webcit/context_loop.c

   1 /*
   2  * $Id$
   3  *
   4  * This is the other half of the webserver.  It handles the task of hooking
   5  * up HTTP requests with the sessions they belong to, using HTTP cookies to
   6  * keep track of things.  If the HTTP request doesn't belong to any currently
   7  * active session, a new session is started.
   8  *
   9  */
  10
  11 #include "webcit.h"
  12 #include "webserver.h"
  13
  14 /* Only one thread may manipulate SessionList at a time... */
  15 pthread_mutex_t SessionListMutex;
  16
  17 wcsession *SessionList = NULL; /**< our sessions ????*/
  18
  19 pthread_key_t MyConKey;         /**< TSD key for MySession() */
  20
  21
  22
  23 void DestroySession(wcsession **sessions_to_kill)
  24 {
  25         close((*sessions_to_kill)->serv_sock);
  26         close((*sessions_to_kill)->chat_sock);
  27 //              if ((*sessions_to_kill)->preferences != NULL) {
  28 //                      free((*sessions_to_kill)->preferences);
  29 //              }
  30         if ((*sessions_to_kill)->cache_fold != NULL) {
  31                 free((*sessions_to_kill)->cache_fold);
  32         }
  33         DeleteHash(&((*sessions_to_kill)->attachments));
  34         free_march_list((*sessions_to_kill));
  35         DeleteHash(&((*sessions_to_kill)->hash_prefs));
  36         DeleteHash(&((*sessions_to_kill)->IconBarSetttings));
  37         DeleteHash(&((*sessions_to_kill)->ServCfg));
  38         FreeStrBuf(&((*sessions_to_kill)->UrlFragment1));
  39         FreeStrBuf(&((*sessions_to_kill)->UrlFragment2));
  40         FreeStrBuf(&((*sessions_to_kill)->UrlFragment3));
  41         FreeStrBuf(&((*sessions_to_kill)->WBuf));
  42         FreeStrBuf(&((*sessions_to_kill)->HBuf));
  43         FreeStrBuf(&((*sessions_to_kill)->CLineBuf));
  44         free((*sessions_to_kill));
  45         (*sessions_to_kill) = NULL;
  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         int num_sessions = 0;
  62         static int num_threads = MIN_WORKER_THREADS;
  63
  64         /**
  65          * Lock the session list, moving any candidates for euthanasia into
  66          * a separate list.
  67          */
  68         pthread_mutex_lock(&SessionListMutex);
  69         num_sessions = 0;
  70         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  71                 ++num_sessions;
  72
  73                 /** Kill idle sessions */
  74                 if ((time(NULL) - (sptr->lastreq)) >
  75                    (time_t) WEBCIT_TIMEOUT) {
  76                         sptr->killthis = 1;
  77                 }
  78
  79                 /** Remove sessions flagged for kill */
  80                 if (sptr->killthis) {
  81
  82                         /** remove session from linked list */
  83                         if (sptr == SessionList) {
  84                                 SessionList = SessionList->next;
  85                         }
  86                         else for (ss=SessionList;ss!=NULL;ss=ss->next) {
  87                                 if (ss->next == sptr) {
  88                                         ss->next = ss->next->next;
  89                                 }
  90                         }
  91
  92                         sptr->next = sessions_to_kill;
  93                         sessions_to_kill = sptr;
  94                 }
  95         }
  96         pthread_mutex_unlock(&SessionListMutex);
  97
  98         /**
  99          * Now free up and destroy the culled sessions.
 100          */
 101         while (sessions_to_kill != NULL) {
 102                 lprintf(3, "Destroying session %d\n", sessions_to_kill->wc_session);
 103                 pthread_mutex_lock(&sessions_to_kill->SessionMutex);
 104                 pthread_mutex_unlock(&sessions_to_kill->SessionMutex);
 105                 sptr = sessions_to_kill->next;
 106
 107                 DestroySession(&sessions_to_kill);
 108                 sessions_to_kill = sptr;
 109                 --num_sessions;
 110         }
 111
 112         /**
 113          * If there are more sessions than threads, then we should spawn
 114          * more threads ... up to a predefined maximum.
