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doctor, ipnlocal: add scutil check and tweak logging 

This prints the slightly-parsed output of "scutil --dns" on macOS when
running a bugreport with the diagnose flag. Additionally, this reworks
how the doctor package prints logs to ensure that we don't interleave
log output between checks while still allowing checks to execute
concurrently.

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: If3049f8c4e1b2cf624ed8670883ad6166b15bf7f
andrew/doctor-scutil
Andrew Dunham 2023-02-10 16:05:03 -05:00
parent 78980a4ccf
commit 9bc7a1bf08
8 changed files with 347 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
cmd/tailscaled/depaware.txt
View File

@ -201,6 +201,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
tailscale.com/disco from tailscale.com/derp+
tailscale.com/doctor from tailscale.com/ipn/ipnlocal
tailscale.com/doctor/routetable from tailscale.com/ipn/ipnlocal
tailscale.com/doctor/scutil from tailscale.com/ipn/ipnlocal
tailscale.com/envknob from tailscale.com/control/controlclient+
tailscale.com/health from tailscale.com/control/controlclient+
tailscale.com/health/healthmsg from tailscale.com/ipn/ipnlocal

53
doctor/doctor.go
View File

@ -28,41 +28,54 @@ type Check interface {
// RunChecks runs a list of checks in parallel, and logs any returned errors
// after all checks have returned.
func RunChecks(ctx context.Context, log logger.Logf, checks ...Check) {
func RunChecks(ctx context.Context, logf logger.Logf, checks ...Check) {
if len(checks) == 0 {
return
}
type namedErr struct {
name string
err error
type logRecord struct {
format string
args []any
}
errs := make(chan namedErr, len(checks))
var wg sync.WaitGroup
var (
wg sync.WaitGroup
outputMu sync.Mutex // protecting logf
)
wg.Add(len(checks))
for _, check := range checks {
go func(c Check) {
defer wg.Done()
plog := logger.WithPrefix(log, c.Name()+": ")
errs <- namedErr{
name: c.Name(),
err: c.Run(ctx, plog),
// Log everything in a batch at the end of the function
// so that we don't interleave messages.
var (
logMu sync.Mutex // protects logs; acquire before outputMu
logs []logRecord
)
checkLogf := func(format string, args ...any) {
logMu.Lock()
defer logMu.Unlock()
logs = append(logs, logRecord{format, args})
}
defer func() {
logMu.Lock()
defer logMu.Unlock()
outputMu.Lock()
defer outputMu.Unlock()
name := c.Name()
for _, log := range logs {
logf(name+": "+log.format, log.args...)
}
}()
if err := c.Run(ctx, checkLogf); err != nil {
checkLogf("error: %v", err)
}
}(check)
}
wg.Wait()
close(errs)
for n := range errs {
if n.err == nil {
continue
}
log("check %s: %v", n.name, n.err)
}
}
// CheckFunc creates a Check from a name and a function.

13
doctor/scutil/scutil.go 100644
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@ -0,0 +1,13 @@
// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package scutil provides a doctor.Check that runs scutil to print debug
// information about the system on macOS.
package scutil
// Check implements the doctor.Check interface.
type Check struct{}
func (Check) Name() string {
return "scutil"
}

