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/errno.h> /* for E2BIG */ 10 #include <linux/stdarg.h> 11 #include <uapi/linux/string.h> 12 13 extern char *strndup_user(const char __user *, long); 14 extern void *memdup_user(const void __user *, size_t); 15 extern void *vmemdup_user(const void __user *, size_t); 16 extern void *memdup_user_nul(const void __user *, size_t); 17 18 /* 19 * Include machine specific inline routines 20 */ 21 #include <asm/string.h> 22 23 #ifndef __HAVE_ARCH_STRCPY 24 extern char * strcpy(char *,const char *); 25 #endif 26 #ifndef __HAVE_ARCH_STRNCPY 27 extern char * strncpy(char *,const char *, __kernel_size_t); 28 #endif 29 #ifndef __HAVE_ARCH_STRLCPY 30 size_t strlcpy(char *, const char *, size_t); 31 #endif 32 #ifndef __HAVE_ARCH_STRSCPY 33 ssize_t strscpy(char *, const char *, size_t); 34 #endif 35 36 /* Wraps calls to strscpy()/memset(), no arch specific code required */ 37 ssize_t strscpy_pad(char *dest, const char *src, size_t count); 38 39 #ifndef __HAVE_ARCH_STRCAT 40 extern char * strcat(char *, const char *); 41 #endif 42 #ifndef __HAVE_ARCH_STRNCAT 43 extern char * strncat(char *, const char *, __kernel_size_t); 44 #endif 45 #ifndef __HAVE_ARCH_STRLCAT 46 extern size_t strlcat(char *, const char *, __kernel_size_t); 47 #endif 48 #ifndef __HAVE_ARCH_STRCMP 49 extern int strcmp(const char *,const char *); 50 #endif 51 #ifndef __HAVE_ARCH_STRNCMP 52 extern int strncmp(const char *,const char *,__kernel_size_t); 53 #endif 54 #ifndef __HAVE_ARCH_STRCASECMP 55 extern int strcasecmp(const char *s1, const char *s2); 56 #endif 57 #ifndef __HAVE_ARCH_STRNCASECMP 58 extern int strncasecmp(const char *s1, const char *s2, size_t n); 59 #endif 60 #ifndef __HAVE_ARCH_STRCHR 61 extern char * strchr(const char *,int); 62 #endif 63 #ifndef __HAVE_ARCH_STRCHRNUL 64 extern char * strchrnul(const char *,int); 65 #endif 66 extern char * strnchrnul(const char *, size_t, int); 67 #ifndef __HAVE_ARCH_STRNCHR 68 extern char * strnchr(const char *, size_t, int); 69 #endif 70 #ifndef __HAVE_ARCH_STRRCHR 71 extern char * strrchr(const char *,int); 72 #endif 73 extern char * __must_check skip_spaces(const char *); 74 75 extern char *strim(char *); 76 77 static inline __must_check char *strstrip(char *str) 78 { 79 return strim(str); 80 } 81 82 #ifndef __HAVE_ARCH_STRSTR 83 extern char * strstr(const char *, const char *); 84 #endif 85 #ifndef __HAVE_ARCH_STRNSTR 86 extern char * strnstr(const char *, const char *, size_t); 87 #endif 88 #ifndef __HAVE_ARCH_STRLEN 89 extern __kernel_size_t strlen(const char *); 90 #endif 91 #ifndef __HAVE_ARCH_STRNLEN 92 extern __kernel_size_t strnlen(const char *,__kernel_size_t); 93 #endif 94 #ifndef __HAVE_ARCH_STRPBRK 95 extern char * strpbrk(const char *,const char *); 96 #endif 97 #ifndef __HAVE_ARCH_STRSEP 98 extern char * strsep(char **,const char *); 99 #endif 100 #ifndef __HAVE_ARCH_STRSPN 101 extern __kernel_size_t strspn(const char *,const char *); 102 #endif 103 #ifndef __HAVE_ARCH_STRCSPN 104 extern __kernel_size_t strcspn(const char *,const char *); 105 #endif 106 107 #ifndef __HAVE_ARCH_MEMSET 108 extern void * memset(void *,int,__kernel_size_t); 109 #endif 110 111 #ifndef __HAVE_ARCH_MEMSET16 112 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t); 113 #endif 114 115 #ifndef __HAVE_ARCH_MEMSET32 116 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t); 117 #endif 118 119 #ifndef __HAVE_ARCH_MEMSET64 120 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t); 121 #endif 122 123 static inline void *memset_l(unsigned long *p, unsigned long v, 124 __kernel_size_t n) 125 { 126 if (BITS_PER_LONG == 32) 127 return memset32((uint32_t *)p, v, n); 128 else 129 return memset64((uint64_t *)p, v, n); 130 } 131 132 static inline void *memset_p(void **p, void *v, __kernel_size_t n) 133 { 134 if (BITS_PER_LONG == 32) 135 return memset32((uint32_t *)p, (uintptr_t)v, n); 136 else 137 return memset64((uint64_t *)p, (uintptr_t)v, n); 138 } 139 140 extern void **__memcat_p(void **a, void **b); 141 #define memcat_p(a, b) ({ \ 142 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \ 143 "type mismatch in memcat_p()"); \ 144 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \ 145 }) 146 147 #ifndef __HAVE_ARCH_MEMCPY 148 extern void * memcpy(void *,const void *,__kernel_size_t); 149 #endif 150 #ifndef __HAVE_ARCH_MEMMOVE 151 extern void * memmove(void *,const void *,__kernel_size_t); 152 #endif 153 #ifndef __HAVE_ARCH_MEMSCAN 154 extern void * memscan(void *,int,__kernel_size_t); 155 #endif 156 #ifndef __HAVE_ARCH_MEMCMP 157 extern int memcmp(const void *,const void *,__kernel_size_t); 158 #endif 159 #ifndef __HAVE_ARCH_BCMP 160 extern int bcmp(const void *,const void *,__kernel_size_t); 161 #endif 162 #ifndef __HAVE_ARCH_MEMCHR 163 extern void * memchr(const void *,int,__kernel_size_t); 164 #endif 165 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE 166 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) 167 { 168 memcpy(dst, src, cnt); 169 } 170 #endif 171 172 void *memchr_inv(const void *s, int c, size_t n); 173 char *strreplace(char *str, char old, char new); 174 175 extern void kfree_const(const void *x); 176 177 extern char *kstrdup(const char *s, gfp_t gfp) __malloc; 178 extern const char *kstrdup_const(const char *s, gfp_t gfp); 179 extern char *kstrndup(const char *s, size_t len, gfp_t gfp); 180 extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 181 extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2); 182 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); 183 184 extern char **argv_split(gfp_t gfp, const char *str, int *argcp); 185 extern void argv_free(char **argv); 186 187 extern bool sysfs_streq(const char *s1, const char *s2); 188 int match_string(const char * const *array, size_t n, const char *string); 189 int __sysfs_match_string(const char * const *array, size_t n, const char *s); 190 191 /** 192 * sysfs_match_string - matches given string in an array 193 * @_a: array of strings 194 * @_s: string to match with 195 * 196 * Helper for __sysfs_match_string(). Calculates the size of @a automatically. 197 */ 198 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s) 199 200 #ifdef CONFIG_BINARY_PRINTF 201 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args); 202 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf); 203 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4); 204 #endif 205 206 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, 207 const void *from, size_t available); 208 209 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out); 210 211 /** 212 * strstarts - does @str start with @prefix? 213 * @str: string to examine 214 * @prefix: prefix to look for. 215 */ 216 static inline bool strstarts(const char *str, const char *prefix) 217 { 218 return strncmp(str, prefix, strlen(prefix)) == 0; 219 } 220 221 size_t memweight(const void *ptr, size_t bytes); 222 223 /** 224 * memzero_explicit - Fill a region of memory (e.g. sensitive 225 * keying data) with 0s. 226 * @s: Pointer to the start of the area. 227 * @count: The size of the area. 228 * 229 * Note: usually using memset() is just fine (!), but in cases 230 * where clearing out _local_ data at the end of a scope is 231 * necessary, memzero_explicit() should be used instead in 232 * order to prevent the compiler from optimising away zeroing. 233 * 234 * memzero_explicit() doesn't need an arch-specific version as 235 * it just invokes the one of memset() implicitly. 236 */ 237 static inline void memzero_explicit(void *s, size_t count) 238 { 239 memset(s, 0, count); 240 barrier_data(s); 241 } 242 243 /** 244 * kbasename - return the last part of a pathname. 