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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);
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/module.h>
26
27#ifndef __HAVE_ARCH_STRNICMP
28/**
29 * strnicmp - Case insensitive, length-limited string comparison
30 * @s1: One string
31 * @s2: The other string
32 * @len: the maximum number of characters to compare
33 */
34int strnicmp(const char *s1, const char *s2, size_t len)
35{
36 /* Yes, Virginia, it had better be unsigned */
37 unsigned char c1, c2;
38
39 if (!len)
40 return 0;
41
42 do {
43 c1 = *s1++;
44 c2 = *s2++;
45 if (!c1 || !c2)
46 break;
47 if (c1 == c2)
48 continue;
49 c1 = tolower(c1);
50 c2 = tolower(c2);
51 if (c1 != c2)
52 break;
53 } while (--len);
54 return (int)c1 - (int)c2;
55}
56EXPORT_SYMBOL(strnicmp);
57#endif
58
59#ifndef __HAVE_ARCH_STRCASECMP
60int strcasecmp(const char *s1, const char *s2)
61{
62 int c1, c2;
63
64 do {
65 c1 = tolower(*s1++);
66 c2 = tolower(*s2++);
67 } while (c1 == c2 && c1 != 0);
68 return c1 - c2;
69}
70EXPORT_SYMBOL(strcasecmp);
71#endif
72
73#ifndef __HAVE_ARCH_STRNCASECMP
74int strncasecmp(const char *s1, const char *s2, size_t n)
75{
76 int c1, c2;
77
78 do {
79 c1 = tolower(*s1++);
80 c2 = tolower(*s2++);
81 } while ((--n > 0) && c1 == c2 && c1 != 0);
82 return c1 - c2;
83}
84EXPORT_SYMBOL(strncasecmp);
85#endif
86
87#ifndef __HAVE_ARCH_STRCPY
88/**
89 * strcpy - Copy a %NUL terminated string
90 * @dest: Where to copy the string to
91 * @src: Where to copy the string from
92 */
93#undef strcpy
94char *strcpy(char *dest, const char *src)
95{
96 char *tmp = dest;
97
98 while ((*dest++ = *src++) != '\0')
99 /* nothing */;
100 return tmp;
101}
102EXPORT_SYMBOL(strcpy);
103#endif
104
105#ifndef __HAVE_ARCH_STRNCPY
106/**
107 * strncpy - Copy a length-limited, %NUL-terminated string
108 * @dest: Where to copy the string to
109 * @src: Where to copy the string from
110 * @count: The maximum number of bytes to copy
111 *
112 * The result is not %NUL-terminated if the source exceeds
113 * @count bytes.
114 *
115 * In the case where the length of @src is less than that of
116 * count, the remainder of @dest will be padded with %NUL.
117 *
118 */
119char *strncpy(char *dest, const char *src, size_t count)
120{
121 char *tmp = dest;
122
123 while (count) {
124 if ((*tmp = *src) != 0)
125 src++;
126 tmp++;
127 count--;
128 }
129 return dest;
130}
131EXPORT_SYMBOL(strncpy);
132#endif
133
134#ifndef __HAVE_ARCH_STRLCPY
135/**
136 * strlcpy - Copy a %NUL terminated string into a sized buffer
137 * @dest: Where to copy the string to
138 * @src: Where to copy the string from
139 * @size: size of destination buffer
140 *
141 * Compatible with *BSD: the result is always a valid
142 * NUL-terminated string that fits in the buffer (unless,
143 * of course, the buffer size is zero). It does not pad
144 * out the result like strncpy() does.
