From 2244c21b765e089e49fede0cc27af7f9f76bae4d Mon Sep 17 00:00:00 2001
From: Eugene Bujak <hmage@hmage.net>
Date: Sun, 7 Oct 2018 00:58:59 +0300
Subject: [PATCH] Fix race conditions found by go's race detector
---
config.go | 2 +-
control.go | 7 +++++--
coredns_plugin/coredns_plugin.go | 21 ++++++++++++++++++---
coredns_plugin/querylog.go | 6 ++++++
stats.go | 10 ++++++++++
5 files changed, 40 insertions(+), 6 deletions(-)
diff --git a/config.go b/config.go
index 8a753a49..ec0843b2 100644
--- a/config.go
+++ b/config.go
@@ -27,7 +27,7 @@ type configuration struct {
Filters []filter `yaml:"filters"`
UserRules []string `yaml:"user_rules"`
- sync.Mutex `yaml:"-"`
+ sync.RWMutex `yaml:"-"`
}
type coreDNSConfig struct {
diff --git a/control.go b/control.go
index d60c6509..cc902f3a 100644
--- a/control.go
+++ b/control.go
@@ -789,10 +789,11 @@ func handleFilteringStatus(w http.ResponseWriter, r *http.Request) {
"enabled": config.CoreDNS.FilteringEnabled,
}
+ config.RLock()
data["filters"] = config.Filters
data["user_rules"] = config.UserRules
-
json, err := json.Marshal(data)
+ config.RUnlock()
if err != nil {
errortext := fmt.Sprintf("Unable to marshal status json: %s", err)
@@ -1122,7 +1123,6 @@ func runFilterRefreshers() {
func refreshFiltersIfNeccessary() int {
now := time.Now()
config.Lock()
- defer config.Unlock()
// deduplicate
// TODO: move it somewhere else
@@ -1154,6 +1154,7 @@ func refreshFiltersIfNeccessary() int {
updateCount++
}
}
+ config.Unlock()
if updateCount > 0 {
err := writeFilterFile()
@@ -1237,6 +1238,7 @@ func writeFilterFile() error {
log.Printf("Writing filter file: %s", filterpath)
// TODO: check if file contents have modified
data := []byte{}
+ config.RLock()
filters := config.Filters
for _, filter := range filters {
if !filter.Enabled {
@@ -1249,6 +1251,7 @@ func writeFilterFile() error {
data = append(data, []byte(rule)...)
data = append(data, '\n')
}
+ config.RUnlock()
err := ioutil.WriteFile(filterpath+".tmp", data, 0644)
if err != nil {
log.Printf("Couldn't write filter file: %s", err)
diff --git a/coredns_plugin/coredns_plugin.go b/coredns_plugin/coredns_plugin.go
index 530e2c2b..dcdb50c8 100644
--- a/coredns_plugin/coredns_plugin.go
+++ b/coredns_plugin/coredns_plugin.go
@@ -55,6 +55,8 @@ type plug struct {
ParentalBlockHost string
QueryLogEnabled bool
BlockedTTL uint32 // in seconds, default 3600
+
+ sync.RWMutex
}
var defaultPlugin = plug{
@@ -246,17 +248,21 @@ func (p *plug) parseEtcHosts(text string) bool {
}
func (p *plug) onShutdown() error {
+ p.Lock()
p.d.Destroy()
p.d = nil
+ p.Unlock()
return nil
}
func (p *plug) onFinalShutdown() error {
+ logBufferLock.Lock()
err := flushToFile(logBuffer)
if err != nil {
log.Printf("failed to flush to file: %s", err)
return err
}
+ logBufferLock.Unlock()
return nil
}
@@ -293,9 +299,11 @@ func doStatsLookup(ch interface{}, doFunc statsFunc, name string, lookupstats *d
}
func (p *plug) doStats(ch interface{}, doFunc statsFunc) {
+ p.RLock()
stats := p.d.GetStats()
doStatsLookup(ch, doFunc, "safebrowsing", &stats.Safebrowsing)
doStatsLookup(ch, doFunc, "parental", &stats.Parental)
+ p.RUnlock()
}
// Describe is called by prometheus handler to know stat types
@@ -365,12 +373,12 @@ func (p *plug) genSOA(r *dns.Msg) []dns.RR {
}
Ns := "fake-for-negative-caching.adguard.com."
- soa := defaultSOA
+ soa := *defaultSOA
soa.Hdr = header
soa.Mbox = Mbox
soa.Ns = Ns
- soa.Serial = uint32(time.Now().Unix())
- return []dns.RR{soa}
+ soa.Serial = 100500 // faster than uint32(time.Now().Unix())
+ return []dns.RR{&soa}
}
func (p *plug) writeNXdomain(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
@@ -397,13 +405,17 @@ func (p *plug) serveDNSInternal(ctx context.Context, w dns.ResponseWriter, r *dn
for _, question := range r.Question {
host := strings.ToLower(strings.TrimSuffix(question.Name, "."))
// is it a safesearch domain?
