blob: 8f1a2a04e22f50cd9239689780ef34a9856b9f50 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/lib/string.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7/*
8 * stupid library routines.. The optimized versions should generally be found
9 * as inline code in <asm-xx/string.h>
10 *
11 * These are buggy as well..
12 *
13 * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de>
14 * - Added strsep() which will replace strtok() soon (because strsep() is
15 * reentrant and should be faster). Use only strsep() in new code, please.
16 *
17 * * Sat Feb 09 2002, Jason Thomas <jason@topic.com.au>,
18 * Matthew Hawkins <matt@mh.dropbear.id.au>
19 * - Kissed strtok() goodbye
20 */
21
22#include <linux/types.h>
23#include <linux/string.h>
24#include <linux/ctype.h>
Paul Gortmaker8bc3bcc2011-11-16 21:29:17 -050025#include <linux/kernel.h>
26#include <linux/export.h>
Paul Gortmaker50af5ea2012-01-20 18:35:53 -050027#include <linux/bug.h>
Paul Gortmaker8bc3bcc2011-11-16 21:29:17 -050028#include <linux/errno.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
Chris Metcalf30035e42015-04-29 12:52:04 -040030#include <asm/byteorder.h>
31#include <asm/word-at-a-time.h>
32#include <asm/page.h>
33
Rasmus Villemoescd514e72014-10-13 15:54:25 -070034#ifndef __HAVE_ARCH_STRNCASECMP
Linus Torvalds1da177e2005-04-16 15:20:36 -070035/**
Rasmus Villemoescd514e72014-10-13 15:54:25 -070036 * strncasecmp - Case insensitive, length-limited string comparison
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 * @s1: One string
38 * @s2: The other string
39 * @len: the maximum number of characters to compare
40 */
Rasmus Villemoescd514e72014-10-13 15:54:25 -070041int strncasecmp(const char *s1, const char *s2, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -070042{
43 /* Yes, Virginia, it had better be unsigned */
44 unsigned char c1, c2;
45
André Goddard Rosaa11d2b62010-03-05 13:43:11 -080046 if (!len)
47 return 0;
48
49 do {
50 c1 = *s1++;
51 c2 = *s2++;
52 if (!c1 || !c2)
53 break;
54 if (c1 == c2)
55 continue;
56 c1 = tolower(c1);
57 c2 = tolower(c2);
58 if (c1 != c2)
59 break;
60 } while (--len);
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 return (int)c1 - (int)c2;
62}
Rasmus Villemoescd514e72014-10-13 15:54:25 -070063EXPORT_SYMBOL(strncasecmp);
64#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
David S. Millerded220b2007-03-29 01:18:42 -070066#ifndef __HAVE_ARCH_STRCASECMP
67int strcasecmp(const char *s1, const char *s2)
68{
69 int c1, c2;
70
71 do {
72 c1 = tolower(*s1++);
73 c2 = tolower(*s2++);
74 } while (c1 == c2 && c1 != 0);
75 return c1 - c2;
76}
77EXPORT_SYMBOL(strcasecmp);
78#endif
79
Linus Torvalds1da177e2005-04-16 15:20:36 -070080#ifndef __HAVE_ARCH_STRCPY
81/**
82 * strcpy - Copy a %NUL terminated string
83 * @dest: Where to copy the string to
84 * @src: Where to copy the string from
85 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -070086#undef strcpy
Jesper Juhl51a0f0f2005-10-30 15:02:11 -080087char *strcpy(char *dest, const char *src)
Linus Torvalds1da177e2005-04-16 15:20:36 -070088{
89 char *tmp = dest;
90
91 while ((*dest++ = *src++) != '\0')
92 /* nothing */;
93 return tmp;
94}
95EXPORT_SYMBOL(strcpy);
96#endif
97
98#ifndef __HAVE_ARCH_STRNCPY
99/**
Dan Carpenter0046dd92014-06-04 16:11:47 -0700100 * strncpy - Copy a length-limited, C-string
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 * @dest: Where to copy the string to
102 * @src: Where to copy the string from
103 * @count: The maximum number of bytes to copy
104 *
105 * The result is not %NUL-terminated if the source exceeds
106 * @count bytes.
walter harms25279522005-05-05 16:16:20 -0700107 *
108 * In the case where the length of @src is less than that of
109 * count, the remainder of @dest will be padded with %NUL.
