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1 | /** |
2 | * attrib.c - NTFS attribute operations. Part of the Linux-NTFS project. | |
3 | * | |
4 | * Copyright (c) 2001-2004 Anton Altaparmakov | |
5 | * Copyright (c) 2002 Richard Russon | |
6 | * | |
7 | * This program/include file is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License as published | |
9 | * by the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program/include file is distributed in the hope that it will be | |
13 | * useful, but WITHOUT ANY WARRANTY; without even the implied warranty | |
14 | * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program (in the main directory of the Linux-NTFS | |
19 | * distribution in the file COPYING); if not, write to the Free Software | |
20 | * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
21 | */ | |
22 | ||
23 | #include <linux/buffer_head.h> | |
24 | ||
25 | #include "attrib.h" | |
26 | #include "debug.h" | |
27 | #include "layout.h" | |
28 | #include "mft.h" | |
29 | #include "ntfs.h" | |
30 | #include "types.h" | |
31 | ||
32 | /** | |
33 | * ntfs_map_runlist - map (a part of) a runlist of an ntfs inode | |
34 | * @ni: ntfs inode for which to map (part of) a runlist | |
35 | * @vcn: map runlist part containing this vcn | |
36 | * | |
37 | * Map the part of a runlist containing the @vcn of the ntfs inode @ni. | |
38 | * | |
39 | * Return 0 on success and -errno on error. | |
40 | * | |
41 | * Locking: - The runlist must be unlocked on entry and is unlocked on return. | |
42 | * - This function takes the lock for writing and modifies the runlist. | |
43 | */ | |
44 | int ntfs_map_runlist(ntfs_inode *ni, VCN vcn) | |
45 | { | |
46 | ntfs_inode *base_ni; | |
47 | ntfs_attr_search_ctx *ctx; | |
48 | MFT_RECORD *mrec; | |
49 | int err = 0; | |
50 | ||
51 | ntfs_debug("Mapping runlist part containing vcn 0x%llx.", | |
52 | (unsigned long long)vcn); | |
53 | ||
54 | if (!NInoAttr(ni)) | |
55 | base_ni = ni; | |
56 | else | |
57 | base_ni = ni->ext.base_ntfs_ino; | |
58 | ||
59 | mrec = map_mft_record(base_ni); | |
60 | if (IS_ERR(mrec)) | |
61 | return PTR_ERR(mrec); | |
62 | ctx = ntfs_attr_get_search_ctx(base_ni, mrec); | |
63 | if (unlikely(!ctx)) { | |
64 | err = -ENOMEM; | |
65 | goto err_out; | |
66 | } | |
67 | err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len, | |
68 | CASE_SENSITIVE, vcn, NULL, 0, ctx); | |
69 | if (unlikely(err)) | |
70 | goto put_err_out; | |
71 | ||
72 | down_write(&ni->runlist.lock); | |
73 | /* Make sure someone else didn't do the work while we were sleeping. */ | |
74 | if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <= | |
75 | LCN_RL_NOT_MAPPED)) { | |
76 | runlist_element *rl; | |
77 | ||
78 | rl = ntfs_mapping_pairs_decompress(ni->vol, ctx->attr, | |
79 | ni->runlist.rl); | |
80 | if (IS_ERR(rl)) | |
81 | err = PTR_ERR(rl); | |
82 | else | |
83 | ni->runlist.rl = rl; | |
84 | } | |
85 | up_write(&ni->runlist.lock); | |
86 | ||
87 | put_err_out: | |
88 | ntfs_attr_put_search_ctx(ctx); | |
89 | err_out: | |
90 | unmap_mft_record(base_ni); | |
91 | return err; | |
92 | } | |
93 | ||
94 | /** | |
95 | * ntfs_find_vcn - find a vcn in the runlist described by an ntfs inode | |
96 | * @ni: ntfs inode describing the runlist to search | |
97 | * @vcn: vcn to find | |
98 | * @need_write: if false, lock for reading and if true, lock for writing | |
99 | * | |
100 | * Find the virtual cluster number @vcn in the runlist described by the ntfs | |
101 | * inode @ni and return the address of the runlist element containing the @vcn. | |
102 | * The runlist is left locked and the caller has to unlock it. If @need_write | |
103 | * is true, the runlist is locked for writing and if @need_write is false, the | |
104 | * runlist is locked for reading. In the error case, the runlist is not left | |
105 | * locked. | |
106 | * | |
107 | * Note you need to distinguish between the lcn of the returned runlist element | |
108 | * being >= 0 and LCN_HOLE. In the later case you have to return zeroes on | |
109 | * read and allocate clusters on write. | |
110 | * | |
111 | * Return the runlist element containing the @vcn on success and | |
112 | * ERR_PTR(-errno) on error. You need to test the return value with IS_ERR() | |
113 | * to decide if the return is success or failure and PTR_ERR() to get to the | |
114 | * error code if IS_ERR() is true. | |
115 | * | |
116 | * The possible error return codes are: | |
117 | * -ENOENT - No such vcn in the runlist, i.e. @vcn is out of bounds. | |
118 | * -ENOMEM - Not enough memory to map runlist. | |
119 | * -EIO - Critical error (runlist/file is corrupt, i/o error, etc). | |
120 | * | |
121 | * Locking: - The runlist must be unlocked on entry. | |
122 | * - On failing return, the runlist is unlocked. | |
123 | * - On successful return, the runlist is locked. If @need_write us | |
124 | * true, it is locked for writing. Otherwise is is locked for | |
125 | * reading. | |
126 | */ | |
127 | runlist_element *ntfs_find_vcn(ntfs_inode *ni, const VCN vcn, | |
128 | const BOOL need_write) | |
129 | { | |
130 | runlist_element *rl; | |
131 | int err = 0; | |
132 | BOOL is_retry = FALSE; | |
133 | ||
134 | ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, lock for %sing.", | |
135 | ni->mft_no, (unsigned long long)vcn, | |
136 | !need_write ? "read" : "writ"); | |
137 | BUG_ON(!ni); | |
138 | BUG_ON(!NInoNonResident(ni)); | |
139 | BUG_ON(vcn < 0); | |
140 | lock_retry_remap: | |
141 | if (!need_write) | |
142 | down_read(&ni->runlist.lock); | |
143 | else | |
144 | down_write(&ni->runlist.lock); | |
145 | rl = ni->runlist.rl; | |
146 | if (likely(rl && vcn >= rl[0].vcn)) { | |
147 | while (likely(rl->length)) { | |
148 | if (likely(vcn < rl[1].vcn)) { | |
149 | if (likely(rl->lcn >= LCN_HOLE)) { | |
150 | ntfs_debug("Done."); | |
151 | return rl; | |
152 | } | |
153 | break; | |
154 | } | |
155 | rl++; | |
156 | } | |
157 | if (likely(rl->lcn != LCN_RL_NOT_MAPPED)) { | |
158 | if (likely(rl->lcn == LCN_ENOENT)) | |
159 | err = -ENOENT; | |
160 | else | |
161 | err = -EIO; | |
162 | } | |
163 | } | |
164 | if (!need_write) | |
165 | up_read(&ni->runlist.lock); | |
166 | else | |
167 | up_write(&ni->runlist.lock); | |
168 | if (!err && !is_retry) { | |
169 | /* | |
170 | * The @vcn is in an unmapped region, map the runlist and | |
171 | * retry. | |
172 | */ | |
173 | err = ntfs_map_runlist(ni, vcn); | |
174 | if (likely(!err)) { | |
175 | is_retry = TRUE; | |
176 | goto lock_retry_remap; | |
177 | } | |
178 | /* | |
179 | * -EINVAL and -ENOENT coming from a failed mapping attempt are | |
