Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_STRING_H_
3#define _LINUX_STRING_H_
4
5
6#include <linux/compiler.h> /* for inline */
7#include <linux/types.h> /* for size_t */
8#include <linux/stddef.h> /* for NULL */
9#include <stdarg.h>
10#include <uapi/linux/string.h>
11
12extern char *strndup_user(const char __user *, long);
13extern void *memdup_user(const void __user *, size_t);
14extern void *vmemdup_user(const void __user *, size_t);
15extern void *memdup_user_nul(const void __user *, size_t);
16
17/*
18 * Include machine specific inline routines
19 */
20#include <asm/string.h>
21
22#ifndef __HAVE_ARCH_STRCPY
23extern char * strcpy(char *,const char *);
24#endif
25#ifndef __HAVE_ARCH_STRNCPY
26extern char * strncpy(char *,const char *, __kernel_size_t);
27#endif
28#ifndef __HAVE_ARCH_STRLCPY
29size_t strlcpy(char *, const char *, size_t);
30#endif
31#ifndef __HAVE_ARCH_STRSCPY
32ssize_t strscpy(char *, const char *, size_t);
33#endif
34
35/* Wraps calls to strscpy()/memset(), no arch specific code required */
36ssize_t strscpy_pad(char *dest, const char *src, size_t count);
37
38#ifndef __HAVE_ARCH_STRCAT
39extern char * strcat(char *, const char *);
40#endif
41#ifndef __HAVE_ARCH_STRNCAT
42extern char * strncat(char *, const char *, __kernel_size_t);
43#endif
44#ifndef __HAVE_ARCH_STRLCAT
45extern size_t strlcat(char *, const char *, __kernel_size_t);
46#endif
47#ifndef __HAVE_ARCH_STRCMP
48extern int strcmp(const char *,const char *);
49#endif
50#ifndef __HAVE_ARCH_STRNCMP
51extern int strncmp(const char *,const char *,__kernel_size_t);
52#endif
53#ifndef __HAVE_ARCH_STRCASECMP
54extern int strcasecmp(const char *s1, const char *s2);
55#endif
56#ifndef __HAVE_ARCH_STRNCASECMP
57extern int strncasecmp(const char *s1, const char *s2, size_t n);
58#endif
59#ifndef __HAVE_ARCH_STRCHR
60extern char * strchr(const char *,int);
61#endif
62#ifndef __HAVE_ARCH_STRCHRNUL
63extern char * strchrnul(const char *,int);
64#endif
65extern char * strnchrnul(const char *, size_t, int);
66#ifndef __HAVE_ARCH_STRNCHR
67extern char * strnchr(const char *, size_t, int);
68#endif
69#ifndef __HAVE_ARCH_STRRCHR
70extern char * strrchr(const char *,int);
71#endif
72extern char * __must_check skip_spaces(const char *);
73
74extern char *strim(char *);
75
76static inline __must_check char *strstrip(char *str)
77{
78 return strim(str);
79}
80
81#ifndef __HAVE_ARCH_STRSTR
82extern char * strstr(const char *, const char *);
83#endif
84#ifndef __HAVE_ARCH_STRNSTR
85extern char * strnstr(const char *, const char *, size_t);
86#endif
87#ifndef __HAVE_ARCH_STRLEN
88extern __kernel_size_t strlen(const char *);
89#endif
90#ifndef __HAVE_ARCH_STRNLEN
91extern __kernel_size_t strnlen(const char *,__kernel_size_t);
92#endif
93#ifndef __HAVE_ARCH_STRPBRK
94extern char * strpbrk(const char *,const char *);
95#endif
96#ifndef __HAVE_ARCH_STRSEP
97extern char * strsep(char **,const char *);
98#endif
99#ifndef __HAVE_ARCH_STRSPN
100extern __kernel_size_t strspn(const char *,const char *);
101#endif
102#ifndef __HAVE_ARCH_STRCSPN
103extern __kernel_size_t strcspn(const char *,const char *);
104#endif
105
106#ifndef __HAVE_ARCH_MEMSET
107extern void * memset(void *,int,__kernel_size_t);
108#endif
109
110#ifndef __HAVE_ARCH_MEMSET16
111extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
112#endif
113
114#ifndef __HAVE_ARCH_MEMSET32
115extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
116#endif
117
118#ifndef __HAVE_ARCH_MEMSET64
119extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
120#endif
121
122static inline void *memset_l(unsigned long *p, unsigned long v,
123 __kernel_size_t n)
124{
125 if (BITS_PER_LONG == 32)
126 return memset32((uint32_t *)p, v, n);
127 else
128 return memset64((uint64_t *)p, v, n);
129}
130
131static inline void *memset_p(void **p, void *v, __kernel_size_t n)
132{
133 if (BITS_PER_LONG == 32)
134 return memset32((uint32_t *)p, (uintptr_t)v, n);
135 else
136 return memset64((uint64_t *)p, (uintptr_t)v, n);