145 */
146size_t strlcpy(char *dest, const char *src, size_t size)
147{
148 size_t ret = strlen(src);
149
150 if (size) {
151 size_t len = (ret >= size) ? size - 1 : ret;
152 memcpy(dest, src, len);
153 dest[len] = '\0';
154 }
155 return ret;
156}
157EXPORT_SYMBOL(strlcpy);
158#endif
159
160#ifndef __HAVE_ARCH_STRCAT
161/**
162 * strcat - Append one %NUL-terminated string to another
163 * @dest: The string to be appended to
164 * @src: The string to append to it
165 */
166#undef strcat
167char *strcat(char *dest, const char *src)
168{
169 char *tmp = dest;
170
171 while (*dest)
172 dest++;
173 while ((*dest++ = *src++) != '\0')
174 ;
175 return tmp;
176}
177EXPORT_SYMBOL(strcat);
178#endif
179
180#ifndef __HAVE_ARCH_STRNCAT
181/**
182 * strncat - Append a length-limited, %NUL-terminated string to another
183 * @dest: The string to be appended to
184 * @src: The string to append to it
185 * @count: The maximum numbers of bytes to copy
186 *
187 * Note that in contrast to strncpy(), strncat() ensures the result is
188 * terminated.
189 */
190char *strncat(char *dest, const char *src, size_t count)
191{
192 char *tmp = dest;
193
194 if (count) {
195 while (*dest)
196 dest++;
197 while ((*dest++ = *src++) != 0) {
198 if (--count == 0) {
199 *dest = '\0';
200 break;
201 }
202 }
203 }
204 return tmp;
205}
206EXPORT_SYMBOL(strncat);
207#endif
208
209#ifndef __HAVE_ARCH_STRLCAT
210/**
211 * strlcat - Append a length-limited, %NUL-terminated string to another
212 * @dest: The string to be appended to
213 * @src: The string to append to it
214 * @count: The size of the destination buffer.
215 */
216size_t strlcat(char *dest, const char *src, size_t count)
217{
218 size_t dsize = strlen(dest);
219 size_t len = strlen(src);
220 size_t res = dsize + len;
221
222 /* This would be a bug */
223 BUG_ON(dsize >= count);
224
225 dest += dsize;
226 count -= dsize;
227 if (len >= count)
228 len = count-1;
229 memcpy(dest, src, len);
230 dest[len] = 0;
231 return res;
232}
233EXPORT_SYMBOL(strlcat);
234#endif
235
236#ifndef __HAVE_ARCH_STRCMP
237/**
238 * strcmp - Compare two strings
239 * @cs: One string
240 * @ct: Another string
241 */
242#undef strcmp
243int strcmp(const char *cs, const char *ct)
244{
245 unsigned char c1, c2;
246
247 while (1) {
248 c1 = *cs++;
249 c2 = *ct++;
250 if (c1 != c2)
251 return c1 < c2 ? -1 : 1;
252 if (!c1)
253 break;
254 }
255 return 0;
256}
257EXPORT_SYMBOL(strcmp);
258#endif
259
260#ifndef __HAVE_ARCH_STRNCMP
261/**
262 * strncmp - Compare two length-limited strings
263 * @cs: One string
264 * @ct: Another string
265 * @count: The maximum number of bytes to compare
266 */
267int strncmp(const char *cs, const char *ct, size_t count)
268{
269 unsigned char c1, c2;
270
271 while (count) {
272 c1 = *cs++;
273 c2 = *ct++;
274 if (c1 != c2)
275 return c1 < c2 ? -1 : 1;
276 if (!c1)
277 break;
278 count--;
279 }
280 return 0;
281}
282EXPORT_SYMBOL(strncmp);
283#endif
284
285#ifndef __HAVE_ARCH_STRCHR
286/**
287 * strchr - Find the first occurrence of a character in a string
288 * @s: The string to be searched
289 * @c: The character to search for
290 */
291char *strchr(const char *s, int c)
292{
293 for (; *s != (char)c; ++s)
294 if (*s == '\0')
295 return NULL;
296 return (char *)s;
297}
298EXPORT_SYMBOL(strchr);
299#endif
300
301#ifndef __HAVE_ARCH_STRRCHR
302/**
303 * strrchr - Find the last occurrence of a character in a string
304 * @s: The string to be searched
305 * @c: The character to search for
306 */
307char *strrchr(const char *s, int c)
308{
309 const char *p = s + strlen(s);
310 do {
311 if (*p == (char)c)
312 return (char *)p;
313 } while (--p >= s);
314 return NULL;
315}
316EXPORT_SYMBOL(strrchr);
317#endif
318
319#ifndef __HAVE_ARCH_STRNCHR
320/**
321 * strnchr - Find a character in a length limited string
322 * @s: The string to be searched
323 * @count: The number of characters to be searched
324 * @c: The character to search for
325 */
326char *strnchr(const char *s, size_t count, int c)
327{
328 for (; count-- && *s != '\0'; ++s)
329 if (*s == (char)c)
330 return (char *)s;
331 return NULL;
332}
333EXPORT_SYMBOL(strnchr);
334#endif
335
336/**
337 * skip_spaces - Removes leading whitespace from @str.
