Linux kernel mirror (for testing)
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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/args.h>
6#include <linux/array_size.h>
7#include <linux/cleanup.h> /* for DEFINE_FREE() */
8#include <linux/compiler.h> /* for inline */
9#include <linux/types.h> /* for size_t */
10#include <linux/stddef.h> /* for NULL */
11#include <linux/err.h> /* for ERR_PTR() */
12#include <linux/errno.h> /* for E2BIG */
13#include <linux/overflow.h> /* for check_mul_overflow() */
14#include <linux/stdarg.h>
15#include <uapi/linux/string.h>
16
17extern char *strndup_user(const char __user *, long);
18extern void *memdup_user(const void __user *, size_t) __realloc_size(2);
19extern void *vmemdup_user(const void __user *, size_t) __realloc_size(2);
20extern void *memdup_user_nul(const void __user *, size_t);
21
22/**
23 * memdup_array_user - duplicate array from user space
24 * @src: source address in user space
25 * @n: number of array members to copy
26 * @size: size of one array member
27 *
28 * Return: an ERR_PTR() on failure. Result is physically
29 * contiguous, to be freed by kfree().
30 */
31static inline __realloc_size(2, 3)
32void *memdup_array_user(const void __user *src, size_t n, size_t size)
33{
34 size_t nbytes;
35
36 if (check_mul_overflow(n, size, &nbytes))
37 return ERR_PTR(-EOVERFLOW);
38
39 return memdup_user(src, nbytes);
40}
41
42/**
43 * vmemdup_array_user - duplicate array from user space
44 * @src: source address in user space
45 * @n: number of array members to copy
46 * @size: size of one array member
47 *
48 * Return: an ERR_PTR() on failure. Result may be not
49 * physically contiguous. Use kvfree() to free.
50 */
51static inline __realloc_size(2, 3)
52void *vmemdup_array_user(const void __user *src, size_t n, size_t size)
53{
54 size_t nbytes;
55
56 if (check_mul_overflow(n, size, &nbytes))
57 return ERR_PTR(-EOVERFLOW);
58
59 return vmemdup_user(src, nbytes);
60}
61
62/*
63 * Include machine specific inline routines
64 */
65#include <asm/string.h>
66
67#ifndef __HAVE_ARCH_STRCPY
68extern char * strcpy(char *,const char *);
69#endif
70#ifndef __HAVE_ARCH_STRNCPY
71extern char * strncpy(char *,const char *, __kernel_size_t);
72#endif
73ssize_t sized_strscpy(char *, const char *, size_t);
74
75/*
76 * The 2 argument style can only be used when dst is an array with a
77 * known size.
78 */
79#define __strscpy0(dst, src, ...) \
80 sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst) + \
81 __must_be_cstr(dst) + __must_be_cstr(src))
82#define __strscpy1(dst, src, size) \
83 sized_strscpy(dst, src, size + __must_be_cstr(dst) + __must_be_cstr(src))
84
85#define __strscpy_pad0(dst, src, ...) \
86 sized_strscpy_pad(dst, src, sizeof(dst) + __must_be_array(dst) + \
87 __must_be_cstr(dst) + __must_be_cstr(src))
88#define __strscpy_pad1(dst, src, size) \
89 sized_strscpy_pad(dst, src, size + __must_be_cstr(dst) + __must_be_cstr(src))
90
91/**
92 * strscpy - Copy a C-string into a sized buffer
93 * @dst: Where to copy the string to
94 * @src: Where to copy the string from
95 * @...: Size of destination buffer (optional)
96 *
97 * Copy the source string @src, or as much of it as fits, into the
98 * destination @dst buffer. The behavior is undefined if the string
99 * buffers overlap. The destination @dst buffer is always NUL terminated,
100 * unless it's zero-sized.
101 *
102 * The size argument @... is only required when @dst is not an array, or
103 * when the copy needs to be smaller than sizeof(@dst).
104 *
105 * Preferred to strncpy() since it always returns a valid string, and
106 * doesn't unnecessarily force the tail of the destination buffer to be
107 * zero padded. If padding is desired please use strscpy_pad().