180 | * equivalent to i/o errors for us as they should not happen in | |
181 | * our code paths. | |
182 | */ | |
183 | if (err == -EINVAL || err == -ENOENT) | |
184 | err = -EIO; | |
185 | } else if (!err) | |
186 | err = -EIO; | |
187 | ntfs_error(ni->vol->sb, "Failed with error code %i.", err); | |
188 | return ERR_PTR(err); | |
189 | } | |
190 | ||
191 | /** | |
192 | * ntfs_attr_find - find (next) attribute in mft record | |
193 | * @type: attribute type to find | |
194 | * @name: attribute name to find (optional, i.e. NULL means don't care) | |
195 | * @name_len: attribute name length (only needed if @name present) | |
196 | * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present) | |
197 | * @val: attribute value to find (optional, resident attributes only) | |
198 | * @val_len: attribute value length | |
199 | * @ctx: search context with mft record and attribute to search from | |
200 | * | |
201 | * You should not need to call this function directly. Use ntfs_attr_lookup() | |
202 | * instead. | |
203 | * | |
204 | * ntfs_attr_find() takes a search context @ctx as parameter and searches the | |
205 | * mft record specified by @ctx->mrec, beginning at @ctx->attr, for an | |
206 | * attribute of @type, optionally @name and @val. | |
207 | * | |
208 | * If the attribute is found, ntfs_attr_find() returns 0 and @ctx->attr will | |
209 | * point to the found attribute. | |
210 | * | |
211 | * If the attribute is not found, ntfs_attr_find() returns -ENOENT and | |
212 | * @ctx->attr will point to the attribute before which the attribute being | |
213 | * searched for would need to be inserted if such an action were to be desired. | |
214 | * | |
215 | * On actual error, ntfs_attr_find() returns -EIO. In this case @ctx->attr is | |
216 | * undefined and in particular do not rely on it not changing. | |
217 | * | |
218 | * If @ctx->is_first is TRUE, the search begins with @ctx->attr itself. If it | |
219 | * is FALSE, the search begins after @ctx->attr. | |
220 | * | |
221 | * If @ic is IGNORE_CASE, the @name comparisson is not case sensitive and | |
222 | * @ctx->ntfs_ino must be set to the ntfs inode to which the mft record | |
223 | * @ctx->mrec belongs. This is so we can get at the ntfs volume and hence at | |
224 | * the upcase table. If @ic is CASE_SENSITIVE, the comparison is case | |
225 | * sensitive. When @name is present, @name_len is the @name length in Unicode | |
226 | * characters. | |
227 | * | |
228 | * If @name is not present (NULL), we assume that the unnamed attribute is | |
229 | * being searched for. | |
230 | * | |
231 | * Finally, the resident attribute value @val is looked for, if present. If | |
232 | * @val is not present (NULL), @val_len is ignored. | |
233 | * | |
234 | * ntfs_attr_find() only searches the specified mft record and it ignores the | |
235 | * presence of an attribute list attribute (unless it is the one being searched | |
236 | * for, obviously). If you need to take attribute lists into consideration, | |
237 | * use ntfs_attr_lookup() instead (see below). This also means that you cannot | |
238 | * use ntfs_attr_find() to search for extent records of non-resident | |
239 | * attributes, as extents with lowest_vcn != 0 are usually described by the | |
240 | * attribute list attribute only. - Note that it is possible that the first | |
241 | * extent is only in the attribute list while the last extent is in the base | |
242 | * mft record, so do not rely on being able to find the first extent in the | |
243 | * base mft record. | |
244 | * | |
245 | * Warning: Never use @val when looking for attribute types which can be | |
246 | * non-resident as this most likely will result in a crash! | |
247 | */ | |
248 | static int ntfs_attr_find(const ATTR_TYPE type, const ntfschar *name, | |
249 | const u32 name_len, const IGNORE_CASE_BOOL ic, | |
250 | const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx) | |
251 | { | |
252 | ATTR_RECORD *a; | |
253 | ntfs_volume *vol = ctx->ntfs_ino->vol; | |
254 | ntfschar *upcase = vol->upcase; | |
255 | u32 upcase_len = vol->upcase_len; | |
256 | ||
257 | /* | |
258 | * Iterate over attributes in mft record starting at @ctx->attr, or the | |
259 | * attribute following that, if @ctx->is_first is TRUE. | |
260 | */ | |
261 | if (ctx->is_first) { | |
262 | a = ctx->attr; | |
263 | ctx->is_first = FALSE; | |
264 | } else | |
265 | a = (ATTR_RECORD*)((u8*)ctx->attr + | |
266 | le32_to_cpu(ctx->attr->length)); | |
267 | for (;; a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) { | |
268 | if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec + | |
269 | le32_to_cpu(ctx->mrec->bytes_allocated)) | |
270 | break; | |
271 | ctx->attr = a; | |
272 | if (unlikely(le32_to_cpu(a->type) > le32_to_cpu(type) || | |
273 | a->type == AT_END)) | |
274 | return -ENOENT; | |
275 | if (unlikely(!a->length)) | |
276 | break; | |
277 | if (a->type != type) | |
278 | continue; | |
279 | /* | |
280 | * If @name is present, compare the two names. If @name is | |
281 | * missing, assume we want an unnamed attribute. | |
282 | */ | |
283 | if (!name) { | |
284 | /* The search failed if the found attribute is named. */ | |
285 | if (a->name_length) | |
286 | return -ENOENT; | |
287 | } else if (!ntfs_are_names_equal(name, name_len, | |
288 | (ntfschar*)((u8*)a + le16_to_cpu(a->name_offset)), | |
289 | a->name_length, ic, upcase, upcase_len)) { | |
290 | register int rc; | |
291 | ||
292 | rc = ntfs_collate_names(name, name_len, | |
293 | (ntfschar*)((u8*)a + | |
294 | le16_to_cpu(a->name_offset)), | |
295 | a->name_length, 1, IGNORE_CASE, | |
296 | upcase, upcase_len); | |
297 | /* | |
298 | * If @name collates before a->name, there is no | |
299 | * matching attribute. | |
300 | */ | |
301 | if (rc == -1) | |
302 | return -ENOENT; | |
303 | /* If the strings are not equal, continue search. */ | |
304 | if (rc) | |
305 | continue; | |
306 | rc = ntfs_collate_names(name, name_len, | |
307 | (ntfschar*)((u8*)a + | |
308 | le16_to_cpu(a->name_offset)), | |
309 | a->name_length, 1, CASE_SENSITIVE, | |
310 | upcase, upcase_len); | |
311 | if (rc == -1) | |
312 | return -ENOENT; | |
313 | if (rc) | |
314 | continue; | |
315 | } | |
316 | /* | |
317 | * The names match or @name not present and attribute is | |
318 | * unnamed. If no @val specified, we have found the attribute | |
319 | * and are done. | |
320 | */ | |
321 | if (!val) | |
322 | return 0; | |
323 | /* @val is present; compare values. */ | |
324 | else { | |
325 | register int rc; | |
326 | ||
