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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * linux/lib/string.c | |
4 | * | |
5 | * Copyright (C) 1991, 1992 Linus Torvalds | |
6 | */ | |
7 | ||
8 | /* | |
cfecea6e KC |
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.) | |
1da177e4 | 13 | * |
cfecea6e | 14 | * Other helper functions should live in string_helpers.c. |
1da177e4 LT |
15 | */ |
16 | ||
cfecea6e | 17 | #define __NO_FORTIFY |
1da177e4 LT |
18 | #include <linux/types.h> |
19 | #include <linux/string.h> | |
20 | #include <linux/ctype.h> | |
8bc3bcc9 PG |
21 | #include <linux/kernel.h> |
22 | #include <linux/export.h> | |
50af5ead | 23 | #include <linux/bug.h> |
8bc3bcc9 | 24 | #include <linux/errno.h> |
ce76d938 | 25 | #include <linux/slab.h> |
1da177e4 | 26 | |
291d47cc | 27 | #include <asm/unaligned.h> |
30035e45 CM |
28 | #include <asm/byteorder.h> |
29 | #include <asm/word-at-a-time.h> | |
30 | #include <asm/page.h> | |
31 | ||
cd514e72 | 32 | #ifndef __HAVE_ARCH_STRNCASECMP |
1da177e4 | 33 | /** |
cd514e72 | 34 | * strncasecmp - Case insensitive, length-limited string comparison |
1da177e4 LT |
35 | * @s1: One string |
36 | * @s2: The other string | |
37 | * @len: the maximum number of characters to compare | |
38 | */ | |
cd514e72 | 39 | int strncasecmp(const char *s1, const char *s2, size_t len) |
1da177e4 LT |
40 | { |
41 | /* Yes, Virginia, it had better be unsigned */ | |
42 | unsigned char c1, c2; | |
43 | ||
a11d2b64 AGR |
44 | if (!len) |
45 | return 0; | |
46 | ||
47 | do { | |
48 | c1 = *s1++; | |
49 | c2 = *s2++; | |
50 | if (!c1 || !c2) | |
51 | break; | |
52 | if (c1 == c2) | |
53 | continue; | |
54 | c1 = tolower(c1); | |
55 | c2 = tolower(c2); | |
56 | if (c1 != c2) | |
57 | break; | |
58 | } while (--len); | |
1da177e4 LT |
59 | return (int)c1 - (int)c2; |
60 | } | |
cd514e72 RV |
61 | EXPORT_SYMBOL(strncasecmp); |
62 | #endif | |
1da177e4 | 63 | |
ded220bd DM |
64 | #ifndef __HAVE_ARCH_STRCASECMP |
65 | int strcasecmp(const char *s1, const char *s2) | |
66 | { | |
67 | int c1, c2; | |
68 | ||
69 | do { | |
70 | c1 = tolower(*s1++); | |
71 | c2 = tolower(*s2++); | |
72 | } while (c1 == c2 && c1 != 0); | |
73 | return c1 - c2; | |
74 | } | |
75 | EXPORT_SYMBOL(strcasecmp); | |
76 | #endif | |
77 | ||
1da177e4 | 78 | #ifndef __HAVE_ARCH_STRCPY |
51a0f0f6 | 79 | char *strcpy(char *dest, const char *src) |
1da177e4 LT |
80 | { |
81 | char *tmp = dest; | |
82 | ||
83 | while ((*dest++ = *src++) != '\0') | |
84 | /* nothing */; | |
85 | return tmp; | |
86 | } | |
87 | EXPORT_SYMBOL(strcpy); | |
88 | #endif | |
89 | ||
90 | #ifndef __HAVE_ARCH_STRNCPY | |
51a0f0f6 | 91 | char *strncpy(char *dest, const char *src, size_t count) |
1da177e4 LT |
92 | { |
93 | char *tmp = dest; | |
94 | ||
95 | while (count) { | |
51a0f0f6 JJ |
96 | if ((*tmp = *src) != 0) |
97 | src++; | |
1da177e4 LT |
98 | tmp++; |
99 | count--; | |
100 | } | |
101 | return dest; | |
102 | } | |
103 | EXPORT_SYMBOL(strncpy); | |
104 | #endif | |
105 | ||
106 | #ifndef __HAVE_ARCH_STRLCPY | |
1da177e4 LT |
107 | size_t strlcpy(char *dest, const char *src, size_t size) |
108 | { | |
109 | size_t ret = strlen(src); | |
110 | ||
111 | if (size) { | |
51a0f0f6 | 112 | size_t len = (ret >= size) ? size - 1 : ret; |
1da177e4 LT |
113 | memcpy(dest, src, len); |
114 | dest[len] = '\0'; | |
115 | } | |
116 | return ret; | |
117 | } | |
118 | EXPORT_SYMBOL(strlcpy); | |
119 | #endif | |
120 | ||
30035e45 | 121 | #ifndef __HAVE_ARCH_STRSCPY |
30035e45 CM |
