Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * linux/lib/string.c
4 : *
5 : * Copyright (C) 1991, 1992 Linus Torvalds
6 : */
7 :
8 : /*
9 : * This file should be used only for "library" routines that may have
10 : * alternative implementations on specific architectures (generally
11 : * found in <asm-xx/string.h>), or get overloaded by FORTIFY_SOURCE.
12 : * (Specifically, this file is built with __NO_FORTIFY.)
13 : *
14 : * Other helper functions should live in string_helpers.c.
15 : */
16 :
17 : #define __NO_FORTIFY
18 : #include <linux/types.h>
19 : #include <linux/string.h>
20 : #include <linux/ctype.h>
21 : #include <linux/kernel.h>
22 : #include <linux/export.h>
23 : #include <linux/bug.h>
24 : #include <linux/errno.h>
25 : #include <linux/slab.h>
26 :
27 : #include <asm/unaligned.h>
28 : #include <asm/byteorder.h>
29 : #include <asm/word-at-a-time.h>
30 : #include <asm/page.h>
31 :
32 : #ifndef __HAVE_ARCH_STRNCASECMP
33 : /**
34 : * strncasecmp - Case insensitive, length-limited string comparison
35 : * @s1: One string
36 : * @s2: The other string
37 : * @len: the maximum number of characters to compare
38 : */
39 0 : int strncasecmp(const char *s1, const char *s2, size_t len)
40 : {
41 : /* Yes, Virginia, it had better be unsigned */
42 : unsigned char c1, c2;
43 :
44 0 : if (!len)
45 : return 0;
46 :
47 : do {
48 0 : c1 = *s1++;
49 0 : c2 = *s2++;
50 0 : if (!c1 || !c2)
51 : break;
52 0 : if (c1 == c2)
53 0 : continue;
54 0 : c1 = tolower(c1);
55 0 : c2 = tolower(c2);
56 0 : if (c1 != c2)
57 : break;
58 0 : } while (--len);
59 0 : return (int)c1 - (int)c2;
60 : }
61 : EXPORT_SYMBOL(strncasecmp);
62 : #endif
63 :
64 : #ifndef __HAVE_ARCH_STRCASECMP
65 0 : int strcasecmp(const char *s1, const char *s2)
66 : {
67 : int c1, c2;
68 :
69 : do {
70 0 : c1 = tolower(*s1++);
71 0 : c2 = tolower(*s2++);
72 0 : } while (c1 == c2 && c1 != 0);
73 0 : return c1 - c2;
74 : }
75 : EXPORT_SYMBOL(strcasecmp);
76 : #endif
77 :
78 : #ifndef __HAVE_ARCH_STRCPY
79 : /**
80 : * strcpy - Copy a %NUL terminated string
81 : * @dest: Where to copy the string to
82 : * @src: Where to copy the string from
83 : */
84 120 : char *strcpy(char *dest, const char *src)
85 : {
86 120 : char *tmp = dest;
87 :
88 120 : while ((*dest++ = *src++) != '\0')
89 : /* nothing */;
90 120 : return tmp;
91 : }
92 : EXPORT_SYMBOL(strcpy);
93 : #endif
94 :
95 : #ifndef __HAVE_ARCH_STRNCPY
96 : /**
97 : * strncpy - Copy a length-limited, C-string
98 : * @dest: Where to copy the string to
99 : * @src: Where to copy the string from
100 : * @count: The maximum number of bytes to copy
101 : *
102 : * The result is not %NUL-terminated if the source exceeds
103 : * @count bytes.
104 : *
105 : * In the case where the length of @src is less than that of
106 : * count, the remainder of @dest will be padded with %NUL.
