1 /* Low-level I/O routines for BFDs. 2 3 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 4 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 5 Free Software Foundation, Inc. 6 7 Written by Cygnus Support. 8 9 This file is part of BFD, the Binary File Descriptor library. 10 11 This program is free software; you can redistribute it and/or modify 12 it under the terms of the GNU General Public License as published by 13 the Free Software Foundation; either version 3 of the License, or 14 (at your option) any later version. 15 16 This program is distributed in the hope that it will be useful, 17 but WITHOUT ANY WARRANTY; without even the implied warranty of 18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19 GNU General Public License for more details. 20 21 You should have received a copy of the GNU General Public License 22 along with this program; if not, write to the Free Software 23 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 24 MA 02110-1301, USA. */ 25 26 #include "sysdep.h" 27 #include <limits.h> 28 #include "bfd.h" 29 #include "libbfd.h" 30 31 #ifndef S_IXUSR 32 #define S_IXUSR 0100 /* Execute by owner. */ 33 #endif 34 #ifndef S_IXGRP 35 #define S_IXGRP 0010 /* Execute by group. */ 36 #endif 37 #ifndef S_IXOTH 38 #define S_IXOTH 0001 /* Execute by others. */ 39 #endif 40 41 #ifndef FD_CLOEXEC 42 #define FD_CLOEXEC 1 43 #endif 44 45 file_ptr 46 real_ftell (FILE *file) 47 { 48 #if defined (HAVE_FTELLO64) 49 return ftello64 (file); 50 #elif defined (HAVE_FTELLO) 51 return ftello (file); 52 #else 53 return ftell (file); 54 #endif 55 } 56 57 int 58 real_fseek (FILE *file, file_ptr offset, int whence) 59 { 60 #if defined (HAVE_FSEEKO64) 61 return fseeko64 (file, offset, whence); 62 #elif defined (HAVE_FSEEKO) 63 return fseeko (file, offset, whence); 64 #else 65 return fseek (file, offset, whence); 66 #endif 67 } 68 69 /* Mark FILE as close-on-exec. Return FILE. FILE may be NULL, in 70 which case nothing is done. */ 71 static FILE * 72 close_on_exec (FILE *file) 73 { 74 #if defined (HAVE_FILENO) && defined (F_GETFD) 75 if (file) 76 { 77 int fd = fileno (file); 78 int old = fcntl (fd, F_GETFD, 0); 79 if (old >= 0) 80 fcntl (fd, F_SETFD, old | FD_CLOEXEC); 81 } 82 #endif 83 return file; 84 } 85 86 FILE * 87 real_fopen (const char *filename, const char *modes) 88 { 89 #ifdef VMS 90 char vms_modes[4]; 91 char *vms_attr; 92 93 /* On VMS, fopen allows file attributes as optionnal arguments. 94 We need to use them but we'd better to use the common prototype. 95 In fopen-vms.h, they are separated from the mode with a comma. 96 Split here. */ 97 vms_attr = strchr (modes, ','); 98 if (vms_attr == NULL) 99 { 100 /* No attributes. */ 101 return close_on_exec (fopen (filename, modes)); 102 } 103 else 104 { 105 /* Attributes found. Split. */ 106 size_t modes_len = strlen (modes) + 1; 107 char attrs[modes_len + 1]; 108 char *at[3]; 109 int i; 110 111 memcpy (attrs, modes, modes_len); 112 at[0] = attrs; 113 for (i = 0; i < 2; i++) 114 { 115 at[i + 1] = strchr (at[i], ','); 116 BFD_ASSERT (at[i + 1] != NULL); 117 *(at[i + 1]++) = 0; /* Replace ',' with a nul, and skip it. */ 118 } 119 return close_on_exec (fopen (filename, at[0], at[1], at[2])); 120 } 121 #else /* !VMS */ 122 #if defined (HAVE_FOPEN64) 123 return close_on_exec (fopen64 (filename, modes)); 124 #else 125 return close_on_exec (fopen (filename, modes)); 126 #endif 127 #endif /* !VMS */ 128 } 129 130 /* 131 INTERNAL_DEFINITION 132 struct bfd_iovec 133 134 DESCRIPTION 135 136 The <<struct bfd_iovec>> contains the internal file I/O class. 