Annotation of embedaddon/curl/lib/transfer.c, revision 1.1.1.1

1.1       misho       1: /***************************************************************************
                      2:  *                                  _   _ ____  _
                      3:  *  Project                     ___| | | |  _ \| |
                      4:  *                             / __| | | | |_) | |
                      5:  *                            | (__| |_| |  _ <| |___
                      6:  *                             \___|\___/|_| \_\_____|
                      7:  *
                      8:  * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
                      9:  *
                     10:  * This software is licensed as described in the file COPYING, which
                     11:  * you should have received as part of this distribution. The terms
                     12:  * are also available at https://curl.haxx.se/docs/copyright.html.
                     13:  *
                     14:  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
                     15:  * copies of the Software, and permit persons to whom the Software is
                     16:  * furnished to do so, under the terms of the COPYING file.
                     17:  *
                     18:  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
                     19:  * KIND, either express or implied.
                     20:  *
                     21:  ***************************************************************************/
                     22: 
                     23: #include "curl_setup.h"
                     24: #include "strtoofft.h"
                     25: 
                     26: #ifdef HAVE_NETINET_IN_H
                     27: #include <netinet/in.h>
                     28: #endif
                     29: #ifdef HAVE_NETDB_H
                     30: #include <netdb.h>
                     31: #endif
                     32: #ifdef HAVE_ARPA_INET_H
                     33: #include <arpa/inet.h>
                     34: #endif
                     35: #ifdef HAVE_NET_IF_H
                     36: #include <net/if.h>
                     37: #endif
                     38: #ifdef HAVE_SYS_IOCTL_H
                     39: #include <sys/ioctl.h>
                     40: #endif
                     41: #ifdef HAVE_SIGNAL_H
                     42: #include <signal.h>
                     43: #endif
                     44: 
                     45: #ifdef HAVE_SYS_PARAM_H
                     46: #include <sys/param.h>
                     47: #endif
                     48: 
                     49: #ifdef HAVE_SYS_SELECT_H
                     50: #include <sys/select.h>
                     51: #elif defined(HAVE_UNISTD_H)
                     52: #include <unistd.h>
                     53: #endif
                     54: 
                     55: #ifndef HAVE_SOCKET
                     56: #error "We can't compile without socket() support!"
                     57: #endif
                     58: 
                     59: #include "urldata.h"
                     60: #include <curl/curl.h>
                     61: #include "netrc.h"
                     62: 
                     63: #include "content_encoding.h"
                     64: #include "hostip.h"
                     65: #include "transfer.h"
                     66: #include "sendf.h"
                     67: #include "speedcheck.h"
                     68: #include "progress.h"
                     69: #include "http.h"
                     70: #include "url.h"
                     71: #include "getinfo.h"
                     72: #include "vtls/vtls.h"
                     73: #include "select.h"
                     74: #include "multiif.h"
                     75: #include "connect.h"
                     76: #include "non-ascii.h"
                     77: #include "http2.h"
                     78: #include "mime.h"
                     79: #include "strcase.h"
                     80: #include "urlapi-int.h"
                     81: 
                     82: /* The last 3 #include files should be in this order */
                     83: #include "curl_printf.h"
                     84: #include "curl_memory.h"
                     85: #include "memdebug.h"
                     86: 
                     87: #if !defined(CURL_DISABLE_HTTP) || !defined(CURL_DISABLE_SMTP) || \
                     88:     !defined(CURL_DISABLE_IMAP)
                     89: /*
                     90:  * checkheaders() checks the linked list of custom headers for a
                     91:  * particular header (prefix). Provide the prefix without colon!
                     92:  *
                     93:  * Returns a pointer to the first matching header or NULL if none matched.
                     94:  */
                     95: char *Curl_checkheaders(const struct connectdata *conn,
                     96:                         const char *thisheader)
                     97: {
                     98:   struct curl_slist *head;
                     99:   size_t thislen = strlen(thisheader);
                    100:   struct Curl_easy *data = conn->data;
                    101: 
                    102:   for(head = data->set.headers; head; head = head->next) {
                    103:     if(strncasecompare(head->data, thisheader, thislen) &&
                    104:        Curl_headersep(head->data[thislen]) )
                    105:       return head->data;
                    106:   }
                    107: 
                    108:   return NULL;
                    109: }
                    110: #endif
                    111: 
                    112: CURLcode Curl_get_upload_buffer(struct Curl_easy *data)
                    113: {
                    114:   if(!data->state.ulbuf) {
                    115:     data->state.ulbuf = malloc(data->set.upload_buffer_size);
                    116:     if(!data->state.ulbuf)
                    117:       return CURLE_OUT_OF_MEMORY;
                    118:   }
                    119:   return CURLE_OK;
                    120: }
                    121: 
                    122: #ifndef CURL_DISABLE_HTTP
                    123: /*
                    124:  * This function will be called to loop through the trailers buffer
                    125:  * until no more data is available for sending.
                    126:  */
                    127: static size_t Curl_trailers_read(char *buffer, size_t size, size_t nitems,
                    128:                                  void *raw)
                    129: {
                    130:   struct Curl_easy *data = (struct Curl_easy *)raw;
                    131:   Curl_send_buffer *trailers_buf = data->state.trailers_buf;
                    132:   size_t bytes_left = trailers_buf->size_used-data->state.trailers_bytes_sent;
                    133:   size_t to_copy = (size*nitems < bytes_left) ? size*nitems : bytes_left;
                    134:   if(to_copy) {
                    135:     memcpy(buffer,
                    136:            &trailers_buf->buffer[data->state.trailers_bytes_sent],
                    137:            to_copy);
                    138:     data->state.trailers_bytes_sent += to_copy;
                    139:   }
                    140:   return to_copy;
                    141: }
                    142: 
                    143: static size_t Curl_trailers_left(void *raw)
                    144: {
                    145:   struct Curl_easy *data = (struct Curl_easy *)raw;
                    146:   Curl_send_buffer *trailers_buf = data->state.trailers_buf;
                    147:   return trailers_buf->size_used - data->state.trailers_bytes_sent;
                    148: }
                    149: #endif
                    150: 
                    151: /*
                    152:  * This function will call the read callback to fill our buffer with data
                    153:  * to upload.
                    154:  */
                    155: CURLcode Curl_fillreadbuffer(struct connectdata *conn, size_t bytes,
                    156:                              size_t *nreadp)
                    157: {
                    158:   struct Curl_easy *data = conn->data;
                    159:   size_t buffersize = bytes;
                    160:   size_t nread;
                    161: 
                    162:   curl_read_callback readfunc = NULL;
                    163:   void *extra_data = NULL;
                    164: 
                    165: #ifdef CURL_DOES_CONVERSIONS
                    166:   bool sending_http_headers = FALSE;
                    167: 
                    168:   if(conn->handler->protocol&(PROTO_FAMILY_HTTP|CURLPROTO_RTSP)) {
                    169:     const struct HTTP *http = data->req.protop;
                    170: 
                    171:     if(http->sending == HTTPSEND_REQUEST)
                    172:       /* We're sending the HTTP request headers, not the data.
                    173:          Remember that so we don't re-translate them into garbage. */
                    174:       sending_http_headers = TRUE;
                    175:   }
                    176: #endif
                    177: 
                    178: #ifndef CURL_DISABLE_HTTP
                    179:   if(data->state.trailers_state == TRAILERS_INITIALIZED) {
                    180:     struct curl_slist *trailers = NULL;
                    181:     CURLcode result;
                    182:     int trailers_ret_code;
                    183: 
                    184:     /* at this point we already verified that the callback exists
                    185:        so we compile and store the trailers buffer, then proceed */
                    186:     infof(data,
                    187:           "Moving trailers state machine from initialized to sending.\n");
                    188:     data->state.trailers_state = TRAILERS_SENDING;
                    189:     data->state.trailers_buf = Curl_add_buffer_init();
                    190:     if(!data->state.trailers_buf) {
                    191:       failf(data, "Unable to allocate trailing headers buffer !");
                    192:       return CURLE_OUT_OF_MEMORY;
                    193:     }
                    194:     data->state.trailers_bytes_sent = 0;
                    195:     Curl_set_in_callback(data, true);
                    196:     trailers_ret_code = data->set.trailer_callback(&trailers,
                    197:                                                    data->set.trailer_data);
                    198:     Curl_set_in_callback(data, false);
                    199:     if(trailers_ret_code == CURL_TRAILERFUNC_OK) {
                    200:       result = Curl_http_compile_trailers(trailers, &data->state.trailers_buf,
                    201:                                           data);
                    202:     }
                    203:     else {
                    204:       failf(data, "operation aborted by trailing headers callback");
                    205:       *nreadp = 0;
                    206:       result = CURLE_ABORTED_BY_CALLBACK;
                    207:     }
                    208:     if(result) {
                    209:       Curl_add_buffer_free(&data->state.trailers_buf);
                    210:       curl_slist_free_all(trailers);
                    211:       return result;
                    212:     }
                    213:     infof(data, "Successfully compiled trailers.\r\n");
                    214:     curl_slist_free_all(trailers);
                    215:   }
                    216: #endif
                    217: 
                    218:   /* if we are transmitting trailing data, we don't need to write
                    219:      a chunk size so we skip this */
                    220:   if(data->req.upload_chunky &&
                    221:      data->state.trailers_state == TRAILERS_NONE) {
                    222:     /* if chunked Transfer-Encoding */
                    223:     buffersize -= (8 + 2 + 2);   /* 32bit hex + CRLF + CRLF */
                    224:     data->req.upload_fromhere += (8 + 2); /* 32bit hex + CRLF */
                    225:   }
                    226: 
                    227: #ifndef CURL_DISABLE_HTTP
                    228:   if(data->state.trailers_state == TRAILERS_SENDING) {
                    229:     /* if we're here then that means that we already sent the last empty chunk
                    230:        but we didn't send a final CR LF, so we sent 0 CR LF. We then start
                    231:        pulling trailing data until we have no more at which point we
                    232:        simply return to the previous point in the state machine as if
                    233:        nothing happened.
