On Mon, Mar 05, 2018 at 06:19:22PM +0100, Jan Kiszka wrote:
> On 2018-03-05 17:24, [ext] Andreas J. Reichel wrote:
> > From: Andreas Reichel <andreas.reichel....@siemens.com>
> >
> > If 'recovery_status' is set to 'in_progress' by the bootloader interface
> > of SWUpdate, then the api sets the internal environment struct member
> > called 'in_progress' to 1 by creating a new environment. However, if
> > SWUpdate sets it to 'failed', then SWUpdate's bootloader interface calls
> > 'ebg_env_set' with a variable name of 'recovery_status', which creates a
> > user variable with that name.
> > After an update process, the SWUpdate bootloader interface's unset
> > function is called which must unset the 'recovery_status'. However, now
> > depending on wether it was changed to 'in_progress' or 'failed' before,
> > the user variable might exist or not. This logic is complex and much
> > easier to implement into env_api by deleting such a user variable if it
> > exists inside the finalize function.
> >
> > Signed-off-by: Andreas Reichel <andreas.reichel....@siemens.com>
> > ---
> > env/env_api.c | 18 +++++++++++++++---
> > 1 file changed, 15 insertions(+), 3 deletions(-)
> >
> > diff --git a/env/env_api.c b/env/env_api.c
> > index 75695d1..bf5c7c9 100644
> > --- a/env/env_api.c
> > +++ b/env/env_api.c
> > @@ -240,11 +240,23 @@ int ebg_env_close(ebgenv_t *e)
> > return 0;
> > }
> >
> > -int ebg_env_finalize_update(ebgenv_t *e) {
> > +int ebg_env_finalize_update(ebgenv_t *e)
> > +{
> > if (!e->bgenv || !((BGENV *)e->bgenv)->data) {
> > return EIO;
> > }
> > - ((BGENV *)e->bgenv)->data->in_progress = 0;
> > - ((BGENV *)e->bgenv)->data->ustate = USTATE_INSTALLED;
> > +
> > + BG_ENVDATA *data;
> > + data = ((BGENV *)e->bgenv)->data;
> > + data->in_progress = 0;
> > + data->ustate = USTATE_INSTALLED;
> > +
> > + /* Also delete any ramaining user variable called 'recovery_status' */
>
> remaining
>
> Giving a brief reason here again might help event more than describing
> what is done below...
>
> > + uint8_t *recv_status;
> > + recv_status = bgenv_find_uservar(data->userdata, "recovery_status");
> > + if (recv_status) {
> > + bgenv_del_uservar(data->userdata, recv_status);
> > + }
> > +
> > return 0;
> > }
> >
>
> But doesn't that encode the behavior of one user of our API into our
> API? Sounds not like I should like this. Or even merge it.
>
It's true that this is rather SWUpdate specific. I could say that we
have developed the API mainly for SWUpdate but of course that cannot
deny that a generic API should be free of user-specific code that is
not generally applicable.
But what do you think of the following idea:
treat the finalize API call as kind of a destructor for a pre-registered
set of user variables, then the API could provide such a register
function and SWUpdate can - as any software using the API - specify
a list of user variables that must be garbage collected (deleted) upon
call of ebg_env_finalize_update. This way we
* don't have SWUpdate specific code in here
* specify a method that SWUpdate can use to solve its problem
* provide a user-friendly method to clean up user variable space
with temporal variables needed only by the update process
Andreas
> Jan
>
> --
> Siemens AG, Corporate Technology, CT RDA IOT SES-DE
> Corporate Competence Center Embedded Linux
--
Andreas Reichel
Dipl.-Phys. (Univ.)
Software Consultant
andreas.reic...@tngtech.com, +49-174-3180074
TNG Technology Consulting GmbH, Betastr. 13a, 85774 Unterfoehring
Geschaeftsfuehrer: Henrik Klagges, Dr. Robert Dahlke, Gerhard Mueller
Sitz: Unterfoehring * Amtsgericht Muenchen * HRB 135082
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