1 /* BFD back-end for binary objects. 2 Copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 3 2004, 2005, 2006, 2007 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 3 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., 51 Franklin Street - Fifth Floor, Boston, 21 MA 02110-1301, 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 "sysdep.h" 37 #include "bfd.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 /* Set by external programs - specifies the BFD architecture and 46 machine number to be uses when creating binary BFDs. */ 47 enum bfd_architecture bfd_external_binary_architecture = bfd_arch_unknown; 48 unsigned long bfd_external_machine = 0; 49 50 /* Create a binary object. Invoked via bfd_set_format. */ 51 52 static bfd_boolean 53 binary_mkobject (bfd *abfd ATTRIBUTE_UNUSED) 54 { 55 return TRUE; 56 } 57 58 /* Any file may be considered to be a binary file, provided the target 59 was not defaulted. That is, it must be explicitly specified as 60 being binary. */ 61 62 static const bfd_target * 63 binary_object_p (bfd *abfd) 64 { 65 struct stat statbuf; 66 asection *sec; 67 flagword flags; 68 69 if (abfd->target_defaulted) 70 { 71 bfd_set_error (bfd_error_wrong_format); 72 return NULL; 73 } 74 75 abfd->symcount = BIN_SYMS; 76 77 /* Find the file size. */ 78 if (bfd_stat (abfd, &statbuf) < 0) 79 { 80 bfd_set_error (bfd_error_system_call); 81 return NULL; 82 } 83 84 /* One data section. */ 85 flags = SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS; 86 sec = bfd_make_section_with_flags (abfd, ".data", flags); 87 if (sec == NULL) 88 return NULL; 89 sec->vma = 0; 90 sec->size = statbuf.st_size; 91 sec->filepos = 0; 92 93 abfd->tdata.any = (void *) sec; 94 95 if (bfd_get_arch_info (abfd) != NULL) 96 { 97 if ((bfd_get_arch_info (abfd)->arch == bfd_arch_unknown) 98 && (bfd_external_binary_architecture != bfd_arch_unknown)) 99 bfd_set_arch_info (abfd, bfd_lookup_arch 100 (bfd_external_binary_architecture, bfd_external_machine)); 101 } 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 bfd_boolean 113 binary_get_section_contents (bfd *abfd, 114 asection *section ATTRIBUTE_UNUSED, 115 void * location, 116 file_ptr offset, 117 bfd_size_type count) 118 { 119 if (bfd_seek (abfd, offset, SEEK_SET) != 0 120 || bfd_bread (location, count, abfd) != count) 121 return FALSE; 122 return TRUE; 123 } 124 125 /* Return the amount of memory needed to read the symbol table. */ 126 127 static long 128 binary_get_symtab_upper_bound (bfd *abfd ATTRIBUTE_UNUSED) 129 { 130 return (BIN_SYMS + 1) * sizeof (asymbol *); 131 } 132 133 /* Create a symbol name based on the bfd's filename. */ 134 135 static char * 136 mangle_name (bfd *abfd, char *suffix) 137 { 138 bfd_size_type size; 139 char *buf; 140 char *p; 141 142 size = (strlen (bfd_get_filename (abfd)) 143 + strlen (suffix) 144 + sizeof "_binary__"); 145 146 buf = bfd_alloc (abfd, size); 147 if (buf == NULL) 148 return ""; 149 150 sprintf (buf, "_binary_%s_%s", bfd_get_filename (abfd), suffix); 151 152 /* Change any non-alphanumeric characters to underscores. */ 153 for (p = buf; *p; p++) 154 if (! ISALNUM (*p)) 155 *p = '_'; 156 157 return buf; 158 } 159 160 /* Return the symbol table. */ 161 162 static long 163 binary_canonicalize_symtab (bfd *abfd, asymbol **alocation) 164 { 165 asection *sec = (asection *) abfd->tdata.any; 166 asymbol *syms; 167 unsigned int i; 168 bfd_size_type amt = BIN_SYMS * sizeof (asymbol); 169 170 syms = bfd_alloc (abfd, amt); 171 if (syms == NULL) 172 return -1; 173 174 /* Start symbol. */ 175 syms[0].the_bfd = abfd; 176 syms[0].name = mangle_name (abfd, "start"); 177 syms[0].value = 0; 178 syms[0].flags = BSF_GLOBAL; 179 syms[0].section = sec; 180 syms[0].udata.p = NULL; 181 182 /* End symbol. */ 183 syms[1].the_bfd = abfd; 184 syms[1].name = mangle_name (abfd, "end"); 185 syms[1].value = sec->size; 186 syms[1].flags = BSF_GLOBAL; 187 syms[1].section = sec; 188 syms[1].udata.p = NULL; 189 190 /* Size symbol. */ 191 syms[2].the_bfd = abfd; 192 syms[2].name = mangle_name (abfd, "size"); 193 syms[2].value = sec->size; 194 syms[2].flags = BSF_GLOBAL; 195 syms[2].section = bfd_abs_section_ptr; 196 syms[2].udata.p = NULL; 197 198 for (i = 0; i < BIN_SYMS; i++) 199 *alocation++ = syms++; 200 *alocation = NULL; 201 202 return BIN_SYMS; 203 } 204 205 #define binary_make_empty_symbol _bfd_generic_make_empty_symbol 206 #define binary_print_symbol _bfd_nosymbols_print_symbol 207 208 /* Get information about a symbol. */ 209 210 static void 211 binary_get_symbol_info (bfd *ignore_abfd ATTRIBUTE_UNUSED, 212 asymbol *symbol, 213 symbol_info *ret) 214 { 215 bfd_symbol_info (symbol, ret); 216 } 217 218 #define binary_bfd_is_local_label_name bfd_generic_is_local_label_name 219 #define binary_get_lineno _bfd_nosymbols_get_lineno 220 #define binary_find_nearest_line _bfd_nosymbols_find_nearest_line 221 #define binary_find_inliner_info _bfd_nosymbols_find_inliner_info 222 #define binary_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol 223 #define binary_read_minisymbols _bfd_generic_read_minisymbols 224 #define binary_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol 225 #define binary_bfd_is_target_special_symbol ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false) 226 227 /* Set the architecture of a binary file. */ 228 #define binary_set_arch_mach _bfd_generic_set_arch_mach 229 230 /* Write section contents of a binary file. */ 231 232 static bfd_boolean 233 binary_set_section_contents (bfd *abfd, 234 asection *sec, 235 const void * data, 236 file_ptr offset, 237 bfd_size_type size) 238 { 239 if (size == 0) 240 return TRUE; 241 242 if (! abfd->output_has_begun) 243 { 244 bfd_boolean found_low; 245 bfd_vma low; 246 asection *s; 247 248 /* The lowest section LMA sets the virtual address of the start 249 of the file. We use this to set the file position of all the 250 sections. */ 251 found_low = FALSE; 252 low = 0; 253 for (s = abfd->sections; s != NULL; s = s->next) 254 if (((s->flags 255 & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD)) 256 == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC)) 257 && (s->size > 0) 258 && (! found_low || s->lma < low)) 259 { 260 low = s->lma; 261 found_low = TRUE; 262 } 263 264 for (s = abfd->sections; s != NULL; s = s->next) 265 { 266 s->filepos = s->lma - low; 267 268 /* Skip following warning check for sections that will not 269 occupy file space. */ 270 if ((s->flags 271 & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD)) 272 != (SEC_HAS_CONTENTS | SEC_ALLOC) 273 || (s->size == 0)) 274 continue; 275 276 /* If attempting to generate a binary file from a bfd with 277 LMA's all over the place, huge (sparse?) binary files may 278 result. This condition attempts to detect this situation 279 and print a warning. Better heuristics would be nice to 280 have. */ 281 