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 struct wcsession *SessionList = NULL; /**< our sessions ????*/
  18
  19 pthread_key_t MyConKey;         /**< TSD key for MySession() */
  20
  21
  22 /*
  23  * free the memory used for viewing atachments
  24  */
  25 void free_attachments(struct wcsession *sess) {
  26         struct wc_attachment *att;
  27
  28         while (sess->first_attachment != NULL) {
  29                 att = sess->first_attachment;
  30                 sess->first_attachment = sess->first_attachment->next;
  31                 free(att->data);
  32                 free(att);
  33         }
  34 }
  35
  36
  37 void DestroySession(struct wcsession **sessions_to_kill)
  38 {
  39         close((*sessions_to_kill)->serv_sock);
  40         close((*sessions_to_kill)->chat_sock);
  41 //              if ((*sessions_to_kill)->preferences != NULL) {
  42 //                      free((*sessions_to_kill)->preferences);
  43 //              }
  44         if ((*sessions_to_kill)->cache_fold != NULL) {
  45                 free((*sessions_to_kill)->cache_fold);
  46         }
  47         free_attachments((*sessions_to_kill));
  48         free_march_list((*sessions_to_kill));
  49         DeleteHash(&((*sessions_to_kill)->hash_prefs));
  50         DeleteHash(&((*sessions_to_kill)->IconBarSetttings));
  51         DeleteHash(&((*sessions_to_kill)->ServCfg));
  52         FreeStrBuf(&((*sessions_to_kill)->UrlFragment1));
  53         FreeStrBuf(&((*sessions_to_kill)->UrlFragment2));
  54         FreeStrBuf(&((*sessions_to_kill)->WBuf));
  55         FreeStrBuf(&((*sessions_to_kill)->HBuf));
  56         FreeStrBuf(&((*sessions_to_kill)->CLineBuf));
  57         free((*sessions_to_kill));
  58         (*sessions_to_kill) = NULL;
  59 }
  60
  61 void shutdown_sessions(void)
  62 {
  63         struct wcsession *sptr;
  64
  65         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  66                         sptr->killthis = 1;
  67         }
  68 }
  69
  70 void do_housekeeping(void)
  71 {
  72         struct wcsession *sptr, *ss;
  73         struct wcsession *sessions_to_kill = NULL;
  74         int num_sessions = 0;
  75         static int num_threads = MIN_WORKER_THREADS;
  76
  77         /**
  78          * Lock the session list, moving any candidates for euthanasia into
  79          * a separate list.
  80          */
  81         pthread_mutex_lock(&SessionListMutex);
  82         num_sessions = 0;
  83         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  84                 ++num_sessions;
  85
  86                 /** Kill idle sessions */
  87                 if ((time(NULL) - (sptr->lastreq)) >
  88                    (time_t) WEBCIT_TIMEOUT) {
  89                         sptr->killthis = 1;
  90                 }
  91
  92                 /** Remove sessions flagged for kill */
  93                 if (sptr->killthis) {
  94
  95                         /** remove session from linked list */
  96                         if (sptr == SessionList) {
  97                                 SessionList = SessionList->next;
  98                         }
  99                         else for (ss=SessionList;ss!=NULL;ss=ss->next) {
 100                                 if (ss->next == sptr) {
 101                                         ss->next = ss->next->next;
 102                                 }
 103                         }
 104
 105                         sptr->next = sessions_to_kill;
 106                         sessions_to_kill = sptr;
 107                 }
 108         }
 109         pthread_mutex_unlock(&SessionListMutex);
 110
 111         /**
 112          * Now free up and destroy the culled sessions.
 113          */
 114         while (sessions_to_kill != NULL) {
 115                 lprintf(3, "Destroying session %d\n", sessions_to_kill->wc_session);
 116                 pthread_mutex_lock(&sessions_to_kill->SessionMutex);
 117                 pthread_mutex_unlock(&sessions_to_kill->SessionMutex);
 118                 sptr = sessions_to_kill->next;
 119
 120                 DestroySession(&sessions_to_kill);
 121                 sessions_to_kill = sptr;
 122                 --num_sessions;
 123         }
 124
 125         /**
 126          * If there are more sessions than threads, then we should spawn
 127          * more threads ... up to a predefined maximum.
