1 /* ELF attributes support (based on ARM EABI attributes). 2 Copyright 2005, 2006, 2007, 2009 3 Free Software Foundation, Inc. 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 #include "sysdep.h" 23 #include "bfd.h" 24 #include "libiberty.h" 25 #include "libbfd.h" 26 #include "elf-bfd.h" 27 28 /* Return the number of bytes needed by I in uleb128 format. */ 29 static int 30 uleb128_size (unsigned int i) 31 { 32 int size; 33 size = 1; 34 while (i >= 0x80) 35 { 36 i >>= 7; 37 size++; 38 } 39 return size; 40 } 41 42 /* Return TRUE if the attribute has the default value (0/""). */ 43 static bfd_boolean 44 is_default_attr (obj_attribute *attr) 45 { 46 if (ATTR_TYPE_HAS_INT_VAL (attr->type) && attr->i != 0) 47 return FALSE; 48 if (ATTR_TYPE_HAS_STR_VAL (attr->type) && attr->s && *attr->s) 49 return FALSE; 50 if (ATTR_TYPE_HAS_NO_DEFAULT (attr->type)) 51 return FALSE; 52 53 return TRUE; 54 } 55 56 /* Return the size of a single attribute. */ 57 static bfd_vma 58 obj_attr_size (int tag, obj_attribute *attr) 59 { 60 bfd_vma size; 61 62 if (is_default_attr (attr)) 63 return 0; 64 65 size = uleb128_size (tag); 66 if (ATTR_TYPE_HAS_INT_VAL (attr->type)) 67 size += uleb128_size (attr->i); 68 if (ATTR_TYPE_HAS_STR_VAL (attr->type)) 69 size += strlen ((char *)attr->s) + 1; 70 return size; 71 } 72 73 /* Return the vendor name for a given object attributes section. */ 74 static const char * 75 vendor_obj_attr_name (bfd *abfd, int vendor) 76 { 77 return (vendor == OBJ_ATTR_PROC 78 ? get_elf_backend_data (abfd)->obj_attrs_vendor 79 : "gnu"); 80 } 81 82 /* Return the size of the object attributes section for VENDOR 83 (OBJ_ATTR_PROC or OBJ_ATTR_GNU), or 0 if there are no attributes 84 for that vendor to record and the vendor is OBJ_ATTR_GNU. */ 85 static bfd_vma 86 vendor_obj_attr_size (bfd *abfd, int vendor) 87 { 88 bfd_vma size; 89 obj_attribute *attr; 90 obj_attribute_list *list; 91 int i; 92 const char *vendor_name = vendor_obj_attr_name (abfd, vendor); 93 94 if (!vendor_name) 95 return 0; 96 97 attr = elf_known_obj_attributes (abfd)[vendor]; 98 size = 0; 99 for (i = 4; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++) 100 size += obj_attr_size (i, &attr[i]); 101 102 for (list = elf_other_obj_attributes (abfd)[vendor]; 103 list; 104 list = list->next) 105 size += obj_attr_size (list->tag, &list->attr); 106 107 /* <size> <vendor_name> NUL 0x1 <size> */ 108 return ((size || vendor == OBJ_ATTR_PROC) 109 ? size + 10 + strlen (vendor_name) 110 : 0); 111 } 112 113 /* Return the size of the object attributes section. */ 114 bfd_vma 115 bfd_elf_obj_attr_size (bfd *abfd) 116 { 117 bfd_vma size; 118 119 size = vendor_obj_attr_size (abfd, OBJ_ATTR_PROC); 120 size += vendor_obj_attr_size (abfd, OBJ_ATTR_GNU); 121 122 /* 'A' <sections for each vendor> */ 123 return (size ? size + 1 : 0); 124 } 125 126 /* Write VAL in uleb128 format to P, returning a pointer to the 127 following byte. */ 128 static bfd_byte * 129 write_uleb128 (bfd_byte *p, unsigned int val) 130 { 131 bfd_byte c; 