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Diffstat (limited to 'lib/string.c')
| -rw-r--r-- | lib/string.c | 1131 |
1 files changed, 1131 insertions, 0 deletions
diff --git a/lib/string.c b/lib/string.c new file mode 100644 index 000000000..f7f777044 --- /dev/null +++ b/lib/string.c @@ -0,0 +1,1131 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/lib/string.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +/* + * stupid library routines.. The optimized versions should generally be found + * as inline code in <asm-xx/string.h> + * + * These are buggy as well.. + * + * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de> + * - Added strsep() which will replace strtok() soon (because strsep() is + * reentrant and should be faster). Use only strsep() in new code, please. + * + * * Sat Feb 09 2002, Jason Thomas <jason@topic.com.au>, + * Matthew Hawkins <matt@mh.dropbear.id.au> + * - Kissed strtok() goodbye + */ + +#include <linux/types.h> +#include <linux/string.h> +#include <linux/ctype.h> +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/bug.h> +#include <linux/errno.h> + +#include <asm/byteorder.h> +#include <asm/word-at-a-time.h> +#include <asm/page.h> + +#ifndef __HAVE_ARCH_STRNCASECMP +/** + * strncasecmp - Case insensitive, length-limited string comparison + * @s1: One string + * @s2: The other string + * @len: the maximum number of characters to compare + */ +int strncasecmp(const char *s1, const char *s2, size_t len) +{ + /* Yes, Virginia, it had better be unsigned */ + unsigned char c1, c2; + + if (!len) + return 0; + + do { + c1 = *s1++; + c2 = *s2++; + if (!c1 || !c2) + break; + if (c1 == c2) + continue; + c1 = tolower(c1); + c2 = tolower(c2); + if (c1 != c2) + break; + } while (--len); + return (int)c1 - (int)c2; +} +EXPORT_SYMBOL(strncasecmp); +#endif + +#ifndef __HAVE_ARCH_STRCASECMP +int strcasecmp(const char *s1, const char *s2) +{ + int c1, c2; + + do { + c1 = tolower(*s1++); + c2 = tolower(*s2++); + } while (c1 == c2 && c1 != 0); + return c1 - c2; +} +EXPORT_SYMBOL(strcasecmp); +#endif + +#ifndef __HAVE_ARCH_STRCPY +/** + * strcpy - Copy a %NUL terminated string + * @dest: Where to copy the string to + * @src: Where to copy the string from + */ +#undef strcpy +char *strcpy(char *dest, const char *src) +{ + char *tmp = dest; + + while ((*dest++ = *src++) != '\0') + /* nothing */; + return tmp; +} +EXPORT_SYMBOL(strcpy); +#endif + +#ifndef __HAVE_ARCH_STRNCPY +/** + * strncpy - Copy a length-limited, C-string + * @dest: Where to copy the string to + * @src: Where to copy the string from + * @count: The maximum number of bytes to copy + * + * The result is not %NUL-terminated if the source exceeds + * @count bytes. + * + * In the case where the length of @src is less than that of + * count, the remainder of @dest will be padded with %NUL. + * + */ +char *strncpy(char *dest, const char *src, size_t count) +{ + char *tmp = dest; + + while (count) { + if ((*tmp = *src) != 0) + src++; + tmp++; + count--; + } + return dest; +} +EXPORT_SYMBOL(strncpy); +#endif + +#ifndef __HAVE_ARCH_STRLCPY +/** + * strlcpy - Copy a C-string into a sized buffer + * @dest: Where to copy the string to + * @src: Where to copy the string from + * @size: size of destination buffer + * + * Compatible with ``*BSD``: the result is always a valid + * NUL-terminated string that fits in the buffer (unless, + * of course, the buffer size is zero). It does not pad + * out the result like strncpy() does. + */ +size_t strlcpy(char *dest, const char *src, size_t size) +{ + size_t ret = strlen(src); + + if (size) { + size_t len = (ret >= size) ? size - 1 : ret; + memcpy(dest, src, len); + dest[len] = '\0'; + } + return ret; +} +EXPORT_SYMBOL(strlcpy); +#endif + +#ifndef __HAVE_ARCH_STRSCPY +/** + * strscpy - Copy a