summaryrefslogtreecommitdiffstats
path: root/kioslave/sftp/ksshprocess.cpp
blob: 9b2323bd61a6dcda6467f40f35d14afd94543c85 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
/***************************************************************************
                          ksshprocess.cpp  -  description
                             -------------------
    begin                : Tue Jul 31 2001
    copyright            : (C) 2001 by Lucas Fisher
    email                : ljfisher@purdue.edu
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

/*
 * See the KSshProcess header for examples on use.
 *
 * This class uses a hacked version of the PTYProcess
 * class.  This was needed because the kdelibs PTYProcess does not provide 
 * access to the pty file descriptor which we need, because ssh prints the
 * password prompt to the pty and reads the password from the pty.  I don't
 * feel I know enough about ptys to confidently modify the orignial
 * PTYProcess class.
 *
 * To start ssh we take the arguments the user gave us
 * in the SshOptList and build the ssh command arguments based on the version
 * of ssh we are using.  This command and its arguments are  passed to
 * PTYProcess for execution.  Once ssh is started we scan each line of input
 * from stdin, stderr, and the pty for recognizable strings.  The recognizable
 * strings are taken from several string tables.  Each table contains a string
 * for each specific version of ssh we support and a string for a generic
 * version of OpenSSH and commercial SSH incase we don't recognized the 
 * specific ssh version strings (as when a new SSH version is released after
 * a release of KSshProcess).  There are tables for ssh version strings,
 * password prompts, new host key errors, different host key errors,
 * messages than indicate a successful connect, authentication errors, etc.
 * If we find user interaction is necessary, for instance to provide a 
 * password or passphrase, we return a err code to the user who can send
 * a message to KSshProcess, using one of several methods, to correct
 * the error.
 *
 * Determining when the ssh connection has successfully authenticationed has
 * proved to be the most difficult challenge.  OpenSSH does not print a message
 * on successful authentication, thus the only way to know is to send data
 * and wait for a return.  The problem here is sometimes it can take a bit
 * to establish the connection (for example, do to DNS lookups).  This means
 * the user may be sitting there waiting for a connection that failed.
 * Instead, ssh is always started with the verbose flag.  Then we look for
 * a message that indicates auth succeeded.  This is hazardous because
 * debug messages are more likely to change between OpenSSH releases.
 * Thus, we could become incompatible with new OpenSSH releases.
 */

#include <config.h>

#include "ksshprocess.h"

#include <stdio.h>
#include <errno.h>

#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif

#include <kstandarddirs.h>
#include <klocale.h>
#include <tqregexp.h>

/*
 * The following are tables of string and regexps we match
 * against the output of ssh.  An entry in each array 
 * corresponds the the version of ssh found in versionStrs[].
 * 
 * The version strings must be ordered in the array from most
 * specific to least specific in cases where the beginning
 * of several version strings are the similar. For example,
 * consider the openssh version strings.  The generic "OpenSSH"
 * must be the last of the openssh version strings in the array
 * so that is matched last. We use these generic version strings
 * so we can do a best effor to  support unknown ssh versions.
 */
TQRegExp KSshProcess::versionStrs[] = {
    TQRegExp("OpenSSH_3\\.[6-9]|OpenSSH_[1-9]*[4-9]\\.[0-9]"),
    TQRegExp("OpenSSH"),
    TQRegExp("SSH Secure Shell")
};

const char * const KSshProcess::passwordPrompt[] = {
    "password:", // OpenSSH
    "password:", // OpenSSH
    "password:"  // SSH
};

const char * const KSshProcess::passphrasePrompt[] = {
    "Enter passphrase for key",
    "Enter passphrase for key",
    "Passphrase for key"
};

const char * const KSshProcess::authSuccessMsg[] = {
    "Authentication succeeded",
    "ssh-userauth2 successful",
    "Received SSH_CROSS_AUTHENTICATED packet"
};

const char* const KSshProcess::authFailedMsg[] = {
    "Permission denied (",
    "Permission denied (",
    "Authentication failed."
};

const char* const KSshProcess::tryAgainMsg[] = {
    "please try again",
    "please try again",
    "adjfhjsdhfdsjfsjdfhuefeufeuefe"
};

TQRegExp KSshProcess::hostKeyMissingMsg[] = {
    TQRegExp("The authenticity of host|No (DSA|RSA) host key is known for"),
    TQRegExp("The authenticity of host|No (DSA|RSA) host key is known for"),
    TQRegExp("Host key not found from database")
};

const char* const KSshProcess::continuePrompt[] = {
    "Are you sure you want to continue connecting (yes/no)?",
    "Are you sure you want to continue connecting (yes/no)?",
    "Are you sure you want to continue connecting (yes/no)?"
};

const char* const KSshProcess::hostKeyChangedMsg[] = {
    "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!",
    "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!",
    "WARNING: HOST IDENTIFICATION HAS CHANGED!"
};

TQRegExp KSshProcess::keyFingerprintMsg[] = {
    TQRegExp("..(:..){15}"),
    TQRegExp("..(:..){15}"),
    TQRegExp(".....(-.....){10}")
};

