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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 * stupid library routines.. The optimized versions should generally be found
10 * as inline code in <asm-xx/string.h>
11 *
12 * These are buggy as well..
13 *
14 * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de>
15 * - Added strsep() which will replace strtok() soon (because strsep() is
16 * reentrant and should be faster). Use only strsep() in new code, please.
17 *
18 * * Sat Feb 09 2002, Jason Thomas <jason@topic.com.au>,
19 * Matthew Hawkins <matt@mh.dropbear.id.au>
20 * - Kissed strtok() goodbye
21 */
22
23#include <linux/types.h>
24#include <linux/string.h>
25#include <linux/ctype.h>
26#include <linux/kernel.h>
27#include <linux/export.h>
28#include <linux/bug.h>
29#include <linux/errno.h>
30#include <linux/slab.h>
31
32#include <asm/byteorder.h>
33#include <asm/word-at-a-time.h>
34#include <asm/page.h>
35
36#ifndef __HAVE_ARCH_STRNCASECMP
37/**
38 * strncasecmp - Case insensitive, length-limited string comparison
39 * @s1: One string
40 * @s2: The other string
41 * @len: the maximum number of characters to compare
42 */
43int strncasecmp(const char *s1, const char *s2, size_t len)
44{
45 /* Yes, Virginia, it had better be unsigned */
46 unsigned char c1, c2;
47
48 if (!len)
49 return 0;
50
51 do {
52 c1 = *s1++;
53 c2 = *s2++;
54 if (!c1 || !c2)
55 break;
56 if (c1 == c2)
57 continue;
58 c1 = tolower(c1);
59 c2 = tolower(c2);
60 if (c1 != c2)
61 break;
62 } while (--len);
63 return (int)c1 - (int)c2;
64}
65EXPORT_SYMBOL(strncasecmp);
66#endif
67
68#ifndef __HAVE_ARCH_STRCASECMP
69int strcasecmp(const char *s1, const char *s2)
70{
71 int c1, c2;
72
73 do {
74 c1 = tolower(*s1++);
75 c2 = tolower(*s2++);
76 } while (c1 == c2 && c1 != 0);
77 return c1 - c2;
78}
79EXPORT_SYMBOL(strcasecmp);
80#endif
81
82#ifndef __HAVE_ARCH_STRCPY
83/**
84 * strcpy - Copy a %NUL terminated string
85 * @dest: Where to copy the string to
86 * @src: Where to copy the string from
87 */
88char *strcpy(char *dest, const char *src)
89{
90 char *tmp = dest;
91
92 while ((*dest++ = *src++) != '\0')
93 /* nothing */;
94 return tmp;
95}
96EXPORT_SYMBOL(strcpy);
97#endif
98
99#ifndef __HAVE_ARCH_STRNCPY
100/**
101 * strncpy - Copy a length-limited, C-string
102 * @dest: Where to copy the string to
103 * @src: Where to copy the string from
104 * @count: The maximum number of bytes to copy
105 *
106 * The result is not %NUL-terminated if the source exceeds
107 * @count bytes.
108 *
109 * In the case where the length of @src is less than that of
110 * count, the remainder of @dest will be padded with %NUL.
111 *
112 */
113char *strncpy(char *dest, const char *src, size_t count)
114{
115 char *tmp = dest;
116
117 while (count) {
118 if ((*tmp = *src) != 0)
119 src++;
120 tmp++;
121 count--;
122 }
123 return dest;
124}
125EXPORT_SYMBOL(strncpy);
126#endif
127
128#ifndef __HAVE_ARCH_STRLCPY
129/**
130 * strlcpy - Copy a C-string into a sized buffer
131 * @dest: Where to copy the string to
132 * @src: Where to copy the string from
133 * @size: size of destination buffer
134 *
135 * Compatible with ``*BSD``: the result is always a valid
136 * NUL-terminated string that fits in the buffer (unless,
137 * of course, the buffer size is zero). It does not pad
138 * out the result like strncpy() does.
139 */
140size_t strlcpy(char *dest, const char *src, size_t size)
141{
142 size_t ret = strlen(src);
143
144 if (size) {
145 size_t len = (ret >= size) ? size - 1 : ret;
146 memcpy(dest, src, len);
147 dest[len] = '\0';
148 }
149 return ret;
150}
151EXPORT_SYMBOL(strlcpy);
152#endif
153
154#ifndef __HAVE_ARCH_STRSCPY
155/**
156 * strscpy - Copy a C-string into a sized buffer
157 * @dest: Where to copy the string to
158 * @src: Where to copy the string from
159 * @count: Size of destination buffer
160 *
161 * Copy the string, or as much of it as fits, into the dest buffer. The
162 * behavior is undefined if the string buffers overlap. The destination
163 * buffer is always NUL terminated, unless it's zero-sized.
164 *
165 * Preferred to strlcpy() since the API doesn't require reading memory
166 * from the src string beyond the specified "count" bytes, and since
167 * the return value is easier to error-check than strlcpy()'s.
168 * In addition, the implementation is robust to the string changing out
169 * from underneath it, unlike the current strlcpy() implementation.
170 *
171 * Preferred to strncpy() since it always returns a valid string, and
172 * doesn't unnecessarily force the tail of the destination buffer to be
173 * zeroed. If zeroing is desired please use strscpy_pad().
174 *
175 * Returns:
176 * * The number of characters copied (not including the trailing %NUL)
177 * * -E2BIG if count is 0 or @src was truncated.
178 */
179ssize_t strscpy(char *dest, const char *src, size_t count)
180{
181 const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
182 size_t max = count;
183 long res = 0;
184
185 if (count == 0 || WARN_ON_ONCE(count > INT_MAX))
186 return -E2BIG;
187
188#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
189 /*
190 * If src is unaligned, don't cross a page boundary,
191 * since we don't know if the next page is mapped.
