Magisk

Developer Guides

Please read through Magisk Details before reading the following guides. If you are developing a module, pay extra attention to the Magic Mount section.

Magisk Modules

A Magisk module is a folder placed in /data/adb/modules with a structure below:

/data/adb/modules
├── .
├── .
|
├── $MODID                  <--- The folder is named with the ID of the module
│   │
│   │      *** Module Identity ***
│   │
│   ├── module.prop         <--- This files stores the metadata of the module
│   │
│   │      *** Status files ***
│   │
│   ├── skip_mount          <--- If exists, Magisk will NOT mount your files
│   ├── disable             <--- If exists, the module will be disabled
│   ├── remove              <--- If exists, the module will be removed next reboot
│   │
│   │      *** Scripts ***
│   │
│   ├── post-fs-data.sh     <--- This script will be executed in post-fs-data
│   ├── service.sh          <--- This script will be executed in late_start service
|   ├── uninstall.sh        <--- This script will be executed when Magisk removes your module
│   │
│   │      *** Resetprop Files ***
│   │
│   ├── system.prop         <--- This file will be loaded as system properties by resetprop
│   │
│   │      *** Module contents ***
│   │
│   ├── system              <--- This folder will be Magic Mounted if skip_mount does not exists
│   │   ├── .
│   │   ├── .
│   │   └── .
│   │
│   │      *** Auto Generated by Magisk ***
│   │
│   ├── vendor              <--- A symlink to $MODID/system/vendor
│   ├── product             <--- A symlink to $MODID/system/product
│   │
│   │      *** Others ***
│   │
│   ├── .                   <--- Any additional files / folders are allowed
│   └── .
|
├── another_module
│   ├── .
│   └── .
├── .
├── .

As long as a folder follows the structure above, it will be recognized as a module.

Here is the strict format of module.prop:

id=<string>
name=<string>
version=<string>
versionCode=<int>
author=<string>
description=<string>

Magisk Module Installer

The official Magisk Module installer is hosted here.

That repo is a starting point for creating a Magisk module installer zip. Here are some details:

Submit Modules

You can submit a module to Magisk-Module-Repo so users can download your module directly in Magisk Manager. Before submitting, follow the instructions in the previous section to create a valid installer for your module. You can then create a request for submission via this link: submission.

Boot Scripts

In Magisk, you can run boot scripts in 2 different modes: post-fs-data and late_start service mode.

In Magisk, there are also 2 kinds of scripts: general scripts and module scripts.

Magisk’s internal busybox’s path $BBPATH is always prepended in PATH. This means all commands you call in scripts are always using busybox unless the applet is not included. This makes sure that your script always run in a predictable environment and always have the full suite of commands regardless of which Android version it is running on.

Root Directory Overlay System

Since / is read-only in system-as-root devices, Magisk provides an overlay system, allowing developers to patch files / add new rc scripts. Additional files shall be placed in the overlay.d folder in the ramdisk, and they will have the following restrictions:

Remove Files

How to remove a file systemless-ly? To actually make the file disappear is complicated (possible, not worth the effort). Replacing it with a dummy file should be good enough! Create an empty file with the same name and place it in the same path within a module, it shall replace your target file with a dummy file.

Remove Folders

Same as mentioned above, actually making the folder disappear is not worth the effort. Replacing it with an empty folder should be good enough! A handy trick for module developers is to add the folder you want to remove into the REPLACE list within install.sh. If your module doesn’t provide a corresponding folder, it will create an empty folder, and automatically add .replace into the empty folder so the dummy folder will properly replace the one in /system.