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_MEMCHR
 146 extern void * memchr(const void *,int,__kernel_size_t);
 147 #endif
 148 #ifndef __HAVE_ARCH_MEMCPY_MCSAFE
 149 static inline __must_check int memcpy_mcsafe(void *dst, const void *src,
 150                 size_t cnt)
 151 {
 152         memcpy(dst, src, cnt);
 153         return 0;
 154 }
 155 #endif
 156 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
 157 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
 158 {
 159         memcpy(dst, src, cnt);
 160 }
 161 #endif
 162 void *memchr_inv(const void *s, int c, size_t n);
 163 char *strreplace(char *s, char old, char new);
 164
 165 extern void kfree_const(const void *x);
 166
 167 extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
 168 extern const char *kstrdup_const(const char *s, gfp_t gfp);
 169 extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
 170 extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
 171 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
 172
 173 extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
 174 extern void argv_free(char **argv);
 175
 176 extern bool sysfs_streq(const char *s1, const char *s2);
 177 extern int kstrtobool(const char *s, bool *res);
 178 static inline int strtobool(const char *s, bool *res)
 179 {
 180         return kstrtobool(s, res);
 181 }
 182
 183 int match_string(const char * const *array, size_t n, const char *string);
 184 int __sysfs_match_string(const char * const *array, size_t n, const char *s);
 185
 186 /**
 187  * sysfs_match_string - matches given string in an array
 188  * @_a: array of strings
 189  * @_s: string to match with
 190  *
 191  * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
 192  */
 193 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
 194
 195 #ifdef CONFIG_BINARY_PRINTF
 196 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
 197 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
 198 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
 199 #endif
 200
 201 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
 202                                        const void *from, size_t available);
 203
 204 /**
 205  * strstarts - does @str start with @prefix?
 206  * @str: string to examine
 207  * @prefix: prefix to look for.
 208  */
 209 static inline bool strstarts(const char *str, const char *prefix)
 210 {
 211         return strncmp(str, prefix, strlen(prefix)) == 0;
 212 }
 213
 214 size_t memweight(const void *ptr, size_t bytes);
 215 void memzero_explicit(void *s, size_t count);
 216
 217 /**
 218  * kbasename - return the last part of a pathname.
 219  *
 220  * @path: path to extract the filename from.
 221  */
 222 static inline const char *kbasename(const char *path)
 223 {
 224         const char *tail = strrchr(path, '/');
 225         return tail ? tail + 1 : path;
 226 }
 227
 228 #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
 229 #define __RENAME(x) __asm__(#x)
 230
 231 void fortify_panic(const char *name) __noreturn __cold;
 232 void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
 233 void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
 234 void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter");
 235 void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
 236
 237 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
 238 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
 239 {
 240         size_t p_size = __builtin_object_size(p, 0);
 241         if (__builtin_constant_p(size) && p_size < size)
 242                 __write_overflow();
 243         if (p_size < size)
 244                 fortify_panic(__func__);
 245         return __builtin_strncpy(p, q, size);
 246 }
 247
 248 __FORTIFY_INLINE char *strcat(char *p, const char *q)
 249 {
 250         size_t p_size = __builtin_object_size(p, 0);
 251         if (p_size == (size_t)-1)
 252                 return __builtin_strcat(p, q);
 253         if (strlcat(p, q, p_size) >= p_size)
 254                 fortify_panic(__func__);
 255         return p;
 256 }
 257
 258 __FORTIFY_INLINE __kernel_size_t strlen(const char *p)
 259 {
 260         __kernel_size_t ret;
 261         size_t p_size = __builtin_object_size(p, 0);
 262
 263         /* Work around gcc excess stack consumption issue */
 264         if (p_size == (size_t)-1 ||
 265             (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
 266                 return __builtin_strlen(p);
 267         ret = strnlen(p, p_size);
 268         if (p_size <= ret)
 269                 fortify_panic(__func__);
 270         return ret;
 271 }
 272
 273 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
 274 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
 275 {
 276         size_t p_size = __builtin_object_size(p, 0);
 277         __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
 278         if (p_size <= ret && maxlen != ret)
 279                 fortify_panic(__func__);
 280         return ret;
 281 }
 282
 283 /* defined after fortified strlen to reuse it */
 284 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
 285 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
 286 {
 287         size_t ret;
 288         size_t p_size = __builtin_object_size(p, 0);
 289         size_t q_size = __builtin_object_size(q, 0);
 290         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 291                 return __real_strlcpy(p, q, size);
 292         ret = strlen(q);
 293         if (size) {
 294                 size_t len = (ret >= size) ? size - 1 : ret;