107 : *
108 : */
109 1 : char *strncpy(char *dest, const char *src, size_t count)
110 : {
111 1 : char *tmp = dest;
112 :
113 21 : while (count) {
114 19 : if ((*tmp = *src) != 0)
115 3 : src++;
116 19 : tmp++;
117 19 : count--;
118 : }
119 1 : return dest;
120 : }
121 : EXPORT_SYMBOL(strncpy);
122 : #endif
123 :
124 : #ifndef __HAVE_ARCH_STRLCPY
125 : /**
126 : * strlcpy - Copy a C-string into a sized buffer
127 : * @dest: Where to copy the string to
128 : * @src: Where to copy the string from
129 : * @size: size of destination buffer
130 : *
131 : * Compatible with ``*BSD``: the result is always a valid
132 : * NUL-terminated string that fits in the buffer (unless,
133 : * of course, the buffer size is zero). It does not pad
134 : * out the result like strncpy() does.
135 : */
136 136 : size_t strlcpy(char *dest, const char *src, size_t size)
137 : {
138 136 : size_t ret = strlen(src);
139 :
140 136 : if (size) {
141 136 : size_t len = (ret >= size) ? size - 1 : ret;
142 136 : memcpy(dest, src, len);
143 136 : dest[len] = '\0';
144 : }
145 136 : return ret;
146 : }
147 : EXPORT_SYMBOL(strlcpy);
148 : #endif
149 :
150 : #ifndef __HAVE_ARCH_STRSCPY
151 : /**
152 : * strscpy - Copy a C-string into a sized buffer
153 : * @dest: Where to copy the string to
154 : * @src: Where to copy the string from
155 : * @count: Size of destination buffer
156 : *
157 : * Copy the string, or as much of it as fits, into the dest buffer. The
158 : * behavior is undefined if the string buffers overlap. The destination
159 : * buffer is always NUL terminated, unless it's zero-sized.
160 : *
161 : * Preferred to strlcpy() since the API doesn't require reading memory
162 : * from the src string beyond the specified "count" bytes, and since
163 : * the return value is easier to error-check than strlcpy()'s.
164 : * In addition, the implementation is robust to the string changing out
165 : * from underneath it, unlike the current strlcpy() implementation.
166 : *
167 : * Preferred to strncpy() since it always returns a valid string, and
168 : * doesn't unnecessarily force the tail of the destination buffer to be
169 : * zeroed. If zeroing is desired please use strscpy_pad().
170 : *
171 : * Returns:
172 : * * The number of characters copied (not including the trailing %NUL)
173 : * * -E2BIG if count is 0 or @src was truncated.
174 : */
175 112 : ssize_t strscpy(char *dest, const char *src, size_t count)
176 : {
177 112 : const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
178 112 : size_t max = count;
179 112 : long res = 0;
180 :
181 112 : if (count == 0 || WARN_ON_ONCE(count > INT_MAX))
182 : return -E2BIG;
183 :
184 : #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
185 : /*
186 : * If src is unaligned, don't cross a page boundary,
187 : * since we don't know if the next page is mapped.
188 : */
189 : if ((long)src & (sizeof(long) - 1)) {
190 : size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1));
191 : if (limit < max)
192 : max = limit;
193 : }
194 : #else
195 : /* If src or dest is unaligned, don't do word-at-a-time. */
196 112 : if (((long) dest | (long) src) & (sizeof(long) - 1))
197 7 : max = 0;
198 : #endif
199 :
200 215 : while (max >= sizeof(unsigned long)) {
201 : unsigned long c, data;
202 :
203 416 : c = read_word_at_a_time(src+res);
204 208 : if (has_zero(c, &data, &constants)) {
205 105 : data = prep_zero_mask(c, data, &constants);
206 210 : data = create_zero_mask(data);
207 105 : *(unsigned long *)(dest+res) = c & zero_bytemask(data);
208 210 : return res + find_zero(data);
209 : }
210 103 : *(unsigned long *)(dest+res) = c;
211 103 : res += sizeof(unsigned long);
212 103 : count -= sizeof(unsigned long);
213 103 : max -= sizeof(unsigned long);
214 : }
215 :
216 88 : while (count) {
217 : char c;
218 :
219 88 : c = src[res];
220 88 : dest[res] = c;
221 88 : if (!c)
222 : return res;
223 81 : res++;
224 81 : count--;
225 : }
226 :
227 : /* Hit buffer length without finding a NUL; force NUL-termination. */
228 0 : if (res)
229 0 : dest[res-1] = '\0';
230 :
231 : return -E2BIG;
232 : }
233 : EXPORT_SYMBOL(strscpy);
234 : #endif
235 :
236 : /**
237 : * stpcpy - copy a string from src to dest returning a pointer to the new end
238 : * of dest, including src's %NUL-terminator. May overrun dest.
