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

[Sascha Hauer <sha@pengutronix.de>]

On Thu, Jun 09, 2022 at 10:21:46AM +0200, Ahmad Fatoum wrote:
> Hello Sascha,
> 
> On 09.06.22 09:19, Sascha Hauer wrote:
> > 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@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.
> 
> This is not consistent with barebox_update behavior. Calling it from command line
> will leave it to update handlers to determine whether an image is a barebox
> image. filetype_is_barebox_image() is exclusively used for fastboot.

With my suggestion we also leave it to the update handlers to decide
whether an image is suitable or not.

Sascha

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