[U-Boot] [PATCH 02/17] fs: fat: handle "." and ".." of root dir correctly with fat_itr_resolve()

[Heinrich Schuchardt]

On 07/20/2018 04:57 AM, AKASHI Takahiro wrote:
> FAT's root directory does not have "." nor ".."
> So care must be taken when scanning root directory with fat_itr_resolve().
> Without this patch, any file path starting with "." or ".." will not be
> resolved at all.
> 
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---
>  fs/fat/fat.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/fs/fat/fat.c b/fs/fat/fat.c
> index b48f48a751..fd6523c66b 100644
> --- a/fs/fat/fat.c
> +++ b/fs/fat/fat.c
> @@ -927,6 +927,27 @@ static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
>  	while (next[0] && !ISDIRDELIM(next[0]))
>  		next++;
>  
> +	if (itr->is_root) {
> +		/* root dir doesn't have "." nor ".." */

I understand why root has no ../ but  /./ should be valid.

On Linux 'ls /./' displays the root directory.

Best regards

Heinrich

> +		if ((((next - path) == 1) && !strncmp(path, ".", 1)) ||
> +		    (((next - path) == 2) && !strncmp(path, "..", 2))) {
> +			/* point back to itself */
> +			itr->clust = itr->fsdata->root_cluster;
> +			itr->dent = NULL;
> +			itr->remaining = 0;
> +			itr->last_cluster = 0;
> +
> +			if (next[0] == 0) {
> +				if (type & TYPE_DIR)
> +					return 0;
> +				else
> +					return -ENOENT;
> +			}
> +
> +			return fat_itr_resolve(itr, next, type);
> +		}
> +	}
> +
>  	while (fat_itr_next(itr)) {
>  		int match = 0;
>  		unsigned n = max(strlen(itr->name), (size_t)(next - path));
>