res/res_calendar_exchange.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 2008 - 2009, Digium, Inc.
   5  *
   6  * Terry Wilson <twilson@digium.com>
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*! \file
  20  * \brief Resource for handling MS Exchange calendars
  21  */
  22
  23 /*** MODULEINFO
  24         <depend>neon</depend>
  25         <depend>ical</depend>
  26         <depend>iksemel</depend>
  27         <support_level>core</support_level>
  28 ***/
  29
  30 #include "asterisk.h"
  31
  32 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  33
  34 #include <libical/ical.h>
  35 #include <ne_session.h>
  36 #include <ne_uri.h>
  37 #include <ne_request.h>
  38 #include <ne_auth.h>
  39 #include <ne_redirect.h>
  40 #include <iksemel.h>
  41
  42 #include "asterisk/module.h"
  43 #include "asterisk/calendar.h"
  44 #include "asterisk/lock.h"
  45 #include "asterisk/config.h"
  46 #include "asterisk/astobj2.h"
  47 #include "asterisk/uuid.h"
  48
  49 static void *exchangecal_load_calendar(void *data);
  50 static void *unref_exchangecal(void *obj);
  51 static int exchangecal_write_event(struct ast_calendar_event *event);
  52
  53 static struct ast_calendar_tech exchangecal_tech = {
  54         .type = "exchange",
  55         .description = "MS Exchange calendars",
  56         .module = AST_MODULE,
  57         .load_calendar = exchangecal_load_calendar,
  58         .unref_calendar = unref_exchangecal,
  59         .write_event = exchangecal_write_event,
  60 };
  61
  62 struct exchangecal_pvt {
  63         AST_DECLARE_STRING_FIELDS(
  64                 AST_STRING_FIELD(url);
  65                 AST_STRING_FIELD(user);
  66                 AST_STRING_FIELD(secret);
  67         );
  68         struct ast_calendar *owner;
  69         ne_uri uri;
  70         ne_session *session;
  71         struct ao2_container *events;
  72 };
  73
  74 struct xmlstate {
  75         char tag[80];
  76         int in_response;
  77         int in_propstat;
  78         int in_prop;
  79         void *ptr;
  80         struct exchangecal_pvt *pvt;
  81 };
  82
  83 static int parse_tag(void *data, char *name, char **atts, int type)
  84 {
  85         struct xmlstate *state = data;
  86         char *tmp;
  87
  88         if ((tmp = strchr(name, ':'))) {
  89                 tmp++;
  90         } else {
  91                 return IKS_HOOK;
  92         }
  93
  94         ast_copy_string(state->tag, tmp, sizeof(state->tag));
  95
  96         switch (type) {
  97         case IKS_OPEN:
  98                 if (!strcasecmp(state->tag, "response")) {
  99                         struct ast_calendar_event *event;
 100
 101                         state->in_response = 1;
 102                         if (!(event = ast_calendar_event_alloc(state->pvt->owner))) {
 103                                 return IKS_NOMEM;
 104                         }
 105                         state->ptr = event;
 106                 } else if (!strcasecmp(state->tag, "propstat")) {
 107                         state->in_propstat = 1;
 108                 } else if (!strcasecmp(state->tag, "prop")) {
 109                         state->in_prop = 1;
 110                 }
 111                 break;
 112
 113         case IKS_CLOSE:
 114                 if (!strcasecmp(state->tag, "response")) {
 115                         struct ao2_container *events = state->pvt->events;
 116                         struct ast_calendar_event *event = state->ptr;
 117
 118                         state->in_response = 0;
 119                         if (ast_strlen_zero(event->uid)) {
 120                                 ast_log(LOG_ERROR, "This event has no UID, something has gone wrong\n");
 121                                 event = ast_calendar_unref_event(event);
 122                                 return IKS_HOOK;
 123                         }
 124                         ao2_link(events, event);
 125                         event = ast_calendar_unref_event(event);
 126                 } else if (!strcasecmp(state->tag, "propstat")) {
 127                         state->in_propstat = 0;
 128                 } else if (!strcasecmp(state->tag, "prop")) {
 129                         state->in_prop = 0;
 130                 }
 131                 break;
 132
 133         default:
 134                 return IKS_OK;