 115          */
 116         while ( (num_sessions > num_threads)
 117               && (num_threads <= MAX_WORKER_THREADS) ) {
 118                 spawn_another_worker_thread();
 119                 ++num_threads;
 120                 lprintf(3, "There are %d sessions and %d threads active.\n",
 121                         num_sessions, num_threads);
 122         }
 123 }
 124
 125
 126 /**
 127  * \brief Wake up occasionally and clean house
 128  */
 129 void housekeeping_loop(void)
 130 {
 131         while (1) {
 132                 sleeeeeeeeeep(HOUSEKEEPING);
 133                 do_housekeeping();
 134         }
 135 }
 136
 137
 138 /**
 139  * \brief Create a Session id
 140  * Generate a unique WebCit session ID (which is not the same thing as the
 141  * Citadel session ID).
 142  *
 143  * \todo FIXME ... ensure that session number is truly unique
 144  *
 145  */
 146 int GenerateSessionID(void)
 147 {
 148         static int seq = (-1);
 149
 150         if (seq < 0) {
 151                 seq = (int) time(NULL);
 152         }
 153
 154         return ++seq;
 155 }
 156
 157
 158 /*
 159  * Collapse multiple cookies on one line
 160  */
 161 ////int req_gets(int *sock, char *buf, char *hold, size_t hlen)
 162 ////{
 163 ////    int a, b;
 164 ////
 165 ////    if (IsEmptyStr(hold)) {
 166 ////            strcpy(buf, "");
 167 ////            a = client_getln(sock, buf, SIZ);
 168 ////            if (a<1) return(-1);
 169 ////    } else {
 170 ////            safestrncpy(buf, hold, SIZ);
 171 ////    }
 172 ////    strcpy(hold, "");
 173 ////
 174 ////    if (!strncasecmp(buf, "Cookie: ", 8)) {
 175 ////            int len;
 176 ////            len = strlen(buf);
 177 ////            for (a = 0; a < len; ++a)
 178 ////                    if (buf[a] == ';') {
 179 ////                            // we don't refresh len, because of we
 180 ////                            // only exit from here.
 181 ////                            snprintf(hold, hlen, "Cookie: %s", &buf[a + 1]);
 182 ////                            buf[a] = 0;
 183 ////                            b = 8;
 184 ////                            while (isspace(hold[b]))
 185 ////                                    b++;
 186 ////
 187 ////                            memmove(&hold[8], &hold[b], len - b + 1);
 188 ////                            return(0);
 189 ////                    }
 190 ////    }
 191 ////
 192 ////    return(0);
 193 ////}
 194
 195
 196 /*
 197  * Collapse multiple cookies on one line
 198  */
 199 int ReqGetStrBuf(int *sock, StrBuf *Target, StrBuf *buf)
 200 {
 201
 202         return ClientGetLine(sock, Target, buf);
 203 }
 204
 205
 206
 207 /*
 208  * lingering_close() a`la Apache. see
 209  * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
 210  */
 211 int lingering_close(int fd)
 212 {
 213         char buf[SIZ];
 214         int i;
 215         fd_set set;
 216         struct timeval tv, start;
 217
 218         gettimeofday(&start, NULL);
 219         shutdown(fd, 1);
 220         do {
 221                 do {
 222                         gettimeofday(&tv, NULL);
 223                         tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
 224                         tv.tv_usec = start.tv_usec - tv.tv_usec;
 225                         if (tv.tv_usec < 0) {
 226                                 tv.tv_sec--;
 227                                 tv.tv_usec += 1000000;
 228                         }
 229                         FD_ZERO(&set);
 230                         FD_SET(fd, &set);
 231                         i = select(fd + 1, &set, NULL, NULL, &tv);
 232                 } while (i == -1 && errno == EINTR);
 233
 234                 if (i <= 0)
 235                         break;
 236
 237                 i = read(fd, buf, sizeof buf);
 238         } while (i != 0 && (i != -1 || errno == EINTR));
 239
 240         return close(fd);
 241 }
 242
 243
 244
 245 /**
 246  * \brief       sanity requests
 247  *              Check for bogus requests coming from brain-dead Windows boxes.
