Liferay-Blog

In order to place your custom portlet to the control panel just add the following lines to your liferay-portlet.xml:

Liferay-Blog
/icon.png
apps
100
de.blogspot.blog.liferay.ControlPanelEntryHandler
...

Here are the explanations taken from liferay-portlet-app_6_2_0.dtd:

control-panel-entry-category: Set the control-panel-entry-category value to "my" to make this portlet available within the My Account administration of the user. Set the value to "apps", "configuration", "sites", or "users" to make it available in the Control Panel under that category. Set the value to "site_administration.configuration", "site_administration.content", "site_administration.pages" or "site_administration.users" to make it available in the Site Administration under that category. Legacy values from previous versions of Liferay will be automatically mapped to the new values: "content" to "site_administration.content", "portal" to "users", and "server" to "apps". [Source]

control-panel-entry-weight: Set the control-panel-entry-weight value to a double number to control the position of the entry within its Control Panel category. Higher values mean that the entry will appear lower in the Control Panel menu. [Source]

control-panel-entry-class: The control-panel-entry-class value must be a class that implements com.liferay.portlet.ControlPanelEntry and is called by the Control Panel to decide whether the portlet should be shown to a specific user in a specific context. [Source]

In your control-panel-entry-class you might for example check whether the user has a certain regular role or not. Here is a example where I check if the user has a regular role called "Liferay-Blog":

package de.blogspot.blog.liferay;

import com.liferay.portal.model.Group;
import com.liferay.portal.model.Portlet;
import com.liferay.portal.model.Role;
import com.liferay.portal.model.User;
import com.liferay.portal.security.permission.PermissionChecker;
import com.liferay.portal.service.RoleLocalServiceUtil;
import com.liferay.portal.util.PortalUtil;
import com.liferay.portlet.BaseControlPanelEntry;

public class ControlPanelEntryHandler extends BaseControlPanelEntry{
 @Override
 public boolean hasAccessPermission(PermissionChecker permissionChecker, Group group, Portlet portlet) throws Exception {
 User user = permissionChecker.getUser();
 Role liferayBlogRole = RoleLocalServiceUtil.getRole(PortalUtil.getDefaultCompanyId(), "Liferay-Blog");
 
 boolean hasAccessPermission = RoleLocalServiceUtil.hasUserRole(user.getUserId(), liferayBlogRole.getRoleId());
 
 return hasAccessPermission;
 }
}