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 Free Software Foundation, Inc. 5 6 Written by Cygnus Support. 7 8This file is part of BFD, the Binary File Descriptor library. 9 10This program is free software; you can redistribute it and/or modify 11it under the terms of the GNU General Public License as published by 12the Free Software Foundation; either version 2 of the License, or 13(at your option) any later version. 14 15This program is distributed in the hope that it will be useful, 16but WITHOUT ANY WARRANTY; without even the implied warranty of 17MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18GNU General Public License for more details. 19 20You should have received a copy of the GNU General Public License 21along with this program; if not, write to the Free Software 22Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ 23 24#include "sysdep.h" 25 26#include "bfd.h" 27#include "libbfd.h" 28 29#include <limits.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 41file_ptr 42real_ftell (FILE *file) 43{ 44#if defined (HAVE_FTELLO64) 45 return ftello64 (file); 46#elif defined (HAVE_FTELLO) 47 return ftello (file); 48#else 49 return ftell (file); 50#endif 51} 52 53int 54real_fseek (FILE *file, file_ptr offset, int whence) 55{ 56#if defined (HAVE_FSEEKO64) 57 return fseeko64 (file, offset, whence); 58#elif defined (HAVE_FSEEKO) 59 return fseeko (file, offset, whence); 60#else 61 return fseek (file, offset, whence); 62#endif 63} 64 65/* 66INTERNAL_DEFINITION 67 struct bfd_iovec 68 69DESCRIPTION 70 71 The <<struct bfd_iovec>> contains the internal file I/O class. 72 Each <<BFD>> has an instance of this class and all file I/O is 73 routed through it (it is assumed that the instance implements 74 all methods listed below). 75 76.struct bfd_iovec 77.{ 78. {* To avoid problems with macros, a "b" rather than "f" 79. prefix is prepended to each method name. *} 80. {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching 81. bytes starting at PTR. Return the number of bytes actually 82. transfered (a read past end-of-file returns less than NBYTES), 83. or -1 (setting <<bfd_error>>) if an error occurs. *} 84. file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes); 85. file_ptr (*bwrite) (struct bfd *abfd, const void *ptr, 86. file_ptr nbytes); 87. {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>> 88. if an error occurs. *} 89. file_ptr (*btell) (struct bfd *abfd); 90. {* For the following, on successful completion a value of 0 is returned. 91. Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *} 92. int (*bseek) (struct bfd *abfd, file_ptr offset, int whence); 93. int (*bclose) (struct bfd *abfd); 94. int (*bflush) (struct bfd *abfd); 95. int (*bstat) (struct bfd *abfd, struct stat *sb); 96.}; 97 98*/ 99 100 101/* Return value is amount read. */ 102 103bfd_size_type 104bfd_bread (void *ptr, bfd_size_type size, bfd *abfd) 105{ 106 size_t nread; 107 108 if ((abfd->flags & BFD_IN_MEMORY) != 0) 109 { 110 struct bfd_in_memory *bim; 111 bfd_size_type get; 112 113 bim = abfd->iostream; 114 get = size; 115 if (abfd->where + get > bim->size) 116 { 117 if (bim->size < (bfd_size_type) abfd->where) 118 get = 0; 119 else 120 get = bim->size - abfd->where; 121 bfd_set_error (bfd_error_file_truncated); 122 } 123 memcpy (ptr, bim->buffer + abfd->where, (size_t) get); 124 abfd->where += get; 125 return get; 126 } 127 128 if (abfd->iovec) 129 nread = abfd->iovec->bread (abfd, ptr, size); 130 else 131 nread = 0; 132 if (nread != (size_t) -1) 133 abfd->where += nread; 134 135 return nread; 136} 137 138bfd_size_type 139bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd) 140{ 141 size_t nwrote; 142 143 if ((abfd->flags & BFD_IN_MEMORY) != 0) 144 { 145 struct bfd_in_memory *bim = abfd->iostream; 146 147 size = (size_t) size; 148 if (abfd->where + size > bim->size) 