1 /*
2 * Copyright (c) 2014 SGI.
3 * Copyright (c) 2018 Collabora Ltd.
4 * All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it would be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 */
16
17 /*
18 * This code is adapted from the Linux Kernel. We have a
19 * userspace version here such that the hashes will match that
20 * implementation.
21 */
22
23 #include "config.h"
24 #include <stdint.h>
25 #include <unistd.h>
26 #include <string.h>
27 #include <limits.h>
28 #include <errno.h>
29
30 #include "ext2_fs.h"
31 #include "ext2fs.h"
32 #include "ext2fsP.h"
33
34 /* Encoding a unicode version number as a single unsigned int. */
35 #define UNICODE_MAJ_SHIFT (16)
36 #define UNICODE_MIN_SHIFT (8)
37
38 #define UNICODE_AGE(MAJ, MIN, REV) \
39 (((unsigned int)(MAJ) << UNICODE_MAJ_SHIFT) | \
40 ((unsigned int)(MIN) << UNICODE_MIN_SHIFT) | \
41 ((unsigned int)(REV)))
42
43 /* Needed in struct utf8cursor below. */
44 #define UTF8HANGULLEAF (12)
45
46 /*
47 * Cursor structure used by the normalizer.
48 */
49 struct utf8cursor {
50 const struct utf8data *data;
51 const char *s;
52 const char *p;
53 const char *ss;
54 const char *sp;
55 unsigned int len;
56 unsigned int slen;
57 short int ccc;
58 short int nccc;
59 unsigned char hangul[UTF8HANGULLEAF];
60 };
61
62 /*
63 * Initialize a utf8cursor to normalize a string.
64 * Returns 0 on success.
65 * Returns -1 on failure.
66 */
67 // extern int utf8cursor(struct utf8cursor *u8c, const struct utf8data *data,
68 // const char *s);
69 // extern int utf8ncursor(struct utf8cursor *u8c, const struct utf8data *data,
70 // const char *s, size_t len);
71
72 /*
73 * Get the next byte in the normalization.
74 * Returns a value > 0 && < 256 on success.
75 * Returns 0 when the end of the normalization is reached.
76 * Returns -1 if the string being normalized is not valid UTF-8.
77 */
78 // extern int utf8byte(struct utf8cursor *u8c);
79
80
81 struct utf8data {
82 unsigned int maxage;
83 unsigned int offset;
84 };
85
86 #define __INCLUDED_FROM_UTF8NORM_C__
87 #include "utf8data.h"
88 #undef __INCLUDED_FROM_UTF8NORM_C__
89
90 #define ARRAY_SIZE(array) \
91 (sizeof(array) / sizeof(array[0]))
92
93 #if 0
94 /* Highest unicode version supported by the data tables. */
95 static int utf8version_is_supported(uint8_t maj, uint8_t min, uint8_t rev)
96 {
97 int i = ARRAY_SIZE(utf8agetab) - 1;
98 unsigned int sb_utf8version = UNICODE_AGE(maj, min, rev);
99
100 while (i >= 0 && utf8agetab[i] != 0) {
101 if (sb_utf8version == utf8agetab[i])
102 return 1;
103 i--;
104 }
105 return 0;
106 }
107 #endif
108
109 #if 0
110 static int utf8version_latest(void)
111 {
112 return utf8vers;
113 }
114 #endif
115
116 /*
117 * UTF-8 valid ranges.
118 *
119 * The UTF-8 encoding spreads the bits of a 32bit word over several
120 * bytes. This table gives the ranges that can be held and how they'd
121 * be represented.
122 *
123 * 0x00000000 0x0000007F: 0xxxxxxx
124 * 0x00000000 0x000007FF: 110xxxxx 10xxxxxx
125 * 0x00000000 0x0000FFFF: 1110xxxx 10xxxxxx 10xxxxxx
126 * 0x00000000 0x001FFFFF: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
127 * 0x00000000 0x03FFFFFF: 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
128 * 0x00000000 0x7FFFFFFF: 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
129 *
130 * There is an additional requirement on UTF-8, in that only the
131 * shortest representation of a 32bit value is to be used. A decoder
132 * must not decode sequences that do not satisfy this requirement.
133 * Thus the allowed ranges have a lower bound.