110 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800112char *strncpy(char *dest, const char *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113{
114 char *tmp = dest;
115
116 while (count) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800117 if ((*tmp = *src) != 0)
118 src++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 tmp++;
120 count--;
121 }
122 return dest;
123}
124EXPORT_SYMBOL(strncpy);
125#endif
126
127#ifndef __HAVE_ARCH_STRLCPY
128/**
Dan Carpenter0046dd92014-06-04 16:11:47 -0700129 * strlcpy - Copy a C-string into a sized buffer
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 * @dest: Where to copy the string to
131 * @src: Where to copy the string from
132 * @size: size of destination buffer
133 *
134 * Compatible with *BSD: the result is always a valid
135 * NUL-terminated string that fits in the buffer (unless,
136 * of course, the buffer size is zero). It does not pad
137 * out the result like strncpy() does.
138 */
139size_t strlcpy(char *dest, const char *src, size_t size)
140{
141 size_t ret = strlen(src);
142
143 if (size) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800144 size_t len = (ret >= size) ? size - 1 : ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 memcpy(dest, src, len);
146 dest[len] = '\0';
147 }
148 return ret;
149}
150EXPORT_SYMBOL(strlcpy);
151#endif
152
Chris Metcalf30035e42015-04-29 12:52:04 -0400153#ifndef __HAVE_ARCH_STRSCPY
154/**
155 * strscpy - Copy a C-string into a sized buffer
156 * @dest: Where to copy the string to
157 * @src: Where to copy the string from
158 * @count: Size of destination buffer
159 *
160 * Copy the string, or as much of it as fits, into the dest buffer.
161 * The routine returns the number of characters copied (not including
162 * the trailing NUL) or -E2BIG if the destination buffer wasn't big enough.
163 * The behavior is undefined if the string buffers overlap.
164 * The destination buffer is always NUL terminated, unless it's zero-sized.
165 *
166 * Preferred to strlcpy() since the API doesn't require reading memory
167 * from the src string beyond the specified "count" bytes, and since
168 * the return value is easier to error-check than strlcpy()'s.
169 * In addition, the implementation is robust to the string changing out
170 * from underneath it, unlike the current strlcpy() implementation.
171 *
172 * Preferred to strncpy() since it always returns a valid string, and
173 * doesn't unnecessarily force the tail of the destination buffer to be
174 * zeroed. If the zeroing is desired, it's likely cleaner to use strscpy()
175 * with an overflow test, then just memset() the tail of the dest buffer.
176 */
177ssize_t strscpy(char *dest, const char *src, size_t count)
178{
179 const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
180 size_t max = count;
181 long res = 0;
182
183 if (count == 0)
184 return -E2BIG;
185
186#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
187 /*
188 * If src is unaligned, don't cross a page boundary,
189 * since we don't know if the next page is mapped.
