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#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
253#include <linux/fortify-string.h>
254#endif
255#ifndef unsafe_memcpy
256#define unsafe_memcpy(dst, src, bytes, justification) \
257 memcpy(dst, src, bytes)
258#endif
259
260void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
261 int pad);
262
263/**
264 * memset_after - Set a value after a struct member to the end of a struct
265 *
266 * @obj: Address of target struct instance
267 * @v: Byte value to repeatedly write
268 * @member: after which struct member to start writing bytes
269 *
270 * This is good for clearing padding following the given member.
271 */
272#define memset_after(obj, v, member) \
273({ \
274 u8 *__ptr = (u8 *)(obj); \
275 typeof(v) __val = (v); \
276 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \
277 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \
278})
279
280/**
281 * memset_startat - Set a value starting at a member to the end of a struct
282 *
283 * @obj: Address of target struct instance
284 * @v: Byte value to repeatedly write
285 * @member: struct member to start writing at
286 *
287 * Note that if there is padding between the prior member and the target
288 * member, memset_after() should be used to clear the prior padding.
289 */
290#define memset_startat(obj, v, member) \
291({ \
292 u8 *__ptr = (u8 *)(obj); \
293 typeof(v) __val = (v); \
294 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \
295 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \
296})
297
298/**
299 * str_has_prefix - Test if a string has a given prefix
300 * @str: The string to test
301 * @prefix: The string to see if @str starts with
302 *
303 * A common way to test a prefix of a string is to do:
304 * strncmp(str, prefix, sizeof(prefix) - 1)
305 *
306 * But this can lead to bugs due to typos, or if prefix is a pointer
307 * and not a constant. Instead use str_has_prefix().
308 *
309 * Returns:
310 * * strlen(@prefix) if @str starts with @prefix
311 * * 0 if @str does not start with @prefix
312 */
313static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
314{
315 size_t len = strlen(prefix);
316 return strncmp(str, prefix, len) == 0 ? len : 0;
317}
318
319#endif /* _LINUX_STRING_H_ */
320

source code of linux/include/linux/string.h