1 /* BFD back-end for binary objects. 2 Copyright (C) 1994-2017 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 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 #define binary_get_symbol_version_string \ 194 _bfd_nosymbols_get_symbol_version_string 195 196 /* Get information about a symbol. */ 197 198 static void 199 binary_get_symbol_info (bfd *ignore_abfd ATTRIBUTE_UNUSED, 200 asymbol *symbol, 201 symbol_info *ret) 202 { 203 bfd_symbol_info (symbol, ret); 204 } 205 206 #define binary_bfd_is_local_label_name bfd_generic_is_local_label_name 207 #define binary_get_lineno _bfd_nosymbols_get_lineno 208 #define binary_find_nearest_line _bfd_nosymbols_find_nearest_line 209 #define binary_find_line _bfd_nosymbols_find_line 210 #define binary_find_inliner_info _bfd_nosymbols_find_inliner_info 211 #define binary_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol 212 #define binary_read_minisymbols _bfd_generic_read_minisymbols 213 #define binary_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol 214 #define binary_bfd_is_target_special_symbol ((bfd_boolean (*) (bfd *, asymbol *)) bfd_false) 215 216 /* Set the architecture of a binary file. */ 217 #define binary_set_arch_mach _bfd_generic_set_arch_mach 218 219 /* Write section contents of a binary file. */ 220 221 static bfd_boolean 222 binary_set_section_contents (bfd *abfd, 223 asection *sec, 224 const void * data, 225 file_ptr offset, 226 bfd_size_type size) 227 { 228 if (size == 0) 229 return TRUE; 230 231 if (! abfd->output_has_begun) 232 { 233 bfd_boolean found_low; 234 bfd_vma low; 235 asection *s; 236 237 /* The lowest section LMA sets the virtual address of the start 238 of the file. We use this to set the file position of all the 239 sections. */ 240 found_low = FALSE; 241 low = 0; 242 for (s = abfd->sections; s != NULL; s = s->next) 243 if (((s->flags 244 & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD)) 245 == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC)) 246 && (s->size > 0) 247 && (! found_low || s->lma < low)) 248 { 249 low = s->lma; 250 found_low = TRUE; 251 } 252 253 for (s = abfd->sections; s != NULL; s = s->next) 254 { 255 s->filepos = s->lma - low; 256 257 /* Skip following warning check for sections that will not 258 occupy file space. */ 259 if ((s->flags 260 & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD)) 261 != (SEC_HAS_CONTENTS | SEC_ALLOC) 262 || (s->size == 0)) 263 continue; 264 265 /* If attempting to generate a binary file from a bfd with 266 LMA's all over the place, huge (sparse?) binary files may 267 result. This condition attempts to detect this situation 268 and print a warning. Better heuristics would be nice to 269 have. */ 270 271 if (s->filepos < 0) 272 _bfd_error_handler 273 /* xgettext:c-format */ 274 (_("warning: writing section `%A' at huge (ie negative) " 275 "file offset 0x%lx."), 276 s, (unsigned long) s->filepos); 277 } 278 279 abfd->output_has_begun = TRUE; 280 } 281 282 /* We don't want to output anything for a section that is neither 283 loaded nor allocated. The contents of such a section are not 284 meaningful in the binary format. */ 285 if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0) 286 return TRUE; 287 if ((sec->flags & SEC_NEVER_LOAD) != 0) 288 return TRUE; 289 290 return _bfd_generic_set_section_contents (abfd, sec, data, offset, size); 291 } 292 293 /* No space is required for header information. */ 294 295 static int 296 binary_sizeof_headers (bfd *abfd ATTRIBUTE_UNUSED, 297 struct bfd_link_info *info ATTRIBUTE_UNUSED) 298 { 299 return 0; 300 } 301 302 #define binary_bfd_get_relocated_section_contents bfd_generic_get_relocated_section_contents 303 #define binary_bfd_relax_section bfd_generic_relax_section 304 #define binary_bfd_gc_sections bfd_generic_gc_sections 305 #define binary_bfd_lookup_section_flags bfd_generic_lookup_section_flags 306 #define binary_bfd_merge_sections bfd_generic_merge_sections 307 #define binary_bfd_is_group_section bfd_generic_is_group_section 308 #define binary_bfd_discard_group bfd_generic_discard_group 309 #define binary_section_already_linked _bfd_generic_section_already_linked 310 #define binary_bfd_define_common_symbol bfd_generic_define_common_symbol 311 #define binary_bfd_link_hash_table_create _bfd_generic_link_hash_table_create 312 #define binary_bfd_link_just_syms _bfd_generic_link_just_syms 313 #define binary_bfd_copy_link_hash_symbol_type _bfd_generic_copy_link_hash_symbol_type 314 #define binary_bfd_link_add_symbols _bfd_generic_link_add_symbols 315 #define binary_bfd_final_link _bfd_generic_final_link 316 #define binary_bfd_link_split_section _bfd_generic_link_split_section 317 #define binary_get_section_contents_in_window _bfd_generic_get_section_contents_in_window 318 #define binary_bfd_link_check_relocs _bfd_generic_link_check_relocs 319 320 const bfd_target binary_vec = 321 { 322 "binary", /* name */ 323 bfd_target_unknown_flavour, /* flavour */ 324 BFD_ENDIAN_UNKNOWN, /* byteorder */ 325 BFD_ENDIAN_UNKNOWN, /* header_byteorder */ 326 EXEC_P, /* object_flags */ 327 (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE | SEC_DATA 328 | SEC_ROM | SEC_HAS_CONTENTS), /* section_flags */ 329 0, /* symbol_leading_char */ 330 ' ', /* ar_pad_char */ 331 16, /* ar_max_namelen */ 332 255, /* match priority. */ 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, /* data */ 336 bfd_getb64, bfd_getb_signed_64, bfd_putb64, 337 bfd_getb32, bfd_getb_signed_32, bfd_putb32, 338 bfd_getb16, bfd_getb_signed_16, bfd_putb16, /* hdrs */ 339 { /* bfd_check_format */ 340 _bfd_dummy_target, 341 binary_object_p, 342 _bfd_dummy_target, 343 _bfd_dummy_target, 344 }, 345 { /* bfd_set_format */ 346 bfd_false, 347 binary_mkobject, 348 bfd_false, 349 bfd_false, 350 }, 351 { /* bfd_write_contents */ 352 bfd_false, 353 bfd_true, 354 bfd_false, 355 bfd_false, 356 }, 357 358 BFD_JUMP_TABLE_GENERIC (binary), 359 BFD_JUMP_TABLE_COPY (_bfd_generic), 360 BFD_JUMP_TABLE_CORE (_bfd_nocore), 361 BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive), 362 BFD_JUMP_TABLE_SYMBOLS (binary), 363 BFD_JUMP_TABLE_RELOCS (_bfd_norelocs), 364 BFD_JUMP_TABLE_WRITE (binary), 365 BFD_JUMP_TABLE_LINK (binary), 366 BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic), 367 368 NULL, 369 370 NULL 371 }; 372