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93509525 KD |
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. | |
5 | ||
6 | This file is part of BFD, the Binary File Descriptor library. | |
7 | ||
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. | |
12 | ||
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. | |
17 | ||
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. */ | |
21 | ||
22 | #include "sysdep.h" | |
23 | ||
24 | #include "bfd.h" | |
25 | #include "libbfd.h" | |
26 | ||
27 | #include <limits.h> | |
28 | ||
29 | #ifndef S_IXUSR | |
30 | #define S_IXUSR 0100 /* Execute by owner. */ | |
31 | #endif | |
32 | #ifndef S_IXGRP | |
33 | #define S_IXGRP 0010 /* Execute by group. */ | |
34 | #endif | |
35 | #ifndef S_IXOTH | |
36 | #define S_IXOTH 0001 /* Execute by others. */ | |
37 | #endif | |
38 | ||
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. | |
41 | ||
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. */ | |
45 | ||
46 | static size_t real_read PARAMS ((PTR where, size_t a, size_t b, FILE *file)); | |
47 | static size_t | |
48 | real_read (where, a, b, file) | |
49 | PTR where; | |
50 | size_t a; | |
51 | size_t b; | |
52 | FILE *file; | |
53 | { | |
54 | /* FIXME - this looks like an optimization, but it's really to cover | |
55 | up for a feature of some OSs (not solaris - sigh) that | |
56 | ld/pe-dll.c takes advantage of (apparently) when it creates BFDs | |
57 | internally and tries to link against them. BFD seems to be smart | |
58 | enough to realize there are no symbol records in the "file" that | |
59 | doesn't exist but attempts to read them anyway. On Solaris, | |
60 | attempting to read zero bytes from a NULL file results in a core | |
61 | dump, but on other platforms it just returns zero bytes read. | |
62 | This makes it to something reasonable. - DJ */ | |
63 | if (a == 0 || b == 0) | |
64 | return 0; | |
65 | ||
66 | ||
67 | #if defined (__VAX) && defined (VMS) | |
68 | /* Apparently fread on Vax VMS does not keep the record length | |
69 | information. */ | |
70 | return read (fileno (file), where, a * b); | |
71 | #else | |
72 | return fread (where, a, b, file); | |
73 | #endif | |
74 | } | |
75 | ||
76 | /* Return value is amount read. */ | |
77 | ||
78 | bfd_size_type | |
79 | bfd_bread (ptr, size, abfd) | |
80 | PTR ptr; | |
81 | bfd_size_type size; | |
82 | bfd *abfd; | |
83 | { | |
84 | size_t nread; | |
85 | ||
86 | if ((abfd->flags & BFD_IN_MEMORY) != 0) | |
87 | { | |
88 | struct bfd_in_memory *bim; | |
89 | bfd_size_type get; | |
90 | ||
91 | bim = (struct bfd_in_memory *) abfd->iostream; | |
92 | get = size; | |
93 | if (abfd->where + get > bim->size) | |
94 | { | |
95 | if (bim->size < (bfd_size_type) abfd->where) | |
96 | get = 0; | |
97 | else | |
98 | get = bim->size - abfd->where; | |
99 | bfd_set_error (bfd_error_file_truncated); | |
100 | } | |
101 | memcpy (ptr, bim->buffer + abfd->where, (size_t) get); | |
102 | abfd->where += get; | |
103 | return get; | |
104 | } | |
105 | ||
106 | nread = real_read (ptr, 1, (size_t) size, bfd_cache_lookup (abfd)); | |
107 | if (nread != (size_t) -1) | |
108 | abfd->where += nread; | |
109 | ||
110 | /* Set bfd_error if we did not read as much data as we expected. | |
111 | ||
112 | If the read failed due to an error set the bfd_error_system_call, | |
113 | else set bfd_error_file_truncated. | |
114 | ||
115 | A BFD backend may wish to override bfd_error_file_truncated to | |
