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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * particular file as subject to the "Classpath" exception as provided
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package com.sun.security.auth.module;

import java.util.*;
import java.io.IOException;
import javax.security.auth.*;
import javax.security.auth.callback.*;
import javax.security.auth.login.*;
import javax.security.auth.spi.*;
import com.sun.security.auth.UnixPrincipal;
import com.sun.security.auth.UnixNumericUserPrincipal;
import com.sun.security.auth.UnixNumericGroupPrincipal;

This LoginModule imports a user's Unix Principal information (UnixPrincipal, UnixNumericUserPrincipal, and UnixNumericGroupPrincipal) and associates them with the current Subject. 
 This LoginModule recognizes the debug option.
If set to true in the login Configuration,
debug messages will be output to the output stream, System.out.
/**
 * This {@code LoginModule} imports a user's Unix
 * {@code Principal} information ({@code UnixPrincipal},
 * {@code UnixNumericUserPrincipal},
 * and {@code UnixNumericGroupPrincipal})
 * and associates them with the current {@code Subject}.
 *
 * <p> This LoginModule recognizes the debug option.
 * If set to true in the login Configuration,
 * debug messages will be output to the output stream, System.out.
 *
 */
public class UnixLoginModule implements LoginModule {

    // initial state
    private Subject subject;
    private CallbackHandler callbackHandler;
    private Map<String, ?> sharedState;
    private Map<String, ?> options;

    // configurable option
    private boolean debug = true;

    // UnixSystem to retrieve underlying system info
    private UnixSystem ss;

    // the authentication status
    private boolean succeeded = false;
    private boolean commitSucceeded = false;

    // Underlying system info
    private UnixPrincipal userPrincipal;
    private UnixNumericUserPrincipal UIDPrincipal;
    private UnixNumericGroupPrincipal GIDPrincipal;
    private LinkedList<UnixNumericGroupPrincipal> supplementaryGroups =
                new LinkedList<>();

    
Initialize this LoginModule. 
Params:
subject – the Subject to be authenticated.
callbackHandler – a CallbackHandler for communicating with the end user (prompting for usernames and passwords, for example).
sharedState – shared LoginModule state.
options – options specified in the login Configuration for this particular LoginModule./**
     * Initialize this {@code LoginModule}.
     *
     * @param subject the {@code Subject} to be authenticated.
     *
     * @param callbackHandler a {@code CallbackHandler} for communicating
     *                  with the end user (prompting for usernames and
     *                  passwords, for example).
     *
     * @param sharedState shared {@code LoginModule} state.
     *
     * @param options options specified in the login
     *                  {@code Configuration} for this particular
     *                  {@code LoginModule}.
     */
    public void initialize(Subject subject, CallbackHandler callbackHandler,
                           Map<String,?> sharedState,
                           Map<String,?> options) {

        this.subject = subject;
        this.callbackHandler = callbackHandler;
        this.sharedState = sharedState;
        this.options = options;

        // initialize any configured options
        debug = "true".equalsIgnoreCase((String)options.get("debug"));
    }

    
Authenticate the user (first phase).
 The implementation of this method attempts to retrieve the user's Unix Subject information by making a native Unix system call. 
Throws:
FailedLoginException – if attempts to retrieve the underlying
         system information fail.
Returns:
true in all cases (this LoginModule should not be ignored)./**
     * Authenticate the user (first phase).
     *
     * <p> The implementation of this method attempts to retrieve the user's
     * Unix {@code Subject} information by making a native Unix
     * system call.
     *
     * @exception FailedLoginException if attempts to retrieve the underlying
     *          system information fail.
     *
     * @return true in all cases (this {@code LoginModule}
     *          should not be ignored).
     */
    public boolean login() throws LoginException {

        long[] unixGroups = null;

        try {
            ss = new UnixSystem();
        } catch (UnsatisfiedLinkError ule) {
            succeeded = false;
            throw new FailedLoginException
                                ("Failed in attempt to import " +
                                "the underlying system identity information" +
                                " on " + System.getProperty("os.name"));
        }
        userPrincipal = new UnixPrincipal(ss.getUsername());
        UIDPrincipal = new UnixNumericUserPrincipal(ss.getUid());
        GIDPrincipal = new UnixNumericGroupPrincipal(ss.getGid(), true);
        if (ss.getGroups() != null && ss.getGroups().length > 0) {
            unixGroups = ss.getGroups();
            for (int i = 0; i < unixGroups.length; i++) {
                UnixNumericGroupPrincipal ngp =
                    new UnixNumericGroupPrincipal
                    (unixGroups[i], false);
                if (!ngp.getName().equals(GIDPrincipal.getName()))
                    supplementaryGroups.add(ngp);
            }
        }
        if (debug) {
            System.out.println("\t\t[UnixLoginModule]: " +
                    "succeeded importing info: ");
            System.out.println("\t\t\tuid = " + ss.getUid());
            System.out.println("\t\t\tgid = " + ss.getGid());
            unixGroups = ss.getGroups();
            for (int i = 0; i < unixGroups.length; i++) {
                System.out.println("\t\t\tsupp gid = " + unixGroups[i]);
            }
        }
        succeeded = true;
        return true;
    }

