projects/linux·blob v6.12-rc2 · refs

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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_STRING_H_
3#define _LINUX_STRING_H_
4
5#include <linux/args.h>
6#include <linux/array_size.h>
7#include <linux/compiler.h> /* for inline */
8#include <linux/types.h> /* for size_t */
9#include <linux/stddef.h> /* for NULL */
10#include <linux/err.h> /* for ERR_PTR() */
11#include <linux/errno.h> /* for E2BIG */
12#include <linux/overflow.h> /* for check_mul_overflow() */
13#include <linux/stdarg.h>
14#include <uapi/linux/string.h>
15
16extern char *strndup_user(const char __user *, long);
17extern void *memdup_user(const void __user *, size_t) __realloc_size(2);
18extern void *vmemdup_user(const void __user *, size_t) __realloc_size(2);
19extern void *memdup_user_nul(const void __user *, size_t);
20
21/**
22 * memdup_array_user - duplicate array from user space
23 * @src: source address in user space
24 * @n: number of array members to copy
25 * @size: size of one array member
26 *
27 * Return: an ERR_PTR() on failure. Result is physically
28 * contiguous, to be freed by kfree().
29 */
30static inline __realloc_size(2, 3)
31void *memdup_array_user(const void __user *src, size_t n, size_t size)
32{
33 size_t nbytes;
34
35 if (check_mul_overflow(n, size, &nbytes))
36 return ERR_PTR(-EOVERFLOW);
37
38 return memdup_user(src, nbytes);
39}
40
41/**
42 * vmemdup_array_user - duplicate array from user space
43 * @src: source address in user space
44 * @n: number of array members to copy
45 * @size: size of one array member
46 *
47 * Return: an ERR_PTR() on failure. Result may be not
48 * physically contiguous. Use kvfree() to free.
49 */
50static inline __realloc_size(2, 3)
51void *vmemdup_array_user(const void __user *src, size_t n, size_t size)
52{
53 size_t nbytes;
54
55 if (check_mul_overflow(n, size, &nbytes))
56 return ERR_PTR(-EOVERFLOW);
57
58 return vmemdup_user(src, nbytes);
59}
60
61/*
62 * Include machine specific inline routines
63 */
64#include <asm/string.h>
65
66#ifndef __HAVE_ARCH_STRCPY
67extern char * strcpy(char *,const char *);
68#endif
69#ifndef __HAVE_ARCH_STRNCPY
70extern char * strncpy(char *,const char *, __kernel_size_t);
71#endif
72ssize_t sized_strscpy(char *, const char *, size_t);
73
74/*
75 * The 2 argument style can only be used when dst is an array with a
76 * known size.
77 */
78#define __strscpy0(dst, src, ...) \
79 sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst) + \
80 __must_be_cstr(dst) + __must_be_cstr(src))
81#define __strscpy1(dst, src, size) \
82 sized_strscpy(dst, src, size + __must_be_cstr(dst) + __must_be_cstr(src))
83
84#define __strscpy_pad0(dst, src, ...) \
85 sized_strscpy_pad(dst, src, sizeof(dst) + __must_be_array(dst) + \
86 __must_be_cstr(dst) + __must_be_cstr(src))
87#define __strscpy_pad1(dst, src, size) \
88 sized_strscpy_pad(dst, src, size + __must_be_cstr(dst) + __must_be_cstr(src))
89
90/**
91 * strscpy - Copy a C-string into a sized buffer
92 * @dst: Where to copy the string to
93 * @src: Where to copy the string from
94 * @...: Size of destination buffer (optional)
95 *
96 * Copy the source string @src, or as much of it as fits, into the
97 * destination @dst buffer. The behavior is undefined if the string
98 * buffers overlap. The destination @dst buffer is always NUL terminated,
99 * unless it's zero-sized.
100 *
101 * The size argument @... is only required when @dst is not an array, or
102 * when the copy needs to be smaller than sizeof(@dst).
