| 1 | /* BFD back-end for WebAssembly modules. |
| 2 | Copyright (C) 2017-2020 Free Software Foundation, Inc. |
| 3 | |
| 4 | Based on srec.c, mmo.c, and binary.c |
| 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 | /* The WebAssembly module format is a simple object file format |
| 24 | including up to 11 numbered sections, plus any number of named |
| 25 | "custom" sections. It is described at: |
| 26 | https://github.com/WebAssembly/design/blob/master/BinaryEncoding.md. */ |
| 27 | |
| 28 | #include "sysdep.h" |
| 29 | #include "alloca-conf.h" |
| 30 | #include "bfd.h" |
| 31 | #include <limits.h> |
| 32 | #include "libiberty.h" |
| 33 | #include "libbfd.h" |
| 34 | #include "wasm-module.h" |
| 35 | |
| 36 | typedef struct |
| 37 | { |
| 38 | asymbol * symbols; |
| 39 | bfd_size_type symcount; |
| 40 | } tdata_type; |
| 41 | |
| 42 | static const char * const wasm_numbered_sections[] = |
| 43 | { |
| 44 | NULL, /* Custom section, different layout. */ |
| 45 | WASM_SECTION ( 1, "type"), |
| 46 | WASM_SECTION ( 2, "import"), |
| 47 | WASM_SECTION ( 3, "function"), |
| 48 | WASM_SECTION ( 4, "table"), |
| 49 | WASM_SECTION ( 5, "memory"), |
| 50 | WASM_SECTION ( 6, "global"), |
| 51 | WASM_SECTION ( 7, "export"), |
| 52 | WASM_SECTION ( 8, "start"), |
| 53 | WASM_SECTION ( 9, "element"), |
| 54 | WASM_SECTION (10, "code"), |
| 55 | WASM_SECTION (11, "data"), |
| 56 | }; |
| 57 | |
| 58 | #define WASM_NUMBERED_SECTIONS ARRAY_SIZE (wasm_numbered_sections) |
| 59 | |
| 60 | /* Resolve SECTION_CODE to a section name if there is one, NULL |
| 61 | otherwise. */ |
| 62 | |
| 63 | static const char * |
| 64 | wasm_section_code_to_name (bfd_byte section_code) |
| 65 | { |
| 66 | if (section_code < WASM_NUMBERED_SECTIONS) |
| 67 | return wasm_numbered_sections[section_code]; |
| 68 | |
| 69 | return NULL; |
| 70 | } |
| 71 | |
| 72 | /* Translate section name NAME to a section code, or 0 if it's a |
| 73 | custom name. */ |
| 74 | |
| 75 | static unsigned int |
| 76 | wasm_section_name_to_code (const char *name) |
| 77 | { |
| 78 | unsigned i; |
| 79 | |
| 80 | for (i = 1; i < WASM_NUMBERED_SECTIONS; i++) |
| 81 | if (strcmp (name, wasm_numbered_sections[i]) == 0) |
| 82 | return i; |
| 83 | |
| 84 | return 0; |
| 85 | } |
| 86 | |
| 87 | /* WebAssembly LEB128 integers are sufficiently like DWARF LEB128 |
| 88 | integers that we use _bfd_safe_read_leb128, but there are two |
| 89 | points of difference: |
| 90 | |
| 91 | - WebAssembly requires a 32-bit value to be encoded in at most 5 |
| 92 | bytes, etc. |
| 93 | - _bfd_safe_read_leb128 accepts incomplete LEB128 encodings at the |
| 94 | end of the buffer, while these are invalid in WebAssembly. |
| 95 | |
| 96 | Those differences mean that we will accept some files that are |
| 97 | invalid WebAssembly. */ |
| 98 | |
| 99 | /* Read an LEB128-encoded integer from ABFD's I/O stream, reading one |
| 100 | byte at a time. Set ERROR_RETURN if no complete integer could be |
| 101 | read, LENGTH_RETURN to the number of bytes read (including bytes in |
| 102 | incomplete numbers). SIGN means interpret the number as SLEB128. */ |
| 103 | |
| 104 | static bfd_vma |
| 105 | wasm_read_leb128 (bfd * abfd, |
| 106 | bfd_boolean * error_return, |
| 107 | unsigned int * length_return, |
