tailscale/portlist/portlist_darwin.go

100 lines
2.3 KiB
Go

// 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.
// +build !linux,!windows
package portlist
import (
"bufio"
"bytes"
"fmt"
"log"
"os"
"strings"
exec "tailscale.com/tempfork/osexec"
)
// We have to run netstat, which is a bit expensive, so don't do it too often.
const POLL_SECONDS = 5
func listPorts() (List, error) {
return listPortsNetstat("-na")
}
// In theory, lsof could replace the function of both listPorts() and
// addProcesses(), since it provides a superset of the netstat output.
// However, "netstat -na" runs ~100x faster than lsof on my machine, so
// we should do it only if the list of open ports has actually changed.
//
// TODO(apenwarr): this fails in a macOS sandbox (ie. our usual case).
// We might as well just delete this code if we can't find a solution.
func addProcesses(pl []Port) ([]Port, error) {
exe, err := exec.LookPath("lsof")
if err != nil {
return nil, fmt.Errorf("lsof: lookup: %v", err)
}
c := exec.Cmd{
Path: exe,
Args: []string{exe, "-F", "-n", "-P", "-O", "-S2", "-T", "-i4", "-i6"},
}
output, err := c.Output()
if err != nil {
xe, ok := err.(*exec.ExitError)
stderr := ""
if ok {
stderr = strings.TrimSpace(string(xe.Stderr))
}
// fails when run in a macOS sandbox, so make this non-fatal.
log.Printf("portlist: lsof: %v (%q)\n", err, stderr)
return pl, nil
}
type ProtoPort struct {
proto string
port uint16
}
m := map[ProtoPort]*Port{}
for i := range pl {
pp := ProtoPort{pl[i].Proto, pl[i].Port}
m[pp] = &pl[i]
}
r := bytes.NewReader(output)
scanner := bufio.NewScanner(r)
var cmd, proto string
for scanner.Scan() {
line := scanner.Text()
if line[0] == 'p' {
// starting a new process
cmd = ""
proto = ""
} else if line[0] == 'c' {
cmd = line[1:len(line)]
} else if line[0] == 'P' {
proto = strings.ToLower(line[1:len(line)])
} else if line[0] == 'n' {
rest := line[1:len(line)]
i := strings.Index(rest, "->")
if i < 0 {
// a listening port
port := parsePort(rest)
if port > 0 {
pp := ProtoPort{proto, uint16(port)}
p := m[pp]
if p != nil {
p.Process = cmd
} else {
fmt.Fprintf(os.Stderr, "weird: missing %v\n", pp)
}
}
}
}
}
return pl, nil
}