| 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 |
| 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 | #if defined (HAVE_FOPEN64) |
| 90 | return close_on_exec (fopen64 (filename, modes)); |
| 91 | #else |
| 92 | return close_on_exec (fopen (filename, modes)); |
| 93 | #endif |
| 94 | } |
| 95 | |
| 96 | /* |
| 97 | INTERNAL_DEFINITION |
| 98 | struct bfd_iovec |
| 99 | |
| 100 | DESCRIPTION |
| 101 | |
| 102 | The <<struct bfd_iovec>> contains the internal file I/O class. |
| 103 | Each <<BFD>> has an instance of this class and all file I/O is |
| 104 | routed through it (it is assumed that the instance implements |
| 105 | all methods listed below). |
| 106 | |
| 107 | .struct bfd_iovec |
| 108 | .{ |
| 109 | . {* To avoid problems with macros, a "b" rather than "f" |
| 110 | . prefix is prepended to each method name. *} |
| 111 | . {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching |
| 112 | . bytes starting at PTR. Return the number of bytes actually |
| 113 | . transfered (a read past end-of-file returns less than NBYTES), |
| 114 | . or -1 (setting <<bfd_error>>) if an error occurs. *} |
| 115 | . file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes); |
| 116 | . file_ptr (*bwrite) (struct bfd *abfd, const void *ptr, |
| 117 | . file_ptr nbytes); |
| 118 | . {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>> |
| 119 | . if an error occurs. *} |
| 120 | . file_ptr (*btell) (struct bfd *abfd); |
| 121 | . {* For the following, on successful completion a value of 0 is returned. |
| 122 | . Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *} |
| 123 | . int (*bseek) (struct bfd *abfd, file_ptr offset, int whence); |
| 124 | . int (*bclose) (struct bfd *abfd); |
| 125 | . int (*bflush) (struct bfd *abfd); |
| 126 | . int (*bstat) (struct bfd *abfd, struct stat *sb); |
| 127 | .}; |
| 128 | |
| 129 | */ |
| 130 | |
| 131 | |
| 132 | /* Return value is amount read. */ |
| 133 | |
| 134 | bfd_size_type |
| 135 | bfd_bread (void *ptr, bfd_size_type size, bfd *abfd) |
| 136 | { |
| 137 | size_t nread; |
| 138 | |
| 139 | /* If this is an archive element, don't read past the end of |
| 140 | this element. */ |
| 141 | if (abfd->arelt_data != NULL) |
| 142 | { |
| 143 | size_t maxbytes = ((struct areltdata *) abfd->arelt_data)->parsed_size; |
| 144 | if (size > maxbytes) |
| 145 | size = maxbytes; |
| 146 | } |
| 147 | |
| 148 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 149 | { |
| 150 | struct bfd_in_memory *bim; |
| 151 | bfd_size_type get; |
| 152 | |
| 153 | bim = abfd->iostream; |
| 154 | get = size; |
| 155 | if (abfd->where + get > bim->size) |
| 156 | { |
| 157 | if (bim->size < (bfd_size_type) abfd->where) |
| 158 | get = 0; |
| 159 | else |
| 160 | get = bim->size - abfd->where; |
| 161 | bfd_set_error (bfd_error_file_truncated); |
| 162 | } |
| 163 | memcpy (ptr, bim->buffer + abfd->where, (size_t) get); |
| 164 | abfd->where += get; |
| 165 | return get; |
| 166 | } |
| 167 | |
| 168 | if (abfd->iovec) |
| 169 | nread = abfd->iovec->bread (abfd, ptr, size); |
| 170 | else |
| 171 | nread = 0; |
| 172 | if (nread != (size_t) -1) |
| 173 | abfd->where += nread; |
| 174 | |
| 175 | return nread; |
| 176 | } |
| 177 | |
| 178 | bfd_size_type |
| 179 | bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd) |
| 180 | { |
| 181 | size_t nwrote; |
| 182 | |
| 183 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 184 | { |
| 185 | struct bfd_in_memory *bim = abfd->iostream; |
| 186 | |
| 187 | size = (size_t) size; |
| 188 | if (abfd->where + size > bim->size) |
| 189 | { |
| 190 | bfd_size_type newsize, oldsize; |
| 191 | |
| 192 | oldsize = (bim->size + 127) & ~(bfd_size_type) 127; |
| 193 | bim->size = abfd->where + size; |
| 194 | /* Round up to cut down on memory fragmentation */ |
| 195 | newsize = (bim->size + 127) & ~(bfd_size_type) 127; |
| 196 | if (newsize > oldsize) |
| 197 | { |
| 198 | bim->buffer = bfd_realloc_or_free (bim->buffer, newsize); |
| 199 | if (bim->buffer == NULL) |
| 200 | { |
| 201 | bim->size = 0; |
| 202 | return 0; |
| 203 | } |
| 204 | } |
| 205 | } |
| 206 | memcpy (bim->buffer + abfd->where, ptr, (size_t) size); |
