[PATCH] tools: mkenvimage: Add pure shell implementation of mkenvimage

[Rasmus Villemoes]

On Wed, Feb 05 2025, Marek Vasut <marex at denx.de> wrote:

> Add implementation of mkenvimage written purely in bourne shell.
>
> This is not a replacement for mkenvimage tool, but rather a simple
> implementation which can be used in environments where mkenvimage
> itself cannot be deployed due to various constraints, like hardware
> manufacturing plants, but where bourne shell and basic tool are
> already available.
>
> The external dependencies which are not shell built-ins are gzip
> and grep.
>

Eh, and cat, sort, dd, tr, mktemp, head, tail, mv and rm ?

> All mkenvimage parameters are implemented and compatible with the
> C implementation of mkenvimage.
>
> Signed-off-by: Marek Vasut <marex at denx.de>
> ---
> Cc: Joe Hershberger <joe.hershberger at ni.com>
> Cc: Tom Rini <trini at konsulko.com>
> ---
>  tools/mkenvimage.sh | 126 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 126 insertions(+)
>  create mode 100755 tools/mkenvimage.sh
>
> diff --git a/tools/mkenvimage.sh b/tools/mkenvimage.sh
> new file mode 100755
> index 00000000000..f83fac92e5d
> --- /dev/null
> +++ b/tools/mkenvimage.sh
> @@ -0,0 +1,126 @@
> +#!/bin/sh
> +
> +print_help() {
> +	echo "mkenvimage [-h] [-V] [-r] [-b] [-p <byte>] -s <environment partition size> -o <output> <input file>"

Nit: you included a .sh extension in the filename, probably this output
should reflect that.

> +
> +(
> +# Read input environment file, make sure there is a trailing newline,
> +# sort the result and remove empty and commented out lines.
> +( cat "${INFILE}" ; echo ) | sort -u "${INFILE}" | grep -v '^#' | grep -v '^[ \t]*$' | tr '\n' '\0'

Doesn't sort ignore stdin when given file(s) via argv? Also, the newline
added by that echo would probably by removed by the grep, and you
manually insert a \0 right after, so probably the first cat;echo should
just be removed.

I'm also wondering why you even do that sort; AFAIK, mkenvimage doesn't
do that. And it would make a difference if the input fx had two
definitions for the same variable

foo=Y
foo=X

because when loaded on target, the last occurring value takes
precedence.

Are you handling escaping of newlines, in order to allow values to
contain newline characters?

Rasmus