132 do 133 { 134 c = val & 0x7f; 135 val >>= 7; 136 if (val) 137 c |= 0x80; 138 *(p++) = c; 139 } 140 while (val); 141 return p; 142 } 143 144 /* Write attribute ATTR to butter P, and return a pointer to the following 145 byte. */ 146 static bfd_byte * 147 write_obj_attribute (bfd_byte *p, int tag, obj_attribute *attr) 148 { 149 /* Suppress default entries. */ 150 if (is_default_attr (attr)) 151 return p; 152 153 p = write_uleb128 (p, tag); 154 if (ATTR_TYPE_HAS_INT_VAL (attr->type)) 155 p = write_uleb128 (p, attr->i); 156 if (ATTR_TYPE_HAS_STR_VAL (attr->type)) 157 { 158 int len; 159 160 len = strlen (attr->s) + 1; 161 memcpy (p, attr->s, len); 162 p += len; 163 } 164 165 return p; 166 } 167 168 /* Write the contents of the object attributes section (length SIZE) 169 for VENDOR to CONTENTS. */ 170 static void 171 vendor_set_obj_attr_contents (bfd *abfd, bfd_byte *contents, bfd_vma size, 172 int vendor) 173 { 174 bfd_byte *p; 175 obj_attribute *attr; 176 obj_attribute_list *list; 177 int i; 178 const char *vendor_name = vendor_obj_attr_name (abfd, vendor); 179 size_t vendor_length = strlen (vendor_name) + 1; 180 181 p = contents; 182 bfd_put_32 (abfd, size, p); 183 p += 4; 184 memcpy (p, vendor_name, vendor_length); 185 p += vendor_length; 186 *(p++) = Tag_File; 187 bfd_put_32 (abfd, size - 4 - vendor_length, p); 188 p += 4; 189 190 attr = elf_known_obj_attributes (abfd)[vendor]; 191 for (i = 4; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++) 192 { 193 int tag = i; 194 if (get_elf_backend_data (abfd)->obj_attrs_order) 195 tag = get_elf_backend_data (abfd)->obj_attrs_order (i); 196 p = write_obj_attribute (p, tag, &attr[tag]); 197 } 198 199 for (list = elf_other_obj_attributes (abfd)[vendor]; 200 list; 201 list = list->next) 202 p = write_obj_attribute (p, list->tag, &list->attr); 203 } 204 205 /* Write the contents of the object attributes section to CONTENTS. */ 206 void 207 bfd_elf_set_obj_attr_contents (bfd *abfd, bfd_byte *contents, bfd_vma size) 208 { 209 bfd_byte *p; 210 int vendor; 211 bfd_vma my_size; 212 213 p = contents; 214 *(p++) = 'A'; 215 my_size = 1; 216 for (vendor = OBJ_ATTR_FIRST; vendor <= OBJ_ATTR_LAST; vendor++) 217 { 218 bfd_vma vendor_size = vendor_obj_attr_size (abfd, vendor); 219 if (vendor_size) 220 vendor_set_obj_attr_contents (abfd, p, vendor_size, vendor); 221 p += vendor_size; 222 my_size += vendor_size; 223 } 224 225 if (size != my_size) 226 abort (); 227 } 228 229 /* Allocate/find an object attribute. */ 230 static obj_attribute * 231 elf_new_obj_attr (bfd *abfd, int vendor, int tag) 232 { 233 obj_attribute *attr; 234 obj_attribute_list *list; 235 obj_attribute_list *p; 236 obj_attribute_list **lastp; 237 238 239 if (tag < NUM_KNOWN_OBJ_ATTRIBUTES) 240 { 241 /* Known tags are preallocated. */ 242 attr = &elf_known_obj_attributes (abfd)[vendor][tag]; 243 } 244 else 245 { 246 /* Create a new tag. */ 247 list = (obj_attribute_list *) 248 bfd_alloc (abfd, sizeof (obj_attribute_list)); 249 memset (list, 0, sizeof (obj_attribute_list)); 