                    234:        */
                    235:     readfunc = Curl_trailers_read;
                    236:     extra_data = (void *)data;
                    237:   }
                    238:   else
                    239: #endif
                    240:   {
                    241:     readfunc = data->state.fread_func;
                    242:     extra_data = data->state.in;
                    243:   }
                    244: 
                    245:   Curl_set_in_callback(data, true);
                    246:   nread = readfunc(data->req.upload_fromhere, 1,
                    247:                    buffersize, extra_data);
                    248:   Curl_set_in_callback(data, false);
                    249: 
                    250:   if(nread == CURL_READFUNC_ABORT) {
                    251:     failf(data, "operation aborted by callback");
                    252:     *nreadp = 0;
                    253:     return CURLE_ABORTED_BY_CALLBACK;
                    254:   }
                    255:   if(nread == CURL_READFUNC_PAUSE) {
                    256:     struct SingleRequest *k = &data->req;
                    257: 
                    258:     if(conn->handler->flags & PROTOPT_NONETWORK) {
                    259:       /* protocols that work without network cannot be paused. This is
                    260:          actually only FILE:// just now, and it can't pause since the transfer
                    261:          isn't done using the "normal" procedure. */
                    262:       failf(data, "Read callback asked for PAUSE when not supported!");
                    263:       return CURLE_READ_ERROR;
                    264:     }
                    265: 
                    266:     /* CURL_READFUNC_PAUSE pauses read callbacks that feed socket writes */
                    267:     k->keepon |= KEEP_SEND_PAUSE; /* mark socket send as paused */
                    268:     if(data->req.upload_chunky) {
                    269:         /* Back out the preallocation done above */
                    270:       data->req.upload_fromhere -= (8 + 2);
                    271:     }
                    272:     *nreadp = 0;
                    273: 
                    274:     return CURLE_OK; /* nothing was read */
                    275:   }
                    276:   else if(nread > buffersize) {
                    277:     /* the read function returned a too large value */
                    278:     *nreadp = 0;
                    279:     failf(data, "read function returned funny value");
                    280:     return CURLE_READ_ERROR;
                    281:   }
                    282: 
                    283:   if(!data->req.forbidchunk && data->req.upload_chunky) {
                    284:     /* if chunked Transfer-Encoding
                    285:      *    build chunk:
                    286:      *
                    287:      *        <HEX SIZE> CRLF
                    288:      *        <DATA> CRLF
                    289:      */
                    290:     /* On non-ASCII platforms the <DATA> may or may not be
                    291:        translated based on set.prefer_ascii while the protocol
                    292:        portion must always be translated to the network encoding.
                    293:        To further complicate matters, line end conversion might be
                    294:        done later on, so we need to prevent CRLFs from becoming
                    295:        CRCRLFs if that's the case.  To do this we use bare LFs
                    296:        here, knowing they'll become CRLFs later on.
                    297:      */
                    298: 
                    299:     bool added_crlf = FALSE;
                    300:     int hexlen = 0;
                    301:     const char *endofline_native;
                    302:     const char *endofline_network;
                    303: 
                    304:     if(
                    305: #ifdef CURL_DO_LINEEND_CONV
                    306:        (data->set.prefer_ascii) ||
                    307: #endif
                    308:        (data->set.crlf)) {
                    309:       /* \n will become \r\n later on */
                    310:       endofline_native  = "\n";
                    311:       endofline_network = "\x0a";
                    312:     }
                    313:     else {
                    314:       endofline_native  = "\r\n";
                    315:       endofline_network = "\x0d\x0a";
                    316:     }
                    317: 
                    318:     /* if we're not handling trailing data, proceed as usual */
                    319:     if(data->state.trailers_state != TRAILERS_SENDING) {
                    320:       char hexbuffer[11] = "";
                    321:       hexlen = msnprintf(hexbuffer, sizeof(hexbuffer),
                    322:                          "%zx%s", nread, endofline_native);
                    323: 
                    324:       /* move buffer pointer */
                    325:       data->req.upload_fromhere -= hexlen;
                    326:       nread += hexlen;
                    327: 
                    328:       /* copy the prefix to the buffer, leaving out the NUL */
                    329:       memcpy(data->req.upload_fromhere, hexbuffer, hexlen);
                    330: 
                    331:       /* always append ASCII CRLF to the data unless
                    332:          we have a valid trailer callback */
                    333: #ifndef CURL_DISABLE_HTTP
                    334:       if((nread-hexlen) == 0 &&
                    335:           data->set.trailer_callback != NULL &&
                    336:           data->state.trailers_state == TRAILERS_NONE) {
                    337:         data->state.trailers_state = TRAILERS_INITIALIZED;
                    338:       }
                    339:       else
                    340: #endif
                    341:       {
                    342:         memcpy(data->req.upload_fromhere + nread,
                    343:                endofline_network,
                    344:                strlen(endofline_network));
                    345:         added_crlf = TRUE;
                    346:       }
                    347:     }
                    348: 
                    349: #ifdef CURL_DOES_CONVERSIONS
                    350:     {
                    351:       CURLcode result;
                    352:       size_t length;
                    353:       if(data->set.prefer_ascii)
                    354:         /* translate the protocol and data */
                    355:         length = nread;
                    356:       else
                    357:         /* just translate the protocol portion */
                    358:         length = hexlen;
                    359:       if(length) {
                    360:         result = Curl_convert_to_network(data, data->req.upload_fromhere,
                    361:                                          length);
                    362:         /* Curl_convert_to_network calls failf if unsuccessful */
                    363:         if(result)
                    364:           return result;
                    365:       }
                    366:     }
                    367: #endif /* CURL_DOES_CONVERSIONS */
                    368: 
                    369: #ifndef CURL_DISABLE_HTTP
                    370:     if(data->state.trailers_state == TRAILERS_SENDING &&
                    371:        !Curl_trailers_left(data)) {
                    372:       Curl_add_buffer_free(&data->state.trailers_buf);
                    373:       data->state.trailers_state = TRAILERS_DONE;
                    374:       data->set.trailer_data = NULL;
                    375:       data->set.trailer_callback = NULL;
                    376:       /* mark the transfer as done */
                    377:       data->req.upload_done = TRUE;
                    378:       infof(data, "Signaling end of chunked upload after trailers.\n");
                    379:     }
                    380:     else
                    381: #endif
                    382:       if((nread - hexlen) == 0 &&
                    383:          data->state.trailers_state != TRAILERS_INITIALIZED) {
                    384:         /* mark this as done once this chunk is transferred */
                    385:         data->req.upload_done = TRUE;
                    386:         infof(data,
                    387:               "Signaling end of chunked upload via terminating chunk.\n");
                    388:       }
                    389: 
                    390:     if(added_crlf)
                    391:       nread += strlen(endofline_network); /* for the added end of line */
                    392:   }
                    393: #ifdef CURL_DOES_CONVERSIONS
                    394:   else if((data->set.prefer_ascii) && (!sending_http_headers)) {
                    395:     CURLcode result;
                    396:     result = Curl_convert_to_network(data, data->req.upload_fromhere, nread);
                    397:     /* Curl_convert_to_network calls failf if unsuccessful */
                    398:     if(result)
                    399:       return result;
                    400:   }
                    401: #endif /* CURL_DOES_CONVERSIONS */
                    402: 
                    403:   *nreadp = nread;
                    404: 
                    405:   return CURLE_OK;
                    406: }
                    407: 
                    408: 
                    409: /*
                    410:  * Curl_readrewind() rewinds the read stream. This is typically used for HTTP
                    411:  * POST/PUT with multi-pass authentication when a sending was denied and a
                    412:  * resend is necessary.
                    413:  */
                    414: CURLcode Curl_readrewind(struct connectdata *conn)
                    415: {
                    416:   struct Curl_easy *data = conn->data;
                    417:   curl_mimepart *mimepart = &data->set.mimepost;
                    418: 
                    419:   conn->bits.rewindaftersend = FALSE; /* we rewind now */
                    420: 
                    421:   /* explicitly switch off sending data on this connection now since we are
                    422:      about to restart a new transfer and thus we want to avoid inadvertently
                    423:      sending more data on the existing connection until the next transfer
                    424:      starts */
                    425:   data->req.keepon &= ~KEEP_SEND;
                    426: 
                    427:   /* We have sent away data. If not using CURLOPT_POSTFIELDS or
                    428:      CURLOPT_HTTPPOST, call app to rewind
                    429:   */
                    430:   if(conn->handler->protocol & PROTO_FAMILY_HTTP) {
                    431:     struct HTTP *http = data->req.protop;
                    432: 
                    433:     if(http->sendit)
                    434:       mimepart = http->sendit;
                    435:   }
                    436:   if(data->set.postfields)
                    437:     ; /* do nothing */
                    438:   else if(data->set.httpreq == HTTPREQ_POST_MIME ||
                    439:           data->set.httpreq == HTTPREQ_POST_FORM) {
                    440:     if(Curl_mime_rewind(mimepart)) {
                    441:       failf(data, "Cannot rewind mime/post data");
                    442:       return CURLE_SEND_FAIL_REWIND;
                    443:     }
                    444:   }
                    445:   else {
                    446:     if(data->set.seek_func) {
                    447:       int err;
                    448: 
                    449:       Curl_set_in_callback(data, true);
                    450:       err = (data->set.seek_func)(data->set.seek_client, 0, SEEK_SET);
                    451:       Curl_set_in_callback(data, false);
                    452:       if(err) {
                    453:         failf(data, "seek callback returned error %d", (int)err);
                    454:         return CURLE_SEND_FAIL_REWIND;
                    455:       }
                    456:     }
                    457:     else if(data->set.ioctl_func) {
                    458:       curlioerr err;
                    459: 
                    460:       Curl_set_in_callback(data, true);
                    461:       err = (data->set.ioctl_func)(data, CURLIOCMD_RESTARTREAD,
                    462:                                    data->set.ioctl_client);
                    463:       Curl_set_in_callback(data, false);
                    464:       infof(data, "the ioctl callback returned %d\n", (int)err);
                    465: 
                    466:       if(err) {
                    467:         failf(data, "ioctl callback returned error %d", (int)err);
                    468:         return CURLE_SEND_FAIL_REWIND;
                    469:       }
                    470:     }
                    471:     else {
                    472:       /* If no CURLOPT_READFUNCTION is used, we know that we operate on a
                    473:          given FILE * stream and we can actually attempt to rewind that
                    474:          ourselves with fseek() */
                    475:       if(data->state.fread_func == (curl_read_callback)fread) {
                    476:         if(-1 != fseek(data->state.in, 0, SEEK_SET))
                    477:           /* successful rewind */
                    478:           return CURLE_OK;
                    479:       }
                    480: 
                    481:       /* no callback set or failure above, makes us fail at once */
                    482:       failf(data, "necessary data rewind wasn't possible");
                    483:       return CURLE_SEND_FAIL_REWIND;
                    484:     }
                    485:   }
                    486:   return CURLE_OK;
                    487: }
                    488: 
                    489: static int data_pending(const struct Curl_easy *data)
                    490: {
                    491:   struct connectdata *conn = data->conn;
                    492:   /* in the case of libssh2, we can never be really sure that we have emptied
                    493:      its internal buffers so we MUST always try until we get EAGAIN back */
                    494:   return conn->handler->protocol&(CURLPROTO_SCP|CURLPROTO_SFTP) ||
                    495: #if defined(USE_NGHTTP2)
                    496:     Curl_ssl_data_pending(conn, FIRSTSOCKET) ||
                    497:     /* For HTTP/2, we may read up everything including response body
                    498:        with header fields in Curl_http_readwrite_headers. If no
                    499:        content-length is provided, curl waits for the connection
                    500:        close, which we emulate it using conn->proto.httpc.closed =
                    501:        TRUE. The thing is if we read everything, then http2_recv won't
                    502:        be called and we cannot signal the HTTP/2 stream has closed. As
                    503:        a workaround, we return nonzero here to call http2_recv. */
                    504:     ((conn->handler->protocol&PROTO_FAMILY_HTTP) && conn->httpversion >= 20);
                    505: #elif defined(ENABLE_QUIC)
                    506:     Curl_ssl_data_pending(conn, FIRSTSOCKET) || Curl_quic_data_pending(data);
                    507: #else
                    508:     Curl_ssl_data_pending(conn, FIRSTSOCKET);
                    509: #endif
                    510: }
                    511: 
                    512: /*
                    513:  * Check to see if CURLOPT_TIMECONDITION was met by comparing the time of the
                    514:  * remote document with the time provided by CURLOPT_TIMEVAL
                    515:  */
                    516: bool Curl_meets_timecondition(struct Curl_easy *data, time_t timeofdoc)
                    517: {
                    518:   if((timeofdoc == 0) || (data->set.timevalue == 0))
                    519:     return TRUE;
                    520: 
                    521:   switch(data->set.timecondition) {
                    522:   case CURL_TIMECOND_IFMODSINCE:
                    523:   default:
                    524:     if(timeofdoc <= data->set.timevalue) {
                    525:       infof(data,
                    526:             "The requested document is not new enough\n");
                    527:       data->info.timecond = TRUE;
                    528:       return FALSE;
                    529:     }
                    530:     break;
                    531:   case CURL_TIMECOND_IFUNMODSINCE:
                    532:     if(timeofdoc >= data->set.timevalue) {
                    533:       infof(data,
                    534:             "The requested document is not old enough\n");
                    535:       data->info.timecond = TRUE;
                    536:       return FALSE;
                    537:     }
                    538:     break;
                    539:   }
                    540: 
                    541:   return TRUE;
                    542: }
                    543: 
                    544: /*
                    545:  * Go ahead and do a read if we have a readable socket or if
                    546:  * the stream was rewound (in which case we have data in a
                    547:  * buffer)
                    548:  *
                    549:  * return '*comeback' TRUE if we didn't properly drain the socket so this
                    550:  * function should get called again without select() or similar in between!
