aboutsummaryrefslogtreecommitdiff
path: root/tests/server/tftpd.c
blob: 97669896c50d99731829a4a5ef286490079aeb13 (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
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * $Id$
 *
 * Trivial file transfer protocol server.
 *
 * This code includes many modifications by Jim Guyton <guyton@rand-unix>
 *
 * This source file was started based on netkit-tftpd 0.17
 * Heavily modified for curl's test suite
 */

/*
 * Copyright (c) 1983 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#define CURL_NO_OLDIES

#include "setup.h" /* portability help from the lib directory */

#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifdef HAVE_SIGNAL_H
#include <signal.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_ARPA_TFTP_H
#include <arpa/tftp.h>
#else
#include "tftp.h"
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_SYS_FILIO_H
/* FIONREAD on Solaris 7 */
#include <sys/filio.h>
#endif

#include <setjmp.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_PWD_H
#include <pwd.h>
#endif

#define ENABLE_CURLX_PRINTF
/* make the curlx header define all printf() functions to use the curlx_*
   versions instead */
#include "curlx.h" /* from the private lib dir */
#include "getpart.h"
#include "util.h"
#include "warnless.h"

/* include memdebug.h last */
#include "memdebug.h"

/*****************************************************************************
*                      STRUCT DECLARATIONS AND DEFINES                       *
*****************************************************************************/

#ifndef PKTSIZE
#define PKTSIZE (SEGSIZE + 4)  /* SEGSIZE defined in arpa/tftp.h */
#endif

struct testcase {
  char *buffer;   /* holds the file data to send to the client */
  size_t bufsize; /* size of the data in buffer */
  char *rptr;     /* read pointer into the buffer */
  size_t rcount;  /* amount of data left to read of the file */
  long num;       /* test case number */
  int ofile;      /* file descriptor for output file when uploading to us */
};

struct formats {
  const char *f_mode;
  int f_convert;
};

struct errmsg {
  int e_code;
  const char *e_msg;
};

/*
 * bf.counter values in range [-1 .. SEGSIZE] represents size of data in the
 * bf.buf buffer. Additionally it can also hold flags BF_ALLOC or BF_FREE.
 */

struct bf {
  int counter;            /* size of data in buffer, or flag */
  char buf[PKTSIZE];      /* room for data packet */
};

#define BF_ALLOC -3       /* alloc'd but not yet filled */
#define BF_FREE  -2       /* free */

#define opcode_RRQ   1
#define opcode_WRQ   2
#define opcode_DATA  3
#define opcode_ACK   4
#define opcode_ERROR 5

#define TIMEOUT      5

#undef MIN
#define MIN(x,y) ((x)<(y)?(x):(y))

#ifndef DEFAULT_LOGFILE
#define DEFAULT_LOGFILE "log/tftpd.log"
#endif

#define REQUEST_DUMP  "log/server.input"

#define DEFAULT_PORT 8999 /* UDP */

/*****************************************************************************
*                              GLOBAL VARIABLES                              *
*****************************************************************************/

static struct errmsg errmsgs[] = {
  { EUNDEF,       "Undefined error code" },
  { ENOTFOUND,    "File not found" },
  { EACCESS,      "Access violation" },
  { ENOSPACE,     "Disk full or allocation exceeded" },
  { EBADOP,       "Illegal TFTP operation" },
  { EBADID,       "Unknown transfer ID" },
  { EEXISTS,      "File already exists" },
  { ENOUSER,      "No such user" },
  { -1,           0 }
};

static struct formats formata[] = {
  { "netascii",   1 },
  { "octet",      0 },
  { NULL,         0 }
};

static struct bf bfs[2];

static int nextone;     /* index of next buffer to use */
static int current;     /* index of buffer in use */

                           /* control flags for crlf conversions */
static int newline = 0;    /* fillbuf: in middle of newline expansion */
static int prevchar = -1;  /* putbuf: previous char (cr check) */

static char buf[PKTSIZE];
static char ackbuf[PKTSIZE];

static struct sockaddr_in from;
static curl_socklen_t fromlen;

static curl_socket_t peer = CURL_SOCKET_BAD;

static int timeout;
static int maxtimeout = 5 * TIMEOUT;

static unsigned short sendblock; /* block count used by sendtftp() */
static struct tftphdr *sdp;      /* data buffer used by sendtftp() */
static struct tftphdr *sap;      /* ack buffer  used by sendtftp() */

static unsigned short recvblock; /* block count used by recvtftp() */
static struct tftphdr *rdp;      /* data buffer used by recvtftp() */
static struct tftphdr *rap;      /* ack buffer  used by recvtftp() */

