string.h (9518B)
1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_STRING_H_ 3#define _LINUX_STRING_H_ 4 5#include <linux/compiler.h> /* for inline */ 6#include <linux/types.h> /* for size_t */ 7#include <linux/stddef.h> /* for NULL */ 8#include <linux/errno.h> /* for E2BIG */ 9#include <linux/stdarg.h> 10#include <uapi/linux/string.h> 11 12extern char *strndup_user(const char __user *, long); 13extern void *memdup_user(const void __user *, size_t); 14extern void *vmemdup_user(const void __user *, size_t); 15extern void *memdup_user_nul(const void __user *, size_t); 16 17/* 18 * Include machine specific inline routines 19 */ 20#include <asm/string.h> 21 22#ifndef __HAVE_ARCH_STRCPY 23extern char * strcpy(char *,const char *); 24#endif 25#ifndef __HAVE_ARCH_STRNCPY 26extern char * strncpy(char *,const char *, __kernel_size_t); 27#endif 28#ifndef __HAVE_ARCH_STRLCPY 29size_t strlcpy(char *, const char *, size_t); 30#endif 31#ifndef __HAVE_ARCH_STRSCPY 32ssize_t strscpy(char *, const char *, size_t); 33#endif 34 35/* Wraps calls to strscpy()/memset(), no arch specific code required */ 36ssize_t strscpy_pad(char *dest, const char *src, size_t count); 37 38#ifndef __HAVE_ARCH_STRCAT 39extern char * strcat(char *, const char *); 40#endif 41#ifndef __HAVE_ARCH_STRNCAT 42extern char * strncat(char *, const char *, __kernel_size_t); 43#endif 44#ifndef __HAVE_ARCH_STRLCAT 45extern size_t strlcat(char *, const char *, __kernel_size_t); 46#endif 47#ifndef __HAVE_ARCH_STRCMP 48extern int strcmp(const char *,const char *); 49#endif 50#ifndef __HAVE_ARCH_STRNCMP 51extern int strncmp(const char *,const char *,__kernel_size_t); 52#endif 53#ifndef __HAVE_ARCH_STRCASECMP 54extern int strcasecmp(const char *s1, const char *s2); 55#endif 56#ifndef __HAVE_ARCH_STRNCASECMP 57extern int strncasecmp(const char *s1, const char *s2, size_t n); 58#endif 59#ifndef __HAVE_ARCH_STRCHR 60extern char * strchr(const char *,int); 61#endif 62#ifndef __HAVE_ARCH_STRCHRNUL 63extern char * strchrnul(const char *,int); 64#endif 65extern char * strnchrnul(const char *, size_t, int); 66#ifndef __HAVE_ARCH_STRNCHR 67extern char * strnchr(const char *, size_t, int); 68#endif 69#ifndef __HAVE_ARCH_STRRCHR 70extern char * strrchr(const char *,int); 71#endif 72extern char * __must_check skip_spaces(const char *); 73 74extern char *strim(char *); 75 76static inline __must_check char *strstrip(char *str) 77{ 78 return strim(str); 79} 80 81#ifndef __HAVE_ARCH_STRSTR 82extern char * strstr(const char *, const char *); 83#endif 84#ifndef __HAVE_ARCH_STRNSTR 85extern char * strnstr(const char *, const char *, size_t); 86#endif 87#ifndef __HAVE_ARCH_STRLEN 88extern __kernel_size_t strlen(const char *); 89#endif 90#ifndef __HAVE_ARCH_STRNLEN 91extern __kernel_size_t strnlen(const char *,__kernel_size_t); 92#endif 93#ifndef __HAVE_ARCH_STRPBRK 94extern char * strpbrk(const char *,const char *); 95#endif 96#ifndef __HAVE_ARCH_STRSEP 97extern char * strsep(char **,const char *); 98#endif 99#ifndef __HAVE_ARCH_STRSPN 100extern __kernel_size_t strspn(const char *,const char *); 101#endif 102#ifndef __HAVE_ARCH_STRCSPN 103extern __kernel_size_t strcspn(const char *,const char *); 104#endif 105 106#ifndef __HAVE_ARCH_MEMSET 107extern void * memset(void *,int,__kernel_size_t); 108#endif 109 110#ifndef __HAVE_ARCH_MEMSET16 111extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); 112#endif 113 114#ifndef __HAVE_ARCH_MEMSET32 115extern void *memset32(uint32_t *, uint32_t, __kernel_size_t); 116#endif 117 118#ifndef __HAVE_ARCH_MEMSET64 119extern void *memset64(uint64_t *, uint64_t, __kernel_size_t); 120#endif 121 122static inline void *memset_l(unsigned long *p, unsigned long v, 123 __kernel_size_t n) 124{ 125 if (BITS_PER_LONG == 32) 126 return memset32((uint32_t *)p, v, n); 127 else 128 return memset64((uint64_t *)p, v, n); 129} 130 131static inline void *memset_p(void **p, void *v, __kernel_size_t n) 132{ 133 if (BITS_PER_LONG == 32) 134 return memset32((uint32_t *)p, (uintptr_t)v, n); 135 else 136 return memset64((uint64_t *)p, (uintptr_t)v, n); 137} 138 139extern void **__memcat_p(void **a, void **b); 140#define memcat_p(a, b) ({ \ 141 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \ 142 "type mismatch in memcat_p()"); \ 143 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \ 144}) 145 146#ifndef __HAVE_ARCH_MEMCPY 147extern void * memcpy(void *,const void *,__kernel_size_t); 148#endif 149#ifndef __HAVE_ARCH_MEMMOVE 150extern void * memmove(void *,const void *,__kernel_size_t); 151#endif 152#ifndef __HAVE_ARCH_MEMSCAN 153extern void * memscan(void *,int,__kernel_size_t); 154#endif 155#ifndef __HAVE_ARCH_MEMCMP 156extern int memcmp(const void *,const void *,__kernel_size_t); 157#endif 158#ifndef __HAVE_ARCH_BCMP 159extern int bcmp(const void *,const void *,__kernel_size_t); 160#endif 161#ifndef __HAVE_ARCH_MEMCHR 162extern void * memchr(const void *,int,__kernel_size_t); 163#endif 164#ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE 165static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) 166{ 167 