 128          */
 129         while ( (num_sessions > num_threads)
 130               && (num_threads <= MAX_WORKER_THREADS) ) {
 131                 spawn_another_worker_thread();
 132                 ++num_threads;
 133                 lprintf(3, "There are %d sessions and %d threads active.\n",
 134                         num_sessions, num_threads);
 135         }
 136 }
 137
 138
 139 /**
 140  * \brief Wake up occasionally and clean house
 141  */
 142 void housekeeping_loop(void)
 143 {
 144         while (1) {
 145                 sleeeeeeeeeep(HOUSEKEEPING);
 146                 do_housekeeping();
 147         }
 148 }
 149
 150
 151 /**
 152  * \brief Create a Session id
 153  * Generate a unique WebCit session ID (which is not the same thing as the
 154  * Citadel session ID).
 155  *
 156  * \todo FIXME ... ensure that session number is truly unique
 157  *
 158  */
 159 int GenerateSessionID(void)
 160 {
 161         static int seq = (-1);
 162
 163         if (seq < 0) {
 164                 seq = (int) time(NULL);
 165         }
 166
 167         return ++seq;
 168 }
 169
 170
 171 /*
 172  * Collapse multiple cookies on one line
 173  */
 174 ////int req_gets(int *sock, char *buf, char *hold, size_t hlen)
 175 ////{
 176 ////    int a, b;
 177 ////
 178 ////    if (IsEmptyStr(hold)) {
 179 ////            strcpy(buf, "");
 180 ////            a = client_getln(sock, buf, SIZ);
 181 ////            if (a<1) return(-1);
 182 ////    } else {
 183 ////            safestrncpy(buf, hold, SIZ);
 184 ////    }
 185 ////    strcpy(hold, "");
 186 ////
 187 ////    if (!strncasecmp(buf, "Cookie: ", 8)) {
 188 ////            int len;
 189 ////            len = strlen(buf);
 190 ////            for (a = 0; a < len; ++a)
 191 ////                    if (buf[a] == ';') {
 192 ////                            // we don't refresh len, because of we
 193 ////                            // only exit from here.
 194 ////                            snprintf(hold, hlen, "Cookie: %s", &buf[a + 1]);
 195 ////                            buf[a] = 0;
 196 ////                            b = 8;
 197 ////                            while (isspace(hold[b]))
 198 ////                                    b++;
 199 ////
 200 ////                            memmove(&hold[8], &hold[b], len - b + 1);
 201 ////                            return(0);
 202 ////                    }
 203 ////    }
 204 ////
 205 ////    return(0);
 206 ////}
 207
 208
 209 /*
 210  * Collapse multiple cookies on one line
 211  */
 212 int ReqGetStrBuf(int *sock, StrBuf *Target, StrBuf *buf)
 213 {
 214
 215         return ClientGetLine(sock, Target, buf);
 216 }
 217
 218
 219
 220 /*
 221  * lingering_close() a`la Apache. see
 222  * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
 223  */
 224 int lingering_close(int fd)
 225 {
 226         char buf[SIZ];
 227         int i;
 228         fd_set set;
 229         struct timeval tv, start;
 230
 231         gettimeofday(&start, NULL);
 232         shutdown(fd, 1);
 233         do {
 234                 do {
 235                         gettimeofday(&tv, NULL);
 236                         tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
 237                         tv.tv_usec = start.tv_usec - tv.tv_usec;
 238                         if (tv.tv_usec < 0) {
 239                                 tv.tv_sec--;
 240                                 tv.tv_usec += 1000000;
 241                         }
 242                         FD_ZERO(&set);
 243                         FD_SET(fd, &set);
 244                         i = select(fd + 1, &set, NULL, NULL, &tv);
 245                 } while (i == -1 && errno == EINTR);
 246
 247                 if (i <= 0)
 248                         break;
 249
 250                 i = read(fd, buf, sizeof buf);
 251         } while (i != 0 && (i != -1 || errno == EINTR));
 252
 253         return close(fd);
 254 }
 255
 256
 257
 258 /**
 259  * \brief       sanity requests
 260  *              Check for bogus requests coming from brain-dead Windows boxes.