                    551:  */
                    552: static CURLcode readwrite_data(struct Curl_easy *data,
                    553:                                struct connectdata *conn,
                    554:                                struct SingleRequest *k,
                    555:                                int *didwhat, bool *done,
                    556:                                bool *comeback)
                    557: {
                    558:   CURLcode result = CURLE_OK;
                    559:   ssize_t nread; /* number of bytes read */
                    560:   size_t excess = 0; /* excess bytes read */
                    561:   bool readmore = FALSE; /* used by RTP to signal for more data */
                    562:   int maxloops = 100;
                    563: 
                    564:   *done = FALSE;
                    565:   *comeback = FALSE;
                    566: 
                    567:   /* This is where we loop until we have read everything there is to
                    568:      read or we get a CURLE_AGAIN */
                    569:   do {
                    570:     bool is_empty_data = FALSE;
                    571:     size_t buffersize = data->set.buffer_size;
                    572:     size_t bytestoread = buffersize;
                    573: #ifdef USE_NGHTTP2
                    574:     bool is_http2 = ((conn->handler->protocol & PROTO_FAMILY_HTTP) &&
                    575:                      (conn->httpversion == 20));
                    576: #endif
                    577: 
                    578:     if(
                    579: #ifdef USE_NGHTTP2
                    580:        /* For HTTP/2, read data without caring about the content
                    581:           length. This is safe because body in HTTP/2 is always
                    582:           segmented thanks to its framing layer. Meanwhile, we have to
                    583:           call Curl_read to ensure that http2_handle_stream_close is
                    584:           called when we read all incoming bytes for a particular
                    585:           stream. */
                    586:        !is_http2 &&
                    587: #endif
                    588:        k->size != -1 && !k->header) {
                    589:       /* make sure we don't read too much */
                    590:       curl_off_t totalleft = k->size - k->bytecount;
                    591:       if(totalleft < (curl_off_t)bytestoread)
                    592:         bytestoread = (size_t)totalleft;
                    593:     }
                    594: 
                    595:     if(bytestoread) {
                    596:       /* receive data from the network! */
                    597:       result = Curl_read(conn, conn->sockfd, k->buf, bytestoread, &nread);
                    598: 
                    599:       /* read would've blocked */
                    600:       if(CURLE_AGAIN == result)
                    601:         break; /* get out of loop */
                    602: 
                    603:       if(result>0)
                    604:         return result;
                    605:     }
                    606:     else {
                    607:       /* read nothing but since we wanted nothing we consider this an OK
                    608:          situation to proceed from */
                    609:       DEBUGF(infof(data, "readwrite_data: we're done!\n"));
                    610:       nread = 0;
                    611:     }
                    612: 
                    613:     if(!k->bytecount) {
                    614:       Curl_pgrsTime(data, TIMER_STARTTRANSFER);
                    615:       if(k->exp100 > EXP100_SEND_DATA)
                    616:         /* set time stamp to compare with when waiting for the 100 */
                    617:         k->start100 = Curl_now();
                    618:     }
                    619: 
                    620:     *didwhat |= KEEP_RECV;
                    621:     /* indicates data of zero size, i.e. empty file */
                    622:     is_empty_data = ((nread == 0) && (k->bodywrites == 0)) ? TRUE : FALSE;
                    623: 
                    624:     /* NUL terminate, allowing string ops to be used */
                    625:     if(0 < nread || is_empty_data) {
                    626:       k->buf[nread] = 0;
                    627:     }
                    628:     else {
                    629:       /* if we receive 0 or less here, either the http2 stream is closed or the
                    630:          server closed the connection and we bail out from this! */
                    631: #ifdef USE_NGHTTP2
                    632:       if(is_http2 && !nread)
                    633:         DEBUGF(infof(data, "nread == 0, stream closed, bailing\n"));
                    634:       else
                    635: #endif
                    636:         DEBUGF(infof(data, "nread <= 0, server closed connection, bailing\n"));
                    637:       k->keepon &= ~KEEP_RECV;
                    638:       break;
                    639:     }
                    640: 
                    641:     /* Default buffer to use when we write the buffer, it may be changed
                    642:        in the flow below before the actual storing is done. */
                    643:     k->str = k->buf;
                    644: 
                    645:     if(conn->handler->readwrite) {
                    646:       result = conn->handler->readwrite(data, conn, &nread, &readmore);
                    647:       if(result)
                    648:         return result;
                    649:       if(readmore)
                    650:         break;
                    651:     }
                    652: 
                    653: #ifndef CURL_DISABLE_HTTP
                    654:     /* Since this is a two-state thing, we check if we are parsing
                    655:        headers at the moment or not. */
                    656:     if(k->header) {
                    657:       /* we are in parse-the-header-mode */
                    658:       bool stop_reading = FALSE;
                    659:       result = Curl_http_readwrite_headers(data, conn, &nread, &stop_reading);
                    660:       if(result)
                    661:         return result;
                    662: 
                    663:       if(conn->handler->readwrite &&
                    664:          (k->maxdownload <= 0 && nread > 0)) {
                    665:         result = conn->handler->readwrite(data, conn, &nread, &readmore);
                    666:         if(result)
                    667:           return result;
                    668:         if(readmore)
                    669:           break;
                    670:       }
                    671: 
                    672:       if(stop_reading) {
                    673:         /* We've stopped dealing with input, get out of the do-while loop */
                    674: 
                    675:         if(nread > 0) {
                    676:           infof(data,
                    677:                 "Excess found:"
                    678:                 " excess = %zd"
                    679:                 " url = %s (zero-length body)\n",
                    680:                 nread, data->state.up.path);
                    681:         }
                    682: 
                    683:         break;
                    684:       }
                    685:     }
                    686: #endif /* CURL_DISABLE_HTTP */
                    687: 
                    688: 
                    689:     /* This is not an 'else if' since it may be a rest from the header
                    690:        parsing, where the beginning of the buffer is headers and the end
                    691:        is non-headers. */
                    692:     if(k->str && !k->header && (nread > 0 || is_empty_data)) {
                    693: 
                    694:       if(data->set.opt_no_body) {
                    695:         /* data arrives although we want none, bail out */
                    696:         streamclose(conn, "ignoring body");
                    697:         *done = TRUE;
                    698:         return CURLE_WEIRD_SERVER_REPLY;
                    699:       }
                    700: 
                    701: #ifndef CURL_DISABLE_HTTP
                    702:       if(0 == k->bodywrites && !is_empty_data) {
                    703:         /* These checks are only made the first time we are about to
                    704:            write a piece of the body */
                    705:         if(conn->handler->protocol&(PROTO_FAMILY_HTTP|CURLPROTO_RTSP)) {
                    706:           /* HTTP-only checks */
                    707: 
                    708:           if(data->req.newurl) {
                    709:             if(conn->bits.close) {
                    710:               /* Abort after the headers if "follow Location" is set
                    711:                  and we're set to close anyway. */
                    712:               k->keepon &= ~KEEP_RECV;
                    713:               *done = TRUE;
                    714:               return CURLE_OK;
                    715:             }
                    716:             /* We have a new url to load, but since we want to be able
                    717:                to re-use this connection properly, we read the full
                    718:                response in "ignore more" */
                    719:             k->ignorebody = TRUE;
                    720:             infof(data, "Ignoring the response-body\n");
                    721:           }
                    722:           if(data->state.resume_from && !k->content_range &&
                    723:              (data->set.httpreq == HTTPREQ_GET) &&
                    724:              !k->ignorebody) {
                    725: 
                    726:             if(k->size == data->state.resume_from) {
                    727:               /* The resume point is at the end of file, consider this fine
                    728:                  even if it doesn't allow resume from here. */
                    729:               infof(data, "The entire document is already downloaded");
                    730:               connclose(conn, "already downloaded");
                    731:               /* Abort download */
                    732:               k->keepon &= ~KEEP_RECV;
                    733:               *done = TRUE;
                    734:               return CURLE_OK;
                    735:             }
                    736: 
                    737:             /* we wanted to resume a download, although the server doesn't
                    738:              * seem to support this and we did this with a GET (if it
                    739:              * wasn't a GET we did a POST or PUT resume) */
                    740:             failf(data, "HTTP server doesn't seem to support "
                    741:                   "byte ranges. Cannot resume.");
                    742:             return CURLE_RANGE_ERROR;
                    743:           }
                    744: 
                    745:           if(data->set.timecondition && !data->state.range) {
                    746:             /* A time condition has been set AND no ranges have been
                    747:                requested. This seems to be what chapter 13.3.4 of
                    748:                RFC 2616 defines to be the correct action for a
                    749:                HTTP/1.1 client */
                    750: 
                    751:             if(!Curl_meets_timecondition(data, k->timeofdoc)) {
                    752:               *done = TRUE;
                    753:               /* We're simulating a http 304 from server so we return
                    754:                  what should have been returned from the server */
                    755:               data->info.httpcode = 304;
                    756:               infof(data, "Simulate a HTTP 304 response!\n");
                    757:               /* we abort the transfer before it is completed == we ruin the
                    758:                  re-use ability. Close the connection */
                    759:               connclose(conn, "Simulated 304 handling");
                    760:               return CURLE_OK;
                    761:             }
                    762:           } /* we have a time condition */
                    763: 
                    764:         } /* this is HTTP or RTSP */
                    765:       } /* this is the first time we write a body part */
                    766: #endif /* CURL_DISABLE_HTTP */
                    767: 
                    768:       k->bodywrites++;
                    769: 
                    770:       /* pass data to the debug function before it gets "dechunked" */
                    771:       if(data->set.verbose) {
                    772:         if(k->badheader) {
                    773:           Curl_debug(data, CURLINFO_DATA_IN, data->state.headerbuff,
                    774:                      (size_t)k->hbuflen);
                    775:           if(k->badheader == HEADER_PARTHEADER)
                    776:             Curl_debug(data, CURLINFO_DATA_IN,
                    777:                        k->str, (size_t)nread);
                    778:         }
                    779:         else
                    780:           Curl_debug(data, CURLINFO_DATA_IN,
                    781:                      k->str, (size_t)nread);
                    782:       }
                    783: 
                    784: #ifndef CURL_DISABLE_HTTP
                    785:       if(k->chunk) {
                    786:         /*
                    787:          * Here comes a chunked transfer flying and we need to decode this
                    788:          * properly.  While the name says read, this function both reads
                    789:          * and writes away the data. The returned 'nread' holds the number
                    790:          * of actual data it wrote to the client.
