webcit/context_loop.c

   1 /*
   2  * This is the other half of the webserver.  It handles the task of hooking
   3  * up HTTP requests with the sessions they belong to, using HTTP cookies to
   4  * keep track of things.  If the HTTP request doesn't belong to any currently
   5  * active session, a new session is started.
   6  *
   7  * Copyright (c) 1996-2012 by the citadel.org team
   8  *
   9  * This program is open source software.  You can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License version 3.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include "webcit.h"
  19 #include "webserver.h"
  20 #include "modules_init.h"
  21
  22 /* Only one thread may manipulate SessionList at a time... */
  23 pthread_mutex_t SessionListMutex;
  24
  25 wcsession *SessionList = NULL;  /* Linked list of all webcit sessions */
  26
  27 pthread_key_t MyConKey;         /* TSD key for MySession() */
  28 HashList *HttpReqTypes = NULL;
  29 HashList *HttpHeaderHandler = NULL;
  30 extern HashList *HandlerHash;
  31
  32 /* the following two values start at 1 because the initial parent thread counts as one. */
  33 int num_threads_existing = 1;           /* Number of worker threads which exist. */
  34 int num_threads_executing = 1;          /* Number of worker threads currently executing. */
  35
  36 extern void session_loop(void);
  37 void spawn_another_worker_thread(void);
  38
  39
  40 void DestroyHttpHeaderHandler(void *V)
  41 {
  42         OneHttpHeader *pHdr;
  43         pHdr = (OneHttpHeader*) V;
  44         FreeStrBuf(&pHdr->Val);
  45         free(pHdr);
  46 }
  47
  48 void shutdown_sessions(void)
  49 {
  50         wcsession *sptr;
  51
  52         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  53                 sptr->killthis = 1;
  54         }
  55 }
  56
  57 void do_housekeeping(void)
  58 {
  59         wcsession *sptr, *ss;
  60         wcsession *sessions_to_kill = NULL;
  61         time_t the_time;
  62
  63         /*
  64          * Lock the session list, moving any candidates for euthanasia into
  65          * a separate list.
  66          */
  67         the_time = 0;
  68         CtdlLogResult(pthread_mutex_lock(&SessionListMutex));
  69         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  70                 if (the_time == 0)
  71                         the_time = time(NULL);
  72                 /* Kill idle sessions */
  73                 if ((sptr->inuse == 0) &&
  74                     ((the_time - (sptr->lastreq)) > (time_t) WEBCIT_TIMEOUT))
  75                 {
  76                         syslog(LOG_DEBUG, "Timeout session %d", sptr->wc_session);
  77                         sptr->killthis = 1;
  78                 }
  79
  80                 /* Remove sessions flagged for kill */
  81                 if (sptr->killthis) {
  82
  83                         /* remove session from linked list */
  84                         if (sptr == SessionList) {
  85                                 SessionList = SessionList->next;
  86                         }
  87                         else for (ss=SessionList;ss!=NULL;ss=ss->next) {
  88                                 if (ss->next == sptr) {
  89                                         ss->next = ss->next->next;
  90                                 }
  91                         }
  92
  93                         sptr->next = sessions_to_kill;
  94                         sessions_to_kill = sptr;
  95                 }
  96         }
  97         CtdlLogResult(pthread_mutex_unlock(&SessionListMutex));
  98
  99         /*
 100          * Now free up and destroy the culled sessions.
 101          */
 102         while (sessions_to_kill != NULL) {
 103                 syslog(LOG_DEBUG, "Destroying session %d", sessions_to_kill->wc_session);
 104                 sptr = sessions_to_kill->next;
 105                 session_destroy_modules(&sessions_to_kill);
 106                 sessions_to_kill = sptr;
 107         }
 108 }
 109
 110 /*
 111  * Check the size of our thread pool.  If all threads are executing, spawn another.
 112  */
 113 void check_thread_pool_size(void)
 114 {
 115         if (time_to_die) return;                /* don't expand the thread pool during shutdown */
 116
 117         begin_critical_section(S_SPAWNER);      /* only one of these should run at a time */
 118         if (
 119                 (num_threads_executing >= num_threads_existing)
 120                 && (num_threads_existing < MAX_WORKER_THREADS)
 121         ) {
 122                 syslog(LOG_DEBUG, "%d of %d threads are executing.  Adding another worker thread.",
 123                         num_threads_executing,
 124                         num_threads_existing
 125                 );
 126                 spawn_another_worker_thread();
 127         }
 128         end_critical_section(S_SPAWNER);
 129 }
 130
 131
 132 /*
 133  * Wake up occasionally and clean house
 134  */
 135 void housekeeping_loop(void)
 136 {
 137         while (1) {
 138                 sleeeeeeeeeep(HOUSEKEEPING);
 139                 do_housekeeping();
 140         }
 141 }
 142
 143
 144 /*
 145  * Create a Session id
 146  * Generate a unique WebCit session ID (which is not the same thing as the
 147  * Citadel session ID).
