include/linux/string.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_STRING_H_
   3 #define _LINUX_STRING_H_
   4
   5
   6 #include <linux/compiler.h>     /* for inline */
   7 #include <linux/types.h>        /* for size_t */
   8 #include <linux/stddef.h>       /* for NULL */
   9 #include <stdarg.h>
  10 #include <uapi/linux/string.h>
  11
  12 extern char *strndup_user(const char __user *, long);
  13 extern void *memdup_user(const void __user *, size_t);
  14 extern void *memdup_user_nul(const void __user *, size_t);
  15
  16 /*
  17  * Include machine specific inline routines
  18  */
  19 #include <asm/string.h>
  20
  21 #ifndef __HAVE_ARCH_STRCPY
  22 extern char * strcpy(char *,const char *);
  23 #endif
  24 #ifndef __HAVE_ARCH_STRNCPY
  25 extern char * strncpy(char *,const char *, __kernel_size_t);
  26 #endif
  27 #ifndef __HAVE_ARCH_STRLCPY
  28 size_t strlcpy(char *, const char *, size_t);
  29 #endif
  30 #ifndef __HAVE_ARCH_STRSCPY
  31 ssize_t strscpy(char *, const char *, size_t);
  32 #endif
  33 #ifndef __HAVE_ARCH_STRCAT
  34 extern char * strcat(char *, const char *);
  35 #endif
  36 #ifndef __HAVE_ARCH_STRNCAT
  37 extern char * strncat(char *, const char *, __kernel_size_t);
  38 #endif
  39 #ifndef __HAVE_ARCH_STRLCAT
  40 extern size_t strlcat(char *, const char *, __kernel_size_t);
  41 #endif
  42 #ifndef __HAVE_ARCH_STRCMP
  43 extern int strcmp(const char *,const char *);
  44 #endif
  45 #ifndef __HAVE_ARCH_STRNCMP
  46 extern int strncmp(const char *,const char *,__kernel_size_t);
  47 #endif
  48 #ifndef __HAVE_ARCH_STRCASECMP
  49 extern int strcasecmp(const char *s1, const char *s2);
  50 #endif
  51 #ifndef __HAVE_ARCH_STRNCASECMP
  52 extern int strncasecmp(const char *s1, const char *s2, size_t n);
  53 #endif
  54 #ifndef __HAVE_ARCH_STRCHR
  55 extern char * strchr(const char *,int);
  56 #endif
  57 #ifndef __HAVE_ARCH_STRCHRNUL
  58 extern char * strchrnul(const char *,int);
  59 #endif
  60 #ifndef __HAVE_ARCH_STRNCHR
  61 extern char * strnchr(const char *, size_t, int);
  62 #endif
  63 #ifndef __HAVE_ARCH_STRRCHR
  64 extern char * strrchr(const char *,int);
  65 #endif
  66 extern char * __must_check skip_spaces(const char *);
  67
  68 extern char *strim(char *);
  69
  70 static inline __must_check char *strstrip(char *str)
  71 {
  72         return strim(str);
  73 }
  74
  75 #ifndef __HAVE_ARCH_STRSTR
  76 extern char * strstr(const char *, const char *);
  77 #endif
  78 #ifndef __HAVE_ARCH_STRNSTR
  79 extern char * strnstr(const char *, const char *, size_t);
  80 #endif
  81 #ifndef __HAVE_ARCH_STRLEN
  82 extern __kernel_size_t strlen(const char *);
  83 #endif
  84 #ifndef __HAVE_ARCH_STRNLEN
  85 extern __kernel_size_t strnlen(const char *,__kernel_size_t);
  86 #endif
  87 #ifndef __HAVE_ARCH_STRPBRK
  88 extern char * strpbrk(const char *,const char *);
  89 #endif
  90 #ifndef __HAVE_ARCH_STRSEP
  91 extern char * strsep(char **,const char *);
  92 #endif
  93 #ifndef __HAVE_ARCH_STRSPN
  94 extern __kernel_size_t strspn(const char *,const char *);
  95 #endif
  96 #ifndef __HAVE_ARCH_STRCSPN
  97 extern __kernel_size_t strcspn(const char *,const char *);
  98 #endif
  99
 100 #ifndef __HAVE_ARCH_MEMSET
 101 extern void * memset(void *,int,__kernel_size_t);
 102 #endif
 103
 104 #ifndef __HAVE_ARCH_MEMSET16
 105 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
 106 #endif
 107
 108 #ifndef __HAVE_ARCH_MEMSET32
 109 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
 110 #endif
