[Feature Request] Privileged, 'rootless' operation

[jtagcat]

Is your feature request related to a problem? Please describe it.
Some ROMs do not have direct root, yet allow running 'adb root; adb remount', effectively granting full privileges to the system.

Describe the primary solution
adb push can be used to push over files.

Screenshots

/system/etc/permissions # cat permissions_com.stevesoltys.seedvault.xml
<?xml version="1.0" encoding="utf-8"?>
<permissions>
    <privapp-permissions package="com.stevesoltys.seedvault">
        <permission name="android.permission.BACKUP"/>
        <permission name="android.permission.MANAGE_USB"/>
        <permission name="android.permission.INSTALL_PACKAGES"/>
        <permission name="android.permission.WRITE_SECURE_SETTINGS"/>
        <permission name="android.permission.MANAGE_EXTERNAL_STORAGE"/>
    </privapp-permissions>
</permissions>
/system/priv-app/Seedvault # ls
Seedvault.apk  oat
/system/priv-app/Seedvault # ls oat
arm64
/system/priv-app/Seedvault # ls oat/arm64
Seedvault.odex  Seedvault.vdex

I'm aware that oandbackupx does not rely on the backup API, so I'll mention, that iirc, rootful storage can be accessed by a privileged app with.. privileged permissions.

[machiav3lli]

OABX is conceptualized for a whole another use case than seedvault and there's no plan to shift it to a usual privileged app. That said, contributions in this direction are still welcome, as long as they're take a form of option and have less coupling