 148  */
 149 int GenerateSessionID(void)
 150 {
 151         static int seq = (-1);
 152
 153         if (seq < 0) {
 154                 seq = (int) time(NULL);
 155         }
 156
 157         return ++seq;
 158 }
 159
 160 wcsession *FindSession(wcsession **wclist, ParsedHttpHdrs *Hdr, pthread_mutex_t *ListMutex)
 161 {
 162         wcsession *sptr = NULL;
 163         wcsession *TheSession = NULL;
 164
 165         if (Hdr->HR.got_auth == AUTH_BASIC) {
 166                 GetAuthBasic(Hdr);
 167         }
 168
 169         CtdlLogResult(pthread_mutex_lock(ListMutex));
 170         for (sptr = *wclist; ((sptr != NULL) && (TheSession == NULL)); sptr = sptr->next) {
 171
 172                 /* If HTTP-AUTH, look for a session with matching credentials */
 173                 switch (Hdr->HR.got_auth)
 174                 {
 175                 case AUTH_BASIC:
 176                         if (    (!strcasecmp(ChrPtr(Hdr->c_username), ChrPtr(sptr->wc_username)))
 177                                 && (!strcasecmp(ChrPtr(Hdr->c_password), ChrPtr(sptr->wc_password)))
 178                                 && (sptr->killthis == 0)
 179                         ) {
 180                                 syslog(LOG_DEBUG, "Matched a session with the same http-auth");
 181                                 TheSession = sptr;
 182                         }
 183                         break;
 184                 case AUTH_COOKIE:
 185                         /* If cookie-session, look for a session with matching session ID */
 186                         if (    (Hdr->HR.desired_session != 0)
 187                                 && (sptr->wc_session == Hdr->HR.desired_session)
 188                         ) {
 189                                 syslog(LOG_DEBUG, "Matched a session with the same cookie");
 190                                 TheSession = sptr;
 191                         }
 192                         break;
 193                 case NO_AUTH:
 194                         /* Any unbound session is a candidate */
 195                         if ( (sptr->wc_session == 0) && (sptr->inuse == 0) ) {
 196                                 syslog(LOG_DEBUG, "Reusing an unbound session");
 197                                 TheSession = sptr;
 198                         }
 199                         break;
 200                 }
 201         }
 202         CtdlLogResult(pthread_mutex_unlock(ListMutex));
 203         if (TheSession == NULL) {
 204                 syslog(LOG_DEBUG, "No existing session was matched");
 205         }
 206         return TheSession;
 207 }
 208
 209 wcsession *CreateSession(int Lockable, int Static, wcsession **wclist, ParsedHttpHdrs *Hdr, pthread_mutex_t *ListMutex)
 210 {
 211         wcsession *TheSession;
 212         TheSession = (wcsession *) malloc(sizeof(wcsession));
 213         memset(TheSession, 0, sizeof(wcsession));
 214         TheSession->Hdr = Hdr;
 215         TheSession->serv_sock = (-1);
 216         TheSession->lastreq = time(NULL);;
 217
 218         pthread_setspecific(MyConKey, (void *)TheSession);
 219
 220         /* If we're recreating a session that expired, it's best to give it the same
 221          * session number that it had before.  The client browser ought to pick up
 222          * the new session number and start using it, but in some rare situations it
 223          * doesn't, and that's a Bad Thing because it causes lots of spurious sessions
 224          * to get created.