103 *
104 * Preferred to strncpy() since it always returns a valid string, and
105 * doesn't unnecessarily force the tail of the destination buffer to be
106 * zero padded. If padding is desired please use strscpy_pad().
107 *
108 * Returns the number of characters copied in @dst (not including the
109 * trailing %NUL) or -E2BIG if @size is 0 or the copy from @src was
110 * truncated.
111 */
112#define strscpy(dst, src, ...) \
113 CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
114
115#define sized_strscpy_pad(dest, src, count) ({ \
116 char *__dst = (dest); \
117 const char *__src = (src); \
118 const size_t __count = (count); \
119 ssize_t __wrote; \
120 \
121 __wrote = sized_strscpy(__dst, __src, __count); \
122 if (__wrote >= 0 && __wrote < __count) \
123 memset(__dst + __wrote + 1, 0, __count - __wrote - 1); \
124 __wrote; \
125})
126
127/**
128 * strscpy_pad() - Copy a C-string into a sized buffer
129 * @dst: Where to copy the string to
130 * @src: Where to copy the string from
131 * @...: Size of destination buffer
132 *
133 * Copy the string, or as much of it as fits, into the dest buffer. The
134 * behavior is undefined if the string buffers overlap. The destination
135 * buffer is always %NUL terminated, unless it's zero-sized.
136 *
137 * If the source string is shorter than the destination buffer, the
138 * remaining bytes in the buffer will be filled with %NUL bytes.
139 *
140 * For full explanation of why you may want to consider using the
141 * 'strscpy' functions please see the function docstring for strscpy().
142 *
143 * Returns:
144 * * The number of characters copied (not including the trailing %NULs)
145 * * -E2BIG if count is 0 or @src was truncated.
146 */
147#define strscpy_pad(dst, src, ...) \
148 CONCATENATE(__strscpy_pad, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
149
150#ifndef __HAVE_ARCH_STRCAT
151extern char * strcat(char *, const char *);
152#endif
153#ifndef __HAVE_ARCH_STRNCAT
154extern char * strncat(char *, const char *, __kernel_size_t);
155#endif
156#ifndef __HAVE_ARCH_STRLCAT
157extern size_t strlcat(char *, const char *, __kernel_size_t);
158#endif
159#ifndef __HAVE_ARCH_STRCMP
160extern int strcmp(const char *,const char *);
161#endif
162#ifndef __HAVE_ARCH_STRNCMP
163extern int strncmp(const char *,const char *,__kernel_size_t);
164#endif
165#ifndef __HAVE_ARCH_STRCASECMP
166extern int strcasecmp(const char *s1, const char *s2);
167#endif
168#ifndef __HAVE_ARCH_STRNCASECMP
169extern int strncasecmp(const char *s1, const char *s2, size_t n);
170#endif
171#ifndef __HAVE_ARCH_STRCHR
172extern char * strchr(const char *,int);
173#endif
174#ifndef __HAVE_ARCH_STRCHRNUL
175extern char * strchrnul(const char *,int);
176#endif
177extern char * strnchrnul(const char *, size_t, int);
178#ifndef __HAVE_ARCH_STRNCHR
179extern char * strnchr(const char *, size_t, int);
180#endif
181#ifndef __HAVE_ARCH_STRRCHR
182extern char * strrchr(const char *,int);
183#endif
184extern char * __must_check skip_spaces(const char *);
185
186extern char *strim(char *);
187
188static inline __must_check char *strstrip(char *str)
189{
190 return strim(str);
191}
192
193#ifndef __HAVE_ARCH_STRSTR
194extern char * strstr(const char *, const char *);
195#endif
196#ifndef __HAVE_ARCH_STRNSTR
197extern char * strnstr(const char *, const char *, size_t);
198#endif
199#ifndef __HAVE_ARCH_STRLEN
200extern __kernel_size_t strlen(const char *);
201#endif
202#ifndef __HAVE_ARCH_STRNLEN
203extern __kernel_size_t strnlen(const char *,__kernel_size_t);
204#endif
205#ifndef __HAVE_ARCH_STRPBRK
206extern char * strpbrk(const char *,const char *);
207#endif
208#ifndef __HAVE_ARCH_STRSEP
209extern char * strsep(char **,const char *);
210#endif
211#ifndef __HAVE_ARCH_STRSPN
212extern __kernel_size_t strspn(const char *,const char *);
213#endif
214#ifndef __HAVE_ARCH_STRCSPN
215extern __kernel_size_t strcspn(const char *,const char *);
216#endif
217
218#ifndef __HAVE_ARCH_MEMSET
219extern void * memset(void *,int,__kernel_size_t);
220#endif
221
222#ifndef __HAVE_ARCH_MEMSET16
223extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
224#endif
225
