1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * This file is part of UBIFS.
4 *
5 * Copyright (C) 2006-2008 Nokia Corporation
6 *
7 * Authors: Adrian Hunter
8 * Artem Bityutskiy (Битюцкий Артём)
9 */
10
11 /*
12 * This file implements the scan which is a general-purpose function for
13 * determining what nodes are in an eraseblock. The scan is used to replay the
14 * journal, to do garbage collection. for the TNC in-the-gaps method, and by
15 * debugging functions.
16 */
17
18 #ifdef __UBOOT__
19 #include <hexdump.h>
20 #include <linux/err.h>
21 #endif
22 #include "ubifs.h"
23
24 /**
25 * scan_padding_bytes - scan for padding bytes.
26 * @buf: buffer to scan
27 * @len: length of buffer
28 *
29 * This function returns the number of padding bytes on success and
30 * %SCANNED_GARBAGE on failure.
31 */
scan_padding_bytes(void * buf,int len)32 static int scan_padding_bytes(void *buf, int len)
33 {
34 int pad_len = 0, max_pad_len = min_t(int, UBIFS_PAD_NODE_SZ, len);
35 uint8_t *p = buf;
36
37 dbg_scan("not a node");
38
39 while (pad_len < max_pad_len && *p++ == UBIFS_PADDING_BYTE)
40 pad_len += 1;
41
42 if (!pad_len || (pad_len & 7))
43 return SCANNED_GARBAGE;
44
45 dbg_scan("%d padding bytes", pad_len);
46
47 return pad_len;
48 }
49
50 /**
51 * ubifs_scan_a_node - scan for a node or padding.
52 * @c: UBIFS file-system description object
53 * @buf: buffer to scan
54 * @len: length of buffer
55 * @lnum: logical eraseblock number
56 * @offs: offset within the logical eraseblock
57 * @quiet: print no messages
58 *
59 * This function returns a scanning code to indicate what was scanned.
60 */
ubifs_scan_a_node(const struct ubifs_info * c,void * buf,int len,int lnum,int offs,int quiet)61 int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum,
62 int offs, int quiet)
63 {
64 struct ubifs_ch *ch = buf;
65 uint32_t magic;
66
67 magic = le32_to_cpu(ch->magic);
68
69 if (magic == 0xFFFFFFFF) {
70 dbg_scan("hit empty space at LEB %d:%d", lnum, offs);
71 return SCANNED_EMPTY_SPACE;
72 }
73
74 if (magic != UBIFS_NODE_MAGIC)
75 return scan_padding_bytes(buf, len);
76
77 if (len < UBIFS_CH_SZ)
78 return SCANNED_GARBAGE;
79
80 dbg_scan("scanning %s at LEB %d:%d",
81 dbg_ntype(ch->node_type), lnum, offs);
82
83 if (ubifs_check_node(c, buf, lnum, offs, quiet, 1))
84 return SCANNED_A_CORRUPT_NODE;
85
86 if (ch->node_type == UBIFS_PAD_NODE) {
87 struct ubifs_pad_node *pad = buf;
88 int pad_len = le32_to_cpu(pad->pad_len);
89 int node_len = le32_to_cpu(ch->len);
90
91 /* Validate the padding node */
92 if (pad_len < 0 ||
93 offs + node_len + pad_len > c->leb_size) {
94 if (!quiet) {
95 ubifs_err(c, "bad pad node at LEB %d:%d",
96 lnum, offs);
97 ubifs_dump_node(c, pad);
98 }
99 return SCANNED_A_BAD_PAD_NODE;
100 }
101
102 /* Make the node pads to 8-byte boundary */
103 if ((node_len + pad_len) & 7) {
104 if (!quiet)
105 ubifs_err(c, "bad padding length %d - %d",
106 offs, offs + node_len + pad_len);
107 return SCANNED_A_BAD_PAD_NODE;
108 }
109
110 dbg_scan("%d bytes padded at LEB %d:%d, offset now %d", pad_len,
111 lnum, offs, ALIGN(offs + node_len + pad_len, 8));
112
113 return node_len + pad_len;
114 }
115
116 return SCANNED_A_NODE;
117 }
118
119 /**
120 * ubifs_start_scan - create LEB scanning information at start of scan.
