tailscale/portlist/netstat_exec.go

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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build (windows || freebsd || openbsd || darwin) && !ios && !js
// +build windows freebsd openbsd darwin
// +build !ios
// +build !js
package portlist
import (
"fmt"
"os/exec"
"strings"
)
var osHideWindow func(*exec.Cmd) // non-nil on Windows; see portlist_windows.go
// hideWindow returns c. On Windows it first sets SysProcAttr.HideWindow.
func hideWindow(c *exec.Cmd) *exec.Cmd {
if osHideWindow != nil {
osHideWindow(c)
}
return c
}
func listPortsNetstat(arg string) (List, error) {
exe, err := exec.LookPath("netstat")
if err != nil {
return nil, fmt.Errorf("netstat: lookup: %v", err)
}
output, err := hideWindow(exec.Command(exe, arg)).Output()
if err != nil {
xe, ok := err.(*exec.ExitError)
stderr := ""
if ok {
stderr = strings.TrimSpace(string(xe.Stderr))
}
return nil, fmt.Errorf("netstat: %v (%q)", err, stderr)
}
return parsePortsNetstat(string(output)), nil
}