osbuild2: add support for org.osbuild.modprobe stage

Add support for the `org.osbuild.modprobe` osbuild stage [1], which
allows one to configure modprobe by creating configuration files.

Add unit test cases for the newly added stage.

[1] https://github.com/osbuild/osbuild/pull/670

Signed-off-by: Tomas Hozza <thozza@redhat.com>

internal/osbuild2/modprobe_stage.go

@@ -0,0 +1,91 @@
+package osbuild2
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+type ModprobeStageOptions struct {
+	ConfigFiles map[string]ModprobeConfigCmdList `json:"configuration_files,omitempty"`
+}
+
+func (ModprobeStageOptions) isStageOptions() {}
+
+func NewModprobeStage(options *ModprobeStageOptions) *Stage {
+	return &Stage{
+		Type:    "org.osbuild.modprobe",
+		Options: options,
+	}
+}
+
+type ModprobeConfigCmd interface {
+	isModprobeConfigCmd()
+}
+
+// ModprobeConfigCmdList represents a modprobe configuration file, which contains
+// a list of commands.
+type ModprobeConfigCmdList []ModprobeConfigCmd
+
+func (configFile *ModprobeConfigCmdList) UnmarshalJSON(data []byte) error {
+	var rawConfigFile []interface{}
+
+	if err := json.Unmarshal(data, &rawConfigFile); err != nil {
+		return err
+	}
+
+	for _, rawConfigCmd := range rawConfigFile {
+		var modprobeCmd ModprobeConfigCmd
+
+		// The command object structure depends on the value of "command"
+		// item, therefore make no assumptions on the structure.
+		configCmdMap, ok := rawConfigCmd.(map[string]interface{})
+		if !ok {
+			return fmt.Errorf("unexpected modprobe configuration file format")
+		}
+		command, ok := configCmdMap["command"].(string)
+		if !ok {
+			return fmt.Errorf("'command' item should be string, not %T", configCmdMap["command"])
+		}
+
+		switch command {
+		case "blacklist":
+			modulename, ok := configCmdMap["modulename"].(string)
+			if !ok {
+				return fmt.Errorf("'modulename' item should be string, not %T", configCmdMap["modulename"])
+			}
+			modprobeCmd = NewModprobeConfigCmdBlacklist(modulename)
+		default:
+			return fmt.Errorf("unexpected modprobe command: %s", command)
+		}
+
+		*configFile = append(*configFile, modprobeCmd)
+	}
+
+	return nil
+}
+
+func (o ModprobeConfigCmdList) MarshalJSON() ([]byte, error) {
+	if len(o) == 0 {
+		return nil, fmt.Errorf("at least one modprobe command must be specified for a configuration file")
+	}
+	var configList []ModprobeConfigCmd = o
+	return json.Marshal(configList)
+}
+
+// ModprobeConfigCmdBlacklist represents the 'blacklist' command in the
+// modprobe configuration.
+type ModprobeConfigCmdBlacklist struct {
+	Command    string `json:"command"`
+	Modulename string `json:"modulename"`
+}
+
+func (ModprobeConfigCmdBlacklist) isModprobeConfigCmd() {}
+
+// NewModprobeConfigCmdBlacklist creates a new instance of ModprobeConfigCmdBlacklist
+// for the provided modulename.
+func NewModprobeConfigCmdBlacklist(modulename string) *ModprobeConfigCmdBlacklist {
+	return &ModprobeConfigCmdBlacklist{
+		Command:    "blacklist",
+		Modulename: modulename,
+	}
+}

internal/osbuild2/modprobe_stage_test.go

@@ -0,0 +1,39 @@
+package osbuild2
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewModprobeStage(t *testing.T) {
+	expectedStage := &Stage{
+		Type:    "org.osbuild.modprobe",
+		Options: &ModprobeStageOptions{},
+	}
+	actualStage := NewModprobeStage(&ModprobeStageOptions{})
+	assert.Equal(t, expectedStage, actualStage)
+}
+
+func TestModprobeStage_MarshalJSON_Invalid(t *testing.T) {
+	tests := []struct {
+		name    string
+		options ModprobeStageOptions
+	}{
+		{
+			name: "no-commands",
+			options: ModprobeStageOptions{
+				ConfigFiles: map[string]ModprobeConfigCmdList{
+					"disallow-modules.conf": {},
+				},
+			},
+		},
+	}
+	for idx, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotBytes, err := json.Marshal(tt.options)
+			assert.NotNilf(t, err, "json.Marshal() didn't return an error, but: %s [idx: %d]", string(gotBytes), idx)
+		})
+	}
+}

internal/osbuild2/stage.go

@@ -89,6 +89,8 @@ func (stage *Stage) UnmarshalJSON(data []byte) error {
 		options = new(ChronyStageOptions)
 	case "org.osbuild.keymap":
 		options = new(KeymapStageOptions)
+	case "org.osbuild.modprobe":
+		options = new(ModprobeStageOptions)
 	case "org.osbuild.firewall":
 		options = new(FirewallStageOptions)
 	case "org.osbuild.rhsm":

internal/osbuild2/stage_test.go

@@ -162,6 +162,45 @@ func TestStage_UnmarshalJSON(t *testing.T) {
 				data: []byte(`{"type":"org.osbuild.keymap","options":{"keymap":""}}`),
 			},
 		},
+		{
+			name: "modprobe",
+			fields: fields{
+				Type:    "org.osbuild.modprobe",
+				Options: &ModprobeStageOptions{},
+			},
+			args: args{
+				data: []byte(`{"type":"org.osbuild.modprobe","options":{}}`),
+			},
+		},
+		{
+			name: "modprobe-data",
+			fields: fields{
+				Type: "org.osbuild.modprobe",
+				Options: &ModprobeStageOptions{
+					ConfigFiles: map[string]ModprobeConfigCmdList{
+						"disallow-modules.conf": {
+							&ModprobeConfigCmdBlacklist{
+								Command:    "blacklist",
+								Modulename: "nouveau",
+							},
+							&ModprobeConfigCmdBlacklist{
+								Command:    "blacklist",
+								Modulename: "floppy",
+							},
+						},
+						"disallow-additional-modules.conf": {
+							&ModprobeConfigCmdBlacklist{
+								Command:    "blacklist",
+								Modulename: "my-module",
+							},
+						},
+					},
+				},
+			},
+			args: args{
+				data: []byte(`{"type":"org.osbuild.modprobe","options":{"configuration_files":{"disallow-additional-modules.conf":[{"command":"blacklist","modulename":"my-module"}],"disallow-modules.conf":[{"command":"blacklist","modulename":"nouveau"},{"command":"blacklist","modulename":"floppy"}]}}}`),
+			},
+		},
 		{
 			name: "locale",
 			fields: fields{