tailscale/net/dns/resolvconf.go

31 lines
743 B
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
//go:build linux || freebsd || openbsd
package dns
import (
"bytes"
"os/exec"
)
func resolvconfStyle() string {
if _, err := exec.LookPath("resolvconf"); err != nil {
return ""
}
output, err := exec.Command("resolvconf", "--version").CombinedOutput()
if err != nil {
// Debian resolvconf doesn't understand --version, and
// exits with a specific error code.
if exitErr, ok := err.(*exec.ExitError); ok && exitErr.ExitCode() == 99 {
return "debian"
}
}
if bytes.HasPrefix(output, []byte("Debian resolvconf")) {
return "debian"
}
// Treat everything else as openresolv, by far the more popular implementation.
return "openresolv"
}