#ifdef ENABLE_IPV6
static bool use_ipv6 = FALSE;
#endif
static const char *ipv_inuse = "IPv4";

const  char *serverlogfile = DEFAULT_LOGFILE;
static char *pidname= (char *)".tftpd.pid";
static int serverlogslocked = 0;
static int wrotepidfile = 0;

#ifdef HAVE_SIGSETJMP
static sigjmp_buf timeoutbuf;
#endif

#if defined(HAVE_ALARM) && defined(SIGALRM)
static int rexmtval = TIMEOUT;
#endif

/* do-nothing macro replacement for systems which lack siginterrupt() */

#ifndef HAVE_SIGINTERRUPT
#define siginterrupt(x,y) do {} while(0)
#endif

/* vars used to keep around previous signal handlers */

typedef RETSIGTYPE (*SIGHANDLER_T)(int);

#ifdef SIGHUP
static SIGHANDLER_T old_sighup_handler  = SIG_ERR;
#endif

#ifdef SIGPIPE
static SIGHANDLER_T old_sigpipe_handler = SIG_ERR;
#endif

#ifdef SIGINT
static SIGHANDLER_T old_sigint_handler  = SIG_ERR;
#endif

#ifdef SIGTERM
static SIGHANDLER_T old_sigterm_handler = SIG_ERR;
#endif

/* var which if set indicates that the program should finish execution */

SIG_ATOMIC_T got_exit_signal = 0;

/* if next is set indicates the first signal handled in exit_signal_handler */

static volatile int exit_signal = 0;

/*****************************************************************************
*                            FUNCTION PROTOTYPES                             *
*****************************************************************************/

static struct tftphdr *rw_init(int);

static struct tftphdr *w_init(void);

static struct tftphdr *r_init(void);

static int readit(struct testcase *test,
                  struct tftphdr **dpp,
                  int convert);

static int writeit(struct testcase *test,
                   struct tftphdr **dpp,
                   int ct,
                   int convert);

static void read_ahead(struct testcase *test, int convert);

static ssize_t write_behind(struct testcase *test, int convert);

static int synchnet(curl_socket_t);

static int do_tftp(struct testcase *test, struct tftphdr *tp, ssize_t size);

static int validate_access(struct testcase *test, const char *fname, int mode);

static void sendtftp(struct testcase *test, struct formats *pf);

static void recvtftp(struct testcase *test, struct formats *pf);

static void nak(int error);

#if defined(HAVE_ALARM) && defined(SIGALRM)

static void mysignal(int sig, void (*handler)(int));

static void timer(int signum);

static void justtimeout(int signum);

#endif /* HAVE_ALARM && SIGALRM */

static RETSIGTYPE exit_signal_handler(int signum);

static void install_signal_handlers(void);

static void restore_signal_handlers(void);

/*****************************************************************************
*                          FUNCTION IMPLEMENTATIONS                          *
*****************************************************************************/

#if defined(HAVE_ALARM) && defined(SIGALRM)

/*
 * Like signal(), but with well-defined semantics.
 */
static void mysignal(int sig, void (*handler)(int))
{
  struct sigaction sa;
  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = handler;
  sigaction(sig, &sa, NULL);
}

static void timer(int signum)
{
  (void)signum;

  logmsg("alarm!");

  timeout += rexmtval;
  if(timeout >= maxtimeout) {
    if(wrotepidfile) {
      wrotepidfile = 0;
      unlink(pidname);
    }
    if(serverlogslocked) {
      serverlogslocked = 0;
      clear_advisor_read_lock(SERVERLOGS_LOCK);
    }
    exit(1);
  }
#ifdef HAVE_SIGSETJMP
  siglongjmp(timeoutbuf, 1);
#endif
}

static void justtimeout(int signum)
{
  (void)signum;
}

#endif /* HAVE_ALARM && SIGALRM */

/* signal handler that will be triggered to indicate that the program
  should finish its execution in a controlled manner as soon as possible.
  The first time this is called it will set got_exit_signal to one and
  store in exit_signal the signal that triggered its execution. */