 295                 if (__builtin_constant_p(len) && len >= p_size)
 296                         __write_overflow();
 297                 if (len >= p_size)
 298                         fortify_panic(__func__);
 299                 __builtin_memcpy(p, q, len);
 300                 p[len] = '\0';
 301         }
 302         return ret;
 303 }
 304
 305 /* defined after fortified strlen and strnlen to reuse them */
 306 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
 307 {
 308         size_t p_len, copy_len;
 309         size_t p_size = __builtin_object_size(p, 0);
 310         size_t q_size = __builtin_object_size(q, 0);
 311         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 312                 return __builtin_strncat(p, q, count);
 313         p_len = strlen(p);
 314         copy_len = strnlen(q, count);
 315         if (p_size < p_len + copy_len + 1)
 316                 fortify_panic(__func__);
 317         __builtin_memcpy(p + p_len, q, copy_len);
 318         p[p_len + copy_len] = '\0';
 319         return p;
 320 }
 321
 322 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
 323 {
 324         size_t p_size = __builtin_object_size(p, 0);
 325         if (__builtin_constant_p(size) && p_size < size)
 326                 __write_overflow();
 327         if (p_size < size)
 328                 fortify_panic(__func__);
 329         return __builtin_memset(p, c, size);
 330 }
 331
 332 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
 333 {
 334         size_t p_size = __builtin_object_size(p, 0);
 335         size_t q_size = __builtin_object_size(q, 0);
 336         if (__builtin_constant_p(size)) {
 337                 if (p_size < size)
 338                         __write_overflow();
 339                 if (q_size < size)
 340                         __read_overflow2();
 341         }
 342         if (p_size < size || q_size < size)
 343                 fortify_panic(__func__);
 344         return __builtin_memcpy(p, q, size);
 345 }
 346
 347 __FORTIFY_INLINE void *memmove(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_memmove(p, q, size);
 360 }
 361
 362 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
 363 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
 364 {
 365         size_t p_size = __builtin_object_size(p, 0);
 366         if (__builtin_constant_p(size) && p_size < size)
 367                 __read_overflow();
 368         if (p_size < size)
 369                 fortify_panic(__func__);
 370         return __real_memscan(p, c, size);
 371 }
 372
 373 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
 374 {
 375         size_t p_size = __builtin_object_size(p, 0);
 376         size_t q_size = __builtin_object_size(q, 0);
 377         if (__builtin_constant_p(size)) {
 378                 if (p_size < size)
 379                         __read_overflow();
 380                 if (q_size < size)
 381                         __read_overflow2();
 382         }
 383         if (p_size < size || q_size < size)
 384                 fortify_panic(__func__);
 385         return __builtin_memcmp(p, q, size);
 386 }
 387
 388 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
 389 {
 390         size_t p_size = __builtin_object_size(p, 0);
 391         if (__builtin_constant_p(size) && p_size < size)
 392                 __read_overflow();
 393         if (p_size < size)
 394                 fortify_panic(__func__);
 395         return __builtin_memchr(p, c, size);
 396 }
 397
 398 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
 399 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
 400 {
 401         size_t p_size = __builtin_object_size(p, 0);
 402         if (__builtin_constant_p(size) && p_size < size)
 403                 __read_overflow();
 404         if (p_size < size)
 405                 fortify_panic(__func__);
 406         return __real_memchr_inv(p, c, size);
 407 }
 408
 409 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
 410 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
 411 {
 412         size_t p_size = __builtin_object_size(p, 0);
 413         if (__builtin_constant_p(size) && p_size < size)
 414                 __read_overflow();
 415         if (p_size < size)
 416                 fortify_panic(__func__);
 417         return __real_kmemdup(p, size, gfp);
 418 }
 419
 420 /* defined after fortified strlen and memcpy to reuse them */
 421 __FORTIFY_INLINE char *strcpy(char *p, const char *q)
 422 {
 423         size_t p_size = __builtin_object_size(p, 0);
 424         size_t q_size = __builtin_object_size(q, 0);
 425         if (p_size == (size_t)-1 && q_size == (size_t)-1)
 426                 return __builtin_strcpy(p, q);
 427         memcpy(p, q, strlen(q) + 1);
 428         return p;
 429 }
 430
 431 #endif
 432
 433 /**
 434  * memcpy_and_pad - Copy one buffer to another with padding
 435  * @dest: Where to copy to
 436  * @dest_len: The destination buffer size
 437  * @src: Where to copy from
 438  * @count: The number of bytes to copy
 439  * @pad: Character to use for padding if space is left in destination.
 440  */
 441 static inline void memcpy_and_pad(void *dest, size_t dest_len,
 442                                   const void *src, size_t count, int pad)
 443 {
 444         if (dest_len > count) {
 445                 memcpy(dest, src, count);
 446                 memset(dest + count, pad,  dest_len - count);
 447         } else
 448                 memcpy(dest, src, dest_len);
 449 }
 450
 451 #endif /* _LINUX_STRING_H_ */