system/dbus: use syscall dispatcher

This allows dbus op methods and builder to be instrumented.

Signed-off-by: Ophestra <cat@gensokyo.uk>

system/dbus.go

@@ -43,10 +43,10 @@ func (sys *I) ProxyDBus(session, system *dbus.Config, sessionPath, systemPath st
 	d.system = system != nil
 
 	var sessionBus, systemBus dbus.ProxyPair
-	sessionBus[0], systemBus[0] = dbus.Address()
+	sessionBus[0], systemBus[0] = sys.dbusAddress()
 	sessionBus[1], systemBus[1] = sessionPath, systemPath
 	d.out = &linePrefixWriter{println: log.Println, prefix: "(dbus) ", buf: new(strings.Builder)}
-	if final, err := dbus.Finalise(sessionBus, systemBus, session, system); err != nil {
+	if final, err := sys.dbusFinalise(sessionBus, systemBus, session, system); err != nil {
 		if errors.Is(err, syscall.EINVAL) {
 			return nil, newOpErrorMessage("dbus", err,
 				"message bus proxy configuration contains NUL byte", false)
@@ -54,14 +54,14 @@ func (sys *I) ProxyDBus(session, system *dbus.Config, sessionPath, systemPath st
 		return nil, newOpErrorMessage("dbus", err,
 			fmt.Sprintf("cannot finalise message bus proxy: %v", err), false)
 	} else {
-		if msg.IsVerbose() {
-			msg.Verbose("session bus proxy:", session.Args(sessionBus))
+		if sys.isVerbose() {
+			sys.verbose("session bus proxy:", session.Args(sessionBus))
 			if system != nil {
-				msg.Verbose("system bus proxy:", system.Args(systemBus))
+				sys.verbose("system bus proxy:", system.Args(systemBus))
 			}
 
 			// this calls the argsWt String method
-			msg.Verbose("message bus proxy final args:", final.WriterTo)
+			sys.verbose("message bus proxy final args:", final.WriterTo)
 		}
 
 		d.final = final
@@ -85,29 +85,32 @@ type DBusProxyOp struct {
 func (d *DBusProxyOp) Type() Enablement { return Process }
 
 func (d *DBusProxyOp) apply(sys *I) error {
-	msg.Verbosef("session bus proxy on %q for upstream %q", d.final.Session[1], d.final.Session[0])
+	sys.verbosef("session bus proxy on %q for upstream %q", d.final.Session[1], d.final.Session[0])
 	if d.system {
-		msg.Verbosef("system bus proxy on %q for upstream %q", d.final.System[1], d.final.System[0])
+		sys.verbosef("system bus proxy on %q for upstream %q", d.final.System[1], d.final.System[0])
 	}
 
 	d.proxy = dbus.New(sys.ctx, d.final, d.out)
-	if err := d.proxy.Start(); err != nil {
+	if err := sys.dbusProxyStart(d.proxy); err != nil {
 		d.out.Dump()
 		return newOpErrorMessage("dbus", err,
 			fmt.Sprintf("cannot start message bus proxy: %v", err), false)
 	}
-	msg.Verbose("starting message bus proxy", d.proxy)
+	sys.verbose("starting message bus proxy", d.proxy)
 	return nil
 }
 
-func (d *DBusProxyOp) revert(*I, *Criteria) error {
+func (d *DBusProxyOp) revert(sys *I, _ *Criteria) error {
 	// criteria ignored here since dbus is always process-scoped
-	msg.Verbose("terminating message bus proxy")
-	d.proxy.Close()
-	defer msg.Verbose("message bus proxy exit")
-	err := d.proxy.Wait()
+	sys.verbose("terminating message bus proxy")
+	sys.dbusProxyClose(d.proxy)
+
+	exitMessage := "message bus proxy exit"
+	defer func() { sys.verbose(exitMessage) }()
+
+	err := sys.dbusProxyWait(d.proxy)
 	if errors.Is(err, context.Canceled) {
-		msg.Verbose("message bus proxy canceled upstream")
+		exitMessage = "message bus proxy canceled upstream"
 		err = nil
 	}
 	return newOpErrorMessage("dbus", err,

system/dbus_test.go

@@ -1,13 +1,384 @@
 package system
 
 import (
+	"context"
 	"reflect"
 	"slices"
+	"strconv"
 	"strings"
 	"syscall"
 	"testing"
+
+	"hakurei.app/container/stub"
+	"hakurei.app/helper"
+	"hakurei.app/system/dbus"
 )
 
