root/include/linux/string.h

INCLUDED FROM

DEFINITIONS

1. strstrip
2. memset_l
3. memset_p
4. memcpy_mcsafe
5. memcpy_flushcache
6. kstrdup
7. bprintf
8. memzero_explicit
9. kbasename
10. fortify_panic
11. strcat
12. strlen
13. __real_strnlen
14. __real_strlcpy
15. strncat
16. memset
17. memcpy
18. memmove
19. __real_memscan
20. memcmp
21. memchr
22. __real_memchr_inv
23. __real_kmemdup
24. strcpy
25. memcpy_and_pad
26. str_has_prefix

   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 *vmemdup_user(const void __user *, size_t);
  15 extern void *memdup_user_nul(const void __user *, size_t);
  16 
  17 /*
  18  * Include machine specific inline routines
  19  */
  20 #include <asm/string.h>
  21 
  22 #ifndef __HAVE_ARCH_STRCPY
  23 extern char * strcpy(char *,const char *);
  24 #endif
  25 #ifndef __HAVE_ARCH_STRNCPY
  26 extern char * strncpy(char *,const char *, __kernel_size_t);
  27 #endif
  28 #ifndef __HAVE_ARCH_STRLCPY
  29 size_t strlcpy(char *, const char *, size_t);
  30 #endif
  31 #ifndef __HAVE_ARCH_STRSCPY
  32 ssize_t strscpy(char *, const char *, size_t);
  33 #endif
  34 
  35 /* Wraps calls to strscpy()/memset(), no arch specific code required */
  36 ssize_t strscpy_pad(char *dest, const char *src, size_t count);
  37 
  38 #ifndef __HAVE_ARCH_STRCAT
  39 extern char * strcat(char *, const char *);
  40 #endif
  41 #ifndef __HAVE_ARCH_STRNCAT
  42 extern char * strncat(char *, const char *, __kernel_size_t);
  43 #endif
  44 #ifndef __HAVE_ARCH_STRLCAT
  45 extern size_t strlcat(char *, const char *, __kernel_size_t);
  46 #endif
  47 #ifndef __HAVE_ARCH_STRCMP
  48 extern int strcmp(const char *,const char *);
  49 #endif
  50 #ifndef __HAVE_ARCH_STRNCMP
  51 extern int strncmp(const char *,const char *,__kernel_size_t);
  52 #endif
  53 #ifndef __HAVE_ARCH_STRCASECMP
  54 extern int strcasecmp(const char *s1, const char *s2);
  55 #endif
  56 #ifndef __HAVE_ARCH_STRNCASECMP
  57 extern int strncasecmp(const char *s1, const char *s2, size_t n);
  58 #endif
  59 #ifndef __HAVE_ARCH_STRCHR
  60 extern char * strchr(const char *,int);
  61 #endif
  62 #ifndef __HAVE_ARCH_STRCHRNUL
  63 extern char * strchrnul(const char *,int);
  64 #endif
  65 #ifndef __HAVE_ARCH_STRNCHR
  66 extern char * strnchr(const char *, size_t, int);
  67 #endif
  68 #ifndef __HAVE_ARCH_STRRCHR
  69 extern char * strrchr(const char *,int);
  70 #endif
  71 extern char * __must_check skip_spaces(const char *);
  72 
  73 extern char *strim(char *);
  74 
  75 static inline __must_check char *strstrip(char *str)
  76 {
  77         return strim(str);
  78 }
  79 
  80 #ifndef __HAVE_ARCH_STRSTR
  81 extern char * strstr(const char *, const char *);
  82 #endif
  83 #ifndef __HAVE_ARCH_STRNSTR
  84 extern char * strnstr(const char *, const char *, size_t);
  85 #endif
  86 #ifndef __HAVE_ARCH_STRLEN
  87 extern __kernel_size_t strlen(const char *);
  88 #endif
  89 #ifndef __HAVE_ARCH_STRNLEN
  90 extern __kernel_size_t strnlen(const char *,__kernel_size_t);
  91 #endif
  92 #ifndef __HAVE_ARCH_STRPBRK
  93 extern char * strpbrk(const char *,const char *);
  94 #endif
  95 #ifndef __HAVE_ARCH_STRSEP
  96 extern char * strsep(char **,const char *);
  97 #endif
  98 #ifndef __HAVE_ARCH_STRSPN
  99 extern __kernel_size_t strspn(const char *,const char *);
 100 #endif
 101 #ifndef __HAVE_ARCH_STRCSPN
 102 extern __kernel_size_t strcspn(const char *,const char *);
 103 #endif
 104 
 105 #ifndef __HAVE_ARCH_MEMSET
 106 extern void * memset(void *,int,__kernel_size_t);
 107 #endif
 108 
 109 #ifndef __HAVE_ARCH_MEMSET16
 110 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
 111 #endif
 112 
 113 #ifndef __HAVE_ARCH_MEMSET32
 114 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
 115 #endif
 116 
 117 #ifndef __HAVE_ARCH_MEMSET64
 118 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
 119 #endif
 120 
 121 static inline void *memset_l(unsigned long *p, unsigned long v,
 122                 __kernel_size_t n)
 123 {
 124         if (BITS_PER_LONG == 32)