239 : * @dest: pointer to end of string being copied into. Must be large enough
240 : * to receive copy.
241 : * @src: pointer to the beginning of string being copied from. Must not overlap
242 : * dest.
243 : *
244 : * stpcpy differs from strcpy in a key way: the return value is a pointer
245 : * to the new %NUL-terminating character in @dest. (For strcpy, the return
246 : * value is a pointer to the start of @dest). This interface is considered
247 : * unsafe as it doesn't perform bounds checking of the inputs. As such it's
248 : * not recommended for usage. Instead, its definition is provided in case
249 : * the compiler lowers other libcalls to stpcpy.
250 : */
251 : char *stpcpy(char *__restrict__ dest, const char *__restrict__ src);
252 0 : char *stpcpy(char *__restrict__ dest, const char *__restrict__ src)
253 : {
254 0 : while ((*dest++ = *src++) != '\0')
255 : /* nothing */;
256 0 : return --dest;
257 : }
258 : EXPORT_SYMBOL(stpcpy);
259 :
260 : #ifndef __HAVE_ARCH_STRCAT
261 : /**
262 : * strcat - Append one %NUL-terminated string to another
263 : * @dest: The string to be appended to
264 : * @src: The string to append to it
265 : */
266 35 : char *strcat(char *dest, const char *src)
267 : {
268 35 : char *tmp = dest;
269 :
270 705 : while (*dest)
271 635 : dest++;
272 275 : while ((*dest++ = *src++) != '\0')
273 : ;
274 35 : return tmp;
275 : }
276 : EXPORT_SYMBOL(strcat);
277 : #endif
278 :
279 : #ifndef __HAVE_ARCH_STRNCAT
280 : /**
281 : * strncat - Append a length-limited, C-string to another
282 : * @dest: The string to be appended to
283 : * @src: The string to append to it
284 : * @count: The maximum numbers of bytes to copy
285 : *
286 : * Note that in contrast to strncpy(), strncat() ensures the result is
287 : * terminated.
288 : */
289 0 : char *strncat(char *dest, const char *src, size_t count)
290 : {
291 0 : char *tmp = dest;
292 :
293 0 : if (count) {
294 0 : while (*dest)
295 0 : dest++;
296 0 : while ((*dest++ = *src++) != 0) {
297 0 : if (--count == 0) {
298 0 : *dest = '\0';
299 0 : break;
300 : }
301 : }
302 : }
303 0 : return tmp;
304 : }
305 : EXPORT_SYMBOL(strncat);
306 : #endif
307 :
308 : #ifndef __HAVE_ARCH_STRLCAT
309 : /**
310 : * strlcat - Append a length-limited, C-string to another
311 : * @dest: The string to be appended to
312 : * @src: The string to append to it
313 : * @count: The size of the destination buffer.