 225          */
 226         if (Hdr->HR.desired_session == 0) {
 227                 TheSession->wc_session = GenerateSessionID();
 228                 syslog(LOG_DEBUG, "Created new session %d", TheSession->wc_session);
 229         }
 230         else {
 231                 TheSession->wc_session = Hdr->HR.desired_session;
 232                 syslog(LOG_DEBUG, "Re-created session %d", TheSession->wc_session);
 233         }
 234         Hdr->HR.Static = Static;
 235         session_new_modules(TheSession);
 236
 237         if (Lockable) {
 238                 pthread_mutex_init(&TheSession->SessionMutex, NULL);
 239
 240                 if (ListMutex != NULL)
 241                         CtdlLogResult(pthread_mutex_lock(ListMutex));
 242
 243                 if (wclist != NULL) {
 244                         TheSession->nonce = rand();
 245                         TheSession->next = *wclist;
 246                         *wclist = TheSession;
 247                 }
 248                 if (ListMutex != NULL)
 249                         CtdlLogResult(pthread_mutex_unlock(ListMutex));
 250         }
 251         return TheSession;
 252 }
 253
 254
 255 /* If it's a "force 404" situation then display the error and bail. */
 256 void do_404(void)
 257 {
 258         hprintf("HTTP/1.1 404 Not found\r\n");
 259         hprintf("Content-Type: text/plain\r\n");
 260         wc_printf("Not found\r\n");
 261         end_burst();
 262 }
 263
 264 int ReadHttpSubject(ParsedHttpHdrs *Hdr, StrBuf *Line, StrBuf *Buf)
 265 {
 266         const char *Args;
 267         void *vLine, *vHandler;
 268         const char *Pos = NULL;
 269
 270         Hdr->HR.ReqLine = Line;
 271         /* The requesttype... GET, POST... */
 272         StrBufExtract_token(Buf, Hdr->HR.ReqLine, 0, ' ');
 273         if (GetHash(HttpReqTypes, SKEY(Buf), &vLine) &&
 274             (vLine != NULL))
 275         {
 276                 Hdr->HR.eReqType = *(long*)vLine;
 277         }
 278         else {
 279                 Hdr->HR.eReqType = eGET;
 280                 return 1;
 281         }
 282         StrBufCutLeft(Hdr->HR.ReqLine, StrLength(Buf) + 1);
 283
 284         /* the HTTP Version... */
 285         StrBufExtract_token(Buf, Hdr->HR.ReqLine, 1, ' ');
 286         StrBufCutRight(Hdr->HR.ReqLine, StrLength(Buf) + 1);
 287
 288         if (StrLength(Buf) == 0) {
 289                 Hdr->HR.eReqType = eGET;
 290                 return 1;
 291         }
 292
 293         StrBufAppendBuf(Hdr->this_page, Hdr->HR.ReqLine, 0);
 294
 295         /* chop Filename / query arguments */
 296         Args = strchr(ChrPtr(Hdr->HR.ReqLine), '?');
 297         if (Args == NULL) /* whe're not that picky about params... TODO: this will spoil '&' in filenames.*/
 298                 Args = strchr(ChrPtr(Hdr->HR.ReqLine), '&');
 299         if (Args != NULL) {
 300                 Args ++; /* skip the ? */
 301                 StrBufPlain(Hdr->PlainArgs,
 302                             Args,
 303                             StrLength(Hdr->HR.ReqLine) -
 304                             (Args - ChrPtr(Hdr->HR.ReqLine)));
 305                 StrBufCutAt(Hdr->HR.ReqLine, 0, Args - 1);
 306         } /* don't parse them yet, maybe we don't even care... */
 307
 308         /* now lookup what we are going to do with this... */
 309         /* skip first slash */
 310         StrBufExtract_NextToken(Buf, Hdr->HR.ReqLine, &Pos, '/');
 311         do {
 312                 StrBufExtract_NextToken(Buf, Hdr->HR.ReqLine, &Pos, '/');
 313
 314                 GetHash(HandlerHash, SKEY(Buf), &vHandler),
 315                 Hdr->HR.Handler = (WebcitHandler*) vHandler;
 316                 if (Hdr->HR.Handler == NULL)
 317                         break;
 318                 /*
 319                  * If the request is prefixed by "/webcit" then chop that off.  This
 320                  * allows a front end web server to forward all /webcit requests to us
 321                  * while still using the same web server port for other things.