 261  *
 262  * \param       http_cmd        The HTTP request to check
 263  */
 264 int is_bogus(StrBuf *http_cmd) {
 265         const char *url;
 266         int i, max;
 267
 268         url = ChrPtr(http_cmd);
 269         if (IsEmptyStr(url)) return(1);
 270         ++url;
 271
 272         char *bogus_prefixes[] = {
 273                 "/scripts/root.exe",    /**< Worms and trojans and viruses, oh my! */
 274                 "/c/winnt",
 275                 "/MSADC/",
 276                 "/_vti",                /**< Broken Microsoft DAV implementation */
 277                 "/MSOffice"             /**< Stoopid MSOffice thinks everyone is IIS */
 278         };
 279
 280         max = sizeof(bogus_prefixes) / sizeof(char *);
 281
 282         for (i=0; i<max; ++i) {
 283                 if (!strncasecmp(url, bogus_prefixes[i], strlen(bogus_prefixes[i]))) {
 284                         return(2);
 285                 }
 286         }
 287
 288         return(0);      /* probably ok */
 289 }
 290
 291
 292 const char *nix(void *vptr) {return ChrPtr( (StrBuf*)vptr);}
 293
 294 /**
 295  * \brief handle one request
 296  * This loop gets called once for every HTTP connection made to WebCit.  At
 297  * this entry point we have an HTTP socket with a browser allegedly on the
 298  * other end, but we have not yet bound to a WebCit session.
 299  *
 300  * The job of this function is to locate the correct session and bind to it,
 301  * or create a session if necessary and bind to it, then run the WebCit
 302  * transaction loop.  Afterwards, we unbind from the session.  When this
 303  * function returns, the worker thread is then free to handle another
 304  * transaction.
 305  * \param sock the socket we will put our answer to
 306  */
 307 void context_loop(int *sock)
 308 {
 309         const char *buf;
 310         int desired_session = 0;
 311         int got_cookie = 0;
 312         int gzip_ok = 0;
 313         struct wcsession *TheSession, *sptr;
 314         char httpauth_string[1024];
 315         char httpauth_user[1024];
 316         char httpauth_pass[1024];
 317         char *ptr = NULL;
 318         int session_is_new = 0;
 319         int nLine = 0;
 320         int LineLen;
 321         void *vLine;
 322         StrBuf *Buf, *Line, *LastLine, *HeaderName, *ReqLine, *accept_language, *ReqType, *HTTPVersion;
 323         const char *pch, *pchs, *pche;
 324         HashList *HTTPHeaders;
 325
 326         strcpy(httpauth_string, "");
 327         strcpy(httpauth_user, DEFAULT_HTTPAUTH_USER);
 328         strcpy(httpauth_pass, DEFAULT_HTTPAUTH_PASS);
 329
 330         /**
 331          * Find out what it is that the web browser is asking for
 332          */
 333         HeaderName = NewStrBuf();
 334         Buf = NewStrBuf();
 335         LastLine = NULL;
 336         HTTPHeaders = NewHash(1, NULL);
 337         /**
 338          * Read in the request
 339          */
 340         do {
 341                 nLine ++;
 342                 Line = NewStrBuf();
 343                 if (ReqGetStrBuf(sock, Line, Buf) < 0) return;
 344
 345                 LineLen = StrLength(Line);
 346
 347                 if (nLine == 1) {
 348                         ReqLine = Line;
 349                         continue;
 350                 }
 351                 if (LineLen == 0) {
 352                         FreeStrBuf(&Line);
 353                         continue;
 354                 }
 355
 356                 /** Do we need to Unfold? */
 357                 if ((LastLine != NULL) &&
 358                     (isspace(*ChrPtr(Line)))) {
 359                         pch = pchs = ChrPtr(Line);
 360                         pche = pchs + StrLength(Line);
 361                         while (isspace(pch) && (pch < pche))
 362                                 pch ++;
 363                         StrBufCutLeft(Line, pch - pchs);
 364                         StrBufAppendBuf(LastLine, Line, 0);
 365                         FreeStrBuf(&Line);
 366                         continue;
 367                 }
 368
 369                 StrBufExtract_token(HeaderName, Line, 0, ':');
 370         //// TODO: filter bad chars!