314 : */
315 42 : size_t strlcat(char *dest, const char *src, size_t count)
316 : {
317 42 : size_t dsize = strlen(dest);
318 42 : size_t len = strlen(src);
319 42 : size_t res = dsize + len;
320 :
321 : /* This would be a bug */
322 42 : BUG_ON(dsize >= count);
323 :
324 42 : dest += dsize;
325 42 : count -= dsize;
326 42 : if (len >= count)
327 0 : len = count-1;
328 42 : memcpy(dest, src, len);
329 42 : dest[len] = 0;
330 42 : return res;
331 : }
332 : EXPORT_SYMBOL(strlcat);
333 : #endif
334 :
335 : #ifndef __HAVE_ARCH_STRCMP
336 : /**
337 : * strcmp - Compare two strings
338 : * @cs: One string
339 : * @ct: Another string
340 : */
341 5662 : int strcmp(const char *cs, const char *ct)
342 : {
343 : unsigned char c1, c2;
344 :
345 : while (1) {
346 36521 : c1 = *cs++;
347 36521 : c2 = *ct++;
348 36521 : if (c1 != c2)
349 1910 : return c1 < c2 ? -1 : 1;
350 34611 : if (!c1)
351 : break;
352 : }
353 : return 0;
354 : }
355 : EXPORT_SYMBOL(strcmp);
356 : #endif
357 :
358 : #ifndef __HAVE_ARCH_STRNCMP
359 : /**
360 : * strncmp - Compare two length-limited strings
361 : * @cs: One string
362 : * @ct: Another string
363 : * @count: The maximum number of bytes to compare
364 : */
365 315 : int strncmp(const char *cs, const char *ct, size_t count)
366 : {
367 : unsigned char c1, c2;
368 :
369 779 : while (count) {
370 435 : c1 = *cs++;
371 435 : c2 = *ct++;
372 435 : if (c1 != c2)
373 286 : return c1 < c2 ? -1 : 1;
374 149 : if (!c1)
375 : break;
376 149 : count--;
377 : }
378 : return 0;
379 : }
380 : EXPORT_SYMBOL(strncmp);
381 : #endif
382 :
383 : #ifndef __HAVE_ARCH_STRCHR
384 : /**
385 : * strchr - Find the first occurrence of a character in a string
386 : * @s: The string to be searched
387 : * @c: The character to search for
388 : *
389 : * Note that the %NUL-terminator is considered part of the string, and can
390 : * be searched for.
391 : */
392 2320 : char *strchr(const char *s, int c)
393 : {
394 11203 : for (; *s != (char)c; ++s)
395 10370 : if (*s == '\0')
396 : return NULL;
397 : return (char *)s;
398 : }
399 : EXPORT_SYMBOL(strchr);
400 : #endif
401 :
402 : #ifndef __HAVE_ARCH_STRCHRNUL
403 : /**
404 : * strchrnul - Find and return a character in a string, or end of string
405 : * @s: The string to be searched
406 : * @c: The character to search for
407 : *
408 : * Returns pointer to first occurrence of 'c' in s. If c is not found, then
409 : * return a pointer to the null byte at the end of s.
410 : */
411 0 : char *strchrnul(const char *s, int c)
412 : {
413 0 : while (*s && *s != (char)c)
414 0 : s++;
415 0 : return (char *)s;
416 : }
417 : EXPORT_SYMBOL(strchrnul);
418 : #endif
419 :
420 : /**
421 : * strnchrnul - Find and return a character in a length limited string,
422 : * or end of string
423 : * @s: The string to be searched
424 : * @count: The number of characters to be searched
425 : * @c: The character to search for
426 : *
427 : * Returns pointer to the first occurrence of 'c' in s. If c is not found,
428 : * then return a pointer to the last character of the string.
429 : */
430 0 : char *strnchrnul(const char *s, size_t count, int c)
431 : {
432 0 : while (count-- && *s && *s != (char)c)
433 0 : s++;
434 0 : return (char *)s;
435 : }
436 :
437 : #ifndef __HAVE_ARCH_STRRCHR
438 : /**
439 : * strrchr - Find the last occurrence of a character in a string
440 : * @s: The string to be searched
441 : * @c: The character to search for
442 : */
443 0 : char *strrchr(const char *s, int c)
444 : {
445 0 : const char *last = NULL;
446 : do {
447 0 : if (*s == (char)c)
448 0 : last = s;
449 0 : } while (*s++);
450 0 : return (char *)last;
451 : }
452 : EXPORT_SYMBOL(strrchr);
453 : #endif
454 :
455 : #ifndef __HAVE_ARCH_STRNCHR
456 : /**
457 : * strnchr - Find a character in a length limited string
458 : * @s: The string to be searched
459 : * @count: The number of characters to be searched
460 : * @c: The character to search for
461 : *
462 : * Note that the %NUL-terminator is considered part of the string, and can
463 : * be searched for.