+func TestDBusProxyOp(t *testing.T) {
+	checkOpBehaviour(t, []opBehaviourTestCase{
+		{"dbusProxyStart", 0xdeadbeef, 0xff, &DBusProxyOp{
+			final:  dbusNewFinalSample(4),
+			out:    new(linePrefixWriter), // panics on write
+			system: true,
+		}, []stub.Call{
+			call("verbosef", stub.ExpectArgs{"session bus proxy on %q for upstream %q", []any{"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus", "unix:path=/run/user/1000/bus"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"system bus proxy on %q for upstream %q", []any{"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket", "unix:path=/run/dbus/system_bus_socket"}}, nil, nil),
+			call("dbusProxyStart", stub.ExpectArgs{dbusNewFinalSample(4)}, nil, stub.UniqueError(2)),
+		}, &OpError{
+			Op: "dbus", Err: stub.UniqueError(2),
+			Msg: "cannot start message bus proxy: unique error 2 injected by the test suite",
+		}, nil, nil},
+
+		{"dbusProxyWait", 0xdeadbeef, 0xff, &DBusProxyOp{
+			final: dbusNewFinalSample(3),
+		}, []stub.Call{
+			call("verbosef", stub.ExpectArgs{"session bus proxy on %q for upstream %q", []any{"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus", "unix:path=/run/user/1000/bus"}}, nil, nil),
+			call("dbusProxyStart", stub.ExpectArgs{dbusNewFinalSample(3)}, nil, nil),
+			call("verbose", stub.ExpectArgs{[]any{"starting message bus proxy", ignoreValue{}}}, nil, nil),
+		}, nil, []stub.Call{
+			call("verbose", stub.ExpectArgs{[]any{"terminating message bus proxy"}}, nil, nil),
+			call("dbusProxyClose", stub.ExpectArgs{dbusNewFinalSample(3)}, nil, nil),
+			call("dbusProxyWait", stub.ExpectArgs{dbusNewFinalSample(3)}, nil, stub.UniqueError(1)),
+			call("verbose", stub.ExpectArgs{[]any{"message bus proxy exit"}}, nil, nil),
+		}, &OpError{
+			Op: "dbus", Err: stub.UniqueError(1), Revert: true,
+			Msg: "message bus proxy error: unique error 1 injected by the test suite",
+		}},
+
+		{"success dbusProxyWait cancel", 0xdeadbeef, 0xff, &DBusProxyOp{
+			final:  dbusNewFinalSample(2),
+			system: true,
+		}, []stub.Call{
+			call("verbosef", stub.ExpectArgs{"session bus proxy on %q for upstream %q", []any{"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus", "unix:path=/run/user/1000/bus"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"system bus proxy on %q for upstream %q", []any{"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket", "unix:path=/run/dbus/system_bus_socket"}}, nil, nil),
+			call("dbusProxyStart", stub.ExpectArgs{dbusNewFinalSample(2)}, nil, nil),
+			call("verbose", stub.ExpectArgs{[]any{"starting message bus proxy", ignoreValue{}}}, nil, nil),
+		}, nil, []stub.Call{
+			call("verbose", stub.ExpectArgs{[]any{"terminating message bus proxy"}}, nil, nil),
+			call("dbusProxyClose", stub.ExpectArgs{dbusNewFinalSample(2)}, nil, nil),
+			call("dbusProxyWait", stub.ExpectArgs{dbusNewFinalSample(2)}, nil, context.Canceled),
+			call("verbose", stub.ExpectArgs{[]any{"message bus proxy canceled upstream"}}, nil, nil),
+		}, nil},
+
+		{"success", 0xdeadbeef, 0xff, &DBusProxyOp{
+			final:  dbusNewFinalSample(1),
+			system: true,
+		}, []stub.Call{
+			call("verbosef", stub.ExpectArgs{"session bus proxy on %q for upstream %q", []any{"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus", "unix:path=/run/user/1000/bus"}}, nil, nil),
+			call("verbosef", stub.ExpectArgs{"system bus proxy on %q for upstream %q", []any{"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket", "unix:path=/run/dbus/system_bus_socket"}}, nil, nil),
+			call("dbusProxyStart", stub.ExpectArgs{dbusNewFinalSample(1)}, nil, nil),
+			call("verbose", stub.ExpectArgs{[]any{"starting message bus proxy", ignoreValue{}}}, nil, nil),
+		}, nil, []stub.Call{
+			call("verbose", stub.ExpectArgs{[]any{"terminating message bus proxy"}}, nil, nil),
+			call("dbusProxyClose", stub.ExpectArgs{dbusNewFinalSample(1)}, nil, nil),
