aboutsummaryrefslogtreecommitdiff
path: root/lib/http.c
blob: 1f17b9c003e14685cf74270c7d4a7334b104d9f3 (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
/*****************************************************************************
 *                                  _   _ ____  _     
 *  Project                     ___| | | |  _ \| |    
 *                             / __| | | | |_) | |    
 *                            | (__| |_| |  _ <| |___ 
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 2000, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * In order to be useful for every potential user, curl and libcurl are
 * dual-licensed under the MPL and the MIT/X-derivate licenses.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the MPL or the MIT/X-derivate
 * licenses. You may pick one of these licenses.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * $Id$
 *****************************************************************************/

#include "setup.h"

/* -- WIN32 approved -- */
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <errno.h>


#ifdef NEED_REENTRANT
#define _REENTRANT /* Necessary to use in Solaris, since the silly guys at Sun
                      made the localtime_r() prototype dependent on it (or
                      _POSIX_C_SOURCE or _POSIX_PTHREAD_SEMANTICS). */
#endif

#if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
#include <winsock.h>
#include <time.h>
#include <io.h>
#else
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#include <sys/time.h>

#ifdef HAVE_TIME_H
#ifdef TIME_WITH_SYS_TIME
#include <time.h>
#endif
#endif

#include <sys/resource.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <netdb.h>
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_NET_IF_H
#include <net/if.h>
#endif
#include <sys/ioctl.h>
#include <signal.h>

#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif

#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif


#endif

#include "urldata.h"
#include <curl/curl.h>
#include "transfer.h"
#include "sendf.h"
#include "formdata.h"
#include "progress.h"
#include "base64.h"
#include "cookie.h"
#include "strequal.h"
#include "ssluse.h"

#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>

/* The last #include file should be: */
#ifdef MALLOCDEBUG
#include "memdebug.h"
#endif

/* ------------------------------------------------------------------------- */
/*
 * The add_buffer series of functions are used to build one large memory chunk
 * from repeated function invokes. Used so that the entire HTTP request can
 * be sent in one go.
 */
static CURLcode
 add_buffer(send_buffer *in, void *inptr, size_t size);

/*
 * add_buffer_init() returns a fine buffer struct
 */
static
send_buffer *add_buffer_init(void)
{
  send_buffer *blonk;
  blonk=(send_buffer *)malloc(sizeof(send_buffer));
  if(blonk) {
    memset(blonk, 0, sizeof(send_buffer));
    return blonk;
  }
  return NULL; /* failed, go home */
}

/*
 * add_buffer_send() sends a buffer and frees all associated memory.
 */
static
size_t add_buffer_send(int sockfd, struct connectdata *conn, send_buffer *in)
{
  size_t amount;
  if(conn->data->bits.verbose) {
    fputs("> ", conn->data->err);
    /* this data _may_ contain binary stuff */
    fwrite(in->buffer, in->size_used, 1, conn->data->err);
  }

  Curl_write(conn, sockfd, in->buffer, in->size_used, &amount);

  if(in->buffer)
    free(in->buffer);
  free(in);

  return amount;
}


/* 
 * add_bufferf() builds a buffer from the formatted input
 */
static
CURLcode add_bufferf(send_buffer *in, char *fmt, ...)
{
  CURLcode result = CURLE_OUT_OF_MEMORY;
  char *s;
  va_list ap;
  va_start(ap, fmt);
  s = vaprintf(fmt, ap); /* this allocs a new string to append */
  va_end(ap);

  if(s) {
    result = add_buffer(in, s, strlen(s));
    free(s);
  }
  return result;
}

/*
 * add_buffer() appends a memory chunk to the existing one
 */
static
CURLcode add_buffer(send_buffer *in, void *inptr, size_t size)
{
  char *new_rb;
  int new_size;

  if(size > 0) {
    if(!in->buffer ||
       ((in->size_used + size) > (in->size_max - 1))) {
      new_size = (in->size_used+size)*2;
      if(in->buffer)
        /* we have a buffer, enlarge the existing one */
        new_rb = (char *)realloc(in->buffer, new_size);
      else
        /* create a new buffer */
        new_rb = (char *)malloc(new_size);

      if(!new_rb)
        return CURLE_OUT_OF_MEMORY;

      in->buffer = new_rb;
      in->size_max = new_size;
    }
    memcpy(&in->buffer[in->size_used], inptr, size);
      
    in->size_used += size;
  }

  return CURLE_OK;
}

/* end of the add_buffer functions */
/* ------------------------------------------------------------------------- */