| 108 | bfd_boolean sign) |
| 109 | { |
| 110 | bfd_vma result = 0; |
| 111 | unsigned int num_read = 0; |
| 112 | unsigned int shift = 0; |
| 113 | unsigned char byte = 0; |
| 114 | int status = 1; |
| 115 | |
| 116 | while (bfd_bread (&byte, 1, abfd) == 1) |
| 117 | { |
| 118 | num_read++; |
| 119 | |
| 120 | if (shift < sizeof (result) * 8) |
| 121 | { |
| 122 | result |= ((bfd_vma) (byte & 0x7f)) << shift; |
| 123 | if ((result >> shift) != (byte & 0x7f)) |
| 124 | /* Overflow. */ |
| 125 | status |= 2; |
| 126 | shift += 7; |
| 127 | } |
| 128 | else if ((byte & 0x7f) != 0) |
| 129 | status |= 2; |
| 130 | |
| 131 | if ((byte & 0x80) == 0) |
| 132 | { |
| 133 | status &= ~1; |
| 134 | if (sign && (shift < 8 * sizeof (result)) && (byte & 0x40)) |
| 135 | result |= -((bfd_vma) 1 << shift); |
| 136 | break; |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | if (length_return != NULL) |
| 141 | *length_return = num_read; |
| 142 | if (error_return != NULL) |
| 143 | *error_return = status != 0; |
| 144 | |
| 145 | return result; |
| 146 | } |
| 147 | |
| 148 | /* Encode an integer V as LEB128 and write it to ABFD, return TRUE on |
| 149 | success. */ |
| 150 | |
| 151 | static bfd_boolean |
| 152 | wasm_write_uleb128 (bfd *abfd, bfd_vma v) |
| 153 | { |
| 154 | do |
| 155 | { |
| 156 | bfd_byte c = v & 0x7f; |
| 157 | v >>= 7; |
| 158 | |
| 159 | if (v) |
| 160 | c |= 0x80; |
| 161 | |
| 162 | if (bfd_bwrite (&c, 1, abfd) != 1) |
| 163 | return FALSE; |
| 164 | } |
| 165 | while (v); |
| 166 | |
| 167 | return TRUE; |
| 168 | } |
| 169 | |
| 170 | /* Read the LEB128 integer at P, saving it to X; at end of buffer, |
| 171 | jump to error_return. */ |
| 172 | #define READ_LEB128(x, p, end) \ |
| 173 | do \ |
| 174 | { \ |
| 175 | unsigned int length_read; \ |
| 176 | (x) = _bfd_safe_read_leb128 (abfd, (p), &length_read, \ |
| 177 | FALSE, (end)); \ |
| 178 | (p) += length_read; \ |
| 179 | if (length_read == 0) \ |
| 180 | goto error_return; \ |
| 181 | } \ |
| 182 | while (0) |
| 183 | |
| 184 | /* Verify the magic number at the beginning of a WebAssembly module |
| 185 | ABFD, setting ERRORPTR if there's a mismatch. */ |
| 186 | |
| 187 | static bfd_boolean |
| 188 | wasm_read_magic (bfd *abfd, bfd_boolean *errorptr) |
| 189 | { |
| 190 | bfd_byte magic_const[SIZEOF_WASM_MAGIC] = WASM_MAGIC; |
| 191 | bfd_byte magic[SIZEOF_WASM_MAGIC]; |
| 192 | |
| 193 | if (bfd_bread (magic, sizeof (magic), abfd) == sizeof (magic) |
| 194 | && memcmp (magic, magic_const, sizeof (magic)) == 0) |
| 195 | return TRUE; |
| 196 | |
| 197 | *errorptr = TRUE; |
| 198 | return FALSE; |
| 199 | } |
| 200 | |
| 201 | /* Read the version number from ABFD, returning TRUE if it's a supported |
| 202 | version. Set ERRORPTR otherwise. */ |
| 203 | |
| 204 | static bfd_boolean |
| 205 | wasm_read_version (bfd *abfd, bfd_boolean *errorptr) |
| 206 | { |
| 207 | bfd_byte vers_const[SIZEOF_WASM_VERSION] = WASM_VERSION; |
| 208 | bfd_byte vers[SIZEOF_WASM_VERSION]; |
| 209 | |
| 210 | if (bfd_bread (vers, sizeof (vers), abfd) == sizeof (vers) |
| 211 | /* Don't attempt to parse newer versions, which are likely to |
| 212 | require code changes. */ |
| 213 | && memcmp (vers, vers_const, sizeof (vers)) == 0) |
| 214 | return TRUE; |