192 */
193 if ((long)src & (sizeof(long) - 1)) {
194 size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1));
195 if (limit < max)
196 max = limit;
197 }
198#else
199 /* If src or dest is unaligned, don't do word-at-a-time. */
200 if (((long) dest | (long) src) & (sizeof(long) - 1))
201 max = 0;
202#endif
203
204 while (max >= sizeof(unsigned long)) {
205 unsigned long c, data;
206
207 c = read_word_at_a_time(src+res);
208 if (has_zero(c, &data, &constants)) {
209 data = prep_zero_mask(c, data, &constants);
210 data = create_zero_mask(data);
211 *(unsigned long *)(dest+res) = c & zero_bytemask(data);
212 return res + find_zero(data);
213 }
214 *(unsigned long *)(dest+res) = c;
215 res += sizeof(unsigned long);
216 count -= sizeof(unsigned long);
217 max -= sizeof(unsigned long);
218 }
219
220 while (count) {
221 char c;
222
223 c = src[res];
224 dest[res] = c;
225 if (!c)
226 return res;
227 res++;
228 count--;
229 }
230
231 /* Hit buffer length without finding a NUL; force NUL-termination. */
232 if (res)
233 dest[res-1] = '\0';
234
235 return -E2BIG;
236}
237EXPORT_SYMBOL(strscpy);
238#endif
239
240/**
241 * strscpy_pad() - Copy a C-string into a sized buffer
242 * @dest: Where to copy the string to
243 * @src: Where to copy the string from
244 * @count: Size of destination buffer
245 *
246 * Copy the string, or as much of it as fits, into the dest buffer. The
247 * behavior is undefined if the string buffers overlap. The destination
248 * buffer is always %NUL terminated, unless it's zero-sized.
249 *
250 * If the source string is shorter than the destination buffer, zeros
251 * the tail of the destination buffer.
252 *
253 * For full explanation of why you may want to consider using the
254 * 'strscpy' functions please see the function docstring for strscpy().
255 *
256 * Returns:
257 * * The number of characters copied (not including the trailing %NUL)
258 * * -E2BIG if count is 0 or @src was truncated.
259 */
260ssize_t strscpy_pad(char *dest, const char *src, size_t count)
261{
262 ssize_t written;
263
264 written = strscpy(dest, src, count);
265 if (written < 0 || written == count - 1)
266 return written;
267
268 memset(dest + written + 1, 0, count - written - 1);
269
270 return written;
271}
272EXPORT_SYMBOL(strscpy_pad);
273
274/**
275 * stpcpy - copy a string from src to dest returning a pointer to the new end
276 * of dest, including src's %NUL-terminator. May overrun dest.
277 * @dest: pointer to end of string being copied into. Must be large enough
278 * to receive copy.
279 * @src: pointer to the beginning of string being copied from. Must not overlap
280 * dest.
281 *
282 * stpcpy differs from strcpy in a key way: the return value is a pointer
283 * to the new %NUL-terminating character in @dest. (For strcpy, the return
284 * value is a pointer to the start of @dest). This interface is considered
285 * unsafe as it doesn't perform bounds checking of the inputs. As such it's
286 * not recommended for usage. Instead, its definition is provided in case
287 * the compiler lowers other libcalls to stpcpy.
288 */
289char *stpcpy(char *__restrict__ dest, const char *__restrict__ src);
290char *stpcpy(char *__restrict__ dest, const char *__restrict__ src)
291{
292 while ((*dest++ = *src++) != '\0')
293 /* nothing */;
294 return --dest;
295}
296EXPORT_SYMBOL(stpcpy);
297
298#ifndef __HAVE_ARCH_STRCAT
299/**
300 * strcat - Append one %NUL-terminated string to another
301 * @dest: The string to be appended to
302 * @src: The string to append to it
303 */
304char *strcat(char *dest, const char *src)
305{
306 char *tmp = dest;
307
308 while (*dest)
309 dest++;
310 while ((*dest++ = *src++) != '\0')
311 ;
312 return tmp;
313}
314EXPORT_SYMBOL(strcat);
315#endif
316
317#ifndef __HAVE_ARCH_STRNCAT
318/**
319 * strncat - Append a length-limited, C-string to another
320 * @dest: The string to be appended to
321 * @src: The string to append to it
322 * @count: The maximum numbers of bytes to copy
323 *
324 * Note that in contrast to strncpy(), strncat() ensures the result is
325 * terminated.
326 */
327char *strncat(char *dest, const char *src, size_t count)
328{
329 char *tmp = dest;
330
331 if (count) {
332 while (*dest)
333 dest++;
334 while ((*dest++ = *src++) != 0) {
335 if (--count == 0) {
336 *dest = '\0';
337 break;
338 }
339 }
340 }
341 return tmp;
342}
343EXPORT_SYMBOL(strncat);
344#endif
345
346#ifndef __HAVE_ARCH_STRLCAT
347/**
348 * strlcat - Append a length-limited, C-string to another
349 * @dest: The string to be appended to
350 * @src: The string to append to it
351 * @count: The size of the destination buffer.