134 *
135 * 0x00000000 0x0000007F: 0xxxxxxx
136 * 0x00000080 0x000007FF: 110xxxxx 10xxxxxx
137 * 0x00000800 0x0000FFFF: 1110xxxx 10xxxxxx 10xxxxxx
138 * 0x00010000 0x001FFFFF: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
139 * 0x00200000 0x03FFFFFF: 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
140 * 0x04000000 0x7FFFFFFF: 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
141 *
142 * Actual unicode characters are limited to the range 0x0 - 0x10FFFF,
143 * 17 planes of 65536 values. This limits the sequences actually seen
144 * even more, to just the following.
145 *
146 * 0 - 0x7F: 0 - 0x7F
147 * 0x80 - 0x7FF: 0xC2 0x80 - 0xDF 0xBF
148 * 0x800 - 0xFFFF: 0xE0 0xA0 0x80 - 0xEF 0xBF 0xBF
149 * 0x10000 - 0x10FFFF: 0xF0 0x90 0x80 0x80 - 0xF4 0x8F 0xBF 0xBF
150 *
151 * Within those ranges the surrogates 0xD800 - 0xDFFF are not allowed.
152 *
153 * Note that the longest sequence seen with valid usage is 4 bytes,
154 * the same a single UTF-32 character. This makes the UTF-8
155 * representation of Unicode strictly smaller than UTF-32.
156 *
157 * The shortest sequence requirement was introduced by:
158 * Corrigendum #1: UTF-8 Shortest Form
159 * It can be found here:
160 * http://www.unicode.org/versions/corrigendum1.html
161 *
162 */
163
164 /*
165 * Return the number of bytes used by the current UTF-8 sequence.
166 * Assumes the input points to the first byte of a valid UTF-8
167 * sequence.
168 */
utf8clen(const char * s)169 static inline int utf8clen(const char *s)
170 {
171 unsigned char c = *s;
172
173 return 1 + (c >= 0xC0) + (c >= 0xE0) + (c >= 0xF0);
174 }
175
176 /*
177 * Decode a 3-byte UTF-8 sequence.
178 */
179 static unsigned int
utf8decode3(const char * str)180 utf8decode3(const char *str)
181 {
182 unsigned int uc;
183
184 uc = *str++ & 0x0F;
185 uc <<= 6;
186 uc |= *str++ & 0x3F;
187 uc <<= 6;
188 uc |= *str++ & 0x3F;
189
190 return uc;
191 }
192
193 /*
194 * Encode a 3-byte UTF-8 sequence.
195 */
196 static int
utf8encode3(char * str,unsigned int val)197 utf8encode3(char *str, unsigned int val)
198 {
199 str[2] = (val & 0x3F) | 0x80;
200 val >>= 6;
201 str[1] = (val & 0x3F) | 0x80;
202 val >>= 6;
203 str[0] = val | 0xE0;
204
205 return 3;
206 }
207
208 /*
209 * utf8trie_t
210 *
211 * A compact binary tree, used to decode UTF-8 characters.
212 *
213 * Internal nodes are one byte for the node itself, and up to three
214 * bytes for an offset into the tree. The first byte contains the
215 * following information:
216 * NEXTBYTE - flag - advance to next byte if set
217 * BITNUM - 3 bit field - the bit number to tested
218 * OFFLEN - 2 bit field - number of bytes in the offset
219 * if offlen == 0 (non-branching node)
220 * RIGHTPATH - 1 bit field - set if the following node is for the
221 * right-hand path (tested bit is set)
222 * TRIENODE - 1 bit field - set if the following node is an internal
223 * node, otherwise it is a leaf node
224 * if offlen != 0 (branching node)
225 * LEFTNODE - 1 bit field - set if the left-hand node is internal
226 * RIGHTNODE - 1 bit field - set if the right-hand node is internal
227 *
228 * Due to the way utf8 works, there cannot be branching nodes with
229 * NEXTBYTE set, and moreover those nodes always have a righthand
230 * descendant.
231 */
232 typedef const unsigned char utf8trie_t;
233 #define BITNUM 0x07
234 #define NEXTBYTE 0x08
235 #define OFFLEN 0x30
236 #define OFFLEN_SHIFT 4
237 #define RIGHTPATH 0x40
238 #define TRIENODE 0x80
239 #define RIGHTNODE 0x40
240 #define LEFTNODE 0x80
241
242 /*
243 * utf8leaf_t
244 *
245 * The leaves of the trie are embedded in the trie, and so the same
246 * underlying datatype: unsigned char.
247 *
248 * leaf[0]: The unicode version, stored as a generation number that is
249 * an index into utf8agetab[]. With this we can filter code
250 * points based on the unicode version in which they were
251 * defined. The CCC of a non-defined code point is 0.
