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) __realloc_size(2); 18 extern void *vmemdup_user(const void __user *, size_t) __realloc_size(2); 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 __realloc_size(2, 3) 31 void *memdup_array_user(const void __user *src, size_t n, size_t size) 32 { 33 size_t nbytes; 34 35 if (check_mul_overflow(n, size, &nbytes)) 36 return ERR_PTR(-EOVERFLOW); 37 38 return memdup_user(src, nbytes); 39 } 40 41 /** 42 * vmemdup_array_user - duplicate array from user space 43 * @src: source address in user space 44 * @n: number of array members to copy 45 * @size: size of one array member 46 * 47 * Return: an ERR_PTR() on failure. Result may be not 48 * physically contiguous. Use kvfree() to free. 49 */ 50 static inline __realloc_size(2, 3) 51 void *vmemdup_array_user(const void __user *src, size_t n, size_t size) 52 { 53 size_t nbytes; 54 55 if (check_mul_overflow(n, size, &nbytes)) 56 return ERR_PTR(-EOVERFLOW); 57 58 return vmemdup_user(src, nbytes); 59 } 60 61 /* 62 * Include machine specific inline routines 63 */ 64 #include <asm/string.h> 65 66 #ifndef __HAVE_ARCH_STRCPY 67 extern char * strcpy(char *,const char *); 68 #endif 69 #ifndef __HAVE_ARCH_STRNCPY 70 extern char * strncpy(char *,const char *, __kernel_size_t); 71 #endif 72 ssize_t sized_strscpy(char *, const char *, size_t); 73 74 /* 75 * The 2 argument style can only be used when dst is an array with a 76 * known size. 77 */ 78 #define __strscpy0(dst, src, ...) \ 79 sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst)) 80 #define __strscpy1(dst, src, size) sized_strscpy(dst, src, size) 81 82 #define __strscpy_pad0(dst, src, ...) \ 83 sized_strscpy_pad(dst, src, sizeof(dst) + __must_be_array(dst)) 84 #define __strscpy_pad1(dst, src, size) sized_strscpy_pad(dst, src, size) 85 86 /** 87 * strscpy - Copy a C-string into a sized buffer 88 * @dst: Where to copy the string to 89 * @src: Where to copy the string from 90 * @...: Size of destination buffer (optional) 91 * 92 * Copy the source string @src, or as much of it as fits, into the 93 * destination @dst buffer. The behavior is undefined if the string 94 * buffers overlap. The destination @dst buffer is always NUL terminated, 95 * unless it's zero-sized. 96 * 97 * The size argument @... is only required when @dst is not an array, or 98 * when the copy needs to be smaller than sizeof(@dst). 99 * 100 * Preferred to strncpy() since it always returns a valid string, and 101 * doesn't unnecessarily force the tail of the destination buffer to be 102 * zero padded. If padding is desired please use strscpy_pad(). 103 * 104 * Returns the number of characters copied in @dst (not including the 105 * trailing %NUL) or -E2BIG if @size is 0 or the copy from @src was 106 * truncated. 107 */ 108 #define strscpy(dst, src, ...) \ 109 CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__) 110 111 #define sized_strscpy_pad(dest, src, count) ({ \ 112 char *__dst = (dest); \ 113 const char *__src = (src); \ 114 const size_t __count = (count); \ 115 ssize_t __wrote; \ 116 \ 117 __wrote = sized_strscpy(__dst, __src, __count); \ 118 if (__wrote >= 0 && __wrote < __count) \ 119 memset(__dst + __wrote + 1, 0, __count - __wrote - 1); \ 120 __wrote; \ 121 }) 122 123 /** 124 * strscpy_pad() - Copy a C-string into a sized buffer 125 * @dst: Where to copy the string to 126 * @src: Where to copy the string from 127 * @...: Size of destination buffer 128 * 129 * Copy the string, or as much of it as fits, into the dest buffer. The 130 * behavior is undefined if the string buffers overlap. The destination 131 * buffer is always %NUL terminated, unless it's zero-sized. 132 * 133 * If the source string is shorter than the destination buffer, the 134 * remaining bytes in the buffer will be filled with %NUL bytes. 135 * 136 * For full explanation of why you may want to consider using the 137 * 'strscpy' functions please see the function docstring for strscpy(). 138 * 139 * Returns: 140 * * The number of characters copied (not including the trailing %NULs) 141 * * -E2BIG if count is 0 or @src was truncated. 