352 */
353size_t strlcat(char *dest, const char *src, size_t count)
354{
355 size_t dsize = strlen(dest);
356 size_t len = strlen(src);
357 size_t res = dsize + len;
358
359 /* This would be a bug */
360 BUG_ON(dsize >= count);
361
362 dest += dsize;
363 count -= dsize;
364 if (len >= count)
365 len = count-1;
366 memcpy(dest, src, len);
367 dest[len] = 0;
368 return res;
369}
370EXPORT_SYMBOL(strlcat);
371#endif
372
373#ifndef __HAVE_ARCH_STRCMP
374/**
375 * strcmp - Compare two strings
376 * @cs: One string
377 * @ct: Another string
378 */
379int strcmp(const char *cs, const char *ct)
380{
381 unsigned char c1, c2;
382
383 while (1) {
384 c1 = *cs++;
385 c2 = *ct++;
386 if (c1 != c2)
387 return c1 < c2 ? -1 : 1;
388 if (!c1)
389 break;
390 }
391 return 0;
392}
393EXPORT_SYMBOL(strcmp);
394#endif
395
396#ifndef __HAVE_ARCH_STRNCMP
397/**
398 * strncmp - Compare two length-limited strings
399 * @cs: One string
400 * @ct: Another string
401 * @count: The maximum number of bytes to compare
402 */
403int strncmp(const char *cs, const char *ct, size_t count)
404{
405 unsigned char c1, c2;
406
407 while (count) {
408 c1 = *cs++;
409 c2 = *ct++;
410 if (c1 != c2)
411 return c1 < c2 ? -1 : 1;
412 if (!c1)
413 break;
414 count--;
415 }
416 return 0;
417}
418EXPORT_SYMBOL(strncmp);
419#endif
420
421#ifndef __HAVE_ARCH_STRCHR
422/**
423 * strchr - Find the first occurrence of a character in a string
424 * @s: The string to be searched
425 * @c: The character to search for
426 *
427 * Note that the %NUL-terminator is considered part of the string, and can
428 * be searched for.
429 */
430char *strchr(const char *s, int c)
431{
432 for (; *s != (char)c; ++s)
433 if (*s == '\0')
434 return NULL;
435 return (char *)s;
436}
437EXPORT_SYMBOL(strchr);
438#endif
439
440#ifndef __HAVE_ARCH_STRCHRNUL
441/**
442 * strchrnul - Find and return a character in a string, or end of string
443 * @s: The string to be searched
444 * @c: The character to search for
445 *
446 * Returns pointer to first occurrence of 'c' in s. If c is not found, then
447 * return a pointer to the null byte at the end of s.
448 */
449char *strchrnul(const char *s, int c)
450{
451 while (*s && *s != (char)c)
452 s++;
453 return (char *)s;
454}
455EXPORT_SYMBOL(strchrnul);
456#endif
457
458/**
459 * strnchrnul - Find and return a character in a length limited string,
460 * or end of string
461 * @s: The string to be searched
462 * @count: The number of characters to be searched
463 * @c: The character to search for
464 *
465 * Returns pointer to the first occurrence of 'c' in s. If c is not found,
466 * then return a pointer to the last character of the string.
467 */
468char *strnchrnul(const char *s, size_t count, int c)
469{
470 while (count-- && *s && *s != (char)c)
471 s++;
472 return (char *)s;
473}
474
475#ifndef __HAVE_ARCH_STRRCHR
476/**
477 * strrchr - Find the last occurrence of a character in a string
478 * @s: The string to be searched
479 * @c: The character to search for
480 */
481char *strrchr(const char *s, int c)
482{
483 const char *last = NULL;
484 do {
485 if (*s == (char)c)
486 last = s;
487 } while (*s++);
488 return (char *)last;
489}
490EXPORT_SYMBOL(strrchr);
491#endif
492
493#ifndef __HAVE_ARCH_STRNCHR
494/**
495 * strnchr - Find a character in a length limited string
496 * @s: The string to be searched
497 * @count: The number of characters to be searched
498 * @c: The character to search for
499 *
500 * Note that the %NUL-terminator is considered part of the string, and can
501 * be searched for.
502 */
503char *strnchr(const char *s, size_t count, int c)
504{
505 while (count--) {
506 if (*s == (char)c)
507 return (char *)s;
508 if (*s++ == '\0')
509 break;
510 }
511 return NULL;
512}
513EXPORT_SYMBOL(strnchr);
514#endif
515
516/**
517 * skip_spaces - Removes leading whitespace from @str.
518 * @str: The string to be stripped.
519 *
520 * Returns a pointer to the first non-whitespace character in @str.
521 */
522char *skip_spaces(const char *str)
523{
524 while (isspace(*str))
525 ++str;
526 return (char *)str;
527}
528EXPORT_SYMBOL(skip_spaces);
529
530/**
531 * strim - Removes leading and trailing whitespace from @s.
532 * @s: The string to be stripped.
533 *
534 * Note that the first trailing whitespace is replaced with a %NUL-terminator
535 * in the given string @s. Returns a pointer to the first non-whitespace
536 * character in @s.