116 | provide something more useful (eg. no_symbols or wrong_format). */ | |
117 | if (nread != size) | |
118 | { | |
119 | if (ferror (bfd_cache_lookup (abfd))) | |
120 | bfd_set_error (bfd_error_system_call); | |
121 | else | |
122 | bfd_set_error (bfd_error_file_truncated); | |
123 | } | |
124 | ||
125 | return nread; | |
126 | } | |
127 | ||
128 | bfd_size_type | |
129 | bfd_bwrite (ptr, size, abfd) | |
130 | const PTR ptr; | |
131 | bfd_size_type size; | |
132 | bfd *abfd; | |
133 | { | |
134 | size_t nwrote; | |
135 | ||
136 | if ((abfd->flags & BFD_IN_MEMORY) != 0) | |
137 | { | |
138 | struct bfd_in_memory *bim = (struct bfd_in_memory *) (abfd->iostream); | |
139 | size = (size_t) size; | |
140 | if (abfd->where + size > bim->size) | |
141 | { | |
142 | bfd_size_type newsize, oldsize; | |
143 | ||
144 | oldsize = (bim->size + 127) & ~(bfd_size_type) 127; | |
145 | bim->size = abfd->where + size; | |
146 | /* Round up to cut down on memory fragmentation */ | |
147 | newsize = (bim->size + 127) & ~(bfd_size_type) 127; | |
148 | if (newsize > oldsize) | |
149 | { | |
150 | bim->buffer = (bfd_byte *) bfd_realloc (bim->buffer, newsize); | |
151 | if (bim->buffer == 0) | |
152 | { | |
153 | bim->size = 0; | |
154 | return 0; | |
155 | } | |
156 | } | |
157 | } | |
158 | memcpy (bim->buffer + abfd->where, ptr, (size_t) size); | |
159 | abfd->where += size; | |
160 | return size; | |
161 | } | |
162 | ||
163 | nwrote = fwrite (ptr, 1, (size_t) size, bfd_cache_lookup (abfd)); | |
164 | if (nwrote != (size_t) -1) | |
165 | abfd->where += nwrote; | |
166 | if (nwrote != size) | |
167 | { | |
168 | #ifdef ENOSPC | |
169 | errno = ENOSPC; | |
170 | #endif | |
171 | bfd_set_error (bfd_error_system_call); | |
172 | } | |
173 | return nwrote; | |
174 | } | |
175 | ||
176 | bfd_vma | |
177 | bfd_tell (abfd) | |
178 | bfd *abfd; | |
179 | { | |
180 | file_ptr ptr; | |
181 | ||
182 | if ((abfd->flags & BFD_IN_MEMORY) != 0) | |
183 | return abfd->where; | |
184 | ||
185 | ptr = ftell (bfd_cache_lookup (abfd)); | |
186 | ||
187 | if (abfd->my_archive) | |
188 | ptr -= abfd->origin; | |
189 | abfd->where = ptr; | |
190 | return ptr; | |
191 | } | |
192 | ||
193 | int | |
194 | bfd_flush (abfd) | |
195 | bfd *abfd; | |
196 | { | |
197 | if ((abfd->flags & BFD_IN_MEMORY) != 0) | |
198 | return 0; | |
199 | return fflush (bfd_cache_lookup(abfd)); | |
200 | } | |
201 | ||
202 | /* Returns 0 for success, negative value for failure (in which case | |
203 | bfd_get_error can retrieve the error code). */ | |
204 | int | |
205 | bfd_stat (abfd, statbuf) | |
206 | bfd *abfd; | |
207 | struct stat *statbuf; | |
208 | { | |
209 | FILE *f; | |
210 | int result; | |
211 | ||
212 | if ((abfd->flags & BFD_IN_MEMORY) != 0) | |
213 | abort (); | |
214 | ||
215 | f = bfd_cache_lookup (abfd); | |
216 | if (f == NULL) | |
217 | { | |
218 | bfd_set_error (bfd_error_system_call); | |
219 | return -1; | |
220 | } | |
221 | result = fstat (fileno (f), statbuf); | |
222 | if (result < 0) | |
223 | bfd_set_error (bfd_error_system_call); | |
224 | return result; | |
225 | } | |
226 | ||
227 | /* Returns 0 for success, nonzero for failure (in which case bfd_get_error | |
228 | can retrieve the error code). */ | |
229 | ||
230 | int | |
231 | bfd_seek (abfd, position, direction) | |
232 | bfd *abfd; | |
233 | file_ptr position; | |
234 | int direction; | |
235 | { | |
236 | int result; | |
