path: root/include/linux/string.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_STRING_H_
#define _LINUX_STRING_H_

#include <linux/args.h>
#include <linux/array_size.h>
#include <linux/cleanup.h>	/* for DEFINE_FREE() */
#include <linux/compiler.h>	/* for inline */
#include <linux/types.h>	/* for size_t */
#include <linux/stddef.h>	/* for NULL */
#include <linux/err.h>		/* for ERR_PTR() */
#include <linux/errno.h>	/* for E2BIG */
#include <linux/overflow.h>	/* for check_mul_overflow() */
#include <linux/stdarg.h>
#include <uapi/linux/string.h>

extern char *strndup_user(const char __user *, long);
extern void *memdup_user(const void __user *, size_t) __realloc_size(2);
extern void *vmemdup_user(const void __user *, size_t) __realloc_size(2);
extern void *memdup_user_nul(const void __user *, size_t);

/**
 * memdup_array_user - duplicate array from user space
 * @src: source address in user space
 * @n: number of array members to copy
 * @size: size of one array member
 *
 * Return: an ERR_PTR() on failure. Result is physically
 * contiguous, to be freed by kfree().
 */
static inline __realloc_size(2, 3)
void *memdup_array_user(const void __user *src, size_t n, size_t size)
{
	size_t nbytes;

	if (check_mul_overflow(n, size, &nbytes))
		return ERR_PTR(-EOVERFLOW);

	return memdup_user(src, nbytes);
}

/**
 * vmemdup_array_user - duplicate array from user space
 * @src: source address in user space
 * @n: number of array members to copy
 * @size: size of one array member
 *
 * Return: an ERR_PTR() on failure. Result may be not
 * physically contiguous. Use kvfree() to free.
 */
static inline __realloc_size(2, 3)
void *vmemdup_array_user(const void __user *src, size_t n, size_t size)
{
	size_t nbytes;

	if (check_mul_overflow(n, size, &nbytes))
		return ERR_PTR(-EOVERFLOW);

	return vmemdup_user(src, nbytes);
}

/*
 * Include machine specific inline routines
 */
#include <asm/string.h>

#ifndef __HAVE_ARCH_STRCPY
extern char * strcpy(char *,const char *);
#endif
#ifndef __HAVE_ARCH_STRNCPY
extern char * strncpy(char *,const char *, __kernel_size_t);
#endif
ssize_t sized_strscpy(char *, const char *, size_t);

/*
 * The 2 argument style can only be used when dst is an array with a
 * known size.
 */
#define __strscpy0(dst, src, ...)	\
	sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst) +	\
				__must_be_cstr(dst) + __must_be_cstr(src))
#define __strscpy1(dst, src, size)	\
	sized_strscpy(dst, src, size + __must_be_cstr(dst) + __must_be_cstr(src))

#define __strscpy_pad0(dst, src, ...)	\
	sized_strscpy_pad(dst, src, sizeof(dst) + __must_be_array(dst) +	\
				    __must_be_cstr(dst) + __must_be_cstr(src))
#define __strscpy_pad1(dst, src, size)	\
	sized_strscpy_pad(dst, src, size + __must_be_cstr(dst) + __must_be_cstr(src))

/**
 * strscpy - Copy a C-string into a sized buffer
 * @dst: Where to copy the string to
 * @src: Where to copy the string from
 * @...: Size of destination buffer (optional)
 *
 * Copy the source string @src, or as much of it as fits, into the
 * destination @dst buffer. The behavior is undefined if the string
 * buffers overlap. The destination @dst buffer is always NUL terminated,
 * unless it's zero-sized.
 *
 * The size argument @... is only required when @dst is not an array, or
 * when the copy needs to be smaller than sizeof(@dst).
 *
 * Preferred to strncpy() since it always returns a valid string, and
 * doesn't unnecessarily force the tail of the destination buffer to be
 * zero padded. If padding is desired please use strscpy_pad().
 *
 * Returns the number of characters copied in @dst (not including the
 * trailing %NUL) or -E2BIG if @size is 0 or the copy from @src was
 * truncated.
 */
#define strscpy(dst, src, ...)	\
	CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)

#define sized_strscpy_pad(dest, src, count)	({			\
	char *__dst = (dest);						\
	const char *__src = (src);					\
	const size_t __count = (count);					\
	ssize_t __wrote;						\
									\
	__wrote = sized_strscpy(__dst, __src, __count);			\
	if (__wrote >= 0 && __wrote < __count)				\
		memset(__dst + __wrote + 1, 0, __count - __wrote - 1);	\
	__wrote;							\
})

