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
5 Free Software Foundation, Inc.
6
7 Written by Cygnus Support.
8
9 This file is part of BFD, the Binary File Descriptor library.
10
11 This program is free software; you can redistribute it and/or modify
12 it under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 2 of the License, or
14 (at your option) any later version.
15
16 This program is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 GNU General Public License for more details.
20
21 You should have received a copy of the GNU General Public License
22 along with this program; if not, write to the Free Software
23 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
24
25 #include "sysdep.h"
26
27 #include "bfd.h"
28 #include "libbfd.h"
29
30 #include <limits.h>
31
32 #ifndef S_IXUSR
33 #define S_IXUSR 0100 /* Execute by owner. */
34 #endif
35 #ifndef S_IXGRP
36 #define S_IXGRP 0010 /* Execute by group. */
37 #endif
38 #ifndef S_IXOTH
39 #define S_IXOTH 0001 /* Execute by others. */
40 #endif
41
42 file_ptr
real_ftell(FILE * file)43 real_ftell (FILE *file)
44 {
45 #if defined (HAVE_FTELLO64)
46 return ftello64 (file);
47 #elif defined (HAVE_FTELLO)
48 return ftello (file);
49 #else
50 return ftell (file);
51 #endif
52 }
53
54 int
real_fseek(FILE * file,file_ptr offset,int whence)55 real_fseek (FILE *file, file_ptr offset, int whence)
56 {
57 #if defined (HAVE_FSEEKO64)
58 return fseeko64 (file, offset, whence);
59 #elif defined (HAVE_FSEEKO)
60 return fseeko (file, offset, whence);
61 #else
62 return fseek (file, offset, whence);
63 #endif
64 }
65
66 FILE *
real_fopen(const char * filename,const char * modes)67 real_fopen (const char *filename, const char *modes)
68 {
69 #if defined (HAVE_FOPEN64)
70 return fopen64 (filename, modes);
71 #else
72 return fopen (filename, modes);
73 #endif
74 }
75
76 /*
77 INTERNAL_DEFINITION
78 struct bfd_iovec
79
80 DESCRIPTION
81
82 The <<struct bfd_iovec>> contains the internal file I/O class.
83 Each <<BFD>> has an instance of this class and all file I/O is
84 routed through it (it is assumed that the instance implements
85 all methods listed below).
86
87 .struct bfd_iovec
88 .{
89 . {* To avoid problems with macros, a "b" rather than "f"
90 . prefix is prepended to each method name. *}
91 . {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
92 . bytes starting at PTR. Return the number of bytes actually
93 . transfered (a read past end-of-file returns less than NBYTES),
94 . or -1 (setting <<bfd_error>>) if an error occurs. *}
95 . file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes);
96 . file_ptr (*bwrite) (struct bfd *abfd, const void *ptr,
97 . file_ptr nbytes);
98 . {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>>
99 . if an error occurs. *}
100 . file_ptr (*btell) (struct bfd *abfd);
101 . {* For the following, on successful completion a value of 0 is returned.
102 . Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *}
103 . int (*bseek) (struct bfd *abfd, file_ptr offset, int whence);
104 . int (*bclose) (struct bfd *abfd);
105 . int (*bflush) (struct bfd *abfd);
106 . int (*bstat) (struct bfd *abfd, struct stat *sb);
107 .};
108
109 */
110
111
112 /* Return value is amount read. */
113
114 bfd_size_type
bfd_bread(void * ptr,bfd_size_type size,bfd * abfd)115 bfd_bread (void *ptr, bfd_size_type size, bfd *abfd)
116 {
117 size_t nread;
118
119 if ((abfd->flags & BFD_IN_MEMORY) != 0)
120 {
121 struct bfd_in_memory *bim;
122 bfd_size_type get;
123
124 bim = abfd->iostream;
125 get = size;
126 if (abfd->where + get > bim->size)
127 {
128 if (bim->size < (bfd_size_type) abfd->where)
129 get = 0;
130 else
131 get = bim->size - abfd->where;
132 bfd_set_error (bfd_error_file_truncated);
133 }
134 memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
135 abfd->where += get;
136 return get;
137 }
138
139 if (abfd->iovec)
140 nread = abfd->iovec->bread (abfd, ptr, size);
141 else
142 nread = 0;
143 if (nread != (size_t) -1)
144 abfd->where += nread;
145