    
Commit the authentication (second phase).
 This method is called if the LoginContext's
overall authentication succeeded
(the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL LoginModules
succeeded).
 If this LoginModule's own authentication attempt succeeded (the importing of the Unix authentication information succeeded), then this method associates the Unix Principals with the Subject currently tied to the LoginModule. If this LoginModule's authentication attempted failed, then this method removes any state that was originally saved. 
Throws:
LoginException – if the commit fails
Returns:
true if this LoginModule's own login and commit attempts
         succeeded, or false otherwise./**
     * Commit the authentication (second phase).
     *
     * <p> This method is called if the LoginContext's
     * overall authentication succeeded
     * (the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL LoginModules
     * succeeded).
     *
     * <p> If this LoginModule's own authentication attempt
     * succeeded (the importing of the Unix authentication information
     * succeeded), then this method associates the Unix Principals
     * with the {@code Subject} currently tied to the
     * {@code LoginModule}.  If this LoginModule's
     * authentication attempted failed, then this method removes
     * any state that was originally saved.
     *
     * @exception LoginException if the commit fails
     *
     * @return true if this LoginModule's own login and commit attempts
     *          succeeded, or false otherwise.
     */
    public boolean commit() throws LoginException {
        if (succeeded == false) {
            if (debug) {
                System.out.println("\t\t[UnixLoginModule]: " +
                    "did not add any Principals to Subject " +
                    "because own authentication failed.");
            }
            return false;
        } else {
            if (subject.isReadOnly()) {
                throw new LoginException
                    ("commit Failed: Subject is Readonly");
            }
            if (!subject.getPrincipals().contains(userPrincipal))
                subject.getPrincipals().add(userPrincipal);
            if (!subject.getPrincipals().contains(UIDPrincipal))
                subject.getPrincipals().add(UIDPrincipal);
            if (!subject.getPrincipals().contains(GIDPrincipal))
                subject.getPrincipals().add(GIDPrincipal);
            for (int i = 0; i < supplementaryGroups.size(); i++) {
                if (!subject.getPrincipals().contains
                    (supplementaryGroups.get(i)))
                    subject.getPrincipals().add(supplementaryGroups.get(i));
            }

            if (debug) {
                System.out.println("\t\t[UnixLoginModule]: " +
                    "added UnixPrincipal,");
                System.out.println("\t\t\t\tUnixNumericUserPrincipal,");
                System.out.println("\t\t\t\tUnixNumericGroupPrincipal(s),");
                System.out.println("\t\t\t to Subject");
            }

            commitSucceeded = true;
            return true;
        }
    }

    
Abort the authentication (second phase).
 This method is called if the LoginContext's
overall authentication failed.
(the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL LoginModules
did not succeed).
 This method cleans up any state that was originally saved as part of the authentication attempt from the login and commit methods. 
Throws:
LoginException – if the abort fails
Returns:
false if this LoginModule's own login and/or commit attempts
         failed, and true otherwise./**
     * Abort the authentication (second phase).
     *
     * <p> This method is called if the LoginContext's
     * overall authentication failed.
     * (the relevant REQUIRED, REQUISITE, SUFFICIENT and OPTIONAL LoginModules
     * did not succeed).
     *
     * <p> This method cleans up any state that was originally saved
     * as part of the authentication attempt from the {@code login}
     * and {@code commit} methods.
     *
     * @exception LoginException if the abort fails
     *
     * @return false if this LoginModule's own login and/or commit attempts
     *          failed, and true otherwise.
     */
    public boolean abort() throws LoginException {
        if (debug) {
            System.out.println("\t\t[UnixLoginModule]: " +
                "aborted authentication attempt");
        }

        if (succeeded == false) {
            return false;
        } else if (succeeded == true && commitSucceeded == false) {

            // Clean out state
            succeeded = false;
            ss = null;
            userPrincipal = null;
            UIDPrincipal = null;
            GIDPrincipal = null;
            supplementaryGroups = new LinkedList<UnixNumericGroupPrincipal>();
        } else {
            // overall authentication succeeded and commit succeeded,
            // but someone else's commit failed
            logout();
        }
        return true;
    }

    
Logout the user
 This method removes the Principals associated with the Subject. 
Throws:
LoginException – if the logout fails
Returns:
true in all cases (this LoginModule should not be ignored)./**
     * Logout the user
     *
     * <p> This method removes the Principals associated
     * with the {@code Subject}.
     *
     * @exception LoginException if the logout fails
     *
     * @return true in all cases (this {@code LoginModule}
     *          should not be ignored).
     */
    public boolean logout() throws LoginException {

        if (subject.isReadOnly()) {
                throw new LoginException
                    ("logout Failed: Subject is Readonly");
            }
        // remove the added Principals from the Subject
        subject.getPrincipals().remove(userPrincipal);
        subject.getPrincipals().remove(UIDPrincipal);
        subject.getPrincipals().remove(GIDPrincipal);
        for (int i = 0; i < supplementaryGroups.size(); i++) {
            subject.getPrincipals().remove(supplementaryGroups.get(i));
        }

        // clean out state
        ss = null;
        succeeded = false;
        commitSucceeded = false;
        userPrincipal = null;
        UIDPrincipal = null;
        GIDPrincipal = null;
        supplementaryGroups = new LinkedList<UnixNumericGroupPrincipal>();

        if (debug) {
            System.out.println("\t\t[UnixLoginModule]: " +
                "logged out Subject");
        }
        return true;
    }
}