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