250 list->tag = tag; 251 /* Keep the tag list in order. */ 252 lastp = &elf_other_obj_attributes (abfd)[vendor]; 253 for (p = *lastp; p; p = p->next) 254 { 255 if (tag < p->tag) 256 break; 257 lastp = &p->next; 258 } 259 list->next = *lastp; 260 *lastp = list; 261 attr = &list->attr; 262 } 263 264 return attr; 265 } 266 267 /* Return the value of an integer object attribute. */ 268 int 269 bfd_elf_get_obj_attr_int (bfd *abfd, int vendor, int tag) 270 { 271 obj_attribute_list *p; 272 273 if (tag < NUM_KNOWN_OBJ_ATTRIBUTES) 274 { 275 /* Known tags are preallocated. */ 276 return elf_known_obj_attributes (abfd)[vendor][tag].i; 277 } 278 else 279 { 280 for (p = elf_other_obj_attributes (abfd)[vendor]; 281 p; 282 p = p->next) 283 { 284 if (tag == p->tag) 285 return p->attr.i; 286 if (tag < p->tag) 287 break; 288 } 289 return 0; 290 } 291 } 292 293 /* Add an integer object attribute. */ 294 void 295 bfd_elf_add_obj_attr_int (bfd *abfd, int vendor, int tag, unsigned int i) 296 { 297 obj_attribute *attr; 298 299 attr = elf_new_obj_attr (abfd, vendor, tag); 300 attr->type = _bfd_elf_obj_attrs_arg_type (abfd, vendor, tag); 301 attr->i = i; 302 } 303 304 /* Duplicate an object attribute string value. */ 305 char * 306 _bfd_elf_attr_strdup (bfd *abfd, const char * s) 307 { 308 char * p; 309 int len; 310 311 len = strlen (s) + 1; 312 p = (char *) bfd_alloc (abfd, len); 313 return (char *) memcpy (p, s, len); 314 } 315 316 /* Add a string object attribute. */ 317 void 318 bfd_elf_add_obj_attr_string (bfd *abfd, int vendor, int tag, const char *s) 319 { 320 obj_attribute *attr; 321 322 attr = elf_new_obj_attr (abfd, vendor, tag); 323 attr->type = _bfd_elf_obj_attrs_arg_type (abfd, vendor, tag); 324 attr->s = _bfd_elf_attr_strdup (abfd, s); 325 } 326 327 /* Add a int+string object attribute. */ 328 void 329 bfd_elf_add_obj_attr_int_string (bfd *abfd, int vendor, int tag, 330 unsigned int i, const char *s) 331 { 332 obj_attribute *attr; 333 334 attr = elf_new_obj_attr (abfd, vendor, tag); 335 attr->type = _bfd_elf_obj_attrs_arg_type (abfd, vendor, tag); 336 attr->i = i; 337 attr->s = _bfd_elf_attr_strdup (abfd, s); 338 } 339 340 /* Copy the object attributes from IBFD to OBFD. */ 341 void 342 _bfd_elf_copy_obj_attributes (bfd *ibfd, bfd *obfd) 343 { 344 obj_attribute *in_attr; 345 obj_attribute *out_attr; 346 obj_attribute_list *list; 347 int i; 348 int vendor; 349 350 for (vendor = OBJ_ATTR_FIRST; vendor <= OBJ_ATTR_LAST; vendor++) 351 { 352 in_attr = &elf_known_obj_attributes (ibfd)[vendor][4]; 353 out_attr = &elf_known_obj_attributes (obfd)[vendor][4]; 354 for (i = 4; i < NUM_KNOWN_OBJ_ATTRIBUTES; i++) 355 { 356 out_attr->type = in_attr->type; 357 out_attr->i = in_attr->i; 358 if (in_attr->s && *in_attr->s) 359 out_attr->s = _bfd_elf_attr_strdup (obfd, in_attr->s); 360 in_attr++; 361 out_attr++; 362 } 363 364 for (list = elf_other_obj_attributes (ibfd)[vendor]; 365 list; 366 list = list->next) 367 { 368 in_attr = &list->attr; 369 switch (in_attr->type & (ATTR_TYPE_FLAG_INT_VAL | ATTR_TYPE_FLAG_STR_VAL)) 370 { 371 case ATTR_TYPE_FLAG_INT_VAL: 372 bfd_elf_add_obj_attr_int (obfd, vendor, list->tag, in_attr->i); 373 break; 374 case ATTR_TYPE_FLAG_STR_VAL: 375 bfd_elf_add_obj_attr_string (obfd, vendor, list->tag, 376 in_attr->s); 377 break; 378 case ATTR_TYPE_FLAG_INT_VAL | ATTR_TYPE_FLAG_STR_VAL: 379 bfd_elf_add_obj_attr_int_string (obfd, vendor, list->tag, 380 in_attr->i, in_attr->s); 381 break; 382 default: 383 abort (); 384 } 385 } 386 } 387 } 388 389 /* Determine whether a GNU object attribute tag takes an integer, a 390 string or both. */ 391 static int 392 gnu_obj_attrs_arg_type (int tag) 393 { 394 /* Except for Tag_compatibility, for GNU attributes we follow the 395 same rule ARM ones > 32 follow: odd-numbered tags take strings 396 and even-numbered tags take integers. In addition, tag & 2 is 397 nonzero for architecture-independent tags and zero for 398 architecture-dependent ones. */ 399 if (tag == Tag_compatibility) 400 return 3; 401 else 402 return (tag & 1) != 0 ? 2 : 1; 403 } 404 405 /* Determine what arguments an attribute tag takes. */ 406 int 407 _bfd_elf_obj_attrs_arg_type (bfd *abfd, int vendor, int tag) 408 { 409 switch (vendor) 410 { 411 case OBJ_ATTR_PROC: 412 return get_elf_backend_data (abfd)->obj_attrs_arg_type (tag); 413 break; 414 case OBJ_ATTR_GNU: 415 return gnu_obj_attrs_arg_type (tag); 416 break; 417 default: 418 abort (); 419 } 420 } 421 422 /* Parse an object attributes section. */ 423 void 424 _bfd_elf_parse_attributes (bfd *abfd, Elf_Internal_Shdr * hdr) 425 { 426 bfd_byte *contents; 427 bfd_byte *p; 428 bfd_vma len; 429 const char *std_section; 430 431 contents = (bfd_byte *) bfd_malloc (hdr->sh_size); 432 if (!contents) 433 return; 434 if (!bfd_get_section_contents (abfd, hdr->bfd_section, contents, 0, 435 hdr->sh_size)) 436 { 437 free (contents); 438 return; 439 } 440 p = contents; 441 std_section = get_elf_backend_data (abfd)->obj_attrs_vendor; 442 if (*(p++) == 'A') 443 { 444 len = hdr->sh_size - 1; 445 while (len > 0) 446 { 447 int namelen; 448 bfd_vma section_len; 449 int vendor; 450 451 section_len = bfd_get_32 (abfd, p); 452 p += 4; 453 if (section_len > len) 454 section_len = len; 455 len -= section_len; 456 namelen = strlen ((char *)p) + 1; 457 section_len -= namelen + 4; 458 if (std_section && strcmp ((char *)p, std_section) == 0) 459 vendor = OBJ_ATTR_PROC; 460 else if (strcmp ((char *)p, "gnu") == 0) 461 vendor = OBJ_ATTR_GNU; 462 else 463 { 464 /* Other vendor section. Ignore it. */ 465 p += namelen + section_len; 466 continue; 467 } 468 469 p += namelen; 470 while (section_len > 0) 471 { 472 int tag; 473 unsigned int n; 474 unsigned int val; 475 bfd_vma subsection_len; 476 bfd_byte *end; 477 478 tag = read_unsigned_leb128 (abfd, p, &n); 479 p += n; 480 subsection_len = bfd_get_32 (abfd, p); 481 p += 4; 482 if (subsection_len > section_len) 483 subsection_len = section_len; 484 section_len -= subsection_len; 485 subsection_len -= n + 4; 486 end = p + subsection_len; 487 switch (tag) 