 322                  */
 323                 if ((Hdr->HR.Handler->Flags & URLNAMESPACE) != 0)
 324                         continue;
 325                 break;
 326         } while (1);
 327         /* remove the handlername from the URL */
 328         if ((Pos != NULL) && (Pos != StrBufNOTNULL)){
 329                 StrBufCutLeft(Hdr->HR.ReqLine,
 330                               Pos - ChrPtr(Hdr->HR.ReqLine));
 331         }
 332
 333         if (Hdr->HR.Handler != NULL) {
 334                 if ((Hdr->HR.Handler->Flags & BOGUS) != 0) {
 335                         return 1;
 336                 }
 337                 Hdr->HR.DontNeedAuth = (
 338                         ((Hdr->HR.Handler->Flags & ISSTATIC) != 0) ||
 339                         ((Hdr->HR.Handler->Flags & ANONYMOUS) != 0)
 340                 );
 341         }
 342         else {
 343                 /* If this is a "flat" request for the root, display the configured landing page. */
 344                 int return_value;
 345                 StrBuf *NewLine = NewStrBuf();
 346                 Hdr->HR.DontNeedAuth = 1;
 347                 StrBufAppendPrintf(NewLine, "GET /landing?go=%s HTTP/1.0", ChrPtr(Buf));
 348                 syslog(LOG_DEBUG, "Replacing with: %s", ChrPtr(NewLine));
 349                 return_value = ReadHttpSubject(Hdr, NewLine, Buf);
 350                 FreeStrBuf(&NewLine);
 351                 return return_value;
 352         }
 353
 354         return 0;
 355 }
 356
 357 int AnalyseHeaders(ParsedHttpHdrs *Hdr)
 358 {
 359         OneHttpHeader *pHdr;
 360         void *vHdr;
 361         long HKLen;
 362         const char *HashKey;
 363         HashPos *at = GetNewHashPos(Hdr->HTTPHeaders, 0);
 364
 365         while (GetNextHashPos(Hdr->HTTPHeaders, at, &HKLen, &HashKey, &vHdr) &&
 366                (vHdr != NULL)) {
 367                 pHdr = (OneHttpHeader *)vHdr;
 368                 if (pHdr->HaveEvaluator)
 369                         pHdr->H(pHdr->Val, Hdr);
 370
 371         }
 372         DeleteHashPos(&at);
 373         return 0;
 374 }
 375
 376 /*const char *nix(void *vptr) {return ChrPtr( (StrBuf*)vptr);}*/
 377
 378 /*
 379  * Read in the request
 380  */
 381 int ReadHTTPRequest (ParsedHttpHdrs *Hdr)
 382 {
 383         const char *pch, *pchs, *pche;
 384         OneHttpHeader *pHdr;
 385         StrBuf *Line, *LastLine, *HeaderName;
 386         int nLine = 0;
 387         void *vF;
 388         int isbogus = 0;
 389
 390         HeaderName = NewStrBuf();
 391         LastLine = NULL;
 392         do {
 393                 nLine ++;
 394                 Line = NewStrBufPlain(NULL, SIZ / 4);
 395
 396                 if (ClientGetLine(Hdr, Line) < 0) return 1;
 397
 398                 if (StrLength(Line) == 0) {
 399                         FreeStrBuf(&Line);
 400                         continue;
 401                 }
 402                 if (nLine == 1) {
 403                         Hdr->HTTPHeaders = NewHash(1, NULL);
 404                         pHdr = (OneHttpHeader*) malloc(sizeof(OneHttpHeader));
 405                         memset(pHdr, 0, sizeof(OneHttpHeader));
 406                         pHdr->Val = Line;
 407                         Put(Hdr->HTTPHeaders, HKEY("GET /"), pHdr, DestroyHttpHeaderHandler);
 408                         syslog(LOG_DEBUG, "%s", ChrPtr(Line));
 409                         isbogus = ReadHttpSubject(Hdr, Line, HeaderName);
 410                         if (isbogus) break;
 411                         continue;
 412                 }
 413
 414                 /* Do we need to Unfold? */
 415                 if ((LastLine != NULL) &&
 416                     (isspace(*ChrPtr(Line)))) {
 417                         pch = pchs = ChrPtr(Line);
 418                         pche = pchs + StrLength(Line);
 419                         while (isspace(*pch) && (pch < pche))
 420                                 pch ++;
 421                         StrBufCutLeft(Line, pch - pchs);
 422                         StrBufAppendBuf(LastLine, Line, 0);
 423
 424                         FreeStrBuf(&Line);
 425                         continue;
 426                 }
 427
 428                 StrBufSanitizeAscii(Line, '§');
 429                 StrBufExtract_token(HeaderName, Line, 0, ':');
 430
 431                 pchs = ChrPtr(Line);
 432                 pche = pchs + StrLength(Line);
 433                 pch = pchs + StrLength(HeaderName) + 1;
 434                 pche = pchs + StrLength(Line);
 435                 while ((pch < pche) && isspace(*pch))
 436                         pch ++;
 437                 StrBufCutLeft(Line, pch - pchs);
 438
 439                 StrBufUpCase(HeaderName);
 440
 441                 pHdr = (OneHttpHeader*) malloc(sizeof(OneHttpHeader));
 442                 memset(pHdr, 0, sizeof(OneHttpHeader));
 443                 pHdr->Val = Line;
 444
 445                 if (GetHash(HttpHeaderHandler, SKEY(HeaderName), &vF) &&
 446                     (vF != NULL))
 447                 {
 448                         OneHttpHeader *FHdr = (OneHttpHeader*) vF;
 449                         pHdr->H = FHdr->H;
 450                         pHdr->HaveEvaluator = 1;
 451                 }
 452                 Put(Hdr->HTTPHeaders, SKEY(HeaderName), pHdr, DestroyHttpHeaderHandler);
 453                 LastLine = Line;
 454         } while (Line != NULL);
 455
 456         FreeStrBuf(&HeaderName);
 457
 458         return isbogus;
 459 }
 460
 461 void OverrideRequest(ParsedHttpHdrs *Hdr, const char *Line, long len)
 462 {
 463         StrBuf *Buf = NewStrBuf();
 464
 465         if (Hdr->HR.ReqLine != NULL) {
 466                 FlushStrBuf(Hdr->HR.ReqLine);
 467                 StrBufPlain(Hdr->HR.ReqLine, Line, len);
 468         }
 469         else {
 470                 Hdr->HR.ReqLine = NewStrBufPlain(Line, len);
 471         }
 472         ReadHttpSubject(Hdr, Hdr->HR.ReqLine, Buf);
 473
 474         FreeStrBuf(&Buf);
 475 }
 476
 477 /*
 478  * handle one request
 479  *
 480  * This loop gets called once for every HTTP connection made to WebCit.  At
 481  * this entry point we have an HTTP socket with a browser allegedly on the
 482  * other end, but we have not yet bound to a WebCit session.