226#ifndef __HAVE_ARCH_MEMSET32
227extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
228#endif
229
230#ifndef __HAVE_ARCH_MEMSET64
231extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
232#endif
233
234static inline void *memset_l(unsigned long *p, unsigned long v,
235 __kernel_size_t n)
236{
237 if (BITS_PER_LONG == 32)
238 return memset32((uint32_t *)p, v, n);
239 else
240 return memset64((uint64_t *)p, v, n);
241}
242
243static inline void *memset_p(void **p, void *v, __kernel_size_t n)
244{
245 if (BITS_PER_LONG == 32)
246 return memset32((uint32_t *)p, (uintptr_t)v, n);
247 else
248 return memset64((uint64_t *)p, (uintptr_t)v, n);
249}
250
251extern void **__memcat_p(void **a, void **b);
252#define memcat_p(a, b) ({ \
253 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \
254 "type mismatch in memcat_p()"); \
255 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \
256})
257
258#ifndef __HAVE_ARCH_MEMCPY
259extern void * memcpy(void *,const void *,__kernel_size_t);
260#endif
261#ifndef __HAVE_ARCH_MEMMOVE
262extern void * memmove(void *,const void *,__kernel_size_t);
263#endif
264#ifndef __HAVE_ARCH_MEMSCAN
265extern void * memscan(void *,int,__kernel_size_t);
266#endif
267#ifndef __HAVE_ARCH_MEMCMP
268extern int memcmp(const void *,const void *,__kernel_size_t);
269#endif
270#ifndef __HAVE_ARCH_BCMP
271extern int bcmp(const void *,const void *,__kernel_size_t);
272#endif
273#ifndef __HAVE_ARCH_MEMCHR
274extern void * memchr(const void *,int,__kernel_size_t);
275#endif
276#ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
277static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
278{
279 memcpy(dst, src, cnt);
280}
281#endif
282
283void *memchr_inv(const void *s, int c, size_t n);
284char *strreplace(char *str, char old, char new);
285
286/**
287 * mem_is_zero - Check if an area of memory is all 0's.
288 * @s: The memory area
289 * @n: The size of the area
290 *
291 * Return: True if the area of memory is all 0's.
292 */
293static inline bool mem_is_zero(const void *s, size_t n)
294{
295 return !memchr_inv(s, 0, n);
296}
297
298extern void kfree_const(const void *x);
299
300extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
301extern const char *kstrdup_const(const char *s, gfp_t gfp);
302extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
303extern void *kmemdup_noprof(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
304#define kmemdup(...) alloc_hooks(kmemdup_noprof(__VA_ARGS__))
305
306extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
307extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
308extern void *kmemdup_array(const void *src, size_t count, size_t element_size, gfp_t gfp)
309 __realloc_size(2, 3);
310
311/* lib/argv_split.c */
312extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
313extern void argv_free(char **argv);
314
315/* lib/cmdline.c */
316extern int get_option(char **str, int *pint);
317extern char *get_options(const char *str, int nints, int *ints);
318extern unsigned long long memparse(const char *ptr, char **retptr);
319extern bool parse_option_str(const char *str, const char *option);
320extern char *next_arg(char *args, char **param, char **val);
321
322extern bool sysfs_streq(const char *s1, const char *s2);
323int match_string(const char * const *array, size_t n, const char *string);
324int __sysfs_match_string(const char * const *array, size_t n, const char *s);
325
326/**
327 * sysfs_match_string - matches given string in an array
328 * @_a: array of strings
329 * @_s: string to match with
330 *
331 * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
332 */
333#define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
334
335#ifdef CONFIG_BINARY_PRINTF
336int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
337int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
338int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
339#endif
340
341extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
342 const void *from, size_t available);
343
344int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
345
346/**
347 * strstarts - does @str start with @prefix?
