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