Allow custom priv key bytes on all platforms

config/cfg.go

@@ -0,0 +1,83 @@
+package config
+
+import (
+	"encoding/json"
+	"errors"
+	"os"
+	"reflect"
+
+	"github.com/rwinkhart/libmutton/global"
+)
+
+type CfgT struct {
+	Libmutton struct {
+		OfflineMode      *bool   `json:"offlineMode"`
+		SSHUser          *string `json:"sshUser"`
+		SSHIP            *string `json:"sshIP"`
+		SSHPort          *string `json:"sshPort"`
+		SSHEntryRootPath *string `json:"sshEntryRootPath"`
+		SSHAgeDirPath    *string `json:"sshAgeDirPath"`
+		SSHKeyPath       *string `json:"sshKeyPath"`
+		SSHKeyProtected  *bool   `json:"sshKeyProtected"`
+		SSHIsWindows     *bool   `json:"sshIsWindows"`
+	} `json:"libmutton"`
+	ClientSpecific *map[string]any `json:"clientSpecific"`
+}
+
+// Load loads libmuttoncfg.json and returns the configuration.
+func Load() (*CfgT, error) {
+	cfgBytes, err := os.ReadFile(global.CfgPath)
+	if err != nil {
+		return nil, errors.New("unable to load libmuttoncfg.json: " + err.Error())
+	}
+	var cfg CfgT
+	if err = json.Unmarshal(cfgBytes, &cfg); err != nil {
+		return nil, errors.New("unable to unmarshal libmuttoncfg.json: " + err.Error())
+	}
+	return &cfg, nil
+}
+
+// Write writes cfg to libmuttoncfg.json.
+// If used in append mode, any nil values in the
+// input cfg will be substituted with the existing values.
+func Write(cfg *CfgT, appendMode bool) error {
+start:
+	if appendMode {
+		// check if any fields are nil
+		var hasNilFields bool
+		cfgValue := reflect.ValueOf(&cfg.Libmutton).Elem()
+		for i := 0; i < cfgValue.NumField(); i++ {
+			field := cfgValue.Field(i)
+			if field.IsNil() {
+				hasNilFields = true
+				break
+			}
+		}
+
+		// load old cfg and copy nil fields
+		if hasNilFields {
+			oldCfg, err := Load()
+			if err != nil {
+				// failed to load config, leave append mode
+				appendMode = false
+				goto start
+			}
+			oldValue := reflect.ValueOf(&oldCfg.Libmutton).Elem()
+			for i := 0; i < cfgValue.NumField(); i++ {
+				field := cfgValue.Field(i)
+				if field.IsNil() {
+					field.Set(oldValue.Field(i))
+				}
+			}
+		}
+	}
+	cfgBytes, err := json.MarshalIndent(cfg, "", "  ")
+	if err != nil {
+		return errors.New("unable to marshal new/updated cfg: " + err.Error())
+	}
+	if err = os.WriteFile(global.CfgPath, cfgBytes, 0600); err != nil {
+		return errors.New("unable to write new/updated cfg to libmuttoncfg.json: " + err.Error())
+	}
+
+	return nil
+}