1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_STRING_H_ 3 #define _LINUX_STRING_H_ 4 5 #include <linux/args.h> 6 #include <linux/array_size.h> 7 #include <linux/compiler.h> /* for inline */ 8 #include <linux/types.h> /* for size_t */ 9 #include <linux/stddef.h> /* for NULL */ 10 #include <linux/err.h> /* for ERR_PTR() */ 11 #include <linux/errno.h> /* for E2BIG */ 12 #include <linux/overflow.h> /* for check_mul_overflow() */ 13 #include <linux/stdarg.h> 14 #include <uapi/linux/string.h> 15 16 extern char *strndup_user(const char __user *, long); 17 extern void *memdup_user(const void __user *, size_t); 18 extern void *vmemdup_user(const void __user *, size_t); 19 extern void *memdup_user_nul(const void __user *, size_t); 20 21 /** 22 * memdup_array_user - duplicate array from user space 23 * @src: source address in user space 24 * @n: number of array members to copy 25 * @size: size of one array member 26 * 27 * Return: an ERR_PTR() on failure. Result is physically 28 * contiguous, to be freed by kfree(). 29 */ 30 static inline void *memdup_array_user(const void __user *src, size_t n, size_t size) 31 { 32 size_t nbytes; 33 34 if (check_mul_overflow(n, size, &nbytes)) 35 return ERR_PTR(-EOVERFLOW); 36 37 return memdup_user(src, nbytes); 38 } 39 40 /** 41 * vmemdup_array_user - duplicate array from user space 42 * @src: source address in user space 43 * @n: number of array members to copy 44 * @size: size of one array member 45 * 46 * Return: an ERR_PTR() on failure. Result may be not 47 * physically contiguous. Use kvfree() to free. 48 */ 49 static inline void *vmemdup_array_user(const void __user *src, size_t n, size_t size) 50 { 51 size_t nbytes; 52 53 if (check_mul_overflow(n, size, &nbytes)) 54 return ERR_PTR(-EOVERFLOW); 55 56 return vmemdup_user(src, nbytes); 57 } 58 59 /* 60 * Include machine specific inline routines 61 */ 62 #include <asm/string.h> 63 64 #ifndef __HAVE_ARCH_STRCPY 65 extern char * strcpy(char *,const char *); 66 #endif 67 #ifndef __HAVE_ARCH_STRNCPY 68 extern char * strncpy(char *,const char *, __kernel_size_t); 69 #endif 70 ssize_t sized_strscpy(char *, const char *, size_t); 71 72 /* 73 * The 2 argument style can only be used when dst is an array with a 74 * known size. 75 */ 76 #define __strscpy0(dst, src, ...) \ 77 sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst)) 78 #define __strscpy1(dst, src, size) sized_strscpy(dst, src, size) 79 80 #define __strscpy_pad0(dst, src, ...) \ 81 sized_strscpy_pad(dst, src, sizeof(dst) + __must_be_array(dst)) 82 #define __strscpy_pad1(dst, src, size) sized_strscpy_pad(dst, src, size) 83 84 /** 85 * strscpy - Copy a C-string into a sized buffer 86 * @dst: Where to copy the string to 87 * @src: Where to copy the string from 88 * @...: Size of destination buffer (optional) 89 * 90 * Copy the source string @src, or as much of it as fits, into the 91 * destination @dst buffer. The behavior is undefined if the string 92 * buffers overlap. The destination @dst buffer is always NUL terminated, 93 * unless it's zero-sized. 94 * 95 * The size argument @... is only required when @dst is not an array, or 96 * when the copy needs to be smaller than sizeof(@dst). 97 * 98 * Preferred to strncpy() since it always returns a valid string, and 99 * doesn't unnecessarily force the tail of the destination buffer to be 100 * zero padded. If padding is desired please use strscpy_pad(). 101 * 102 * Returns the number of characters copied in @dst (not including the 103 * trailing %NUL) or -E2BIG if @size is 0 or the copy from @src was 104 * truncated. 105 */ 106 #define strscpy(dst, src, ...) \ 107 CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__) 108 109 #define sized_strscpy_pad(dest, src, count) ({ \ 110 char *__dst = (dest); \ 111 const char *__src = (src); \ 112 const size_t __count = (count); \ 113 ssize_t __wrote; \ 114 \ 115 __wrote = sized_strscpy(__dst, __src, __count); \ 116 if (__wrote >= 0 && __wrote < __count) \ 117 memset(__dst + __wrote + 1, 0, __count - __wrote - 1); \ 118 __wrote; \ 119 }) 120 121 /** 122 * strscpy_pad() - Copy a C-string into a sized buffer 123 * @dst: Where to copy the string to 124 * @src: Where to copy the string from 125 * @...: Size of destination buffer 126 * 127 * Copy the string, or as much of it as fits, into the dest buffer. The 128 * behavior is undefined if the string buffers overlap. The destination 129 * buffer is always %NUL terminated, unless it's zero-sized. 