 483  *
 484  * The job of this function is to locate the correct session and bind to it,
 485  * or create a session if necessary and bind to it, then run the WebCit
 486  * transaction loop.  Afterwards, we unbind from the session.  When this
 487  * function returns, the worker thread is then free to handle another
 488  * transaction.
 489  */
 490 void context_loop(ParsedHttpHdrs *Hdr)
 491 {
 492         int isbogus = 0;
 493         wcsession *TheSession;
 494         struct timeval tx_start;
 495         struct timeval tx_finish;
 496         int session_may_be_reused = 1;
 497         time_t now;
 498
 499         gettimeofday(&tx_start, NULL);          /* start a stopwatch for performance timing */
 500
 501         /*
 502          * Find out what it is that the web browser is asking for
 503          */
 504         isbogus = ReadHTTPRequest(Hdr);
 505
 506         Hdr->HR.dav_depth = 32767; /* TODO: find a general way to have non-0 defaults */
 507
 508         if (!isbogus) {
 509                 isbogus = AnalyseHeaders(Hdr);
 510         }
 511
 512         if (    (isbogus)
 513                 || ((Hdr->HR.Handler != NULL)
 514                 && ((Hdr->HR.Handler->Flags & BOGUS) != 0))
 515         ) {
 516                 wcsession *Bogus;
 517                 Bogus = CreateSession(0, 1, NULL, Hdr, NULL);
 518                 do_404();
 519                 syslog(LOG_WARNING, "HTTP: 404 [%ld.%06ld] %s %s",
 520                         ((tx_finish.tv_sec*1000000 + tx_finish.tv_usec) - (tx_start.tv_sec*1000000 + tx_start.tv_usec)) / 1000000,
 521                         ((tx_finish.tv_sec*1000000 + tx_finish.tv_usec) - (tx_start.tv_sec*1000000 + tx_start.tv_usec)) % 1000000,
 522                         ReqStrs[Hdr->HR.eReqType],
 523                         ChrPtr(Hdr->this_page)
 524                         );
 525                 session_detach_modules(Bogus);
 526                 session_destroy_modules(&Bogus);
 527                 return;
 528         }
 529
 530         if ((Hdr->HR.Handler != NULL) && ((Hdr->HR.Handler->Flags & ISSTATIC) != 0))
 531         {
 532                 wcsession *Static;
 533                 Static = CreateSession(0, 1, NULL, Hdr, NULL);
 534
 535                 Hdr->HR.Handler->F();
 536
 537                 /* How long did this transaction take? */
 538                 gettimeofday(&tx_finish, NULL);
 539
 540                 syslog(LOG_DEBUG, "HTTP: 200 [%ld.%06ld] %s %s",
 541                         ((tx_finish.tv_sec*1000000 + tx_finish.tv_usec) - (tx_start.tv_sec*1000000 + tx_start.tv_usec)) / 1000000,
 542                         ((tx_finish.tv_sec*1000000 + tx_finish.tv_usec) - (tx_start.tv_sec*1000000 + tx_start.tv_usec)) % 1000000,
 543                         ReqStrs[Hdr->HR.eReqType],
 544                         ChrPtr(Hdr->this_page)
 545                 );
 546                 session_detach_modules(Static);
 547                 session_destroy_modules(&Static);
 548                 return;
 549         }
 550
 551         if (Hdr->HR.got_auth == AUTH_BASIC) {
 552                 CheckAuthBasic(Hdr);
 553         }
 554
 555         if (Hdr->HR.got_auth) {
 556                 session_may_be_reused = 0;
 557         }
 558
 559         /*
 560          * See if there's an existing session open with any of:
 561          * - The desired Session ID
 562          * - A matching http-auth username and password
 563          * - An unbound session flagged as reusable
 564          */
 565         TheSession = FindSession(&SessionList, Hdr, &SessionListMutex);
 566
 567         /*
 568          * If there were no qualifying sessions, then create a new one.