282 if (s->filepos < 0) 283 (*_bfd_error_handler) 284 (_("Warning: Writing section `%s' to huge (ie negative) file offset 0x%lx."), 285 bfd_get_section_name (abfd, s), 286 (unsigned long) s->filepos); 287 } 288 289 abfd->output_has_begun = TRUE; 290 } 291 292 /* We don't want to output anything for a section that is neither 293 loaded nor allocated. The contents of such a section are not 294 meaningful in the binary format. */ 295 if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0) 296 return TRUE; 297 if ((sec->flags & SEC_NEVER_LOAD) != 0) 298 return TRUE; 299 300 return _bfd_generic_set_section_contents (abfd, sec, data, offset, size); 301 } 302 303 /* No space is required for header information. */ 304 305 static int 306 binary_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED, 307 struct bfd_link_info *info ATTRIBUTE_UNUSED) 308 { 309 return 0; 310 } 311 312 #define binary_bfd_get_relocated_section_contents bfd_generic_get_relocated_section_contents 313 #define binary_bfd_relax_section bfd_generic_relax_section 314 #define binary_bfd_gc_sections bfd_generic_gc_sections 315 #define binary_bfd_merge_sections bfd_generic_merge_sections 316 #define binary_bfd_is_group_section bfd_generic_is_group_section 317 #define binary_bfd_discard_group bfd_generic_discard_group 318 #define binary_section_already_linked _bfd_generic_section_already_linked 319 #define binary_bfd_link_hash_table_create _bfd_generic_link_hash_table_create 320 #define binary_bfd_link_hash_table_free _bfd_generic_link_hash_table_free 321 #define binary_bfd_link_just_syms _bfd_generic_link_just_syms 322 #define binary_bfd_link_add_symbols _bfd_generic_link_add_symbols 323 #define binary_bfd_final_link _bfd_generic_final_link 324 #define binary_bfd_link_split_section _bfd_generic_link_split_section 325 #define binary_get_section_contents_in_window _bfd_generic_get_section_contents_in_window 326 327 const bfd_target binary_vec = 328 { 329 "binary", /* name */ 330 bfd_target_unknown_flavour, /* flavour */ 331 BFD_ENDIAN_UNKNOWN, /* byteorder */ 332 BFD_ENDIAN_UNKNOWN, /* header_byteorder */ 333 EXEC_P, /* object_flags */ 334 (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE | SEC_DATA 335 | SEC_ROM | SEC_HAS_CONTENTS), /* section_flags */ 336 0, /* symbol_leading_char */ 337 ' ', /* ar_pad_char */ 338 16, /* ar_max_namelen */ 339 bfd_getb64, bfd_getb_signed_64, bfd_putb64, 340 bfd_getb32, bfd_getb_signed_32, bfd_putb32, 341 bfd_getb16, bfd_getb_signed_16, bfd_putb16, /* data */ 342 bfd_getb64, bfd_getb_signed_64, bfd_putb64, 343 bfd_getb32, bfd_getb_signed_32, bfd_putb32, 344 bfd_getb16, bfd_getb_signed_16, bfd_putb16, /* hdrs */ 345 { /* bfd_check_format */ 346 _bfd_dummy_target, 347 binary_object_p, 348 _bfd_dummy_target, 349 _bfd_dummy_target, 350 }, 351 { /* bfd_set_format */ 352 bfd_false, 353 binary_mkobject, 354 bfd_false, 355 bfd_false, 356 }, 357 { /* bfd_write_contents */ 358 bfd_false, 359 bfd_true, 360 bfd_false, 361 bfd_false, 362 }, 363 364 BFD_JUMP_TABLE_GENERIC (binary), 365 BFD_JUMP_TABLE_COPY (_bfd_generic), 366 BFD_JUMP_TABLE_CORE (_bfd_nocore), 367 BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive), 368 BFD_JUMP_TABLE_SYMBOLS (binary), 369 BFD_JUMP_TABLE_RELOCS (_bfd_norelocs), 370 BFD_JUMP_TABLE_WRITE (binary), 371 BFD_JUMP_TABLE_LINK (binary), 372 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic), 373 374 NULL, 375 376 NULL 377 }; 378