488 { 489 case Tag_File: 490 while (p < end) 491 { 492 int type; 493 494 tag = read_unsigned_leb128 (abfd, p, &n); 495 p += n; 496 type = _bfd_elf_obj_attrs_arg_type (abfd, vendor, tag); 497 switch (type & (ATTR_TYPE_FLAG_INT_VAL | ATTR_TYPE_FLAG_STR_VAL)) 498 { 499 case ATTR_TYPE_FLAG_INT_VAL | ATTR_TYPE_FLAG_STR_VAL: 500 val = read_unsigned_leb128 (abfd, p, &n); 501 p += n; 502 bfd_elf_add_obj_attr_int_string (abfd, vendor, tag, 503 val, (char *)p); 504 p += strlen ((char *)p) + 1; 505 break; 506 case ATTR_TYPE_FLAG_STR_VAL: 507 bfd_elf_add_obj_attr_string (abfd, vendor, tag, 508 (char *)p); 509 p += strlen ((char *)p) + 1; 510 break; 511 case ATTR_TYPE_FLAG_INT_VAL: 512 val = read_unsigned_leb128 (abfd, p, &n); 513 p += n; 514 bfd_elf_add_obj_attr_int (abfd, vendor, tag, val); 515 break; 516 default: 517 abort (); 518 } 519 } 520 break; 521 case Tag_Section: 522 case Tag_Symbol: 523 /* Don't have anywhere convenient to attach these. 524 Fall through for now. */ 525 default: 526 /* Ignore things we don't kow about. */ 527 p += subsection_len; 528 subsection_len = 0; 529 break; 530 } 531 } 532 } 533 } 534 free (contents); 535 } 536 537 /* Merge common object attributes from IBFD into OBFD. Raise an error 538 if there are conflicting attributes. Any processor-specific 539 attributes have already been merged. This must be called from the 540 bfd_elfNN_bfd_merge_private_bfd_data hook for each individual 541 target, along with any target-specific merging. Because there are 542 no common attributes other than Tag_compatibility at present, and 543 non-"gnu" Tag_compatibility is not expected in "gnu" sections, this 544 is not presently called for targets without their own 545 attributes. */ 546 547 bfd_boolean 548 _bfd_elf_merge_object_attributes (bfd *ibfd, bfd *obfd) 549 { 550 obj_attribute *in_attr; 551 obj_attribute *out_attr; 552 int vendor; 553 554 /* The only common attribute is currently Tag_compatibility, 555 accepted in both processor and "gnu" sections. */ 556 for (vendor = OBJ_ATTR_FIRST; vendor <= OBJ_ATTR_LAST; vendor++) 557 { 558 /* Handle Tag_compatibility. The tags are only compatible if the flags 559 are identical and, if the flags are '1', the strings are identical. 560 If the flags are non-zero, then we can only use the string "gnu". */ 561 in_attr = &elf_known_obj_attributes (ibfd)[vendor][Tag_compatibility]; 562 out_attr = &elf_known_obj_attributes (obfd)[vendor][Tag_compatibility]; 563 564 if (in_attr->i > 0 && strcmp (in_attr->s, "gnu") != 0) 565 { 566 _bfd_error_handler 567 (_("error: %B: Must be processed by '%s' toolchain"), 568 ibfd, in_attr->s); 569 return FALSE; 570 } 571 572 if (in_attr->i != out_attr->i 573 || (in_attr->i != 0 && strcmp (in_attr->s, out_attr->s) != 0)) 574 { 575 _bfd_error_handler (_("error: %B: Object tag '%d, %s' is " 576 "incompatible with tag '%d, %s'"), 577 ibfd, 578 in_attr->i, in_attr->s ? in_attr->s : "", 579 out_attr->i, out_attr->s ? out_attr->s : ""); 580 return FALSE; 581 } 582 } 583 584 return TRUE; 585 } 586