Mimicking Termux Behavior

[mcondarelli]

I have a rather strange request, please tell me if what I'm trying to do is possible and even makes sense.

I need to integrate in a normal Android 12 / Kotlin app some pre-existing, large Node.Js code (possibly without rewriting it in a different language, of course).

Said code seems to work as expected under Termux.
I would like to do without the quite large Termux infrastructure, though.

I was able to extract relevant parts of Termux installation (Node.Js interpreter, a few .so and required Javascript code) and have as a subprocess of my app.

Problem is I seem able to do this only if I disable SELinux (su setenforce 0), otherwise execution is prevented (permission error).

Termux is obviously able to run random executables without requiring this.
What am I missing?
I sincerely hope I'm just missing some stupid setup/permission request and knowledgeable guys can point me in the right direction.

If this is not the case please point me to reasons why I'm trying to do something (nearly) impossible.

To clarify my position:

• I need to port a large Linux program to Android.
• this program will be installed on certain, well-defined, devices in factory.
• this program is not supposed to work anywhere else and will not be available on AppStore.
• I have access to Manufacturer so I could ask for signing of my APP or whatever (within reason).
• Device has a fairly standard Android 12 and I'm not interested to run this anywhere else.
• Device OS won't be updated in the foreseeable future.
• I would like to avoid the overhead of a full Termux installation, if possible.

Many THANKS in Advance

[twaik]

Termux is obviously able to run random executables without requiring this.

Termux can run random executables because of targetSdkVersion=28. If you set higher targetSdkVersion android will block execution of W^X executables.
But if you are planning to use executables on sdcard you can simply build your nodejs version with -Wl,-rpath=$ORIGIN in LDFLAGS and put the main nodejs executable (renamed to libnodejs.so) and all libraries into lib/<abi> of your apk, allowing it to be executed as regular code after extracting.

[agnostic-apollo]

Restrictions regarding android file executions are detailed at https://github.com/agnostic-apollo/Android-Docs/blob/master/site/pages/en/projects/docs/apps/processes/app-data-file-execute-restrictions.md but they are not relevant if you use targetSdkVersion = 28 for your app. A higher version would require the APK Native Library or System Linker Exec, and would be necessary if your app will be installed as a system app.

Additionally, you cannot use binaries/libraries compiled for com.termux package in your own app. You would need to compile the bootstrap and all additional packages for your own app package name. And without an apt repo, you will not be able to update the packages from the device, unless the APK update comes with a new bootstrap that overwrites the old prefix installation.

• https://github.com/termux/termux-packages/wiki/For-maintainers#bootstraps
• Infra, Build Order and Build Bootstraps Improvements termux-packages#24647
• https://github.com/termux/termux-packages/wiki/Build-environment
• https://github.com/termux/termux-packages/wiki/Building-packages