190 */
191 if ((long)src & (sizeof(long) - 1)) {
192 size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1));
193 if (limit < max)
194 max = limit;
195 }
196#else
197 /* If src or dest is unaligned, don't do word-at-a-time. */
198 if (((long) dest | (long) src) & (sizeof(long) - 1))
199 max = 0;
200#endif
201
202 while (max >= sizeof(unsigned long)) {
203 unsigned long c, data;
204
Andrey Ryabinin8dd8b4d2018-02-01 21:00:50 +0300205 c = read_word_at_a_time(src+res);
Chris Metcalf30035e42015-04-29 12:52:04 -0400206 if (has_zero(c, &data, &constants)) {
207 data = prep_zero_mask(c, data, &constants);
208 data = create_zero_mask(data);
Chris Metcalf990486c2015-10-06 12:37:41 -0400209 *(unsigned long *)(dest+res) = c & zero_bytemask(data);
Chris Metcalf30035e42015-04-29 12:52:04 -0400210 return res + find_zero(data);
211 }
Chris Metcalf990486c2015-10-06 12:37:41 -0400212 *(unsigned long *)(dest+res) = c;
Chris Metcalf30035e42015-04-29 12:52:04 -0400213 res += sizeof(unsigned long);
214 count -= sizeof(unsigned long);
215 max -= sizeof(unsigned long);
216 }
217
218 while (count) {
219 char c;
220
221 c = src[res];
222 dest[res] = c;
223 if (!c)
224 return res;
225 res++;
226 count--;
227 }
228
229 /* Hit buffer length without finding a NUL; force NUL-termination. */
230 if (res)
231 dest[res-1] = '\0';
232
233 return -E2BIG;
234}
235EXPORT_SYMBOL(strscpy);
236#endif
237
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238#ifndef __HAVE_ARCH_STRCAT
239/**
240 * strcat - Append one %NUL-terminated string to another
241 * @dest: The string to be appended to
242 * @src: The string to append to it
243 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700244#undef strcat
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800245char *strcat(char *dest, const char *src)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246{
247 char *tmp = dest;
248
249 while (*dest)
250 dest++;
251 while ((*dest++ = *src++) != '\0')
252 ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 return tmp;
254}
255EXPORT_SYMBOL(strcat);
256#endif
257
258#ifndef __HAVE_ARCH_STRNCAT
259/**
Dan Carpenter0046dd92014-06-04 16:11:47 -0700260 * strncat - Append a length-limited, C-string to another
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 * @dest: The string to be appended to
262 * @src: The string to append to it
263 * @count: The maximum numbers of bytes to copy
264 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800265 * Note that in contrast to strncpy(), strncat() ensures the result is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 * terminated.
267 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800268char *strncat(char *dest, const char *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269{
270 char *tmp = dest;
271
272 if (count) {
273 while (*dest)
274 dest++;
275 while ((*dest++ = *src++) != 0) {
276 if (--count == 0) {
277 *dest = '\0';
278 break;
279 }
280 }
281 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 return tmp;
283}
284EXPORT_SYMBOL(strncat);
285#endif
286
287#ifndef __HAVE_ARCH_STRLCAT
288/**
Dan Carpenter0046dd92014-06-04 16:11:47 -0700289 * strlcat - Append a length-limited, C-string to another
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 * @dest: The string to be appended to
291 * @src: The string to append to it
292 * @count: The size of the destination buffer.
293 */
294size_t strlcat(char *dest, const char *src, size_t count)
295{
296 size_t dsize = strlen(dest);
297 size_t len = strlen(src);
298 size_t res = dsize + len;
299
300 /* This would be a bug */
301 BUG_ON(dsize >= count);
302
303 dest += dsize;
304 count -= dsize;
305 if (len >= count)
306 len = count-1;
307 memcpy(dest, src, len);
308 dest[len] = 0;
309 return res;
310}
311EXPORT_SYMBOL(strlcat);
312#endif
313
314#ifndef __HAVE_ARCH_STRCMP
315/**
316 * strcmp - Compare two strings
317 * @cs: One string
318 * @ct: Another string
319 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700320#undef strcmp
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800321int strcmp(const char *cs, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322{
Linus Torvaldsa414f012009-11-18 22:31:52 +0100323 unsigned char c1, c2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
325 while (1) {
Linus Torvaldsa414f012009-11-18 22:31:52 +0100326 c1 = *cs++;
327 c2 = *ct++;
328 if (c1 != c2)
329 return c1 < c2 ? -1 : 1;
330 if (!c1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 break;
332 }
Linus Torvaldsa414f012009-11-18 22:31:52 +0100333 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334}
335EXPORT_SYMBOL(strcmp);
336#endif
337
338#ifndef __HAVE_ARCH_STRNCMP
339/**
340 * strncmp - Compare two length-limited strings
341 * @cs: One string
342 * @ct: Another string
343 * @count: The maximum number of bytes to compare
344 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800345int strncmp(const char *cs, const char *ct, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346{
Linus Torvaldsa414f012009-11-18 22:31:52 +0100347 unsigned char c1, c2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348
349 while (count) {
Linus Torvaldsa414f012009-11-18 22:31:52 +0100350 c1 = *cs++;
351 c2 = *ct++;
352 if (c1 != c2)
353 return c1 < c2 ? -1 : 1;
354 if (!c1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 break;
356 count--;
357 }
Linus Torvaldsa414f012009-11-18 22:31:52 +0100358 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359}
360EXPORT_SYMBOL(strncmp);
361#endif
362
363#ifndef __HAVE_ARCH_STRCHR
364/**
365 * strchr - Find the first occurrence of a character in a string
366 * @s: The string to be searched
367 * @c: The character to search for
368 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800369char *strchr(const char *s, int c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800371 for (; *s != (char)c; ++s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 if (*s == '\0')
373 return NULL;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800374 return (char *)s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375}
376EXPORT_SYMBOL(strchr);
377#endif
378
Grant Likely11d200e2014-03-14 17:00:14 +0000379#ifndef __HAVE_ARCH_STRCHRNUL
380/**
381 * strchrnul - Find and return a character in a string, or end of string
382 * @s: The string to be searched
383 * @c: The character to search for
384 *
385 * Returns pointer to first occurrence of 'c' in s. If c is not found, then
386 * return a pointer to the null byte at the end of s.
