Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
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linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_STRING_H_
3#define _LINUX_STRING_H_
4
5#include <linux/array_size.h>
6#include <linux/compiler.h> /* for inline */
7#include <linux/types.h> /* for size_t */
8#include <linux/stddef.h> /* for NULL */
9#include <linux/err.h> /* for ERR_PTR() */
10#include <linux/errno.h> /* for E2BIG */
11#include <linux/overflow.h> /* for check_mul_overflow() */
12#include <linux/stdarg.h>
13#include <uapi/linux/string.h>
14
15extern char *strndup_user(const char __user *, long);
16extern void *memdup_user(const void __user *, size_t);
17extern void *vmemdup_user(const void __user *, size_t);
18extern void *memdup_user_nul(const void __user *, size_t);
19
20/**
21 * memdup_array_user - duplicate array from user space
22 * @src: source address in user space
23 * @n: number of array members to copy
24 * @size: size of one array member
25 *
26 * Return: an ERR_PTR() on failure. Result is physically
27 * contiguous, to be freed by kfree().
28 */
29static inline void *memdup_array_user(const void __user *src, size_t n, size_t size)
30{
31 size_t nbytes;
32
33 if (check_mul_overflow(n, size, &nbytes))
34 return ERR_PTR(-EOVERFLOW);
35
36 return memdup_user(src, nbytes);
37}
38
39/**
40 * vmemdup_array_user - duplicate array from user space
41 * @src: source address in user space
42 * @n: number of array members to copy
43 * @size: size of one array member
44 *
45 * Return: an ERR_PTR() on failure. Result may be not
46 * physically contiguous. Use kvfree() to free.
47 */
48static inline void *vmemdup_array_user(const void __user *src, size_t n, size_t size)
49{
50 size_t nbytes;
51
52 if (check_mul_overflow(n, size, &nbytes))
53 return ERR_PTR(-EOVERFLOW);
54
55 return vmemdup_user(src, nbytes);
56}
57
58/*
59 * Include machine specific inline routines
60 */
61#include <asm/string.h>
62
63#ifndef __HAVE_ARCH_STRCPY
64extern char * strcpy(char *,const char *);
65#endif
66#ifndef __HAVE_ARCH_STRNCPY
67extern char * strncpy(char *,const char *, __kernel_size_t);
68#endif
69#ifndef __HAVE_ARCH_STRSCPY
70ssize_t strscpy(char *, const char *, size_t);
71#endif
72
73/* Wraps calls to strscpy()/memset(), no arch specific code required */
74ssize_t strscpy_pad(char *dest, const char *src, size_t count);
75
76#ifndef __HAVE_ARCH_STRCAT
77extern char * strcat(char *, const char *);
78#endif
79#ifndef __HAVE_ARCH_STRNCAT
80extern char * strncat(char *, const char *, __kernel_size_t);
81#endif
82#ifndef __HAVE_ARCH_STRLCAT
83extern size_t strlcat(char *, const char *, __kernel_size_t);
84#endif
85#ifndef __HAVE_ARCH_STRCMP
86extern int strcmp(const char *,const char *);
87#endif
88#ifndef __HAVE_ARCH_STRNCMP
89extern int strncmp(const char *,const char *,__kernel_size_t);
90#endif
91#ifndef __HAVE_ARCH_STRCASECMP
92extern int strcasecmp(const char *s1, const char *s2);
93#endif
94#ifndef __HAVE_ARCH_STRNCASECMP
95extern int strncasecmp(const char *s1, const char *s2, size_t n);
96#endif
97#ifndef __HAVE_ARCH_STRCHR
98extern char * strchr(const char *,int);
99#endif
100#ifndef __HAVE_ARCH_STRCHRNUL
101extern char * strchrnul(const char *,int);
102#endif
103extern char * strnchrnul(const char *, size_t, int);
104#ifndef __HAVE_ARCH_STRNCHR
105extern char * strnchr(const char *, size_t, int);
106#endif
107#ifndef __HAVE_ARCH_STRRCHR
108extern char * strrchr(const char *,int);
109#endif
110extern char * __must_check skip_spaces(const char *);
111
112extern char *strim(char *);
113
114static inline __must_check char *strstrip(char *str)
115{
116 return strim(str);
117}
118
119#ifndef __HAVE_ARCH_STRSTR
120extern char * strstr(const char *, const char *);
121#endif
122#ifndef __HAVE_ARCH_STRNSTR
123extern char * strnstr(const char *, const char *, size_t);
124#endif
125#ifndef __HAVE_ARCH_STRLEN
126extern __kernel_size_t strlen(const char *);
127#endif
128#ifndef __HAVE_ARCH_STRNLEN
129extern __kernel_size_t strnlen(const char *,__kernel_size_t);
130#endif
131#ifndef __HAVE_ARCH_STRPBRK
132extern char * strpbrk(const char *,const char *);
133#endif
134#ifndef __HAVE_ARCH_STRSEP
135extern char * strsep(char **,const char *);
136#endif
137#ifndef __HAVE_ARCH_STRSPN
138extern __kernel_size_t strspn(const char *,const char *);