 248  *
 249  * \param       http_cmd        The HTTP request to check
 250  */
 251 int is_bogus(StrBuf *http_cmd) {
 252         const char *url;
 253         int i, max;
 254
 255         url = ChrPtr(http_cmd);
 256         if (IsEmptyStr(url)) return(1);
 257         ++url;
 258
 259         char *bogus_prefixes[] = {
 260                 "/scripts/root.exe",    /**< Worms and trojans and viruses, oh my! */
 261                 "/c/winnt",
 262                 "/MSADC/",
 263                 "/_vti",                /**< Broken Microsoft DAV implementation */
 264                 "/MSOffice"             /**< Stoopid MSOffice thinks everyone is IIS */
 265         };
 266
 267         max = sizeof(bogus_prefixes) / sizeof(char *);
 268
 269         for (i=0; i<max; ++i) {
 270                 if (!strncasecmp(url, bogus_prefixes[i], strlen(bogus_prefixes[i]))) {
 271                         return(2);
 272                 }
 273         }
 274
 275         return(0);      /* probably ok */
 276 }
 277
 278
 279 const char *nix(void *vptr) {return ChrPtr( (StrBuf*)vptr);}
 280
 281 /**
 282  * \brief handle one request
 283  * This loop gets called once for every HTTP connection made to WebCit.  At
 284  * this entry point we have an HTTP socket with a browser allegedly on the
 285  * other end, but we have not yet bound to a WebCit session.
 286  *
 287  * The job of this function is to locate the correct session and bind to it,
 288  * or create a session if necessary and bind to it, then run the WebCit
 289  * transaction loop.  Afterwards, we unbind from the session.  When this
 290  * function returns, the worker thread is then free to handle another
 291  * transaction.
 292  * \param sock the socket we will put our answer to
 293  */
 294 void context_loop(int *sock)
 295 {
 296         const char *buf;
 297         int desired_session = 0;
 298         int got_cookie = 0;
 299         int gzip_ok = 0;
 300         wcsession *TheSession, *sptr;
 301         char httpauth_string[1024];
 302         char httpauth_user[1024];
 303         char httpauth_pass[1024];
 304         char *ptr = NULL;
 305         int session_is_new = 0;
 306         int nLine = 0;
 307         int LineLen;
 308         void *vLine;
 309         StrBuf *Buf, *Line, *LastLine, *HeaderName, *ReqLine, *ReqType, *HTTPVersion;
 310         StrBuf *accept_language = NULL;
 311         const char *pch, *pchs, *pche;
 312         HashList *HTTPHeaders;
 313
 314         strcpy(httpauth_string, "");
 315         strcpy(httpauth_user, DEFAULT_HTTPAUTH_USER);
 316         strcpy(httpauth_pass, DEFAULT_HTTPAUTH_PASS);
 317
 318         /**
 319          * Find out what it is that the web browser is asking for
 320          */
 321         HeaderName = NewStrBuf();
 322         Buf = NewStrBuf();
 323         LastLine = NULL;
 324         HTTPHeaders = NewHash(1, NULL);
 325         /**
 326          * Read in the request
 327          */
 328         do {
 329                 nLine ++;
 330                 Line = NewStrBuf();
 331                 if (ReqGetStrBuf(sock, Line, Buf) < 0) return;
 332
 333                 LineLen = StrLength(Line);
 334
 335                 if (nLine == 1) {
 336                         ReqLine = Line;
 337                         continue;
 338                 }
 339                 if (LineLen == 0) {
 340                         FreeStrBuf(&Line);
 341                         continue;
 342                 }
 343
 344                 /** Do we need to Unfold? */
 345                 if ((LastLine != NULL) &&
 346                     (isspace(*ChrPtr(Line)))) {
 347                         pch = pchs = ChrPtr(Line);
 348                         pche = pchs + StrLength(Line);
 349                         while (isspace(*pch) && (pch < pche))
 350                                 pch ++;
 351                         StrBufCutLeft(Line, pch - pchs);
 352                         StrBufAppendBuf(LastLine, Line, 0);
 353                         FreeStrBuf(&Line);
 354                         continue;
 355                 }
 356
 357                 StrBufExtract_token(HeaderName, Line, 0, ':');
 358         //// TODO: filter bad chars!
