[PATCH] fastboot: inform user if barebox update falls back to raw copy

[Sascha Hauer]

On Tue, May 31, 2022 at 11:35:37AM +0200, Ahmad Fatoum wrote:
> Fastboot code determines whether to go into barebox update handler by
> checking whether filetype_is_barebox_image() returns true for the image.
> This is different from the barebox_update command which leaves it to the
> individual handlers to decide whether an image is suitable.
> 
> Coupled with eMMC boot partitions, this could lead to
> `barebox_update -t mmc` updating the boot partition, while a
> `fastboot flash bbu-mmc` will write the image to the user area instead.
> 
> It may be worth breaking backwards compatibility here and refuse update
> in that case, but for now at least alert the user that a raw copy is
> being attempted.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
>  common/fastboot.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/common/fastboot.c b/common/fastboot.c
> index f8ed40c86e00..50ea8421d92c 100644
> --- a/common/fastboot.c
> +++ b/common/fastboot.c
> @@ -673,7 +673,7 @@ static void cb_flash(struct fastboot *fb, const char *cmd)
>  		goto out;
>  	}
>  
> -	if (IS_ENABLED(CONFIG_BAREBOX_UPDATE) && filetype_is_barebox_image(filetype)) {
> +	if (IS_ENABLED(CONFIG_BAREBOX_UPDATE)) {


>  		void *buf;
>  		struct bbu_handler *handler;
>  		struct bbu_data data = {
> @@ -681,6 +681,17 @@ static void cb_flash(struct fastboot *fb, const char *cmd)
>  			.flags = BBU_FLAG_YES,
>  		};
>  
> +		if (!filetype_is_barebox_image(filetype)) {
> +			if (strstarts(fentry->name, "bbu-")) {
> +				fastboot_tx_print(fb, FASTBOOT_MSG_INFO,
> +						  "This is _not_ a barebox image...");
> +				fastboot_tx_print(fb, FASTBOOT_MSG_INFO,
> +						  "Falling back to raw copy to %s", filename);
> +			}
> +
> +			goto copy;
> +		}

The handlers starting with "bbu-" are registered from the barebox update
code, so falling back to copy is clearly wrong.

The logic to enter this barebox_update path should be:

	if (IS_ENABLED(CONFIG_BAREBOX_UPDATE) &&
	    (filetype_is_barebox_image(filetype) || strstarts(fentry->name, "bbu-")))

That way we are sure that barebox_update is called when we need it. Also
behaviour is consistent to what barebox_update does on the command line.

Sascha

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