1 /* Low-level I/O routines for BFDs. 2 3 Copyright (C) 1990-2020 Free Software Foundation, Inc. 4 5 Written by Cygnus Support. 6 7 This file is part of BFD, the Binary File Descriptor library. 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 3 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 22 MA 02110-1301, USA. */ 23 24 #include "sysdep.h" 25 #include <limits.h> 26 #include "bfd.h" 27 #include "libbfd.h" 28 29 #ifndef S_IXUSR 30 #define S_IXUSR 0100 /* Execute by owner. */ 31 #endif 32 #ifndef S_IXGRP 33 #define S_IXGRP 0010 /* Execute by group. */ 34 #endif 35 #ifndef S_IXOTH 36 #define S_IXOTH 0001 /* Execute by others. */ 37 #endif 38 39 #ifndef FD_CLOEXEC 40 #define FD_CLOEXEC 1 41 #endif 42 43 file_ptr 44 _bfd_real_ftell (FILE *file) 45 { 46 #if defined (HAVE_FTELLO64) 47 return ftello64 (file); 48 #elif defined (HAVE_FTELLO) 49 return ftello (file); 50 #else 51 return ftell (file); 52 #endif 53 } 54 55 int 56 _bfd_real_fseek (FILE *file, file_ptr offset, int whence) 57 { 58 #if defined (HAVE_FSEEKO64) 59 return fseeko64 (file, offset, whence); 60 #elif defined (HAVE_FSEEKO) 61 return fseeko (file, offset, whence); 62 #else 63 return fseek (file, offset, whence); 64 #endif 65 } 66 67 /* Mark FILE as close-on-exec. Return FILE. FILE may be NULL, in 68 which case nothing is done. */ 69 static FILE * 70 close_on_exec (FILE *file) 71 { 72 #if defined (HAVE_FILENO) && defined (F_GETFD) 73 if (file) 74 { 75 int fd = fileno (file); 76 int old = fcntl (fd, F_GETFD, 0); 77 if (old >= 0) 78 fcntl (fd, F_SETFD, old | FD_CLOEXEC); 79 } 80 #endif 81 return file; 82 } 83 84 FILE * 85 _bfd_real_fopen (const char *filename, const char *modes) 86 { 87 #ifdef VMS 88 char *vms_attr; 89 90 /* On VMS, fopen allows file attributes as optional arguments. 91 We need to use them but we'd better to use the common prototype. 92 In fopen-vms.h, they are separated from the mode with a comma. 93 Split here. */ 94 vms_attr = strchr (modes, ','); 95 if (vms_attr == NULL) 96 { 97 /* No attributes. */ 98 return close_on_exec (fopen (filename, modes)); 99 } 100 else 101 { 102 /* Attributes found. Split. */ 103 size_t modes_len = strlen (modes) + 1; 104 char attrs[modes_len + 1]; 105 char *at[3]; 106 int i; 107 108 memcpy (attrs, modes, modes_len); 109 at[0] = attrs; 110 for (i = 0; i < 2; i++) 111 { 112 at[i + 1] = strchr (at[i], ','); 113 BFD_ASSERT (at[i + 1] != NULL); 114 *(at[i + 1]++) = 0; /* Replace ',' with a nul, and skip it. */ 115 } 116 return close_on_exec (fopen (filename, at[0], at[1], at[2])); 117 } 118 #else /* !VMS */ 119 #if defined (HAVE_FOPEN64) 120 return close_on_exec (fopen64 (filename, modes)); 121 #else 122 return close_on_exec (fopen (filename, modes)); 123 #endif 124 #endif /* !VMS */ 125 } 126 127 /* 128 INTERNAL_DEFINITION 129 struct bfd_iovec 130 131 DESCRIPTION 132 133 The <<struct bfd_iovec>> contains the internal file I/O class. 134 Each <<BFD>> has an instance of this class and all file I/O is 135 routed through it (it is assumed that the instance implements 136 all methods listed below). 137 138 .struct bfd_iovec 139 .