add kstrndup
Add a kstrndup function, modelled on strndup. Like strndup this
returns a string copied into its own allocated memory, but it copies
no more than the specified number of bytes from the source.
Remove private strndup() from irda code.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@mandriva.com>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Panagiotis Issaris <takis@issaris.org>
Cc: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
diff --git a/mm/util.c b/mm/util.c
index 78f3783..bf340d8 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -6,7 +6,6 @@
/**
* kstrdup - allocate space for and copy an existing string
- *
* @s: the string to duplicate
* @gfp: the GFP mask used in the kmalloc() call when allocating memory
*/
@@ -27,6 +26,30 @@
EXPORT_SYMBOL(kstrdup);
/**
+ * kstrndup - allocate space for and copy an existing string
+ * @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
+ */
+char *kstrndup(const char *s, size_t max, gfp_t gfp)
+{
+ size_t len;
+ char *buf;
+
+ if (!s)
+ return NULL;
+
+ len = strnlen(s, max);
+ buf = kmalloc_track_caller(len+1, gfp);
+ if (buf) {
+ memcpy(buf, s, len);
+ buf[len] = '\0';
+ }
+ return buf;
+}
+EXPORT_SYMBOL(kstrndup);
+
+/**
* kmemdup - duplicate region of memory
*
* @src: memory region to duplicate
@@ -80,7 +103,6 @@
/*
* strndup_user - duplicate an existing string from user space
- *
* @s: The string to duplicate
* @n: Maximum number of bytes to copy, including the trailing NUL.
*/