137 Each <<BFD>> has an instance of this class and all file I/O is 138 routed through it (it is assumed that the instance implements 139 all methods listed below). 140 141 .struct bfd_iovec 142 .{ 143 . {* To avoid problems with macros, a "b" rather than "f" 144 . prefix is prepended to each method name. *} 145 . {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching 146 . bytes starting at PTR. Return the number of bytes actually 147 . transfered (a read past end-of-file returns less than NBYTES), 148 . or -1 (setting <<bfd_error>>) if an error occurs. *} 149 . file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes); 150 . file_ptr (*bwrite) (struct bfd *abfd, const void *ptr, 151 . file_ptr nbytes); 152 . {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>> 153 . if an error occurs. *} 154 . file_ptr (*btell) (struct bfd *abfd); 155 . {* For the following, on successful completion a value of 0 is returned. 156 . Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *} 157 . int (*bseek) (struct bfd *abfd, file_ptr offset, int whence); 158 . int (*bclose) (struct bfd *abfd); 159 . int (*bflush) (struct bfd *abfd); 160 . int (*bstat) (struct bfd *abfd, struct stat *sb); 161 . {* Just like mmap: (void*)-1 on failure, mmapped address on success. *} 162 . void *(*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len, 163 . int prot, int flags, file_ptr offset); 164 .}; 165 166 */ 167 168 169 /* Return value is amount read. */ 170 171 bfd_size_type 172 bfd_bread (void *ptr, bfd_size_type size, bfd *abfd) 173 { 174 size_t nread; 175 176 /* If this is an archive element, don't read past the end of 177 this element. */ 178 if (abfd->arelt_data != NULL) 179 { 180 size_t maxbytes = ((struct areltdata *) abfd->arelt_data)->parsed_size; 181 if (size > maxbytes) 182 size = maxbytes; 183 } 184 185 if ((abfd->flags & BFD_IN_MEMORY) != 0) 186 { 187 struct bfd_in_memory *bim; 188 bfd_size_type get; 189 190 bim = (struct bfd_in_memory *) abfd->iostream; 191 get = size; 192 if (abfd->where + get > bim->size) 193 { 194 if (bim->size < (bfd_size_type) abfd->where) 195 get = 0; 196 else 197 get = bim->size - abfd->where; 198 bfd_set_error (bfd_error_file_truncated); 199 } 200 memcpy (ptr, bim->buffer + abfd->where, (size_t) get); 201 abfd->where += get; 202 return get; 203 } 204 205 if (abfd->iovec) 206 nread = abfd->iovec->bread (abfd, ptr, size); 207 else 208 nread = 0; 209 if (nread != (size_t) -1) 210 abfd->where += nread; 211 212 return nread; 213 } 214 215 bfd_size_type 216 bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd) 217 { 218 size_t nwrote; 219 220 if ((abfd->flags & BFD_IN_MEMORY) != 0) 221 { 222 struct bfd_in_memory *bim = (struct bfd_in_memory *) abfd->iostream; 223 224 size = (size_t) size; 225 if (abfd->where + size > bim->size) 226 { 227 bfd_size_type newsize, oldsize; 228 229 oldsize = (bim->size + 127) & ~(bfd_size_type) 127; 230 bim->size = abfd->where + size; 231 /* Round up to cut down on memory fragmentation */ 232 newsize = (bim->size + 127) & ~(bfd_size_type) 127; 233 if (newsize > oldsize) 234 { 235 bim->buffer = (bfd_byte *) bfd_realloc_or_free (bim->buffer, 236 newsize); 237 if (bim->buffer == NULL) 238 { 239 bim->size = 0; 240 return 0; 241 } 242 if (newsize > bim->size) 243 memset (bim->buffer + bim->size, 0, newsize - bim->size); 244 } 245 } 246 memcpy (bim->buffer + abfd->where, ptr, (size_t) size); 247 abfd->where += size; 248 return size; 249 } 250 251 if (abfd->iovec) 252 nwrote = abfd->iovec->bwrite (abfd, ptr, size); 253 else 254 nwrote = 0; 255 256 if (nwrote != (size_t) -1) 257 abfd->where += nwrote; 258 if (nwrote != size) 259 { 260 #ifdef ENOSPC 261 errno = ENOSPC; 262 #endif 263 bfd_set_error (bfd_error_system_call); 264 } 265 return nwrote; 266 } 267 268 file_ptr 269 bfd_tell (bfd *abfd) 270 { 271 file_ptr ptr; 272 273 if ((abfd->flags & BFD_IN_MEMORY) != 0) 274 return abfd->where; 275 276 if (abfd->iovec) 277 { 278 ptr = abfd->iovec->btell (abfd); 279 280 if (abfd->my_archive) 281 ptr -= abfd->origin; 282 } 283 else 284 ptr = 0; 285 286 abfd->where = ptr; 287 return ptr; 288 } 289 290 int 291 bfd_flush (bfd *abfd) 292 { 293 if ((abfd->flags & BFD_IN_MEMORY) != 0) 294 return 0; 295 296 if (abfd->iovec) 297 return abfd->iovec->bflush (abfd); 298 return 0; 299 } 300 301 /* Returns 0 for success, negative value for failure (in which case 302 bfd_get_error can retrieve the error code). */ 303 int 304 bfd_stat (bfd *abfd, struct stat *statbuf) 305 { 306 int result; 307 308 if ((abfd->flags & BFD_IN_MEMORY) != 0) 309 abort (); 310 311 if (abfd->iovec) 312 result = abfd->iovec->bstat (abfd, statbuf); 313 else 314 result = -1; 315 316 if (result < 0) 317 bfd_set_error (bfd_error_system_call); 318 return result; 319 } 320 321 /* Returns 0 for success, nonzero for failure (in which case bfd_get_error 322 can retrieve the error code). */ 323 324 int 325 bfd_seek (bfd *abfd, file_ptr position, int direction) 326 { 327 int result; 328 file_ptr file_position; 329 /* For the time being, a BFD may not seek to it's end. The problem 330 is that we don't easily have a way to recognize the end of an 331 element in an archive. */ 332 333 BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR); 334 335 if (direction == SEEK_CUR && position == 0) 336 return 0; 337 338 if ((abfd->flags & BFD_IN_MEMORY) != 0) 339 { 340 struct bfd_in_memory *bim; 341 342 bim = (struct bfd_in_memory *) abfd->iostream; 343 344 if (direction == SEEK_SET) 345 abfd->where = position; 346 else 347 abfd->where += position; 348 349 if (abfd->where > bim->size) 350 { 351 if (abfd->direction == write_direction 352 || abfd->direction == both_direction) 353 { 354 bfd_size_type newsize, oldsize; 355 356 oldsize = (bim->size + 127) & ~(bfd_size_type) 127; 357 bim->size = abfd->where; 358 /* Round up to cut down on memory fragmentation */ 359 newsize = (bim->size + 127) & ~(bfd_size_type) 127; 360 if (newsize > oldsize) 361 { 362 bim->buffer = (bfd_byte *) bfd_realloc_or_free (bim->buffer, 363 newsize); 364 if (bim->buffer == NULL) 365 { 366 bim->size = 0; 367 return -1; 368 } 369 memset (bim->buffer + oldsize, 0, newsize - oldsize); 370 } 371 } 372 else 373 { 374 abfd->where = bim->size; 375 bfd_set_error (bfd_error_file_truncated); 376 return -1; 377 } 378 } 379 return 0; 380 } 381 382 if (abfd->format != bfd_archive && abfd->my_archive == 0) 383 { 384 if (direction == SEEK_SET && (bfd_vma) position == abfd->where) 385 return 0; 386 } 387 else 388 { 389 /* We need something smarter to optimize access to archives. 390 Currently, anything inside an archive is read via the file 391 handle for the archive. Which means that a bfd_seek on one 392 component affects the `current position' in the archive, as 393 well as in any other component. 394 395 It might be sufficient to put a spike through the cache 396 abstraction, and look to the archive for the file position, 397 but I think we should try for something cleaner. 