252 * leaf[1]: Canonical Combining Class. During normalization, we need
253 * to do a stable sort into ascending order of all characters
254 * with a non-zero CCC that occur between two characters with
255 * a CCC of 0, or at the begin or end of a string.
256 * The unicode standard guarantees that all CCC values are
257 * between 0 and 254 inclusive, which leaves 255 available as
258 * a special value.
259 * Code points with CCC 0 are known as stoppers.
260 * leaf[2]: Decomposition. If leaf[1] == 255, then leaf[2] is the
261 * start of a NUL-terminated string that is the decomposition
262 * of the character.
263 * The CCC of a decomposable character is the same as the CCC
264 * of the first character of its decomposition.
265 * Some characters decompose as the empty string: these are
266 * characters with the Default_Ignorable_Code_Point property.
267 * These do affect normalization, as they all have CCC 0.
268 *
269 * The decompositions in the trie have been fully expanded, with the
270 * exception of Hangul syllables, which are decomposed algorithmically.
271 *
272 * Casefolding, if applicable, is also done using decompositions.
273 *
274 * The trie is constructed in such a way that leaves exist for all
275 * UTF-8 sequences that match the criteria from the "UTF-8 valid
276 * ranges" comment above, and only for those sequences. Therefore a
277 * lookup in the trie can be used to validate the UTF-8 input.
278 */
279 typedef const unsigned char utf8leaf_t;
280
281 #define LEAF_GEN(LEAF) ((LEAF)[0])
282 #define LEAF_CCC(LEAF) ((LEAF)[1])
283 #define LEAF_STR(LEAF) ((const char *)((LEAF) + 2))
284
285 #define MINCCC (0)
286 #define MAXCCC (254)
287 #define STOPPER (0)
288 #define DECOMPOSE (255)
289
290 /* Marker for hangul syllable decomposition. */
291 #define HANGUL ((char)(255))
292 /* Size of the synthesized leaf used for Hangul syllable decomposition. */
293 #define UTF8HANGULLEAF (12)
294
295 /*
296 * Hangul decomposition (algorithm from Section 3.12 of Unicode 6.3.0)
297 *
298 * AC00;<Hangul Syllable, First>;Lo;0;L;;;;;N;;;;;
299 * D7A3;<Hangul Syllable, Last>;Lo;0;L;;;;;N;;;;;
300 *
301 * SBase = 0xAC00
302 * LBase = 0x1100
303 * VBase = 0x1161
304 * TBase = 0x11A7
305 * LCount = 19
306 * VCount = 21
307 * TCount = 28
308 * NCount = 588 (VCount * TCount)
309 * SCount = 11172 (LCount * NCount)
310 *
311 * Decomposition:
312 * SIndex = s - SBase
313 *
314 * LV (Canonical/Full)
315 * LIndex = SIndex / NCount
316 * VIndex = (Sindex % NCount) / TCount
317 * LPart = LBase + LIndex
318 * VPart = VBase + VIndex
319 *
320 * LVT (Canonical)
321 * LVIndex = (SIndex / TCount) * TCount
322 * TIndex = (Sindex % TCount)
323 * LVPart = SBase + LVIndex
324 * TPart = TBase + TIndex
325 *
326 * LVT (Full)
327 * LIndex = SIndex / NCount
328 * VIndex = (Sindex % NCount) / TCount
329 * TIndex = (Sindex % TCount)
330 * LPart = LBase + LIndex
331 * VPart = VBase + VIndex
332 * if (TIndex == 0) {
333 * d = <LPart, VPart>
334 * } else {
335 * TPart = TBase + TIndex
336 * d = <LPart, TPart, VPart>
337 * }
338 */
339
340 /* Constants */
341 #define SB (0xAC00)
342 #define LB (0x1100)
343 #define VB (0x1161)
344 #define TB (0x11A7)
345 #define LC (19)
346 #define VC (21)
347 #define TC (28)
348 #define NC (VC * TC)
349 #define SC (LC * NC)
350
351 /* Algorithmic decomposition of hangul syllable. */
352 static utf8leaf_t *
utf8hangul(const char * str,unsigned char * hangul)353 utf8hangul(const char *str, unsigned char *hangul)
354 {
355 unsigned int si;
356 unsigned int li;
357 unsigned int vi;
358 unsigned int ti;
359 unsigned char *h;
360
361 /* Calculate the SI, LI, VI, and TI values. */
362 si = utf8decode3(str) - SB;
363 li = si / NC;
364 vi = (si % NC) / TC;
365 ti = si % TC;
366
367 /* Fill in base of leaf. */
368 h = hangul;
369 LEAF_GEN(h) = 2;
370 LEAF_CCC(h) = DECOMPOSE;
371 h += 2;
372
373 /* Add LPart, a 3-byte UTF-8 sequence. */
374 h += utf8encode3((char *)h, li + LB);
375
376 /* Add VPart, a 3-byte UTF-8 sequence. */
377 h += utf8encode3((char *)h, vi + VB);
378
379 /* Add TPart if required, also a 3-byte UTF-8 sequence. */
380 if (ti)
381 h += utf8encode3((char *)h, ti + TB);
382
383 /* Terminate string. */
384 h[0] = '\0';
385
386 return hangul;
387 }
388
389 /*
390 * Use trie to scan s, touching at most len bytes.