387 */
388char *strchrnul(const char *s, int c)
389{
390 while (*s && *s != (char)c)
391 s++;
392 return (char *)s;
393}
394EXPORT_SYMBOL(strchrnul);
395#endif
396
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397#ifndef __HAVE_ARCH_STRRCHR
398/**
399 * strrchr - Find the last occurrence of a character in a string
400 * @s: The string to be searched
401 * @c: The character to search for
402 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800403char *strrchr(const char *s, int c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404{
Rasmus Villemoes8da53d42015-02-13 14:36:44 -0800405 const char *last = NULL;
406 do {
407 if (*s == (char)c)
408 last = s;
409 } while (*s++);
410 return (char *)last;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411}
412EXPORT_SYMBOL(strrchr);
413#endif
414
415#ifndef __HAVE_ARCH_STRNCHR
416/**
417 * strnchr - Find a character in a length limited string
418 * @s: The string to be searched
419 * @count: The number of characters to be searched
420 * @c: The character to search for
421 */
422char *strnchr(const char *s, size_t count, int c)
423{
424 for (; count-- && *s != '\0'; ++s)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800425 if (*s == (char)c)
426 return (char *)s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 return NULL;
428}
429EXPORT_SYMBOL(strnchr);
430#endif
431
Pekka Enberg481fad42006-06-23 02:05:44 -0700432/**
Randy Dunlapa6cd13f2009-12-21 14:37:22 -0800433 * skip_spaces - Removes leading whitespace from @str.
434 * @str: The string to be stripped.
André Goddard Rosaf6533982009-12-14 18:01:04 -0800435 *
Randy Dunlapa6cd13f2009-12-21 14:37:22 -0800436 * Returns a pointer to the first non-whitespace character in @str.
André Goddard Rosaf6533982009-12-14 18:01:04 -0800437 */
438char *skip_spaces(const char *str)
439{
440 while (isspace(*str))
441 ++str;
442 return (char *)str;
443}
444EXPORT_SYMBOL(skip_spaces);
445
446/**
KOSAKI Motohiroca54cb82009-12-14 18:01:15 -0800447 * strim - Removes leading and trailing whitespace from @s.
Pekka Enberg481fad42006-06-23 02:05:44 -0700448 * @s: The string to be stripped.
449 *
450 * Note that the first trailing whitespace is replaced with a %NUL-terminator
451 * in the given string @s. Returns a pointer to the first non-whitespace
452 * character in @s.
