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5d07c17b93
During resolv.conf update, old 'search' lines are cleared but '\n' is not deleted, leaving behind a new blank line on every update. This adds 's' flag to regexp, so '\n' is included in the match and deleted when old lines are cleared. Also, insert missing `\n` when updated 'search' line is appended to resolv.conf. Signed-off-by: Renato Aguiar <renato@renatoaguiar.net>
130 lines
2.6 KiB
Go
130 lines
2.6 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build openbsd
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package dns
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import (
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"bytes"
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"os"
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"os/exec"
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"regexp"
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"strings"
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"tailscale.com/net/dns/resolvconffile"
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"tailscale.com/types/logger"
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)
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func newResolvdManager(logf logger.Logf, interfaceName string) (*resolvdManager, error) {
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return &resolvdManager{
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logf: logf,
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ifName: interfaceName,
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fs: directFS{},
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}, nil
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}
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// resolvdManager is an OSConfigurator which uses route(1) to teach OpenBSD's
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// resolvd(8) about DNS servers.
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type resolvdManager struct {
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logf logger.Logf
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ifName string
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fs directFS
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}
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func (m *resolvdManager) SetDNS(config OSConfig) error {
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args := []string{
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"nameserver",
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m.ifName,
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}
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origResolv, err := m.readAndCopy(resolvConf, backupConf, 0644)
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if err != nil {
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return err
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}
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newResolvConf := removeSearchLines(origResolv)
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for _, ns := range config.Nameservers {
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args = append(args, ns.String())
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}
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var newSearch = []string{
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"search",
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}
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for _, s := range config.SearchDomains {
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newSearch = append(newSearch, s.WithoutTrailingDot())
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}
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if len(newSearch) > 1 {
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newResolvConf = append(newResolvConf, []byte(strings.Join(newSearch, " "))...)
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newResolvConf = append(newResolvConf, '\n')
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}
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err = m.fs.WriteFile(resolvConf, newResolvConf, 0644)
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if err != nil {
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return err
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}
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cmd := exec.Command("/sbin/route", args...)
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return cmd.Run()
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}
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func (m *resolvdManager) SupportsSplitDNS() bool {
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return false
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}
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func (m *resolvdManager) GetBaseConfig() (OSConfig, error) {
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cfg, err := m.readResolvConf()
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if err != nil {
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return OSConfig{}, err
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}
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return cfg, nil
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}
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func (m *resolvdManager) Close() error {
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// resolvd handles teardown of nameservers so we only need to write back the original
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// config and be done.
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_, err := m.readAndCopy(backupConf, resolvConf, 0644)
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if err != nil {
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return err
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}
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return m.fs.Remove(backupConf)
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}
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func (m *resolvdManager) readAndCopy(a, b string, mode os.FileMode) ([]byte, error) {
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orig, err := m.fs.ReadFile(a)
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if err != nil {
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return nil, err
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}
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err = m.fs.WriteFile(b, orig, mode)
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if err != nil {
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return nil, err
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}
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return orig, nil
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}
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func (m resolvdManager) readResolvConf() (config OSConfig, err error) {
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b, err := m.fs.ReadFile(resolvConf)
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if err != nil {
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return OSConfig{}, err
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}
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rconf, err := resolvconffile.Parse(bytes.NewReader(b))
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if err != nil {
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return config, err
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}
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return OSConfig{
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Nameservers: rconf.Nameservers,
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SearchDomains: rconf.SearchDomains,
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}, nil
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}
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func removeSearchLines(orig []byte) []byte {
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re := regexp.MustCompile(`(?ms)^search\s+.+$`)
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return re.ReplaceAll(orig, []byte(""))
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}
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