From f35157417215ec138c920320c746fdb3e04ef1d5 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 4 Jul 2017 17:25:02 +0100 Subject: 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: David Howells Signed-off-by: Al Viro --- mm/util.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'mm/util.c') diff --git a/mm/util.c b/mm/util.c index 26be6407abd7..21ddf90f883d 100644 --- a/mm/util.c +++ b/mm/util.c @@ -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 * -- cgit v1.2.3-70-g09d2