 359
 360                 pchs = ChrPtr(Line);
 361                 pch = pchs + StrLength(HeaderName) + 1;
 362                 pche = pchs + StrLength(Line);
 363                 while (isspace(*pch) && (pch < pche))
 364                         pch ++;
 365                 StrBufCutLeft(Line, pch - pchs);
 366
 367                 StrBufUpCase(HeaderName);
 368                 Put(HTTPHeaders, SKEY(HeaderName), Line, HFreeStrBuf);
 369                 LastLine = Line;
 370         } while (LineLen > 0);
 371         FreeStrBuf(&HeaderName);
 372
 373 ////    dbg_PrintHash(HTTPHeaders, nix, NULL);
 374
 375
 376         /**
 377          * Can we compress?
 378          */
 379         if (GetHash(HTTPHeaders, HKEY("ACCEPT-ENCODING"), &vLine) &&
 380             (vLine != NULL)) {
 381                 buf = ChrPtr((StrBuf*)vLine);
 382                 if (strstr(&buf[16], "gzip")) {
 383                         gzip_ok = 1;
 384                 }
 385         }
 386
 387         /**
 388          * Browser-based sessions use cookies for session
 389
 390 authentication
 391          */
 392         if (GetHash(HTTPHeaders, HKEY("COOKIE"), &vLine) &&
 393             (vLine != NULL)) {
 394                 cookie_to_stuff(vLine, &desired_session,
 395                                 NULL, 0, NULL, 0, NULL, 0);
 396                 got_cookie = 1;
 397         }
 398
 399         /**
 400          * GroupDAV-based sessions use HTTP authentication
 401          */
 402         if (GetHash(HTTPHeaders, HKEY("AUTHORIZATION"), &vLine) &&
 403             (vLine != NULL)) {
 404                 Line = (StrBuf*)vLine;
 405                 if (strncasecmp(ChrPtr(Line), "Basic", 5) == 0) {
 406                         StrBufCutLeft(Line, 6);
 407                         CtdlDecodeBase64(httpauth_string, ChrPtr(Line), StrLength(Line));
 408                         extract_token(httpauth_user, httpauth_string, 0, ':', sizeof httpauth_user);
 409                         extract_token(httpauth_pass, httpauth_string, 1, ':', sizeof httpauth_pass);
 410                 }
 411                 else
 412                         lprintf(1, "Authentication scheme not supported! [%s]\n", ChrPtr(Line));
 413         }
 414
 415         if (GetHash(HTTPHeaders, HKEY("IF-MODIFIED-SINCE"), &vLine) &&
 416             (vLine != NULL)) {
 417                 if_modified_since = httpdate_to_timestamp((StrBuf*)vLine);
 418         }
 419
 420         if (GetHash(HTTPHeaders, HKEY("ACCEPT-LANGUAGE"), &vLine) &&
 421             (vLine != NULL)) {
 422                 accept_language = (StrBuf*) vLine;
 423         }
 424
 425
 426         /**
 427          * If the request is prefixed by "/webcit" then chop that off.  This
 428          * allows a front end web server to forward all /webcit requests to us
 429          * while still using the same web server port for other things.
