default to tunnel without ABISupport tag

When compiling a Linux binary without ABISupport, default to use the
tunnel.  The behaviour is expected in `podman-remote`.

Also set a default for the remote flag so `podman-remote` works OOB.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

cmd/podman/registry/config.go

@@ -22,6 +22,7 @@ const (
 var (
 	podmanOptions entities.PodmanConfig
 	podmanSync    sync.Once
+	abiSupport    = false
 )
 
 // PodmanConfig returns an entities.PodmanConfig built up from
@@ -39,23 +40,31 @@ func newPodmanConfig() {
 
 	var mode entities.EngineMode
 	switch runtime.GOOS {
-	case "darwin":
-		fallthrough
-	case "windows":
+	case "darwin", "windows":
 		mode = entities.TunnelMode
 	case "linux":
+		// Some linux clients might only be compiled without ABI
+		// support (e.g., podman-remote).
+		if abiSupport {
 			mode = entities.ABIMode
+		} else {
+			mode = entities.TunnelMode
+		}
 	default:
 		fmt.Fprintf(os.Stderr, "%s is not a supported OS", runtime.GOOS)
 		os.Exit(1)
 	}
 
+	// Check if need to fallback to the tunnel mode if --remote is used.
+	if abiSupport && mode == entities.ABIMode {
 		// cobra.Execute() may not be called yet, so we peek at os.Args.
 		for _, v := range os.Args {
 			// Prefix checking works because of how default EngineMode's
 			// have been defined.
 			if strings.HasPrefix(v, "--remote") {
 				mode = entities.TunnelMode
+				break
+			}
 		}
 	}
 

cmd/podman/registry/config_abi.go

@@ -0,0 +1,7 @@
+// +build ABISupport
+
+package registry
+
+func init() {
+	abiSupport = true
+}

cmd/podman/registry/config_tunnel.go

@@ -0,0 +1,7 @@
+// +build !ABISupport
+
+package registry
+
+func init() {
+	abiSupport = false
+}

cmd/podman/registry/registry.go

@@ -2,14 +2,18 @@ package registry
 
 import (
 	"context"
+	"path/filepath"
 
 	"github.com/containers/libpod/pkg/domain/entities"
 	"github.com/containers/libpod/pkg/domain/infra"
+	"github.com/containers/libpod/pkg/rootless"
+	"github.com/containers/libpod/pkg/util"
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 )
 
-// DefaultAPIAddress is the default address of the REST socket
-const DefaultAPIAddress = "unix:/run/podman/podman.sock"
+// DefaultRootAPIAddress is the default address of the REST socket
+const DefaultRootAPIAddress = "unix:/run/podman/podman.sock"
 
 // DefaultVarlinkAddress is the default address of the varlink socket
 const DefaultVarlinkAddress = "unix:/run/podman/io.podman"
@@ -98,3 +102,15 @@ func GetContextWithOptions() context.Context {
 func GetContext() context.Context {
 	return Context()
 }
+
+func DefaultAPIAddress() string {
+	if rootless.IsRootless() {
+		xdg, err := util.GetRuntimeDir()
+		if err != nil {
+			logrus.Warnf("Failed to get rootless runtime dir for DefaultAPIAddress: %s", err)
+			return DefaultRootAPIAddress
+		}
+		return "unix:" + filepath.Join(xdg, "podman", "podman.sock")
+	}
+	return DefaultRootAPIAddress
+}

cmd/podman/root.go

@@ -208,7 +208,7 @@ func syslogHook() {
 
 func rootFlags(opts *entities.PodmanConfig, flags *pflag.FlagSet) {
 	// V2 flags
-	flags.StringVarP(&opts.Uri, "remote", "r", "", "URL to access Podman service")
+	flags.StringVarP(&opts.Uri, "remote", "r", registry.DefaultAPIAddress(), "URL to access Podman service")
 	flags.StringSliceVar(&opts.Identities, "identity", []string{}, "path to SSH identity file")
 
 	cfg := opts.Config

cmd/podman/system/service.go

@@ -139,6 +139,6 @@ func resolveApiURI(_url []string) (string, error) {
 	case srvArgs.Varlink:
 		return registry.DefaultVarlinkAddress, nil
 	default:
-		return registry.DefaultAPIAddress, nil
+		return registry.DefaultRootAPIAddress, nil
 	}
 }