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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 |
38b9baf1 | 18 | #include <linux/bits.h> |
50af5ead | 19 | #include <linux/bug.h> |
38b9baf1 | 20 | #include <linux/ctype.h> |
8bc3bcc9 | 21 | #include <linux/errno.h> |
38b9baf1 TH |
22 | #include <linux/limits.h> |
23 | #include <linux/linkage.h> | |
24 | #include <linux/stddef.h> | |
25 | #include <linux/string.h> | |
26 | #include <linux/types.h> | |
1da177e4 | 27 | |
38b9baf1 TH |
28 | #include <asm/page.h> |
29 | #include <asm/rwonce.h> | |
291d47cc | 30 | #include <asm/unaligned.h> |
30035e45 | 31 | #include <asm/word-at-a-time.h> |
30035e45 | 32 | |
cd514e72 | 33 | #ifndef __HAVE_ARCH_STRNCASECMP |
1da177e4 | 34 | /** |
cd514e72 | 35 | * strncasecmp - Case insensitive, length-limited string comparison |
1da177e4 LT |
36 | * @s1: One string |
37 | * @s2: The other string | |
38 | * @len: the maximum number of characters to compare | |
39 | */ | |
cd514e72 | 40 | int strncasecmp(const char *s1, const char *s2, size_t len) |
1da177e4 LT |
41 | { |
42 | /* Yes, Virginia, it had better be unsigned */ | |
43 | unsigned char c1, c2; | |
44 | ||
a11d2b64 AGR |
45 | if (!len) |
46 | return 0; | |
47 | ||
48 | do { | |
49 | c1 = *s1++; | |
50 | c2 = *s2++; | |
51 | if (!c1 || !c2) | |
52 | break; | |
53 | if (c1 == c2) | |
54 | continue; | |
55 | c1 = tolower(c1); | |
56 | c2 = tolower(c2); | |
57 | if (c1 != c2) | |
58 | break; | |
59 | } while (--len); | |
1da177e4 LT |
60 | return (int)c1 - (int)c2; |
61 | } | |
cd514e72 RV |
62 | EXPORT_SYMBOL(strncasecmp); |
63 | #endif | |
1da177e4 | 64 | |
ded220bd DM |
65 | #ifndef __HAVE_ARCH_STRCASECMP |
66 | int strcasecmp(const char *s1, const char *s2) | |
67 | { | |
68 | int c1, c2; | |
69 | ||
70 | do { | |
71 | c1 = tolower(*s1++); | |
72 | c2 = tolower(*s2++); | |
73 | } while (c1 == c2 && c1 != 0); | |
74 | return c1 - c2; | |
75 | } | |
76 | EXPORT_SYMBOL(strcasecmp); | |
77 | #endif | |
78 | ||
1da177e4 | 79 | #ifndef __HAVE_ARCH_STRCPY |
51a0f0f6 | 80 | char *strcpy(char *dest, const char *src) |
1da177e4 LT |
81 | { |
82 | char *tmp = dest; | |
83 | ||
84 | while ((*dest++ = *src++) != '\0') | |
85 | /* nothing */; | |
86 | return tmp; | |
87 | } | |
88 | EXPORT_SYMBOL(strcpy); | |
89 | #endif | |
90 | ||
91 | #ifndef __HAVE_ARCH_STRNCPY | |
51a0f0f6 | 92 | char *strncpy(char *dest, const char *src, size_t count) |
1da177e4 LT |
93 | { |
94 | char *tmp = dest; | |
95 | ||
96 | while (count) { | |
51a0f0f6 JJ |
97 | if ((*tmp = *src) != 0) |
98 | src++; | |
1da177e4 LT |
99 | tmp++; |
100 | count--; | |
101 | } | |
102 | return dest; | |
103 | } | |
104 | EXPORT_SYMBOL(strncpy); | |
105 | #endif | |
106 | ||
e6584c39 | 107 | ssize_t sized_strscpy(char *dest, const char *src, size_t count) |
30035e45 CM |
108 | { |
109 | const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; | |
110 | size_t max = count; | |
111 | long res = 0; | |
112 | ||
9a156466 | 113 | if (count == 0 || WARN_ON_ONCE(count > INT_MAX)) |
30035e45 CM |
114 | return -E2BIG; |
115 | ||
116 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS | |
117 | /* | |
118 | * If src is unaligned, don't cross a page boundary, | |
119 | * since we don't know if the next page is mapped. | |
120 | */ | |
121 | if ((long)src & (sizeof(long) - 1)) { | |
122 | size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1)); | |
123 | if (limit < max) | |