130 * 131 * If the source string is shorter than the destination buffer, the 132 * remaining bytes in the buffer will be filled with %NUL bytes. 133 * 134 * For full explanation of why you may want to consider using the 135 * 'strscpy' functions please see the function docstring for strscpy(). 136 * 137 * Returns: 138 * * The number of characters copied (not including the trailing %NULs) 139 * * -E2BIG if count is 0 or @src was truncated. 140 */ 141 #define strscpy_pad(dst, src, ...) \ 142 CONCATENATE(__strscpy_pad, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__) 143 144 #ifndef __HAVE_ARCH_STRCAT 145 extern char * strcat(char *, const char *); 146 #endif 147 #ifndef __HAVE_ARCH_STRNCAT 148 extern char * strncat(char *, const char *, __kernel_size_t); 149 #endif 150 #ifndef __HAVE_ARCH_STRLCAT 151 extern size_t strlcat(char *, const char *, __kernel_size_t); 152 #endif 153 #ifndef __HAVE_ARCH_STRCMP 154 extern int strcmp(const char *,const char *); 155 #endif 156 #ifndef __HAVE_ARCH_STRNCMP 157 extern int strncmp(const char *,const char *,__kernel_size_t); 158 #endif 159 #ifndef __HAVE_ARCH_STRCASECMP 160 extern int strcasecmp(const char *s1, const char *s2); 161 #endif 162 #ifndef __HAVE_ARCH_STRNCASECMP 163 extern int strncasecmp(const char *s1, const char *s2, size_t n); 164 #endif 165 #ifndef __HAVE_ARCH_STRCHR 166 extern char * strchr(const char *,int); 167 #endif 168 #ifndef __HAVE_ARCH_STRCHRNUL 169 extern char * strchrnul(const char *,int); 170 #endif 171 extern char * strnchrnul(const char *, size_t, int); 172 #ifndef __HAVE_ARCH_STRNCHR 173 extern char * strnchr(const char *, size_t, int); 174 #endif 175 #ifndef __HAVE_ARCH_STRRCHR 176 extern char * strrchr(const char *,int); 177 #endif 178 extern char * __must_check skip_spaces(const char *); 179 180 extern char *strim(char *); 181 182 static inline __must_check char *strstrip(char *str) 183 { 184 return strim(str); 185 } 186 187 #ifndef __HAVE_ARCH_STRSTR 188 extern char * strstr(const char *, const char *); 189 #endif 190 #ifndef __HAVE_ARCH_STRNSTR 191 extern char * strnstr(const char *, const char *, size_t); 192 #endif 193 #ifndef __HAVE_ARCH_STRLEN 194 extern __kernel_size_t strlen(const char *); 195 #endif 196 #ifndef __HAVE_ARCH_STRNLEN 197 extern __kernel_size_t strnlen(const char *,__kernel_size_t); 198 #endif 199 #ifndef __HAVE_ARCH_STRPBRK 200 extern char * strpbrk(const char *,const char *); 201 #endif 202 #ifndef __HAVE_ARCH_STRSEP 203 extern char * strsep(char **,const char *); 204 #endif 205 #ifndef __HAVE_ARCH_STRSPN 206 extern __kernel_size_t strspn(const char *,const char *); 207 #endif 208 #ifndef __HAVE_ARCH_STRCSPN 209 extern __kernel_size_t strcspn(const char *,const char *); 210 #endif 211 212 #ifndef __HAVE_ARCH_MEMSET 213 extern void * memset(void *,int,__kernel_size_t); 214 #endif 215 216 #ifndef __HAVE_ARCH_MEMSET16 217 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); 218 #endif 219 220 #ifndef __HAVE_ARCH_MEMSET32 221 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t); 222 #endif 223 224 #ifndef __HAVE_ARCH_MEMSET64 225 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t); 226 #endif 227 228 static inline void *memset_l(unsigned long *p, unsigned long v, 229 __kernel_size_t n) 230 { 231 if (BITS_PER_LONG == 32) 232 return memset32((uint32_t *)p, v, n); 233 else 234 return memset64((uint64_t *)p, v, n); 235 } 236 237 static inline void *memset_p(void **p, void *v, __kernel_size_t n) 238 { 239 if (BITS_PER_LONG == 32) 240 return memset32((uint32_t *)p, (uintptr_t)v, n); 241 else 242 return memset64((uint64_t *)p, (uintptr_t)v, n); 243 } 244 245 extern void **__memcat_p(void **a, void **b); 246 #define memcat_p(a, b) ({ \ 247 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \ 248 "type mismatch in memcat_p()"); \ 249 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \ 250 }) 251 252 #ifndef __HAVE_ARCH_MEMCPY 253 extern void * memcpy(void *,const void *,__kernel_size_t); 254 #endif 255 #ifndef __HAVE_ARCH_MEMMOVE 256 extern void * memmove(void *,const void *,__kernel_size_t); 257 #endif 258 #ifndef __HAVE_ARCH_MEMSCAN 259 extern void * memscan(void *,int,__kernel_size_t); 260 #endif 261 #ifndef __HAVE_ARCH_MEMCMP 262 extern int memcmp(const void *,const void *,__kernel_size_t); 263 #endif 264 #ifndef __HAVE_ARCH_BCMP 265 extern int bcmp(const void *,const void *,__kernel_size_t); 266 #endif 267 #ifndef __HAVE_ARCH_MEMCHR 268 extern void * memchr(const void *,int,__kernel_size_t); 269 #endif 270 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE 271 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) 272 { 273 memcpy(dst, src, cnt); 274 } 275 #endif 276 277 void *memchr_inv(const void *s, int c, size_t n); 278 char *strreplace(char *str, char old, char new); 279 280 extern void kfree_const(const void *x); 281 282 extern char *kstrdup(const char *s, gfp_t gfp) __malloc; 283 extern const char *kstrdup_const(const char *s, gfp_t gfp); 284 extern char *kstrndup(const char *s, size_t len, gfp_t gfp); 285 extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 286 extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 287 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); 288 289 extern char **argv_split(gfp_t gfp, const char *str, int *argcp); 290 extern void argv_free(char **argv); 291 292 extern bool sysfs_streq(const char *s1, const char *s2); 293 int match_string(const char * const *array, size_t n, const char *string); 294 int __sysfs_match_string(const char * const *array, size_t n, const char *s); 295 296 /** 297 * sysfs_match_string - matches given string in an array 298 * @_a: array of strings 299 * @_s: string to match with 300 * 301 * Helper for __sysfs_match_string(). Calculates the size of @a automatically. 302 */ 303 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s) 304 305 #ifdef CONFIG_BINARY_PRINTF 306 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); 307 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf); 308 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4); 309 #endif 310 311 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 312 const void *from, size_t available); 313 314 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); 315 316 /** 317 * strstarts - does @str start with @prefix? 318 * @str: string to examine 319 * @prefix: prefix to look for. 320 */ 321 static inline bool strstarts(const char *str, const char *prefix) 322 { 323 return strncmp(str, prefix, strlen(prefix)) == 0; 324 } 325 326 size_t memweight(const void *ptr, size_t bytes); 327 328 /** 329 * memzero_explicit - Fill a region of memory (e.g. sensitive 330 * keying data) with 0s. 331 * @s: Pointer to the start of the area. 332 * @count: The size of the area. 333 * 334 * Note: usually using memset() is just fine (!), but in cases 335 * where clearing out _local_ data at the end of a scope is 336 * necessary, memzero_explicit() should be used instead in 337 * order to prevent the compiler from optimising away zeroing. 338 * 339 * memzero_explicit() doesn't need an arch-specific version as 340 * it just invokes the one of memset() implicitly. 341 */ 342 static inline void memzero_explicit(void *s, size_t count) 343 { 344 memset(s, 0, count); 345 barrier_data(s); 346 } 347 348 /** 349 * kbasename - return the last part of a pathname. 