453 */
KOSAKI Motohiroca54cb82009-12-14 18:01:15 -0800454char *strim(char *s)
Pekka Enberg481fad42006-06-23 02:05:44 -0700455{
456 size_t size;
457 char *end;
458
459 size = strlen(s);
Pekka Enberg481fad42006-06-23 02:05:44 -0700460 if (!size)
461 return s;
462
463 end = s + size - 1;
Michael Holzheu6e6d9fa2006-10-28 10:38:47 -0700464 while (end >= s && isspace(*end))
Pekka Enberg481fad42006-06-23 02:05:44 -0700465 end--;
466 *(end + 1) = '\0';
467
Michael Holzheu66f69582011-10-31 17:12:37 -0700468 return skip_spaces(s);
Pekka Enberg481fad42006-06-23 02:05:44 -0700469}
KOSAKI Motohiroca54cb82009-12-14 18:01:15 -0800470EXPORT_SYMBOL(strim);
Pekka Enberg481fad42006-06-23 02:05:44 -0700471
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472#ifndef __HAVE_ARCH_STRLEN
473/**
474 * strlen - Find the length of a string
475 * @s: The string to be sized
476 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800477size_t strlen(const char *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478{
479 const char *sc;
480
481 for (sc = s; *sc != '\0'; ++sc)
482 /* nothing */;
483 return sc - s;
484}
485EXPORT_SYMBOL(strlen);
486#endif
487
488#ifndef __HAVE_ARCH_STRNLEN
489/**
490 * strnlen - Find the length of a length-limited string
491 * @s: The string to be sized
492 * @count: The maximum number of bytes to search
493 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800494size_t strnlen(const char *s, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495{
496 const char *sc;
497
498 for (sc = s; count-- && *sc != '\0'; ++sc)
499 /* nothing */;
500 return sc - s;
501}
502EXPORT_SYMBOL(strnlen);
503#endif
504
505#ifndef __HAVE_ARCH_STRSPN
506/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800507 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 * @s: The string to be searched
509 * @accept: The string to search for
510 */
511size_t strspn(const char *s, const char *accept)
512{
513 const char *p;
514 const char *a;
515 size_t count = 0;
516
517 for (p = s; *p != '\0'; ++p) {
518 for (a = accept; *a != '\0'; ++a) {
519 if (*p == *a)
520 break;
521 }
522 if (*a == '\0')
523 return count;
524 ++count;
525 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 return count;
527}
528
529EXPORT_SYMBOL(strspn);
530#endif
531
Kyle McMartin8833d322006-04-10 22:53:57 -0700532#ifndef __HAVE_ARCH_STRCSPN
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800534 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 * @s: The string to be searched
536 * @reject: The string to avoid
537 */
538size_t strcspn(const char *s, const char *reject)
539{
540 const char *p;
541 const char *r;
542 size_t count = 0;
543
544 for (p = s; *p != '\0'; ++p) {
545 for (r = reject; *r != '\0'; ++r) {
546 if (*p == *r)
547 return count;
548 }
549 ++count;
550 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 return count;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800552}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553EXPORT_SYMBOL(strcspn);
Kyle McMartin8833d322006-04-10 22:53:57 -0700554#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555
556#ifndef __HAVE_ARCH_STRPBRK
557/**
558 * strpbrk - Find the first occurrence of a set of characters
559 * @cs: The string to be searched
560 * @ct: The characters to search for
561 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800562char *strpbrk(const char *cs, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800564 const char *sc1, *sc2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800566 for (sc1 = cs; *sc1 != '\0'; ++sc1) {
567 for (sc2 = ct; *sc2 != '\0'; ++sc2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 if (*sc1 == *sc2)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800569 return (char *)sc1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 }
571 }
572 return NULL;
573}
Kyle McMartin894b5772006-04-10 22:53:56 -0700574EXPORT_SYMBOL(strpbrk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575#endif
576
577#ifndef __HAVE_ARCH_STRSEP
578/**
579 * strsep - Split a string into tokens
580 * @s: The string to be searched
581 * @ct: The characters to search for
582 *
583 * strsep() updates @s to point after the token, ready for the next call.
584 *
585 * It returns empty tokens, too, behaving exactly like the libc function
586 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
587 * Same semantics, slimmer shape. ;)
588 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800589char *strsep(char **s, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800591 char *sbegin = *s;
592 char *end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
594 if (sbegin == NULL)
595 return NULL;
596
597 end = strpbrk(sbegin, ct);
598 if (end)
599 *end++ = '\0';
600 *s = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 return sbegin;
602}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603EXPORT_SYMBOL(strsep);
604#endif
605
David Brownell34990cf2008-05-01 04:34:42 -0700606/**
607 * sysfs_streq - return true if strings are equal, modulo trailing newline
608 * @s1: one string
609 * @s2: another string
610 *
611 * This routine returns true iff two strings are equal, treating both
612 * NUL and newline-then-NUL as equivalent string terminations. It's
613 * geared for use with sysfs input strings, which generally terminate
614 * with newlines but are compared against values without newlines.