124 | max = limit; | |
125 | } | |
126 | #else | |
127 | /* If src or dest is unaligned, don't do word-at-a-time. */ | |
128 | if (((long) dest | (long) src) & (sizeof(long) - 1)) | |
129 | max = 0; | |
130 | #endif | |
131 | ||
2de6f3bf AP |
132 | /* |
133 | * read_word_at_a_time() below may read uninitialized bytes after the | |
134 | * trailing zero and use them in comparisons. Disable this optimization | |
135 | * under KMSAN to prevent false positive reports. | |
136 | */ | |
137 | if (IS_ENABLED(CONFIG_KMSAN)) | |
138 | max = 0; | |
139 | ||
30035e45 CM |
140 | while (max >= sizeof(unsigned long)) { |
141 | unsigned long c, data; | |
142 | ||
1a3241ff | 143 | c = read_word_at_a_time(src+res); |
30035e45 CM |
144 | if (has_zero(c, &data, &constants)) { |
145 | data = prep_zero_mask(c, data, &constants); | |
146 | data = create_zero_mask(data); | |
990486c8 | 147 | *(unsigned long *)(dest+res) = c & zero_bytemask(data); |
30035e45 CM |
148 | return res + find_zero(data); |
149 | } | |
990486c8 | 150 | *(unsigned long *)(dest+res) = c; |
30035e45 CM |
151 | res += sizeof(unsigned long); |
152 | count -= sizeof(unsigned long); | |
153 | max -= sizeof(unsigned long); | |
154 | } | |
155 | ||
156 | while (count) { | |
157 | char c; | |
158 | ||
159 | c = src[res]; | |
160 | dest[res] = c; | |
161 | if (!c) | |
162 | return res; | |
163 | res++; | |
164 | count--; | |
165 | } | |
166 | ||
167 | /* Hit buffer length without finding a NUL; force NUL-termination. */ | |
168 | if (res) | |
169 | dest[res-1] = '\0'; | |
170 | ||
171 | return -E2BIG; | |
172 | } | |
e6584c39 | 173 | EXPORT_SYMBOL(sized_strscpy); |
30035e45 | 174 | |
1e1b6d63 ND |
175 | /** |
176 | * stpcpy - copy a string from src to dest returning a pointer to the new end | |
177 | * of dest, including src's %NUL-terminator. May overrun dest. | |
178 | * @dest: pointer to end of string being copied into. Must be large enough | |
179 | * to receive copy. | |
180 | * @src: pointer to the beginning of string being copied from. Must not overlap | |
181 | * dest. | |
182 | * | |
183 | * stpcpy differs from strcpy in a key way: the return value is a pointer | |
184 | * to the new %NUL-terminating character in @dest. (For strcpy, the return | |
185 | * value is a pointer to the start of @dest). This interface is considered | |
186 | * unsafe as it doesn't perform bounds checking of the inputs. As such it's | |
187 | * not recommended for usage. Instead, its definition is provided in case | |
188 | * the compiler lowers other libcalls to stpcpy. | |
189 | */ | |
190 | char *stpcpy(char *__restrict__ dest, const char *__restrict__ src); | |
191 | char *stpcpy(char *__restrict__ dest, const char *__restrict__ src) | |
192 | { | |
193 | while ((*dest++ = *src++) != '\0') | |
194 | /* nothing */; | |
195 | return --dest; | |
196 | } | |
197 | EXPORT_SYMBOL(stpcpy); | |
198 | ||
1da177e4 | 199 | #ifndef __HAVE_ARCH_STRCAT |
51a0f0f6 | 200 | char *strcat(char *dest, const char *src) |
1da177e4 LT |
201 | { |
202 | char *tmp = dest; | |
203 | ||
204 | while (*dest) | |
205 | dest++; | |
206 | while ((*dest++ = *src++) != '\0') | |
207 | ; | |
1da177e4 LT |
208 | return tmp; |
209 | } | |
210 | EXPORT_SYMBOL(strcat); | |
211 | #endif | |
212 | ||
213 | #ifndef __HAVE_ARCH_STRNCAT | |
51a0f0f6 | 214 | char *strncat(char *dest, const char *src, size_t count) |
1da177e4 LT |
215 | { |
216 | char *tmp = dest; | |
217 | ||
218 | if (count) { | |