537 */
538char *strim(char *s)
539{
540 size_t size;
541 char *end;
542
543 size = strlen(s);
544 if (!size)
545 return s;
546
547 end = s + size - 1;
548 while (end >= s && isspace(*end))
549 end--;
550 *(end + 1) = '\0';
551
552 return skip_spaces(s);
553}
554EXPORT_SYMBOL(strim);
555
556#ifndef __HAVE_ARCH_STRLEN
557/**
558 * strlen - Find the length of a string
559 * @s: The string to be sized
560 */
561size_t strlen(const char *s)
562{
563 const char *sc;
564
565 for (sc = s; *sc != '\0'; ++sc)
566 /* nothing */;
567 return sc - s;
568}
569EXPORT_SYMBOL(strlen);
570#endif
571
572#ifndef __HAVE_ARCH_STRNLEN
573/**
574 * strnlen - Find the length of a length-limited string
575 * @s: The string to be sized
576 * @count: The maximum number of bytes to search
577 */
578size_t strnlen(const char *s, size_t count)
579{
580 const char *sc;
581
582 for (sc = s; count-- && *sc != '\0'; ++sc)
583 /* nothing */;
584 return sc - s;
585}
586EXPORT_SYMBOL(strnlen);
587#endif
588
589#ifndef __HAVE_ARCH_STRSPN
590/**
591 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
592 * @s: The string to be searched
593 * @accept: The string to search for
594 */
595size_t strspn(const char *s, const char *accept)
596{
597 const char *p;
598 const char *a;
599 size_t count = 0;
600
601 for (p = s; *p != '\0'; ++p) {
602 for (a = accept; *a != '\0'; ++a) {
603 if (*p == *a)
604 break;
605 }
606 if (*a == '\0')
607 return count;
608 ++count;
609 }
610 return count;
611}
612
613EXPORT_SYMBOL(strspn);
614#endif
615
616#ifndef __HAVE_ARCH_STRCSPN
617/**
618 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
619 * @s: The string to be searched
620 * @reject: The string to avoid
621 */
622size_t strcspn(const char *s, const char *reject)
623{
624 const char *p;
625 const char *r;
626 size_t count = 0;
627
628 for (p = s; *p != '\0'; ++p) {
629 for (r = reject; *r != '\0'; ++r) {
630 if (*p == *r)
631 return count;
632 }
633 ++count;
634 }
635 return count;
636}
637EXPORT_SYMBOL(strcspn);
638#endif
639
640#ifndef __HAVE_ARCH_STRPBRK
641/**
642 * strpbrk - Find the first occurrence of a set of characters
643 * @cs: The string to be searched
644 * @ct: The characters to search for
645 */
646char *strpbrk(const char *cs, const char *ct)
647{
648 const char *sc1, *sc2;
649
650 for (sc1 = cs; *sc1 != '\0'; ++sc1) {
651 for (sc2 = ct; *sc2 != '\0'; ++sc2) {
652 if (*sc1 == *sc2)
653 return (char *)sc1;
654 }
655 }
656 return NULL;
657}
658EXPORT_SYMBOL(strpbrk);
659#endif
660
661#ifndef __HAVE_ARCH_STRSEP
662/**
663 * strsep - Split a string into tokens
664 * @s: The string to be searched
665 * @ct: The characters to search for
666 *
667 * strsep() updates @s to point after the token, ready for the next call.
668 *
669 * It returns empty tokens, too, behaving exactly like the libc function
670 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
671 * Same semantics, slimmer shape. ;)
672 */
673char *strsep(char **s, const char *ct)
674{
675 char *sbegin = *s;
676 char *end;
677
678 if (sbegin == NULL)
679 return NULL;
680
681 end = strpbrk(sbegin, ct);
682 if (end)
683 *end++ = '\0';
684 *s = end;
685 return sbegin;
686}
687EXPORT_SYMBOL(strsep);
688#endif
689
690/**
691 * sysfs_streq - return true if strings are equal, modulo trailing newline
692 * @s1: one string
693 * @s2: another string
694 *
695 * This routine returns true iff two strings are equal, treating both
696 * NUL and newline-then-NUL as equivalent string terminations. It's
697 * geared for use with sysfs input strings, which generally terminate
698 * with newlines but are compared against values without newlines.
699 */
700bool sysfs_streq(const char *s1, const char *s2)
701{
702 while (*s1 && *s1 == *s2) {
703 s1++;
704 s2++;
705 }
706
707 if (*s1 == *s2)
708 return true;
709 if (!*s1 && *s2 == '\n' && !s2[1])
710 return true;
711 if (*s1 == '\n' && !s1[1] && !*s2)
712 return true;
713 return false;
714}
715EXPORT_SYMBOL(sysfs_streq);
716
717/**
718 * match_string - matches given string in an array
719 * @array: array of strings
720 * @n: number of strings in the array or -1 for NULL terminated arrays
721 * @string: string to match with
722 *
723 * This routine will look for a string in an array of strings up to the
724 * n-th element in the array or until the first NULL element.
725 *
726 * Historically the value of -1 for @n, was used to search in arrays that
727 * are NULL terminated. However, the function does not make a distinction
728 * when finishing the search: either @n elements have been compared OR
729 * the first NULL element was found.
730 *
731 * Return:
732 * index of a @string in the @array if matches, or %-EINVAL otherwise.
733 */
734int match_string(const char * const *array, size_t n, const char *string)
735{
736 int index;
737 const char *item;
738
739 for (index = 0; index < n; index++) {
740 item = array[index];
741 if (!item)
742 break;
743 if (!strcmp(item, string))
744 return index;
745 }
746
747 return -EINVAL;
748}
749EXPORT_SYMBOL(match_string);
750
751/**
752 * __sysfs_match_string - matches given string in an array
753 * @array: array of strings
754 * @n: number of strings in the array or -1 for NULL terminated arrays
755 * @str: string to match with
756 *
757 * Returns index of @str in the @array or -EINVAL, just like match_string().
758 * Uses sysfs_streq instead of strcmp for matching.
759 *
760 * This routine will look for a string in an array of strings up to the
761 * n-th element in the array or until the first NULL element.
762 *
763 * Historically the value of -1 for @n, was used to search in arrays that
764 * are NULL terminated. However, the function does not make a distinction
765 * when finishing the search: either @n elements have been compared OR
766 * the first NULL element was found.
767 */
768int __sysfs_match_string(const char * const *array, size_t n, const char *str)
769{
770 const char *item;
771 int index;
772
773 for (index = 0; index < n; index++) {
774 item = array[index];
775 if (!item)
776 break;
777 if (sysfs_streq(item, str))
778 return index;
779 }
780
781 return -EINVAL;
782}
783EXPORT_SYMBOL(__sysfs_match_string);
784
785#ifndef __HAVE_ARCH_MEMSET
786/**
787 * memset - Fill a region of memory with the given value
788 * @s: Pointer to the start of the area.
789 * @c: The byte to fill the area with
790 * @count: The size of the area.
