On Fri, Oct 22, 2021 at 10:29:26AM +0200, Wolfgang Denk wrote: > Dear Simon, > > In message > <20211021210847.v10.3.Ie78bfbfca0d01d9cba501e127f446ec48e1f7afe@changeid> you > 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. > > The README does not contain this information as it has been moved > into doc/usage/environment.rst > > I think the documentation is lacking a hint that multiline > definitions will always be separated by spaces. > > > Also support += to allow variables to be appended to. This is needed when > > using the preprocessor. > > I cannot see what the preprocessor has to do with this feature. It > would be useful in any case, even without the preporcessor. > > > The documentation reads: > > "Variables can contain `+` characters but in the unlikely > event that you want to have a variable name ending in plus, put a backslash > before the `+` so that the script knows you are not adding to an existing > variable but assigning to a new one:: > > maximum\+=value > " > > However, '\' is also a legal character in a variable name (and > doubled backslashes or apostrophes etc. are legal, too), so > above line should actually set the environment variable "maximum\+" > to "value".
I feel I should preface this with "I am cranky". Now I see that I can indeed do: => setenv foo\\bar baz => printenv foo\\bar foo\bar=baz on a system today. To what value, I know not. I can see how you write some fancy state machine set of scripts where you end up with "foo+bar+" needing to be set because you do a bunch of probing of things at run time and concatenate and ... there, we've got a variable that ends in + (and fwiw, sh says baz+ is a bad variable name, bash gets kinda funny with it). I don't see the value in allowing "\" in a variable name, nor can I make bash nor sh handle that. We can just disallow "\" in variable names. -- Tom
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