init

Signed-off-by: Hadi <[email protected]>

internal/network/nmcli.go

@@ -0,0 +1,120 @@
+// Package network wraps nmcli to read and control network state
+// (Wi-Fi, Ethernet, VPN). Every exported function shells out to nmcli;
+// there is no direct D-Bus/NetworkManager integration.
+package network
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"os/exec"
+	"strings"
+	"time"
+)
+
+var (
+	ErrNotFound   = errors.New("nmcli not found in PATH")
+	ErrNotRunning = errors.New("NetworkManager is not running")
+)
+
+const defaultTimeout = 15 * time.Second
+
+// CheckAvailable reports whether nmcli is installed and NetworkManager is
+// reachable. Call it before using the rest of the package.
+func CheckAvailable() error {
+	if _, err := exec.LookPath("nmcli"); err != nil {
+		return ErrNotFound
+	}
+	out, err := run("-t", "-f", "RUNNING", "general")
+	if err != nil {
+		return fmt.Errorf("%w: %v", ErrNotRunning, err)
+	}
+	if strings.TrimSpace(out) != "running" {
+		return ErrNotRunning
+	}
+	return nil
+}
+
+func run(args ...string) (string, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTimeout)
+	defer cancel()
+
+	cmd := exec.CommandContext(ctx, "nmcli", args...) // #nosec G204 -- args are fixed nmcli subcommands or user-supplied SSID/password, never shell-interpreted
+	var stdout, stderr bytes.Buffer
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+
+	if err := cmd.Run(); err != nil {
+		if errors.Is(err, exec.ErrNotFound) {
+			return "", ErrNotFound
+		}
+		msg := strings.TrimSpace(stderr.String())
+		if msg == "" {
+			msg = err.Error()
+		}
+		return "", fmt.Errorf("nmcli %s: %s", strings.Join(args, " "), msg)
+	}
+	return stdout.String(), nil
+}
+
+// getField runs `nmcli -g <field> ...` and returns the single trimmed value.
+func getField(field string, args ...string) (string, error) {
+	out, err := run(append([]string{"-g", field}, args...)...)
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(out), nil
+}
+
+// runTerse runs nmcli with -t -f <fields> and parses each output line into
+// its colon-separated columns, unescaping nmcli's `\:` and `\\`.
+func runTerse(fields string, args ...string) ([][]string, error) {
+	out, err := run(append([]string{"-t", "-f", fields}, args...)...)
+	if err != nil {
+		return nil, err
+	}
+	out = strings.TrimRight(out, "\n")
+	if out == "" {
+		return nil, nil
+	}
+
+	lines := strings.Split(out, "\n")
+	rows := make([][]string, 0, len(lines))
+	for _, line := range lines {
+		rows = append(rows, parseTerseLine(line))
+	}
+	return rows, nil
+}
+
+func parseTerseLine(line string) []string {
+	var fields []string
+	var cur strings.Builder
+	escaped := false
+	for _, r := range line {
+		if escaped {
+			cur.WriteRune(r)
+			escaped = false
+			continue
+		}
+		switch r {
+		case '\\':
+			escaped = true
+		case ':':
+			fields = append(fields, cur.String())
+			cur.Reset()
+		default:
+			cur.WriteRune(r)
+		}
+	}
+	fields = append(fields, cur.String())
+	return fields
+}
+
+// field is a small helper to safely index a parsed terse row.
+func field(row []string, i int) string {
+	if i < 0 || i >= len(row) {
+		return ""
+	}
+	return row[i]
+}