From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Barebox List <barebox@lists.infradead.org>
Subject: Re: [PATCH] ubiformat: improve generation of UBI image sequence
Date: Tue, 16 Jul 2019 10:09:11 +0200 [thread overview]
Message-ID: <20190716080911.p53fxgo3m5h3plmd@pengutronix.de> (raw)
In-Reply-To: <20190715090900.19123-1-s.hauer@pengutronix.de>
On Mon, Jul 15, 2019 at 11:09:00AM +0200, Sascha Hauer wrote:
> The UBI ec_hdr has an image_seq field. During attaching UBI expects
> that its value is the same for all eraseblocks. The value should be
> changed with every ubiformat and is used to detect half written images.
>
> In barebox we use a pseudo random number generated with rand() for this
> value. The ubiformat command calls srand(get_time_ns()) to initialize
> the pseudo random numbber generator. This is done in the option parser,
s/bb/b/
> so when ubiformat() is called directly (from fastboot for example) the
> pseudo random number generator is not initialized and we get the same
> values after every barebox restart.
I don't understand the problem (i.e. where is srand() called up to now),
but that's not important. I wonder if you could just use some data from
the NAND to (additionally) initialize the rng?
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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prev parent reply other threads:[~2019-07-16 8:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 9:09 Sascha Hauer
2019-07-16 8:09 ` Uwe Kleine-König [this message]
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