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Commit f3515741 authored by David Howells's avatar David Howells Committed by Al Viro
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Provide a function to create a NUL-terminated string from unterminated data 



Provide a function, kmemdup_nul(), that will create a NUL-terminated string
from an unterminated character array where the length is known in advance.

This is better than kstrndup() in situations where we already know the
string length as the strnlen() in kstrndup() is superfluous.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c0bc126f

include/linux/string.h

+1 −0
Original line number Diff line number Diff line
@@ -131,6 +131,7 @@ extern char *kstrdup(const char *s, gfp_t gfp) __malloc; 
extern const char *kstrdup_const(const char *s, gfp_t gfp);

extern char *kstrndup(const char *s, size_t len, gfp_t gfp);

extern void *kmemdup(const void *src, size_t len, gfp_t gfp);

extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);



extern char **argv_split(gfp_t gfp, const char *str, int *argcp);

extern void argv_free(char **argv);

mm/util.c

+24 −0
Original line number Diff line number Diff line
@@ -83,6 +83,8 @@ EXPORT_SYMBOL(kstrdup_const); 
 * @s: the string to duplicate

 * @max: read at most @max chars from @s

 * @gfp: the GFP mask used in the kmalloc() call when allocating memory

 *

 * Note: Use kmemdup_nul() instead if the size is known exactly.

 */

char *kstrndup(const char *s, size_t max, gfp_t gfp)

{
@@ -120,6 +122,28 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp) 
}

EXPORT_SYMBOL(kmemdup);



/**

 * kmemdup_nul - Create a NUL-terminated string from unterminated data

 * @s: The data to stringify

 * @len: The size of the data

 * @gfp: the GFP mask used in the kmalloc() call when allocating memory

 */

char *kmemdup_nul(const char *s, size_t len, gfp_t gfp)

{

	char *buf;



	if (!s)

		return NULL;



	buf = kmalloc_track_caller(len + 1, gfp);

	if (buf) {

		memcpy(buf, s, len);

		buf[len] = '\0';

	}

	return buf;

}

EXPORT_SYMBOL(kmemdup_nul);



/**

 * memdup_user - duplicate memory region from user space

 *