Don't allow duplicate -v specifications for the same target

Addresses: #10618

Given that the user has no notification that they tried to bind mount
different directories on the same target in the container, this errors
out in that case, without changing the current code allowing for
--volumes-from to trump -v/VOLUME specifications.

Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)

daemon/volumes.go

@@ -158,6 +158,10 @@ func (container *Container) parseVolumeMountConfig() (map[string]*Mount, error)
 		if err != nil {
 			return nil, err
 		}
+		// Check if a bind mount has already been specified for the same container path
+		if m, exists := mounts[mountToPath]; exists {
+			return nil, fmt.Errorf("Duplicate volume %q: %q already in use, mounted from %q", path, mountToPath, m.volume.Path)
+		}
 		// Check if a volume already exists for this and use it
 		vol, err := container.daemon.volumes.FindOrCreateVolume(path, writable)
 		if err != nil {

integration-cli/docker_cli_run_test.go

@@ -493,6 +493,21 @@ func TestVolumesFromGetsProperMode(t *testing.T) {
 	logDone("run - volumes from ignores `rw` if inherrited volume is `ro`")
 }
 
+// Test for GH#10618
+func TestRunNoDupVolumes(t *testing.T) {
+	cmd := exec.Command(dockerBinary, "run", "-v", "/etc:/someplace", "-v", "/usr/lib:/someplace", "busybox", "echo", "hi")
+	if out, _, err := runCommandWithOutput(cmd); err == nil {
+		t.Fatal("Expected error about duplicate volume definitions")
+	} else {
+		if !strings.Contains(out, "Duplicate volume") {
+			t.Fatalf("Expected 'duplicate volume' error, got %v", err)
+		}
+	}
+	deleteAllContainers()
+
+	logDone("run - don't allow multiple (bind) volumes on the same container target")
+}
+
 // Test for #1351
 func TestRunApplyVolumesFromBeforeVolumes(t *testing.T) {
 	cmd := exec.Command(dockerBinary, "run", "--name", "parent", "-v", "/test", "busybox", "touch", "/test/foo")