237 | FILE *f; | |
238 | long file_position; | |
239 | /* For the time being, a BFD may not seek to it's end. The problem | |
240 | is that we don't easily have a way to recognize the end of an | |
241 | element in an archive. */ | |
242 | ||
243 | BFD_ASSERT (direction == SEEK_SET || direction == SEEK_CUR); | |
244 | ||
245 | if (direction == SEEK_CUR && position == 0) | |
246 | return 0; | |
247 | ||
248 | if ((abfd->flags & BFD_IN_MEMORY) != 0) | |
249 | { | |
250 | struct bfd_in_memory *bim; | |
251 | ||
252 | bim = (struct bfd_in_memory *) abfd->iostream; | |
253 | ||
254 | if (direction == SEEK_SET) | |
255 | abfd->where = position; | |
256 | else | |
257 | abfd->where += position; | |
258 | ||
259 | if (abfd->where > bim->size) | |
260 | { | |
261 | if ((abfd->direction == write_direction) || | |
262 | (abfd->direction == both_direction)) | |
263 | { | |
264 | bfd_size_type newsize, oldsize; | |
265 | oldsize = (bim->size + 127) & ~(bfd_size_type) 127; | |
266 | bim->size = abfd->where; | |
267 | /* Round up to cut down on memory fragmentation */ | |
268 | newsize = (bim->size + 127) & ~(bfd_size_type) 127; | |
269 | if (newsize > oldsize) | |
270 | { | |
271 | bim->buffer = (bfd_byte *) bfd_realloc (bim->buffer, newsize); | |
272 | if (bim->buffer == 0) | |
273 | { | |
274 | bim->size = 0; | |
275 | return -1; | |
276 | } | |
277 | } | |
278 | } | |
279 | else | |
280 | { | |
281 | abfd->where = bim->size; | |
282 | bfd_set_error (bfd_error_file_truncated); | |
283 | return -1; | |
284 | } | |
285 | } | |
286 | return 0; | |
287 | } | |
288 | ||
289 | if (abfd->format != bfd_archive && abfd->my_archive == 0) | |
290 | { | |
291 | #if 0 | |
292 | /* Explanation for this code: I'm only about 95+% sure that the above | |
293 | conditions are sufficient and that all i/o calls are properly | |
294 | adjusting the `where' field. So this is sort of an `assert' | |
295 | that the `where' field is correct. If we can go a while without | |
296 | tripping the abort, we can probably safely disable this code, | |
297 | so that the real optimizations happen. */ | |
298 | file_ptr where_am_i_now; | |
299 | where_am_i_now = ftell (bfd_cache_lookup (abfd)); | |
300 | if (abfd->my_archive) | |
301 | where_am_i_now -= abfd->origin; | |
302 | if (where_am_i_now != abfd->where) | |
303 | abort (); | |
304 | #endif | |
305 | if (direction == SEEK_SET && (bfd_vma) position == abfd->where) | |
306 | return 0; | |
307 | } | |
308 | else | |
309 | { | |
310 | /* We need something smarter to optimize access to archives. | |
311 | Currently, anything inside an archive is read via the file | |
312 | handle for the archive. Which means that a bfd_seek on one | |
313 | component affects the `current position' in the archive, as | |
314 | well as in any other component. | |
315 | ||
316 | It might be sufficient to put a spike through the cache | |
317 | abstraction, and look to the archive for the file position, | |
318 | but I think we should try for something cleaner. | |
319 | ||
320 | In the meantime, no optimization for archives. */ | |
321 | } | |
322 | ||
323 | f = bfd_cache_lookup (abfd); | |
324 | file_position = position; | |
325 | if (direction == SEEK_SET && abfd->my_archive != NULL) | |
326 | file_position += abfd->origin; | |
327 | ||
328 | result = fseek (f, file_position, direction); | |
329 | if (result != 0) | |
330 | { | |
331 | int hold_errno = errno; | |
332 | ||