+			call("dbusProxyWait", stub.ExpectArgs{dbusNewFinalSample(1)}, nil, nil),
+			call("verbose", stub.ExpectArgs{[]any{"message bus proxy exit"}}, nil, nil),
+		}, nil},
+	})
+
+	checkOpsBuilder(t, "ProxyDBus", []opsBuilderTestCase{
+		{"nil session", 0xcafebabe, func(t *testing.T, sys *I) {
+			wantErr := &OpError{
+				Op: "dbus", Err: ErrDBusConfig,
+				Msg: "attempted to create message bus proxy args without session bus config",
+			}
+			if f, err := sys.ProxyDBus(nil, new(dbus.Config), "", ""); !reflect.DeepEqual(err, wantErr) {
+				t.Errorf("ProxyDBus: error = %v, want %v", err, wantErr)
+			} else if f != nil {
+				t.Errorf("ProxyDBus: f = %p", f)
+			}
+		}, nil, stub.Expect{}},
+
+		{"dbusFinalise NUL", 0xcafebabe, func(_ *testing.T, sys *I) {
+			defer func() {
+				want := "message bus proxy configuration contains NUL byte"
+				if r := recover(); r != want {
+					t.Errorf("MustProxyDBus: panic = %v, want %v", r, want)
+				}
+			}()
+
+			sys.MustProxyDBus(
+				"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus", &dbus.Config{
+					// use impossible value here as an implicit assert that it goes through the stub
+					Talk: []string{"session\x00"}, Filter: true,
+				}, "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket", &dbus.Config{
+					// use impossible value here as an implicit assert that it goes through the stub
+					Talk: []string{"system\x00"}, Filter: true,
+				})
+		}, nil, stub.Expect{Calls: []stub.Call{
+			call("dbusAddress", stub.ExpectArgs{}, [2]string{"unix:path=/run/user/1000/bus", "unix:path=/run/dbus/system_bus_socket"}, nil),
+			call("dbusFinalise", stub.ExpectArgs{
+				dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus"},
+				dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket"},
+				&dbus.Config{Talk: []string{"session\x00"}, Filter: true},
+				&dbus.Config{Talk: []string{"system\x00"}, Filter: true},
+			}, (*dbus.Final)(nil), syscall.EINVAL),
+		}}},
+
+		{"dbusFinalise", 0xcafebabe, func(_ *testing.T, sys *I) {
+			wantErr := &OpError{
+				Op: "dbus", Err: stub.UniqueError(0),
+				Msg: "cannot finalise message bus proxy: unique error 0 injected by the test suite",
+			}
+			if f, err := sys.ProxyDBus(
+				&dbus.Config{
+					// use impossible value here as an implicit assert that it goes through the stub
+					Talk: []string{"session\x00"}, Filter: true,
+				}, &dbus.Config{
+					// use impossible value here as an implicit assert that it goes through the stub
+					Talk: []string{"system\x00"}, Filter: true,
+				},
+				"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus",
+				"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket"); !reflect.DeepEqual(err, wantErr) {
+				t.Errorf("ProxyDBus: error = %v", err)
+			} else if f != nil {
+				t.Errorf("ProxyDBus: f = %p", f)
+			}
+		}, nil, stub.Expect{Calls: []stub.Call{
+			call("dbusAddress", stub.ExpectArgs{}, [2]string{"unix:path=/run/user/1000/bus", "unix:path=/run/dbus/system_bus_socket"}, nil),
+			call("dbusFinalise", stub.ExpectArgs{
+				dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus"},
+				dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket"},
+				&dbus.Config{Talk: []string{"session\x00"}, Filter: true},
+				&dbus.Config{Talk: []string{"system\x00"}, Filter: true},
+			}, (*dbus.Final)(nil), stub.UniqueError(0)),
+		}}},
+
+		{"full", 0xcafebabe, func(_ *testing.T, sys *I) {
+			sys.MustProxyDBus(
+				"/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus", &dbus.Config{
+					// use impossible value here as an implicit assert that it goes through the stub
+					Talk: []string{"session\x00"}, Filter: true,
+				}, "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket", &dbus.Config{
+					// use impossible value here as an implicit assert that it goes through the stub
+					Talk: []string{"system\x00"}, Filter: true,
+				})
+		}, []Op{
+			&DBusProxyOp{