791 *
792 * Do not use memset() to access IO space, use memset_io() instead.
793 */
794void *memset(void *s, int c, size_t count)
795{
796 char *xs = s;
797
798 while (count--)
799 *xs++ = c;
800 return s;
801}
802EXPORT_SYMBOL(memset);
803#endif
804
805#ifndef __HAVE_ARCH_MEMSET16
806/**
807 * memset16() - Fill a memory area with a uint16_t
808 * @s: Pointer to the start of the area.
809 * @v: The value to fill the area with
810 * @count: The number of values to store
811 *
812 * Differs from memset() in that it fills with a uint16_t instead
813 * of a byte. Remember that @count is the number of uint16_ts to
814 * store, not the number of bytes.
815 */
816void *memset16(uint16_t *s, uint16_t v, size_t count)
817{
818 uint16_t *xs = s;
819
820 while (count--)
821 *xs++ = v;
822 return s;
823}
824EXPORT_SYMBOL(memset16);
825#endif
826
827#ifndef __HAVE_ARCH_MEMSET32
828/**
829 * memset32() - Fill a memory area with a uint32_t
830 * @s: Pointer to the start of the area.
831 * @v: The value to fill the area with
832 * @count: The number of values to store
833 *
834 * Differs from memset() in that it fills with a uint32_t instead
835 * of a byte. Remember that @count is the number of uint32_ts to
836 * store, not the number of bytes.
837 */
838void *memset32(uint32_t *s, uint32_t v, size_t count)
839{
840 uint32_t *xs = s;
841
842 while (count--)
843 *xs++ = v;
844 return s;
845}
846EXPORT_SYMBOL(memset32);
847#endif
848
849#ifndef __HAVE_ARCH_MEMSET64
850/**
851 * memset64() - Fill a memory area with a uint64_t
852 * @s: Pointer to the start of the area.
853 * @v: The value to fill the area with
854 * @count: The number of values to store
855 *
856 * Differs from memset() in that it fills with a uint64_t instead
857 * of a byte. Remember that @count is the number of uint64_ts to
858 * store, not the number of bytes.
859 */
860void *memset64(uint64_t *s, uint64_t v, size_t count)
861{
862 uint64_t *xs = s;
863
864 while (count--)
865 *xs++ = v;
866 return s;
867}
868EXPORT_SYMBOL(memset64);
869#endif
870
871#ifndef __HAVE_ARCH_MEMCPY
872/**
873 * memcpy - Copy one area of memory to another
874 * @dest: Where to copy to
875 * @src: Where to copy from
876 * @count: The size of the area.
877 *
878 * You should not use this function to access IO space, use memcpy_toio()
879 * or memcpy_fromio() instead.
880 */
881void *memcpy(void *dest, const void *src, size_t count)
882{
883 char *tmp = dest;
884 const char *s = src;
885
886 while (count--)
887 *tmp++ = *s++;
888 return dest;
889}
890EXPORT_SYMBOL(memcpy);
891#endif
892
893#ifndef __HAVE_ARCH_MEMMOVE
894/**
895 * memmove - Copy one area of memory to another
896 * @dest: Where to copy to
897 * @src: Where to copy from
898 * @count: The size of the area.
899 *
900 * Unlike memcpy(), memmove() copes with overlapping areas.
901 */
902void *memmove(void *dest, const void *src, size_t count)
903{
904 char *tmp;
905 const char *s;
906
907 if (dest <= src) {
908 tmp = dest;
909 s = src;
910 while (count--)
911 *tmp++ = *s++;
912 } else {
913 tmp = dest;
914 tmp += count;
915 s = src;
916 s += count;
917 while (count--)
918 *--tmp = *--s;
919 }
920 return dest;
921}
922EXPORT_SYMBOL(memmove);
923#endif
924
925#ifndef __HAVE_ARCH_MEMCMP
926/**
927 * memcmp - Compare two areas of memory
928 * @cs: One area of memory
929 * @ct: Another area of memory
930 * @count: The size of the area.
931 */
932#undef memcmp
933__visible int memcmp(const void *cs, const void *ct, size_t count)
934{
935 const unsigned char *su1, *su2;
936 int res = 0;
937
938 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
939 if ((res = *su1 - *su2) != 0)
940 break;
941 return res;
942}
943EXPORT_SYMBOL(memcmp);
944#endif
945
946#ifndef __HAVE_ARCH_BCMP
947/**
948 * bcmp - returns 0 if and only if the buffers have identical contents.
949 * @a: pointer to first buffer.
950 * @b: pointer to second buffer.
951 * @len: size of buffers.
952 *
953 * The sign or magnitude of a non-zero return value has no particular
954 * meaning, and architectures may implement their own more efficient bcmp(). So
955 * while this particular implementation is a simple (tail) call to memcmp, do
956 * not rely on anything but whether the return value is zero or non-zero.
957 */
958int bcmp(const void *a, const void *b, size_t len)
959{
960 return memcmp(a, b, len);
961}
962EXPORT_SYMBOL(bcmp);
963#endif
964
965#ifndef __HAVE_ARCH_MEMSCAN
966/**
967 * memscan - Find a character in an area of memory.
968 * @addr: The memory area
969 * @c: The byte to search for
970 * @size: The size of the area.
