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