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 __must_be_cstr(dst) + __must_be_cstr(src)) 81 #define __strscpy1(dst, src, size) \ 82 sized_strscpy(dst, src, size + __must_be_cstr(dst) + __must_be_cstr(src)) 83 84 #define __strscpy_pad0(dst, src, ...) \ 85 sized_strscpy_pad(dst, src, sizeof(dst) + __must_be_array(dst) + \ 86 __must_be_cstr(dst) + __must_be_cstr(src)) 87 #define __strscpy_pad1(dst, src, size) \ 88 sized_strscpy_pad(dst, src, size + __must_be_cstr(dst) + __must_be_cstr(src)) 89 90 /** 91 * strscpy - Copy a C-string into a sized buffer 92 * @dst: Where to copy the string to 93 * @src: Where to copy the string from 94 * @...: Size of destination buffer (optional) 95 * 96 * Copy the source string @src, or as much of it as fits, into the 97 * destination @dst buffer. The behavior is undefined if the string 98 * buffers overlap. The destination @dst buffer is always NUL terminated, 99 * unless it's zero-sized. 100 * 101 * The size argument @... is only required when @dst is not an array, or 102 * when the copy needs to be smaller than sizeof(@dst). 103 * 104 * Preferred to strncpy() since it always returns a valid string, and 105 * doesn't unnecessarily force the tail of the destination buffer to be 106 * zero padded. If padding is desired please use strscpy_pad(). 107 * 108 * Returns the number of characters copied in @dst (not including the 109 * trailing %NUL) or -E2BIG if @size is 0 or the copy from @src was 110 * truncated. 111 */ 112 #define strscpy(dst, src, ...) \ 113 CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__) 114 115 #define sized_strscpy_pad(dest, src, count) ({ \ 116 char *__dst = (dest); \ 117 const char *__src = (src); \ 118 const size_t __count = (count); \ 119 ssize_t __wrote; \ 120 \ 121 __wrote = sized_strscpy(__dst, __src, __count); \ 122 if (__wrote >= 0 && __wrote < __count) \ 123 memset(__dst + __wrote + 1, 0, __count - __wrote - 1); \ 124 __wrote; \ 125 }) 126 127 /** 128 * strscpy_pad() - Copy a C-string into a sized buffer 129 * @dst: Where to copy the string to 130 * @src: Where to copy the string from 131 * @...: Size of destination buffer 132 * 133 * Copy the string, or as much of it as fits, into the dest buffer. The 134 * behavior is undefined if the string buffers overlap. The destination 135 * buffer is always %NUL terminated, unless it's zero-sized. 136 * 137 * If the source string is shorter than the destination buffer, the 138 * remaining bytes in the buffer will be filled with %NUL bytes. 139 * 140 * For full explanation of why you may want to consider using the 141 * 'strscpy' functions please see the function docstring for strscpy(). 142 * 143 * Returns: 144 * * The number of characters copied (not including the trailing %NULs) 145 * * -E2BIG if count is 0 or @src was truncated. 146 */ 147 #define strscpy_pad(dst, src, ...) \ 148 CONCATENATE(__strscpy_pad, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__) 149 150 #ifndef __HAVE_ARCH_STRCAT 151 extern char * strcat(char *, const char *); 152 #endif 153 #ifndef __HAVE_ARCH_STRNCAT 154 extern char * strncat(char *, const char *, __kernel_size_t); 155 #endif 156 #ifndef __HAVE_ARCH_STRLCAT 157 extern size_t strlcat(char *, const char *, __kernel_size_t); 158 #endif 159 #ifndef __HAVE_ARCH_STRCMP 160 extern int strcmp(const char *,const char *); 161 #endif 162 #ifndef __HAVE_ARCH_STRNCMP 163 extern int strncmp(const char *,const char *,__kernel_size_t); 164 #endif 165 #ifndef __HAVE_ARCH_STRCASECMP 166 extern int strcasecmp(const char *s1, const char *s2); 167 #endif 168 #ifndef __HAVE_ARCH_STRNCASECMP 169 extern int strncasecmp(const char *s1, const char *s2, size_t n); 170 #endif 171 #ifndef __HAVE_ARCH_STRCHR 172 extern char * strchr(const char *,int); 173 #endif 174 #ifndef __HAVE_ARCH_STRCHRNUL 175 extern char * strchrnul(const char *,int); 176 #endif 177 extern char * strnchrnul(const char *, size_t, int); 178 #ifndef __HAVE_ARCH_STRNCHR 179 extern char * strnchr(const char *, size_t, int); 180 #endif 181 #ifndef __HAVE_ARCH_STRRCHR 182 extern char * strrchr(const char *,int); 183 #endif 184 extern char * __must_check skip_spaces(const char *); 185 186 extern char *strim(char *); 187 188 static inline __must_check char *strstrip(char *str) 189 { 190 return strim(str); 191 } 192 193 #ifndef __HAVE_ARCH_STRSTR 194 extern char * strstr(const char *, const char *); 195 #endif 196 #ifndef __HAVE_ARCH_STRNSTR 197 extern char * strnstr(const char *, const char *, size_t); 198 #endif 199 #ifndef __HAVE_ARCH_STRLEN 200 extern __kernel_size_t strlen(const char *); 201 #endif 202 #ifndef __HAVE_ARCH_STRNLEN 203 extern __kernel_size_t strnlen(const char *,__kernel_size_t); 204 #endif 205 #ifndef __HAVE_ARCH_STRPBRK 206 extern char * strpbrk(const char *,const char *); 207 #endif 208 #ifndef __HAVE_ARCH_STRSEP 209 extern char * strsep(char **,const char *); 210 #endif 211 #ifndef __HAVE_ARCH_STRSPN 212 extern __kernel_size_t strspn(const char *,const char *); 213 #endif 214 #ifndef __HAVE_ARCH_STRCSPN 215 extern __kernel_size_t strcspn(const char *,const char *); 216 #endif 217 218 #ifndef __HAVE_ARCH_MEMSET 219 extern void * memset(void *,int,__kernel_size_t); 220 #endif 221 222 #ifndef __HAVE_ARCH_MEMSET16 223 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); 224 #endif 225 226 #ifndef __HAVE_ARCH_MEMSET32 227 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t); 228 #endif 229 230 #ifndef __HAVE_ARCH_MEMSET64 231 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t); 232 #endif 233 234 static inline void *memset_l(unsigned long *p, unsigned long v, 235 __kernel_size_t n) 236 { 237 if (BITS_PER_LONG == 32) 238 return memset32((uint32_t *)p, v, n); 239 else 240 return memset64((uint64_t *)p, v, n); 241 } 242 243 static inline void *memset_p(void **p, void *v, __kernel_size_t n) 244 { 245 if (BITS_PER_LONG == 32) 246 return memset32((uint32_t *)p, (uintptr_t)v, n); 247 else 248 return memset64((uint64_t *)p, (uintptr_t)v, n); 249 } 250 251 extern void **__memcat_p(void **a, void **b); 252 #define memcat_p(a, b) ({ \ 253 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \ 254 "type mismatch in memcat_p()"); \ 255 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \ 256 }) 257 258 #ifndef __HAVE_ARCH_MEMCPY 259 extern void * memcpy(void *,const void *,__kernel_size_t); 260 #endif 261 #ifndef __HAVE_ARCH_MEMMOVE 262 extern void * memmove(void *,const void *,__kernel_size_t); 263 #endif 264 #ifndef __HAVE_ARCH_MEMSCAN 265 extern void * memscan(void *,int,__kernel_size_t); 266 #endif 267 #ifndef __HAVE_ARCH_MEMCMP 268 extern int memcmp(const void *,const void *,__kernel_size_t); 269 #endif 270 #ifndef __HAVE_ARCH_BCMP 271 extern int bcmp(const void *,const void *,__kernel_size_t); 272 #endif 273 #ifndef __HAVE_ARCH_MEMCHR 274 extern void * memchr(const void *,int,__kernel_size_t); 275 #endif 276 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE 277 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) 278 { 279 memcpy(dst, src, cnt); 280 } 281 #endif 282 283 void *memchr_inv(const void *s, int c, size_t n); 284 char *strreplace(char *str, char old, char new); 285 286 extern void kfree_const(const void *x); 287 288 extern char *kstrdup(const char *s, gfp_t gfp) __malloc; 289 extern const char *kstrdup_const(const char *s, gfp_t gfp); 290 extern char *kstrndup(const char *s, size_t len, gfp_t gfp); 291 extern void *kmemdup_noprof(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 292 #define kmemdup(...) alloc_hooks(kmemdup_noprof(__VA_ARGS__)) 293 294 extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 295 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); 296 extern void *kmemdup_array(const void *src, size_t count, size_t element_size, gfp_t gfp) 297 __realloc_size(2, 3); 298 299 /* lib/argv_split.c */ 300 extern char **argv_split(gfp_t gfp, const char *str, int *argcp); 301 extern void argv_free(char **argv); 302 303 /* lib/cmdline.c */ 304 extern int get_option(char **str, int *pint); 305 extern char *get_options(const char *str, int nints, int *ints); 306 extern unsigned long long memparse(const char *ptr, char **retptr); 307 extern bool parse_option_str(const char *str, const char *option); 308 extern char *next_arg(char *args, char **param, char **val); 309 310 extern bool sysfs_streq(const char *s1, const char *s2); 311 int match_string(const char * const *array, size_t n, const char *string); 312 int __sysfs_match_string(const char * const *array, size_t n, const char *s); 313 314 /** 315 * sysfs_match_string - matches given string in an array 316 * @_a: array of strings 317 * @_s: string to match with 318 * 319 * Helper for __sysfs_match_string(). Calculates the size of @a automatically. 