Enable masking stop signals within container creation

Expand the use of the Shutdown package such that we now use it
to handle signals any time we run Libpod. From there, add code to
container creation to use the Inhibit function to prevent a
shutdown from occuring during the critical parts of container
creation.

We also need to turn off signal handling when --sig-proxy is
invoked - we don't want to catch the signals ourselves then, but
instead to forward them into the container via the existing
sig-proxy handler.

Fixes #7941

Signed-off-by: Matthew Heon <mheon@redhat.com>

2 files changed, 9 insertions, 6 deletions

diff --git a/pkg/api/server/server.go b/pkg/api/server/server.go
index cc5b45a65..24ad1874b 100644
--- a/pkg/api/server/server.go
+++ b/pkg/api/server/server.go
@@ -190,6 +190,9 @@ func (s *APIServer) Serve() error {
 	}); err != nil {
 		return err
 	}
+	// Unregister the libpod handler, which just calls exit(1).
+	// Ignore errors if it doesn't exist.
+	_ = shutdown.Unregister("libpod")
 
 	errChan := make(chan error, 1)
 
@@ -226,12 +229,7 @@ func (s *APIServer) Serve() error {
 		errChan <- nil
 	}()
 
-	select {
-	case err := <-errChan:
-		return err
-	}
-
-	return nil
+	return <-errChan
 }
 
 // Shutdown is a clean shutdown waiting on existing clients
diff --git a/pkg/domain/infra/abi/terminal/sigproxy_linux.go b/pkg/domain/infra/abi/terminal/sigproxy_linux.go
index f484e926c..0c586cf5c 100644
--- a/pkg/domain/infra/abi/terminal/sigproxy_linux.go
+++ b/pkg/domain/infra/abi/terminal/sigproxy_linux.go
@@ -5,12 +5,17 @@ import (
 	"syscall"
 
 	"github.com/containers/podman/v2/libpod"
+	"github.com/containers/podman/v2/libpod/shutdown"
 	"github.com/containers/podman/v2/pkg/signal"
 	"github.com/sirupsen/logrus"
 )
 
 // ProxySignals ...
 func ProxySignals(ctr *libpod.Container) {
+	// Stop catching the shutdown signals (SIGINT, SIGTERM) - they're going
+	// to the container now.
+	shutdown.Stop()
+
 	sigBuffer := make(chan os.Signal, 128)
 	signal.CatchAll(sigBuffer)