v2podman attach and exec

add the ability to attach to a running container.  the tunnel side of this is not enabled yet as we have work on the endpoints and plumbing to do yet.

add the ability to exec a command in a running container.  the tunnel side is also being deferred for same reason.

Signed-off-by: Brent Baude <bbaude@redhat.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/pkg/domain/infra/abi/terminal/sigproxy_linux.go b/pkg/domain/infra/abi/terminal/sigproxy_linux.go
new file mode 100644
index 000000000..d7f5853d8
--- /dev/null
+++ b/pkg/domain/infra/abi/terminal/sigproxy_linux.go
@@ -0,0 +1,47 @@
+// +build ABISupport
+
+package terminal
+
+import (
+	"os"
+	"syscall"
+
+	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/pkg/signal"
+	"github.com/sirupsen/logrus"
+)
+
+// ProxySignals ...
+func ProxySignals(ctr *libpod.Container) {
+	sigBuffer := make(chan os.Signal, 128)
+	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/libpod/issues/5483
+			if s == syscall.SIGCHLD || s == syscall.SIGPIPE || s == syscall.SIGURG {
+				continue
+			}
+
+			if err := ctr.Kill(uint(s.(syscall.Signal))); err != nil {
+				// If the container dies, and we find out here,
+				// we need to forward that one signal to
+				// ourselves so that it is not lost, and then
+				// we terminate the proxy and let the defaults
+				// play out.
+				logrus.Errorf("Error forwarding signal %d to container %s: %v", s, ctr.ID(), err)
+				signal.StopCatch(sigBuffer)
+				if err := syscall.Kill(syscall.Getpid(), s.(syscall.Signal)); err != nil {
+					logrus.Errorf("failed to kill pid %d", syscall.Getpid())
+				}
+				return
+			}
+		}
+	}()
+}