391 * Returns the leaf if one exists, NULL otherwise.
392 *
393 * A non-NULL return guarantees that the UTF-8 sequence starting at s
394 * is well-formed and corresponds to a known unicode code point. The
395 * shorthand for this will be "is valid UTF-8 unicode".
396 */
utf8nlookup(const struct utf8data * data,unsigned char * hangul,const char * s,size_t len)397 static utf8leaf_t *utf8nlookup(const struct utf8data *data,
398 unsigned char *hangul, const char *s, size_t len)
399 {
400 utf8trie_t *trie;
401 int offlen;
402 int offset;
403 int mask;
404 int node;
405
406 if (!data)
407 return NULL;
408 if (len == 0)
409 return NULL;
410
411 trie = utf8data + data->offset;
412 node = 1;
413 while (node) {
414 offlen = (*trie & OFFLEN) >> OFFLEN_SHIFT;
415 if (*trie & NEXTBYTE) {
416 if (--len == 0)
417 return NULL;
418 s++;
419 }
420 mask = 1 << (*trie & BITNUM);
421 if (*s & mask) {
422 /* Right leg */
423 if (offlen) {
424 /* Right node at offset of trie */
425 node = (*trie & RIGHTNODE);
426 offset = trie[offlen];
427 while (--offlen) {
428 offset <<= 8;
429 offset |= trie[offlen];
430 }
431 trie += offset;
432 } else if (*trie & RIGHTPATH) {
433 /* Right node after this node */
434 node = (*trie & TRIENODE);
435 trie++;
436 } else {
437 /* No right node. */
438 return NULL;
439 }
440 } else {
441 /* Left leg */
442 if (offlen) {
443 /* Left node after this node. */
444 node = (*trie & LEFTNODE);
445 trie += offlen + 1;
446 } else if (*trie & RIGHTPATH) {
447 /* No left node. */
448 return NULL;
449 } else {
450 /* Left node after this node */
451 node = (*trie & TRIENODE);
452 trie++;
453 }
454 }
455 }
456 /*
457 * Hangul decomposition is done algorithmically. These are the
458 * codepoints >= 0xAC00 and <= 0xD7A3. Their UTF-8 encoding is
459 * always 3 bytes long, so s has been advanced twice, and the
460 * start of the sequence is at s-2.
461 */
462 if (LEAF_CCC(trie) == DECOMPOSE && LEAF_STR(trie)[0] == HANGUL)
463 trie = utf8hangul(s - 2, hangul);
464 return trie;
465 }
466
467 /*
468 * Use trie to scan s.
469 * Returns the leaf if one exists, NULL otherwise.
470 *
471 * Forwards to utf8nlookup().
472 */
utf8lookup(const struct utf8data * data,unsigned char * hangul,const char * s)473 static utf8leaf_t *utf8lookup(const struct utf8data *data,
474 unsigned char *hangul, const char *s)
475 {
476 return utf8nlookup(data, hangul, s, (size_t)-1);
477 }
478
479 #if 0
480 /*
481 * Maximum age of any character in s.
482 * Return -1 if s is not valid UTF-8 unicode.
483 * Return 0 if only non-assigned code points are used.
