commit b9cc54b3b7dbd76d85613f0f478c95b193441564 Author: Cecylia Bocovich <cohosh@torproject.org> Date: Thu Oct 29 16:21:37 2020 -0400 Send shutdown signal to shutdown open connections Normally all dangling goroutines are terminated when the main function exits. However, for projects that use a patched version of snowflake as a library, these goroutines continued running as long as the main function had not yet terminated. This commit has all open SOCKS connections close after receiving a shutdown signal. --- client/snowflake.go | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-) diff --git a/client/snowflake.go b/client/snowflake.go index a1b97fa..a1a679e 100644 --- a/client/snowflake.go +++ b/client/snowflake.go @@ -27,7 +27,7 @@ const ( ) // Accept local SOCKS connections and pass them to the handler. -func socksAcceptLoop(ln *pt.SocksListener, tongue sf.Tongue) { +func socksAcceptLoop(ln *pt.SocksListener, tongue sf.Tongue, shutdown chan struct{}) { defer ln.Close() for { conn, err := ln.AcceptSocks() @@ -48,11 +48,23 @@ func socksAcceptLoop(ln *pt.SocksListener, tongue sf.Tongue) { return } - err = sf.Handler(conn, tongue) - if err != nil { - log.Printf("handler error: %s", err) + handler := make(chan struct{}) + go func() { + err = sf.Handler(conn, tongue) + if err != nil { + log.Printf("handler error: %s", err) + } + close(handler) return + + }() + select { + case <-shutdown: + log.Println("Received shutdown signal") + case <-handler: + log.Println("Handler ended") } + return }() } } @@ -160,6 +172,7 @@ func main() { os.Exit(1) } listeners := make([]net.Listener, 0) + shutdown := make(chan struct{}) for _, methodName := range ptInfo.MethodNames { switch methodName { case "snowflake": @@ -170,7 +183,7 @@ func main() { break } log.Printf("Started SOCKS listener at %v.", ln.Addr()) - go socksAcceptLoop(ln, dialer) + go socksAcceptLoop(ln, dialer, shutdown) pt.Cmethod(methodName, ln.Version(), ln.Addr()) listeners = append(listeners, ln) default: @@ -196,11 +209,13 @@ func main() { // Wait for a signal. <-sigChan + log.Println("stopping snowflake") // Signal received, shut down. for _, ln := range listeners { ln.Close() } + close(shutdown) log.Println("snowflake is done.") }