Add support to sig-proxy for podman-remote

Signed-off-by: Boaz Shuster <boaz.shuster.github@gmail.com>

pkg/domain/infra/abi/terminal/sigproxy_commn.go

@@ -15,33 +15,25 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-// Make sure the signal buffer is sufficiently big.
-// runc is using the same value.
-const signalBufferSize = 2048
-
 // ProxySignals ...
 func ProxySignals(ctr *libpod.Container) {
 	// Stop catching the shutdown signals (SIGINT, SIGTERM) - they're going
 	// to the container now.
 	shutdown.Stop() //nolint: errcheck
 
-	sigBuffer := make(chan os.Signal, signalBufferSize)
+	sigBuffer := make(chan os.Signal, signal.SignalBufferSize)
 	signal.CatchAll(sigBuffer)
 
 	logrus.Debugf("Enabling signal proxying")
 
 	go func() {
 		for s := range sigBuffer {
-			// Ignore SIGCHLD and SIGPIPE - these are mostly likely
-			// intended for the podman command itself.
-			// SIGURG was added because of golang 1.14 and its preemptive changes
-			// causing more signals to "show up".
-			// https://github.com/containers/podman/issues/5483
-			if s == syscall.SIGCHLD || s == syscall.SIGPIPE || s == syscall.SIGURG {
+			syscallSignal := s.(syscall.Signal)
+			if signal.IsSignalIgnoredBySigProxy(syscallSignal) {
 				continue
 			}
 
-			if err := ctr.Kill(uint(s.(syscall.Signal))); err != nil {
+			if err := ctr.Kill(uint(syscallSignal)); err != nil {
 				if errors.Is(err, define.ErrCtrStateInvalid) {
 					logrus.Infof("Ceasing signal forwarding to container %s as it has stopped", ctr.ID())
 				} else {

pkg/domain/infra/tunnel/containers.go

@@ -825,6 +825,13 @@ func (ic *ContainerEngine) ContainerRun(ctx context.Context, opts entities.Conta
 	}
 
 	// Attach
+	if opts.SigProxy {
+		remoteProxySignals(con.ID, func(signal string) error {
+			killOpts := entities.KillOptions{All: false, Latest: false, Signal: signal}
+			_, err := ic.ContainerKill(ctx, []string{con.ID}, killOpts)
+			return err
+		})
+	}
 	if err := startAndAttach(ic, con.ID, &opts.DetachKeys, opts.InputStream, opts.OutputStream, opts.ErrorStream); err != nil {
 		if err == define.ErrDetach {
 			return &report, nil

pkg/domain/infra/tunnel/runtime.go

@@ -2,6 +2,12 @@ package tunnel
 
 import (
 	"context"
+	"os"
+	"syscall"
+
+	"github.com/containers/podman/v4/libpod/define"
+	"github.com/containers/podman/v4/pkg/signal"
+	"github.com/sirupsen/logrus"
 )
 
 // Image-related runtime using an ssh-tunnel to utilize Podman service
@@ -18,3 +24,28 @@ type ContainerEngine struct {
 type SystemEngine struct {
 	ClientCtx context.Context
 }
+
+func remoteProxySignals(ctrID string, killFunc func(string) error) {
+	sigBuffer := make(chan os.Signal, signal.SignalBufferSize)
+	signal.CatchAll(sigBuffer)
+
+	logrus.Debugf("Enabling signal proxying")
+
+	go func() {
+		for s := range sigBuffer {
+			syscallSignal := s.(syscall.Signal)
+			if signal.IsSignalIgnoredBySigProxy(syscallSignal) {
+				continue
+			}
+			signalName, err := signal.ParseSysSignalToName(syscallSignal)
+			if err != nil {
+				logrus.Infof("Ceasing signal %v forwarding to container %s as it has stopped: %s", s, ctrID, err)
+			}
+			if err := killFunc(signalName); err != nil {
+				if err.Error() == define.ErrCtrStateInvalid.Error() {
+					logrus.Debugf("Ceasing signal %q forwarding to container %s as it has stopped", signalName, ctrID)
+				}
+			}
+		}
+	}()
+}

pkg/signal/signal_common.go

@@ -9,6 +9,10 @@ import (
 	"syscall"
 )
 
+// Make sure the signal buffer is sufficiently big.
+// runc is using the same value.
+const SignalBufferSize = 2048
+
 // ParseSignal translates a string to a valid syscall signal.
 // It returns an error if the signal map doesn't include the given signal.
 func ParseSignal(rawSignal string) (syscall.Signal, error) {
@@ -56,3 +60,14 @@ func StopCatch(sigc chan os.Signal) {
 	signal.Stop(sigc)
 	close(sigc)
 }
+
+// ParseSysSignalToName translates syscall.Signal to its name in the operating system.
+// For example, syscall.Signal(9) will return "KILL" on Linux system.
+func ParseSysSignalToName(s syscall.Signal) (string, error) {
+	for k, v := range SignalMap {
+		if v == s {
+			return k, nil
+		}
+	}
+	return "", fmt.Errorf("unknown syscall signal: %s", s)
+}