/*
 * Read everything until a newline.
 */

static
int GetLine(int sockfd, char *buf, struct connectdata *conn)
{
  ssize_t nread;
  int read_rc=1;
  char *ptr;
  struct UrlData *data=conn->data;

  ptr=buf;

  /* get us a full line, terminated with a newline */
  for(nread=0;
      (nread<BUFSIZE) && read_rc;
      nread++, ptr++) {
    if((CURLE_OK != Curl_read(conn, sockfd, ptr, 1, &nread)) ||
       (nread <= 0) ||
       (*ptr == '\n'))
      break;
  }
  *ptr=0; /* zero terminate */
  
  if(data->bits.verbose) {
    fputs("< ", data->err);
    fwrite(buf, 1, nread, data->err);
    fputs("\n", data->err);
  }
  return nread>0?nread:0;
}



/*
 * This function checks the linked list of custom HTTP headers for a particular
 * header (prefix).
 */
bool static checkheaders(struct UrlData *data, char *thisheader)
{
  struct curl_slist *head;
  size_t thislen = strlen(thisheader);

  for(head = data->headers; head; head=head->next) {
    if(strnequal(head->data, thisheader, thislen)) {
      return TRUE;
    }
  }
  return FALSE;
}

/*
 * ConnectHTTPProxyTunnel() requires that we're connected to a HTTP proxy. This
 * function will issue the necessary commands to get a seamless tunnel through
 * this proxy. After that, the socket can be used just as a normal socket.
 */

CURLcode Curl_ConnectHTTPProxyTunnel(struct connectdata *conn,
                                     int tunnelsocket,
                                     char *hostname, int remote_port)
{
  int httperror=0;
  int subversion=0;
  struct UrlData *data=conn->data;

  infof(data, "Establish HTTP proxy tunnel to %s:%d\n", hostname, remote_port);

  /* OK, now send the connect request to the proxy */
  Curl_sendf(tunnelsocket, conn,
             "CONNECT %s:%d HTTP/1.0\015\012"
             "%s"
             "%s"
             "\r\n",
             hostname, remote_port,
             (conn->bits.proxy_user_passwd)?conn->allocptr.proxyuserpwd:"",
             (data->useragent?conn->allocptr.uagent:"")
             );

  /* wait for the proxy to send us a HTTP/1.0 200 OK header */
  while(GetLine(tunnelsocket, data->buffer, conn)) {
    if('\r' == data->buffer[0])
      break; /* end of headers */
    if(2 == sscanf(data->buffer, "HTTP/1.%d %d",
                   &subversion,
                   &httperror)) {
      ;
    }
  }
  if(200 != httperror) {
    if(407 == httperror)
      /* Added Nov 6 1998 */
      failf(data, "Proxy requires authorization!");
    else 
      failf(data, "Received error code %d from proxy", httperror);
    return CURLE_READ_ERROR;
  }

  infof (data, "Proxy replied to CONNECT request\n");
  return CURLE_OK;
}

/*
 * HTTP stuff to do at connect-time.
 */
CURLcode Curl_http_connect(struct connectdata *conn)
{
  struct UrlData *data;
  CURLcode result;

  data=conn->data;

  /* If we are not using a proxy and we want a secure connection,
   * perform SSL initialization & connection now.
   * If using a proxy with https, then we must tell the proxy to CONNECT
   * us to the host we want to talk to.  Only after the connect
   * has occured, can we start talking SSL
   */
  if (conn->protocol & PROT_HTTPS) {
    if (data->bits.httpproxy) {
      /* HTTPS through a proxy can only be done with a tunnel */
      result = Curl_ConnectHTTPProxyTunnel(conn, conn->firstsocket,
                                           conn->hostname, conn->remote_port);
      if(CURLE_OK != result)
        return result;
    }