615 */
616bool sysfs_streq(const char *s1, const char *s2)
617{
618 while (*s1 && *s1 == *s2) {
619 s1++;
620 s2++;
621 }
622
623 if (*s1 == *s2)
624 return true;
625 if (!*s1 && *s2 == '\n' && !s2[1])
626 return true;
627 if (*s1 == '\n' && !s1[1] && !*s2)
628 return true;
629 return false;
630}
631EXPORT_SYMBOL(sysfs_streq);
632
Jonathan Camerond0f1fed2011-04-19 12:43:45 +0100633/**
Andy Shevchenko56b06082016-03-17 14:22:14 -0700634 * match_string - matches given string in an array
635 * @array: array of strings
636 * @n: number of strings in the array or -1 for NULL terminated arrays
637 * @string: string to match with
638 *
639 * Return:
640 * index of a @string in the @array if matches, or %-EINVAL otherwise.
641 */
642int match_string(const char * const *array, size_t n, const char *string)
643{
644 int index;
645 const char *item;
646
647 for (index = 0; index < n; index++) {
648 item = array[index];
649 if (!item)
650 break;
651 if (!strcmp(item, string))
652 return index;
653 }
654
655 return -EINVAL;
656}
657EXPORT_SYMBOL(match_string);
658
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659#ifndef __HAVE_ARCH_MEMSET
660/**
661 * memset - Fill a region of memory with the given value
662 * @s: Pointer to the start of the area.
663 * @c: The byte to fill the area with
664 * @count: The size of the area.
665 *
666 * Do not use memset() to access IO space, use memset_io() instead.
667 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800668void *memset(void *s, int c, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669{
Jesper Juhl850b9242005-10-30 15:02:13 -0800670 char *xs = s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671
672 while (count--)
673 *xs++ = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 return s;
675}
676EXPORT_SYMBOL(memset);
677#endif
678
Daniel Borkmannd4c5efd2014-08-26 23:16:35 -0400679/**
680 * memzero_explicit - Fill a region of memory (e.g. sensitive
681 * keying data) with 0s.
682 * @s: Pointer to the start of the area.
683 * @count: The size of the area.
684 *
Daniel Borkmann81553302015-01-06 00:27:45 +0100685 * Note: usually using memset() is just fine (!), but in cases
686 * where clearing out _local_ data at the end of a scope is
687 * necessary, memzero_explicit() should be used instead in
688 * order to prevent the compiler from optimising away zeroing.
689 *
Daniel Borkmannd4c5efd2014-08-26 23:16:35 -0400690 * memzero_explicit() doesn't need an arch-specific version as
691 * it just invokes the one of memset() implicitly.
692 */
693void memzero_explicit(void *s, size_t count)
694{
695 memset(s, 0, count);
Daniel Borkmann7829fb02015-04-30 04:13:52 +0200696 barrier_data(s);
Daniel Borkmannd4c5efd2014-08-26 23:16:35 -0400697}
698EXPORT_SYMBOL(memzero_explicit);
699
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700#ifndef __HAVE_ARCH_MEMCPY
701/**
702 * memcpy - Copy one area of memory to another
703 * @dest: Where to copy to
704 * @src: Where to copy from
705 * @count: The size of the area.
706 *
707 * You should not use this function to access IO space, use memcpy_toio()
708 * or memcpy_fromio() instead.
709 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800710void *memcpy(void *dest, const void *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711{
Jesper Juhl850b9242005-10-30 15:02:13 -0800712 char *tmp = dest;
Jan-Benedict Glaw4c416ab2006-04-10 22:54:09 -0700713 const char *s = src;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714
715 while (count--)
716 *tmp++ = *s++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 return dest;
718}
719EXPORT_SYMBOL(memcpy);
720#endif
721
722#ifndef __HAVE_ARCH_MEMMOVE
723/**
724 * memmove - Copy one area of memory to another
725 * @dest: Where to copy to
726 * @src: Where to copy from
727 * @count: The size of the area.
