else
 151         contents = outbuf;
 152
 153       if (contents)
 154         bfd_get_section_contents (abfd, sec, contents, 0, size);
 155
 156       return contents;
 157     }
 158
 159   /* In order to use bfd_get_relocated_section_contents, we need
 160      to forge some data structures that it expects.  */
 161
 162   /* Fill in the bare minimum number of fields for our purposes.  */
 163   memset (&link_info, 0, sizeof (link_info));
 164   link_info.input_bfds = abfd;
 165
 166   link_info.hash = bfd_link_hash_table_create (abfd);
 167   link_info.callbacks = &callbacks;
 168   callbacks.warning = simple_dummy_warning;
 169   callbacks.undefined_symbol = simple_dummy_undefined_symbol;
 170   callbacks.reloc_overflow = simple_dummy_reloc_overflow;
 171   callbacks.reloc_dangerous = simple_dummy_reloc_dangerous;
 172   callbacks.unattached_reloc = simple_dummy_unattached_reloc;
 173
 174   memset (&link_order, 0, sizeof (link_order));
 175   link_order.next = NULL;
 176   link_order.type = bfd_indirect_link_order;
 177   link_order.offset = 0;
 178   link_order.size = bfd_section_size (abfd, sec);
 179   link_order.u.indirect.section = sec;
 180
 181   data = NULL;
 182   if (outbuf == NULL)
 183     {
 184       data = bfd_malloc (bfd_section_size (abfd, sec));
 185       if (data == NULL)
 186         return NULL;
 187       outbuf = data;
 188     }
 189
 190   /* The sections in ABFD may already have output sections and offsets set.
 191      Because this function is primarily for debug sections, and GCC uses the
 192      knowledge that debug sections will generally have VMA 0 when emiting
 193      relocations between DWARF-2 sections (which are supposed to be
 194      section-relative offsets anyway), we need to reset the output offsets
 195      to zero.  We also need to arrange for section->output_section->vma plus
 196      section->output_offset to equal section->vma, which we do by setting
 197      section->output_section to point back to section.  Save the original
 198      output offset and output section to restore later.  */
 199   saved_offsets = malloc (sizeof (struct saved_output_info)
 200                           * abfd->section_count);
 201   if (saved_offsets == NULL)
 202     {
 203       if (data)
 204         free (data);
 205       return NULL;
 206     }
 207   bfd_map_over_sections (abfd, simple_save_output_info, saved_offsets);
 208
 209   if (symbol_table == NULL)
 210     {
 211       _bfd_generic_link_add_symbols (abfd, &link_info);
 212
 213       storage_needed = bfd_get_symtab_upper_bound (abfd);
 214       symbol_table = bfd_malloc (storage_needed);
 215       bfd_canonicalize_symtab (abfd, symbol_table);
 216     }
 217   else
 218     storage_needed = 0;
 219
 220   contents = bfd_get_relocated_section_contents (abfd,
 221                                                  &link_info,
 222                                                  &link_order,
 223                                                  outbuf,
 224                                                  0,
 225                                                  symbol_table);
 226   if (contents == NULL && data != NULL)
 227     free (data);
 228
 229 #if 0
 230   /* NOTE: cagney/2003-04-05: This free, which was introduced on
 231      2003-03-31 to stop a memory leak, caused a memory corruption
 232      between GDB and BFD.  The problem, which is stabs specific, can
 233      be identified by a bunch of failures in relocate.exp vis:
 234
 235        gdb.base/relocate.exp: get address of static_bar
 236
 237      Details of the problem can be found on the binutils@ mailing
 238      list, see the discussion thread: "gdb.mi/mi-cli.exp failures".  */
 239   if (storage_needed != 0)
 240     free (symbol_table);
 241 #endif
 242
 243   bfd_map_over_sections (abfd, simple_restore_output_info, saved_offsets);
 244   free (saved_offsets);
 245
 246   /* Foul hack to prevent bfd_section_size aborts.  This flag only controls
 247      that macro (and the related size macros), selecting between _raw_size
 248      and _cooked_size.  Debug sections won't change size while we're only
 249      relocating.  There may be trouble here someday if it tries to run
 250      relaxation unexpectedly, so make sure.  */
 251   BFD_ASSERT (sec->_raw_size == sec->_cooked_size);
 252   sec->reloc_done = 0;
 253
 254   bfd_link_hash_table_free (abfd, link_info.hash);
 255
 256   return contents;
 257 }