    /* now, perform the SSL initialization for this socket */
    if(Curl_SSLConnect(conn))
      return CURLE_SSL_CONNECT_ERROR;
  }

  if(conn->bits.user_passwd && !data->bits.this_is_a_follow) {
    /* Authorization: is requested, this is not a followed location, get the
       original host name */
    data->auth_host = strdup(conn->hostname);
  }

  return CURLE_OK;
}

/* called from curl_close() when this struct is about to get wasted, free
   protocol-specific resources */
CURLcode Curl_http_close(struct connectdata *conn)
{
  if(conn->data->auth_host)
    free(conn->data->auth_host);
  return CURLE_OK;
}

CURLcode Curl_http_done(struct connectdata *conn)
{
  struct UrlData *data;
  long *bytecount = &conn->bytecount;
  struct HTTP *http;

  data=conn->data;
  http=conn->proto.http;

  if(data->bits.http_formpost) {
    *bytecount = http->readbytecount + http->writebytecount;
      
    Curl_FormFree(http->sendit); /* Now free that whole lot */

    data->fread = http->storefread; /* restore */
    data->in = http->in; /* restore */
  }
  else if(data->bits.http_put) {
    *bytecount = http->readbytecount + http->writebytecount;
  }

  return CURLE_OK;
}


CURLcode Curl_http(struct connectdata *conn)
{
  struct UrlData *data=conn->data;
  char *buf = data->buffer; /* this is a short cut to the buffer */
  CURLcode result=CURLE_OK;
  struct HTTP *http;
  struct Cookie *co=NULL; /* no cookies from start */
  char *ppath = conn->ppath; /* three previous function arguments */
  char *host = conn->name;
  long *bytecount = &conn->bytecount;

  if(!conn->proto.http) {
    /* Only allocate this struct if we don't already have it! */

    http = (struct HTTP *)malloc(sizeof(struct HTTP));
    if(!http)
      return CURLE_OUT_OF_MEMORY;
    memset(http, 0, sizeof(struct HTTP));
    conn->proto.http = http;
  }
  else
    http = conn->proto.http;

  /* We default to persistant connections */
  conn->bits.close = FALSE;

  if ( (conn->protocol&(PROT_HTTP|PROT_FTP)) &&
       data->bits.upload) {
    data->bits.http_put=1;
  }
  
  /* The User-Agent string has been built in url.c already, because it might
     have been used in the proxy connect, but if we have got a header with
     the user-agent string specified, we erase the previously made string
     here. */
  if(checkheaders(data, "User-Agent:") && conn->allocptr.uagent) {
    free(conn->allocptr.uagent);
    conn->allocptr.uagent=NULL;
  }

  if((conn->bits.user_passwd) && !checkheaders(data, "Authorization:")) {
    char *authorization;

    /* To prevent the user+password to get sent to other than the original
       host due to a location-follow, we do some weirdo checks here */
    if(!data->bits.this_is_a_follow ||
       !data->auth_host ||
       strequal(data->auth_host, conn->hostname)) {
      sprintf(data->buffer, "%s:%s", data->user, data->passwd);
      if(Curl_base64_encode(data->buffer, strlen(data->buffer),
                            &authorization) >= 0) {
        if(conn->allocptr.userpwd)
          free(conn->allocptr.userpwd);
        conn->allocptr.userpwd = aprintf( "Authorization: Basic %s\015\012",
                                     authorization);
        free(authorization);
      }
    }
  }
  if((data->bits.http_set_referer) && !checkheaders(data, "Referer:")) {
    if(conn->allocptr.ref)
      free(conn->allocptr.ref);
    conn->allocptr.ref = aprintf("Referer: %s\015\012", data->referer);
  }
  if(data->cookie && !checkheaders(data, "Cookie:")) {
    if(conn->allocptr.cookie)
      free(conn->allocptr.cookie);
    conn->allocptr.cookie = aprintf("Cookie: %s\015\012", data->cookie);
  }

