[tor-commits] [meek/master] Don't wait for handlers to finish after SIGTERM.

[dcf at torproject.org]

commit c7541223c704f76cb45a4e20bd20d963ea8d1fc7
Author: David Fifield <david at bamsoftware.com>
Date:   Wed Jan 16 22:52:51 2019 -0700

    Don't wait for handlers to finish after SIGTERM.
    
    The requirement to wait until handlers are finished, as well as the
    complicated signal counting logic, was removed from pt-spec.txt in 2014.
    
    https://bugs.torproject.org/26389
    
    Compare
    https://gitweb.torproject.org/pluggable-transports/goptlib.git/commit/?id=15f83653abbcced9003c96cc14edc5b2f82e0e0e
---
 meek-client/meek-client.go | 27 +++------------------------
 meek-server/meek-server.go | 25 ++-----------------------
 2 files changed, 5 insertions(+), 47 deletions(-)

diff --git a/meek-client/meek-client.go b/meek-client/meek-client.go
index 1b13f11..6059947 100644
--- a/meek-client/meek-client.go
+++ b/meek-client/meek-client.go
@@ -102,10 +102,6 @@ var options struct {
 	UseHelper bool
 }
 
-// When a connection handler starts, +1 is written to this channel; when it
-// ends, -1 is written.
-var handlerChan = make(chan int)
-
 // RequestInfo encapsulates all the configuration used for a request–response
 // roundtrip, including variables that may come from SOCKS args or from the
 // command line.
@@ -279,11 +275,6 @@ func genSessionID() string {
 
 // Callback for new SOCKS requests.
 func handler(conn *pt.SocksConn) error {
-	handlerChan <- 1
-	defer func() {
-		handlerChan <- -1
-	}()
-
 	defer conn.Close()
 	err := conn.Grant(&net.TCPAddr{IP: net.IPv4zero, Port: 0})
 	if err != nil {
@@ -473,8 +464,6 @@ func main() {
 	}
 	pt.CmethodsDone()
 
-	var numHandlers int = 0
-	var sig os.Signal
 	sigChan := make(chan os.Signal, 1)
 	signal.Notify(sigChan, syscall.SIGTERM)
 
@@ -488,23 +477,13 @@ func main() {
 		}()
 	}
 
-	// Keep track of handlers and wait for a signal.
-	sig = nil
-	for sig == nil {
-		select {
-		case n := <-handlerChan:
-			numHandlers += n
-		case sig = <-sigChan:
-			log.Printf("got signal %s", sig)
-		}
-	}
+	// Wait for a signal.
+	sig := <-sigChan
+	log.Printf("got signal %s", sig)
 
 	for _, ln := range listeners {
 		ln.Close()
 	}
-	for numHandlers > 0 {
-		numHandlers += <-handlerChan
-	}
 
 	log.Printf("done")
 }
diff --git a/meek-server/meek-server.go b/meek-server/meek-server.go
index 4676b47..42aab0a 100644
--- a/meek-server/meek-server.go
+++ b/meek-server/meek-server.go
@@ -70,10 +70,6 @@ const (
 
 var ptInfo pt.ServerInfo
 
-// When a connection handler starts, +1 is written to this channel; when it
-// ends, -1 is written.
-var handlerChan = make(chan int)
-
 func httpBadRequest(w http.ResponseWriter) {
 	http.Error(w, "Bad request.", http.StatusBadRequest)
 }
@@ -115,11 +111,6 @@ func NewState() *State {
 }
 
 func (state *State) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	handlerChan <- 1
-	defer func() {
-		handlerChan <- -1
-	}()
-
 	switch req.Method {
 	case "GET":
 		state.Get(w, req)
@@ -494,8 +485,6 @@ func main() {
 	}
 	pt.SmethodsDone()
 
-	var numHandlers int = 0
-	var sig os.Signal
 	sigChan := make(chan os.Signal, 1)
 	signal.Notify(sigChan, syscall.SIGTERM)
 
@@ -510,15 +499,8 @@ func main() {
 	}
 
 	// Keep track of handlers and wait for a signal.
-	sig = nil
-	for sig == nil {
-		select {
-		case n := <-handlerChan:
-			numHandlers += n
-		case sig = <-sigChan:
-			log.Printf("got signal %s", sig)
-		}
-	}
+	sig := <-sigChan
+	log.Printf("got signal %s", sig)
 
 	/*
 		// Not supported until go1.8.
@@ -526,9 +508,6 @@ func main() {
 			server.Close()
 		}
 	*/
-	for numHandlers > 0 {
-		numHandlers += <-handlerChan
-	}
 
 	log.Printf("done")
 }