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 */ 88#undef strcpy 89char *strcpy(char *dest, const char *src) 90{ 91 char *tmp = dest; 92 93 while ((*dest++ = *src++) != '\0') 94 /* nothing */; 95 return tmp; 96} 97EXPORT_SYMBOL(strcpy); 98#endif 99 100#ifndef __HAVE_ARCH_STRNCPY 101/** 102 * strncpy - Copy a length-limited, C-string 103 * @dest: Where to copy the string to 104 * @src: Where to copy the string from 105 * @count: The maximum number of bytes to copy 106 * 107 * The result is not %NUL-terminated if the source exceeds 108 * @count bytes. 109 * 110 * In the case where the length of @src is less than that of 111 * count, the remainder of @dest will be padded with %NUL. 112 * 113 */ 114char *strncpy(char *dest, const char *src, size_t count) 115{ 116 char *tmp = dest; 117 118 while (count) { 119 if ((*tmp = *src) != 0) 120 src++; 121 tmp++; 122 count--; 123 } 124 return dest; 125} 126EXPORT_SYMBOL(strncpy); 127#endif 128 129#ifndef __HAVE_ARCH_STRLCPY 130/** 131 * strlcpy - Copy a C-string into a sized buffer 132 * @dest: Where to copy the string to 133 * @src: Where to copy the string from 134 * @size: size of destination buffer 135 * 136 * Compatible with ``*BSD``: the result is always a valid 137 * NUL-terminated string that fits in the buffer (unless, 138 * of course, the buffer size is zero). It does not pad 139 * out the result like strncpy() does. 140 */ 141size_t strlcpy(char *dest, const char *src, size_t size) 142{ 143 size_t ret = strlen(src); 144 145 if (size) { 146 size_t len = (ret >= size) ? size - 1 : ret; 147 memcpy(dest, src, len); 148 dest[len] = '\0'; 149 } 150 return ret; 151} 152EXPORT_SYMBOL(strlcpy); 153#endif 154 155#ifndef __HAVE_ARCH_STRSCPY 156/** 157 * strscpy - Copy a C-string into a sized buffer 158 * @dest: Where to copy the string to 159 * @src: Where to copy the string from 160 * @count: Size of destination buffer 161 * 162 * Copy the string, or as much of it as fits, into the dest buffer. The 163 * behavior is undefined if the string buffers overlap. The destination 164 * 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 zeroing is desired please use strscpy_pad(). 175 * 176 * Returns: 177 * * The number of characters copied (not including the trailing %NUL) 178 * * -E2BIG if count is 0 or @src was truncated. 179 */ 180ssize_t strscpy(char *dest, const char *src, size_t count) 181{ 182 const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; 183 size_t max = count; 184 long res = 0; 185 186 if (count == 0 || WARN_ON_ONCE(count > INT_MAX)) 187 return -E2BIG; 188 189#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 190 /* 191 * If src is unaligned, don't cross a page boundary, 192 * since we don't know if the next page is mapped. 193 */ 194 if ((long)src & (sizeof(long) - 1)) { 195 size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1)); 196 if (limit < max) 197 max = limit; 198 } 199#else 200 /* If src or dest is unaligned, don't do word-at-a-time. */ 201 if (((long) dest | (long) src) & (sizeof(long) - 1)) 202 max = 0; 203#endif 204 205 while (max >= sizeof(unsigned long)) { 206 unsigned long c, data; 207 208 c = read_word_at_a_time(src+res); 209 if (has_zero(c, &data, &constants)) { 210 data = prep_zero_mask(c, data, &constants); 211 data = create_zero_mask(data); 212 *(unsigned long *)(dest+res) = c & zero_bytemask(data); 213 return res + find_zero(data); 214 } 215 *(unsigned long *)(dest+res) = c; 216 res += sizeof(unsigned long); 217 count -= sizeof(unsigned long); 218 max -= sizeof(unsigned long); 219 } 220 221 while (count) { 222 char c; 223 224 c = src[res]; 225 dest[res] = c; 226 if (!c) 227 return res; 228 res++; 229 count--; 230 } 231 232 /* Hit buffer length without finding a NUL; force NUL-termination. */ 233 if (res) 234 dest[res-1] = '\0'; 235 236 return -E2BIG; 237} 238EXPORT_SYMBOL(strscpy); 239#endif 240 241/** 242 * strscpy_pad() - Copy a C-string into a sized buffer 243 * @dest: Where to copy the string to 244 * @src: Where to copy the string from 245 * @count: Size of destination buffer 246 * 247 * Copy the string, or as much of it as fits, into the dest buffer. The 248 * behavior is undefined if the string buffers overlap. The destination 249 * buffer is always %NUL terminated, unless it's zero-sized. 250 * 251 * If the source string is shorter than the destination buffer, zeros 252 * the tail of the destination buffer. 253 * 254 * For full explanation of why you may want to consider using the 255 * 'strscpy' functions please see the function docstring for strscpy(). 256 * 257 * Returns: 258 * * The number of characters copied (not including the trailing %NUL) 259 * * -E2BIG if count is 0 or @src was truncated. 260 */ 261ssize_t strscpy_pad(char *dest, const char *src, size_t count) 262{ 263 ssize_t written; 264 265 written = strscpy(dest, src, count); 266 if (written < 0 || written == count - 1) 267 return written; 268 269 memset(dest + written + 1, 0, count - written - 1); 270 271 return written; 272} 273EXPORT_SYMBOL(strscpy_pad); 274 275/** 276 * stpcpy - copy a string from src to dest returning a pointer to the new end 277 * of dest, including src's %NUL-terminator. May overrun dest. 278 * @dest: pointer to end of string being copied into. Must be large enough 279 * to receive copy. 280 * @src: pointer to the beginning of string being copied from. Must not overlap 281 * dest. 282 * 283 * stpcpy differs from strcpy in a key way: the return value is a pointer 284 * to the new %NUL-terminating character in @dest. (For strcpy, the return 285 * value is a pointer to the start of @dest). This interface is considered 286 * unsafe as it doesn't perform bounds checking of the inputs. As such it's 287 * not recommended for usage. Instead, its definition is provided in case 288 * the compiler lowers other libcalls to stpcpy. 289 */ 290char *stpcpy(char *__restrict__ dest, const char *__restrict__ src); 291char *stpcpy(char *__restrict__ dest, const char *__restrict__ src) 292{ 293 while ((*dest++ = *src++) != '\0') 294 /* nothing */; 295 return --dest; 296} 297EXPORT_SYMBOL(stpcpy); 298 299#ifndef __HAVE_ARCH_STRCAT 300/** 301 * strcat - Append one %NUL-terminated string to another 302 * @dest: The string to be appended to 303 * @src: The string to append to it 304 */ 305#undef strcat 306char *strcat(char *dest, const char *src) 307{ 308 char *tmp = dest; 309 310 while (*dest) 311 dest++; 312 while ((*dest++ = *src++) != '\0') 313 ; 314 return tmp; 315} 316EXPORT_SYMBOL(strcat); 317#endif 318 319#ifndef __HAVE_ARCH_STRNCAT 320/** 321 * strncat - Append a length-limited, C-string to another 322 * @dest: The string to be appended to 323 * @src: The string to append to it 324 * @count: The maximum numbers of bytes to copy 325 * 326 * Note that in contrast to strncpy(), strncat() ensures the result is 327 * terminated. 