On Tue, Oct 19, 2021 at 08:11:08AM -0600, Simon Glass wrote:
Hi Tom,
On Tue, 19 Oct 2021 at 08:07, Tom Rini trini@konsulko.com wrote:
On Mon, Oct 18, 2021 at 12:13:18PM -0600, Simon Glass wrote:
At present U-Boot environment variables, and thus scripts, are defined by CONFIG_EXTRA_ENV_SETTINGS. It is painful to add large amounts of text to this file and dealing with quoting and newlines is harder than it should be. It would be better if we could just type the script into a text file and have it included by U-Boot.
Add a feature that brings in a .env file associated with the board config, if present. To use it, create a file in a board/<vendor> directory, typically called <board>.env and controlled by the CONFIG_ENV_SOURCE_FILE option.
The environment variables should be of the form "var=value". Values can extend to multiple lines. See the README under 'Environment Variables:' for more information and an example. Note that environment variables may not end in + but can start with other strange characters, including underscore, comma and slash.
In many cases environment variables need access to the U-Boot CONFIG variables to select different options. Enable this so that the environment scripts can be as useful as the ones currently in the board config files. This uses the C preprocessor, means that comments can be included in the environment using /* ... */
Also support += to allow variables to be appended to. This is needed when using the preprocessor.
Signed-off-by: Simon Glass sjg@chromium.org
As much as I and others appreciate that you've written the parser here in a classic UNIX tool, awk, since a lot of the problems also seem to stem from having the parser be able to handle previously valid environment variables, if this was written in Python say, would we have this problem?
Well ideally I'd like to avoid Python in this case as it is in the compilation path. I am not sure yet what Wolfgang actually wants, apart from variable names ending with + which I would like to disallow.
So if we can clearly understand the goal, then we might be able to do it in awk, but, again, can we just disallow '+' in var names ?
If we say that everything that's valid in the environment today needs to continue to be valid, so that includes '+' and only disallowing '=' and NUL as Wolfgang has said, can you update the awk parser to handle it?