484 */
485 static int utf8agemax(const struct utf8data *data, const char *s)
486 {
487 utf8leaf_t *leaf;
488 int age = 0;
489 int leaf_age;
490 unsigned char hangul[UTF8HANGULLEAF];
491
492 if (!data)
493 return -1;
494
495 while (*s) {
496 leaf = utf8lookup(data, hangul, s);
497 if (!leaf)
498 return -1;
499
500 leaf_age = utf8agetab[LEAF_GEN(leaf)];
501 if (leaf_age <= data->maxage && leaf_age > age)
502 age = leaf_age;
503 s += utf8clen(s);
504 }
505 return age;
506 }
507 #endif
508
509 #if 0
510 /*
511 * Minimum age of any character in s.
512 * Return -1 if s is not valid UTF-8 unicode.
513 * Return 0 if non-assigned code points are used.
514 */
515 static int utf8agemin(const struct utf8data *data, const char *s)
516 {
517 utf8leaf_t *leaf;
518 int age;
519 int leaf_age;
520 unsigned char hangul[UTF8HANGULLEAF];
521
522 if (!data)
523 return -1;
524 age = data->maxage;
525 while (*s) {
526 leaf = utf8lookup(data, hangul, s);
527 if (!leaf)
528 return -1;
529 leaf_age = utf8agetab[LEAF_GEN(leaf)];
530 if (leaf_age <= data->maxage && leaf_age < age)
531 age = leaf_age;
532 s += utf8clen(s);
533 }
534 return age;
535 }
536 #endif
537
538 #if 0
539 /*
540 * Maximum age of any character in s, touch at most len bytes.
541 * Return -1 if s is not valid UTF-8 unicode.
542 */
543 static int utf8nagemax(const struct utf8data *data, const char *s, size_t len)
544 {
545 utf8leaf_t *leaf;
546 int age = 0;
547 int leaf_age;
548 unsigned char hangul[UTF8HANGULLEAF];
549
550 if (!data)
551 return -1;
552
553 while (len && *s) {
554 leaf = utf8nlookup(data, hangul, s, len);
555 if (!leaf)
556 return -1;
557 leaf_age = utf8agetab[LEAF_GEN(leaf)];
558 if (leaf_age <= data->maxage && leaf_age > age)
559 age = leaf_age;
560 len -= utf8clen(s);
561 s += utf8clen(s);
562 }
563 return age;
564 }
565 #endif
566
567 #if 0
568 /*
569 * Maximum age of any character in s, touch at most len bytes.
570 * Return -1 if s is not valid UTF-8 unicode.
571 */
572 static int utf8nagemin(const struct utf8data *data, const char *s, size_t len)
573 {
574 utf8leaf_t *leaf;
575 int leaf_age;
576 int age;
577 unsigned char hangul[UTF8HANGULLEAF];
578
579 if (!data)
580 return -1;
581 age = data->maxage;
582 while (len && *s) {
583 leaf = utf8nlookup(data, hangul, s, len);
584 if (!leaf)
585 return -1;
586 leaf_age = utf8agetab[LEAF_GEN(leaf)];
587 if (leaf_age <= data->maxage && leaf_age < age)
588 age = leaf_age;
589 len -= utf8clen(s);
590 s += utf8clen(s);
591 }
592 return age;
593 }
594 #endif
595
596 #if 0
597 /*
598 * Length of the normalization of s.
599 * Return -1 if s is not valid UTF-8 unicode.
600 *
601 * A string of Default_Ignorable_Code_Point has length 0.
602 */
603 static ssize_t utf8len(const struct utf8data *data, const char *s)
604 {
605 utf8leaf_t *leaf;
606 size_t ret = 0;
607 unsigned char hangul[UTF8HANGULLEAF];
608
609 if (!data)
610 return -1;
611 while (*s) {
612 leaf = utf8lookup(data, hangul, s);
613 if (!leaf)
614 return -1;
615 if (utf8agetab[LEAF_GEN(leaf)] > data->maxage)
616 ret += utf8clen(s);
617 else if (LEAF_CCC(leaf) == DECOMPOSE)
618 ret += strlen(LEAF_STR(leaf));
619 else
620 ret += utf8clen(s);
621 s += utf8clen(s);
622 }
623 return ret;
624 }
625 #endif
626
627 #if 0
628 /*
629 * Length of the normalization of s, touch at most len bytes.
630 * Return -1 if s is not valid UTF-8 unicode.