142 */ 143 #define strscpy_pad(dst, src, ...) \ 144 CONCATENATE(__strscpy_pad, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__) 145 146 #ifndef __HAVE_ARCH_STRCAT 147 extern char * strcat(char *, const char *); 148 #endif 149 #ifndef __HAVE_ARCH_STRNCAT 150 extern char * strncat(char *, const char *, __kernel_size_t); 151 #endif 152 #ifndef __HAVE_ARCH_STRLCAT 153 extern size_t strlcat(char *, const char *, __kernel_size_t); 154 #endif 155 #ifndef __HAVE_ARCH_STRCMP 156 extern int strcmp(const char *,const char *); 157 #endif 158 #ifndef __HAVE_ARCH_STRNCMP 159 extern int strncmp(const char *,const char *,__kernel_size_t); 160 #endif 161 #ifndef __HAVE_ARCH_STRCASECMP 162 extern int strcasecmp(const char *s1, const char *s2); 163 #endif 164 #ifndef __HAVE_ARCH_STRNCASECMP 165 extern int strncasecmp(const char *s1, const char *s2, size_t n); 166 #endif 167 #ifndef __HAVE_ARCH_STRCHR 168 extern char * strchr(const char *,int); 169 #endif 170 #ifndef __HAVE_ARCH_STRCHRNUL 171 extern char * strchrnul(const char *,int); 172 #endif 173 extern char * strnchrnul(const char *, size_t, int); 174 #ifndef __HAVE_ARCH_STRNCHR 175 extern char * strnchr(const char *, size_t, int); 176 #endif 177 #ifndef __HAVE_ARCH_STRRCHR 178 extern char * strrchr(const char *,int); 179 #endif 180 extern char * __must_check skip_spaces(const char *); 181 182 extern char *strim(char *); 183 184 static inline __must_check char *strstrip(char *str) 185 { 186 return strim(str); 187 } 188 189 #ifndef __HAVE_ARCH_STRSTR 190 extern char * strstr(const char *, const char *); 191 #endif 192 #ifndef __HAVE_ARCH_STRNSTR 193 extern char * strnstr(const char *, const char *, size_t); 194 #endif 195 #ifndef __HAVE_ARCH_STRLEN 196 extern __kernel_size_t strlen(const char *); 197 #endif 198 #ifndef __HAVE_ARCH_STRNLEN 199 extern __kernel_size_t strnlen(const char *,__kernel_size_t); 200 #endif 201 #ifndef __HAVE_ARCH_STRPBRK 202 extern char * strpbrk(const char *,const char *); 203 #endif 204 #ifndef __HAVE_ARCH_STRSEP 205 extern char * strsep(char **,const char *); 206 #endif 207 #ifndef __HAVE_ARCH_STRSPN 208 extern __kernel_size_t strspn(const char *,const char *); 209 #endif 210 #ifndef __HAVE_ARCH_STRCSPN 211 extern __kernel_size_t strcspn(const char *,const char *); 212 #endif 213 214 #ifndef __HAVE_ARCH_MEMSET 215 extern void * memset(void *,int,__kernel_size_t); 216 #endif 217 218 #ifndef __HAVE_ARCH_MEMSET16 219 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); 220 #endif 221 222 #ifndef __HAVE_ARCH_MEMSET32 223 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t); 224 #endif 225 226 #ifndef __HAVE_ARCH_MEMSET64 227 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t); 228 #endif 229 230 static inline void *memset_l(unsigned long *p, unsigned long v, 231 __kernel_size_t n) 232 { 233 if (BITS_PER_LONG == 32) 234 return memset32((uint32_t *)p, v, n); 235 else 236 return memset64((uint64_t *)p, v, n); 237 } 238 239 static inline void *memset_p(void **p, void *v, __kernel_size_t n) 240 { 241 if (BITS_PER_LONG == 32) 242 return memset32((uint32_t *)p, (uintptr_t)v, n); 243 else 244 return memset64((uint64_t *)p, (uintptr_t)v, n); 245 } 246 247 extern void **__memcat_p(void **a, void **b); 248 #define memcat_p(a, b) ({ \ 249 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \ 250 "type mismatch in memcat_p()"); \ 251 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \ 252 }) 253 254 #ifndef __HAVE_ARCH_MEMCPY 255 extern void * memcpy(void *,const void *,__kernel_size_t); 256 #endif 257 #ifndef __HAVE_ARCH_MEMMOVE 258 extern void * memmove(void *,const void *,__kernel_size_t); 259 #endif 260 #ifndef __HAVE_ARCH_MEMSCAN 261 extern void * memscan(void *,int,__kernel_size_t); 262 #endif 263 #ifndef __HAVE_ARCH_MEMCMP 264 extern int memcmp(const void *,const void *,__kernel_size_t); 265 #endif 266 #ifndef __HAVE_ARCH_BCMP 267 extern int bcmp(const void *,const void *,__kernel_size_t); 268 #endif 269 #ifndef __HAVE_ARCH_MEMCHR 270 extern void * memchr(const void *,int,__kernel_size_t); 271 #endif 272 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE 273 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) 274 { 275 memcpy(dst, src, cnt); 276 } 277 #endif 278 279 void *memchr_inv(const void *s, int c, size_t n); 280 char *strreplace(char *str, char old, char new); 281 282 extern void kfree_const(const void *x); 283 284 extern char *kstrdup(const char *s, gfp_t gfp) __malloc; 285 extern const char *kstrdup_const(const char *s, gfp_t gfp); 286 extern char *kstrndup(const char *s, size_t len, gfp_t gfp); 287 extern void *kmemdup_noprof(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 288 #define kmemdup(...) alloc_hooks(kmemdup_noprof(__VA_ARGS__)) 289 290 extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 291 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); 292 extern void *kmemdup_array(const void *src, size_t