static RETSIGTYPE exit_signal_handler(int signum)
{
  int old_errno = ERRNO;
  if(got_exit_signal == 0) {
    got_exit_signal = 1;
    exit_signal = signum;
  }
  (void)signal(signum, exit_signal_handler);
  SET_ERRNO(old_errno);
}

static void install_signal_handlers(void)
{
#ifdef SIGHUP
  /* ignore SIGHUP signal */
  if((old_sighup_handler = signal(SIGHUP, SIG_IGN)) == SIG_ERR)
    logmsg("cannot install SIGHUP handler: %s", strerror(ERRNO));
#endif
#ifdef SIGPIPE
  /* ignore SIGPIPE signal */
  if((old_sigpipe_handler = signal(SIGPIPE, SIG_IGN)) == SIG_ERR)
    logmsg("cannot install SIGPIPE handler: %s", strerror(ERRNO));
#endif
#ifdef SIGINT
  /* handle SIGINT signal with our exit_signal_handler */
  if((old_sigint_handler = signal(SIGINT, exit_signal_handler)) == SIG_ERR)
    logmsg("cannot install SIGINT handler: %s", strerror(ERRNO));
  else
    siginterrupt(SIGINT, 1);
#endif
#ifdef SIGTERM
  /* handle SIGTERM signal with our exit_signal_handler */
  if((old_sigterm_handler = signal(SIGTERM, exit_signal_handler)) == SIG_ERR)
    logmsg("cannot install SIGTERM handler: %s", strerror(ERRNO));
  else
    siginterrupt(SIGTERM, 1);
#endif
}

static void restore_signal_handlers(void)
{
#ifdef SIGHUP
  if(SIG_ERR != old_sighup_handler)
    (void)signal(SIGHUP, old_sighup_handler);
#endif
#ifdef SIGPIPE
  if(SIG_ERR != old_sigpipe_handler)
    (void)signal(SIGPIPE, old_sigpipe_handler);
#endif
#ifdef SIGINT
  if(SIG_ERR != old_sigint_handler)
    (void)signal(SIGINT, old_sigint_handler);
#endif
#ifdef SIGTERM
  if(SIG_ERR != old_sigterm_handler)
    (void)signal(SIGTERM, old_sigterm_handler);
#endif
}

/*
 * init for either read-ahead or write-behind.
 * zero for write-behind, one for read-head.
 */
static struct tftphdr *rw_init(int x)
{
  newline = 0;                    /* init crlf flag */
  prevchar = -1;
  bfs[0].counter =  BF_ALLOC;     /* pass out the first buffer */
  current = 0;
  bfs[1].counter = BF_FREE;
  nextone = x;                    /* ahead or behind? */
  return (struct tftphdr *)bfs[0].buf;
}

static struct tftphdr *w_init(void)
{
  return rw_init(0); /* write-behind */
}

static struct tftphdr *r_init(void)
{
  return rw_init(1); /* read-ahead */
}

/* Have emptied current buffer by sending to net and getting ack.
   Free it and return next buffer filled with data.
 */
static int readit(struct testcase *test, struct tftphdr **dpp,
                  int convert /* if true, convert to ascii */)
{
  struct bf *b;

  bfs[current].counter = BF_FREE; /* free old one */
  current = !current;             /* "incr" current */

  b = &bfs[current];              /* look at new buffer */
  if (b->counter == BF_FREE)      /* if it's empty */
    read_ahead(test, convert);    /* fill it */

  *dpp = (struct tftphdr *)b->buf;        /* set caller's ptr */
  return b->counter;
}

/*
 * fill the input buffer, doing ascii conversions if requested
 * conversions are  lf -> cr,lf  and cr -> cr, nul
 */
static void read_ahead(struct testcase *test,
                       int convert /* if true, convert to ascii */)
{
  int i;
  char *p;
  int c;
  struct bf *b;
  struct tftphdr *dp;

  b = &bfs[nextone];              /* look at "next" buffer */
  if (b->counter != BF_FREE)      /* nop if not free */
    return;
  nextone = !nextone;             /* "incr" next buffer ptr */

  dp = (struct tftphdr *)b->buf;

  if (convert == 0) {
    /* The former file reading code did this:
       b->counter = read(fileno(file), dp->th_data, SEGSIZE); */
    size_t copy_n = MIN(SEGSIZE, test->rcount);
    memcpy(dp->th_data, test->rptr, copy_n);