350 * 351 * @path: path to extract the filename from. 352 */ 353 static inline const char *kbasename(const char *path) 354 { 355 const char *tail = strrchr(path, '/'); 356 return tail ? tail + 1 : path; 357 } 358 359 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE) 360 #include <linux/fortify-string.h> 361 #endif 362 #ifndef unsafe_memcpy 363 #define unsafe_memcpy(dst, src, bytes, justification) \ 364 memcpy(dst, src, bytes) 365 #endif 366 367 void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count, 368 int pad); 369 370 /** 371 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer 372 * 373 * @dest: Pointer of destination character array (marked as __nonstring) 374 * @src: Pointer to NUL-terminated string 375 * @pad: Padding character to fill any remaining bytes of @dest after copy 376 * 377 * This is a replacement for strncpy() uses where the destination is not 378 * a NUL-terminated string, but with bounds checking on the source size, and 379 * an explicit padding character. If padding is not required, use strtomem(). 380 * 381 * Note that the size of @dest is not an argument, as the length of @dest 382 * must be discoverable by the compiler. 383 */ 384 #define strtomem_pad(dest, src, pad) do { \ 385 const size_t _dest_len = __builtin_object_size(dest, 1); \ 386 const size_t _src_len = __builtin_object_size(src, 1); \ 387 \ 388 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 389 _dest_len == (size_t)-1); \ 390 memcpy_and_pad(dest, _dest_len, src, \ 391 strnlen(src, min(_src_len, _dest_len)), pad); \ 392 } while (0) 393 394 /** 395 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer 396 * 397 * @dest: Pointer of destination character array (marked as __nonstring) 398 * @src: Pointer to NUL-terminated string 399 * 400 * This is a replacement for strncpy() uses where the destination is not 401 * a NUL-terminated string, but with bounds checking on the source size, and 402 * without trailing padding. If padding is required, use strtomem_pad(). 403 * 404 * Note that the size of @dest is not an argument, as the length of @dest 405 * must be discoverable by the compiler. 406 */ 407 #define strtomem(dest, src) do { \ 408 const size_t _dest_len = __builtin_object_size(dest, 1); \ 409 const size_t _src_len = __builtin_object_size(src, 1); \ 410 \ 411 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 412 _dest_len == (size_t)-1); \ 413 memcpy(dest, src, strnlen(src, min(_src_len, _dest_len))); \ 414 } while (0) 415 416 /** 417 * memset_after - Set a value after a struct member to the end of a struct 418 * 419 * @obj: Address of target struct instance 420 * @v: Byte value to repeatedly write 421 * @member: after which struct member to start writing bytes 422 * 423 * This is good for clearing padding following the given member. 424 */ 425 #define memset_after(obj, v, member) \ 426 ({ \ 427 u8 *__ptr = (u8 *)(obj); \ 428 typeof(v) __val = (v); \ 429 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \ 430 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \ 431 }) 432 433 /** 434 * memset_startat - Set a value starting at a member to the end of a struct 435 * 436 * @obj: Address of target struct instance 437 * @v: Byte value to repeatedly write 438 * @member: struct member to start writing at 439 * 440 * Note that if there is padding between the prior member and the target 441 * member, memset_after() should be used to clear the prior padding. 442 */ 443 #define memset_startat(obj, v, member) \ 444 ({ \ 445 u8 *__ptr = (u8 *)(obj); \ 446 typeof(v) __val = (v); \ 447 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \ 448 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \ 449 }) 450 451 /** 452 * str_has_prefix - Test if a string has a given prefix 453 * @str: The string to test 454 * @prefix: The string to see if @str starts with 455 * 456 * A common way to test a prefix of a string is to do: 457 * strncmp(str, prefix, sizeof(prefix) - 1) 458 * 459 * But this can lead to bugs due to typos, or if prefix is a pointer 460 * and not a constant. Instead use str_has_prefix(). 461 * 462 * Returns: 463 * * strlen(@prefix) if @str starts with @prefix 464 * * 0 if @str does not start with @prefix 465 */ 466 static __always_inline size_t str_has_prefix(const char *str, const char *prefix) 467 { 468 size_t len = strlen(prefix); 469 return strncmp(str, prefix, len) == 0 ? len : 0; 470 } 471 472 #endif /* _LINUX_STRING_H_ */ 473