 569          */
 570         if ((TheSession == NULL) || (TheSession->killthis != 0)) {
 571                 TheSession = CreateSession(1, 0, &SessionList, Hdr, &SessionListMutex);
 572         }
 573
 574         /*
 575          * Reject transactions which require http-auth, if http-auth was not provided
 576          */
 577         if (    (StrLength(Hdr->c_username) == 0)
 578                 && (!Hdr->HR.DontNeedAuth)
 579                 && (Hdr->HR.Handler != NULL)
 580                 && ((XHTTP_COMMANDS & Hdr->HR.Handler->Flags) == XHTTP_COMMANDS)
 581         ) {
 582                 syslog(LOG_DEBUG, "http-auth required but not provided");
 583                 OverrideRequest(Hdr, HKEY("GET /401 HTTP/1.0"));
 584                 Hdr->HR.prohibit_caching = 1;
 585         }
 586
 587         /*
 588          * A future improvement might be to check the session integrity
 589          * at this point before continuing.
 590          */
 591
 592         /*
 593          * Bind to the session and perform the transaction
 594          */
 595         now = time(NULL);;
 596         CtdlLogResult(pthread_mutex_lock(&TheSession->SessionMutex));
 597         pthread_setspecific(MyConKey, (void *)TheSession);
 598
 599         TheSession->inuse = 1;                          /* mark the session as bound */
 600         TheSession->lastreq = now;                      /* log */
 601         TheSession->Hdr = Hdr;
 602
 603         /*
 604          * If a language was requested via a cookie, select that language now.
 605          */
 606         if (StrLength(Hdr->c_language) > 0) {
 607                 syslog(LOG_DEBUG, "Session cookie requests language '%s'", ChrPtr(Hdr->c_language));
 608                 set_selected_language(ChrPtr(Hdr->c_language));
 609                 go_selected_language();
 610         }
 611
 612         /*
 613          * do the transaction
 614          */
 615         session_attach_modules(TheSession);
 616         session_loop();
 617
 618         /* How long did this transaction take? */
 619         gettimeofday(&tx_finish, NULL);
 620
 621         syslog(LOG_INFO, "HTTP: 200 [%ld.%06ld] %s %s",
 622                 ((tx_finish.tv_sec*1000000 + tx_finish.tv_usec) - (tx_start.tv_sec*1000000 + tx_start.tv_usec)) / 1000000,
 623                 ((tx_finish.tv_sec*1000000 + tx_finish.tv_usec) - (tx_start.tv_sec*1000000 + tx_start.tv_usec)) % 1000000,
 624                 ReqStrs[Hdr->HR.eReqType],
 625                 ChrPtr(Hdr->this_page)
 626         );
 627
 628         session_detach_modules(TheSession);
 629
 630         /* If *this* very transaction did not explicitly specify a session cookie,
 631          * and it did not log in, we want to flag the session as a candidate for
 632          * re-use by the next unbound client that comes along.  This keeps our session
 633          * table from getting bombarded with new sessions when, for example, a web
 634          * spider crawls the site without using cookies.
