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, 2006, 2007
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 #include <limits.h>
27 #include "bfd.h"
28 #include "libbfd.h"
29
30 #ifndef S_IXUSR
31 #define S_IXUSR 0100 /* Execute by owner. */
32 #endif
33 #ifndef S_IXGRP
34 #define S_IXGRP 0010 /* Execute by group. */
35 #endif
36 #ifndef S_IXOTH
37 #define S_IXOTH 0001 /* Execute by others. */
38 #endif
39
40 file_ptr
real_ftell(FILE * file)41 real_ftell (FILE *file)
42 {
43 #if defined (HAVE_FTELLO64)
44 return ftello64 (file);
45 #elif defined (HAVE_FTELLO)
46 return ftello (file);
47 #else
48 return ftell (file);
49 #endif
50 }
51
52 int
real_fseek(FILE * file,file_ptr offset,int whence)53 real_fseek (FILE *file, file_ptr offset, int whence)
54 {
55 #if defined (HAVE_FSEEKO64)
56 return fseeko64 (file, offset, whence);
57 #elif defined (HAVE_FSEEKO)
58 return fseeko (file, offset, whence);
59 #else
60 return fseek (file, offset, whence);
61 #endif
62 }
63
64 FILE *
real_fopen(const char * filename,const char * modes)65 real_fopen (const char *filename, const char *modes)
66 {
67 #if defined (HAVE_FOPEN64)
68 return fopen64 (filename, modes);
69 #else
70 return fopen (filename, modes);
71 #endif
72 }
73
74 /*
75 INTERNAL_DEFINITION
76 struct bfd_iovec
77
78 DESCRIPTION
79
80 The <<struct bfd_iovec>> contains the internal file I/O class.
81 Each <<BFD>> has an instance of this class and all file I/O is
82 routed through it (it is assumed that the instance implements
83 all methods listed below).
84
85 .struct bfd_iovec
86 .{
87 . {* To avoid problems with macros, a "b" rather than "f"
88 . prefix is prepended to each method name. *}
89 . {* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
90 . bytes starting at PTR. Return the number of bytes actually
91 . transfered (a read past end-of-file returns less than NBYTES),
92 . or -1 (setting <<bfd_error>>) if an error occurs. *}
93 . file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes);
94 . file_ptr (*bwrite) (struct bfd *abfd, const void *ptr,
95 . file_ptr nbytes);
96 . {* Return the current IOSTREAM file offset, or -1 (setting <<bfd_error>>
97 . if an error occurs. *}
98 . file_ptr (*btell) (struct bfd *abfd);
99 . {* For the following, on successful completion a value of 0 is returned.
100 . Otherwise, a value of -1 is returned (and <<bfd_error>> is set). *}
101 . int (*bseek) (struct bfd *abfd, file_ptr offset, int whence);
102 . int (*bclose) (struct bfd *abfd);
103 . int (*bflush) (struct bfd *abfd);
104 . int (*bstat) (struct bfd *abfd, struct stat *sb);
105 .};
106
107 */
108
109
110 /* Return value is amount read. */
111
112 bfd_size_type
bfd_bread(void * ptr,bfd_size_type size,bfd * abfd)113 bfd_bread (void *ptr, bfd_size_type size, bfd *abfd)
114 {
115 size_t nread;
116
117 /* If this is an archive element, don't read past the end of
118 this element. */
119 if (abfd->arelt_data != NULL)
120 {
121 size_t maxbytes = ((struct areltdata *) abfd->arelt_data)->parsed_size;
122 if (size > maxbytes)
123 size = maxbytes;
124 }
125
126 if ((abfd->flags & BFD_IN_MEMORY) != 0)
127 {
128 struct bfd_in_memory *bim;
129 bfd_size_type get;
130
131 bim = abfd->iostream;
132 get = size;
133 if (abfd->where + get > bim->size)
134 {
135 if (bim->size < (bfd_size_type) abfd->where)
136 get = 0;
137 else
138 get = bim->size - abfd->where;
139 bfd_set_error (bfd_error_file_truncated);
140 }
141 memcpy (ptr, bim->buffer + abfd->where, (size_t) get);
142 abfd->where += get;
143 return get;
144 }
145
146 if (abfd->iovec)
147 nread = abfd->iovec->bread (abfd, ptr, size);
148 else
149 nread = 0;
150 if (nread != (size_t) -1)
151 abfd->where += nread;
152
153 return nread;
154 }
155
156 bfd_size_type
bfd_bwrite(const void * ptr,bfd_size_type size,bfd * abfd)157 bfd_bwrite (const void *ptr, bfd_size_type size, bfd *abfd)
