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_STRLCPY
70size_t strlcpy(char *, const char *, size_t);
71#endif
72#ifndef __HAVE_ARCH_STRSCPY
73ssize_t strscpy(char *, const char *, size_t);
74#endif
75
76/* Wraps calls to strscpy()/memset(), no arch specific code required */
77ssize_t strscpy_pad(char *dest, const char *src, size_t count);
78
79#ifndef __HAVE_ARCH_STRCAT
80extern char * strcat(char *, const char *);
81#endif
82#ifndef __HAVE_ARCH_STRNCAT
83extern char * strncat(char *, const char *, __kernel_size_t);
84#endif
85#ifndef __HAVE_ARCH_STRLCAT
86extern size_t strlcat(char *, const char *, __kernel_size_t);
87#endif
88#ifndef __HAVE_ARCH_STRCMP
89extern int strcmp(const char *,const char *);
90#endif
91#ifndef __HAVE_ARCH_STRNCMP
92extern int strncmp(const char *,const char *,__kernel_size_t);
93#endif
94#ifndef __HAVE_ARCH_STRCASECMP
95extern int strcasecmp(const char *s1, const char *s2);
96#endif
97#ifndef __HAVE_ARCH_STRNCASECMP
98extern int strncasecmp(const char *s1, const char *s2, size_t n);
99#endif
100#ifndef __HAVE_ARCH_STRCHR
101extern char * strchr(const char *,int);
102#endif
103#ifndef __HAVE_ARCH_STRCHRNUL
104extern char * strchrnul(const char *,int);
105#endif
106extern char * strnchrnul(const char *, size_t, int);
107#ifndef __HAVE_ARCH_STRNCHR
108extern char * strnchr(const char *, size_t, int);
109#endif
110#ifndef __HAVE_ARCH_STRRCHR
111extern char * strrchr(const char *,int);
112#endif
113extern char * __must_check skip_spaces(const char *);
114
115extern char *strim(char *);
116
117static inline __must_check char *strstrip(char *str)
118{
119 return strim(str);
120}
121
122#ifndef __HAVE_ARCH_STRSTR
123extern char * strstr(const char *, const char *);
124#endif
125#ifndef __HAVE_ARCH_STRNSTR
126extern char * strnstr(const char *, const char *, size_t);
127#endif
128#ifndef __HAVE_ARCH_STRLEN
129extern __kernel_size_t strlen(const char *);
130#endif
131#ifndef __HAVE_ARCH_STRNLEN
132extern __kernel_size_t strnlen(const char *,__kernel_size_t);
133#endif
134#ifndef __HAVE_ARCH_STRPBRK
135extern char * strpbrk(const char *,const char *);
136#endif
137#ifndef __HAVE_ARCH_STRSEP
138extern char * strsep(char **,const char *);
139#endif
140#ifndef __HAVE_ARCH_STRSPN
141extern __kernel_size_t strspn(const char *,const char *);
142#endif
143#ifndef __HAVE_ARCH_STRCSPN
144extern __kernel_size_t strcspn(const char *,const char *);
145#endif
146
147#ifndef __HAVE_ARCH_MEMSET
148extern void * memset(void *,int,__kernel_size_t);
149#endif
150
151#ifndef __HAVE_ARCH_MEMSET16
152extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
153#endif
154
155#ifndef __HAVE_ARCH_MEMSET32
156extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
157#endif
158
159#ifndef __HAVE_ARCH_MEMSET64
160extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
161#endif
162
163static inline void *memset_l(unsigned long *p, unsigned long v,
164 __kernel_size_t n)
165{
166 if (BITS_PER_LONG == 32)
167 return memset32((uint32_t *)p, v, n);
168 else
169 return memset64((uint64_t *)p, v, n);
170}
171
172static inline void *memset_p(void **p, void *v, __kernel_size_t n)
173{
174 if (BITS_PER_LONG == 32)
175 return memset32((uint32_t *)p, (uintptr_t)v, n);
176 else
177 return memset64((uint64_t *)p, (uintptr_t)v, n);
178}
179
180extern void **__memcat_p(void **a, void **b);
181#define memcat_p(a, b) ({ \
182 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \
183 "type mismatch in memcat_p()"); \
184 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \
185})
186
187#ifndef __HAVE_ARCH_MEMCPY
188extern void * memcpy(void *,const void *,__kernel_size_t);
189#endif
190#ifndef __HAVE_ARCH_MEMMOVE
191extern void * memmove(void *,const void *,__kernel_size_t);
192#endif
193#ifndef __HAVE_ARCH_MEMSCAN
194extern void * memscan(void *,int,__kernel_size_t);
195#endif
196#ifndef __HAVE_ARCH_MEMCMP
197extern int memcmp(const void *,const void *,__kernel_size_t);
198#endif
199#ifndef __HAVE_ARCH_BCMP
200extern int bcmp(const void *,const void *,__kernel_size_t);
201#endif
202#ifndef __HAVE_ARCH_MEMCHR
203extern void * memchr(const void *,int,__kernel_size_t);
204#endif
205#ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
206static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
207{
208 memcpy(dst, src, cnt);
209}
210#endif
211
212void *memchr_inv(const void *s, int c, size_t n);
213char *strreplace(char *str, char old, char new);
214
215extern void kfree_const(const void *x);
216
217extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
218extern const char *kstrdup_const(const char *s, gfp_t gfp);
219extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
220extern void *kmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
221extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
222extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
223
224extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
225extern void argv_free(char **argv);
226
227extern bool sysfs_streq(const char *s1, const char *s2);
228int match_string(const char * const *array, size_t n, const char *string);
229int __sysfs_match_string(const char * const *array, size_t n, const char *s);
230
231/**
232 * sysfs_match_string - matches given string in an array
233 * @_a: array of strings
234 * @_s: string to match with
235 *
236 * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
237 */
238#define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
239
240#ifdef CONFIG_BINARY_PRINTF
241int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
242int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
243int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
244#endif
245
246extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
247 const void *from, size_t available);
248
249int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
250
251/**
252 * strstarts - does @str start with @prefix?