  if(data->cookies) {
    co = Curl_cookie_getlist(data->cookies,
                             host,
                             ppath,
                             conn->protocol&PROT_HTTPS?TRUE:FALSE);
  }
  if ((data->bits.httpproxy) && !(conn->protocol&PROT_HTTPS))  {
    /* The path sent to the proxy is in fact the entire URL */
    ppath = data->url;
  }
  if(data->bits.http_formpost) {
    /* we must build the whole darned post sequence first, so that we have
       a size of the whole shebang before we start to send it */
    http->sendit = Curl_getFormData(data->httppost, &http->postsize);
  }

  if(!checkheaders(data, "Host:")) {
    /* if ptr_host is already set, it is almost OK since we only re-use
       connections to the very same host and port, but when we use a HTTP
       proxy we have a persistant connect and yet we must change the Host:
       header! */

    if(conn->allocptr.host)
      free(conn->allocptr.host);

    if(((conn->protocol&PROT_HTTPS) && (conn->remote_port == PORT_HTTPS)) ||
       (!(conn->protocol&PROT_HTTPS) && (conn->remote_port == PORT_HTTP)) )
      /* If (HTTPS on port 443) OR (non-HTTPS on port 80) then don't include
         the port number in the host string */
      conn->allocptr.host = aprintf("Host: %s\r\n", host);
    else
      conn->allocptr.host = aprintf("Host: %s:%d\r\n", host,
                                    conn->remote_port);
  }

  if(!checkheaders(data, "Pragma:"))
    http->p_pragma = "Pragma: no-cache\r\n";

  if(!checkheaders(data, "Accept:"))
    http->p_accept = "Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, */*\r\n";

  if((data->bits.http_post ||
      data->bits.http_formpost ||
      data->bits.http_put) &&
     conn->resume_from) {
    /**********************************************************************
     * Resuming upload in HTTP means that we PUT or POST and that we have
     * got a resume_from value set. The resume value has already created
     * a Range: header that will be passed along. We need to "fast forward"
     * the file the given number of bytes and decrease the assume upload
     * file size before we continue this venture in the dark lands of HTTP.
     *********************************************************************/
   
    if(conn->resume_from < 0 ) {
      /*
       * This is meant to get the size of the present remote-file by itself.
       * We don't support this now. Bail out!
       */
       conn->resume_from = 0;
    }

    if(conn->resume_from) {
      /* do we still game? */
      int passed=0;

      /* Now, let's read off the proper amount of bytes from the
         input. If we knew it was a proper file we could've just
         fseek()ed but we only have a stream here */
      do {
        int readthisamountnow = (conn->resume_from - passed);
        int actuallyread;

        if(readthisamountnow > BUFSIZE)
          readthisamountnow = BUFSIZE;

        actuallyread =
          data->fread(data->buffer, 1, readthisamountnow, data->in);

        passed += actuallyread;
        if(actuallyread != readthisamountnow) {
          failf(data, "Could only read %d bytes from the input\n",
                passed);
          return CURLE_READ_ERROR;
        }
      } while(passed != conn->resume_from); /* loop until done */

      /* now, decrease the size of the read */
      if(data->infilesize>0) {
        data->infilesize -= conn->resume_from;

        if(data->infilesize <= 0) {
          failf(data, "File already completely uploaded\n");
          return CURLE_PARTIAL_FILE;
        }
      }
      /* we've passed, proceed as normal */
    }
  }
  if(conn->bits.use_range) {
    /*
     * A range is selected. We use different headers whether we're downloading
     * or uploading and we always let customized headers override our internal
     * ones if any such are specified.
     */
    if((data->httpreq == HTTPREQ_GET) &&
       !checkheaders(data, "Range:")) {
      conn->allocptr.rangeline = aprintf("Range: bytes=%s\r\n", conn->range);
    }
    else if((data->httpreq != HTTPREQ_GET) &&
            !checkheaders(data, "Content-Range:")) {

      if(conn->resume_from) {
        /* This is because "resume" was selected */
        long total_expected_size= conn->resume_from + data->infilesize;
        conn->allocptr.rangeline = aprintf("Content-Range: bytes %s%ld/%ld\r\n",
                                      conn->range, total_expected_size-1,
                                      total_expected_size);
      }
      else {
        /* Range was selected and then we just pass the incoming range and 
           append total size */
        conn->allocptr.rangeline = aprintf("Content-Range: bytes %s/%d\r\n",
                                      conn->range, data->infilesize);
      }
    }
  }

  do {
    send_buffer *req_buffer;
    struct curl_slist *headers=data->headers;

