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3511d1f8a2
When we're starting child processes on Windows that are CLI programs that don't need to output to a console, we should pass in DETACHED_PROCESS as a CreationFlag on SysProcAttr. This prevents the OS from even creating a console for the child (and paying the associated time/space penalty for new conhost processes). This is more efficient than letting the OS create the console window and then subsequently trying to hide it, which we were doing at a few callsites. Fixes #12270 Signed-off-by: Aaron Klotz <aaron@tailscale.com>
35 lines
788 B
Go
35 lines
788 B
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/exec"
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"syscall"
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"golang.org/x/sys/windows"
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)
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func flushCaches() error {
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cmd := exec.Command("ipconfig", "/flushdns")
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cmd.SysProcAttr = &syscall.SysProcAttr{
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CreationFlags: windows.DETACHED_PROCESS,
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}
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out, err := cmd.CombinedOutput()
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if err != nil {
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return fmt.Errorf("%v (output: %s)", err, out)
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}
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return nil
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}
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// Flush clears the local resolver cache.
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//
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// Only Windows has a public dns.Flush, needed in router_windows.go. Other
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// platforms like Linux need a different flush implementation depending on
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// the DNS manager. There is a FlushCaches method on the manager which
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// can be used on all platforms.
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func Flush() error {
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return flushCaches()
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}
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