122 | ssize_t strscpy(char *dest, const char *src, size_t count) |
123 | { | |
124 | const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; | |
125 | size_t max = count; | |
126 | long res = 0; | |
127 | ||
9a156466 | 128 | if (count == 0 || WARN_ON_ONCE(count > INT_MAX)) |
30035e45 CM |
129 | return -E2BIG; |
130 | ||
131 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS | |
132 | /* | |
133 | * If src is unaligned, don't cross a page boundary, | |
134 | * since we don't know if the next page is mapped. | |
135 | */ | |
136 | if ((long)src & (sizeof(long) - 1)) { | |
137 | size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1)); | |
138 | if (limit < max) | |
139 | max = limit; | |
140 | } | |
141 | #else | |
142 | /* If src or dest is unaligned, don't do word-at-a-time. */ | |
143 | if (((long) dest | (long) src) & (sizeof(long) - 1)) | |
144 | max = 0; | |
145 | #endif | |
146 | ||
2de6f3bf AP |
147 | /* |
148 | * read_word_at_a_time() below may read uninitialized bytes after the | |
149 | * trailing zero and use them in comparisons. Disable this optimization | |
150 | * under KMSAN to prevent false positive reports. | |
151 | */ | |
152 | if (IS_ENABLED(CONFIG_KMSAN)) | |
153 | max = 0; | |
154 | ||
30035e45 CM |
155 | while (max >= sizeof(unsigned long)) { |
156 | unsigned long c, data; | |
157 | ||
1a3241ff | 158 | c = read_word_at_a_time(src+res); |
30035e45 CM |
159 | if (has_zero(c, &data, &constants)) { |
160 | data = prep_zero_mask(c, data, &constants); | |
161 | data = create_zero_mask(data); | |
990486c8 | 162 | *(unsigned long *)(dest+res) = c & zero_bytemask(data); |
30035e45 CM |
163 | return res + find_zero(data); |
164 | } | |
990486c8 | 165 | *(unsigned long *)(dest+res) = c; |
30035e45 CM |
166 | res += sizeof(unsigned long); |
167 | count -= sizeof(unsigned long); | |
168 | max -= sizeof(unsigned long); | |
169 | } | |
170 | ||
171 | while (count) { | |
172 | char c; | |
173 | ||
174 | c = src[res]; | |
175 | dest[res] = c; | |
176 | if (!c) | |
177 | return res; | |
178 | res++; | |
179 | count--; | |
180 | } | |
181 | ||
182 | /* Hit buffer length without finding a NUL; force NUL-termination. */ | |
183 | if (res) | |
184 | dest[res-1] = '\0'; | |
185 | ||
186 | return -E2BIG; | |
187 | } | |
188 | EXPORT_SYMBOL(strscpy); | |
189 | #endif | |
190 | ||
1e1b6d63 ND |
191 | /** |
192 | * stpcpy - copy a string from src to dest returning a pointer to the new end | |
193 | * of dest, including src's %NUL-terminator. May overrun dest. | |
194 | * @dest: pointer to end of string being copied into. Must be large enough | |
195 | * to receive copy. | |
196 | * @src: pointer to the beginning of string being copied from. Must not overlap | |
197 | * dest. | |
198 | * | |
199 | * stpcpy differs from strcpy in a key way: the return value is a pointer | |
200 | * to the new %NUL-terminating character in @dest. (For strcpy, the return | |
201 | * value is a pointer to the start of @dest). This interface is considered | |
202 | * unsafe as it doesn't perform bounds checking of the inputs. As such it's | |
203 | * not recommended for usage. Instead, its definition is provided in case | |
204 | * the compiler lowers other libcalls to stpcpy. | |
205 | */ | |
206 | char *stpcpy(char *__restrict__ dest, const char *__restrict__ src); | |
207 | char *stpcpy(char *__restrict__ dest, const char *__restrict__ src) | |
208 | { | |
209 | while ((*dest++ = *src++) != '\0') | |
210 | /* nothing */; | |
211 | return --dest; | |
212 | } | |
213 | EXPORT_SYMBOL(stpcpy); | |
214 | ||
