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 /* Set by external programs - specifies the BFD architecture
  59    to use when creating binary BFDs.  */
  60 enum bfd_architecture bfd_external_binary_architecture = bfd_arch_unknown;
  61
  62 /* Create a binary object.  Invoked via bfd_set_format.  */
  63
  64 static boolean
  65 binary_mkobject (abfd)
  66      bfd *abfd ATTRIBUTE_UNUSED;
  67 {
  68   return true;
  69 }
  70
  71 /* Any file may be considered to be a binary file, provided the target
  72    was not defaulted.  That is, it must be explicitly specified as
  73    being binary.  */
  74
  75 static const bfd_target *
  76 binary_object_p (abfd)
  77      bfd *abfd;
  78 {
  79   struct stat statbuf;
  80   asection *sec;
  81
  82   if (abfd->target_defaulted)
  83     {
  84       bfd_set_error (bfd_error_wrong_format);
  85       return NULL;
  86     }
  87
  88   abfd->symcount = BIN_SYMS;
  89
  90   /* Find the file size.  */
  91   if (bfd_stat (abfd, &statbuf) < 0)
  92     {
  93       bfd_set_error (bfd_error_system_call);
  94       return NULL;
  95     }
  96
  97   /* One data section.  */
  98   sec = bfd_make_section (abfd, ".data");
  99   if (sec == NULL)
 100     return NULL;
 101   sec->flags = SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS;
 102   sec->vma = 0;
 103   sec->_raw_size = statbuf.st_size;
 104   sec->filepos = 0;
 105
 106   abfd->tdata.any = (PTR) sec;
 107
 108   if (bfd_get_arch_info (abfd) != NULL)
 109     {
 110       if ((bfd_get_arch_info (abfd)->arch == bfd_arch_unknown)
 111           && (bfd_external_binary_architecture != bfd_arch_unknown))
 112         bfd_set_arch_info (abfd, bfd_lookup_arch (bfd_external_binary_architecture, 0));
 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 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_read (location, 1, 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   int 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 ((unsigned char) *p))
 171       *p = '_';
 172
 173   return buf;
 174 }
 175
 176 /* Return the symbol table.  */
 177
 178 static long
 179 binary_get_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
 187   syms = (asymbol *) bfd_alloc (abfd, BIN_SYMS * sizeof (asymbol));
 188   if (syms == NULL)
 189     return false;
 190
 191   /* Start symbol.  */
 192   syms[0].the_bfd = abfd;
 193   syms[0].name = mangle_name (abfd, "start");
 194   syms[0].value = 0;
 195   syms[0].flags = BSF_GLOBAL;
 196   syms[0].section = sec;
 197   syms[0].udata.p = NULL;
 198
 199   /* End symbol.  */
 200   syms[1].the_bfd = abfd;
 201   syms[1].name = mangle_name (abfd, "end");
 202   syms[1].value = sec->_raw_size;
 203   syms[1].flags = BSF_GLOBAL;
 204   syms[1].section = sec;
 205   syms[1].udata.p = NULL;
 206
 207   /* Size symbol.  */
 208   syms[2].the_bfd = abfd;
 209   syms[2].name = mangle_name (abfd, "size");
 210   syms[2].value = sec->_raw_size;
 211   syms[2].flags = BSF_GLOBAL;
 212   syms[2].section = bfd_abs_section_ptr;
 213   syms[2].udata.p = NULL;
 214
 215   for (i = 0; i < BIN_SYMS; i++)
 216     *alocation++ = syms++;
 217   *alocation = NULL;
 218
 219   return BIN_SYMS;
 220 }
 221
 222 /* Make an empty symbol.  */
 223
 224 static asymbol *
 225 binary_make_empty_symbol (abfd)
 226      bfd *abfd;
 227 {
 228   return (asymbol *) bfd_alloc (abfd, sizeof (asymbol));
 229 }
 230
 231 #define binary_print_symbol _bfd_nosymbols_print_symbol
 232
 233 /* Get information about a symbol.  */
 234
 235 static void
 236 binary_get_symbol_info (ignore_abfd, symbol, ret)
 237      bfd *ignore_abfd ATTRIBUTE_UNUSED;
 238      asymbol *symbol;
 239      symbol_info *ret;
 240 {
 241   bfd_symbol_info (symbol, ret);
 242 }
 243
 244 #define binary_bfd_is_local_label_name bfd_generic_is_local_label_name
 245 #define binary_get_lineno _bfd_nosymbols_get_lineno
 246 #define binary_find_nearest_line _bfd_nosymbols_find_nearest_line
