Wait quietly for clipmenud's session lock; count the operator's clipmenud (issues 860, 862)

This commit is contained in:
2026-10-15 23:15:35 +02:00
parent c9848f4fb8
commit cf304d8629
4 changed files with 125 additions and 4 deletions
@@ -5,6 +5,7 @@ import (
"errors"
"os"
"os/exec"
"os/user"
"path/filepath"
"strconv"
"strings"
@@ -225,3 +226,27 @@ func TestWithoutAStoreTheChangesSayWhy(t *testing.T) {
t.Fatalf("an empty history: %+v, %v", h, err)
}
}
// The tools can run as another account than the operator's; the daemon that counts is the operator's
// (issue 860). Here the operator is the test's own account and the tool runs as a different uid.
func TestCollectingIsTheOperatorsDaemonNotThatOfTheAccountTheToolRunsAs(t *testing.T) {
store(t, map[string]string{"first": "first"}, "first")
fakeProcess(t, nobody, "clipmenud") // owned by the test's uid: the operator's
u, err := user.Current()
if err != nil {
t.Skip(err)
}
t.Setenv("MESH_OPERATOR_ACCOUNT", u.Username)
old := toolUID
toolUID = func() int { return os.Getuid() + 1 }
t.Cleanup(func() { toolUID = old })
h, err := History(10)
if err != nil || !h.Collecting {
t.Fatalf("the operator's clipmenud runs: %+v %v", h, err)
}
// without the operator named, the tool's own uid stands, and that account has no daemon
t.Setenv("MESH_OPERATOR_ACCOUNT", "")
if h, _ := History(10); h.Collecting {
t.Fatalf("another account's daemon counted: %+v", h)
}
}
@@ -7,6 +7,8 @@ import (
"os/exec"
"reflect"
"strings"
"sync"
"syscall"
"testing"
"time"
)
@@ -145,3 +147,78 @@ func TestTheLauncherUsesTheManagersDisplayAndWaitsOtherwise(t *testing.T) {
t.Fatalf("the display that arrived while waiting: %q %v", out, ok)
}
}
// Run for real: while another clipmenud of the account holds the session lock the launcher waits without
// a word, and starts clipmenud once the lock is free (issue 862).
func TestTheLauncherWaitsQuietlyWhileAnotherClipmenudHoldsTheLock(t *testing.T) {
if _, err := exec.LookPath("flock"); err != nil {
t.Skip("flock is missing here")
}
m := readManifest(t)
script, _ := m.resource(t, "launcher")["content"].(string)
dir := t.TempDir()
body := strings.Replace(script, "exec clipmenud", `echo "started"`, 1)
file := dir + "/launcher"
if err := os.WriteFile(file, []byte(body), 0o755); err != nil {
t.Fatal(err)
}
store := dir + "/cm/clipmenu.6.op"
os.MkdirAll(store, 0o700)
lock := store + "/session_lock"
// the older clipmenud: it holds the lock the way clipmenud does, until it is killed
holder := exec.Command("flock", "-x", "-n", lock, "sleep", "60")
holder.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
if err := holder.Start(); err != nil {
t.Fatal(err)
}
// flock's child shares the lock, so the whole group goes
release := func() { syscall.Kill(-holder.Process.Pid, syscall.SIGKILL); holder.Wait() }
defer release()
for i := 0; i < 50; i++ {
if probe := exec.Command("flock", "-n", lock, "true"); probe.Run() != nil {
break
}
time.Sleep(50 * time.Millisecond)
}
var out syncBuffer
cmd := exec.Command("sh", file)
cmd.Env = []string{"PATH=" + os.Getenv("PATH"), "HOME=" + dir, "DISPLAY=:7", "USER=op", "CM_DIR=" + dir + "/cm"}
cmd.Stdout, cmd.Stderr = &out, &out
if err := cmd.Start(); err != nil {
t.Fatal(err)
}
done := make(chan error, 1)
go func() { done <- cmd.Wait() }()
select {
case <-done:
t.Fatalf("the launcher went on while the lock was held: %q", out.String())
case <-time.After(2500 * time.Millisecond):
}
if out.Len() != 0 {
t.Fatalf("the launcher spoke while it waited: %q", out.String())
}
release()
select {
case <-done:
case <-time.After(5 * time.Second):
cmd.Process.Kill()
t.Fatal("the launcher did not start clipmenud after the lock was freed")
}
if got := strings.TrimSpace(out.String()); got != "started" {
t.Fatalf("after the lock was freed: %q", got)
}
}
type syncBuffer struct {
mu sync.Mutex
b strings.Builder
}
func (s *syncBuffer) Write(p []byte) (int, error) {
s.mu.Lock()
defer s.mu.Unlock()
return s.b.Write(p)
}
func (s *syncBuffer) Len() int { s.mu.Lock(); defer s.mu.Unlock(); return s.b.Len() }
func (s *syncBuffer) String() string { s.mu.Lock(); defer s.mu.Unlock(); return s.b.String() }
+22 -3
View File
@@ -21,6 +21,7 @@ import (
"fmt"
"os"
"os/exec"
"os/user"
"path/filepath"
"sort"
"strconv"
@@ -386,13 +387,31 @@ func (c *capped) Write(p []byte) (int, error) {
return c.Buffer.Write(p)
}
// processesOf are the pids of this uid's processes whose command name is comm, oldest first.
// toolUID is the uid the tool runs as; a test replaces it to stand for a tool that runs as another
// account than the operator's.
var toolUID = os.Getuid
// operatorUID is the uid of the operator's account, whose clipmenud and store these tools look at.