146 return nread;
147 }
148
149 bfd_size_type
bfd_bwrite(const void * ptr,bfd_size_type size,bfd * abfd)150 bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd)
151 {
152 size_t nwrote;
153
154 if ((abfd->flags & BFD_IN_MEMORY) != 0)
155 {
156 struct bfd_in_memory *bim = abfd->iostream;
157
158 size = (size_t) size;
159 if (abfd->where + size > bim->size)
160 {
161 bfd_size_type newsize, oldsize;
162
163 oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
164 bim->size = abfd->where + size;
165 /* Round up to cut down on memory fragmentation */
166 newsize = (bim->size + 127) & ~(bfd_size_type) 127;
167 if (newsize > oldsize)
168 {
169 bim->buffer = bfd_realloc (bim->buffer, newsize);
170 if (bim->buffer == 0)
171 {
172 bim->size = 0;
173 return 0;
174 }
175 }
176 }
177 memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
178 abfd->where += size;
179 return size;
180 }
181
182 if (abfd->iovec)
183 nwrote = abfd->iovec->bwrite (abfd, ptr, size);
184 else
185 nwrote = 0;
186
187 if (nwrote != (size_t) -1)
188 abfd->where += nwrote;
189 if (nwrote != size)
190 {
191 #ifdef ENOSPC
192 errno = ENOSPC;
193 #endif
194 bfd_set_error (bfd_error_system_call);
195 }
196 return nwrote;
197 }
198
199 file_ptr
bfd_tell(bfd * abfd)200 bfd_tell (bfd *abfd)
201 {
202 file_ptr ptr;
203
204 if ((abfd->flags & BFD_IN_MEMORY) != 0)
205 return abfd->where;
206
207 if (abfd->iovec)
208 {
209 ptr = abfd->iovec->btell (abfd);
210
211 if (abfd->my_archive)
212 ptr -= abfd->origin;
213 }
214 else
215 ptr = 0;
216
217 abfd->where = ptr;
218 return ptr;
219 }
220
221 int
bfd_flush(bfd * abfd)222 bfd_flush (bfd *abfd)
223 {
224 if ((abfd->flags & BFD_IN_MEMORY) != 0)
225 return 0;
226
227 if (abfd->iovec)
228 return abfd->iovec->bflush (abfd);
229 return 0;
230 }
231
232 /* Returns 0 for success, negative value for failure (in which case
233 bfd_get_error can retrieve the error code). */
234 int
bfd_stat(bfd * abfd,struct stat * statbuf)235 bfd_stat (bfd *abfd, struct stat *statbuf)
236 {
237 int result;
238
239 if ((abfd->flags & BFD_IN_MEMORY) != 0)
240 abort ();
241
242 if (abfd->iovec)
243 result = abfd->iovec->bstat (abfd, statbuf);
244 else
245 result = -1;
246
247 if (result < 0)
248 bfd_set_error (bfd_error_system_call);
249 return result;
250 }
251
252 /* Returns 0 for success, nonzero for failure (in which case bfd_get_error
253 can retrieve the error code). */
254
255 int
bfd_seek(bfd * abfd,file_ptr position,int direction)256 bfd_seek (bfd *abfd, file_ptr position, int direction)
257 {
258 int result;
259 file_ptr file_position;
260 /* For the time being, a BFD may not seek to it's end. The problem
261 is that we don't easily have a way to recognize the end of an
262 element in an archive. */
263
264 BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR);
265
266 if (direction == SEEK_CUR && position == 0)
267 return 0;
268
269 if ((abfd->flags & BFD_IN_MEMORY) != 0)
270 {
271 struct bfd_in_memory *bim;
272
273 bim = abfd->iostream;
274
275 if (direction == SEEK_SET)
276 abfd->where = position;
277 else
278 abfd->where += position;
279
280 if (abfd->where > bim->size)
281 {
282 if ((abfd->direction == write_direction) ||
283 (abfd->direction == both_direction))
284 {
285 bfd_size_type newsize, oldsize;
286
287 oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
288 bim->size = abfd->where;
289 /* Round up to cut down on memory fragmentation */
290 newsize = (bim->size + 127) & ~(bfd_size_type) 127;
291 if (newsize > oldsize)
292 {
293 bim->buffer = bfd_realloc (bim->buffer, newsize);
294 if (bim->buffer == 0)
295 {
296 bim->size = 0;
297 return -1;
298 }
299 }
300 }
301 else
302 {
303 abfd->where = bim->size;
304 bfd_set_error (bfd_error_file_truncated);
305 return -1;
306 }
307 }
308 return 0;
309 }
310
311 if (abfd->format != bfd_archive && abfd->my_archive == 0)
312 {
313 if (direction == SEEK_SET && (bfd_vma) position == abfd->where)
314 return 0;
315 }
316 else
317 {
318 /* We need something smarter to optimize access to archives.
