bfd/binary.c

   1 /* BFD back-end for binary objects.
   2    Copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
   3    2003
   4    Free Software Foundation, Inc.
   5    Written by Ian Lance Taylor, Cygnus Support, <ian@cygnus.com>
   6
   7    This file is part of BFD, the Binary File Descriptor library.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  22
  23 /* This is a BFD backend which may be used to write binary objects.
  24    It may only be used for output, not input.  The intention is that
  25    this may be used as an output format for objcopy in order to
  26    generate raw binary data.
  27
  28    This is very simple.  The only complication is that the real data
  29    will start at some address X, and in some cases we will not want to
  30    include X zeroes just to get to that point.  Since the start
  31    address is not meaningful for this object file format, we use it
  32    instead to indicate the number of zeroes to skip at the start of
  33    the file.  objcopy cooperates by specially setting the start
  34    address to zero by default.  */
  35
  36 #include "bfd.h"
  37 #include "sysdep.h"
  38 #include "safe-ctype.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 bfd_boolean binary_mkobject PARAMS ((bfd *));
  46 static const bfd_target *binary_object_p PARAMS ((bfd *));
  47 static bfd_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_canonicalize_symtab PARAMS ((bfd *, asymbol **));
  52 static void binary_get_symbol_info PARAMS ((bfd *, asymbol *, symbol_info *));
  53 static bfd_boolean binary_set_section_contents
  54   PARAMS ((bfd *, asection *, PTR, file_ptr, bfd_size_type));
  55 static int binary_sizeof_headers PARAMS ((bfd *, bfd_boolean));
  56
  57 /* Set by external programs - specifies the BFD architecture and
  58    machine number to be uses when creating binary BFDs.  */
  59 enum bfd_architecture  bfd_external_binary_architecture = bfd_arch_unknown;
  60 unsigned long          bfd_external_machine = 0;
  61
  62 /* Create a binary object.  Invoked via bfd_set_format.  */
  63
  64 static bfd_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
 113                            (bfd_external_binary_architecture, bfd_external_machine));
 114     }
 115
 116   return abfd->xvec;
 117 }
 118
 119 #define binary_close_and_cleanup _bfd_generic_close_and_cleanup
 120 #define binary_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
 121 #define binary_new_section_hook _bfd_generic_new_section_hook
 122
 123 /* Get contents of the only section.  */
 124
 125 static bfd_boolean
 126 binary_get_section_contents (abfd, section, location, offset, count)
 127      bfd *abfd;
 128      asection *section ATTRIBUTE_UNUSED;
 129      PTR location;
 130      file_ptr offset;
 131      bfd_size_type count;
 132 {
 133   if (bfd_seek (abfd, offset, SEEK_SET) != 0
 134       || bfd_bread (location, count, abfd) != count)
 135     return FALSE;
 136   return TRUE;
 137 }
 138
 139 /* Return the amount of memory needed to read the symbol table.  */
 140
 141 static long
 142 binary_get_symtab_upper_bound (abfd)
 143      bfd *abfd ATTRIBUTE_UNUSED;
 144 {
 145   return (BIN_SYMS + 1) * sizeof (asymbol *);
 146 }
 147
 148 /* Create a symbol name based on the bfd's filename.  */
 149
 150 static char *
 151 mangle_name (abfd, suffix)
 152      bfd *abfd;
 153      char *suffix;
 154 {
 155   bfd_size_type size;
 156   char *buf;
 157   char *p;
 158
 159   size = (strlen (bfd_get_filename (abfd))
 160           + strlen (suffix)
 161           + sizeof "_binary__");
 162
 163   buf = (char *) bfd_alloc (abfd, size);
 164   if (buf == NULL)
 165     return "";
 166
 167   sprintf (buf, "_binary_%s_%s", bfd_get_filename (abfd), suffix);
 168
 169   /* Change any non-alphanumeric characters to underscores.  */
 170   for (p = buf; *p; p++)
 171     if (! ISALNUM (*p))
 172       *p = '_';
 173
 174   return buf;
 175 }
 176
 177 /* Return the symbol table.  */
 178
 179 static long
 180 binary_canonicalize_symtab (abfd, alocation)
 181      bfd *abfd;