    /* initialize a dynamic send-buffer */
    req_buffer = add_buffer_init();

    /* add the main request stuff */
    add_bufferf(req_buffer,
                "%s " /* GET/HEAD/POST/PUT */
                "%s HTTP/1.1\r\n" /* path */
                "%s" /* proxyuserpwd */
                "%s" /* userpwd */
                "%s" /* range */
                "%s" /* user agent */
                "%s" /* cookie */
                "%s" /* host */
                "%s" /* pragma */
                "%s" /* accept */
                "%s", /* referer */

                data->customrequest?data->customrequest:
                (data->bits.no_body?"HEAD":
                 (data->bits.http_post || data->bits.http_formpost)?"POST":
                 (data->bits.http_put)?"PUT":"GET"),
                ppath,
                (conn->bits.proxy_user_passwd &&
                 conn->allocptr.proxyuserpwd)?conn->allocptr.proxyuserpwd:"",
                (conn->bits.user_passwd && conn->allocptr.userpwd)?
                conn->allocptr.userpwd:"",
                (conn->bits.use_range && conn->allocptr.rangeline)?
                conn->allocptr.rangeline:"",
                (data->useragent && *data->useragent && conn->allocptr.uagent)?
                conn->allocptr.uagent:"",
                (conn->allocptr.cookie?conn->allocptr.cookie:""), /* Cookie: <data> */
                (conn->allocptr.host?conn->allocptr.host:""), /* Host: host */
                http->p_pragma?http->p_pragma:"",
                http->p_accept?http->p_accept:"",
                (data->bits.http_set_referer && conn->allocptr.ref)?conn->allocptr.ref:"" /* Referer: <data> <CRLF> */
                );

    if(co) {
      int count=0;
      struct Cookie *store=co;
      /* now loop through all cookies that matched */
      while(co) {
        if(co->value && strlen(co->value)) {
          if(0 == count) {
            add_bufferf(req_buffer, "Cookie: ");
          }
          add_bufferf(req_buffer,
                      "%s%s=%s", count?"; ":"", co->name, co->value);
          count++;
        }
        co = co->next; /* next cookie please */
      }
      if(count) {
        add_buffer(req_buffer, "\r\n", 2);
      }
      Curl_cookie_freelist(store); /* free the cookie list */
      co=NULL;
    }

    if(data->timecondition) {
      struct tm *thistime;

      /* Phil Karn (Fri, 13 Apr 2001) pointed out that the If-Modified-Since
       * header family should have their times set in GMT as RFC2616 defines:
       * "All HTTP date/time stamps MUST be represented in Greenwich Mean Time
       * (GMT), without exception. For the purposes of HTTP, GMT is exactly
       * equal to UTC (Coordinated Universal Time)." (see page 20 of RFC2616).
       */

#ifdef HAVE_LOCALTIME_R
      /* thread-safe version */
      /* We assume that the presense of localtime_r() proves the presense
         of gmtime_r() which is a bit ugly but might work */
      struct tm keeptime;
      thistime = (struct tm *)gmtime_r(&data->timevalue, &keeptime);
#else
      thistime = gmtime(&data->timevalue);
#endif
      if(NULL == thistime) {
        failf(data, "localtime() failed!");
        return CURLE_OUT_OF_MEMORY;
      }

