1 files changed, 162 insertions, 0 deletions
diff --git a/state.go b/state.go
new file mode 100644
index 00000000..22047085
--- /dev/null
+++ b/state.go
@@ -0,0 +1,162 @@
+package main
+
+import (
+	"encoding/gob"
+	"errors"
+	"flag"
+	"fmt"
+	"io/fs"
+	"os"
+	"os/exec"
+	"path"
+	"strconv"
+)
+
+// we unfortunately have to assume there are never races between processes
+// this and launcher should eventually be replaced by a server process
+
+var (
+	stateActionEarly  bool
+	statePath         string
+	cleanupCandidate  []string
+	xcbActionComplete bool
+)
+
+type launcherState struct {
+	PID      int
+	Launcher string
+	Argv     []string
+	Command  []string
+}
+
+func init() {
+	flag.BoolVar(&stateActionEarly, "state", false, "query state value of current active launchers")
+}
+
+func tryState() {
+	if !stateActionEarly {
+		return
+	}
+
+	launchers, err := readLaunchers()
+	if err != nil {
+		fmt.Println("Error reading launchers:", err)
+		os.Exit(1)
+	}
+
+	fmt.Println("\tPID\tLauncher")
+	for _, state := range launchers {
+		fmt.Printf("\t%d\t%s\nCommand: %s\nArgv: %s\n", state.PID, state.Launcher, state.Command, state.Argv)
+	}
+
+	os.Exit(0)
+}
+
+func registerRevertPath(p string) {
+	cleanupCandidate = append(cleanupCandidate, p)
+}
+
+// called after process start, before wait
+func registerProcess(uid string, cmd *exec.Cmd) error {
+	statePath = path.Join(runDir, uid, strconv.Itoa(cmd.Process.Pid))
+	state := launcherState{
+		PID:      cmd.Process.Pid,
+		Launcher: cmd.Path,
+		Argv:     cmd.Args,
+		Command:  command,
+	}
+
+	if err := os.Mkdir(path.Join(runDir, uid), 0700); err != nil && !errors.Is(err, fs.ErrExist) {
+		return err
+	}
+
+	if f, err := os.OpenFile(statePath, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600); err != nil {
+		return err
+	} else {
+		defer func() {
+			if f.Close() != nil {
+				// unreachable
+				panic("state file closed prematurely")
+			}
+		}()
+		return gob.NewEncoder(f).Encode(state)
+	}
+}
+
+func readLaunchers() ([]*launcherState, error) {
+	var f *os.File
+	var r []*launcherState
+	launcherPrefix := path.Join(runDir, ego.Uid)
+
+	if pl, err := os.ReadDir(launcherPrefix); err != nil {
+		return nil, err
+	} else {
+		for _, e := range pl {
+			if err = func() error {
+				if f, err = os.Open(path.Join(launcherPrefix, e.Name())); err != nil {
+					return err
+				} else {
+					defer func() {
+						if f.Close() != nil {
+							// unreachable
+							panic("foreign state file closed prematurely")
+						}
+					}()
+
+					var s launcherState
+					r = append(r, &s)
+					return gob.NewDecoder(f).Decode(&s)
+				}
+			}(); err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	return r, nil
+}
+
+func beforeExit() {
+	if err := os.Remove(statePath); err != nil && !errors.Is(err, fs.ErrNotExist) {
+		fmt.Println("Error removing state file:", err)
+	}
+
+	if a, err := readLaunchers(); err != nil {
+		fmt.Println("Error reading active launchers:", err)
+		os.Exit(1)
+	} else if len(a) > 0 {
+		// other launchers are still active
+		if verbose {
+			fmt.Printf("Found %d active launchers, exiting without cleaning up\n", len(a))
+		}
+		return
+	}
+
+	if verbose {
+		fmt.Println("No other launchers active, will clean up")
+	}
+
+	if xcbActionComplete {
+		if verbose {
+			fmt.Printf("X11: Removing XHost entry SI:localuser:%s\n", ego.Username)
+		}
+		if err := changeHosts(xcbHostModeDelete, xcbFamilyServerInterpreted, "localuser\x00"+ego.Username); err != nil {
+			fmt.Println("Error removing XHost entry:", err)
+		}
+	}
+
+	for _, candidate := range cleanupCandidate {
+		if err := aclUpdatePerm(candidate, uid); err != nil {
+			fmt.Printf("Error stripping ACL entry from '%s': %s\n", candidate, err)
+		}
+		if verbose {
+			fmt.Printf("Stripped ACL entry for user '%s' from '%s'\n", ego.Username, candidate)
+		}
+	}
+}
+
+func fatal(msg ...any) {
+	fmt.Println(msg...)
+	beforeExit()
+	os.Exit(1)
+}