core: Add support for removing users from the system

Functionality primarily added to remove the accidentally added
sambashares user as part of a typical samba update.

core/context.go

@@ -137,7 +137,7 @@ func (c *Context) CreateGroup(name string, id string) error {
 	return nil
 }
 
-// DeleteGroup deletes a preexisting group with the given name and ID
+// DeleteGroup deletes a preexisting group with the given name
 func (c *Context) DeleteGroup(name string) error {
 	cmd := exec.Command("groupdel", name)
 	if err := cmd.Run(); err != nil {
@@ -154,6 +154,21 @@ func (c *Context) DeleteGroup(name string) error {
 	return nil
 }
 
+// DeleteUser deletes a preexisting user with the given user
+func (c *Context) DeleteUser(user *User) (ran bool, err error) {
+	cmd := exec.Command("userdel", "-r", "-f", user.Name)
+	ran = true
+	if err := cmd.Run(); err == nil {
+		// remove user from c.users
+		for i, v := range c.users {
+			if v.Name == user.Name {
+				c.users = append(c.users[0:i], c.users[i+1:]...)
+			}
+		}
+	}
+	return
+}
+
 // UpdateGroupID finds a group with the given name and changes its ID to the given ID
 func (c *Context) UpdateGroupID(name string, id string) error {
 	cmd := exec.Command("groupmod", "-g", id, name)

core/migration.go

@@ -34,6 +34,7 @@ type Migration struct {
 	UpdateGroup []*UpdateGroup `toml:"group-update"`
 	RemoveUsers []*RemoveUsers `toml:"users-remove"`
 	RemoveGroup []*RemoveGroup `toml:"group-delete"`
+	DeleteUsers []*DeleteUsers `toml:"users-delete"`
 }
 
 // UpdateUsers is a type of modification that adds a group to a specific set of users
@@ -59,6 +60,11 @@ type RemoveGroup struct {
 	GroupName string `toml:"name"`
 }
 
+// DeleteUser is a type of modification that attempts to delete a preexisting user from the system
+type DeleteUsers struct {
+	UserName string `toml:"name"`
+}
+
 // LoadMigrations finds migration files in SysDir and UsrDir and attempts to load them
 func LoadMigrations() []Migration {
 	var allMigrations []Migration
@@ -139,6 +145,9 @@ func (m *Migration) Run(context *Context) {
 	for _, task := range m.RemoveGroup {
 		m.removeGroup(context, task)
 	}
+	for _, task := range m.DeleteUsers {
+		m.deleteUsers(context, task)
+	}
 }
 
 func (m *Migration) updateUsers(context *Context, task *UpdateUsers) {
@@ -225,8 +234,30 @@ func (m *Migration) removeGroup(context *Context, task *RemoveGroup) {
 		} else {
 			waterlog.Debugf("\tSuccessfully removed group %s from the system\n", task.GroupName)
 		}
-	// Group doesn't exist
 	} else if byName == nil {
 		waterlog.Debugf("\tGroup %s doesn't exist, skipping\n", task.GroupName)
 	}
 }
+
+func (m *Migration) deleteUsers(context *Context, task *DeleteUsers) {
+
+	var byName *User
+
+	for _, user := range context.users {
+		if user.Name == task.UserName {
+			user := user
+			byName = &user
+			if ran, err := context.DeleteUser(&user); err != nil {
+				waterlog.Warnf("\tFailed to delete user %s from system due to error: %s\n", task.UserName, err)
+			} else if ran {
+				waterlog.Debugf("\tSuccessfully deleted user %s from the system\n", task.UserName)
+			} else {
+				waterlog.Warnf("\tUnknown error occured when deleting user %s from system, err %s\n", task.UserName, err)
+			}
+		}
+	}
+
+	if byName == nil {
+		waterlog.Debugf("\tUser %s doesn't exist on the system, skipping\n", task.UserName)
+	}
+}