internal/uevent: decode uevent messages

The wire format and behaviour is entirely undocumented. This is implemented by reading lib/kobject_uevent.c, with testdata collected from the internal/rosa kernel. Signed-off-by: Ophestra <cat@gensokyo.uk>
2026-03-28 00:10:50 +09:00
parent 30f459e690
commit 713bff3eb0
3 changed files with 339 additions and 8 deletions
--- a/internal/uevent/message_test.go
+++ b/internal/uevent/message_test.go
@@ -0,0 +1,126 @@
+package uevent_test
+
+import (
+	"syscall"
+	"testing"
+
+	"hakurei.app/internal/uevent"
+)
+
+func TestMessage(t *testing.T) {
+	t.Parallel()
+
+	testCases := []struct {
+		name     string
+		v        uevent.Message
+		want     string
+		wantErr  error
+		wantErrE error
+
+		s string
+	}{
+		{"sample virtio-sound-pci add", uevent.Message{
+			Action:  uevent.KOBJ_ADD,
+			DevPath: "/devices/pci0000:00/0000:00:04.0/virtio1",
+			Env: []string{
+				"ACTION=add",
+				"DEVPATH=/devices/pci0000:00/0000:00:04.0/virtio1",
+				"SUBSYSTEM=virtio",
+				"MODALIAS=virtio:d00000019v00001AF4",
+				"SEQNUM=779",
+			},
+		}, "add@/devices/pci0000:00/0000:00:04.0/virtio1\x00" +
+			"ACTION=add\x00" +
+			"DEVPATH=/devices/pci0000:00/0000:00:04.0/virtio1\x00" +
+			"SUBSYSTEM=virtio\x00" +
+			"MODALIAS=virtio:d00000019v00001AF4\x00" +
+			"SEQNUM=779\x00",
+			nil, nil, `add event on /devices/pci0000:00/0000:00:04.0/virtio1:
+ACTION=add
+DEVPATH=/devices/pci0000:00/0000:00:04.0/virtio1
+SUBSYSTEM=virtio
+MODALIAS=virtio:d00000019v00001AF4
+SEQNUM=779`},
+
+		{"sample virtio-sound-pci bind", uevent.Message{
+			Action:  uevent.KOBJ_BIND,
+			DevPath: "/devices/pci0000:00/0000:00:04.0",
+			Env: []string{
+				"ACTION=bind",
+				"DEVPATH=/devices/pci0000:00/0000:00:04.0",
+				"SUBSYSTEM=pci",
+				"DRIVER=virtio-pci",
+				"PCI_CLASS=40100",
+				"PCI_ID=1AF4:1059",
+				"PCI_SUBSYS_ID=1AF4:1100",
+				"PCI_SLOT_NAME=0000:00:04.0",
+				"MODALIAS=pci:v00001AF4d00001059sv00001AF4sd00001100bc04sc01i00",
+				"SEQNUM=780",
+			},
+		}, "bind@/devices/pci0000:00/0000:00:04.0\x00" +
+			"ACTION=bind\x00" +
+			"DEVPATH=/devices/pci0000:00/0000:00:04.0\x00" +
+			"SUBSYSTEM=pci\x00" +
+			"DRIVER=virtio-pci\x00" +
+			"PCI_CLASS=40100\x00" +
+			"PCI_ID=1AF4:1059\x00" +
+			"PCI_SUBSYS_ID=1AF4:1100\x00" +
+			"PCI_SLOT_NAME=0000:00:04.0\x00" +
+			"MODALIAS=pci:v00001AF4d00001059sv00001AF4sd00001100bc04sc01i00\x00" +
+			"SEQNUM=780\x00", nil, nil, `bind event on /devices/pci0000:00/0000:00:04.0:
+ACTION=bind
+DEVPATH=/devices/pci0000:00/0000:00:04.0
+SUBSYSTEM=pci
+DRIVER=virtio-pci
+PCI_CLASS=40100
+PCI_ID=1AF4:1059
+PCI_SUBSYS_ID=1AF4:1100
+PCI_SLOT_NAME=0000:00:04.0
+MODALIAS=pci:v00001AF4d00001059sv00001AF4sd00001100bc04sc01i00
+SEQNUM=780`},
+
+		{"zero devpath env", uevent.Message{
+			Action: uevent.KOBJ_MOVE,
+		}, "move@\x00", nil, nil, "move event:"},
+
+		{"d final NUL e bad action", uevent.Message{
+			Action: 0xbad,
+		}, "move@\x00truncated", &uevent.MessageError{
+			Data:    "move@\x00truncated",
+			Section: "truncated",
+			Kind:    uevent.MErrorKindFinalNUL,
+		}, syscall.EINVAL, "unsupported kobject_action 2989 event:"},
+
+		{"bad action", uevent.Message{
+			Action: 0xbad,
+		}, "nonexistent@\x00", uevent.UnsupportedActionError(
+			"nonexistent",
+		), syscall.EINVAL, "unsupported kobject_action 2989 event:"},
+
+		{"d header sep e bad action", uevent.Message{
+			Action: 0xbad,
+		}, "move\x00", &uevent.MessageError{
+			Data:    "move\x00",
+			Section: "move",
+			Kind:    uevent.MErrorKindHeaderSep,
+		}, syscall.EINVAL, "unsupported kobject_action 2989 event:"},
+
+		{"d missing header e bad action", uevent.Message{
+			Action: 0xbad,
+		}, "move", uevent.MissingHeaderError(
+			"move",
+		), syscall.EINVAL, "unsupported kobject_action 2989 event:"},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			adeB(t, "", tc.v, tc.want, tc.wantErr, tc.wantErrE)
+			t.Run("string", func(t *testing.T) {
+				if got := tc.v.String(); got != tc.s {
+					t.Errorf("String: %q, want %q", got, tc.s)
+				}
+			})
+		})
+	}
+}