From 57a9fbf3932ca5bd726f7381b92c106a68b50b89 Mon Sep 17 00:00:00 2001
From: Christopher Young <cyoung@gmail.com>
Date: Tue, 19 Jan 2016 10:40:40 -0500
Subject: [PATCH] Catch SIGINT and SIGTERM - shutdown SDR functions.

Fixes #204.
---
 main/gen_gdl90.go | 17 +++++++++++++++++
 main/sdr.go       | 22 ++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/main/gen_gdl90.go b/main/gen_gdl90.go
index a9a443a3..588e1aff 100644
--- a/main/gen_gdl90.go
+++ b/main/gen_gdl90.go
@@ -21,9 +21,11 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
+	"os/signal"
 	"runtime"
 	"strconv"
 	"strings"
+	"syscall"
 	"time"
 
 	humanize "github.com/dustin/go-humanize"
@@ -1200,8 +1202,23 @@ func openReplayFile(fn string) ReadCloser {
 }
 
 var stratuxClock *monotonic
+var sigs = make(chan os.Signal, 1) // Signal catch channel (shutdown).
+
+// Graceful shutdown.
+func signalWatcher() {
+	sig := <-sigs
+	log.Printf("signal caught: %s - shutting down.\n", sig.String())
+	// Shut down SDRs.
+	sdrKill()
+	//TODO: Any other graceful shutdown functions.
+	os.Exit(1)
+}
 
 func main() {
+	// Catch signals for graceful shutdown.
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+	go signalWatcher()
+
 	stratuxClock = NewMonotonic() // Start our "stratux clock".
 
 	//	replayESFilename := flag.String("eslog", "none", "ES Log filename")
diff --git a/main/sdr.go b/main/sdr.go
index 79d71fa7..f41fa1a4 100644
--- a/main/sdr.go
+++ b/main/sdr.go
@@ -284,6 +284,17 @@ func (e *ES) shutdown() {
 
 var devMap = map[int]string{0: "", 1: ""}
 
+var sdrShutdown bool
+
+func sdrKill() {
+	// Send signal to shutdown to sdrWatcher().
+	sdrShutdown = true
+	// Spin until all devices have been de-initialized.
+	for UATDev != nil || ESDev != nil {
+		time.Sleep(1 * time.Second)
+	}
+}
+
 // Watch for config/device changes.
 func sdrWatcher() {
 	stopCheckingUATUntil := time.Time{}
@@ -292,6 +303,17 @@ func sdrWatcher() {
 
 	for {
 		time.Sleep(1 * time.Second)
+		if sdrShutdown {
+			if UATDev != nil {
+				UATDev.shutdown()
+				UATDev = nil
+			}
+			if ESDev != nil {
+				ESDev.shutdown()
+				ESDev = nil
+			}
+			return
+		}
 		count := rtl.GetDeviceCount()
 		atomic.StoreUint32(&globalStatus.Devices, uint32(count))
 		// log.Println("DeviceCount...", count)