[PATCH 1/4] drivers/net/enic: decrement sizeof size in strncmp

Julia Lawall
2009-11-12T07:48:37Z

From: Julia Lawall <julia@diku.dk>

As observed by Joe Perches, sizeof of a constant string includes the
trailing 0. If what is wanted is to check the initial characters of
another string, this trailing 0 should not be taken into account. If an
exact match is wanted, strcmp should be used instead.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression foo;
constant char *abc;
@@

strncmp(foo, abc,
- sizeof(abc)
+ sizeof(abc)-1
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
drivers/net/enic/vnic_dev.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff -u -p a/drivers/net/enic/vnic_dev.c b/drivers/net/enic/vnic_dev.c
--- a/drivers/net/enic/vnic_dev.c
+++ b/drivers/net/enic/vnic_dev.c
@@ -358,9 +358,9 @@ int vnic_dev_hw_version(struct vnic_dev
if (err)
return err;

- if (strncmp(fw_info->hw_version, "A1", sizeof("A1")) == 0)
+ if (strncmp(fw_info->hw_version, "A1", sizeof("A1") - 1) == 0)
*hw_ver = VNIC_DEV_HW_VER_A1;
- else if (strncmp(fw_info->hw_version, "A2", sizeof("A2")) == 0)
+ else if (strncmp(fw_info->hw_version, "A2", sizeof("A2") - 1) == 0)
*hw_ver = VNIC_DEV_HW_VER_A2;
else
*hw_ver = VNIC_DEV_HW_VER_UNKNOWN;