1da177e4 | 215 | #ifndef __HAVE_ARCH_STRCAT |
51a0f0f6 | 216 | char *strcat(char *dest, const char *src) |
1da177e4 LT |
217 | { |
218 | char *tmp = dest; | |
219 | ||
220 | while (*dest) | |
221 | dest++; | |
222 | while ((*dest++ = *src++) != '\0') | |
223 | ; | |
1da177e4 LT |
224 | return tmp; |
225 | } | |
226 | EXPORT_SYMBOL(strcat); | |
227 | #endif | |
228 | ||
229 | #ifndef __HAVE_ARCH_STRNCAT | |
51a0f0f6 | 230 | char *strncat(char *dest, const char *src, size_t count) |
1da177e4 LT |
231 | { |
232 | char *tmp = dest; | |
233 | ||
234 | if (count) { | |
235 | while (*dest) | |
236 | dest++; | |
237 | while ((*dest++ = *src++) != 0) { | |
238 | if (--count == 0) { | |
239 | *dest = '\0'; | |
240 | break; | |
241 | } | |
242 | } | |
243 | } | |
1da177e4 LT |
244 | return tmp; |
245 | } | |
246 | EXPORT_SYMBOL(strncat); | |
247 | #endif | |
248 | ||
249 | #ifndef __HAVE_ARCH_STRLCAT | |
1da177e4 LT |
250 | size_t strlcat(char *dest, const char *src, size_t count) |
251 | { | |
252 | size_t dsize = strlen(dest); | |
253 | size_t len = strlen(src); | |
254 | size_t res = dsize + len; | |
255 | ||
256 | /* This would be a bug */ | |
257 | BUG_ON(dsize >= count); | |
258 | ||
259 | dest += dsize; | |
260 | count -= dsize; | |
261 | if (len >= count) | |
262 | len = count-1; | |
263 | memcpy(dest, src, len); | |
264 | dest[len] = 0; | |
265 | return res; | |
266 | } | |
267 | EXPORT_SYMBOL(strlcat); | |
268 | #endif | |
269 | ||
270 | #ifndef __HAVE_ARCH_STRCMP | |
271 | /** | |
272 | * strcmp - Compare two strings | |
273 | * @cs: One string | |
274 | * @ct: Another string | |
275 | */ | |
51a0f0f6 | 276 | int strcmp(const char *cs, const char *ct) |
1da177e4 | 277 | { |
a414f01a | 278 | unsigned char c1, c2; |
1da177e4 LT |
279 | |
280 | while (1) { | |
a414f01a LT |
281 | c1 = *cs++; |
282 | c2 = *ct++; | |
283 | if (c1 != c2) | |
284 | return c1 < c2 ? -1 : 1; | |
285 | if (!c1) | |
1da177e4 LT |
286 | break; |
287 | } | |
a414f01a | 288 | return 0; |
1da177e4 LT |
289 | } |
290 | EXPORT_SYMBOL(strcmp); | |
291 | #endif | |
292 | ||
293 | #ifndef __HAVE_ARCH_STRNCMP | |
294 | /** | |
295 | * strncmp - Compare two length-limited strings | |
296 | * @cs: One string | |
297 | * @ct: Another string | |
298 | * @count: The maximum number of bytes to compare | |
299 | */ | |
51a0f0f6 | 300 | int strncmp(const char *cs, const char *ct, size_t count) |
1da177e4 | 301 | { |
a414f01a | 302 | unsigned char c1, c2; |
1da177e4 LT |
303 | |
304 | while (count) { | |
a414f01a LT |
305 | c1 = *cs++; |
306 | c2 = *ct++; | |
307 | if (c1 != c2) | |
308 | return c1 < c2 ? -1 : 1; | |
309 | if (!c1) | |
1da177e4 LT |
310 | break; |
311 | count--; | |
312 | } | |
a414f01a | 313 | return 0; |
1da177e4 LT |
314 | } |
315 | EXPORT_SYMBOL(strncmp); | |
316 | #endif | |
317 | ||
318 | #ifndef __HAVE_ARCH_STRCHR | |
319 | /** | |
320 | * strchr - Find the first occurrence of a character in a string | |
321 | * @s: The string to be searched | |
322 | * @c: The character to search for | |
b0975710 PR |
323 | * |
324 | * Note that the %NUL-terminator is considered part of the string, and can | |
325 | * be searched for. | |
1da177e4 | 326 | */ |
51a0f0f6 | 327 | char *strchr(const char *s, int c) |
1da177e4 | 328 | { |
51a0f0f6 | 329 | for (; *s != (char)c; ++s) |
1da177e4 LT |
330 | if (*s == '\0') |
331 | return NULL; | |
51a0f0f6 | 332 | return (char *)s; |
1da177e4 LT |
333 | } |
334 | EXPORT_SYMBOL(strchr); | |
335 | #endif | |
336 | ||
11d200e9 GL |
337 | #ifndef __HAVE_ARCH_STRCHRNUL |
338 | /** | |
