bfdio.c revision 218822
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 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#include <limits.h> 27#include "bfd.h" 28#include "libbfd.h" 29 30#ifndef S_IXUSR 31#define S_IXUSR 0100 /* Execute by owner. */ 32#endif 33#ifndef S_IXGRP 34#define S_IXGRP 0010 /* Execute by group. */ 35#endif 36#ifndef S_IXOTH 37#define S_IXOTH 0001 /* Execute by others. */ 38#endif 39 40file_ptr 41real_ftell (FILE *file) 42{ 43#if defined (HAVE_FTELLO64) 44 return ftello64 (file); 45#elif defined (HAVE_FTELLO) 46 return ftello (file); 47#else 48 return ftell (file); 49#endif 50} 51 52int 53real_fseek (FILE *file, file_ptr offset, int whence) 54{ 55#if defined (HAVE_FSEEKO64) 56 return fseeko64 (file, offset, whence); 57#elif defined (HAVE_FSEEKO) 58 return fseeko (file, offset, whence); 59#else 60 return fseek (file, offset, whence); 61#endif 62} 63 64FILE * 65real_fopen (const char *filename, const char *modes) 66{ 67#if defined (HAVE_FOPEN64) 68 return fopen64 (filename, modes); 69#else 70 return fopen (filename, modes); 71#endif 72} 73 74/* 75INTERNAL_DEFINITION 76 struct bfd_iovec 77 78DESCRIPTION 79 80 The <<struct bfd_iovec>> contains the internal file I/O class. 81 Each <<BFD>> has an instance of this class and all file I/O is 82 routed through it (it is assumed that the instance implements 83 all methods listed below). 84 85.struct bfd_iovec 86.{ 87. {* To avoid problems with macros, a "b" rather than "f" 88. prefix is prepended to each method name. *} 89. {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching 90. bytes starting at PTR. Return the number of bytes actually 91. transfered (a read past end-of-file returns less than NBYTES), 92. or -1 (setting <<bfd_error>>) if an error occurs. *} 93. file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes); 94. file_ptr (*bwrite) (struct bfd *abfd, const void *ptr, 95. file_ptr nbytes); 96. {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>> 97. if an error occurs. *} 98. file_ptr (*btell) (struct bfd *abfd); 99. {* For the following, on successful completion a value of 0 is returned. 100. Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *} 101. int (*bseek) (struct bfd *abfd, file_ptr offset, int whence); 102. int (*bclose) (struct bfd *abfd); 103. int (*bflush) (struct bfd *abfd); 104. int (*bstat) (struct bfd *abfd, struct stat *sb); 105.}; 106 107*/ 108 109 110/* Return value is amount read. */ 111 112bfd_size_type 113bfd_bread (void *ptr, bfd_size_type size, bfd *abfd) 114{ 115 size_t nread; 116 117 /* If this is an archive element, don't read past the end of 118 this element. */ 119 if (abfd->arelt_data != NULL) 120 { 121 size_t maxbytes = ((struct areltdata *) abfd->arelt_data)->parsed_size; 122 if (size > maxbytes) 123 size = maxbytes; 124 } 125 126 if ((abfd->flags & BFD_IN_MEMORY) != 0) 127 { 128 struct bfd_in_memory *bim; 129 bfd_size_type get; 130 131 bim = abfd->iostream; 132 get = size; 133 if (abfd->where + get > bim->size) 134 { 135 if (bim->size < (bfd_size_type) abfd->where) 136 get = 0; 137 else 138 get = bim->size - abfd->where; 139 bfd_set_error (bfd_error_file_truncated); 140 } 141 memcpy (ptr, bim->buffer + abfd->where, (size_t) get); 142 abfd->where += get; 143 return get; 144 } 145 146 if (abfd->iovec) 147 nread = abfd->iovec->bread (abfd, ptr, size); 148 else 149 nread = 0; 150 if (nread != (size_t) -1) 151 abfd->where += nread; 152 153 return nread; 154} 155 156bfd_size_type 157bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd) 158{ 159 size_t nwrote; 160 161 if ((abfd->flags & BFD_IN_MEMORY) != 0) 162 { 