 247 #define binary_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 248 #define binary_read_minisymbols _bfd_generic_read_minisymbols
 249 #define binary_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol
 250
 251 #define binary_get_reloc_upper_bound \
 252   ((long (*) PARAMS ((bfd *, asection *))) bfd_0l)
 253 #define binary_canonicalize_reloc \
 254   ((long (*) PARAMS ((bfd *, asection *, arelent **, asymbol **))) bfd_0l)
 255 #define binary_bfd_reloc_type_lookup _bfd_norelocs_bfd_reloc_type_lookup
 256
 257 /* Set the architecture of a binary file.  */
 258 #define binary_set_arch_mach _bfd_generic_set_arch_mach
 259
 260 /* Write section contents of a binary file.  */
 261
 262 static boolean
 263 binary_set_section_contents (abfd, sec, data, offset, size)
 264      bfd *abfd;
 265      asection *sec;
 266      PTR data;
 267      file_ptr offset;
 268      bfd_size_type size;
 269 {
 270   if (size == 0)
 271     return true;
 272
 273   if (! abfd->output_has_begun)
 274     {
 275       boolean found_low;
 276       bfd_vma low;
 277       asection *s;
 278
 279       /* The lowest section LMA sets the virtual address of the start
 280          of the file.  We use this to set the file position of all the
 281          sections.  */
 282       found_low = false;
 283       low = 0;
 284       for (s = abfd->sections; s != NULL; s = s->next)
 285         if (((s->flags
 286               & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD))
 287              == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC))
 288             && (s->_raw_size > 0)
 289             && (! found_low || s->lma < low))
 290           {
 291             low = s->lma;
 292             found_low = true;
 293           }
 294
 295       for (s = abfd->sections; s != NULL; s = s->next)
 296         {
 297           s->filepos = s->lma - low;
 298
 299           /* Skip following warning check for sections that will not
 300              occupy file space.  */
 301           if ((s->flags
 302                & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD))
 303               != (SEC_HAS_CONTENTS | SEC_ALLOC)
 304               || (s->_raw_size == 0))
 305             continue;
 306
 307           /* If attempting to generate a binary file from a bfd with
 308              LMA's all over the place, huge (sparse?) binary files may
 309              result.  This condition attempts to detect this situation
 310              and print a warning.  Better heuristics would be nice to
 311              have.  */
 312
 313           if (s->filepos < 0)
 314             (*_bfd_error_handler)
 315               (_("Warning: Writing section `%s' to huge (ie negative) file offset 0x%lx."),
 316                bfd_get_section_name (abfd, s),
 317                (unsigned long) s->filepos);
 318         }
 319
 320       abfd->output_has_begun = true;
 321     }
 322
 323   /* We don't want to output anything for a section that is neither
 324      loaded nor allocated.  The contents of such a section are not
 325      meaningful in the binary format.  */
 326   if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0)
 327     return true;
 328   if ((sec->flags & SEC_NEVER_LOAD) != 0)
 329     return true;
 330
 331   return _bfd_generic_set_section_contents (abfd, sec, data, offset, size);
 332 }
 333
 334 /* No space is required for header information.  */
 335
 336 static int
 337 binary_sizeof_headers (abfd, exec)
 338      bfd *abfd ATTRIBUTE_UNUSED;
 339      boolean exec ATTRIBUTE_UNUSED;
 340 {
 341   return 0;
 342 }
 343
 344 #define binary_bfd_get_relocated_section_contents \
 345   bfd_generic_get_relocated_section_contents
 346 #define binary_bfd_relax_section bfd_generic_relax_section
 347 #define binary_bfd_gc_sections bfd_generic_gc_sections
 348 #define binary_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 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 };