1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_STRING_H_
3 #define _LINUX_STRING_H_
4
5 #include <linux/compiler.h> /* for inline */
6 #include <linux/types.h> /* for size_t */
7 #include <linux/stddef.h> /* for NULL */
8 #include <linux/errno.h> /* for E2BIG */
9 #include <linux/stdarg.h>
10 #include <uapi/linux/string.h>
11
12 extern char *strndup_user(const char __user *, long);
13 extern void *memdup_user(const void __user *, size_t);
14 extern void *vmemdup_user(const void __user *, size_t);
15 extern 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
23 extern char * strcpy(char *,const char *);
24 #endif
25 #ifndef __HAVE_ARCH_STRNCPY
26 extern char * strncpy(char *,const char *, __kernel_size_t);
27 #endif
28 #ifndef __HAVE_ARCH_STRLCPY
29 size_t strlcpy(char *, const char *, size_t);
30 #endif
31 #ifndef __HAVE_ARCH_STRSCPY
32 ssize_t strscpy(char *, const char *, size_t);
33 #endif
34
35 /* Wraps calls to strscpy()/memset(), no arch specific code required */
36 ssize_t strscpy_pad(char *dest, const char *src, size_t count);
37
38 #ifndef __HAVE_ARCH_STRCAT
39 extern char * strcat(char *, const char *);
40 #endif
41 #ifndef __HAVE_ARCH_STRNCAT
42 extern char * strncat(char *, const char *, __kernel_size_t);
43 #endif
44 #ifndef __HAVE_ARCH_STRLCAT
45 extern size_t strlcat(char *, const char *, __kernel_size_t);
46 #endif
47 #ifndef __HAVE_ARCH_STRCMP
48 extern int strcmp(const char *,const char *);
49 #endif
50 #ifndef __HAVE_ARCH_STRNCMP
51 extern int strncmp(const char *,const char *,__kernel_size_t);
52 #endif
53 #ifndef __HAVE_ARCH_STRCASECMP
54 extern int strcasecmp(const char *s1, const char *s2);
55 #endif
56 #ifndef __HAVE_ARCH_STRNCASECMP
57 extern int strncasecmp(const char *s1, const char *s2, size_t n);
58 #endif
59 #ifndef __HAVE_ARCH_STRCHR
60 extern char * strchr(const char *,int);
61 #endif
62 #ifndef __HAVE_ARCH_STRCHRNUL
63 extern char * strchrnul(const char *,int);
64 #endif
65 extern char * strnchrnul(const char *, size_t, int);
66 #ifndef __HAVE_ARCH_STRNCHR
67 extern char * strnchr(const char *, size_t, int);
68 #endif
69 #ifndef __HAVE_ARCH_STRRCHR
70 extern char * strrchr(const char *,int);
71 #endif
72 extern char * __must_check skip_spaces(const char *);
73
74 extern char *strim(char *);
75
strstrip(char * str)76 static inline __must_check char *strstrip(char *str)
77 {
78 return strim(str);
79 }
80
81 #ifndef __HAVE_ARCH_STRSTR
82 extern char * strstr(const char *, const char *);
83 #endif
84 #ifndef __HAVE_ARCH_STRNSTR
85 extern char * strnstr(const char *, const char *, size_t);
86 #endif
87 #ifndef __HAVE_ARCH_STRLEN
88 extern __kernel_size_t strlen(const char *);
89 #endif
90 #ifndef __HAVE_ARCH_STRNLEN
91 extern __kernel_size_t strnlen(const char *,__kernel_size_t);
92 #endif
93 #ifndef __HAVE_ARCH_STRPBRK
94 extern char * strpbrk(const char *,const char *);
95 #endif
96 #ifndef __HAVE_ARCH_STRSEP
97 extern char * strsep(char **,const char *);
98 #endif
99 #ifndef __HAVE_ARCH_STRSPN
100 extern __kernel_size_t strspn(const char *,const char *);
101 #endif
102 #ifndef __HAVE_ARCH_STRCSPN
103 extern __kernel_size_t strcspn(const char *,const char *);
104 #endif
105
106 #ifndef __HAVE_ARCH_MEMSET
107 extern void * memset(void *,int,__kernel_size_t);
108 #endif
109
110 #ifndef __HAVE_ARCH_MEMSET16
111 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
112 #endif
113
114 #ifndef __HAVE_ARCH_MEMSET32
115 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
116 #endif
117
118 #ifndef __HAVE_ARCH_MEMSET64
119 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
120 #endif
121
memset_l(unsigned long * p,unsigned long v,__kernel_size_t n)122 static 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