339 | * strchrnul - Find and return a character in a string, or end of string | |
340 | * @s: The string to be searched | |
341 | * @c: The character to search for | |
342 | * | |
343 | * Returns pointer to first occurrence of 'c' in s. If c is not found, then | |
344 | * return a pointer to the null byte at the end of s. | |
345 | */ | |
346 | char *strchrnul(const char *s, int c) | |
347 | { | |
348 | while (*s && *s != (char)c) | |
349 | s++; | |
350 | return (char *)s; | |
351 | } | |
352 | EXPORT_SYMBOL(strchrnul); | |
353 | #endif | |
354 | ||
0bee0cec YN |
355 | /** |
356 | * strnchrnul - Find and return a character in a length limited string, | |
357 | * or end of string | |
358 | * @s: The string to be searched | |
359 | * @count: The number of characters to be searched | |
360 | * @c: The character to search for | |
361 | * | |
362 | * Returns pointer to the first occurrence of 'c' in s. If c is not found, | |
363 | * then return a pointer to the last character of the string. | |
364 | */ | |
365 | char *strnchrnul(const char *s, size_t count, int c) | |
366 | { | |
367 | while (count-- && *s && *s != (char)c) | |
368 | s++; | |
369 | return (char *)s; | |
370 | } | |
371 | ||
1da177e4 LT |
372 | #ifndef __HAVE_ARCH_STRRCHR |
373 | /** | |
374 | * strrchr - Find the last occurrence of a character in a string | |
375 | * @s: The string to be searched | |
376 | * @c: The character to search for | |
377 | */ | |
51a0f0f6 | 378 | char *strrchr(const char *s, int c) |
1da177e4 | 379 | { |
8da53d45 RV |
380 | const char *last = NULL; |
381 | do { | |
382 | if (*s == (char)c) | |
383 | last = s; | |
384 | } while (*s++); | |
385 | return (char *)last; | |
1da177e4 LT |
386 | } |
387 | EXPORT_SYMBOL(strrchr); | |
388 | #endif | |
389 | ||
390 | #ifndef __HAVE_ARCH_STRNCHR | |
391 | /** | |
392 | * strnchr - Find a character in a length limited string | |
393 | * @s: The string to be searched | |
394 | * @count: The number of characters to be searched | |
395 | * @c: The character to search for | |
b0975710 PR |
396 | * |
397 | * Note that the %NUL-terminator is considered part of the string, and can | |
398 | * be searched for. | |
1da177e4 LT |
399 | */ |
400 | char *strnchr(const char *s, size_t count, int c) | |
401 | { | |
b0975710 | 402 | while (count--) { |
51a0f0f6 JJ |
403 | if (*s == (char)c) |
404 | return (char *)s; | |
b0975710 PR |
405 | if (*s++ == '\0') |
406 | break; | |
407 | } | |
1da177e4 LT |
408 | return NULL; |
409 | } | |
410 | EXPORT_SYMBOL(strnchr); | |
411 | #endif | |
412 | ||
413 | #ifndef __HAVE_ARCH_STRLEN | |
51a0f0f6 | 414 | size_t strlen(const char *s) |
1da177e4 LT |
415 | { |
416 | const char *sc; | |
417 | ||
418 | for (sc = s; *sc != '\0'; ++sc) | |
419 | /* nothing */; | |
420 | return sc - s; | |
421 | } | |
422 | EXPORT_SYMBOL(strlen); | |
423 | #endif | |
424 | ||
425 | #ifndef __HAVE_ARCH_STRNLEN | |
51a0f0f6 | 426 | size_t strnlen(const char *s, size_t count) |
1da177e4 LT |
427 | { |
428 | const char *sc; | |
429 | ||
430 | for (sc = s; count-- && *sc != '\0'; ++sc) | |
431 | /* nothing */; | |
432 | return sc - s; | |
433 | } | |
434 | EXPORT_SYMBOL(strnlen); | |
435 | #endif | |
436 | ||
437 | #ifndef __HAVE_ARCH_STRSPN | |
438 | /** | |
72fd4a35 | 439 | * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept |
1da177e4 LT |
440 | * @s: The string to be searched |
441 | * @accept: The string to search for | |
442 | */ | |
443 | size_t strspn(const char *s, const char *accept) | |
444 | { | |
445 | const char *p; | |
1da177e4 LT |
