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