+ p.RLock()
if val, ok := p.d.SafeSearchDomain(host); ok {
rcode, err := p.replaceHostWithValAndReply(ctx, w, r, host, val, question)
if err != nil {
+ p.RUnlock()
return rcode, dnsfilter.Result{}, err
}
+ p.RUnlock()
return rcode, dnsfilter.Result{Reason: dnsfilter.FilteredSafeSearch}, err
}
+ p.RUnlock()
// is it in hosts?
if val, ok := p.hosts[host]; ok {
@@ -425,11 +437,14 @@ func (p *plug) serveDNSInternal(ctx context.Context, w dns.ResponseWriter, r *dn
}
// needs to be filtered instead
+ p.RLock()
result, err := p.d.CheckHost(host)
if err != nil {
log.Printf("plugin/dnsfilter: %s\n", err)
+ p.RUnlock()
return dns.RcodeServerFailure, dnsfilter.Result{}, fmt.Errorf("plugin/dnsfilter: %s", err)
}
+ p.RUnlock()
if result.IsFiltered {
switch result.Reason {
diff --git a/coredns_plugin/querylog.go b/coredns_plugin/querylog.go
index 808450db..eb848fb8 100644
--- a/coredns_plugin/querylog.go
+++ b/coredns_plugin/querylog.go
@@ -10,6 +10,7 @@ import (
"runtime"
"strconv"
"strings"
+ "sync"
"time"
"github.com/AdguardTeam/AdguardDNS/dnsfilter"
@@ -23,6 +24,7 @@ const (
)
var (
+ logBufferLock sync.RWMutex
logBuffer []logEntry
)
@@ -65,11 +67,13 @@ func logRequest(question *dns.Msg, answer *dns.Msg, result dnsfilter.Result, ela
}
var flushBuffer []logEntry
+ logBufferLock.Lock()
logBuffer = append(logBuffer, entry)
if len(logBuffer) >= logBufferCap {
flushBuffer = logBuffer
logBuffer = nil
}
+ logBufferLock.Unlock()
if len(flushBuffer) > 0 {
// write to file
// do it in separate goroutine -- we are stalling DNS response this whole time
@@ -81,7 +85,9 @@ func logRequest(question *dns.Msg, answer *dns.Msg, result dnsfilter.Result, ela
func handleQueryLog(w http.ResponseWriter, r *http.Request) {
// TODO: fetch values from disk if len(logBuffer) < queryLogSize
// TODO: cache output
+ logBufferLock.RLock()
values := logBuffer
+ logBufferLock.RUnlock()
var data = []map[string]interface{}{}
for _, entry := range values {
var q *dns.Msg
diff --git a/stats.go b/stats.go
index 29f36fbf..a3231faf 100644
--- a/stats.go
+++ b/stats.go
@@ -12,6 +12,7 @@ import (
"path/filepath"
"strconv"
"strings"
+ "sync"
"syscall"
"time"
)
@@ -57,6 +58,7 @@ type stats struct {
PerDay periodicStats
LastSeen statsEntry
+ sync.RWMutex
}
var statistics stats
@@ -71,10 +73,12 @@ func init() {
}
func purgeStats() {
+ statistics.Lock()
initPeriodicStats(&statistics.PerSecond)
initPeriodicStats(&statistics.PerMinute)
initPeriodicStats(&statistics.PerHour)
initPeriodicStats(&statistics.PerDay)
+ statistics.Unlock()
}
func runStatsCollectors() {
@@ -121,10 +125,12 @@ func statsRotate(periodic *periodicStats, now time.Time, rotations int64) {
// called every second, accumulates stats for each second, minute, hour and day
func collectStats() {
now := time.Now()
+ statistics.Lock()
statsRotate(&statistics.PerSecond, now, int64(now.Sub(statistics.PerSecond.LastRotate)/time.Second))
statsRotate(&statistics.PerMinute, now, int64(now.Sub(statistics.PerMinute.LastRotate)/time.Minute))
statsRotate(&statistics.PerHour, now, int64(now.Sub(statistics.PerHour.LastRotate)/time.Hour))
statsRotate(&statistics.PerDay, now, int64(now.Sub(statistics.PerDay.LastRotate)/time.Hour/24))
+ statistics.Unlock()
// grab HTTP from prometheus
resp, err := client.Get("http://127.0.0.1:9153/metrics")
@@ -191,6 +197,7 @@ func collectStats() {
}
// calculate delta
+ statistics.Lock()
delta := calcDelta(entry, statistics.LastSeen)
// apply delta to second/minute/hour/day
@@ -201,6 +208,7 @@ func collectStats() {
// save last seen
statistics.LastSeen = entry
+ statistics.Unlock()
}
func calcDelta(current, seen statsEntry) statsEntry {
@@ -245,7 +253,9 @@ func loadStats() error {
func writeStats() error {
statsFile := filepath.Join(config.ourBinaryDir, "stats.json")
log.Printf("Writing JSON file: %s", statsFile)
+ statistics.RLock()
json, err := json.MarshalIndent(statistics, "", " ")
+ statistics.RUnlock()
if err != nil {
log.Printf("Couldn't generate JSON: %s", err)
return err