TQRegExp KSshProcess::knownHostsFileMsg[] = {
    TQRegExp("Add correct host key in (.*) to get rid of this message."),
    TQRegExp("Add correct host key in (.*) to get rid of this message."),
    TQRegExp("Add correct host key to \"(.*)\"")
};


// This prompt only applies to commerical ssh.
const char* const KSshProcess::changeHostKeyOnDiskPrompt[] = {
    "as;jf;sajkfdslkfjas;dfjdsa;fj;dsajfdsajf",
    "as;jf;sajkfdslkfjas;dfjdsa;fj;dsajfdsajf",
    "Do you want to change the host key on disk (yes/no)?"
};

// We need this in addition the authFailedMsg because when
// OpenSSH gets a changed host key it will fail to connect
// depending on the StrictHostKeyChecking option.  Depending
// how this option is set, it will print "Permission denied"
// and quit, or print "Host key verification failed." and
// quit.  The later if StrictHostKeyChecking is "no".
// The former if StrictHostKeyChecking is
// "yes" or explicitly set to "ask".
TQRegExp KSshProcess::hostKeyVerifyFailedMsg[] = {
    TQRegExp("Host key verification failed\\."),
    TQRegExp("Host key verification failed\\."),
    TQRegExp("Disconnected; key exchange or algorithm? negotiation failed \\(Key exchange failed\\.\\)\\.")
};

const char * const KSshProcess::connectionClosedMsg[] = {
    "Connection closed by remote host",
    "Connection closed by remote host",
    "Connection closed by remote host"
};


void KSshProcess::SIGCHLD_handler(int) {
	while(waitpid(-1, NULL, WNOHANG) > 0);
}

void KSshProcess::installSignalHandlers() {
    struct sigaction act;
    memset(&act,0,sizeof(act));
    act.sa_handler = SIGCHLD_handler;
    act.sa_flags = 0
#ifdef SA_NOCLDSTOP
	    | SA_NOCLDSTOP
#endif
#ifdef SA_RESTART
	    | SA_RESTART
#endif
	    ;
    sigaction(SIGCHLD,&act,NULL);
}
					
void KSshProcess::removeSignalHandlers() {
	struct sigaction act;
	memset(&act,0,sizeof(act));
	act.sa_handler = SIG_DFL;
	sigaction(SIGCHLD,&act,NULL);
}

KSshProcess::KSshProcess() 
            : mVersion(UNKNOWN_VER), mConnected(false), 
        mRunning(false), mConnectState(0) {
    mSshPath = KStandardDirs::findExe(TQString::fromLatin1("ssh"));
    kdDebug(KSSHPROC) << "KSshProcess::KSshProcess(): ssh path [" << 
		mSshPath << "]" << endl;
        
	installSignalHandlers();
}

KSshProcess::KSshProcess(TQString pathToSsh)
            : mSshPath(pathToSsh), mVersion(UNKNOWN_VER), mConnected(false),
    mRunning(false), mConnectState(0)  {
	installSignalHandlers();
}

KSshProcess::~KSshProcess(){
    disconnect();
    removeSignalHandlers();
    while(waitpid(-1, NULL, WNOHANG) > 0);
}

bool KSshProcess::setSshPath(TQString pathToSsh) {
    mSshPath = pathToSsh;
    version();
    if( mVersion == UNKNOWN_VER )
        return false;

    return true;
}

KSshProcess::SshVersion KSshProcess::version() {
    TQString cmd;
    cmd = mSshPath+" -V 2>&1";

    // Get version string from ssh client.
    FILE *p;
    if( (p = popen(cmd.latin1(), "r")) == NULL ) {
        kdDebug(KSSHPROC) << "KSshProcess::version(): "
            "failed to start ssh: " << strerror(errno) << endl;
        return UNKNOWN_VER;
    }

    // Determine of the version from the version string. 
    size_t len;
    char buf[128];
    if( (len = fread(buf, sizeof(char), sizeof(buf)-1, p)) == 0 ) {
        kdDebug(KSSHPROC) << "KSshProcess::version(): "
            "Read of ssh version string failed " << 
             strerror(ferror(p)) << endl;
        return UNKNOWN_VER;
    }
    if( pclose(p) == -1 ) {
        kdError(KSSHPROC) << "KSshProcess::version(): pclose failed." << endl;
    }
    buf[len] = '\0';
    TQString ver;
    ver = buf;
    kdDebug(KSSHPROC) << "KSshProcess::version(): "
        "got version string [" << ver << "]" << endl;

    mVersion = UNKNOWN_VER;
    for(int i = 0; i < SSH_VER_MAX; i++) {
        if( ver.find(versionStrs[i]) != -1 ) {
             mVersion = (SshVersion)i;
             break;
        }
    }

    kdDebug(KSSHPROC) << "KSshPRocess::version(): version number = "
	    << mVersion << endl;
    
    if( mVersion == UNKNOWN_VER ) {
        kdDebug(KSSHPROC) << "KSshProcess::version(): "
            "Sorry, I don't know about this version of ssh" << endl;
        mError = ERR_UNKNOWN_VERSION;
        return UNKNOWN_VER;
    }