158 {
159 size_t nwrote;
160
161 if ((abfd->flags & BFD_IN_MEMORY) != 0)
162 {
163 struct bfd_in_memory *bim = abfd->iostream;
164
165 size = (size_t) size;
166 if (abfd->where + size > bim->size)
167 {
168 bfd_size_type newsize, oldsize;
169
170 oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
171 bim->size = abfd->where + size;
172 /* Round up to cut down on memory fragmentation */
173 newsize = (bim->size + 127) & ~(bfd_size_type) 127;
174 if (newsize > oldsize)
175 {
176 bim->buffer = bfd_realloc (bim->buffer, newsize);
177 if (bim->buffer == 0)
178 {
179 bim->size = 0;
180 return 0;
181 }
182 }
183 }
184 memcpy (bim->buffer + abfd->where, ptr, (size_t) size);
185 abfd->where += size;
186 return size;
187 }
188
189 if (abfd->iovec)
190 nwrote = abfd->iovec->bwrite (abfd, ptr, size);
191 else
192 nwrote = 0;
193
194 if (nwrote != (size_t) -1)
195 abfd->where += nwrote;
196 if (nwrote != size)
197 {
198 #ifdef ENOSPC
199 errno = ENOSPC;
200 #endif
201 bfd_set_error (bfd_error_system_call);
202 }
203 return nwrote;
204 }
205
206 file_ptr
bfd_tell(bfd * abfd)207 bfd_tell (bfd *abfd)
208 {
209 file_ptr ptr;
210
211 if ((abfd->flags & BFD_IN_MEMORY) != 0)
212 return abfd->where;
213
214 if (abfd->iovec)
215 {
216 ptr = abfd->iovec->btell (abfd);
217
218 if (abfd->my_archive)
219 ptr -= abfd->origin;
220 }
221 else
222 ptr = 0;
223
224 abfd->where = ptr;
225 return ptr;
226 }
227
228 int
bfd_flush(bfd * abfd)229 bfd_flush (bfd *abfd)
230 {
231 if ((abfd->flags & BFD_IN_MEMORY) != 0)
232 return 0;
233
234 if (abfd->iovec)
235 return abfd->iovec->bflush (abfd);
236 return 0;
237 }
238
239 /* Returns 0 for success, negative value for failure (in which case
240 bfd_get_error can retrieve the error code). */
241 int
bfd_stat(bfd * abfd,struct stat * statbuf)242 bfd_stat (bfd *abfd, struct stat *statbuf)
243 {
244 int result;
245
246 if ((abfd->flags & BFD_IN_MEMORY) != 0)
247 abort ();
248
249 if (abfd->iovec)
250 result = abfd->iovec->bstat (abfd, statbuf);
251 else
252 result = -1;
253
254 if (result < 0)
255 bfd_set_error (bfd_error_system_call);
256 return result;
257 }
258
259 /* Returns 0 for success, nonzero for failure (in which case bfd_get_error
260 can retrieve the error code). */
261
262 int
bfd_seek(bfd * abfd,file_ptr position,int direction)263 bfd_seek (bfd *abfd, file_ptr position, int direction)
264 {
265 int result;
266 file_ptr file_position;
267 /* For the time being, a BFD may not seek to it's end. The problem
268 is that we don't easily have a way to recognize the end of an
269 element in an archive. */
270
271 BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR);
272
273 if (direction == SEEK_CUR && position == 0)
274 return 0;
275
276 if ((abfd->flags & BFD_IN_MEMORY) != 0)
277 {
278 struct bfd_in_memory *bim;
279
280 bim = abfd->iostream;
281
282 if (direction == SEEK_SET)
283 abfd->where = position;
284 else
285 abfd->where += position;
286
287 if (abfd->where > bim->size)
288 {
289 if ((abfd->direction == write_direction) ||
290 (abfd->direction == both_direction))
291 {
292 bfd_size_type newsize, oldsize;
293
294 oldsize = (bim->size + 127) & ~(bfd_size_type) 127;
295 bim->size = abfd->where;
296 /* Round up to cut down on memory fragmentation */
297 newsize = (bim->size + 127) & ~(bfd_size_type) 127;
298 if (newsize > oldsize)
299 {
300 bim->buffer = bfd_realloc (bim->buffer, newsize);
301 if (bim->buffer == 0)
302 {
303 bim->size = 0;
304 return -1;
305 }
306 }
307 }
308 else
309 {
310 abfd->where = bim->size;
311 bfd_set_error (bfd_error_file_truncated);
312 return -1;
313 }
314 }
315 return 0;
316 }
317
318 if (abfd->format != bfd_archive && abfd->my_archive == 0)
319 {
320 if (direction == SEEK_SET && (bfd_vma) position == abfd->where)
321 return 0;
322 }
323 else
324 {
325 /* We need something smarter to optimize access to archives.
