LXR linux/arch/arm/boot/compressed/string.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * arch/arm/boot/compressed/string.c
   4 *
   5 * Small subset of simple string routines
   6 */
   7
   8#include <linux/string.h>
   9
  10/*
  11 * The decompressor is built without KASan but uses the same redirects as the
  12 * rest of the kernel when CONFIG_KASAN is enabled, defining e.g. memcpy()
  13 * to __memcpy() but since we are not linking with the main kernel string
  14 * library in the decompressor, that will lead to link failures.
  15 *
  16 * Undefine KASan's versions, define the wrapped functions and alias them to
  17 * the right names so that when e.g. __memcpy() appear in the code, it will
  18 * still be linked to this local version of memcpy().
  19 */
  20#ifdef CONFIG_KASAN
  21#undef memcpy
  22#undef memmove
  23#undef memset
  24void *__memcpy(void *__dest, __const void *__src, size_t __n) __alias(memcpy);
  25void *__memmove(void *__dest, __const void *__src, size_t count) __alias(memmove);
  26void *__memset(void *s, int c, size_t count) __alias(memset);
  27#endif
  28
  29void *memcpy(void *__dest, __const void *__src, size_t __n)
  30{
  31        int i = 0;
  32        unsigned char *d = (unsigned char *)__dest, *s = (unsigned char *)__src;
  33
  34        for (i = __n >> 3; i > 0; i--) {
  35                *d++ = *s++;
  36                *d++ = *s++;
  37                *d++ = *s++;
  38                *d++ = *s++;
  39                *d++ = *s++;
  40                *d++ = *s++;
  41                *d++ = *s++;
  42                *d++ = *s++;
  43        }
  44
  45        if (__n & 1 << 2) {
  46                *d++ = *s++;
  47                *d++ = *s++;
  48                *d++ = *s++;
  49                *d++ = *s++;
  50        }
  51
  52        if (__n & 1 << 1) {
  53                *d++ = *s++;
  54                *d++ = *s++;
  55        }
  56
  57        if (__n & 1)
  58                *d++ = *s++;
  59
  60        return __dest;
  61}
  62
  63void *memmove(void *__dest, __const void *__src, size_t count)
  64{
  65        unsigned char *d = __dest;
  66        const unsigned char *s = __src;
  67
  68        if (__dest == __src)
  69                return __dest;
  70
  71        if (__dest < __src)
  72                return memcpy(__dest, __src, count);
  73
  74        while (count--)
  75                d[count] = s[count];
  76        return __dest;
  77}
  78
  79size_t strlen(const char *s)
  80{
  81        const char *sc = s;
  82
  83        while (*sc != '\0')
  84                sc++;
  85        return sc - s;
  86}
  87
  88size_t strnlen(const char *s, size_t count)
  89{
  90        const char *sc;
  91
  92        for (sc = s; count-- && *sc != '\0'; ++sc)
  93                /* nothing */;
  94        return sc - s;
  95}
  96
  97int memcmp(const void *cs, const void *ct, size_t count)
  98{
  99        const unsigned char *su1 = cs, *su2 = ct, *end = su1 + count;
 100        int res = 0;
 101
 102        while (su1 < end) {
 103                res = *su1++ - *su2++;
 104                if (res)
 105                        break;
 106        }
 107        return res;
 108}
 109
 110int strcmp(const char *cs, const char *ct)
 111{
 112        unsigned char c1, c2;
 113        int res = 0;
 114
 115        do {
 116                c1 = *cs++;
 117                c2 = *ct++;
 118                res = c1 - c2;
 119                if (res)
 120                        break;
 121        } while (c1);
 122        return res;
 123}
 124
 125void *memchr(const void *s, int c, size_t count)
 126{
 127        const unsigned char *p = s;
 128
 129        while (count--)
 130                if ((unsigned char)c == *p++)
 131                        return (void *)(p - 1);
 132        return NULL;
 133}
 134
 135char *strchr(const char *s, int c)
 136{
 137        while (*s != (char)c)
 138                if (*s++ == '\0')
 139                        return NULL;
 140        return (char *)s;
 141}
 142
 143char *strrchr(const char *s, int c)
 144{
 145        const char *last = NULL;
 146        do {
 147                if (*s == (char)c)
 148                        last = s;
 149        } while (*s++);
 150        return (char *)last;
 151}
 152
 153#undef memset
 154
 155void *memset(void *s, int c, size_t count)
 156{
 157        char *xs = s;
 158        while (count--)
 159                *xs++ = c;
 160        return s;
 161}
 162