| 215 | |
| 216 | *errorptr = TRUE; |
| 217 | return FALSE; |
| 218 | } |
| 219 | |
| 220 | /* Read the WebAssembly header (magic number plus version number) from |
| 221 | ABFD, setting ERRORPTR to TRUE if there is a mismatch. */ |
| 222 | |
| 223 | static bfd_boolean |
| 224 | wasm_read_header (bfd *abfd, bfd_boolean *errorptr) |
| 225 | { |
| 226 | if (! wasm_read_magic (abfd, errorptr)) |
| 227 | return FALSE; |
| 228 | |
| 229 | if (! wasm_read_version (abfd, errorptr)) |
| 230 | return FALSE; |
| 231 | |
| 232 | return TRUE; |
| 233 | } |
| 234 | |
| 235 | /* Scan the "function" subsection of the "name" section ASECT in the |
| 236 | wasm module ABFD. Create symbols. Return TRUE on success. */ |
| 237 | |
| 238 | static bfd_boolean |
| 239 | wasm_scan_name_function_section (bfd *abfd, sec_ptr asect) |
| 240 | { |
| 241 | bfd_byte *p; |
| 242 | bfd_byte *end; |
| 243 | bfd_vma payload_size; |
| 244 | bfd_vma symcount = 0; |
| 245 | tdata_type *tdata = abfd->tdata.any; |
| 246 | asymbol *symbols = NULL; |
| 247 | sec_ptr space_function_index; |
| 248 | size_t amt; |
| 249 | |
| 250 | p = asect->contents; |
| 251 | end = asect->contents + asect->size; |
| 252 | |
| 253 | if (!p) |
| 254 | return FALSE; |
| 255 | |
| 256 | while (p < end) |
| 257 | { |
| 258 | bfd_byte subsection_code = *p++; |
| 259 | if (subsection_code == WASM_FUNCTION_SUBSECTION) |
| 260 | break; |
| 261 | |
| 262 | /* subsection_code is documented to be a varuint7, meaning that |
| 263 | it has to be a single byte in the 0 - 127 range. If it isn't, |
| 264 | the spec must have changed underneath us, so give up. */ |
| 265 | if (subsection_code & 0x80) |
| 266 | return FALSE; |
| 267 | |
| 268 | READ_LEB128 (payload_size, p, end); |
| 269 | |
| 270 | if (payload_size > (size_t) (end - p)) |
| 271 | return FALSE; |
| 272 | |
| 273 | p += payload_size; |
| 274 | } |
| 275 | |
| 276 | if (p >= end) |
| 277 | return FALSE; |
| 278 | |
| 279 | READ_LEB128 (payload_size, p, end); |
| 280 | |
| 281 | if (payload_size > (size_t) (end - p)) |
| 282 | return FALSE; |
| 283 | |
| 284 | end = p + payload_size; |
| 285 | |
| 286 | READ_LEB128 (symcount, p, end); |
| 287 | |
| 288 | /* Sanity check: each symbol has at least two bytes. */ |
| 289 | if (symcount > payload_size / 2) |
| 290 | return FALSE; |
| 291 | |
| 292 | tdata->symcount = symcount; |
| 293 | |
| 294 | space_function_index |
| 295 | = bfd_make_section_with_flags (abfd, WASM_SECTION_FUNCTION_INDEX, |
| 296 | SEC_READONLY | SEC_CODE); |
| 297 | |
| 298 | if (!space_function_index) |
| 299 | space_function_index |
| 300 | = bfd_get_section_by_name (abfd, WASM_SECTION_FUNCTION_INDEX); |
| 301 | |
| 302 | if (!space_function_index) |
| 303 | return FALSE; |
| 304 | |
| 305 | if (_bfd_mul_overflow (tdata->symcount, sizeof (asymbol), &amt)) |
| 306 | { |
| 307 | bfd_set_error (bfd_error_file_too_big); |
| 308 | return FALSE; |
| 309 | } |
| 310 | symbols = bfd_alloc (abfd, amt); |
| 311 | if (!symbols) |
| 312 | return FALSE; |
| 313 | |
| 314 | for (symcount = 0; p < end && symcount < tdata->symcount; symcount++) |
| 315 | { |
| 316 | bfd_vma idx; |
| 317 | bfd_vma len; |
| 318 | char *name; |
| 319 | asymbol *sym; |
| 320 | |
| 321 | READ_LEB128 (idx, p, end); |
| 322 | READ_LEB128 (len, p, end); |