element_size, size_t count, gfp_t gfp) 293 __realloc_size(2, 3); 294 295 /* lib/argv_split.c */ 296 extern char **argv_split(gfp_t gfp, const char *str, int *argcp); 297 extern void argv_free(char **argv); 298 299 /* lib/cmdline.c */ 300 extern int get_option(char **str, int *pint); 301 extern char *get_options(const char *str, int nints, int *ints); 302 extern unsigned long long memparse(const char *ptr, char **retptr); 303 extern bool parse_option_str(const char *str, const char *option); 304 extern char *next_arg(char *args, char **param, char **val); 305 306 extern bool sysfs_streq(const char *s1, const char *s2); 307 int match_string(const char * const *array, size_t n, const char *string); 308 int __sysfs_match_string(const char * const *array, size_t n, const char *s); 309 310 /** 311 * sysfs_match_string - matches given string in an array 312 * @_a: array of strings 313 * @_s: string to match with 314 * 315 * Helper for __sysfs_match_string(). Calculates the size of @a automatically. 316 */ 317 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s) 318 319 #ifdef CONFIG_BINARY_PRINTF 320 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); 321 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf); 322 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4); 323 #endif 324 325 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 326 const void *from, size_t available); 327 328 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); 329 330 /** 331 * strstarts - does @str start with @prefix? 332 * @str: string to examine 333 * @prefix: prefix to look for. 334 */ 335 static inline bool strstarts(const char *str, const char *prefix) 336 { 337 return strncmp(str, prefix, strlen(prefix)) == 0; 338 } 339 340 size_t memweight(const void *ptr, size_t bytes); 341 342 /** 343 * memzero_explicit - Fill a region of memory (e.g. sensitive 344 * keying data) with 0s. 345 * @s: Pointer to the start of the area. 346 * @count: The size of the area. 347 * 348 * Note: usually using memset() is just fine (!), but in cases 349 * where clearing out _local_ data at the end of a scope is 350 * necessary, memzero_explicit() should be used instead in 351 * order to prevent the compiler from optimising away zeroing. 352 * 353 * memzero_explicit() doesn't need an arch-specific version as 354 * it just invokes the one of memset() implicitly. 355 */ 356 static inline void memzero_explicit(void *s, size_t count) 357 { 358 memset(s, 0, count); 359 barrier_data(s); 360 } 361 362 /** 363 * kbasename - return the last part of a pathname. 364 * 365 * @path: path to extract the filename from. 366 */ 367 static inline const char *kbasename(const char *path) 368 { 369 const char *tail = strrchr(path, '/'); 370 return tail ? tail + 1 : path; 371 } 372 373 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE) 374 #include <linux/fortify-string.h> 375 #endif 376 #ifndef unsafe_memcpy 377 #define unsafe_memcpy(dst, src, bytes, justification) \ 378 memcpy(dst, src, bytes) 379 #endif 380 381 void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count, 382 int pad); 383 384 /** 385 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer 386 * 387 * @dest: Pointer of destination character array (marked as __nonstring) 388 * @src: Pointer to NUL-terminated string 389 * @pad: Padding character to fill any remaining bytes of @dest after copy 390 * 391 * This is a replacement for strncpy() uses where the destination is not 392 * a NUL-terminated string, but with bounds checking on the source size, and 393 * an explicit padding character. If padding is not required, use strtomem(). 394 * 395 * Note that the size of @dest is not an argument, as the length of @dest 396 * must be discoverable by the compiler. 397 */ 398 #define strtomem_pad(dest, src, pad) do { \ 399 const size_t _dest_len = __builtin_object_size(dest, 1); \ 400 const size_t _src_len = __builtin_object_size(src, 1); \ 401 \ 402 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 403 _dest_len == (size_t)-1); \ 404 memcpy_and_pad(dest, _dest_len, src, \ 405 strnlen(src, min(_src_len, _dest_len)), pad); \ 406 } while (0) 407 408 /** 409 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer 410 * 411 * @dest: Pointer of destination character array (marked as __nonstring) 412 * @src: Pointer to NUL-terminated string 413 * 414 * This is a replacement for strncpy() uses where the destination is not 415 * a NUL-terminated string, but with bounds checking on the source size, and 416 * without trailing padding. If padding is required, use strtomem_pad(). 