1 /* BFD back-end for binary objects. 2 Copyright (C) 1994-2014 Free Software Foundation, Inc. 3 Written by Ian Lance Taylor, Cygnus Support, <ian (at) 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 3 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., 51 Franklin Street - Fifth Floor, Boston, 20 MA 02110-1301, 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 "sysdep.h" 36 #include "bfd.h" 37 #include "safe-ctype.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 /* Create a binary object. Invoked via bfd_set_format. */ 45 46 static bfd_boolean 47 binary_mkobject (bfd *abfd ATTRIBUTE_UNUSED) 48 { 49 return TRUE; 50 } 51 52 /* Any file may be considered to be a binary file, provided the target 53 was not defaulted. That is, it must be explicitly specified as 54 being binary. */ 55 56 static const bfd_target * 57 binary_object_p (bfd *abfd) 58 { 59 struct stat statbuf; 60 asection *sec; 61 flagword flags; 62 63 if (abfd->target_defaulted) 64 { 65 bfd_set_error (bfd_error_wrong_format); 66 return NULL; 67 } 68 69 abfd->symcount = BIN_SYMS; 70 71 /* Find the file size. */ 72 if (bfd_stat (abfd, &statbuf) < 0) 73 { 74 bfd_set_error (bfd_error_system_call); 75 return NULL; 76 } 77 78 /* One data section. */ 79 flags = SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS; 80 sec = bfd_make_section_with_flags (abfd, ".data", flags); 81 if (sec == NULL) 82 return NULL; 83 sec->vma = 0; 84 sec->size = statbuf.st_size; 85 sec->filepos = 0; 86 87 abfd->tdata.any = (void *) sec; 88 89 return abfd->xvec; 90 } 91 92 #define binary_close_and_cleanup _bfd_generic_close_and_cleanup 93 #define binary_bfd_free_cached_info _bfd_generic_bfd_free_cached_info 94 #define binary_new_section_hook _bfd_generic_new_section_hook 95 96 /* Get contents of the only section. */ 97 98 static bfd_boolean 99 binary_get_section_contents (bfd *abfd, 100 asection *section ATTRIBUTE_UNUSED, 101 void * location, 102 file_ptr offset, 103 bfd_size_type count) 104 { 105 if (bfd_seek (abfd, offset, SEEK_SET) != 0 106 || bfd_bread (location, count, abfd) != count) 107 return FALSE; 108 return TRUE; 109 } 110 111 /* Return the amount of memory needed to read the symbol table. */ 112 113 static long 114 binary_get_symtab_upper_bound (bfd *abfd ATTRIBUTE_UNUSED) 115 { 116 return (BIN_SYMS + 1) * sizeof (asymbol *); 117 } 118 119 /* Create a symbol name based on the bfd's filename. */ 120 121 static char * 122 mangle_name (bfd *abfd, char *suffix) 123 { 124 bfd_size_type size; 125 char *buf; 126 char *p; 127 128 size = (strlen (bfd_get_filename (abfd)) 129 + strlen (suffix) 130 + sizeof "_binary__"); 131 132 buf = (char *) bfd_alloc (abfd, size); 133 if (buf == NULL) 134 return ""; 135 136 sprintf (buf, "_binary_%s_%s", bfd_get_filename (abfd), suffix); 137 138 /* Change any non-alphanumeric characters to underscores. */ 139 for (p = buf; *p; p++) 140 if (! ISALNUM (*p)) 141 *p = '_'; 142 143 return buf; 144 } 145 146 /* Return the symbol table. */ 147 148 static long 149 binary_canonicalize_symtab (bfd *abfd, asymbol **alocation) 150 { 151 asection *sec = (asection *) abfd->tdata.any; 152 asymbol *syms; 153 unsigned int i; 154 bfd_size_type amt = BIN_SYMS * sizeof (asymbol); 155 156 syms = (asymbol *) bfd_alloc (abfd, amt); 157 if (syms == NULL) 158 return -1; 159 160 /* Start symbol. */ 161 syms[0].the_bfd = abfd; 162 syms[0].name = mangle_name (abfd, "start"); 163 syms[0].value = 0; 164 