    return mVersion;
}
/*
TQString KSshProcess::versionStr() {
    if( mVersion == UNKNOWN_VER ) {
        version();
        if( mVersion == UNKNOWN_VER )
            return TQString::null;
    }

    return TQString::fromLatin1(versionStrs[mVersion]);
}
*/

bool KSshProcess::setOptions(const SshOptList& opts) {
    kdDebug(KSSHPROC) << "KSshProcess::setOptions()" << endl;
    mArgs.clear();
    SshOptListConstIterator it;
    TQString cmd, subsystem;
    mPassword = mUsername = mHost = TQString::null;
    TQCString tmp;
    for(it = opts.begin(); it != opts.end(); ++it) {
        //kdDebug(KSSHPROC) << "opt.opt = " << (*it).opt << endl;
        //kdDebug(KSSHPROC) << "opt.str = " << (*it).str << endl;
        //kdDebug(KSSHPROC) << "opt.num = " << (*it).num << endl;
        switch( (*it).opt ) {
        case SSH_VERBOSE:
            mArgs.append("-v");
            break;

        case SSH_SUBSYSTEM:
            subsystem = (*it).str;
            break;

        case SSH_PORT:
            mArgs.append("-p");
            tmp.setNum((*it).num);
            mArgs.append(tmp);
            mPort = (*it).num;
            break;

        case SSH_HOST:
            mHost = (*it).str;
            break;

        case SSH_USERNAME:
            mArgs.append("-l");
            mArgs.append((*it).str.latin1());
            mUsername = (*it).str;
            break;

        case SSH_PASSWD:
            mPassword = (*it).str;
            break;

        case SSH_PROTOCOL:
            if( mVersion <= OPENSSH ) {
                tmp = "Protocol=";
                tmp += TQString::number((*it).num).latin1();
                mArgs.append("-o");
                mArgs.append(tmp);
            }
            else if( mVersion <= SSH ) {
                if( (*it).num == 1 ) {
                    mArgs.append("-1");
                }
                // else uses version 2 by default
            }
            break;

        case SSH_FORWARDX11:
            tmp = "ForwardX11=";
            tmp += (*it).boolean ? "yes" : "no";
            mArgs.append("-o");
            mArgs.append(tmp);
            break;

        case SSH_FORWARDAGENT:
            tmp = "ForwardAgent=";
            tmp += (*it).boolean ? "yes" : "no";
            mArgs.append("-o");
            mArgs.append(tmp);
            break;

        case SSH_ESCAPE_CHAR:
            if( (*it).num == -1 )
                tmp = "none";
            else
                tmp = (char)((*it).num);
            mArgs.append("-e");
            mArgs.append(tmp);
            break;

        case SSH_OPTION:
            // don't allow NumberOfPasswordPrompts or StrictHostKeyChecking
            // since KSshProcess depends on specific setting of these for 
            // preforming authentication correctly.
            tmp = (*it).str.latin1();
            if( tmp.contains("NumberOfPasswordPrompts") ||
                tmp.contains("StrictHostKeyChecking") ) {
                mError = ERR_INVALID_OPT;
                return false;
            }
            else {
                mArgs.append("-o");
                mArgs.append(tmp);
            }
            break;
            
        case SSH_COMMAND:
            cmd = (*it).str;
            break;

        default:
            kdDebug(KSSHPROC) << "KSshProcess::setOptions(): "
                "unrecognized ssh opt " << (*it).opt << endl;
        }
    }

    if( !subsystem.isEmpty() && !cmd.isEmpty() ) {
        kdDebug(KSSHPROC) << "KSshProcess::setOptions(): "
            "cannot use a subsystem and command at the same time" << endl;
        mError = ERR_CMD_SUBSYS_CONFLICT;
        mErrorMsg = i18n("Cannot specify a subsystem and command at the same time.");
        return false;
    }

    // These options govern the behavior of ssh and 
    // cannot be defined by the user
    //mArgs.append("-o");
    //mArgs.append("StrictHostKeyChecking=ask");
    mArgs.append("-v"); // So we get a message that the 
                        // connection was successful
    if( mVersion <= OPENSSH ) {
        // nothing
    }
    else if( mVersion <= SSH ) {
        mArgs.append("-o"); // So we can check if the connection was successful
        mArgs.append("AuthenticationSuccessMsg=yes");
    }

    if( mHost.isEmpty() ) {
        kdDebug(KSSHPROC) << "KSshProcess::setOptions(): "
            "a host name must be supplied" << endl;
        return false;
    }
    else {
        mArgs.append(mHost.latin1());
    }

    if( !subsystem.isEmpty() ) {
        mArgs.append("-s");
        mArgs.append(subsystem.latin1());
    }

    if( !cmd.isEmpty() ) {
        mArgs.append(cmd.latin1());
    }

    return true;
}

void KSshProcess::printArgs() {
    TQValueListIterator<TQCString> it;
    for( it = mArgs.begin(); it != mArgs.end(); ++it) {
        kdDebug(KSSHPROC) << "arg: " << *it << endl;
    }
}


int KSshProcess::error(TQString& msg) {
    kdDebug(KSSHPROC) << "KSshProcess::error()" << endl;
    kdDebug() << mErrorMsg << endl;
    msg = mErrorMsg;
    return mError;
}