149 { 150 bfd_size_type newsize, oldsize; 151 152 oldsize = (bim->size + 127) & ~(bfd_size_type) 127; 153 bim->size = abfd->where + size; 154 /* Round up to cut down on memory fragmentation */ 155 newsize = (bim->size + 127) & ~(bfd_size_type) 127; 156 if (newsize > oldsize) 157 { 158 bim->buffer = bfd_realloc (bim->buffer, newsize); 159 if (bim->buffer == 0) 160 { 161 bim->size = 0; 162 return 0; 163 } 164 } 165 } 166 memcpy (bim->buffer + abfd->where, ptr, (size_t) size); 167 abfd->where += size; 168 return size; 169 } 170 171 if (abfd->iovec) 172 nwrote = abfd->iovec->bwrite (abfd, ptr, size); 173 else 174 nwrote = 0; 175 176 if (nwrote != (size_t) -1) 177 abfd->where += nwrote; 178 if (nwrote != size) 179 { 180#ifdef ENOSPC 181 errno = ENOSPC; 182#endif 183 bfd_set_error (bfd_error_system_call); 184 } 185 return nwrote; 186} 187 188file_ptr 189bfd_tell (bfd *abfd) 190{ 191 file_ptr ptr; 192 193 if ((abfd->flags & BFD_IN_MEMORY) != 0) 194 return abfd->where; 195 196 if (abfd->iovec) 197 { 198 ptr = abfd->iovec->btell (abfd); 199 200 if (abfd->my_archive) 201 ptr -= abfd->origin; 202 } 203 else 204 ptr = 0; 205 206 abfd->where = ptr; 207 return ptr; 208} 209 210int 211bfd_flush (bfd *abfd) 212{ 213 if ((abfd->flags & BFD_IN_MEMORY) != 0) 214 return 0; 215 216 if (abfd->iovec) 217 return abfd->iovec->bflush (abfd); 218 return 0; 219} 220 221/* Returns 0 for success, negative value for failure (in which case 222 bfd_get_error can retrieve the error code). */ 223int 224bfd_stat (bfd *abfd, struct stat *statbuf) 225{ 226 int result; 227 228 if ((abfd->flags & BFD_IN_MEMORY) != 0) 229 abort (); 230 231 if (abfd->iovec) 232 result = abfd->iovec->bstat (abfd, statbuf); 233 else 234 result = -1; 235 236 if (result < 0) 237 bfd_set_error (bfd_error_system_call); 238 return result; 239} 240 241/* Returns 0 for success, nonzero for failure (in which case bfd_get_error 242 can retrieve the error code). */ 243 244int 245bfd_seek (bfd *abfd, file_ptr position, int direction) 246{ 247 int result; 248 file_ptr file_position; 249 /* For the time being, a BFD may not seek to it's end. The problem 250 is that we don't easily have a way to recognize the end of an 251 element in an archive. */ 252 253 BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR); 254 255 if (direction == SEEK_CUR && position == 0) 256 return 0; 257 258 if ((abfd->flags & BFD_IN_MEMORY) != 0) 259 { 260 struct bfd_in_memory *bim; 261 262 bim = abfd->iostream; 263 264 if (direction == SEEK_SET) 265 abfd->where = position; 266 else 267 abfd->where += position; 268 269 if (abfd->where > bim->size) 270 { 271 if ((abfd->direction == write_direction) || 272 (abfd->direction == both_direction)) 273 { 274 bfd_size_type newsize, oldsize; 275 276 oldsize = (bim->size + 127) & ~(bfd_size_type) 127; 277 bim->size = abfd->where; 278 /* Round up to cut down on memory fragmentation */ 279 newsize = (bim->size + 127) & ~(bfd_size_type) 127; 280 if (newsize > oldsize) 281 { 282 bim->buffer = bfd_realloc (bim->buffer, newsize); 283 if (bim->buffer == 0) 284 { 285 bim->size = 0; 286 return -1; 287 } 288 } 289 } 290 else 291 { 292 abfd->where = bim->size; 293 bfd_set_error (bfd_error_file_truncated); 294 return -1; 295 } 296 } 297 return 0; 298 } 299 300 if (abfd->format != bfd_archive && abfd->my_archive == 0) 301 { 302#if 0 303 /* Explanation for this code: I'm only about 95+% sure that the above 304 conditions are sufficient and that all i/o calls are properly 305 adjusting the `where' field. So this is sort of an `assert' 306 that the `where' field is correct. If we can go a while without 307 tripping the abort, we can probably safely disable this code, 308 so that the real optimizations happen. */ 309 file_ptr where_am_i_now; 310 where_am_i_now = real_ftell (bfd_cache_lookup (abfd)); 311 if (abfd->my_archive) 312 where_am_i_now -= abfd->origin; 313 if (where_am_i_now != abfd->where) 314 abort (); 315#endif 316 if (direction == SEEK_SET && (bfd_vma) position == abfd->where) 317 return 0; 318 } 319 else 320 { 321 /* We need something smarter to optimize access to archives. 