 182      asymbol **alocation;
 183 {
 184   asection *sec = (asection *) abfd->tdata.any;
 185   asymbol *syms;
 186   unsigned int i;
 187   bfd_size_type amt = BIN_SYMS * sizeof (asymbol);
 188
 189   syms = (asymbol *) bfd_alloc (abfd, amt);
 190   if (syms == NULL)
 191     return 0;
 192
 193   /* Start symbol.  */
 194   syms[0].the_bfd = abfd;
 195   syms[0].name = mangle_name (abfd, "start");
 196   syms[0].value = 0;
 197   syms[0].flags = BSF_GLOBAL;
 198   syms[0].section = sec;
 199   syms[0].udata.p = NULL;
 200
 201   /* End symbol.  */
 202   syms[1].the_bfd = abfd;
 203   syms[1].name = mangle_name (abfd, "end");
 204   syms[1].value = sec->_raw_size;
 205   syms[1].flags = BSF_GLOBAL;
 206   syms[1].section = sec;
 207   syms[1].udata.p = NULL;
 208
 209   /* Size symbol.  */
 210   syms[2].the_bfd = abfd;
 211   syms[2].name = mangle_name (abfd, "size");
 212   syms[2].value = sec->_raw_size;
 213   syms[2].flags = BSF_GLOBAL;
 214   syms[2].section = bfd_abs_section_ptr;
 215   syms[2].udata.p = NULL;
 216
 217   for (i = 0; i < BIN_SYMS; i++)
 218     *alocation++ = syms++;
 219   *alocation = NULL;
 220
 221   return BIN_SYMS;
 222 }
 223
 224 #define binary_make_empty_symbol _bfd_generic_make_empty_symbol
 225 #define binary_print_symbol _bfd_nosymbols_print_symbol
 226
 227 /* Get information about a symbol.  */
 228
 229 static void
 230 binary_get_symbol_info (ignore_abfd, symbol, ret)
 231      bfd *ignore_abfd ATTRIBUTE_UNUSED;
 232      asymbol *symbol;
 233      symbol_info *ret;
 234 {
 235   bfd_symbol_info (symbol, ret);
 236 }
 237
 238 #define binary_bfd_is_local_label_name bfd_generic_is_local_label_name
 239 #define binary_get_lineno _bfd_nosymbols_get_lineno
 240 #define binary_find_nearest_line _bfd_nosymbols_find_nearest_line
 241 #define binary_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 242 #define binary_read_minisymbols _bfd_generic_read_minisymbols
 243 #define binary_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol
 244
 245 #define binary_get_reloc_upper_bound \
 246   ((long (*) PARAMS ((bfd *, asection *))) bfd_0l)
 247 #define binary_canonicalize_reloc \
 248   ((long (*) PARAMS ((bfd *, asection *, arelent **, asymbol **))) bfd_0l)
 249 #define binary_bfd_reloc_type_lookup _bfd_norelocs_bfd_reloc_type_lookup
 250
 251 /* Set the architecture of a binary file.  */
 252 #define binary_set_arch_mach _bfd_generic_set_arch_mach
 253
 254 /* Write section contents of a binary file.  */
 255
 256 static bfd_boolean
 257 binary_set_section_contents (abfd, sec, data, offset, size)
 258      bfd *abfd;
 259      asection *sec;
 260      PTR data;
 261      file_ptr offset;
 262      bfd_size_type size;
 263 {
 264   if (size == 0)
 265     return TRUE;
 266
 267   if (! abfd->output_has_begun)
 268     {
 269       bfd_boolean found_low;
 270       bfd_vma low;
 271       asection *s;
 272
 273       /* The lowest section LMA sets the virtual address of the start
 274          of the file.  We use this to set the file position of all the
 275          sections.  */
 276       found_low = FALSE;
 277       low = 0;
 278       for (s = abfd->sections; s != NULL; s = s->next)
 279         if (((s->flags
 280               & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD))
 281              == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC))
 282             && (s->_raw_size > 0)
 283             && (! found_low || s->lma < low))
 284           {
 285             low = s->lma;
 286             found_low = TRUE;
 287           }
 288
 289       for (s = abfd->sections; s != NULL; s = s->next)
 290         {
 291           s->filepos = s->lma - low;
 292
 293           /* Skip following warning check for sections that will not
 294              occupy file space.  */
 295           if ((s->flags
 296                & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD))
 297               != (SEC_HAS_CONTENTS | SEC_ALLOC)
 298               || (s->_raw_size == 0))
 299             continue;
 300