+				final:  dbusNewFinalSample(0),
+				system: true,
+			},
+		}, stub.Expect{Calls: []stub.Call{
+			call("dbusAddress", stub.ExpectArgs{}, [2]string{"unix:path=/run/user/1000/bus", "unix:path=/run/dbus/system_bus_socket"}, nil),
+			call("dbusFinalise", stub.ExpectArgs{
+				dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus"},
+				dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket"},
+				&dbus.Config{Talk: []string{"session\x00"}, Filter: true},
+				&dbus.Config{Talk: []string{"system\x00"}, Filter: true},
+			}, dbusNewFinalSample(0), nil),
+			call("isVerbose", stub.ExpectArgs{}, true, nil),
+			call("verbose", stub.ExpectArgs{[]any{"session bus proxy:", []string{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus", "--filter", "--talk=session\x00"}}}, nil, nil),
+			call("verbose", stub.ExpectArgs{[]any{"system bus proxy:", []string{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket", "--filter", "--talk=system\x00"}}}, nil, nil),
+			call("verbose", stub.ExpectArgs{[]any{"message bus proxy final args:", helper.MustNewCheckedArgs([]string{"unique", "value", "0", "injected", "by", "the", "test", "suite"})}}, nil, nil),
+		}}},
+	})
+
+	checkOpIs(t, []opIsTestCase{
+		{"nil", (*DBusProxyOp)(nil), (*DBusProxyOp)(nil), false},
+		{"zero", new(DBusProxyOp), new(DBusProxyOp), false},
+
+		{"system differs", &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: false,
+		}, &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, false},
+
+		{"wt differs", &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1001/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, false},
+
+		{"final system upstream differs", &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket\x00"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, false},
+
+		{"final session upstream differs", &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1001/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, false},
+
+		{"final system differs", &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.1/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, false},
+
+		{"final session differs", &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1001/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, false},
+
+		{"equals", &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, &DBusProxyOp{final: &dbus.Final{
+			Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus"},
+			System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket"},
+
+			SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+			SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"unix", "/run/dbus/system_bus_socket"}}}},
+
+			WriterTo: helper.MustNewCheckedArgs([]string{
+				"--filter", "unix:path=/run/user/1000/bus", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/bus",
+				"--filter", "unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/b186c281d9e83a39afdc66d964ef99c6/system_bus_socket",
+			}),
+		}, system: true,
+		}, true},
+	})
+
+	checkOpMeta(t, []opMetaTestCase{
+		{"dbus", new(DBusProxyOp),
+			Process, "/proc/nonexistent",
+			"(invalid dbus proxy)"},
+	})
+}
+
+func dbusNewFinalSample(v int) *dbus.Final {
+	return &dbus.Final{
+		Session: dbus.ProxyPair{"unix:path=/run/user/1000/bus", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/bus"},
+		System:  dbus.ProxyPair{"unix:path=/run/dbus/system_bus_socket", "/tmp/hakurei.0/99dd71ee2146369514e0d10783368f8f/system_bus_socket"},
+
+		SessionUpstream: []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/user/1000/bus"}}}},
+		SystemUpstream:  []dbus.AddrEntry{{Method: "unix", Values: [][2]string{{"path", "/run/dbus/system_bus_socket"}}}},
+
+		WriterTo: helper.MustNewCheckedArgs([]string{"unique", "value", strconv.Itoa(v), "injected", "by", "the", "test", "suite"}),
+	}
+}
+
 func TestLinePrefixWriter(t *testing.T) {
 	testCases := []struct {
 		name    string