464 : */
465 1 : char *strnchr(const char *s, size_t count, int c)
466 : {
467 5 : while (count--) {
468 3 : if (*s == (char)c)
469 : return (char *)s;
470 3 : if (*s++ == '\0')
471 : break;
472 : }
473 : return NULL;
474 : }
475 : EXPORT_SYMBOL(strnchr);
476 : #endif
477 :
478 : #ifndef __HAVE_ARCH_STRLEN
479 : /**
480 : * strlen - Find the length of a string
481 : * @s: The string to be sized
482 : */
483 32777 : size_t strlen(const char *s)
484 : {
485 : const char *sc;
486 :
487 295752 : for (sc = s; *sc != '\0'; ++sc)
488 : /* nothing */;
489 34177 : return sc - s;
490 : }
491 : EXPORT_SYMBOL(strlen);
492 : #endif
493 :
494 : #ifndef __HAVE_ARCH_STRNLEN
495 : /**
496 : * strnlen - Find the length of a length-limited string
497 : * @s: The string to be sized
498 : * @count: The maximum number of bytes to search
499 : */
500 0 : size_t strnlen(const char *s, size_t count)
501 : {
502 : const char *sc;
503 :
504 0 : for (sc = s; count-- && *sc != '\0'; ++sc)
505 : /* nothing */;
506 0 : return sc - s;
507 : }
508 : EXPORT_SYMBOL(strnlen);
509 : #endif
510 :
511 : #ifndef __HAVE_ARCH_STRSPN
512 : /**
513 : * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
514 : * @s: The string to be searched
515 : * @accept: The string to search for
516 : */
517 0 : size_t strspn(const char *s, const char *accept)
518 : {
519 : const char *p;
520 : const char *a;
521 0 : size_t count = 0;
522 :
523 0 : for (p = s; *p != '\0'; ++p) {
524 0 : for (a = accept; *a != '\0'; ++a) {
525 0 : if (*p == *a)
526 : break;
527 : }
528 0 : if (*a == '\0')
529 : return count;
530 0 : ++count;
531 : }
532 : return count;
533 : }
534 :
535 : EXPORT_SYMBOL(strspn);
536 : #endif
537 :
538 : #ifndef __HAVE_ARCH_STRCSPN
539 : /**
540 : * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
541 : * @s: The string to be searched
542 : * @reject: The string to avoid
543 : */
544 1 : size_t strcspn(const char *s, const char *reject)
545 : {
546 : const char *p;
547 : const char *r;
548 1 : size_t count = 0;
549 :
550 3 : for (p = s; *p != '\0'; ++p) {
551 2 : for (r = reject; *r != '\0'; ++r) {
552 3 : if (*p == *r)
553 : return count;
554 : }
555 2 : ++count;
556 : }
557 : return count;
558 : }
559 : EXPORT_SYMBOL(strcspn);
560 : #endif
561 :
562 : #ifndef __HAVE_ARCH_STRPBRK
563 : /**
564 : * strpbrk - Find the first occurrence of a set of characters
565 : * @cs: The string to be searched
566 : * @ct: The characters to search for
567 : */
568 0 : char *strpbrk(const char *cs, const char *ct)
569 : {
570 : const char *sc1, *sc2;
571 :
572 0 : for (sc1 = cs; *sc1 != '\0'; ++sc1) {
573 0 : for (sc2 = ct; *sc2 != '\0'; ++sc2) {
574 0 : if (*sc1 == *sc2)
575 : return (char *)sc1;
576 : }
577 : }
578 : return NULL;
579 : }
580 : EXPORT_SYMBOL(strpbrk);
581 : #endif
582 :
583 : #ifndef __HAVE_ARCH_STRSEP
584 : /**
585 : * strsep - Split a string into tokens
586 : * @s: The string to be searched
587 : * @ct: The characters to search for
588 : *
589 : * strsep() updates @s to point after the token, ready for the next call.