631 */
632 static ssize_t utf8nlen(const struct utf8data *data, const char *s, size_t len)
633 {
634 utf8leaf_t *leaf;
635 size_t ret = 0;
636 unsigned char hangul[UTF8HANGULLEAF];
637
638 if (!data)
639 return -1;
640 while (len && *s) {
641 leaf = utf8nlookup(data, hangul, s, len);
642 if (!leaf)
643 return -1;
644 if (utf8agetab[LEAF_GEN(leaf)] > data->maxage)
645 ret += utf8clen(s);
646 else if (LEAF_CCC(leaf) == DECOMPOSE)
647 ret += strlen(LEAF_STR(leaf));
648 else
649 ret += utf8clen(s);
650 len -= utf8clen(s);
651 s += utf8clen(s);
652 }
653 return ret;
654 }
655 #endif
656
657 /*
658 * Set up an utf8cursor for use by utf8byte().
659 *
660 * u8c : pointer to cursor.
661 * data : const struct utf8data to use for normalization.
662 * s : string.
663 * len : length of s.
664 *
665 * Returns -1 on error, 0 on success.
666 */
utf8ncursor(struct utf8cursor * u8c,const struct utf8data * data,const char * s,size_t len)667 static int utf8ncursor(struct utf8cursor *u8c, const struct utf8data *data,
668 const char *s, size_t len)
669 {
670 if (!data)
671 return -1;
672 if (!s)
673 return -1;
674 u8c->data = data;
675 u8c->s = s;
676 u8c->p = NULL;
677 u8c->ss = NULL;
678 u8c->sp = NULL;
679 u8c->len = len;
680 u8c->slen = 0;
681 u8c->ccc = STOPPER;
682 u8c->nccc = STOPPER;
683 /* Check we didn't clobber the maximum length. */
684 if (u8c->len != len)
685 return -1;
686 /* The first byte of s may not be an utf8 continuation. */
687 if (len > 0 && (*s & 0xC0) == 0x80)
688 return -1;
689 return 0;
690 }
691
692 #if 0
693 /*
694 * Set up an utf8cursor for use by utf8byte().
695 *
696 * u8c : pointer to cursor.
697 * data : const struct utf8data to use for normalization.
698 * s : NUL-terminated string.
699 *
700 * Returns -1 on error, 0 on success.
701 */
702 static int utf8cursor(struct utf8cursor *u8c, const struct utf8data *data,
703 const char *s)
704 {
705 return utf8ncursor(u8c, data, s, (unsigned int)-1);
706 }
707 #endif
708
709 /*
710 * Get one byte from the normalized form of the string described by u8c.
711 *
712 * Returns the byte cast to an unsigned char on success, and -1 on failure.
713 *
714 * The cursor keeps track of the location in the string in u8c->s.
715 * When a character is decomposed, the current location is stored in
716 * u8c->p, and u8c->s is set to the start of the decomposition. Note
717 * that bytes from a decomposition do not count against u8c->len.
718 *
719 * Characters are emitted if they match the current CCC in u8c->ccc.
720 * Hitting end-of-string while u8c->ccc == STOPPER means we're done,
721 * and the function returns 0 in that case.
722 *
723 * Sorting by CCC is done by repeatedly scanning the string. The
724 * values of u8c->s and u8c->p are stored in u8c->ss and u8c->sp at
725 * the start of the scan. The first pass finds the lowest CCC to be
726 * emitted and stores it in u8c->nccc, the second pass emits the
727 * characters with this CCC and finds the next lowest CCC. This limits
728 * the number of passes to 1 + the number of different CCCs in the
729 * sequence being scanned.
730 *
731 * Therefore:
732 * u8c->p != NULL -> a decomposition is being scanned.
733 * u8c->ss != NULL -> this is a repeating scan.
734 * u8c->ccc == -1 -> this is the first scan of a repeating scan.
