string.c

  1// SPDX-License-Identifier: GPL-2.0
  2#define IN_BOOT_STRING_C 1
  3#include <linux/ctype.h>
  4#include <linux/kernel.h>
  5#include <linux/errno.h>
  6#undef CONFIG_KASAN
  7#undef CONFIG_KASAN_GENERIC
  8#undef CONFIG_KMSAN
  9#include "../lib/string.c"
 10
 11/*
 12 * Duplicate some functions from the common lib/string.c
 13 * instead of fully including it.
 14 */
 15
 16int strncmp(const char *cs, const char *ct, size_t count)
 17{
 18	unsigned char c1, c2;
 19
 20	while (count) {
 21		c1 = *cs++;
 22		c2 = *ct++;
 23		if (c1 != c2)
 24			return c1 < c2 ? -1 : 1;
 25		if (!c1)
 26			break;
 27		count--;
 28	}
 29	return 0;
 30}
 31
 32ssize_t sized_strscpy(char *dst, const char *src, size_t count)
 33{
 34	size_t len;
 35
 36	if (count == 0)
 37		return -E2BIG;
 38	len = strnlen(src, count - 1);
 39	memcpy(dst, src, len);
 40	dst[len] = '\0';
 41	return src[len] ? -E2BIG : len;
 42}
 43
 44void *memset64(uint64_t *s, uint64_t v, size_t count)
 45{
 46	uint64_t *xs = s;
 47
 48	while (count--)
 49		*xs++ = v;
 50	return s;
 51}
 52
 53char *skip_spaces(const char *str)
 54{
 55	while (isspace(*str))
 56		++str;
 57	return (char *)str;
 58}
 59
 60char *strim(char *s)
 61{
 62	size_t size;
 63	char *end;
 64
 65	size = strlen(s);
 66	if (!size)
 67		return s;
 68
 69	end = s + size - 1;
 70	while (end >= s && isspace(*end))
 71		end--;
 72	*(end + 1) = '\0';
 73
 74	return skip_spaces(s);
 75}
 76
 77/* Works only for digits and letters, but small and fast */
 78#define TOLOWER(x) ((x) | 0x20)
 79
 80static unsigned int simple_guess_base(const char *cp)
 81{
 82	if (cp[0] == '0') {
 83		if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2]))
 84			return 16;
 85		else
 86			return 8;
 87	} else {
 88		return 10;
 89	}
 90}
 91
 92/**
 93 * simple_strtoull - convert a string to an unsigned long long
 94 * @cp: The start of the string
 95 * @endp: A pointer to the end of the parsed string will be placed here
 96 * @base: The number base to use
 97 */
 98
 99unsigned long long simple_strtoull(const char *cp, char **endp,
100				   unsigned int base)
101{
102	unsigned long long result = 0;
103
104	if (!base)
105		base = simple_guess_base(cp);
106
107	if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
108		cp += 2;
109
110	while (isxdigit(*cp)) {
111		unsigned int value;
112
113		value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
114		if (value >= base)
115			break;
116		result = result * base + value;
117		cp++;
118	}
119	if (endp)
120		*endp = (char *)cp;
121
122	return result;
123}
124
125long simple_strtol(const char *cp, char **endp, unsigned int base)
126{
127	if (*cp == '-')
128		return -simple_strtoull(cp + 1, endp, base);
129
130	return simple_strtoull(cp, endp, base);
131}
132
133int kstrtobool(const char *s, bool *res)
134{
135	if (!s)
136		return -EINVAL;
137
138	switch (s[0]) {
139	case 'y':
140	case 'Y':
141	case '1':
142		*res = true;
143		return 0;
144	case 'n':
145	case 'N':
146	case '0':
147		*res = false;
148		return 0;
149	case 'o':
150	case 'O':
151		switch (s[1]) {
152		case 'n':
153		case 'N':
154			*res = true;
155			return 0;
156		case 'f':
157		case 'F':
158			*res = false;
159			return 0;
160		default:
161			break;
162		}
163	default:
164		break;
165	}
166
167	return -EINVAL;
168}