| 323 | |
| 324 | if (len > (size_t) (end - p)) |
| 325 | goto error_return; |
| 326 | |
| 327 | name = bfd_alloc (abfd, len + 1); |
| 328 | if (!name) |
| 329 | goto error_return; |
| 330 | |
| 331 | memcpy (name, p, len); |
| 332 | name[len] = 0; |
| 333 | p += len; |
| 334 | |
| 335 | sym = &symbols[symcount]; |
| 336 | sym->the_bfd = abfd; |
| 337 | sym->name = name; |
| 338 | sym->value = idx; |
| 339 | sym->flags = BSF_GLOBAL | BSF_FUNCTION; |
| 340 | sym->section = space_function_index; |
| 341 | sym->udata.p = NULL; |
| 342 | } |
| 343 | |
| 344 | if (symcount < tdata->symcount) |
| 345 | goto error_return; |
| 346 | |
| 347 | tdata->symbols = symbols; |
| 348 | abfd->symcount = symcount; |
| 349 | |
| 350 | return TRUE; |
| 351 | |
| 352 | error_return: |
| 353 | bfd_release (abfd, symbols); |
| 354 | return FALSE; |
| 355 | } |
| 356 | |
| 357 | /* Read a byte from ABFD and return it, or EOF for EOF or error. |
| 358 | Set ERRORPTR on non-EOF error. */ |
| 359 | |
| 360 | static int |
| 361 | wasm_read_byte (bfd *abfd, bfd_boolean *errorptr) |
| 362 | { |
| 363 | bfd_byte byte; |
| 364 | |
| 365 | if (bfd_bread (&byte, (bfd_size_type) 1, abfd) != 1) |
| 366 | { |
| 367 | if (bfd_get_error () != bfd_error_file_truncated) |
| 368 | *errorptr = TRUE; |
| 369 | return EOF; |
| 370 | } |
| 371 | |
| 372 | return byte; |
| 373 | } |
| 374 | |
| 375 | /* Scan the wasm module ABFD, creating sections and symbols. |
| 376 | Return TRUE on success. */ |
| 377 | |
| 378 | static bfd_boolean |
| 379 | wasm_scan (bfd *abfd) |
| 380 | { |
| 381 | bfd_boolean error = FALSE; |
| 382 | /* Fake VMAs for now. Choose 0x80000000 as base to avoid clashes |
| 383 | with actual data addresses. */ |
| 384 | bfd_vma vma = 0x80000000; |
| 385 | int section_code; |
| 386 | unsigned int bytes_read; |
| 387 | asection *bfdsec; |
| 388 | |
| 389 | if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0) |
| 390 | goto error_return; |
| 391 | |
| 392 | if (!wasm_read_header (abfd, &error)) |
| 393 | goto error_return; |
| 394 | |
| 395 | while ((section_code = wasm_read_byte (abfd, &error)) != EOF) |
| 396 | { |
| 397 | if (section_code != 0) |
| 398 | { |
| 399 | const char *sname = wasm_section_code_to_name (section_code); |
| 400 | |
| 401 | if (!sname) |
| 402 | goto error_return; |
| 403 | |
| 404 | bfdsec = bfd_make_section_anyway_with_flags (abfd, sname, |
| 405 | SEC_HAS_CONTENTS); |
| 406 | if (bfdsec == NULL) |
| 407 | goto error_return; |
| 408 | |
| 409 | bfdsec->vma = vma; |
| 410 | bfdsec->lma = vma; |
| 411 | bfdsec->size = wasm_read_leb128 (abfd, &error, &bytes_read, FALSE); |
| 412 | if (error) |
| 413 | goto error_return; |
| 414 | bfdsec->filepos = bfd_tell (abfd); |
| 415 | bfdsec->alignment_power = 0; |
| 416 | } |
| 417 | else |
| 418 | { |
| 419 | bfd_vma payload_len; |
| 420 | file_ptr section_start; |
| 421 | bfd_vma namelen; |
| 422 | char *name; |
| 423 | char *prefix = WASM_SECTION_PREFIX; |
| 424 | size_t prefixlen = strlen (prefix); |
| 425 | |
| 426 | payload_len = wasm_read_leb128 (abfd, &error, &bytes_read, FALSE); |
| 427 | if (error) |
| 428 | goto error_return; |
| 429 | section_start = bfd_tell (abfd); |
| 430 | namelen = wasm_read_leb128 (abfd, &error, &bytes_read, FALSE); |
