|  | /* SPDX-License-Identifier: GPL-2.0 */ | 
|  | #ifndef _LINUX_STRING_H_ | 
|  | #define _LINUX_STRING_H_ | 
|  |  | 
|  |  | 
|  | #include <linux/compiler.h>	/* for inline */ | 
|  | #include <linux/types.h>	/* for size_t */ | 
|  | #include <linux/stddef.h>	/* for NULL */ | 
|  | #include <stdarg.h> | 
|  | #include <uapi/linux/string.h> | 
|  |  | 
|  | extern char *strndup_user(const char __user *, long); | 
|  | extern void *memdup_user(const void __user *, size_t); | 
|  | extern void *vmemdup_user(const void __user *, size_t); | 
|  | extern void *memdup_user_nul(const void __user *, size_t); | 
|  |  | 
|  | /* | 
|  | * 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 | 
|  | #ifndef __HAVE_ARCH_STRLCPY | 
|  | size_t strlcpy(char *, const char *, size_t); | 
|  | #endif | 
|  | #ifndef __HAVE_ARCH_STRSCPY | 
|  | ssize_t strscpy(char *, const char *, size_t); | 
|  | #endif | 
|  |  | 
|  | /* Wraps calls to strscpy()/memset(), no arch specific code required */ | 
|  | ssize_t strscpy_pad(char *dest, const char *src, size_t count); | 
|  |  | 
|  | #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 | 
|  | #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 * memscan(void *,int,__kernel_size_t); | 
|  | #endif | 
|  | #ifndef __HAVE_ARCH_MEMCMP | 
|  | extern int memcmp(const void *,const void *,__kernel_size_t); | 
|  | #endif | 
|  | #ifndef __HAVE_ARCH_BCMP | 
|  | extern int bcmp(const void *,const void *,__kernel_size_t); | 
|  | #endif | 
|  | #ifndef __HAVE_ARCH_MEMCHR | 
|  | extern void * memchr(const void *,int,__kernel_size_t); | 
|  | #endif | 
|  | #ifndef __HAVE_ARCH_MEMCPY_MCSAFE | 
|  | static inline __must_check unsigned long memcpy_mcsafe(void *dst, | 
|  | const void *src, size_t cnt) | 
|  | { | 
|  | memcpy(dst, src, cnt); | 
|  | return 0; | 
|  | } | 
|  | #endif | 
|  | #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE | 
|  | static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) | 
|  | { | 
|  | memcpy(dst, src, cnt); | 
|  | } | 
|  | #endif | 
|  | void *memchr_inv(const void *s, int c, size_t n); | 
|  | char *strreplace(char *s, char old, char new); | 
|  |  | 
|  | extern void kfree_const(const void *x); | 
|  |  | 
|  | extern char *kstrdup(const char *s, gfp_t gfp) __malloc; | 
|  | extern const char *kstrdup_const(const char *s, gfp_t gfp); | 
|  | extern char *kstrndup(const char *s, size_t len, gfp_t gfp); | 
|  | extern void *kmemdup(const void *src, size_t len, gfp_t gfp); | 
|  | extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); | 
|  |  | 
|  | extern char **argv_split(gfp_t gfp, const char *str, int *argcp); | 
|  | extern void argv_free(char **argv); | 
|  |  | 
|  | extern bool sysfs_streq(const char *s1, const char *s2); | 
|  | extern int kstrtobool(const char *s, bool *res); | 
|  | static inline int strtobool(const char *s, bool *res) | 
|  | { | 
|  | return kstrtobool(s, res); | 
|  | } | 
|  |  | 
|  | int match_string(const char * const *array, size_t n, const char *string); | 
|  | int __sysfs_match_string(const char * const *array, size_t n, const char *s); | 
|  |  | 
|  | /** | 
|  | * sysfs_match_string - matches given string in an array | 
|  | * @_a: array of strings | 
|  | * @_s: string to match with | 
|  | * | 
|  | * Helper for __sysfs_match_string(). Calculates the size of @a automatically. | 
|  | */ | 
|  | #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s) | 
|  |  | 
|  | #ifdef CONFIG_BINARY_PRINTF | 
|  | int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); | 
|  | int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf); | 
|  | int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4); | 
|  | #endif | 
|  |  | 
|  | extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, | 
|  | const void *from, size_t available); | 
|  |  | 
|  | int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); | 
|  |  | 
|  | /** | 
|  | * strstarts - does @str start with @prefix? | 
|  | * @str: string to examine | 
|  | * @prefix: prefix to look for. | 
|  | */ | 
|  | static inline bool strstarts(const char *str, const char *prefix) | 
|  | { | 
|  | return strncmp(str, prefix, strlen(prefix)) == 0; | 
|  | } | 
|  |  | 
|  | size_t memweight(const void *ptr, size_t bytes); | 
|  |  | 
|  | /** | 
|  | * 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. | 
|  | */ | 
|  | static inline void memzero_explicit(void *s, size_t count) | 
|  | { | 
|  | memset(s, 0, count); | 
|  | barrier_data(s); | 
|  | } | 
|  |  | 
|  | /** | 
|  | * kbasename - return the last part of a pathname. | 
|  | * | 
|  | * @path: path to extract the filename from. | 
|  | */ | 
|  | static inline const char *kbasename(const char *path) | 
|  | { | 
|  | const char *tail = strrchr(path, '/'); | 
|  | return tail ? tail + 1 : path; | 
|  | } | 
|  |  | 