163 struct bfd_in_memory *bim = abfd->iostream; 164 165 size = (size_t) size; 166 if (abfd->where + size > bim->size) 167 { 168 bfd_size_type newsize, oldsize; 169 170 oldsize = (bim->size + 127) & ~(bfd_size_type) 127; 171 bim->size = abfd->where + size; 172 /* Round up to cut down on memory fragmentation */ 173 newsize = (bim->size + 127) & ~(bfd_size_type) 127; 174 if (newsize > oldsize) 175 { 176 bim->buffer = bfd_realloc (bim->buffer, newsize); 177 if (bim->buffer == 0) 178 { 179 bim->size = 0; 180 return 0; 181 } 182 } 183 } 184 memcpy (bim->buffer + abfd->where, ptr, (size_t) size); 185 abfd->where += size; 186 return size; 187 } 188 189 if (abfd->iovec) 190 nwrote = abfd->iovec->bwrite (abfd, ptr, size); 191 else 192 nwrote = 0; 193 194 if (nwrote != (size_t) -1) 195 abfd->where += nwrote; 196 if (nwrote != size) 197 { 198#ifdef ENOSPC 199 errno = ENOSPC; 200#endif 201 bfd_set_error (bfd_error_system_call); 202 } 203 return nwrote; 204} 205 206file_ptr 207bfd_tell (bfd *abfd) 208{ 209 file_ptr ptr; 210 211 if ((abfd->flags & BFD_IN_MEMORY) != 0) 212 return abfd->where; 213 214 if (abfd->iovec) 215 { 216 ptr = abfd->iovec->btell (abfd); 217 218 if (abfd->my_archive) 219 ptr -= abfd->origin; 220 } 221 else 222 ptr = 0; 223 224 abfd->where = ptr; 225 return ptr; 226} 227 228int 229bfd_flush (bfd *abfd) 230{ 231 if ((abfd->flags & BFD_IN_MEMORY) != 0) 232 return 0; 233 234 if (abfd->iovec) 235 return abfd->iovec->bflush (abfd); 236 return 0; 237} 238 239/* Returns 0 for success, negative value for failure (in which case 240 bfd_get_error can retrieve the error code). */ 241int 242bfd_stat (bfd *abfd, struct stat *statbuf) 243{ 244 int result; 245 246 if ((abfd->flags & BFD_IN_MEMORY) != 0) 247 abort (); 248 249 if (abfd->iovec) 250 result = abfd->iovec->bstat (abfd, statbuf); 251 else 252 result = -1; 253 254 if (result < 0) 255 bfd_set_error (bfd_error_system_call); 256 return result; 257} 258 259/* Returns 0 for success, nonzero for failure (in which case bfd_get_error 260 can retrieve the error code). */ 261 262int 263bfd_seek (bfd *abfd, file_ptr position, int direction) 264{ 265 int result; 266 file_ptr file_position; 267 /* For the time being, a BFD may not seek to it's end. The problem 268 is that we don't easily have a way to recognize the end of an 269 element in an archive. */ 270 271 BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR); 272 273 if (direction == SEEK_CUR && position == 0) 274 return 0; 275 276 if ((abfd->flags & BFD_IN_MEMORY) != 0) 277 { 278 struct bfd_in_memory *bim; 279 280 bim = abfd->iostream; 281 282 if (direction == SEEK_SET) 283 abfd->where = position; 284 else 285 abfd->where += position; 286 287 if (abfd->where > bim->size) 288 { 289 if ((abfd->direction == write_direction) || 290 (abfd->direction == both_direction)) 291 { 292 bfd_size_type newsize, oldsize; 293 294 oldsize = (bim->size + 127) & ~(bfd_size_type) 127; 295 bim->size = abfd->where; 296 /* Round up to cut down on memory fragmentation */ 297 newsize = (bim->size + 127) & ~(bfd_size_type) 127; 298 if (newsize > oldsize) 299 { 300 bim->buffer = bfd_realloc (bim->buffer, newsize); 301 if (bim->buffer == 0) 302 { 303 bim->size = 0; 304 return -1; 305 } 306 } 307 } 308 else 309 { 310 abfd->where = bim->size; 311 bfd_set_error (bfd_error_file_truncated); 312 return -1; 313 } 314 } 315 return 0; 316 } 317 318 if (abfd->format != bfd_archive && abfd->my_archive == 0) 319 { 320 if (direction == SEEK_SET && (bfd_vma) position == abfd->where) 321 return 0; 322 } 323 else 324 { 325 /* We need something smarter to optimize access to archives. 