327 | rc = memcmp(val, (u8*)a + le16_to_cpu( | |
328 | a->data.resident.value_offset), | |
329 | min_t(u32, val_len, le32_to_cpu( | |
330 | a->data.resident.value_length))); | |
331 | /* | |
332 | * If @val collates before the current attribute's | |
333 | * value, there is no matching attribute. | |
334 | */ | |
335 | if (!rc) { | |
336 | register u32 avl; | |
337 | ||
338 | avl = le32_to_cpu( | |
339 | a->data.resident.value_length); | |
340 | if (val_len == avl) | |
341 | return 0; | |
342 | if (val_len < avl) | |
343 | return -ENOENT; | |
344 | } else if (rc < 0) | |
345 | return -ENOENT; | |
346 | } | |
347 | } | |
348 | ntfs_error(vol->sb, "Inode is corrupt. Run chkdsk."); | |
349 | NVolSetErrors(vol); | |
350 | return -EIO; | |
351 | } | |
352 | ||
353 | /** | |
354 | * load_attribute_list - load an attribute list into memory | |
355 | * @vol: ntfs volume from which to read | |
356 | * @runlist: runlist of the attribute list | |
357 | * @al_start: destination buffer | |
358 | * @size: size of the destination buffer in bytes | |
359 | * @initialized_size: initialized size of the attribute list | |
360 | * | |
361 | * Walk the runlist @runlist and load all clusters from it copying them into | |
362 | * the linear buffer @al. The maximum number of bytes copied to @al is @size | |
363 | * bytes. Note, @size does not need to be a multiple of the cluster size. If | |
364 | * @initialized_size is less than @size, the region in @al between | |
365 | * @initialized_size and @size will be zeroed and not read from disk. | |
366 | * | |
367 | * Return 0 on success or -errno on error. | |
368 | */ | |
369 | int load_attribute_list(ntfs_volume *vol, runlist *runlist, u8 *al_start, | |
370 | const s64 size, const s64 initialized_size) | |
371 | { | |
372 | LCN lcn; | |
373 | u8 *al = al_start; | |
374 | u8 *al_end = al + initialized_size; | |
375 | runlist_element *rl; | |
376 | struct buffer_head *bh; | |
377 | struct super_block *sb; | |
378 | unsigned long block_size; | |
379 | unsigned long block, max_block; | |
380 | int err = 0; | |
381 | unsigned char block_size_bits; | |
382 | ||
383 | ntfs_debug("Entering."); | |
384 | if (!vol || !runlist || !al || size <= 0 || initialized_size < 0 || | |
385 | initialized_size > size) | |
386 | return -EINVAL; | |
387 | if (!initialized_size) { | |
388 | memset(al, 0, size); | |
389 | return 0; | |
390 | } | |
391 | sb = vol->sb; | |
392 | block_size = sb->s_blocksize; | |
393 | block_size_bits = sb->s_blocksize_bits; | |
394 | down_read(&runlist->lock); | |
395 | rl = runlist->rl; | |
396 | /* Read all clusters specified by the runlist one run at a time. */ | |
397 | while (rl->length) { | |
398 | lcn = ntfs_rl_vcn_to_lcn(rl, rl->vcn); | |
399 | ntfs_debug("Reading vcn = 0x%llx, lcn = 0x%llx.", | |
400 | (unsigned long long)rl->vcn, | |
401 | (unsigned long long)lcn); | |
402 | /* The attribute list cannot be sparse. */ | |
403 | if (lcn < 0) { | |
404 | ntfs_error(sb, "ntfs_rl_vcn_to_lcn() failed. Cannot " | |
405 | "read attribute list."); | |
406 | goto err_out; | |
407 | } | |
408 | block = lcn << vol->cluster_size_bits >> block_size_bits; | |
409 | /* Read the run from device in chunks of block_size bytes. */ | |
410 | max_block = block + (rl->length << vol->cluster_size_bits >> | |
411 | block_size_bits); | |
412 | ntfs_debug("max_block = 0x%lx.", max_block); | |
413 | do { | |
414 | ntfs_debug("Reading block = 0x%lx.", block); | |
415 | bh = sb_bread(sb, block); | |
416 | if (!bh) { | |
417 | ntfs_error(sb, "sb_bread() failed. Cannot " | |
418 | "read attribute list."); | |
419 | goto err_out; | |
420 | } | |
421 | if (al + block_size >= al_end) | |
422 | goto do_final; | |
423 | memcpy(al, bh->b_data, block_size); | |
424 | brelse(bh); | |
425 | al += block_size; | |
426 | } while (++block < max_block); | |
427 | rl++; | |
428 | } | |
429 | if (initialized_size < size) { | |
430 | initialize: | |
431 | memset(al_start + initialized_size, 0, size - initialized_size); | |
432 | } | |
433 | done: | |
434 | up_read(&runlist->lock); | |
435 | return err; | |
436 | do_final: | |
437 | if (al < al_end) { | |
438 | /* | |
439 | * Partial block. | |
440 | * | |
441 | * Note: The attribute list can be smaller than its allocation | |
442 | * by multiple clusters. This has been encountered by at least | |
443 | * two people running Windows XP, thus we cannot do any | |
444 | * truncation sanity checking here. (AIA) | |
445 | */ | |
446 | memcpy(al, bh->b_data, al_end - al); | |
447 | brelse(bh); | |
448 | if (initialized_size < size) | |
449 | goto initialize; | |
450 | goto done; | |
451 | } | |
452 | brelse(bh); | |
453 | /* Real overflow! */ | |
454 | ntfs_error(sb, "Attribute list buffer overflow. Read attribute list " | |
455 | "is truncated."); | |
456 | err_out: | |
457 | err = -EIO; | |
458 | goto done; | |
459 | } | |
460 | ||
461 | /** | |
462 | * ntfs_external_attr_find - find an attribute in the attribute list of an inode | |
463 | * @type: attribute type to find | |
464 | * @name: attribute name to find (optional, i.e. NULL means don't care) | |
465 | * @name_len: attribute name length (only needed if @name present) | |
466 | * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present) | |
467 | * @lowest_vcn: lowest vcn to find (optional, non-resident attributes only) | |
468 | * @val: attribute value to find (optional, resident attributes only) | |
469 | * @val_len: attribute value length | |
470 | * @ctx: search context with mft record and attribute to search from | |
471 | * | |
472 | * You should not need to call this function directly. Use ntfs_attr_lookup() | |
473 | * instead. | |
474 | * | |
475 | * Find an attribute by searching the attribute list for the corresponding | |
476 | * attribute list entry. Having found the entry, map the mft record if the | |
477 | * attribute is in a different mft record/inode, ntfs_attr_find() the attribute | |
478 | * in there and return it. | |
479 | * | |
480 | * On first search @ctx->ntfs_ino must be the base mft record and @ctx must | |
481 | * have been obtained from a call to ntfs_attr_get_search_ctx(). On subsequent | |
482 | * calls @ctx->ntfs_ino can be any extent inode, too (@ctx->base_ntfs_ino is | |
483 | * then the base inode). | |
484 | * | |
485 | * After finishing with the attribute/mft record you need to call | |
486 | * ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any | |
487 | * mapped inodes, etc). | |
488 | * | |
489 | * If the attribute is found, ntfs_external_attr_find() returns 0 and | |