    /* decrease amount, advance pointer */
    test->rcount -= copy_n;
    test->rptr += copy_n;
    b->counter = (int)copy_n;
    return;
  }

  p = dp->th_data;
  for (i = 0 ; i < SEGSIZE; i++) {
    if (newline) {
      if (prevchar == '\n')
        c = '\n';       /* lf to cr,lf */
      else
        c = '\0';       /* cr to cr,nul */
      newline = 0;
    }
    else {
      if(test->rcount) {
        c=test->rptr[0];
        test->rptr++;
        test->rcount--;
      }
      else
        break;
      if (c == '\n' || c == '\r') {
        prevchar = c;
        c = '\r';
        newline = 1;
      }
    }
    *p++ = (char)c;
  }
  b->counter = (int)(p - dp->th_data);
}

/* Update count associated with the buffer, get new buffer from the queue.
   Calls write_behind only if next buffer not available.
 */
static int writeit(struct testcase *test, struct tftphdr **dpp,
                   int ct, int convert)
{
  bfs[current].counter = ct;      /* set size of data to write */
  current = !current;             /* switch to other buffer */
  if (bfs[current].counter != BF_FREE)     /* if not free */
    write_behind(test, convert);     /* flush it */
  bfs[current].counter = BF_ALLOC;        /* mark as alloc'd */
  *dpp =  (struct tftphdr *)bfs[current].buf;
  return ct;                      /* this is a lie of course */
}

/*
 * Output a buffer to a file, converting from netascii if requested.
 * CR,NUL -> CR  and CR,LF => LF.
 * Note spec is undefined if we get CR as last byte of file or a
 * CR followed by anything else.  In this case we leave it alone.
 */
static ssize_t write_behind(struct testcase *test, int convert)
{
  char *writebuf;
  int count;
  int ct;
  char *p;
  int c;                          /* current character */
  struct bf *b;
  struct tftphdr *dp;

  b = &bfs[nextone];
  if (b->counter < -1)            /* anything to flush? */
    return 0;                     /* just nop if nothing to do */

  if(!test->ofile) {
    char outfile[256];
    snprintf(outfile, sizeof(outfile), "log/upload.%ld", test->num);
    test->ofile=open(outfile, O_CREAT|O_RDWR, 0777);
    if(test->ofile == -1) {
      logmsg("Couldn't create and/or open file %s for upload!", outfile);
      return -1; /* failure! */
    }
  }

  count = b->counter;             /* remember byte count */
  b->counter = BF_FREE;           /* reset flag */
  dp = (struct tftphdr *)b->buf;
  nextone = !nextone;             /* incr for next time */
  writebuf = dp->th_data;

  if (count <= 0)
    return -1;                    /* nak logic? */

  if (convert == 0)
    return write(test->ofile, writebuf, count);

  p = writebuf;
  ct = count;
  while (ct--) {                  /* loop over the buffer */
    c = *p++;                     /* pick up a character */
    if (prevchar == '\r') {       /* if prev char was cr */
      if (c == '\n')              /* if have cr,lf then just */
        lseek(test->ofile, -1, SEEK_CUR); /* smash lf on top of the cr */
      else
        if (c == '\0')            /* if have cr,nul then */
          goto skipit;            /* just skip over the putc */
      /* else just fall through and allow it */
    }
    /* formerly
       putc(c, file); */
    write(test->ofile, &c, 1);
    skipit:
    prevchar = c;
  }
  return count;
}

/* When an error has occurred, it is possible that the two sides are out of
 * synch.  Ie: that what I think is the other side's response to packet N is
 * really their response to packet N-1.
 *
 * So, to try to prevent that, we flush all the input queued up for us on the
 * network connection on our host.
 *
 * We return the number of packets we flushed (mostly for reporting when trace
 * is active).
 */

static int synchnet(curl_socket_t f /* socket to flush */)
{

#if defined(HAVE_IOCTLSOCKET)
  unsigned long i;
#else
  int i;
#endif
  int j = 0;
  char rbuf[PKTSIZE];
  struct sockaddr_in fromaddr;
  curl_socklen_t fromaddrlen;

  for (;;) {
#if defined(HAVE_IOCTLSOCKET)
    (void) ioctlsocket(f, FIONREAD, &i);
#else
    (void) ioctl(f, FIONREAD, &i);
#endif
    if (i) {
      j++;
      fromaddrlen = sizeof(fromaddr);
      (void)recvfrom(f, rbuf, sizeof(rbuf), 0,
                     (struct sockaddr *)&fromaddr, &fromaddrlen);
    }
    else
      break;
  }
  return j;
}

