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//go:build linux
package hostsvc
import (
"context"
"encoding/hex"
"fmt"
"os"
"path/filepath"
"strconv"
"sync"
sd "github.com/coreos/go-systemd/v22/dbus"
"github.com/godbus/dbus/v5"
)
const (
systemdDest = "org.freedesktop.systemd1"
systemdPath = dbus.ObjectPath("/org/freedesktop/systemd1")
managerIfc = "org.freedesktop.systemd1.Manager"
)
type bus interface {
StartTransientUnit(ctx context.Context, name string, props []sd.Property, ch chan<- string) error
StopUnit(ctx context.Context, name string, ch chan<- string) error
ResetFailedUnit(ctx context.Context, name string) error
UnitProperties(ctx context.Context, name string) (map[string]any, error)
ServiceProperties(ctx context.Context, name string) (map[string]any, error)
ListUnitsByPatterns(ctx context.Context, patterns []string) ([]sd.UnitStatus, error)
UnitByPIDFD(ctx context.Context, fd int) (string, string, error)
Version(ctx context.Context) (string, error)
ManagerStarted(ctx context.Context) (uint64, error)
Subscribe(ctx context.Context, ch chan<- *dbus.Signal) error
Close()
}
type dialError struct{ err error }
func (e dialError) Error() string { return "hostsvc: dialing the user manager: " + e.err.Error() }
func (e dialError) Unwrap() error { return e.err }
func PrivateSocketPath() string {
dir := os.Getenv("XDG_RUNTIME_DIR")
if dir == "" {
dir = filepath.Join("/run/user", strconv.Itoa(os.Getuid()))
}
return filepath.Join(dir, "systemd", "private")
}
func dialPrivate(path string) func(ctx context.Context) (bus, error) {
return func(ctx context.Context) (bus, error) {
var mu sync.Mutex
var conns []*dbus.Conn
dialOne := func() (*dbus.Conn, error) {
c, err := dbus.Dial("unix:path=" + path)
if err != nil {
return nil, err
}
mu.Lock()
conns = append(conns, c)
mu.Unlock()
if err := ctx.Err(); err != nil {
c.Close()
return nil, err
}
if err := c.Auth([]dbus.Auth{dbus.AuthExternal(strconv.Itoa(os.Getuid()))}); err != nil {
c.Close()
return nil, err
}
return c, nil
}
watchdog := context.AfterFunc(ctx, func() {
mu.Lock()
defer mu.Unlock()
for _, c := range conns {
c.Close()
}
})
conn, err := sd.NewConnection(dialOne)
if !watchdog() {
if conn != nil {
conn.Close()
}
return nil, dialError{fmt.Errorf("%s: %w", path, ctx.Err())}
}
if err != nil {
return nil, dialError{fmt.Errorf("%s: %w", path, err)}
}
return &sdBus{conn: conn, raw: conns[0], sig: conns[1]}, nil
}
}
type sdBus struct {
conn *sd.Conn
raw *dbus.Conn
sig *dbus.Conn
}
func (b *sdBus) StartTransientUnit(ctx context.Context, name string, props []sd.Property, ch chan<- string) error {
_, err := b.conn.StartTransientUnitContext(ctx, name, "fail", props, ch)
return err
}
func (b *sdBus) StartUnit(ctx context.Context, name string, ch chan<- string) error {
_, err := b.conn.StartUnitContext(ctx, name, "replace", ch)
return err
}
func (b *sdBus) EnableUnitFiles(ctx context.Context, names []string) error {
_, _, err := b.conn.EnableUnitFilesContext(ctx, names, false, false)
return err
}
func (b *sdBus) DisableUnitFiles(ctx context.Context, names []string) error {
_, err := b.conn.DisableUnitFilesContext(ctx, names, false)
return err
}
func (b *sdBus) StopUnit(ctx context.Context, name string, ch chan<- string) error {
_, err := b.conn.StopUnitContext(ctx, name, "replace", ch)
return err
}
func (b *sdBus) ResetFailedUnit(ctx context.Context, name string) error {
return b.conn.ResetFailedUnitContext(ctx, name)
}
func (b *sdBus) UnitProperties(ctx context.Context, name string) (map[string]any, error) {
return b.conn.GetUnitPropertiesContext(ctx, name)
}
func (b *sdBus) ServiceProperties(ctx context.Context, name string) (map[string]any, error) {
return b.conn.GetUnitTypePropertiesContext(ctx, name, "Service")
}
func (b *sdBus) ListUnitsByPatterns(ctx context.Context, patterns []string) ([]sd.UnitStatus, error) {
return b.conn.ListUnitsByPatternsContext(ctx, nil, patterns)
}
func (b *sdBus) UnitByPIDFD(ctx context.Context, fd int) (string, string, error) {
var path dbus.ObjectPath
var name string
var inv []byte
err := b.raw.Object(systemdDest, systemdPath).
CallWithContext(ctx, managerIfc+".GetUnitByPIDFD", 0, dbus.UnixFD(fd)).
Store(&path, &name, &inv)
if err != nil {
return "", "", err
}
return name, hex.EncodeToString(inv), nil
}
func (b *sdBus) Version(ctx context.Context) (string, error) {
var v dbus.Variant
err := b.raw.Object(systemdDest, systemdPath).
CallWithContext(ctx, "org.freedesktop.DBus.Properties.Get", 0, managerIfc, "Version").
Store(&v)
if err != nil {
return "", err
}
s, ok := v.Value().(string)
if !ok {
return "", fmt.Errorf("hostsvc: the manager's Version is a %T, not a string", v.Value())
}
return s, nil
}
func (b *sdBus) ManagerStarted(ctx context.Context) (uint64, error) {
var v dbus.Variant
err := b.raw.Object(systemdDest, systemdPath).
CallWithContext(ctx, "org.freedesktop.DBus.Properties.Get", 0, managerIfc, "UserspaceTimestampMonotonic").
Store(&v)
if err != nil {
return 0, err
}
n, ok := v.Value().(uint64)
if !ok {
return 0, fmt.Errorf("hostsvc: the manager's UserspaceTimestampMonotonic is a %T, not a uint64", v.Value())
}
return n, nil
}
func (b *sdBus) Subscribe(ctx context.Context, ch chan<- *dbus.Signal) error {
b.sig.Signal(ch)
return b.sig.Object(systemdDest, systemdPath).CallWithContext(ctx, managerIfc+".Subscribe", 0).Err
}
func (b *sdBus) Close() {
b.conn.Close()
}