memset_p(void ** p,void * v,__kernel_size_t n)131 static 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
139 extern 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
147 extern void * memcpy(void *,const void *,__kernel_size_t);
148 #endif
149 #ifndef __HAVE_ARCH_MEMMOVE
150 extern void * memmove(void *,const void *,__kernel_size_t);
151 #endif
152 #ifndef __HAVE_ARCH_MEMSCAN
153 extern void * memscan(void *,int,__kernel_size_t);
154 #endif
155 #ifndef __HAVE_ARCH_MEMCMP
156 extern int memcmp(const void *,const void *,__kernel_size_t);
157 #endif
158 #ifndef __HAVE_ARCH_BCMP
159 extern int bcmp(const void *,const void *,__kernel_size_t);
160 #endif
161 #ifndef __HAVE_ARCH_MEMCHR
162 extern void * memchr(const void *,int,__kernel_size_t);
163 #endif
164 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
memcpy_flushcache(void * dst,const void * src,size_t cnt)165 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
166 {
167 memcpy(dst, src, cnt);
168 }
169 #endif
170
171 void *memchr_inv(const void *s, int c, size_t n);
172 char *strreplace(char *s, char old, char new);
173
174 extern void kfree_const(const void *x);
175
176 extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
177 extern const char *kstrdup_const(const char *s, gfp_t gfp);
178 extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
179 extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
180 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
181
182 extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
183 extern void argv_free(char **argv);
184
185 extern bool sysfs_streq(const char *s1, const char *s2);
186 int match_string(const char * const *array, size_t n, const char *string);
187 int __sysfs_match_string(const char * const *array, size_t n, const char *s);
188
189 /**
190 * sysfs_match_string - matches given string in an array
191 * @_a: array of strings
192 * @_s: string to match with
193 *
194 * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
195 */
196 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
197
198 #ifdef CONFIG_BINARY_PRINTF
199 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
200 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
201 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
202 #endif
203
204 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
205 const void *from, size_t available);
206
207 int ptr_to_hashval(const void *ptr, unsigned long *hashval_out);
208
209 /**
210 * strstarts - does @str start with @prefix?
211 * @str: string to examine
212 * @prefix: prefix to look for.
213 */
strstarts(const char * str,const char * prefix)214 static inline bool strstarts(const char *str, const char *prefix)
215 {
216 return strncmp(str, prefix, strlen(prefix)) == 0;
217 }
218
219 size_t memweight(const void *ptr, size_t bytes);
220
221 /**
222 * memzero_explicit - Fill a region of memory (e.g. sensitive
223 * keying data) with 0s.
224 * @s: Pointer to the start of the area.
225 * @count: The size of the area.
226 *
227 * Note: usually using memset() is just fine (!), but in cases
228 * where clearing out _local_ data at the end of a scope is
229 * necessary, memzero_explicit() should be used instead in
230 * order to prevent the compiler from optimising away zeroing.
231 *
232 * memzero_explicit() doesn't need an arch-specific version as
233 * it just invokes the one of memset() implicitly.
234 */
memzero_explicit(void * s,size_t count)235 static inline void memzero_explicit(void *s, size_t count)
236 {
237 memset(s, 0, count);
238 barrier_data(s);
239 }
240
241 /**
242 * kbasename - return the last part of a pathname.
243 *
244 * @path: path to extract the filename from.
