LXR linux/include/linux/string.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_STRING_H_
   3#define _LINUX_STRING_H_
   4
   5#include <linux/compiler.h>     /* for inline */
   6#include <linux/types.h>        /* for size_t */
   7#include <linux/stddef.h>       /* for NULL */
   8#include <linux/errno.h>        /* for E2BIG */
   9#include <linux/stdarg.h>
  10#include <uapi/linux/string.h>
  11
  12extern char *strndup_user(const char __user *, long);
  13extern void *memdup_user(const void __user *, size_t);
  14extern void *vmemdup_user(const void __user *, size_t);
  15extern 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
  23extern char * strcpy(char *,const char *);
  24#endif
  25#ifndef __HAVE_ARCH_STRNCPY
  26extern char * strncpy(char *,const char *, __kernel_size_t);
  27#endif
  28#ifndef __HAVE_ARCH_STRLCPY
  29size_t strlcpy(char *, const char *, size_t);
  30#endif
  31#ifndef __HAVE_ARCH_STRSCPY
  32ssize_t strscpy(char *, const char *, size_t);
  33#endif
  34
  35/* Wraps calls to strscpy()/memset(), no arch specific code required */
  36ssize_t strscpy_pad(char *dest, const char *src, size_t count);
  37
  38#ifndef __HAVE_ARCH_STRCAT
  39extern char * strcat(char *, const char *);
  40#endif
  41#ifndef __HAVE_ARCH_STRNCAT
  42extern char * strncat(char *, const char *, __kernel_size_t);
  43#endif
  44#ifndef __HAVE_ARCH_STRLCAT
  45extern size_t strlcat(char *, const char *, __kernel_size_t);
  46#endif
  47#ifndef __HAVE_ARCH_STRCMP
  48extern int strcmp(const char *,const char *);
  49#endif
  50#ifndef __HAVE_ARCH_STRNCMP
  51extern int strncmp(const char *,const char *,__kernel_size_t);
  52#endif
  53#ifndef __HAVE_ARCH_STRCASECMP
  54extern int strcasecmp(const char *s1, const char *s2);
  55#endif
  56#ifndef __HAVE_ARCH_STRNCASECMP
  57extern int strncasecmp(const char *s1, const char *s2, size_t n);
  58#endif
  59#ifndef __HAVE_ARCH_STRCHR
  60extern char * strchr(const char *,int);
  61#endif
  62#ifndef __HAVE_ARCH_STRCHRNUL
  63extern char * strchrnul(const char *,int);
  64#endif
  65extern char * strnchrnul(const char *, size_t, int);
  66#ifndef __HAVE_ARCH_STRNCHR
  67extern char * strnchr(const char *, size_t, int);
  68#endif
  69#ifndef __HAVE_ARCH_STRRCHR
  70extern char * strrchr(const char *,int);
  71#endif
  72extern char * __must_check skip_spaces(const char *);
  73
  74extern char *strim(char *);
  75
  76static inline __must_check char *strstrip(char *str)
  77{
  78        return strim(str);
  79}
  80
  81#ifndef __HAVE_ARCH_STRSTR
  82extern char * strstr(const char *, const char *);
  83#endif
  84#ifndef __HAVE_ARCH_STRNSTR
  85extern char * strnstr(const char *, const char *, size_t);
  86#endif
  87#ifndef __HAVE_ARCH_STRLEN
  88extern __kernel_size_t strlen(const char *);
  89#endif
  90#ifndef __HAVE_ARCH_STRNLEN
  91extern __kernel_size_t strnlen(const char *,__kernel_size_t);
  92#endif
  93#ifndef __HAVE_ARCH_STRPBRK
  94extern char * strpbrk(const char *,const char *);
  95#endif
  96#ifndef __HAVE_ARCH_STRSEP
  97extern char * strsep(char **,const char *);
  98#endif
  99#ifndef __HAVE_ARCH_STRSPN
 100extern __kernel_size_t strspn(const char *,const char *);
 101#endif
 102#ifndef __HAVE_ARCH_STRCSPN
 103extern __kernel_size_t strcspn(const char *,const char *);
 104#endif
 105
 106#ifndef __HAVE_ARCH_MEMSET
 107extern void * memset(void *,int,__kernel_size_t);
 108#endif
 109
 110#ifndef __HAVE_ARCH_MEMSET16
 111extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
 112#endif
 113
 114#ifndef __HAVE_ARCH_MEMSET32
 115extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
 116#endif
 117
 118#ifndef __HAVE_ARCH_MEMSET64
 119extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
 120#endif
 121
 122static inline void *memset_l(unsigned long *p, unsigned long v,
 123                __kernel_size_t n)
 124{
 125        if (BITS_PER_LONG == 32)
 126                return memset32((uint32_t *)p, v, n);
 127        else
 128                return memset64((uint64_t *)p, v, n);
 129}
 130
 131static inline void *memset_p(void **p, void *v, __kernel_size_t n)
 132{
 133        if (BITS_PER_LONG == 32)
 134                return memset32((uint32_t *)p, (uintptr_t)v, n);
 135        else
 136                return memset64((uint64_t *)p, (uintptr_t)v, n);
 137}
 138
 139extern void **__memcat_p(void **a, void **b);
 140#define memcat_p(a, b) ({                                       \
 141        BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)),              \
 142                         "type mismatch in memcat_p()");        \
 143        (typeof(*a) *)__memcat_p((void **)(a), (void **)(b));   \
 144})
 145
 146#ifndef __HAVE_ARCH_MEMCPY
 147extern void * memcpy(void *,const void *,__kernel_size_t);
 148#endif
 149#ifndef __HAVE_ARCH_MEMMOVE
 150extern void * memmove(void *,const void *,__kernel_size_t);
 151#endif
 152#ifndef __HAVE_ARCH_MEMSCAN
 153extern void * memscan(void *,int,__kernel_size_t);
 154#endif
 155#ifndef __HAVE_ARCH_MEMCMP
