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TOMOYO Linux Cross Reference
Linux/include/linux/string.h

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  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 
 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 #ifndef __HAVE_ARCH_STRNCHR
 66 extern char * strnchr(const char *, size_t, int);
 67 #endif
 68 #ifndef __HAVE_ARCH_STRRCHR
 69 extern char * strrchr(const char *,int);
 70 #endif
 71 extern char * __must_check skip_spaces(const char *);
 72 
 73 extern char *strim(char *);
 74 
 75 static inline __must_check char *strstrip(char *str)
 76 {
 77         return strim(str);
 78 }
 79 
 80 #ifndef __HAVE_ARCH_STRSTR
 81 extern char * strstr(const char *, const char *);
 82 #endif
 83 #ifndef __HAVE_ARCH_STRNSTR
 84 extern char * strnstr(const char *, const char *, size_t);
 85 #endif
 86 #ifndef __HAVE_ARCH_STRLEN
 87 extern __kernel_size_t strlen(const char *);
 88 #endif
 89 #ifndef __HAVE_ARCH_STRNLEN
 90 extern __kernel_size_t strnlen(const char *,__kernel_size_t);
 91 #endif
 92 #ifndef __HAVE_ARCH_STRPBRK
 93 extern char * strpbrk(const char *,const char *);
 94 #endif
 95 #ifndef __HAVE_ARCH_STRSEP
 96 extern char * strsep(char **,const char *);
 97 #endif
 98 #ifndef __HAVE_ARCH_STRSPN
 99 extern __kernel_size_t strspn(const char *,const char *);
100 #endif
101 #ifndef __HAVE_ARCH_STRCSPN
102 extern __kernel_size_t strcspn(const char *,const char *);
103 #endif
104 
105 #ifndef __HAVE_ARCH_MEMSET
106 extern void * memset(void *,int,__kernel_size_t);
107 #endif
108 
109 #ifndef __HAVE_ARCH_MEMSET16
110 extern void *memset16(uint16_t *, uint16_t, __kernel_size_t);
111 #endif
112 
113 #ifndef __HAVE_ARCH_MEMSET32
114 extern void *memset32(uint32_t *, uint32_t, __kernel_size_t);
115 #endif
116 
117 #ifndef __HAVE_ARCH_MEMSET64
118 extern void *memset64(uint64_t *, uint64_t, __kernel_size_t);
119 #endif
120 
121 static inline void *memset_l(unsigned long *p, unsigned long v,
122                 __kernel_size_t n)
123 {
124         if (BITS_PER_LONG == 32)
125                 return memset32((uint32_t *)p, v, n);
126         else
127                 return memset64((uint64_t *)p, v, n);
128 }
129 
130 static inline void *memset_p(void **p, void *v, __kernel_size_t n)
131 {
132         if (BITS_PER_LONG == 32)
133                 return memset32((uint32_t *)p, (uintptr_t)v, n);
134         else
135                 return memset64((uint64_t *)p, (uintptr_t)v, n);
136 }
137 
138 extern void **__memcat_p(void **a, void **b);
139 #define memcat_p(a, b) ({                                       \
140         BUILD_BUG_ON_MSG(!__same_type(*(a), *(b)),              \
141                          "type mismatch in memcat_p()");        \
142         (typeof(*a) *)__memcat_p((void **)(a), (void **)(b));   \
143 })
144 
145 #ifndef __HAVE_ARCH_MEMCPY
146 extern void * memcpy(void *,const void *,__kernel_size_t);
147 #endif
148 #ifndef __HAVE_ARCH_MEMMOVE
149 extern void * memmove(void *,const void *,__kernel_size_t);
150 #endif
151 #ifndef __HAVE_ARCH_MEMSCAN
152 extern void * memscan(void *,int,__kernel_size_t);
153 #endif
154 #ifndef __HAVE_ARCH_MEMCMP
155 extern int memcmp(const void *,const void *,__kernel_size_t);
156 #endif
157 #ifndef __HAVE_ARCH_BCMP
158 extern int bcmp(const void *,const void *,__kernel_size_t);
159 #endif
160 #ifndef __HAVE_ARCH_MEMCHR
161 extern void * memchr(const void *,int,__kernel_size_t);
162 #endif
163 #ifndef __HAVE_ARCH_MEMCPY_MCSAFE
164 static inline __must_check unsigned long memcpy_mcsafe(void *dst,
165                 const void *src, size_t cnt)
166 {
167         memcpy(dst, src, cnt);
168         return 0;
169 }
170 #endif
171 #ifndef __HAVE_ARCH_MEMCPY_FLUSHCACHE
172 static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
173 {
174         memcpy(dst, src, cnt);
175 }
176 #endif
177 void *memchr_inv(const void *s, int c, size_t n);
178 char *strreplace(char *s, char old, char new);