320 */ 321 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s) 322 323 #ifdef CONFIG_BINARY_PRINTF 324 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); 325 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf); 326 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4); 327 #endif 328 329 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 330 const void *from, size_t available); 331 332 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); 333 334 /** 335 * strstarts - does @str start with @prefix? 336 * @str: string to examine 337 * @prefix: prefix to look for. 338 */ 339 static inline bool strstarts(const char *str, const char *prefix) 340 { 341 return strncmp(str, prefix, strlen(prefix)) == 0; 342 } 343 344 size_t memweight(const void *ptr, size_t bytes); 345 346 /** 347 * memzero_explicit - Fill a region of memory (e.g. sensitive 348 * keying data) with 0s. 349 * @s: Pointer to the start of the area. 350 * @count: The size of the area. 351 * 352 * Note: usually using memset() is just fine (!), but in cases 353 * where clearing out _local_ data at the end of a scope is 354 * necessary, memzero_explicit() should be used instead in 355 * order to prevent the compiler from optimising away zeroing. 356 * 357 * memzero_explicit() doesn't need an arch-specific version as 358 * it just invokes the one of memset() implicitly. 359 */ 360 static inline void memzero_explicit(void *s, size_t count) 361 { 362 memset(s, 0, count); 363 barrier_data(s); 364 } 365 366 /** 367 * kbasename - return the last part of a pathname. 368 * 369 * @path: path to extract the filename from. 370 */ 371 static inline const char *kbasename(const char *path) 372 { 373 const char *tail = strrchr(path, '/'); 374 return tail ? tail + 1 : path; 375 } 376 377 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE) 378 #include <linux/fortify-string.h> 379 #endif 380 #ifndef unsafe_memcpy 381 #define unsafe_memcpy(dst, src, bytes, justification) \ 382 memcpy(dst, src, bytes) 383 #endif 384 385 void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count, 386 int pad); 387 388 /** 389 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer 390 * 391 * @dest: Pointer of destination character array (marked as __nonstring) 392 * @src: Pointer to NUL-terminated string 393 * @pad: Padding character to fill any remaining bytes of @dest after copy 394 * 395 * This is a replacement for strncpy() uses where the destination is not 396 * a NUL-terminated string, but with bounds checking on the source size, and 397 * an explicit padding character. If padding is not required, use strtomem(). 398 * 399 * Note that the size of @dest is not an argument, as the length of @dest 400 * must be discoverable by the compiler. 401 */ 402 #define strtomem_pad(dest, src, pad) do { \ 403 const size_t _dest_len = __builtin_object_size(dest, 1); \ 404 const size_t _src_len = __builtin_object_size(src, 1); \ 405 \ 406 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 407 _dest_len == (size_t)-1); \ 408 memcpy_and_pad(dest, _dest_len, src, \ 409 strnlen(src, min(_src_len, _dest_len)), pad); \ 410 } while (0) 411 412 /** 413 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer 414 * 415 * @dest: Pointer of destination character array (marked as __nonstring) 416 * @src: Pointer to NUL-terminated string 417 * 418 * This is a replacement for strncpy() uses where the destination is not 419 * a NUL-terminated string, but with bounds checking on the source size, and 420 * without trailing padding. If padding is required, use strtomem_pad(). 421 * 422 * Note that the size of @dest is not an argument, as the length of @dest 423 * must be discoverable by the compiler. 