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