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 shutdown_sessions(void)
  38 {
  39         struct wcsession *sptr;
  40
  41         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  42                         sptr->killthis = 1;
  43         }
  44 }
  45
  46 void do_housekeeping(void)
  47 {
  48         struct wcsession *sptr, *ss;
  49         struct wcsession *sessions_to_kill = NULL;
  50         int num_sessions = 0;
  51         static int num_threads = MIN_WORKER_THREADS;
  52
  53         /**
  54          * Lock the session list, moving any candidates for euthanasia into
  55          * a separate list.
  56          */
  57         pthread_mutex_lock(&SessionListMutex);
  58         num_sessions = 0;
  59         for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
  60                 ++num_sessions;
  61
  62                 /** Kill idle sessions */
  63                 if ((time(NULL) - (sptr->lastreq)) >
  64                    (time_t) WEBCIT_TIMEOUT) {
  65                         sptr->killthis = 1;
  66                 }
  67
  68                 /** Remove sessions flagged for kill */
  69                 if (sptr->killthis) {
  70
  71                         /** remove session from linked list */
  72                         if (sptr == SessionList) {
  73                                 SessionList = SessionList->next;
  74                         }
  75                         else for (ss=SessionList;ss!=NULL;ss=ss->next) {
  76                                 if (ss->next == sptr) {
  77                                         ss->next = ss->next->next;
  78                                 }
  79                         }
  80
  81                         sptr->next = sessions_to_kill;
  82                         sessions_to_kill = sptr;
  83                 }
  84         }
  85         pthread_mutex_unlock(&SessionListMutex);
  86
  87         /**
  88          * Now free up and destroy the culled sessions.
  89          */
  90         while (sessions_to_kill != NULL) {
  91                 lprintf(3, "Destroying session %d\n", sessions_to_kill->wc_session);
  92                 pthread_mutex_lock(&sessions_to_kill->SessionMutex);
  93                 close(sessions_to_kill->serv_sock);
  94                 close(sessions_to_kill->chat_sock);
  95 //              if (sessions_to_kill->preferences != NULL) {
  96 //                      free(sessions_to_kill->preferences);
  97 //              }
  98                 if (sessions_to_kill->cache_fold != NULL) {
  99                         free(sessions_to_kill->cache_fold);
 100                 }
 101                 free_attachments(sessions_to_kill);
 102                 free_march_list(sessions_to_kill);
 103                 DeleteHash(&(sessions_to_kill->hash_prefs));
 104                 DeleteHash(&(sessions_to_kill->IconBarSetttings));
 105                 FreeStrBuf(&(sessions_to_kill->UrlFragment1));
 106                 FreeStrBuf(&(sessions_to_kill->UrlFragment2));
 107                 FreeStrBuf(&(sessions_to_kill->WBuf));
 108                 FreeStrBuf(&(sessions_to_kill->HBuf));
 109
 110                 pthread_mutex_unlock(&sessions_to_kill->SessionMutex);
 111                 sptr = sessions_to_kill->next;
 112                 free(sessions_to_kill);
 113                 sessions_to_kill = sptr;
 114                 --num_sessions;
 115         }
 116
 117         /**
 118          * If there are more sessions than threads, then we should spawn
 119          * more threads ... up to a predefined maximum.
 120          */
 121         while ( (num_sessions > num_threads)
 122               && (num_threads <= MAX_WORKER_THREADS) ) {
 123                 spawn_another_worker_thread();
 124                 ++num_threads;
 125                 lprintf(3, "There are %d sessions and %d threads active.\n",
 126                         num_sessions, num_threads);
 127         }
 128 }
 129
 130
 131 /**
 132  * \brief Wake up occasionally and clean house
 133  */
 134 void housekeeping_loop(void)
 135 {
 136         while (1) {
 137                 sleeeeeeeeeep(HOUSEKEEPING);
 138                 do_housekeeping();
 139         }
 140 }
 141
 142
 143 /**
 144  * \brief Create a Session id
 145  * Generate a unique WebCit session ID (which is not the same thing as the
 146  * Citadel session ID).
 147  *
 148  * \todo FIXME ... ensure that session number is truly unique
 149  *
 150  */
 151 int GenerateSessionID(void)
 152 {
 153         static int seq = (-1);
 154
 155         if (seq < 0) {
 156                 seq = (int) time(NULL);
 157         }
 158
 159         return ++seq;
 160 }
 161
 162
 163 /*
 164  * Collapse multiple cookies on one line
 165  */
 166 int req_gets(int sock, char *buf, char *hold, size_t hlen)
 167 {
 168         int a, b;
 169
 170         if (IsEmptyStr(hold)) {
 171                 strcpy(buf, "");
 172                 a = client_getln(sock, buf, SIZ);
 173                 if (a<1) return(-1);
 174         } else {
 175                 safestrncpy(buf, hold, SIZ);
 176         }
 177         strcpy(hold, "");
 178
 179         if (!strncasecmp(buf, "Cookie: ", 8)) {
 180                 int len;
 181                 len = strlen(buf);
 182                 for (a = 0; a < len; ++a)
 183                         if (buf[a] == ';') {
 184                                 // we don't refresh len, because of we
 185                                 // only exit from here.