 111
 112 #ifndef __HAVE_ARCH_MEMSET64
 113 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
 114 #endif
 115
 116 static inline void *memset_l(unsigned long *p, unsigned long v,
 117                 __kernel_size_t n)
 118 {
 119         if (BITS_PER_LONG == 32)
 120                 return memset32((uint32_t *)p, v, n);
 121         else
 122                 return memset64((uint64_t *)p, v, n);
 123 }
 124
 125 static inline void *memset_p(void **p, void *v, __kernel_size_t n)
 126 {
 127         if (BITS_PER_LONG == 32)
 128                 return memset32((uint32_t *)p, (uintptr_t)v, n);
 129         else
 130                 return memset64((uint64_t *)p, (uintptr_t)v, n);
 131 }
 132
 133 #ifndef __HAVE_ARCH_MEMCPY
 134 extern void * memcpy(void *,const void *,__kernel_size_t);
 135 #endif
 136 #ifndef __HAVE_ARCH_MEMMOVE
 137 extern void * memmove(void *,const void *,__kernel_size_t);
 138 #endif
 139 #ifndef __HAVE_ARCH_MEMSCAN
 140 extern void * memscan(void *,int,__kernel_size_t);
 141 #endif
 142 #ifndef __HAVE_ARCH_MEMCMP
 143 extern int memcmp(const void *,const void *,__kernel_size_t);
 144 #endif
 145 #ifndef __HAVE_ARCH_BCMP
 146 extern int bcmp(const void *,const void *,__kernel_size_t);
 147 #endif
 148 #ifndef __HAVE_ARCH_MEMCHR
 149 extern void * memchr(const void *,int,__kernel_size_t);
 150 #endif
 151 #ifndef __HAVE_ARCH_MEMCPY_MCSAFE
 152 static inline __must_check int memcpy_mcsafe(void *dst, const void *src,
 153                 size_t cnt)
 154 {
 155         memcpy(dst, src, cnt);
 156         return 0;
 157 }
 158 #endif
 159 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
 160 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
 161 {
 162         memcpy(dst, src, cnt);
 163 }
 164 #endif
 165 void *memchr_inv(const void *s, int c, size_t n);
 166 char *strreplace(char *s, char old, char new);
 167
 168 extern void kfree_const(const void *x);
 169
 170 extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
 171 extern const char *kstrdup_const(const char *s, gfp_t gfp);
 172 extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
 173 extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
 174 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
 175
 176 extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
 177 extern void argv_free(char **argv);
 178
 179 extern bool sysfs_streq(const char *s1, const char *s2);
 180 extern int kstrtobool(const char *s, bool *res);
 181 static inline int strtobool(const char *s, bool *res)
 182 {
 183         return kstrtobool(s, res);
 184 }
 185
 186 int match_string(const char * const *array, size_t n, const char *string);
 187 int __sysfs_match_string(const char * const *array, size_t n, const char *s);
 188
 189 /**
 190  * sysfs_match_string - matches given string in an array
 191  * @_a: array of strings
 192  * @_s: string to match with
 193  *
 194  * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
 195  */
 196 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
 197
 198 #ifdef CONFIG_BINARY_PRINTF
 199 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
 200 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
 201 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
 202 #endif
 203
 204 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
 205                                        const void *from, size_t available);
 206
 207 /**
 208  * strstarts - does @str start with @prefix?
 209  * @str: string to examine
 210  * @prefix: prefix to look for.