 430          */
 431
 432         ReqType = NewStrBuf();
 433         HTTPVersion = NewStrBuf();
 434         StrBufExtract_token(HTTPVersion, ReqLine, 2, ' ');
 435         StrBufExtract_token(ReqType, ReqLine, 0, ' ');
 436         StrBufCutLeft(ReqLine, StrLength(ReqType) + 1);
 437         StrBufCutRight(ReqLine, StrLength(HTTPVersion) + 1);
 438
 439         if ((follow_xff == 1) && (StrLength(ReqLine) >= 8) &&
 440             (ptr = strstr(ChrPtr(ReqLine), "/webcit/"), /*< Handle "/webcit/" */
 441              (ptr != NULL))) {
 442                 StrBufCutLeft(ReqLine, 7);
 443         }
 444
 445         /** Begin parsing the request. */
 446 #ifdef TECH_PREVIEW
 447         if ((strncmp(ChrPtr(ReqLine), "/sslg", 5) != 0) &&
 448             (strncmp(ChrPtr(ReqLine), "/static/", 8) != 0) &&
 449             (strncmp(ChrPtr(ReqLine), "/tiny_mce/", 10) != 0) &&
 450             (strncmp(ChrPtr(ReqLine), "/wholist_section", 16) != 0) &&
 451             (strstr(ChrPtr(ReqLine), "wholist_section") == NULL)) {
 452 #endif
 453                 lprintf(5, "HTTP: %s %s %s\n", ChrPtr(ReqType), ChrPtr(ReqLine), ChrPtr(HTTPVersion));
 454 #ifdef TECH_PREVIEW
 455         }
 456 #endif
 457
 458         /** Check for bogus requests */
 459         if ((StrLength(HTTPVersion) == 0) ||
 460             (StrLength(ReqType) == 0) ||
 461             is_bogus(ReqLine)) {
 462                 StrBufPlain(ReqLine, HKEY("/404 HTTP/1.1"));
 463                 StrBufPlain(ReqType, HKEY("GET"));
 464         }
 465         FreeStrBuf(&HTTPVersion);
 466
 467         /**
 468          * While we're at it, gracefully handle requests for the
 469          * robots.txt and favicon.ico files.
 470          */
 471         if (!strncasecmp(ChrPtr(ReqLine), "/robots.txt", 11)) {
 472                 StrBufPlain(ReqLine,
 473                             HKEY("/static/robots.txt"
 474                                  "?force_close_session=yes HTTP/1.1"));
 475                 StrBufPlain(ReqType, HKEY("GET"));
 476         }
 477         else if (!strncasecmp(ChrPtr(ReqLine), "/favicon.ico", 12)) {
 478                 StrBufPlain(ReqLine, HKEY("/static/favicon.ico"));
 479                 StrBufPlain(ReqType, HKEY("GET"));
 480         }
 481
 482         /**
 483          * These are the URL's which may be executed without a
 484          * session cookie already set.  If it's not one of these,
 485          * force the session to close because cookies are
 486          * probably disabled on the client browser.
 487          */
 488         else if ( (StrLength(ReqLine) > 1 )
 489                 && (strncasecmp(ChrPtr(ReqLine), "/listsub", 8))
 490                 && (strncasecmp(ChrPtr(ReqLine), "/freebusy", 9))
 491                 && (strncasecmp(ChrPtr(ReqLine), "/do_logout", 10))
 492                 && (strncasecmp(ChrPtr(ReqLine), "/groupdav", 9))
 493                 && (strncasecmp(ChrPtr(ReqLine), "/static", 7))
 494                 && (strncasecmp(ChrPtr(ReqLine), "/rss", 4))
 495                 && (strncasecmp(ChrPtr(ReqLine), "/404", 4))
 496                 && (got_cookie == 0)) {
 497                 StrBufPlain(ReqLine,
 498                             HKEY("/static/nocookies.html"
 499                                  "?force_close_session=yes"));
 500         }
 501
 502         /**
 503          * See if there's an existing session open with the desired ID or user/pass
 504          */
 505         TheSession = NULL;
 506
 507         if (TheSession == NULL) {
 508                 pthread_mutex_lock(&SessionListMutex);
 509                 for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
 510
 511                         /** If HTTP-AUTH, look for a session with matching credentials */
 512                         if ( (!IsEmptyStr(httpauth_user))
 513                            &&(!strcasecmp(sptr->httpauth_user, httpauth_user))
 514                            &&(!strcasecmp(sptr->httpauth_pass, httpauth_pass)) ) {
 515                                 TheSession = sptr;
 516                         }
 517
 518                         /** If cookie-session, look for a session with matching session ID */
 519                         if ( (desired_session != 0) && (sptr->wc_session == desired_session)) {
 520                                 TheSession = sptr;
 521                         }
 522
 523                 }
 524                 pthread_mutex_unlock(&SessionListMutex);
 525         }
 526
 527         /**
 528          * Create a new session if we have to
 529          */
 530         if (TheSession == NULL) {
 531                 lprintf(3, "Creating a new session\n");
 532                 TheSession = (wcsession *)
 533                         malloc(sizeof(wcsession));
 534                 memset(TheSession, 0, sizeof(wcsession));
 535                 TheSession->serv_sock = (-1);
 536                 TheSession->chat_sock = (-1);
 537
 538                 /* If we're recreating a session that expired, it's best to give it the same
 539                  * session number that it had before.  The client browser ought to pick up
 540                  * the new session number and start using it, but in some rare situations it
 541                  * doesn't, and that's a Bad Thing because it causes lots of spurious sessions
 542                  * to get created.