/**
 * strscpy_pad() - Copy a C-string into a sized buffer
 * @dst: Where to copy the string to
 * @src: Where to copy the string from
 * @...: 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, the
 * remaining bytes in the buffer will be filled with %NUL bytes.
 *
 * For full explanation of why you may want to consider using the
 * 'strscpy' functions please see the function docstring for strscpy().
 *
 * Returns:
 * * The number of characters copied (not including the trailing %NULs)
 * * -E2BIG if count is 0 or @src was truncated.
 */
#define strscpy_pad(dst, src, ...)	\
	CONCATENATE(__strscpy_pad, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)

#ifndef __HAVE_ARCH_STRCAT
extern char * strcat(char *, const char *);
#endif
#ifndef __HAVE_ARCH_STRNCAT
extern char * strncat(char *, const char *, __kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRLCAT
extern size_t strlcat(char *, const char *, __kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRCMP
extern int strcmp(const char *,const char *);
#endif
#ifndef __HAVE_ARCH_STRNCMP
extern int strncmp(const char *,const char *,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRCASECMP
extern int strcasecmp(const char *s1, const char *s2);
#endif
#ifndef __HAVE_ARCH_STRNCASECMP
extern int strncasecmp(const char *s1, const char *s2, size_t n);
#endif
#ifndef __HAVE_ARCH_STRCHR
extern char * strchr(const char *,int);
#endif
#ifndef __HAVE_ARCH_STRCHRNUL
extern char * strchrnul(const char *,int);
#endif
extern char * strnchrnul(const char *, size_t, int);
#ifndef __HAVE_ARCH_STRNCHR
extern char * strnchr(const char *, size_t, int);
#endif
#ifndef __HAVE_ARCH_STRRCHR
extern char * strrchr(const char *,int);
#endif
extern char * __must_check skip_spaces(const char *);

extern char *strim(char *);

static inline __must_check char *strstrip(char *str)
{
	return strim(str);
}

#ifndef __HAVE_ARCH_STRSTR
extern char * strstr(const char *, const char *);
#endif
#ifndef __HAVE_ARCH_STRNSTR
extern char * strnstr(const char *, const char *, size_t);
#endif
#ifndef __HAVE_ARCH_STRLEN
extern __kernel_size_t strlen(const char *);
#endif
#ifndef __HAVE_ARCH_STRNLEN
extern __kernel_size_t strnlen(const char *,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_STRPBRK
extern char * strpbrk(const char *,const char *);
#endif
#ifndef __HAVE_ARCH_STRSEP
extern char * strsep(char **,const char *);
#endif
#ifndef __HAVE_ARCH_STRSPN
extern __kernel_size_t strspn(const char *,const char *);
#endif
#ifndef __HAVE_ARCH_STRCSPN
extern __kernel_size_t strcspn(const char *,const char *);
#endif

#ifndef __HAVE_ARCH_MEMSET
extern void * memset(void *,int,__kernel_size_t);
#endif

#ifndef __HAVE_ARCH_MEMSET16
extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
#endif

#ifndef __HAVE_ARCH_MEMSET32
extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
#endif

#ifndef __HAVE_ARCH_MEMSET64
extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
#endif

static inline void *memset_l(unsigned long *p, unsigned long v,
		__kernel_size_t n)
{
	if (BITS_PER_LONG == 32)
		return memset32((uint32_t *)p, v, n);
	else
		return memset64((uint64_t *)p, v, n);
}

static inline void *memset_p(void **p, void *v, __kernel_size_t n)
{
	if (BITS_PER_LONG == 32)
		return memset32((uint32_t *)p, (uintptr_t)v, n);
	else
		return memset64((uint64_t *)p, (uintptr_t)v, n);
}

extern void **__memcat_p(void **a, void **b);
#define memcat_p(a, b) ({					\
	BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)),		\
			 "type mismatch in memcat_p()");	\
	(typeof(*a) *)__memcat_p((void **)(a), (void **)(b));	\
})

#ifndef __HAVE_ARCH_MEMCPY
extern void * memcpy(void *,const void *,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_MEMMOVE
extern void * memmove(void *,const void *,__kernel_size_t);
#endif
#ifndef __HAVE_ARCH_MEMSCAN
extern void *