[U-Boot] [PATCH] cmd: nvedit: env_get_f must check for env_get_char error codes

[York Sun <york.sun@nxp.com>]

On 01/30/2018 10:57 PM, Simon Goldschmidt wrote:
> env_get_f calls env_get_char to load single characters from the
> environment. However, the return value of env_get_char was not
> checked for errors. Now if the env driver does not support the
> .get_char call, env_get_f did not notice this and looped over the
> whole size of the environment, calling env_get_char over 8000
> times with the default settings, just to return an error in the
> end.
> 
> Fix this by checking if env_get_char returns < 0.
> 
> Signed-off-by: Simon Goldschmidt <sgoldschmidt@de.pepperl-fuchs.com>
> ---
> 
>  cmd/nvedit.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/cmd/nvedit.c b/cmd/nvedit.c
> index a690d743cd..4cb25b8248 100644
> --- a/cmd/nvedit.c
> +++ b/cmd/nvedit.c
> @@ -650,12 +650,14 @@ char *env_get(const char *name)
>   */
>  int env_get_f(const char *name, char *buf, unsigned len)
>  {
> -	int i, nxt;
> +	int i, nxt, c;
>  
>  	for (i = 0; env_get_char(i) != '\0'; i = nxt + 1) {
>  		int val, n;
>  
> -		for (nxt = i; env_get_char(nxt) != '\0'; ++nxt) {
> +		for (nxt = i; (c = env_get_char(nxt)) != '\0'; ++nxt) {
> +			if (c < 0)
> +				return c;
>  			if (nxt >= CONFIG_ENV_SIZE)
>  				return -1;
>  		}
> @@ -666,7 +668,10 @@ int env_get_f(const char *name, char *buf, unsigned len)
>  
>  		/* found; copy out */
>  		for (n = 0; n < len; ++n, ++buf) {
> -			*buf = env_get_char(val++);
> +			c = env_get_char(val++);
> +			if (c < 0)
> +				return c;
> +			*buf = c;
>  			if (*buf == '\0')
>  				return n;
>  		}
> 

Simon,

This patch looks correct. But it doesn't fix NOR flash. Do you have plan
to add .get_char function to other drivers? Without that function, we
cannot get env variables before relocation.

York