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 *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 void memzero_explicit(void *s, size_t count);
 231
 232 /**
 233  * kbasename - return the last part of a pathname.
 234  *
 235  * @path: path to extract the filename from.
 236  */
 237 static inline const char *kbasename(const char *path)
 238 {
 239         const char *tail = strrchr(path, '/');
 240         return tail ? tail + 1 : path;
 241 }
 242
 243 #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
 244 #define __RENAME(x) __asm__(#x)
 245
 246 void fortify_panic(const char *name) __noreturn __cold;
 247 void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
 248 void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
 249 void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter");
 250 void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
 251
 252 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
 253 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
 254 {
 255         size_t p_size = __builtin_object_size(p, 0);
 256         if (__builtin_constant_p(size) && p_size < size)
 257                 __write_overflow();
 258         if (p_size < size)
 259                 fortify_panic(__func__);
 260         return __builtin_strncpy(p, q, size);
 261 }
 262
 263 __FORTIFY_INLINE char *strcat(char *p, const char *q)
 264 {
 265         size_t p_size = __builtin_object_size(p, 0);
 266         if (p_size == (size_t)-1)
 267                 return __builtin_strcat(p, q);
 268         if (strlcat(p, q, p_size) >= p_size)
 269                 fortify_panic(__func__);
 270         return p;
 271 }
 272
 273 __FORTIFY_INLINE __kernel_size_t strlen(const char *p)
 274 {
 275         __kernel_size_t ret;
 276         size_t p_size = __builtin_object_size(p, 0);
 277
 278         /* Work around gcc excess stack consumption issue */
 279         if (p_size == (size_t)-1 ||
 280             (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
 281                 return __builtin_strlen(p);
 282         ret = strnlen(p, p_size);
 283         if (p_size <= ret)
 284                 fortify_panic(__func__);
 285         return ret;
 286 }
 287
 288 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
 289 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
 290 {
 291         size_t p_size = __builtin_object_size(p, 0);
 292         __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
 293         if (p_size <= ret && maxlen != ret)
 294                 fortify_panic(__func__);
 295         return ret;
 296 }
 297
 298 /* defined after fortified strlen to reuse it */
 299 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
 300 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
 301 {
 302         size_t ret;
 303         size_t p_size = __builtin_object_size(p, 0);
 304         size_t q_size = __builtin_object_size(q, 0);
 305         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 306                 return __real_strlcpy(p, q, size);
 307         ret = strlen(q);
 308         if (size) {
 309                 size_t len = (ret >= size) ? size - 1 : ret;
 310                 if (__builtin_constant_p(len) && len >= p_size)
 311                         __write_overflow();
 312                 if (len >= p_size)
 313                         fortify_panic(__func__);
 314                 __builtin_memcpy(p, q, len);
 315                 p[len] = '\0';
 316         }
 317         return ret;
 318 }
 319
 320 /* defined after fortified strlen and strnlen to reuse them */
 321 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
 322 {
 323         size_t p_len, copy_len;
 324         size_t p_size = __builtin_object_size(p, 0);
 325         size_t q_size = __builtin_object_size(q, 0);
 326         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 327                 return __builtin_strncat(p, q, count);
 328         p_len = strlen(p);
 329         copy_len = strnlen(q, count);
 330         if (p_size < p_len + copy_len + 1)
 331                 fortify_panic(__func__);
 332         __builtin_memcpy(p + p_len, q, copy_len);
 333         p[p_len + copy_len] = '\0';
 334         return p;
 335 }
 336
 337 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
 338 {
 339         size_t p_size = __builtin_object_size(p, 0);
 340         if (__builtin_constant_p(size) && p_size < size)
 341                 __write_overflow();
 342         if (p_size < size)
 343                 fortify_panic(__func__);
 344         return __builtin_memset(p, c, size);
 345 }
 346
 347 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
 348 {
 349         size_t p_size = __builtin_object_size(p, 0);
 350         size_t q_size = __builtin_object_size(q, 0);
 351         if (__builtin_constant_p(size)) {
 352                 if (p_size < size)
 353                         __write_overflow();
 354                 if (q_size < size)
