[U-Boot] [PATCH] pxe: Allow use of environment variables in append string

[Stephen Warren <swarren@wwwdotorg.org>]

On 08/01/2014 03:21 AM, Hans de Goede wrote:
> Use run_command("setenv bootargs <label->append>") so that environment
> variables (e.g. $console) can be used in append strings.

I'm slightly worried that this changes the semantics of the append line 
in the PXE/extlinux config file. Namely, you suddenly have to start 
worrying about escaping any $ signs or semi-colons etc..

> diff --git a/common/cmd_pxe.c b/common/cmd_pxe.c

>   	if (!localcmd)
>   		return -ENOENT;
>
> -	if (label->append)
> -		setenv("bootargs", label->append);
> +	if (label->append) {
> +		bootargs = malloc(strlen("setenv bootargs ") +
> +				  strlen(label->append) + 1);
> +		if (!bootargs)
> +			return 1;

Shouldn't this return a -ve error code for consistency with the other 
pre-existing error case I quoted above.

> +		strcpy(bootargs, "setenv bootargs ");
> +		strcat(bootargs, label->append);
> +		run_command(bootargs, 0);

Using whatever C function that the shell uses to expand variable 
references in the command-line, rather than run_command(), would at 
least avoid the issue of ; in label->append causing part of 
label->append after the ; to be execututed as a separate command.

There would still be the issue of $ suddenly meaning something different.