memcpy(dst, src, cnt); 168} 169#endif 170 171void *memchr_inv(const void *s, int c, size_t n); 172char *strreplace(char *s, char old, char new); 173 174extern void kfree_const(const void *x); 175 176extern char *kstrdup(const char *s, gfp_t gfp) __malloc; 177extern const char *kstrdup_const(const char *s, gfp_t gfp); 178extern char *kstrndup(const char *s, size_t len, gfp_t gfp); 179extern void *kmemdup(const void *src, size_t len, gfp_t gfp); 180extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); 181 182extern char **argv_split(gfp_t gfp, const char *str, int *argcp); 183extern void argv_free(char **argv); 184 185extern bool sysfs_streq(const char *s1, const char *s2); 186int match_string(const char * const *array, size_t n, const char *string); 187int __sysfs_match_string(const char * const *array, size_t n, const char *s); 188 189/** 190 * sysfs_match_string - matches given string in an array 191 * @_a: array of strings 192 * @_s: string to match with 193 * 194 * Helper for __sysfs_match_string(). Calculates the size of @a automatically. 195 */ 196#define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s) 197 198#ifdef CONFIG_BINARY_PRINTF 199int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); 200int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf); 201int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4); 202#endif 203 204extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 205 const void *from, size_t available); 206 207int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); 208 209/** 210 * strstarts - does @str start with @prefix? 211 * @str: string to examine 212 * @prefix: prefix to look for. 213 */ 214static inline bool strstarts(const char *str, const char *prefix) 215{ 216 return strncmp(str, prefix, strlen(prefix)) == 0; 217} 218 219size_t memweight(const void *ptr, size_t bytes); 220 221/** 222 * memzero_explicit - Fill a region of memory (e.g. sensitive 223 * keying data) with 0s. 224 * @s: Pointer to the start of the area. 225 * @count: The size of the area. 226 * 227 * Note: usually using memset() is just fine (!), but in cases 228 * where clearing out _local_ data at the end of a scope is 229 * necessary, memzero_explicit() should be used instead in 230 * order to prevent the compiler from optimising away zeroing. 231 * 232 * memzero_explicit() doesn't need an arch-specific version as 233 * it just invokes the one of memset() implicitly. 234 */ 235static inline void memzero_explicit(void *s, size_t count) 236{ 237 memset(s, 0, count); 238 barrier_data(s); 239} 240 241/** 242 * kbasename - return the last part of a pathname. 243 * 244 * @path: path to extract the filename from. 245 */ 246static inline const char *kbasename(const char *path) 247{ 248 const char *tail = strrchr(path, '/'); 249 return tail ? tail + 1 : path; 250} 251 252#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE) 253#include <linux/fortify-string.h> 254#endif 255#ifndef unsafe_memcpy 256#define unsafe_memcpy(dst, src, bytes, justification) \ 257 memcpy(dst, src, bytes) 258#endif 259 260void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count, 261 int pad); 262 263/** 264 * memset_after - Set a value after a struct member to the end of a struct 265 * 266 * @obj: Address of target struct instance 267 * @v: Byte value to repeatedly write 268 * @member: after which struct member to start writing bytes 269 * 270 * This is good for clearing padding following the given member. 271 */ 272#define memset_after(obj, v, member) \ 273({ \ 274 u8 *__ptr = (u8 *)(obj); \ 275 typeof(v) __val = (v); \ 276 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \ 277 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \ 278}) 279 280/** 281 * memset_startat - Set a value starting at a member to the end of a struct 282 * 283 * @obj: Address of target struct instance 284 * @v: Byte value to repeatedly write 285 * @member: struct member to start writing at 286 * 287 * Note that if there is padding between the prior member and the target 288 * member, memset_after() should be used to clear the prior padding. 289 */ 290#define memset_startat(obj, v, member) \ 291({ \ 292 u8 *__ptr = (u8 *)(obj); \ 293 typeof(v) __val = (v); \ 294 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \ 295 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \ 296}) 297 298/** 299 * str_has_prefix - Test if a string has a given prefix 300 * @str: The string to test 301 * @prefix: The string to see if @str starts with 302 * 303 * A common way to test a prefix of a string is to do: 304 * strncmp(str, prefix, sizeof(prefix) - 1) 305 * 306 * But this can lead to bugs due to typos, or if prefix is a pointer 307 * and not a constant. Instead use str_has_prefix(). 308 * 309 * Returns: 310 * * strlen(@prefix) if @str starts with @prefix 311 * * 0 if @str does not start with @prefix 312 */ 313static __always_inline size_t str_has_prefix(const char *str, const char *prefix) 314{ 315 size_t len = strlen(prefix); 316 return strncmp(str, prefix, len) == 0 ? len : 0; 317} 318 319#endif /* _LINUX_STRING_H_ */