417 * 418 * Note that the size of @dest is not an argument, as the length of @dest 419 * must be discoverable by the compiler. 420 */ 421 #define strtomem(dest, src) do { \ 422 const size_t _dest_len = __builtin_object_size(dest, 1); \ 423 const size_t _src_len = __builtin_object_size(src, 1); \ 424 \ 425 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 426 _dest_len == (size_t)-1); \ 427 memcpy(dest, src, strnlen(src, min(_src_len, _dest_len))); \ 428 } while (0) 429 430 /** 431 * memtostr - Copy a possibly non-NUL-term string to a NUL-term string 432 * @dest: Pointer to destination NUL-terminates string 433 * @src: Pointer to character array (likely marked as __nonstring) 434 * 435 * This is a replacement for strncpy() uses where the source is not 436 * a NUL-terminated string. 437 * 438 * Note that sizes of @dest and @src must be known at compile-time. 439 */ 440 #define memtostr(dest, src) do { \ 441 const size_t _dest_len = __builtin_object_size(dest, 1); \ 442 const size_t _src_len = __builtin_object_size(src, 1); \ 443 const size_t _src_chars = strnlen(src, _src_len); \ 444 const size_t _copy_len = min(_dest_len - 1, _src_chars); \ 445 \ 446 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 447 !__builtin_constant_p(_src_len) || \ 448 _dest_len == 0 || _dest_len == (size_t)-1 || \ 449 _src_len == 0 || _src_len == (size_t)-1); \ 450 memcpy(dest, src, _copy_len); \ 451 dest[_copy_len] = '\0'; \ 452 } while (0) 453 454 /** 455 * memtostr_pad - Copy a possibly non-NUL-term string to a NUL-term string 456 * with NUL padding in the destination 457 * @dest: Pointer to destination NUL-terminates string 458 * @src: Pointer to character array (likely marked as __nonstring) 459 * 460 * This is a replacement for strncpy() uses where the source is not 461 * a NUL-terminated string. 462 * 463 * Note that sizes of @dest and @src must be known at compile-time. 464 */ 465 #define memtostr_pad(dest, src) do { \ 466 const size_t _dest_len = __builtin_object_size(dest, 1); \ 467 const size_t _src_len = __builtin_object_size(src, 1); \ 468 const size_t _src_chars = strnlen(src, _src_len); \ 469 const size_t _copy_len = min(_dest_len - 1, _src_chars); \ 470 \ 471 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 472 !__builtin_constant_p(_src_len) || \ 473 _dest_len == 0 || _dest_len == (size_t)-1 || \ 474 _src_len == 0 || _src_len == (size_t)-1); \ 475 memcpy(dest, src, _copy_len); \ 476 memset(&dest[_copy_len], 0, _dest_len - _copy_len); \ 477 } while (0) 478 479 /** 480 * memset_after - Set a value after a struct member to the end of a struct 481 * 482 * @obj: Address of target struct instance 483 * @v: Byte value to repeatedly write 484 * @member: after which struct member to start writing bytes 485 * 486 * This is good for clearing padding following the given member. 487 */ 488 #define memset_after(obj, v, member) \ 489 ({ \ 490 u8 *__ptr = (u8 *)(obj); \ 491 typeof(v) __val = (v); \ 492 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \ 493 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \ 494 }) 495 496 /** 497 * memset_startat - Set a value starting at a member to the end of a struct 498 * 499 * @obj: Address of target struct instance 500 * @v: Byte value to repeatedly write 501 * @member: struct member to start writing at 502 * 503 * Note that if there is padding between the prior member and the target 504 * member, memset_after() should be used to clear the prior padding. 505 */ 506 #define memset_startat(obj, v, member) \ 507 ({ \ 508 u8 *__ptr = (u8 *)(obj); \ 509 typeof(v) __val = (v); \ 510 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \ 511 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \ 512 }) 513 514 /** 515 * str_has_prefix - Test if a string has a given prefix 516 * @str: The string to test 517 * @prefix: The string to see if @str starts with 518 * 519 * A common way to test a prefix of a string is to do: 520 * strncmp(str, prefix, sizeof(prefix) - 1) 521 * 522 * But this can lead to bugs due to typos, or if prefix is a pointer 523 * and not a constant. Instead use str_has_prefix(). 524 * 525 * Returns: 526 * * strlen(@prefix) if @str starts with @prefix 527 * * 0 if @str does not start with @prefix 528 */ 529 static __always_inline size_t str_has_prefix(const char *str, const char *prefix) 530 { 531 size_t len = strlen(prefix); 532 return strncmp(str, prefix, len) == 0 ? len : 0; 533 } 534 535 #endif /* _LINUX_STRING_H_ */ 536