 135         }
 136
 137         return IKS_OK;
 138 }
 139
 140 static time_t mstime_to_time_t(char *mstime)
 141 {
 142         char *read, *write;
 143         icaltimetype tt;
 144         for (read = write = mstime; *read; read++) {
 145                 if (*read == '.') {
 146                         *write++ = 'Z';
 147                         *write = '\0';
 148                         break;
 149                 }
 150                 if (*read == '-' || *read == ':')
 151                         continue;
 152                 *write = *read;
 153                 write++;
 154         }
 155
 156         tt = icaltime_from_string(mstime);
 157         return icaltime_as_timet(tt);
 158 }
 159
 160 static enum ast_calendar_busy_state msbusy_to_bs(const char *msbusy)
 161 {
 162         if (!strcasecmp(msbusy, "FREE")) {
 163                 return AST_CALENDAR_BS_FREE;
 164         } else if (!strcasecmp(msbusy, "TENTATIVE")) {
 165                 return AST_CALENDAR_BS_BUSY_TENTATIVE;
 166         } else {
 167                 return AST_CALENDAR_BS_BUSY;
 168         }
 169 }
 170
 171 static int parse_cdata(void *data, char *value, size_t len)
 172 {
 173         char *str;
 174         struct xmlstate *state = data;
 175         struct ast_calendar_event *event = state->ptr;
 176
 177
 178         str = ast_skip_blanks(value);
 179
 180         if (str == value + len)
 181                 return IKS_OK;
 182
 183         if (!(str = ast_calloc(1, len + 1))) {
 184                 return IKS_NOMEM;
 185         }
 186         memcpy(str, value, len);
 187         if (!(state->in_response && state->in_propstat && state->in_prop)) {
 188                 ast_free(str);
 189                 return IKS_OK;
 190         }
 191         /* We use ast_string_field_build here because libiksemel is parsing CDATA with &lt; as
 192          * new elements which is a bit odd and shouldn't happen */
 193         if (!strcasecmp(state->tag, "subject")) {
 194                 ast_string_field_build(event, summary, "%s%s", event->summary, str);
 195         } else if (!strcasecmp(state->tag, "location")) {
 196                 ast_string_field_build(event, location, "%s%s", event->location, str);
 197         } else if (!strcasecmp(state->tag, "uid")) {
 198                 ast_string_field_build(event, uid, "%s%s", event->location, str);
 199         } else if (!strcasecmp(state->tag, "organizer")) {
 200                 ast_string_field_build(event, organizer, "%s%s", event->organizer, str);
 201         } else if (!strcasecmp(state->tag, "textdescription")) {
 202                 ast_string_field_build(event, description, "%s%s", event->description, str);
 203         } else if (!strcasecmp(state->tag, "dtstart")) {
 204                 event->start = mstime_to_time_t(str);
 205         } else if (!strcasecmp(state->tag, "dtend")) {
 206                 event->end = mstime_to_time_t(str);
 207         } else if (!strcasecmp(state->tag, "busystatus")) {
 208                 event->busy_state = msbusy_to_bs(str);
 209         } else if (!strcasecmp(state->tag, "reminderoffset")) {
 210                 /*XXX Currently we rely on event->start being set first which means we rely on the response order
 211                  * which technically should be fine since the query returns in the order we ask for, but ... */
 212                 event->alarm = event->start - atoi(str);
 213         }
 214
 215         ast_free(str);
 216         return IKS_OK;
 217 }
 218
 219 static void exchangecal_destructor(void *obj)
 220 {
 221         struct exchangecal_pvt *pvt = obj;
 222
 223         ast_debug(1, "Destroying pvt for Exchange calendar %s\n", pvt->owner->name);
 224         if (pvt->session) {
 225                 ne_session_destroy(pvt->session);
 226         }
 227         ast_string_field_free_memory(pvt);
 228
 229         ao2_callback(pvt->events, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, NULL, NULL);
 230
 231         ao2_ref(pvt->events, -1);
 232 }
 233
 234 static void *unref_exchangecal(void *obj)
 235 {
 236         struct exchangecal_pvt *pvt = obj;
 237
 238         ao2_ref(pvt, -1);
 239         return NULL;
 240 }
 241
 242 /* It is very important to use the return value of this function as a realloc could occur */
 243 static struct ast_str *generate_exchange_uuid(struct ast_str *uid)