424 */ 425 #define strtomem(dest, src) do { \ 426 const size_t _dest_len = __builtin_object_size(dest, 1); \ 427 const size_t _src_len = __builtin_object_size(src, 1); \ 428 \ 429 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 430 _dest_len == (size_t)-1); \ 431 memcpy(dest, src, strnlen(src, min(_src_len, _dest_len))); \ 432 } while (0) 433 434 /** 435 * memtostr - Copy a possibly non-NUL-term string to a NUL-term string 436 * @dest: Pointer to destination NUL-terminates string 437 * @src: Pointer to character array (likely marked as __nonstring) 438 * 439 * This is a replacement for strncpy() uses where the source is not 440 * a NUL-terminated string. 441 * 442 * Note that sizes of @dest and @src must be known at compile-time. 443 */ 444 #define memtostr(dest, src) do { \ 445 const size_t _dest_len = __builtin_object_size(dest, 1); \ 446 const size_t _src_len = __builtin_object_size(src, 1); \ 447 const size_t _src_chars = strnlen(src, _src_len); \ 448 const size_t _copy_len = min(_dest_len - 1, _src_chars); \ 449 \ 450 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 451 !__builtin_constant_p(_src_len) || \ 452 _dest_len == 0 || _dest_len == (size_t)-1 || \ 453 _src_len == 0 || _src_len == (size_t)-1); \ 454 memcpy(dest, src, _copy_len); \ 455 dest[_copy_len] = '\0'; \ 456 } while (0) 457 458 /** 459 * memtostr_pad - Copy a possibly non-NUL-term string to a NUL-term string 460 * with NUL padding in the destination 461 * @dest: Pointer to destination NUL-terminates string 462 * @src: Pointer to character array (likely marked as __nonstring) 463 * 464 * This is a replacement for strncpy() uses where the source is not 465 * a NUL-terminated string. 466 * 467 * Note that sizes of @dest and @src must be known at compile-time. 468 */ 469 #define memtostr_pad(dest, src) do { \ 470 const size_t _dest_len = __builtin_object_size(dest, 1); \ 471 const size_t _src_len = __builtin_object_size(src, 1); \ 472 const size_t _src_chars = strnlen(src, _src_len); \ 473 const size_t _copy_len = min(_dest_len - 1, _src_chars); \ 474 \ 475 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 476 !__builtin_constant_p(_src_len) || \ 477 _dest_len == 0 || _dest_len == (size_t)-1 || \ 478 _src_len == 0 || _src_len == (size_t)-1); \ 479 memcpy(dest, src, _copy_len); \ 480 memset(&dest[_copy_len], 0, _dest_len - _copy_len); \ 481 } while (0) 482 483 /** 484 * memset_after - Set a value after a struct member to the end of a struct 485 * 486 * @obj: Address of target struct instance 487 * @v: Byte value to repeatedly write 488 * @member: after which struct member to start writing bytes 489 * 490 * This is good for clearing padding following the given member. 491 */ 492 #define memset_after(obj, v, member) \ 493 ({ \ 494 u8 *__ptr = (u8 *)(obj); \ 495 typeof(v) __val = (v); \ 496 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \ 497 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \ 498 }) 499 500 /** 501 * memset_startat - Set a value starting at a member to the end of a struct 502 * 503 * @obj: Address of target struct instance 504 * @v: Byte value to repeatedly write 505 * @member: struct member to start writing at 506 * 507 * Note that if there is padding between the prior member and the target 508 * member, memset_after() should be used to clear the prior padding. 509 */ 510 #define memset_startat(obj, v, member) \ 511 ({ \ 512 u8 *__ptr = (u8 *)(obj); \ 513 typeof(v) __val = (v); \ 514 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \ 515 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \ 516 }) 517 518 /** 519 * str_has_prefix - Test if a string has a given prefix 520 * @str: The string to test 521 * @prefix: The string to see if @str starts with 522 * 523 * A common way to test a prefix of a string is to do: 524 * strncmp(str, prefix, sizeof(prefix) - 1) 525 * 526 * But this can lead to bugs due to typos, or if prefix is a pointer 527 * and not a constant. Instead use str_has_prefix(). 528 * 529 * Returns: 530 * * strlen(@prefix) if @str starts with @prefix 531 * * 0 if @str does not start with @prefix 532 */ 533 static __always_inline size_t str_has_prefix(const char *str, const char *prefix) 534 { 535 size_t len = strlen(prefix); 536 return strncmp(str, prefix, len) == 0 ? len : 0; 537 } 538 539 #endif /* _LINUX_STRING_H_ */ 540