xcode - Once jailbroken, will iOS apps run with root privilege?

Question

Once an iOS device is jailbroken, we can build jailbreak apps (with theos) and it gets installed in the /Applications directory where the preloaded apps run with root privileges. If an app is built with Xcode, once it is installed, it gets into the /private/var/mobile/Applications/ folder, which is supposed to have Apple sandbox enforced (before jailbreak).

So, the questions I have are:

1. For a jailbroken device, will the apps in /private/var/mobile/Applications/ execute with root privileges or with mobile user privileges?

2. In case of Android, once rooted, the apps will have to gain root privileges by executing the su command. Is it the case when it comes to iOS as well?

I would like to understand the difference between these two development options (Theos / Xcode) and how it affects what operations my app can perform.

Answer 1

Long story short: no.

Jailbreaking is a necessary but not sufficient condition for gaining root. Apps will still be sandboxed by default.

What you can do for making your app run with root privileges is creating a startup shell script that has root:wheel ownership and 755 permissions, then create your actual executable with the same ownership, 7555 as permissions (i. e. set its "setuid" bit), then call setuid(0); from within main(), before calling UIApplicationMain().