eventloop: reuse comm resolver for pid seeding (task 317)

2 files changed, 52 insertions, 13 deletions

diff --git a/internal/eventloop.go b/internal/eventloop.go
index e034c31..29e0918 100644
--- a/internal/eventloop.go
+++ b/internal/eventloop.go
@@ -65,19 +65,7 @@ func (e *eventLoop) seedTrackedPidComm() {
 	if pid <= 0 {
 		return
 	}
-	commPath := fmt.Sprintf("/proc/%d/comm", pid)
-	data, err := os.ReadFile(commPath)
-	if err != nil {
-		return
-	}
-	comm := string(data)
-	if len(comm) > 0 && comm[len(comm)-1] == '\n' {
-		comm = comm[:len(comm)-1]
-	}
-	if comm == "" {
-		return
-	}
-	e.comms[uint32(pid)] = comm
+	_ = e.comm(uint32(pid))
 }
 
 func (e *eventLoop) stats() string {
diff --git a/internal/eventloop_seed_test.go b/internal/eventloop_seed_test.go
new file mode 100644
index 0000000..f8e631a
--- /dev/null
+++ b/internal/eventloop_seed_test.go
@@ -0,0 +1,51 @@
+package internal
+
+import (
+	"os"
+	"testing"
+
+	"ior/internal/flags"
+)
+
+func TestSeedTrackedPidCommCachesTrackedPidComm(t *testing.T) {
+	oldPID := flags.Get().PidFilter
+	flags.SetPidFilter(os.Getpid())
+	t.Cleanup(func() {
+		flags.SetPidFilter(oldPID)
+	})
+
+	el := &eventLoop{
+		comms: make(map[uint32]string),
+	}
+
+	pid := uint32(os.Getpid())
+	want := el.comm(pid)
+	if want == "" {
+		t.Fatalf("expected comm for pid %d", pid)
+	}
+	delete(el.comms, pid)
+
+	el.seedTrackedPidComm()
+
+	if got := el.comms[pid]; got != want {
+		t.Fatalf("seeded comm = %q, want %q", got, want)
+	}
+}
+
+func TestSeedTrackedPidCommSkipsWhenPidFilterDisabled(t *testing.T) {
+	oldPID := flags.Get().PidFilter
+	flags.SetPidFilter(-1)
+	t.Cleanup(func() {
+		flags.SetPidFilter(oldPID)
+	})
+
+	el := &eventLoop{
+		comms: make(map[uint32]string),
+	}
+
+	el.seedTrackedPidComm()
+
+	if len(el.comms) != 0 {
+		t.Fatalf("expected no comms to be seeded when pid filter is disabled")
+	}
+}