326 Currently, anything inside an archive is read via the file 327 handle for the archive. Which means that a bfd_seek on one 328 component affects the `current position' in the archive, as 329 well as in any other component. 330 331 It might be sufficient to put a spike through the cache 332 abstraction, and look to the archive for the file position, 333 but I think we should try for something cleaner. 334 335 In the meantime, no optimization for archives. */ 336 } 337 338 file_position = position; 339 if (direction == SEEK_SET && abfd->my_archive != NULL) 340 file_position += abfd->origin; 341 342 if (abfd->iovec) 343 result = abfd->iovec->bseek (abfd, file_position, direction); 344 else 345 result = -1; 346 347 if (result != 0) 348 { 349 int hold_errno = errno; 350 351 /* Force redetermination of `where' field. */ 352 bfd_tell (abfd); 353 354 /* An EINVAL error probably means that the file offset was 355 absurd. */ 356 if (hold_errno == EINVAL) 357 bfd_set_error (bfd_error_file_truncated); 358 else 359 { 360 bfd_set_error (bfd_error_system_call); 361 errno = hold_errno; 362 } 363 } 364 else 365 { 366 /* Adjust `where' field. */ 367 if (direction == SEEK_SET) 368 abfd->where = position; 369 else 370 abfd->where += position; 371 } 372 return result; 373} 374 375/* 376FUNCTION 377 bfd_get_mtime 378 379SYNOPSIS 380 long bfd_get_mtime (bfd *abfd); 381 382DESCRIPTION 383 Return the file modification time (as read from the file system, or 384 from the archive header for archive members). 385 386*/ 387 388long 389bfd_get_mtime (bfd *abfd) 390{ 391 struct stat buf; 392 393 if (abfd->mtime_set) 394 return abfd->mtime; 395 396 if (abfd->iovec == NULL) 397 return 0; 398 399 if (abfd->iovec->bstat (abfd, &buf) != 0) 400 return 0; 401 402 abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */ 403 return buf.st_mtime; 404} 405 406/* 407FUNCTION 408 bfd_get_size 409 410SYNOPSIS 411 file_ptr bfd_get_size (bfd *abfd); 412 413DESCRIPTION 414 Return the file size (as read from file system) for the file 415 associated with BFD @var{abfd}. 416 417 The initial motivation for, and use of, this routine is not 418 so we can get the exact size of the object the BFD applies to, since 419 that might not be generally possible (archive members for example). 420 It would be ideal if someone could eventually modify 421 it so that such results were guaranteed. 422 423 Instead, we want to ask questions like "is this NNN byte sized 424 object I'm about to try read from file offset YYY reasonable?" 425 As as example of where we might do this, some object formats 426 use string tables for which the first <<sizeof (long)>> bytes of the 427 table contain the size of the table itself, including the size bytes. 428 If an application tries to read what it thinks is one of these 429 string tables, without some way to validate the size, and for 430 some reason the size is wrong (byte swapping error, wrong location 431 for the string table, etc.), the only clue is likely to be a read 432 error when it tries to read the table, or a "virtual memory 433 exhausted" error when it tries to allocate 15 bazillon bytes 434 of space for the 15 bazillon byte table it is about to read. 435 This function at least allows us to answer the question, "is the 436 size reasonable?". 437*/ 438 439file_ptr 440bfd_get_size (bfd *abfd) 441{ 442 struct stat buf; 443 444 if ((abfd->flags & BFD_IN_MEMORY) != 0) 445 return ((struct bfd_in_memory *) abfd->iostream)->size; 446 447 if (abfd->iovec == NULL) 448 return 0; 449 450 if (abfd->iovec->bstat (abfd, &buf) != 0) 451 return 0; 452 453 return buf.st_size; 454} 455