| 1 | /* Low-level I/O routines for BFDs. |
| 2 | Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, |
| 3 | 2000, 2001, 2002 Free Software Foundation, Inc. |
| 4 | Written by Cygnus Support. |
| 5 | |
| 6 | This file is part of BFD, the Binary File Descriptor library. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| 21 | |
| 22 | #include "sysdep.h" |
| 23 | |
| 24 | #include "bfd.h" |
| 25 | #include "libbfd.h" |
| 26 | |
| 27 | #include <limits.h> |
| 28 | |
| 29 | #ifndef S_IXUSR |
| 30 | #define S_IXUSR 0100 /* Execute by owner. */ |
| 31 | #endif |
| 32 | #ifndef S_IXGRP |
| 33 | #define S_IXGRP 0010 /* Execute by group. */ |
| 34 | #endif |
| 35 | #ifndef S_IXOTH |
| 36 | #define S_IXOTH 0001 /* Execute by others. */ |
| 37 | #endif |
| 38 | |
| 39 | /* Note that archive entries don't have streams; they share their parent's. |
| 40 | This allows someone to play with the iostream behind BFD's back. |
| 41 | |
| 42 | Also, note that the origin pointer points to the beginning of a file's |
| 43 | contents (0 for non-archive elements). For archive entries this is the |
| 44 | first octet in the file, NOT the beginning of the archive header. */ |
| 45 | |
| 46 | static size_t |
| 47 | real_read (void *where, size_t a, size_t b, FILE *file) |
| 48 | { |
| 49 | /* FIXME - this looks like an optimization, but it's really to cover |
| 50 | up for a feature of some OSs (not solaris - sigh) that |
| 51 | ld/pe-dll.c takes advantage of (apparently) when it creates BFDs |
| 52 | internally and tries to link against them. BFD seems to be smart |
| 53 | enough to realize there are no symbol records in the "file" that |
| 54 | doesn't exist but attempts to read them anyway. On Solaris, |
| 55 | attempting to read zero bytes from a NULL file results in a core |
| 56 | dump, but on other platforms it just returns zero bytes read. |
| 57 | This makes it to something reasonable. - DJ */ |
| 58 | if (a == 0 || b == 0) |
| 59 | return 0; |
| 60 | |
| 61 | |
| 62 | #if defined (__VAX) && defined (VMS) |
| 63 | /* Apparently fread on Vax VMS does not keep the record length |
| 64 | information. */ |
| 65 | return read (fileno (file), where, a * b); |
| 66 | #else |
| 67 | return fread (where, a, b, file); |
| 68 | #endif |
| 69 | } |
| 70 | |
| 71 | /* Return value is amount read. */ |
| 72 | |
| 73 | bfd_size_type |
| 74 | bfd_bread (void *ptr, bfd_size_type size, bfd *abfd) |
| 75 | { |
| 76 | size_t nread; |
| 77 | |
| 78 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 79 | { |
| 80 | struct bfd_in_memory *bim; |
| 81 | bfd_size_type get; |
| 82 | |
| 83 | bim = abfd->iostream; |
| 84 | get = size; |
| 85 | if (abfd->where + get > bim->size) |
| 86 | { |
| 87 | if (bim->size < (bfd_size_type) abfd->where) |
| 88 | get = 0; |
| 89 | else |
| 90 | get = bim->size - abfd->where; |
| 91 | bfd_set_error (bfd_error_file_truncated); |
| 92 | } |
| 93 | memcpy (ptr, bim->buffer + abfd->where, (size_t) get); |
| 94 | abfd->where += get; |
| 95 | return get; |
| 96 | } |
| 97 | |
| 98 | nread = real_read (ptr, 1, (size_t) size, bfd_cache_lookup (abfd)); |
| 99 | if (nread != (size_t) -1) |
| 100 | abfd->where += nread; |
| 101 | |
| 102 | /* Set bfd_error if we did not read as much data as we expected. |
| 103 | |
| 104 | If the read failed due to an error set the bfd_error_system_call, |
| 105 | else set bfd_error_file_truncated. |
