Distribute Magisk directly with Magisk Manager APK. The APK will
contain all required binaries and scripts for installation and
uninstallation. App versions will now align with Magisk releases.
Extra effort is spent to make the APK itself also a flashable zip that
can be used in custom recoveries, so those still prefer to install
Magisk with recoveries will not be affected with this change.
As a bonus, this makes the whole installation and uninstallation
process 100% offline. The existing Magisk Manager was not really
functional without an Internet connection, as the installation process
was highly tied to zips hosted on the server.
An additional bonus: since all binaries are now shipped as "native
libraries" of the APK, we can finally bump the target SDK version
higher than 28. The target SDK version was stuck at 28 for a long time
because newer SELinux restricts running executables from internal
storage. More details can be found here: https://github.com/termux/termux-app/issues/1072
The target SDK bump will be addressed in a future commit.
Co-authored with @vvb2060
Magisk's policy is to never allow 3rd party code to be loaded in the
zygote daemon process so we have 100% control over injection and hiding.
However, this makes it impossible for 3rd party modules to run anything
before process specialization, which includes the ability to modify the
arguments being sent to these original nativeForkAndXXX methods.
The trick here is to fork before calling the original nativeForkAndXXX
methods, and hook `fork` in libandroid_runtime.so to skip the next
invocation; basically, we're moving the responsibility of process
forking to our own hands.