108 *
109 * Returns the number of characters copied in @dst (not including the
110 * trailing %NUL) or -E2BIG if @size is 0 or the copy from @src was
111 * truncated.
112 */
113#define strscpy(dst, src, ...) \
114 CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
115
116#define sized_strscpy_pad(dest, src, count) ({ \
117 char *__dst = (dest); \
118 const char *__src = (src); \
119 const size_t __count = (count); \
120 ssize_t __wrote; \
121 \
122 __wrote = sized_strscpy(__dst, __src, __count); \
123 if (__wrote >= 0 && __wrote < __count) \
124 memset(__dst + __wrote + 1, 0, __count - __wrote - 1); \
125 __wrote; \
126})
127
128/**
129 * strscpy_pad() - Copy a C-string into a sized buffer
130 * @dst: Where to copy the string to
131 * @src: Where to copy the string from
132 * @...: Size of destination buffer
133 *
134 * Copy the string, or as much of it as fits, into the dest buffer. The
135 * behavior is undefined if the string buffers overlap. The destination
136 * buffer is always %NUL terminated, unless it's zero-sized.
137 *
138 * If the source string is shorter than the destination buffer, the
139 * remaining bytes in the buffer will be filled with %NUL bytes.
140 *
141 * For full explanation of why you may want to consider using the
142 * 'strscpy' functions please see the function docstring for strscpy().
143 *
144 * Returns:
145 * * The number of characters copied (not including the trailing %NULs)
146 * * -E2BIG if count is 0 or @src was truncated.
147 */
148#define strscpy_pad(dst, src, ...) \
149 CONCATENATE(__strscpy_pad, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
150
151#ifndef __HAVE_ARCH_STRCAT
152extern char * strcat(char *, const char *);
153#endif
154#ifndef __HAVE_ARCH_STRNCAT
155extern char * strncat(char *, const char *, __kernel_size_t);
156#endif
157#ifndef __HAVE_ARCH_STRLCAT
158extern size_t strlcat(char *, const char *, __kernel_size_t);
159#endif
160#ifndef __HAVE_ARCH_STRCMP
161extern int strcmp(const char *,const char *);
162#endif
163#ifndef __HAVE_ARCH_STRNCMP
164extern int strncmp(const char *,const char *,__kernel_size_t);
165#endif
166#ifndef __HAVE_ARCH_STRCASECMP
167extern int strcasecmp(const char *s1, const char *s2);
168#endif
169#ifndef __HAVE_ARCH_STRNCASECMP
170extern int strncasecmp(const char *s1, const char *s2, size_t n);
171#endif
172#ifndef __HAVE_ARCH_STRCHR
173extern char * strchr(const char *,int);
174#endif
175#ifndef __HAVE_ARCH_STRCHRNUL
176extern char * strchrnul(const char *,int);
177#endif
178extern char * strnchrnul(const char *, size_t, int);
179#ifndef __HAVE_ARCH_STRNCHR
180extern char * strnchr(const char *, size_t, int);
181#endif
182#ifndef __HAVE_ARCH_STRRCHR
183extern char * strrchr(const char *,int);
184#endif
185extern char * __must_check skip_spaces(const char *);
186
187extern char *strim(char *);
188
189static inline __must_check char *strstrip(char *str)
190{
191 return strim(str);
192}
193
194#ifndef __HAVE_ARCH_STRSTR
195extern char * strstr(const char *, const char *);
196#endif
197#ifndef __HAVE_ARCH_STRNSTR
198extern char * strnstr(const char *, const char *, size_t);
199#endif
200#ifndef __HAVE_ARCH_STRLEN
201extern __kernel_size_t strlen(const char *);
202#endif
203#ifndef __HAVE_ARCH_STRNLEN
204extern __kernel_size_t strnlen(const char *,__kernel_size_t);
205#endif
206#ifndef __HAVE_ARCH_STRPBRK
207extern char * strpbrk(const char *,const char *);
208#endif
209#ifndef __HAVE_ARCH_STRSEP
210extern char * strsep(char **,const char *);
211#endif
212#ifndef __HAVE_ARCH_STRSPN
213extern __kernel_size_t strspn(const char *,const char *);
214#endif
215#ifndef __HAVE_ARCH_STRCSPN
216extern __kernel_size_t strcspn(const char *,const char *);
217#endif
218
219#ifndef __HAVE_ARCH_MEMSET
220extern void * memset(void *,int,__kernel_size_t);
221#endif
222
223#ifndef __HAVE_ARCH_MEMSET16
224extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
225#endif
226
227#ifndef __HAVE_ARCH_MEMSET32
228extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
229#endif
230
231#ifndef __HAVE_ARCH_MEMSET64
232extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
233#endif
234
235static inline void *memset_l(unsigned long *p, unsigned long v,
236 __kernel_size_t n)
237{
238 if (BITS_PER_LONG == 32)
239 return memset32((uint32_t *)p, v, n);
240 else
241 return memset64((uint64_t *)p, v, n);
242}
243
244static inline void *memset_p(void **p, void *v, __kernel_size_t n)
245{
246 if (BITS_PER_LONG == 32)
247 return memset32((uint32_t *)p, (uintptr_t)v, n);
248 else
249 return memset64((uint64_t *)p, (uintptr_t)v, n);
250}
251
252extern void **__memcat_p(void **a, void **b);
253#define memcat_p(a, b) ({ \
254 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \
255 "type mismatch in memcat_p()"); \
256 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \
257})
258
259#ifndef __HAVE_ARCH_MEMCPY
260extern void * memcpy(void *,const void *,__kernel_size_t);
261#endif
262#ifndef __HAVE_ARCH_MEMMOVE
263extern void * memmove(void *,const void *,__kernel_size_t);
264#endif
265#ifndef __HAVE_ARCH_MEMSCAN
266extern void * memscan(void *,int,__kernel_size_t);
267#endif
268#ifndef __HAVE_ARCH_MEMCMP
269extern int memcmp(const void *,const void *,__kernel_size_t);
270#endif
271#ifndef __HAVE_ARCH_BCMP
272extern int bcmp(const void *,const void *,__kernel_size_t);
273#endif
274#ifndef __HAVE_ARCH_MEMCHR
275extern void * memchr(const void *,int,__kernel_size_t);
276#endif
277#ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
278static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
279{
280 memcpy(dst, src, cnt);
281}
282#endif
283
284void *memchr_inv(const void *s, int c, size_t n);
285char *strreplace(char *str, char old, char new);
286
287/**
288 * mem_is_zero - Check if an area of memory is all 0's.
289 * @s: The memory area
290 * @n: The size of the area
291 *
292 * Return: True if the area of memory is all 0's.
293 */
294static inline bool mem_is_zero(const void *s, size_t n)
295{
296 return !memchr_inv(s, 0, n);
297}
298
299extern void kfree_const(const void *x);
300
301extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
302extern const char *kstrdup_const(const char *s, gfp_t gfp);
303extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
304extern void *kmemdup_noprof(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
305#define kmemdup(...) alloc_hooks(kmemdup_noprof(__VA_ARGS__))
306
307extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
308extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
309extern void *kmemdup_array(const void *src, size_t count, size_t element_size, gfp_t gfp)
310 __realloc_size(2, 3);
311
312/* lib/argv_split.c */
313extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
314extern void argv_free(char **argv);
315
316DEFINE_FREE(argv_free, char **, if (!IS_ERR_OR_NULL(_T)) argv_free(_T))
317
318/* lib/cmdline.c */
319extern int get_option(char **str, int *pint);
320extern char *get_options(const char *str, int nints, int *ints);
321extern unsigned long long memparse(const char *ptr, char **retptr);
322extern bool parse_option_str(const char *str, const char *option);
323extern char *next_arg(char *args, char **param, char **val);
324
325extern bool sysfs_streq(const char *s1, const char *s2);
326int match_string(const char * const *array, size_t n, const char *string);
327int __sysfs_match_string(const char * const *array, size_t n, const char *s);
328
329/**
330 * sysfs_match_string - matches given string in an array
331 * @_a: array of strings
332 * @_s: string to match with
333 *
334 * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
335 */
336#define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
337
338#ifdef CONFIG_BINARY_PRINTF
339__printf(3, 0) int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
340__printf(3, 0) int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
341#endif
342
343extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
344 const void *from, size_t available);
345
346int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
347
348/**
349 * strstarts - does @str start with @prefix?