system/dispatcher.go

@@ -1,6 +1,9 @@
 package system
 
-import "hakurei.app/system/acl"
+import (
+	"hakurei.app/system/acl"
+	"hakurei.app/system/dbus"
+)
 
 // syscallDispatcher provides methods that make state-dependent system calls as part of their behaviour.
 // syscallDispatcher is embedded in [I], so all methods must be unexported.
@@ -13,6 +16,18 @@ type syscallDispatcher interface {
 	// aclUpdate provides [acl.Update].
 	aclUpdate(name string, uid int, perms ...acl.Perm) error
 
+	// dbusAddress provides [dbus.Address].
+	dbusAddress() (session, system string)
+	// dbusFinalise provides [dbus.Finalise].
+	dbusFinalise(sessionBus, systemBus dbus.ProxyPair, session, system *dbus.Config) (final *dbus.Final, err error)
+	// dbusProxyStart provides the Start method of [dbus.Proxy].
+	dbusProxyStart(proxy *dbus.Proxy) error
+	// dbusProxyClose provides the Close method of [dbus.Proxy].
+	dbusProxyClose(proxy *dbus.Proxy)
+	// dbusProxyWait provides the Wait method of [dbus.Proxy].
+	dbusProxyWait(proxy *dbus.Proxy) error
+
+	isVerbose() bool
 	verbose(v ...any)
 	verbosef(format string, v ...any)
 }
@@ -26,5 +41,18 @@ func (k direct) aclUpdate(name string, uid int, perms ...acl.Perm) error {
 	return acl.Update(name, uid, perms...)
 }
 
+func (k direct) dbusAddress() (session, system string) {
+	return dbus.Address()
+}
+
+func (k direct) dbusFinalise(sessionBus, systemBus dbus.ProxyPair, session, system *dbus.Config) (final *dbus.Final, err error) {
+	return dbus.Finalise(sessionBus, systemBus, session, system)
+}
+
+func (k direct) dbusProxyStart(proxy *dbus.Proxy) error { return proxy.Start() }
+func (k direct) dbusProxyClose(proxy *dbus.Proxy)       { proxy.Close() }
+func (k direct) dbusProxyWait(proxy *dbus.Proxy) error  { return proxy.Wait() }
+
+func (k direct) isVerbose() bool                { return msg.IsVerbose() }
 func (direct) verbose(v ...any)                 { msg.Verbose(v...) }
 func (direct) verbosef(format string, v ...any) { msg.Verbosef(format, v...) }

system/dispatcher_test.go

@@ -1,12 +1,15 @@
 package system
 
 import (
+	"os"
 	"reflect"
 	"slices"
 	"testing"
+	"unsafe"
 