|  | #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline)) | 
|  | #define __RENAME(x) __asm__(#x) | 
|  |  | 
|  | void fortify_panic(const char *name) __noreturn __cold; | 
|  | void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter"); | 
|  | void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter"); | 
|  | void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter"); | 
|  | void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter"); | 
|  |  | 
|  | #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE) | 
|  |  | 
|  | #ifdef CONFIG_KASAN | 
|  | extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr); | 
|  | extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp); | 
|  | extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy); | 
|  | extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove); | 
|  | extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset); | 
|  | extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat); | 
|  | extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy); | 
|  | extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen); | 
|  | extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat); | 
|  | extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy); | 
|  | #else | 
|  | #define __underlying_memchr	__builtin_memchr | 
|  | #define __underlying_memcmp	__builtin_memcmp | 
|  | #define __underlying_memcpy	__builtin_memcpy | 
|  | #define __underlying_memmove	__builtin_memmove | 
|  | #define __underlying_memset	__builtin_memset | 
|  | #define __underlying_strcat	__builtin_strcat | 
|  | #define __underlying_strcpy	__builtin_strcpy | 
|  | #define __underlying_strlen	__builtin_strlen | 
|  | #define __underlying_strncat	__builtin_strncat | 
|  | #define __underlying_strncpy	__builtin_strncpy | 
|  | #endif | 
|  |  | 
|  | __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | if (__builtin_constant_p(size) && p_size < size) | 
|  | __write_overflow(); | 
|  | if (p_size < size) | 
|  | fortify_panic(__func__); | 
|  | return __underlying_strncpy(p, q, size); | 
|  | } | 
|  |  | 
|  | __FORTIFY_INLINE char *strcat(char *p, const char *q) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | if (p_size == (size_t)-1) | 
|  | return __underlying_strcat(p, q); | 
|  | if (strlcat(p, q, p_size) >= p_size) | 
|  | fortify_panic(__func__); | 
|  | return p; | 
|  | } | 
|  |  | 
|  | __FORTIFY_INLINE __kernel_size_t strlen(const char *p) | 
|  | { | 
|  | __kernel_size_t ret; | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  |  | 
|  | /* Work around gcc excess stack consumption issue */ | 
|  | if (p_size == (size_t)-1 || | 
|  | (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0')) | 
|  | return __underlying_strlen(p); | 
|  | ret = strnlen(p, p_size); | 
|  | if (p_size <= ret) | 
|  | fortify_panic(__func__); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen); | 
|  | __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size); | 
|  | if (p_size <= ret && maxlen != ret) | 
|  | fortify_panic(__func__); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* defined after fortified strlen to reuse it */ | 
|  | extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy); | 
|  | __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size) | 
|  | { | 
|  | size_t ret; | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | size_t q_size = __builtin_object_size(q, 0); | 
|  | if (p_size == (size_t)-1 && q_size == (size_t)-1) | 
|  | return __real_strlcpy(p, q, size); | 
|  | ret = strlen(q); | 
|  | if (size) { | 
|  | size_t len = (ret >= size) ? size - 1 : ret; | 
|  | if (__builtin_constant_p(len) && len >= p_size) | 
|  | __write_overflow(); | 
|  | if (len >= p_size) | 
|  | fortify_panic(__func__); | 
|  | __underlying_memcpy(p, q, len); | 
|  | p[len] = '\0'; | 
|  | } | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | /* defined after fortified strlen and strnlen to reuse them */ | 
|  | __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count) | 
|  | { | 
|  | size_t p_len, copy_len; | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | size_t q_size = __builtin_object_size(q, 0); | 
|  | if (p_size == (size_t)-1 && q_size == (size_t)-1) | 
|  | return __underlying_strncat(p, q, count); | 
|  | p_len = strlen(p); | 
|  | copy_len = strnlen(q, count); | 
|  | if (p_size < p_len + copy_len + 1) | 
|  | fortify_panic(__func__); | 
|  | __underlying_memcpy(p + p_len, q, copy_len); | 
|  | p[p_len + copy_len] = '\0'; | 
|  | return p; | 
|  | } | 
|  |  | 
|  | __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | if (__builtin_constant_p(size) && p_size < size) | 
|  | __write_overflow(); | 
|  | if (p_size < size) | 
|  | fortify_panic(__func__); | 
|  | return __underlying_memset(p, c, size); | 
|  | } | 
|  |  | 