728 *
729 * Unlike memcpy(), memmove() copes with overlapping areas.
730 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800731void *memmove(void *dest, const void *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732{
Paul Jackson82da2c32005-10-30 15:03:19 -0800733 char *tmp;
734 const char *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735
736 if (dest <= src) {
Jesper Juhl850b9242005-10-30 15:02:13 -0800737 tmp = dest;
738 s = src;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 while (count--)
740 *tmp++ = *s++;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800741 } else {
Jesper Juhl850b9242005-10-30 15:02:13 -0800742 tmp = dest;
743 tmp += count;
744 s = src;
745 s += count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 while (count--)
747 *--tmp = *--s;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800748 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749 return dest;
750}
751EXPORT_SYMBOL(memmove);
752#endif
753
754#ifndef __HAVE_ARCH_MEMCMP
755/**
756 * memcmp - Compare two areas of memory
757 * @cs: One area of memory
758 * @ct: Another area of memory
759 * @count: The size of the area.
760 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700761#undef memcmp
Andi Kleena7330c92014-02-08 08:52:06 +0100762__visible int memcmp(const void *cs, const void *ct, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763{
764 const unsigned char *su1, *su2;
765 int res = 0;
766
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800767 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 if ((res = *su1 - *su2) != 0)
769 break;
770 return res;
771}
772EXPORT_SYMBOL(memcmp);
773#endif
774
Nick Desaulniers7eceaf52019-04-05 18:38:45 -0700775#ifndef __HAVE_ARCH_BCMP
776/**
777 * bcmp - returns 0 if and only if the buffers have identical contents.
778 * @a: pointer to first buffer.
779 * @b: pointer to second buffer.
780 * @len: size of buffers.
781 *
782 * The sign or magnitude of a non-zero return value has no particular
783 * meaning, and architectures may implement their own more efficient bcmp(). So
784 * while this particular implementation is a simple (tail) call to memcmp, do
785 * not rely on anything but whether the return value is zero or non-zero.
786 */
787#undef bcmp
788int bcmp(const void *a, const void *b, size_t len)
789{
790 return memcmp(a, b, len);
791}
792EXPORT_SYMBOL(bcmp);
793#endif
794
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795#ifndef __HAVE_ARCH_MEMSCAN
796/**
797 * memscan - Find a character in an area of memory.
798 * @addr: The memory area
799 * @c: The byte to search for
800 * @size: The size of the area.
801 *
802 * returns the address of the first occurrence of @c, or 1 byte past
803 * the area if @c is not found
804 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800805void *memscan(void *addr, int c, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806{
Jesper Juhl850b9242005-10-30 15:02:13 -0800807 unsigned char *p = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808
809 while (size) {
810 if (*p == c)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800811 return (void *)p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 p++;
813 size--;
814 }
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800815 return (void *)p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816}
817EXPORT_SYMBOL(memscan);
818#endif
819
820#ifndef __HAVE_ARCH_STRSTR
821/**
822 * strstr - Find the first substring in a %NUL terminated string
823 * @s1: The string to be searched
824 * @s2: The string to search for
825 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800826char *strstr(const char *s1, const char *s2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827{
Li Zefand5f1fb52010-01-14 10:53:55 +0800828 size_t l1, l2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829
830 l2 = strlen(s2);
831 if (!l2)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800832 return (char *)s1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 l1 = strlen(s1);
834 while (l1 >= l2) {
835 l1--;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800836 if (!memcmp(s1, s2, l2))
837 return (char *)s1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 s1++;
839 }
840 return NULL;
841}
842EXPORT_SYMBOL(strstr);
843#endif
844
Li Zefand5f1fb52010-01-14 10:53:55 +0800845#ifndef __HAVE_ARCH_STRNSTR
846/**
847 * strnstr - Find the first substring in a length-limited string
848 * @s1: The string to be searched
849 * @s2: The string to search for
850 * @len: the maximum number of characters to search
851 */
852char *strnstr(const char *s1, const char *s2, size_t len)
853{
André Goddard Rosad6a2eed2010-03-05 13:43:12 -0800854 size_t l2;
Li Zefand5f1fb52010-01-14 10:53:55 +0800855
856 l2 = strlen(s2);
857 if (!l2)
858 return (char *)s1;
André Goddard Rosad6a2eed2010-03-05 13:43:12 -0800859 while (len >= l2) {
860 len--;
Li Zefand5f1fb52010-01-14 10:53:55 +0800861 if (!memcmp(s1, s2, l2))
862 return (char *)s1;
863 s1++;
864 }
865 return NULL;
866}
867EXPORT_SYMBOL(strnstr);
868#endif
869
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870#ifndef __HAVE_ARCH_MEMCHR
871/**
872 * memchr - Find a character in an area of memory.
