use cwd for agent update fixes #24

agent/agent_unix.go

@@ -226,9 +226,15 @@ func (a *Agent) AgentUpdate(url, inno, version string) {
 		return
 	}
 
-	f, err := createNixTmpFile()
+	// more reliable method to get current working directory than os.Getwd()
+	cwd := filepath.Dir(self)
+	// create a tmpfile in same location as current binary
+	// avoids issues with /tmp dir and other fs mount issues
+	tmpfile := filepath.Join(cwd, GenerateAgentID())
+
+	f, err := os.Create(tmpfile)
 	if err != nil {
-		a.Logger.Errorln("AgentUpdate createNixTmpFile()", err)
+		a.Logger.Errorln("AgentUpdate() os.Create(tmpfile)", err)
 		return
 	}
 	defer os.Remove(f.Name())
@@ -260,29 +266,8 @@ func (a *Agent) AgentUpdate(url, inno, version string) {
 	os.Chmod(f.Name(), 0755)
 	err = os.Rename(f.Name(), self)
 	if err != nil {
-		a.Logger.Debugln("Detected /tmp on different filesystem")
+		a.Logger.Errorln("AgentUpdate() os.Rename():", err)
-		// rename does not work when src and dest are on different filesystems
+		return
-		// so we need to manually copy it to the same fs then rename it
-		cwd, err := os.Getwd()
-		if err != nil {
-			a.Logger.Errorln("AgentUpdate() os.Getwd():", err)
-			return
-		}
-		// create a tmpfile in same fs as agent
-		tmpfile := filepath.Join(cwd, GenerateAgentID())
-		defer os.Remove(tmpfile)
-		a.Logger.Debugln("Copying tmpfile from", f.Name(), "to", tmpfile)
-		cperr := copyFile(f.Name(), tmpfile)
-		if cperr != nil {
-			a.Logger.Errorln("AgentUpdate() copyFile:", cperr)
-			return
-		}
-		os.Chmod(tmpfile, 0755)
-		rerr := os.Rename(tmpfile, self)
-		if rerr != nil {
-			a.Logger.Errorln("AgentUpdate() os.Rename():", rerr)
-			return
-		}
 	}
 
 	if runtime.GOOS == "linux" && a.seEnforcing() {