void KSshProcess::kill(int signal) {
    int pid = ssh.pid();
    
    kdDebug(KSSHPROC) << "KSshProcess::kill(signal:" << signal 
                      << "): ssh pid is " << pid << endl;
    kdDebug(KSSHPROC) << "KSshPRocess::kill(): we are " 
                      << (mConnected ? "" : "not ") << "connected" << endl;
    kdDebug(KSSHPROC) << "KSshProcess::kill(): we are " 
                      << (mRunning ? "" : "not ") << "running a ssh process" << endl;

    if( mRunning && pid > 1 ) {
            // Kill the child process...
            if ( ::kill(pid, signal) == 0 ) {
                // clean up if we tried to kill the process
                if( signal == SIGTERM || signal == SIGKILL ) {
                    while(waitpid(-1, NULL, WNOHANG) > 0);
                    mConnected = false;
                    mRunning = false;
                }
            }
            else
                kdDebug(KSSHPROC) << "KSshProcess::kill(): kill failed" << endl;
    }
    else
        kdDebug(KSSHPROC) << "KSshProcess::kill(): "
            "Refusing to kill ssh process" << endl;
}



/**
 * Try to open an ssh connection.
 * SSH prints certain messages to certain file descriptiors:
 *    passwordPrompt - pty
 *    passphrasePrompt - pty
 *    authSuccessMsg - stderr (OpenSSH), 
 *    authFailedMsg - stderr
 *    hostKeyMissing - stderr
 *    hostKeyChanged - stderr
 *    continuePrompt - stderr
 * 
 * We will use a select to wait for a line on each descriptor. Then get
 * each line that available and take action based on it.  The type
 * of messages we are looking for and the action we take on each
 * message are:
 *   passwordPrompt - Return false, set error to ERR_NEED_PASSWD.
 *                    On the next call to connect() we expect a password
 *                    to be available.
 *                    
 *   passpharsePrompt - Return false, set error to ERR_NEED_PASSPHRASE.
 *                      On the next call to connect() we expect a
 *                      passphrase to be available.
 *   
 *   authSuccessMsg - Return true, as we have successfully established a
 *                    ssh connection.
 *   
 *   authFailedMsg - Return false, set error to ERR_AUTH_FAILED. We
 *                   were unable to authenticate the connection given
 *                   the available authentication information.
 *   
 *   hostKeyMissing - Return false, set error to ERR_NEW_HOST_KEY. Caller
 *                    must call KSshProcess.acceptHostKey(bool) to accept
 *                    or reject the key before calling connect() again.
 *   
 *   hostKeyChanged - Return false, set error to ERR_DIFF_HOST_KEY. Caller
 *                    must call KSshProcess.acceptHostKey(bool) to accept
 *                    or reject the key before calling connect() again.
 *   
 *   continuePrompt - Send 'yes' or 'no' to accept or reject a key,
 *                    respectively.
 *
 */


void KSshProcess::acceptHostKey(bool accept) {
    kdDebug(KSSHPROC) << "KSshProcess::acceptHostKey(accept:"
        << accept << ")" << endl;
    mAcceptHostKey = accept;
}

void KSshProcess::setPassword(TQString password) {
    kdDebug(KSSHPROC) << "KSshProcess::setPassword(password:xxxxxxxx)" << endl;
    mPassword = password;
}

TQString KSshProcess::getLine() {
    static TQStringList buffer;
    TQString line = TQString::null;
    TQCString ptyLine, errLine;

    if( buffer.empty() ) {
        // PtyProcess buffers lines.  First check that there
        // isn't something on the PtyProces buffer or that there
        // is not data ready to be read from the pty or stderr.
        ptyLine = ssh.readLineFromPty(false);
        errLine = ssh.readLineFromStderr(false);

        // If PtyProcess did have something for us, get it and
        // place it in our line buffer.
        if( ! ptyLine.isEmpty() ) {
            buffer.prepend(TQString(ptyLine));
        }

        if( ! errLine.isEmpty() ) {
            buffer.prepend(TQString(errLine));
        }

        // If we still don't have anything in our buffer so there must
        // not be anything on the pty or stderr. Setup a select()
        // to wait for some data from SSH.
        if( buffer.empty() ) {
            //kdDebug(KSSHPROC) << "KSshProcess::getLine(): " <<
            //    "Line buffer empty, calling select() to wait for data." << endl;
            int errfd = ssh.stderrFd();
            int ptyfd = ssh.fd();
            fd_set rfds;
            fd_set efds;
            struct timeval tv;
            
            // find max file descriptor
            int maxfd = ptyfd > errfd ? ptyfd : errfd;          
            
            FD_ZERO(&rfds);
            FD_SET(ptyfd, &rfds);      // Add pty file descriptor
            FD_SET(errfd, &rfds);      // Add std error file descriptor
    
            FD_ZERO(&efds);
            FD_SET(ptyfd, &efds);
            FD_SET(errfd, &efds);
   
            tv.tv_sec = 60; tv.tv_usec = 0; // 60 second timeout
    
            // Wait for a message from ssh on stderr or the pty.
            int ret = -1;
            do 
              ret = ::select(maxfd+1, &rfds, NULL, &efds, &tv);
            while( ret == -1 && errno == EINTR );
    