                    791:          */
                    792:         CURLcode extra;
                    793:         CHUNKcode res =
                    794:           Curl_httpchunk_read(conn, k->str, nread, &nread, &extra);
                    795: 
                    796:         if(CHUNKE_OK < res) {
                    797:           if(CHUNKE_PASSTHRU_ERROR == res) {
                    798:             failf(data, "Failed reading the chunked-encoded stream");
                    799:             return extra;
                    800:           }
                    801:           failf(data, "%s in chunked-encoding", Curl_chunked_strerror(res));
                    802:           return CURLE_RECV_ERROR;
                    803:         }
                    804:         if(CHUNKE_STOP == res) {
                    805:           size_t dataleft;
                    806:           /* we're done reading chunks! */
                    807:           k->keepon &= ~KEEP_RECV; /* read no more */
                    808: 
                    809:           /* There are now possibly N number of bytes at the end of the
                    810:              str buffer that weren't written to the client.
                    811:              Push it back to be read on the next pass. */
                    812: 
                    813:           dataleft = conn->chunk.dataleft;
                    814:           if(dataleft != 0) {
                    815:             infof(conn->data, "Leftovers after chunking: %zu bytes\n",
                    816:                   dataleft);
                    817:           }
                    818:         }
                    819:         /* If it returned OK, we just keep going */
                    820:       }
                    821: #endif   /* CURL_DISABLE_HTTP */
                    822: 
                    823:       /* Account for body content stored in the header buffer */
                    824:       if((k->badheader == HEADER_PARTHEADER) && !k->ignorebody) {
                    825:         DEBUGF(infof(data, "Increasing bytecount by %zu from hbuflen\n",
                    826:                      k->hbuflen));
                    827:         k->bytecount += k->hbuflen;
                    828:       }
                    829: 
                    830:       if((-1 != k->maxdownload) &&
                    831:          (k->bytecount + nread >= k->maxdownload)) {
                    832: 
                    833:         excess = (size_t)(k->bytecount + nread - k->maxdownload);
                    834:         if(excess > 0 && !k->ignorebody) {
                    835:           infof(data,
                    836:                 "Excess found in a read:"
                    837:                 " excess = %zu"
                    838:                 ", size = %" CURL_FORMAT_CURL_OFF_T
                    839:                 ", maxdownload = %" CURL_FORMAT_CURL_OFF_T
                    840:                 ", bytecount = %" CURL_FORMAT_CURL_OFF_T "\n",
                    841:                 excess, k->size, k->maxdownload, k->bytecount);
                    842:         }
                    843: 
                    844:         nread = (ssize_t) (k->maxdownload - k->bytecount);
                    845:         if(nread < 0) /* this should be unusual */
                    846:           nread = 0;
                    847: 
                    848:         k->keepon &= ~KEEP_RECV; /* we're done reading */
                    849:       }
                    850: 
                    851:       k->bytecount += nread;
                    852: 
                    853:       Curl_pgrsSetDownloadCounter(data, k->bytecount);
                    854: 
                    855:       if(!k->chunk && (nread || k->badheader || is_empty_data)) {
                    856:         /* If this is chunky transfer, it was already written */
                    857: 
                    858:         if(k->badheader && !k->ignorebody) {
                    859:           /* we parsed a piece of data wrongly assuming it was a header
                    860:              and now we output it as body instead */
                    861: 
                    862:           /* Don't let excess data pollute body writes */
                    863:           if(k->maxdownload == -1 || (curl_off_t)k->hbuflen <= k->maxdownload)
                    864:             result = Curl_client_write(conn, CLIENTWRITE_BODY,
                    865:                                        data->state.headerbuff,
                    866:                                        k->hbuflen);
                    867:           else
                    868:             result = Curl_client_write(conn, CLIENTWRITE_BODY,
                    869:                                        data->state.headerbuff,
                    870:                                        (size_t)k->maxdownload);
                    871: 
                    872:           if(result)
                    873:             return result;
                    874:         }
                    875:         if(k->badheader < HEADER_ALLBAD) {
                    876:           /* This switch handles various content encodings. If there's an
                    877:              error here, be sure to check over the almost identical code
                    878:              in http_chunks.c.
                    879:              Make sure that ALL_CONTENT_ENCODINGS contains all the
                    880:              encodings handled here. */
                    881:           if(conn->data->set.http_ce_skip || !k->writer_stack) {
                    882:             if(!k->ignorebody) {
                    883: #ifndef CURL_DISABLE_POP3
                    884:               if(conn->handler->protocol & PROTO_FAMILY_POP3)
                    885:                 result = Curl_pop3_write(conn, k->str, nread);
                    886:               else
                    887: #endif /* CURL_DISABLE_POP3 */
                    888:                 result = Curl_client_write(conn, CLIENTWRITE_BODY, k->str,
                    889:                                            nread);
                    890:             }
                    891:           }
                    892:           else if(!k->ignorebody)
                    893:             result = Curl_unencode_write(conn, k->writer_stack, k->str, nread);
                    894:         }
                    895:         k->badheader = HEADER_NORMAL; /* taken care of now */
                    896: 
                    897:         if(result)
                    898:           return result;
                    899:       }
                    900: 
                    901:     } /* if(!header and data to read) */
                    902: 
                    903:     if(conn->handler->readwrite && excess) {
                    904:       /* Parse the excess data */
                    905:       k->str += nread;
                    906: 
                    907:       if(&k->str[excess] > &k->buf[data->set.buffer_size]) {
                    908:         /* the excess amount was too excessive(!), make sure
                    909:            it doesn't read out of buffer */
                    910:         excess = &k->buf[data->set.buffer_size] - k->str;
                    911:       }
                    912:       nread = (ssize_t)excess;
                    913: 
                    914:       result = conn->handler->readwrite(data, conn, &nread, &readmore);
                    915:       if(result)
                    916:         return result;
                    917: 
                    918:       if(readmore)
                    919:         k->keepon |= KEEP_RECV; /* we're not done reading */
                    920:       break;
                    921:     }
                    922: 
                    923:     if(is_empty_data) {
                    924:       /* if we received nothing, the server closed the connection and we
                    925:          are done */
                    926:       k->keepon &= ~KEEP_RECV;
                    927:     }
                    928: 
                    929:     if(k->keepon & KEEP_RECV_PAUSE) {
                    930:       /* this is a paused transfer */
                    931:       break;
                    932:     }
                    933: 
                    934:   } while(data_pending(data) && maxloops--);
                    935: 
                    936:   if(maxloops <= 0) {
                    937:     /* we mark it as read-again-please */
                    938:     conn->cselect_bits = CURL_CSELECT_IN;
                    939:     *comeback = TRUE;
                    940:   }
                    941: 
                    942:   if(((k->keepon & (KEEP_RECV|KEEP_SEND)) == KEEP_SEND) &&
                    943:      conn->bits.close) {
                    944:     /* When we've read the entire thing and the close bit is set, the server
                    945:        may now close the connection. If there's now any kind of sending going
                    946:        on from our side, we need to stop that immediately. */
                    947:     infof(data, "we are done reading and this is set to close, stop send\n");
                    948:     k->keepon &= ~KEEP_SEND; /* no writing anymore either */
                    949:   }
                    950: 
                    951:   return CURLE_OK;
                    952: }
                    953: 
                    954: CURLcode Curl_done_sending(struct connectdata *conn,
                    955:                            struct SingleRequest *k)
                    956: {
                    957:   k->keepon &= ~KEEP_SEND; /* we're done writing */
                    958: 
                    959:   /* These functions should be moved into the handler struct! */
                    960:   Curl_http2_done_sending(conn);
                    961:   Curl_quic_done_sending(conn);
                    962: 
                    963:   if(conn->bits.rewindaftersend) {
                    964:     CURLcode result = Curl_readrewind(conn);
                    965:     if(result)
                    966:       return result;
                    967:   }
                    968:   return CURLE_OK;
                    969: }
                    970: 
                    971: #if defined(WIN32) && !defined(USE_LWIPSOCK)
                    972: #ifndef SIO_IDEAL_SEND_BACKLOG_QUERY
                    973: #define SIO_IDEAL_SEND_BACKLOG_QUERY 0x4004747B
                    974: #endif
                    975: 
                    976: static void win_update_buffer_size(curl_socket_t sockfd)
                    977: {
                    978:   int result;
                    979:   ULONG ideal;
                    980:   DWORD ideallen;
                    981:   result = WSAIoctl(sockfd, SIO_IDEAL_SEND_BACKLOG_QUERY, 0, 0,
                    982:                     &ideal, sizeof(ideal), &ideallen, 0, 0);
                    983:   if(result == 0) {
                    984:     setsockopt(sockfd, SOL_SOCKET, SO_SNDBUF,
                    985:                (const char *)&ideal, sizeof(ideal));
                    986:   }
                    987: }
                    988: #else
                    989: #define win_update_buffer_size(x)
                    990: #endif
                    991: 
                    992: /*
                    993:  * Send data to upload to the server, when the socket is writable.
