[PATCH] fs: Prefer strlcpy() over snprintf()

[PATCH] fs: Prefer strlcpy() over snprintf()

[Jean Delvare]

strlcpy is faster than snprintf when you don't use the returned value.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Andries Brouwer <aeb@cwi.nl>
---
A quick grep suggests that there's about 80 more similar cases in the kernel
tree which could be fixed.

 fs/configfs/dir.c     |    2 +-
 fs/gfs2/ops_fstype.c  |    4 ++--
 fs/partitions/check.c |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

--- linux-2.6.26-rc1.orig/fs/configfs/dir.c	2008-05-09 12:52:51.000000000 +0200
+++ linux-2.6.26-rc1/fs/configfs/dir.c	2008-05-09 13:20:24.000000000 +0200
@@ -1041,7 +1041,7 @@ static int configfs_mkdir(struct inode *
 		goto out_put;
 	}
 
-	snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
+	strlcpy(name, dentry->d_name.name, dentry->d_name.len + 1);
 
 	mutex_lock(&subsys->su_mutex);
 	group = NULL;
--- linux-2.6.26-rc1.orig/fs/gfs2/ops_fstype.c	2008-05-09 12:52:51.000000000 +0200
+++ linux-2.6.26-rc1/fs/gfs2/ops_fstype.c	2008-05-09 13:20:24.000000000 +0200
@@ -142,8 +142,8 @@ static int init_names(struct gfs2_sbd *s
 	if (!table[0])
 		table = sdp->sd_vfs->s_id;
 
-	snprintf(sdp->sd_proto_name, GFS2_FSNAME_LEN, "%s", proto);
-	snprintf(sdp->sd_table_name, GFS2_FSNAME_LEN, "%s", table);
+	strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
+	strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
 
 	table = sdp->sd_table_name;
 	while ((table = strchr(table, '/')))
--- linux-2.6.26-rc1.orig/fs/partitions/check.c	2008-05-09 12:52:51.000000000 +0200
+++ linux-2.6.26-rc1/fs/partitions/check.c	2008-05-09 13:20:24.000000000 +0200
@@ -123,7 +123,7 @@ static int (*check_part[])(struct parsed
 char *disk_name(struct gendisk *hd, int part, char *buf)
 {
 	if (!part)
-		snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
+		strlcpy(buf, hd->disk_name, BDEVNAME_SIZE);
 	else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
 		snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, part);
 	else


-- 
Jean Delvare

Re: [PATCH] fs: Prefer strlcpy() over snprintf()

[Steven Whitehouse]

Hi,

The patch looks good, but could you break this into bits? Its easier for
me just to put the GFS2 bit through my git tree and the other bits
should probably go via another route,

Steve.

On Fri, 2008-05-09 at 13:42 +0200, Jean Delvare wrote:
> strlcpy is faster than snprintf when you don't use the returned value.
> 
> Signed-off-by: Jean Delvare <khali@linux-fr.org>
> Cc: Joel Becker <joel.becker@oracle.com>
> Cc: Steven Whitehouse <swhiteho@redhat.com>
> Cc: Andries Brouwer <aeb@cwi.nl>
> ---
> A quick grep suggests that there's about 80 more similar cases in the kernel
> tree which could be fixed.
> 
>  fs/configfs/dir.c     |    2 +-
>  fs/gfs2/ops_fstype.c  |    4 ++--
>  fs/partitions/check.c |    2 +-
>  3 files changed, 4 insertions(+), 4 deletions(-)
> 
> --- linux-2.6.26-rc1.orig/fs/configfs/dir.c	2008-05-09 12:52:51.000000000 +0200
> +++ linux-2.6.26-rc1/fs/configfs/dir.c	2008-05-09 13:20:24.000000000 +0200
> @@ -1041,7 +1041,7 @@ static int configfs_mkdir(struct inode *
>  		goto out_put;
>  	}
>  
> -	snprintf(name, dentry->d_name.len + 1, "%s", dentry->d_name.name);
> +	strlcpy(name, dentry->d_name.name, dentry->d_name.len + 1);
>  
>  	mutex_lock(&subsys->su_mutex);
>  	group = NULL;
> --- linux-2.6.26-rc1.orig/fs/gfs2/ops_fstype.c	2008-05-09 12:52:51.000000000 +0200
> +++ linux-2.6.26-rc1/fs/gfs2/ops_fstype.c	2008-05-09 13:20:24.000000000 +0200
> @@ -142,8 +142,8 @@ static int init_names(struct gfs2_sbd *s
>  	if (!table[0])
>  		table = sdp->sd_vfs->s_id;
>  
> -	snprintf(sdp->sd_proto_name, GFS2_FSNAME_LEN, "%s", proto);
> -	snprintf(sdp->sd_table_name, GFS2_FSNAME_LEN, "%s", table);
> +	strlcpy(sdp->sd_proto_name, proto, GFS2_FSNAME_LEN);
> +	strlcpy(sdp->sd_table_name, table, GFS2_FSNAME_LEN);
>  
>  	table = sdp->sd_table_name;
>  	while ((table = strchr(table, '/')))
> --- linux-2.6.26-rc1.orig/fs/partitions/check.c	2008-05-09 12:52:51.000000000 +0200
> +++ linux-2.6.26-rc1/fs/partitions/check.c	2008-05-09 13:20:24.000000000 +0200
> @@ -123,7 +123,7 @@ static int (*check_part[])(struct parsed
>  char *disk_name(struct gendisk *hd, int part, char *buf)
>  {
>  	if (!part)
> -		snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
> +		strlcpy(buf, hd->disk_name, BDEVNAME_SIZE);
>  	else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
>  		snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, part);
>  	else
> 
> 

Re: [PATCH] fs: Prefer strlcpy() over snprintf()

[Jean Delvare]

Hi Steven,

On Fri, 09 May 2008 13:15:54 +0100, Steven Whitehouse wrote:
> The patch looks good, but could you break this into bits? Its easier for
> me just to put the GFS2 bit through my git tree and the other bits
> should probably go via another route,

Thanks for the review. No problem, I'll split the patch and send the
individual bits to their respective maintainers now.

-- 
Jean Delvare