Re: [PATCH v2 09/25] Use asprintf() for fuse_mnt_build_{source,type}

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Mar 26, 2026 at 10:34:42PM +0100, Bernd Schubert wrote:
> Simplify the code by using asprintf.
> 
> Suggested-by: "Darrick J. Wong" <djwong@kernel.org>
> Signed-off-by: Bernd Schubert <bschubert@ddn.com>
> ---
>  lib/mount.c | 28 +++++++++++++---------------
>  1 file changed, 13 insertions(+), 15 deletions(-)
> 
> diff --git a/lib/mount.c b/lib/mount.c
> index fe353e2cc4579adb47473cac5db7d1bae2defb2c..68f9219d2b8beee51346b198ce826138b9528e73 100644
> --- a/lib/mount.c
> +++ b/lib/mount.c
> @@ -754,32 +754,30 @@ char *fuse_mnt_build_source(const struct mount_opts *mo)
>  {
>  	const char *devname = fuse_mnt_get_devname();
>  	char *source;
> +	int ret;
>  
> -	source = malloc((mo->fsname ? strlen(mo->fsname) : 0) +
> -			(mo->subtype ? strlen(mo->subtype) : 0) +
> -			strlen(devname) + 32);
> -	if (!source)
> +	ret = asprintf(&source, "%s",
> +		       mo->fsname ? mo->fsname :
> +				    (mo->subtype ? mo->subtype : devname));

That works, though I had been expecting something more like:

	if (mo->fsname)
		ret = asprintf(&source, "%s", mo->fsname);
	else if (mo->subtype)
		ret = asprintf(&source, "%s", mo->subtype);
	else
		ret = asprintf(&source, "%s", devname);
	return ret ? NULL : source;

Eh whatever :)
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> +	if (ret == -1)
>  		return NULL;
>  
> -	strcpy(source,
> -	       mo->fsname ? mo->fsname : (mo->subtype ? mo->subtype : devname));
> -
>  	return source;
>  }
>  
>  char *fuse_mnt_build_type(const struct mount_opts *mo)
>  {
>  	char *type;
> +	int ret;
>  
> -	type = malloc((mo->subtype ? strlen(mo->subtype) : 0) + 32);
> -	if (!type)
> +	if (mo->subtype)
> +		ret = asprintf(&type, "%s.%s", mo->blkdev ? "fuseblk" : "fuse",
> +			       mo->subtype);
> +	else
> +		ret = asprintf(&type, "%s", mo->blkdev ? "fuseblk" : "fuse");
> +
> +	if (ret == -1)
>  		return NULL;
>  
> -	strcpy(type, mo->blkdev ? "fuseblk" : "fuse");
> -	if (mo->subtype) {
> -		strcat(type, ".");
> -		strcat(type, mo->subtype);
> -	}
> -
>  	return type;
>  }
> 
> -- 
> 2.43.0
> 
>