156
doctor/scutil/scutil_darwin.go 100644
View File

@ -0,0 +1,156 @@
// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package scutil
import (
"context"
"os/exec"
"regexp"
"strconv"
"strings"
"tailscale.com/types/logger"
)
func (Check) Run(ctx context.Context, logf logger.Logf) error {
cmd := exec.CommandContext(ctx, "scutil", "--dns")
out, err := cmd.CombinedOutput()
if err != nil {
logf("error running scutil --dns: %v", err)
return nil
}
parsed, err := parseScutilDNS(logf, string(out))
if err != nil {
logf("error parsing scutil --dns output: %v", err)
return nil
}
for _, section := range parsed.Sections {
logf("section: %s", section.Name)
for _, entry := range section.Entries {
logf(" entry: %s", entry.Name)
for key, val := range entry.Config {
logf(" %s=%q", key, val)
}
for key, list := range entry.ListConfig {
for i, val := range list {
logf(" %s[%d]=%q", key, i, val)
}
}
}
}
return nil
}
type dnsInfo struct {
Sections []*dnsSection
}
type dnsSection struct {
Name string
Entries []*dnsEntry
}
type dnsEntry struct {
Name string
Config map[string]string
ListConfig map[string][]string
}
var (
reSpacePrefix = regexp.MustCompile(`\A\s+[^\s]`)
reNumSuffix = regexp.MustCompile(`\A(.+)\[(\d+)\]\z`)
)
func parseScutilDNS(logf logger.Logf, data string) (*dnsInfo, error) {
lines := strings.Split(strings.TrimSpace(data), "\n")
ret := &dnsInfo{}
const (
stateEntry = iota
stateEntryData
)
var (
currState int = stateEntry
currSection *dnsSection
currEntry *dnsEntry
)
for _, ll := range lines {
switch currState {
case stateEntry:
// We're looking for a new 'resolver' section; if the
// current line has the 'resolver ' prefix, then we've
// found one.
if strings.HasPrefix(ll, "resolver ") {
currEntry = &dnsEntry{
Name: ll,
Config: make(map[string]string),
ListConfig: make(map[string][]string),
}
currSection.Entries = append(currSection.Entries, currEntry)
currState = stateEntryData
continue
}
// Otherwise, if we have a non-blank line treat it as a
// new section.
llTrim := strings.TrimSpace(ll)
if llTrim != "" {
currSection = &dnsSection{
Name: llTrim,
}
ret.Sections = append(ret.Sections, currSection)
// Still looking for a new resolver; no state change.
}
case stateEntryData:
// We're inside a 'resolver' section; if the current
// line doesn't have a prefix of 1 or more spaces, then
// we're done the current section.
if !reSpacePrefix.MatchString(ll) {
// Looking for a new 'resolver' entry.
currState = stateEntry
continue
}
key, val, ok := strings.Cut(ll, ":")
if !ok {
logf("unexpected: did not find ':' in: %q", ll)
continue
}
key = strings.TrimSpace(key)
val = strings.TrimSpace(val)
// If there's a '[##]' suffix of key, then we treat
// this as a list of items.
if sm := reNumSuffix.FindStringSubmatch(key); sm != nil {
index, err := strconv.Atoi(sm[2])
if err != nil {
logf("unexpected: bad index: %q", sm[2])
continue
}
key = sm[1]
sl := currEntry.ListConfig[key]
if index == len(sl) {
sl = append(sl, val)
} else {
logf("unexpected: out-of-order index: %d (existing len=%d)", index, len(sl))
continue
}
currEntry.ListConfig[key] = sl
} else {
if _, ok := currEntry.Config[key]; ok {
logf("unexpected: duplicate key %q", key)
continue
}
currEntry.Config[key] = val
}
}
}
return ret, nil
}

