Merge pull request nightlyone#12 from stewi1014/master

Added relevant and go-compatable tests to testing file. Fixed dead PID on windows.

Author: nightlyone

lockfile.go

@@ -44,11 +44,21 @@ func (l Lockfile) GetOwner() (*os.Process, error) {
 
 	// try hard for pids. If no pid, the lockfile is junk anyway and we delete it.
 	if pid > 0 {
-		p, err := os.FindProcess(pid)
+		running, err := isRunning(pid)
 		if err != nil {
 			return nil, err
 		}
-		return p, isProcessAlive(p)
+
+		if running {
+			proc, err := os.FindProcess(pid)
+			if err != nil {
+				return nil, err
+			}
+			return proc, nil
+		} else {
+			return nil, ErrDeadOwner
+		}
+
 	} else {
 		return nil, ErrInvalidPid
 	}

lockfile_test.go

@@ -1,14 +1,17 @@
-package lockfile_test
+package lockfile
 
 import (
-	lockfile "."
 	"fmt"
+	"io/ioutil"
+	"math/rand"
 	"os"
 	"path/filepath"
+	"strconv"
+	"testing"
 )
 
 func ExampleLockfile() {
-	lock, err := lockfile.New(filepath.Join(os.TempDir(), "lock.me.now.lck"))
+	lock, err := New(filepath.Join(os.TempDir(), "lock.me.now.lck"))
 	if err != nil {
 		fmt.Printf("Cannot init lock. reason: %v\n", err)
 		panic(err)
@@ -26,3 +29,105 @@ func ExampleLockfile() {
 	fmt.Println("Do stuff under lock")
 	// Output: Do stuff under lock
 }
+
+func TestLock(t *testing.T) {
+	path, err := filepath.Abs("test_lockfile.pid")
+	if err != nil {
+		panic(err)
+	}
+
+	lf, err := New(path)
+	if err != nil {
+		t.Fail()
+		fmt.Println("Error making lockfile: ", err)
+		return
+	}
+
+	err = lf.TryLock()
+	if err != nil {
+		t.Fail()
+		fmt.Println("Error locking lockfile: ", err)
+		return
+	}
+
+	err = lf.Unlock()
+	if err != nil {
+		t.Fail()
+		fmt.Println("Error unlocking lockfile: ", err)
+		return
+	}
+}
+
+func TestDeadPID(t *testing.T) {
+	path, err := filepath.Abs("test_lockfile.pid")
+	if err != nil {
+		panic(err)
+	}
+
+	pid := GetDeadPID()
+
+	ioutil.WriteFile(path, []byte(strconv.Itoa(pid)+"\n"), 0666)
+}
+
+func GetDeadPID() int {
+	for {
+		pid := rand.Int() % 4096 //I have no idea how windows handles large PIDs, or if they even exist. Limit it to 4096 to be safe.
+		running, err := isRunning(pid)
+		if err != nil {
+			fmt.Println("Error checking PID: ", err)
+			continue
+		}
+
+		if !running {
+			return pid
+		}
+	}
+}
+
+func TestBusy(t *testing.T) {
+	path, err := filepath.Abs("test_lockfile.pid")
+	if err != nil {
+		t.Fail()
+		fmt.Println(err)
+		return
+	}
+
+	lf1, err := New(path)
+	if err != nil {
+		t.Fail()
+		fmt.Println(err)
+		return
+	}
+
+	err = lf1.TryLock()
+	if err != nil {
+		t.Fail()
+		fmt.Println(err)
+		return
+	}
+
+	lf2, err := New(path)
+	if err != nil {
+		t.Fail()
+		fmt.Println(err)
+		return
+	}
+
+	err = lf2.TryLock()
+	if err == nil {
+		t.Fail()
+		fmt.Println("No error locking already locked lockfile!")
+		return
+	} else if err != ErrBusy {
+		t.Fail()
+		fmt.Println(err)
+		return
+	}
+
+	err = lf1.Unlock()
+	if err != nil {
+		t.Fail()
+		fmt.Println(err)
+		return
+	}
+}

lockfile_unix.go

@@ -7,22 +7,16 @@ import (
 	"syscall"
 )
 
-func isProcessAlive(p *os.Process) error {
-	err := p.Signal(os.Signal(syscall.Signal(0)))
-	if err == nil {
-		return nil
-	}
-	errno, ok := err.(syscall.Errno)
-	if !ok {
-		return ErrDeadOwner
-	}
-
-	switch errno {
-	case syscall.ESRCH:
-		return ErrDeadOwner
-	case syscall.EPERM:
-		return nil
-	default:
-		return err
+func isRunning(pid int) (bool, error) {
+	proc, err := os.FindProcess(pid)
+	if err != nil {
+		return false, err
+	} else {
+		err := proc.Signal(syscall.Signal(0))
+		if err == nil {
+			return true, nil
+		} else {
+			return false, nil
+		}
 	}
 }

lockfile_windows.go

@@ -1,32 +1,30 @@
 package lockfile
 
 import (
-	"os"
-	"reflect"
 	"syscall"
 )
 
-func isProcessAlive(p *os.Process) error {
-	// Extract handle value from the os.Process struct to avoid the need
-	// of a second, manually opened process handle.
-	value := reflect.ValueOf(p)
-	// Dereference *os.Process to os.Process
-	value = value.Elem()
-	field := value.FieldByName("handle")
-
-	handle := syscall.Handle(field.Uint())
+//For some reason these consts don't exist in syscall.
+const (
+	error_invalid_parameter = 87
+	code_still_active       = 259
+)
 
-	var code uint32
-	err := syscall.GetExitCodeProcess(handle, &code)
+func isRunning(pid int) (bool, error) {
+	procHnd, err := syscall.OpenProcess(syscall.PROCESS_QUERY_INFORMATION, true, uint32(pid))
 	if err != nil {
-		return err
+		if scerr, ok := err.(syscall.Errno); ok {
+			if uintptr(scerr) == error_invalid_parameter {
+				return false, nil
+			}
+		}
 	}
 
-	// code will contain the exit code of the process or 259 (STILL_ALIVE)
-	// if the process has not exited yet.
-	if code == 259 {
-		return nil
+	var code uint32
+	err = syscall.GetExitCodeProcess(procHnd, &code)
+	if err != nil {
+		return false, err
 	}
 
-	return ErrDeadOwner
+	return code == code_still_active, nil
 }