bfd/binary.c

   1 /* BFD back-end for binary objects.
   2    Copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
   3    2004, 2005, 2006, 2007, 2009 Free Software Foundation, Inc.
   4    Written by Ian Lance Taylor, Cygnus Support, <ian@cygnus.com>
   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 /* This is a BFD backend which may be used to write binary objects.
  24    It may only be used for output, not input.  The intention is that
  25    this may be used as an output format for objcopy in order to
  26    generate raw binary data.
  27
  28    This is very simple.  The only complication is that the real data
  29    will start at some address X, and in some cases we will not want to
  30    include X zeroes just to get to that point.  Since the start
  31    address is not meaningful for this object file format, we use it
  32    instead to indicate the number of zeroes to skip at the start of
  33    the file.  objcopy cooperates by specially setting the start
  34    address to zero by default.  */
  35
  36 #include "sysdep.h"
  37 #include "bfd.h"
  38 #include "safe-ctype.h"
  39 #include "libbfd.h"
  40
  41 /* Any bfd we create by reading a binary file has three symbols:
  42    a start symbol, an end symbol, and an absolute length symbol.  */
  43 #define BIN_SYMS 3
  44
  45 /* Create a binary object.  Invoked via bfd_set_format.  */
  46
  47 static bfd_boolean
  48 binary_mkobject (bfd *abfd ATTRIBUTE_UNUSED)
  49 {
  50   return TRUE;
  51 }
  52
  53 /* Any file may be considered to be a binary file, provided the target
  54    was not defaulted.  That is, it must be explicitly specified as
  55    being binary.  */
  56
  57 static const bfd_target *
  58 binary_object_p (bfd *abfd)
  59 {
  60   struct stat statbuf;
  61   asection *sec;
  62   flagword flags;
  63
  64   if (abfd->target_defaulted)
  65     {
  66       bfd_set_error (bfd_error_wrong_format);
  67       return NULL;
  68     }
  69
  70   abfd->symcount = BIN_SYMS;
  71
  72   /* Find the file size.  */
  73   if (bfd_stat (abfd, &statbuf) < 0)
  74     {
  75       bfd_set_error (bfd_error_system_call);
  76       return NULL;
  77     }
  78
  79   /* One data section.  */
  80   flags = SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS;
  81   sec = bfd_make_section_with_flags (abfd, ".data", flags);
  82   if (sec == NULL)
  83     return NULL;
  84   sec->vma = 0;
  85   sec->size = statbuf.st_size;
  86   sec->filepos = 0;
  87
  88   abfd->tdata.any = (void *) sec;
  89
  90   return abfd->xvec;
  91 }
  92
  93 #define binary_close_and_cleanup     _bfd_generic_close_and_cleanup
  94 #define binary_bfd_free_cached_info  _bfd_generic_bfd_free_cached_info
  95 #define binary_new_section_hook      _bfd_generic_new_section_hook
  96
  97 /* Get contents of the only section.  */
  98
  99 static bfd_boolean
 100 binary_get_section_contents (bfd *abfd,
 101                              asection *section ATTRIBUTE_UNUSED,
 102                              void * location,
 103                              file_ptr offset,
 104                              bfd_size_type count)
 105 {
 106   if (bfd_seek (abfd, offset, SEEK_SET) != 0
 107       || bfd_bread (location, count, abfd) != count)
 108     return FALSE;
 109   return TRUE;
 110 }
 111
 112 /* Return the amount of memory needed to read the symbol table.  */
 113
 114 static long
 115 binary_get_symtab_upper_bound (bfd *abfd ATTRIBUTE_UNUSED)
 116 {
 117   return (BIN_SYMS + 1) * sizeof (asymbol *);
 118 }
 119
 120 /* Create a symbol name based on the bfd's filename.  */
 121
 122 static char *
 123 mangle_name (bfd *abfd, char *suffix)
 124 {
 125   bfd_size_type size;
 126   char *buf;
 127   char *p;
 128
 129   size = (strlen (bfd_get_filename (abfd))
 130           + strlen (suffix)
 131           + sizeof "_binary__");
 132
 133   buf = (char *) bfd_alloc (abfd, size);
 134   if (buf == NULL)
 135     return "";
 136
 137   sprintf (buf, "_binary_%s_%s", bfd_get_filename (abfd), suffix);
 138
 139   /* Change any non-alphanumeric characters to underscores.  */
 140   for (p = buf; *p; p++)
 141     if (! ISALNUM (*p))
 142       *p = '_';
 143
 144   return buf;
 145 }
 146
 147 /* Return the symbol table.  */
 148
 149 static long
 150 binary_canonicalize_symtab (bfd *abfd, asymbol **alocation)
 151 {