 244 {
 245         char buffer[AST_UUID_STR_LEN];
 246         struct ast_uuid *uuid = ast_uuid_generate();
 247
 248         if (!uuid) {
 249                 return NULL;
 250         }
 251
 252         ast_str_set(&uid, 0, "%s", ast_uuid_to_str(uuid, buffer, AST_UUID_STR_LEN));
 253
 254         ast_free(uuid);
 255
 256         return uid;
 257 }
 258
 259 static int is_valid_uuid(struct ast_str *uid)
 260 {
 261         struct ast_uuid *uuid = ast_str_to_uuid(ast_str_buffer(uid));
 262
 263         if (uuid) {
 264                 ast_free(uuid);
 265                 return 1;
 266         }
 267
 268         return 0;
 269 }
 270
 271 static struct ast_str *xml_encode_str(struct ast_str *dst, const char *src)
 272 {
 273         const char *tmp;
 274         char buf[7];
 275
 276         for (tmp = src; *tmp; tmp++) {
 277                 switch (*tmp) {
 278                 case '\"':
 279                         strcpy(buf, "&quot;");
 280                         break;
 281
 282                 case '\'':
 283                         strcpy(buf, "&apos;");
 284                         break;
 285
 286                 case '&':
 287                         strcpy(buf, "&amp;");
 288                         break;
 289
 290                 case '<':
 291                         strcpy(buf, "&lt;");
 292                         break;
 293
 294                 case '>':
 295                         strcpy(buf, "&gt;");
 296                         break;
 297
 298                 default:
 299                         sprintf(buf, "%c", *tmp);
 300                 }
 301
 302                 ast_str_append(&dst, 0, "%s", buf);
 303         }
 304
 305         return dst;
 306 }
 307
 308 static struct ast_str *epoch_to_exchange_time(struct ast_str *dst, time_t epoch)
 309 {
 310         icaltimezone *utc = icaltimezone_get_utc_timezone();
 311         icaltimetype tt = icaltime_from_timet_with_zone(epoch, 0, utc);
 312         char tmp[30];
 313         int i;
 314
 315         ast_copy_string(tmp, icaltime_as_ical_string(tt), sizeof(tmp));
 316         for (i = 0; tmp[i]; i++) {
 317                 ast_str_append(&dst, 0, "%c", tmp[i]);
 318                 if (i == 3 || i == 5)
 319                         ast_str_append(&dst, 0, "%c", '-');
 320                 if (i == 10 || i == 12)
 321                         ast_str_append(&dst, 0, "%c", ':');
 322                 if (i == 14)
 323                         ast_str_append(&dst, 0, "%s", ".000");
 324         }
 325
 326         return dst;
 327 }
 328
 329 static struct ast_str *bs_to_exchange_bs(struct ast_str *dst, enum ast_calendar_busy_state bs)
 330 {
 331         switch (bs) {
 332         case AST_CALENDAR_BS_BUSY:
 333                 ast_str_set(&dst, 0, "%s", "BUSY");
 334                 break;
 335
 336         case AST_CALENDAR_BS_BUSY_TENTATIVE:
 337                 ast_str_set(&dst, 0, "%s", "TENTATIVE");
 338                 break;
 339
 340         default:
 341                 ast_str_set(&dst, 0, "%s", "FREE");
 342         }
 343
 344         return dst;
 345 }
 346
 347 static int fetch_response_reader(void *data, const char *block, size_t len)
 348 {
 349         struct ast_str **response = data;
 350         unsigned char *tmp;
 351
 352         if (!(tmp = ast_malloc(len + 1))) {
 353                 return -1;
 354         }
 355         memcpy(tmp, block, len);
 356         tmp[len] = '\0';
 357         ast_str_append(response, 0, "%s", tmp);
 358         ast_free(tmp);
 359
 360         return 0;
 361 }
 362
 363 static int auth_credentials(void *userdata, const char *realm, int attempts, char *username, char *secret)
 364 {
 365         struct exchangecal_pvt *pvt = userdata;
 366
 367         if (attempts > 1) {
 368                 ast_log(LOG_WARNING, "Invalid username or password for Exchange calendar '%s'\n", pvt->owner->name);
 369                 return -1;
 370         }
 371
 372         ne_strnzcpy(username, pvt->user, NE_ABUFSIZ);
 373         ne_strnzcpy(secret, pvt->secret, NE_ABUFSIZ);
 374
 375         return 0;
 376 }
 377
 378 static struct ast_str *exchangecal_request(struct exchangecal_pvt *pvt, const char *method, struct ast_str *req_body, struct ast_str *subdir)
 379 {
 380         struct ast_str *response;
 381         ne_request *req;