 211  */
 212 static inline bool strstarts(const char *str, const char *prefix)
 213 {
 214         return strncmp(str, prefix, strlen(prefix)) == 0;
 215 }
 216
 217 size_t memweight(const void *ptr, size_t bytes);
 218 void memzero_explicit(void *s, size_t count);
 219
 220 /**
 221  * kbasename - return the last part of a pathname.
 222  *
 223  * @path: path to extract the filename from.
 224  */
 225 static inline const char *kbasename(const char *path)
 226 {
 227         const char *tail = strrchr(path, '/');
 228         return tail ? tail + 1 : path;
 229 }
 230
 231 #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
 232 #define __RENAME(x) __asm__(#x)
 233
 234 void fortify_panic(const char *name) __noreturn __cold;
 235 void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
 236 void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
 237 void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter");
 238 void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
 239
 240 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
 241 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
 242 {
 243         size_t p_size = __builtin_object_size(p, 0);
 244         if (__builtin_constant_p(size) && p_size < size)
 245                 __write_overflow();
 246         if (p_size < size)
 247                 fortify_panic(__func__);
 248         return __builtin_strncpy(p, q, size);
 249 }
 250
 251 __FORTIFY_INLINE char *strcat(char *p, const char *q)
 252 {
 253         size_t p_size = __builtin_object_size(p, 0);
 254         if (p_size == (size_t)-1)
 255                 return __builtin_strcat(p, q);
 256         if (strlcat(p, q, p_size) >= p_size)
 257                 fortify_panic(__func__);
 258         return p;
 259 }
 260
 261 __FORTIFY_INLINE __kernel_size_t strlen(const char *p)
 262 {
 263         __kernel_size_t ret;
 264         size_t p_size = __builtin_object_size(p, 0);
 265
 266         /* Work around gcc excess stack consumption issue */
 267         if (p_size == (size_t)-1 ||
 268             (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
 269                 return __builtin_strlen(p);
 270         ret = strnlen(p, p_size);
 271         if (p_size <= ret)
 272                 fortify_panic(__func__);
 273         return ret;
 274 }
 275
 276 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
 277 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
 278 {
 279         size_t p_size = __builtin_object_size(p, 0);
 280         __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
 281         if (p_size <= ret && maxlen != ret)
 282                 fortify_panic(__func__);
 283         return ret;
 284 }
 285
 286 /* defined after fortified strlen to reuse it */
 287 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
 288 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
 289 {
 290         size_t ret;
 291         size_t p_size = __builtin_object_size(p, 0);
 292         size_t q_size = __builtin_object_size(q, 0);
 293         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 294                 return __real_strlcpy(p, q, size);
 295         ret = strlen(q);
 296         if (size) {
 297                 size_t len = (ret >= size) ? size - 1 : ret;
 298                 if (__builtin_constant_p(len) && len >= p_size)
 299                         __write_overflow();
 300                 if (len >= p_size)
 301                         fortify_panic(__func__);
 302                 __builtin_memcpy(p, q, len);
 303                 p[len] = '\0';
 304         }
 305         return ret;
 306 }
 307
 308 /* defined after fortified strlen and strnlen to reuse them */
 309 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
 310 {
 311         size_t p_len, copy_len;
 312         size_t p_size = __builtin_object_size(p, 0);
 313         size_t q_size = __builtin_object_size(q, 0);
 314         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 315                 return __builtin_strncat(p, q, count);
 316         p_len = strlen(p);
 317         copy_len = strnlen(q, count);
 318         if (p_size < p_len + copy_len + 1)
 319                 fortify_panic(__func__);
 320         __builtin_memcpy(p + p_len, q, copy_len);
 321         p[p_len + copy_len] = '\0';
 322         return p;
 323 }
 324
 325 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
 326 {
 327         size_t p_size = __builtin_object_size(p, 0);
 328         if (__builtin_constant_p(size) && p_size < size)
 329                 __write_overflow();
 330         if (p_size < size)
 331                 fortify_panic(__func__);