 635          */
 636         if ((session_may_be_reused) && (!WC->logged_in)) {
 637                 WC->wc_session = 0;                     /* flag as available for re-use */
 638                 TheSession->selected_language = 0;      /* clear any non-default language setting */
 639         }
 640
 641         TheSession->Hdr = NULL;
 642         TheSession->inuse = 0;                                  /* mark the session as unbound */
 643         CtdlLogResult(pthread_mutex_unlock(&TheSession->SessionMutex));
 644 }
 645
 646 void tmplput_nonce(StrBuf *Target, WCTemplputParams *TP)
 647 {
 648         wcsession *WCC = WC;
 649         StrBufAppendPrintf(Target, "%ld",
 650                            (WCC != NULL)? WCC->nonce:0);
 651 }
 652
 653 void tmplput_current_user(StrBuf *Target, WCTemplputParams *TP)
 654 {
 655         StrBufAppendTemplate(Target, TP, WC->wc_fullname, 0);
 656 }
 657
 658 void Header_HandleContentLength(StrBuf *Line, ParsedHttpHdrs *hdr)
 659 {
 660         hdr->HR.ContentLength = StrToi(Line);
 661 }
 662
 663 void Header_HandleContentType(StrBuf *Line, ParsedHttpHdrs *hdr)
 664 {
 665         hdr->HR.ContentType = Line;
 666 }
 667
 668
 669 void Header_HandleHost(StrBuf *Line, ParsedHttpHdrs *hdr)
 670 {
 671         if (hdr->HostHeader != NULL) {
 672                 FreeStrBuf(&hdr->HostHeader);
 673         }
 674         hdr->HostHeader = NewStrBuf();
 675         StrBufAppendPrintf(hdr->HostHeader, "%s://", (is_https ? "https" : "http") );
 676         StrBufAppendBuf(hdr->HostHeader, Line, 0);
 677 }
 678
 679 void Header_HandleXFFHost(StrBuf *Line, ParsedHttpHdrs *hdr)
 680 {
 681         if (!follow_xff) return;
 682
 683         if (hdr->HostHeader != NULL) {
 684                 FreeStrBuf(&hdr->HostHeader);
 685         }
 686
 687         hdr->HostHeader = NewStrBuf();
 688         StrBufAppendPrintf(hdr->HostHeader, "http://"); /* this is naive; do something about it */
 689         StrBufAppendBuf(hdr->HostHeader, Line, 0);
 690 }
 691
 692
 693 void Header_HandleXFF(StrBuf *Line, ParsedHttpHdrs *hdr)
 694 {
 695         hdr->HR.browser_host = Line;
 696
 697         while (StrBufNum_tokens(hdr->HR.browser_host, ',') > 1) {
 698                 StrBufRemove_token(hdr->HR.browser_host, 0, ',');
 699         }
 700         StrBufTrim(hdr->HR.browser_host);
 701 }
 702
 703 void Header_HandleIfModSince(StrBuf *Line, ParsedHttpHdrs *hdr)
 704 {
 705         hdr->HR.if_modified_since = httpdate_to_timestamp(Line);
 706 }
 707
 708 void Header_HandleAcceptEncoding(StrBuf *Line, ParsedHttpHdrs *hdr)
 709 {
 710         /*
 711          * Can we compress?
 712          */
 713         if (strstr(&ChrPtr(Line)[16], "gzip")) {
 714                 hdr->HR.gzip_ok = 1;
 715         }
 716 }
 717 const char *ReqStrs[eNONE] = {
 718         "GET",
 719         "POST",
 720         "OPTIONS",
 721         "PROPFIND",
 722         "PUT",
 723         "DELETE",
 724         "HEAD",
 725         "MOVE",
 726         "COPY",
 727         "REPORT"
 728 };
 729
 730 void
 731 ServerStartModule_CONTEXT
 732 (void)
 733 {
 734         long *v;
 735         HttpReqTypes = NewHash(1, NULL);
 736         HttpHeaderHandler = NewHash(1, NULL);
 737
 738         v = malloc(sizeof(long));
 739         *v = eGET;
 740         Put(HttpReqTypes, HKEY("GET"), v, NULL);
 741
 742         v = malloc(sizeof(long));
 743         *v = ePOST;
 744         Put(HttpReqTypes, HKEY("POST"), v, NULL);
 745
 746         v = malloc(sizeof(long));
 747         *v = eOPTIONS;
 748         Put(HttpReqTypes, HKEY("OPTIONS"), v, NULL);
 749
 750         v = malloc(sizeof(long));
 751         *v = ePROPFIND;
 752         Put(HttpReqTypes, HKEY("PROPFIND"), v, NULL);
 753
 754         v = malloc(sizeof(long));
 755         *v = ePUT;
 756         Put(HttpReqTypes, HKEY("PUT"), v, NULL);
 757
 758         v = malloc(sizeof(long));
 759         *v = eDELETE;
 760         Put(HttpReqTypes, HKEY("DELETE"), v, NULL);
 761