121 * @c: UBIFS file-system description object
122 * @lnum: logical eraseblock number
123 * @offs: offset to start at (usually zero)
124 * @sbuf: scan buffer (must be c->leb_size)
125 *
126 * This function returns the scanned information on success and a negative error
127 * code on failure.
128 */
ubifs_start_scan(const struct ubifs_info * c,int lnum,int offs,void * sbuf)129 struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,
130 int offs, void *sbuf)
131 {
132 struct ubifs_scan_leb *sleb;
133 int err;
134
135 dbg_scan("scan LEB %d:%d", lnum, offs);
136
137 sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS);
138 if (!sleb)
139 return ERR_PTR(-ENOMEM);
140
141 sleb->lnum = lnum;
142 INIT_LIST_HEAD(&sleb->nodes);
143 sleb->buf = sbuf;
144
145 err = ubifs_leb_read(c, lnum, sbuf + offs, offs, c->leb_size - offs, 0);
146 if (err && err != -EBADMSG) {
147 ubifs_err(c, "cannot read %d bytes from LEB %d:%d, error %d",
148 c->leb_size - offs, lnum, offs, err);
149 kfree(sleb);
150 return ERR_PTR(err);
151 }
152
153 /*
154 * Note, we ignore integrity errors (EBASMSG) because all the nodes are
155 * protected by CRC checksums.
156 */
157 return sleb;
158 }
159
160 /**
161 * ubifs_end_scan - update LEB scanning information at end of scan.
162 * @c: UBIFS file-system description object
163 * @sleb: scanning information
164 * @lnum: logical eraseblock number
165 * @offs: offset to start at (usually zero)
166 */
ubifs_end_scan(const struct ubifs_info * c,struct ubifs_scan_leb * sleb,int lnum,int offs)167 void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
168 int lnum, int offs)
169 {
170 lnum = lnum;
171 dbg_scan("stop scanning LEB %d at offset %d", lnum, offs);
172 ubifs_assert(offs % c->min_io_size == 0);
173
174 sleb->endpt = ALIGN(offs, c->min_io_size);
175 }
176
177 /**
178 * ubifs_add_snod - add a scanned node to LEB scanning information.
179 * @c: UBIFS file-system description object
180 * @sleb: scanning information
181 * @buf: buffer containing node
182 * @offs: offset of node on flash
183 *
184 * This function returns %0 on success and a negative error code on failure.
185 */
ubifs_add_snod(const struct ubifs_info * c,struct ubifs_scan_leb * sleb,void * buf,int offs)186 int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
187 void *buf, int offs)
188 {
189 struct ubifs_ch *ch = buf;
190 struct ubifs_ino_node *ino = buf;
191 struct ubifs_scan_node *snod;
192
193 snod = kmalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);
194 if (!snod)
195 return -ENOMEM;
196
197 snod->sqnum = le64_to_cpu(ch->sqnum);
198 snod->type = ch->node_type;
199 snod->offs = offs;
200 snod->len = le32_to_cpu(ch->len);
201 snod->node = buf;
202
203 switch (ch->node_type) {
204 case UBIFS_INO_NODE:
205 case UBIFS_DENT_NODE:
206 case UBIFS_XENT_NODE:
207 case UBIFS_DATA_NODE:
208 /*
209 * The key is in the same place in all keyed
210 * nodes.
211 */
212 key_read(c, &ino->key, &snod->key);
213 break;
214 default:
215 invalid_key_init(c, &snod->key);
216 break;
217 }
218 list_add_tail(&snod->list, &sleb->nodes);
219 sleb->nodes_cnt += 1;
220 return 0;
221 }
222
223 /**
224 * ubifs_scanned_corruption - print information after UBIFS scanned corruption.
225 * @c: UBIFS file-system description object
226 * @lnum: LEB number of corruption
227 * @offs: offset of corruption
228 * @buf: buffer containing corruption
229 */
ubifs_scanned_corruption(const struct ubifs_info * c,int lnum,int offs,void * buf)230 void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
231 void *buf)
232 {
233 int len;
234
235 ubifs_err(c, "corruption at LEB %d:%d", lnum, offs);
236 len = c->leb_size - offs;
237 if (len > 8192)
238 len = 8192;
239 ubifs_err(c, "first %d bytes from LEB %d:%d", len, lnum, offs);
240 print_hex_dump("", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);
241 }
242
243 /**
244 * ubifs_scan - scan a logical eraseblock.