 301           /* If attempting to generate a binary file from a bfd with
 302              LMA's all over the place, huge (sparse?) binary files may
 303              result.  This condition attempts to detect this situation
 304              and print a warning.  Better heuristics would be nice to
 305              have.  */
 306
 307           if (s->filepos < 0)
 308             (*_bfd_error_handler)
 309               (_("Warning: Writing section `%s' to huge (ie negative) file offset 0x%lx."),
 310                bfd_get_section_name (abfd, s),
 311                (unsigned long) s->filepos);
 312         }
 313
 314       abfd->output_has_begun = TRUE;
 315     }
 316
 317   /* We don't want to output anything for a section that is neither
 318      loaded nor allocated.  The contents of such a section are not
 319      meaningful in the binary format.  */
 320   if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0)
 321     return TRUE;
 322   if ((sec->flags & SEC_NEVER_LOAD) != 0)
 323     return TRUE;
 324
 325   return _bfd_generic_set_section_contents (abfd, sec, data, offset, size);
 326 }
 327
 328 /* No space is required for header information.  */
 329
 330 static int
 331 binary_sizeof_headers (abfd, exec)
 332      bfd *abfd ATTRIBUTE_UNUSED;
 333      bfd_boolean exec ATTRIBUTE_UNUSED;
 334 {
 335   return 0;
 336 }
 337
 338 #define binary_bfd_get_relocated_section_contents \
 339   bfd_generic_get_relocated_section_contents
 340 #define binary_bfd_relax_section bfd_generic_relax_section
 341 #define binary_bfd_gc_sections bfd_generic_gc_sections
 342 #define binary_bfd_merge_sections bfd_generic_merge_sections
 343 #define binary_bfd_discard_group bfd_generic_discard_group
 344 #define binary_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 345 #define binary_bfd_link_hash_table_free _bfd_generic_link_hash_table_free
 346 #define binary_bfd_link_just_syms _bfd_generic_link_just_syms
 347 #define binary_bfd_link_add_symbols _bfd_generic_link_add_symbols
 348 #define binary_bfd_final_link _bfd_generic_final_link
 349 #define binary_bfd_link_split_section _bfd_generic_link_split_section
 350 #define binary_get_section_contents_in_window \
 351   _bfd_generic_get_section_contents_in_window
 352
 353 const bfd_target binary_vec =
 354 {
 355   "binary",                     /* name */
 356   bfd_target_unknown_flavour,   /* flavour */
 357   BFD_ENDIAN_UNKNOWN,           /* byteorder */
 358   BFD_ENDIAN_UNKNOWN,           /* header_byteorder */
 359   EXEC_P,                       /* object_flags */
 360   (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE | SEC_DATA
 361    | SEC_ROM | SEC_HAS_CONTENTS), /* section_flags */
 362   0,                            /* symbol_leading_char */
 363   ' ',                          /* ar_pad_char */
 364   16,                           /* ar_max_namelen */
 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,   /* data */
 368   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 369   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 370   bfd_getb16, bfd_getb_signed_16, bfd_putb16,   /* hdrs */
 371   {                             /* bfd_check_format */
 372     _bfd_dummy_target,
 373     binary_object_p,            /* bfd_check_format */
 374     _bfd_dummy_target,
 375     _bfd_dummy_target,
 376   },
 377   {                             /* bfd_set_format */
 378     bfd_false,
 379     binary_mkobject,
 380     bfd_false,
 381     bfd_false,
 382   },
 383   {                             /* bfd_write_contents */
 384     bfd_false,
 385     bfd_true,
 386     bfd_false,
 387     bfd_false,
 388   },
 389
 390   BFD_JUMP_TABLE_GENERIC (binary),
 391   BFD_JUMP_TABLE_COPY (_bfd_generic),
 392   BFD_JUMP_TABLE_CORE (_bfd_nocore),
 393   BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 394   BFD_JUMP_TABLE_SYMBOLS (binary),
 395   BFD_JUMP_TABLE_RELOCS (binary),
 396   BFD_JUMP_TABLE_WRITE (binary),
 397   BFD_JUMP_TABLE_LINK (binary),
 398   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 399
 400   NULL,
 401
 402   NULL
 403 };