From e795f75bbb399c3b211a6b3b03e1da243d7e63da Mon Sep 17 00:00:00 2001
From: Mike Sawka <mike@commandline.dev>
Date: Fri, 4 Oct 2024 12:20:52 -0700
Subject: [PATCH] only use filemutex for windows (#960)

---
 cmd/server/main-server.go      |  2 +-
 go.mod                         |  2 +-
 pkg/wavebase/wavebase-posix.go | 30 ++++++++++++++++++++++++++++++
 pkg/wavebase/wavebase-win.go   | 29 +++++++++++++++++++++++++++++
 pkg/wavebase/wavebase.go       | 19 ++++---------------
 5 files changed, 65 insertions(+), 17 deletions(-)
 create mode 100644 pkg/wavebase/wavebase-posix.go
 create mode 100644 pkg/wavebase/wavebase-win.go

diff --git a/cmd/server/main-server.go b/cmd/server/main-server.go
index 6a6d441ba..8b3e2dc83 100644
--- a/cmd/server/main-server.go
+++ b/cmd/server/main-server.go
@@ -202,7 +202,7 @@ func main() {
 		return
 	}
 	defer func() {
-		err = waveLock.Unlock()
+		err = waveLock.Close()
 		if err != nil {
 			log.Printf("error releasing wave lock: %v\n", err)
 		}
diff --git a/go.mod b/go.mod
index 26ed5e328..9f4774c85 100644
--- a/go.mod
+++ b/go.mod
@@ -23,6 +23,7 @@ require (
 	github.com/spf13/cobra v1.8.1
 	github.com/wavetermdev/htmltoken v0.1.0
 	golang.org/x/crypto v0.28.0
+	golang.org/x/sys v0.26.0
 	golang.org/x/term v0.25.0
 )
 
@@ -41,7 +42,6 @@ require (
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
 	go.uber.org/atomic v1.7.0 // indirect
 	golang.org/x/net v0.29.0 // indirect
-	golang.org/x/sys v0.26.0 // indirect
 )
 
 replace github.com/kevinburke/ssh_config => github.com/wavetermdev/ssh_config v0.0.0-20240306041034-17e2087ebde2
diff --git a/pkg/wavebase/wavebase-posix.go b/pkg/wavebase/wavebase-posix.go
new file mode 100644
index 000000000..352302221
--- /dev/null
+++ b/pkg/wavebase/wavebase-posix.go
@@ -0,0 +1,30 @@
+// Copyright 2024, Command Line Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build !windows
+
+package wavebase
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+
+	"golang.org/x/sys/unix"
+)
+
+func AcquireWaveLock() (FDLock, error) {
+	homeDir := GetWaveHomeDir()
+	lockFileName := filepath.Join(homeDir, WaveLockFile)
+	log.Printf("[base] acquiring lock on %s\n", lockFileName)
+	fd, err := os.OpenFile(lockFileName, os.O_RDWR|os.O_CREATE, 0600)
+	if err != nil {
+		return nil, err
+	}
+	err = unix.Flock(int(fd.Fd()), unix.LOCK_EX|unix.LOCK_NB)
+	if err != nil {
+		fd.Close()
+		return nil, err
+	}
+	return fd, nil
+}
diff --git a/pkg/wavebase/wavebase-win.go b/pkg/wavebase/wavebase-win.go
new file mode 100644
index 000000000..a22ac2f85
--- /dev/null
+++ b/pkg/wavebase/wavebase-win.go
@@ -0,0 +1,29 @@
+// Copyright 2024, Command Line Inc.
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build windows
+
+package wavebase
+
+import (
+	"fmt"
+	"log"
+	"path/filepath"
+
+	"github.com/alexflint/go-filemutex"
+)
+
+func AcquireWaveLock() (FDLock, error) {
+	homeDir := GetWaveHomeDir()
+	lockFileName := filepath.Join(homeDir, WaveLockFile)
+	log.Printf("[base] acquiring lock on %s\n", lockFileName)
+	m, err := filemutex.New(lockFileName)
+	if err != nil {
+		return nil, fmt.Errorf("filemutex new error: %w", err)
+	}
+	err = m.TryLock()
+	if err != nil {
+		return nil, fmt.Errorf("filemutex trylock error: %w", err)
+	}
+	return m, nil
+}
diff --git a/pkg/wavebase/wavebase.go b/pkg/wavebase/wavebase.go
index a4c366919..fd0cb5738 100644
--- a/pkg/wavebase/wavebase.go
+++ b/pkg/wavebase/wavebase.go
@@ -17,8 +17,6 @@ import (
 	"strings"
 	"sync"
 	"time"
-
-	"github.com/alexflint/go-filemutex"
 )
 
 // set by main-server.go
@@ -41,6 +39,10 @@ const AppPathBinDir = "bin"
 var baseLock = &sync.Mutex{}
 var ensureDirCache = map[string]bool{}
 
+type FDLock interface {
+	Close() error
+}
+
 func IsDevMode() bool {
 	pdev := os.Getenv(WaveDevVarName)
 	return pdev != ""
@@ -200,19 +202,6 @@ func DetermineLocale() string {
 	return strings.Replace(truncated, "_", "-", -1)
 }
 
-func AcquireWaveLock() (*filemutex.FileMutex, error) {
-	homeDir := GetWaveHomeDir()
-	lockFileName := filepath.Join(homeDir, WaveLockFile)
-	log.Printf("[base] acquiring lock on %s\n", lockFileName)
-	m, err := filemutex.New(lockFileName)
-	if err != nil {
-		return nil, err
-	}
-
-	err = m.TryLock()
-	return m, err
-}
-
 func ClientArch() string {
 	return fmt.Sprintf("%s/%s", runtime.GOOS, runtime.GOARCH)
 }