[U-Boot] [PATCH] common: nvedit to protect additional ethernet addresses Part 1/1

[Wolfgang Denk]

Dear Stefan Althoefer,

In message <ghgj6n$sen$1 at ger.gmane.org> you wrote:
> From fdeee62f0902b25be1a2a6bf52fb714b0f4f9e59 Mon Sep 17 00:00:00 2001
> From: Stefan Althoefer <stefan.althoefer at web.de>
> Date: Sun, 7 Dec 2008 14:17:08 +0100
> Subject: [PATCH] common: nvedit to protect additional ethernet addresses
> 
> This adds "eth[0-9]+addr" to the protected
> environment variables that can only be written once.
> 
> Code for detecting protected variables was restructured.
> 
> Signed-off-by: Stefan Althoefer <stefan.althoefer at web.de>
...
> @@ -181,18 +186,31 @@ int _do_setenv (int flag, int argc, char *argv[])
>  		 * Ethernet Address and serial# can be set only once,
>  		 * ver is readonly.
>  		 */
> -		if (
> +		protected = 0;
>  #ifdef CONFIG_HAS_UID
>  		/* Allow serial# forced overwrite with 0xdeaf4add flag */
> -		    ((strcmp (name, "serial#") == 0) && (flag != 0xdeaf4add)) ||
> +		if ((strcmp (name, "serial#") == 0) && (flag != 0xdeaf4add))
>  #else
> -		    (strcmp (name, "serial#") == 0) ||
> +		if (strcmp (name, "serial#") == 0)
>  #endif
> -		    ((strcmp (name, "ethaddr") == 0)
> +			protected = 1;

Here we already know that the variable is "serial#", so it cannot be
any of the "eth*addr" variables.

> +		if (strcmp (name, "ethaddr") == 0)
>  #if defined(CONFIG_OVERWRITE_ETHADDR_ONCE) && defined(CONFIG_ETHADDR)
> -		     && (strcmp ((char *)env_get_addr(oldval),MK_STR(CONFIG_ETHADDR)) != 0)
> +			/* Allow "ethaddr" overwrite to change pre-configured address */
> +			if (strcmp ((char *)env_get_addr(oldval),MK_STR(CONFIG_ETHADDR)) != 0)
>  #endif	/* CONFIG_OVERWRITE_ETHADDR_ONCE && CONFIG_ETHADDR */
> -		    ) ) {
> +				protected = 1;
> +
> +		/* "eth[0-9]+addr" is always protected */
> +		if (strncmp (name, "eth", 3) == 0) {
> +			ethnum = simple_strtoul (name+3, &s, 10);
> +			if (s != name + 3)
> +				if (strcmp (s, "addr") == 0)
> +					protected = 1;
> +		}

Then why do we continue to test for these impossible cases? It's just
wasting CPU cycles.

Best regards,

Wolfgang Denk

-- 
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