348 * @str: string to examine
349 * @prefix: prefix to look for.
350 */
351static inline bool strstarts(const char *str, const char *prefix)
352{
353 return strncmp(str, prefix, strlen(prefix)) == 0;
354}
355
356size_t memweight(const void *ptr, size_t bytes);
357
358/**
359 * memzero_explicit - Fill a region of memory (e.g. sensitive
360 * keying data) with 0s.
361 * @s: Pointer to the start of the area.
362 * @count: The size of the area.
363 *
364 * Note: usually using memset() is just fine (!), but in cases
365 * where clearing out _local_ data at the end of a scope is
366 * necessary, memzero_explicit() should be used instead in
367 * order to prevent the compiler from optimising away zeroing.
368 *
369 * memzero_explicit() doesn't need an arch-specific version as
370 * it just invokes the one of memset() implicitly.
371 */
372static inline void memzero_explicit(void *s, size_t count)
373{
374 memset(s, 0, count);
375 barrier_data(s);
376}
377
378/**
379 * kbasename - return the last part of a pathname.
380 *
381 * @path: path to extract the filename from.
382 */
383static inline const char *kbasename(const char *path)
384{
385 const char *tail = strrchr(path, '/');
386 return tail ? tail + 1 : path;
387}
388
389#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
390#include <linux/fortify-string.h>
391#endif
392#ifndef unsafe_memcpy
393#define unsafe_memcpy(dst, src, bytes, justification) \
394 memcpy(dst, src, bytes)
395#endif
396
397void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
398 int pad);
399
400/**
401 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer
402 *
403 * @dest: Pointer of destination character array (marked as __nonstring)
404 * @src: Pointer to NUL-terminated string
405 * @pad: Padding character to fill any remaining bytes of @dest after copy
406 *
407 * This is a replacement for strncpy() uses where the destination is not
408 * a NUL-terminated string, but with bounds checking on the source size, and
409 * an explicit padding character. If padding is not required, use strtomem().
410 *
411 * Note that the size of @dest is not an argument, as the length of @dest
412 * must be discoverable by the compiler.
413 */
414#define strtomem_pad(dest, src, pad) do { \
415 const size_t _dest_len = __builtin_object_size(dest, 1); \
416 const size_t _src_len = __builtin_object_size(src, 1); \
417 \
418 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
419 _dest_len == (size_t)-1); \
420 memcpy_and_pad(dest, _dest_len, src, \
421 strnlen(src, min(_src_len, _dest_len)), pad); \
422} while (0)
423
424/**
425 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer
426 *
427 * @dest: Pointer of destination character array (marked as __nonstring)
428 * @src: Pointer to NUL-terminated string
429 *
430 * This is a replacement for strncpy() uses where the destination is not
431 * a NUL-terminated string, but with bounds checking on the source size, and
432 * without trailing padding. If padding is required, use strtomem_pad().
433 *
434 * Note that the size of @dest is not an argument, as the length of @dest
435 * must be discoverable by the compiler.
436 */
437#define strtomem(dest, src) do { \
438 const size_t _dest_len = __builtin_object_size(dest, 1); \
439 const size_t _src_len = __builtin_object_size(src, 1); \
440 \
441 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
442 _dest_len == (size_t)-1); \
443 memcpy(dest, src, strnlen(src, min(_src_len, _dest_len))); \
444} while (0)
445
446/**
447 * memtostr - Copy a possibly non-NUL-term string to a NUL-term string
448 * @dest: Pointer to destination NUL-terminates string
449 * @src: Pointer to character array (likely marked as __nonstring)
450 *
451 * This is a replacement for strncpy() uses where the source is not
452 * a NUL-terminated string.