C-string into a sized buffer + * @dest: Where to copy the string to + * @src: Where to copy the string from + * @count: Size of destination buffer + * + * Copy the string, or as much of it as fits, into the dest buffer. The + * behavior is undefined if the string buffers overlap. The destination + * buffer is always NUL terminated, unless it's zero-sized. + * + * Preferred to strlcpy() since the API doesn't require reading memory + * from the src string beyond the specified "count" bytes, and since + * the return value is easier to error-check than strlcpy()'s. + * In addition, the implementation is robust to the string changing out + * from underneath it, unlike the current strlcpy() implementation. + * + * Preferred to strncpy() since it always returns a valid string, and + * doesn't unnecessarily force the tail of the destination buffer to be + * zeroed. If zeroing is desired please use strscpy_pad(). + * + * Return: The number of characters copied (not including the trailing + * %NUL) or -E2BIG if the destination buffer wasn't big enough. + */ +ssize_t strscpy(char *dest, const char *src, size_t count) +{ + const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; + size_t max = count; + long res = 0; + + if (count == 0) + return -E2BIG; + +#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + /* + * If src is unaligned, don't cross a page boundary, + * since we don't know if the next page is mapped. + */ + if ((long)src & (sizeof(long) - 1)) { + size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1)); + if (limit < max) + max = limit; + } +#else + /* If src or dest is unaligned, don't do word-at-a-time. */ + if (((long) dest | (long) src) & (sizeof(long) - 1)) + max = 0; +#endif + + while (max >= sizeof(unsigned long)) { + unsigned long c, data; + + c = read_word_at_a_time(src+res); + if (has_zero(c, &data, &constants)) { + data = prep_zero_mask(c, data, &constants); + data = create_zero_mask(data); + *(unsigned long *)(dest+res) = c & zero_bytemask(data); + return res + find_zero(data); + } + *(unsigned long *)(dest+res) = c; + res += sizeof(unsigned long); + count -= sizeof(unsigned long); + max -= sizeof(unsigned long); + } + + while (count) { + char c; + + c = src[res]; + dest[res] = c; + if (!c) + return res; + res++; + count--; + } + + /* Hit buffer length without finding a NUL; force NUL-termination. */ + if (res) + dest[res-1] = '\0'; + + return -E2BIG; +} +EXPORT_SYMBOL(strscpy); +#endif + +/** + * stpcpy - copy a string from src to dest returning a pointer to the new end + * of dest, including src's %NUL-terminator. May overrun dest. + * @dest: pointer to end of string being copied into. Must be large enough + * to receive copy. + * @src: pointer to the beginning of string being copied from. Must not overlap + * dest. + * + * stpcpy differs from strcpy in a key way: the return value is a pointer + * to the new %NUL-terminating character in @dest. (For strcpy, the return + * value is a pointer to the start of @dest). This interface is considered + * unsafe as it doesn't perform bounds checking of the inputs. As such it's + * not recommended for usage. Instead, its definition is provided in case + * the compiler lowers other libcalls to stpcpy. + */ +char *stpcpy(char *__restrict__ dest, const char *__restrict__ src); +char *stpcpy(char *__restrict__ dest, const char *__restrict__ src) +{ + while ((*dest++ = *src++) != '\0') + /* nothing */; + return --dest; +} +EXPORT_SYMBOL(stpcpy); + +/** + * strscpy_pad() - Copy a C-string into a sized buffer + * @dest: Where to copy the string to + * @src: Where to copy the string from + * @count: Size of destination buffer + * + * Copy the string, or as much of it as fits, into the dest buffer. The + * behavior is undefined if the string buffers overlap. The