                    994:  */
                    995: static CURLcode readwrite_upload(struct Curl_easy *data,
                    996:                                  struct connectdata *conn,
                    997:                                  int *didwhat)
                    998: {
                    999:   ssize_t i, si;
                   1000:   ssize_t bytes_written;
                   1001:   CURLcode result;
                   1002:   ssize_t nread; /* number of bytes read */
                   1003:   bool sending_http_headers = FALSE;
                   1004:   struct SingleRequest *k = &data->req;
                   1005: 
                   1006:   if((k->bytecount == 0) && (k->writebytecount == 0))
                   1007:     Curl_pgrsTime(data, TIMER_STARTTRANSFER);
                   1008: 
                   1009:   *didwhat |= KEEP_SEND;
                   1010: 
                   1011:   do {
                   1012:     /* only read more data if there's no upload data already
                   1013:        present in the upload buffer */
                   1014:     if(0 == k->upload_present) {
                   1015:       result = Curl_get_upload_buffer(data);
                   1016:       if(result)
                   1017:         return result;
                   1018:       /* init the "upload from here" pointer */
                   1019:       k->upload_fromhere = data->state.ulbuf;
                   1020: 
                   1021:       if(!k->upload_done) {
                   1022:         /* HTTP pollution, this should be written nicer to become more
                   1023:            protocol agnostic. */
                   1024:         size_t fillcount;
                   1025:         struct HTTP *http = k->protop;
                   1026: 
                   1027:         if((k->exp100 == EXP100_SENDING_REQUEST) &&
                   1028:            (http->sending == HTTPSEND_BODY)) {
                   1029:           /* If this call is to send body data, we must take some action:
                   1030:              We have sent off the full HTTP 1.1 request, and we shall now
                   1031:              go into the Expect: 100 state and await such a header */
                   1032:           k->exp100 = EXP100_AWAITING_CONTINUE; /* wait for the header */
                   1033:           k->keepon &= ~KEEP_SEND;         /* disable writing */
                   1034:           k->start100 = Curl_now();       /* timeout count starts now */
                   1035:           *didwhat &= ~KEEP_SEND;  /* we didn't write anything actually */
                   1036:           /* set a timeout for the multi interface */
                   1037:           Curl_expire(data, data->set.expect_100_timeout, EXPIRE_100_TIMEOUT);
                   1038:           break;
                   1039:         }
                   1040: 
                   1041:         if(conn->handler->protocol&(PROTO_FAMILY_HTTP|CURLPROTO_RTSP)) {
                   1042:           if(http->sending == HTTPSEND_REQUEST)
                   1043:             /* We're sending the HTTP request headers, not the data.
                   1044:                Remember that so we don't change the line endings. */
                   1045:             sending_http_headers = TRUE;
                   1046:           else
                   1047:             sending_http_headers = FALSE;
                   1048:         }
                   1049: 
                   1050:         result = Curl_fillreadbuffer(conn, data->set.upload_buffer_size,
                   1051:                                      &fillcount);
                   1052:         if(result)
                   1053:           return result;
                   1054: 
                   1055:         nread = fillcount;
                   1056:       }
                   1057:       else
                   1058:         nread = 0; /* we're done uploading/reading */
                   1059: 
                   1060:       if(!nread && (k->keepon & KEEP_SEND_PAUSE)) {
                   1061:         /* this is a paused transfer */
                   1062:         break;
                   1063:       }
                   1064:       if(nread <= 0) {
                   1065:         result = Curl_done_sending(conn, k);
                   1066:         if(result)
                   1067:           return result;
                   1068:         break;
                   1069:       }
                   1070: 
                   1071:       /* store number of bytes available for upload */
                   1072:       k->upload_present = nread;
                   1073: 
                   1074:       /* convert LF to CRLF if so asked */
                   1075:       if((!sending_http_headers) && (
                   1076: #ifdef CURL_DO_LINEEND_CONV
                   1077:          /* always convert if we're FTPing in ASCII mode */
                   1078:          (data->set.prefer_ascii) ||
                   1079: #endif
                   1080:          (data->set.crlf))) {
                   1081:         /* Do we need to allocate a scratch buffer? */
                   1082:         if(!data->state.scratch) {
                   1083:           data->state.scratch = malloc(2 * data->set.upload_buffer_size);
                   1084:           if(!data->state.scratch) {
                   1085:             failf(data, "Failed to alloc scratch buffer!");
                   1086: 
                   1087:             return CURLE_OUT_OF_MEMORY;
                   1088:           }
                   1089:         }
                   1090: 
                   1091:         /*
                   1092:          * ASCII/EBCDIC Note: This is presumably a text (not binary)
                   1093:          * transfer so the data should already be in ASCII.
                   1094:          * That means the hex values for ASCII CR (0x0d) & LF (0x0a)
                   1095:          * must be used instead of the escape sequences \r & \n.
                   1096:          */
                   1097:         for(i = 0, si = 0; i < nread; i++, si++) {
                   1098:           if(k->upload_fromhere[i] == 0x0a) {
                   1099:             data->state.scratch[si++] = 0x0d;
                   1100:             data->state.scratch[si] = 0x0a;
                   1101:             if(!data->set.crlf) {
                   1102:               /* we're here only because FTP is in ASCII mode...
                   1103:                  bump infilesize for the LF we just added */
                   1104:               if(data->state.infilesize != -1)
                   1105:                 data->state.infilesize++;
                   1106:             }
                   1107:           }
                   1108:           else
                   1109:             data->state.scratch[si] = k->upload_fromhere[i];
                   1110:         }
                   1111: 
                   1112:         if(si != nread) {
                   1113:           /* only perform the special operation if we really did replace
                   1114:              anything */
                   1115:           nread = si;
                   1116: 
                   1117:           /* upload from the new (replaced) buffer instead */
                   1118:           k->upload_fromhere = data->state.scratch;
                   1119: 
                   1120:           /* set the new amount too */
                   1121:           k->upload_present = nread;
                   1122:         }
                   1123:       }
                   1124: 
                   1125: #ifndef CURL_DISABLE_SMTP
                   1126:       if(conn->handler->protocol & PROTO_FAMILY_SMTP) {
                   1127:         result = Curl_smtp_escape_eob(conn, nread);
                   1128:         if(result)
                   1129:           return result;
                   1130:       }
                   1131: #endif /* CURL_DISABLE_SMTP */
                   1132:     } /* if 0 == k->upload_present */
                   1133:     else {
                   1134:       /* We have a partial buffer left from a previous "round". Use
                   1135:          that instead of reading more data */
                   1136:     }
                   1137: 
                   1138:     /* write to socket (send away data) */
                   1139:     result = Curl_write(conn,
                   1140:                         conn->writesockfd,  /* socket to send to */
                   1141:                         k->upload_fromhere, /* buffer pointer */
                   1142:                         k->upload_present,  /* buffer size */
                   1143:                         &bytes_written);    /* actually sent */
                   1144:     if(result)
                   1145:       return result;
                   1146: 
                   1147:     win_update_buffer_size(conn->writesockfd);
                   1148: 
                   1149:     if(data->set.verbose)
                   1150:       /* show the data before we change the pointer upload_fromhere */
                   1151:       Curl_debug(data, CURLINFO_DATA_OUT, k->upload_fromhere,
                   1152:                  (size_t)bytes_written);
                   1153: 
                   1154:     k->writebytecount += bytes_written;
                   1155:     Curl_pgrsSetUploadCounter(data, k->writebytecount);
                   1156: 
                   1157:     if((!k->upload_chunky || k->forbidchunk) &&
                   1158:        (k->writebytecount == data->state.infilesize)) {
                   1159:       /* we have sent all data we were supposed to */
                   1160:       k->upload_done = TRUE;
                   1161:       infof(data, "We are completely uploaded and fine\n");
                   1162:     }
                   1163: 
                   1164:     if(k->upload_present != bytes_written) {
                   1165:       /* we only wrote a part of the buffer (if anything), deal with it! */
                   1166: 
                   1167:       /* store the amount of bytes left in the buffer to write */
                   1168:       k->upload_present -= bytes_written;
                   1169: 
                   1170:       /* advance the pointer where to find the buffer when the next send
                   1171:          is to happen */
                   1172:       k->upload_fromhere += bytes_written;
                   1173:     }
                   1174:     else {
                   1175:       /* we've uploaded that buffer now */
                   1176:       result = Curl_get_upload_buffer(data);
                   1177:       if(result)
                   1178:         return result;
                   1179:       k->upload_fromhere = data->state.ulbuf;
                   1180:       k->upload_present = 0; /* no more bytes left */
                   1181: 
                   1182:       if(k->upload_done) {
                   1183:         result = Curl_done_sending(conn, k);
                   1184:         if(result)
                   1185:           return result;
                   1186:       }
                   1187:     }
                   1188: 
                   1189: 
                   1190:   } while(0); /* just to break out from! */
                   1191: 
                   1192:   return CURLE_OK;
                   1193: }
                   1194: 
                   1195: /*
                   1196:  * Curl_readwrite() is the low-level function to be called when data is to
                   1197:  * be read and written to/from the connection.
                   1198:  *
                   1199:  * return '*comeback' TRUE if we didn't properly drain the socket so this
                   1200:  * function should get called again without select() or similar in between!
                   1201:  */
                   1202: CURLcode Curl_readwrite(struct connectdata *conn,
                   1203:                         struct Curl_easy *data,
                   1204:                         bool *done,
                   1205:                         bool *comeback)
                   1206: {
                   1207:   struct SingleRequest *k = &data->req;
                   1208:   CURLcode result;
                   1209:   int didwhat = 0;
                   1210: 
                   1211:   curl_socket_t fd_read;
                   1212:   curl_socket_t fd_write;
                   1213:   int select_res = conn->cselect_bits;
                   1214: 
                   1215:   conn->cselect_bits = 0;
                   1216: 
                   1217:   /* only use the proper socket if the *_HOLD bit is not set simultaneously as
                   1218:      then we are in rate limiting state in that transfer direction */
                   1219: 
                   1220:   if((k->keepon & KEEP_RECVBITS) == KEEP_RECV)
                   1221:     fd_read = conn->sockfd;
                   1222:   else
                   1223:     fd_read = CURL_SOCKET_BAD;
                   1224: 
                   1225:   if((k->keepon & KEEP_SENDBITS) == KEEP_SEND)
                   1226:     fd_write = conn->writesockfd;
                   1227:   else
                   1228:     fd_write = CURL_SOCKET_BAD;
                   1229: 
                   1230:   if(conn->data->state.drain) {
                   1231:     select_res |= CURL_CSELECT_IN;
                   1232:     DEBUGF(infof(data, "Curl_readwrite: forcibly told to drain data\n"));
                   1233:   }
                   1234: 
                   1235:   if(!select_res) /* Call for select()/poll() only, if read/write/error
                   1236:                      status is not known. */
                   1237:     select_res = Curl_socket_check(fd_read, CURL_SOCKET_BAD, fd_write, 0);
                   1238: 
                   1239:   if(select_res == CURL_CSELECT_ERR) {
                   1240:     failf(data, "select/poll returned error");
                   1241:     return CURLE_SEND_ERROR;
                   1242:   }
                   1243: 
                   1244:   /* We go ahead and do a read if we have a readable socket or if
                   1245:      the stream was rewound (in which case we have data in a
                   1246:      buffer) */
                   1247:   if((k->keepon & KEEP_RECV) && (select_res & CURL_CSELECT_IN)) {
                   1248:     result = readwrite_data(data, conn, k, &didwhat, done, comeback);
                   1249:     if(result || *done)
                   1250:       return result;
                   1251:   }
                   1252: 
                   1253:   /* If we still have writing to do, we check if we have a writable socket. */
                   1254:   if((k->keepon & KEEP_SEND) && (select_res & CURL_CSELECT_OUT)) {
                   1255:     /* write */
                   1256: 
                   1257:     result = readwrite_upload(data, conn, &didwhat);
                   1258:     if(result)
                   1259:       return result;
                   1260:   }
                   1261: 
                   1262:   k->now = Curl_now();
                   1263:   if(didwhat) {
                   1264:     ;
                   1265:   }
                   1266:   else {
                   1267:     /* no read no write, this is a timeout? */
                   1268:     if(k->exp100 == EXP100_AWAITING_CONTINUE) {
                   1269:       /* This should allow some time for the header to arrive, but only a
                   1270:          very short time as otherwise it'll be too much wasted time too
                   1271:          often. */
                   1272: 
                   1273:       /* Quoting RFC2616, section "8.2.3 Use of the 100 (Continue) Status":
                   1274: 
                   1275:          Therefore, when a client sends this header field to an origin server
                   1276:          (possibly via a proxy) from which it has never seen a 100 (Continue)
                   1277:          status, the client SHOULD NOT wait for an indefinite period before
                   1278:          sending the request body.