 186                                 snprintf(hold, hlen, "Cookie: %s", &buf[a + 1]);
 187                                 buf[a] = 0;
 188                                 b = 8;
 189                                 while (isspace(hold[b]))
 190                                         b++;
 191
 192                                 memmove(&hold[8], &hold[b], len - b + 1);
 193                                 return(0);
 194                         }
 195         }
 196
 197         return(0);
 198 }
 199
 200 /*
 201  * lingering_close() a`la Apache. see
 202  * http://www.apache.org/docs/misc/fin_wait_2.html for rationale
 203  */
 204 int lingering_close(int fd)
 205 {
 206         char buf[SIZ];
 207         int i;
 208         fd_set set;
 209         struct timeval tv, start;
 210
 211         gettimeofday(&start, NULL);
 212         shutdown(fd, 1);
 213         do {
 214                 do {
 215                         gettimeofday(&tv, NULL);
 216                         tv.tv_sec = SLEEPING - (tv.tv_sec - start.tv_sec);
 217                         tv.tv_usec = start.tv_usec - tv.tv_usec;
 218                         if (tv.tv_usec < 0) {
 219                                 tv.tv_sec--;
 220                                 tv.tv_usec += 1000000;
 221                         }
 222                         FD_ZERO(&set);
 223                         FD_SET(fd, &set);
 224                         i = select(fd + 1, &set, NULL, NULL, &tv);
 225                 } while (i == -1 && errno == EINTR);
 226
 227                 if (i <= 0)
 228                         break;
 229
 230                 i = read(fd, buf, sizeof buf);
 231         } while (i != 0 && (i != -1 || errno == EINTR));
 232
 233         return close(fd);
 234 }
 235
 236
 237
 238 /**
 239  * \brief       sanity requests
 240  *              Check for bogus requests coming from brain-dead Windows boxes.
 241  *
 242  * \param       http_cmd        The HTTP request to check
 243  */
 244 int is_bogus(char *http_cmd) {
 245         char *url;
 246         int i, max;
 247
 248         url = strstr(http_cmd, " ");
 249         if (url == NULL) return(1);
 250         ++url;
 251
 252         char *bogus_prefixes[] = {
 253                 "/scripts/root.exe",    /**< Worms and trojans and viruses, oh my! */
 254                 "/c/winnt",
 255                 "/MSADC/",
 256                 "/_vti",                /**< Broken Microsoft DAV implementation */
 257                 "/MSOffice"             /**< Stoopid MSOffice thinks everyone is IIS */
 258         };
 259
 260         max = sizeof(bogus_prefixes) / sizeof(char *);
 261
 262         for (i=0; i<max; ++i) {
 263                 if (!strncasecmp(url, bogus_prefixes[i], strlen(bogus_prefixes[i]))) {
 264                         return(2);
 265                 }
 266         }
 267
 268         return(0);      /* probably ok */
 269 }
 270
 271
 272
 273 /**
 274  * \brief handle one request
 275  * This loop gets called once for every HTTP connection made to WebCit.  At
 276  * this entry point we have an HTTP socket with a browser allegedly on the
 277  * other end, but we have not yet bound to a WebCit session.
 278  *
 279  * The job of this function is to locate the correct session and bind to it,
 280  * or create a session if necessary and bind to it, then run the WebCit
 281  * transaction loop.  Afterwards, we unbind from the session.  When this
 282  * function returns, the worker thread is then free to handle another
 283  * transaction.
 284  * \param sock the socket we will put our answer to
 285  */
 286 void context_loop(int sock)
 287 {
 288         struct httprequest *req = NULL;
 289         struct httprequest *last = NULL;
 290         struct httprequest *hptr;
 291         char buf[SIZ], hold[SIZ];
 292         int desired_session = 0;
 293         int got_cookie = 0;
 294         int gzip_ok = 0;
 295         struct wcsession *TheSession, *sptr;
 296         char httpauth_string[1024];
 297         char httpauth_user[1024];
 298         char httpauth_pass[1024];
 299         char accept_language[256];
 300         char *ptr = NULL;
 301         int session_is_new = 0;
 302
 303         strcpy(httpauth_string, "");
 304         strcpy(httpauth_user, DEFAULT_HTTPAUTH_USER);
 305         strcpy(httpauth_pass, DEFAULT_HTTPAUTH_PASS);
 306
 307         /**
 308          * Find out what it is that the web browser is asking for
 309          */
 310         memset(hold, 0, sizeof(hold));
 311         do {
 312                 if (req_gets(sock, buf, hold, SIZ) < 0) return;
 313
 314                 /**
 315                  * Can we compress?