int main(int argc, char **argv)
{
  struct sockaddr_in me;
#ifdef ENABLE_IPV6
  struct sockaddr_in6 me6;
#endif /* ENABLE_IPV6 */

  struct tftphdr *tp;
  ssize_t n = 0;
  int arg = 1;
  unsigned short port = DEFAULT_PORT;
  curl_socket_t sock = CURL_SOCKET_BAD;
  int flag;
  int rc;
  int error;
  long pid;
  struct testcase test;
  int result = 0;

  memset(&test, 0, sizeof(test));

  while(argc>arg) {
    if(!strcmp("--version", argv[arg])) {
      printf("tftpd IPv4%s\n",
#ifdef ENABLE_IPV6
             "/IPv6"
#else
             ""
#endif
             );
      return 0;
    }
    else if(!strcmp("--pidfile", argv[arg])) {
      arg++;
      if(argc>arg)
        pidname = argv[arg++];
    }
    else if(!strcmp("--logfile", argv[arg])) {
      arg++;
      if(argc>arg)
        serverlogfile = argv[arg++];
    }
    else if(!strcmp("--ipv4", argv[arg])) {
#ifdef ENABLE_IPV6
      ipv_inuse = "IPv4";
      use_ipv6 = FALSE;
#endif
      arg++;
    }
    else if(!strcmp("--ipv6", argv[arg])) {
#ifdef ENABLE_IPV6
      ipv_inuse = "IPv6";
      use_ipv6 = TRUE;
#endif
      arg++;
    }
    else if(!strcmp("--port", argv[arg])) {
      arg++;
      if(argc>arg) {
        char *endptr;
        unsigned long ulnum = strtoul(argv[arg], &endptr, 10);
        if((endptr != argv[arg] + strlen(argv[arg])) ||
           (ulnum < 1025UL) || (ulnum > 65535UL)) {
          fprintf(stderr, "tftpd: invalid --port argument (%s)\n",
                  argv[arg]);
          return 0;
        }
        port = Curl_ultous(ulnum);
        arg++;
      }
    }
    else if(!strcmp("--srcdir", argv[arg])) {
      arg++;
      if(argc>arg) {
        path = argv[arg];
        arg++;
      }
    }
    else {
      puts("Usage: tftpd [option]\n"
           " --version\n"
           " --logfile [file]\n"
           " --pidfile [file]\n"
           " --ipv4\n"
           " --ipv6\n"
           " --port [port]\n"
           " --srcdir [path]");
      return 0;
    }
  }

#ifdef WIN32
  win32_init();
  atexit(win32_cleanup);
#endif

  install_signal_handlers();

  pid = (long)getpid();

#ifdef ENABLE_IPV6
  if(!use_ipv6)
#endif
    sock = socket(AF_INET, SOCK_DGRAM, 0);
#ifdef ENABLE_IPV6
  else
    sock = socket(AF_INET6, SOCK_DGRAM, 0);
#endif

  if(CURL_SOCKET_BAD == sock) {
    error = SOCKERRNO;
    logmsg("Error creating socket: (%d) %s",
           error, strerror(error));
    result = 1;
    goto tftpd_cleanup;
  }

  flag = 1;
  if (0 != setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
            (void *)&flag, sizeof(flag))) {
    error = SOCKERRNO;
    logmsg("setsockopt(SO_REUSEADDR) failed with error: (%d) %s",
           error, strerror(error));
    result = 1;
    goto tftpd_cleanup;
  }

#ifdef ENABLE_IPV6
  if(!use_ipv6) {
#endif
    memset(&me, 0, sizeof(me));
    me.sin_family = AF_INET;
    me.sin_addr.s_addr = INADDR_ANY;
    me.sin_port = htons(port);
    rc = bind(sock, (struct sockaddr *) &me, sizeof(me));
#ifdef ENABLE_IPV6
  }
  else {
    memset(&me6, 0, sizeof(me6));
    me6.sin6_family = AF_INET6;
    me6.sin6_addr = in6addr_any;
    me6.sin6_port = htons(port);
    rc = bind(sock, (struct sockaddr *) &me6, sizeof(me6));
  }
#endif /* ENABLE_IPV6 */
  if(0 != rc) {
    error = SOCKERRNO;
    logmsg("Error binding socket on port %hu: (%d) %s",
           port, error, strerror(error));
    result = 1;
    goto tftpd_cleanup;
  }

