[BRLTTY] Android: custom data files, BrlAPI and LineageOs

[Dave Mielke]

[quoted lines by Aura Kelloniemi on 2020/05/29 at 09:03 +0300]

>Where (which path, with which permissions, etc.) do I store custom text tables
>and keymaps? 

In the brltty/ folder at the top-level of the external storage device. Since
Android isolates an app (i.e. brltty) to its own user and group, others read
permission would be needed.

That's how it's supposed to work. Looking at that code, it uses a very old
scheme for determining the paths to the external storage devices so it's
possible that the way it does it isn't supported anymore. It's probably time to
retest it.

>And how does BrlAPI work on Android — specifically, how does it
>detect which application should be controlling the display?

It listens on 127.0.0.1:0, i.e. the main BrlAPI port on localhost. A local
(UNIX domain) socket might be better, but I'm not sure that there's a good
place on Android to create one of those (remember that brltty is running as a
regular user without any executable capabilities). The use of a
manifest-specified permission is probably a good idea. Maybe, these days,
there's a way to do that in a way that controls access to a socket.

>Also, has anybody run BRLTTY on LineageOs, and if so, what were the results?

What's that?

>Then I have another question that is related to BrlAPI: would it be possible to
>run in Android a chroot or a container which runs a regular GNU userland with
>BRLTTY (possibly with the "GNU screen" screen driver and with the BrlAPI
>braille driver backed by the BrlAPI server running in Android userspace)?

You'd probably need to do your own Android build for that.

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