453 *
454 * Note that sizes of @dest and @src must be known at compile-time.
455 */
456#define memtostr(dest, src) do { \
457 const size_t _dest_len = __builtin_object_size(dest, 1); \
458 const size_t _src_len = __builtin_object_size(src, 1); \
459 const size_t _src_chars = strnlen(src, _src_len); \
460 const size_t _copy_len = min(_dest_len - 1, _src_chars); \
461 \
462 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
463 !__builtin_constant_p(_src_len) || \
464 _dest_len == 0 || _dest_len == (size_t)-1 || \
465 _src_len == 0 || _src_len == (size_t)-1); \
466 memcpy(dest, src, _copy_len); \
467 dest[_copy_len] = '\0'; \
468} while (0)
469
470/**
471 * memtostr_pad - Copy a possibly non-NUL-term string to a NUL-term string
472 * with NUL padding in the destination
473 * @dest: Pointer to destination NUL-terminates string
474 * @src: Pointer to character array (likely marked as __nonstring)
475 *
476 * This is a replacement for strncpy() uses where the source is not
477 * a NUL-terminated string.
478 *
479 * Note that sizes of @dest and @src must be known at compile-time.
480 */
481#define memtostr_pad(dest, src) do { \
482 const size_t _dest_len = __builtin_object_size(dest, 1); \
483 const size_t _src_len = __builtin_object_size(src, 1); \
484 const size_t _src_chars = strnlen(src, _src_len); \
485 const size_t _copy_len = min(_dest_len - 1, _src_chars); \
486 \
487 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
488 !__builtin_constant_p(_src_len) || \
489 _dest_len == 0 || _dest_len == (size_t)-1 || \
490 _src_len == 0 || _src_len == (size_t)-1); \
491 memcpy(dest, src, _copy_len); \
492 memset(&dest[_copy_len], 0, _dest_len - _copy_len); \
493} while (0)
494
495/**
496 * memset_after - Set a value after a struct member to the end of a struct
497 *
498 * @obj: Address of target struct instance
499 * @v: Byte value to repeatedly write
500 * @member: after which struct member to start writing bytes
501 *
502 * This is good for clearing padding following the given member.
503 */
504#define memset_after(obj, v, member) \
505({ \
506 u8 *__ptr = (u8 *)(obj); \
507 typeof(v) __val = (v); \
508 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \
509 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \
510})
511
512/**
513 * memset_startat - Set a value starting at a member to the end of a struct
514 *
515 * @obj: Address of target struct instance
516 * @v: Byte value to repeatedly write
517 * @member: struct member to start writing at
518 *
519 * Note that if there is padding between the prior member and the target
520 * member, memset_after() should be used to clear the prior padding.
521 */
522#define memset_startat(obj, v, member) \
523({ \
524 u8 *__ptr = (u8 *)(obj); \
525 typeof(v) __val = (v); \
526 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \
527 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \
528})
529
530/**
531 * str_has_prefix - Test if a string has a given prefix
532 * @str: The string to test
533 * @prefix: The string to see if @str starts with
534 *
535 * A common way to test a prefix of a string is to do:
536 * strncmp(str, prefix, sizeof(prefix) - 1)
537 *
538 * But this can lead to bugs due to typos, or if prefix is a pointer
539 * and not a constant. Instead use str_has_prefix().
540 *
541 * Returns:
542 * * strlen(@prefix) if @str starts with @prefix
543 * * 0 if @str does not start with @prefix
544 */
545static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
546{
547 size_t len = strlen(prefix);
548 return strncmp(str, prefix, len) == 0 ? len : 0;
549}
550
551#endif /* _LINUX_STRING_H_ */