137}
138
139extern void **__memcat_p(void **a, void **b);
140#define memcat_p(a, b) ({ \
141 BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)), \
142 "type mismatch in memcat_p()"); \
143 (typeof(*a) *)__memcat_p((void **)(a), (void **)(b)); \
144})
145
146#ifndef __HAVE_ARCH_MEMCPY
147extern void * memcpy(void *,const void *,__kernel_size_t);
148#endif
149#ifndef __HAVE_ARCH_MEMMOVE
150extern void * memmove(void *,const void *,__kernel_size_t);
151#endif
152#ifndef __HAVE_ARCH_MEMSCAN
153extern void * memscan(void *,int,__kernel_size_t);
154#endif
155#ifndef __HAVE_ARCH_MEMCMP
156extern int memcmp(const void *,const void *,__kernel_size_t);
157#endif
158#ifndef __HAVE_ARCH_BCMP
159extern int bcmp(const void *,const void *,__kernel_size_t);
160#endif
161#ifndef __HAVE_ARCH_MEMCHR
162extern void * memchr(const void *,int,__kernel_size_t);
163#endif
164#ifndef __HAVE_ARCH_MEMCPY_MCSAFE
165static inline __must_check unsigned long memcpy_mcsafe(void *dst,
166 const void *src, size_t cnt)
167{
168 memcpy(dst, src, cnt);
169 return 0;
170}
171#endif
172#ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
173static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
174{
175 memcpy(dst, src, cnt);
176}
177#endif
178void *memchr_inv(const void *s, int c, size_t n);
179char *strreplace(char *s, char old, char new);
180
181extern void kfree_const(const void *x);
182
183extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
184extern const char *kstrdup_const(const char *s, gfp_t gfp);
185extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
186extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
187extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
188
189extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
190extern void argv_free(char **argv);
191
192extern bool sysfs_streq(const char *s1, const char *s2);
193extern int kstrtobool(const char *s, bool *res);
194static inline int strtobool(const char *s, bool *res)
195{
196 return kstrtobool(s, res);
197}
198
199int match_string(const char * const *array, size_t n, const char *string);
200int __sysfs_match_string(const char * const *array, size_t n, const char *s);
201
202/**
203 * sysfs_match_string - matches given string in an array
204 * @_a: array of strings
205 * @_s: string to match with
206 *
207 * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
208 */
209#define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
210
211#ifdef CONFIG_BINARY_PRINTF
212int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
213int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
214int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
215#endif
216
217extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
218 const void *from, size_t available);
219
220int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
221
222/**
223 * strstarts - does @str start with @prefix?
224 * @str: string to examine
225 * @prefix: prefix to look for.
226 */
227static inline bool strstarts(const char *str, const char *prefix)
228{
229 return strncmp(str, prefix, strlen(prefix)) == 0;
230}
231
232size_t memweight(const void *ptr, size_t bytes);
233
234/**
235 * memzero_explicit - Fill a region of memory (e.g. sensitive
236 * keying data) with 0s.
237 * @s: Pointer to the start of the area.
238 * @count: The size of the area.
239 *
240 * Note: usually using memset() is just fine (!), but in cases
241 * where clearing out _local_ data at the end of a scope is
242 * necessary, memzero_explicit() should be used instead in
243 * order to prevent the compiler from optimising away zeroing.
244 *
245 * memzero_explicit() doesn't need an arch-specific version as
246 * it just invokes the one of memset() implicitly.
247 */
248static inline void memzero_explicit(void *s, size_t count)
249{
250 memset(s, 0, count);
251 barrier_data(s);
252}
253
254/**
255 * kbasename - return the last part of a pathname.
256 *
257 * @path: path to extract the filename from.