322 Currently, anything inside an archive is read via the file 323 handle for the archive. Which means that a bfd_seek on one 324 component affects the `current position' in the archive, as 325 well as in any other component. 326 327 It might be sufficient to put a spike through the cache 328 abstraction, and look to the archive for the file position, 329 but I think we should try for something cleaner. 330 331 In the meantime, no optimization for archives. */ 332 } 333 334 file_position = position; 335 if (direction == SEEK_SET && abfd->my_archive != NULL) 336 file_position += abfd->origin; 337 338 if (abfd->iovec) 339 result = abfd->iovec->bseek (abfd, file_position, direction); 340 else 341 result = -1; 342 343 if (result != 0) 344 { 345 int hold_errno = errno; 346 347 /* Force redetermination of `where' field. */ 348 bfd_tell (abfd); 349 350 /* An EINVAL error probably means that the file offset was 351 absurd. */ 352 if (hold_errno == EINVAL) 353 bfd_set_error (bfd_error_file_truncated); 354 else 355 { 356 bfd_set_error (bfd_error_system_call); 357 errno = hold_errno; 358 } 359 } 360 else 361 { 362 /* Adjust `where' field. */ 363 if (direction == SEEK_SET) 364 abfd->where = position; 365 else 366 abfd->where += position; 367 } 368 return result; 369} 370 371/* 372FUNCTION 373 bfd_get_mtime 374 375SYNOPSIS 376 long bfd_get_mtime (bfd *abfd); 377 378DESCRIPTION 379 Return the file modification time (as read from the file system, or 380 from the archive header for archive members). 381 382*/ 383 384long 385bfd_get_mtime (bfd *abfd) 386{ 387 struct stat buf; 388 389 if (abfd->mtime_set) 390 return abfd->mtime; 391 392 if (abfd->iovec == NULL) 393 return 0; 394 395 if (abfd->iovec->bstat (abfd, &buf) != 0) 396 return 0; 397 398 abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */ 399 return buf.st_mtime; 400} 401 402/* 403FUNCTION 404 bfd_get_size 405 406SYNOPSIS 407 long bfd_get_size (bfd *abfd); 408 409DESCRIPTION 410 Return the file size (as read from file system) for the file 411 associated with BFD @var{abfd}. 412 413 The initial motivation for, and use of, this routine is not 414 so we can get the exact size of the object the BFD applies to, since 415 that might not be generally possible (archive members for example). 416 It would be ideal if someone could eventually modify 417 it so that such results were guaranteed. 418 419 Instead, we want to ask questions like "is this NNN byte sized 420 object I'm about to try read from file offset YYY reasonable?" 421 As as example of where we might do this, some object formats 422 use string tables for which the first <<sizeof (long)>> bytes of the 423 table contain the size of the table itself, including the size bytes. 424 If an application tries to read what it thinks is one of these 425 string tables, without some way to validate the size, and for 426 some reason the size is wrong (byte swapping error, wrong location 427 for the string table, etc.), the only clue is likely to be a read 428 error when it tries to read the table, or a "virtual memory 429 exhausted" error when it tries to allocate 15 bazillon bytes 430 of space for the 15 bazillon byte table it is about to read. 431 This function at least allows us to answer the question, "is the 432 size reasonable?". 433*/ 434 435long 436bfd_get_size (bfd *abfd) 437{ 438 struct stat buf; 439 440 if ((abfd->flags & BFD_IN_MEMORY) != 0) 441 return ((struct bfd_in_memory *) abfd->iostream)->size; 442 443 if (abfd->iovec == NULL) 444 return 0; 445 446 if (abfd->iovec->bstat (abfd, &buf) != 0) 447 return 0; 448 449 return buf.st_size; 450} 451