  wrotepidfile = write_pidfile(pidname);
  if(!wrotepidfile) {
    result = 1;
    goto tftpd_cleanup;
  }

  logmsg("Running %s version on port UDP/%d", ipv_inuse, (int)port);

  for (;;) {
    fromlen = sizeof(from);
    n = (ssize_t)recvfrom(sock, buf, sizeof(buf), 0,
                          (struct sockaddr *)&from, &fromlen);
    if(got_exit_signal)
      break;
    if (n < 0) {
      logmsg("recvfrom");
      result = 3;
      break;
    }

    set_advisor_read_lock(SERVERLOGS_LOCK);
    serverlogslocked = 1;

    from.sin_family = AF_INET;

    peer = socket(AF_INET, SOCK_DGRAM, 0);
    if(CURL_SOCKET_BAD == peer) {
      logmsg("socket");
      result = 2;
      break;
    }

    if (connect(peer, (struct sockaddr *)&from, sizeof(from)) < 0) {
      logmsg("connect: fail");
      result = 1;
      break;
    }
    maxtimeout = 5*TIMEOUT;

    tp = (struct tftphdr *)buf;
    tp->th_opcode = ntohs(tp->th_opcode);
    if (tp->th_opcode == opcode_RRQ || tp->th_opcode == opcode_WRQ) {
      memset(&test, 0, sizeof(test));
      if (do_tftp(&test, tp, n) < 0)
        break;
      if(test.buffer)
        free(test.buffer);
    }
    sclose(peer);
    peer = CURL_SOCKET_BAD;

    if(test.ofile > 0) {
      close(test.ofile);
      test.ofile = 0;
    }

    if(got_exit_signal)
      break;

    if(serverlogslocked) {
      serverlogslocked = 0;
      clear_advisor_read_lock(SERVERLOGS_LOCK);
    }

    logmsg("end of one transfer");

  }

tftpd_cleanup:

  if(test.ofile > 0)
    close(test.ofile);

  if((peer != sock) && (peer != CURL_SOCKET_BAD))
    sclose(peer);

  if(sock != CURL_SOCKET_BAD)
    sclose(sock);

  if(got_exit_signal)
    logmsg("signalled to die");

  if(wrotepidfile)
    unlink(pidname);

  if(serverlogslocked) {
    serverlogslocked = 0;
    clear_advisor_read_lock(SERVERLOGS_LOCK);
  }

  restore_signal_handlers();

  if(got_exit_signal) {
    logmsg("========> %s tftpd (port: %d pid: %ld) exits with signal (%d)",
           ipv_inuse, (int)port, pid, exit_signal);
    /*
     * To properly set the return status of the process we
     * must raise the same signal SIGINT or SIGTERM that we
     * caught and let the old handler take care of it.
     */
    raise(exit_signal);
  }

  logmsg("========> tftpd quits");
  return result;
}

/*
 * Handle initial connection protocol.
 */
static int do_tftp(struct testcase *test, struct tftphdr *tp, ssize_t size)
{
  char *cp;
  int first = 1, ecode;
  struct formats *pf;
  char *filename, *mode = NULL;
  int error;
  FILE *server;

  /* Open request dump file. */
  server = fopen(REQUEST_DUMP, "ab");
  if(!server) {
    error = ERRNO;
    logmsg("fopen() failed with error: %d %s", error, strerror(error));
    logmsg("Error opening file: %s", REQUEST_DUMP);
    return -1;
  }

  /* store input protocol */
  fprintf(server, "opcode: %x\n", tp->th_opcode);

  cp = (char *)&tp->th_stuff;
  filename = cp;
again:
  while (cp < buf + size) {
    if (*cp == '\0')
      break;
    cp++;
  }
  if (*cp) {
    nak(EBADOP);
    fclose(server);
    return 3;
  }
  if (first) {
    mode = ++cp;
    first = 0;
    goto again;
  }
  /* store input protocol */
  fprintf(server, "filename: %s\n", filename);

  for (cp = mode; cp && *cp; cp++)
    if(ISUPPER(*cp))
      *cp = (char)tolower((int)*cp);

