Atmosphere/docs/modules/set_mitm.md

set_mitm

set_mitm is a sysmodule that enables intercepting requests to the system settings service.

Atmosphère Extensions

set_mitm intercepts the GetFirmwareVersion command, if the requester is qlaunch or maintenance.
It modifies the display_version field of the returned system version, causing the version to display
in settings as #.#.# (AMS #.#.#). This allows users to easily verify what version of Atmosphère they are running.

set_mitm also intercepts the GetSettingsItemValueSize and GetSettingsItemValue commands for all requesters.
It does so in order to enable user configuration of system settings, which are parsed from atmosphere/system_settings.ini on boot.
The format for settings is described below.

Atmosphère Settings Format

Settings are parsed from the atmosphere/system_settings.ini file during the boot process. This file is a normal ini file,
with some specific interpretations.

The standard representation of a system setting's identifier takes the form name!key. This is represented within
system_settings.ini as a section name, with an entry key. For example:

[name]
key = ...

System settings can have variable types (strings, integral values, byte arrays, etc). To accommodate this, system_settings.ini
must store values as a type_identifier!value_store pair. A number of different types are supported, with identifiers detailed below.
Please note that a malformed value string will cause a fatal error to occur on boot. A full example of a custom setting is given below
(setting eupld!upload_enabled = 0), for posterity:

[eupld]
upload_enabled = u8!0x0

Supported Types

• Strings
  • Type identifiers: str, string
  • The value string is used directly as the setting, with null terminator appended.
• Integral types
  • Type identifiers: u8, u16, u32, u64
  • The value string is parsed via a call to strtoul(value, NULL, 0).
  • Setting bitwidth is determined by the identifier (8 for 1 byte, 16 for 2 bytes, and so on).
• Raw bytes
  • Type identifiers: hex, bytes
  • The value string is parsed as a hexadecimal string.
    • The value string must be of even length, or a fatal error will be thrown on parse.

Atmosphère Custom Settings

At the time of writing, Atmosphère implements two custom settings, found in the atmosphere section.\

While not used for set_mitm, power_menu_reboot_function is loaded and controls the reboot behaviour of the console. By default, this value
is "payload", where the console will automatically reboot into the RCM payload stored in sdmc:/atmosphere/reboot_payload.bin.
(This payload is also used for fatal, upon a serious crash.) Setting the value to "rcm" reboots directly into RCM, and setting the value
to "normal" skips these behaviours.

[atmosphere]
power_menu_reboot_function = str!payload

dmnt_cheats_enabled_by_default controls the behaviour of dmnt's cheat functionality. By default, this value is "0x1", enabling any cheats
defined by the user. Check cheats for more information about Atmosphère's cheat functionality.

[atmosphere]
dmnt_cheats_enabled_by_default = u8!0x1