253 * @str: string to examine
254 * @prefix: prefix to look for.
255 */
256static inline bool strstarts(const char *str, const char *prefix)
257{
258 return strncmp(str, prefix, strlen(prefix)) == 0;
259}
260
261size_t memweight(const void *ptr, size_t bytes);
262
263/**
264 * memzero_explicit - Fill a region of memory (e.g. sensitive
265 * keying data) with 0s.
266 * @s: Pointer to the start of the area.
267 * @count: The size of the area.
268 *
269 * Note: usually using memset() is just fine (!), but in cases
270 * where clearing out _local_ data at the end of a scope is
271 * necessary, memzero_explicit() should be used instead in
272 * order to prevent the compiler from optimising away zeroing.
273 *
274 * memzero_explicit() doesn't need an arch-specific version as
275 * it just invokes the one of memset() implicitly.
276 */
277static inline void memzero_explicit(void *s, size_t count)
278{
279 memset(s, 0, count);
280 barrier_data(s);
281}
282
283/**
284 * kbasename - return the last part of a pathname.
285 *
286 * @path: path to extract the filename from.
287 */
288static inline const char *kbasename(const char *path)
289{
290 const char *tail = strrchr(path, '/');
291 return tail ? tail + 1 : path;
292}
293
294#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
295#include <linux/fortify-string.h>
296#endif
297#ifndef unsafe_memcpy
298#define unsafe_memcpy(dst, src, bytes, justification) \
299 memcpy(dst, src, bytes)
300#endif
301
302void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
303 int pad);
304
305/**
306 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer
307 *
308 * @dest: Pointer of destination character array (marked as __nonstring)
309 * @src: Pointer to NUL-terminated string
310 * @pad: Padding character to fill any remaining bytes of @dest after copy
311 *
312 * This is a replacement for strncpy() uses where the destination is not
313 * a NUL-terminated string, but with bounds checking on the source size, and
314 * an explicit padding character. If padding is not required, use strtomem().
315 *
316 * Note that the size of @dest is not an argument, as the length of @dest
317 * must be discoverable by the compiler.
318 */
319#define strtomem_pad(dest, src, pad) do { \
320 const size_t _dest_len = __builtin_object_size(dest, 1); \
321 const size_t _src_len = __builtin_object_size(src, 1); \
322 \
323 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
324 _dest_len == (size_t)-1); \
325 memcpy_and_pad(dest, _dest_len, src, \
326 strnlen(src, min(_src_len, _dest_len)), pad); \
327} while (0)
328
329/**
330 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer
331 *
332 * @dest: Pointer of destination character array (marked as __nonstring)
333 * @src: Pointer to NUL-terminated string
334 *
335 * This is a replacement for strncpy() uses where the destination is not
336 * a NUL-terminated string, but with bounds checking on the source size, and
337 * without trailing padding. If padding is required, use strtomem_pad().
338 *
339 * Note that the size of @dest is not an argument, as the length of @dest
340 * must be discoverable by the compiler.
341 */
342#define strtomem(dest, src) do { \
343 const size_t _dest_len = __builtin_object_size(dest, 1); \
344 const size_t _src_len = __builtin_object_size(src, 1); \
345 \
346 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
347 _dest_len == (size_t)-1); \
348 memcpy(dest, src, strnlen(src, min(_src_len, _dest_len))); \
349} while (0)
350
351/**
352 * memset_after - Set a value after a struct member to the end of a struct
353 *
354 * @obj: Address of target struct instance
355 * @v: Byte value to repeatedly write
356 * @member: after which struct member to start writing bytes
357 *
358 * This is good for clearing padding following the given member.
359 */
360#define memset_after(obj, v, member) \
361({ \
362 u8 *__ptr = (u8 *)(obj); \
363 typeof(v) __val = (v); \
364 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \
365 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \
366})
367
368/**
369 * memset_startat - Set a value starting at a member to the end of a struct
370 *
371 * @obj: Address of target struct instance
372 * @v: Byte value to repeatedly write
373 * @member: struct member to start writing at
374 *
375 * Note that if there is padding between the prior member and the target
376 * member, memset_after() should be used to clear the prior padding.
377 */
378#define memset_startat(obj, v, member) \
379({ \
380 u8 *__ptr = (u8 *)(obj); \
381 typeof(v) __val = (v); \
382 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \
383 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \
384})
385
386/**
387 * str_has_prefix - Test if a string has a given prefix
388 * @str: The string to test
389 * @prefix: The string to see if @str starts with
390 *
391 * A common way to test a prefix of a string is to do:
392 * strncmp(str, prefix, sizeof(prefix) - 1)
393 *
394 * But this can lead to bugs due to typos, or if prefix is a pointer
395 * and not a constant. Instead use str_has_prefix().
396 *
397 * Returns:
398 * * strlen(@prefix) if @str starts with @prefix
399 * * 0 if @str does not start with @prefix
400 */
401static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
402{
403 size_t len = strlen(prefix);
404 return strncmp(str, prefix, len) == 0 ? len : 0;
405}
406
407#endif /* _LINUX_STRING_H_ */