 543                  */
 544                 if (desired_session == 0) {
 545                         TheSession->wc_session = GenerateSessionID();
 546                 }
 547                 else {
 548                         TheSession->wc_session = desired_session;
 549                 }
 550
 551                 strcpy(TheSession->httpauth_user, httpauth_user);
 552                 strcpy(TheSession->httpauth_pass, httpauth_pass);
 553                 TheSession->hash_prefs = NewHash(1,NULL);       /* Get a hash table for the user preferences */
 554                 pthread_mutex_init(&TheSession->SessionMutex, NULL);
 555                 pthread_mutex_lock(&SessionListMutex);
 556                 TheSession->urlstrings = NULL;
 557                 TheSession->vars = NULL;
 558                 TheSession->nonce = rand();
 559                 TheSession->WBuf = NULL;
 560                 TheSession->CLineBuf = NewStrBuf();
 561                 TheSession->next = SessionList;
 562                 TheSession->is_mobile = -1;
 563                 SessionList = TheSession;
 564                 pthread_mutex_unlock(&SessionListMutex);
 565                 session_is_new = 1;
 566         }
 567
 568         /*
 569          * A future improvement might be to check the session integrity
 570          * at this point before continuing.
 571          */
 572
 573         /*
 574          * Bind to the session and perform the transaction
 575          */
 576         pthread_mutex_lock(&TheSession->SessionMutex);          /* bind */
 577         pthread_setspecific(MyConKey, (void *)TheSession);
 578
 579         TheSession->urlstrings = NewHash(1,NULL);
 580         TheSession->vars = NewHash(1,NULL);
 581         TheSession->http_sock = *sock;
 582         TheSession->lastreq = time(NULL);                       /* log */
 583         TheSession->gzip_ok = gzip_ok;
 584 #ifdef ENABLE_NLS
 585         if (session_is_new) {
 586                 httplang_to_locale(accept_language);
 587         }
 588         go_selected_language();                                 /* set locale */
 589 #endif
 590         session_loop(HTTPHeaders, ReqLine, ReqType, Buf);                               /* do transaction */
 591 #ifdef ENABLE_NLS
 592         stop_selected_language();                               /* unset locale */
 593 #endif
 594         DeleteHash(&TheSession->summ);
 595         DeleteHash(&TheSession->urlstrings);
 596         DeleteHash(&TheSession->vars);
 597         FreeStrBuf(&TheSession->WBuf);
 598         FreeStrBuf(&TheSession->HBuf);
 599
 600
 601         pthread_mutex_unlock(&TheSession->SessionMutex);        /* unbind */
 602
 603         /* Free the request buffer */
 604         DeleteHash(&HTTPHeaders);
 605         FreeStrBuf(&ReqLine);
 606         FreeStrBuf(&ReqType);
 607         FreeStrBuf(&Buf);
 608         /*
 609          * Free up any session-local substitution variables which
 610          * were set during this transaction
 611          */
 612
 613
 614 }
 615
 616 void tmpl_nonce(StrBuf *Target, int nArgs, WCTemplateToken *Tokens, void *Context, int ContextType)
 617 {
 618         wcsession *WCC = WC;
 619         StrBufAppendPrintf(Target, "%ld",
 620                            (WCC != NULL)? WCC->nonce:0);
 621 }
 622
 623 void
 624 InitModule_CONTEXT
 625 (void)
 626 {
 627         RegisterNamespace("NONCE", 0, 0, tmpl_nonce, 0);
 628 }