| 106 | |
| 107 | A BFD backend may wish to override bfd_error_file_truncated to |
| 108 | provide something more useful (eg. no_symbols or wrong_format). */ |
| 109 | if (nread != size) |
| 110 | { |
| 111 | if (ferror (bfd_cache_lookup (abfd))) |
| 112 | bfd_set_error (bfd_error_system_call); |
| 113 | else |
| 114 | bfd_set_error (bfd_error_file_truncated); |
| 115 | } |
| 116 | |
| 117 | return nread; |
| 118 | } |
| 119 | |
| 120 | bfd_size_type |
| 121 | bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd) |
| 122 | { |
| 123 | size_t nwrote; |
| 124 | |
| 125 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 126 | { |
| 127 | struct bfd_in_memory *bim = abfd->iostream; |
| 128 | size = (size_t) size; |
| 129 | if (abfd->where + size > bim->size) |
| 130 | { |
| 131 | bfd_size_type newsize, oldsize; |
| 132 | |
| 133 | oldsize = (bim->size + 127) & ~(bfd_size_type) 127; |
| 134 | bim->size = abfd->where + size; |
| 135 | /* Round up to cut down on memory fragmentation */ |
| 136 | newsize = (bim->size + 127) & ~(bfd_size_type) 127; |
| 137 | if (newsize > oldsize) |
| 138 | { |
| 139 | bim->buffer = bfd_realloc (bim->buffer, newsize); |
| 140 | if (bim->buffer == 0) |
| 141 | { |
| 142 | bim->size = 0; |
| 143 | return 0; |
| 144 | } |
| 145 | } |
| 146 | } |
| 147 | memcpy (bim->buffer + abfd->where, ptr, (size_t) size); |
| 148 | abfd->where += size; |
| 149 | return size; |
| 150 | } |
| 151 | |
| 152 | nwrote = fwrite (ptr, 1, (size_t) size, bfd_cache_lookup (abfd)); |
| 153 | if (nwrote != (size_t) -1) |
| 154 | abfd->where += nwrote; |
| 155 | if (nwrote != size) |
| 156 | { |
| 157 | #ifdef ENOSPC |
| 158 | errno = ENOSPC; |
| 159 | #endif |
| 160 | bfd_set_error (bfd_error_system_call); |
| 161 | } |
| 162 | return nwrote; |
| 163 | } |
| 164 | |
| 165 | bfd_vma |
| 166 | bfd_tell (bfd *abfd) |
| 167 | { |
| 168 | file_ptr ptr; |
| 169 | |
| 170 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 171 | return abfd->where; |
| 172 | |
| 173 | ptr = ftell (bfd_cache_lookup (abfd)); |
| 174 | |
| 175 | if (abfd->my_archive) |
| 176 | ptr -= abfd->origin; |
| 177 | abfd->where = ptr; |
| 178 | return ptr; |
| 179 | } |
| 180 | |
| 181 | int |
| 182 | bfd_flush (bfd *abfd) |
| 183 | { |
| 184 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 185 | return 0; |
| 186 | return fflush (bfd_cache_lookup(abfd)); |
| 187 | } |
| 188 | |
| 189 | /* Returns 0 for success, negative value for failure (in which case |
| 190 | bfd_get_error can retrieve the error code). */ |
| 191 | int |
| 192 | bfd_stat (bfd *abfd, struct stat *statbuf) |
| 193 | { |
| 194 | FILE *f; |
| 195 | int result; |
| 196 | |
| 197 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 198 | abort (); |
| 199 | |
| 200 | f = bfd_cache_lookup (abfd); |
| 201 | if (f == NULL) |
| 202 | { |
| 203 | bfd_set_error (bfd_error_system_call); |
| 204 | return -1; |
| 205 | } |
| 206 | result = fstat (fileno (f), statbuf); |
| 207 | if (result < 0) |
| 208 | bfd_set_error (bfd_error_system_call); |
| 209 | return result; |
| 210 | } |
| 211 | |
| 212 | /* Returns 0 for success, nonzero for failure (in which case bfd_get_error |
| 213 | can retrieve the error code). */ |
| 214 | |
| 215 | int |
| 216 | bfd_seek (bfd *abfd, file_ptr position, int direction) |
| 217 | { |
| 218 | int result; |
| 219 | FILE *f; |
| 220 | long file_position; |