258 */
259static inline const char *kbasename(const char *path)
260{
261 const char *tail = strrchr(path, '/');
262 return tail ? tail + 1 : path;
263}
264
265#define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
266#define __RENAME(x) __asm__(#x)
267
268void fortify_panic(const char *name) __noreturn __cold;
269void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
270void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
271void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter");
272void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
273
274#if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
275
276#ifdef CONFIG_KASAN
277extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
278extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
279extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
280extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
281extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
282extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat);
283extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy);
284extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
285extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
286extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
287#else
288#define __underlying_memchr __builtin_memchr
289#define __underlying_memcmp __builtin_memcmp
290#define __underlying_memcpy __builtin_memcpy
291#define __underlying_memmove __builtin_memmove
292#define __underlying_memset __builtin_memset
293#define __underlying_strcat __builtin_strcat
294#define __underlying_strcpy __builtin_strcpy
295#define __underlying_strlen __builtin_strlen
296#define __underlying_strncat __builtin_strncat
297#define __underlying_strncpy __builtin_strncpy
298#endif
299
300__FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
301{
302 size_t p_size = __builtin_object_size(p, 0);
303 if (__builtin_constant_p(size) && p_size < size)
304 __write_overflow();
305 if (p_size < size)
306 fortify_panic(__func__);
307 return __underlying_strncpy(p, q, size);
308}
309
310__FORTIFY_INLINE char *strcat(char *p, const char *q)
311{
312 size_t p_size = __builtin_object_size(p, 0);
313 if (p_size == (size_t)-1)
314 return __underlying_strcat(p, q);
315 if (strlcat(p, q, p_size) >= p_size)
316 fortify_panic(__func__);
317 return p;
318}
319
320__FORTIFY_INLINE __kernel_size_t strlen(const char *p)
321{
322 __kernel_size_t ret;
323 size_t p_size = __builtin_object_size(p, 0);
324
325 /* Work around gcc excess stack consumption issue */
326 if (p_size == (size_t)-1 ||
327 (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
328 return __underlying_strlen(p);
329 ret = strnlen(p, p_size);
330 if (p_size <= ret)
331 fortify_panic(__func__);
332 return ret;
333}
334
335extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
336__FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
337{
338 size_t p_size = __builtin_object_size(p, 0);
339 __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
340 if (p_size <= ret && maxlen != ret)
341 fortify_panic(__func__);
342 return ret;
343}
344
345/* defined after fortified strlen to reuse it */
346extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
347__FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
348{
349 size_t ret;
350 size_t p_size = __builtin_object_size(p, 0);
351 size_t q_size = __builtin_object_size(q, 0);
352 if (p_size == (size_t)-1 && q_size == (size_t)-1)
353 return __real_strlcpy(p, q, size);
354 ret = strlen(q);
355 if (size) {
356 size_t len = (ret >= size) ? size - 1 : ret;
357 if (__builtin_constant_p(len) && len >= p_size)
358 __write_overflow();
359 if (len >= p_size)
360 fortify_panic(__func__);
361 __underlying_memcpy(p, q, len);
362 p[len] = '\0';
363 }
364 return ret;
365}
366
367/* defined after fortified strlen and strnlen to reuse them */
368__FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
369{
370 size_t p_len, copy_len;
371 size_t p_size = __builtin_object_size(p, 0);
372 size_t q_size = __builtin_object_size(q, 0);
373 if (p_size == (size_t)-1 && q_size == (size_t)-1)
374 return __underlying_strncat(p, q, count);
375 p_len = strlen(p);
376 copy_len = strnlen(q, count);
377 if (p_size < p_len + copy_len + 1)
378 fortify_panic(__func__);
379 __underlying_memcpy(p + p_len, q, copy_len);
380 p[p_len + copy_len] = '\0';
381 return p;
382}
383
384__FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
385{
386 size_t p_size = __builtin_object_size(p, 0);
387 if (__builtin_constant_p(size) && p_size < size)
388 __write_overflow();
389 if (p_size < size)
390 fortify_panic(__func__);
391 return __underlying_memset(p, c, size);
392}
393