971 *
972 * returns the address of the first occurrence of @c, or 1 byte past
973 * the area if @c is not found
974 */
975void *memscan(void *addr, int c, size_t size)
976{
977 unsigned char *p = addr;
978
979 while (size) {
980 if (*p == (unsigned char)c)
981 return (void *)p;
982 p++;
983 size--;
984 }
985 return (void *)p;
986}
987EXPORT_SYMBOL(memscan);
988#endif
989
990#ifndef __HAVE_ARCH_STRSTR
991/**
992 * strstr - Find the first substring in a %NUL terminated string
993 * @s1: The string to be searched
994 * @s2: The string to search for
995 */
996char *strstr(const char *s1, const char *s2)
997{
998 size_t l1, l2;
999
1000 l2 = strlen(s2);
1001 if (!l2)
1002 return (char *)s1;
1003 l1 = strlen(s1);
1004 while (l1 >= l2) {
1005 l1--;
1006 if (!memcmp(s1, s2, l2))
1007 return (char *)s1;
1008 s1++;
1009 }
1010 return NULL;
1011}
1012EXPORT_SYMBOL(strstr);
1013#endif
1014
1015#ifndef __HAVE_ARCH_STRNSTR
1016/**
1017 * strnstr - Find the first substring in a length-limited string
1018 * @s1: The string to be searched
1019 * @s2: The string to search for
1020 * @len: the maximum number of characters to search
1021 */
1022char *strnstr(const char *s1, const char *s2, size_t len)
1023{
1024 size_t l2;
1025
1026 l2 = strlen(s2);
1027 if (!l2)
1028 return (char *)s1;
1029 while (len >= l2) {
1030 len--;
1031 if (!memcmp(s1, s2, l2))
1032 return (char *)s1;
1033 s1++;
1034 }
1035 return NULL;
1036}
1037EXPORT_SYMBOL(strnstr);
1038#endif
1039
1040#ifndef __HAVE_ARCH_MEMCHR
1041/**
1042 * memchr - Find a character in an area of memory.
1043 * @s: The memory area
1044 * @c: The byte to search for
1045 * @n: The size of the area.
1046 *
1047 * returns the address of the first occurrence of @c, or %NULL
1048 * if @c is not found
1049 */
1050void *memchr(const void *s, int c, size_t n)
1051{
1052 const unsigned char *p = s;
1053 while (n-- != 0) {
1054 if ((unsigned char)c == *p++) {
1055 return (void *)(p - 1);
1056 }
1057 }
1058 return NULL;
1059}
1060EXPORT_SYMBOL(memchr);
1061#endif
1062
1063static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
1064{
1065 while (bytes) {
1066 if (*start != value)
1067 return (void *)start;
1068 start++;
1069 bytes--;
1070 }
1071 return NULL;
1072}
1073
1074/**
1075 * memchr_inv - Find an unmatching character in an area of memory.
1076 * @start: The memory area
1077 * @c: Find a character other than c
1078 * @bytes: The size of the area.
1079 *
1080 * returns the address of the first character other than @c, or %NULL
1081 * if the whole buffer contains just @c.
1082 */
1083void *memchr_inv(const void *start, int c, size_t bytes)
1084{
1085 u8 value = c;
1086 u64 value64;
1087 unsigned int words, prefix;
1088
1089 if (bytes <= 16)
1090 return check_bytes8(start, value, bytes);
1091
1092 value64 = value;
1093#if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64
1094 value64 *= 0x0101010101010101ULL;
1095#elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER)
1096 value64 *= 0x01010101;
1097 value64 |= value64 << 32;
1098#else
1099 value64 |= value64 << 8;
1100 value64 |= value64 << 16;
1101 value64 |= value64 << 32;
1102#endif
1103
1104 prefix = (unsigned long)start % 8;
1105 if (prefix) {
1106 u8 *r;
1107
1108 prefix = 8 - prefix;
1109 r = check_bytes8(start, value, prefix);
1110 if (r)
1111 return r;
1112 start += prefix;
1113 bytes -= prefix;
1114 }
1115
1116 words = bytes / 8;
1117
1118 while (words) {
1119 if (*(u64 *)start != value64)
1120 return check_bytes8(start, value, 8);
1121 start += 8;
1122 words--;
1123 }
1124
1125 return check_bytes8(start, value, bytes % 8);
1126}
1127EXPORT_SYMBOL(memchr_inv);
1128
1129/**
1130 * strreplace - Replace all occurrences of character in string.
1131 * @s: The string to operate on.
1132 * @old: The character being replaced.
1133 * @new: The character @old is replaced with.
1134 *
1135 * Returns pointer to the nul byte at the end of @s.
1136 */
1137char *strreplace(char *s, char old, char new)
1138{
1139 for (; *s; ++s)
1140 if (*s == old)
1141 *s = new;
1142 return s;
1143}
1144EXPORT_SYMBOL(strreplace);
1145
1146void fortify_panic(const char *name)
1147{
1148 pr_emerg("detected buffer overflow in %s\n", name);
1149 BUG();
1150}
1151EXPORT_SYMBOL(fortify_panic);
1/*
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>
25#include <linux/kernel.h>
26#include <linux/export.h>
27#include <linux/bug.h>
28#include <linux/errno.h>
29
30#include <asm/byteorder.h>
31#include <asm/word-at-a-time.h>
32#include <asm/page.h>
33
34#ifndef __HAVE_ARCH_STRNCASECMP
35/**
36 * strncasecmp - Case insensitive, length-limited string comparison
37 * @s1: One string
38 * @s2: The other string
39 * @len: the maximum number of characters to compare
40 */
41int strncasecmp(const char *s1, const char *s2, size_t len)
42{
43 /* Yes, Virginia, it had better be unsigned */
44 unsigned char c1, c2;
45
46 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);
61 return (int)c1 - (int)c2;
62}
63EXPORT_SYMBOL(strncasecmp);
64#endif
65
66#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
80#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 */
86#undef strcpy
87char *strcpy(char *dest, const char *src)
88{
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/**
100 * strncpy - Copy a length-limited, C-string
101 * @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.