350 * @str: string to examine
351 * @prefix: prefix to look for.
352 */
353static inline bool strstarts(const char *str, const char *prefix)
354{
355 return strncmp(str, prefix, strlen(prefix)) == 0;
356}
357
358size_t memweight(const void *ptr, size_t bytes);
359
360/**
361 * memzero_explicit - Fill a region of memory (e.g. sensitive
362 * keying data) with 0s.
363 * @s: Pointer to the start of the area.
364 * @count: The size of the area.
365 *
366 * Note: usually using memset() is just fine (!), but in cases
367 * where clearing out _local_ data at the end of a scope is
368 * necessary, memzero_explicit() should be used instead in
369 * order to prevent the compiler from optimising away zeroing.
370 *
371 * memzero_explicit() doesn't need an arch-specific version as
372 * it just invokes the one of memset() implicitly.
373 */
374static inline void memzero_explicit(void *s, size_t count)
375{
376 memset(s, 0, count);
377 barrier_data(s);
378}
379
380/**
381 * kbasename - return the last part of a pathname.
382 *
383 * @path: path to extract the filename from.
384 */
385static inline const char *kbasename(const char *path)
386{
387 const char *tail = strrchr(path, '/');
388 return tail ? tail + 1 : path;
389}
390
391#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
392#include <linux/fortify-string.h>
393#endif
394#ifndef unsafe_memcpy
395#define unsafe_memcpy(dst, src, bytes, justification) \
396 memcpy(dst, src, bytes)
397#endif
398
399void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
400 int pad);
401
402/**
403 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer
404 *
405 * @dest: Pointer of destination character array (marked as __nonstring)
406 * @src: Pointer to NUL-terminated string
407 * @pad: Padding character to fill any remaining bytes of @dest after copy
408 *
409 * This is a replacement for strncpy() uses where the destination is not
410 * a NUL-terminated string, but with bounds checking on the source size, and
411 * an explicit padding character. If padding is not required, use strtomem().
412 *
413 * Note that the size of @dest is not an argument, as the length of @dest
414 * must be discoverable by the compiler.
415 */
416#define strtomem_pad(dest, src, pad) do { \
417 const size_t _dest_len = __must_be_byte_array(dest) + \
418 __must_be_noncstr(dest) + \
419 ARRAY_SIZE(dest); \
420 const size_t _src_len = __must_be_cstr(src) + \
421 __builtin_object_size(src, 1); \
422 \
423 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
424 _dest_len == (size_t)-1); \
425 memcpy_and_pad(dest, _dest_len, src, \
426 strnlen(src, min(_src_len, _dest_len)), pad); \
427} while (0)
428
429/**
430 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer
431 *
432 * @dest: Pointer of destination character array (marked as __nonstring)
433 * @src: Pointer to NUL-terminated string
434 *
435 * This is a replacement for strncpy() uses where the destination is not
436 * a NUL-terminated string, but with bounds checking on the source size, and
437 * without trailing padding. If padding is required, use strtomem_pad().
438 *
439 * Note that the size of @dest is not an argument, as the length of @dest
440 * must be discoverable by the compiler.
441 */
442#define strtomem(dest, src) do { \
443 const size_t _dest_len = __must_be_byte_array(dest) + \
444 __must_be_noncstr(dest) + \
445 ARRAY_SIZE(dest); \
446 const size_t _src_len = __must_be_cstr(src) + \
447 __builtin_object_size(src, 1); \
448 \
449 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
450 _dest_len == (size_t)-1); \
451 memcpy(dest, src, strnlen(src, min(_src_len, _dest_len))); \
452} while (0)
453
454/**
455 * memtostr - Copy a possibly non-NUL-term string to a NUL-term string
456 * @dest: Pointer to destination NUL-terminates string
457 * @src: Pointer to character array (likely marked as __nonstring)
458 *
459 * This is a replacement for strncpy() uses where the source is not
460 * a NUL-terminated string.