| 431 | if (error || namelen > payload_len) |
| 432 | goto error_return; |
| 433 | name = bfd_alloc (abfd, namelen + prefixlen + 1); |
| 434 | if (!name) |
| 435 | goto error_return; |
| 436 | memcpy (name, prefix, prefixlen); |
| 437 | if (bfd_bread (name + prefixlen, namelen, abfd) != namelen) |
| 438 | goto error_return; |
| 439 | name[prefixlen + namelen] = 0; |
| 440 | |
| 441 | bfdsec = bfd_make_section_anyway_with_flags (abfd, name, |
| 442 | SEC_HAS_CONTENTS); |
| 443 | if (bfdsec == NULL) |
| 444 | goto error_return; |
| 445 | |
| 446 | bfdsec->vma = vma; |
| 447 | bfdsec->lma = vma; |
| 448 | bfdsec->filepos = bfd_tell (abfd); |
| 449 | bfdsec->size = section_start + payload_len - bfdsec->filepos; |
| 450 | bfdsec->alignment_power = 0; |
| 451 | } |
| 452 | |
| 453 | if (bfdsec->size != 0) |
| 454 | { |
| 455 | bfdsec->contents = _bfd_alloc_and_read (abfd, bfdsec->size, |
| 456 | bfdsec->size); |
| 457 | if (!bfdsec->contents) |
| 458 | goto error_return; |
| 459 | } |
| 460 | |
| 461 | vma += bfdsec->size; |
| 462 | } |
| 463 | |
| 464 | /* Make sure we're at actual EOF. There's no indication in the |
| 465 | WebAssembly format of how long the file is supposed to be. */ |
| 466 | if (error) |
| 467 | goto error_return; |
| 468 | |
| 469 | return TRUE; |
| 470 | |
| 471 | error_return: |
| 472 | return FALSE; |
| 473 | } |
| 474 | |
| 475 | /* Put a numbered section ASECT of ABFD into the table of numbered |
| 476 | sections pointed to by FSARG. */ |
| 477 | |
| 478 | static void |
| 479 | wasm_register_section (bfd *abfd ATTRIBUTE_UNUSED, |
| 480 | asection *asect, |
| 481 | void *fsarg) |
| 482 | { |
| 483 | sec_ptr *numbered_sections = fsarg; |
| 484 | int idx = wasm_section_name_to_code (asect->name); |
| 485 | |
| 486 | if (idx == 0) |
| 487 | return; |
| 488 | |
| 489 | numbered_sections[idx] = asect; |
| 490 | } |
| 491 | |
| 492 | struct compute_section_arg |
| 493 | { |
| 494 | bfd_vma pos; |
| 495 | bfd_boolean failed; |
| 496 | }; |
| 497 | |
| 498 | /* Compute the file position of ABFD's section ASECT. FSARG is a |
| 499 | pointer to the current file position. |
| 500 | |
| 501 | We allow section names of the form .wasm.id to encode the numbered |
| 502 | section with ID id, if it exists; otherwise, a custom section with |
| 503 | ID "id" is produced. Arbitrary section names are for sections that |
| 504 | are assumed already to contain a section header; those are appended |
| 505 | to the WebAssembly module verbatim. */ |
| 506 | |
| 507 | static void |
| 508 | wasm_compute_custom_section_file_position (bfd *abfd, |
| 509 | sec_ptr asect, |
| 510 | void *fsarg) |
| 511 | { |
| 512 | struct compute_section_arg *fs = fsarg; |
| 513 | int idx; |
| 514 | |
| 515 | if (fs->failed) |
| 516 | return; |
| 517 | |
| 518 | idx = wasm_section_name_to_code (asect->name); |
| 519 | |
| 520 | if (idx != 0) |
| 521 | return; |
| 522 | |
| 523 | if (CONST_STRNEQ (asect->name, WASM_SECTION_PREFIX)) |
| 524 | { |
| 525 | const char *name = asect->name + strlen (WASM_SECTION_PREFIX); |
| 526 | bfd_size_type payload_len = asect->size; |
| 527 | bfd_size_type name_len = strlen (name); |
| 528 | bfd_size_type nl = name_len; |
| 529 | |
| 530 | payload_len += name_len; |
| 531 | |
| 532 | do |
| 533 | { |
| 534 | payload_len++; |