328 */ 329char *strncat(char *dest, const char *src, size_t count) 330{ 331 char *tmp = dest; 332 333 if (count) { 334 while (*dest) 335 dest++; 336 while ((*dest++ = *src++) != 0) { 337 if (--count == 0) { 338 *dest = '\0'; 339 break; 340 } 341 } 342 } 343 return tmp; 344} 345EXPORT_SYMBOL(strncat); 346#endif 347 348#ifndef __HAVE_ARCH_STRLCAT 349/** 350 * strlcat - Append a length-limited, C-string to another 351 * @dest: The string to be appended to 352 * @src: The string to append to it 353 * @count: The size of the destination buffer. 354 */ 355size_t strlcat(char *dest, const char *src, size_t count) 356{ 357 size_t dsize = strlen(dest); 358 size_t len = strlen(src); 359 size_t res = dsize + len; 360 361 /* This would be a bug */ 362 BUG_ON(dsize >= count); 363 364 dest += dsize; 365 count -= dsize; 366 if (len >= count) 367 len = count-1; 368 memcpy(dest, src, len); 369 dest[len] = 0; 370 return res; 371} 372EXPORT_SYMBOL(strlcat); 373#endif 374 375#ifndef __HAVE_ARCH_STRCMP 376/** 377 * strcmp - Compare two strings 378 * @cs: One string 379 * @ct: Another string 380 */ 381#undef strcmp 382int strcmp(const char *cs, const char *ct) 383{ 384 unsigned char c1, c2; 385 386 while (1) { 387 c1 = *cs++; 388 c2 = *ct++; 389 if (c1 != c2) 390 return c1 < c2 ? -1 : 1; 391 if (!c1) 392 break; 393 } 394 return 0; 395} 396EXPORT_SYMBOL(strcmp); 397#endif 398 399#ifndef __HAVE_ARCH_STRNCMP 400/** 401 * strncmp - Compare two length-limited strings 402 * @cs: One string 403 * @ct: Another string 404 * @count: The maximum number of bytes to compare 405 */ 406int strncmp(const char *cs, const char *ct, size_t count) 407{ 408 unsigned char c1, c2; 409 410 while (count) { 411 c1 = *cs++; 412 c2 = *ct++; 413 if (c1 != c2) 414 return c1 < c2 ? -1 : 1; 415 if (!c1) 416 break; 417 count--; 418 } 419 return 0; 420} 421EXPORT_SYMBOL(strncmp); 422#endif 423 424#ifndef __HAVE_ARCH_STRCHR 425/** 426 * strchr - Find the first occurrence of a character in a string 427 * @s: The string to be searched 428 * @c: The character to search for 429 * 430 * Note that the %NUL-terminator is considered part of the string, and can 431 * be searched for. 432 */ 433char *strchr(const char *s, int c) 434{ 435 for (; *s != (char)c; ++s) 436 if (*s == '\0') 437 return NULL; 438 return (char *)s; 439} 440EXPORT_SYMBOL(strchr); 441#endif 442 443#ifndef __HAVE_ARCH_STRCHRNUL 444/** 445 * strchrnul - Find and return a character in a string, or end of string 446 * @s: The string to be searched 447 * @c: The character to search for 448 * 449 * Returns pointer to first occurrence of 'c' in s. If c is not found, then 450 * return a pointer to the null byte at the end of s. 451 */ 452char *strchrnul(const char *s, int c) 453{ 454 while (*s && *s != (char)c) 455 s++; 456 return (char *)s; 457} 458EXPORT_SYMBOL(strchrnul); 459#endif 460 461/** 462 * strnchrnul - Find and return a character in a length limited string, 463 * or end of string 464 * @s: The string to be searched 465 * @count: The number of characters to be searched 466 * @c: The character to search for 467 * 468 * Returns pointer to the first occurrence of 'c' in s. If c is not found, 469 * then return a pointer to the last character of the string. 