490 | * @ctx->attr will point to the found attribute. @ctx->mrec will point to the | |
491 | * mft record in which @ctx->attr is located and @ctx->al_entry will point to | |
492 | * the attribute list entry for the attribute. | |
493 | * | |
494 | * If the attribute is not found, ntfs_external_attr_find() returns -ENOENT and | |
495 | * @ctx->attr will point to the attribute in the base mft record before which | |
496 | * the attribute being searched for would need to be inserted if such an action | |
497 | * were to be desired. @ctx->mrec will point to the mft record in which | |
498 | * @ctx->attr is located and @ctx->al_entry will point to the attribute list | |
499 | * entry of the attribute before which the attribute being searched for would | |
500 | * need to be inserted if such an action were to be desired. | |
501 | * | |
502 | * Thus to insert the not found attribute, one wants to add the attribute to | |
503 | * @ctx->mrec (the base mft record) and if there is not enough space, the | |
504 | * attribute should be placed in a newly allocated extent mft record. The | |
505 | * attribute list entry for the inserted attribute should be inserted in the | |
506 | * attribute list attribute at @ctx->al_entry. | |
507 | * | |
508 | * On actual error, ntfs_external_attr_find() returns -EIO. In this case | |
509 | * @ctx->attr is undefined and in particular do not rely on it not changing. | |
510 | */ | |
511 | static int ntfs_external_attr_find(const ATTR_TYPE type, | |
512 | const ntfschar *name, const u32 name_len, | |
513 | const IGNORE_CASE_BOOL ic, const VCN lowest_vcn, | |
514 | const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx) | |
515 | { | |
516 | ntfs_inode *base_ni, *ni; | |
517 | ntfs_volume *vol; | |
518 | ATTR_LIST_ENTRY *al_entry, *next_al_entry; | |
519 | u8 *al_start, *al_end; | |
520 | ATTR_RECORD *a; | |
521 | ntfschar *al_name; | |
522 | u32 al_name_len; | |
523 | int err = 0; | |
524 | static const char *es = " Unmount and run chkdsk."; | |
525 | ||
526 | ni = ctx->ntfs_ino; | |
527 | base_ni = ctx->base_ntfs_ino; | |
528 | ntfs_debug("Entering for inode 0x%lx, type 0x%x.", ni->mft_no, type); | |
529 | if (!base_ni) { | |
530 | /* First call happens with the base mft record. */ | |
531 | base_ni = ctx->base_ntfs_ino = ctx->ntfs_ino; | |
532 | ctx->base_mrec = ctx->mrec; | |
533 | } | |
534 | if (ni == base_ni) | |
535 | ctx->base_attr = ctx->attr; | |
536 | if (type == AT_END) | |
537 | goto not_found; | |
538 | vol = base_ni->vol; | |
539 | al_start = base_ni->attr_list; | |
540 | al_end = al_start + base_ni->attr_list_size; | |
541 | if (!ctx->al_entry) | |
542 | ctx->al_entry = (ATTR_LIST_ENTRY*)al_start; | |
543 | /* | |
544 | * Iterate over entries in attribute list starting at @ctx->al_entry, | |
545 | * or the entry following that, if @ctx->is_first is TRUE. | |
546 | */ | |
547 | if (ctx->is_first) { | |
548 | al_entry = ctx->al_entry; | |
549 | ctx->is_first = FALSE; | |
550 | } else | |
551 | al_entry = (ATTR_LIST_ENTRY*)((u8*)ctx->al_entry + | |
552 | le16_to_cpu(ctx->al_entry->length)); | |
553 | for (;; al_entry = next_al_entry) { | |
554 | /* Out of bounds check. */ | |
555 | if ((u8*)al_entry < base_ni->attr_list || | |
556 | (u8*)al_entry > al_end) | |
557 | break; /* Inode is corrupt. */ | |
558 | ctx->al_entry = al_entry; | |
559 | /* Catch the end of the attribute list. */ | |
560 | if ((u8*)al_entry == al_end) | |
561 | goto not_found; | |
562 | if (!al_entry->length) | |
563 | break; | |
564 | if ((u8*)al_entry + 6 > al_end || (u8*)al_entry + | |
565 | le16_to_cpu(al_entry->length) > al_end) | |
566 | break; | |
567 | next_al_entry = (ATTR_LIST_ENTRY*)((u8*)al_entry + | |
568 | le16_to_cpu(al_entry->length)); | |
569 | if (le32_to_cpu(al_entry->type) > le32_to_cpu(type)) | |
570 | goto not_found; | |
571 | if (type != al_entry->type) | |
572 | continue; | |
573 | /* | |
574 | * If @name is present, compare the two names. If @name is | |
575 | * missing, assume we want an unnamed attribute. | |
576 | */ | |
577 | al_name_len = al_entry->name_length; | |
578 | al_name = (ntfschar*)((u8*)al_entry + al_entry->name_offset); | |
579 | if (!name) { | |
580 | if (al_name_len) | |
581 | goto not_found; | |
582 | } else if (!ntfs_are_names_equal(al_name, al_name_len, name, | |
583 | name_len, ic, vol->upcase, vol->upcase_len)) { | |
584 | register int rc; | |
585 | ||
586 | rc = ntfs_collate_names(name, name_len, al_name, | |
587 | al_name_len, 1, IGNORE_CASE, | |
588 | vol->upcase, vol->upcase_len); | |
589 | /* | |
590 | * If @name collates before al_name, there is no | |
591 | * matching attribute. | |
592 | */ | |
593 | if (rc == -1) | |
594 | goto not_found; | |
595 | /* If the strings are not equal, continue search. */ | |
596 | if (rc) | |
597 | continue; | |
598 | /* | |
599 | * FIXME: Reverse engineering showed 0, IGNORE_CASE but | |
600 | * that is inconsistent with ntfs_attr_find(). The | |
601 | * subsequent rc checks were also different. Perhaps I | |
602 | * made a mistake in one of the two. Need to recheck | |
603 | * which is correct or at least see what is going on... | |
604 | * (AIA) | |
605 | */ | |
606 | rc = ntfs_collate_names(name, name_len, al_name, | |
607 | al_name_len, 1, CASE_SENSITIVE, | |
608 | vol->upcase, vol->upcase_len); | |
609 | if (rc == -1) | |
610 | goto not_found; | |
611 | if (rc) | |
612 | continue; | |
613 | } | |
614 | /* | |
615 | * The names match or @name not present and attribute is | |
616 | * unnamed. Now check @lowest_vcn. Continue search if the | |
617 | * next attribute list entry still fits @lowest_vcn. Otherwise | |
618 | * we have reached the right one or the search has failed. | |
619 | */ | |
620 | if (lowest_vcn && (u8*)next_al_entry >= al_start && | |
621 | (u8*)next_al_entry + 6 < al_end && | |
622 | (u8*)next_al_entry + le16_to_cpu( | |
623 | next_al_entry->length) <= al_end && | |
624 | sle64_to_cpu(next_al_entry->lowest_vcn) <= | |
625 | lowest_vcn && | |
626 | next_al_entry->type == al_entry->type && | |
627 | next_al_entry->name_length == al_name_len && | |
628 | ntfs_are_names_equal((ntfschar*)((u8*) | |
629 | next_al_entry + | |
630 | next_al_entry->name_offset), | |
631 | next_al_entry->name_length, | |
632 | al_name, al_name_len, CASE_SENSITIVE, | |
633 | vol->upcase, vol->upcase_len)) | |
634 | continue; | |
635 | if (MREF_LE(al_entry->mft_reference) == ni->mft_no) { | |
636 | if (MSEQNO_LE(al_entry->mft_reference) != ni->seq_no) { | |
637 | ntfs_error(vol->sb, "Found stale mft " | |
638 | "reference in attribute list " | |
639 | "of base inode 0x%lx.%s", | |