590 : *
591 : * It returns empty tokens, too, behaving exactly like the libc function
592 : * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
593 : * Same semantics, slimmer shape. ;)
594 : */
595 0 : char *strsep(char **s, const char *ct)
596 : {
597 0 : char *sbegin = *s;
598 : char *end;
599 :
600 0 : if (sbegin == NULL)
601 : return NULL;
602 :
603 0 : end = strpbrk(sbegin, ct);
604 0 : if (end)
605 0 : *end++ = '\0';
606 0 : *s = end;
607 0 : return sbegin;
608 : }
609 : EXPORT_SYMBOL(strsep);
610 : #endif
611 :
612 : #ifndef __HAVE_ARCH_MEMSET
613 : /**
614 : * memset - Fill a region of memory with the given value
615 : * @s: Pointer to the start of the area.
616 : * @c: The byte to fill the area with
617 : * @count: The size of the area.
618 : *
619 : * Do not use memset() to access IO space, use memset_io() instead.
620 : */
621 : void *memset(void *s, int c, size_t count)
622 : {
623 : char *xs = s;
624 :
625 : while (count--)
626 : *xs++ = c;
627 : return s;
628 : }
629 : EXPORT_SYMBOL(memset);
630 : #endif
631 :
632 : #ifndef __HAVE_ARCH_MEMSET16
633 : /**
634 : * memset16() - Fill a memory area with a uint16_t
635 : * @s: Pointer to the start of the area.
636 : * @v: The value to fill the area with
637 : * @count: The number of values to store
638 : *
639 : * Differs from memset() in that it fills with a uint16_t instead
640 : * of a byte. Remember that @count is the number of uint16_ts to
641 : * store, not the number of bytes.
642 : */
643 : void *memset16(uint16_t *s, uint16_t v, size_t count)
644 : {
645 : uint16_t *xs = s;
646 :
647 : while (count--)
648 : *xs++ = v;
649 : return s;
650 : }
651 : EXPORT_SYMBOL(memset16);
652 : #endif
653 :
654 : #ifndef __HAVE_ARCH_MEMSET32
655 : /**
656 : * memset32() - Fill a memory area with a uint32_t
657 : * @s: Pointer to the start of the area.
658 : * @v: The value to fill the area with
659 : * @count: The number of values to store
660 : *
661 : * Differs from memset() in that it fills with a uint32_t instead
662 : * of a byte. Remember that @count is the number of uint32_ts to
663 : * store, not the number of bytes.
664 : */
665 : void *memset32(uint32_t *s, uint32_t v, size_t count)
666 : {
667 : uint32_t *xs = s;
668 :
669 : while (count--)
670 : *xs++ = v;
671 : return s;
672 : }
673 : EXPORT_SYMBOL(memset32);
674 : #endif
675 :
676 : #ifndef __HAVE_ARCH_MEMSET64
677 : /**
678 : * memset64() - Fill a memory area with a uint64_t
679 : * @s: Pointer to the start of the area.
680 : * @v: The value to fill the area with
681 : * @count: The number of values to store
682 : *
683 : * Differs from memset() in that it fills with a uint64_t instead
684 : * of a byte. Remember that @count is the number of uint64_ts to
685 : * store, not the number of bytes.
686 : */
687 : void *memset64(uint64_t *s, uint64_t v, size_t count)
688 : {
689 : uint64_t *xs = s;
690 :
691 : while (count--)
692 : *xs++ = v;
693 : return s;
694 : }
695 : EXPORT_SYMBOL(memset64);
696 : #endif
697 :
698 : #ifndef __HAVE_ARCH_MEMCPY
699 : /**
700 : * memcpy - Copy one area of memory to another
701 : * @dest: Where to copy to
702 : * @src: Where to copy from
703 : * @count: The size of the area.
704 : *
705 : * You should not use this function to access IO space, use memcpy_toio()
706 : * or memcpy_fromio() instead.