| 221 | /* For the time being, a BFD may not seek to it's end. The problem |
| 222 | is that we don't easily have a way to recognize the end of an |
| 223 | element in an archive. */ |
| 224 | |
| 225 | BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR); |
| 226 | |
| 227 | if (direction == SEEK_CUR && position == 0) |
| 228 | return 0; |
| 229 | |
| 230 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 231 | { |
| 232 | struct bfd_in_memory *bim; |
| 233 | |
| 234 | bim = abfd->iostream; |
| 235 | |
| 236 | if (direction == SEEK_SET) |
| 237 | abfd->where = position; |
| 238 | else |
| 239 | abfd->where += position; |
| 240 | |
| 241 | if (abfd->where > bim->size) |
| 242 | { |
| 243 | if ((abfd->direction == write_direction) || |
| 244 | (abfd->direction == both_direction)) |
| 245 | { |
| 246 | bfd_size_type newsize, oldsize; |
| 247 | oldsize = (bim->size + 127) & ~(bfd_size_type) 127; |
| 248 | bim->size = abfd->where; |
| 249 | /* Round up to cut down on memory fragmentation */ |
| 250 | newsize = (bim->size + 127) & ~(bfd_size_type) 127; |
| 251 | if (newsize > oldsize) |
| 252 | { |
| 253 | bim->buffer = bfd_realloc (bim->buffer, newsize); |
| 254 | if (bim->buffer == 0) |
| 255 | { |
| 256 | bim->size = 0; |
| 257 | return -1; |
| 258 | } |
| 259 | } |
| 260 | } |
| 261 | else |
| 262 | { |
| 263 | abfd->where = bim->size; |
| 264 | bfd_set_error (bfd_error_file_truncated); |
| 265 | return -1; |
| 266 | } |
| 267 | } |
| 268 | return 0; |
| 269 | } |
| 270 | |
| 271 | if (abfd->format != bfd_archive && abfd->my_archive == 0) |
| 272 | { |
| 273 | #if 0 |
| 274 | /* Explanation for this code: I'm only about 95+% sure that the above |
| 275 | conditions are sufficient and that all i/o calls are properly |
| 276 | adjusting the `where' field. So this is sort of an `assert' |
| 277 | that the `where' field is correct. If we can go a while without |
| 278 | tripping the abort, we can probably safely disable this code, |
| 279 | so that the real optimizations happen. */ |
| 280 | file_ptr where_am_i_now; |
| 281 | where_am_i_now = ftell (bfd_cache_lookup (abfd)); |
| 282 | if (abfd->my_archive) |
| 283 | where_am_i_now -= abfd->origin; |
| 284 | if (where_am_i_now != abfd->where) |
| 285 | abort (); |
| 286 | #endif |
| 287 | if (direction == SEEK_SET && (bfd_vma) position == abfd->where) |
| 288 | return 0; |
| 289 | } |
| 290 | else |
| 291 | { |
| 292 | /* We need something smarter to optimize access to archives. |
| 293 | Currently, anything inside an archive is read via the file |
| 294 | handle for the archive. Which means that a bfd_seek on one |
| 295 | component affects the `current position' in the archive, as |
| 296 | well as in any other component. |
| 297 | |
| 298 | It might be sufficient to put a spike through the cache |
| 299 | abstraction, and look to the archive for the file position, |
| 300 | but I think we should try for something cleaner. |
| 301 | |
| 302 | In the meantime, no optimization for archives. */ |
| 303 | } |
| 304 | |
| 305 | f = bfd_cache_lookup (abfd); |
| 306 | file_position = position; |
| 307 | if (direction == SEEK_SET && abfd->my_archive != NULL) |
| 308 | file_position += abfd->origin; |
| 309 | |
| 310 | result = fseek (f, file_position, direction); |
| 311 | if (result != 0) |
| 312 | { |
| 313 | int hold_errno = errno; |
| 314 | |
| 315 | /* Force redetermination of `where' field. */ |