179 
180 extern void kfree_const(const void *x);
181 
182 extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
183 extern const char *kstrdup_const(const char *s, gfp_t gfp);
184 extern char *kstrndup(const char *s, size_t len, gfp_t gfp);
185 extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
186 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
187 
188 extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
189 extern void argv_free(char **argv);
190 
191 extern bool sysfs_streq(const char *s1, const char *s2);
192 extern int kstrtobool(const char *s, bool *res);
193 static inline int strtobool(const char *s, bool *res)
194 {
195         return kstrtobool(s, res);
196 }
197 
198 int match_string(const char * const *array, size_t n, const char *string);
199 int __sysfs_match_string(const char * const *array, size_t n, const char *s);
200 
201 /**
202  * sysfs_match_string - matches given string in an array
203  * @_a: array of strings
204  * @_s: string to match with
205  *
206  * Helper for __sysfs_match_string(). Calculates the size of @a automatically.
207  */
208 #define sysfs_match_string(_a, _s) __sysfs_match_string(_a, ARRAY_SIZE(_a), _s)
209 
210 #ifdef CONFIG_BINARY_PRINTF
211 int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args);
212 int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf);
213 int bprintf(u32 *bin_buf, size_t size, const char *fmt, ...) __printf(3, 4);
214 #endif
215 
216 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
217                                        const void *from, size_t available);
218 
219 /**
220  * strstarts - does @str start with @prefix?
221  * @str: string to examine
222  * @prefix: prefix to look for.
223  */
224 static inline bool strstarts(const char *str, const char *prefix)
225 {
226         return strncmp(str, prefix, strlen(prefix)) == 0;
227 }
228 
229 size_t memweight(const void *ptr, size_t bytes);
230 void memzero_explicit(void *s, size_t count);
231 
232 /**
233  * kbasename - return the last part of a pathname.
234  *
235  * @path: path to extract the filename from.
236  */
237 static inline const char *kbasename(const char *path)
238 {
239         const char *tail = strrchr(path, '/');
240         return tail ? tail + 1 : path;
241 }
242 
243 #define __FORTIFY_INLINE extern __always_inline __attribute__((gnu_inline))
244 #define __RENAME(x) __asm__(#x)
245 
246 void fortify_panic(const char *name) __noreturn __cold;
247 void __read_overflow(void) __compiletime_error("detected read beyond size of object passed as 1st parameter");
248 void __read_overflow2(void) __compiletime_error("detected read beyond size of object passed as 2nd parameter");
249 void __read_overflow3(void) __compiletime_error("detected read beyond size of object passed as 3rd parameter");
250 void __write_overflow(void) __compiletime_error("detected write beyond size of object passed as 1st parameter");
251 
252 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
253 __FORTIFY_INLINE char *strncpy(char *p, const char *q, __kernel_size_t size)
254 {
255         size_t p_size = __builtin_object_size(p, 0);
256         if (__builtin_constant_p(size) && p_size < size)
257                 __write_overflow();
258         if (p_size < size)
259                 fortify_panic(__func__);
260         return __builtin_strncpy(p, q, size);
261 }
262 
263 __FORTIFY_INLINE char *strcat(char *p, const char *q)
264 {
265         size_t p_size = __builtin_object_size(p, 0);
266         if (p_size == (size_t)-1)
267                 return __builtin_strcat(p, q);
268         if (strlcat(p, q, p_size) >= p_size)
269                 fortify_panic(__func__);
270         return p;
271 }
272 
273 __FORTIFY_INLINE __kernel_size_t strlen(const char *p)
274 {
275         __kernel_size_t ret;
276         size_t p_size = __builtin_object_size(p, 0);
277 
278         /* Work around gcc excess stack consumption issue */