 316                  */
 317                 if (!strncasecmp(buf, "Accept-encoding:", 16)) {
 318                         if (strstr(&buf[16], "gzip")) {
 319                                 gzip_ok = 1;
 320                         }
 321                 }
 322
 323                 /**
 324                  * Browser-based sessions use cookies for session authentication
 325                  */
 326                 if (!strncasecmp(buf, "Cookie: webcit=", 15)) {
 327                         cookie_to_stuff(&buf[15], &desired_session,
 328                                 NULL, 0, NULL, 0, NULL, 0);
 329                         got_cookie = 1;
 330                 }
 331
 332                 /**
 333                  * GroupDAV-based sessions use HTTP authentication
 334                  */
 335                 if (!strncasecmp(buf, "Authorization: Basic ", 21)) {
 336                         CtdlDecodeBase64(httpauth_string, &buf[21], strlen(&buf[21]));
 337                         extract_token(httpauth_user, httpauth_string, 0, ':', sizeof httpauth_user);
 338                         extract_token(httpauth_pass, httpauth_string, 1, ':', sizeof httpauth_pass);
 339                 }
 340
 341                 if (!strncasecmp(buf, "If-Modified-Since: ", 19)) {
 342                         if_modified_since = httpdate_to_timestamp(&buf[19]);
 343                 }
 344
 345                 if (!strncasecmp(buf, "Accept-Language: ", 17)) {
 346                         safestrncpy(accept_language, &buf[17], sizeof accept_language);
 347                 }
 348
 349                 /**
 350                  * Read in the request
 351                  */
 352                 hptr = (struct httprequest *)
 353                         malloc(sizeof(struct httprequest));
 354                 if (req == NULL)
 355                         req = hptr;
 356                 else
 357                         last->next = hptr;
 358                 hptr->next = NULL;
 359                 last = hptr;
 360
 361                 safestrncpy(hptr->line, buf, sizeof hptr->line);
 362
 363         } while (!IsEmptyStr(buf));
 364
 365         /**
 366          * If the request is prefixed by "/webcit" then chop that off.  This
 367          * allows a front end web server to forward all /webcit requests to us
 368          * while still using the same web server port for other things.
 369          */
 370
 371         ptr = strstr(req->line, " /webcit ");   /*< Handle "/webcit" */
 372         if (ptr != NULL) {
 373                 strcpy(ptr+2, ptr+8);
 374         }
 375
 376         ptr = strstr(req->line, " /webcit");    /*< Handle "/webcit/" */
 377         if (ptr != NULL) {
 378                 strcpy(ptr+1, ptr+8);
 379         }
 380
 381         safestrncpy(buf, req->line, sizeof buf);
 382         /** Begin parsing the request. */
 383 #ifdef TECH_PREVIEW
 384         if ((strncmp(req->line+4, "/sslg", 5) != 0) &&
 385             (strncmp(req->line+4, "/wholist_section", 16) != 0)) {
 386 #endif
 387                 lprintf(5, "HTTP: %s\n", buf);
 388 #ifdef TECH_PREVIEW
 389         }
 390 #endif
 391
 392         /** Check for bogus requests */
 393         if (is_bogus(buf)) {
 394                 strcpy(req->line, "GET /404 HTTP/1.1");
 395                 strcpy(buf, "GET /404 HTTP/1.1");
 396         }
 397
 398         /**
 399          * Strip out the method, leaving the URL up front...
 400          */
 401         remove_token(buf, 0, ' ');
 402         if (buf[1]==' ') buf[1]=0;
 403
 404         /**
 405          * While we're at it, gracefully handle requests for the
 406          * robots.txt and favicon.ico files.
 407          */
 408         if (!strncasecmp(buf, "/robots.txt", 11)) {
 409                 strcpy(req->line, "GET /static/robots.txt"
 410                                 "?force_close_session=yes HTTP/1.1");
 411         }
 412         else if (!strncasecmp(buf, "/favicon.ico", 12)) {
 413                 strcpy(req->line, "GET /static/favicon.ico");
 414         }
 415
 416         /**
 417          * These are the URL's which may be executed without a
 418          * session cookie already set.  If it's not one of these,
 419          * force the session to close because cookies are
 420          * probably disabled on the client browser.
