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1dfdee8521
When using the resolve.conf file for setting DNS, it is possible that some other services will trample the file and overwrite our set DNS server. Experiments has shown this to be a racy error depending on how quickly processes start. Make an attempt to trample back the file a limited number of times if the file is changed. Updates #16635 Signed-off-by: Claus Lensbøl <claus@tailscale.com>
46 lines
1.3 KiB
Go
46 lines
1.3 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package dns
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import (
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"fmt"
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"os"
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"tailscale.com/control/controlknobs"
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"tailscale.com/health"
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"tailscale.com/types/logger"
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"tailscale.com/util/eventbus"
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"tailscale.com/util/syspolicy/policyclient"
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)
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// NewOSConfigurator creates a new OS configurator.
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//
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// The health tracker may be nil; the knobs may be nil and are ignored on this platform.
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func NewOSConfigurator(logf logger.Logf, health *health.Tracker, bus *eventbus.Bus, _ policyclient.Client, _ *controlknobs.Knobs, _ string) (OSConfigurator, error) {
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bs, err := os.ReadFile("/etc/resolv.conf")
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if os.IsNotExist(err) {
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return newDirectManager(logf, health, bus), nil
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}
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if err != nil {
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return nil, fmt.Errorf("reading /etc/resolv.conf: %w", err)
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}
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switch resolvOwner(bs) {
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case "resolvconf":
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switch resolvconfStyle() {
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case "":
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return newDirectManager(logf, health, bus), nil
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case "debian":
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return newDebianResolvconfManager(logf)
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case "openresolv":
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return newOpenresolvManager(logf)
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default:
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logf("[unexpected] got unknown flavor of resolvconf %q, falling back to direct manager", resolvconfStyle())
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return newDirectManager(logf, health, bus), nil
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}
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default:
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return newDirectManager(logf, health, bus), nil
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}
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}
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