 152   asection *sec = (asection *) abfd->tdata.any;
 153   asymbol *syms;
 154   unsigned int i;
 155   bfd_size_type amt = BIN_SYMS * sizeof (asymbol);
 156
 157   syms = (asymbol *) bfd_alloc (abfd, amt);
 158   if (syms == NULL)
 159     return -1;
 160
 161   /* Start symbol.  */
 162   syms[0].the_bfd = abfd;
 163   syms[0].name = mangle_name (abfd, "start");
 164   syms[0].value = 0;
 165   syms[0].flags = BSF_GLOBAL;
 166   syms[0].section = sec;
 167   syms[0].udata.p = NULL;
 168
 169   /* End symbol.  */
 170   syms[1].the_bfd = abfd;
 171   syms[1].name = mangle_name (abfd, "end");
 172   syms[1].value = sec->size;
 173   syms[1].flags = BSF_GLOBAL;
 174   syms[1].section = sec;
 175   syms[1].udata.p = NULL;
 176
 177   /* Size symbol.  */
 178   syms[2].the_bfd = abfd;
 179   syms[2].name = mangle_name (abfd, "size");
 180   syms[2].value = sec->size;
 181   syms[2].flags = BSF_GLOBAL;
 182   syms[2].section = bfd_abs_section_ptr;
 183   syms[2].udata.p = NULL;
 184
 185   for (i = 0; i < BIN_SYMS; i++)
 186     *alocation++ = syms++;
 187   *alocation = NULL;
 188
 189   return BIN_SYMS;
 190 }
 191
 192 #define binary_make_empty_symbol  _bfd_generic_make_empty_symbol
 193 #define binary_print_symbol       _bfd_nosymbols_print_symbol
 194
 195 /* Get information about a symbol.  */
 196
 197 static void
 198 binary_get_symbol_info (bfd *ignore_abfd ATTRIBUTE_UNUSED,
 199                         asymbol *symbol,
 200                         symbol_info *ret)
 201 {
 202   bfd_symbol_info (symbol, ret);
 203 }
 204
 205 #define binary_bfd_is_local_label_name      bfd_generic_is_local_label_name
 206 #define binary_get_lineno                  _bfd_nosymbols_get_lineno
 207 #define binary_find_nearest_line           _bfd_nosymbols_find_nearest_line
 208 #define binary_find_inliner_info           _bfd_nosymbols_find_inliner_info
 209 #define binary_bfd_make_debug_symbol       _bfd_nosymbols_bfd_make_debug_symbol
 210 #define binary_read_minisymbols            _bfd_generic_read_minisymbols
 211 #define binary_minisymbol_to_symbol        _bfd_generic_minisymbol_to_symbol
 212 #define binary_bfd_is_target_special_symbol ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false)
 213
 214 /* Set the architecture of a binary file.  */
 215 #define binary_set_arch_mach _bfd_generic_set_arch_mach
 216
 217 /* Write section contents of a binary file.  */
 218
 219 static bfd_boolean
 220 binary_set_section_contents (bfd *abfd,
 221                              asection *sec,
 222                              const void * data,
 223                              file_ptr offset,
 224                              bfd_size_type size)
 225 {
 226   if (size == 0)
 227     return TRUE;
 228
 229   if (! abfd->output_has_begun)
 230     {
 231       bfd_boolean found_low;
 232       bfd_vma low;
 233       asection *s;
 234
 235       /* The lowest section LMA sets the virtual address of the start
 236          of the file.  We use this to set the file position of all the
 237          sections.  */
 238       found_low = FALSE;
 239       low = 0;
 240       for (s = abfd->sections; s != NULL; s = s->next)
 241         if (((s->flags
 242               & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD))
 243              == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC))
 244             && (s->size > 0)
 245             && (! found_low || s->lma < low))
 246           {
 247             low = s->lma;
 248             found_low = TRUE;
 249           }
 250
 251       for (s = abfd->sections; s != NULL; s = s->next)
 252         {
 253           s->filepos = s->lma - low;
 254
 255           /* Skip following warning check for sections that will not
 256              occupy file space.  */
 257           if ((s->flags
 258                & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD))
 259               != (SEC_HAS_CONTENTS | SEC_ALLOC)
 260               || (s->size == 0))
 261             continue;
 262
 263           /* If attempting to generate a binary file from a bfd with
 264              LMA's all over the place, huge (sparse?) binary files may
 265              result.  This condition attempts to detect this situation
 266              and print a warning.  Better heuristics would be nice to
 267              have.  */
 268
 269           if (s->filepos < 0)
