From 392c7b6ee19ed38650fc9d7f4f3750d965e94da5 Mon Sep 17 00:00:00 2001
From: Simon Zolin <s.zolin@adguard.com>
Date: Wed, 24 Apr 2019 15:02:41 +0300
Subject: [PATCH] - control: fix race in /control/version.json handler
---
control.go | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/control.go b/control.go
index 35214d82..036e44a8 100644
--- a/control.go
+++ b/control.go
@@ -559,11 +559,17 @@ func checkDNS(input string, bootstrap []string) error {
func handleGetVersionJSON(w http.ResponseWriter, r *http.Request) {
log.Tracef("%s %v", r.Method, r.URL)
+
now := time.Now()
- if now.Sub(versionCheckLastTime) <= versionCheckPeriod && len(versionCheckJSON) != 0 {
+ controlLock.Lock()
+ cached := now.Sub(versionCheckLastTime) <= versionCheckPeriod && len(versionCheckJSON) != 0
+ data := versionCheckJSON
+ controlLock.Unlock()
+
+ if cached {
// return cached copy
w.Header().Set("Content-Type", "application/json")
- w.Write(versionCheckJSON)
+ w.Write(data)
return
}
@@ -589,8 +595,10 @@ func handleGetVersionJSON(w http.ResponseWriter, r *http.Request) {
httpError(w, http.StatusInternalServerError, "Couldn't write body: %s", err)
}
+ controlLock.Lock()
versionCheckLastTime = now
versionCheckJSON = body
+ controlLock.Unlock()
}
// ---------