nixpkgs/nixos/modules/hardware/facter/lib.nix
Jörg Thalheim ab49e37a02 nixos/facter: add core library and system detection
This adds foundational functionality for nixos-facter hardware detection:

- lib.nix: Internal helper functions for querying facter reports
  - hasCpu/hasAmdCpu/hasIntelCpu: CPU vendor detection
  - collectDrivers: Extract driver_modules from hardware entries
  - toZeroPaddedHex: Format USB device IDs (for fingerprint matching)

- system.nix: Auto-detect nixpkgs.hostPlatform from facter report
  Automatically sets the correct platform (x86_64-linux, aarch64-linux, etc.)
  based on the hardware report, reducing manual configuration.

This builds on the base infrastructure added in PR #450303 and provides
the foundation for upcoming hardware detection modules (boot, networking,
graphics, etc.).

Part of the incremental upstreaming effort from:
https://github.com/nix-community/nixos-facter-modules
2025-10-22 12:38:46 +02:00

60 lines
1.3 KiB
Nix

# Internal library functions for hardware.facter modules
# Eventually we can think about moving this under lib/
# These are facter-specific helpers for querying nixos-facter reports
lib:
let
inherit (lib) assertMsg;
# Query if a facter report contains a CPU with the given vendor name
hasCpu =
name:
{
hardware ? { },
...
}:
let
cpus = hardware.cpu or [ ];
in
assert assertMsg (hardware != { }) "no hardware entries found in the report";
assert assertMsg (cpus != [ ]) "no cpu entries found in the report";
builtins.any (
{
vendor_name ? null,
...
}:
assert assertMsg (vendor_name != null) "detail.vendor_name not found in cpu entry";
vendor_name == name
) cpus;
# Extract all driver_modules from a list of hardware entries
collectDrivers = list: lib.catAttrs "driver_modules" list;
# Convert number to zero-padded 4-digit hex string (for USB device IDs)
toZeroPaddedHex =
n:
let
hex = lib.toHexString n;
len = builtins.stringLength hex;
in
if len == 1 then
"000${hex}"
else if len == 2 then
"00${hex}"
else if len == 3 then
"0${hex}"
else
hex;
in
{
inherit
hasCpu
collectDrivers
toZeroPaddedHex
;
hasAmdCpu = hasCpu "AuthenticAMD";
hasIntelCpu = hasCpu "GenuineIntel";
}