245 * @c: UBIFS file-system description object
246 * @lnum: logical eraseblock number
247 * @offs: offset to start at (usually zero)
248 * @sbuf: scan buffer (must be of @c->leb_size bytes in size)
249 * @quiet: print no messages
250 *
251 * This function scans LEB number @lnum and returns complete information about
252 * its contents. Returns the scanned information in case of success and,
253 * %-EUCLEAN if the LEB neads recovery, and other negative error codes in case
254 * of failure.
255 *
256 * If @quiet is non-zero, this function does not print large and scary
257 * error messages and flash dumps in case of errors.
258 */
ubifs_scan(const struct ubifs_info * c,int lnum,int offs,void * sbuf,int quiet)259 struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
260 int offs, void *sbuf, int quiet)
261 {
262 void *buf = sbuf + offs;
263 int err, len = c->leb_size - offs;
264 struct ubifs_scan_leb *sleb;
265
266 sleb = ubifs_start_scan(c, lnum, offs, sbuf);
267 if (IS_ERR(sleb))
268 return sleb;
269
270 while (len >= 8) {
271 struct ubifs_ch *ch = buf;
272 int node_len, ret;
273
274 dbg_scan("look at LEB %d:%d (%d bytes left)",
275 lnum, offs, len);
276
277 cond_resched();
278
279 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
280 if (ret > 0) {
281 /* Padding bytes or a valid padding node */
282 offs += ret;
283 buf += ret;
284 len -= ret;
285 continue;
286 }
287
288 if (ret == SCANNED_EMPTY_SPACE)
289 /* Empty space is checked later */
290 break;
291
292 switch (ret) {
293 case SCANNED_GARBAGE:
294 ubifs_err(c, "garbage");
295 goto corrupted;
296 case SCANNED_A_NODE:
297 break;
298 case SCANNED_A_CORRUPT_NODE:
299 case SCANNED_A_BAD_PAD_NODE:
300 ubifs_err(c, "bad node");
301 goto corrupted;
302 default:
303 ubifs_err(c, "unknown");
304 err = -EINVAL;
305 goto error;
306 }
307
308 err = ubifs_add_snod(c, sleb, buf, offs);
309 if (err)
310 goto error;
311
312 node_len = ALIGN(le32_to_cpu(ch->len), 8);
313 offs += node_len;
314 buf += node_len;
315 len -= node_len;
316 }
317
318 if (offs % c->min_io_size) {
319 if (!quiet)
320 ubifs_err(c, "empty space starts at non-aligned offset %d",
321 offs);
322 goto corrupted;
323 }
324
325 ubifs_end_scan(c, sleb, lnum, offs);
326
327 for (; len > 4; offs += 4, buf = buf + 4, len -= 4)
328 if (*(uint32_t *)buf != 0xffffffff)
329 break;
330 for (; len; offs++, buf++, len--)
331 if (*(uint8_t *)buf != 0xff) {
332 if (!quiet)
333 ubifs_err(c, "corrupt empty space at LEB %d:%d",
334 lnum, offs);
335 goto corrupted;
336 }
337
338 return sleb;
339
340 corrupted:
341 if (!quiet) {
342 ubifs_scanned_corruption(c, lnum, offs, buf);
343 ubifs_err(c, "LEB %d scanning failed", lnum);
344 }
345 err = -EUCLEAN;
346 ubifs_scan_destroy(sleb);
347 return ERR_PTR(err);
348
349 error:
350 ubifs_err(c, "LEB %d scanning failed, error %d", lnum, err);
351 ubifs_scan_destroy(sleb);
352 return ERR_PTR(err);
353 }
354
355 /**
356 * ubifs_scan_destroy - destroy LEB scanning information.
357 * @sleb: scanning information to free
358 */
ubifs_scan_destroy(struct ubifs_scan_leb * sleb)359 void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)
360 {
361 struct ubifs_scan_node *node;
362 struct list_head *head;
363
364 head = &sleb->nodes;
365 while (!list_empty(head)) {
366 node = list_entry(head->next, struct ubifs_scan_node, list);
367 list_del(&node->list);
368 kfree(node);
369 }
370 kfree(sleb);
371 }
372