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