446 | |
447 | for (p = s; *p != '\0'; ++p) { | |
dffad91b RV |
448 | if (!strchr(accept, *p)) |
449 | break; | |
1da177e4 | 450 | } |
dffad91b | 451 | return p - s; |
1da177e4 | 452 | } |
1da177e4 LT |
453 | EXPORT_SYMBOL(strspn); |
454 | #endif | |
455 | ||
8833d328 | 456 | #ifndef __HAVE_ARCH_STRCSPN |
1da177e4 | 457 | /** |
72fd4a35 | 458 | * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject |
1da177e4 LT |
459 | * @s: The string to be searched |
460 | * @reject: The string to avoid | |
461 | */ | |
462 | size_t strcspn(const char *s, const char *reject) | |
463 | { | |
464 | const char *p; | |
1da177e4 LT |
465 | |
466 | for (p = s; *p != '\0'; ++p) { | |
dffad91b RV |
467 | if (strchr(reject, *p)) |
468 | break; | |
1da177e4 | 469 | } |
dffad91b | 470 | return p - s; |
51a0f0f6 | 471 | } |
1da177e4 | 472 | EXPORT_SYMBOL(strcspn); |
8833d328 | 473 | #endif |
1da177e4 LT |
474 | |
475 | #ifndef __HAVE_ARCH_STRPBRK | |
476 | /** | |
477 | * strpbrk - Find the first occurrence of a set of characters | |
478 | * @cs: The string to be searched | |
479 | * @ct: The characters to search for | |
480 | */ | |
51a0f0f6 | 481 | char *strpbrk(const char *cs, const char *ct) |
1da177e4 | 482 | { |
51a0f0f6 | 483 | const char *sc1, *sc2; |
1da177e4 | 484 | |
51a0f0f6 JJ |
485 | for (sc1 = cs; *sc1 != '\0'; ++sc1) { |
486 | for (sc2 = ct; *sc2 != '\0'; ++sc2) { | |
1da177e4 | 487 | if (*sc1 == *sc2) |
51a0f0f6 | 488 | return (char *)sc1; |
1da177e4 LT |
489 | } |
490 | } | |
491 | return NULL; | |
492 | } | |
894b5779 | 493 | EXPORT_SYMBOL(strpbrk); |
1da177e4 LT |
494 | #endif |
495 | ||
496 | #ifndef __HAVE_ARCH_STRSEP | |
497 | /** | |
498 | * strsep - Split a string into tokens | |
499 | * @s: The string to be searched | |
500 | * @ct: The characters to search for | |
501 | * | |
502 | * strsep() updates @s to point after the token, ready for the next call. | |
503 | * | |
504 | * It returns empty tokens, too, behaving exactly like the libc function | |
505 | * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. | |
506 | * Same semantics, slimmer shape. ;) | |
507 | */ | |
51a0f0f6 | 508 | char *strsep(char **s, const char *ct) |
1da177e4 | 509 | { |
51a0f0f6 JJ |
510 | char *sbegin = *s; |
511 | char *end; | |
1da177e4 LT |
512 | |
513 | if (sbegin == NULL) | |
514 | return NULL; | |
515 | ||
516 | end = strpbrk(sbegin, ct); | |
517 | if (end) | |
518 | *end++ = '\0'; | |
519 | *s = end; | |
1da177e4 LT |
520 | return sbegin; |
521 | } | |
1da177e4 LT |
522 | EXPORT_SYMBOL(strsep); |
523 | #endif | |
524 | ||
525 | #ifndef __HAVE_ARCH_MEMSET | |
526 | /** | |
527 | * memset - Fill a region of memory with the given value | |
528 | * @s: Pointer to the start of the area. | |
529 | * @c: The byte to fill the area with | |
530 | * @count: The size of the area. | |
531 | * | |
532 | * Do not use memset() to access IO space, use memset_io() instead. | |
533 | */ | |
51a0f0f6 | 534 | void *memset(void *s, int c, size_t count) |
1da177e4 | 535 | { |
850b9247 | 536 | char *xs = s; |
1da177e4 LT |
537 | |
538 | while (count--) | |
539 | *xs++ = c; | |
1da177e4 LT |
540 | return s; |
541 | } | |
542 | EXPORT_SYMBOL(memset); | |
543 | #endif | |
544 | ||
3b3c4bab MW |
545 | #ifndef __HAVE_ARCH_MEMSET16 |
546 | /** | |
547 | * memset16() - Fill a memory area with a uint16_t | |
548 | * @s: Pointer to the start of the area. | |
549 | * @v: The value to fill the area with | |
550 | * @count: The number of values to store | |
551 | * | |
552 | * Differs from memset() in that it fills with a uint16_t instead | |