 371
 372                 pchs = ChrPtr(Line);
 373                 pch = pchs + StrLength(HeaderName) + 1;
 374                 pche = pchs + StrLength(Line);
 375                 while (isspace(*pch) && (pch < pche))
 376                         pch ++;
 377                 StrBufCutLeft(Line, pch - pchs);
 378
 379                 StrBufUpCase(HeaderName);
 380                 Put(HTTPHeaders, SKEY(HeaderName), Line, HFreeStrBuf);
 381                 LastLine = Line;
 382         } while (LineLen > 0);
 383         FreeStrBuf(&HeaderName);
 384
 385 ////    dbg_PrintHash(HTTPHeaders, nix, NULL);
 386
 387
 388         /**
 389          * Can we compress?
 390          */
 391         if (GetHash(HTTPHeaders, HKEY("ACCEPT-ENCODING"), &vLine) &&
 392             (vLine != NULL)) {
 393                 buf = ChrPtr((StrBuf*)vLine);
 394                 if (strstr(&buf[16], "gzip")) {
 395                         gzip_ok = 1;
 396                 }
 397         }
 398
 399         /**
 400          * Browser-based sessions use cookies for session authentication
 401          */
 402         if (GetHash(HTTPHeaders, HKEY("COOKIE"), &vLine) &&
 403             (vLine != NULL)) {
 404                 cookie_to_stuff(vLine, &desired_session,
 405                                 NULL, 0, NULL, 0, NULL, 0);
 406                 got_cookie = 1;
 407         }
 408
 409         /**
 410          * GroupDAV-based sessions use HTTP authentication
 411          */
 412         if (GetHash(HTTPHeaders, HKEY("AUTHORIZATION"), &vLine) &&
 413             (vLine != NULL)) {
 414                 Line = (StrBuf*)vLine;
 415                 if (strncasecmp(ChrPtr(Line), "Basic ", 6)) {
 416                         StrBufCutLeft(Line, 6);
 417                         CtdlDecodeBase64(httpauth_string, ChrPtr(Line), StrLength(Line));
 418                         extract_token(httpauth_user, httpauth_string, 0, ':', sizeof httpauth_user);
 419                         extract_token(httpauth_pass, httpauth_string, 1, ':', sizeof httpauth_pass);
 420                 }
 421                 else
 422                         lprintf(1, "Authentication sheme not supported! [%s]\n", ChrPtr(Line));
 423         }
 424
 425         if (GetHash(HTTPHeaders, HKEY("IF-MODIFIED-SINCE"), &vLine) &&
 426             (vLine != NULL)) {
 427                 if_modified_since = httpdate_to_timestamp((StrBuf*)vLine);
 428         }
 429
 430         if (GetHash(HTTPHeaders, HKEY("ACCEPT-LANGUAGE"), &vLine) &&
 431             (vLine != NULL)) {
 432                 accept_language = (StrBuf*) vLine;
 433         }
 434
 435
 436         /**
 437          * If the request is prefixed by "/webcit" then chop that off.  This
 438          * allows a front end web server to forward all /webcit requests to us
 439          * while still using the same web server port for other things.