470 */ 471char *strnchrnul(const char *s, size_t count, int c) 472{ 473 while (count-- && *s && *s != (char)c) 474 s++; 475 return (char *)s; 476} 477 478#ifndef __HAVE_ARCH_STRRCHR 479/** 480 * strrchr - Find the last occurrence of a character in a string 481 * @s: The string to be searched 482 * @c: The character to search for 483 */ 484char *strrchr(const char *s, int c) 485{ 486 const char *last = NULL; 487 do { 488 if (*s == (char)c) 489 last = s; 490 } while (*s++); 491 return (char *)last; 492} 493EXPORT_SYMBOL(strrchr); 494#endif 495 496#ifndef __HAVE_ARCH_STRNCHR 497/** 498 * strnchr - Find a character in a length limited string 499 * @s: The string to be searched 500 * @count: The number of characters to be searched 501 * @c: The character to search for 502 * 503 * Note that the %NUL-terminator is considered part of the string, and can 504 * be searched for. 505 */ 506char *strnchr(const char *s, size_t count, int c) 507{ 508 while (count--) { 509 if (*s == (char)c) 510 return (char *)s; 511 if (*s++ == '\0') 512 break; 513 } 514 return NULL; 515} 516EXPORT_SYMBOL(strnchr); 517#endif 518 519/** 520 * skip_spaces - Removes leading whitespace from @str. 521 * @str: The string to be stripped. 522 * 523 * Returns a pointer to the first non-whitespace character in @str. 524 */ 525char *skip_spaces(const char *str) 526{ 527 while (isspace(*str)) 528 ++str; 529 return (char *)str; 530} 531EXPORT_SYMBOL(skip_spaces); 532 533/** 534 * strim - Removes leading and trailing whitespace from @s. 535 * @s: The string to be stripped. 536 * 537 * Note that the first trailing whitespace is replaced with a %NUL-terminator 538 * in the given string @s. Returns a pointer to the first non-whitespace 539 * character in @s. 540 */ 541char *strim(char *s) 542{ 543 size_t size; 544 char *end; 545 546 size = strlen(s); 547 if (!size) 548 return s; 549 550 end = s + size - 1; 551 while (end >= s && isspace(*end)) 552 end--; 553 *(end + 1) = '\0'; 554 555 return skip_spaces(s); 556} 557EXPORT_SYMBOL(strim); 558 559#ifndef __HAVE_ARCH_STRLEN 560/** 561 * strlen - Find the length of a string 562 * @s: The string to be sized 563 */ 564size_t strlen(const char *s) 565{ 566 const char *sc; 567 568 for (sc = s; *sc != '\0'; ++sc) 569 /* nothing */; 570 return sc - s; 571} 572EXPORT_SYMBOL(strlen); 573#endif 574 575#ifndef __HAVE_ARCH_STRNLEN 576/** 577 * strnlen - Find the length of a length-limited string 578 * @s: The string to be sized 579 * @count: The maximum number of bytes to search 580 */ 581size_t strnlen(const char *s, size_t count) 582{ 583 const char *sc; 584 585 for (sc = s; count-- && *sc != '\0'; ++sc) 586 /* nothing */; 587 return sc - s; 588} 589EXPORT_SYMBOL(strnlen); 590#endif 591 592#ifndef __HAVE_ARCH_STRSPN 593/** 594 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept 595 * @s: The string to be searched 596 * @accept: The string to search for 597 */ 598size_t strspn(const char *s, const char *accept) 599{ 600 const char *p; 601 const char *a; 602 size_t count = 0; 603 604 for (p = s; *p != '\0'; ++p) { 605 for (a = accept; *a != '\0'; ++a) { 606 if (*p == *a) 607 break; 608 } 609 if (*a == '\0') 610 return count; 611 ++count; 612 } 613 return count; 614} 615 616EXPORT_SYMBOL(strspn); 617#endif 618 619#ifndef __HAVE_ARCH_STRCSPN 620/** 621 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject 622 * @s: The string to be searched 623 * @reject: The string