                   1279: 
                   1280:       */
                   1281: 
                   1282:       timediff_t ms = Curl_timediff(k->now, k->start100);
                   1283:       if(ms >= data->set.expect_100_timeout) {
                   1284:         /* we've waited long enough, continue anyway */
                   1285:         k->exp100 = EXP100_SEND_DATA;
                   1286:         k->keepon |= KEEP_SEND;
                   1287:         Curl_expire_done(data, EXPIRE_100_TIMEOUT);
                   1288:         infof(data, "Done waiting for 100-continue\n");
                   1289:       }
                   1290:     }
                   1291:   }
                   1292: 
                   1293:   if(Curl_pgrsUpdate(conn))
                   1294:     result = CURLE_ABORTED_BY_CALLBACK;
                   1295:   else
                   1296:     result = Curl_speedcheck(data, k->now);
                   1297:   if(result)
                   1298:     return result;
                   1299: 
                   1300:   if(k->keepon) {
                   1301:     if(0 > Curl_timeleft(data, &k->now, FALSE)) {
                   1302:       if(k->size != -1) {
                   1303:         failf(data, "Operation timed out after %" CURL_FORMAT_TIMEDIFF_T
                   1304:               " milliseconds with %" CURL_FORMAT_CURL_OFF_T " out of %"
                   1305:               CURL_FORMAT_CURL_OFF_T " bytes received",
                   1306:               Curl_timediff(k->now, data->progress.t_startsingle),
                   1307:               k->bytecount, k->size);
                   1308:       }
                   1309:       else {
                   1310:         failf(data, "Operation timed out after %" CURL_FORMAT_TIMEDIFF_T
                   1311:               " milliseconds with %" CURL_FORMAT_CURL_OFF_T " bytes received",
                   1312:               Curl_timediff(k->now, data->progress.t_startsingle),
                   1313:               k->bytecount);
                   1314:       }
                   1315:       return CURLE_OPERATION_TIMEDOUT;
                   1316:     }
                   1317:   }
                   1318:   else {
                   1319:     /*
                   1320:      * The transfer has been performed. Just make some general checks before
                   1321:      * returning.
                   1322:      */
                   1323: 
                   1324:     if(!(data->set.opt_no_body) && (k->size != -1) &&
                   1325:        (k->bytecount != k->size) &&
                   1326: #ifdef CURL_DO_LINEEND_CONV
                   1327:        /* Most FTP servers don't adjust their file SIZE response for CRLFs,
                   1328:           so we'll check to see if the discrepancy can be explained
                   1329:           by the number of CRLFs we've changed to LFs.
                   1330:        */
                   1331:        (k->bytecount != (k->size + data->state.crlf_conversions)) &&
                   1332: #endif /* CURL_DO_LINEEND_CONV */
                   1333:        !k->newurl) {
                   1334:       failf(data, "transfer closed with %" CURL_FORMAT_CURL_OFF_T
                   1335:             " bytes remaining to read", k->size - k->bytecount);
                   1336:       return CURLE_PARTIAL_FILE;
                   1337:     }
                   1338:     if(!(data->set.opt_no_body) && k->chunk &&
                   1339:        (conn->chunk.state != CHUNK_STOP)) {
                   1340:       /*
                   1341:        * In chunked mode, return an error if the connection is closed prior to
                   1342:        * the empty (terminating) chunk is read.
                   1343:        *
                   1344:        * The condition above used to check for
                   1345:        * conn->proto.http->chunk.datasize != 0 which is true after reading
                   1346:        * *any* chunk, not just the empty chunk.
                   1347:        *
                   1348:        */
                   1349:       failf(data, "transfer closed with outstanding read data remaining");
                   1350:       return CURLE_PARTIAL_FILE;
                   1351:     }
                   1352:     if(Curl_pgrsUpdate(conn))
                   1353:       return CURLE_ABORTED_BY_CALLBACK;
                   1354:   }
                   1355: 
                   1356:   /* Now update the "done" boolean we return */
                   1357:   *done = (0 == (k->keepon&(KEEP_RECV|KEEP_SEND|
                   1358:                             KEEP_RECV_PAUSE|KEEP_SEND_PAUSE))) ? TRUE : FALSE;
                   1359: 
                   1360:   return CURLE_OK;
                   1361: }
                   1362: 
                   1363: /*
                   1364:  * Curl_single_getsock() gets called by the multi interface code when the app
                   1365:  * has requested to get the sockets for the current connection. This function
                   1366:  * will then be called once for every connection that the multi interface
                   1367:  * keeps track of. This function will only be called for connections that are
                   1368:  * in the proper state to have this information available.
                   1369:  */
                   1370: int Curl_single_getsock(const struct connectdata *conn,
                   1371:                         curl_socket_t *sock)
                   1372: {
                   1373:   const struct Curl_easy *data = conn->data;
                   1374:   int bitmap = GETSOCK_BLANK;
                   1375:   unsigned sockindex = 0;
                   1376: 
                   1377:   if(conn->handler->perform_getsock)
                   1378:     return conn->handler->perform_getsock(conn, sock);
                   1379: 
                   1380:   /* don't include HOLD and PAUSE connections */
                   1381:   if((data->req.keepon & KEEP_RECVBITS) == KEEP_RECV) {
                   1382: 
                   1383:     DEBUGASSERT(conn->sockfd != CURL_SOCKET_BAD);
                   1384: 
                   1385:     bitmap |= GETSOCK_READSOCK(sockindex);
                   1386:     sock[sockindex] = conn->sockfd;
                   1387:   }
                   1388: 
                   1389:   /* don't include HOLD and PAUSE connections */
                   1390:   if((data->req.keepon & KEEP_SENDBITS) == KEEP_SEND) {
                   1391: 
                   1392:     if((conn->sockfd != conn->writesockfd) ||
                   1393:        bitmap == GETSOCK_BLANK) {
                   1394:       /* only if they are not the same socket and we have a readable
                   1395:          one, we increase index */
                   1396:       if(bitmap != GETSOCK_BLANK)
                   1397:         sockindex++; /* increase index if we need two entries */
                   1398: 
                   1399:       DEBUGASSERT(conn->writesockfd != CURL_SOCKET_BAD);
                   1400: 
                   1401:       sock[sockindex] = conn->writesockfd;
                   1402:     }
                   1403: 
                   1404:     bitmap |= GETSOCK_WRITESOCK(sockindex);
                   1405:   }
                   1406: 
                   1407:   return bitmap;
                   1408: }
                   1409: 
                   1410: /* Curl_init_CONNECT() gets called each time the handle switches to CONNECT
                   1411:    which means this gets called once for each subsequent redirect etc */
                   1412: void Curl_init_CONNECT(struct Curl_easy *data)
                   1413: {
                   1414:   data->state.fread_func = data->set.fread_func_set;
                   1415:   data->state.in = data->set.in_set;
                   1416: }
                   1417: 
                   1418: /*
                   1419:  * Curl_pretransfer() is called immediately before a transfer starts, and only
                   1420:  * once for one transfer no matter if it has redirects or do multi-pass
                   1421:  * authentication etc.