 440          */
 441
 442         ReqType = NewStrBuf();
 443         HTTPVersion = NewStrBuf();
 444         StrBufExtract_token(HTTPVersion, ReqLine, 2, ' ');
 445         StrBufExtract_token(ReqType, ReqLine, 0, ' ');
 446         StrBufCutLeft(ReqLine, StrLength(ReqType) + 1);
 447         StrBufCutRight(ReqLine, StrLength(HTTPVersion) + 1);
 448
 449         if ((StrLength(ReqLine) > 10) &&
 450             (ptr = strstr(ChrPtr(ReqLine), "/webcit "), /*< Handle "/webcit" */
 451              (ptr != NULL))) {
 452                 StrBufCutLeft(ReqLine, 6);
 453         }
 454
 455         /** Begin parsing the request. */
 456 #ifdef TECH_PREVIEW
 457         if ((strncmp(ChrPtr(ReqLine), "/sslg", 5) != 0) &&
 458             (strncmp(ChrPtr(ReqLine), "/static/", 8) != 0) &&
 459             (strncmp(ChrPtr(ReqLine), "/wholist_section", 16) != 0)) {
 460 #endif
 461                 lprintf(5, "HTTP: %s %s %s\n", ChrPtr(ReqType), ChrPtr(ReqLine), ChrPtr(HTTPVersion));
 462 #ifdef TECH_PREVIEW
 463         }
 464 #endif
 465
 466         /** Check for bogus requests */
 467         if ((StrLength(HTTPVersion) == 0) ||
 468             (StrLength(ReqType) == 0) ||
 469             is_bogus(ReqLine)) {
 470                 StrBufPlain(ReqLine, HKEY("/404 HTTP/1.1"));
 471                 StrBufPlain(ReqType, HKEY("GET"));
 472         }
 473         FreeStrBuf(&HTTPVersion);
 474
 475         /**
 476          * While we're at it, gracefully handle requests for the
 477          * robots.txt and favicon.ico files.
 478          */
 479         if (!strncasecmp(ChrPtr(ReqLine), "/robots.txt", 11)) {
 480                 StrBufPlain(ReqLine,
 481                             HKEY("/static/robots.txt"
 482                                  "?force_close_session=yes HTTP/1.1"));
 483                 StrBufPlain(ReqType, HKEY("GET"));
 484         }
 485         else if (!strncasecmp(ChrPtr(ReqLine), "/favicon.ico", 12)) {
 486                 StrBufPlain(ReqLine, HKEY("/static/favicon.ico"));
 487                 StrBufPlain(ReqType, HKEY("GET"));
 488         }
 489
 490         /**
 491          * These are the URL's which may be executed without a
 492          * session cookie already set.  If it's not one of these,
 493          * force the session to close because cookies are
 494          * probably disabled on the client browser.
 495          */
 496         else if ( (StrLength(ReqLine) > 1 )
 497                 && (strncasecmp(ChrPtr(ReqLine), "/listsub", 8))
 498                 && (strncasecmp(ChrPtr(ReqLine), "/freebusy", 9))
 499                 && (strncasecmp(ChrPtr(ReqLine), "/do_logout", 10))
 500                 && (strncasecmp(ChrPtr(ReqLine), "/groupdav", 9))
 501                 && (strncasecmp(ChrPtr(ReqLine), "/static", 7))
 502                 && (strncasecmp(ChrPtr(ReqLine), "/rss", 4))
 503                 && (strncasecmp(ChrPtr(ReqLine), "/404", 4))
 504                 && (got_cookie == 0)) {
 505                 StrBufPlain(ReqLine,
 506                             HKEY("/static/nocookies.html"
 507                                  "?force_close_session=yes"));
 508         }
 509
 510         /**
 511          * See if there's an existing session open with the desired ID or user/pass
 512          */
 513         TheSession = NULL;
 514
 515         if (TheSession == NULL) {
 516                 pthread_mutex_lock(&SessionListMutex);
 517                 for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
 518
 519                         /** If HTTP-AUTH, look for a session with matching credentials */
 520                         if ( (!IsEmptyStr(httpauth_user))
 521                            &&(!strcasecmp(sptr->httpauth_user, httpauth_user))
 522                            &&(!strcasecmp(sptr->httpauth_pass, httpauth_pass)) ) {
 523                                 TheSession = sptr;
 524                         }
 525
 526                         /** If cookie-session, look for a session with matching session ID */
 527                         if ( (desired_session != 0) && (sptr->wc_session == desired_session)) {
 528                                 TheSession = sptr;
 529                         }
 530
 531                 }
 532                 pthread_mutex_unlock(&SessionListMutex);
 533         }
 534
 535         /**
 536          * Create a new session if we have to
 537          */
 538         if (TheSession == NULL) {
 539                 lprintf(3, "Creating a new session\n");
 540                 TheSession = (struct wcsession *)
 541                         malloc(sizeof(struct wcsession));
 542                 memset(TheSession, 0, sizeof(struct wcsession));
 543                 TheSession->serv_sock = (-1);
 544                 TheSession->chat_sock = (-1);
 545
 546                 /* If we're recreating a session that expired, it's best to give it the same
 547                  * session number that it had before.  The client browser ought to pick up
 548                  * the new session number and start using it, but in some rare situations it
 549                  * doesn't, and that's a Bad Thing because it causes lots of spurious sessions
 550                  * to get created.