            // Handle any errors from select
            if( ret == 0 ) {
                kdDebug(KSSHPROC) << "KSshProcess::connect(): " <<
                    "timed out waiting for a response" << endl;
                mError = ERR_TIMED_OUT;
                return TQString::null;
            }
            else if( ret == -1 ) {
                kdDebug(KSSHPROC) << "KSshProcess::connect(): "
                    << "select error: " << strerror(errno) << endl;
                mError = ERR_INTERNAL;
                return TQString::null;
            }
    
            // We are not respecting any type of order in which the
            // lines were received. Who knows whether pty or stderr
            // had data on it first.
            if( FD_ISSET(ptyfd, &rfds) ) {
                ptyLine = ssh.readLineFromPty(false);
                buffer.prepend(TQString(ptyLine));
                //kdDebug(KSSHPROC) << "KSshProcess::getLine(): "
                //    "line from pty -" << ptyLine  << endl;
            }
            
            if( FD_ISSET(errfd, &rfds) ) {
                errLine = ssh.readLineFromStderr(false);
                buffer.prepend(TQString(errLine));
                //kdDebug(KSSHPROC) << "KSshProcess::getLine(): "
                //    "line from err -" << errLine << endl;
            }

            if( FD_ISSET(ptyfd, &efds) ) {
                kdDebug(KSSHPROC) << "KSshProcess::getLine(): "
                    "Exception on pty file descriptor." << endl;
            }

            if( FD_ISSET(errfd, &efds) ) {
                kdDebug(KSSHPROC) << "KSshProcess::getLine(): "
                    "Exception on std err file descriptor." << endl;
            }
            
        }
    }
   
    // We should have something in our buffer now.
    // Return the last line.
    //it = buffer.end();
    //line = *it;
    //buffer.remove(it);

    line = buffer.last();
    buffer.pop_back();

    if( line.isNull() && buffer.count() > 0 ) {
        line = buffer.last();
        buffer.pop_back();
    }
    
//    kdDebug(KSSHPROC) << "KSshProcess::getLine(): " << 
//        buffer.count() << " lines in buffer" << endl;
    kdDebug(KSSHPROC) << "KSshProcess::getLine(): "
        "ssh: " << line << endl;
    

    return line;
}

// All the different states we could go through while trying to connect.
enum sshConnectState {
    STATE_START, STATE_TRY_PASSWD, STATE_WAIT_PROMPT, STATE_NEW_KEY_CONTINUE,
    STATE_DIFF_KEY_CONTINUE, STATE_FATAL, STATE_WAIT_CONTINUE_PROMPT,
    STATE_SEND_CONTINUE, STATE_AUTH_FAILED, STATE_NEW_KEY_WAIT_CONTINUE,
    STATE_DIFF_KEY_WAIT_CONTINUE, STATE_TRY_PASSPHRASE
};

// Print the state as a string. Good for debugging
const char* stateStr(int state) {
    switch(state) {
        case STATE_START:
            return "STATE_START";
        case STATE_TRY_PASSWD:
            return "STATE_TRY_PASSWD";
        case STATE_WAIT_PROMPT:
            return "STATE_WAIT_PROMPT";
        case STATE_NEW_KEY_CONTINUE:
            return "STATE_NEW_KEY_CONTINUE";
        case STATE_DIFF_KEY_CONTINUE:
            return "STATE_DIFF_KEY_CONTINUE";
        case STATE_FATAL:
            return "STATE_FATAL";
        case STATE_WAIT_CONTINUE_PROMPT:
            return "STATE_WAIT_CONTINUE_PROMPT";
        case STATE_SEND_CONTINUE:
            return "STATE_SEND_CONTINE";
        case STATE_AUTH_FAILED:
            return "STATE_AUTH_FAILED";
        case STATE_NEW_KEY_WAIT_CONTINUE:
            return "STATE_NEW_KEY_WAIT_CONTINUE";
        case STATE_DIFF_KEY_WAIT_CONTINUE:
            return "STATE_DIFF_KEY_WAIT_CONTINUE";
        case STATE_TRY_PASSPHRASE:
            return "STATE_TRY_PASSPHRASE";
    }
    return "UNKNOWN";
}

bool KSshProcess::connect() {
    if( mVersion == UNKNOWN_VER ) {
        // we don't know the ssh version yet, so find out
        version();
        if( mVersion == -1 ) {
            return false;
        }
    }

    // We'll put a limit on the number of state transitions
    // to ensure we don't go out of control.
    int transitionLimit = 500;

    while(--transitionLimit) {
        kdDebug(KSSHPROC) << "KSshProcess::connect(): "
            << "Connect state " << stateStr(mConnectState) << endl;
        