syms[0].flags = BSF_GLOBAL; 165 syms[0].section = sec; 166 syms[0].udata.p = NULL; 167 168 /* End symbol. */ 169 syms[1].the_bfd = abfd; 170 syms[1].name = mangle_name (abfd, "end"); 171 syms[1].value = sec->size; 172 syms[1].flags = BSF_GLOBAL; 173 syms[1].section = sec; 174 syms[1].udata.p = NULL; 175 176 /* Size symbol. */ 177 syms[2].the_bfd = abfd; 178 syms[2].name = mangle_name (abfd, "size"); 179 syms[2].value = sec->size; 180 syms[2].flags = BSF_GLOBAL; 181 syms[2].section = bfd_abs_section_ptr; 182 syms[2].udata.p = NULL; 183 184 for (i = 0; i < BIN_SYMS; i++) 185 *alocation++ = syms++; 186 *alocation = NULL; 187 188 return BIN_SYMS; 189 } 190 191 #define binary_make_empty_symbol _bfd_generic_make_empty_symbol 192 #define binary_print_symbol _bfd_nosymbols_print_symbol 193 194 /* Get information about a symbol. */ 195 196 static void 197 binary_get_symbol_info (bfd *ignore_abfd ATTRIBUTE_UNUSED, 198 asymbol *symbol, 199 symbol_info *ret) 200 { 201 bfd_symbol_info (symbol, ret); 202 } 203 204 #define binary_bfd_is_local_label_name bfd_generic_is_local_label_name 205 #define binary_get_lineno _bfd_nosymbols_get_lineno 206 #define binary_find_nearest_line _bfd_nosymbols_find_nearest_line 207 #define binary_find_line _bfd_nosymbols_find_line 208 #define binary_find_inliner_info _bfd_nosymbols_find_inliner_info 209 #define binary_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol 210 #define binary_read_minisymbols _bfd_generic_read_minisymbols 211 #define binary_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol 212 #define binary_bfd_is_target_special_symbol ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false) 213 214 /* Set the architecture of a binary file. */ 215 #define binary_set_arch_mach _bfd_generic_set_arch_mach 216 217 /* Write section contents of a binary file. */ 218 219 static bfd_boolean 220 binary_set_section_contents (bfd *abfd, 221 asection *sec, 222 const void * data, 223 file_ptr offset, 224 bfd_size_type size) 225 { 226 if (size == 0) 227 return TRUE; 228 229 if (! abfd->output_has_begun) 230 { 231 bfd_boolean found_low; 232 bfd_vma low; 233 asection *s; 234 235 /* The lowest section LMA sets the virtual address of the start 236 of the file. We use this to set the file position of all the 237 sections. */ 238 found_low = FALSE; 239 low = 0; 240 for (s = abfd->sections; s != NULL; s = s->next) 241 if (((s->flags 242 & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD)) 243 == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC)) 244 && (s->size > 0) 245 && (! found_low || s->lma < low)) 246 { 247 low = s->lma; 248 found_low = TRUE; 249 } 250 251 for (s = abfd->sections; s != NULL; s = s->next) 252 { 253 s->filepos = s->lma - low; 254 255 /* Skip following warning check for sections that will not 256 occupy file space. */ 257 if ((s->flags 258 & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD)) 259 != (SEC_HAS_CONTENTS | SEC_ALLOC) 260 || (s->size == 0)) 261 continue; 262 263 /* If attempting to generate a binary file from a bfd with 264 LMA's all over the place, huge (sparse?) binary files may 265 result. This condition attempts to detect this situation 266 and print a warning. Better heuristics would be nice to 267 have. */ 268 269 if (s->filepos < 0) 270 (*_bfd_error_handler) 271 (_("Warning: Writing section `%s' to huge (ie negative) file offset 0x%lx."), 272 bfd_get_section_name (abfd, s), 273 (unsigned