string.c

// SPDX-License-Identifier: GPL-2.0
#define IN_BOOT_STRING_C 1
#include <linux/ctype.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#undef CONFIG_KASAN
#undef CONFIG_KASAN_GENERIC
#undef CONFIG_KMSAN
#include "../lib/string.c"

/*
 * Duplicate some functions from the common lib/string.c
 * instead of fully including it.
 */

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;
}

ssize_t sized_strscpy(char *dst, const char *src, size_t count)
{
	size_t len;

	if (count == 0)
		return -E2BIG;
	len = strnlen(src, count - 1);
	memcpy(dst, src, len);
	dst[len] = '\0';
	return src[len] ? -E2BIG : len;
}

void *memset64(uint64_t *s, uint64_t v, size_t count)
{
	uint64_t *xs = s;

	while (count--)
		*xs++ = v;
	return s;
}

char *skip_spaces(const char *str)
{
	while (isspace(*str))
		++str;
	return (char *)str;
}

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);
}

/* Works only for digits and letters, but small and fast */
#define TOLOWER(x) ((x) | 0x20)

static unsigned int simple_guess_base(const char *cp)
{
	if (cp[0] == '0') {
		if (TOLOWER(cp[1]) == 'x' && isxdigit(cp[2]))
			return 16;
		else
			return 8;
	} else {
		return 10;
	}
}

/**
 * simple_strtoull - convert a string to an unsigned long long
 * @cp: The start of the string
 * @endp: A pointer to the end of the parsed string will be placed here
 * @base: The number base to use
 */

unsigned long long simple_strtoull(const char *cp, char **endp,
				   unsigned int base)
{
	unsigned long long result = 0;

	if (!base)
		base = simple_guess_base(cp);

	if (base == 16 && cp[0] == '0' && TOLOWER(cp[1]) == 'x')
		cp += 2;

	while (isxdigit(*cp)) {
		unsigned int value;

		value = isdigit(*cp) ? *cp - '0' : TOLOWER(*cp) - 'a' + 10;
		if (value >= base)
			break;
		result = result * base + value;
		cp++;
	}
	if (endp)
		*endp = (char *)cp;

	return result;
}

long simple_strtol(const char *cp, char **endp, unsigned int base)
{
	if (*cp == '-')
		return -simple_strtoull(cp + 1, endp, base);

	return simple_strtoull(cp, endp, base);
}

int kstrtobool(const char *s, bool *res)
{
	if (!s)
		return -EINVAL;

	switch (s[0]) {
	case 'y':
	case 'Y':
	case '1':
		*res = true;
		return 0;
	case 'n':
	case 'N':
	case '0':
		*res = false;
		return 0;
	case 'o':
	case 'O':
		switch (s[1]) {
		case 'n':
		case 'N':
			*res = true;
			return 0;
		case 'f':
		case 'F':
			*res = false;
			return 0;
		default:
			break;
		}
	default:
		break;
	}

	return -EINVAL;
}