 332         return __builtin_memset(p, c, size);
 333 }
 334
 335 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
 336 {
 337         size_t p_size = __builtin_object_size(p, 0);
 338         size_t q_size = __builtin_object_size(q, 0);
 339         if (__builtin_constant_p(size)) {
 340                 if (p_size < size)
 341                         __write_overflow();
 342                 if (q_size < size)
 343                         __read_overflow2();
 344         }
 345         if (p_size < size || q_size < size)
 346                 fortify_panic(__func__);
 347         return __builtin_memcpy(p, q, size);
 348 }
 349
 350 __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
 351 {
 352         size_t p_size = __builtin_object_size(p, 0);
 353         size_t q_size = __builtin_object_size(q, 0);
 354         if (__builtin_constant_p(size)) {
 355                 if (p_size < size)
 356                         __write_overflow();
 357                 if (q_size < size)
 358                         __read_overflow2();
 359         }
 360         if (p_size < size || q_size < size)
 361                 fortify_panic(__func__);
 362         return __builtin_memmove(p, q, size);
 363 }
 364
 365 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
 366 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
 367 {
 368         size_t p_size = __builtin_object_size(p, 0);
 369         if (__builtin_constant_p(size) && p_size < size)
 370                 __read_overflow();
 371         if (p_size < size)
 372                 fortify_panic(__func__);
 373         return __real_memscan(p, c, size);
 374 }
 375
 376 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
 377 {
 378         size_t p_size = __builtin_object_size(p, 0);
 379         size_t q_size = __builtin_object_size(q, 0);
 380         if (__builtin_constant_p(size)) {
 381                 if (p_size < size)
 382                         __read_overflow();
 383                 if (q_size < size)
 384                         __read_overflow2();
 385         }
 386         if (p_size < size || q_size < size)
 387                 fortify_panic(__func__);
 388         return __builtin_memcmp(p, q, size);
 389 }
 390
 391 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
 392 {
 393         size_t p_size = __builtin_object_size(p, 0);
 394         if (__builtin_constant_p(size) && p_size < size)
 395                 __read_overflow();
 396         if (p_size < size)
 397                 fortify_panic(__func__);
 398         return __builtin_memchr(p, c, size);
 399 }
 400
 401 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
 402 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
 403 {
 404         size_t p_size = __builtin_object_size(p, 0);
 405         if (__builtin_constant_p(size) && p_size < size)
 406                 __read_overflow();
 407         if (p_size < size)
 408                 fortify_panic(__func__);
 409         return __real_memchr_inv(p, c, size);
 410 }
 411
 412 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
 413 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
 414 {
 415         size_t p_size = __builtin_object_size(p, 0);
 416         if (__builtin_constant_p(size) && p_size < size)
 417                 __read_overflow();
 418         if (p_size < size)
 419                 fortify_panic(__func__);
 420         return __real_kmemdup(p, size, gfp);
 421 }
 422
 423 /* defined after fortified strlen and memcpy to reuse them */
 424 __FORTIFY_INLINE char *strcpy(char *p, const char *q)
 425 {
 426         size_t p_size = __builtin_object_size(p, 0);
 427         size_t q_size = __builtin_object_size(q, 0);
 428         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 429                 return __builtin_strcpy(p, q);
 430         memcpy(p, q, strlen(q) + 1);
 431         return p;
 432 }
 433
 434 #endif
 435
 436 /**
 437  * memcpy_and_pad - Copy one buffer to another with padding
 438  * @dest: Where to copy to
 439  * @dest_len: The destination buffer size
 440  * @src: Where to copy from
 441  * @count: The number of bytes to copy
 442  * @pad: Character to use for padding if space is left in destination.
 443  */
 444 static inline void memcpy_and_pad(void *dest, size_t dest_len,
 445                                   const void *src, size_t count, int pad)
 446 {
 447         if (dest_len > count) {
 448                 memcpy(dest, src, count);
 449                 memset(dest + count, pad,  dest_len - count);
 450         } else
 451                 memcpy(dest, src, dest_len);
 452 }
 453
 454 #endif /* _LINUX_STRING_H_ */