245 */
kbasename(const char * path)246 static inline const char *kbasename(const char *path)
247 {
248 const char *tail = strrchr(path, '/');
249 return tail ? tail + 1 : path;
250 }
251
252 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
253 #include <linux/fortify-string.h>
254 #endif
255 #ifndef unsafe_memcpy
256 #define unsafe_memcpy(dst, src, bytes, justification) \
257 memcpy(dst, src, bytes)
258 #endif
259
260 void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count,
261 int pad);
262
263 /**
264 * strtomem_pad - Copy NUL-terminated string to non-NUL-terminated buffer
265 *
266 * @dest: Pointer of destination character array (marked as __nonstring)
267 * @src: Pointer to NUL-terminated string
268 * @pad: Padding character to fill any remaining bytes of @dest after copy
269 *
270 * This is a replacement for strncpy() uses where the destination is not
271 * a NUL-terminated string, but with bounds checking on the source size, and
272 * an explicit padding character. If padding is not required, use strtomem().
273 *
274 * Note that the size of @dest is not an argument, as the length of @dest
275 * must be discoverable by the compiler.
276 */
277 #define strtomem_pad(dest, src, pad) do { \
278 const size_t _dest_len = __builtin_object_size(dest, 1); \
279 \
280 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
281 _dest_len == (size_t)-1); \
282 memcpy_and_pad(dest, _dest_len, src, strnlen(src, _dest_len), pad); \
283 } while (0)
284
285 /**
286 * strtomem - Copy NUL-terminated string to non-NUL-terminated buffer
287 *
288 * @dest: Pointer of destination character array (marked as __nonstring)
289 * @src: Pointer to NUL-terminated string
290 *
291 * This is a replacement for strncpy() uses where the destination is not
292 * a NUL-terminated string, but with bounds checking on the source size, and
293 * without trailing padding. If padding is required, use strtomem_pad().
294 *
295 * Note that the size of @dest is not an argument, as the length of @dest
296 * must be discoverable by the compiler.
297 */
298 #define strtomem(dest, src) do { \
299 const size_t _dest_len = __builtin_object_size(dest, 1); \
300 \
301 BUILD_BUG_ON(!__builtin_constant_p(_dest_len) || \
302 _dest_len == (size_t)-1); \
303 memcpy(dest, src, min(_dest_len, strnlen(src, _dest_len))); \
304 } while (0)
305
306 /**
307 * memset_after - Set a value after a struct member to the end of a struct
308 *
309 * @obj: Address of target struct instance
310 * @v: Byte value to repeatedly write
311 * @member: after which struct member to start writing bytes
312 *
313 * This is good for clearing padding following the given member.
314 */
315 #define memset_after(obj, v, member) \
316 ({ \
317 u8 *__ptr = (u8 *)(obj); \
318 typeof(v) __val = (v); \
319 memset(__ptr + offsetofend(typeof(*(obj)), member), __val, \
320 sizeof(*(obj)) - offsetofend(typeof(*(obj)), member)); \
321 })
322
323 /**
324 * memset_startat - Set a value starting at a member to the end of a struct
325 *
326 * @obj: Address of target struct instance
327 * @v: Byte value to repeatedly write
328 * @member: struct member to start writing at
329 *
330 * Note that if there is padding between the prior member and the target
331 * member, memset_after() should be used to clear the prior padding.
332 */
333 #define memset_startat(obj, v, member) \
334 ({ \
335 u8 *__ptr = (u8 *)(obj); \
336 typeof(v) __val = (v); \
337 memset(__ptr + offsetof(typeof(*(obj)), member), __val, \
338 sizeof(*(obj)) - offsetof(typeof(*(obj)), member)); \
339 })
340
341 /**
342 * str_has_prefix - Test if a string has a given prefix
343 * @str: The string to test
344 * @prefix: The string to see if @str starts with
345 *
346 * A common way to test a prefix of a string is to do:
347 * strncmp(str, prefix, sizeof(prefix) - 1)
348 *
349 * But this can lead to bugs due to typos, or if prefix is a pointer
350 * and not a constant. Instead use str_has_prefix().
351 *
352 * Returns:
353 * * strlen(@prefix) if @str starts with @prefix
354 * * 0 if @str does not start with @prefix
355 */
str_has_prefix(const char * str,const char * prefix)356 static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
357 {
358 size_t len = strlen(prefix);
359 return strncmp(str, prefix, len) == 0 ? len : 0;
360 }
361
362 #endif /* _LINUX_STRING_H_ */
363