{ 140 . {* To avoid problems with macros, a "b" rather than "f" 141 . prefix is prepended to each method name. *} 142 . {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching 143 . bytes starting at PTR. Return the number of bytes actually 144 . transfered (a read past end-of-file returns less than NBYTES), 145 . or -1 (setting <<bfd_error>>) if an error occurs. *} 146 . file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes); 147 . file_ptr (*bwrite) (struct bfd *abfd, const void *ptr, 148 . file_ptr nbytes); 149 . {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>> 150 . if an error occurs. *} 151 . file_ptr (*btell) (struct bfd *abfd); 152 . {* For the following, on successful completion a value of 0 is returned. 153 . Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *} 154 . int (*bseek) (struct bfd *abfd, file_ptr offset, int whence); 155 . int (*bclose) (struct bfd *abfd); 156 . int (*bflush) (struct bfd *abfd); 157 . int (*bstat) (struct bfd *abfd, struct stat *sb); 158 . {* Mmap a part of the files. ADDR, LEN, PROT, FLAGS and OFFSET are the usual 159 . mmap parameter, except that LEN and OFFSET do not need to be page 160 . aligned. Returns (void *)-1 on failure, mmapped address on success. 161 . Also write in MAP_ADDR the address of the page aligned buffer and in 162 . MAP_LEN the size mapped (a page multiple). Use unmap with MAP_ADDR and 163 . MAP_LEN to unmap. *} 164 . void *(*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len, 165 . int prot, int flags, file_ptr offset, 166 . void **map_addr, bfd_size_type *map_len); 167 .}; 168 169 .extern const struct bfd_iovec _bfd_memory_iovec; 170 171 */ 172 173 174 /* Return value is amount read. */ 175 176 bfd_size_type 177 bfd_bread (void *ptr, bfd_size_type size, bfd *abfd) 178 { 179 file_ptr nread; 180 bfd *element_bfd = abfd; 181 ufile_ptr offset = 0; 182 183 while (abfd->my_archive != NULL 184 && !bfd_is_thin_archive (abfd->my_archive)) 185 { 186 offset += abfd->origin; 187 abfd = abfd->my_archive; 188 } 189 190 /* If this is an archive element, don't read past the end of 191 this element. */ 192 if (element_bfd->arelt_data != NULL) 193 { 194 bfd_size_type maxbytes = arelt_size (element_bfd); 195 196 if (abfd->where < offset || abfd->where - offset >= maxbytes) 197 { 198 bfd_set_error (bfd_error_invalid_operation); 199 return -1; 200 } 201 if (abfd->where - offset + size > maxbytes) 202 size = maxbytes - (abfd->where - offset); 203 } 204 205 if (abfd->iovec == NULL) 206 { 207 bfd_set_error (bfd_error_invalid_operation); 208 return -1; 209 } 210 211 nread = abfd->iovec->bread (abfd, ptr, size); 212 if (nread != -1) 213 abfd->where += nread; 214 215 return nread; 216 } 217 218 bfd_size_type 219 bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd) 220 { 221 file_ptr nwrote; 222 223 while (abfd->my_archive != NULL 224 && !bfd_is_thin_archive (abfd->my_archive)) 225 abfd = abfd->my_archive; 226 227 if (abfd->iovec == NULL) 228 { 229 bfd_set_error (bfd_error_invalid_operation); 230 return -1; 231 } 232 233 nwrote = abfd->iovec->bwrite (abfd, ptr, size); 234 if (nwrote != -1) 235 abfd->where += nwrote; 236 if ((bfd_size_type) nwrote != size) 237 { 238 #ifdef ENOSPC 239 errno = ENOSPC; 240 #endif 241 bfd_set_error (bfd_error_system_call); 242 } 243 return nwrote; 244 } 245 246 file_ptr 247 bfd_tell (bfd *abfd) 248 { 249 ufile_ptr offset = 0; 250 file_ptr ptr; 251 252 while (abfd->my_archive != NULL 253 && !bfd_is_thin_archive (abfd->my_archive)) 254 { 255 offset += abfd->origin; 256 abfd = abfd->my_archive; 257 } 258 259 if (abfd->iovec == NULL) 260 return 0; 261 262 ptr = abfd->iovec->btell (abfd); 263 abfd->where = ptr; 264 return ptr - offset; 265 } 266 267 int 268 bfd_flush (bfd *abfd) 269 { 270 while (abfd->my_archive != NULL 271 && !bfd_is_thin_archive (abfd->my_archive)) 272 abfd = abfd->my_archive; 273 274 if (abfd->iovec == NULL) 275 return 0; 276 277 return abfd->iovec->bflush (abfd); 278 } 279 280 /* Returns 0 for success, negative value for failure (in which case 281 bfd_get_error can retrieve the error code). */ 282 int 283 bfd_stat (bfd *abfd, struct stat *statbuf) 284 { 285 int result; 286 287 while (abfd->my_archive != NULL 288 && !bfd_is_thin_archive (abfd->my_archive)) 289 abfd = abfd->my_archive; 290 291 if (abfd->iovec == NULL) 292 { 293 bfd_set_error (bfd_error_invalid_operation); 294 return -1; 295 } 296 297 result = abfd->iovec->bstat (abfd, statbuf); 298 if (result < 0) 299 bfd_set_error (bfd_error_system_call); 300 return result; 301 } 302 303 /* Returns 0 for success, nonzero for failure (in which case bfd_get_error 304 can retrieve the error code). */ 305 306 int 307 bfd_seek (bfd *abfd, file_ptr position, int direction) 308 { 309 int result; 310 ufile_ptr offset = 0; 311 312 while (abfd->my_archive != NULL 313 && !bfd_is_thin_archive (abfd->my_archive)) 314 { 315 offset += abfd->origin; 316 abfd = abfd->my_archive; 317 } 318 319 if (abfd->iovec == NULL) 320 { 321 bfd_set_error (bfd_error_invalid_operation); 322 return -1; 323 } 324 325 /* For the time being, a BFD may not seek to it's end. The problem 326 is that we don't easily have a way to recognize the end of an 327 element in an archive. */ 328 BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR); 329 330 if (direction != SEEK_CUR) 331 position += offset; 332 333 if ((direction == SEEK_CUR && position == 0) 334 || (direction == SEEK_SET && (ufile_ptr) position == abfd->where)) 335 return 0; 336 337 result = abfd->iovec->bseek (abfd, position, direction); 338 if (result != 0) 339 { 340 /* An EINVAL error probably means that the file offset was 341 absurd. */ 342 if (errno == EINVAL) 343 bfd_set_error (bfd_error_file_truncated); 344 else 345 bfd_set_error (bfd_error_system_call); 346 } 347 else 348 { 349 /* Adjust `where' field. */ 350 if (direction == SEEK_CUR) 351 abfd->where += position; 352 else 353 abfd->where = position; 354 } 355 356 return result; 357 } 358 359 /* 360 FUNCTION 361 bfd_get_mtime 362 363 SYNOPSIS 364 long bfd_get_mtime (bfd *abfd); 365 366 DESCRIPTION 367 Return the file modification time (as read from the file system, or 368 from the archive header for archive members). 369 370 */ 371 372 long 373 bfd_get_mtime (bfd *abfd) 374 { 375 struct stat buf; 376 377 if (abfd->mtime_set) 378 return abfd->mtime; 379 380 if (bfd_stat (abfd, &buf) != 0) 381 return 0; 382 383 abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */ 384 return buf.st_mtime; 385 } 386 387 /* 388 FUNCTION 389 bfd_get_size 390 391 SYNOPSIS 392 ufile_ptr bfd_get_size (bfd *abfd); 393 394 DESCRIPTION 395 Return the file size (as read from file system) for the file 396 associated with BFD @var{abfd}. 