destination + * buffer is always %NUL terminated, unless it's zero-sized. + * + * If the source string is shorter than the destination buffer, zeros + * the tail of the destination buffer. + * + * For full explanation of why you may want to consider using the + * 'strscpy' functions please see the function docstring for strscpy(). + * + * Return: The number of characters copied (not including the trailing + * %NUL) or -E2BIG if the destination buffer wasn't big enough. + */ +ssize_t strscpy_pad(char *dest, const char *src, size_t count) +{ + ssize_t written; + + written = strscpy(dest, src, count); + if (written < 0 || written == count - 1) + return written; + + memset(dest + written + 1, 0, count - written - 1); + + return written; +} +EXPORT_SYMBOL(strscpy_pad); + +#ifndef __HAVE_ARCH_STRCAT +/** + * strcat - Append one %NUL-terminated string to another + * @dest: The string to be appended to + * @src: The string to append to it + */ +#undef strcat +char *strcat(char *dest, const char *src) +{ + char *tmp = dest; + + while (*dest) + dest++; + while ((*dest++ = *src++) != '\0') + ; + return tmp; +} +EXPORT_SYMBOL(strcat); +#endif + +#ifndef __HAVE_ARCH_STRNCAT +/** + * strncat - Append a length-limited, C-string to another + * @dest: The string to be appended to + * @src: The string to append to it + * @count: The maximum numbers of bytes to copy + * + * Note that in contrast to strncpy(), strncat() ensures the result is + * terminated. + */ +char *strncat(char *dest, const char *src, size_t count) +{ + char *tmp = dest; + + if (count) { + while (*dest) + dest++; + while ((*dest++ = *src++) != 0) { + if (--count == 0) { + *dest = '\0'; + break; + } + } + } + return tmp; +} +EXPORT_SYMBOL(strncat); +#endif + +#ifndef __HAVE_ARCH_STRLCAT +/** + * strlcat - Append a length-limited, C-string to another + * @dest: The string to be appended to + * @src: The string to append to it + * @count: The size of the destination buffer. + */ +size_t strlcat(char *dest, const char *src, size_t count) +{ + size_t dsize = strlen(dest); + size_t len = strlen(src); + size_t res = dsize + len; + + /* This would be a bug */ + BUG_ON(dsize >= count); + + dest += dsize; + count -= dsize; + if (len >= count) + len = count-1; + memcpy(dest, src, len); + dest[len] = 0; + return res; +} +EXPORT_SYMBOL(strlcat); +#endif + +#ifndef __HAVE_ARCH_STRCMP +/** + * strcmp - Compare two strings + * @cs: One string + * @ct: Another string + */ +#undef strcmp +int strcmp(const char *cs, const char *ct) +{ + unsigned char c1, c2; + + while (1) { + c1 = *cs++; + c2 = *ct++; + if (c1 != c2) + return c1 < c2 ? -1 : 1; + if (!c1) + break; + } + return 0; +} +EXPORT_SYMBOL(strcmp); +#endif + +#ifndef __HAVE_ARCH_STRNCMP +/** + * strncmp - Compare two length-limited strings + * @cs: One string + * @ct: Another string + * @count: The maximum number of bytes to compare + */ +int strncmp(const char *cs, const char *ct, size_t count) +{ + unsigned char c1, c2; + + while (count) { + c1 = *cs++; + c2 = *ct++; + if (c1 != c2) + return c1 < c2 ? -1 : 1; + if (!c1) + break; + count--; + } + return 0; +} +EXPORT_SYMBOL(strncmp); +#endif + +#ifndef __HAVE_ARCH_STRCHR +/** + * strchr - Find the first occurrence of a character in a string + * @s: The string to be searched + * @c: The character to search for + */ +char *strchr(const char *s, int c) +{ + for (; *s != (char)c; ++s) + if (*s == '\0') + return NULL; + return (char *)s; +} +EXPORT_SYMBOL(strchr); +#endif + +#ifndef __HAVE_ARCH_STRCHRNUL +/** + * strchrnul - Find and return a character in a string, or end of string + * @s: The string to be searched + * @c: The character to search for + * + * Returns pointer to first occurrence of 'c' in s. If c is not found, then + * return a pointer to the null byte at the