219 | while (*dest) | |
220 | dest++; | |
221 | while ((*dest++ = *src++) != 0) { | |
222 | if (--count == 0) { | |
223 | *dest = '\0'; | |
224 | break; | |
225 | } | |
226 | } | |
227 | } | |
1da177e4 LT |
228 | return tmp; |
229 | } | |
230 | EXPORT_SYMBOL(strncat); | |
231 | #endif | |
232 | ||
233 | #ifndef __HAVE_ARCH_STRLCAT | |
1da177e4 LT |
234 | size_t strlcat(char *dest, const char *src, size_t count) |
235 | { | |
236 | size_t dsize = strlen(dest); | |
237 | size_t len = strlen(src); | |
238 | size_t res = dsize + len; | |
239 | ||
240 | /* This would be a bug */ | |
241 | BUG_ON(dsize >= count); | |
242 | ||
243 | dest += dsize; | |
244 | count -= dsize; | |
245 | if (len >= count) | |
246 | len = count-1; | |
f9cfb191 | 247 | __builtin_memcpy(dest, src, len); |
1da177e4 LT |
248 | dest[len] = 0; |
249 | return res; | |
250 | } | |
251 | EXPORT_SYMBOL(strlcat); | |
252 | #endif | |
253 | ||
254 | #ifndef __HAVE_ARCH_STRCMP | |
255 | /** | |
256 | * strcmp - Compare two strings | |
257 | * @cs: One string | |
258 | * @ct: Another string | |
259 | */ | |
51a0f0f6 | 260 | int strcmp(const char *cs, const char *ct) |
1da177e4 | 261 | { |
a414f01a | 262 | unsigned char c1, c2; |
1da177e4 LT |
263 | |
264 | while (1) { | |
a414f01a LT |
265 | c1 = *cs++; |
266 | c2 = *ct++; | |
267 | if (c1 != c2) | |
268 | return c1 < c2 ? -1 : 1; | |
269 | if (!c1) | |
1da177e4 LT |
270 | break; |
271 | } | |
a414f01a | 272 | return 0; |
1da177e4 LT |
273 | } |
274 | EXPORT_SYMBOL(strcmp); | |
275 | #endif | |
276 | ||
277 | #ifndef __HAVE_ARCH_STRNCMP | |
278 | /** | |
279 | * strncmp - Compare two length-limited strings | |
280 | * @cs: One string | |
281 | * @ct: Another string | |
282 | * @count: The maximum number of bytes to compare | |
283 | */ | |
51a0f0f6 | 284 | int strncmp(const char *cs, const char *ct, size_t count) |
1da177e4 | 285 | { |
a414f01a | 286 | unsigned char c1, c2; |
1da177e4 LT |
287 | |
288 | while (count) { | |
a414f01a LT |
289 | c1 = *cs++; |
290 | c2 = *ct++; | |
291 | if (c1 != c2) | |
292 | return c1 < c2 ? -1 : 1; | |
293 | if (!c1) | |
1da177e4 LT |
294 | break; |
295 | count--; | |
296 | } | |
a414f01a | 297 | return 0; |
1da177e4 LT |
298 | } |
299 | EXPORT_SYMBOL(strncmp); | |
300 | #endif | |
301 | ||
302 | #ifndef __HAVE_ARCH_STRCHR | |
303 | /** | |
304 | * strchr - Find the first occurrence of a character in a string | |
305 | * @s: The string to be searched | |
306 | * @c: The character to search for | |
b0975710 PR |
307 | * |
308 | * Note that the %NUL-terminator is considered part of the string, and can | |
309 | * be searched for. | |
1da177e4 | 310 | */ |
51a0f0f6 | 311 | char *strchr(const char *s, int c) |
1da177e4 | 312 | { |
51a0f0f6 | 313 | for (; *s != (char)c; ++s) |
1da177e4 LT |
314 | if (*s == '\0') |
315 | return NULL; | |
51a0f0f6 | 316 | return (char *)s; |
1da177e4 LT |
317 | } |
318 | EXPORT_SYMBOL(strchr); | |
319 | #endif | |
320 | ||
11d200e9 GL |
321 | #ifndef __HAVE_ARCH_STRCHRNUL |
322 | /** | |
323 | * strchrnul - Find and return a character in a string, or end of string | |
324 | * @s: The string to be searched | |
325 | * @c: The character to search for | |
326 | * | |
327 | * Returns pointer to first occurrence of 'c' in s. If c is not found, then | |
328 | * return a pointer to the null byte at the end of s. | |
329 | */ | |
330 | char *strchrnul(const char *s, int c) | |
331 | { | |
332 | while (*s && *s != (char)c) | |