338 * @str: The string to be stripped.
339 *
340 * Returns a pointer to the first non-whitespace character in @str.
341 */
342char *skip_spaces(const char *str)
343{
344 while (isspace(*str))
345 ++str;
346 return (char *)str;
347}
348EXPORT_SYMBOL(skip_spaces);
349
350/**
351 * strim - Removes leading and trailing whitespace from @s.
352 * @s: The string to be stripped.
353 *
354 * Note that the first trailing whitespace is replaced with a %NUL-terminator
355 * in the given string @s. Returns a pointer to the first non-whitespace
356 * character in @s.
357 */
358char *strim(char *s)
359{
360 size_t size;
361 char *end;
362
363 s = skip_spaces(s);
364 size = strlen(s);
365 if (!size)
366 return s;
367
368 end = s + size - 1;
369 while (end >= s && isspace(*end))
370 end--;
371 *(end + 1) = '\0';
372
373 return s;
374}
375EXPORT_SYMBOL(strim);
376
377#ifndef __HAVE_ARCH_STRLEN
378/**
379 * strlen - Find the length of a string
380 * @s: The string to be sized
381 */
382size_t strlen(const char *s)
383{
384 const char *sc;
385
386 for (sc = s; *sc != '\0'; ++sc)
387 /* nothing */;
388 return sc - s;
389}
390EXPORT_SYMBOL(strlen);
391#endif
392
393#ifndef __HAVE_ARCH_STRNLEN
394/**
395 * strnlen - Find the length of a length-limited string
396 * @s: The string to be sized
397 * @count: The maximum number of bytes to search
398 */
399size_t strnlen(const char *s, size_t count)
400{
401 const char *sc;
402
403 for (sc = s; count-- && *sc != '\0'; ++sc)
404 /* nothing */;
405 return sc - s;
406}
407EXPORT_SYMBOL(strnlen);
408#endif
409
410#ifndef __HAVE_ARCH_STRSPN
411/**
412 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
413 * @s: The string to be searched
414 * @accept: The string to search for
415 */
416size_t strspn(const char *s, const char *accept)
417{
418 const char *p;
419 const char *a;
420 size_t count = 0;
421
422 for (p = s; *p != '\0'; ++p) {
423 for (a = accept; *a != '\0'; ++a) {
424 if (*p == *a)
425 break;
426 }
427 if (*a == '\0')
428 return count;
429 ++count;
430 }
431 return count;
432}
433
434EXPORT_SYMBOL(strspn);
435#endif
436
437#ifndef __HAVE_ARCH_STRCSPN
438/**
439 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
440 * @s: The string to be searched
441 * @reject: The string to avoid
442 */
443size_t strcspn(const char *s, const char *reject)
444{
445 const char *p;
446 const char *r;
447 size_t count = 0;
448
449 for (p = s; *p != '\0'; ++p) {
450 for (r = reject; *r != '\0'; ++r) {
451 if (*p == *r)
452 return count;
453 }
454 ++count;
455 }
456 return count;
457}
458EXPORT_SYMBOL(strcspn);
459#endif
460
461#ifndef __HAVE_ARCH_STRPBRK
462/**
463 * strpbrk - Find the first occurrence of a set of characters
464 * @cs: The string to be searched
465 * @ct: The characters to search for
466 */
467char *strpbrk(const char *cs, const char *ct)
468{
469 const char *sc1, *sc2;
470
471 for (sc1 = cs; *sc1 != '\0'; ++sc1) {
472 for (sc2 = ct; *sc2 != '\0'; ++sc2) {
473 if (*sc1 == *sc2)
474 return (char *)sc1;
475 }
476 }
477 return NULL;
478}
479EXPORT_SYMBOL(strpbrk);
480#endif
481
482#ifndef __HAVE_ARCH_STRSEP
483/**
484 * strsep - Split a string into tokens
485 * @s: The string to be searched
486 * @ct: The characters to search for
487 *
488 * strsep() updates @s to point after the token, ready for the next call.