to avoid 624 */ 625size_t strcspn(const char *s, const char *reject) 626{ 627 const char *p; 628 const char *r; 629 size_t count = 0; 630 631 for (p = s; *p != '\0'; ++p) { 632 for (r = reject; *r != '\0'; ++r) { 633 if (*p == *r) 634 return count; 635 } 636 ++count; 637 } 638 return count; 639} 640EXPORT_SYMBOL(strcspn); 641#endif 642 643#ifndef __HAVE_ARCH_STRPBRK 644/** 645 * strpbrk - Find the first occurrence of a set of characters 646 * @cs: The string to be searched 647 * @ct: The characters to search for 648 */ 649char *strpbrk(const char *cs, const char *ct) 650{ 651 const char *sc1, *sc2; 652 653 for (sc1 = cs; *sc1 != '\0'; ++sc1) { 654 for (sc2 = ct; *sc2 != '\0'; ++sc2) { 655 if (*sc1 == *sc2) 656 return (char *)sc1; 657 } 658 } 659 return NULL; 660} 661EXPORT_SYMBOL(strpbrk); 662#endif 663 664#ifndef __HAVE_ARCH_STRSEP 665/** 666 * strsep - Split a string into tokens 667 * @s: The string to be searched 668 * @ct: The characters to search for 669 * 670 * strsep() updates @s to point after the token, ready for the next call. 671 * 672 * It returns empty tokens, too, behaving exactly like the libc function 673 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. 674 * Same semantics, slimmer shape. ;) 675 */ 676char *strsep(char **s, const char *ct) 677{ 678 char *sbegin = *s; 679 char *end; 680 681 if (sbegin == NULL) 682 return NULL; 683 684 end = strpbrk(sbegin, ct); 685 if (end) 686 *end++ = '\0'; 687 *s = end; 688 return sbegin; 689} 690EXPORT_SYMBOL(strsep); 691#endif 692 693/** 694 * sysfs_streq - return true if strings are equal, modulo trailing newline 695 * @s1: one string 696 * @s2: another string 697 * 698 * This routine returns true iff two strings are equal, treating both 699 * NUL and newline-then-NUL as equivalent string terminations. It's 700 * geared for use with sysfs input strings, which generally terminate 701 * with newlines but are compared against values without newlines. 702 */ 703bool sysfs_streq(const char *s1, const char *s2) 704{ 705 while (*s1 && *s1 == *s2) { 706 s1++; 707 s2++; 708 } 709 710 if (*s1 == *s2) 711 return true; 712 if (!*s1 && *s2 == '\n' && !s2[1]) 713 return true; 714 if (*s1 == '\n' && !s1[1] && !*s2) 715 return true; 716 return false; 717} 718EXPORT_SYMBOL(sysfs_streq); 719 720/** 721 * match_string - matches given string in an array 722 * @array: array of strings 723 * @n: number of strings in the array or -1 for NULL terminated arrays 724 * @string: string to match with 725 * 726 * This routine will look for a string in an array of strings up to the 727 * n-th element in the array or until the first NULL element. 728 * 729 * Historically the value of -1 for @n, was used to search in arrays that 730 * are NULL terminated. However, the function does not make a distinction 731 * when finishing the search: either @n elements have been compared OR 732 * the first NULL element was found. 733 * 734 * Return: 735 * index of a @string in the @array if matches, or %-EINVAL otherwise. 736 */ 737int match_string(const char * const *array, size_t n, const char *string) 738{ 739 int index; 740 const char *item; 741 742 for (index = 0; index < n; index++) { 743 item = array[index]; 744 if (!item) 745 break; 746 if (!strcmp(item, string)) 747 return index; 748 } 749 750 return -EINVAL; 751} 752EXPORT_SYMBOL(match_string); 753 754/** 755 * __sysfs_match_string - matches given string in an array 756 * @array: array of strings 757 * @n: number of strings in the array or -1 for NULL terminated arrays 758 * @str: string to match with 759 * 760 * Returns index of @str in the @array or -EINVAL, just like match_string(). 