124
doctor/scutil/scutil_darwin_test.go 100644
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@ -0,0 +1,124 @@
// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package scutil
import (
"reflect"
"testing"
"github.com/davecgh/go-spew/spew"
)
// Example output from a 2022 MacBook Pro with Tailscale installed, slightly
// redacted for length/clarity.
const scutilDnsOutput = `DNS configuration
resolver #1
search domain[0] : example.ts.net
search domain[1] : tailscale.com.beta.tailscale.net
search domain[2] : ts-dns.test
nameserver[0] : 100.100.100.100
if_index : 30 (utun3)
flags : Supplemental, Request A records, Request AAAA records
reach : 0x00000003 (Reachable,Transient Connection)
order : 100200
resolver #2
nameserver[0] : 8.8.8.8
nameserver[1] : 8.8.4.4
flags : Request A records, Request AAAA records
reach : 0x00000002 (Reachable)
order : 200000
DNS configuration (for scoped queries)
resolver #1
nameserver[0] : 8.8.8.8
nameserver[1] : 8.8.4.4
if_index : 15 (en0)
flags : Scoped, Request A records, Request AAAA records
reach : 0x00000002 (Reachable)
resolver #2
search domain[0] : example.ts.net
search domain[1] : tailscale.com.beta.tailscale.net
search domain[2] : ts-dns.test
nameserver[0] : 100.100.100.100
if_index : 30 (utun3)
flags : Scoped, Request A records, Request AAAA records
reach : 0x00000003 (Reachable,Transient Connection)
`
func TestParseScutilDNS(t *testing.T) {
info, err := parseScutilDNS(t.Logf, scutilDnsOutput)
if err != nil {
t.Fatal(err)
}
expected := &dnsInfo{Sections: []*dnsSection{
{
Name: "DNS configuration",
Entries: []*dnsEntry{
{
Name: "resolver #1",
Config: map[string]string{
"if_index": "30 (utun3)",
"flags": "Supplemental, Request A records, Request AAAA records",
"reach": "0x00000003 (Reachable,Transient Connection)",
"order": "100200",
},
ListConfig: map[string][]string{
"search domain": []string{"example.ts.net", "tailscale.com.beta.tailscale.net", "ts-dns.test"},
"nameserver": []string{"100.100.100.100"},
},
},
{
Name: "resolver #2",
Config: map[string]string{
"flags": "Request A records, Request AAAA records",
"reach": "0x00000002 (Reachable)",
"order": "200000",
},
ListConfig: map[string][]string{
"nameserver": []string{"8.8.8.8", "8.8.4.4"},
},
},
},
},
{
Name: "DNS configuration (for scoped queries)",
Entries: []*dnsEntry{
{
Name: "resolver #1",
Config: map[string]string{
"if_index": "15 (en0)",
"flags": "Scoped, Request A records, Request AAAA records",
"reach": "0x00000002 (Reachable)",
},
ListConfig: map[string][]string{
"nameserver": []string{"8.8.8.8", "8.8.4.4"},
},
},
{
Name: "resolver #2",
Config: map[string]string{
"if_index": "30 (utun3)",
"flags": "Scoped, Request A records, Request AAAA records",
"reach": "0x00000003 (Reachable,Transient Connection)",
},
ListConfig: map[string][]string{
"search domain": []string{"example.ts.net", "tailscale.com.beta.tailscale.net", "ts-dns.test"},
"nameserver": []string{"100.100.100.100"},
},
},
},
},
}}
if !reflect.DeepEqual(info, expected) {
t.Errorf("parse mismatch:\ngot: %s\nwant: %s",
spew.Sdump(info),
spew.Sdump(expected),
)
}
}

17
doctor/scutil/scutil_notdarwin.go 100644
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@ -0,0 +1,17 @@
// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
//go:build !darwin
package scutil
import (
"context"
"tailscale.com/types/logger"
)
func (Check) Run(ctx context.Context, logf logger.Logf) error {
// unimplemented
return nil
}

2
go.mod
View File

@ -18,6 +18,7 @@ require (
github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
github.com/creack/pty v1.1.17
github.com/dave/jennifer v1.4.1
github.com/davecgh/go-spew v1.1.1
github.com/dblohm7/wingoes v0.0.0-20221124203957-6ac47ab19aa5
github.com/dsnet/try v0.0.3
github.com/evanw/esbuild v0.14.53
@ -139,7 +140,6 @@ require (
github.com/cloudflare/circl v1.1.0 // indirect
github.com/containerd/stargz-snapshotter/estargz v0.11.4 // indirect
github.com/daixiang0/gci v0.2.9 // indirect
github.com/davecgh/go-spew v1.1.1 // indirect
github.com/denis-tingajkin/go-header v0.4.2 // indirect
github.com/docker/cli v20.10.16+incompatible // indirect
github.com/docker/distribution v2.8.1+incompatible // indirect

2
ipn/ipnlocal/local.go
View File

@ -35,6 +35,7 @@ import (
"tailscale.com/control/controlclient"
"tailscale.com/doctor"
"tailscale.com/doctor/routetable"
"tailscale.com/doctor/scutil"
"tailscale.com/envknob"
"tailscale.com/health"
"tailscale.com/health/healthmsg"
@ -4628,6 +4629,7 @@ func (b *LocalBackend) Doctor(ctx context.Context, logf logger.Logf) {
var checks []doctor.Check
checks = append(checks, routetable.Check{})
checks = append(checks, scutil.Check{})
// Print a log message if any of the global DNS resolvers are Tailscale
// IPs; this can interfere with our ability to connect to the Tailscale