bfd/binary.c

   1 /* BFD back-end for binary objects.
   2    Copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
   3    2004 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 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 /* This is a BFD backend which may be used to write binary objects.
  23    It may only be used for output, not input.  The intention is that
  24    this may be used as an output format for objcopy in order to
  25    generate raw binary data.
  26
  27    This is very simple.  The only complication is that the real data
  28    will start at some address X, and in some cases we will not want to
  29    include X zeroes just to get to that point.  Since the start
  30    address is not meaningful for this object file format, we use it
  31    instead to indicate the number of zeroes to skip at the start of
  32    the file.  objcopy cooperates by specially setting the start
  33    address to zero by default.  */
  34
  35 #include "bfd.h"
  36 #include "sysdep.h"
  37 #include "safe-ctype.h"
  38 #include "libbfd.h"
  39
  40 /* Any bfd we create by reading a binary file has three symbols:
  41    a start symbol, an end symbol, and an absolute length symbol.  */
  42 #define BIN_SYMS 3
  43
  44 static bfd_boolean binary_mkobject PARAMS ((bfd *));
  45 static const bfd_target *binary_object_p PARAMS ((bfd *));
  46 static bfd_boolean binary_get_section_contents
  47   PARAMS ((bfd *, asection *, PTR, file_ptr, bfd_size_type));
  48 static long binary_get_symtab_upper_bound PARAMS ((bfd *));
  49 static char *mangle_name PARAMS ((bfd *, char *));
  50 static long binary_canonicalize_symtab PARAMS ((bfd *, asymbol **));
  51 static void binary_get_symbol_info PARAMS ((bfd *, asymbol *, symbol_info *));
  52 static bfd_boolean binary_set_section_contents
  53   PARAMS ((bfd *, asection *, const PTR, file_ptr, bfd_size_type));
  54 static int binary_sizeof_headers PARAMS ((bfd *, bfd_boolean));
  55
  56 /* Set by external programs - specifies the BFD architecture and
  57    machine number to be uses when creating binary BFDs.  */
  58 enum bfd_architecture  bfd_external_binary_architecture = bfd_arch_unknown;
  59 unsigned long          bfd_external_machine = 0;
  60
  61 /* Create a binary object.  Invoked via bfd_set_format.  */
  62
  63 static bfd_boolean
  64 binary_mkobject (abfd)
  65      bfd *abfd ATTRIBUTE_UNUSED;
  66 {
  67   return TRUE;
  68 }
  69
  70 /* Any file may be considered to be a binary file, provided the target
  71    was not defaulted.  That is, it must be explicitly specified as
  72    being binary.  */
  73
  74 static const bfd_target *
  75 binary_object_p (abfd)
  76      bfd *abfd;
  77 {
  78   struct stat statbuf;
  79   asection *sec;
  80
  81   if (abfd->target_defaulted)
  82     {
  83       bfd_set_error (bfd_error_wrong_format);
  84       return NULL;
  85     }
  86
  87   abfd->symcount = BIN_SYMS;
  88
  89   /* Find the file size.  */
  90   if (bfd_stat (abfd, &statbuf) < 0)
  91     {
  92       bfd_set_error (bfd_error_system_call);
  93       return NULL;
  94     }
  95
  96   /* One data section.  */
  97   sec = bfd_make_section (abfd, ".data");
  98   if (sec == NULL)
  99     return NULL;
 100   sec->flags = SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS;
 101   sec->vma = 0;
 102   sec->size = statbuf.st_size;
 103   sec->filepos = 0;
 104
 105   abfd->tdata.any = (PTR) sec;
 106
 107   if (bfd_get_arch_info (abfd) != NULL)
 108     {
 109       if ((bfd_get_arch_info (abfd)->arch == bfd_arch_unknown)
 110           && (bfd_external_binary_architecture != bfd_arch_unknown))
 111         bfd_set_arch_info (abfd, bfd_lookup_arch
 112                            (bfd_external_binary_architecture, bfd_external_machine));
 113     }
 114
 115   return abfd->xvec;
 116 }
 117
 118 #define binary_close_and_cleanup _bfd_generic_close_and_cleanup
 119 #define binary_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
 120 #define binary_new_section_hook _bfd_generic_new_section_hook
 121
 122 /* Get contents of the only section.  */
 123
 124 static bfd_boolean
 125 binary_get_section_contents (abfd, section, location, offset, count)
 126      bfd *abfd;
 127      asection *section ATTRIBUTE_UNUSED;
 128      PTR location;
 129      file_ptr offset;
 130      bfd_size_type count;
 131 {
 132   if (bfd_seek (abfd, offset, SEEK_SET) != 0
 133       || bfd_bread (location, count, abfd) != count)
 134     return FALSE;
 135   return TRUE;
 136 }
 137
 138 /* Return the amount of memory needed to read the symbol table.  */
 139
 140 static long
 141 binary_get_symtab_upper_bound (abfd)