 382         int ret;
 383         char buf[1000];
 384
 385         if (!pvt) {
 386                 ast_log(LOG_ERROR, "There is no private!\n");
 387                 return NULL;
 388         }
 389
 390         if (!(response = ast_str_create(512))) {
 391                 ast_log(LOG_ERROR, "Could not allocate memory for response.\n");
 392                 return NULL;
 393         }
 394
 395         snprintf(buf, sizeof(buf), "%s%s", pvt->uri.path, subdir ? ast_str_buffer(subdir) : "");
 396
 397         req = ne_request_create(pvt->session, method, buf);
 398         ne_add_response_body_reader(req, ne_accept_2xx, fetch_response_reader, &response);
 399         ne_set_request_body_buffer(req, ast_str_buffer(req_body), ast_str_strlen(req_body));
 400         ne_add_request_header(req, "Content-type", "text/xml");
 401
 402         ret = ne_request_dispatch(req);
 403         ne_request_destroy(req);
 404
 405         if (ret != NE_OK || !ast_str_strlen(response)) {
 406                 ast_log(LOG_WARNING, "Unknown response to CalDAV calendar %s, request %s to %s: %s\n", pvt->owner->name, method, pvt->url, ne_get_error(pvt->session));
 407                 ast_free(response);
 408                 return NULL;
 409         }
 410
 411         return response;
 412 }
 413
 414 static int exchangecal_write_event(struct ast_calendar_event *event)
 415 {
 416         struct ast_str *body = NULL, *response = NULL, *subdir = NULL;
 417         struct ast_str *uid = NULL, *summary = NULL, *description = NULL, *organizer = NULL,
 418                        *location = NULL, *start = NULL, *end = NULL, *busystate = NULL;
 419         int ret = -1;
 420
 421         if (!event) {
 422                 ast_log(LOG_WARNING, "No event passed!\n");
 423                 return -1;
 424         }
 425
 426         if (!(event->start && event->end)) {
 427                 ast_log(LOG_WARNING, "The event must contain a start and an end\n");
 428                 return -1;
 429         }
 430         if (!(body = ast_str_create(512)) ||
 431                 !(subdir = ast_str_create(32))) {
 432                 ast_log(LOG_ERROR, "Could not allocate memory for request!\n");
 433                 goto write_cleanup;
 434         }
 435
 436         if (!(uid = ast_str_create(32)) ||
 437                 !(summary = ast_str_create(32)) ||
 438                 !(description = ast_str_create(32)) ||
 439                 !(organizer = ast_str_create(32)) ||
 440                 !(location = ast_str_create(32)) ||
 441                 !(start = ast_str_create(32)) ||
 442                 !(end = ast_str_create(32)) ||
 443                 !(busystate = ast_str_create(32))) {
 444                 ast_log(LOG_ERROR, "Unable to allocate memory for request values\n");
 445                 goto write_cleanup;
 446         }
 447
 448         if (ast_strlen_zero(event->uid)) {
 449                 uid = generate_exchange_uuid(uid);
 450         } else {
 451                 ast_str_set(&uid, 36, "%s", event->uid);
 452         }
 453
 454         if (!is_valid_uuid(uid)) {
 455                 ast_log(LOG_WARNING, "An invalid uid was provided, you may leave this field blank to have one generated for you\n");
 456                 goto write_cleanup;
 457         }
 458
 459         summary = xml_encode_str(summary, event->summary);
 460         description = xml_encode_str(description, event->description);
 461         organizer = xml_encode_str(organizer, event->organizer);
 462         location = xml_encode_str(location, event->location);
 463         start = epoch_to_exchange_time(start, event->start);
 464         end = epoch_to_exchange_time(end, event->end);
 465         busystate = bs_to_exchange_bs(busystate, event->busy_state);
 466
 467         ast_str_append(&body, 0,
 468                 "<?xml version=\"1.0\"?>\n"
 469                 "<a:propertyupdate\n"
 470                 "  xmlns:a=\"DAV:\"\n"
 471                 "  xmlns:e=\"http://schemas.microsoft.com/exchange/\"\n"
 472                 "  xmlns:mapi=\"http://schemas.microsoft.com/mapi/\"\n"
 473                 "  xmlns:mapit=\"http://schemas.microsoft.com/mapi/proptag/\"\n"
 474                 "  xmlns:x=\"xml:\" xmlns:cal=\"urn:schemas:calendar:\"\n"
 475                 "  xmlns:dt=\"uuid:%s/\"\n" /* uid */