333 | s++; | |
334 | return (char *)s; | |
335 | } | |
336 | EXPORT_SYMBOL(strchrnul); | |
337 | #endif | |
338 | ||
0bee0cec YN |
339 | /** |
340 | * strnchrnul - Find and return a character in a length limited string, | |
341 | * or end of string | |
342 | * @s: The string to be searched | |
343 | * @count: The number of characters to be searched | |
344 | * @c: The character to search for | |
345 | * | |
346 | * Returns pointer to the first occurrence of 'c' in s. If c is not found, | |
347 | * then return a pointer to the last character of the string. | |
348 | */ | |
349 | char *strnchrnul(const char *s, size_t count, int c) | |
350 | { | |
351 | while (count-- && *s && *s != (char)c) | |
352 | s++; | |
353 | return (char *)s; | |
354 | } | |
355 | ||
1da177e4 LT |
356 | #ifndef __HAVE_ARCH_STRRCHR |
357 | /** | |
358 | * strrchr - Find the last occurrence of a character in a string | |
359 | * @s: The string to be searched | |
360 | * @c: The character to search for | |
361 | */ | |
51a0f0f6 | 362 | char *strrchr(const char *s, int c) |
1da177e4 | 363 | { |
8da53d45 RV |
364 | const char *last = NULL; |
365 | do { | |
366 | if (*s == (char)c) | |
367 | last = s; | |
368 | } while (*s++); | |
369 | return (char *)last; | |
1da177e4 LT |
370 | } |
371 | EXPORT_SYMBOL(strrchr); | |
372 | #endif | |
373 | ||
374 | #ifndef __HAVE_ARCH_STRNCHR | |
375 | /** | |
376 | * strnchr - Find a character in a length limited string | |
377 | * @s: The string to be searched | |
378 | * @count: The number of characters to be searched | |
379 | * @c: The character to search for | |
b0975710 PR |
380 | * |
381 | * Note that the %NUL-terminator is considered part of the string, and can | |
382 | * be searched for. | |
1da177e4 LT |
383 | */ |
384 | char *strnchr(const char *s, size_t count, int c) | |
385 | { | |
b0975710 | 386 | while (count--) { |
51a0f0f6 JJ |
387 | if (*s == (char)c) |
388 | return (char *)s; | |
b0975710 PR |
389 | if (*s++ == '\0') |
390 | break; | |
391 | } | |
1da177e4 LT |
392 | return NULL; |
393 | } | |
394 | EXPORT_SYMBOL(strnchr); | |
395 | #endif | |
396 | ||
397 | #ifndef __HAVE_ARCH_STRLEN | |
51a0f0f6 | 398 | size_t strlen(const char *s) |
1da177e4 LT |
399 | { |
400 | const char *sc; | |
401 | ||
402 | for (sc = s; *sc != '\0'; ++sc) | |
403 | /* nothing */; | |
404 | return sc - s; | |
405 | } | |
406 | EXPORT_SYMBOL(strlen); | |
407 | #endif | |
408 | ||
409 | #ifndef __HAVE_ARCH_STRNLEN | |
51a0f0f6 | 410 | size_t strnlen(const char *s, size_t count) |
1da177e4 LT |
411 | { |
412 | const char *sc; | |
413 | ||
414 | for (sc = s; count-- && *sc != '\0'; ++sc) | |
415 | /* nothing */; | |
416 | return sc - s; | |
417 | } | |
418 | EXPORT_SYMBOL(strnlen); | |
419 | #endif | |
420 | ||
421 | #ifndef __HAVE_ARCH_STRSPN | |
422 | /** | |
72fd4a35 | 423 | * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept |
1da177e4 LT |
424 | * @s: The string to be searched |
425 | * @accept: The string to search for | |
426 | */ | |
427 | size_t strspn(const char *s, const char *accept) | |
428 | { | |
429 | const char *p; | |
1da177e4 LT |
430 | |
431 | for (p = s; *p != '\0'; ++p) { | |
dffad91b RV |
432 | if (!strchr(accept, *p)) |
433 | break; | |
1da177e4 | 434 | } |
dffad91b | 435 | return p - s; |
1da177e4 | 436 | } |
1da177e4 LT |
437 | EXPORT_SYMBOL(strspn); |
438 | #endif | |
439 | ||
8833d328 | 440 | #ifndef __HAVE_ARCH_STRCSPN |
1da177e4 | 441 | /** |
