[PATCH] kernfs: Replace strncpy with memcpy

[PATCH] kernfs: Replace strncpy with memcpy

[Guenter Roeck]

gcc 8.1.0 complains:

fs/kernfs/symlink.c:91:3: warning:
	'strncpy' output truncated before terminating nul copying
	as many bytes from a string as its length
fs/kernfs/symlink.c: In function 'kernfs_iop_get_link':
fs/kernfs/symlink.c:88:14: note: length computed here

Using strncpy() is indeed less than perfect since the length of data to
be copied has already been determined with strlen(). Replace strncpy()
with memcpy() to address the warning and optimize the code a little.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 fs/kernfs/symlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index 08ccabd7047f..5145ae2f0572 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -88,7 +88,7 @@ static int kernfs_get_target_path(struct kernfs_node *parent,
 		int slen = strlen(kn->name);
 
 		len -= slen;
-		strncpy(s + len, kn->name, slen);
+		memcpy(s + len, kn->name, slen);
 		if (len)
 			s[--len] = '/';
 
-- 
2.7.4

Re: [PATCH] kernfs: Replace strncpy with memcpy

[Tejun Heo]

On Sun, Jul 01, 2018 at 01:57:13PM -0700, Guenter Roeck wrote:
> gcc 8.1.0 complains:
> 
> fs/kernfs/symlink.c:91:3: warning:
> 	'strncpy' output truncated before terminating nul copying
> 	as many bytes from a string as its length
> fs/kernfs/symlink.c: In function 'kernfs_iop_get_link':
> fs/kernfs/symlink.c:88:14: note: length computed here
> 
> Using strncpy() is indeed less than perfect since the length of data to
> be copied has already been determined with strlen(). Replace strncpy()
> with memcpy() to address the warning and optimize the code a little.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun