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