707 : */
708 : void *memcpy(void *dest, const void *src, size_t count)
709 : {
710 : char *tmp = dest;
711 : const char *s = src;
712 :
713 : while (count--)
714 : *tmp++ = *s++;
715 : return dest;
716 : }
717 : EXPORT_SYMBOL(memcpy);
718 : #endif
719 :
720 : #ifndef __HAVE_ARCH_MEMMOVE
721 : /**
722 : * memmove - Copy one area of memory to another
723 : * @dest: Where to copy to
724 : * @src: Where to copy from
725 : * @count: The size of the area.
726 : *
727 : * Unlike memcpy(), memmove() copes with overlapping areas.
728 : */
729 : void *memmove(void *dest, const void *src, size_t count)
730 : {
731 : char *tmp;
732 : const char *s;
733 :
734 : if (dest <= src) {
735 : tmp = dest;
736 : s = src;
737 : while (count--)
738 : *tmp++ = *s++;
739 : } else {
740 : tmp = dest;
741 : tmp += count;
742 : s = src;
743 : s += count;
744 : while (count--)
745 : *--tmp = *--s;
746 : }
747 : return dest;
748 : }
749 : EXPORT_SYMBOL(memmove);
750 : #endif
751 :
752 : #ifndef __HAVE_ARCH_MEMCMP
753 : /**
754 : * memcmp - Compare two areas of memory
755 : * @cs: One area of memory
756 : * @ct: Another area of memory
757 : * @count: The size of the area.
758 : */
759 : #undef memcmp
760 1590 : __visible int memcmp(const void *cs, const void *ct, size_t count)
761 : {
762 : const unsigned char *su1, *su2;
763 203742 : int res = 0;
764 :
765 : #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
766 : if (count >= sizeof(unsigned long)) {
767 : const unsigned long *u1 = cs;
768 : const unsigned long *u2 = ct;
769 : do {
770 : if (get_unaligned(u1) != get_unaligned(u2))
771 : break;
772 : u1++;
773 : u2++;
774 : count -= sizeof(unsigned long);
775 : } while (count >= sizeof(unsigned long));
776 : cs = u1;
777 : ct = u2;
778 : }
779 : #endif
780 224953 : for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
781 224251 : if ((res = *su1 - *su2) != 0)
782 : break;
783 1590 : return res;
784 : }
785 : EXPORT_SYMBOL(memcmp);
786 : #endif
787 :
788 : #ifndef __HAVE_ARCH_BCMP
789 : /**
790 : * bcmp - returns 0 if and only if the buffers have identical contents.
791 : * @a: pointer to first buffer.
792 : * @b: pointer to second buffer.
793 : * @len: size of buffers.
794 : *
795 : * The sign or magnitude of a non-zero return value has no particular
796 : * meaning, and architectures may implement their own more efficient bcmp(). So
797 : * while this particular implementation is a simple (tail) call to memcmp, do
798 : * not rely on anything but whether the return value is zero or non-zero.
799 : */
800 0 : int bcmp(const void *a, const void *b, size_t len)
801 : {
802 0 : return memcmp(a, b, len);
803 : }
804 : EXPORT_SYMBOL(bcmp);
805 : #endif
806 :
807 : #ifndef __HAVE_ARCH_MEMSCAN
808 : /**
809 : * memscan - Find a character in an area of memory.
810 : * @addr: The memory area
811 : * @c: The byte to search for
812 : * @size: The size of the area.