long) s->filepos); 274 } 275 276 abfd->output_has_begun = TRUE; 277 } 278 279 /* We don't want to output anything for a section that is neither 280 loaded nor allocated. The contents of such a section are not 281 meaningful in the binary format. */ 282 if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0) 283 return TRUE; 284 if ((sec->flags & SEC_NEVER_LOAD) != 0) 285 return TRUE; 286 287 return _bfd_generic_set_section_contents (abfd, sec, data, offset, size); 288 } 289 290 /* No space is required for header information. */ 291 292 static int 293 binary_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED, 294 struct bfd_link_info *info ATTRIBUTE_UNUSED) 295 { 296 return 0; 297 } 298 299 #define binary_bfd_get_relocated_section_contents bfd_generic_get_relocated_section_contents 300 #define binary_bfd_relax_section bfd_generic_relax_section 301 #define binary_bfd_gc_sections bfd_generic_gc_sections 302 #define binary_bfd_lookup_section_flags bfd_generic_lookup_section_flags 303 #define binary_bfd_merge_sections bfd_generic_merge_sections 304 #define binary_bfd_is_group_section bfd_generic_is_group_section 305 #define binary_bfd_discard_group bfd_generic_discard_group 306 #define binary_section_already_linked _bfd_generic_section_already_linked 307 #define binary_bfd_define_common_symbol bfd_generic_define_common_symbol 308 #define binary_bfd_link_hash_table_create _bfd_generic_link_hash_table_create 309 #define binary_bfd_link_just_syms _bfd_generic_link_just_syms 310 #define binary_bfd_copy_link_hash_symbol_type \ 311 _bfd_generic_copy_link_hash_symbol_type 312 #define binary_bfd_link_add_symbols _bfd_generic_link_add_symbols 313 #define binary_bfd_final_link _bfd_generic_final_link 314 #define binary_bfd_link_split_section _bfd_generic_link_split_section 315 #define binary_get_section_contents_in_window _bfd_generic_get_section_contents_in_window 316 317 const bfd_target binary_vec = 318 { 319 "binary", /* name */ 320 bfd_target_unknown_flavour, /* flavour */ 321 BFD_ENDIAN_UNKNOWN, /* byteorder */ 322 BFD_ENDIAN_UNKNOWN, /* header_byteorder */ 323 EXEC_P, /* object_flags */ 324 (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE | SEC_DATA 325 | SEC_ROM | SEC_HAS_CONTENTS), /* section_flags */ 326 0, /* symbol_leading_char */ 327 ' ', /* ar_pad_char */ 328 16, /* ar_max_namelen */ 329 255, /* match priority. */ 330 bfd_getb64, bfd_getb_signed_64, bfd_putb64, 331 bfd_getb32, bfd_getb_signed_32, bfd_putb32, 332 bfd_getb16, bfd_getb_signed_16, bfd_putb16, /* data */ 333 bfd_getb64, bfd_getb_signed_64, bfd_putb64, 334 bfd_getb32, bfd_getb_signed_32, bfd_putb32, 335 bfd_getb16, bfd_getb_signed_16, bfd_putb16, /* hdrs */ 336 { /* bfd_check_format */ 337 _bfd_dummy_target, 338 binary_object_p, 339 _bfd_dummy_target, 340 _bfd_dummy_target, 341 }, 342 { /* bfd_set_format */ 343 bfd_false, 344 binary_mkobject, 345 bfd_false, 346 bfd_false, 347 }, 348 { /* bfd_write_contents */ 349 bfd_false, 350 bfd_true, 351 bfd_false, 352 bfd_false, 353 }, 354 355 BFD_JUMP_TABLE_GENERIC (binary), 356 BFD_JUMP_TABLE_COPY (_bfd_generic), 357 BFD_JUMP_TABLE_CORE (_bfd_nocore), 358 BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive), 359 BFD_JUMP_TABLE_SYMBOLS (binary), 360 BFD_JUMP_TABLE_RELOCS (_bfd_norelocs), 361 BFD_JUMP_TABLE_WRITE (binary), 362 BFD_JUMP_TABLE_LINK (binary), 363 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic), 364 365 NULL, 366 367 NULL 368 }; 369