553 | * of a byte. Remember that @count is the number of uint16_ts to | |
554 | * store, not the number of bytes. | |
555 | */ | |
556 | void *memset16(uint16_t *s, uint16_t v, size_t count) | |
557 | { | |
558 | uint16_t *xs = s; | |
559 | ||
560 | while (count--) | |
561 | *xs++ = v; | |
562 | return s; | |
563 | } | |
564 | EXPORT_SYMBOL(memset16); | |
565 | #endif | |
566 | ||
567 | #ifndef __HAVE_ARCH_MEMSET32 | |
568 | /** | |
569 | * memset32() - Fill a memory area with a uint32_t | |
570 | * @s: Pointer to the start of the area. | |
571 | * @v: The value to fill the area with | |
572 | * @count: The number of values to store | |
573 | * | |
574 | * Differs from memset() in that it fills with a uint32_t instead | |
575 | * of a byte. Remember that @count is the number of uint32_ts to | |
576 | * store, not the number of bytes. | |
577 | */ | |
578 | void *memset32(uint32_t *s, uint32_t v, size_t count) | |
579 | { | |
580 | uint32_t *xs = s; | |
581 | ||
582 | while (count--) | |
583 | *xs++ = v; | |
584 | return s; | |
585 | } | |
586 | EXPORT_SYMBOL(memset32); | |
587 | #endif | |
588 | ||
589 | #ifndef __HAVE_ARCH_MEMSET64 | |
590 | /** | |
591 | * memset64() - Fill a memory area with a uint64_t | |
592 | * @s: Pointer to the start of the area. | |
593 | * @v: The value to fill the area with | |
594 | * @count: The number of values to store | |
595 | * | |
596 | * Differs from memset() in that it fills with a uint64_t instead | |
597 | * of a byte. Remember that @count is the number of uint64_ts to | |
598 | * store, not the number of bytes. | |
599 | */ | |
600 | void *memset64(uint64_t *s, uint64_t v, size_t count) | |
601 | { | |
602 | uint64_t *xs = s; | |
603 | ||
604 | while (count--) | |
605 | *xs++ = v; | |
606 | return s; | |
607 | } | |
608 | EXPORT_SYMBOL(memset64); | |
609 | #endif | |
610 | ||
1da177e4 LT |
611 | #ifndef __HAVE_ARCH_MEMCPY |
612 | /** | |
613 | * memcpy - Copy one area of memory to another | |
614 | * @dest: Where to copy to | |
615 | * @src: Where to copy from | |
616 | * @count: The size of the area. | |
617 | * | |
618 | * You should not use this function to access IO space, use memcpy_toio() | |
619 | * or memcpy_fromio() instead. | |
620 | */ | |
51a0f0f6 | 621 | void *memcpy(void *dest, const void *src, size_t count) |
1da177e4 | 622 | { |
850b9247 | 623 | char *tmp = dest; |
4c416ab7 | 624 | const char *s = src; |
1da177e4 LT |
625 | |
626 | while (count--) | |
627 | *tmp++ = *s++; | |
1da177e4 LT |
628 | return dest; |
629 | } | |
630 | EXPORT_SYMBOL(memcpy); | |
631 | #endif | |
632 | ||
633 | #ifndef __HAVE_ARCH_MEMMOVE | |
634 | /** | |
635 | * memmove - Copy one area of memory to another | |
636 | * @dest: Where to copy to | |
637 | * @src: Where to copy from | |
638 | * @count: The size of the area. | |
639 | * | |
640 | * Unlike memcpy(), memmove() copes with overlapping areas. | |
641 | */ | |
51a0f0f6 | 642 | void *memmove(void *dest, const void *src, size_t count) |
1da177e4 | 643 | { |
82da2c37 PJ |
644 | char *tmp; |
645 | const char *s; | |
1da177e4 LT |
646 | |
647 | if (dest <= src) { | |
850b9247 JJ |
648 | tmp = dest; |
649 | s = src; | |
1da177e4 LT |
650 | while (count--) |
651 | *tmp++ = *s++; | |
51a0f0f6 | 652 | } else { |
850b9247 JJ |
653 | tmp = dest; |
654 | tmp += count; | |
655 | s = src; | |
656 | s += count; | |
1da177e4 LT |
657 | while (count--) |
658 | *--tmp = *--s; | |
51a0f0f6 | 659 | } |
1da177e4 LT |
660 | return dest; |
661 | } | |
662 | EXPORT_SYMBOL(memmove); | |
