bfd/binary.c

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