72fd4a35 | 442 | * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject |
1da177e4 LT |
443 | * @s: The string to be searched |
444 | * @reject: The string to avoid | |
445 | */ | |
446 | size_t strcspn(const char *s, const char *reject) | |
447 | { | |
448 | const char *p; | |
1da177e4 LT |
449 | |
450 | for (p = s; *p != '\0'; ++p) { | |
dffad91b RV |
451 | if (strchr(reject, *p)) |
452 | break; | |
1da177e4 | 453 | } |
dffad91b | 454 | return p - s; |
51a0f0f6 | 455 | } |
1da177e4 | 456 | EXPORT_SYMBOL(strcspn); |
8833d328 | 457 | #endif |
1da177e4 LT |
458 | |
459 | #ifndef __HAVE_ARCH_STRPBRK | |
460 | /** | |
461 | * strpbrk - Find the first occurrence of a set of characters | |
462 | * @cs: The string to be searched | |
463 | * @ct: The characters to search for | |
464 | */ | |
51a0f0f6 | 465 | char *strpbrk(const char *cs, const char *ct) |
1da177e4 | 466 | { |
a8c55407 | 467 | const char *sc; |
1da177e4 | 468 | |
a8c55407 AS |
469 | for (sc = cs; *sc != '\0'; ++sc) { |
470 | if (strchr(ct, *sc)) | |
471 | return (char *)sc; | |
1da177e4 LT |
472 | } |
473 | return NULL; | |
474 | } | |
894b5779 | 475 | EXPORT_SYMBOL(strpbrk); |
1da177e4 LT |
476 | #endif |
477 | ||
478 | #ifndef __HAVE_ARCH_STRSEP | |
479 | /** | |
480 | * strsep - Split a string into tokens | |
481 | * @s: The string to be searched | |
482 | * @ct: The characters to search for | |
483 | * | |
484 | * strsep() updates @s to point after the token, ready for the next call. | |
485 | * | |
486 | * It returns empty tokens, too, behaving exactly like the libc function | |
487 | * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. | |
488 | * Same semantics, slimmer shape. ;) | |
489 | */ | |
51a0f0f6 | 490 | char *strsep(char **s, const char *ct) |
1da177e4 | 491 | { |
51a0f0f6 JJ |
492 | char *sbegin = *s; |
493 | char *end; | |
1da177e4 LT |
494 | |
495 | if (sbegin == NULL) | |
496 | return NULL; | |
497 | ||
498 | end = strpbrk(sbegin, ct); | |
499 | if (end) | |
500 | *end++ = '\0'; | |
501 | *s = end; | |
1da177e4 LT |
502 | return sbegin; |
503 | } | |
1da177e4 LT |
504 | EXPORT_SYMBOL(strsep); |
505 | #endif | |
506 | ||
507 | #ifndef __HAVE_ARCH_MEMSET | |
508 | /** | |
509 | * memset - Fill a region of memory with the given value | |
510 | * @s: Pointer to the start of the area. | |
511 | * @c: The byte to fill the area with | |
512 | * @count: The size of the area. | |
513 | * | |
514 | * Do not use memset() to access IO space, use memset_io() instead. | |
515 | */ | |
51a0f0f6 | 516 | void *memset(void *s, int c, size_t count) |
1da177e4 | 517 | { |
850b9247 | 518 | char *xs = s; |
1da177e4 LT |
519 | |
520 | while (count--) | |
521 | *xs++ = c; | |
1da177e4 LT |
522 | return s; |
523 | } | |
524 | EXPORT_SYMBOL(memset); | |
525 | #endif | |
526 | ||
3b3c4bab MW |
527 | #ifndef __HAVE_ARCH_MEMSET16 |
528 | /** | |
529 | * memset16() - Fill a memory area with a uint16_t | |
530 | * @s: Pointer to the start of the area. | |
531 | * @v: The value to fill the area with | |
532 | * @count: The number of values to store | |
533 | * | |
534 | * Differs from memset() in that it fills with a uint16_t instead | |
535 | * of a byte. Remember that @count is the number of uint16_ts to | |
536 | * store, not the number of bytes. | |
537 | */ | |
538 | void *memset16(uint16_t *s, uint16_t v, size_t count) | |
539 | { | |
540 | uint16_t *xs = s; | |
541 | ||
542 | while (count--) | |
