bfd/binary.c

   1 /* BFD back-end for binary objects.
   2    Copyright 1994, 95, 96, 97, 98, 1999 Free Software Foundation, Inc.
   3    Written by Ian Lance Taylor, Cygnus Support, <ian@cygnus.com>
   4
   5 This file is part of BFD, the Binary File Descriptor library.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; if not, write to the Free Software
  19 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 /* This is a BFD backend which may be used to write binary objects.
  22    It may only be used for output, not input.  The intention is that
  23    this may be used as an output format for objcopy in order to
  24    generate raw binary data.
  25
  26    This is very simple.  The only complication is that the real data
  27    will start at some address X, and in some cases we will not want to
  28    include X zeroes just to get to that point.  Since the start
  29    address is not meaningful for this object file format, we use it
  30    instead to indicate the number of zeroes to skip at the start of
  31    the file.  objcopy cooperates by specially setting the start
  32    address to zero by default.  */
  33
  34 #include <ctype.h>
  35
  36 #include "bfd.h"
  37 #include "sysdep.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 asymbol *binary_make_empty_symbol PARAMS ((bfd *));
  52 static void binary_get_symbol_info PARAMS ((bfd *, asymbol *, symbol_info *));
  53 static boolean binary_set_section_contents
  54   PARAMS ((bfd *, asection *, PTR, file_ptr, bfd_size_type));
  55 static int binary_sizeof_headers PARAMS ((bfd *, boolean));
  56
  57 /* Create a binary object.  Invoked via bfd_set_format.  */
  58
  59 static boolean
  60 binary_mkobject (abfd)
  61      bfd *abfd ATTRIBUTE_UNUSED;
  62 {
  63   return true;
  64 }
  65
  66 /* Any file may be considered to be a binary file, provided the target
  67    was not defaulted.  That is, it must be explicitly specified as
  68    being binary.  */
  69
  70 static const bfd_target *
  71 binary_object_p (abfd)
  72      bfd *abfd;
  73 {
  74   struct stat statbuf;
  75   asection *sec;
  76
  77   if (abfd->target_defaulted)
  78     {
  79       bfd_set_error (bfd_error_wrong_format);
  80       return NULL;
  81     }
  82
  83   abfd->symcount = BIN_SYMS;
  84
  85   /* Find the file size.  */
  86   if (bfd_stat (abfd, &statbuf) < 0)
  87     {
  88       bfd_set_error (bfd_error_system_call);
  89       return NULL;
  90     }
  91
  92   /* One data section.  */
  93   sec = bfd_make_section (abfd, ".data");
  94   if (sec == NULL)
  95     return NULL;
  96   sec->flags = SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS;
  97   sec->vma = 0;
  98   sec->_raw_size = statbuf.st_size;
  99   sec->filepos = 0;
 100
 101   abfd->tdata.any = (PTR) sec;
 102
 103   return abfd->xvec;
 104 }
 105
 106 #define binary_close_and_cleanup _bfd_generic_close_and_cleanup
 107 #define binary_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
 108 #define binary_new_section_hook _bfd_generic_new_section_hook
 109
 110 /* Get contents of the only section.  */
 111
 112 static boolean
 113 binary_get_section_contents (abfd, section, location, offset, count)
 114      bfd *abfd;
 115      asection *section ATTRIBUTE_UNUSED;
 116      PTR location;
 117      file_ptr offset;
 118      bfd_size_type count;
 119 {
 120   if (bfd_seek (abfd, offset, SEEK_SET) != 0
 121       || bfd_read (location, 1, count, abfd) != count)
 122     return false;
 123   return true;
 124 }
 125
 126 /* Return the amount of memory needed to read the symbol table.  */
 127
 128 static long
 129 binary_get_symtab_upper_bound (abfd)
 130      bfd *abfd ATTRIBUTE_UNUSED;
 131 {
 132   return (BIN_SYMS + 1) * sizeof (asymbol *);
 133 }
 134
 135 /* Create a symbol name based on the bfd's filename.  */
 136
 137 static char *
 138 mangle_name (abfd, suffix)
 139      bfd *abfd;
 140      char *suffix;
 141 {
 142   int size;
 143   char *buf;
 144   char *p;
 145
 146   size = (strlen (bfd_get_filename (abfd))
 147           + strlen (suffix)
 148           + sizeof "_binary__");
 149
 150   buf = (char *) bfd_alloc (abfd, size);
 151   if (buf == NULL)
 152     return "";
 153
