init commit

osdetect.go

@@ -0,0 +1,76 @@
+package main
+
+import (
+	"bufio"
+	"os"
+	"strings"
+)
+
+// OSInfo holds the detected distribution identity and init system.
+type OSInfo struct {
+	ID      string
+	Version string
+	Init    string // "systemd" or "openrc"
+}
+
+// detectOS parses /etc/os-release and maps the distro to its init system.
+func detectOS() *OSInfo {
+	f, err := os.Open("/etc/os-release")
+	if err != nil {
+		die("Cannot detect OS: /etc/os-release not found")
+	}
+	defer f.Close()
+
+	vals := map[string]string{}
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		if i := strings.Index(line, "="); i >= 0 {
+			key := strings.TrimSpace(line[:i])
+			vals[key] = unquoteShell(line[i+1:])
+		}
+	}
+
+	osInfo := &OSInfo{
+		ID:      valueOr(vals["ID"], "unknown"),
+		Version: valueOr(vals["VERSION_ID"], "unknown"),
+	}
+
+	switch osInfo.ID {
+	case "ubuntu", "debian", "linuxmint":
+		osInfo.Init = "systemd"
+	case "alpine":
+		osInfo.Init = "openrc"
+	default:
+		die("Unsupported OS: %s (supported: ubuntu, debian, linuxmint, alpine)", osInfo.ID)
+	}
+
+	// A systemd-based distro may still be running here without systemd as
+	// PID 1 — the container case (e.g. the Linux Mint image used for the
+	// alternative container build). systemd creates /run/systemd/system only
+	// when it is actually active as the init system, so its absence is the
+	// standard way to detect this. Fall back to driving awg-quick directly,
+	// same as the Alpine/OpenRC path.
+	if osInfo.Init == "systemd" && !systemdRunning() {
+		osInfo.Init = "openrc"
+	}
+
+	info("Detected OS: %s %s (init: %s)", osInfo.ID, osInfo.Version, osInfo.Init)
+	return osInfo
+}
+
+// systemdRunning reports whether systemd is active as PID 1.
+func systemdRunning() bool {
+	_, err := os.Stat("/run/systemd/system")
+	return err == nil
+}
+
+func valueOr(v, def string) string {
+	if v == "" {
+		return def
+	}
+	return v
+}