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.
6
This file is part of BFD, the Binary File Descriptor library.
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.
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.
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. */
30
#define S_IXUSR 0100 /* Execute by owner. */
33
#define S_IXGRP 0010 /* Execute by group. */
36
#define S_IXOTH 0001 /* Execute by others. */
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.
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. */
47
real_read (void *where, size_t a, size_t b, FILE *file)
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 */
62
#if defined (__VAX) && defined (VMS)
63
/* Apparently fread on Vax VMS does not keep the record length
65
return read (fileno (file), where, a * b);
67
return fread (where, a, b, file);
71
/* Return value is amount read. */
74
bfd_bread (void *ptr, bfd_size_type size, bfd *abfd)
78
if ((abfd->flags & BFD_IN_MEMORY) != 0)
80
struct bfd_in_memory *bim;
85
if (abfd->where + get > bim->size)
87
if (bim->size < (bfd_size_type) abfd->where)
90
get = bim->size - abfd->where;
91
bfd_set_error (bfd_error_file_truncated);
93
memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
98
nread = real_read (ptr, 1, (size_t) size, bfd_cache_lookup (abfd));
99
if (nread != (size_t) -1)
100
abfd->where += nread;
102
/* Set bfd_error if we did not read as much data as we expected.
104
If the read failed due to an error set the bfd_error_system_call,
105
else set bfd_error_file_truncated.
107
A BFD backend may wish to override bfd_error_file_truncated to
108
provide something more useful (eg. no_symbols or wrong_format). */
111
if (ferror (bfd_cache_lookup (abfd)))
112
bfd_set_error (bfd_error_system_call);
114
bfd_set_error (bfd_error_file_truncated);
121
bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd)
125
if ((abfd->flags & BFD_IN_MEMORY) != 0)
127
struct bfd_in_memory *bim = abfd->iostream;
128
size = (size_t) size;
129
if (abfd->where + size > bim->size)
131
bfd_size_type newsize, oldsize;
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)
139
bim->buffer = bfd_realloc (bim->buffer, newsize);
140
if (bim->buffer == 0)
147
memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
152
nwrote = fwrite (ptr, 1, (size_t) size, bfd_cache_lookup (abfd));
153
if (nwrote != (size_t) -1)
154
abfd->where += nwrote;
160
bfd_set_error (bfd_error_system_call);
170
if ((abfd->flags & BFD_IN_MEMORY) != 0)
173
ptr = ftell (bfd_cache_lookup (abfd));
175
if (abfd->my_archive)
182
bfd_flush (bfd *abfd)
184
if ((abfd->flags & BFD_IN_MEMORY) != 0)
186
return fflush (bfd_cache_lookup(abfd));
189
/* Returns 0 for success, negative value for failure (in which case
190
bfd_get_error can retrieve the error code). */
192
bfd_stat (bfd *abfd, struct stat *statbuf)
197
if ((abfd->flags & BFD_IN_MEMORY) != 0)
200
f = bfd_cache_lookup (abfd);
203
bfd_set_error (bfd_error_system_call);
206
result = fstat (fileno (f), statbuf);
208
bfd_set_error (bfd_error_system_call);
212
/* Returns 0 for success, nonzero for failure (in which case bfd_get_error
213
can retrieve the error code). */
216
bfd_seek (bfd *abfd, file_ptr position, int direction)
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. */
225
BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR);
227
if (direction == SEEK_CUR && position == 0)
230
if ((abfd->flags & BFD_IN_MEMORY) != 0)
232
struct bfd_in_memory *bim;
234
bim = abfd->iostream;
236
if (direction == SEEK_SET)
237
abfd->where = position;
239
abfd->where += position;
241
if (abfd->where > bim->size)
243
if ((abfd->direction == write_direction) ||
244
(abfd->direction == both_direction))
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)
253
bim->buffer = bfd_realloc (bim->buffer, newsize);
254
if (bim->buffer == 0)
263
abfd->where = bim->size;
264
bfd_set_error (bfd_error_file_truncated);
271
if (abfd->format != bfd_archive && abfd->my_archive == 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)
287
if (direction == SEEK_SET && (bfd_vma) position == abfd->where)
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.
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.
302
In the meantime, no optimization for archives. */
305
f = bfd_cache_lookup (abfd);
306
file_position = position;
307
if (direction == SEEK_SET && abfd->my_archive != NULL)
308
file_position += abfd->origin;
310
result = fseek (f, file_position, direction);
313
int hold_errno = errno;
315
/* Force redetermination of `where' field. */
318
/* An EINVAL error probably means that the file offset was
320
if (hold_errno == EINVAL)
321
bfd_set_error (bfd_error_file_truncated);
324
bfd_set_error (bfd_error_system_call);
330
/* Adjust `where' field. */
331
if (direction == SEEK_SET)
332
abfd->where = position;
334
abfd->where += position;
344
long bfd_get_mtime (bfd *abfd);
347
Return the file modification time (as read from the file system, or
348
from the archive header for archive members).
353
bfd_get_mtime (bfd *abfd)
361
fp = bfd_cache_lookup (abfd);
362
if (0 != fstat (fileno (fp), &buf))
365
abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */
374
long bfd_get_size (bfd *abfd);
377
Return the file size (as read from file system) for the file
378
associated with BFD @var{abfd}.
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.
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
403
bfd_get_size (bfd *abfd)
408
if ((abfd->flags & BFD_IN_MEMORY) != 0)
409
return ((struct bfd_in_memory *) abfd->iostream)->size;
411
fp = bfd_cache_lookup (abfd);
412
if (0 != fstat (fileno (fp), & buf))