761 * Uses sysfs_streq instead of strcmp for matching. 762 * 763 * This routine will look for a string in an array of strings up to the 764 * n-th element in the array or until the first NULL element. 765 * 766 * Historically the value of -1 for @n, was used to search in arrays that 767 * are NULL terminated. However, the function does not make a distinction 768 * when finishing the search: either @n elements have been compared OR 769 * the first NULL element was found. 770 */ 771int __sysfs_match_string(const char * const *array, size_t n, const char *str) 772{ 773 const char *item; 774 int index; 775 776 for (index = 0; index < n; index++) { 777 item = array[index]; 778 if (!item) 779 break; 780 if (sysfs_streq(item, str)) 781 return index; 782 } 783 784 return -EINVAL; 785} 786EXPORT_SYMBOL(__sysfs_match_string); 787 788#ifndef __HAVE_ARCH_MEMSET 789/** 790 * memset - Fill a region of memory with the given value 791 * @s: Pointer to the start of the area. 792 * @c: The byte to fill the area with 793 * @count: The size of the area. 794 * 795 * Do not use memset() to access IO space, use memset_io() instead. 796 */ 797void *memset(void *s, int c, size_t count) 798{ 799 char *xs = s; 800 801 while (count--) 802 *xs++ = c; 803 return s; 804} 805EXPORT_SYMBOL(memset); 806#endif 807 808#ifndef __HAVE_ARCH_MEMSET16 809/** 810 * memset16() - Fill a memory area with a uint16_t 811 * @s: Pointer to the start of the area. 812 * @v: The value to fill the area with 813 * @count: The number of values to store 814 * 815 * Differs from memset() in that it fills with a uint16_t instead 816 * of a byte. Remember that @count is the number of uint16_ts to 817 * store, not the number of bytes. 818 */ 819void *memset16(uint16_t *s, uint16_t v, size_t count) 820{ 821 uint16_t *xs = s; 822 823 while (count--) 824 *xs++ = v; 825 return s; 826} 827EXPORT_SYMBOL(memset16); 828#endif 829 830#ifndef __HAVE_ARCH_MEMSET32 831/** 832 * memset32() - Fill a memory area with a uint32_t 833 * @s: Pointer to the start of the area. 834 * @v: The value to fill the area with 835 * @count: The number of values to store 836 * 837 * Differs from memset() in that it fills with a uint32_t instead 838 * of a byte. Remember that @count is the number of uint32_ts to 839 * store, not the number of bytes. 840 */ 841void *memset32(uint32_t *s, uint32_t v, size_t count) 842{ 843 uint32_t *xs = s; 844 845 while (count--) 846 *xs++ = v; 847 return s; 848} 849EXPORT_SYMBOL(memset32); 850#endif 851 852#ifndef __HAVE_ARCH_MEMSET64 853/** 854 * memset64() - Fill a memory area with a uint64_t 855 * @s: Pointer to the start of the area. 856 * @v: The value to fill the area with 857 * @count: The number of values to store 858 * 859 * Differs from memset() in that it fills with a uint64_t instead 860 * of a byte. Remember that @count is the number of uint64_ts to 861 * store, not the number of bytes. 