 421          */
 422         else if ( (strcmp(buf, "/"))
 423                 && (strncasecmp(buf, "/listsub", 8))
 424                 && (strncasecmp(buf, "/freebusy", 9))
 425                 && (strncasecmp(buf, "/do_logout", 10))
 426                 && (strncasecmp(buf, "/groupdav", 9))
 427                 && (strncasecmp(buf, "/static", 7))
 428                 && (strncasecmp(buf, "/rss", 4))
 429                 && (strncasecmp(buf, "/404", 4))
 430                 && (got_cookie == 0)) {
 431                 strcpy(req->line, "GET /static/nocookies.html"
 432                                 "?force_close_session=yes HTTP/1.1");
 433         }
 434
 435         /**
 436          * See if there's an existing session open with the desired ID or user/pass
 437          */
 438         TheSession = NULL;
 439
 440         if (TheSession == NULL) {
 441                 pthread_mutex_lock(&SessionListMutex);
 442                 for (sptr = SessionList; sptr != NULL; sptr = sptr->next) {
 443
 444                         /** If HTTP-AUTH, look for a session with matching credentials */
 445                         if ( (!IsEmptyStr(httpauth_user))
 446                            &&(!strcasecmp(sptr->httpauth_user, httpauth_user))
 447                            &&(!strcasecmp(sptr->httpauth_pass, httpauth_pass)) ) {
 448                                 TheSession = sptr;
 449                         }
 450
 451                         /** If cookie-session, look for a session with matching session ID */
 452                         if ( (desired_session != 0) && (sptr->wc_session == desired_session)) {
 453                                 TheSession = sptr;
 454                         }
 455
 456                 }
 457                 pthread_mutex_unlock(&SessionListMutex);
 458         }
 459
 460         /**
 461          * Create a new session if we have to
 462          */
 463         if (TheSession == NULL) {
 464                 lprintf(3, "Creating a new session\n");
 465                 TheSession = (struct wcsession *)
 466                         malloc(sizeof(struct wcsession));
 467                 memset(TheSession, 0, sizeof(struct wcsession));
 468                 TheSession->serv_sock = (-1);
 469                 TheSession->chat_sock = (-1);
 470
 471                 /* If we're recreating a session that expired, it's best to give it the same
 472                  * session number that it had before.  The client browser ought to pick up
 473                  * the new session number and start using it, but in some rare situations it
 474                  * doesn't, and that's a Bad Thing because it causes lots of spurious sessions
 475                  * to get created.
 476                  */
 477                 if (desired_session == 0) {
 478                         TheSession->wc_session = GenerateSessionID();
 479                 }
 480                 else {
 481                         TheSession->wc_session = desired_session;
 482                 }
 483
 484                 strcpy(TheSession->httpauth_user, httpauth_user);
 485                 strcpy(TheSession->httpauth_pass, httpauth_pass);
 486                 TheSession->hash_prefs = NewHash(1,NULL);       /* Get a hash table for the user preferences */
 487                 pthread_mutex_init(&TheSession->SessionMutex, NULL);
 488                 pthread_mutex_lock(&SessionListMutex);
 489                 TheSession->urlstrings = NULL;
 490                 TheSession->vars = NULL;
 491                 TheSession->nonce = rand();
 492                 TheSession->WBuf = NULL;
 493                 TheSession->next = SessionList;
 494                 SessionList = TheSession;
 495                 pthread_mutex_unlock(&SessionListMutex);
 496                 session_is_new = 1;
 497         }
 498
 499         /*
 500          * A future improvement might be to check the session integrity
 501          * at this point before continuing.
 502          */
 503
 504         /*
 505          * Bind to the session and perform the transaction
 506          */
 507         pthread_mutex_lock(&TheSession->SessionMutex);          /* bind */
 508         pthread_setspecific(MyConKey, (void *)TheSession);
 509
 510         TheSession->urlstrings = NewHash(1,NULL);
 511         TheSession->vars = NewHash(1,NULL);
 512         TheSession->http_sock = sock;
 513         TheSession->lastreq = time(NULL);                       /* log */
 514         TheSession->gzip_ok = gzip_ok;
 515 #ifdef ENABLE_NLS
 516         if (session_is_new) {
 517                 httplang_to_locale(accept_language);
 518         }
 519         go_selected_language();                                 /* set locale */
 520 #endif
 521         session_loop(req);                                      /* do transaction */
 522 #ifdef ENABLE_NLS
 523         stop_selected_language();                               /* unset locale */
 524 #endif
 525         DeleteHash(&TheSession->urlstrings);
 526         DeleteHash(&TheSession->vars);
 527         FreeStrBuf(&TheSession->WBuf);
 528         FreeStrBuf(&TheSession->HBuf);
 529
 530
 531         pthread_mutex_unlock(&TheSession->SessionMutex);        /* unbind */
 532
 533         /* Free the request buffer */
 534         while (req != NULL) {
 535                 hptr = req->next;
 536                 free(req);
 537                 req = hptr;
 538         }
 539
 540         /*
 541          * Free up any session-local substitution variables which
 542          * were set during this transaction
 543          */
 544
 545
 546 }