1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_STRING_H_ 3 #define _LINUX_STRING_H_ 4 5 #include <linux/array_size.h> 6 #include <linux/compiler.h> /* for inline */ 7 #include <linux/types.h> /* for size_t */ 8 #include <linux/stddef.h> /* for NULL */ 9 #include <linux/err.h> /* for ERR_PTR() */ 10 #include <linux/errno.h> /* for E2BIG */ 11 #include <linux/overflow.h> /* for check_mul_overflow() */ 12 #include <linux/stdarg.h> 13 #include <uapi/linux/string.h> 14 15 extern char *strndup_user(const char __user *, long); 16 extern void *memdup_user(const void __user *, size_t); 17 extern void *vmemdup_user(const void __user *, size_t); 18 extern void *memdup_user_nul(const void __user *, size_t); 19 20 /** 21 * memdup_array_user - duplicate array from user space 22 * @src: source address in user space 23 * @n: number of array members to copy 24 * @size: size of one array member 25 * 26 * Return: an ERR_PTR() on failure. Result is physically 27 * contiguous, to be freed by kfree(). 28 */ 29 static inline void *memdup_array_user(const void __user *src, size_t n, size_t size) 30 { 31 size_t nbytes; 32 33 if (check_mul_overflow(n, size, &nbytes)) 34 return ERR_PTR(-EOVERFLOW); 35 36 return memdup_user(src, nbytes); 37 } 38 39 /** 40 * vmemdup_array_user - duplicate array from user space 41 * @src: source address in user space 42 * @n: number of array members to copy 43 * @size: size of one array member 44 * 45 * Return: an ERR_PTR() on failure. Result may be not 46 * physically contiguous. Use kvfree() to free. 47 */ 48 static inline void *vmemdup_array_user(const void __user *src, size_t n, size_t size) 49 { 50 size_t nbytes; 51 52 if (check_mul_overflow(n, size, &nbytes)) 53 return ERR_PTR(-EOVERFLOW); 54 55 return vmemdup_user(src, nbytes); 56 } 57 58 /* 59 * Include machine specific inline routines 60 */ 61 #include <asm/string.h> 62 63 #ifndef __HAVE_ARCH_STRCPY 64 extern char * strcpy(char *,const char *); 65 #endif 66 #ifndef __HAVE_ARCH_STRNCPY 67 extern char * strncpy(char *,const char *, __kernel_size_t); 68 #endif 69 #ifndef __HAVE_ARCH_STRLCPY 70 size_t strlcpy(char *, const char *, size_t); 71 #endif 72 #ifndef __HAVE_ARCH_STRSCPY 73 ssize_t strscpy(char *, const char *, size_t); 74 #endif 75 76 /* Wraps calls to strscpy()/memset(), no arch specific code required */ 77 ssize_t strscpy_pad(char *dest, const char *src, size_t count); 78 79 #ifndef __HAVE_ARCH_STRCAT 80 extern char * strcat(char *, const char *); 81 #endif 82 #ifndef __HAVE_ARCH_STRNCAT 83 extern char * strncat(char *, const char *, __kernel_size_t); 84 #endif 85 #ifndef __HAVE_ARCH_STRLCAT 86 extern size_t strlcat(char *, const char *, __kernel_size_t); 87 #endif 88 #ifndef __HAVE_ARCH_STRCMP 89 extern int strcmp(const char *,const char *); 90 #endif 91 #ifndef __HAVE_ARCH_STRNCMP 92 extern int strncmp(const char *,const char *,__kernel_size_t); 93 #endif 94 #ifndef __HAVE_ARCH_STRCASECMP 95 extern int strcasecmp(const char *s1, const char *s2); 96 #endif 97 #ifndef __HAVE_ARCH_STRNCASECMP 98 extern int strncasecmp(const char *s1, const char *s2, size_t n); 99 #endif 100 #ifndef __HAVE_ARCH_STRCHR 101 extern char * strchr(const char *,int); 102 #endif 103 #ifndef __HAVE_ARCH_STRCHRNUL 104 extern char * strchrnul(const char *,int); 105 #endif 106 extern char * strnchrnul(const char *, size_t, int); 107 #ifndef __HAVE_ARCH_STRNCHR 108 extern char * strnchr(const char *, size_t, int); 109 #endif 110 #ifndef __HAVE_ARCH_STRRCHR 111 extern char * strrchr(const char *,int); 112 #endif 113 extern char * __must_check skip_spaces(const char *); 114 115 extern char *strim(char *); 116 117 static inline __must_check char *strstrip(char *str) 118 { 119 return strim(str); 120 } 121 122 #ifndef __HAVE_ARCH_STRSTR 123 extern char * strstr(const char *, const char *); 124 #endif 125 #ifndef __HAVE_ARCH_STRNSTR 126 extern char * strnstr(const char *, const char *, size_t); 127 #endif 128 #ifndef __HAVE_ARCH_STRLEN 129 extern __kernel_size_t strlen(const char *); 130 #endif 131 #ifndef __HAVE_ARCH_STRNLEN 132 extern __kernel_size_t strnlen(const char *,__kernel_size_t); 133 #endif 134 #ifndef __HAVE_ARCH_STRPBRK 135 extern char * strpbrk(const char *,const char *); 136 #endif 137 #ifndef __HAVE_ARCH_STRSEP 138 extern char * strsep(char **,const char *); 139 #endif 140 #ifndef __HAVE_ARCH_STRSPN 141 extern __kernel_size_t strspn(const char *,const char *); 142 #endif 143 #ifndef __HAVE_ARCH_STRCSPN 144 extern __kernel_size_t strcspn(const char *,const char *); 145 #endif 146 147 #ifndef __HAVE_ARCH_MEMSET 148 extern void * memset(void *,int,__kernel_size_t); 149 #endif 150 151 #ifndef __HAVE_ARCH_MEMSET16 152 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); 153 #endif 154 155 #ifndef __HAVE_ARCH_MEMSET32 156 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t); 157 #endif 158 159 #ifndef __HAVE_ARCH_MEMSET64 160 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t); 161 #endif 162 163 static inline void *memset_l(unsigned long *p, unsigned long v, 164 __kernel_size_t n) 165 { 166 if (BITS_PER_LONG == 32) 167 return memset32((uint32_t *)p, v, n); 168 else 169 return memset64((uint64_t *)p, v, n); 170 } 171 172 static inline void *memset_p(void **p, void *v, __kernel_size_t n) 173 { 174 if (BITS_PER_LONG == 32) 175 return memset32((uint32_t *)p, (uintptr_t)v, n); 176 else 177 return memset64((uint64_t *)p, (uintptr_t)v, n); 178 } 179 180 extern void **__memcat_p(void **a, void **b); 181 #define memcat_p(a, b) ({ \ 182 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \ 183 "type mismatch in memcat_p()"); \ 184 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \ 185 }) 186 187 #ifndef __HAVE_ARCH_MEMCPY 188 extern void * memcpy(void *,const void *,__kernel_size_t); 189 #endif 190 #ifndef __HAVE_ARCH_MEMMOVE 191 extern void * memmove(void *,const void *,__kernel_size_t); 192 #endif 193 #ifndef __HAVE_ARCH_MEMSCAN 194 extern void * memscan(void *,int,__kernel_size_t); 195 #endif 196 #ifndef __HAVE_ARCH_MEMCMP 197 extern int memcmp(const void *,const void *,__kernel_size_t); 198 #endif 199 #ifndef __HAVE_ARCH_BCMP 200 extern int bcmp(const void *,const void *,__kernel_size_t); 201 #endif 202 #ifndef __HAVE_ARCH_MEMCHR 203 extern void * memchr(const void *,int,__kernel_size_t); 204 #endif 205 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE 206 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) 207 { 208 memcpy(dst, src, cnt); 209 } 210 #endif 211 212 void *memchr_inv(const void *s, int c, size_t n); 213 char *strreplace(char *str, char old, char new); 214 215 extern void kfree_const(const void *x); 216 217 extern char *kstrdup(const char *s, gfp_t gfp) __malloc; 218 extern const char *kstrdup_const(const char *s, gfp_t gfp); 219 extern char *kstrndup(const char *s, size_t len, gfp_t gfp); 220 extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 221 extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 222 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); 223 224 extern char **argv_split(gfp_t gfp, const char *str, int *argcp); 225 extern void argv_free(char **argv); 226 227 extern bool sysfs_streq(const char *s1, const char *s2); 228 int match_string(const char * const *array, size_t n, const char *string); 229 int __sysfs_match_string(const char * const *array, size_t n, const char *s); 230 231 /** 232 * sysfs_match_string - matches given string in an array 233 * @_a: array of strings 234 * @_s: string to match with 235 * 236 * Helper for __sysfs_match_string(). Calculates the size of @a automatically. 237 */ 238 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s) 239 240 #ifdef CONFIG_BINARY_PRINTF 241 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); 242 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf); 243 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4); 244 #endif 245 246 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 247 const void *from, size_t available); 248 249 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); 250 251 /** 252 * strstarts - does @str start with @prefix? 253 * @str: string to examine 254 * @prefix: prefix to look for. 255 */ 256 static inline bool strstarts(const char *str, const char *prefix) 257 { 258 return strncmp(str, prefix, strlen(prefix)) == 0; 259 } 260 261 size_t memweight(const void *ptr, size_t bytes); 262 263 /** 264 * memzero_explicit - Fill a region of memory (e.g. sensitive 265 * keying data) with 0s. 266 * @s: Pointer to the start of the area. 267 * @count: The size of the area. 268 * 269 * Note: usually using memset() is just fine (!), but in cases 270 * where clearing out _local_ data at the end of a scope is 271 * necessary, memzero_explicit() should be used instead in 272 * order to prevent the compiler from optimising away zeroing. 273 * 274 * memzero_explicit() doesn't need an arch-specific version as 275 * it just invokes the one of memset() implicitly. 276 */ 277 static inline void memzero_explicit(void *s, size_t count) 278 { 279 memset(s, 0, count); 280 barrier_data(s); 281 } 282 283 /** 284 * kbasename - return the last part of a pathname. 