640 | base_ni->mft_no, es); | |
641 | err = -EIO; | |
642 | break; | |
643 | } | |
644 | } else { /* Mft references do not match. */ | |
645 | /* If there is a mapped record unmap it first. */ | |
646 | if (ni != base_ni) | |
647 | unmap_extent_mft_record(ni); | |
648 | /* Do we want the base record back? */ | |
649 | if (MREF_LE(al_entry->mft_reference) == | |
650 | base_ni->mft_no) { | |
651 | ni = ctx->ntfs_ino = base_ni; | |
652 | ctx->mrec = ctx->base_mrec; | |
653 | } else { | |
654 | /* We want an extent record. */ | |
655 | ctx->mrec = map_extent_mft_record(base_ni, | |
656 | le64_to_cpu( | |
657 | al_entry->mft_reference), &ni); | |
658 | if (IS_ERR(ctx->mrec)) { | |
659 | ntfs_error(vol->sb, "Failed to map " | |
660 | "extent mft record " | |
661 | "0x%lx of base inode " | |
662 | "0x%lx.%s", | |
663 | MREF_LE(al_entry-> | |
664 | mft_reference), | |
665 | base_ni->mft_no, es); | |
666 | err = PTR_ERR(ctx->mrec); | |
667 | if (err == -ENOENT) | |
668 | err = -EIO; | |
669 | /* Cause @ctx to be sanitized below. */ | |
670 | ni = NULL; | |
671 | break; | |
672 | } | |
673 | ctx->ntfs_ino = ni; | |
674 | } | |
675 | ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec + | |
676 | le16_to_cpu(ctx->mrec->attrs_offset)); | |
677 | } | |
678 | /* | |
679 | * ctx->vfs_ino, ctx->mrec, and ctx->attr now point to the | |
680 | * mft record containing the attribute represented by the | |
681 | * current al_entry. | |
682 | */ | |
683 | /* | |
684 | * We could call into ntfs_attr_find() to find the right | |
685 | * attribute in this mft record but this would be less | |
686 | * efficient and not quite accurate as ntfs_attr_find() ignores | |
687 | * the attribute instance numbers for example which become | |
688 | * important when one plays with attribute lists. Also, | |
689 | * because a proper match has been found in the attribute list | |
690 | * entry above, the comparison can now be optimized. So it is | |
691 | * worth re-implementing a simplified ntfs_attr_find() here. | |
692 | */ | |
693 | a = ctx->attr; | |
694 | /* | |
695 | * Use a manual loop so we can still use break and continue | |
696 | * with the same meanings as above. | |
697 | */ | |
698 | do_next_attr_loop: | |
699 | if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec + | |
700 | le32_to_cpu(ctx->mrec->bytes_allocated)) | |
701 | break; | |
702 | if (a->type == AT_END) | |
703 | continue; | |
704 | if (!a->length) | |
705 | break; | |
706 | if (al_entry->instance != a->instance) | |
707 | goto do_next_attr; | |
708 | /* | |
709 | * If the type and/or the name are mismatched between the | |
710 | * attribute list entry and the attribute record, there is | |
711 | * corruption so we break and return error EIO. | |
712 | */ | |
713 | if (al_entry->type != a->type) | |
714 | break; | |
715 | if (!ntfs_are_names_equal((ntfschar*)((u8*)a + | |
716 | le16_to_cpu(a->name_offset)), a->name_length, | |
717 | al_name, al_name_len, CASE_SENSITIVE, | |
718 | vol->upcase, vol->upcase_len)) | |
719 | break; | |
720 | ctx->attr = a; | |
721 | /* | |
722 | * If no @val specified or @val specified and it matches, we | |
723 | * have found it! | |
724 | */ | |
725 | if (!val || (!a->non_resident && le32_to_cpu( | |
726 | a->data.resident.value_length) == val_len && | |
727 | !memcmp((u8*)a + | |
728 | le16_to_cpu(a->data.resident.value_offset), | |
729 | val, val_len))) { | |
730 | ntfs_debug("Done, found."); | |
731 | return 0; | |
732 | } | |
733 | do_next_attr: | |
734 | /* Proceed to the next attribute in the current mft record. */ | |
735 | a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length)); | |
736 | goto do_next_attr_loop; | |
737 | } | |
738 | if (!err) { | |
739 | ntfs_error(vol->sb, "Base inode 0x%lx contains corrupt " | |
740 | "attribute list attribute.%s", base_ni->mft_no, | |
741 | es); | |
742 | err = -EIO; | |
743 | } | |
744 | if (ni != base_ni) { | |
745 | if (ni) | |
746 | unmap_extent_mft_record(ni); | |
747 | ctx->ntfs_ino = base_ni; | |
748 | ctx->mrec = ctx->base_mrec; | |
749 | ctx->attr = ctx->base_attr; | |
750 | } | |
751 | if (err != -ENOMEM) | |
752 | NVolSetErrors(vol); | |
753 | return err; | |
754 | not_found: | |
755 | /* | |
756 | * If we were looking for AT_END, we reset the search context @ctx and | |
757 | * use ntfs_attr_find() to seek to the end of the base mft record. | |
758 | */ | |
759 | if (type == AT_END) { | |
760 | ntfs_attr_reinit_search_ctx(ctx); | |
761 | return ntfs_attr_find(AT_END, name, name_len, ic, val, val_len, | |
762 | ctx); | |
763 | } | |
764 | /* | |
765 | * The attribute was not found. Before we return, we want to ensure | |
766 | * @ctx->mrec and @ctx->attr indicate the position at which the | |
767 | * attribute should be inserted in the base mft record. Since we also | |
768 | * want to preserve @ctx->al_entry we cannot reinitialize the search | |
769 | * context using ntfs_attr_reinit_search_ctx() as this would set | |
770 | * @ctx->al_entry to NULL. Thus we do the necessary bits manually (see | |
771 | * ntfs_attr_init_search_ctx() below). Note, we _only_ preserve | |
772 | * @ctx->al_entry as the remaining fields (base_*) are identical to | |
773 | * their non base_ counterparts and we cannot set @ctx->base_attr | |
774 | * correctly yet as we do not know what @ctx->attr will be set to by | |
775 | * the call to ntfs_attr_find() below. | |
776 | */ | |
777 | if (ni != base_ni) | |
778 | unmap_extent_mft_record(ni); | |
779 | ctx->mrec = ctx->base_mrec; | |
780 | ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec + | |
781 | le16_to_cpu(ctx->mrec->attrs_offset)); | |
782 | ctx->is_first = TRUE; | |
783 | ctx->ntfs_ino = base_ni; | |
784 | ctx->base_ntfs_ino = NULL; | |
785 | ctx->base_mrec = NULL; | |
786 | ctx->base_attr = NULL; | |
787 | /* | |
788 | * In case there are multiple matches in the base mft record, need to | |
789 | * keep enumerating until we get an attribute not found response (or | |
790 | * another error), otherwise we would keep returning the same attribute | |
791 | * over and over again and all programs using us for enumeration would | |
792 | * lock up in a tight loop. | |
793 | */ | |
794 | do { | |
795 | err = ntfs_attr_find(type, name, name_len, ic, val, val_len, | |
796 | ctx); | |
797 | } while (!err); | |
798 | ntfs_debug("Done, not found."); | |
799 | return err; | |
800 | } | |
801 | ||
802 | /** | |
803 | * ntfs_attr_lookup - find an attribute in an ntfs inode | |
804 | * @type: attribute type to find | |
805 | * @name: attribute name to find (optional, i.e. NULL means don't care) | |