  /* store input protocol */
  fprintf(server, "mode: %s\n", mode);
  fclose(server);

  for (pf = formata; pf->f_mode; pf++)
    if (strcmp(pf->f_mode, mode) == 0)
      break;
  if (!pf->f_mode) {
    nak(EBADOP);
    return 2;
  }
  ecode = validate_access(test, filename, tp->th_opcode);
  if (ecode) {
    nak(ecode);
    return 1;
  }
  if (tp->th_opcode == opcode_WRQ)
    recvtftp(test, pf);
  else
    sendtftp(test, pf);

  return 0;
}

/*
 * Validate file access.
 */
static int validate_access(struct testcase *test,
                           const char *filename, int mode)
{
  char *ptr;
  long testno, partno;
  int error;
  char partbuf[80]="data";

  logmsg("trying to get file: %s mode %x", filename, mode);

  if(!strncmp("verifiedserver", filename, 14)) {
    char weare[128];
    size_t count = sprintf(weare, "WE ROOLZ: %ld\r\n", (long)getpid());

    logmsg("Are-we-friendly question received");
    test->buffer = strdup(weare);
    test->rptr = test->buffer; /* set read pointer */
    test->bufsize = count;    /* set total count */
    test->rcount = count;     /* set data left to read */
    return 0; /* fine */
  }

  /* find the last slash */
  ptr = strrchr(filename, '/');

  if(ptr) {
    char *file;

    ptr++; /* skip the slash */

    /* skip all non-numericals following the slash */
    while(*ptr && !ISDIGIT(*ptr))
      ptr++;

    /* get the number */
    testno = strtol(ptr, &ptr, 10);

    if(testno > 10000) {
      partno = testno % 10000;
      testno /= 10000;
    }
    else
      partno = 0;


    logmsg("requested test number %ld part %ld", testno, partno);

    test->num = testno;

    file = test2file(testno);

    if(0 != partno)
      sprintf(partbuf, "data%ld", partno);

    if(file) {
      FILE *stream=fopen(file, "rb");
      if(!stream) {
        error = ERRNO;
        logmsg("fopen() failed with error: %d %s", error, strerror(error));
        logmsg("Error opening file: %s", file);
        logmsg("Couldn't open test file: %s", file);
        return EACCESS;
      }
      else {
        size_t count;
        error = getpart(&test->buffer, &count, "reply", partbuf, stream);
        fclose(stream);
        if(error) {
          logmsg("getpart() failed with error: %d", error);
          return EACCESS;
        }
        if(test->buffer) {
          test->rptr = test->buffer; /* set read pointer */
          test->bufsize = count;    /* set total count */
          test->rcount = count;     /* set data left to read */
        }
        else
          return EACCESS;
      }

    }
    else
      return EACCESS;
  }
  else {
    logmsg("no slash found in path");
    return EACCESS; /* failure */
  }

  logmsg("file opened and all is good");
  return 0;
}

/*
 * Send the requested file.
 */
static void sendtftp(struct testcase *test, struct formats *pf)
{
  int size;
  ssize_t n;
  sendblock = 1;
#if defined(HAVE_ALARM) && defined(SIGALRM)
  mysignal(SIGALRM, timer);
#endif
  sdp = r_init();
  sap = (struct tftphdr *)ackbuf;
  do {
    size = readit(test, &sdp, pf->f_convert);
    if (size < 0) {
      nak(ERRNO + 100);
      return;
    }
    sdp->th_opcode = htons((u_short)opcode_DATA);
    sdp->th_block = htons((u_short)sendblock);
    timeout = 0;
#ifdef HAVE_SIGSETJMP
    (void) sigsetjmp(timeoutbuf, 1);
#endif
    send_data:
    if (swrite(peer, sdp, size + 4) != size + 4) {
      logmsg("write");
      return;
    }
    read_ahead(test, pf->f_convert);
    for ( ; ; ) {
#ifdef HAVE_ALARM
      alarm(rexmtval);        /* read the ack */
#endif
      n = sread(peer, ackbuf, sizeof (ackbuf));
#ifdef HAVE_ALARM
      alarm(0);
#endif
      if(got_exit_signal)
        return;
      if (n < 0) {
        logmsg("read: fail");
        return;
      }
      sap->th_opcode = ntohs((u_short)sap->th_opcode);
      sap->th_block = ntohs((u_short)sap->th_block);

      if (sap->th_opcode == opcode_ERROR) {
        logmsg("got ERROR");
        return;
      }

      if (sap->th_opcode == opcode_ACK) {
        if (sap->th_block == sendblock) {
          break;
        }
        /* Re-synchronize with the other side */
        (void) synchnet(peer);
        if (sap->th_block == (sendblock-1)) {
          goto send_data;
        }
      }

