* alpha.c, basic_blocks.c, basic_blocks.h, bb_exit_func.c,
[binutils.git] / bfd / bfdio.c
bloba7505270199c7e972bf0bca0440c18e64eeb04d3
1 /* Low-level I/O routines for BFDs.
3 Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
4 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
6 Written by Cygnus Support.
8 This file is part of BFD, the Binary File Descriptor library.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to the Free Software
22 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
24 #include "sysdep.h"
26 #include "bfd.h"
27 #include "libbfd.h"
29 #include <limits.h>
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
41 file_ptr
42 real_ftell (FILE *file)
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
53 int
54 real_fseek (FILE *file, file_ptr offset, int whence)
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
66 INTERNAL_DEFINITION
67 struct bfd_iovec
69 DESCRIPTION
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).
76 .struct bfd_iovec
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 .};
101 /* Return value is amount read. */
103 bfd_size_type
104 bfd_bread (void *ptr, bfd_size_type size, bfd *abfd)
106 size_t nread;
108 if ((abfd->flags & BFD_IN_MEMORY) != 0)
110 struct bfd_in_memory *bim;
111 bfd_size_type get;
113 bim = abfd->iostream;
114 get = size;
115 if (abfd->where + get > bim->size)
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);
123 memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
124 abfd->where += get;
125 return get;
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;
135 return nread;
138 bfd_size_type
139 bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd)
141 size_t nwrote;
143 if ((abfd->flags & BFD_IN_MEMORY) != 0)
145 struct bfd_in_memory *bim = abfd->iostream;
147 size = (size_t) size;
148 if (abfd->where + size > bim->size)
150 bfd_size_type newsize, oldsize;
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)
158 bim->buffer = bfd_realloc (bim->buffer, newsize);
159 if (bim->buffer == 0)
161 bim->size = 0;
162 return 0;
166 memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
167 abfd->where += size;
168 return size;
171 if (abfd->iovec)
172 nwrote = abfd->iovec->bwrite (abfd, ptr, size);
173 else
174 nwrote = 0;
176 if (nwrote != (size_t) -1)
177 abfd->where += nwrote;
178 if (nwrote != size)
180 #ifdef ENOSPC
181 errno = ENOSPC;
182 #endif
183 bfd_set_error (bfd_error_system_call);
185 return nwrote;
188 file_ptr
189 bfd_tell (bfd *abfd)
191 file_ptr ptr;
193 if ((abfd->flags & BFD_IN_MEMORY) != 0)
194 return abfd->where;
196 if (abfd->iovec)
198 ptr = abfd->iovec->btell (abfd);
200 if (abfd->my_archive)
201 ptr -= abfd->origin;
203 else
204 ptr = 0;
206 abfd->where = ptr;
207 return ptr;
211 bfd_flush (bfd *abfd)
213 if ((abfd->flags & BFD_IN_MEMORY) != 0)
214 return 0;
216 if (abfd->iovec)
217 return abfd->iovec->bflush (abfd);
218 return 0;
221 /* Returns 0 for success, negative value for failure (in which case
222 bfd_get_error can retrieve the error code). */
224 bfd_stat (bfd *abfd, struct stat *statbuf)
226 int result;
228 if ((abfd->flags & BFD_IN_MEMORY) != 0)
229 abort ();
231 if (abfd->iovec)
232 result = abfd->iovec->bstat (abfd, statbuf);
233 else
234 result = -1;
236 if (result < 0)
237 bfd_set_error (bfd_error_system_call);
238 return result;
241 /* Returns 0 for success, nonzero for failure (in which case bfd_get_error
242 can retrieve the error code). */
245 bfd_seek (bfd *abfd, file_ptr position, int direction)
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. */
253 BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR);
255 if (direction == SEEK_CUR && position == 0)
256 return 0;
258 if ((abfd->flags & BFD_IN_MEMORY) != 0)
260 struct bfd_in_memory *bim;
262 bim = abfd->iostream;
264 if (direction == SEEK_SET)
265 abfd->where = position;
266 else
267 abfd->where += position;
269 if (abfd->where > bim->size)
271 if ((abfd->direction == write_direction) ||
272 (abfd->direction == both_direction))
274 bfd_size_type newsize, oldsize;
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)
282 bim->buffer = bfd_realloc (bim->buffer, newsize);
283 if (bim->buffer == 0)
285 bim->size = 0;
286 return -1;
290 else
292 abfd->where = bim->size;
293 bfd_set_error (bfd_error_file_truncated);
294 return -1;
297 return 0;
300 if (abfd->format != bfd_archive && abfd->my_archive == 0)
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;
319 else
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.
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.
331 In the meantime, no optimization for archives. */
334 file_position = position;
335 if (direction == SEEK_SET && abfd->my_archive != NULL)
336 file_position += abfd->origin;
338 if (abfd->iovec)
339 result = abfd->iovec->bseek (abfd, file_position, direction);
340 else
341 result = -1;
343 if (result != 0)
345 int hold_errno = errno;
347 /* Force redetermination of `where' field. */
348 bfd_tell (abfd);
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
356 bfd_set_error (bfd_error_system_call);
357 errno = hold_errno;
360 else
362 /* Adjust `where' field. */
363 if (direction == SEEK_SET)
364 abfd->where = position;
365 else
366 abfd->where += position;
368 return result;
372 FUNCTION
373 bfd_get_mtime
375 SYNOPSIS
376 long bfd_get_mtime (bfd *abfd);
378 DESCRIPTION
379 Return the file modification time (as read from the file system, or
380 from the archive header for archive members).
384 long
385 bfd_get_mtime (bfd *abfd)
387 struct stat buf;
389 if (abfd->mtime_set)
390 return abfd->mtime;
392 if (abfd->iovec == NULL)
393 return 0;
395 if (abfd->iovec->bstat (abfd, &buf) != 0)
396 return 0;
398 abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */
399 return buf.st_mtime;
403 FUNCTION
404 bfd_get_size
406 SYNOPSIS
407 long bfd_get_size (bfd *abfd);
409 DESCRIPTION
410 Return the file size (as read from file system) for the file
411 associated with BFD @var{abfd}.
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.
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?".
435 long
436 bfd_get_size (bfd *abfd)
438 struct stat buf;
440 if ((abfd->flags & BFD_IN_MEMORY) != 0)
441 return ((struct bfd_in_memory *) abfd->iostream)->size;
443 if (abfd->iovec == NULL)
444 return 0;
446 if (abfd->iovec->bstat (abfd, &buf) != 0)
447 return 0;
449 return buf.st_size;