Fix cross platform build with locking

Author: tizbac

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/getlantern/systray v1.2.2
 	github.com/jeromehadorn/vss v0.1.0
 	github.com/klauspost/compress v1.17.4
+	github.com/rodolfoag/gow32 v0.0.0-20230512144032-1e896a3c51aa
 	github.com/tawesoft/golib/v2 v2.10.0
 	golang.org/x/net v0.19.0
 )
@@ -27,7 +28,6 @@ require (
 	github.com/godbus/dbus/v5 v5.1.0 // indirect
 	github.com/nu7hatch/gouuid v0.0.0-20131221200532-179d4d0c4d8d // indirect
 	github.com/oxtoacart/bpool v0.0.0-20190530202638-03653db5a59c // indirect
-	github.com/rodolfoag/gow32 v0.0.0-20230512144032-1e896a3c51aa // indirect
 	github.com/tadvi/systray v0.0.0-20190226123456-11a2b8fa57af // indirect
 	golang.org/x/exp v0.0.0-20221208152030-732eee02a75a // indirect
 	golang.org/x/sys v0.15.0 // indirect

main.go

@@ -11,17 +11,15 @@ import (
 	"os"
 	"runtime"
 	"sync/atomic"
-	"syscall"
 	"time"
 
 	"github.com/cornelk/hashmap"
 	"github.com/gen2brain/beeep"
 	"github.com/getlantern/systray"
 	"github.com/tawesoft/golib/v2/dialog"
-	"github.com/rodolfoag/gow32"
 )
 
-const MutexName = "proxmoxbackupclient_go"
+
 
 var defaultMailSubjectTemplate = "Backup {{.Status}}"
 var defaultMailBodyTemplate = `{{if .Success}}Backup complete ({{.FromattedDuration}})
@@ -78,27 +76,26 @@ func main() {
 		os.Exit(1)
 	}
 
-	if runtime.GOOS == "windows" {
-		mutexid, err := gow32.CreateMutex(MutexName)
-		if (err != nil) {
-			if exitcode := int(err.(syscall.Errno)); exitcode == gow32.ERROR_ALREADY_EXISTS {
-				dialog.Error("Backup jobs need to run exclusively, please wait until the previous job has finished")
-				os.Exit(2)
-			}
-			// this should never happen
-			panic(err)
-		}
-		defer gow32.ReleaseMutex(mutexid)
+	L := Locking{}
 
-		go systray.Run(func() {
-			systray.SetIcon(ICON)
-			systray.SetTooltip("PBSGO Backup running")
-			beeep.Notify("Proxmox Backup Go", "Backup started", "")
-		},
-			func() {
-
-			})
+	
+	lock_ok := L.AcquireProcessLock()
+	if !lock_ok {
+		
+		dialog.Error("Backup jobs need to run exclusively, please wait until the previous job has finished")
+		os.Exit(2)
 	}
+	defer L.ReleaseProcessLock()
+
+	go systray.Run(func() {
+		systray.SetIcon(ICON)
+		systray.SetTooltip("PBSGO Backup running")
+		beeep.Notify("Proxmox Backup Go", "Backup started", "")
+	},
+		func() {
+
+		})
+	
 
 	insecure := cfg.CertFingerprint != ""
 

stub_locking.go

@@ -0,0 +1,14 @@
+// +build linux darwin freebsd openbsd
+package main
+
+type Locking struct {
+	mutexid uintptr
+}
+
+func (l *Locking) AcquireProcessLock() bool {
+	return true
+}
+
+func (l * Locking) ReleaseProcessLock() {
+	
+}

win_locking.go

@@ -0,0 +1,29 @@
+//go:build windows
+// +build windows
+package main
+
+import "github.com/rodolfoag/gow32"
+import "syscall"
+
+const MutexName = "proxmoxbackupclient_go"
+
+
+type Locking struct {
+	mutexid uintptr
+}
+
+func (l *Locking) AcquireProcessLock() bool {
+	mutexid , err := gow32.CreateMutex(MutexName)
+	if err != nil {
+		if exitcode := int(err.(syscall.Errno)); exitcode == gow32.ERROR_ALREADY_EXISTS {
+			return false 
+		}
+		panic(err)
+	}
+	l.mutexid = mutexid
+	return true
+}
+
+func (l * Locking) ReleaseProcessLock() {
+	gow32.ReleaseMutex(l.mutexid)
+}