461 *
462 * Note that sizes of @dest and @src must be known at compile-time.
463 */
464#define memtostr(dest, src) do { \
465 const size_t _dest_len = __must_be_byte_array(dest) + \
466 __must_be_cstr(dest) + \
467 ARRAY_SIZE(dest); \
468 const size_t _src_len = __must_be_noncstr(src) + \
469 __builtin_object_size(src, 1); \
470 const size_t _src_chars = strnlen(src, _src_len); \
471 const size_t _copy_len = min(_dest_len - 1, _src_chars); \
472 \
473 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
474 !__builtin_constant_p(_src_len) || \
475 _dest_len == 0 || _dest_len == (size_t)-1 || \
476 _src_len == 0 || _src_len == (size_t)-1); \
477 memcpy(dest, src, _copy_len); \
478 dest[_copy_len] = '\0'; \
479} while (0)
480
481/**
482 * memtostr_pad - Copy a possibly non-NUL-term string to a NUL-term string
483 * with NUL padding in the destination
484 * @dest: Pointer to destination NUL-terminates string
485 * @src: Pointer to character array (likely marked as __nonstring)
486 *
487 * This is a replacement for strncpy() uses where the source is not
488 * a NUL-terminated string.
489 *
490 * Note that sizes of @dest and @src must be known at compile-time.
491 */
492#define memtostr_pad(dest, src) do { \
493 const size_t _dest_len = __must_be_byte_array(dest) + \
494 __must_be_cstr(dest) + \
495 ARRAY_SIZE(dest); \
496 const size_t _src_len = __must_be_noncstr(src) + \
497 __builtin_object_size(src, 1); \
498 const size_t _src_chars = strnlen(src, _src_len); \
499 const size_t _copy_len = min(_dest_len - 1, _src_chars); \
500 \
501 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
502 !__builtin_constant_p(_src_len) || \
503 _dest_len == 0 || _dest_len == (size_t)-1 || \
504 _src_len == 0 || _src_len == (size_t)-1); \
505 memcpy(dest, src, _copy_len); \
506 memset(&dest[_copy_len], 0, _dest_len - _copy_len); \
507} while (0)
508
509/**
510 * memset_after - Set a value after a struct member to the end of a struct
511 *
512 * @obj: Address of target struct instance
513 * @v: Byte value to repeatedly write
514 * @member: after which struct member to start writing bytes
515 *
516 * This is good for clearing padding following the given member.
517 */
518#define memset_after(obj, v, member) \
519({ \
520 u8 *__ptr = (u8 *)(obj); \
521 typeof(v) __val = (v); \
522 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \
523 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \
524})
525
526/**
527 * memset_startat - Set a value starting at a member to the end of a struct
528 *
529 * @obj: Address of target struct instance
530 * @v: Byte value to repeatedly write
531 * @member: struct member to start writing at
532 *
533 * Note that if there is padding between the prior member and the target
534 * member, memset_after() should be used to clear the prior padding.
535 */
536#define memset_startat(obj, v, member) \
537({ \
538 u8 *__ptr = (u8 *)(obj); \
539 typeof(v) __val = (v); \
540 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \
541 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \
542})
543
544/**
545 * str_has_prefix - Test if a string has a given prefix
546 * @str: The string to test
547 * @prefix: The string to see if @str starts with
548 *
549 * A common way to test a prefix of a string is to do:
550 * strncmp(str, prefix, sizeof(prefix) - 1)
551 *
552 * But this can lead to bugs due to typos, or if prefix is a pointer
553 * and not a constant. Instead use str_has_prefix().
554 *
555 * Returns:
556 * * strlen(@prefix) if @str starts with @prefix
557 * * 0 if @str does not start with @prefix
558 */
559static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
560{
561 size_t len = strlen(prefix);
562 return strncmp(str, prefix, len) == 0 ? len : 0;
563}
564
565#endif /* _LINUX_STRING_H_ */