source/system: Add reading vendor information

docs/usage/customization-guide.md

@@ -979,6 +979,8 @@ The following features are available for matching:
 |                  |              | **`<sysfs-attribute>`** | string | Sysfs network interface attribute, available attributes: `dax`, `rotational`, `nr_zones`, `zoned` |
 | **`system.osrelease`** | attribute |       |            | System identification data from `/etc/os-release` |
 |                  |              | **`<parameter>`** | string | One parameter from `/etc/os-release` |
+| **`system.dmiid`** | attribute |       |            | DMI identification data from `/sys/devices/virtual/dmi/id/` |
+|                  |              | **`sys_vendor`** | string | Vendor name from `/sys/devices/virtual/dmi/id/sys_vendor` |
 | **`system.name`** | attribute   |          |            | System name information |
 |                  |              | **`nodename`** | string | Name of the kubernetes node object |
 | **`usb.device`** | instance     |          |            | USB devices present in the system |

examples/nodefeature.yaml

@@ -65,6 +65,9 @@ spec:
           VERSION_ID: "22.04"
           VERSION_ID.major: "22"
           VERSION_ID.minor: "04"
+      system.dmiid:
+        elements:
+          sys_vendor: VendorUnknown
     flags:
       cpu.cpuid:
         elements:

source/system/system.go

@@ -43,6 +43,7 @@
 const (
 	OsReleaseFeature = "osrelease"
 	NameFeature      = "name"
+	DmiIdFeature     = "dmiid"
 )
 
 // systemSource implements the FeatureSource and LabelSource interfaces.
@@ -101,6 +102,22 @@
 		}
 	}
 
+	// Get DMI ID attributes
+	dmiIDAttributeNames := []string{"sys_vendor"}
+	dmiAttrs := make(map[string]string)
+	for _, name := range dmiIDAttributeNames {
+		val, err := getDmiIDAttribute(name)
+		if err != nil {
+			klog.ErrorS(err, "failed to get DMI entry", "attributeName", name)
+		} else {
+			dmiAttrs[name] = val
+		}
+	}
+
+	if len(dmiAttrs) > 0 {
+		s.features.Attributes[DmiIdFeature] = nfdv1alpha1.NewAttributeFeatures(dmiAttrs)
+	}
+
 	klog.V(3).InfoS("discovered features", "featureSource", s.Name(), "features", utils.DelayedDumper(s.features))
 
 	return nil
@@ -153,6 +170,16 @@
 	return components
 }
 
+// Read /sys/devices/virtual/dmi/id attribute
+func getDmiIDAttribute(name string) (string, error) {
+	s, err := os.ReadFile(hostpath.SysfsDir.Path("devices/virtual/dmi/id/", name))
+	if err != nil {
+		return "", err
+	}
+
+	return strings.TrimSpace(string(s)), nil
+}
+
 func init() {
 	source.Register(&src)
 }