813 : *
814 : * returns the address of the first occurrence of @c, or 1 byte past
815 : * the area if @c is not found
816 : */
817 0 : void *memscan(void *addr, int c, size_t size)
818 : {
819 0 : unsigned char *p = addr;
820 :
821 0 : while (size) {
822 0 : if (*p == (unsigned char)c)
823 : return (void *)p;
824 0 : p++;
825 0 : size--;
826 : }
827 : return (void *)p;
828 : }
829 : EXPORT_SYMBOL(memscan);
830 : #endif
831 :
832 : #ifndef __HAVE_ARCH_STRSTR
833 : /**
834 : * strstr - Find the first substring in a %NUL terminated string
835 : * @s1: The string to be searched
836 : * @s2: The string to search for
837 : */
838 590 : char *strstr(const char *s1, const char *s2)
839 : {
840 : size_t l1, l2;
841 :
842 590 : l2 = strlen(s2);
843 590 : if (!l2)
844 : return (char *)s1;
845 590 : l1 = strlen(s1);
846 203196 : while (l1 >= l2) {
847 202152 : l1--;
848 202152 : if (!memcmp(s1, s2, l2))
849 : return (char *)s1;
850 202016 : s1++;
851 : }
852 : return NULL;
853 : }
854 : EXPORT_SYMBOL(strstr);
855 : #endif
856 :
857 : #ifndef __HAVE_ARCH_STRNSTR
858 : /**
859 : * strnstr - Find the first substring in a length-limited string
860 : * @s1: The string to be searched
861 : * @s2: The string to search for
862 : * @len: the maximum number of characters to search
863 : */
864 0 : char *strnstr(const char *s1, const char *s2, size_t len)
865 : {
866 : size_t l2;
867 :
868 0 : l2 = strlen(s2);
869 0 : if (!l2)
870 : return (char *)s1;
871 0 : while (len >= l2) {
872 0 : len--;
873 0 : if (!memcmp(s1, s2, l2))
874 : return (char *)s1;
875 0 : s1++;
876 : }
877 : return NULL;
878 : }
879 : EXPORT_SYMBOL(strnstr);
880 : #endif
881 :
882 : #ifndef __HAVE_ARCH_MEMCHR
883 : /**
884 : * memchr - Find a character in an area of memory.
885 : * @s: The memory area
886 : * @c: The byte to search for
887 : * @n: The size of the area.
888 : *
889 : * returns the address of the first occurrence of @c, or %NULL
890 : * if @c is not found
891 : */
892 407 : void *memchr(const void *s, int c, size_t n)
893 : {
894 407 : const unsigned char *p = s;
895 22710 : while (n-- != 0) {
896 21926 : if ((unsigned char)c == *p++) {
897 : return (void *)(p - 1);
898 : }
899 : }
900 : return NULL;
901 : }
902 : EXPORT_SYMBOL(memchr);
903 : #endif
904 :
905 : static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
906 : {
907 0 : while (bytes) {
908 0 : if (*start != value)
909 : return (void *)start;
910 0 : start++;
911 0 : bytes--;
912 : }
913 : return NULL;
914 : }
915 :
916 : /**
917 : * memchr_inv - Find an unmatching character in an area of memory.
918 : * @start: The memory area
919 : * @c: Find a character other than c
920 : * @bytes: The size of the area.
921 : *
922 : * returns the address of the first character other than @c, or %NULL
923 : * if the whole buffer contains just @c.
924 : */
925 0 : void *memchr_inv(const void *start, int c, size_t bytes)
926 : {
927 0 : u8 value = c;
928 : u64 value64;
929 : unsigned int words, prefix;
930 :
931 0 : if (bytes <= 16)
932 0 : return check_bytes8(start, value, bytes);
933 :
934 0 : value64 = value;
935 : #if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64
936 : value64 *= 0x0101010101010101ULL;
937 : #elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER)
938 : value64 *= 0x01010101;
939 : value64 |= value64 << 32;
940 : #else
941 0 : value64 |= value64 << 8;
942 0 : value64 |= value64 << 16;
943 0 : value64 |= value64 << 32;
944 : #endif
945 :
946 0 : prefix = (unsigned long)start % 8;
947 0 : if (prefix) {
948 : u8 *r;
949 :
950 0 : prefix = 8 - prefix;
951 0 : r = check_bytes8(start, value, prefix);
952 0 : if (r)
953 : return r;
954 0 : start += prefix;
955 0 : bytes -= prefix;
956 : }
957 :
958 0 : words = bytes / 8;
959 :
960 0 : while (words) {
961 0 : if (*(u64 *)start != value64)
962 : return check_bytes8(start, value, 8);
963 0 : start += 8;
964 0 : words--;
965 : }
966 :
967 0 : return check_bytes8(start, value, bytes % 8);
968 : }
969 : EXPORT_SYMBOL(memchr_inv);
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