 125                 return memset32((uint32_t *)p, v, n);
 126         else
 127                 return memset64((uint64_t *)p, v, n);
 128 }
 129 
 130 static inline void *memset_p(void **p, void *v, __kernel_size_t n)
 131 {
 132         if (BITS_PER_LONG == 32)
 133                 return memset32((uint32_t *)p, (uintptr_t)v, n);
 134         else
 135                 return memset64((uint64_t *)p, (uintptr_t)v, n);
 136 }
 137 
 138 extern void **__memcat_p(void **a, void **b);
 139 #define memcat_p(a, b) ({                                       \
 140         BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)),              \
 141                          "type mismatch in memcat_p()");        \
 142         (typeof(*a) *)__memcat_p((void **)(a), (void **)(b));   \
 143 })
 144 
 145 #ifndef __HAVE_ARCH_MEMCPY
 146 extern void * memcpy(void *,const void *,__kernel_size_t);
 147 #endif
 148 #ifndef __HAVE_ARCH_MEMMOVE
 149 extern void * memmove(void *,const void *,__kernel_size_t);
 150 #endif
 151 #ifndef __HAVE_ARCH_MEMSCAN
 152 extern void * memscan(void *,int,__kernel_size_t);
 153 #endif
 154 #ifndef __HAVE_ARCH_MEMCMP
 155 extern int memcmp(const void *,const void *,__kernel_size_t);
 156 #endif
 157 #ifndef __HAVE_ARCH_BCMP
 158 extern int bcmp(const void *,const void *,__kernel_size_t);
 159 #endif
 160 #ifndef __HAVE_ARCH_MEMCHR
 161 extern void * memchr(const void *,int,__kernel_size_t);
 162 #endif
 163 #ifndef __HAVE_ARCH_MEMCPY_MCSAFE
 164 static inline __must_check unsigned long memcpy_mcsafe(void *dst,
 165                 const void *src, size_t cnt)
 166 {
 167         memcpy(dst, src, cnt);
 168         return 0;
 169 }
 170 #endif
 171 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
 172 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
 173 {
 174         memcpy(dst, src, cnt);
 175 }
 176 #endif
 177 void *memchr_inv(const void *s, int c, size_t n);
 178 char *strreplace(char *s, char old, char new);
 179 
 180 extern void kfree_const(const void *x);
 181 
 182 extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
 183 extern const char *kstrdup_const(const char *s, gfp_t gfp);
 184 extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
 185 extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
 186 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
 187 
 188 extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
 189 extern void argv_free(char **argv);
 190 
 191 extern bool sysfs_streq(const char *s1, const char *s2);
 192 extern int kstrtobool(const char *s, bool *res);
 193 static inline int strtobool(const char *s, bool *res)
 194 {
 195         return kstrtobool(s, res);
 196 }
 197 
 198 int match_string(const char * const *array, size_t n, const char *string);
 199 int __sysfs_match_string(const char * const *array, size_t n, const char *s);
 200 
 201 /**
 202  * sysfs_match_string - matches given string in an array
 203  * @_a: array of strings
 204  * @_s: string to match with
 205  *
 206  * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
 207  */
 208 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
 209 
 210 #ifdef CONFIG_BINARY_PRINTF
 211 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
 212 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
 213 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
 214 #endif
 215 
 216 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
 217                                        const void *from, size_t available);
 218 
 219 /**
 220  * strstarts - does @str start with @prefix?
 221  * @str: string to examine
 222  * @prefix: prefix to look for.
 223  */
 224 static inline bool strstarts(const char *str, const char *prefix)
 225 {
 226         return strncmp(str, prefix, strlen(prefix)) == 0;
 227 }
 228 
 229 size_t memweight(const void *ptr, size_t bytes);
 230 
 231 /**
 232  * memzero_explicit - Fill a region of memory (e.g. sensitive
 233  *                    keying data) with 0s.
 234  * @s: Pointer to the start of the area.