 154   sprintf (buf, "_binary_%s_%s", bfd_get_filename (abfd), suffix);
 155
 156   /* Change any non-alphanumeric characters to underscores.  */
 157   for (p = buf; *p; p++)
 158     if (! isalnum ((unsigned char) *p))
 159       *p = '_';
 160
 161   return buf;
 162 }
 163
 164 /* Return the symbol table.  */
 165
 166 static long
 167 binary_get_symtab (abfd, alocation)
 168      bfd *abfd;
 169      asymbol **alocation;
 170 {
 171   asection *sec = (asection *) abfd->tdata.any;
 172   asymbol *syms;
 173   unsigned int i;
 174
 175   syms = (asymbol *) bfd_alloc (abfd, BIN_SYMS * sizeof (asymbol));
 176   if (syms == NULL)
 177     return false;
 178
 179   /* Start symbol.  */
 180   syms[0].the_bfd = abfd;
 181   syms[0].name = mangle_name (abfd, "start");
 182   syms[0].value = 0;
 183   syms[0].flags = BSF_GLOBAL;
 184   syms[0].section = sec;
 185   syms[0].udata.p = NULL;
 186
 187   /* End symbol.  */
 188   syms[1].the_bfd = abfd;
 189   syms[1].name = mangle_name (abfd, "end");
 190   syms[1].value = sec->_raw_size;
 191   syms[1].flags = BSF_GLOBAL;
 192   syms[1].section = sec;
 193   syms[1].udata.p = NULL;
 194
 195   /* Size symbol.  */
 196   syms[2].the_bfd = abfd;
 197   syms[2].name = mangle_name (abfd, "size");
 198   syms[2].value = sec->_raw_size;
 199   syms[2].flags = BSF_GLOBAL;
 200   syms[2].section = bfd_abs_section_ptr;
 201   syms[2].udata.p = NULL;
 202
 203   for (i = 0; i < BIN_SYMS; i++)
 204     *alocation++ = syms++;
 205   *alocation = NULL;
 206
 207   return BIN_SYMS;
 208 }
 209
 210 /* Make an empty symbol.  */
 211
 212 static asymbol *
 213 binary_make_empty_symbol (abfd)
 214      bfd *abfd;
 215 {
 216   return (asymbol *) bfd_alloc (abfd, sizeof (asymbol));
 217 }
 218
 219 #define binary_print_symbol _bfd_nosymbols_print_symbol
 220
 221 /* Get information about a symbol.  */
 222
 223 static void
 224 binary_get_symbol_info (ignore_abfd, symbol, ret)
 225      bfd *ignore_abfd ATTRIBUTE_UNUSED;
 226      asymbol *symbol;
 227      symbol_info *ret;
 228 {
 229   bfd_symbol_info (symbol, ret);
 230 }
 231
 232 #define binary_bfd_is_local_label_name bfd_generic_is_local_label_name
 233 #define binary_get_lineno _bfd_nosymbols_get_lineno
 234 #define binary_find_nearest_line _bfd_nosymbols_find_nearest_line
 235 #define binary_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 236 #define binary_read_minisymbols _bfd_generic_read_minisymbols
 237 #define binary_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol
 238
 239 #define binary_get_reloc_upper_bound \
 240   ((long (*) PARAMS ((bfd *, asection *))) bfd_0l)
 241 #define binary_canonicalize_reloc \
 242   ((long (*) PARAMS ((bfd *, asection *, arelent **, asymbol **))) bfd_0l)
 243 #define binary_bfd_reloc_type_lookup _bfd_norelocs_bfd_reloc_type_lookup
 244
 245 /* Set the architecture of a binary file.  */
 246 #define binary_set_arch_mach _bfd_generic_set_arch_mach
 247
 248 /* Write section contents of a binary file.  */
 249
 250 static boolean
 251 binary_set_section_contents (abfd, sec, data, offset, size)
 252      bfd *abfd;
 253      asection *sec;
 254      PTR data;
 255      file_ptr offset;
 256      bfd_size_type size;
 257 {
 258   if (size == 0)
 259     return true;
 260
 261   if (! abfd->output_has_begun)
 262     {
 263       boolean found_low;
 264       bfd_vma low;
 265       asection *s;
 266
 267       /* The lowest section LMA sets the virtual address of the start
 268          of the file.  We use this to set the file position of all the
 269          sections.  */
 270       found_low = false;
 271       low = 0;
 272       for (s = abfd->sections; s != NULL; s = s->next)
 273         if (((s->flags
 274               & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD))
 275              == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC))
 276             && (s->_raw_size > 0)
 277             && (! found_low || s->lma < low))
 278           {
 279             low = s->lma;
 280             found_low = true;
 281           }
 282
 283       for (s = abfd->sections; s != NULL; s = s->next)
 284         {
 285           s->filepos = s->lma - low;
 286
 287           /* Skip following warning check for sections that will not