333 | /* Force redetermination of `where' field. */ | |
334 | bfd_tell (abfd); | |
335 | ||
336 | /* An EINVAL error probably means that the file offset was | |
337 | absurd. */ | |
338 | if (hold_errno == EINVAL) | |
339 | bfd_set_error (bfd_error_file_truncated); | |
340 | else | |
341 | { | |
342 | bfd_set_error (bfd_error_system_call); | |
343 | errno = hold_errno; | |
344 | } | |
345 | } | |
346 | else | |
347 | { | |
348 | /* Adjust `where' field. */ | |
349 | if (direction == SEEK_SET) | |
350 | abfd->where = position; | |
351 | else | |
352 | abfd->where += position; | |
353 | } | |
354 | return result; | |
355 | } | |
356 | ||
357 | /* | |
358 | FUNCTION | |
359 | bfd_get_mtime | |
360 | ||
361 | SYNOPSIS | |
362 | long bfd_get_mtime(bfd *abfd); | |
363 | ||
364 | DESCRIPTION | |
365 | Return the file modification time (as read from the file system, or | |
366 | from the archive header for archive members). | |
367 | ||
368 | */ | |
369 | ||
370 | long | |
371 | bfd_get_mtime (abfd) | |
372 | bfd *abfd; | |
373 | { | |
374 | FILE *fp; | |
375 | struct stat buf; | |
376 | ||
377 | if (abfd->mtime_set) | |
378 | return abfd->mtime; | |
379 | ||
380 | fp = bfd_cache_lookup (abfd); | |
381 | if (0 != fstat (fileno (fp), &buf)) | |
382 | return 0; | |
383 | ||
384 | abfd->mtime = buf.st_mtime; /* Save value in case anyone wants it */ | |
385 | return buf.st_mtime; | |
386 | } | |
387 | ||
388 | /* | |
389 | FUNCTION | |
390 | bfd_get_size | |
391 | ||
392 | SYNOPSIS | |
393 | long bfd_get_size(bfd *abfd); | |
394 | ||
395 | DESCRIPTION | |
396 | Return the file size (as read from file system) for the file | |
397 | associated with BFD @var{abfd}. | |
398 | ||
399 | The initial motivation for, and use of, this routine is not | |
400 | so we can get the exact size of the object the BFD applies to, since | |
401 | that might not be generally possible (archive members for example). | |
402 | It would be ideal if someone could eventually modify | |
403 | it so that such results were guaranteed. | |
404 | ||
405 | Instead, we want to ask questions like "is this NNN byte sized | |
406 | object I'm about to try read from file offset YYY reasonable?" | |
407 | As as example of where we might do this, some object formats | |
408 | use string tables for which the first <<sizeof (long)>> bytes of the | |
409 | table contain the size of the table itself, including the size bytes. | |
410 | If an application tries to read what it thinks is one of these | |
411 | string tables, without some way to validate the size, and for | |
412 | some reason the size is wrong (byte swapping error, wrong location | |
413 | for the string table, etc.), the only clue is likely to be a read | |
414 | error when it tries to read the table, or a "virtual memory | |
415 | exhausted" error when it tries to allocate 15 bazillon bytes | |
416 | of space for the 15 bazillon byte table it is about to read. | |
417 | This function at least allows us to answer the quesion, "is the | |
418 | size reasonable?". | |
419 | */ | |
420 | ||
421 | long | |
422 | bfd_get_size (abfd) | |
423 | bfd *abfd; | |
424 | { | |
425 | FILE *fp; | |
426 | struct stat buf; | |
427 | ||
428 | if ((abfd->flags & BFD_IN_MEMORY) != 0) | |
429 | return ((struct bfd_in_memory *) abfd->iostream)->size; | |
430 | ||
431 | fp = bfd_cache_lookup (abfd); | |
432 | if (0 != fstat (fileno (fp), & buf)) | |
433 | return 0; | |
434 | ||
435 | return buf.st_size; | |
436 | } |