        TQString line;      // a line from ssh
        TQString msgBuf;    // buffer for important messages from ssh
                           // which are to be returned to the user
        
        switch(mConnectState) {
        // STATE_START:
        // Executes the ssh binary with the options provided.  If no options
        // have been specified, sets error and returns false. Continue to
        // state 1 if execution is successful, otherwise set error and 
        // return false.
        case STATE_START:
            // reset some key values to safe values
            mAcceptHostKey = false;
            mKeyFingerprint = TQString::null;
            mKnownHostsFile = TQString::null;
            
            if( mArgs.isEmpty() ) {
                kdDebug(KSSHPROC) << "KSshProcess::connect(): ssh options "
                    "need to be set first using setArgs()" << endl;
                mError = ERR_NO_OPTIONS;
                mErrorMsg = i18n("No options provided for ssh execution.");
                return false;
            }

            if( ssh.exec(mSshPath.latin1(), mArgs) ) {
                kdDebug(KSSHPROC) << 
                    "KSshProcess::connect(): ssh exec failed" << endl;
                mError = ERR_CANNOT_LAUNCH;
                mErrorMsg = i18n("Failed to execute ssh process.");
                return false;
            }
           
            kdDebug(KSSHPROC) << "KSshPRocess::connect(): ssh pid = " << ssh.pid() << endl;
	    
            // set flag to indicate what have started a ssh process
            mRunning = true;
            mConnectState = STATE_WAIT_PROMPT;
            break;
        
        // STATE_WAIT_PROMPT:
        // Get a line of input from the ssh process. Check the contents 
        // of the line to determine the next state. Ignore the line
        // if we don't recognize its contents.  If the line contains
        // the continue prompt, we have an error since we should never
        // get that line in this state.  Set ERR_INVALID_STATE error
        // and return false.
        case STATE_WAIT_PROMPT:
            line = getLine();
            if( line.isNull() ) {
                kdDebug(KSSHPROC) << "KSshProcess::connect(): "
                    "Got null line in STATE_WAIT_PROMPT." << endl;
                mError = ERR_INTERACT;
                mErrorMsg =
                    i18n("Error encountered while talking to ssh.");
                mConnectState = STATE_FATAL;
            }
            else if( line.find(TQString::fromLatin1(passwordPrompt[mVersion]), 0, false) != -1 ) {
                mConnectState = STATE_TRY_PASSWD;
            }
            else if( line.find(passphrasePrompt[mVersion]) != -1 ) {
                mConnectState = STATE_TRY_PASSPHRASE;
            }
            else if( line.find(authSuccessMsg[mVersion]) != -1 ) {
                return true;
            }
            else if( line.find(authFailedMsg[mVersion]) != -1
                    && line.find(tryAgainMsg[mVersion]) == -1 ) {
                mConnectState = STATE_AUTH_FAILED;
            }
            else if( line.find(hostKeyMissingMsg[mVersion]) != -1 ) {
                mConnectState = STATE_NEW_KEY_WAIT_CONTINUE;
            }
            else if( line.find(hostKeyChangedMsg[mVersion]) != -1 ) {
                mConnectState = STATE_DIFF_KEY_WAIT_CONTINUE;
            }
            else if( line.find(continuePrompt[mVersion]) != -1 ) {
                //mConnectState = STATE_SEND_CONTINUE;
                kdDebug(KSSHPROC) << "KSshProcess:connect(): "
                    "Got continue prompt where we shouldn't (STATE_WAIT_PROMPT)"
                    << endl;
                mError = ERR_INTERACT;
                mErrorMsg =
                    i18n("Error encountered while talking to ssh.");
            }
            else if( line.find(connectionClosedMsg[mVersion]) != -1 ) {
                mConnectState = STATE_FATAL;
                mError = ERR_CLOSED_BY_REMOTE_HOST;
                mErrorMsg = i18n("Connection closed by remote host.");
            }
            else if( line.find(changeHostKeyOnDiskPrompt[mVersion]) != -1 ) {
                // always say yes to this.  It always comes after commerical ssh
                // prints a "continue to connect prompt". We assume that if the
                // user choose to continue, then they also want to save the
                // host key to disk.
                ssh.writeLine("yes");
            }
            else {
                // ignore line
            }
            break; 

        // STATE_TRY_PASSWD:
        // If we have password send it to the ssh process, else
        // set error ERR_NEED_PASSWD and return false to the caller.
        // The caller then must then call KSshProcess::setPassword(TQString)
        // before calling KSshProcess::connect() again.
        //
        // Almost exactly liek STATE_TRY_PASSPHRASE.  Check there if you
        // make changes here.
        case STATE_TRY_PASSWD:
            // We have a password prompt waiting for us to supply
            // a password.  Send that password to ssh.  If the caller
            // did not supply a password like we asked, then ask
            // again.
            if( !mPassword.isEmpty() ) {
//                ssh.WaitSlave();
                ssh.writeLine(mPassword.latin1());
                
                // Overwrite the password so it isn't in memory.
                mPassword.fill(TQChar('X'));
                
                // Set the password to null so we will request another
                // password if this one fails.
                mPassword = TQString::null;
                
                mConnectState = STATE_WAIT_PROMPT;
            }
            else {
                kdDebug(KSSHPROC) << "KSshProcess::connect() "
                    "Need password from caller." << endl;
                // The caller needs to supply a password before
                // connecting can continue.
                mError = ERR_NEED_PASSWD;
                mErrorMsg = i18n("Please supply a password.");
                mConnectState = STATE_TRY_PASSWD;
                return false;
            }
            break;