// The runtime serves the tools as an account that need not be the operator's and names the operator
// in MESH_OPERATOR_ACCOUNT; without it (or when it is unknown here) the tool's own uid stands.
func operatorUID() int {
if name := strings.TrimSpace(os.Getenv("MESH_OPERATOR_ACCOUNT")); name != "" {
if u, err := user.Lookup(name); err == nil {
if id, err := strconv.Atoi(u.Uid); err == nil {
return id
}
}
}
return toolUID()
}
// processesOf are the pids of the operator account's processes whose command name is comm, oldest first.
func processesOf(comm string) []int {
entries, err := os.ReadDir(procRoot)
if err != nil {
return nil
}
uid := os.Getuid()
uid := operatorUID()
var pids []int
for _, e := range entries {
pid, err := strconv.Atoi(e.Name())
@@ -411,7 +430,7 @@ func processesOf(comm string) []int {
return pids
}
// signalAll sends sig to every process of this uid named comm, and answers the pids it reached.
// signalAll sends sig to every process of the operator account named comm, and answers the pids it reached.
func signalAll(comm string, sig syscall.Signal) []int {
var reached []int
for _, pid := range processesOf(comm) {
+1 -1
View File
@@ -75,7 +75,7 @@
"type": "file",
"path": "/usr/local/lib/mesh-clipmenu/clipmenud-session",
"mode": "0755",
"content": "#!/bin/sh\n# clipmenud as the operator's user unit starts it, written by the mesh (module clipmenu). Replaced at every push.\n#\n# The account's service manager starts before the X server does, and has a DISPLAY only once the session's\n# xinitrc has handed it over (module xorg). So this waits, quietly, until the display is known, and exits\n# only when the session ends with it: a quick exit would run the unit into its start limit. DISPLAY, when\n# the manager has it, wins. Without it, exactly one X socket names the display; none or several (a\n# second server beside the session) wait for the session's own to arrive.\n# A running process does not see what the session hands the manager later, so each pass asks the manager.\nuntil [ -n \"$DISPLAY\" ]; do\n\tfor pair in $(systemctl --user show-environment 2>/dev/null | grep -E '^(DISPLAY|XAUTHORITY)='); do\n\t\texport \"$pair\"\n\tdone\n\t[ -n \"$DISPLAY\" ] && break\n\tset -- /tmp/.X11-unix/X*\n\tif [ $# -eq 1 ] && [ -S \"$1\" ]; then\n\t\tDISPLAY=\":${1##*/X}\"\n\t\texport DISPLAY\n\telse\n\t\tsleep 1\n\tfi\ndone\nif [ -z \"$XAUTHORITY\" ] && [ -r \"$HOME/.Xauthority\" ]; then\n\tXAUTHORITY=\"$HOME/.Xauthority\"\n\texport XAUTHORITY\nfi\nPATH=\"/usr/local/lib/mesh-clipmenu:$PATH\"\nexport PATH\nexec clipmenud\n"
"content": "#!/bin/sh\n# clipmenud as the operator's user unit starts it, written by the mesh (module clipmenu). Replaced at every push.\n#\n# The account's service manager starts before the X server does, and has a DISPLAY only once the session's\n# xinitrc has handed it over (module xorg). So this waits, quietly, until the display is known, and exits\n# only when the session ends with it: a quick exit would run the unit into its start limit. DISPLAY, when\n# the manager has it, wins. Without it, exactly one X socket names the display; none or several (a\n# second server beside the session) wait for the session's own to arrive.\n# A running process does not see what the session hands the manager later, so each pass asks the manager.\nuntil [ -n \"$DISPLAY\" ]; do\n\tfor pair in $(systemctl --user show-environment 2>/dev/null | grep -E '^(DISPLAY|XAUTHORITY)='); do\n\t\texport \"$pair\"\n\tdone\n\t[ -n \"$DISPLAY\" ] && break\n\tset -- /tmp/.X11-unix/X*\n\tif [ $# -eq 1 ] && [ -S \"$1\" ]; then\n\t\tDISPLAY=\":${1##*/X}\"\n\t\texport DISPLAY\n\telse\n\t\tsleep 1\n\tfi\ndone\nif [ -z \"$XAUTHORITY\" ] && [ -r \"$HOME/.Xauthority\" ]; then\n\tXAUTHORITY=\"$HOME/.Xauthority\"\n\texport XAUTHORITY\nfi\n# clipmenud allows one daemon per account: it takes an exclusive flock on its session_lock file and exits\n# with status 2 when that is held. After a delivery without a new login, the session's older clipmenud (from\n# its xinitrc) still holds it, and a start would run the unit round its restart loop. So this waits, quietly,\n# until the lock is free: it looks at the same file clipmenud locks (the directory is clipmenud's own rule)\n# and lets go at once. Exit status 75 is only \"held\"; any other outcome starts clipmenud, which says its own\n# error. Another daemon winning the gap between look and start costs one restart, not a loop.\nlock=\"${CM_DIR:-${XDG_RUNTIME_DIR-${TMPDIR-/tmp}}}/clipmenu.6.$USER/session_lock\"\nwhile [ -e \"$lock\" ]; do\n\tflock -n -E 75 \"$lock\" true\n\t[ $? -eq 75 ] || break\n\tsleep 2\ndone\nPATH=\"/usr/local/lib/mesh-clipmenu:$PATH\"\nexport PATH\nexec clipmenud\n"
},
{
"id": "daemon",