mirror of
https://github.com/tailscale/tailscale.git
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46ce80758d
In prep for reducing garbage, being able to reuse memory. So far this
doesn't actually reuse much. This is just changing signatures around.
But some improvement in any case:
bradfitz@tsdev:~/src/tailscale.com$ ~/go/bin/benchstat before after
name old time/op new time/op delta
GetList-8 11.8ms ± 9% 9.9ms ± 3% -15.98% (p=0.000 n=10+10)
name old alloc/op new alloc/op delta
GetList-8 99.5kB ± 2% 91.9kB ± 0% -7.62% (p=0.000 n=9+9)
name old allocs/op new allocs/op delta
GetList-8 3.05k ± 1% 2.93k ± 0% -3.83% (p=0.000 n=8+9)
More later, once parsers can reuse strings from previous parses.
Updates #5958
Change-Id: I76cd5048246dd24d11c4e263d8bb8041747fb2b0
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
110 lines
2.6 KiB
Go
110 lines
2.6 KiB
Go
// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build darwin && !ios
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// +build darwin,!ios
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package portlist
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import (
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"bufio"
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"bytes"
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"fmt"
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"log"
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"os/exec"
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"strings"
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"sync/atomic"
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"time"
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)
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// We have to run netstat, which is a bit expensive, so don't do it too often.
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const pollInterval = 5 * time.Second
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func appendListeningPorts(base []Port) ([]Port, error) {
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return appendListeningPortsNetstat(base, "-na")
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}
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var lsofFailed int64 // atomic bool
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// In theory, lsof could replace the function of both listPorts() and
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// addProcesses(), since it provides a superset of the netstat output.
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// However, "netstat -na" runs ~100x faster than lsof on my machine, so
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// we should do it only if the list of open ports has actually changed.
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//
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// This fails in a macOS sandbox (i.e. in the Mac App Store or System
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// Extension GUI build), but does at least work in the
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// tailscaled-on-macos mode.
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func addProcesses(pl []Port) ([]Port, error) {
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if atomic.LoadInt64(&lsofFailed) != 0 {
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// This previously failed in the macOS sandbox, so don't try again.
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return pl, nil
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}
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exe, err := exec.LookPath("lsof")
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if err != nil {
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return nil, fmt.Errorf("lsof: lookup: %v", err)
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}
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output, err := exec.Command(exe, "-F", "-n", "-P", "-O", "-S2", "-T", "-i4", "-i6").Output()
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if err != nil {
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var stderr []byte
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if xe, ok := err.(*exec.ExitError); ok {
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stderr = xe.Stderr
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}
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// fails when run in a macOS sandbox, so make this non-fatal.
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if atomic.CompareAndSwapInt64(&lsofFailed, 0, 1) {
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log.Printf("portlist: can't run lsof in Mac sandbox; omitting process names from service list. Error details: %v, %s", err, bytes.TrimSpace(stderr))
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}
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return pl, nil
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}
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type ProtoPort struct {
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proto string
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port uint16
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}
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m := map[ProtoPort]*Port{}
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for i := range pl {
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pp := ProtoPort{pl[i].Proto, pl[i].Port}
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m[pp] = &pl[i]
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}
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r := bytes.NewReader(output)
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scanner := bufio.NewScanner(r)
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var cmd, proto string
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for scanner.Scan() {
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line := scanner.Text()
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if line == "" {
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continue
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}
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field, val := line[0], line[1:]
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switch field {
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case 'p':
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// starting a new process
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cmd = ""
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proto = ""
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case 'c':
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cmd = val
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case 'P':
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proto = strings.ToLower(val)
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case 'n':
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if strings.Contains(val, "->") {
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continue
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}
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// a listening port
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port := parsePort(val)
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if port > 0 {
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pp := ProtoPort{proto, uint16(port)}
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p := m[pp]
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switch {
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case p != nil:
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p.Process = cmd
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default:
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// ignore: processes and ports come and go
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}
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}
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}
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}
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return pl, nil
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}
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