 355                         __read_overflow2();
 356         }
 357         if (p_size < size || q_size < size)
 358                 fortify_panic(__func__);
 359         return __builtin_memcpy(p, q, size);
 360 }
 361
 362 __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
 363 {
 364         size_t p_size = __builtin_object_size(p, 0);
 365         size_t q_size = __builtin_object_size(q, 0);
 366         if (__builtin_constant_p(size)) {
 367                 if (p_size < size)
 368                         __write_overflow();
 369                 if (q_size < size)
 370                         __read_overflow2();
 371         }
 372         if (p_size < size || q_size < size)
 373                 fortify_panic(__func__);
 374         return __builtin_memmove(p, q, size);
 375 }
 376
 377 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
 378 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
 379 {
 380         size_t p_size = __builtin_object_size(p, 0);
 381         if (__builtin_constant_p(size) && p_size < size)
 382                 __read_overflow();
 383         if (p_size < size)
 384                 fortify_panic(__func__);
 385         return __real_memscan(p, c, size);
 386 }
 387
 388 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
 389 {
 390         size_t p_size = __builtin_object_size(p, 0);
 391         size_t q_size = __builtin_object_size(q, 0);
 392         if (__builtin_constant_p(size)) {
 393                 if (p_size < size)
 394                         __read_overflow();
 395                 if (q_size < size)
 396                         __read_overflow2();
 397         }
 398         if (p_size < size || q_size < size)
 399                 fortify_panic(__func__);
 400         return __builtin_memcmp(p, q, size);
 401 }
 402
 403 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
 404 {
 405         size_t p_size = __builtin_object_size(p, 0);
 406         if (__builtin_constant_p(size) && p_size < size)
 407                 __read_overflow();
 408         if (p_size < size)
 409                 fortify_panic(__func__);
 410         return __builtin_memchr(p, c, size);
 411 }
 412
 413 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
 414 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
 415 {
 416         size_t p_size = __builtin_object_size(p, 0);
 417         if (__builtin_constant_p(size) && p_size < size)
 418                 __read_overflow();
 419         if (p_size < size)
 420                 fortify_panic(__func__);
 421         return __real_memchr_inv(p, c, size);
 422 }
 423
 424 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
 425 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
 426 {
 427         size_t p_size = __builtin_object_size(p, 0);
 428         if (__builtin_constant_p(size) && p_size < size)
 429                 __read_overflow();
 430         if (p_size < size)
 431                 fortify_panic(__func__);
 432         return __real_kmemdup(p, size, gfp);
 433 }
 434
 435 /* defined after fortified strlen and memcpy to reuse them */
 436 __FORTIFY_INLINE char *strcpy(char *p, const char *q)
 437 {
 438         size_t p_size = __builtin_object_size(p, 0);
 439         size_t q_size = __builtin_object_size(q, 0);
 440         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 441                 return __builtin_strcpy(p, q);
 442         memcpy(p, q, strlen(q) + 1);
 443         return p;
 444 }
 445
 446 #endif
 447
 448 /**
 449  * memcpy_and_pad - Copy one buffer to another with padding
 450  * @dest: Where to copy to
 451  * @dest_len: The destination buffer size
 452  * @src: Where to copy from
 453  * @count: The number of bytes to copy
 454  * @pad: Character to use for padding if space is left in destination.
 455  */
 456 static inline void memcpy_and_pad(void *dest, size_t dest_len,
 457                                   const void *src, size_t count, int pad)
 458 {
 459         if (dest_len > count) {
 460                 memcpy(dest, src, count);
 461                 memset(dest + count, pad,  dest_len - count);
 462         } else
 463                 memcpy(dest, src, dest_len);
 464 }
 465
 466 /**
 467  * str_has_prefix - Test if a string has a given prefix
 468  * @str: The string to test
 469  * @prefix: The string to see if @str starts with
 470  *
 471  * A common way to test a prefix of a string is to do:
 472  *  strncmp(str, prefix, sizeof(prefix) - 1)
 473  *
 474  * But this can lead to bugs due to typos, or if prefix is a pointer
 475  * and not a constant. Instead use str_has_prefix().
 476  *
 477  * Returns:
 478  * * strlen(@prefix) if @str starts with @prefix
 479  * * 0 if @str does not start with @prefix
 480  */
 481 static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
 482 {
 483         size_t len = strlen(prefix);
 484         return strncmp(str, prefix, len) == 0 ? len : 0;
 485 }
 486
 487 #endif /* _LINUX_STRING_H_ */