                   1422:  */
                   1423: CURLcode Curl_pretransfer(struct Curl_easy *data)
                   1424: {
                   1425:   CURLcode result;
                   1426: 
                   1427:   if(!data->change.url && !data->set.uh) {
                   1428:     /* we can't do anything without URL */
                   1429:     failf(data, "No URL set!");
                   1430:     return CURLE_URL_MALFORMAT;
                   1431:   }
                   1432: 
                   1433:   /* since the URL may have been redirected in a previous use of this handle */
                   1434:   if(data->change.url_alloc) {
                   1435:     /* the already set URL is allocated, free it first! */
                   1436:     Curl_safefree(data->change.url);
                   1437:     data->change.url_alloc = FALSE;
                   1438:   }
                   1439: 
                   1440:   if(!data->change.url && data->set.uh) {
                   1441:     CURLUcode uc;
                   1442:     uc = curl_url_get(data->set.uh,
                   1443:                         CURLUPART_URL, &data->set.str[STRING_SET_URL], 0);
                   1444:     if(uc) {
                   1445:       failf(data, "No URL set!");
                   1446:       return CURLE_URL_MALFORMAT;
                   1447:     }
                   1448:   }
                   1449: 
                   1450:   data->change.url = data->set.str[STRING_SET_URL];
                   1451: 
                   1452:   /* Init the SSL session ID cache here. We do it here since we want to do it
                   1453:      after the *_setopt() calls (that could specify the size of the cache) but
                   1454:      before any transfer takes place. */
                   1455:   result = Curl_ssl_initsessions(data, data->set.general_ssl.max_ssl_sessions);
                   1456:   if(result)
                   1457:     return result;
                   1458: 
                   1459:   data->state.wildcardmatch = data->set.wildcard_enabled;
                   1460:   data->set.followlocation = 0; /* reset the location-follow counter */
                   1461:   data->state.this_is_a_follow = FALSE; /* reset this */
                   1462:   data->state.errorbuf = FALSE; /* no error has occurred */
                   1463:   data->state.httpversion = 0; /* don't assume any particular server version */
                   1464: 
                   1465:   data->state.authproblem = FALSE;
                   1466:   data->state.authhost.want = data->set.httpauth;
                   1467:   data->state.authproxy.want = data->set.proxyauth;
                   1468:   Curl_safefree(data->info.wouldredirect);
                   1469:   data->info.wouldredirect = NULL;
                   1470: 
                   1471:   if(data->set.httpreq == HTTPREQ_PUT)
                   1472:     data->state.infilesize = data->set.filesize;
                   1473:   else if((data->set.httpreq != HTTPREQ_GET) &&
                   1474:           (data->set.httpreq != HTTPREQ_HEAD)) {
                   1475:     data->state.infilesize = data->set.postfieldsize;
                   1476:     if(data->set.postfields && (data->state.infilesize == -1))
                   1477:       data->state.infilesize = (curl_off_t)strlen(data->set.postfields);
                   1478:   }
                   1479:   else
                   1480:     data->state.infilesize = 0;
                   1481: 
                   1482:   /* If there is a list of cookie files to read, do it now! */
                   1483:   if(data->change.cookielist)
                   1484:     Curl_cookie_loadfiles(data);
                   1485: 
                   1486:   /* If there is a list of host pairs to deal with */
                   1487:   if(data->change.resolve)
                   1488:     result = Curl_loadhostpairs(data);
                   1489: 
                   1490:   if(!result) {
                   1491:     /* Allow data->set.use_port to set which port to use. This needs to be
                   1492:      * disabled for example when we follow Location: headers to URLs using
                   1493:      * different ports! */
                   1494:     data->state.allow_port = TRUE;
                   1495: 
                   1496: #if defined(HAVE_SIGNAL) && defined(SIGPIPE) && !defined(HAVE_MSG_NOSIGNAL)
                   1497:     /*************************************************************
                   1498:      * Tell signal handler to ignore SIGPIPE
                   1499:      *************************************************************/
                   1500:     if(!data->set.no_signal)
                   1501:       data->state.prev_signal = signal(SIGPIPE, SIG_IGN);
                   1502: #endif
                   1503: 
                   1504:     Curl_initinfo(data); /* reset session-specific information "variables" */
                   1505:     Curl_pgrsResetTransferSizes(data);
                   1506:     Curl_pgrsStartNow(data);
                   1507: 
                   1508:     /* In case the handle is re-used and an authentication method was picked
                   1509:        in the session we need to make sure we only use the one(s) we now
                   1510:        consider to be fine */
                   1511:     data->state.authhost.picked &= data->state.authhost.want;
                   1512:     data->state.authproxy.picked &= data->state.authproxy.want;
                   1513: 
                   1514: #ifndef CURL_DISABLE_FTP
                   1515:     if(data->state.wildcardmatch) {
                   1516:       struct WildcardData *wc = &data->wildcard;
                   1517:       if(wc->state < CURLWC_INIT) {
                   1518:         result = Curl_wildcard_init(wc); /* init wildcard structures */
                   1519:         if(result)
                   1520:           return CURLE_OUT_OF_MEMORY;
                   1521:       }
                   1522:     }
                   1523: #endif
                   1524:     Curl_http2_init_state(&data->state);
                   1525:   }
                   1526: 
                   1527:   return result;
                   1528: }
                   1529: 
                   1530: /*
                   1531:  * Curl_posttransfer() is called immediately after a transfer ends
                   1532:  */
                   1533: CURLcode Curl_posttransfer(struct Curl_easy *data)
                   1534: {
                   1535: #if defined(HAVE_SIGNAL) && defined(SIGPIPE) && !defined(HAVE_MSG_NOSIGNAL)
                   1536:   /* restore the signal handler for SIGPIPE before we get back */
                   1537:   if(!data->set.no_signal)
                   1538:     signal(SIGPIPE, data->state.prev_signal);
                   1539: #else
                   1540:   (void)data; /* unused parameter */
                   1541: #endif
                   1542: 
                   1543:   return CURLE_OK;
                   1544: }
                   1545: 
                   1546: /*
                   1547:  * Curl_follow() handles the URL redirect magic. Pass in the 'newurl' string
                   1548:  * as given by the remote server and set up the new URL to request.
                   1549:  *
                   1550:  * This function DOES NOT FREE the given url.
                   1551:  */
                   1552: CURLcode Curl_follow(struct Curl_easy *data,
                   1553:                      char *newurl,    /* the Location: string */
                   1554:                      followtype type) /* see transfer.h */
                   1555: {
                   1556: #ifdef CURL_DISABLE_HTTP
                   1557:   (void)data;
                   1558:   (void)newurl;
                   1559:   (void)type;
                   1560:   /* Location: following will not happen when HTTP is disabled */
                   1561:   return CURLE_TOO_MANY_REDIRECTS;
                   1562: #else
                   1563: 
                   1564:   /* Location: redirect */
                   1565:   bool disallowport = FALSE;
                   1566:   bool reachedmax = FALSE;
                   1567:   CURLUcode uc;
                   1568: 
                   1569:   if(type == FOLLOW_REDIR) {
                   1570:     if((data->set.maxredirs != -1) &&
                   1571:        (data->set.followlocation >= data->set.maxredirs)) {
                   1572:       reachedmax = TRUE;
                   1573:       type = FOLLOW_FAKE; /* switch to fake to store the would-be-redirected
                   1574:                              to URL */
                   1575:     }
                   1576:     else {
                   1577:       /* mark the next request as a followed location: */
                   1578:       data->state.this_is_a_follow = TRUE;
                   1579: 
                   1580:       data->set.followlocation++; /* count location-followers */
                   1581: 
                   1582:       if(data->set.http_auto_referer) {
                   1583:         /* We are asked to automatically set the previous URL as the referer
                   1584:            when we get the next URL. We pick the ->url field, which may or may
                   1585:            not be 100% correct */
                   1586: 
                   1587:         if(data->change.referer_alloc) {
                   1588:           Curl_safefree(data->change.referer);
                   1589:           data->change.referer_alloc = FALSE;
                   1590:         }
                   1591: 
                   1592:         data->change.referer = strdup(data->change.url);
                   1593:         if(!data->change.referer)
                   1594:           return CURLE_OUT_OF_MEMORY;
                   1595:         data->change.referer_alloc = TRUE; /* yes, free this later */
                   1596:       }
                   1597:     }
                   1598:   }
                   1599: 
                   1600:   if(Curl_is_absolute_url(newurl, NULL, MAX_SCHEME_LEN))
                   1601:     /* This is an absolute URL, don't allow the custom port number */
                   1602:     disallowport = TRUE;
                   1603: 
                   1604:   DEBUGASSERT(data->state.uh);
                   1605:   uc = curl_url_set(data->state.uh, CURLUPART_URL, newurl,
                   1606:                     (type == FOLLOW_FAKE) ? CURLU_NON_SUPPORT_SCHEME :
                   1607:                     ((type == FOLLOW_REDIR) ? CURLU_URLENCODE : 0) );
                   1608:   if(uc) {
                   1609:     if(type != FOLLOW_FAKE)
                   1610:       return Curl_uc_to_curlcode(uc);
                   1611: 
                   1612:     /* the URL could not be parsed for some reason, but since this is FAKE
                   1613:        mode, just duplicate the field as-is */
                   1614:     newurl = strdup(newurl);
                   1615:     if(!newurl)
                   1616:       return CURLE_OUT_OF_MEMORY;
                   1617:   }
                   1618:   else {
                   1619: 
                   1620:     uc = curl_url_get(data->state.uh, CURLUPART_URL, &newurl, 0);
                   1621:     if(uc)
                   1622:       return Curl_uc_to_curlcode(uc);
                   1623:   }
                   1624: 
                   1625:   if(type == FOLLOW_FAKE) {
                   1626:     /* we're only figuring out the new url if we would've followed locations
                   1627:        but now we're done so we can get out! */
                   1628:     data->info.wouldredirect = newurl;
                   1629: 
                   1630:     if(reachedmax) {
                   1631:       failf(data, "Maximum (%ld) redirects followed", data->set.maxredirs);
                   1632:       return CURLE_TOO_MANY_REDIRECTS;
                   1633:     }
                   1634:     return CURLE_OK;
                   1635:   }
                   1636: 
                   1637:   if(disallowport)
                   1638:     data->state.allow_port = FALSE;
                   1639: 
                   1640:   if(data->change.url_alloc)
                   1641:     Curl_safefree(data->change.url);
                   1642: 
                   1643:   data->change.url = newurl;
                   1644:   data->change.url_alloc = TRUE;
                   1645: 
                   1646:   infof(data, "Issue another request to this URL: '%s'\n", data->change.url);
                   1647: 
                   1648:   /*
                   1649:    * We get here when the HTTP code is 300-399 (and 401). We need to perform
                   1650:    * differently based on exactly what return code there was.
                   1651:    *
                   1652:    * News from 7.10.6: we can also get here on a 401 or 407, in case we act on
                   1653:    * a HTTP (proxy-) authentication scheme other than Basic.
                   1654:    */
                   1655:   switch(data->info.httpcode) {
                   1656:     /* 401 - Act on a WWW-Authenticate, we keep on moving and do the
                   1657:        Authorization: XXXX header in the HTTP request code snippet */
                   1658:     /* 407 - Act on a Proxy-Authenticate, we keep on moving and do the
                   1659:        Proxy-Authorization: XXXX header in the HTTP request code snippet */
                   1660:     /* 300 - Multiple Choices */
                   1661:     /* 306 - Not used */
                   1662:     /* 307 - Temporary Redirect */
                   1663:   default:  /* for all above (and the unknown ones) */
                   1664:     /* Some codes are explicitly mentioned since I've checked RFC2616 and they
                   1665:      * seem to be OK to POST to.
                   1666:      */
                   1667:     break;
                   1668:   case 301: /* Moved Permanently */
                   1669:     /* (quote from RFC7231, section 6.4.2)
                   1670:      *
                   1671:      * Note: For historical reasons, a user agent MAY change the request
                   1672:      * method from POST to GET for the subsequent request.  If this
                   1673:      * behavior is undesired, the 307 (Temporary Redirect) status code
                   1674:      * can be used instead.
                   1675:      *
                   1676:      * ----
                   1677:      *
                   1678:      * Many webservers expect this, so these servers often answers to a POST
                   1679:      * request with an error page. To be sure that libcurl gets the page that
                   1680:      * most user agents would get, libcurl has to force GET.
                   1681:      *
                   1682:      * This behaviour is forbidden by RFC1945 and the obsolete RFC2616, and
                   1683:      * can be overridden with CURLOPT_POSTREDIR.
                   1684:      */
                   1685:     if((data->set.httpreq == HTTPREQ_POST
                   1686:         || data->set.httpreq == HTTPREQ_POST_FORM
                   1687:         || data->set.httpreq == HTTPREQ_POST_MIME)
                   1688:        && !(data->set.keep_post & CURL_REDIR_POST_301)) {
                   1689:       infof(data, "Switch from POST to GET\n");
                   1690:       data->set.httpreq = HTTPREQ_GET;
                   1691:     }
                   1692:     break;
                   1693:   case 302: /* Found */
                   1694:     /* (quote from RFC7231, section 6.4.3)
                   1695:      *
                   1696:      * Note: For historical reasons, a user agent MAY change the request
                   1697:      * method from POST to GET for the subsequent request.  If this
                   1698:      * behavior is undesired, the 307 (Temporary Redirect) status code
                   1699:      * can be used instead.
                   1700:      *
                   1701:      * ----
                   1702:      *
                   1703:      * Many webservers expect this, so these servers often answers to a POST
                   1704:      * request with an error page. To be sure that libcurl gets the page that
                   1705:      * most user agents would get, libcurl has to force GET.