489 *
490 * It returns empty tokens, too, behaving exactly like the libc function
491 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
492 * Same semantics, slimmer shape. ;)
493 */
494char *strsep(char **s, const char *ct)
495{
496 char *sbegin = *s;
497 char *end;
498
499 if (sbegin == NULL)
500 return NULL;
501
502 end = strpbrk(sbegin, ct);
503 if (end)
504 *end++ = '\0';
505 *s = end;
506 return sbegin;
507}
508EXPORT_SYMBOL(strsep);
509#endif
510
511/**
512 * sysfs_streq - return true if strings are equal, modulo trailing newline
513 * @s1: one string
514 * @s2: another string
515 *
516 * This routine returns true iff two strings are equal, treating both
517 * NUL and newline-then-NUL as equivalent string terminations. It's
518 * geared for use with sysfs input strings, which generally terminate
519 * with newlines but are compared against values without newlines.
520 */
521bool sysfs_streq(const char *s1, const char *s2)
522{
523 while (*s1 && *s1 == *s2) {
524 s1++;
525 s2++;
526 }
527
528 if (*s1 == *s2)
529 return true;
530 if (!*s1 && *s2 == '\n' && !s2[1])
531 return true;
532 if (*s1 == '\n' && !s1[1] && !*s2)
533 return true;
534 return false;
535}
536EXPORT_SYMBOL(sysfs_streq);
537
538/**
539 * strtobool - convert common user inputs into boolean values
540 * @s: input string
541 * @res: result
542 *
543 * This routine returns 0 iff the first character is one of 'Yy1Nn0'.
544 * Otherwise it will return -EINVAL. Value pointed to by res is
545 * updated upon finding a match.
546 */
547int strtobool(const char *s, bool *res)
548{
549 switch (s[0]) {
550 case 'y':
551 case 'Y':
552 case '1':
553 *res = true;
554 break;
555 case 'n':
556 case 'N':
557 case '0':
558 *res = false;
559 break;
560 default:
561 return -EINVAL;
562 }
563 return 0;
564}
565EXPORT_SYMBOL(strtobool);
566
567#ifndef __HAVE_ARCH_MEMSET
568/**
569 * memset - Fill a region of memory with the given value
570 * @s: Pointer to the start of the area.
571 * @c: The byte to fill the area with
572 * @count: The size of the area.
573 *
574 * Do not use memset() to access IO space, use memset_io() instead.
575 */
576void *memset(void *s, int c, size_t count)
577{
578 char *xs = s;
579
580 while (count--)
581 *xs++ = c;
582 return s;
583}
584EXPORT_SYMBOL(memset);
585#endif
586
587#ifndef __HAVE_ARCH_MEMCPY
588/**
589 * memcpy - Copy one area of memory to another
590 * @dest: Where to copy to
591 * @src: Where to copy from
592 * @count: The size of the area.
593 *
594 * You should not use this function to access IO space, use memcpy_toio()
595 * or memcpy_fromio() instead.
596 */
597void *memcpy(void *dest, const void *src, size_t count)
598{
599 char *tmp = dest;
600 const char *s = src;
601
602 while (count--)
603 *tmp++ = *s++;
604 return dest;
605}
606EXPORT_SYMBOL(memcpy);
607#endif
608
609#ifndef __HAVE_ARCH_MEMMOVE
610/**
611 * memmove - Copy one area of memory to another
612 * @dest: Where to copy to
613 * @src: Where to copy from
614 * @count: The size of the area.