285 * 286 * @path: path to extract the filename from. 287 */ 288 static inline const char *kbasename(const char *path) 289 { 290 const char *tail = strrchr(path, '/'); 291 return tail ? tail + 1 : path; 292 } 293 294 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE) 295 #include <linux/fortify-string.h> 296 #endif 297 #ifndef unsafe_memcpy 298 #define unsafe_memcpy(dst, src, bytes, justification) \ 299 memcpy(dst, src, bytes) 300 #endif 301 302 void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count, 303 int pad); 304 305 /** 306 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer 307 * 308 * @dest: Pointer of destination character array (marked as __nonstring) 309 * @src: Pointer to NUL-terminated string 310 * @pad: Padding character to fill any remaining bytes of @dest after copy 311 * 312 * This is a replacement for strncpy() uses where the destination is not 313 * a NUL-terminated string, but with bounds checking on the source size, and 314 * an explicit padding character. If padding is not required, use strtomem(). 315 * 316 * Note that the size of @dest is not an argument, as the length of @dest 317 * must be discoverable by the compiler. 318 */ 319 #define strtomem_pad(dest, src, pad) do { \ 320 const size_t _dest_len = __builtin_object_size(dest, 1); \ 321 const size_t _src_len = __builtin_object_size(src, 1); \ 322 \ 323 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 324 _dest_len == (size_t)-1); \ 325 memcpy_and_pad(dest, _dest_len, src, \ 326 strnlen(src, min(_src_len, _dest_len)), pad); \ 327 } while (0) 328 329 /** 330 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer 331 * 332 * @dest: Pointer of destination character array (marked as __nonstring) 333 * @src: Pointer to NUL-terminated string 334 * 335 * This is a replacement for strncpy() uses where the destination is not 336 * a NUL-terminated string, but with bounds checking on the source size, and 337 * without trailing padding. If padding is required, use strtomem_pad(). 338 * 339 * Note that the size of @dest is not an argument, as the length of @dest 340 * must be discoverable by the compiler. 341 */ 342 #define strtomem(dest, src) do { \ 343 const size_t _dest_len = __builtin_object_size(dest, 1); \ 344 const size_t _src_len = __builtin_object_size(src, 1); \ 345 \ 346 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 347 _dest_len == (size_t)-1); \ 348 memcpy(dest, src, strnlen(src, min(_src_len, _dest_len))); \ 349 } while (0) 350 351 /** 352 * memset_after - Set a value after a struct member to the end of a struct 353 * 354 * @obj: Address of target struct instance 355 * @v: Byte value to repeatedly write 356 * @member: after which struct member to start writing bytes 357 * 358 * This is good for clearing padding following the given member. 359 */ 360 #define memset_after(obj, v, member) \ 361 ({ \ 362 u8 *__ptr = (u8 *)(obj); \ 363 typeof(v) __val = (v); \ 364 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \ 365 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \ 366 }) 367 368 /** 369 * memset_startat - Set a value starting at a member to the end of a struct 370 * 371 * @obj: Address of target struct instance 372 * @v: Byte value to repeatedly write 373 * @member: struct member to start writing at 374 * 375 * Note that if there is padding between the prior member and the target 376 * member, memset_after() should be used to clear the prior padding. 377 */ 378 #define memset_startat(obj, v, member) \ 379 ({ \ 380 u8 *__ptr = (u8 *)(obj); \ 381 typeof(v) __val = (v); \ 382 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \ 383 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \ 384 }) 385 386 /** 387 * str_has_prefix - Test if a string has a given prefix 388 * @str: The string to test 389 * @prefix: The string to see if @str starts with 390 * 391 * A common way to test a prefix of a string is to do: 392 * strncmp(str, prefix, sizeof(prefix) - 1) 393 * 394 * But this can lead to bugs due to typos, or if prefix is a pointer 395 * and not a constant. Instead use str_has_prefix(). 396 * 397 * Returns: 398 * * strlen(@prefix) if @str starts with @prefix 399 * * 0 if @str does not start with @prefix 400 */ 401 static __always_inline size_t str_has_prefix(const char *str, const char *prefix) 402 { 403 size_t len = strlen(prefix); 404 return strncmp(str, prefix, len) == 0 ? len : 0; 405 } 406 407 #endif /* _LINUX_STRING_H_ */ 408