862 */ 863void *memset64(uint64_t *s, uint64_t v, size_t count) 864{ 865 uint64_t *xs = s; 866 867 while (count--) 868 *xs++ = v; 869 return s; 870} 871EXPORT_SYMBOL(memset64); 872#endif 873 874#ifndef __HAVE_ARCH_MEMCPY 875/** 876 * memcpy - Copy one area of memory to another 877 * @dest: Where to copy to 878 * @src: Where to copy from 879 * @count: The size of the area. 880 * 881 * You should not use this function to access IO space, use memcpy_toio() 882 * or memcpy_fromio() instead. 883 */ 884void *memcpy(void *dest, const void *src, size_t count) 885{ 886 char *tmp = dest; 887 const char *s = src; 888 889 while (count--) 890 *tmp++ = *s++; 891 return dest; 892} 893EXPORT_SYMBOL(memcpy); 894#endif 895 896#ifndef __HAVE_ARCH_MEMMOVE 897/** 898 * memmove - Copy one area of memory to another 899 * @dest: Where to copy to 900 * @src: Where to copy from 901 * @count: The size of the area. 902 * 903 * Unlike memcpy(), memmove() copes with overlapping areas. 904 */ 905void *memmove(void *dest, const void *src, size_t count) 906{ 907 char *tmp; 908 const char *s; 909 910 if (dest <= src) { 911 tmp = dest; 912 s = src; 913 while (count--) 914 *tmp++ = *s++; 915 } else { 916 tmp = dest; 917 tmp += count; 918 s = src; 919 s += count; 920 while (count--) 921 *--tmp = *--s; 922 } 923 return dest; 924} 925EXPORT_SYMBOL(memmove); 926#endif 927 928#ifndef __HAVE_ARCH_MEMCMP 929/** 930 * memcmp - Compare two areas of memory 931 * @cs: One area of memory 932 * @ct: Another area of memory 933 * @count: The size of the area. 934 */ 935#undef memcmp 936__visible int memcmp(const void *cs, const void *ct, size_t count) 937{ 938 const unsigned char *su1, *su2; 939 int res = 0; 940 941 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) 942 if ((res = *su1 - *su2) != 0) 943 break; 944 return res; 945} 946EXPORT_SYMBOL(memcmp); 947#endif 948 949#ifndef __HAVE_ARCH_BCMP 950/** 951 * bcmp - returns 0 if and only if the buffers have identical contents. 952 * @a: pointer to first buffer. 953 * @b: pointer to second buffer. 954 * @len: size of buffers. 955 * 956 * The sign or magnitude of a non-zero return value has no particular 957 * meaning, and architectures may implement their own more efficient bcmp(). So 958 * while this particular implementation is a simple (tail) call to memcmp, do 959 * not rely on anything but whether the return value is zero or non-zero. 960 */ 961#undef bcmp 962int bcmp(const void *a, const void *b, size_t len) 963{ 964 return memcmp(a, b, len); 965} 966EXPORT_SYMBOL(bcmp); 967#endif 968 969#ifndef __HAVE_ARCH_MEMSCAN 970/** 971 * memscan - Find a character in an area of memory. 972 * @addr: The memory area 973 * @c: The byte to search for 974 * @size: The size of the area. 975 * 976 * returns the address of the first occurrence of @c, or 1 byte past 977 * the area if @c is not found 978 */ 979void *memscan(void *addr, int c, size_t size) 980{ 981 unsigned char *p = addr; 982 983 while (size) { 984 if (*p == c) 985 return (void *)p; 986 p++; 987 size--; 988 } 989 return (void *)p; 990} 991EXPORT_SYMBOL(memscan); 992#endif 993 994#ifndef __HAVE_ARCH_STRSTR 995/** 996 * strstr - Find the first substring in a %NUL terminated string 997 * @s1: The string to be searched 998 * @s2: The string to search for 999 */ 1000char *strstr(const char *s1, const char *s2) 1001{ 1002 size_t l1, l2; 1003 1004 l2 = strlen(s2); 1005 if (!l2) 1006 return (char *)s1; 1007 l1 = strlen(s1); 1008 while (l1 >= l2) { 1009 l1--; 1010 if (!memcmp(s1, s2, l2)) 1011 return (char *)s1; 1012 s1++; 1013 } 1014 return NULL; 1015} 1016EXPORT_SYMBOL(strstr); 