| 535 | nl >>= 7; |
| 536 | } |
| 537 | while (nl); |
| 538 | |
| 539 | bfd_seek (abfd, fs->pos, SEEK_SET); |
| 540 | if (! wasm_write_uleb128 (abfd, 0) |
| 541 | || ! wasm_write_uleb128 (abfd, payload_len) |
| 542 | || ! wasm_write_uleb128 (abfd, name_len) |
| 543 | || bfd_bwrite (name, name_len, abfd) != name_len) |
| 544 | goto error_return; |
| 545 | fs->pos = asect->filepos = bfd_tell (abfd); |
| 546 | } |
| 547 | else |
| 548 | { |
| 549 | asect->filepos = fs->pos; |
| 550 | } |
| 551 | |
| 552 | |
| 553 | fs->pos += asect->size; |
| 554 | return; |
| 555 | |
| 556 | error_return: |
| 557 | fs->failed = TRUE; |
| 558 | } |
| 559 | |
| 560 | /* Compute the file positions for the sections of ABFD. Currently, |
| 561 | this writes all numbered sections first, in order, then all custom |
| 562 | sections, in section order. |
| 563 | |
| 564 | The spec says that the numbered sections must appear in order of |
| 565 | their ids, but custom sections can appear in any position and any |
| 566 | order, and more than once. FIXME: support that. */ |
| 567 | |
| 568 | static bfd_boolean |
| 569 | wasm_compute_section_file_positions (bfd *abfd) |
| 570 | { |
| 571 | bfd_byte magic[SIZEOF_WASM_MAGIC] = WASM_MAGIC; |
| 572 | bfd_byte vers[SIZEOF_WASM_VERSION] = WASM_VERSION; |
| 573 | sec_ptr numbered_sections[WASM_NUMBERED_SECTIONS]; |
| 574 | struct compute_section_arg fs; |
| 575 | unsigned int i; |
| 576 | |
| 577 | bfd_seek (abfd, (bfd_vma) 0, SEEK_SET); |
| 578 | |
| 579 | if (bfd_bwrite (magic, sizeof (magic), abfd) != (sizeof magic) |
| 580 | || bfd_bwrite (vers, sizeof (vers), abfd) != sizeof (vers)) |
| 581 | return FALSE; |
| 582 | |
| 583 | for (i = 0; i < WASM_NUMBERED_SECTIONS; i++) |
| 584 | numbered_sections[i] = NULL; |
| 585 | |
| 586 | bfd_map_over_sections (abfd, wasm_register_section, numbered_sections); |
| 587 | |
| 588 | fs.pos = bfd_tell (abfd); |
| 589 | for (i = 0; i < WASM_NUMBERED_SECTIONS; i++) |
| 590 | { |
| 591 | sec_ptr sec = numbered_sections[i]; |
| 592 | bfd_size_type size; |
| 593 | |
| 594 | if (! sec) |
| 595 | continue; |
| 596 | size = sec->size; |
| 597 | if (bfd_seek (abfd, fs.pos, SEEK_SET) != 0) |
| 598 | return FALSE; |
| 599 | if (! wasm_write_uleb128 (abfd, i) |
| 600 | || ! wasm_write_uleb128 (abfd, size)) |
| 601 | return FALSE; |
| 602 | fs.pos = sec->filepos = bfd_tell (abfd); |
| 603 | fs.pos += size; |
| 604 | } |
| 605 | |
| 606 | fs.failed = FALSE; |
| 607 | |
| 608 | bfd_map_over_sections (abfd, wasm_compute_custom_section_file_position, &fs); |
| 609 | |
| 610 | if (fs.failed) |
| 611 | return FALSE; |
| 612 | |
| 613 | abfd->output_has_begun = TRUE; |
| 614 | |
| 615 | return TRUE; |
| 616 | } |
| 617 | |
| 618 | static bfd_boolean |
| 619 | wasm_set_section_contents (bfd *abfd, |
| 620 | sec_ptr section, |
| 621 | const void *location, |
| 622 | file_ptr offset, |
| 623 | bfd_size_type count) |
| 624 | { |
| 625 | if (count == 0) |
| 626 | return TRUE; |
| 627 | |
| 628 | if (! abfd->output_has_begun |
| 629 | && ! wasm_compute_section_file_positions (abfd)) |
| 630 | return FALSE; |
| 631 | |
| 632 | if (bfd_seek (abfd, section->filepos + offset, SEEK_SET) != 0 |
| 633 | || bfd_bwrite (location, count, abfd) != count) |
| 634 | return FALSE; |
| 635 | |