806 | * @name_len: attribute name length (only needed if @name present) | |
807 | * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present) | |
808 | * @lowest_vcn: lowest vcn to find (optional, non-resident attributes only) | |
809 | * @val: attribute value to find (optional, resident attributes only) | |
810 | * @val_len: attribute value length | |
811 | * @ctx: search context with mft record and attribute to search from | |
812 | * | |
813 | * Find an attribute in an ntfs inode. On first search @ctx->ntfs_ino must | |
814 | * be the base mft record and @ctx must have been obtained from a call to | |
815 | * ntfs_attr_get_search_ctx(). | |
816 | * | |
817 | * This function transparently handles attribute lists and @ctx is used to | |
818 | * continue searches where they were left off at. | |
819 | * | |
820 | * After finishing with the attribute/mft record you need to call | |
821 | * ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any | |
822 | * mapped inodes, etc). | |
823 | * | |
824 | * Return 0 if the search was successful and -errno if not. | |
825 | * | |
826 | * When 0, @ctx->attr is the found attribute and it is in mft record | |
827 | * @ctx->mrec. If an attribute list attribute is present, @ctx->al_entry is | |
828 | * the attribute list entry of the found attribute. | |
829 | * | |
830 | * When -ENOENT, @ctx->attr is the attribute which collates just after the | |
831 | * attribute being searched for, i.e. if one wants to add the attribute to the | |
832 | * mft record this is the correct place to insert it into. If an attribute | |
833 | * list attribute is present, @ctx->al_entry is the attribute list entry which | |
834 | * collates just after the attribute list entry of the attribute being searched | |
835 | * for, i.e. if one wants to add the attribute to the mft record this is the | |
836 | * correct place to insert its attribute list entry into. | |
837 | * | |
838 | * When -errno != -ENOENT, an error occured during the lookup. @ctx->attr is | |
839 | * then undefined and in particular you should not rely on it not changing. | |
840 | */ | |
841 | int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name, | |
842 | const u32 name_len, const IGNORE_CASE_BOOL ic, | |
843 | const VCN lowest_vcn, const u8 *val, const u32 val_len, | |
844 | ntfs_attr_search_ctx *ctx) | |
845 | { | |
846 | ntfs_inode *base_ni; | |
847 | ||
848 | ntfs_debug("Entering."); | |
849 | if (ctx->base_ntfs_ino) | |
850 | base_ni = ctx->base_ntfs_ino; | |
851 | else | |
852 | base_ni = ctx->ntfs_ino; | |
853 | /* Sanity check, just for debugging really. */ | |
854 | BUG_ON(!base_ni); | |
855 | if (!NInoAttrList(base_ni) || type == AT_ATTRIBUTE_LIST) | |
856 | return ntfs_attr_find(type, name, name_len, ic, val, val_len, | |
857 | ctx); | |
858 | return ntfs_external_attr_find(type, name, name_len, ic, lowest_vcn, | |
859 | val, val_len, ctx); | |
860 | } | |
861 | ||
862 | /** | |
863 | * ntfs_attr_init_search_ctx - initialize an attribute search context | |
864 | * @ctx: attribute search context to initialize | |
865 | * @ni: ntfs inode with which to initialize the search context | |
866 | * @mrec: mft record with which to initialize the search context | |
867 | * | |
868 | * Initialize the attribute search context @ctx with @ni and @mrec. | |
869 | */ | |
870 | static inline void ntfs_attr_init_search_ctx(ntfs_attr_search_ctx *ctx, | |
871 | ntfs_inode *ni, MFT_RECORD *mrec) | |
872 | { | |
873 | ctx->mrec = mrec; | |
874 | /* Sanity checks are performed elsewhere. */ | |
875 | ctx->attr = (ATTR_RECORD*)((u8*)mrec + le16_to_cpu(mrec->attrs_offset)); | |
876 | ctx->is_first = TRUE; | |
877 | ctx->ntfs_ino = ni; | |
878 | ctx->al_entry = NULL; | |
879 | ctx->base_ntfs_ino = NULL; | |
880 | ctx->base_mrec = NULL; | |
881 | ctx->base_attr = NULL; | |
882 | } | |
883 | ||
884 | /** | |
885 | * ntfs_attr_reinit_search_ctx - reinitialize an attribute search context | |
886 | * @ctx: attribute search context to reinitialize | |
887 | * | |
888 | * Reinitialize the attribute search context @ctx, unmapping an associated | |
889 | * extent mft record if present, and initialize the search context again. | |
890 | * | |
891 | * This is used when a search for a new attribute is being started to reset | |
892 | * the search context to the beginning. | |
893 | */ | |
894 | void ntfs_attr_reinit_search_ctx(ntfs_attr_search_ctx *ctx) | |
895 | { | |
896 | if (likely(!ctx->base_ntfs_ino)) { | |
897 | /* No attribute list. */ | |
898 | ctx->is_first = TRUE; | |
899 | /* Sanity checks are performed elsewhere. */ | |
900 | ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec + | |
901 | le16_to_cpu(ctx->mrec->attrs_offset)); | |
902 | /* | |
903 | * This needs resetting due to ntfs_external_attr_find() which | |
904 | * can leave it set despite having zeroed ctx->base_ntfs_ino. | |
905 | */ | |
906 | ctx->al_entry = NULL; | |
907 | return; | |
908 | } /* Attribute list. */ | |
909 | if (ctx->ntfs_ino != ctx->base_ntfs_ino) | |
910 | unmap_extent_mft_record(ctx->ntfs_ino); | |
911 | ntfs_attr_init_search_ctx(ctx, ctx->base_ntfs_ino, ctx->base_mrec); | |
912 | return; | |
913 | } | |
914 | ||
915 | /** | |
916 | * ntfs_attr_get_search_ctx - allocate/initialize a new attribute search context | |
917 | * @ni: ntfs inode with which to initialize the search context | |
918 | * @mrec: mft record with which to initialize the search context | |
919 | * | |
920 | * Allocate a new attribute search context, initialize it with @ni and @mrec, | |
921 | * and return it. Return NULL if allocation failed. | |
922 | */ | |
923 | ntfs_attr_search_ctx *ntfs_attr_get_search_ctx(ntfs_inode *ni, MFT_RECORD *mrec) | |
924 | { | |
925 | ntfs_attr_search_ctx *ctx; | |
926 | ||
927 | ctx = kmem_cache_alloc(ntfs_attr_ctx_cache, SLAB_NOFS); | |
928 | if (ctx) | |
929 | ntfs_attr_init_search_ctx(ctx, ni, mrec); | |
930 | return ctx; | |
931 | } | |
932 | ||
933 | /** | |
934 | * ntfs_attr_put_search_ctx - release an attribute search context | |
935 | * @ctx: attribute search context to free | |
936 | * | |
937 | * Release the attribute search context @ctx, unmapping an associated extent | |
938 | * mft record if present. | |
939 | */ | |
940 | void ntfs_attr_put_search_ctx(ntfs_attr_search_ctx *ctx) | |
941 | { | |
942 | if (ctx->base_ntfs_ino && ctx->ntfs_ino != ctx->base_ntfs_ino) | |
943 | unmap_extent_mft_record(ctx->ntfs_ino); | |
944 | kmem_cache_free(ntfs_attr_ctx_cache, ctx); | |
945 | return; | |
946 | } | |
947 | ||
948 | /** | |
949 | * ntfs_attr_find_in_attrdef - find an attribute in the $AttrDef system file | |