 235  * @count: The size of the area.
 236  *
 237  * Note: usually using memset() is just fine (!), but in cases
 238  * where clearing out _local_ data at the end of a scope is
 239  * necessary, memzero_explicit() should be used instead in
 240  * order to prevent the compiler from optimising away zeroing.
 241  *
 242  * memzero_explicit() doesn't need an arch-specific version as
 243  * it just invokes the one of memset() implicitly.
 244  */
 245 static inline void memzero_explicit(void *s, size_t count)
 246 {
 247         memset(s, 0, count);
 248         barrier_data(s);
 249 }
 250 
 251 /**
 252  * kbasename - return the last part of a pathname.
 253  *
 254  * @path: path to extract the filename from.
 255  */
 256 static inline const char *kbasename(const char *path)
 257 {
 258         const char *tail = strrchr(path, '/');
 259         return tail ? tail + 1 : path;
 260 }
 261 
 262 #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
 263 #define __RENAME(x) __asm__(#x)
 264 
 265 void fortify_panic(const char *name) __noreturn __cold;
 266 void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
 267 void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
 268 void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter");
 269 void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
 270 
 271 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
 272 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
 273 {
 274         size_t p_size = __builtin_object_size(p, 0);
 275         if (__builtin_constant_p(size) && p_size < size)
 276                 __write_overflow();
 277         if (p_size < size)
 278                 fortify_panic(__func__);
 279         return __builtin_strncpy(p, q, size);
 280 }
 281 
 282 __FORTIFY_INLINE char *strcat(char *p, const char *q)
 283 {
 284         size_t p_size = __builtin_object_size(p, 0);
 285         if (p_size == (size_t)-1)
 286                 return __builtin_strcat(p, q);
 287         if (strlcat(p, q, p_size) >= p_size)
 288                 fortify_panic(__func__);
 289         return p;
 290 }
 291 
 292 __FORTIFY_INLINE __kernel_size_t strlen(const char *p)
 293 {
 294         __kernel_size_t ret;
 295         size_t p_size = __builtin_object_size(p, 0);
 296 
 297         /* Work around gcc excess stack consumption issue */
 298         if (p_size == (size_t)-1 ||
 299             (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
 300                 return __builtin_strlen(p);
 301         ret = strnlen(p, p_size);
 302         if (p_size <= ret)
 303                 fortify_panic(__func__);
 304         return ret;
 305 }
 306 
 307 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
 308 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
 309 {
 310         size_t p_size = __builtin_object_size(p, 0);
 311         __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
 312         if (p_size <= ret && maxlen != ret)
 313                 fortify_panic(__func__);
 314         return ret;
 315 }
 316 
 317 /* defined after fortified strlen to reuse it */
 318 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
 319 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
 320 {
 321         size_t ret;
 322         size_t p_size = __builtin_object_size(p, 0);
 323         size_t q_size = __builtin_object_size(q, 0);
 324         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 325                 return __real_strlcpy(p, q, size);
 326         ret = strlen(q);
 327         if (size) {
 328                 size_t len = (ret >= size) ? size - 1 : ret;
 329                 if (__builtin_constant_p(len) && len >= p_size)
 330                         __write_overflow();
 331                 if (len >= p_size)
 332                         fortify_panic(__func__);
 333                 __builtin_memcpy(p, q, len);
 334                 p[len] = '\0';
 335         }
 336         return ret;
 337 }
 338 
 339 /* defined after fortified strlen and strnlen to reuse them */
 340 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
 341 {
 342         size_t p_len, copy_len;
 343         size_t p_size = __builtin_object_size(p, 0);
 344         size_t q_size = __builtin_object_size(q, 0);
 345         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 346                 return __builtin_strncat(p, q, count);
 347         p_len = strlen(p);
 348         copy_len = strnlen(q, count);
 349         if (p_size < p_len + copy_len + 1)
 350                 fortify_panic(__func__);
 351         __builtin_memcpy(p + p_len, q, copy_len);
 352         p[p_len + copy_len] = '\0';
 353         return p;
 354 }
 355 
 356 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
 357 {
 358         size_t p_size = __builtin_object_size(p, 0);
 359         if (__builtin_constant_p(size) && p_size < size)
 360                 __write_overflow();
 361         if (p_size < size)
 362                 fortify_panic(__func__);
 363         return __builtin_memset(p, c, size);
 364 }
 365 
 366 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
 367 {
 368         size_t p_size = __builtin_object_size(p, 0);