| 207 | abfd->where += size; |
| 208 | return size; |
| 209 | } |
| 210 | |
| 211 | if (abfd->iovec) |
| 212 | nwrote = abfd->iovec->bwrite (abfd, ptr, size); |
| 213 | else |
| 214 | nwrote = 0; |
| 215 | |
| 216 | if (nwrote != (size_t) -1) |
| 217 | abfd->where += nwrote; |
| 218 | if (nwrote != size) |
| 219 | { |
| 220 | #ifdef ENOSPC |
| 221 | errno = ENOSPC; |
| 222 | #endif |
| 223 | bfd_set_error (bfd_error_system_call); |
| 224 | } |
| 225 | return nwrote; |
| 226 | } |
| 227 | |
| 228 | file_ptr |
| 229 | bfd_tell (bfd *abfd) |
| 230 | { |
| 231 | file_ptr ptr; |
| 232 | |
| 233 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 234 | return abfd->where; |
| 235 | |
| 236 | if (abfd->iovec) |
| 237 | { |
| 238 | ptr = abfd->iovec->btell (abfd); |
| 239 | |
| 240 | if (abfd->my_archive) |
| 241 | ptr -= abfd->origin; |
| 242 | } |
| 243 | else |
| 244 | ptr = 0; |
| 245 | |
| 246 | abfd->where = ptr; |
| 247 | return ptr; |
| 248 | } |
| 249 | |
| 250 | int |
| 251 | bfd_flush (bfd *abfd) |
| 252 | { |
| 253 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 254 | return 0; |
| 255 | |
| 256 | if (abfd->iovec) |
| 257 | return abfd->iovec->bflush (abfd); |
| 258 | return 0; |
| 259 | } |
| 260 | |
| 261 | /* Returns 0 for success, negative value for failure (in which case |
| 262 | bfd_get_error can retrieve the error code). */ |
| 263 | int |
| 264 | bfd_stat (bfd *abfd, struct stat *statbuf) |
| 265 | { |
| 266 | int result; |
| 267 | |
| 268 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 269 | abort (); |
| 270 | |
| 271 | if (abfd->iovec) |
| 272 | result = abfd->iovec->bstat (abfd, statbuf); |
| 273 | else |
| 274 | result = -1; |
| 275 | |
| 276 | if (result < 0) |
| 277 | bfd_set_error (bfd_error_system_call); |
| 278 | return result; |
| 279 | } |
| 280 | |
| 281 | /* Returns 0 for success, nonzero for failure (in which case bfd_get_error |
| 282 | can retrieve the error code). */ |
| 283 | |
| 284 | int |
| 285 | bfd_seek (bfd *abfd, file_ptr position, int direction) |
| 286 | { |
| 287 | int result; |
| 288 | file_ptr file_position; |
| 289 | /* For the time being, a BFD may not seek to it's end. The problem |
| 290 | is that we don't easily have a way to recognize the end of an |
| 291 | element in an archive. */ |
| 292 | |
| 293 | BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR); |
| 294 | |
| 295 | if (direction == SEEK_CUR && position == 0) |
| 296 | return 0; |
| 297 | |
| 298 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 299 | { |
| 300 | struct bfd_in_memory *bim; |
| 301 | |
| 302 | bim = abfd->iostream; |
| 303 | |
| 304 | if (direction == SEEK_SET) |
| 305 | abfd->where = position; |
| 306 | else |
| 307 | abfd->where += position; |
| 308 | |
| 309 | if (abfd->where > bim->size) |
| 310 | { |
| 311 | if ((abfd->direction == write_direction) || |
| 312 | (abfd->direction == both_direction)) |
| 313 | { |
| 314 | bfd_size_type newsize, oldsize; |
| 315 | |
| 316 | oldsize = (bim->size + 127) & ~(bfd_size_type) 127; |
| 317 | bim->size = abfd->where; |
| 318 | /* Round up to cut down on memory fragmentation */ |
| 319 | newsize = (bim->size + 127) & ~(bfd_size_type) 127; |
| 320 | if (newsize > oldsize) |
| 321 | { |
| 322 | bim->buffer = bfd_realloc_or_free (bim->buffer, newsize); |
| 323 | if (bim->buffer == NULL) |
| 324 | { |
| 325 | bim->size = 0; |
| 326 | return -1; |
| 327 | } |
| 328 | } |
| 329 | } |
| 330 | else |
| 331 | { |
| 332 | abfd->where = bim->size; |
| 333 | bfd_set_error (bfd_error_file_truncated); |
| 334 | return -1; |
| 335 | } |
| 336 | } |
| 337 | return 0; |
| 338 | } |
| 339 | |
| 340 | if (abfd->format != bfd_archive && abfd->my_archive == 0) |
| 341 | { |
| 342 | if (direction == SEEK_SET && (bfd_vma) position == abfd->where) |
| 343 | return 0; |
| 344 | } |
| 345 | else |
| 346 | { |
| 347 | /* We need something smarter to optimize access to archives. |
| 348 | Currently, anything inside an archive is read via the file |
| 349 | handle for the archive. Which means that a bfd_seek on one |
| 350 | component affects the `current position' in the archive, as |
| 351 | well as in any other component. |