615 *
616 * Unlike memcpy(), memmove() copes with overlapping areas.
617 */
618void *memmove(void *dest, const void *src, size_t count)
619{
620 char *tmp;
621 const char *s;
622
623 if (dest <= src) {
624 tmp = dest;
625 s = src;
626 while (count--)
627 *tmp++ = *s++;
628 } else {
629 tmp = dest;
630 tmp += count;
631 s = src;
632 s += count;
633 while (count--)
634 *--tmp = *--s;
635 }
636 return dest;
637}
638EXPORT_SYMBOL(memmove);
639#endif
640
641#ifndef __HAVE_ARCH_MEMCMP
642/**
643 * memcmp - Compare two areas of memory
644 * @cs: One area of memory
645 * @ct: Another area of memory
646 * @count: The size of the area.
647 */
648#undef memcmp
649int memcmp(const void *cs, const void *ct, size_t count)
650{
651 const unsigned char *su1, *su2;
652 int res = 0;
653
654 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
655 if ((res = *su1 - *su2) != 0)
656 break;
657 return res;
658}
659EXPORT_SYMBOL(memcmp);
660#endif
661
662#ifndef __HAVE_ARCH_MEMSCAN
663/**
664 * memscan - Find a character in an area of memory.
665 * @addr: The memory area
666 * @c: The byte to search for
667 * @size: The size of the area.
668 *
669 * returns the address of the first occurrence of @c, or 1 byte past
670 * the area if @c is not found
671 */
672void *memscan(void *addr, int c, size_t size)
673{
674 unsigned char *p = addr;
675
676 while (size) {
677 if (*p == c)
678 return (void *)p;
679 p++;
680 size--;
681 }
682 return (void *)p;
683}
684EXPORT_SYMBOL(memscan);
685#endif
686
687#ifndef __HAVE_ARCH_STRSTR
688/**
689 * strstr - Find the first substring in a %NUL terminated string
690 * @s1: The string to be searched
691 * @s2: The string to search for
692 */
693char *strstr(const char *s1, const char *s2)
694{
695 size_t l1, l2;
696
697 l2 = strlen(s2);
698 if (!l2)
699 return (char *)s1;
700 l1 = strlen(s1);
701 while (l1 >= l2) {
702 l1--;
703 if (!memcmp(s1, s2, l2))
704 return (char *)s1;
705 s1++;
706 }
707 return NULL;
708}
709EXPORT_SYMBOL(strstr);
710#endif
711
712#ifndef __HAVE_ARCH_STRNSTR
713/**
714 * strnstr - Find the first substring in a length-limited string
715 * @s1: The string to be searched
716 * @s2: The string to search for
717 * @len: the maximum number of characters to search
718 */
719char *strnstr(const char *s1, const char *s2, size_t len)
720{
721 size_t l2;
722
723 l2 = strlen(s2);
724 if (!l2)
725 return (char *)s1;
726 while (len >= l2) {
727 len--;
728 if (!memcmp(s1, s2, l2))
729 return (char *)s1;
730 s1++;
731 }
732 return NULL;
733}
734EXPORT_SYMBOL(strnstr);
735#endif
736
737#ifndef __HAVE_ARCH_MEMCHR
738/**
739 * memchr - Find a character in an area of memory.
740 * @s: The memory area
741 * @c: The byte to search for
742 * @n: The size of the area.
743 *
744 * returns the address of the first occurrence of @c, or %NULL
745 * if @c is not found
746 */
747void *memchr(const void *s, int c, size_t n)
748{
749 const unsigned char *p = s;
750 while (n-- != 0) {
751 if ((unsigned char)c == *p++) {
752 return (void *)(p - 1);
753 }
754 }
755 return NULL;
756}
757EXPORT_SYMBOL(memchr);
758#endif