#ifdef HAVE_STRFTIME
      /* format: "Tue, 15 Nov 1994 12:45:26 GMT" */
      strftime(buf, BUFSIZE-1, "%a, %d %b %Y %H:%M:%S %Z", thistime);
#else
      /* TODO: Right, we *could* write a replacement here */
      strcpy(buf, "no strftime() support");
#endif
      switch(data->timecondition) {
      case TIMECOND_IFMODSINCE:
      default:
        add_bufferf(req_buffer,
                    "If-Modified-Since: %s\r\n", buf);
        break;
      case TIMECOND_IFUNMODSINCE:
        add_bufferf(req_buffer,
                    "If-Unmodified-Since: %s\r\n", buf);
        break;
      case TIMECOND_LASTMOD:
        add_bufferf(req_buffer,
                    "Last-Modified: %s\r\n", buf);
        break;
      }
    }

    while(headers) {
      char *ptr = strchr(headers->data, ':');
      if(ptr) {
        /* we require a colon for this to be a true header */

        ptr++; /* pass the colon */
        while(*ptr && isspace((int)*ptr))
          ptr++;

        if(*ptr) {
          /* only send this if the contents was non-blank */

          add_bufferf(req_buffer, "%s\r\n", headers->data);
        }
      }
      headers = headers->next;
    }

    if(data->bits.http_formpost) {
      if(Curl_FormInit(&http->form, http->sendit)) {
        failf(data, "Internal HTTP POST error!\n");
        return CURLE_HTTP_POST_ERROR;
      }

      http->storefread = data->fread; /* backup */
      http->in = data->in; /* backup */
          
      data->fread =
        (size_t (*)(char *, size_t, size_t, FILE *))
        Curl_FormReader; /* set the read function to read from the
                            generated form data */
      data->in = (FILE *)&http->form;

      add_bufferf(req_buffer,
                  "Content-Length: %d\r\n", http->postsize-2);

      /* set upload size to the progress meter */
      Curl_pgrsSetUploadSize(data, http->postsize);

      data->request_size = 
        add_buffer_send(conn->firstsocket, conn, req_buffer);
      result = Curl_Transfer(conn, conn->firstsocket, -1, TRUE,
                        &http->readbytecount,
                          conn->firstsocket,
                        &http->writebytecount);
      if(result) {
        Curl_FormFree(http->sendit); /* free that whole lot */
        return result;
      }
    }
    else if(data->bits.http_put) {
      /* Let's PUT the data to the server! */

      if(data->infilesize>0) {
        add_bufferf(req_buffer,
                    "Content-Length: %d\r\n\r\n", /* file size */
                    data->infilesize );
      }
      else
        add_bufferf(req_buffer, "\015\012");

      /* set the upload size to the progress meter */
      Curl_pgrsSetUploadSize(data, data->infilesize);

      /* this sends the buffer and frees all the buffer resources */
      data->request_size = 
        add_buffer_send(conn->firstsocket, conn, req_buffer);

      /* prepare for transfer */
      result = Curl_Transfer(conn, conn->firstsocket, -1, TRUE,
                        &http->readbytecount,
                        conn->firstsocket,
                        &http->writebytecount);
      if(result)
        return result;
      
    }
    else {
      if(data->bits.http_post) {
        /* this is the simple POST, using x-www-form-urlencoded style */

        if(!checkheaders(data, "Content-Length:"))
          /* we allow replacing this header, although it isn't very wise to
             actually set your own */
          add_bufferf(req_buffer,
                      "Content-Length: %d\r\n",
                      (data->postfieldsize?data->postfieldsize:
                       strlen(data->postfields)) );

        if(!checkheaders(data, "Content-Type:"))
          add_bufferf(req_buffer,
                      "Content-Type: application/x-www-form-urlencoded\r\n");

        /* and here comes the actual data */
        if(data->postfieldsize) {
          add_buffer(req_buffer, "\r\n", 2);
          add_buffer(req_buffer, data->postfields,
                     data->postfieldsize);
          add_buffer(req_buffer, "\r\n", 2);
        }
        else {
          add_bufferf(req_buffer,
                      "\r\n"
                      "%s\r\n",
                      data->postfields );
        }
      }
      else
        add_buffer(req_buffer, "\r\n", 2);

      /* issue the request */
      data->request_size = 
        add_buffer_send(conn->firstsocket, conn, req_buffer);

      /* HTTP GET/HEAD download: */
      result = Curl_Transfer(conn, conn->firstsocket, -1, TRUE, bytecount,
                        -1, NULL); /* nothing to upload */
    }
    if(result)
      return result;
  } while (0); /* this is just a left-over from the multiple document download
                  attempts */

  return CURLE_OK;
}