950 | * @vol: ntfs volume to which the attribute belongs | |
951 | * @type: attribute type which to find | |
952 | * | |
953 | * Search for the attribute definition record corresponding to the attribute | |
954 | * @type in the $AttrDef system file. | |
955 | * | |
956 | * Return the attribute type definition record if found and NULL if not found. | |
957 | */ | |
958 | static ATTR_DEF *ntfs_attr_find_in_attrdef(const ntfs_volume *vol, | |
959 | const ATTR_TYPE type) | |
960 | { | |
961 | ATTR_DEF *ad; | |
962 | ||
963 | BUG_ON(!vol->attrdef); | |
964 | BUG_ON(!type); | |
965 | for (ad = vol->attrdef; (u8*)ad - (u8*)vol->attrdef < | |
966 | vol->attrdef_size && ad->type; ++ad) { | |
967 | /* We have not found it yet, carry on searching. */ | |
968 | if (likely(le32_to_cpu(ad->type) < le32_to_cpu(type))) | |
969 | continue; | |
970 | /* We found the attribute; return it. */ | |
971 | if (likely(ad->type == type)) | |
972 | return ad; | |
973 | /* We have gone too far already. No point in continuing. */ | |
974 | break; | |
975 | } | |
976 | /* Attribute not found. */ | |
977 | ntfs_debug("Attribute type 0x%x not found in $AttrDef.", | |
978 | le32_to_cpu(type)); | |
979 | return NULL; | |
980 | } | |
981 | ||
982 | /** | |
983 | * ntfs_attr_size_bounds_check - check a size of an attribute type for validity | |
984 | * @vol: ntfs volume to which the attribute belongs | |
985 | * @type: attribute type which to check | |
986 | * @size: size which to check | |
987 | * | |
988 | * Check whether the @size in bytes is valid for an attribute of @type on the | |
989 | * ntfs volume @vol. This information is obtained from $AttrDef system file. | |
990 | * | |
991 | * Return 0 if valid, -ERANGE if not valid, or -ENOENT if the attribute is not | |
992 | * listed in $AttrDef. | |
993 | */ | |
994 | int ntfs_attr_size_bounds_check(const ntfs_volume *vol, const ATTR_TYPE type, | |
995 | const s64 size) | |
996 | { | |
997 | ATTR_DEF *ad; | |
998 | ||
999 | BUG_ON(size < 0); | |
1000 | /* | |
1001 | * $ATTRIBUTE_LIST has a maximum size of 256kiB, but this is not | |
1002 | * listed in $AttrDef. | |
1003 | */ | |
1004 | if (unlikely(type == AT_ATTRIBUTE_LIST && size > 256 * 1024)) | |
1005 | return -ERANGE; | |
1006 | /* Get the $AttrDef entry for the attribute @type. */ | |
1007 | ad = ntfs_attr_find_in_attrdef(vol, type); | |
1008 | if (unlikely(!ad)) | |
1009 | return -ENOENT; | |
1010 | /* Do the bounds check. */ | |
1011 | if (((sle64_to_cpu(ad->min_size) > 0) && | |
1012 | size < sle64_to_cpu(ad->min_size)) || | |
1013 | ((sle64_to_cpu(ad->max_size) > 0) && size > | |
1014 | sle64_to_cpu(ad->max_size))) | |
1015 | return -ERANGE; | |
1016 | return 0; | |
1017 | } | |
1018 | ||
1019 | /** | |
1020 | * ntfs_attr_can_be_non_resident - check if an attribute can be non-resident | |
1021 | * @vol: ntfs volume to which the attribute belongs | |
1022 | * @type: attribute type which to check | |
1023 | * | |
1024 | * Check whether the attribute of @type on the ntfs volume @vol is allowed to | |
1025 | * be non-resident. This information is obtained from $AttrDef system file. | |
1026 | * | |
1027 | * Return 0 if the attribute is allowed to be non-resident, -EPERM if not, or | |
1028 | * -ENOENT if the attribute is not listed in $AttrDef. | |
1029 | */ | |
1030 | int ntfs_attr_can_be_non_resident(const ntfs_volume *vol, const ATTR_TYPE type) | |
1031 | { | |
1032 | ATTR_DEF *ad; | |
1033 | ||
1034 | /* | |
1035 | * $DATA is always allowed to be non-resident even if $AttrDef does not | |
1036 | * specify this in the flags of the $DATA attribute definition record. | |
1037 | */ | |
1038 | if (type == AT_DATA) | |
1039 | return 0; | |
1040 | /* Find the attribute definition record in $AttrDef. */ | |
1041 | ad = ntfs_attr_find_in_attrdef(vol, type); | |
1042 | if (unlikely(!ad)) | |
1043 | return -ENOENT; | |
1044 | /* Check the flags and return the result. */ | |
1045 | if (ad->flags & CAN_BE_NON_RESIDENT) | |
1046 | return 0; | |
1047 | return -EPERM; | |
1048 | } | |
1049 | ||
1050 | /** | |
1051 | * ntfs_attr_can_be_resident - check if an attribute can be resident | |
1052 | * @vol: ntfs volume to which the attribute belongs | |
1053 | * @type: attribute type which to check | |
1054 | * | |
1055 | * Check whether the attribute of @type on the ntfs volume @vol is allowed to | |
1056 | * be resident. This information is derived from our ntfs knowledge and may | |
1057 | * not be completely accurate, especially when user defined attributes are | |
1058 | * present. Basically we allow everything to be resident except for index | |
1059 | * allocation and $EA attributes. | |
1060 | * | |
1061 | * Return 0 if the attribute is allowed to be non-resident and -EPERM if not. | |
1062 | * | |
1063 | * Warning: In the system file $MFT the attribute $Bitmap must be non-resident | |
1064 | * otherwise windows will not boot (blue screen of death)! We cannot | |
1065 | * check for this here as we do not know which inode's $Bitmap is | |
1066 | * being asked about so the caller needs to special case this. | |
1067 | */ | |
1068 | int ntfs_attr_can_be_resident(const ntfs_volume *vol, const ATTR_TYPE type) | |
1069 | { | |
1070 | if (type != AT_INDEX_ALLOCATION && type != AT_EA) | |
1071 | return 0; | |
1072 | return -EPERM; | |
1073 | } | |
1074 | ||
1075 | /** | |
1076 | * ntfs_attr_record_resize - resize an attribute record | |
1077 | * @m: mft record containing attribute record | |
1078 | * @a: attribute record to resize | |
1079 | * @new_size: new size in bytes to which to resize the attribute record @a | |
1080 | * | |
1081 | * Resize the attribute record @a, i.e. the resident part of the attribute, in | |
1082 | * the mft record @m to @new_size bytes. | |
1083 | * | |
1084 | * Return 0 on success and -errno on error. The following error codes are | |
1085 | * defined: | |
1086 | * -ENOSPC - Not enough space in the mft record @m to perform the resize. | |
1087 | * | |
1088 | * Note: On error, no modifications have been performed whatsoever. | |
1089 | * | |
1090 | * Warning: If you make a record smaller without having copied all the data you | |
1091 | * are interested in the data may be overwritten. | |
1092 | */ | |
1093 | int ntfs_attr_record_resize(MFT_RECORD *m, ATTR_RECORD *a, u32 new_size) | |
1094 | { | |
1095 | ntfs_debug("Entering for new_size %u.", new_size); | |
1096 | /* Align to 8 bytes if it is not already done. */ | |
1097 | if (new_size & 7) | |
1098 | new_size = (new_size + 7) & ~7; | |
1099 | /* If the actual attribute length has changed, move things around. */ | |