| 636 | return TRUE; |
| 637 | } |
| 638 | |
| 639 | static bfd_boolean |
| 640 | wasm_write_object_contents (bfd* abfd) |
| 641 | { |
| 642 | bfd_byte magic[] = WASM_MAGIC; |
| 643 | bfd_byte vers[] = WASM_VERSION; |
| 644 | |
| 645 | if (bfd_seek (abfd, 0, SEEK_SET) != 0) |
| 646 | return FALSE; |
| 647 | |
| 648 | if (bfd_bwrite (magic, sizeof (magic), abfd) != sizeof (magic) |
| 649 | || bfd_bwrite (vers, sizeof (vers), abfd) != sizeof (vers)) |
| 650 | return FALSE; |
| 651 | |
| 652 | return TRUE; |
| 653 | } |
| 654 | |
| 655 | static bfd_boolean |
| 656 | wasm_mkobject (bfd *abfd) |
| 657 | { |
| 658 | tdata_type *tdata = (tdata_type *) bfd_alloc (abfd, sizeof (tdata_type)); |
| 659 | |
| 660 | if (! tdata) |
| 661 | return FALSE; |
| 662 | |
| 663 | tdata->symbols = NULL; |
| 664 | tdata->symcount = 0; |
| 665 | |
| 666 | abfd->tdata.any = tdata; |
| 667 | |
| 668 | return TRUE; |
| 669 | } |
| 670 | |
| 671 | static long |
| 672 | wasm_get_symtab_upper_bound (bfd *abfd) |
| 673 | { |
| 674 | tdata_type *tdata = abfd->tdata.any; |
| 675 | |
| 676 | return (tdata->symcount + 1) * (sizeof (asymbol *)); |
| 677 | } |
| 678 | |
| 679 | static long |
| 680 | wasm_canonicalize_symtab (bfd *abfd, asymbol **alocation) |
| 681 | { |
| 682 | tdata_type *tdata = abfd->tdata.any; |
| 683 | size_t i; |
| 684 | |
| 685 | for (i = 0; i < tdata->symcount; i++) |
| 686 | alocation[i] = &tdata->symbols[i]; |
| 687 | alocation[i] = NULL; |
| 688 | |
| 689 | return tdata->symcount; |
| 690 | } |
| 691 | |
| 692 | static asymbol * |
| 693 | wasm_make_empty_symbol (bfd *abfd) |
| 694 | { |
| 695 | size_t amt = sizeof (asymbol); |
| 696 | asymbol *new_symbol = (asymbol *) bfd_zalloc (abfd, amt); |
| 697 | |
| 698 | if (! new_symbol) |
| 699 | return NULL; |
| 700 | new_symbol->the_bfd = abfd; |
| 701 | return new_symbol; |
| 702 | } |
| 703 | |
| 704 | static void |
| 705 | wasm_print_symbol (bfd *abfd, |
| 706 | void * filep, |
| 707 | asymbol *symbol, |
| 708 | bfd_print_symbol_type how) |
| 709 | { |
| 710 | FILE *file = (FILE *) filep; |
| 711 | |
| 712 | switch (how) |
| 713 | { |
| 714 | case bfd_print_symbol_name: |
| 715 | fprintf (file, "%s", symbol->name); |
| 716 | break; |
| 717 | |
| 718 | default: |
| 719 | bfd_print_symbol_vandf (abfd, filep, symbol); |
| 720 | fprintf (file, " %-5s %s", symbol->section->name, symbol->name); |
| 721 | } |
| 722 | } |
| 723 | |
| 724 | static void |
| 725 | wasm_get_symbol_info (bfd *abfd ATTRIBUTE_UNUSED, |
| 726 | asymbol *symbol, |
| 727 | symbol_info *ret) |
| 728 | { |
| 729 | bfd_symbol_info (symbol, ret); |
| 730 | } |
| 731 | |
| 732 | /* Check whether ABFD is a WebAssembly module; if so, scan it. */ |
| 733 | |
| 734 | static bfd_cleanup |
| 735 | wasm_object_p (bfd *abfd) |
| 736 | { |
| 737 | bfd_boolean error; |
| 738 | asection *s; |
| 739 | |
| 740 | if (bfd_seek (abfd, (file_ptr) 0, SEEK_SET) != 0) |
| 741 | return NULL; |
| 742 | |
| 743 | if (!wasm_read_header (abfd, &error)) |
| 744 | { |
| 745 | bfd_set_error (bfd_error_wrong_format); |
| 746 | return NULL; |
| 747 | } |
| 748 | |
| 749 | if (!wasm_mkobject (abfd)) |
| 750 | return NULL; |
| 751 | |
| 752 | if (!wasm_scan (abfd) |
| 753 | || !bfd_default_set_arch_mach (abfd, bfd_arch_wasm32, 0)) |
| 754 | { |