 270             (*_bfd_error_handler)
 271               (_("Warning: Writing section `%s' to huge (ie negative) file offset 0x%lx."),
 272                bfd_get_section_name (abfd, s),
 273                (unsigned long) s->filepos);
 274         }
 275
 276       abfd->output_has_begun = TRUE;
 277     }
 278
 279   /* We don't want to output anything for a section that is neither
 280      loaded nor allocated.  The contents of such a section are not
 281      meaningful in the binary format.  */
 282   if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0)
 283     return TRUE;
 284   if ((sec->flags & SEC_NEVER_LOAD) != 0)
 285     return TRUE;
 286
 287   return _bfd_generic_set_section_contents (abfd, sec, data, offset, size);
 288 }
 289
 290 /* No space is required for header information.  */
 291
 292 static int
 293 binary_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED,
 294                        struct bfd_link_info *info ATTRIBUTE_UNUSED)
 295 {
 296   return 0;
 297 }
 298
 299 #define binary_bfd_get_relocated_section_contents  bfd_generic_get_relocated_section_contents
 300 #define binary_bfd_relax_section                   bfd_generic_relax_section
 301 #define binary_bfd_gc_sections                     bfd_generic_gc_sections
 302 #define binary_bfd_merge_sections                  bfd_generic_merge_sections
 303 #define binary_bfd_is_group_section                bfd_generic_is_group_section
 304 #define binary_bfd_discard_group                   bfd_generic_discard_group
 305 #define binary_section_already_linked             _bfd_generic_section_already_linked
 306 #define binary_bfd_define_common_symbol            bfd_generic_define_common_symbol
 307 #define binary_bfd_link_hash_table_create         _bfd_generic_link_hash_table_create
 308 #define binary_bfd_link_hash_table_free           _bfd_generic_link_hash_table_free
 309 #define binary_bfd_link_just_syms                 _bfd_generic_link_just_syms
 310 #define binary_bfd_copy_link_hash_symbol_type \
 311   _bfd_generic_copy_link_hash_symbol_type
 312 #define binary_bfd_link_add_symbols               _bfd_generic_link_add_symbols
 313 #define binary_bfd_final_link                     _bfd_generic_final_link
 314 #define binary_bfd_link_split_section             _bfd_generic_link_split_section
 315 #define binary_get_section_contents_in_window     _bfd_generic_get_section_contents_in_window
 316
 317 const bfd_target binary_vec =
 318 {
 319   "binary",                     /* name */
 320   bfd_target_unknown_flavour,   /* flavour */
 321   BFD_ENDIAN_UNKNOWN,           /* byteorder */
 322   BFD_ENDIAN_UNKNOWN,           /* header_byteorder */
 323   EXEC_P,                       /* object_flags */
 324   (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE | SEC_DATA
 325    | SEC_ROM | SEC_HAS_CONTENTS), /* section_flags */
 326   0,                            /* symbol_leading_char */
 327   ' ',                          /* ar_pad_char */
 328   16,                           /* ar_max_namelen */
 329   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 330   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 331   bfd_getb16, bfd_getb_signed_16, bfd_putb16,   /* data */
 332   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 333   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 334   bfd_getb16, bfd_getb_signed_16, bfd_putb16,   /* hdrs */
 335   {                             /* bfd_check_format */
 336     _bfd_dummy_target,
 337     binary_object_p,
 338     _bfd_dummy_target,
 339     _bfd_dummy_target,
 340   },
 341   {                             /* bfd_set_format */
 342     bfd_false,
 343     binary_mkobject,
 344     bfd_false,
 345     bfd_false,
 346   },
 347   {                             /* bfd_write_contents */
 348     bfd_false,
 349     bfd_true,
 350     bfd_false,
 351     bfd_false,
 352   },
 353
 354   BFD_JUMP_TABLE_GENERIC (binary),
 355   BFD_JUMP_TABLE_COPY (_bfd_generic),
 356   BFD_JUMP_TABLE_CORE (_bfd_nocore),
 357   BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 358   BFD_JUMP_TABLE_SYMBOLS (binary),
 359   BFD_JUMP_TABLE_RELOCS (_bfd_norelocs),
 360   BFD_JUMP_TABLE_WRITE (binary),
 361   BFD_JUMP_TABLE_LINK (binary),
 362   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 363
 364   NULL,
 365
 366   NULL
 367 };