[Arm-netbook] Side-Topic: Liberating PocketCHIP

[Benson Mitchell]

On May 9, 2017 7:02 PM, "John Luke Gibson" <eaterjolly at gmail.com> wrote:

Like, the first file initiated by the main make file is
support/setlocalversion which looks to just check a whole bunch of
un-special variables which weren't set in the make script and had no
opportunity to be set by any other files I know of (on my system the
variables show as empty not having run anything from buildroot, but I
can't imagine head would be set to such a specific git command on
accident as the one it checks for). Then the if one of the conditions
were some how filled, then all it does is print weird strings like
this:

printf '%s%s' -g $head

Like this is the if statement:

if head=`git rev-parse --verify --short HEAD 2>/dev/null`

That "=" is assignment, and those "`"s are output substitution. It tries
executing that git command, storing the output in the shell variable head.
If git succeeds (returns zero), the then clause is executed; if git fails
(returns non-zero), the else clause (if present) is executed.

Mind you all this is printed to a variable in the make script called
BR2_Version_Full which does nothing in the make script but get printed
if a person asks the version, the script calls target-finalize or
legal-info-prepare (which it looks like it does unconditionally in
both cases). Like am I really that deep in over my head

Apparently, but that's how we learn, right? :)

or does this
script really have a bug where if someone sets head to some weird
obscure git command it prints that very command in it's legal info?

No.

Like how does that happen that way on accident? It looks like it might
serve some obscure purpose if it ran the command (which from I can
tell with bash, setting some $(shell x) might do that,

"$(foo)" and "`foo`" are essentially the same. They both run foo, and
substitute the output.
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