From: Julia Lawall <julia@diku.dk>
To: al@alarsen.net, linux-kernel@vger.kernel.org,
kernel-janitors@vger.kernel.org
Subject: [PATCH 4/4] fs/qnx4: decrement sizeof size in strncmp
Date: Thu, 12 Nov 2009 08:49:44 +0100 (CET) [thread overview]
Message-ID: <Pine.LNX.4.64.0911120849260.16627@ask.diku.dk> (raw)
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>
---
fs/qnx4/inode.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/fs/qnx4/inode.c b/fs/qnx4/inode.c
index 449f5a6..0614b00 100644
--- a/fs/qnx4/inode.c
+++ b/fs/qnx4/inode.c
@@ -221,7 +221,9 @@ static const char *qnx4_checkroot(struct super_block *sb)
rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);
if (rootdir->di_fname != NULL) {
QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
- if (!strncmp(rootdir->di_fname, QNX4_BMNAME, sizeof QNX4_BMNAME)) {
+ if (!strncmp(rootdir->di_fname,
+ QNX4_BMNAME,
+ sizeof QNX4_BMNAME - 1)) {
found = 1;
qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
if (!qnx4_sb(sb)->BitMap) {
next reply other threads:[~2009-11-12 7:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-12 7:49 Julia Lawall [this message]
2009-11-12 9:25 ` Anders Larsen
2009-11-12 10:05 ` Julia Lawall
2009-11-12 10:14 ` Julia Lawall
2009-11-12 10:22 ` sizeof vs strlen (was Re: [PATCH 4/4] fs/qnx4: decrement sizeof size in strncmp) Bernd Petrovitsch
2009-11-12 10:37 ` Julia Lawall
2009-11-12 15:33 ` Julia Lawall
2009-11-13 16:42 ` Bernd Petrovitsch
2009-11-12 23:49 ` [PATCH 4/4] fs/qnx4: decrement sizeof size in strncmp David Wagner
2009-11-13 0:06 ` Joe Perches
2009-11-12 22:08 Anders Larsen
2009-12-18 14:26 ` Jiri Kosina
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