[PATCH] fs/hfsplus: use memcpy() instead of strncpy()

[PATCH] fs/hfsplus: use memcpy() instead of strncpy()

[Xiongfeng Wang]

From: Xiongfeng Wang <xiongfeng.wang@linaro.org>

gcc-8 reports

inlined from 'copy_name' at fs/hfsplus/xattr.c:416:3:
./include/linux/string.h:245:9: warning: '__builtin_strncpy' output
truncated before terminating nul copying 4 bytes from a string of the
same length [-Wstringop-truncation]

Since we don't need to copy '\0', we can just use memcpy() to avoid this
warning.

Signed-off-by: Xiongfeng Wang <xiongfeng.wang@linaro.org>
---
 fs/hfsplus/xattr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index e538b75..0dc8a65 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -413,7 +413,7 @@ static int copy_name(char *buffer, const char *xattr_name, int name_len)
 	int offset = 0;
 
 	if (!is_known_namespace(xattr_name)) {
-		strncpy(buffer, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN);
+		memcpy(buffer, XATTR_MAC_OSX_PREFIX, XATTR_MAC_OSX_PREFIX_LEN);
 		offset += XATTR_MAC_OSX_PREFIX_LEN;
 		len += XATTR_MAC_OSX_PREFIX_LEN;
 	}
-- 
1.8.3.1

Re: [PATCH] fs/hfsplus: use memcpy() instead of strncpy()

[Viacheslav Dubeyko]

On Mon, 2018-01-08 at 20:17 +0800, Xiongfeng Wang wrote:
> From: Xiongfeng Wang <xiongfeng.wang@linaro.org>
> 
> gcc-8 reports
> 
> inlined from 'copy_name' at fs/hfsplus/xattr.c:416:3:
> ./include/linux/string.h:245:9: warning: '__builtin_strncpy' output
> truncated before terminating nul copying 4 bytes from a string of the
> same length [-Wstringop-truncation]
> 
> Since we don't need to copy '\0', we can just use memcpy() to avoid
> this
> warning.
> 

If the gcc-8 emits the warning then the suggested change makes sense.
Looks good.

Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>

Thanks,
Vyacheslav Dubeyko.


> Signed-off-by: Xiongfeng Wang <xiongfeng.wang@linaro.org>
> ---
>  fs/hfsplus/xattr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
> index e538b75..0dc8a65 100644
> --- a/fs/hfsplus/xattr.c
> +++ b/fs/hfsplus/xattr.c
> @@ -413,7 +413,7 @@ static int copy_name(char *buffer, const char
> *xattr_name, int name_len)
>  	int offset = 0;
>  
>  	if (!is_known_namespace(xattr_name)) {
> -		strncpy(buffer, XATTR_MAC_OSX_PREFIX,
> XATTR_MAC_OSX_PREFIX_LEN);
> +		memcpy(buffer, XATTR_MAC_OSX_PREFIX,
> XATTR_MAC_OSX_PREFIX_LEN);
>  		offset += XATTR_MAC_OSX_PREFIX_LEN;
>  		len += XATTR_MAC_OSX_PREFIX_LEN;
>  	}