 142      bfd *abfd ATTRIBUTE_UNUSED;
 143 {
 144   return (BIN_SYMS + 1) * sizeof (asymbol *);
 145 }
 146
 147 /* Create a symbol name based on the bfd's filename.  */
 148
 149 static char *
 150 mangle_name (abfd, suffix)
 151      bfd *abfd;
 152      char *suffix;
 153 {
 154   bfd_size_type size;
 155   char *buf;
 156   char *p;
 157
 158   size = (strlen (bfd_get_filename (abfd))
 159           + strlen (suffix)
 160           + sizeof "_binary__");
 161
 162   buf = (char *) bfd_alloc (abfd, size);
 163   if (buf == NULL)
 164     return "";
 165
 166   sprintf (buf, "_binary_%s_%s", bfd_get_filename (abfd), suffix);
 167
 168   /* Change any non-alphanumeric characters to underscores.  */
 169   for (p = buf; *p; p++)
 170     if (! ISALNUM (*p))
 171       *p = '_';
 172
 173   return buf;
 174 }
 175
 176 /* Return the symbol table.  */
 177
 178 static long
 179 binary_canonicalize_symtab (abfd, alocation)
 180      bfd *abfd;
 181      asymbol **alocation;
 182 {
 183   asection *sec = (asection *) abfd->tdata.any;
 184   asymbol *syms;
 185   unsigned int i;
 186   bfd_size_type amt = BIN_SYMS * sizeof (asymbol);
 187
 188   syms = (asymbol *) bfd_alloc (abfd, amt);
 189   if (syms == NULL)
 190     return 0;
 191
 192   /* Start symbol.  */
 193   syms[0].the_bfd = abfd;
 194   syms[0].name = mangle_name (abfd, "start");
 195   syms[0].value = 0;
 196   syms[0].flags = BSF_GLOBAL;
 197   syms[0].section = sec;
 198   syms[0].udata.p = NULL;
 199
 200   /* End symbol.  */
 201   syms[1].the_bfd = abfd;
 202   syms[1].name = mangle_name (abfd, "end");
 203   syms[1].value = sec->size;
 204   syms[1].flags = BSF_GLOBAL;
 205   syms[1].section = sec;
 206   syms[1].udata.p = NULL;
 207
 208   /* Size symbol.  */
 209   syms[2].the_bfd = abfd;
 210   syms[2].name = mangle_name (abfd, "size");
 211   syms[2].value = sec->size;
 212   syms[2].flags = BSF_GLOBAL;
 213   syms[2].section = bfd_abs_section_ptr;
 214   syms[2].udata.p = NULL;
 215
 216   for (i = 0; i < BIN_SYMS; i++)
 217     *alocation++ = syms++;
 218   *alocation = NULL;
 219
 220   return BIN_SYMS;
 221 }
 222
 223 #define binary_make_empty_symbol _bfd_generic_make_empty_symbol
 224 #define binary_print_symbol _bfd_nosymbols_print_symbol
 225
 226 /* Get information about a symbol.  */
 227
 228 static void
 229 binary_get_symbol_info (ignore_abfd, symbol, ret)
 230      bfd *ignore_abfd ATTRIBUTE_UNUSED;
 231      asymbol *symbol;
 232      symbol_info *ret;
 233 {
 234   bfd_symbol_info (symbol, ret);
 235 }
 236
 237 #define binary_bfd_is_local_label_name bfd_generic_is_local_label_name
 238 #define binary_get_lineno _bfd_nosymbols_get_lineno
 239 #define binary_find_nearest_line _bfd_nosymbols_find_nearest_line
 240 #define binary_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 241 #define binary_read_minisymbols _bfd_generic_read_minisymbols
 242 #define binary_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol
 243
 244 #define binary_get_reloc_upper_bound \
 245   ((long (*) PARAMS ((bfd *, asection *))) bfd_0l)
 246 #define binary_canonicalize_reloc \
 247   ((long (*) PARAMS ((bfd *, asection *, arelent **, asymbol **))) bfd_0l)
 248 #define binary_bfd_reloc_type_lookup _bfd_norelocs_bfd_reloc_type_lookup
 249
 250 /* Set the architecture of a binary file.  */
 251 #define binary_set_arch_mach _bfd_generic_set_arch_mach
 252
 253 /* Write section contents of a binary file.  */
 254
 255 static bfd_boolean
 256 binary_set_section_contents (abfd, sec, data, offset, size)
 257      bfd *abfd;
 258      asection *sec;
 259      const PTR data;
 260      file_ptr offset;
 261      bfd_size_type size;
 262 {
 263   if (size == 0)
 264     return TRUE;
 265
 266   if (! abfd->output_has_begun)
 267     {
 268       bfd_boolean found_low;
 269       bfd_vma low;
 270       asection *s;
 271
 272       /* The lowest section LMA sets the virtual address of the start
 273          of the file.  We use this to set the file position of all the
 274          sections.  */
 275       found_low = FALSE;
 276       low = 0;
 277       for (s = abfd->sections; s != NULL; s = s->next)
 278         if (((s->flags
 279               & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD))
 280              == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC))
 281             && (s->size > 0)
 282             && (! found_low || s->lma < low))
 283           {
 284             low = s->lma;
 285             found_low = TRUE;
 286           }
 287
 288       for (s = abfd->sections; s != NULL; s = s->next)
 289         {
 290           s->filepos = s->lma - low;
 291
 292           /* Skip following warning check for sections that will not
 293              occupy file space.  */
 294           if ((s->flags
 295                & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD))
 296               != (SEC_HAS_CONTENTS | SEC_ALLOC)
 297               || (s->size == 0))
 298             continue;
 299
 300           /* If attempting to generate a binary file from a bfd with
 301              LMA's all over the place, huge (sparse?) binary files may
 302              result.  This condition attempts to detect this situation
 303              and print a warning.  Better heuristics would be nice to
 304              have.  */
 305
 306           if (s->filepos < 0)
 307             (*_bfd_error_handler)
 308               (_("Warning: Writing section `%s' to huge (ie negative) file offset 0x%lx."),
 309                bfd_get_section_name (abfd, s),
 310                (unsigned long) s->filepos);
 311         }
 312
 313       abfd->output_has_begun = TRUE;
 314     }
 315
 316   /* We don't want to output anything for a section that is neither
 317      loaded nor allocated.  The contents of such a section are not
 318      meaningful in the binary format.  */
 319   if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0)
 320     return TRUE;
 321   if ((sec->flags & SEC_NEVER_LOAD) != 0)
 322     return TRUE;
 323
 324   return _bfd_generic_set_section_contents (abfd, sec, data, offset, size);
 325 }
 326
 327 /* No space is required for header information.  */
 328
 329 static int
 330 binary_sizeof_headers (abfd, exec)
 331      bfd *abfd ATTRIBUTE_UNUSED;
 332      bfd_boolean exec ATTRIBUTE_UNUSED;
 333 {
 334   return 0;
 335 }
 336
 337 #define binary_bfd_get_relocated_section_contents \
 338   bfd_generic_get_relocated_section_contents
 339 #define binary_bfd_relax_section bfd_generic_relax_section
 340 #define binary_bfd_gc_sections bfd_generic_gc_sections
 341 #define binary_bfd_merge_sections bfd_generic_merge_sections
 342 #define binary_bfd_is_group_section bfd_generic_is_group_section
 343 #define binary_bfd_discard_group bfd_generic_discard_group
 344 #define binary_section_already_linked \
 345   _bfd_generic_section_already_linked
 346 #define binary_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 347 #define binary_bfd_link_hash_table_free _bfd_generic_link_hash_table_free
 348 #define binary_bfd_link_just_syms _bfd_generic_link_just_syms
 349 #define binary_bfd_link_add_symbols _bfd_generic_link_add_symbols
 350 #define binary_bfd_final_link _bfd_generic_final_link
 351 #define binary_bfd_link_split_section _bfd_generic_link_split_section
 352 #define binary_get_section_contents_in_window \
 353   _bfd_generic_get_section_contents_in_window
 354
 355 const bfd_target binary_vec =
 356 {
 357   "binary",                     /* name */
 358   bfd_target_unknown_flavour,   /* flavour */
 359   BFD_ENDIAN_UNKNOWN,           /* byteorder */
 360   BFD_ENDIAN_UNKNOWN,           /* header_byteorder */
 361   EXEC_P,                       /* object_flags */
 362   (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE | SEC_DATA
 363    | SEC_ROM | SEC_HAS_CONTENTS), /* section_flags */
 364   0,                            /* symbol_leading_char */
 365   ' ',                          /* ar_pad_char */
 366   16,                           /* ar_max_namelen */
 367   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 368   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 369   bfd_getb16, bfd_getb_signed_16, bfd_putb16,   /* data */
 370   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 371   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 372   bfd_getb16, bfd_getb_signed_16, bfd_putb16,   /* hdrs */
 373   {                             /* bfd_check_format */
 374     _bfd_dummy_target,
 375     binary_object_p,            /* bfd_check_format */
 376     _bfd_dummy_target,
 377     _bfd_dummy_target,
 378   },
 379   {                             /* bfd_set_format */
 380     bfd_false,
 381     binary_mkobject,
 382     bfd_false,
 383     bfd_false,
 384   },
 385   {                             /* bfd_write_contents */
 386     bfd_false,
 387     bfd_true,
 388     bfd_false,
 389     bfd_false,
 390   },
 391
 392   BFD_JUMP_TABLE_GENERIC (binary),
 393   BFD_JUMP_TABLE_COPY (_bfd_generic),
 394   BFD_JUMP_TABLE_CORE (_bfd_nocore),
 395   BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 396   BFD_JUMP_TABLE_SYMBOLS (binary),
 397   BFD_JUMP_TABLE_RELOCS (binary),
 398   BFD_JUMP_TABLE_WRITE (binary),
 399   BFD_JUMP_TABLE_LINK (binary),
 400   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 401
 402   NULL,
 403
 404   NULL
 405 };