1100 | if (new_size != le32_to_cpu(a->length)) { | |
1101 | u32 new_muse = le32_to_cpu(m->bytes_in_use) - | |
1102 | le32_to_cpu(a->length) + new_size; | |
1103 | /* Not enough space in this mft record. */ | |
1104 | if (new_muse > le32_to_cpu(m->bytes_allocated)) | |
1105 | return -ENOSPC; | |
1106 | /* Move attributes following @a to their new location. */ | |
1107 | memmove((u8*)a + new_size, (u8*)a + le32_to_cpu(a->length), | |
1108 | le32_to_cpu(m->bytes_in_use) - ((u8*)a - | |
1109 | (u8*)m) - le32_to_cpu(a->length)); | |
1110 | /* Adjust @m to reflect the change in used space. */ | |
1111 | m->bytes_in_use = cpu_to_le32(new_muse); | |
1112 | /* Adjust @a to reflect the new size. */ | |
1113 | if (new_size >= offsetof(ATTR_REC, length) + sizeof(a->length)) | |
1114 | a->length = cpu_to_le32(new_size); | |
1115 | } | |
1116 | return 0; | |
1117 | } | |
1118 | ||
1119 | /** | |
1120 | * ntfs_attr_set - fill (a part of) an attribute with a byte | |
1121 | * @ni: ntfs inode describing the attribute to fill | |
1122 | * @ofs: offset inside the attribute at which to start to fill | |
1123 | * @cnt: number of bytes to fill | |
1124 | * @val: the unsigned 8-bit value with which to fill the attribute | |
1125 | * | |
1126 | * Fill @cnt bytes of the attribute described by the ntfs inode @ni starting at | |
1127 | * byte offset @ofs inside the attribute with the constant byte @val. | |
1128 | * | |
1129 | * This function is effectively like memset() applied to an ntfs attribute. | |
1130 | * | |
1131 | * Return 0 on success and -errno on error. An error code of -ESPIPE means | |
1132 | * that @ofs + @cnt were outside the end of the attribute and no write was | |
1133 | * performed. | |
1134 | */ | |
1135 | int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val) | |
1136 | { | |
1137 | ntfs_volume *vol = ni->vol; | |
1138 | struct address_space *mapping; | |
1139 | struct page *page; | |
1140 | u8 *kaddr; | |
1141 | pgoff_t idx, end; | |
1142 | unsigned int start_ofs, end_ofs, size; | |
1143 | ||
1144 | ntfs_debug("Entering for ofs 0x%llx, cnt 0x%llx, val 0x%hx.", | |
1145 | (long long)ofs, (long long)cnt, val); | |
1146 | BUG_ON(ofs < 0); | |
1147 | BUG_ON(cnt < 0); | |
1148 | if (!cnt) | |
1149 | goto done; | |
1150 | mapping = VFS_I(ni)->i_mapping; | |
1151 | /* Work out the starting index and page offset. */ | |
1152 | idx = ofs >> PAGE_CACHE_SHIFT; | |
1153 | start_ofs = ofs & ~PAGE_CACHE_MASK; | |
1154 | /* Work out the ending index and page offset. */ | |
1155 | end = ofs + cnt; | |
1156 | end_ofs = end & ~PAGE_CACHE_MASK; | |
1157 | /* If the end is outside the inode size return -ESPIPE. */ | |
1158 | if (unlikely(end > VFS_I(ni)->i_size)) { | |
1159 | ntfs_error(vol->sb, "Request exceeds end of attribute."); | |
1160 | return -ESPIPE; | |
1161 | } | |
1162 | end >>= PAGE_CACHE_SHIFT; | |
1163 | /* If there is a first partial page, need to do it the slow way. */ | |
1164 | if (start_ofs) { | |
1165 | page = read_cache_page(mapping, idx, | |
1166 | (filler_t*)mapping->a_ops->readpage, NULL); | |
1167 | if (IS_ERR(page)) { | |
1168 | ntfs_error(vol->sb, "Failed to read first partial " | |
1169 | "page (sync error, index 0x%lx).", idx); | |
1170 | return PTR_ERR(page); | |
1171 | } | |
1172 | wait_on_page_locked(page); | |
1173 | if (unlikely(!PageUptodate(page))) { | |
1174 | ntfs_error(vol->sb, "Failed to read first partial page " | |
1175 | "(async error, index 0x%lx).", idx); | |
1176 | page_cache_release(page); | |
1177 | return PTR_ERR(page); | |
1178 | } | |
1179 | /* | |
1180 | * If the last page is the same as the first page, need to | |
1181 | * limit the write to the end offset. | |
1182 | */ | |
1183 | size = PAGE_CACHE_SIZE; | |
1184 | if (idx == end) | |
1185 | size = end_ofs; | |
1186 | kaddr = kmap_atomic(page, KM_USER0); | |
1187 | memset(kaddr + start_ofs, val, size - start_ofs); | |
1188 | flush_dcache_page(page); | |
1189 | kunmap_atomic(kaddr, KM_USER0); | |
1190 | set_page_dirty(page); | |
1191 | page_cache_release(page); | |
1192 | if (idx == end) | |
1193 | goto done; | |
1194 | idx++; | |
1195 | } | |
1196 | /* Do the whole pages the fast way. */ | |
1197 | for (; idx < end; idx++) { | |
1198 | /* Find or create the current page. (The page is locked.) */ | |
1199 | page = grab_cache_page(mapping, idx); | |
1200 | if (unlikely(!page)) { | |
1201 | ntfs_error(vol->sb, "Insufficient memory to grab " | |
1202 | "page (index 0x%lx).", idx); | |
1203 | return -ENOMEM; | |
1204 | } | |
1205 | kaddr = kmap_atomic(page, KM_USER0); | |
1206 | memset(kaddr, val, PAGE_CACHE_SIZE); | |
1207 | flush_dcache_page(page); | |
1208 | kunmap_atomic(kaddr, KM_USER0); | |
1209 | /* | |
1210 | * If the page has buffers, mark them uptodate since buffer | |
1211 | * state and not page state is definitive in 2.6 kernels. | |
1212 | */ | |
1213 | if (page_has_buffers(page)) { | |
1214 | struct buffer_head *bh, *head; | |
1215 | ||
1216 | bh = head = page_buffers(page); | |
1217 | do { | |
1218 | set_buffer_uptodate(bh); | |
1219 | } while ((bh = bh->b_this_page) != head); | |
1220 | } | |
1221 | /* Now that buffers are uptodate, set the page uptodate, too. */ | |
1222 | SetPageUptodate(page); | |
1223 | /* | |
1224 | * Set the page and all its buffers dirty and mark the inode | |
1225 | * dirty, too. The VM will write the page later on. | |
1226 | */ | |
1227 | set_page_dirty(page); | |
1228 | /* Finally unlock and release the page. */ | |
1229 | unlock_page(page); | |
1230 | page_cache_release(page); | |
1231 | } | |
1232 | /* If there is a last partial page, need to do it the slow way. */ | |
1233 | if (end_ofs) { | |
1234 | page = read_cache_page(mapping, idx, | |
1235 | (filler_t*)mapping->a_ops->readpage, NULL); | |
1236 | if (IS_ERR(page)) { | |
1237 | ntfs_error(vol->sb, "Failed to read last partial page " | |
1238 | "(sync error, index 0x%lx).", idx); | |
1239 | return PTR_ERR(page); | |
1240 | } | |
1241 | wait_on_page_locked(page); | |
1242 | if (unlikely(!PageUptodate(page))) { | |
1243 | ntfs_error(vol->sb, "Failed to read last partial page " | |
1244 | "(async error, index 0x%lx).", idx); | |
1245 | page_cache_release(page); | |
1246 | return PTR_ERR(page); | |
1247 | } | |
1248 | kaddr = kmap_atomic(page, KM_USER0); | |
1249 | memset(kaddr, val, end_ofs); | |
1250 | flush_dcache_page(page); | |
1251 | kunmap_atomic(kaddr, KM_USER0); | |
1252 | set_page_dirty(page); | |
1253 | page_cache_release(page); | |
1254 | } | |
1255 | done: | |
1256 | ntfs_debug("Done."); | |
1257 | return 0; | |
1258 | } |