end of s. + */ +char *strchrnul(const char *s, int c) +{ + while (*s && *s != (char)c) + s++; + return (char *)s; +} +EXPORT_SYMBOL(strchrnul); +#endif + +#ifndef __HAVE_ARCH_STRRCHR +/** + * strrchr - Find the last occurrence of a character in a string + * @s: The string to be searched + * @c: The character to search for + */ +char *strrchr(const char *s, int c) +{ + const char *last = NULL; + do { + if (*s == (char)c) + last = s; + } while (*s++); + return (char *)last; +} +EXPORT_SYMBOL(strrchr); +#endif + +#ifndef __HAVE_ARCH_STRNCHR +/** + * strnchr - Find a character in a length limited string + * @s: The string to be searched + * @count: The number of characters to be searched + * @c: The character to search for + */ +char *strnchr(const char *s, size_t count, int c) +{ + for (; count-- && *s != '\0'; ++s) + if (*s == (char)c) + return (char *)s; + return NULL; +} +EXPORT_SYMBOL(strnchr); +#endif + +/** + * skip_spaces - Removes leading whitespace from @str. + * @str: The string to be stripped. + * + * Returns a pointer to the first non-whitespace character in @str. + */ +char *skip_spaces(const char *str) +{ + while (isspace(*str)) + ++str; + return (char *)str; +} +EXPORT_SYMBOL(skip_spaces); + +/** + * strim - Removes leading and trailing whitespace from @s. + * @s: The string to be stripped. + * + * Note that the first trailing whitespace is replaced with a %NUL-terminator + * in the given string @s. Returns a pointer to the first non-whitespace + * character in @s. + */ +char *strim(char *s) +{ + size_t size; + char *end; + + size = strlen(s); + if (!size) + return s; + + end = s + size - 1; + while (end >= s && isspace(*end)) + end--; + *(end + 1) = '\0'; + + return skip_spaces(s); +} +EXPORT_SYMBOL(strim); + +#ifndef __HAVE_ARCH_STRLEN +/** + * strlen - Find the length of a string + * @s: The string to be sized + */ +size_t strlen(const char *s) +{ + const char *sc; + + for (sc = s; *sc != '\0'; ++sc) + /* nothing */; + return sc - s; +} +EXPORT_SYMBOL(strlen); +#endif + +#ifndef __HAVE_ARCH_STRNLEN +/** + * strnlen - Find the length of a length-limited string + * @s: The string to be sized + * @count: The maximum number of bytes to search + */ +size_t strnlen(const char *s, size_t count) +{ + const char *sc; + + for (sc = s; count-- && *sc != '\0'; ++sc) + /* nothing */; + return sc - s; +} +EXPORT_SYMBOL(strnlen); +#endif + +#ifndef __HAVE_ARCH_STRSPN +/** + * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept + * @s: The string to be searched + * @accept: The string to search for + */ +size_t strspn(const char *s, const char *accept) +{ + const char *p; + const char *a; + size_t count = 0; + + for (p = s; *p != '\0'; ++p) { + for (a = accept; *a != '\0'; ++a) { + if (*p == *a) + break; + } + if (*a == '\0') + return count; + ++count; + } + return count; +} + +EXPORT_SYMBOL(strspn); +#endif + +#ifndef __HAVE_ARCH_STRCSPN +/** + * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject + * @s: The string to be searched + * @reject: The string to avoid + */ +size_t strcspn(const char *s, const char *reject) +{ + const char *p; + const char *r; + size_t count = 0; + + for (p = s; *p != '\0'; ++p) { + for (r = reject; *r != '\0'; ++r) { + if (*p == *r) + return count; + } + ++count; + } + return count; +} +EXPORT_SYMBOL(strcspn); +#endif + +#ifndef __HAVE_ARCH_STRPBRK +/** + * strpbrk - Find the first occurrence of a set of characters + * @cs: The string to be searched + * @ct: The characters to search for + */ +char *strpbrk(const char *cs, const char *ct) +{ + const char *sc1, *sc2; + + for (sc1 = cs; *sc1 != '\0'; ++sc1) { + for (sc2 = ct; *sc2 != '\0'; ++sc2) { + if (*sc1 == *sc2) + return (char *)sc1; + } + } + return NULL; +} +EXPORT_SYMBOL(strpbrk); +#endif + +#ifndef __HAVE_ARCH_STRSEP +/** + * strsep - Split a string into tokens + * @s: The string to be searched + * @ct: The characters to search for + * + * strsep() updates @s to point after the token, ready for the next call. + * + * It returns empty tokens, too, behaving exactly like the libc function + * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. + * Same semantics, slimmer shape. ;) + */ +char *strsep(char **s, const char *ct) +{ + char *sbegin = *s; + char *end; + + if (sbegin == NULL) + return NULL; + + end = strpbrk(sbegin, ct); + if (end) + *end++ = '\0'; + *s = end; + return sbegin; +} +EXPORT_SYMBOL(strsep); +#endif + +/** + * sysfs_streq - return true if strings are equal, modulo trailing newline + * @s1: one string + * @s2: another string + * + * This routine returns true iff two strings are equal, treating both + * NUL and newline-then-NUL as equivalent string terminations. It's + * geared for use with sysfs input strings, which generally terminate + * with newlines but are compared against values without newlines. + */ +bool sysfs_streq(const char *s1, const char *s2) +{ + while (*s1 && *s1 == *s2) { + s1++; + s2++; + } + + if (*s1 == *s2) + return true; + if (!*s1 && *s2 == '\n' && !s2[1]) + return true; + if (*s1 == '\n' && !s1[1] && !*s2) + return true; + return false; +} +EXPORT_SYMBOL(sysfs_streq); + +/** + * match_string - matches given string in an array + * @array: array of strings + * @n: number of strings in the array or -1 for NULL terminated arrays + * @string: string to match with + * + * Return: + * index of a @string in the @array if matches, or %-EINVAL otherwise. + */ +int match_string(const char * const *array, size_t n, const char *string) +{ + int index; + const char *item; + + for (index = 0; index < n; index++) { + item = array[index]; + if (!item) + break; + if (!strcmp(item, string)) + return index; + } + + return -EINVAL; +} +EXPORT_SYMBOL(match_string); + +/** + * __sysfs_match_string - matches given string in an array + * @array: array of strings + * @n: number of strings in the array or -1 for NULL terminated arrays + * @str: string to match with + * + * Returns index of @str in the @array or -EINVAL, just like match_string(). + * Uses sysfs_streq instead of strcmp for matching. + */ +int __sysfs_match_string(const char * const *array, size_t n, const char *str) +{ + const char *item; + int index; + + for (index = 0; index < n; index++) { + item = array[index]; + if (!item) + break; + if (sysfs_streq(item, str)) + return index; + } + + return -EINVAL; +} +EXPORT_SYMBOL(__sysfs_match_string); + +#ifndef __HAVE_ARCH_MEMSET +/** + * memset - Fill a region of memory with the given value + * @s: Pointer to the start of the area. + * @c: The byte to fill the area with + * @count: The size of the area. + * + * Do not use memset() to access IO space, use memset_io() instead. + */ +void *memset(void *s, int c, size_t count) +{ + char *xs = s; + + while (count--) + *xs++ = c; + return s; +} +EXPORT_SYMBOL(memset); +#endif + +/** + * memzero_explicit - Fill a region of memory (e.g. sensitive + * keying data) with 0s. + * @s: Pointer to the start of the area. + * @count: The size of the area. + * + * Note: usually using memset() is just fine (!), but in cases + * where clearing out _local_ data at the end of a scope is + * necessary, memzero_explicit() should be used instead in + * order to prevent the compiler from optimising away zeroing. + * + * memzero_explicit() doesn't need an arch-specific version as + * it just invokes the one of memset() implicitly. + */ +void memzero_explicit(void *s, size_t count) +{ + memset(s, 0, count); + barrier_data(s); +} +EXPORT_SYMBOL(memzero_explicit); + +#ifndef __HAVE_ARCH_MEMSET16 +/** + * memset16() - Fill a memory area with a uint16_t + * @s: Pointer to the start of the