139#endif
140#ifndef __HAVE_ARCH_STRCSPN
141extern __kernel_size_t strcspn(const char *,const char *);
142#endif
143
144#ifndef __HAVE_ARCH_MEMSET
145extern void * memset(void *,int,__kernel_size_t);
146#endif
147
148#ifndef __HAVE_ARCH_MEMSET16
149extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
150#endif
151
152#ifndef __HAVE_ARCH_MEMSET32
153extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
154#endif
155
156#ifndef __HAVE_ARCH_MEMSET64
157extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
158#endif
159
160static inline void *memset_l(unsigned long *p, unsigned long v,
161 __kernel_size_t n)
162{
163 if (BITS_PER_LONG == 32)
164 return memset32((uint32_t *)p, v, n);
165 else
166 return memset64((uint64_t *)p, v, n);
167}
168
169static inline void *memset_p(void **p, void *v, __kernel_size_t n)
170{
171 if (BITS_PER_LONG == 32)
172 return memset32((uint32_t *)p, (uintptr_t)v, n);
173 else
174 return memset64((uint64_t *)p, (uintptr_t)v, n);
175}
176
177extern void **__memcat_p(void **a, void **b);
178#define memcat_p(a, b) ({ \
179 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \
180 "type mismatch in memcat_p()"); \
181 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \
182})
183
184#ifndef __HAVE_ARCH_MEMCPY
185extern void * memcpy(void *,const void *,__kernel_size_t);
186#endif
187#ifndef __HAVE_ARCH_MEMMOVE
188extern void * memmove(void *,const void *,__kernel_size_t);
189#endif
190#ifndef __HAVE_ARCH_MEMSCAN
191extern void * memscan(void *,int,__kernel_size_t);
192#endif
193#ifndef __HAVE_ARCH_MEMCMP
194extern int memcmp(const void *,const void *,__kernel_size_t);
195#endif
196#ifndef __HAVE_ARCH_BCMP
197extern int bcmp(const void *,const void *,__kernel_size_t);
198#endif
199#ifndef __HAVE_ARCH_MEMCHR
200extern void * memchr(const void *,int,__kernel_size_t);
201#endif
202#ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
203static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
204{
205 memcpy(dst, src, cnt);
206}
207#endif
208
209void *memchr_inv(const void *s, int c, size_t n);
210char *strreplace(char *str, char old, char new);
211
212extern void kfree_const(const void *x);
213
214extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
215extern const char *kstrdup_const(const char *s, gfp_t gfp);
216extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
217extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
218extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
219extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
220
221extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
222extern void argv_free(char **argv);
223
224extern bool sysfs_streq(const char *s1, const char *s2);
225int match_string(const char * const *array, size_t n, const char *string);
226int __sysfs_match_string(const char * const *array, size_t n, const char *s);
227
228/**
229 * sysfs_match_string - matches given string in an array
230 * @_a: array of strings
231 * @_s: string to match with
232 *
233 * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
234 */
235#define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
236
237#ifdef CONFIG_BINARY_PRINTF
238int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
239int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
240int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
241#endif
242
243extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
244 const void *from, size_t available);
245
246int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
247
248/**
249 * strstarts - does @str start with @prefix?
250 * @str: string to examine
251 * @prefix: prefix to look for.
252 */
253static inline bool strstarts(const char *str, const char *prefix)
254{
255 return strncmp(str, prefix, strlen(prefix)) == 0;
256}
257
258size_t memweight(const void *ptr, size_t bytes);
259
260/**
261 * memzero_explicit - Fill a region of memory (e.g. sensitive
262 * keying data) with 0s.
263 * @s: Pointer to the start of the area.
264 * @count: The size of the area.
265 *
266 * Note: usually using memset() is just fine (!), but in cases
267 * where clearing out _local_ data at the end of a scope is
268 * necessary, memzero_explicit() should be used instead in
269 * order to prevent the compiler from optimising away zeroing.