 156extern int memcmp(const void *,const void *,__kernel_size_t);
 157#endif
 158#ifndef __HAVE_ARCH_BCMP
 159extern int bcmp(const void *,const void *,__kernel_size_t);
 160#endif
 161#ifndef __HAVE_ARCH_MEMCHR
 162extern void * memchr(const void *,int,__kernel_size_t);
 163#endif
 164#ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
 165static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
 166{
 167        memcpy(dst, src, cnt);
 168}
 169#endif
 170
 171void *memchr_inv(const void *s, int c, size_t n);
 172char *strreplace(char *s, char old, char new);
 173
 174extern void kfree_const(const void *x);
 175
 176extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
 177extern const char *kstrdup_const(const char *s, gfp_t gfp);
 178extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
 179extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
 180extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
 181
 182extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
 183extern void argv_free(char **argv);
 184
 185extern bool sysfs_streq(const char *s1, const char *s2);
 186int match_string(const char * const *array, size_t n, const char *string);
 187int __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
 199int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
 200int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
 201int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
 202#endif
 203
 204extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
 205                                       const void *from, size_t available);
 206
 207int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
 208
 209/**
 210 * strstarts - does @str start with @prefix?
 211 * @str: string to examine
 212 * @prefix: prefix to look for.
 213 */
 214static inline bool strstarts(const char *str, const char *prefix)
 215{
 216        return strncmp(str, prefix, strlen(prefix)) == 0;
 217}
 218
 219size_t memweight(const void *ptr, size_t bytes);
 220
 221/**
 222 * memzero_explicit - Fill a region of memory (e.g. sensitive
 223 *                    keying data) with 0s.
 224 * @s: Pointer to the start of the area.
 225 * @count: The size of the area.
 226 *
 227 * Note: usually using memset() is just fine (!), but in cases
 228 * where clearing out _local_ data at the end of a scope is
 229 * necessary, memzero_explicit() should be used instead in
 230 * order to prevent the compiler from optimising away zeroing.
 231 *
 232 * memzero_explicit() doesn't need an arch-specific version as
 233 * it just invokes the one of memset() implicitly.
 234 */
 235static inline void memzero_explicit(void *s, size_t count)
 236{
 237        memset(s, 0, count);
 238        barrier_data(s);
 239}
 240
 241/**
 242 * kbasename - return the last part of a pathname.
 243 *
 244 * @path: path to extract the filename from.
 245 */
 246static inline const char *kbasename(const char *path)
 247{
 248        const char *tail = strrchr(path, '/');
 249        return tail ? tail + 1 : path;
 250}
 251
 252#define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
 253#define __RENAME(x) __asm__(#x)
 254
 255void fortify_panic(const char *name) __noreturn __cold;
 256void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
 257void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
 258void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter");
 259void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
 260
 261#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
 262#include <linux/fortify-string.h>
 263#endif
 264
 265/**
 266 * memcpy_and_pad - Copy one buffer to another with padding
 267 * @dest: Where to copy to
 268 * @dest_len: The destination buffer size
 269 * @src: Where to copy from
 270 * @count: The number of bytes to copy
 271 * @pad: Character to use for padding if space is left in destination.
 272 */
 273static inline void memcpy_and_pad(void *dest, size_t dest_len,
 274                                  const void *src, size_t count, int pad)
 275{
 276        if (dest_len > count) {
 277                memcpy(dest, src, count);
 278                memset(dest + count, pad,  dest_len - count);
 279        } else
 280                memcpy(dest, src, dest_len);
 281}
 282
 283/**
 284 * str_has_prefix - Test if a string has a given prefix
 285 * @str: The string to test
 286 * @prefix: The string to see if @str starts with
 287 *
 288 * A common way to test a prefix of a string is to do:
 289 *  strncmp(str, prefix, sizeof(prefix) - 1)
 290 *
 291 * But this can lead to bugs due to typos, or if prefix is a pointer
 292 * and not a constant. Instead use str_has_prefix().
 293 *
 294 * Returns:
 295 * * strlen(@prefix) if @str starts with @prefix
 296 * * 0 if @str does not start with @prefix
 297 */
 298static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
 299{
 300        size_t len = strlen(prefix);
 301        return strncmp(str, prefix, len) == 0 ? len : 0;
 302}
 303
 304#endif /* _LINUX_STRING_H_ */
 305