        // STATE_TRY_KEY_PASSPHRASE:
        // If we have passphrase send it to the ssh process, else
        // set error ERR_NEED_PASSPHRASE and return false to the caller.
        // The caller then must then call KSshProcess::setPassword(TQString)
        // before calling KSshProcess::connect() again.
        //
        // Almost exactly like STATE_TRY_PASSWD. The only difference is 
        // the error we set if we don't have a passphrase.  We duplicate
        // this code to keep in the spirit of the state machine.
        case STATE_TRY_PASSPHRASE:
            // We have a passphrase prompt waiting for us to supply
            // a passphrase.  Send that passphrase to ssh.  If the caller
            // did not supply a passphrase like we asked, then ask
            // again.
            if( !mPassword.isEmpty() ) {
//                ssh.WaitSlave();
                ssh.writeLine(mPassword.latin1());
                
                // Overwrite the password so it isn't in memory.
                mPassword.fill(TQChar('X'));
                
                // Set the password to null so we will request another
                // password if this one fails.
                mPassword = TQString::null;
                
                mConnectState = STATE_WAIT_PROMPT;
            }
            else {
                kdDebug(KSSHPROC) << "KSshProcess::connect() "
                    "Need passphrase from caller." << endl;
                // The caller needs to supply a passphrase before
                // connecting can continue.
                mError = ERR_NEED_PASSPHRASE;
                mErrorMsg = i18n("Please supply the passphrase for " 
                    "your SSH private key.");
                mConnectState = STATE_TRY_PASSPHRASE;
                return false;
            }
            break;

        // STATE_AUTH_FAILED:
        // Authentication has failed.  Tell the caller by setting the
        // ERR_AUTH_FAILED error and returning false. If
        // auth has failed then ssh should have exited, but
        // we will kill it to make sure. 
        case STATE_AUTH_FAILED:
            mError = ERR_AUTH_FAILED;
            mErrorMsg = i18n("Authentication to %1 failed").arg(mHost);
            mConnectState = STATE_FATAL;
            break; 
        
        // STATE_NEW_KEY_WAIT_CONTINUE:
        // Grab lines from ssh until we get a continue prompt or a auth
        // denied.  We will get the later if StrictHostKeyChecking is set
        // to yes.  Go to STATE_NEW_KEY_CONTINUE if we get a continue prompt.
        case STATE_NEW_KEY_WAIT_CONTINUE:
            line = getLine();
            if( line.isNull() ) {
                kdDebug(KSSHPROC) << "KSshProcess::connect(): "
                    "Got null line in STATE_NEW_KEY_WAIT_CONTINUE." << endl;
                mError = ERR_INTERACT;
                mErrorMsg =
                    i18n("Error encountered while talking to ssh.");
                mConnectState = STATE_FATAL;
            }
            else if( (line.find(authFailedMsg[mVersion]) != -1
                           && line.find(tryAgainMsg[mVersion]) == -1)
                    || line.find(hostKeyVerifyFailedMsg[mVersion]) != -1 ) {
                mError = ERR_AUTH_FAILED_NEW_KEY;
                mErrorMsg = i18n(
                    "The identity of the remote host '%1' could not be verified "
                    "because the host's key is not in the \"known hosts\" file."
                ).arg(mHost);
                
                if( mKnownHostsFile.isEmpty() ) {
                    mErrorMsg += i18n(
                        " Manually, add the host's key to the \"known hosts\" "
                        "file or contact your administrator."
                    );
                }
                else {
                    mErrorMsg += i18n(
                        " Manually, add the host's key to %1 "
                        "or contact your administrator."
                    ).arg(mKnownHostsFile);
                }

                mConnectState = STATE_FATAL;
            }
            else if( line.find(continuePrompt[mVersion]) != -1 ) {
                mConnectState = STATE_NEW_KEY_CONTINUE;
            }
            else if( line.find(connectionClosedMsg[mVersion]) != -1 ) {
                mConnectState = STATE_FATAL;
                mError = ERR_CLOSED_BY_REMOTE_HOST;
                mErrorMsg = i18n("Connection closed by remote host.");
            }
            else if( line.find(keyFingerprintMsg[mVersion]) != -1 ) {
                mKeyFingerprint = keyFingerprintMsg[mVersion].cap();
                kdDebug(KSSHPROC) << "Found key fingerprint: " << mKeyFingerprint << endl;
                mConnectState = STATE_NEW_KEY_WAIT_CONTINUE;
            }
            else {
                // ignore line
            }
            break; 
            
        
        // STATE_NEW_KEY_CONTINUE:
        // We got a continue prompt for the new key message.  Set the error 
        // message to reflect this, return false and hope for caller response.
        case STATE_NEW_KEY_CONTINUE:
            mError = ERR_NEW_HOST_KEY;
            mErrorMsg = i18n(
                "The identity of the remote host '%1' could not be "
                "verified. The host's key fingerprint is:\n%2\nYou should "
                "verify the fingerprint with the host's administrator before "
                "connecting.\n\n"
                "Would you like to accept the host's key and connect anyway? "
            ).arg(mHost).arg(mKeyFingerprint);
            mConnectState = STATE_SEND_CONTINUE;
            return false;