 762         v = malloc(sizeof(long));
 763         *v = eHEAD;
 764         Put(HttpReqTypes, HKEY("HEAD"), v, NULL);
 765
 766         v = malloc(sizeof(long));
 767         *v = eMOVE;
 768         Put(HttpReqTypes, HKEY("MOVE"), v, NULL);
 769
 770         v = malloc(sizeof(long));
 771         *v = eCOPY;
 772         Put(HttpReqTypes, HKEY("COPY"), v, NULL);
 773
 774         v = malloc(sizeof(long));
 775         *v = eREPORT;
 776         Put(HttpReqTypes, HKEY("REPORT"), v, NULL);
 777 }
 778
 779 void
 780 ServerShutdownModule_CONTEXT
 781 (void)
 782 {
 783         DeleteHash(&HttpReqTypes);
 784         DeleteHash(&HttpHeaderHandler);
 785 }
 786
 787 void RegisterHeaderHandler(const char *Name, long Len, Header_Evaluator F)
 788 {
 789         OneHttpHeader *pHdr;
 790         pHdr = (OneHttpHeader*) malloc(sizeof(OneHttpHeader));
 791         memset(pHdr, 0, sizeof(OneHttpHeader));
 792         pHdr->H = F;
 793         Put(HttpHeaderHandler, Name, Len, pHdr, DestroyHttpHeaderHandler);
 794 }
 795
 796
 797 void
 798 InitModule_CONTEXT
 799 (void)
 800 {
 801         RegisterHeaderHandler(HKEY("CONTENT-LENGTH"), Header_HandleContentLength);
 802         RegisterHeaderHandler(HKEY("CONTENT-TYPE"), Header_HandleContentType);
 803         RegisterHeaderHandler(HKEY("X-FORWARDED-HOST"), Header_HandleXFFHost); /* Apache way... */
 804         RegisterHeaderHandler(HKEY("X-REAL-IP"), Header_HandleXFFHost);        /* NGinX way... */
 805         RegisterHeaderHandler(HKEY("HOST"), Header_HandleHost);
 806         RegisterHeaderHandler(HKEY("X-FORWARDED-FOR"), Header_HandleXFF);
 807         RegisterHeaderHandler(HKEY("ACCEPT-ENCODING"), Header_HandleAcceptEncoding);
 808         RegisterHeaderHandler(HKEY("IF-MODIFIED-SINCE"), Header_HandleIfModSince);
 809
 810         RegisterNamespace("CURRENT_USER", 0, 1, tmplput_current_user, NULL, CTX_NONE);
 811         RegisterNamespace("NONCE", 0, 0, tmplput_nonce, NULL, 0);
 812
 813         WebcitAddUrlHandler(HKEY("404"), "", 0, do_404, ANONYMOUS|COOKIEUNNEEDED);
 814 /*
 815  * Look for commonly-found probes of malware such as worms, viruses, trojans, and Microsoft Office.
 816  * Short-circuit these requests so we don't have to send them through the full processing loop.
 817  */
 818         WebcitAddUrlHandler(HKEY("scripts"), "", 0, do_404, ANONYMOUS|BOGUS);           /* /root.exe - Worms and trojans and viruses, oh my! */
 819         WebcitAddUrlHandler(HKEY("c"), "", 0, do_404, ANONYMOUS|BOGUS);         /* /winnt */
 820         WebcitAddUrlHandler(HKEY("MSADC"), "", 0, do_404, ANONYMOUS|BOGUS);
 821         WebcitAddUrlHandler(HKEY("_vti"), "", 0, do_404, ANONYMOUS|BOGUS);              /* Broken Microsoft DAV implementation */
 822         WebcitAddUrlHandler(HKEY("MSOffice"), "", 0, do_404, ANONYMOUS|BOGUS);          /* Stoopid MSOffice thinks everyone is IIS */
 823         WebcitAddUrlHandler(HKEY("nonexistenshit"), "", 0, do_404, ANONYMOUS|BOGUS);    /* Exploit found in the wild January 2009 */
 824 }
 825
 826
 827 void
 828 HttpNewModule_CONTEXT
 829 (ParsedHttpHdrs *httpreq)
 830 {
 831         httpreq->PlainArgs = NewStrBufPlain(NULL, SIZ);
 832         httpreq->this_page = NewStrBufPlain(NULL, SIZ);
 833 }
 834
 835 void
 836 HttpDetachModule_CONTEXT
 837 (ParsedHttpHdrs *httpreq)
 838 {
 839         FlushStrBuf(httpreq->PlainArgs);
 840         FlushStrBuf(httpreq->HostHeader);
 841         FlushStrBuf(httpreq->this_page);
 842         FlushStrBuf(httpreq->PlainArgs);
 843         DeleteHash(&httpreq->HTTPHeaders);
 844         memset(&httpreq->HR, 0, sizeof(HdrRefs));
 845 }
 846
 847 void
 848 HttpDestroyModule_CONTEXT
 849 (ParsedHttpHdrs *httpreq)
 850 {
 851         FreeStrBuf(&httpreq->this_page);
 852         FreeStrBuf(&httpreq->PlainArgs);
 853         FreeStrBuf(&httpreq->this_page);
 854         FreeStrBuf(&httpreq->PlainArgs);
 855         FreeStrBuf(&httpreq->HostHeader);
 856         DeleteHash(&httpreq->HTTPHeaders);
 857
 858 }