 551                  */
 552                 if (desired_session == 0) {
 553                         TheSession->wc_session = GenerateSessionID();
 554                 }
 555                 else {
 556                         TheSession->wc_session = desired_session;
 557                 }
 558
 559                 strcpy(TheSession->httpauth_user, httpauth_user);
 560                 strcpy(TheSession->httpauth_pass, httpauth_pass);
 561                 TheSession->hash_prefs = NewHash(1,NULL);       /* Get a hash table for the user preferences */
 562                 pthread_mutex_init(&TheSession->SessionMutex, NULL);
 563                 pthread_mutex_lock(&SessionListMutex);
 564                 TheSession->urlstrings = NULL;
 565                 TheSession->vars = NULL;
 566                 TheSession->nonce = rand();
 567                 TheSession->WBuf = NULL;
 568                 TheSession->CLineBuf = NewStrBuf();
 569                 TheSession->next = SessionList;
 570                 TheSession->is_mobile = -1;
 571                 SessionList = TheSession;
 572                 pthread_mutex_unlock(&SessionListMutex);
 573                 session_is_new = 1;
 574         }
 575
 576         /*
 577          * A future improvement might be to check the session integrity
 578          * at this point before continuing.
 579          */
 580
 581         /*
 582          * Bind to the session and perform the transaction
 583          */
 584         pthread_mutex_lock(&TheSession->SessionMutex);          /* bind */
 585         pthread_setspecific(MyConKey, (void *)TheSession);
 586
 587         TheSession->urlstrings = NewHash(1,NULL);
 588         TheSession->vars = NewHash(1,NULL);
 589         TheSession->http_sock = *sock;
 590         TheSession->lastreq = time(NULL);                       /* log */
 591         TheSession->gzip_ok = gzip_ok;
 592 #ifdef ENABLE_NLS
 593         if (session_is_new) {
 594                 httplang_to_locale(accept_language);
 595         }
 596         go_selected_language();                                 /* set locale */
 597 #endif
 598         session_loop(HTTPHeaders, ReqLine, ReqType, Buf);                               /* do transaction */
 599 #ifdef ENABLE_NLS
 600         stop_selected_language();                               /* unset locale */
 601 #endif
 602         DeleteHash(&TheSession->urlstrings);
 603         DeleteHash(&TheSession->vars);
 604         FreeStrBuf(&TheSession->WBuf);
 605         FreeStrBuf(&TheSession->HBuf);
 606
 607
 608         pthread_mutex_unlock(&TheSession->SessionMutex);        /* unbind */
 609
 610         /* Free the request buffer */
 611         DeleteHash(&HTTPHeaders);
 612         FreeStrBuf(&ReqLine);
 613         FreeStrBuf(&ReqType);
 614         FreeStrBuf(&Buf);
 615         /*
 616          * Free up any session-local substitution variables which
 617          * were set during this transaction
 618          */
 619
 620
 621 }
 622
 623 void tmpl_nonce(StrBuf *Target, int nArgs, WCTemplateToken *Tokens, void *Context)
 624 {
 625         struct wcsession *WCC = WC;
 626         StrBufAppendPrintf(Target, "%ld",
 627                            (WCC != NULL)? WCC->nonce:0);
 628 }
 629
 630 void
 631 InitModule_CONTEXT
 632 (void)
 633 {
 634         RegisterNamespace("NONCE", 0, 0, tmpl_nonce);
 635 }