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string.h revision 1.6 
      1 /*	$NetBSD: string.h,v 1.6 2021/12/19 00:48:30 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _LINUX_STRING_H_
     33 #define _LINUX_STRING_H_
     34 
     35 #include <sys/types.h>
     36 #include <sys/cdefs.h>
     37 #include <sys/errno.h>
     38 #include <sys/null.h>
     39 
     40 #include <linux/slab.h>
     41 
     42 static inline void *
     43 memchr_inv(const void *buffer, int c, size_t len)
     44 {
     45 	const uint8_t byte = c;	/* XXX lose */
     46 	const char *p;
     47 
     48 	for (p = buffer; len-- > 0; p++)
     49 		if (*p != byte)
     50 			return __UNCONST(p);
     51 
     52 	return NULL;
     53 }
     54 
     55 static inline void *
     56 kmemdup(const void *src, size_t len, gfp_t gfp)
     57 {
     58 	void *dst;
     59 
     60 	dst = kmalloc(len, gfp);
     61 	if (dst == NULL)
     62 		return NULL;
     63 
     64 	(void)memcpy(dst, src, len);
     65 	return dst;
     66 }
     67 
     68 static inline char *
     69 kstrndup(const char *src, size_t maxlen, gfp_t gfp)
     70 {
     71 	char *dst;
     72 	size_t len;
     73 
     74 	if (src == NULL)
     75 		return NULL;
     76 
     77 	len = strnlen(src, maxlen);
     78 	dst = kmalloc(len + 1, gfp);
     79 	if (dst == NULL)
     80 		return NULL;
     81 
     82 	(void)memcpy(dst, src, len);
     83 	dst[len] = '\0';
     84 
     85 	return dst;
     86 }
     87 
     88 static inline char *
     89 kstrdup(const char *src, gfp_t gfp)
     90 {
     91 
     92 	if (src == NULL)
     93 		return NULL;
     94 	return kstrndup(src, strlen(src), gfp);
     95 }
     96 
     97 static inline ssize_t
     98 strscpy(char *dst, const char *src, size_t dstsize)
     99 {
    100 	size_t n = dstsize;
    101 
    102 	/* If no space for a NUL terminator, fail.  */
    103 	if (n == 0)
    104 		return -E2BIG;
    105 
    106 	/* Copy until we get a NUL terminator or the end of the buffer.  */
    107 	while ((*dst++ = *src++) != '\0') {
    108 		if (__predict_false(--n == 0)) {
    109 			dst[-1] = '\0'; /* NUL-terminate */
    110 			return -E2BIG;
    111 		}
    112 	}
    113 
    114 	/* Return the number of bytes copied, excluding NUL.  */
    115 	return dstsize - n;
    116 }
    117 
    118 #endif  /* _LINUX_STRING_H_ */
    119