245 * 246 * @path: path to extract the filename from. 247 */ 248 static inline const char *kbasename(const char *path) 249 { 250 const char *tail = strrchr(path, '/'); 251 return tail ? tail + 1 : path; 252 } 253 254 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE) 255 #include <linux/fortify-string.h> 256 #endif 257 #ifndef unsafe_memcpy 258 #define unsafe_memcpy(dst, src, bytes, justification) \ 259 memcpy(dst, src, bytes) 260 #endif 261 262 void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count, 263 int pad); 264 265 /** 266 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer 267 * 268 * @dest: Pointer of destination character array (marked as __nonstring) 269 * @src: Pointer to NUL-terminated string 270 * @pad: Padding character to fill any remaining bytes of @dest after copy 271 * 272 * This is a replacement for strncpy() uses where the destination is not 273 * a NUL-terminated string, but with bounds checking on the source size, and 274 * an explicit padding character. If padding is not required, use strtomem(). 275 * 276 * Note that the size of @dest is not an argument, as the length of @dest 277 * must be discoverable by the compiler. 278 */ 279 #define strtomem_pad(dest, src, pad) do { \ 280 const size_t _dest_len = __builtin_object_size(dest, 1); \ 281 \ 282 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 283 _dest_len == (size_t)-1); \ 284 memcpy_and_pad(dest, _dest_len, src, strnlen(src, _dest_len), pad); \ 285 } while (0) 286 287 /** 288 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer 289 * 290 * @dest: Pointer of destination character array (marked as __nonstring) 291 * @src: Pointer to NUL-terminated string 292 * 293 * This is a replacement for strncpy() uses where the destination is not 294 * a NUL-terminated string, but with bounds checking on the source size, and 295 * without trailing padding. If padding is required, use strtomem_pad(). 296 * 297 * Note that the size of @dest is not an argument, as the length of @dest 298 * must be discoverable by the compiler. 299 */ 300 #define strtomem(dest, src) do { \ 301 const size_t _dest_len = __builtin_object_size(dest, 1); \ 302 \ 303 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \ 304 _dest_len == (size_t)-1); \ 305 memcpy(dest, src, min(_dest_len, strnlen(src, _dest_len))); \ 306 } while (0) 307 308 /** 309 * memset_after - Set a value after a struct member to the end of a struct 310 * 311 * @obj: Address of target struct instance 312 * @v: Byte value to repeatedly write 313 * @member: after which struct member to start writing bytes 314 * 315 * This is good for clearing padding following the given member. 316 */ 317 #define memset_after(obj, v, member) \ 318 ({ \ 319 u8 *__ptr = (u8 *)(obj); \ 320 typeof(v) __val = (v); \ 321 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \ 322 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \ 323 }) 324 325 /** 326 * memset_startat - Set a value starting at a member to the end of a struct 327 * 328 * @obj: Address of target struct instance 329 * @v: Byte value to repeatedly write 330 * @member: struct member to start writing at 331 * 332 * Note that if there is padding between the prior member and the target 333 * member, memset_after() should be used to clear the prior padding. 334 */ 335 #define memset_startat(obj, v, member) \ 336 ({ \ 337 u8 *__ptr = (u8 *)(obj); \ 338 typeof(v) __val = (v); \ 339 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \ 340 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \ 341 }) 342 343 /** 344 * str_has_prefix - Test if a string has a given prefix 345 * @str: The string to test 346 * @prefix: The string to see if @str starts with 347 * 348 * A common way to test a prefix of a string is to do: 349 * strncmp(str, prefix, sizeof(prefix) - 1) 350 * 351 * But this can lead to bugs due to typos, or if prefix is a pointer 352 * and not a constant. Instead use str_has_prefix(). 353 * 354 * Returns: 355 * * strlen(@prefix) if @str starts with @prefix 356 * * 0 if @str does not start with @prefix 357 */ 358 static __always_inline size_t str_has_prefix(const char *str, const char *prefix) 359 { 360 size_t len = strlen(prefix); 361 return strncmp(str, prefix, len) == 0 ? len : 0; 362 } 363 364 #endif /* _LINUX_STRING_H_ */ 365