1017#endif 1018 1019#ifndef __HAVE_ARCH_STRNSTR 1020/** 1021 * strnstr - Find the first substring in a length-limited string 1022 * @s1: The string to be searched 1023 * @s2: The string to search for 1024 * @len: the maximum number of characters to search 1025 */ 1026char *strnstr(const char *s1, const char *s2, size_t len) 1027{ 1028 size_t l2; 1029 1030 l2 = strlen(s2); 1031 if (!l2) 1032 return (char *)s1; 1033 while (len >= l2) { 1034 len--; 1035 if (!memcmp(s1, s2, l2)) 1036 return (char *)s1; 1037 s1++; 1038 } 1039 return NULL; 1040} 1041EXPORT_SYMBOL(strnstr); 1042#endif 1043 1044#ifndef __HAVE_ARCH_MEMCHR 1045/** 1046 * memchr - Find a character in an area of memory. 1047 * @s: The memory area 1048 * @c: The byte to search for 1049 * @n: The size of the area. 1050 * 1051 * returns the address of the first occurrence of @c, or %NULL 1052 * if @c is not found 1053 */ 1054void *memchr(const void *s, int c, size_t n) 1055{ 1056 const unsigned char *p = s; 1057 while (n-- != 0) { 1058 if ((unsigned char)c == *p++) { 1059 return (void *)(p - 1); 1060 } 1061 } 1062 return NULL; 1063} 1064EXPORT_SYMBOL(memchr); 1065#endif 1066 1067static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) 1068{ 1069 while (bytes) { 1070 if (*start != value) 1071 return (void *)start; 1072 start++; 1073 bytes--; 1074 } 1075 return NULL; 1076} 1077 1078/** 1079 * memchr_inv - Find an unmatching character in an area of memory. 1080 * @start: The memory area 1081 * @c: Find a character other than c 1082 * @bytes: The size of the area. 1083 * 1084 * returns the address of the first character other than @c, or %NULL 1085 * if the whole buffer contains just @c. 1086 */ 1087void *memchr_inv(const void *start, int c, size_t bytes) 1088{ 1089 u8 value = c; 1090 u64 value64; 1091 unsigned int words, prefix; 1092 1093 if (bytes <= 16) 1094 return check_bytes8(start, value, bytes); 1095 1096 value64 = value; 1097#if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 1098 value64 *= 0x0101010101010101ULL; 1099#elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) 1100 value64 *= 0x01010101; 1101 value64 |= value64 << 32; 1102#else 1103 value64 |= value64 << 8; 1104 value64 |= value64 << 16; 1105 value64 |= value64 << 32; 1106#endif 1107 1108 prefix = (unsigned long)start % 8; 1109 if (prefix) { 1110 u8 *r; 1111 1112 prefix = 8 - prefix; 1113 r = check_bytes8(start, value, prefix); 1114 if (r) 1115 return r; 1116 start += prefix; 1117 bytes -= prefix; 1118 } 1119 1120 words = bytes / 8; 1121 1122 while (words) { 1123 if (*(u64 *)start != value64) 1124 return check_bytes8(start, value, 8); 1125 start += 8; 1126 words--; 1127 } 1128 1129 return check_bytes8(start, value, bytes % 8); 1130} 1131EXPORT_SYMBOL(memchr_inv); 1132 1133/** 1134 * strreplace - Replace all occurrences of character in string. 1135 * @s: The string to operate on. 1136 * @old: The character being replaced. 1137 * @new: The character @old is replaced with. 1138 * 1139 * Returns pointer to the nul byte at the end of @s. 1140 */ 1141char *strreplace(char *s, char old, char new) 1142{ 1143 for (; *s; ++s) 1144 if (*s == old) 1145 *s = new; 1146 return s; 1147} 1148EXPORT_SYMBOL(strreplace); 1149 1150void fortify_panic(const char *name) 1151{ 1152 pr_emerg("detected buffer overflow in %s\n", name); 1153 BUG(); 1154} 1155EXPORT_SYMBOL(fortify_panic); 1156