543 | *xs++ = v; | |
544 | return s; | |
545 | } | |
546 | EXPORT_SYMBOL(memset16); | |
547 | #endif | |
548 | ||
549 | #ifndef __HAVE_ARCH_MEMSET32 | |
550 | /** | |
551 | * memset32() - Fill a memory area with a uint32_t | |
552 | * @s: Pointer to the start of the area. | |
553 | * @v: The value to fill the area with | |
554 | * @count: The number of values to store | |
555 | * | |
556 | * Differs from memset() in that it fills with a uint32_t instead | |
557 | * of a byte. Remember that @count is the number of uint32_ts to | |
558 | * store, not the number of bytes. | |
559 | */ | |
560 | void *memset32(uint32_t *s, uint32_t v, size_t count) | |
561 | { | |
562 | uint32_t *xs = s; | |
563 | ||
564 | while (count--) | |
565 | *xs++ = v; | |
566 | return s; | |
567 | } | |
568 | EXPORT_SYMBOL(memset32); | |
569 | #endif | |
570 | ||
571 | #ifndef __HAVE_ARCH_MEMSET64 | |
572 | /** | |
573 | * memset64() - Fill a memory area with a uint64_t | |
574 | * @s: Pointer to the start of the area. | |
575 | * @v: The value to fill the area with | |
576 | * @count: The number of values to store | |
577 | * | |
578 | * Differs from memset() in that it fills with a uint64_t instead | |
579 | * of a byte. Remember that @count is the number of uint64_ts to | |
580 | * store, not the number of bytes. | |
581 | */ | |
582 | void *memset64(uint64_t *s, uint64_t v, size_t count) | |
583 | { | |
584 | uint64_t *xs = s; | |
585 | ||
586 | while (count--) | |
587 | *xs++ = v; | |
588 | return s; | |
589 | } | |
590 | EXPORT_SYMBOL(memset64); | |
591 | #endif | |
592 | ||
1da177e4 LT |
593 | #ifndef __HAVE_ARCH_MEMCPY |
594 | /** | |
595 | * memcpy - Copy one area of memory to another | |
596 | * @dest: Where to copy to | |
597 | * @src: Where to copy from | |
598 | * @count: The size of the area. | |
599 | * | |
600 | * You should not use this function to access IO space, use memcpy_toio() | |
601 | * or memcpy_fromio() instead. | |
602 | */ | |
51a0f0f6 | 603 | void *memcpy(void *dest, const void *src, size_t count) |
1da177e4 | 604 | { |
850b9247 | 605 | char *tmp = dest; |
4c416ab7 | 606 | const char *s = src; |
1da177e4 LT |
607 | |
608 | while (count--) | |
609 | *tmp++ = *s++; | |
1da177e4 LT |
610 | return dest; |
611 | } | |
612 | EXPORT_SYMBOL(memcpy); | |
613 | #endif | |
614 | ||
615 | #ifndef __HAVE_ARCH_MEMMOVE | |
616 | /** | |
617 | * memmove - Copy one area of memory to another | |
618 | * @dest: Where to copy to | |
619 | * @src: Where to copy from | |
620 | * @count: The size of the area. | |
621 | * | |
622 | * Unlike memcpy(), memmove() copes with overlapping areas. | |
623 | */ | |
51a0f0f6 | 624 | void *memmove(void *dest, const void *src, size_t count) |
1da177e4 | 625 | { |
82da2c37 PJ |
626 | char *tmp; |
627 | const char *s; | |
1da177e4 LT |
628 | |
629 | if (dest <= src) { | |
850b9247 JJ |
630 | tmp = dest; |
631 | s = src; | |
1da177e4 LT |
632 | while (count--) |
633 | *tmp++ = *s++; | |
51a0f0f6 | 634 | } else { |
850b9247 JJ |
635 | tmp = dest; |
636 | tmp += count; | |
637 | s = src; | |
638 | s += count; | |
1da177e4 LT |
639 | while (count--) |
640 | *--tmp = *--s; | |
51a0f0f6 | 641 | } |
1da177e4 LT |
642 | return dest; |
643 | } | |
644 | EXPORT_SYMBOL(memmove); | |
645 | #endif | |
646 | ||
647 | #ifndef __HAVE_ARCH_MEMCMP | |
648 | /** | |
649 | * memcmp - Compare two areas of memory | |
650 | * @cs: One area of memory | |
651 | * @ct: Another area of memory | |