| 352 | |
| 353 | It might be sufficient to put a spike through the cache |
| 354 | abstraction, and look to the archive for the file position, |
| 355 | but I think we should try for something cleaner. |
| 356 | |
| 357 | In the meantime, no optimization for archives. */ |
| 358 | } |
| 359 | |
| 360 | file_position = position; |
| 361 | if (direction == SEEK_SET && abfd->my_archive != NULL) |
| 362 | file_position += abfd->origin; |
| 363 | |
| 364 | if (abfd->iovec) |
| 365 | result = abfd->iovec->bseek (abfd, file_position, direction); |
| 366 | else |
| 367 | result = -1; |
| 368 | |
| 369 | if (result != 0) |
| 370 | { |
| 371 | int hold_errno = errno; |
| 372 | |
| 373 | /* Force redetermination of `where' field. */ |
| 374 | bfd_tell (abfd); |
| 375 | |
| 376 | /* An EINVAL error probably means that the file offset was |
| 377 | absurd. */ |
| 378 | if (hold_errno == EINVAL) |
| 379 | bfd_set_error (bfd_error_file_truncated); |
| 380 | else |
| 381 | { |
| 382 | bfd_set_error (bfd_error_system_call); |
| 383 | errno = hold_errno; |
| 384 | } |
| 385 | } |
| 386 | else |
| 387 | { |
| 388 | /* Adjust `where' field. */ |
| 389 | if (direction == SEEK_SET) |
| 390 | abfd->where = position; |
| 391 | else |
| 392 | abfd->where += position; |
| 393 | } |
| 394 | return result; |
| 395 | } |
| 396 | |
| 397 | /* |
| 398 | FUNCTION |
| 399 | bfd_get_mtime |
| 400 | |
| 401 | SYNOPSIS |
| 402 | long bfd_get_mtime (bfd *abfd); |
| 403 | |
| 404 | DESCRIPTION |
| 405 | Return the file modification time (as read from the file system, or |
| 406 | from the archive header for archive members). |
| 407 | |
| 408 | */ |
| 409 | |
| 410 | long |
| 411 | bfd_get_mtime (bfd *abfd) |
| 412 | { |
| 413 | struct stat buf; |
| 414 | |
| 415 | if (abfd->mtime_set) |
| 416 | return abfd->mtime; |
| 417 | |
| 418 | if (abfd->iovec == NULL) |
| 419 | return 0; |
| 420 | |
| 421 | if (abfd->iovec->bstat (abfd, &buf) != 0) |
| 422 | return 0; |
| 423 | |
| 424 | abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */ |
| 425 | return buf.st_mtime; |
| 426 | } |
| 427 | |
| 428 | /* |
| 429 | FUNCTION |
| 430 | bfd_get_size |
| 431 | |
| 432 | SYNOPSIS |
| 433 | file_ptr bfd_get_size (bfd *abfd); |
| 434 | |
| 435 | DESCRIPTION |
| 436 | Return the file size (as read from file system) for the file |
| 437 | associated with BFD @var{abfd}. |
| 438 | |
| 439 | The initial motivation for, and use of, this routine is not |
| 440 | so we can get the exact size of the object the BFD applies to, since |
| 441 | that might not be generally possible (archive members for example). |
| 442 | It would be ideal if someone could eventually modify |
| 443 | it so that such results were guaranteed. |
| 444 | |
| 445 | Instead, we want to ask questions like "is this NNN byte sized |
| 446 | object I'm about to try read from file offset YYY reasonable?" |
| 447 | As as example of where we might do this, some object formats |
| 448 | use string tables for which the first <<sizeof (long)>> bytes of the |
| 449 | table contain the size of the table itself, including the size bytes. |
| 450 | If an application tries to read what it thinks is one of these |
| 451 | string tables, without some way to validate the size, and for |
| 452 | some reason the size is wrong (byte swapping error, wrong location |
| 453 | for the string table, etc.), the only clue is likely to be a read |
| 454 | error when it tries to read the table, or a "virtual memory |
| 455 | exhausted" error when it tries to allocate 15 bazillon bytes |
| 456 | of space for the 15 bazillon byte table it is about to read. |
| 457 | This function at least allows us to answer the question, "is the |
| 458 | size reasonable?". |
| 459 | */ |
| 460 | |
| 461 | file_ptr |
| 462 | bfd_get_size (bfd *abfd) |
| 463 | { |
| 464 | struct stat buf; |
| 465 | |
| 466 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 467 | return ((struct bfd_in_memory *) abfd->iostream)->size; |
| 468 | |
| 469 | if (abfd->iovec == NULL) |
| 470 | return 0; |
| 471 | |
| 472 | if (abfd->iovec->bstat (abfd, &buf) != 0) |
| 473 | return 0; |
| 474 | |
| 475 | return buf.st_size; |
| 476 | } |