107 *
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 *
111 */
112char *strncpy(char *dest, const char *src, size_t count)
113{
114 char *tmp = dest;
115
116 while (count) {
117 if ((*tmp = *src) != 0)
118 src++;
119 tmp++;
120 count--;
121 }
122 return dest;
123}
124EXPORT_SYMBOL(strncpy);
125#endif
126
127#ifndef __HAVE_ARCH_STRLCPY
128/**
129 * strlcpy - Copy a C-string into a sized buffer
130 * @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) {
144 size_t len = (ret >= size) ? size - 1 : ret;
145 memcpy(dest, src, len);
146 dest[len] = '\0';
147 }
148 return ret;
149}
150EXPORT_SYMBOL(strlcpy);
151#endif
152
153#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
205 c = *(unsigned long *)(src+res);
206 if (has_zero(c, &data, &constants)) {
207 data = prep_zero_mask(c, data, &constants);
208 data = create_zero_mask(data);
209 *(unsigned long *)(dest+res) = c & zero_bytemask(data);
210 return res + find_zero(data);
211 }
212 *(unsigned long *)(dest+res) = c;
213 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
238#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 */
244#undef strcat
245char *strcat(char *dest, const char *src)
246{
247 char *tmp = dest;
248
249 while (*dest)
250 dest++;
251 while ((*dest++ = *src++) != '\0')
252 ;
253 return tmp;
254}
255EXPORT_SYMBOL(strcat);
256#endif
257
258#ifndef __HAVE_ARCH_STRNCAT
259/**
260 * strncat - Append a length-limited, C-string to another
261 * @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 *
265 * Note that in contrast to strncpy(), strncat() ensures the result is
266 * terminated.
267 */
268char *strncat(char *dest, const char *src, size_t count)
269{
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 }
282 return tmp;
283}
284EXPORT_SYMBOL(strncat);
285#endif
286
287#ifndef __HAVE_ARCH_STRLCAT
288/**
289 * strlcat - Append a length-limited, C-string to another
290 * @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 */
320#undef strcmp
321int strcmp(const char *cs, const char *ct)
322{
323 unsigned char c1, c2;
324
325 while (1) {
326 c1 = *cs++;
327 c2 = *ct++;
328 if (c1 != c2)
329 return c1 < c2 ? -1 : 1;
330 if (!c1)
331 break;
332 }
333 return 0;
334}
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 */
345int strncmp(const char *cs, const char *ct, size_t count)
346{
347 unsigned char c1, c2;
348
349 while (count) {
350 c1 = *cs++;
351 c2 = *ct++;
352 if (c1 != c2)
353 return c1 < c2 ? -1 : 1;
354 if (!c1)
355 break;
356 count--;
357 }
358 return 0;
359}
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 */
369char *strchr(const char *s, int c)
370{
371 for (; *s != (char)c; ++s)
372 if (*s == '\0')
373 return NULL;
374 return (char *)s;
375}
376EXPORT_SYMBOL(strchr);
377#endif
378
379#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
397#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 */
403char *strrchr(const char *s, int c)
404{
405 const char *last = NULL;
406 do {
407 if (*s == (char)c)
408 last = s;
409 } while (*s++);
410 return (char *)last;
411}
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)
425 if (*s == (char)c)
426 return (char *)s;
427 return NULL;
428}
429EXPORT_SYMBOL(strnchr);
430#endif
431
432/**
433 * skip_spaces - Removes leading whitespace from @str.
434 * @str: The string to be stripped.
435 *
436 * Returns a pointer to the first non-whitespace character in @str.
437 */
438char *skip_spaces(const char *str)
439{
440 while (isspace(*str))
441 ++str;
442 return (char *)str;
443}
444EXPORT_SYMBOL(skip_spaces);
445
446/**
447 * strim - Removes leading and trailing whitespace from @s.
448 * @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 */
454char *strim(char *s)
455{
456 size_t size;
457 char *end;
458
459 size = strlen(s);
460 if (!size)
461 return s;
462
463 end = s + size - 1;
464 while (end >= s && isspace(*end))
465 end--;
466 *(end + 1) = '\0';
467
468 return skip_spaces(s);
469}
470EXPORT_SYMBOL(strim);
471
472#ifndef __HAVE_ARCH_STRLEN
473/**
474 * strlen - Find the length of a string
475 * @s: The string to be sized
476 */
477size_t strlen(const char *s)
478{
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 */
494size_t strnlen(const char *s, size_t count)
495{
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/**
507 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
508 * @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 }
526 return count;
527}
528
529EXPORT_SYMBOL(strspn);
530#endif
531
532#ifndef __HAVE_ARCH_STRCSPN
533/**
534 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
535 * @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 }
551 return count;
552}
553EXPORT_SYMBOL(strcspn);
554#endif
555
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 */
562char *strpbrk(const char *cs, const char *ct)
563{
564 const char *sc1, *sc2;
565
566 for (sc1 = cs; *sc1 != '\0'; ++sc1) {
567 for (sc2 = ct; *sc2 != '\0'; ++sc2) {
568 if (*sc1 == *sc2)
569 return (char *)sc1;
570 }
571 }
572 return NULL;
573}
574EXPORT_SYMBOL(strpbrk);
575#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 */
589char *strsep(char **s, const char *ct)
590{
591 char *sbegin = *s;
592 char *end;
593
594 if (sbegin == NULL)
595 return NULL;
596
597 end = strpbrk(sbegin, ct);
598 if (end)
599 *end++ = '\0';
600 *s = end;
601 return sbegin;
602}
603EXPORT_SYMBOL(strsep);
604#endif
605
606/**
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
633/**
634 * 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
659#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 */
668void *memset(void *s, int c, size_t count)
669{
670 char *xs = s;
671
672 while (count--)
673 *xs++ = c;
674 return s;
675}
676EXPORT_SYMBOL(memset);
677#endif
678
679/**
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 *
685 * 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 *
690 * 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);
696 barrier_data(s);
697}
698EXPORT_SYMBOL(memzero_explicit);
699
700#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 */
710void *memcpy(void *dest, const void *src, size_t count)
711{
712 char *tmp = dest;
713 const char *s = src;
714
715 while (count--)
716 *tmp++ = *s++;
717 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 */
731void *memmove(void *dest, const void *src, size_t count)
732{
733 char *tmp;
734 const char *s;
735
736 if (dest <= src) {
737 tmp = dest;
738 s = src;
739 while (count--)
740 *tmp++ = *s++;
741 } else {
742 tmp = dest;
743 tmp += count;
744 s = src;
745 s += count;
746 while (count--)
747 *--tmp = *--s;
748 }
749 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 */
761#undef memcmp
762__visible int memcmp(const void *cs, const void *ct, size_t count)
763{
764 const unsigned char *su1, *su2;
765 int res = 0;
766
767 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
768 if ((res = *su1 - *su2) != 0)
769 break;
770 return res;
771}
772EXPORT_SYMBOL(memcmp);
773#endif
774
775#ifndef __HAVE_ARCH_MEMSCAN
776/**
777 * memscan - Find a character in an area of memory.