652 | * @count: The size of the area. | |
653 | */ | |
0c28130b | 654 | #undef memcmp |
a7330c99 | 655 | __visible int memcmp(const void *cs, const void *ct, size_t count) |
1da177e4 LT |
656 | { |
657 | const unsigned char *su1, *su2; | |
658 | int res = 0; | |
659 | ||
291d47cc LT |
660 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS |
661 | if (count >= sizeof(unsigned long)) { | |
662 | const unsigned long *u1 = cs; | |
663 | const unsigned long *u2 = ct; | |
664 | do { | |
665 | if (get_unaligned(u1) != get_unaligned(u2)) | |
666 | break; | |
667 | u1++; | |
668 | u2++; | |
669 | count -= sizeof(unsigned long); | |
670 | } while (count >= sizeof(unsigned long)); | |
671 | cs = u1; | |
672 | ct = u2; | |
673 | } | |
674 | #endif | |
51a0f0f6 | 675 | for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) |
1da177e4 LT |
676 | if ((res = *su1 - *su2) != 0) |
677 | break; | |
678 | return res; | |
679 | } | |
680 | EXPORT_SYMBOL(memcmp); | |
681 | #endif | |
682 | ||
5f074f3e ND |
683 | #ifndef __HAVE_ARCH_BCMP |
684 | /** | |
685 | * bcmp - returns 0 if and only if the buffers have identical contents. | |
686 | * @a: pointer to first buffer. | |
687 | * @b: pointer to second buffer. | |
688 | * @len: size of buffers. | |
689 | * | |
690 | * The sign or magnitude of a non-zero return value has no particular | |
691 | * meaning, and architectures may implement their own more efficient bcmp(). So | |
692 | * while this particular implementation is a simple (tail) call to memcmp, do | |
693 | * not rely on anything but whether the return value is zero or non-zero. | |
694 | */ | |
5f074f3e ND |
695 | int bcmp(const void *a, const void *b, size_t len) |
696 | { | |
697 | return memcmp(a, b, len); | |
698 | } | |
699 | EXPORT_SYMBOL(bcmp); | |
700 | #endif | |
701 | ||
1da177e4 LT |
702 | #ifndef __HAVE_ARCH_MEMSCAN |
703 | /** | |
704 | * memscan - Find a character in an area of memory. | |
705 | * @addr: The memory area | |
706 | * @c: The byte to search for | |
707 | * @size: The size of the area. | |
708 | * | |
709 | * returns the address of the first occurrence of @c, or 1 byte past | |
710 | * the area if @c is not found | |
711 | */ | |
51a0f0f6 | 712 | void *memscan(void *addr, int c, size_t size) |
1da177e4 | 713 | { |
850b9247 | 714 | unsigned char *p = addr; |
1da177e4 LT |
715 | |
716 | while (size) { | |
1a58be62 | 717 | if (*p == (unsigned char)c) |
51a0f0f6 | 718 | return (void *)p; |
1da177e4 LT |
719 | p++; |
720 | size--; | |
721 | } | |
51a0f0f6 | 722 | return (void *)p; |
1da177e4 LT |
723 | } |
724 | EXPORT_SYMBOL(memscan); | |
725 | #endif | |
726 | ||
727 | #ifndef __HAVE_ARCH_STRSTR | |
728 | /** | |
729 | * strstr - Find the first substring in a %NUL terminated string | |
730 | * @s1: The string to be searched | |
731 | * @s2: The string to search for | |
732 | */ | |
51a0f0f6 | 733 | char *strstr(const char *s1, const char *s2) |
1da177e4 | 734 | { |
d5f1fb53 | 735 | size_t l1, l2; |
1da177e4 LT |
736 | |
737 | l2 = strlen(s2); | |
738 | if (!l2) | |
51a0f0f6 | 739 | return (char *)s1; |
1da177e4 LT |
740 | l1 = strlen(s1); |
741 | while (l1 >= l2) { | |
742 | l1--; | |
51a0f0f6 JJ |
743 | if (!memcmp(s1, s2, l2)) |
744 | return (char *)s1; | |
1da177e4 LT |
745 | s1++; |
746 | } | |
747 | return NULL; | |
748 | } | |
749 | EXPORT_SYMBOL(strstr); | |
750 | #endif | |
751 | ||
d5f1fb53 LZ |
752 | #ifndef __HAVE_ARCH_STRNSTR |
753 | /** | |