663 | #endif | |
664 | ||
665 | #ifndef __HAVE_ARCH_MEMCMP | |
666 | /** | |
667 | * memcmp - Compare two areas of memory | |
668 | * @cs: One area of memory | |
669 | * @ct: Another area of memory | |
670 | * @count: The size of the area. | |
671 | */ | |
0c28130b | 672 | #undef memcmp |
a7330c99 | 673 | __visible int memcmp(const void *cs, const void *ct, size_t count) |
1da177e4 LT |
674 | { |
675 | const unsigned char *su1, *su2; | |
676 | int res = 0; | |
677 | ||
291d47cc LT |
678 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS |
679 | if (count >= sizeof(unsigned long)) { | |
680 | const unsigned long *u1 = cs; | |
681 | const unsigned long *u2 = ct; | |
682 | do { | |
683 | if (get_unaligned(u1) != get_unaligned(u2)) | |
684 | break; | |
685 | u1++; | |
686 | u2++; | |
687 | count -= sizeof(unsigned long); | |
688 | } while (count >= sizeof(unsigned long)); | |
689 | cs = u1; | |
690 | ct = u2; | |
691 | } | |
692 | #endif | |
51a0f0f6 | 693 | for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) |
1da177e4 LT |
694 | if ((res = *su1 - *su2) != 0) |
695 | break; | |
696 | return res; | |
697 | } | |
698 | EXPORT_SYMBOL(memcmp); | |
699 | #endif | |
700 | ||
5f074f3e ND |
701 | #ifndef __HAVE_ARCH_BCMP |
702 | /** | |
703 | * bcmp - returns 0 if and only if the buffers have identical contents. | |
704 | * @a: pointer to first buffer. | |
705 | * @b: pointer to second buffer. | |
706 | * @len: size of buffers. | |
707 | * | |
708 | * The sign or magnitude of a non-zero return value has no particular | |
709 | * meaning, and architectures may implement their own more efficient bcmp(). So | |
710 | * while this particular implementation is a simple (tail) call to memcmp, do | |
711 | * not rely on anything but whether the return value is zero or non-zero. | |
712 | */ | |
5f074f3e ND |
713 | int bcmp(const void *a, const void *b, size_t len) |
714 | { | |
715 | return memcmp(a, b, len); | |
716 | } | |
717 | EXPORT_SYMBOL(bcmp); | |
718 | #endif | |
719 | ||
1da177e4 LT |
720 | #ifndef __HAVE_ARCH_MEMSCAN |
721 | /** | |
722 | * memscan - Find a character in an area of memory. | |
723 | * @addr: The memory area | |
724 | * @c: The byte to search for | |
725 | * @size: The size of the area. | |
726 | * | |
727 | * returns the address of the first occurrence of @c, or 1 byte past | |
728 | * the area if @c is not found | |
729 | */ | |
51a0f0f6 | 730 | void *memscan(void *addr, int c, size_t size) |
1da177e4 | 731 | { |
850b9247 | 732 | unsigned char *p = addr; |
1da177e4 LT |
733 | |
734 | while (size) { | |
1a58be62 | 735 | if (*p == (unsigned char)c) |
51a0f0f6 | 736 | return (void *)p; |
1da177e4 LT |
737 | p++; |
738 | size--; | |
739 | } | |
51a0f0f6 | 740 | return (void *)p; |
1da177e4 LT |
741 | } |
742 | EXPORT_SYMBOL(memscan); | |
743 | #endif | |
744 | ||
745 | #ifndef __HAVE_ARCH_STRSTR | |
746 | /** | |
747 | * strstr - Find the first substring in a %NUL terminated string | |
748 | * @s1: The string to be searched | |
749 | * @s2: The string to search for | |
750 | */ | |
51a0f0f6 | 751 | char *strstr(const char *s1, const char *s2) |
1da177e4 | 752 | { |
d5f1fb53 | 753 | size_t l1, l2; |
1da177e4 LT |
754 | |
755 | l2 = strlen(s2); | |
756 | if (!l2) | |
51a0f0f6 | 757 | return (char *)s1; |
1da177e4 LT |
758 | l1 = strlen(s1); |
759 | while (l1 >= l2) { | |
760 | l1--; | |
51a0f0f6 JJ |
761 | if (!memcmp(s1, s2, l2)) |
762 | return (char *)s1; | |
1da177e4 LT |
763 | s1++; |
764 | } | |
765 | return NULL; | |
766 | } | |
767 | EXPORT_SYMBOL(strstr); | |
