syz-manager: add pause function

The pause function is useful to make manager stop consuming CPU
for some time, e.g. when it runs on a shared machine,
and a user wants to use CPU for something else.
Previously one would need to kill the manager process and
restart later to achieve this, but the restart is costly,
and aborts all bug reproductions.

1 files changed, 21 insertions, 7 deletions

diff --git a/pkg/manager/http.go b/pkg/manager/http.go
index 06fa9ca2b..05972ba3d 100644
--- a/pkg/manager/http.go
+++ b/pkg/manager/http.go
@@ -46,13 +46,14 @@ type CoverageInfo struct {
 
 type HTTPServer struct {
 	// To be set before calling Serve.
-	Cfg        *mgrconfig.Config
-	StartTime  time.Time
-	CrashStore *CrashStore
-	DiffStore  *DiffFuzzerStore
-	ReproLoop  *ReproLoop
-	Pool       *vm.Dispatcher
-	Pools      map[string]*vm.Dispatcher
+	Cfg         *mgrconfig.Config
+	StartTime   time.Time
+	CrashStore  *CrashStore
+	DiffStore   *DiffFuzzerStore
+	ReproLoop   *ReproLoop
+	Pool        *vm.Dispatcher
+	Pools       map[string]*vm.Dispatcher
+	TogglePause func(paused bool)
 
 	// Can be set dynamically after calling Serve.
 	Corpus          atomic.Pointer[corpus.Corpus]
@@ -62,6 +63,7 @@ type HTTPServer struct {
 
 	// Internal state.
 	expertMode bool
+	paused     bool
 }
 
 func (serv *HTTPServer) Serve() {
@@ -113,6 +115,13 @@ func (serv *HTTPServer) httpAction(w http.ResponseWriter, r *http.Request) {
 	switch r.FormValue("action") {
 	case "toggle-expert":
 		serv.expertMode = !serv.expertMode
+	case "pause-unpause":
+		if serv.TogglePause == nil {
+			http.Error(w, "pause is not implemented", http.StatusNotImplemented)
+			return
+		}
+		serv.paused = !serv.paused
+		serv.TogglePause(serv.paused)
 	}
 	http.Redirect(w, r, r.FormValue("url"), http.StatusFound)
 }
@@ -960,6 +969,7 @@ type UIPageHeader struct {
 	GitRevision     string
 	GitRevisionLink string
 	ExpertMode      bool
+	Paused          bool
 }
 
 func (serv *HTTPServer) pageHeader(r *http.Request, title string) UIPageHeader {
@@ -979,6 +989,7 @@ func (serv *HTTPServer) pageHeader(r *http.Request, title string) UIPageHeader {
 		GitRevision:     revision,
 		GitRevisionLink: revisionLink,
 		ExpertMode:      serv.expertMode,
+		Paused:          serv.paused,
 	}
 }
 
@@ -1003,6 +1014,9 @@ func createPage(data any, body string) *template.Template {
 						<button type="submit" name="action" value="toggle-expert" class="action_button{{if .ExpertMode}}_selected{{end}}" title="Toggle expert mode">
 							🧠
 						</input>
+						<button type="submit" name="action" value="pause-unpause" class="action_button{{if .Paused}}_selected{{end}}" title="Pause/unpause fuzzing">
+							{{if .Paused}}▶️{{else}}⏸️{{end}}
+						</input>
 					</form>
 				</td>
 				<td class="search">