| 316 | bfd_tell (abfd); |
| 317 | |
| 318 | /* An EINVAL error probably means that the file offset was |
| 319 | absurd. */ |
| 320 | if (hold_errno == EINVAL) |
| 321 | bfd_set_error (bfd_error_file_truncated); |
| 322 | else |
| 323 | { |
| 324 | bfd_set_error (bfd_error_system_call); |
| 325 | errno = hold_errno; |
| 326 | } |
| 327 | } |
| 328 | else |
| 329 | { |
| 330 | /* Adjust `where' field. */ |
| 331 | if (direction == SEEK_SET) |
| 332 | abfd->where = position; |
| 333 | else |
| 334 | abfd->where += position; |
| 335 | } |
| 336 | return result; |
| 337 | } |
| 338 | |
| 339 | /* |
| 340 | FUNCTION |
| 341 | bfd_get_mtime |
| 342 | |
| 343 | SYNOPSIS |
| 344 | long bfd_get_mtime (bfd *abfd); |
| 345 | |
| 346 | DESCRIPTION |
| 347 | Return the file modification time (as read from the file system, or |
| 348 | from the archive header for archive members). |
| 349 | |
| 350 | */ |
| 351 | |
| 352 | long |
| 353 | bfd_get_mtime (bfd *abfd) |
| 354 | { |
| 355 | FILE *fp; |
| 356 | struct stat buf; |
| 357 | |
| 358 | if (abfd->mtime_set) |
| 359 | return abfd->mtime; |
| 360 | |
| 361 | fp = bfd_cache_lookup (abfd); |
| 362 | if (0 != fstat (fileno (fp), &buf)) |
| 363 | return 0; |
| 364 | |
| 365 | abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */ |
| 366 | return buf.st_mtime; |
| 367 | } |
| 368 | |
| 369 | /* |
| 370 | FUNCTION |
| 371 | bfd_get_size |
| 372 | |
| 373 | SYNOPSIS |
| 374 | long bfd_get_size (bfd *abfd); |
| 375 | |
| 376 | DESCRIPTION |
| 377 | Return the file size (as read from file system) for the file |
| 378 | associated with BFD @var{abfd}. |
| 379 | |
| 380 | The initial motivation for, and use of, this routine is not |
| 381 | so we can get the exact size of the object the BFD applies to, since |
| 382 | that might not be generally possible (archive members for example). |
| 383 | It would be ideal if someone could eventually modify |
| 384 | it so that such results were guaranteed. |
| 385 | |
| 386 | Instead, we want to ask questions like "is this NNN byte sized |
| 387 | object I'm about to try read from file offset YYY reasonable?" |
| 388 | As as example of where we might do this, some object formats |
| 389 | use string tables for which the first <<sizeof (long)>> bytes of the |
| 390 | table contain the size of the table itself, including the size bytes. |
| 391 | If an application tries to read what it thinks is one of these |
| 392 | string tables, without some way to validate the size, and for |
| 393 | some reason the size is wrong (byte swapping error, wrong location |
| 394 | for the string table, etc.), the only clue is likely to be a read |
| 395 | error when it tries to read the table, or a "virtual memory |
| 396 | exhausted" error when it tries to allocate 15 bazillon bytes |
| 397 | of space for the 15 bazillon byte table it is about to read. |
| 398 | This function at least allows us to answer the quesion, "is the |
| 399 | size reasonable?". |
| 400 | */ |
| 401 | |
| 402 | long |
| 403 | bfd_get_size (bfd *abfd) |
| 404 | { |
| 405 | FILE *fp; |
| 406 | struct stat buf; |
| 407 | |
| 408 | if ((abfd->flags & BFD_IN_MEMORY) != 0) |
| 409 | return ((struct bfd_in_memory *) abfd->iostream)->size; |
| 410 | |
| 411 | fp = bfd_cache_lookup (abfd); |
| 412 | if (0 != fstat (fileno (fp), & buf)) |
| 413 | return 0; |
| 414 | |
| 415 | return buf.st_size; |
| 416 | } |