768 | #endif | |
769 | ||
d5f1fb53 LZ |
770 | #ifndef __HAVE_ARCH_STRNSTR |
771 | /** | |
772 | * strnstr - Find the first substring in a length-limited string | |
773 | * @s1: The string to be searched | |
774 | * @s2: The string to search for | |
775 | * @len: the maximum number of characters to search | |
776 | */ | |
777 | char *strnstr(const char *s1, const char *s2, size_t len) | |
778 | { | |
d6a2eedf | 779 | size_t l2; |
d5f1fb53 LZ |
780 | |
781 | l2 = strlen(s2); | |
782 | if (!l2) | |
783 | return (char *)s1; | |
d6a2eedf AGR |
784 | while (len >= l2) { |
785 | len--; | |
d5f1fb53 LZ |
786 | if (!memcmp(s1, s2, l2)) |
787 | return (char *)s1; | |
788 | s1++; | |
789 | } | |
790 | return NULL; | |
791 | } | |
792 | EXPORT_SYMBOL(strnstr); | |
793 | #endif | |
794 | ||
1da177e4 LT |
795 | #ifndef __HAVE_ARCH_MEMCHR |
796 | /** | |
797 | * memchr - Find a character in an area of memory. | |
798 | * @s: The memory area | |
799 | * @c: The byte to search for | |
800 | * @n: The size of the area. | |
801 | * | |
802 | * returns the address of the first occurrence of @c, or %NULL | |
803 | * if @c is not found | |
804 | */ | |
805 | void *memchr(const void *s, int c, size_t n) | |
806 | { | |
807 | const unsigned char *p = s; | |
808 | while (n-- != 0) { | |
809 | if ((unsigned char)c == *p++) { | |
51a0f0f6 | 810 | return (void *)(p - 1); |
1da177e4 LT |
811 | } |
812 | } | |
813 | return NULL; | |
814 | } | |
815 | EXPORT_SYMBOL(memchr); | |
816 | #endif | |
79824820 AM |
817 | |
818 | static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) | |
819 | { | |
820 | while (bytes) { | |
821 | if (*start != value) | |
822 | return (void *)start; | |
823 | start++; | |
824 | bytes--; | |
825 | } | |
826 | return NULL; | |
827 | } | |
828 | ||
829 | /** | |
830 | * memchr_inv - Find an unmatching character in an area of memory. | |
831 | * @start: The memory area | |
832 | * @c: Find a character other than c | |
833 | * @bytes: The size of the area. | |
834 | * | |
835 | * returns the address of the first character other than @c, or %NULL | |
836 | * if the whole buffer contains just @c. | |
837 | */ | |
838 | void *memchr_inv(const void *start, int c, size_t bytes) | |
839 | { | |
840 | u8 value = c; | |
841 | u64 value64; | |
842 | unsigned int words, prefix; | |
843 | ||
844 | if (bytes <= 16) | |
845 | return check_bytes8(start, value, bytes); | |
846 | ||
f43804bf | 847 | value64 = value; |
72d93104 | 848 | #if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 |
3368e8fb | 849 | value64 *= 0x0101010101010101ULL; |
72d93104 | 850 | #elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) |
f43804bf AM |
851 | value64 *= 0x01010101; |
852 | value64 |= value64 << 32; | |
853 | #else | |
854 | value64 |= value64 << 8; | |
855 | value64 |= value64 << 16; | |
856 | value64 |= value64 << 32; | |
857 | #endif | |
79824820 | 858 | |
f43804bf | 859 | prefix = (unsigned long)start % 8; |
79824820 | 860 | if (prefix) { |
f43804bf AM |
861 | u8 *r; |
862 | ||
863 | prefix = 8 - prefix; | |
864 | r = check_bytes8(start, value, prefix); | |
79824820 AM |
865 | if (r) |
866 | return r; | |
867 | start += prefix; | |
868 | bytes -= prefix; | |
869 | } | |
870 | ||
871 | words = bytes / 8; | |
872 | ||
873 | while (words) { | |
874 | if (*(u64 *)start != value64) | |
875 | return check_bytes8(start, value, 8); | |
876 | start += 8; | |
877 | words--; | |
878 | } | |
879 | ||
880 | return check_bytes8(start, value, bytes % 8); | |
881 | } | |
882 | EXPORT_SYMBOL(memchr_inv); |