oshi.driver.linux.proc.UserGroupInfo Maven / Gradle / Ivy
/**
* MIT License
*
* Copyright (c) 2010 - 2020 The OSHI Project Contributors: https://github.com/oshi/oshi/graphs/contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package oshi.driver.linux.proc;
import static oshi.util.Memoizer.memoize;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.function.Supplier;
import oshi.annotation.concurrent.ThreadSafe;
import oshi.util.Constants;
import oshi.util.ExecutingCommand;
/**
* Utility class to temporarily cache the userID and group maps in Linux, for
* parsing process ownership. Cache expires after one minute.
*/
@ThreadSafe
public final class UserGroupInfo {
// Temporarily cache users and groups, update each minute
private static final Supplier> usersIdMap = memoize(UserGroupInfo::getUserMap,
TimeUnit.MINUTES.toNanos(1));
private static final Supplier> groupsIdMap = memoize(UserGroupInfo::getGroupMap,
TimeUnit.MINUTES.toNanos(1));
private UserGroupInfo() {
}
/**
* Gets a user from their ID
*
* @param userId
* a user ID
* @return a pair containing that user id as the first element and the user name
* as the second
*/
public static String getUser(String userId) {
return usersIdMap.get().getOrDefault(userId, Constants.UNKNOWN);
}
/**
* Gets the group name for a given ID
*
* @param groupId
* a {@link java.lang.String} object.
* @return a {@link java.lang.String} object.
*/
public static String getGroupName(String groupId) {
return groupsIdMap.get().getOrDefault(groupId, Constants.UNKNOWN);
}
private static Map getUserMap() {
HashMap userMap = new HashMap<>();
List passwd = ExecutingCommand.runNative("getent passwd");
// see man 5 passwd for the fields
for (String entry : passwd) {
String[] split = entry.split(":");
if (split.length > 2) {
String userName = split[0];
String uid = split[2];
// it is allowed to have multiple entries for the same userId,
// we use the first one
userMap.putIfAbsent(uid, userName);
}
}
return userMap;
}
private static Map getGroupMap() {
Map groupMap = new HashMap<>();
List group = ExecutingCommand.runNative("getent group");
// see man 5 group for the fields
for (String entry : group) {
String[] split = entry.split(":");
if (split.length > 2) {
String groupName = split[0];
String gid = split[2];
groupMap.putIfAbsent(gid, groupName);
}
}
return groupMap;
}
}