termuxlaunchfix

README

Termux Launch Fix

A Go utility that automatically fixes os.Args when running Go applications in Termux on Android. It will also create a start script for the application that uses proot to fix problems with DNS resolution.

os.Args

When running Go applications in Termux on Android os.Args has an additional, preceding argument. os.Args[0] seems to be the path entered by the user and os.Args[1] is the absolute path of the binary one would expect in os.Args[0].

When added as a blank import this utility will automatically strip the first argument from os.Args so your application can keep using it like on any other OS.

DNS Resolution

If your application uses anything that requires DNS lookups it will fail in Termux on Android because Go can't find /etc/resolv.conf and falls back to a local resolver. That, however, doesn't exist, causing all DNS queries to fail.

The fix is to use proot to launch the application with the correct binding for resolv.conf:

proot -b $PREFIX/etc/resolv.conf:/etc/resolv.conf <path to app>

Unfortunately we can't automatically run the application with proot from the Go app. Instead this utility will create a start script in the user's home directory ($HOME/<app name>.proot) that can be used to launch the app through proot. In my use-case this is perfectly fine, but your mileage may vary. Feel free to fork and make your own customizations.

Usage

Just add a blank import to the Go file serving as entry point:

package main

import (
	"fmt"

	_ "github.com/toxyl/termux-launch-fix"  
)

func main() {
	fmt.Println("The blank import is all you need.")
}

Exit Codes

• 100: proot not found - install with pkg install proot
• 101: Problem resolving home directory
• 102: Problem writing start script

Documentation

Index

• Constants

Constants

const (
	EXIT_NO_PROOT             = 100
	EXIT_NO_HOME              = 101
	EXIT_SCRIPT_CREATE_FAILED = 102
)