Add root check and prettier tables

main.go

@@ -54,6 +54,13 @@ var osImages = map[string]OSImage{
         },
 }
 
+func requireRoot() {
+        if os.Geteuid() != 0 {
+                fmt.Fprintln(os.Stderr, "mnmivm must be run as root. Try: `sudo mnmivm` or login as the root user")
+                os.Exit(1)
+        }
+}
+
 func ensureDirs() {
         for _, d := range []string{imageDir, vmDirBase} {
                 if err := os.MkdirAll(d, 0755); err != nil {
@@ -176,6 +183,64 @@ disable_root: true
         }
 }
 
+func renderBoxTable(headers []string, rows [][]string) {
+        colWidths := make([]int, len(headers))
+
+        // compute column widths
+        for i, h := range headers {
+                colWidths[i] = len(h)
+        }
+        for _, row := range rows {
+                for i, cell := range row {
+                        if len(cell) > colWidths[i] {
+                                colWidths[i] = len(cell)
+                        }
+                }
+        }
+
+        // helpers
+        repeat := func(s string, n int) string {
+                return strings.Repeat(s, n)
+        }
+
+        drawRow := func(left, mid, right string) {
+                fmt.Print(left)
+                for i, w := range colWidths {
+                        fmt.Print(repeat("─", w+2))
+                        if i < len(colWidths)-1 {
+                                fmt.Print(mid)
+                        }
+                }
+                fmt.Println(right)
+        }
+
+        // top border
+        drawRow("┌", "┬", "┐")
+
+        // header row
+        fmt.Print("│")
+        for i, h := range headers {
+                fmt.Printf(" %-*s │", colWidths[i], h)
+        }
+        fmt.Println()
+
+        // header separator
+        drawRow("├", "┼", "┤")
+
+        // data rows
+        for _, row := range rows {
+                fmt.Print("│")
+                for i, cell := range row {
+                        fmt.Printf(" %-*s │", colWidths[i], cell)
+                }
+                fmt.Println()
+        }
+
+        // bottom border
+        drawRow("└", "┴", "┘")
+}
+
+
 func createVM(name, osName, pubKeyPath string) {
         if _, ok := osImages[osName]; !ok {
                 panic("unsupported OS: " + osName)
@@ -298,9 +363,16 @@ func vmRunning(name string) bool {
 func listVMs() {
         entries, _ := os.ReadDir(vmDirBase)
 
-        fmt.Printf("%-12s %-8s %-8s %-16s %-16s %s\n",
-                "NAME", "STATE", "OS", "SSH", "VNC", "PUBKEY")
-        fmt.Println(strings.Repeat("-", 90))
+        headers := []string{
+                "NAME",
+                "STATE",
+                "OS",
+                "SSH",
+                "VNC",
+                "PUBKEY",
+        }
+
+        rows := [][]string{}
 
         for _, e := range entries {
                 name := e.Name()
@@ -312,6 +384,7 @@ func listVMs() {
                 }
 
                 osName := readFileTrim(filepath.Join(dir, "os.name"))
+
                 sshPort := readFileTrim(filepath.Join(dir, "ssh.port"))
                 vncPort := readFileTrim(filepath.Join(dir, "vnc.port"))
 
@@ -325,12 +398,27 @@ func listVMs() {
                         vnc = "0.0.0.0:" + vncPort
                 }
 
-                fmt.Printf("%-12s %-8s %-8s %-16s %-16s %s\n",
-                        name, state, osName, ssh, vnc, vmPubKeyPath(name))
-        }
+                rows = append(rows, []string{
+                        name,
+                        state,
+                        osName,
+                        ssh,
+                        vnc,
+                        vmPubKeyPath(name),
+                })
         }
 
+        if len(rows) == 0 {
+                fmt.Println("No VMs found.")
+                return
+        }
+
+        renderBoxTable(headers, rows)
+}
+
+
 func main() {
+	requireRoot()
         if len(os.Args) < 2 {
                 usage()
         }