279         if (p_size == (size_t)-1 ||
280             (__builtin_constant_p(p[p_size - 1]) && p[p_size - 1] == '\0'))
281                 return __builtin_strlen(p);
282         ret = strnlen(p, p_size);
283         if (p_size <= ret)
284                 fortify_panic(__func__);
285         return ret;
286 }
287 
288 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
289 __FORTIFY_INLINE __kernel_size_t strnlen(const char *p, __kernel_size_t maxlen)
290 {
291         size_t p_size = __builtin_object_size(p, 0);
292         __kernel_size_t ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
293         if (p_size <= ret && maxlen != ret)
294                 fortify_panic(__func__);
295         return ret;
296 }
297 
298 /* defined after fortified strlen to reuse it */
299 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy);
300 __FORTIFY_INLINE size_t strlcpy(char *p, const char *q, size_t size)
301 {
302         size_t ret;
303         size_t p_size = __builtin_object_size(p, 0);
304         size_t q_size = __builtin_object_size(q, 0);
305         if (p_size == (size_t)-1 && q_size == (size_t)-1)
306                 return __real_strlcpy(p, q, size);
307         ret = strlen(q);
308         if (size) {
309                 size_t len = (ret >= size) ? size - 1 : ret;
310                 if (__builtin_constant_p(len) && len >= p_size)
311                         __write_overflow();
312                 if (len >= p_size)
313                         fortify_panic(__func__);
314                 __builtin_memcpy(p, q, len);
315                 p[len] = '\0';
316         }
317         return ret;
318 }
319 
320 /* defined after fortified strlen and strnlen to reuse them */
321 __FORTIFY_INLINE char *strncat(char *p, const char *q, __kernel_size_t count)
322 {
323         size_t p_len, copy_len;
324         size_t p_size = __builtin_object_size(p, 0);
325         size_t q_size = __builtin_object_size(q, 0);
326         if (p_size == (size_t)-1 && q_size == (size_t)-1)
327                 return __builtin_strncat(p, q, count);
328         p_len = strlen(p);
329         copy_len = strnlen(q, count);
330         if (p_size < p_len + copy_len + 1)
331                 fortify_panic(__func__);
332         __builtin_memcpy(p + p_len, q, copy_len);
333         p[p_len + copy_len] = '\0';
334         return p;
335 }
336 
337 __FORTIFY_INLINE void *memset(void *p, int c, __kernel_size_t size)
338 {
339         size_t p_size = __builtin_object_size(p, 0);
340         if (__builtin_constant_p(size) && p_size < size)
341                 __write_overflow();
342         if (p_size < size)
343                 fortify_panic(__func__);
344         return __builtin_memset(p, c, size);
345 }
346 
347 __FORTIFY_INLINE void *memcpy(void *p, const void *q, __kernel_size_t size)
348 {
349         size_t p_size = __builtin_object_size(p, 0);
350         size_t q_size = __builtin_object_size(q, 0);
351         if (__builtin_constant_p(size)) {
352                 if (p_size < size)
353                         __write_overflow();
354                 if (q_size < size)
355                         __read_overflow2();
356         }
357         if (p_size < size || q_size < size)
358                 fortify_panic(__func__);
359         return __builtin_memcpy(p, q, size);
360 }
361 
362 __FORTIFY_INLINE void *memmove(void *p, const void *q, __kernel_size_t size)
363 {
364         size_t p_size = __builtin_object_size(p, 0);
365         size_t q_size = __builtin_object_size(q, 0);
366         if (__builtin_constant_p(size)) {
367                 if (p_size < size)
368                         __write_overflow();
369                 if (q_size < size)
370                         __read_overflow2();
371         }
372         if (p_size < size || q_size < size)
373                 fortify_panic(__func__);
374         return __builtin_memmove(p, q, size);
375 }
376 
377 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