394__FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
395{
396 size_t p_size = __builtin_object_size(p, 0);
397 size_t q_size = __builtin_object_size(q, 0);
398 if (__builtin_constant_p(size)) {
399 if (p_size < size)
400 __write_overflow();
401 if (q_size < size)
402 __read_overflow2();
403 }
404 if (p_size < size || q_size < size)
405 fortify_panic(__func__);
406 return __underlying_memcpy(p, q, size);
407}
408
409__FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
410{
411 size_t p_size = __builtin_object_size(p, 0);
412 size_t q_size = __builtin_object_size(q, 0);
413 if (__builtin_constant_p(size)) {
414 if (p_size < size)
415 __write_overflow();
416 if (q_size < size)
417 __read_overflow2();
418 }
419 if (p_size < size || q_size < size)
420 fortify_panic(__func__);
421 return __underlying_memmove(p, q, size);
422}
423
424extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
425__FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
426{
427 size_t p_size = __builtin_object_size(p, 0);
428 if (__builtin_constant_p(size) && p_size < size)
429 __read_overflow();
430 if (p_size < size)
431 fortify_panic(__func__);
432 return __real_memscan(p, c, size);
433}
434
435__FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
436{
437 size_t p_size = __builtin_object_size(p, 0);
438 size_t q_size = __builtin_object_size(q, 0);
439 if (__builtin_constant_p(size)) {
440 if (p_size < size)
441 __read_overflow();
442 if (q_size < size)
443 __read_overflow2();
444 }
445 if (p_size < size || q_size < size)
446 fortify_panic(__func__);
447 return __underlying_memcmp(p, q, size);
448}
449
450__FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
451{
452 size_t p_size = __builtin_object_size(p, 0);
453 if (__builtin_constant_p(size) && p_size < size)
454 __read_overflow();
455 if (p_size < size)
456 fortify_panic(__func__);
457 return __underlying_memchr(p, c, size);
458}
459
460void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
461__FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
462{
463 size_t p_size = __builtin_object_size(p, 0);
464 if (__builtin_constant_p(size) && p_size < size)
465 __read_overflow();
466 if (p_size < size)
467 fortify_panic(__func__);
468 return __real_memchr_inv(p, c, size);
469}
470
471extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
472__FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
473{
474 size_t p_size = __builtin_object_size(p, 0);
475 if (__builtin_constant_p(size) && p_size < size)
476 __read_overflow();
477 if (p_size < size)
478 fortify_panic(__func__);
479 return __real_kmemdup(p, size, gfp);
480}
481
482/* defined after fortified strlen and memcpy to reuse them */
483__FORTIFY_INLINE char *strcpy(char *p, const char *q)
484{
485 size_t p_size = __builtin_object_size(p, 0);
486 size_t q_size = __builtin_object_size(q, 0);
487 if (p_size == (size_t)-1 && q_size == (size_t)-1)
488 return __underlying_strcpy(p, q);
489 memcpy(p, q, strlen(q) + 1);
490 return p;
491}
492
493/* Don't use these outside the FORITFY_SOURCE implementation */
494#undef __underlying_memchr
495#undef __underlying_memcmp
496#undef __underlying_memcpy
497#undef __underlying_memmove
498#undef __underlying_memset
499#undef __underlying_strcat
500#undef __underlying_strcpy
501#undef __underlying_strlen
502#undef __underlying_strncat
503#undef __underlying_strncpy
504#endif
505
506/**
507 * memcpy_and_pad - Copy one buffer to another with padding
508 * @dest: Where to copy to
509 * @dest_len: The destination buffer size
510 * @src: Where to copy from
511 * @count: The number of bytes to copy
512 * @pad: Character to use for padding if space is left in destination.
513 */
514static inline void memcpy_and_pad(void *dest, size_t dest_len,
515 const void *src, size_t count, int pad)
516{
517 if (dest_len > count) {
518 memcpy(dest, src, count);
519 memset(dest + count, pad, dest_len - count);
520 } else
521 memcpy(dest, src, dest_len);
522}
523
524/**
525 * str_has_prefix - Test if a string has a given prefix
526 * @str: The string to test
527 * @prefix: The string to see if @str starts with
528 *
529 * A common way to test a prefix of a string is to do:
530 * strncmp(str, prefix, sizeof(prefix) - 1)
531 *
532 * But this can lead to bugs due to typos, or if prefix is a pointer
533 * and not a constant. Instead use str_has_prefix().
534 *
535 * Returns:
536 * * strlen(@prefix) if @str starts with @prefix
537 * * 0 if @str does not start with @prefix
538 */
539static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
540{
541 size_t len = strlen(prefix);
542 return strncmp(str, prefix, len) == 0 ? len : 0;
543}
544
545#endif /* _LINUX_STRING_H_ */