873 * @s: The memory area
874 * @c: The byte to search for
875 * @n: The size of the area.
876 *
877 * returns the address of the first occurrence of @c, or %NULL
878 * if @c is not found
879 */
880void *memchr(const void *s, int c, size_t n)
881{
882 const unsigned char *p = s;
883 while (n-- != 0) {
884 if ((unsigned char)c == *p++) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800885 return (void *)(p - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 }
887 }
888 return NULL;
889}
890EXPORT_SYMBOL(memchr);
891#endif
Akinobu Mita798248202011-10-31 17:08:07 -0700892
893static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
894{
895 while (bytes) {
896 if (*start != value)
897 return (void *)start;
898 start++;
899 bytes--;
900 }
901 return NULL;
902}
903
904/**
905 * memchr_inv - Find an unmatching character in an area of memory.
906 * @start: The memory area
907 * @c: Find a character other than c
908 * @bytes: The size of the area.
909 *
910 * returns the address of the first character other than @c, or %NULL
911 * if the whole buffer contains just @c.
912 */
913void *memchr_inv(const void *start, int c, size_t bytes)
914{
915 u8 value = c;
916 u64 value64;
917 unsigned int words, prefix;
918
919 if (bytes <= 16)
920 return check_bytes8(start, value, bytes);
921
Akinobu Mitaf43804b2012-03-23 15:02:14 -0700922 value64 = value;
Linus Torvalds72d93102014-09-13 11:14:53 -0700923#if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64
Andy Shevchenko3368e8fb2015-11-10 14:45:14 -0800924 value64 *= 0x0101010101010101ULL;
Linus Torvalds72d93102014-09-13 11:14:53 -0700925#elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER)
Akinobu Mitaf43804b2012-03-23 15:02:14 -0700926 value64 *= 0x01010101;
927 value64 |= value64 << 32;
928#else
929 value64 |= value64 << 8;
930 value64 |= value64 << 16;
931 value64 |= value64 << 32;
932#endif
Akinobu Mita798248202011-10-31 17:08:07 -0700933
Akinobu Mitaf43804b2012-03-23 15:02:14 -0700934 prefix = (unsigned long)start % 8;
Akinobu Mita798248202011-10-31 17:08:07 -0700935 if (prefix) {
Akinobu Mitaf43804b2012-03-23 15:02:14 -0700936 u8 *r;
937
938 prefix = 8 - prefix;
939 r = check_bytes8(start, value, prefix);
Akinobu Mita798248202011-10-31 17:08:07 -0700940 if (r)
941 return r;
942 start += prefix;
943 bytes -= prefix;
944 }
945
946 words = bytes / 8;
947
948 while (words) {
949 if (*(u64 *)start != value64)
950 return check_bytes8(start, value, 8);
951 start += 8;
952 words--;
953 }
954
955 return check_bytes8(start, value, bytes % 8);
956}
957EXPORT_SYMBOL(memchr_inv);
Rasmus Villemoes94df2902015-06-25 15:02:22 -0700958
959/**
960 * strreplace - Replace all occurrences of character in string.
961 * @s: The string to operate on.
962 * @old: The character being replaced.
963 * @new: The character @old is replaced with.
964 *
965 * Returns pointer to the nul byte at the end of @s.
966 */
967char *strreplace(char *s, char old, char new)
968{
969 for (; *s; ++s)
970 if (*s == old)
971 *s = new;
972 return s;
973}
974EXPORT_SYMBOL(strreplace);