pkg/signal: move Trap() to cmd/dockerd

It's the only location where this is used, and it's quite specific
to dockerd (not really a reusable function for external use), so
moving it into that package.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cmd/dockerd/daemon.go

@@ -32,6 +32,7 @@ import (
 	buildkit "github.com/docker/docker/builder/builder-next"
 	"github.com/docker/docker/builder/dockerfile"
 	"github.com/docker/docker/cli/debug"
+	"github.com/docker/docker/cmd/dockerd/trap"
 	"github.com/docker/docker/daemon"
 	"github.com/docker/docker/daemon/cluster"
 	"github.com/docker/docker/daemon/config"
@@ -44,7 +45,6 @@ import (
 	"github.com/docker/docker/pkg/jsonmessage"
 	"github.com/docker/docker/pkg/pidfile"
 	"github.com/docker/docker/pkg/plugingetter"
-	"github.com/docker/docker/pkg/signal"
 	"github.com/docker/docker/pkg/sysinfo"
 	"github.com/docker/docker/pkg/system"
 	"github.com/docker/docker/plugin"
@@ -183,7 +183,7 @@ func (cli *DaemonCli) start(opts *daemonOptions) (err error) {
 	stopc := make(chan bool)
 	defer close(stopc)
 
-	signal.Trap(func() {
+	trap.Trap(func() {
 		cli.stop()
 		<-stopc // wait for daemonCli.start() to return
 	}, logrus.StandardLogger())

cmd/dockerd/trap/testfiles/main.go

@@ -5,7 +5,7 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/docker/docker/pkg/signal"
+	"github.com/docker/docker/cmd/dockerd/trap"
 	"github.com/sirupsen/logrus"
 )
 
@@ -15,7 +15,7 @@ func main() {
 		"QUIT": syscall.SIGQUIT,
 		"INT":  os.Interrupt,
 	}
-	signal.Trap(func() {
+	trap.Trap(func() {
 		time.Sleep(time.Second)
 		os.Exit(99)
 	}, logrus.StandardLogger())

cmd/dockerd/trap/trap.go

@@ -1,4 +1,4 @@
-package signal // import "github.com/docker/docker/pkg/signal"
+package trap // import "github.com/docker/docker/cmd/dockerd/trap"
 
 import (
 	"fmt"

cmd/dockerd/trap/trap_linux_test.go

@@ -1,6 +1,6 @@
 // +build linux
 
-package signal // import "github.com/docker/docker/pkg/signal"
+package trap // import "github.com/docker/docker/cmd/dockerd/trap"
 
 import (
 	"io/ioutil"