        // STATE_DIFF_KEY_WAIT_CONTINUE:
        // Grab lines from ssh until we get a continue prompt or a auth
        // denied.  We will get the later if StrictHostKeyChecking is set
        // to yes.  Go to STATE_DIFF_KEY_CONTINUE if we get a continue prompt.
        case STATE_DIFF_KEY_WAIT_CONTINUE:
            line = getLine();
            if( line.isNull() ) {
                kdDebug(KSSHPROC) << "KSshProcess::connect(): "
                    "Got null line in STATE_DIFF_KEY_WAIT_CONTINUE." << endl;
                mError = ERR_INTERACT;
                mErrorMsg =
                    i18n("Error encountered while talking to ssh.");
                mConnectState = STATE_FATAL;
            }
            else if( (line.find(authFailedMsg[mVersion]) != -1
                           && line.find(tryAgainMsg[mVersion]) == -1)
                    || line.find(hostKeyVerifyFailedMsg[mVersion]) != -1 ) {
                mError = ERR_AUTH_FAILED_DIFF_KEY;
                mErrorMsg = i18n(
                    "WARNING: The identity of the remote host '%1' has changed!\n\n"
                    "Someone could be eavesdropping on your connection, or the "
                    "administrator may have just changed the host's key. "
                    "Either way, you should verify the host's key fingerprint with the host's "
                    "administrator. The key fingerprint is:\n%2\n"
                    "Add the correct host key to \"%3\" to "
                    "get rid of this message."
                ).arg(mHost).arg(mKeyFingerprint).arg(mKnownHostsFile);
                mConnectState = STATE_FATAL;
            }
            else if( line.find(continuePrompt[mVersion]) != -1 ) {
                mConnectState = STATE_DIFF_KEY_CONTINUE;
            }
            else if( line.find(keyFingerprintMsg[mVersion]) != -1 ) {
                mKeyFingerprint = keyFingerprintMsg[mVersion].cap();
                kdDebug(KSSHPROC) << "Found key fingerprint: " << mKeyFingerprint << endl;
                mConnectState = STATE_DIFF_KEY_WAIT_CONTINUE;
            }
            else if( line.find(knownHostsFileMsg[mVersion]) != -1 ) {
                mKnownHostsFile = (knownHostsFileMsg[mVersion]).cap(1);
                kdDebug(KSSHPROC) << "Found known hosts file name: " << mKnownHostsFile << endl;
                mConnectState = STATE_DIFF_KEY_WAIT_CONTINUE;
            }
            else {
                // ignore line
            }
            break; 
            
        // STATE_DIFF_KEY_CONTINUE:
        // We got a continue prompt for the different key message. 
        // Set ERR_DIFF_HOST_KEY error
        // and return false to signal need to caller action.
        case STATE_DIFF_KEY_CONTINUE:
            mError = ERR_DIFF_HOST_KEY;
            mErrorMsg = i18n(
                "WARNING: The identity of the remote host '%1' has changed!\n\n"
                "Someone could be eavesdropping on your connection, or the "
                "administrator may have just changed the host's key. "
                "Either way, you should verify the host's key fingerprint with the host's "
                "administrator before connecting. The key fingerprint is:\n%2\n\n"
                "Would you like to accept the host's new key and connect anyway?"
            ).arg(mHost).arg(mKeyFingerprint);
            mConnectState = STATE_SEND_CONTINUE;
            return false;

        // STATE_SEND_CONTINUE:
        // We found a continue prompt.  Send our answer.
        case STATE_SEND_CONTINUE:
            if( mAcceptHostKey ) {
                kdDebug(KSSHPROC) << "KSshProcess::connect(): "
                    "host key accepted" << endl;
                ssh.writeLine("yes");
                mConnectState = STATE_WAIT_PROMPT;
            }
            else {
                kdDebug(KSSHPROC) << "KSshProcess::connect(): "
                    "host key rejected" << endl;
                ssh.writeLine("no");
                mError = ERR_HOST_KEY_REJECTED;
                mErrorMsg = i18n("Host key was rejected.");
                mConnectState = STATE_FATAL;
            }
            break;

        // STATE_FATAL:
        // Something bad happened that we cannot recover from.
        // Kill the ssh process and set flags to show we have
        // ended the connection and killed ssh.
        // 
        // mError and mErrorMsg should be set by the immediately
        // previous state.
        case STATE_FATAL:
            kill();
            mConnected = false;
            mRunning = false;
            mConnectState = STATE_START;
            // mError, mErroMsg set by last state
            return false;
        
        default:
            kdDebug(KSSHPROC) << "KSshProcess::connect(): "
                "Invalid state number - " << mConnectState << endl;
            mError = ERR_INVALID_STATE;
            mConnectState = STATE_FATAL;
        }
    }

    // we should never get here
    kdDebug(KSSHPROC) << "KSshProcess::connect(): " <<
        "After switch(). We shouldn't be here." << endl;
    mError = ERR_INTERNAL;
    return false;
}
            
void KSshProcess::disconnect() {
    kill();
    mConnected = false;
    mRunning = false;
    mConnectState = STATE_START;
}