area. + * @v: The value to fill the area with + * @count: The number of values to store + * + * Differs from memset() in that it fills with a uint16_t instead + * of a byte. Remember that @count is the number of uint16_ts to + * store, not the number of bytes. + */ +void *memset16(uint16_t *s, uint16_t v, size_t count) +{ + uint16_t *xs = s; + + while (count--) + *xs++ = v; + return s; +} +EXPORT_SYMBOL(memset16); +#endif + +#ifndef __HAVE_ARCH_MEMSET32 +/** + * memset32() - Fill a memory area with a uint32_t + * @s: Pointer to the start of the area. + * @v: The value to fill the area with + * @count: The number of values to store + * + * Differs from memset() in that it fills with a uint32_t instead + * of a byte. Remember that @count is the number of uint32_ts to + * store, not the number of bytes. + */ +void *memset32(uint32_t *s, uint32_t v, size_t count) +{ + uint32_t *xs = s; + + while (count--) + *xs++ = v; + return s; +} +EXPORT_SYMBOL(memset32); +#endif + +#ifndef __HAVE_ARCH_MEMSET64 +/** + * memset64() - Fill a memory area with a uint64_t + * @s: Pointer to the start of the area. + * @v: The value to fill the area with + * @count: The number of values to store + * + * Differs from memset() in that it fills with a uint64_t instead + * of a byte. Remember that @count is the number of uint64_ts to + * store, not the number of bytes. + */ +void *memset64(uint64_t *s, uint64_t v, size_t count) +{ + uint64_t *xs = s; + + while (count--) + *xs++ = v; + return s; +} +EXPORT_SYMBOL(memset64); +#endif + +#ifndef __HAVE_ARCH_MEMCPY +/** + * memcpy - Copy one area of memory to another + * @dest: Where to copy to + * @src: Where to copy from + * @count: The size of the area. + * + * You should not use this function to access IO space, use memcpy_toio() + * or memcpy_fromio() instead. + */ +void *memcpy(void *dest, const void *src, size_t count) +{ + char *tmp = dest; + const char *s = src; + + while (count--) + *tmp++ = *s++; + return dest; +} +EXPORT_SYMBOL(memcpy); +#endif + +#ifndef __HAVE_ARCH_MEMMOVE +/** + * memmove - Copy one area of memory to another + * @dest: Where to copy to + * @src: Where to copy from + * @count: The size of the area. + * + * Unlike memcpy(), memmove() copes with overlapping areas. + */ +void *memmove(void *dest, const void *src, size_t count) +{ + char *tmp; + const char *s; + + if (dest <= src) { + tmp = dest; + s = src; + while (count--) + *tmp++ = *s++; + } else { + tmp = dest; + tmp += count; + s = src; + s += count; + while (count--) + *--tmp = *--s; + } + return dest; +} +EXPORT_SYMBOL(memmove); +#endif + +#ifndef __HAVE_ARCH_MEMCMP +/** + * memcmp - Compare two areas of memory + * @cs: One area of memory + * @ct: Another area of memory + * @count: The size of the area. + */ +#undef memcmp +__visible int memcmp(const void *cs, const void *ct, size_t count) +{ + const unsigned char *su1, *su2; + int res = 0; + + for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) + if ((res = *su1 - *su2) != 0) + break; + return res; +} +EXPORT_SYMBOL(memcmp); +#endif + +#ifndef __HAVE_ARCH_BCMP +/** + * bcmp - returns 0 if and only if the buffers have identical contents. + * @a: pointer to first buffer. + * @b: pointer to second buffer. + * @len: size of buffers. + * + * The sign or magnitude of a non-zero return value has no particular + * meaning, and architectures may implement their own more efficient bcmp(). So + * while this particular implementation is a simple (tail) call to memcmp, do + * not rely on anything but whether the return value is zero or non-zero. + */ +#undef bcmp +int bcmp(const void *a, const void *b, size_t len) +{ + return memcmp(a, b, len); +} +EXPORT_SYMBOL(bcmp); +#endif + +#ifndef __HAVE_ARCH_MEMSCAN +/** + * memscan - Find a character in an area of memory. + * @addr: The memory area + * @c: The byte to search for + * @size: The size of the area. + * + * returns the address of the first occurrence of @c, or 1 byte past + * the area if @c is not found + */ +void *memscan(void *addr, int c, size_t size) +{ + unsigned char *p = addr; + + while (size) { + if (*p == c) + return (void *)p; + p++; + size--; + } + return (void *)p; +} +EXPORT_SYMBOL(memscan); +#endif + +#ifndef __HAVE_ARCH_STRSTR +/** + * strstr - Find the first substring in a %NUL terminated string + * @s1: The string to be searched + * @s2: The string to search for + */ +char *strstr(const char *s1, const char *s2) +{ + size_t l1, l2; + + l2 = strlen(s2); + if (!l2) + return (char *)s1; + l1 = strlen(s1); + while (l1 >= l2) { + l1--; + if (!memcmp(s1, s2, l2)) + return (char *)s1; + s1++; + } + return NULL; +} +EXPORT_SYMBOL(strstr); +#endif + +#ifndef __HAVE_ARCH_STRNSTR +/** + * strnstr - Find the first substring in a length-limited string + * @s1: The string to be searched + * @s2: The string to search for + * @len: the maximum number of characters to search + */ +char *strnstr(const char *s1, const char *s2, size_t len) +{ + size_t l2; + + l2 = strlen(s2); + if (!l2) + return (char *)s1; + while (len >= l2) { + len--; + if (!memcmp(s1, s2, l2)) + return (char *)s1; + s1++; + } + return NULL; +} +EXPORT_SYMBOL(strnstr); +#endif + +#ifndef __HAVE_ARCH_MEMCHR +/** + * memchr - Find a character in an area of memory. + * @s: The memory area + * @c: The byte to search for + * @n: The size of the area. + * + * returns the address of the first occurrence of @c, or %NULL + * if @c is not found + */ +void *memchr(const void *s, int c, size_t n) +{ + const unsigned char *p = s; + while (n-- != 0) { + if ((unsigned char)c == *p++) { + return (void *)(p - 1); + } + } + return NULL; +} +EXPORT_SYMBOL(memchr); +#endif + +static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) +{ + while (bytes) { + if (*start != value) + return (void *)start; + start++; + bytes--; + } + return NULL; +} + +/** + * memchr_inv - Find an unmatching character in an area of memory. + * @start: The memory area + * @c: Find a character other than c + * @bytes: The size of the area. + * + * returns the address of the first character other than @c, or %NULL + * if the whole buffer contains just @c. + */ +void *memchr_inv(const void *start, int c, size_t bytes) +{ + u8 value = c; + u64 value64; + unsigned int words, prefix; + + if (bytes <= 16) + return check_bytes8(start, value, bytes); + + value64 = value; +#if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 + value64 *= 0x0101010101010101ULL; +#elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) + value64 *= 0x01010101; + value64 |= value64 << 32; +#else + value64 |= value64 << 8; + value64 |= value64 << 16; + value64 |= value64 << 32; +#endif + + prefix = (unsigned long)start % 8; + if (prefix) { + u8 *r; + + prefix = 8 - prefix; + r = check_bytes8(start, value, prefix); + if (r) + return r; + start += prefix; + bytes -= prefix; + } + + words = bytes / 8; + + while (words) { + if (*(u64 *)start != value64) + return check_bytes8(start, value, 8); + start += 8; + words--; + } + + return check_bytes8(start, value, bytes % 8); +} +EXPORT_SYMBOL(memchr_inv); + +/** + * strreplace - Replace all occurrences of character in string. + * @s: The string to operate on. + * @old: The character being replaced. + * @new: The character @old is replaced with. + * + * Returns pointer to the nul byte at the end of @s. + */ +char *strreplace(char *s, char old, char new) +{ + for (; *s; ++s) + if (*s == old) + *s = new; + return s; +} +EXPORT_SYMBOL(strreplace); + +void fortify_panic(const char *name) +{ + pr_emerg("detected buffer overflow in %s\n", name); + BUG(); +} +EXPORT_SYMBOL(fortify_panic); |