 369         size_t q_size = __builtin_object_size(q, 0);
 370         if (__builtin_constant_p(size)) {
 371                 if (p_size < size)
 372                         __write_overflow();
 373                 if (q_size < size)
 374                         __read_overflow2();
 375         }
 376         if (p_size < size || q_size < size)
 377                 fortify_panic(__func__);
 378         return __builtin_memcpy(p, q, size);
 379 }
 380 
 381 __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
 382 {
 383         size_t p_size = __builtin_object_size(p, 0);
 384         size_t q_size = __builtin_object_size(q, 0);
 385         if (__builtin_constant_p(size)) {
 386                 if (p_size < size)
 387                         __write_overflow();
 388                 if (q_size < size)
 389                         __read_overflow2();
 390         }
 391         if (p_size < size || q_size < size)
 392                 fortify_panic(__func__);
 393         return __builtin_memmove(p, q, size);
 394 }
 395 
 396 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
 397 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
 398 {
 399         size_t p_size = __builtin_object_size(p, 0);
 400         if (__builtin_constant_p(size) && p_size < size)
 401                 __read_overflow();
 402         if (p_size < size)
 403                 fortify_panic(__func__);
 404         return __real_memscan(p, c, size);
 405 }
 406 
 407 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
 408 {
 409         size_t p_size = __builtin_object_size(p, 0);
 410         size_t q_size = __builtin_object_size(q, 0);
 411         if (__builtin_constant_p(size)) {
 412                 if (p_size < size)
 413                         __read_overflow();
 414                 if (q_size < size)
 415                         __read_overflow2();
 416         }
 417         if (p_size < size || q_size < size)
 418                 fortify_panic(__func__);
 419         return __builtin_memcmp(p, q, size);
 420 }
 421 
 422 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
 423 {
 424         size_t p_size = __builtin_object_size(p, 0);
 425         if (__builtin_constant_p(size) && p_size < size)
 426                 __read_overflow();
 427         if (p_size < size)
 428                 fortify_panic(__func__);
 429         return __builtin_memchr(p, c, size);
 430 }
 431 
 432 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
 433 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
 434 {
 435         size_t p_size = __builtin_object_size(p, 0);
 436         if (__builtin_constant_p(size) && p_size < size)
 437                 __read_overflow();
 438         if (p_size < size)
 439                 fortify_panic(__func__);
 440         return __real_memchr_inv(p, c, size);
 441 }
 442 
 443 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
 444 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
 445 {
 446         size_t p_size = __builtin_object_size(p, 0);
 447         if (__builtin_constant_p(size) && p_size < size)
 448                 __read_overflow();
 449         if (p_size < size)
 450                 fortify_panic(__func__);
 451         return __real_kmemdup(p, size, gfp);
 452 }
 453 
 454 /* defined after fortified strlen and memcpy to reuse them */
 455 __FORTIFY_INLINE char *strcpy(char *p, const char *q)
 456 {
 457         size_t p_size = __builtin_object_size(p, 0);
 458         size_t q_size = __builtin_object_size(q, 0);
 459         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 460                 return __builtin_strcpy(p, q);
 461         memcpy(p, q, strlen(q) + 1);
 462         return p;
 463 }
 464 
 465 #endif
 466 
 467 /**
 468  * memcpy_and_pad - Copy one buffer to another with padding
 469  * @dest: Where to copy to
 470  * @dest_len: The destination buffer size
 471  * @src: Where to copy from
 472  * @count: The number of bytes to copy
 473  * @pad: Character to use for padding if space is left in destination.
 474  */
 475 static inline void memcpy_and_pad(void *dest, size_t dest_len,
 476                                   const void *src, size_t count, int pad)
 477 {
 478         if (dest_len > count) {
 479                 memcpy(dest, src, count);
 480                 memset(dest + count, pad,  dest_len - count);
 481         } else
 482                 memcpy(dest, src, dest_len);
 483 }
 484 
 485 /**
 486  * str_has_prefix - Test if a string has a given prefix
 487  * @str: The string to test
 488  * @prefix: The string to see if @str starts with
 489  *
 490  * A common way to test a prefix of a string is to do:
 491  *  strncmp(str, prefix, sizeof(prefix) - 1)
 492  *
 493  * But this can lead to bugs due to typos, or if prefix is a pointer
 494  * and not a constant. Instead use str_has_prefix().
 495  *
 496  * Returns:
 497  * * strlen(@prefix) if @str starts with @prefix
 498  * * 0 if @str does not start with @prefix
 499  */
 500 static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
 501 {
 502         size_t len = strlen(prefix);
 503         return strncmp(str, prefix, len) == 0 ? len : 0;
 504 }
 505 
 506 #endif /* _LINUX_STRING_H_ */