319 Currently, anything inside an archive is read via the file
320 handle for the archive. Which means that a bfd_seek on one
321 component affects the `current position' in the archive, as
322 well as in any other component.
323
324 It might be sufficient to put a spike through the cache
325 abstraction, and look to the archive for the file position,
326 but I think we should try for something cleaner.
327
328 In the meantime, no optimization for archives. */
329 }
330
331 file_position = position;
332 if (direction == SEEK_SET && abfd->my_archive != NULL)
333 file_position += abfd->origin;
334
335 if (abfd->iovec)
336 result = abfd->iovec->bseek (abfd, file_position, direction);
337 else
338 result = -1;
339
340 if (result != 0)
341 {
342 int hold_errno = errno;
343
344 /* Force redetermination of `where' field. */
345 bfd_tell (abfd);
346
347 /* An EINVAL error probably means that the file offset was
348 absurd. */
349 if (hold_errno == EINVAL)
350 bfd_set_error (bfd_error_file_truncated);
351 else
352 {
353 bfd_set_error (bfd_error_system_call);
354 errno = hold_errno;
355 }
356 }
357 else
358 {
359 /* Adjust `where' field. */
360 if (direction == SEEK_SET)
361 abfd->where = position;
362 else
363 abfd->where += position;
364 }
365 return result;
366 }
367
368 /*
369 FUNCTION
370 bfd_get_mtime
371
372 SYNOPSIS
373 time_t bfd_get_mtime (bfd *abfd);
374
375 DESCRIPTION
376 Return the file modification time (as read from the file system, or
377 from the archive header for archive members).
378
379 */
380
381 time_t
bfd_get_mtime(bfd * abfd)382 bfd_get_mtime (bfd *abfd)
383 {
384 struct stat buf;
385
386 if (abfd->mtime_set)
387 return abfd->mtime;
388
389 if (abfd->iovec == NULL)
390 return 0;
391
392 if (abfd->iovec->bstat (abfd, &buf) != 0)
393 return 0;
394
395 abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */
396 return buf.st_mtime;
397 }
398
399 /*
400 FUNCTION
401 bfd_get_size
402
403 SYNOPSIS
404 long bfd_get_size (bfd *abfd);
405
406 DESCRIPTION
407 Return the file size (as read from file system) for the file
408 associated with BFD @var{abfd}.
409
410 The initial motivation for, and use of, this routine is not
411 so we can get the exact size of the object the BFD applies to, since
412 that might not be generally possible (archive members for example).
413 It would be ideal if someone could eventually modify
414 it so that such results were guaranteed.
415
416 Instead, we want to ask questions like "is this NNN byte sized
417 object I'm about to try read from file offset YYY reasonable?"
418 As as example of where we might do this, some object formats
419 use string tables for which the first <<sizeof (long)>> bytes of the
420 table contain the size of the table itself, including the size bytes.
421 If an application tries to read what it thinks is one of these
422 string tables, without some way to validate the size, and for
423 some reason the size is wrong (byte swapping error, wrong location
424 for the string table, etc.), the only clue is likely to be a read
425 error when it tries to read the table, or a "virtual memory
426 exhausted" error when it tries to allocate 15 bazillon bytes
427 of space for the 15 bazillon byte table it is about to read.
428 This function at least allows us to answer the question, "is the
429 size reasonable?".
430 */
431
432 long
bfd_get_size(bfd * abfd)433 bfd_get_size (bfd *abfd)
434 {
435 struct stat buf;
436
437 if ((abfd->flags & BFD_IN_MEMORY) != 0)
438 return ((struct bfd_in_memory *) abfd->iostream)->size;
439
440 if (abfd->iovec == NULL)
441 return 0;
442
443 if (abfd->iovec->bstat (abfd, &buf) != 0)
444 return 0;
445
446 return buf.st_size;
447 }
448