735 */
utf8byte(struct utf8cursor * u8c)736 static int utf8byte(struct utf8cursor *u8c)
737 {
738 utf8leaf_t *leaf;
739 int ccc;
740
741 for (;;) {
742 /* Check for the end of a decomposed character. */
743 if (u8c->p && *u8c->s == '\0') {
744 u8c->s = u8c->p;
745 u8c->p = NULL;
746 }
747
748 /* Check for end-of-string. */
749 if (!u8c->p && (u8c->len == 0 || *u8c->s == '\0')) {
750 /* There is no next byte. */
751 if (u8c->ccc == STOPPER)
752 return 0;
753 /* End-of-string during a scan counts as a stopper. */
754 ccc = STOPPER;
755 goto ccc_mismatch;
756 } else if ((*u8c->s & 0xC0) == 0x80) {
757 /* This is a continuation of the current character. */
758 if (!u8c->p)
759 u8c->len--;
760 return (unsigned char)*u8c->s++;
761 }
762
763 /* Look up the data for the current character. */
764 if (u8c->p) {
765 leaf = utf8lookup(u8c->data, u8c->hangul, u8c->s);
766 } else {
767 leaf = utf8nlookup(u8c->data, u8c->hangul,
768 u8c->s, u8c->len);
769 }
770
771 /* No leaf found implies that the input is a binary blob. */
772 if (!leaf)
773 return -1;
774
775 ccc = LEAF_CCC(leaf);
776 /* Characters that are too new have CCC 0. */
777 if (utf8agetab[LEAF_GEN(leaf)] > u8c->data->maxage) {
778 ccc = STOPPER;
779 } else if (ccc == DECOMPOSE) {
780 u8c->len -= utf8clen(u8c->s);
781 u8c->p = u8c->s + utf8clen(u8c->s);
782 u8c->s = LEAF_STR(leaf);
783 /* Empty decomposition implies CCC 0. */
784 if (*u8c->s == '\0') {
785 if (u8c->ccc == STOPPER)
786 continue;
787 ccc = STOPPER;
788 goto ccc_mismatch;
789 }
790
791 leaf = utf8lookup(u8c->data, u8c->hangul, u8c->s);
792 if (!leaf)
793 return -1;
794 ccc = LEAF_CCC(leaf);
795 }
796
797 /*
798 * If this is not a stopper, then see if it updates
799 * the next canonical class to be emitted.
800 */
801 if (ccc != STOPPER && u8c->ccc < ccc && ccc < u8c->nccc)
802 u8c->nccc = ccc;
803
804 /*
805 * Return the current byte if this is the current
806 * combining class.
807 */
808 if (ccc == u8c->ccc) {
809 if (!u8c->p)
810 u8c->len--;
811 return (unsigned char)*u8c->s++;
812 }
813
814 /* Current combining class mismatch. */
815 ccc_mismatch:
816 if (u8c->nccc == STOPPER) {
817 /*
818 * Scan forward for the first canonical class
819 * to be emitted. Save the position from
820 * which to restart.
821 */
822 u8c->ccc = MINCCC - 1;
823 u8c->nccc = ccc;
824 u8c->sp = u8c->p;
825 u8c->ss = u8c->s;
826 u8c->slen = u8c->len;
827 if (!u8c->p)
828 u8c->len -= utf8clen(u8c->s);
829 u8c->s += utf8clen(u8c->s);
830 } else if (ccc != STOPPER) {
831 /* Not a stopper, and not the ccc we're emitting. */
832 if (!u8c->p)
833 u8c->len -= utf8clen(u8c->s);
834 u8c->s += utf8clen(u8c->s);
835 } else if (u8c->nccc != MAXCCC + 1) {
836 /* At a stopper, restart for next ccc. */
837 u8c->ccc = u8c->nccc;
838 u8c->nccc = MAXCCC + 1;
839 u8c->s = u8c->ss;
840 u8c->p = u8c->sp;
841 u8c->len = u8c->slen;
842 } else {
843 /* All done, proceed from here. */
844 u8c->ccc = STOPPER;
845 u8c->nccc = STOPPER;
846 u8c->sp = NULL;
847 u8c->ss = NULL;
848 u8c->slen = 0;
849 }
850 }
851 }
852
853 #if 0
854 /*
855 * Look for the correct const struct utf8data for a unicode version.
856 * Returns NULL if the version requested is too new.
857 *
858 * Two normalization forms are supported: nfdi and nfdicf.
859 *
860 * nfdi:
861 * - Apply unicode normalization form NFD.
862 * - Remove any Default_Ignorable_Code_Point.
863 *
864 * nfdicf:
865 * - Apply unicode normalization form NFD.
866 * - Remove any Default_Ignorable_Code_Point.
867 * - Apply a full casefold (C + F).
