Re: Android port of Emacs

[Po Lu]

Gregory Heytings <gregory@heytings.org> writes:

> IOW, users will run Termux under Emacs instead of running Emacs under
> Termux.  (Yes, that's a simplified way of presenting things, but it's
> the idea.)

Termux (the terminal emulator) is not Termux, the package archive.

> Concretely speaking, this means that the same programs will be
> installed twice on the same device (which typically do not have a
> large storage capacity): in the /data/data/com.termux directory, and
> in the /data/data/org.gnu.emacs directory.
>
> Concretely speaking, this also means that all programs installed in
> the /data/data/org.gnu.emacs directory need to be built from source,
> either on the Android device itself (but they typically have slow
> CPUs) or by cross-compiling them on a faster computer.

The termux-packages repository provides several scripts which make this
process trivial.  The result is a `bootstrap-aarch64.zip' that only
needs to be extracted within Emacs.

> I've also looked at the "exec" subdirectory in the feature branch.
> You may be aware that the hack you use there to circumvent Android's
> "write xor execute" security policy has been rejected by the Termux
> developers, and that in all likelihood that hole in Android's security
> policy will be patched sooner or later.

Using a userspace ELF loader cannot be ``patched'' by Android security
policy as long as Android continues to allow ordinary user processes to
trace their children, and thus read and write process memory and
registers.

If you want to argue over this, I ask you to first describe in detail
the procedure used to execute binaries, and then how you propose to
prevent it from being used, while keeping the ability to debug programs.

Which, btw, is a solution Termux will have to adopt at some point,
because in the future, Android will no longer allow applications
targeting API level 29 to be installed.