754 | * strnstr - Find the first substring in a length-limited string | |
755 | * @s1: The string to be searched | |
756 | * @s2: The string to search for | |
757 | * @len: the maximum number of characters to search | |
758 | */ | |
759 | char *strnstr(const char *s1, const char *s2, size_t len) | |
760 | { | |
d6a2eedf | 761 | size_t l2; |
d5f1fb53 LZ |
762 | |
763 | l2 = strlen(s2); | |
764 | if (!l2) | |
765 | return (char *)s1; | |
d6a2eedf AGR |
766 | while (len >= l2) { |
767 | len--; | |
d5f1fb53 LZ |
768 | if (!memcmp(s1, s2, l2)) |
769 | return (char *)s1; | |
770 | s1++; | |
771 | } | |
772 | return NULL; | |
773 | } | |
774 | EXPORT_SYMBOL(strnstr); | |
775 | #endif | |
776 | ||
1da177e4 LT |
777 | #ifndef __HAVE_ARCH_MEMCHR |
778 | /** | |
779 | * memchr - Find a character in an area of memory. | |
780 | * @s: The memory area | |
781 | * @c: The byte to search for | |
782 | * @n: The size of the area. | |
783 | * | |
784 | * returns the address of the first occurrence of @c, or %NULL | |
785 | * if @c is not found | |
786 | */ | |
787 | void *memchr(const void *s, int c, size_t n) | |
788 | { | |
789 | const unsigned char *p = s; | |
790 | while (n-- != 0) { | |
791 | if ((unsigned char)c == *p++) { | |
51a0f0f6 | 792 | return (void *)(p - 1); |
1da177e4 LT |
793 | } |
794 | } | |
795 | return NULL; | |
796 | } | |
797 | EXPORT_SYMBOL(memchr); | |
798 | #endif | |
79824820 AM |
799 | |
800 | static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) | |
801 | { | |
802 | while (bytes) { | |
803 | if (*start != value) | |
804 | return (void *)start; | |
805 | start++; | |
806 | bytes--; | |
807 | } | |
808 | return NULL; | |
809 | } | |
810 | ||
811 | /** | |
812 | * memchr_inv - Find an unmatching character in an area of memory. | |
813 | * @start: The memory area | |
814 | * @c: Find a character other than c | |
815 | * @bytes: The size of the area. | |
816 | * | |
817 | * returns the address of the first character other than @c, or %NULL | |
818 | * if the whole buffer contains just @c. | |
819 | */ | |
820 | void *memchr_inv(const void *start, int c, size_t bytes) | |
821 | { | |
822 | u8 value = c; | |
823 | u64 value64; | |
824 | unsigned int words, prefix; | |
825 | ||
826 | if (bytes <= 16) | |
827 | return check_bytes8(start, value, bytes); | |
828 | ||
f43804bf | 829 | value64 = value; |
72d93104 | 830 | #if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 |
3368e8fb | 831 | value64 *= 0x0101010101010101ULL; |
72d93104 | 832 | #elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) |
f43804bf AM |
833 | value64 *= 0x01010101; |
834 | value64 |= value64 << 32; | |
835 | #else | |
836 | value64 |= value64 << 8; | |
837 | value64 |= value64 << 16; | |
838 | value64 |= value64 << 32; | |
839 | #endif | |
79824820 | 840 | |
f43804bf | 841 | prefix = (unsigned long)start % 8; |
79824820 | 842 | if (prefix) { |
f43804bf AM |
843 | u8 *r; |
844 | ||
845 | prefix = 8 - prefix; | |
846 | r = check_bytes8(start, value, prefix); | |
79824820 AM |
847 | if (r) |
848 | return r; | |
849 | start += prefix; | |
850 | bytes -= prefix; | |
851 | } | |
852 | ||
853 | words = bytes / 8; | |
854 | ||
855 | while (words) { | |
856 | if (*(u64 *)start != value64) | |
857 | return check_bytes8(start, value, 8); | |
858 | start += 8; | |
859 | words--; | |
860 | } | |
861 | ||
862 | return check_bytes8(start, value, bytes % 8); | |
863 | } | |
864 | EXPORT_SYMBOL(memchr_inv); |