pkg/signal/signal_common_test.go

@@ -118,3 +118,52 @@ func TestParseSignalNameOrNumber(t *testing.T) {
 		})
 	}
 }
+
+func TestParseSysSignalToName(t *testing.T) {
+	type args struct {
+		signal syscall.Signal
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    string
+		wantErr bool
+	}{
+		{
+			name: "Kill should work",
+			args: args{
+				signal: syscall.SIGKILL,
+			},
+			want:    "KILL",
+			wantErr: false,
+		},
+		{
+			name: "Non-defined signal number should not work",
+			args: args{
+				signal: 923,
+			},
+			want:    "",
+			wantErr: true,
+		},
+		{
+			name: "garbage should fail",
+			args: args{
+				signal: -1,
+			},
+			want:    "",
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ParseSysSignalToName(tt.args.signal)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ParseSysSignalToName() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("ParseSysSignalToName() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

pkg/signal/signal_linux.go

@@ -89,3 +89,11 @@ var SignalMap = map[string]syscall.Signal{
 	"RTMAX-1":  sigrtmax - 1,
 	"RTMAX":    sigrtmax,
 }
+
+// IsSignalIgnoredBySigProxy determines whether sig-proxy should ignore syscall signal
+func IsSignalIgnoredBySigProxy(s syscall.Signal) bool {
+	// Ignore SIGCHLD and SIGPIPE - these are most likely intended for the podman command itself.
+	// SIGURG was added because of golang 1.14 and its preemptive changes causing more signals to "show up".
+	// https://github.com/containers/podman/issues/5483
+	return s == syscall.SIGCHLD || s == syscall.SIGPIPE || s == syscall.SIGURG
+}

pkg/signal/signal_linux_mipsx.go

@@ -90,3 +90,11 @@ var SignalMap = map[string]syscall.Signal{
 	"RTMAX-1":  sigrtmax - 1,
 	"RTMAX":    sigrtmax,
 }
+
+// IsSignalIgnoredBySigProxy determines whether sig-proxy should ignore syscall signal
+func IsSignalIgnoredBySigProxy(s syscall.Signal) bool {
+	// Ignore SIGCHLD and SIGPIPE - these are most likely intended for the podman command itself.
+	// SIGURG was added because of golang 1.14 and its preemptive changes causing more signals to "show up".
+	// https://github.com/containers/podman/issues/5483
+	return s == syscall.SIGCHLD || s == syscall.SIGPIPE || s == syscall.SIGURG
+}

pkg/signal/signal_unix.go

@@ -87,3 +87,11 @@ var SignalMap = map[string]syscall.Signal{
 	"RTMAX-1":  sigrtmax - 1,
 	"RTMAX":    sigrtmax,
 }
+
+// IsSignalIgnoredBySigProxy determines whether sig-proxy should ignore syscall signal
+func IsSignalIgnoredBySigProxy(s syscall.Signal) bool {
+	// Ignore SIGCHLD and SIGPIPE - these are most likely intended for the podman command itself.
+	// SIGURG was added because of golang 1.14 and its preemptive changes causing more signals to "show up".
+	// https://github.com/containers/podman/issues/5483
+	return s == syscall.SIGCHLD || s == syscall.SIGPIPE || s == syscall.SIGURG
+}

pkg/signal/signal_unsupported.go

@@ -87,3 +87,9 @@ var SignalMap = map[string]syscall.Signal{
 	"RTMAX-1":  sigrtmax - 1,
 	"RTMAX":    sigrtmax,
 }
+
+// IsSignalIgnoredBySigProxy determines whether to sig-proxy should ignore syscall signal
+// keep the container running or not. In unsupported OS this should not ignore any syscall signal.
+func IsSignalIgnoredBySigProxy(s syscall.Signal) bool {
+	return false
+}

test/system/032-sig-proxy.bats

@@ -0,0 +1,43 @@
+#!/usr/bin/env bats
+
+load helpers
+
+@test "podman sigkill" {
+    $PODMAN run -i --name foo $IMAGE sh -c 'trap "echo BYE;exit 0" INT;echo READY;while :;do sleep 0.1;done' &
+    local kidpid=$!
+
+    # Wait for container to appear
+    local timeout=5
+    while :;do
+          sleep 0.5
+          run_podman '?' container exists foo
+          if [[ $status -eq 0 ]]; then
+              break
+          fi
+          timeout=$((timeout - 1))
+          if [[ $timeout -eq 0 ]]; then
+              die "Timed out waiting for container to start"
+          fi
+    done
+
+    wait_for_ready foo
+
+    # Signal, and wait for container to exit
+    kill -INT $kidpid
+    local timeout=5
+    while :;do
+          sleep 0.5
+          run_podman logs foo
+          if [[ "$output" =~ BYE ]]; then
+              break
+          fi
+          timeout=$((timeout - 1))
+          if [[ $timeout -eq 0 ]]; then
+              die "Timed out waiting for BYE from container"
+          fi
+    done
+
+    run_podman rm -f -t0 foo
+}
+
+# vim: filetype=sh