|  | __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | size_t q_size = __builtin_object_size(q, 0); | 
|  | if (__builtin_constant_p(size)) { | 
|  | if (p_size < size) | 
|  | __write_overflow(); | 
|  | if (q_size < size) | 
|  | __read_overflow2(); | 
|  | } | 
|  | if (p_size < size || q_size < size) | 
|  | fortify_panic(__func__); | 
|  | return __underlying_memcpy(p, q, size); | 
|  | } | 
|  |  | 
|  | __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | size_t q_size = __builtin_object_size(q, 0); | 
|  | if (__builtin_constant_p(size)) { | 
|  | if (p_size < size) | 
|  | __write_overflow(); | 
|  | if (q_size < size) | 
|  | __read_overflow2(); | 
|  | } | 
|  | if (p_size < size || q_size < size) | 
|  | fortify_panic(__func__); | 
|  | return __underlying_memmove(p, q, size); | 
|  | } | 
|  |  | 
|  | extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan); | 
|  | __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | if (__builtin_constant_p(size) && p_size < size) | 
|  | __read_overflow(); | 
|  | if (p_size < size) | 
|  | fortify_panic(__func__); | 
|  | return __real_memscan(p, c, size); | 
|  | } | 
|  |  | 
|  | __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | size_t q_size = __builtin_object_size(q, 0); | 
|  | if (__builtin_constant_p(size)) { | 
|  | if (p_size < size) | 
|  | __read_overflow(); | 
|  | if (q_size < size) | 
|  | __read_overflow2(); | 
|  | } | 
|  | if (p_size < size || q_size < size) | 
|  | fortify_panic(__func__); | 
|  | return __underlying_memcmp(p, q, size); | 
|  | } | 
|  |  | 
|  | __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | if (__builtin_constant_p(size) && p_size < size) | 
|  | __read_overflow(); | 
|  | if (p_size < size) | 
|  | fortify_panic(__func__); | 
|  | return __underlying_memchr(p, c, size); | 
|  | } | 
|  |  | 
|  | void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv); | 
|  | __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | if (__builtin_constant_p(size) && p_size < size) | 
|  | __read_overflow(); | 
|  | if (p_size < size) | 
|  | fortify_panic(__func__); | 
|  | return __real_memchr_inv(p, c, size); | 
|  | } | 
|  |  | 
|  | extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup); | 
|  | __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | if (__builtin_constant_p(size) && p_size < size) | 
|  | __read_overflow(); | 
|  | if (p_size < size) | 
|  | fortify_panic(__func__); | 
|  | return __real_kmemdup(p, size, gfp); | 
|  | } | 
|  |  | 
|  | /* defined after fortified strlen and memcpy to reuse them */ | 
|  | __FORTIFY_INLINE char *strcpy(char *p, const char *q) | 
|  | { | 
|  | size_t p_size = __builtin_object_size(p, 0); | 
|  | size_t q_size = __builtin_object_size(q, 0); | 
|  | if (p_size == (size_t)-1 && q_size == (size_t)-1) | 
|  | return __underlying_strcpy(p, q); | 
|  | memcpy(p, q, strlen(q) + 1); | 
|  | return p; | 
|  | } | 
|  |  | 
|  | /* Don't use these outside the FORITFY_SOURCE implementation */ | 
|  | #undef __underlying_memchr | 
|  | #undef __underlying_memcmp | 
|  | #undef __underlying_memcpy | 
|  | #undef __underlying_memmove | 
|  | #undef __underlying_memset | 
|  | #undef __underlying_strcat | 
|  | #undef __underlying_strcpy | 
|  | #undef __underlying_strlen | 
|  | #undef __underlying_strncat | 
|  | #undef __underlying_strncpy | 
|  | #endif | 
|  |  | 
|  | /** | 
|  | * memcpy_and_pad - Copy one buffer to another with padding | 
|  | * @dest: Where to copy to | 
|  | * @dest_len: The destination buffer size | 
|  | * @src: Where to copy from | 
|  | * @count: The number of bytes to copy | 
|  | * @pad: Character to use for padding if space is left in destination. | 
|  | */ | 
|  | static inline void memcpy_and_pad(void *dest, size_t dest_len, | 
|  | const void *src, size_t count, int pad) | 
|  | { | 
|  | if (dest_len > count) { | 
|  | memcpy(dest, src, count); | 
|  | memset(dest + count, pad,  dest_len - count); | 
|  | } else | 
|  | memcpy(dest, src, dest_len); | 
|  | } | 
|  |  | 
|  | /** | 
|  | * str_has_prefix - Test if a string has a given prefix | 
|  | * @str: The string to test | 
|  | * @prefix: The string to see if @str starts with | 
|  | * | 
|  | * A common way to test a prefix of a string is to do: | 
|  | *  strncmp(str, prefix, sizeof(prefix) - 1) | 
|  | * | 
|  | * But this can lead to bugs due to typos, or if prefix is a pointer | 
|  | * and not a constant. Instead use str_has_prefix(). | 
|  | * | 
|  | * Returns: | 
|  | * * strlen(@prefix) if @str starts with @prefix | 
|  | * * 0 if @str does not start with @prefix | 
|  | */ | 
|  | static __always_inline size_t str_has_prefix(const char *str, const char *prefix) | 
|  | { | 
|  | size_t len = strlen(prefix); | 
|  | return strncmp(str, prefix, len) == 0 ? len : 0; | 
|  | } | 
|  |  | 
|  | #endif /* _LINUX_STRING_H_ */ |