| 755 | bfd_release (abfd, abfd->tdata.any); |
| 756 | abfd->tdata.any = NULL; |
| 757 | return NULL; |
| 758 | } |
| 759 | |
| 760 | s = bfd_get_section_by_name (abfd, WASM_NAME_SECTION); |
| 761 | if (s != NULL && wasm_scan_name_function_section (abfd, s)) |
| 762 | abfd->flags |= HAS_SYMS; |
| 763 | |
| 764 | return _bfd_no_cleanup; |
| 765 | } |
| 766 | |
| 767 | /* BFD_JUMP_TABLE_WRITE */ |
| 768 | #define wasm_set_arch_mach _bfd_generic_set_arch_mach |
| 769 | |
| 770 | /* BFD_JUMP_TABLE_SYMBOLS */ |
| 771 | #define wasm_get_symbol_version_string _bfd_nosymbols_get_symbol_version_string |
| 772 | #define wasm_bfd_is_local_label_name bfd_generic_is_local_label_name |
| 773 | #define wasm_bfd_is_target_special_symbol _bfd_bool_bfd_asymbol_false |
| 774 | #define wasm_get_lineno _bfd_nosymbols_get_lineno |
| 775 | #define wasm_find_nearest_line _bfd_nosymbols_find_nearest_line |
| 776 | #define wasm_find_line _bfd_nosymbols_find_line |
| 777 | #define wasm_find_inliner_info _bfd_nosymbols_find_inliner_info |
| 778 | #define wasm_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol |
| 779 | #define wasm_read_minisymbols _bfd_generic_read_minisymbols |
| 780 | #define wasm_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol |
| 781 | |
| 782 | const bfd_target wasm_vec = |
| 783 | { |
| 784 | "wasm", /* Name. */ |
| 785 | bfd_target_unknown_flavour, |
| 786 | BFD_ENDIAN_LITTLE, |
| 787 | BFD_ENDIAN_LITTLE, |
| 788 | (HAS_SYMS | WP_TEXT), /* Object flags. */ |
| 789 | (SEC_CODE | SEC_DATA | SEC_HAS_CONTENTS), /* Section flags. */ |
| 790 | 0, /* Leading underscore. */ |
| 791 | ' ', /* AR_pad_char. */ |
| 792 | 255, /* AR_max_namelen. */ |
| 793 | 0, /* Match priority. */ |
| 794 | /* Routines to byte-swap various sized integers from the data sections. */ |
| 795 | bfd_getl64, bfd_getl_signed_64, bfd_putl64, |
| 796 | bfd_getl32, bfd_getl_signed_32, bfd_putl32, |
| 797 | bfd_getl16, bfd_getl_signed_16, bfd_putl16, |
| 798 | |
| 799 | /* Routines to byte-swap various sized integers from the file headers. */ |
| 800 | bfd_getl64, bfd_getl_signed_64, bfd_putl64, |
| 801 | bfd_getl32, bfd_getl_signed_32, bfd_putl32, |
| 802 | bfd_getl16, bfd_getl_signed_16, bfd_putl16, |
| 803 | |
| 804 | { |
| 805 | _bfd_dummy_target, |
| 806 | wasm_object_p, /* bfd_check_format. */ |
| 807 | _bfd_dummy_target, |
| 808 | _bfd_dummy_target, |
| 809 | }, |
| 810 | { |
| 811 | _bfd_bool_bfd_false_error, |
| 812 | wasm_mkobject, |
| 813 | _bfd_generic_mkarchive, |
| 814 | _bfd_bool_bfd_false_error, |
| 815 | }, |
| 816 | { /* bfd_write_contents. */ |
| 817 | _bfd_bool_bfd_false_error, |
| 818 | wasm_write_object_contents, |
| 819 | _bfd_write_archive_contents, |
| 820 | _bfd_bool_bfd_false_error, |
| 821 | }, |
| 822 | |
| 823 | BFD_JUMP_TABLE_GENERIC (_bfd_generic), |
| 824 | BFD_JUMP_TABLE_COPY (_bfd_generic), |
| 825 | BFD_JUMP_TABLE_CORE (_bfd_nocore), |
| 826 | BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive), |
| 827 | BFD_JUMP_TABLE_SYMBOLS (wasm), |
| 828 | BFD_JUMP_TABLE_RELOCS (_bfd_norelocs), |
| 829 | BFD_JUMP_TABLE_WRITE (wasm), |
| 830 | BFD_JUMP_TABLE_LINK (_bfd_nolink), |
| 831 | BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic), |
| 832 | |
| 833 | NULL, |
| 834 | |
| 835 | NULL, |
| 836 | }; |