778 * @addr: The memory area
779 * @c: The byte to search for
780 * @size: The size of the area.
781 *
782 * returns the address of the first occurrence of @c, or 1 byte past
783 * the area if @c is not found
784 */
785void *memscan(void *addr, int c, size_t size)
786{
787 unsigned char *p = addr;
788
789 while (size) {
790 if (*p == c)
791 return (void *)p;
792 p++;
793 size--;
794 }
795 return (void *)p;
796}
797EXPORT_SYMBOL(memscan);
798#endif
799
800#ifndef __HAVE_ARCH_STRSTR
801/**
802 * strstr - Find the first substring in a %NUL terminated string
803 * @s1: The string to be searched
804 * @s2: The string to search for
805 */
806char *strstr(const char *s1, const char *s2)
807{
808 size_t l1, l2;
809
810 l2 = strlen(s2);
811 if (!l2)
812 return (char *)s1;
813 l1 = strlen(s1);
814 while (l1 >= l2) {
815 l1--;
816 if (!memcmp(s1, s2, l2))
817 return (char *)s1;
818 s1++;
819 }
820 return NULL;
821}
822EXPORT_SYMBOL(strstr);
823#endif
824
825#ifndef __HAVE_ARCH_STRNSTR
826/**
827 * strnstr - Find the first substring in a length-limited string
828 * @s1: The string to be searched
829 * @s2: The string to search for
830 * @len: the maximum number of characters to search
831 */
832char *strnstr(const char *s1, const char *s2, size_t len)
833{
834 size_t l2;
835
836 l2 = strlen(s2);
837 if (!l2)
838 return (char *)s1;
839 while (len >= l2) {
840 len--;
841 if (!memcmp(s1, s2, l2))
842 return (char *)s1;
843 s1++;
844 }
845 return NULL;
846}
847EXPORT_SYMBOL(strnstr);
848#endif
849
850#ifndef __HAVE_ARCH_MEMCHR
851/**
852 * memchr - Find a character in an area of memory.
853 * @s: The memory area
854 * @c: The byte to search for
855 * @n: The size of the area.
856 *
857 * returns the address of the first occurrence of @c, or %NULL
858 * if @c is not found
859 */
860void *memchr(const void *s, int c, size_t n)
861{
862 const unsigned char *p = s;
863 while (n-- != 0) {
864 if ((unsigned char)c == *p++) {
865 return (void *)(p - 1);
866 }
867 }
868 return NULL;
869}
870EXPORT_SYMBOL(memchr);
871#endif
872
873static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
874{
875 while (bytes) {
876 if (*start != value)
877 return (void *)start;
878 start++;
879 bytes--;
880 }
881 return NULL;
882}
883
884/**
885 * memchr_inv - Find an unmatching character in an area of memory.
886 * @start: The memory area
887 * @c: Find a character other than c
888 * @bytes: The size of the area.
889 *
890 * returns the address of the first character other than @c, or %NULL
891 * if the whole buffer contains just @c.
892 */
893void *memchr_inv(const void *start, int c, size_t bytes)
894{
895 u8 value = c;
896 u64 value64;
897 unsigned int words, prefix;
898
899 if (bytes <= 16)
900 return check_bytes8(start, value, bytes);
901
902 value64 = value;
903#if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64
904 value64 *= 0x0101010101010101ULL;
905#elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER)
906 value64 *= 0x01010101;
907 value64 |= value64 << 32;
908#else
909 value64 |= value64 << 8;
910 value64 |= value64 << 16;
911 value64 |= value64 << 32;
912#endif
913
914 prefix = (unsigned long)start % 8;
915 if (prefix) {
916 u8 *r;
917
918 prefix = 8 - prefix;
919 r = check_bytes8(start, value, prefix);
920 if (r)
921 return r;
922 start += prefix;
923 bytes -= prefix;
924 }
925
926 words = bytes / 8;
927
928 while (words) {
929 if (*(u64 *)start != value64)
930 return check_bytes8(start, value, 8);
931 start += 8;
932 words--;
933 }
934
935 return check_bytes8(start, value, bytes % 8);
936}
937EXPORT_SYMBOL(memchr_inv);
938
939/**
940 * strreplace - Replace all occurrences of character in string.
941 * @s: The string to operate on.
942 * @old: The character being replaced.
943 * @new: The character @old is replaced with.
944 *
945 * Returns pointer to the nul byte at the end of @s.
946 */
947char *strreplace(char *s, char old, char new)
948{
949 for (; *s; ++s)
950 if (*s == old)
951 *s = new;
952 return s;
953}
954EXPORT_SYMBOL(strreplace);