270 *
271 * memzero_explicit() doesn't need an arch-specific version as
272 * it just invokes the one of memset() implicitly.
273 */
274static inline void memzero_explicit(void *s, size_t count)
275{
276 memset(s, 0, count);
277 barrier_data(s);
278}
279
280/**
281 * kbasename - return the last part of a pathname.
282 *
283 * @path: path to extract the filename from.
284 */
285static inline const char *kbasename(const char *path)
286{
287 const char *tail = strrchr(path, '/');
288 return tail ? tail + 1 : path;
289}
290
291#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
292#include <linux/fortify-string.h>
293#endif
294#ifndef unsafe_memcpy
295#define unsafe_memcpy(dst, src, bytes, justification) \
296 memcpy(dst, src, bytes)
297#endif
298
299void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
300 int pad);
301
302/**
303 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer
304 *
305 * @dest: Pointer of destination character array (marked as __nonstring)
306 * @src: Pointer to NUL-terminated string
307 * @pad: Padding character to fill any remaining bytes of @dest after copy
308 *
309 * This is a replacement for strncpy() uses where the destination is not
310 * a NUL-terminated string, but with bounds checking on the source size, and
311 * an explicit padding character. If padding is not required, use strtomem().
312 *
313 * Note that the size of @dest is not an argument, as the length of @dest
314 * must be discoverable by the compiler.
315 */
316#define strtomem_pad(dest, src, pad) do { \
317 const size_t _dest_len = __builtin_object_size(dest, 1); \
318 const size_t _src_len = __builtin_object_size(src, 1); \
319 \
320 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
321 _dest_len == (size_t)-1); \
322 memcpy_and_pad(dest, _dest_len, src, \
323 strnlen(src, min(_src_len, _dest_len)), pad); \
324} while (0)
325
326/**
327 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer
328 *
329 * @dest: Pointer of destination character array (marked as __nonstring)
330 * @src: Pointer to NUL-terminated string
331 *
332 * This is a replacement for strncpy() uses where the destination is not
333 * a NUL-terminated string, but with bounds checking on the source size, and
334 * without trailing padding. If padding is required, use strtomem_pad().
335 *
336 * Note that the size of @dest is not an argument, as the length of @dest
337 * must be discoverable by the compiler.
338 */
339#define strtomem(dest, src) do { \
340 const size_t _dest_len = __builtin_object_size(dest, 1); \
341 const size_t _src_len = __builtin_object_size(src, 1); \
342 \
343 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
344 _dest_len == (size_t)-1); \
345 memcpy(dest, src, strnlen(src, min(_src_len, _dest_len))); \
346} while (0)
347
348/**
349 * memset_after - Set a value after a struct member to the end of a struct
350 *
351 * @obj: Address of target struct instance
352 * @v: Byte value to repeatedly write
353 * @member: after which struct member to start writing bytes
354 *
355 * This is good for clearing padding following the given member.
356 */
357#define memset_after(obj, v, member) \
358({ \
359 u8 *__ptr = (u8 *)(obj); \
360 typeof(v) __val = (v); \
361 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \
362 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \
363})
364
365/**
366 * memset_startat - Set a value starting at a member to the end of a struct
367 *
368 * @obj: Address of target struct instance
369 * @v: Byte value to repeatedly write
370 * @member: struct member to start writing at
371 *
372 * Note that if there is padding between the prior member and the target
373 * member, memset_after() should be used to clear the prior padding.
374 */
375#define memset_startat(obj, v, member) \
376({ \
377 u8 *__ptr = (u8 *)(obj); \
378 typeof(v) __val = (v); \
379 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \
380 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \
381})
382
383/**
384 * str_has_prefix - Test if a string has a given prefix
385 * @str: The string to test
386 * @prefix: The string to see if @str starts with
387 *
388 * A common way to test a prefix of a string is to do:
389 * strncmp(str, prefix, sizeof(prefix) - 1)
390 *
391 * But this can lead to bugs due to typos, or if prefix is a pointer
392 * and not a constant. Instead use str_has_prefix().
393 *
394 * Returns:
395 * * strlen(@prefix) if @str starts with @prefix
396 * * 0 if @str does not start with @prefix
397 */
398static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
399{
400 size_t len = strlen(prefix);
401 return strncmp(str, prefix, len) == 0 ? len : 0;
402}
403
404#endif /* _LINUX_STRING_H_ */