868 */
869 static const struct utf8data *utf8nfdi(unsigned int maxage)
870 {
871 int i = ARRAY_SIZE(utf8nfdidata) - 1;
872
873 while (maxage < utf8nfdidata[i].maxage)
874 i--;
875 if (maxage > utf8nfdidata[i].maxage)
876 return NULL;
877 return &utf8nfdidata[i];
878 }
879 #endif
880
utf8nfdicf(unsigned int maxage)881 static const struct utf8data *utf8nfdicf(unsigned int maxage)
882 {
883 int i = ARRAY_SIZE(utf8nfdicfdata) - 1;
884
885 while (maxage < utf8nfdicfdata[i].maxage)
886 i--;
887 if (maxage > utf8nfdicfdata[i].maxage)
888 return NULL;
889 return &utf8nfdicfdata[i];
890 }
891
utf8_casefold(const struct ext2fs_nls_table * table,const unsigned char * str,size_t len,unsigned char * dest,size_t dlen)892 static int utf8_casefold(const struct ext2fs_nls_table *table,
893 const unsigned char *str, size_t len,
894 unsigned char *dest, size_t dlen)
895 {
896 const struct utf8data *data = utf8nfdicf(table->version);
897 struct utf8cursor cur;
898 size_t nlen = 0;
899
900 if (utf8ncursor(&cur, data, (const char *) str, len) < 0)
901 goto invalid_seq;
902
903 for (nlen = 0; nlen < dlen; nlen++) {
904 int c = utf8byte(&cur);
905
906 dest[nlen] = c;
907 if (!c)
908 return nlen;
909 if (c == -1)
910 break;
911 }
912
913 return -ENAMETOOLONG;
914
915 invalid_seq:
916 if (dlen < len)
917 return -ENAMETOOLONG;
918
919 /* Signal invalid sequence */
920 return -EINVAL;
921 }
922
utf8_validate(const struct ext2fs_nls_table * table,char * s,size_t len,char ** pos)923 static int utf8_validate(const struct ext2fs_nls_table *table,
924 char *s, size_t len, char **pos)
925 {
926 const struct utf8data *data = utf8nfdicf(table->version);
927 utf8leaf_t *leaf;
928 unsigned char hangul[UTF8HANGULLEAF];
929
930 if (!data)
931 return -1;
932 while (len && *s) {
933 leaf = utf8nlookup(data, hangul, s, len);
934 if (!leaf) {
935 *pos = s;
936 return 1;
937 }
938 len -= utf8clen(s);
939 s += utf8clen(s);
940 }
941 return 0;
942 }
943
utf8_casefold_cmp(const struct ext2fs_nls_table * table,const unsigned char * str1,size_t len1,const unsigned char * str2,size_t len2)944 static int utf8_casefold_cmp(const struct ext2fs_nls_table *table,
945 const unsigned char *str1, size_t len1,
946 const unsigned char *str2, size_t len2)
947 {
948 const struct utf8data *data = utf8nfdicf(table->version);
949 int c1, c2;
950 struct utf8cursor cur1, cur2;
951
952 if (utf8ncursor(&cur1, data, (const char *) str1, len1) < 0)
953 return -1;
954 if (utf8ncursor(&cur2, data, (const char *) str2, len2) < 0)
955 return -1;
956
957 do {
958 c1 = utf8byte(&cur1);
959 c2 = utf8byte(&cur2);
960
961 if (c1 < 0 || c2 < 0)
962 return -1;
963 if (c1 != c2)
964 return c1 - c2;
965 } while (c1);
966
967 return 0;
968 }
969
970 static const struct ext2fs_nls_ops utf8_ops = {
971 .casefold = utf8_casefold,
972 .validate = utf8_validate,
973 .casefold_cmp = utf8_casefold_cmp,
974 };
975
976 static const struct ext2fs_nls_table nls_utf8 = {
977 .ops = &utf8_ops,
978 .version = UNICODE_AGE(12, 1, 0),
979 };
980
ext2fs_load_nls_table(int encoding)981 const struct ext2fs_nls_table *ext2fs_load_nls_table(int encoding)
982 {
983 if (encoding == EXT4_ENC_UTF8_12_1)
984 return &nls_utf8;
985
986 return NULL;
987 }
988
ext2fs_check_encoded_name(const struct ext2fs_nls_table * table,char * name,size_t len,char ** pos)989 int ext2fs_check_encoded_name(const struct ext2fs_nls_table *table,
990 char *name, size_t len, char **pos)
991 {
992 return table->ops->validate(table, name, len, pos);
993 }
994
ext2fs_casefold_cmp(const struct ext2fs_nls_table * table,const unsigned char * str1,size_t len1,const unsigned char * str2,size_t len2)995 int ext2fs_casefold_cmp(const struct ext2fs_nls_table *table,
996 const unsigned char *str1, size_t len1,
997 const unsigned char *str2, size_t len2)
998 {
999 return table->ops->casefold_cmp(table, str1, len1, str2, len2);
1000 }
1001