bfd/binary.c

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