Re: [PATCH 3/3] libmount/utils: Use binary search to compare pseudofs

[Davidlohr Bueso <dave@gnu.org>]

On Sat, 2012-05-19 at 20:39 -0400, Dave Reisner wrote:
> While we're at it, expand this list of known pseudofs types.
> 
> Signed-off-by: Dave Reisner <dreisner@archlinux.org>
> ---
>  libmount/src/utils.c |   68 +++++++++++++++++++++++++++++++-------------------
>  1 file changed, 43 insertions(+), 25 deletions(-)
> 
> diff --git a/libmount/src/utils.c b/libmount/src/utils.c
> index b824edc..77557f2 100644
> --- a/libmount/src/utils.c
> +++ b/libmount/src/utils.c
> @@ -72,6 +72,15 @@ int mnt_parse_offset(const char *str, size_t len, uintmax_t *res)
>  	return rc;
>  }
>  
> +/* used as a callback by bsearch in mnt_fstype_is_pseudofs() */
> +static int fstype_cmp(const void *v1, const void *v2)
> +{
> +	const char *s1 = *(const char **)v1;
> +	const char *s2 = *(const char **)v2;
> +
> +	return strcmp(s1, s2);
> +}
> +
>  /* returns basename and keeps dirname in the @path, if @path is "/" (root)
>   * then returns empty string */
>  static char *stripoff_last_component(char *path)
> @@ -214,31 +223,40 @@ char *mnt_unmangle(const char *str)
>   */
>  int mnt_fstype_is_pseudofs(const char *type)
>  {
> -	if (!type)
> -		return 0;
> -	if (strcmp(type, "none")  == 0 ||
> -	    strcmp(type, "proc")  == 0 ||
> -	    strcmp(type, "tmpfs") == 0 ||
> -	    strcmp(type, "sysfs") == 0 ||
> -	    strcmp(type, "autofs") == 0 ||
> -	    strcmp(type, "devpts") == 0||
> -	    strcmp(type, "cgroup") == 0 ||
> -	    strcmp(type, "devtmpfs") == 0 ||
> -	    strcmp(type, "devfs") == 0 ||
> -	    strcmp(type, "dlmfs") == 0 ||
> -	    strcmp(type, "cpuset") == 0 ||
> -	    strcmp(type, "configfs") == 0 ||
> -	    strcmp(type, "securityfs") == 0 ||
> -	    strcmp(type, "hugetlbfs") == 0 ||
> -	    strcmp(type, "rpc_pipefs") == 0 ||
> -	    strcmp(type, "fusectl") == 0 ||
> -	    strcmp(type, "mqueue") == 0 ||
> -	    strcmp(type, "binfmt_misc") == 0 ||
> -	    strcmp(type, "fuse.gvfs-fuse-daemon") == 0 ||
> -	    strcmp(type, "debugfs") == 0 ||
> -	    strcmp(type, "spufs") == 0)
> -		return 1;
> -	return 0;
> +	static const char *pseudofs[] = {
> +		"anon_inodefs",
> +		"autofs",
> +		"bdev",
> +		"binfmt_misc",
> +		"cgroup",
> +		"configfs",
> +		"cpuset",
> +		"debugfs",
> +		"devfs",
> +		"devpts",
> +		"devtmpfs",
> +		"dlmfs",
> +		"fuse.gvfs-fuse-daemon",
> +		"fusectl",
> +		"hugetlbfs",
> +		"mqueue",
> +		"nfsd",
> +		"none",
> +		"pipefs",
> +		"proc",
> +		"pstore",
> +		"ramfs",
> +		"rootfs",
> +		"rpc_pipefs",
> +		"securityfs",
> +		"sockfs",
> +		"spufs",
> +		"sysfs",
> +		"tmpfs"
> +	};
> +

What about applying sort (qsort(3)) before searching here? This would
correct any manual string sorting that pseudofs[] imposes to the
developer.

> +	return !(bsearch(&type, pseudofs, ARRAY_SIZE(pseudofs),
> +				sizeof(char*), fstype_cmp) == NULL);
>  }
>  
>  /**