397 398 The initial motivation for, and use of, this routine is not 399 so we can get the exact size of the object the BFD applies to, since 400 that might not be generally possible (archive members for example). 401 It would be ideal if someone could eventually modify 402 it so that such results were guaranteed. 403 404 Instead, we want to ask questions like "is this NNN byte sized 405 object I'm about to try read from file offset YYY reasonable?" 406 As as example of where we might do this, some object formats 407 use string tables for which the first <<sizeof (long)>> bytes of the 408 table contain the size of the table itself, including the size bytes. 409 If an application tries to read what it thinks is one of these 410 string tables, without some way to validate the size, and for 411 some reason the size is wrong (byte swapping error, wrong location 412 for the string table, etc.), the only clue is likely to be a read 413 error when it tries to read the table, or a "virtual memory 414 exhausted" error when it tries to allocate 15 bazillon bytes 415 of space for the 15 bazillon byte table it is about to read. 416 This function at least allows us to answer the question, "is the 417 size reasonable?". 418 */ 419 420 ufile_ptr 421 bfd_get_size (bfd *abfd) 422 { 423 struct stat buf; 424 425 if (bfd_stat (abfd, &buf) != 0) 426 return 0; 427 428 return buf.st_size; 429 } 430 431 /* 432 FUNCTION 433 bfd_get_file_size 434 435 SYNOPSIS 436 ufile_ptr bfd_get_file_size (bfd *abfd); 437 438 DESCRIPTION 439 Return the file size (as read from file system) for the file 440 associated with BFD @var{abfd}. It supports both normal files 441 and archive elements. 442 443 */ 444 445 ufile_ptr 446 bfd_get_file_size (bfd *abfd) 447 { 448 if (abfd->my_archive != NULL 449 && !bfd_is_thin_archive (abfd->my_archive)) 450 return arelt_size (abfd); 451 452 return bfd_get_size (abfd); 453 } 454 455 /* 456 FUNCTION 457 bfd_mmap 458 459 SYNOPSIS 460 void *bfd_mmap (bfd *abfd, void *addr, bfd_size_type len, 461 int prot, int flags, file_ptr offset, 462 void **map_addr, bfd_size_type *map_len); 463 464 DESCRIPTION 465 Return mmap()ed region of the file, if possible and implemented. 466 LEN and OFFSET do not need to be page aligned. The page aligned 467 address and length are written to MAP_ADDR and MAP_LEN. 468 469 */ 470 471 void * 472 bfd_mmap (bfd *abfd, void *addr, bfd_size_type len, 473 int prot, int flags, file_ptr offset, 474 void **map_addr, bfd_size_type *map_len) 475 { 476 while (abfd->my_archive != NULL 477 && !bfd_is_thin_archive (abfd->my_archive)) 478 { 479 offset += abfd->origin; 480 abfd = abfd->my_archive; 481 } 482 483 if (abfd->iovec == NULL) 484 { 485 bfd_set_error (bfd_error_invalid_operation); 486 return (void *) -1; 487 } 488 489 return abfd->iovec->bmmap (abfd, addr, len, prot, flags, offset, 490 map_addr, map_len); 491 } 492 493 /* Memory file I/O operations. */ 494 495 static file_ptr 496 memory_bread (bfd *abfd, void *ptr, file_ptr size) 497 { 498 struct bfd_in_memory *bim; 499 bfd_size_type get; 500 501 bim = (struct bfd_in_memory *) abfd->iostream; 502 get = size; 503 if (abfd->where + get > bim->size) 504 { 505 if (bim->size < (bfd_size_type) abfd->where) 506 get = 0; 507 else 508 get = bim->size - abfd->where; 509 bfd_set_error (bfd_error_file_truncated); 510 } 511 memcpy (ptr, bim->buffer + abfd->where, (size_t) get); 512 return get; 513 } 514 515 static file_ptr 516 memory_bwrite (bfd *abfd, const void *ptr, file_ptr size) 517 { 518 struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream; 519 520 if (abfd->where + size > bim->size) 521 { 522 bfd_size_type newsize, oldsize; 523 524 oldsize = (bim->size + 127) & ~(bfd_size_type) 127; 525 bim->size = abfd->where + size; 526 /* Round up to cut down on memory fragmentation */ 527 newsize = (bim->size + 127) & ~(bfd_size_type) 127; 528 if (newsize > oldsize) 529 { 530 bim->buffer = (bfd_byte *) bfd_realloc_or_free (bim->buffer, newsize); 531 if (bim->buffer == NULL) 532 { 533 bim->size = 0; 534 return 0; 535 } 536 if (newsize > bim->size) 537 memset (bim->buffer + bim->size, 0, newsize - bim->size); 538 } 539 } 540 memcpy (bim->buffer + abfd->where, ptr, (size_t) size); 541 return size; 542 } 543 544 static file_ptr 545 memory_btell (bfd *abfd) 546 { 547 return abfd->where; 548 } 549 550 static int 551 memory_bseek (bfd *abfd, file_ptr position, int direction) 552 { 553 file_ptr nwhere; 554 struct bfd_in_memory *bim; 555 556 bim = (struct bfd_in_memory *) abfd->iostream; 557 558 if (direction == SEEK_SET) 559 nwhere = position; 560 else 561 nwhere = abfd->where + position; 562 563 if (nwhere < 0) 564 { 565 abfd->where = 0; 566 errno = EINVAL; 567 return -1; 568 } 569 570 if ((bfd_size_type)nwhere > bim->size) 571 { 572 if (abfd->direction == write_direction 573 || abfd->direction == both_direction) 574 { 575 bfd_size_type newsize, oldsize; 576 577 oldsize = (bim->size + 127) & ~(bfd_size_type) 127; 578 bim->size = nwhere; 579 /* Round up to cut down on memory fragmentation */ 580 newsize = (bim->size + 127) & ~(bfd_size_type) 127; 581 if (newsize > oldsize) 582 { 583 bim->buffer = (bfd_byte *) bfd_realloc_or_free (bim->buffer, newsize); 584 if (bim->buffer == NULL) 585 { 586 errno = EINVAL; 587 bim->size = 0; 588 return -1; 589 } 590 memset (bim->buffer + oldsize, 0, newsize - oldsize); 591 } 592 } 593 else 594 { 595 abfd->where = bim->size; 596 errno = EINVAL; 597 bfd_set_error (bfd_error_file_truncated); 598 return -1; 599 } 600 } 601 return 0; 602 } 603 604 static int 605 memory_bclose (struct bfd *abfd) 606 { 607 struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream; 608 609 if (bim->buffer != NULL) 610 free (bim->buffer); 611 free (bim); 612 abfd->iostream = NULL; 613 614 return 0; 615 } 616 617 static int 618 memory_bflush (bfd *abfd ATTRIBUTE_UNUSED) 619 { 620 return 0; 621 } 622 623 static int 624 memory_bstat (bfd *abfd, struct stat *statbuf) 625 { 626 struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream; 627 628 memset (statbuf, 0, sizeof (*statbuf)); 629 statbuf->st_size = bim->size; 630 631 return 0; 632 } 633 634 static void * 635 memory_bmmap (bfd *abfd ATTRIBUTE_UNUSED, void *addr ATTRIBUTE_UNUSED, 636 bfd_size_type len ATTRIBUTE_UNUSED, int prot ATTRIBUTE_UNUSED, 637 int flags ATTRIBUTE_UNUSED, file_ptr offset ATTRIBUTE_UNUSED, 638 void **map_addr ATTRIBUTE_UNUSED, 639 bfd_size_type *map_len ATTRIBUTE_UNUSED) 640 { 641 return (void *)-1; 642 } 643 644 const struct bfd_iovec _bfd_memory_iovec = 645 { 646 &memory_bread, &memory_bwrite, &memory_btell, &memory_bseek, 647 &memory_bclose, &memory_bflush, &memory_bstat, &memory_bmmap 648 }; 649