 288              occupy file space.  */
 289           if ((s->flags
 290                & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD))
 291               != (SEC_HAS_CONTENTS | SEC_ALLOC)
 292               || (s->_raw_size == 0))
 293             continue;
 294
 295           /* If attempting to generate a binary file from a bfd with
 296              LMA's all over the place, huge (sparse?) binary files may
 297              result.  This condition attempts to detect this situation
 298              and print a warning.  Better heuristics would be nice to
 299              have.  */
 300
 301           if (s->filepos < 0)
 302             (*_bfd_error_handler)
 303               (_("Warning: Writing section `%s' to huge (ie negative) file offset 0x%lx."),
 304                bfd_get_section_name (abfd, s),
 305                (unsigned long) s->filepos);
 306         }
 307
 308       abfd->output_has_begun = true;
 309     }
 310
 311   /* We don't want to output anything for a section that is neither
 312      loaded nor allocated.  The contents of such a section are not
 313      meaningful in the binary format.  */
 314   if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0)
 315     return true;
 316   if ((sec->flags & SEC_NEVER_LOAD) != 0)
 317     return true;
 318
 319   return _bfd_generic_set_section_contents (abfd, sec, data, offset, size);
 320 }
 321
 322 /* No space is required for header information.  */
 323
 324 static int
 325 binary_sizeof_headers (abfd, exec)
 326      bfd *abfd ATTRIBUTE_UNUSED;
 327      boolean exec ATTRIBUTE_UNUSED;
 328 {
 329   return 0;
 330 }
 331
 332 #define binary_bfd_get_relocated_section_contents \
 333   bfd_generic_get_relocated_section_contents
 334 #define binary_bfd_relax_section bfd_generic_relax_section
 335 #define binary_bfd_gc_sections bfd_generic_gc_sections
 336 #define binary_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 337 #define binary_bfd_link_add_symbols _bfd_generic_link_add_symbols
 338 #define binary_bfd_final_link _bfd_generic_final_link
 339 #define binary_bfd_link_split_section _bfd_generic_link_split_section
 340 #define binary_get_section_contents_in_window \
 341   _bfd_generic_get_section_contents_in_window
 342
 343 const bfd_target binary_vec =
 344 {
 345   "binary",                     /* name */
 346   bfd_target_unknown_flavour,   /* flavour */
 347   BFD_ENDIAN_UNKNOWN,           /* byteorder */
 348   BFD_ENDIAN_UNKNOWN,           /* header_byteorder */
 349   EXEC_P,                       /* object_flags */
 350   (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE | SEC_DATA
 351    | SEC_ROM | SEC_HAS_CONTENTS), /* section_flags */
 352   0,                            /* symbol_leading_char */
 353   ' ',                          /* ar_pad_char */
 354   16,                           /* ar_max_namelen */
 355   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 356   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 357   bfd_getb16, bfd_getb_signed_16, bfd_putb16,   /* data */
 358   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 359   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 360   bfd_getb16, bfd_getb_signed_16, bfd_putb16,   /* hdrs */
 361   {                             /* bfd_check_format */
 362     _bfd_dummy_target,
 363     binary_object_p,            /* bfd_check_format */
 364     _bfd_dummy_target,
 365     _bfd_dummy_target,
 366   },
 367   {                             /* bfd_set_format */
 368     bfd_false,
 369     binary_mkobject,
 370     bfd_false,
 371     bfd_false,
 372   },
 373   {                             /* bfd_write_contents */
 374     bfd_false,
 375     bfd_true,
 376     bfd_false,
 377     bfd_false,
 378   },
 379
 380   BFD_JUMP_TABLE_GENERIC (binary),
 381   BFD_JUMP_TABLE_COPY (_bfd_generic),
 382   BFD_JUMP_TABLE_CORE (_bfd_nocore),
 383   BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 384   BFD_JUMP_TABLE_SYMBOLS (binary),
 385   BFD_JUMP_TABLE_RELOCS (binary),
 386   BFD_JUMP_TABLE_WRITE (binary),
 387   BFD_JUMP_TABLE_LINK (binary),
 388   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 389
 390   NULL,
 391
 392   NULL
 393 };