fixed parsing /proc/$pid/stat starttime field

On systems that have been running for a long time (for example 552
days) we were failing parsing the starttime field:

```
Could not find or convert Starttime. This should never happen.
Please report this incident to the Opensnitch developers:
strconv.Atoi: parsing "4242026842": value out of range
```

- extra: fixed tests.

daemon/procmon/activepids.go

@@ -15,11 +15,11 @@ type value struct {
 	Process *Process
 	//Starttime uniquely identifies a process, it is the 22nd value in /proc/<PID>/stat
 	//if another process starts with the same PID, it's Starttime will be unique
-	Starttime uint32
+	Starttime uint64
 }
 
 var (
-	activePids     = make(map[uint32]value)
+	activePids     = make(map[uint64]value)
 	activePidsLock = sync.RWMutex{}
 )
 
@@ -38,14 +38,14 @@ func MonitorActivePids() {
 				deleteProcEntry(int(k))
 				continue
 			}
-			startTime, err := strconv.Atoi(strings.Split(string(data), " ")[21])
+			startTime, err := strconv.ParseInt(strings.Split(string(data), " ")[21], 10, 64)
 			if err != nil {
-				log.Error("Could not find or convert Starttime. This should never happen. Please report this incident to the Opensnitch developers.")
+				log.Error("Could not find or convert Starttime. This should never happen. Please report this incident to the Opensnitch developers: %v", err)
 				delete(activePids, k)
 				deleteProcEntry(int(k))
 				continue
 			}
-			if uint32(startTime) != v.Starttime {
+			if uint64(startTime) != v.Starttime {
 				//extremely unlikely: the original process has quit and another process
 				//was started with the same PID - all this in less than 1 second
 				log.Error("Same PID but different Starttime. Please report this incident to the Opensnitch developers.")
@@ -58,7 +58,7 @@ func MonitorActivePids() {
 	}
 }
 
-func findProcessInActivePidsCache(pid uint32) *Process {
+func findProcessInActivePidsCache(pid uint64) *Process {
 	activePidsLock.Lock()
 	defer activePidsLock.Unlock()
 	if value, ok := activePids[pid]; ok {
@@ -67,23 +67,23 @@ func findProcessInActivePidsCache(pid uint32) *Process {
 	return nil
 }
 
-func addToActivePidsCache(pid uint32, proc *Process) {
+func addToActivePidsCache(pid uint64, proc *Process) {
 
 	data, err := ioutil.ReadFile(fmt.Sprintf("/proc/%d/stat", pid))
 	if err != nil {
 		//most likely the process has quit by now
 		return
 	}
-	startTime, err2 := strconv.Atoi(strings.Split(string(data), " ")[21])
+	startTime, err2 := strconv.ParseInt(strings.Split(string(data), " ")[21], 10, 64)
 	if err2 != nil {
-		log.Error("Could not find or convert Starttime. This should never happen. Please report this incident to the Opensnitch developers.")
+		log.Error("Could not find or convert Starttime. This should never happen. Please report this incident to the Opensnitch developers: %v", err)
 		return
 	}
 
 	activePidsLock.Lock()
 	activePids[pid] = value{
 		Process:   proc,
-		Starttime: uint32(startTime),
+		Starttime: uint64(startTime),
 	}
 	activePidsLock.Unlock()
 }

daemon/procmon/activepids_test.go

@@ -28,7 +28,7 @@ func TestMonitorActivePids(t *testing.T) {
 	fmt.Println("tmp dir", tmpDir)
 	defer os.RemoveAll(tmpDir)
 
-	go monitorActivePids()
+	go MonitorActivePids()
 
 	//build a "helper binary" with "go test -c -o /tmp/path" and put it into a tmp dir
 	helperBinaryPath := tmpDir + "/helper1"
@@ -58,7 +58,7 @@ func TestMonitorActivePids(t *testing.T) {
 		pid := helperCmd.Process.Pid
 		proc := NewProcess(pid, helperBinaryPath)
 		helperProcs = append(helperProcs, proc)
-		addToActivePidsCache(uint32(pid), proc)
+		addToActivePidsCache(uint64(pid), proc)
 	}
 	//sleep to make sure all processes started before we proceed
 	time.Sleep(time.Second * 1)
@@ -66,7 +66,7 @@ func TestMonitorActivePids(t *testing.T) {
 	for i := 0; i < numberOfHelpers; i++ {
 		proc := helperProcs[i]
 		pid := proc.ID
-		foundProc := findProcessInActivePidsCache(uint32(pid))
+		foundProc := findProcessInActivePidsCache(uint64(pid))
 		if foundProc == nil {
 			t.Error("PID not found among active processes", pid)
 		}
@@ -84,7 +84,7 @@ func TestMonitorActivePids(t *testing.T) {
 	time.Sleep(time.Second * 1)
 
 	//make sure only the alive process is in the cache
-	foundProc := findProcessInActivePidsCache(uint32(helperProcs[numberOfHelpers-1].ID))
+	foundProc := findProcessInActivePidsCache(uint64(helperProcs[numberOfHelpers-1].ID))
 	if foundProc == nil {
 		t.Error("last alive PID is not found among active processes", foundProc)
 	}

daemon/procmon/parse.go

@@ -92,7 +92,7 @@ func FindProcess(pid int, interceptUnknown bool) *Process {
 		return NewProcess(0, "")
 	}
 
-	if proc := findProcessInActivePidsCache(uint32(pid)); proc != nil {
+	if proc := findProcessInActivePidsCache(uint64(pid)); proc != nil {
 		return proc
 	}
 
@@ -110,7 +110,7 @@ func FindProcess(pid int, interceptUnknown bool) *Process {
 			proc.readEnv()
 			proc.cleanPath()
 
-			addToActivePidsCache(uint32(pid), proc)
+			addToActivePidsCache(uint64(pid), proc)
 			return proc
 		}
 	}
@@ -128,7 +128,7 @@ func FindProcess(pid int, interceptUnknown bool) *Process {
 		proc.readEnv()
 		proc.cleanPath()
 
-		addToActivePidsCache(uint32(pid), proc)
+		addToActivePidsCache(uint64(pid), proc)
 		return proc
 	}
 	return nil