pkg/signal: ignore SIGTOP for signal proxy

It makes no sense to forward it, SIGSTOP cannot be handled by
userspace (like SIGKILL) and it didn't do anything before so this just
makes it more explicit.

Signed-off-by: Paul Holzinger <[email protected]>

Author: Luap99

pkg/signal/signal_linux.go

@@ -94,5 +94,11 @@ 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
+	// SIGSTOP cannot be ignored/forwarded by userspace.
+	switch s {
+	case syscall.SIGCHLD, syscall.SIGPIPE, syscall.SIGURG, syscall.SIGSTOP:
+		return true
+	default:
+		return false
+	}
 }

pkg/signal/signal_linux_mipsx.go

@@ -94,5 +94,11 @@ 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
+	// SIGSTOP cannot be ignored/forwarded by userspace.
+	switch s {
+	case syscall.SIGCHLD, syscall.SIGPIPE, syscall.SIGURG, syscall.SIGSTOP:
+		return true
+	default:
+		return false
+	}
 }

pkg/signal/signal_unix.go

@@ -92,5 +92,11 @@ 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
+	// SIGSTOP cannot be ignored/forwarded by userspace.
+	switch s {
+	case syscall.SIGCHLD, syscall.SIGPIPE, syscall.SIGURG, syscall.SIGSTOP:
+		return true
+	default:
+		return false
+	}
 }