                   1706:      *
                   1707:      * This behaviour is forbidden by RFC1945 and the obsolete RFC2616, and
                   1708:      * can be overridden with CURLOPT_POSTREDIR.
                   1709:      */
                   1710:     if((data->set.httpreq == HTTPREQ_POST
                   1711:         || data->set.httpreq == HTTPREQ_POST_FORM
                   1712:         || data->set.httpreq == HTTPREQ_POST_MIME)
                   1713:        && !(data->set.keep_post & CURL_REDIR_POST_302)) {
                   1714:       infof(data, "Switch from POST to GET\n");
                   1715:       data->set.httpreq = HTTPREQ_GET;
                   1716:     }
                   1717:     break;
                   1718: 
                   1719:   case 303: /* See Other */
                   1720:     /* 'See Other' location is not the resource but a substitute for the
                   1721:      * resource. In this case we switch the method to GET/HEAD, unless the
                   1722:      * method is POST and the user specified to keep it as POST.
                   1723:      * https://github.com/curl/curl/issues/5237#issuecomment-614641049
                   1724:      */
                   1725:     if(data->set.httpreq != HTTPREQ_GET &&
                   1726:        ((data->set.httpreq != HTTPREQ_POST &&
                   1727:          data->set.httpreq != HTTPREQ_POST_FORM &&
                   1728:          data->set.httpreq != HTTPREQ_POST_MIME) ||
                   1729:         !(data->set.keep_post & CURL_REDIR_POST_303))) {
                   1730:       data->set.httpreq = HTTPREQ_GET;
                   1731:       data->set.upload = false;
                   1732:       infof(data, "Switch to %s\n",
                   1733:             data->set.opt_no_body?"HEAD":"GET");
                   1734:     }
                   1735:     break;
                   1736:   case 304: /* Not Modified */
                   1737:     /* 304 means we did a conditional request and it was "Not modified".
                   1738:      * We shouldn't get any Location: header in this response!
                   1739:      */
                   1740:     break;
                   1741:   case 305: /* Use Proxy */
                   1742:     /* (quote from RFC2616, section 10.3.6):
                   1743:      * "The requested resource MUST be accessed through the proxy given
                   1744:      * by the Location field. The Location field gives the URI of the
                   1745:      * proxy.  The recipient is expected to repeat this single request
                   1746:      * via the proxy. 305 responses MUST only be generated by origin
                   1747:      * servers."
                   1748:      */
                   1749:     break;
                   1750:   }
                   1751:   Curl_pgrsTime(data, TIMER_REDIRECT);
                   1752:   Curl_pgrsResetTransferSizes(data);
                   1753: 
                   1754:   return CURLE_OK;
                   1755: #endif /* CURL_DISABLE_HTTP */
                   1756: }
                   1757: 
                   1758: /* Returns CURLE_OK *and* sets '*url' if a request retry is wanted.
                   1759: 
                   1760:    NOTE: that the *url is malloc()ed. */
                   1761: CURLcode Curl_retry_request(struct connectdata *conn,
                   1762:                             char **url)
                   1763: {
                   1764:   struct Curl_easy *data = conn->data;
                   1765:   bool retry = FALSE;
                   1766:   *url = NULL;
                   1767: 
                   1768:   /* if we're talking upload, we can't do the checks below, unless the protocol
                   1769:      is HTTP as when uploading over HTTP we will still get a response */
                   1770:   if(data->set.upload &&
                   1771:      !(conn->handler->protocol&(PROTO_FAMILY_HTTP|CURLPROTO_RTSP)))
                   1772:     return CURLE_OK;
                   1773: 
                   1774:   if((data->req.bytecount + data->req.headerbytecount == 0) &&
                   1775:       conn->bits.reuse &&
                   1776:       (!data->set.opt_no_body
                   1777:         || (conn->handler->protocol & PROTO_FAMILY_HTTP)) &&
                   1778:       (data->set.rtspreq != RTSPREQ_RECEIVE))
                   1779:     /* We got no data, we attempted to re-use a connection. For HTTP this
                   1780:        can be a retry so we try again regardless if we expected a body.
                   1781:        For other protocols we only try again only if we expected a body.
                   1782: 
                   1783:        This might happen if the connection was left alive when we were
                   1784:        done using it before, but that was closed when we wanted to read from
                   1785:        it again. Bad luck. Retry the same request on a fresh connect! */
                   1786:     retry = TRUE;
                   1787:   else if(data->state.refused_stream &&
                   1788:           (data->req.bytecount + data->req.headerbytecount == 0) ) {
                   1789:     /* This was sent on a refused stream, safe to rerun. A refused stream
                   1790:        error can typically only happen on HTTP/2 level if the stream is safe
                   1791:        to issue again, but the nghttp2 API can deliver the message to other
                   1792:        streams as well, which is why this adds the check the data counters
                   1793:        too. */
                   1794:     infof(conn->data, "REFUSED_STREAM, retrying a fresh connect\n");
                   1795:     data->state.refused_stream = FALSE; /* clear again */
                   1796:     retry = TRUE;
                   1797:   }
                   1798:   if(retry) {
                   1799: #define CONN_MAX_RETRIES 5
                   1800:     if(conn->retrycount++ >= CONN_MAX_RETRIES) {
                   1801:       failf(data, "Connection died, tried %d times before giving up",
                   1802:             CONN_MAX_RETRIES);
                   1803:       return CURLE_SEND_ERROR;
                   1804:     }
                   1805:     infof(conn->data, "Connection died, retrying a fresh connect\n");
                   1806:     *url = strdup(conn->data->change.url);
                   1807:     if(!*url)
                   1808:       return CURLE_OUT_OF_MEMORY;
                   1809: 
                   1810:     connclose(conn, "retry"); /* close this connection */
                   1811:     conn->bits.retry = TRUE; /* mark this as a connection we're about
                   1812:                                 to retry. Marking it this way should
                   1813:                                 prevent i.e HTTP transfers to return
                   1814:                                 error just because nothing has been
                   1815:                                 transferred! */
                   1816: 
                   1817: 
                   1818:     if(conn->handler->protocol&PROTO_FAMILY_HTTP) {
                   1819:       if(data->req.writebytecount) {
                   1820:         CURLcode result = Curl_readrewind(conn);
                   1821:         if(result) {
                   1822:           Curl_safefree(*url);
                   1823:           return result;
                   1824:         }
                   1825:       }
                   1826:     }
                   1827:   }
                   1828:   return CURLE_OK;
                   1829: }
                   1830: 
                   1831: /*
                   1832:  * Curl_setup_transfer() is called to setup some basic properties for the
                   1833:  * upcoming transfer.
                   1834:  */
                   1835: void
                   1836: Curl_setup_transfer(
                   1837:   struct Curl_easy *data,   /* transfer */
                   1838:   int sockindex,            /* socket index to read from or -1 */
                   1839:   curl_off_t size,          /* -1 if unknown at this point */
                   1840:   bool getheader,           /* TRUE if header parsing is wanted */
                   1841:   int writesockindex        /* socket index to write to, it may very well be
                   1842:                                the same we read from. -1 disables */
                   1843:   )
                   1844: {
                   1845:   struct SingleRequest *k = &data->req;
                   1846:   struct connectdata *conn = data->conn;
                   1847:   struct HTTP *http = data->req.protop;
                   1848:   bool httpsending = ((conn->handler->protocol&PROTO_FAMILY_HTTP) &&
                   1849:                       (http->sending == HTTPSEND_REQUEST));
                   1850:   DEBUGASSERT(conn != NULL);
                   1851:   DEBUGASSERT((sockindex <= 1) && (sockindex >= -1));
                   1852: 
                   1853:   if(conn->bits.multiplex || conn->httpversion == 20 || httpsending) {
                   1854:     /* when multiplexing, the read/write sockets need to be the same! */
                   1855:     conn->sockfd = sockindex == -1 ?
                   1856:       ((writesockindex == -1 ? CURL_SOCKET_BAD : conn->sock[writesockindex])) :
                   1857:       conn->sock[sockindex];
                   1858:     conn->writesockfd = conn->sockfd;
                   1859:     if(httpsending)
                   1860:       /* special and very HTTP-specific */
                   1861:       writesockindex = FIRSTSOCKET;
                   1862:   }
                   1863:   else {
                   1864:     conn->sockfd = sockindex == -1 ?
                   1865:       CURL_SOCKET_BAD : conn->sock[sockindex];
                   1866:     conn->writesockfd = writesockindex == -1 ?
                   1867:       CURL_SOCKET_BAD:conn->sock[writesockindex];
                   1868:   }
                   1869:   k->getheader = getheader;
                   1870: 
                   1871:   k->size = size;
                   1872: 
                   1873:   /* The code sequence below is placed in this function just because all
                   1874:      necessary input is not always known in do_complete() as this function may
                   1875:      be called after that */
                   1876: 
                   1877:   if(!k->getheader) {
                   1878:     k->header = FALSE;
                   1879:     if(size > 0)
                   1880:       Curl_pgrsSetDownloadSize(data, size);
                   1881:   }
                   1882:   /* we want header and/or body, if neither then don't do this! */
                   1883:   if(k->getheader || !data->set.opt_no_body) {
                   1884: 
                   1885:     if(sockindex != -1)
                   1886:       k->keepon |= KEEP_RECV;
                   1887: 
                   1888:     if(writesockindex != -1) {
                   1889:       /* HTTP 1.1 magic:
                   1890: 
                   1891:          Even if we require a 100-return code before uploading data, we might
                   1892:          need to write data before that since the REQUEST may not have been
                   1893:          finished sent off just yet.
                   1894: 
                   1895:          Thus, we must check if the request has been sent before we set the
                   1896:          state info where we wait for the 100-return code
                   1897:       */
                   1898:       if((data->state.expect100header) &&
                   1899:          (conn->handler->protocol&PROTO_FAMILY_HTTP) &&
                   1900:          (http->sending == HTTPSEND_BODY)) {
                   1901:         /* wait with write until we either got 100-continue or a timeout */
                   1902:         k->exp100 = EXP100_AWAITING_CONTINUE;
                   1903:         k->start100 = Curl_now();
                   1904: 
                   1905:         /* Set a timeout for the multi interface. Add the inaccuracy margin so
                   1906:            that we don't fire slightly too early and get denied to run. */
                   1907:         Curl_expire(data, data->set.expect_100_timeout, EXPIRE_100_TIMEOUT);
                   1908:       }
                   1909:       else {
                   1910:         if(data->state.expect100header)
                   1911:           /* when we've sent off the rest of the headers, we must await a
                   1912:              100-continue but first finish sending the request */
                   1913:           k->exp100 = EXP100_SENDING_REQUEST;
                   1914: 
                   1915:         /* enable the write bit when we're not waiting for continue */
                   1916:         k->keepon |= KEEP_SEND;
                   1917:       }
                   1918:     } /* if(writesockindex != -1) */
                   1919:   } /* if(k->getheader || !data->set.opt_no_body) */
                   1920: 
                   1921: }

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