378 __FORTIFY_INLINE void *memscan(void *p, int c, __kernel_size_t size)
379 {
380         size_t p_size = __builtin_object_size(p, 0);
381         if (__builtin_constant_p(size) && p_size < size)
382                 __read_overflow();
383         if (p_size < size)
384                 fortify_panic(__func__);
385         return __real_memscan(p, c, size);
386 }
387 
388 __FORTIFY_INLINE int memcmp(const void *p, const void *q, __kernel_size_t size)
389 {
390         size_t p_size = __builtin_object_size(p, 0);
391         size_t q_size = __builtin_object_size(q, 0);
392         if (__builtin_constant_p(size)) {
393                 if (p_size < size)
394                         __read_overflow();
395                 if (q_size < size)
396                         __read_overflow2();
397         }
398         if (p_size < size || q_size < size)
399                 fortify_panic(__func__);
400         return __builtin_memcmp(p, q, size);
401 }
402 
403 __FORTIFY_INLINE void *memchr(const void *p, int c, __kernel_size_t size)
404 {
405         size_t p_size = __builtin_object_size(p, 0);
406         if (__builtin_constant_p(size) && p_size < size)
407                 __read_overflow();
408         if (p_size < size)
409                 fortify_panic(__func__);
410         return __builtin_memchr(p, c, size);
411 }
412 
413 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
414 __FORTIFY_INLINE void *memchr_inv(const void *p, int c, size_t size)
415 {
416         size_t p_size = __builtin_object_size(p, 0);
417         if (__builtin_constant_p(size) && p_size < size)
418                 __read_overflow();
419         if (p_size < size)
420                 fortify_panic(__func__);
421         return __real_memchr_inv(p, c, size);
422 }
423 
424 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup);
425 __FORTIFY_INLINE void *kmemdup(const void *p, size_t size, gfp_t gfp)
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_kmemdup(p, size, gfp);
433 }
434 
435 /* defined after fortified strlen and memcpy to reuse them */
436 __FORTIFY_INLINE char *strcpy(char *p, const char *q)
437 {
438         size_t p_size = __builtin_object_size(p, 0);
439         size_t q_size = __builtin_object_size(q, 0);
440         if (p_size == (size_t)-1 && q_size == (size_t)-1)
441                 return __builtin_strcpy(p, q);
442         memcpy(p, q, strlen(q) + 1);
443         return p;
444 }
445 
446 #endif
447 
448 /**
449  * memcpy_and_pad - Copy one buffer to another with padding
450  * @dest: Where to copy to
451  * @dest_len: The destination buffer size
452  * @src: Where to copy from
453  * @count: The number of bytes to copy
454  * @pad: Character to use for padding if space is left in destination.
455  */
456 static inline void memcpy_and_pad(void *dest, size_t dest_len,
457                                   const void *src, size_t count, int pad)
458 {
459         if (dest_len > count) {
460                 memcpy(dest, src, count);
461                 memset(dest + count, pad,  dest_len - count);
462         } else
463                 memcpy(dest, src, dest_len);
464 }
465 
466 /**
467  * str_has_prefix - Test if a string has a given prefix
468  * @str: The string to test
469  * @prefix: The string to see if @str starts with
470  *
471  * A common way to test a prefix of a string is to do:
472  *  strncmp(str, prefix, sizeof(prefix) - 1)
473  *
474  * But this can lead to bugs due to typos, or if prefix is a pointer
475  * and not a constant. Instead use str_has_prefix().
476  *
477  * Returns: 0 if @str does not start with @prefix
478          strlen(@prefix) if @str does start with @prefix
479  */
480 static __always_inline size_t str_has_prefix(const char *str, const char *prefix)
481 {
482         size_t len = strlen(prefix);
483         return strncmp(str, prefix, len) == 0 ? len : 0;
484 }
485 
486 #endif /* _LINUX_STRING_H_ */
487 

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