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