 	"hakurei.app/container/stub"
 	"hakurei.app/system/acl"
+	"hakurei.app/system/dbus"
 )
 
 // call initialises a [stub.Call].
@@ -197,9 +200,85 @@ func (k *kstub) aclUpdate(name string, uid int, perms ...acl.Perm) error {
 		stub.CheckArgReflect(k.Stub, "perms", perms, 2))
 }
 
+func (k *kstub) dbusAddress() (session, system string) {
+	k.Helper()
+	ret := k.Expects("dbusAddress").Ret.([2]string)
+	return ret[0], ret[1]
+}
+
+func (k *kstub) dbusFinalise(sessionBus, systemBus dbus.ProxyPair, session, system *dbus.Config) (final *dbus.Final, err error) {
+	k.Helper()
+	expect := k.Expects("dbusFinalise")
+
+	final = expect.Ret.(*dbus.Final)
+	err = expect.Error(
+		stub.CheckArg(k.Stub, "sessionBus", sessionBus, 0),
+		stub.CheckArg(k.Stub, "systemBus", systemBus, 1),
+		stub.CheckArgReflect(k.Stub, "session", session, 2),
+		stub.CheckArgReflect(k.Stub, "system", system, 3))
+	if err != nil {
+		final = nil
+	}
+	return
+}
+
+func (k *kstub) dbusProxyStart(proxy *dbus.Proxy) error {
+	k.Helper()
+	return k.dbusProxySCW(k.Expects("dbusProxyStart"), proxy)
+}
+func (k *kstub) dbusProxyClose(proxy *dbus.Proxy) {
+	k.Helper()
+	if k.dbusProxySCW(k.Expects("dbusProxyClose"), proxy) != nil {
+		k.Fail()
+	}
+}
+func (k *kstub) dbusProxyWait(proxy *dbus.Proxy) error {
+	k.Helper()
+	return k.dbusProxySCW(k.Expects("dbusProxyWait"), proxy)
+}
+func (k *kstub) dbusProxySCW(expect *stub.Call, proxy *dbus.Proxy) error {
+	k.Helper()
+	v := reflect.ValueOf(proxy).Elem()
+
+	if ctxV := v.FieldByName("ctx"); ctxV.IsNil() {
+		k.Errorf("proxy: ctx = %s", ctxV.String())
+		return os.ErrInvalid
+	}
+
+	finalV := v.FieldByName("final")
+	if gotFinal := reflect.NewAt(finalV.Type(), unsafe.Pointer(finalV.UnsafeAddr())).Elem().Interface().(*dbus.Final); !reflect.DeepEqual(gotFinal, expect.Args[0]) {
+		k.Errorf("proxy: final = %#v, want %#v", gotFinal, expect.Args[0])
+		return os.ErrInvalid
+	}
+
+	outputV := v.FieldByName("output")
+	if _, ok := reflect.NewAt(outputV.Type(), unsafe.Pointer(outputV.UnsafeAddr())).Elem().Interface().(*linePrefixWriter); !ok {
+		k.Errorf("proxy: output = %s", outputV.String())
+		return os.ErrInvalid
+	}
+
+	return expect.Err
+}
+
+func (k *kstub) isVerbose() bool { k.Helper(); return k.Expects("isVerbose").Ret.(bool) }
+
+// ignoreValue marks a value to be ignored by the test suite.
+type ignoreValue struct{}
+
 func (k *kstub) verbose(v ...any) {
 	k.Helper()
-	if k.Expects("verbose").Error(
+	expect := k.Expects("verbose")
+
+	// translate ignores in v
+	if want, ok := expect.Args[0].([]any); ok && len(v) == len(want) {
+		for i, a := range want {
+			if _, ok = a.(ignoreValue); ok {
+				v[i] = ignoreValue{}
+			}
+		}
+	}
+
+	if expect.Error(
 		stub.CheckArgReflect(k.Stub, "v", v, 0)) != nil {
 		k.FailNow()
 	}