326 Currently, anything inside an archive is read via the file
327 handle for the archive. Which means that a bfd_seek on one
328 component affects the `current position' in the archive, as
329 well as in any other component.
330
331 It might be sufficient to put a spike through the cache
332 abstraction, and look to the archive for the file position,
333 but I think we should try for something cleaner.
334
335 In the meantime, no optimization for archives. */
336 }
337
338 file_position = position;
339 if (direction == SEEK_SET && abfd->my_archive != NULL)
340 file_position += abfd->origin;
341
342 if (abfd->iovec)
343 result = abfd->iovec->bseek (abfd, file_position, direction);
344 else
345 result = -1;
346
347 if (result != 0)
348 {
349 int hold_errno = errno;
350
351 /* Force redetermination of `where' field. */
352 bfd_tell (abfd);
353
354 /* An EINVAL error probably means that the file offset was
355 absurd. */
356 if (hold_errno == EINVAL)
357 bfd_set_error (bfd_error_file_truncated);
358 else
359 {
360 bfd_set_error (bfd_error_system_call);
361 errno = hold_errno;
362 }
363 }
364 else
365 {
366 /* Adjust `where' field. */
367 if (direction == SEEK_SET)
368 abfd->where = position;
369 else
370 abfd->where += position;
371 }
372 return result;
373 }
374
375 /*
376 FUNCTION
377 bfd_get_mtime
378
379 SYNOPSIS
380 long bfd_get_mtime (bfd *abfd);
381
382 DESCRIPTION
383 Return the file modification time (as read from the file system, or
384 from the archive header for archive members).
385
386 */
387
388 long
bfd_get_mtime(bfd * abfd)389 bfd_get_mtime (bfd *abfd)
390 {
391 struct stat buf;
392
393 if (abfd->mtime_set)
394 return abfd->mtime;
395
396 if (abfd->iovec == NULL)
397 return 0;
398
399 if (abfd->iovec->bstat (abfd, &buf) != 0)
400 return 0;
401
402 abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */
403 return buf.st_mtime;
404 }
405
406 /*
407 FUNCTION
408 bfd_get_size
409
410 SYNOPSIS
411 file_ptr bfd_get_size (bfd *abfd);
412
413 DESCRIPTION
414 Return the file size (as read from file system) for the file
415 associated with BFD @var{abfd}.
416
417 The initial motivation for, and use of, this routine is not
418 so we can get the exact size of the object the BFD applies to, since
419 that might not be generally possible (archive members for example).
420 It would be ideal if someone could eventually modify
421 it so that such results were guaranteed.
422
423 Instead, we want to ask questions like "is this NNN byte sized
424 object I'm about to try read from file offset YYY reasonable?"
425 As as example of where we might do this, some object formats
426 use string tables for which the first <<sizeof (long)>> bytes of the
427 table contain the size of the table itself, including the size bytes.
428 If an application tries to read what it thinks is one of these
429 string tables, without some way to validate the size, and for
430 some reason the size is wrong (byte swapping error, wrong location
431 for the string table, etc.), the only clue is likely to be a read
432 error when it tries to read the table, or a "virtual memory
433 exhausted" error when it tries to allocate 15 bazillon bytes
434 of space for the 15 bazillon byte table it is about to read.
435 This function at least allows us to answer the question, "is the
436 size reasonable?".
437 */
438
439 file_ptr
bfd_get_size(bfd * abfd)440 bfd_get_size (bfd *abfd)
441 {
442 struct stat buf;
443
444 if ((abfd->flags & BFD_IN_MEMORY) != 0)
445 return ((struct bfd_in_memory *) abfd->iostream)->size;
446
447 if (abfd->iovec == NULL)
448 return 0;
449
450 if (abfd->iovec->bstat (abfd, &buf) != 0)
451 return 0;
452
453 return buf.st_size;
454 }
455