    }
    sendblock++;
  } while (size == SEGSIZE);
}

/*
 * Receive a file.
 */
static void recvtftp(struct testcase *test, struct formats *pf)
{
  ssize_t n, size;
  recvblock = 0;
#if defined(HAVE_ALARM) && defined(SIGALRM)
  mysignal(SIGALRM, timer);
#endif
  rdp = w_init();
  rap = (struct tftphdr *)ackbuf;
  do {
    timeout = 0;
    rap->th_opcode = htons((u_short)opcode_ACK);
    rap->th_block = htons((u_short)recvblock);
    recvblock++;
#ifdef HAVE_SIGSETJMP
    (void) sigsetjmp(timeoutbuf, 1);
#endif
send_ack:
    if (swrite(peer, ackbuf, 4) != 4) {
      logmsg("write: fail\n");
      goto abort;
    }
    write_behind(test, pf->f_convert);
    for ( ; ; ) {
#ifdef HAVE_ALARM
      alarm(rexmtval);
#endif
      n = sread(peer, rdp, PKTSIZE);
#ifdef HAVE_ALARM
      alarm(0);
#endif
      if(got_exit_signal)
        goto abort;
      if (n < 0) {                       /* really? */
        logmsg("read: fail\n");
        goto abort;
      }
      rdp->th_opcode = ntohs((u_short)rdp->th_opcode);
      rdp->th_block = ntohs((u_short)rdp->th_block);
      if (rdp->th_opcode == opcode_ERROR)
        goto abort;
      if (rdp->th_opcode == opcode_DATA) {
        if (rdp->th_block == recvblock) {
          break;                         /* normal */
        }
        /* Re-synchronize with the other side */
        (void) synchnet(peer);
        if (rdp->th_block == (recvblock-1))
          goto send_ack;                 /* rexmit */
      }
    }

    size = writeit(test, &rdp, (int)(n - 4), pf->f_convert);
    if (size != (n-4)) {                 /* ahem */
      if (size < 0)
        nak(ERRNO + 100);
      else
        nak(ENOSPACE);
      goto abort;
    }
  } while (size == SEGSIZE);
  write_behind(test, pf->f_convert);

  rap->th_opcode = htons((u_short)opcode_ACK);  /* send the "final" ack */
  rap->th_block = htons((u_short)recvblock);
  (void) swrite(peer, ackbuf, 4);
#if defined(HAVE_ALARM) && defined(SIGALRM)
  mysignal(SIGALRM, justtimeout);        /* just abort read on timeout */
  alarm(rexmtval);
#endif
  n = sread(peer, buf, sizeof(buf));     /* normally times out and quits */
#ifdef HAVE_ALARM
  alarm(0);
#endif
  if(got_exit_signal)
    goto abort;
  if (n >= 4 &&                          /* if read some data */
      rdp->th_opcode == opcode_DATA &&   /* and got a data block */
      recvblock == rdp->th_block) {      /* then my last ack was lost */
    (void) swrite(peer, ackbuf, 4);      /* resend final ack */
  }
abort:
  return;
}

/*
 * Send a nak packet (error message).  Error code passed in is one of the
 * standard TFTP codes, or a UNIX errno offset by 100.
 */
static void nak(int error)
{
  struct tftphdr *tp;
  int length;
  struct errmsg *pe;

  tp = (struct tftphdr *)buf;
  tp->th_opcode = htons((u_short)opcode_ERROR);
  tp->th_code = htons((u_short)error);
  for (pe = errmsgs; pe->e_code >= 0; pe++)
    if (pe->e_code == error)
      break;
  if (pe->e_code < 0) {
    pe->e_msg = strerror(error - 100);
    tp->th_code = EUNDEF;   /* set 'undef' errorcode */
  }
  strcpy(tp->th_msg, pe->e_msg);
  length = (int)strlen(pe->e_msg);
  tp->th_msg[length] = '\0';
  length += 5;
  if (swrite(peer, buf, length) != length)
    logmsg("nak: fail\n");
}