398 399 In the meantime, no optimization for archives. */ 400 } 401 402 file_position = position; 403 if (direction == SEEK_SET && abfd->my_archive != NULL) 404 file_position += abfd->origin; 405 406 if (abfd->iovec) 407 result = abfd->iovec->bseek (abfd, file_position, direction); 408 else 409 result = -1; 410 411 if (result != 0) 412 { 413 int hold_errno = errno; 414 415 /* Force redetermination of `where' field. */ 416 bfd_tell (abfd); 417 418 /* An EINVAL error probably means that the file offset was 419 absurd. */ 420 if (hold_errno == EINVAL) 421 bfd_set_error (bfd_error_file_truncated); 422 else 423 { 424 bfd_set_error (bfd_error_system_call); 425 errno = hold_errno; 426 } 427 } 428 else 429 { 430 /* Adjust `where' field. */ 431 if (direction == SEEK_SET) 432 abfd->where = position; 433 else 434 abfd->where += position; 435 } 436 return result; 437 } 438 439 /* 440 FUNCTION 441 bfd_get_mtime 442 443 SYNOPSIS 444 long bfd_get_mtime (bfd *abfd); 445 446 DESCRIPTION 447 Return the file modification time (as read from the file system, or 448 from the archive header for archive members). 449 450 */ 451 452 long 453 bfd_get_mtime (bfd *abfd) 454 { 455 struct stat buf; 456 457 if (abfd->mtime_set) 458 return abfd->mtime; 459 460 if (abfd->iovec == NULL) 461 return 0; 462 463 if (abfd->iovec->bstat (abfd, &buf) != 0) 464 return 0; 465 466 abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */ 467 return buf.st_mtime; 468 } 469 470 /* 471 FUNCTION 472 bfd_get_size 473 474 SYNOPSIS 475 file_ptr bfd_get_size (bfd *abfd); 476 477 DESCRIPTION 478 Return the file size (as read from file system) for the file 479 associated with BFD @var{abfd}. 480 481 The initial motivation for, and use of, this routine is not 482 so we can get the exact size of the object the BFD applies to, since 483 that might not be generally possible (archive members for example). 484 It would be ideal if someone could eventually modify 485 it so that such results were guaranteed. 486 487 Instead, we want to ask questions like "is this NNN byte sized 488 object I'm about to try read from file offset YYY reasonable?" 489 As as example of where we might do this, some object formats 490 use string tables for which the first <<sizeof (long)>> bytes of the 491 table contain the size of the table itself, including the size bytes. 492 If an application tries to read what it thinks is one of these 493 string tables, without some way to validate the size, and for 494 some reason the size is wrong (byte swapping error, wrong location 495 for the string table, etc.), the only clue is likely to be a read 496 error when it tries to read the table, or a "virtual memory 497 exhausted" error when it tries to allocate 15 bazillon bytes 498 of space for the 15 bazillon byte table it is about to read. 499 This function at least allows us to answer the question, "is the 500 size reasonable?". 501 */ 502 503 file_ptr 504 bfd_get_size (bfd *abfd) 505 { 506 struct stat buf; 507 508 if ((abfd->flags & BFD_IN_MEMORY) != 0) 509 return ((struct bfd_in_memory *) abfd->iostream)->size; 510 511 if (abfd->iovec == NULL) 512 return 0; 513 514 if (abfd->iovec->bstat (abfd, &buf) != 0) 515 return 0; 516 517 return buf.st_size; 518 } 519 520 521 /* 522 FUNCTION 523 bfd_mmap 524 525 SYNOPSIS 526 void *bfd_mmap (bfd *abfd, void *addr, bfd_size_type len, 527 int prot, int flags, file_ptr offset); 528 529 DESCRIPTION 530 Return mmap()ed region of the file, if possible and implemented. 531 532 */ 533 534 void * 535 bfd_mmap (bfd *abfd, void *addr, bfd_size_type len, 536 int prot, int flags, file_ptr offset) 537 { 538 void *ret = (void *)-1; 539 if ((abfd->flags & BFD_IN_MEMORY) != 0) 540 return ret; 541 542 if (abfd->iovec == NULL) 543 return ret; 544 545 return abfd->iovec->bmmap (abfd, addr, len, prot, flags, offset); 546 } 547