 476                 "  xmlns:header=\"urn:schemas:mailheader:\"\n"
 477                 "  xmlns:mail=\"urn:schemas:httpmail:\"\n"
 478                 ">\n"
 479                 "    <a:set>\n"
 480                 "      <a:prop>\n"
 481                 "        <a:contentclass>urn:content-classes:appointment</a:contentclass>\n"
 482                 "        <e:outlookmessageclass>IPM.Appointment</e:outlookmessageclass>\n"
 483                 "        <mail:subject>%s</mail:subject>\n" /* summary */
 484                 "        <mail:description>%s</mail:description>\n" /* description */
 485                 "        <header:to>%s</header:to>\n" /* organizer */
 486                 "        <cal:location>%s</cal:location>\n" /* location */
 487                 "        <cal:dtstart dt:dt=\"dateTime.tz\">%s</cal:dtstart>\n" /* start */
 488                 "        <cal:dtend dt:dt=\"dateTime.tz\">%s</cal:dtend>\n" /* end */
 489                 "        <cal:instancetype dt:dt=\"int\">0</cal:instancetype>\n"
 490                 "        <cal:busystatus>%s</cal:busystatus>\n" /* busy_state (BUSY, FREE, BUSY_TENTATIVE) */
 491                 "        <cal:meetingstatus>CONFIRMED</cal:meetingstatus>\n"
 492                 "        <cal:alldayevent dt:dt=\"boolean\">0</cal:alldayevent>\n" /* XXX need to add event support for all day events */
 493                 "        <cal:responserequested dt:dt=\"boolean\">0</cal:responserequested>\n"
 494                 "        <mapi:finvited dt:dt=\"boolean\">1</mapi:finvited>\n"
 495                 "      </a:prop>\n"
 496                 "    </a:set>\n"
 497                 "</a:propertyupdate>\n",
 498                 ast_str_buffer(uid), ast_str_buffer(summary), ast_str_buffer(description), ast_str_buffer(organizer), ast_str_buffer(location), ast_str_buffer(start), ast_str_buffer(end), ast_str_buffer(busystate));
 499         ast_verb(0, "\n\n%s\n\n", ast_str_buffer(body));
 500         ast_str_set(&subdir, 0, "/Calendar/%s.eml", ast_str_buffer(uid));
 501
 502         if ((response = exchangecal_request(event->owner->tech_pvt, "PROPPATCH", body, subdir))) {
 503                 ret = 0;
 504         }
 505
 506 write_cleanup:
 507         if (uid) {
 508                 ast_free(uid);
 509         }
 510         if (summary) {
 511                 ast_free(summary);
 512         }
 513         if (description) {
 514                 ast_free(description);
 515         }
 516         if (organizer) {
 517                 ast_free(organizer);
 518         }
 519         if (location) {
 520                 ast_free(location);
 521         }
 522         if (start) {
 523                 ast_free(start);
 524         }
 525         if (end) {
 526                 ast_free(end);
 527         }
 528         if (busystate) {
 529                 ast_free(busystate);
 530         }
 531         if (body) {
 532                 ast_free(body);
 533         }
 534         if (response) {
 535                 ast_free(response);
 536         }
 537         if (subdir) {
 538                 ast_free(subdir);
 539         }
 540
 541         return ret;
 542 }
 543
 544
 545 static struct ast_str *exchangecal_get_events_between(struct exchangecal_pvt *pvt, time_t start_time, time_t end_time)
 546 {
 547         struct ast_str *body, *response;
 548         char start[80], end[80];
 549         struct timeval tv = {0,};
 550         struct ast_tm tm;
 551
 552         tv.tv_sec = start_time;
 553         ast_localtime(&tv, &tm, "UTC");
 554         ast_strftime(start, sizeof(start), "%Y/%m/%d %T", &tm);
 555
 556         tv.tv_sec = end_time;
 557         ast_localtime(&tv, &tm, "UTC");
 558         ast_strftime(end, sizeof(end), "%Y/%m/%d %T", &tm);
 559
 560         if (!(body = ast_str_create(512))) {
 561                 ast_log(LOG_ERROR, "Could not allocate memory for body of request!\n");
 562                 return NULL;
 563         }
 564
 565         ast_str_append(&body, 0,
 566                 "<?xml version=\"1.0\"?>\n"
 567                 "<g:searchrequest xmlns:g=\"DAV:\">\n"
 568                 "        <g:sql> SELECT \"urn:schemas:calendar:location\", \"urn:schemas:httpmail:subject\",\n"
 569                 "                \"urn:schemas:calendar:dtstart\", \"urn:schemas:calendar:dtend\",\n"
 570                 "                \"urn:schemas:calendar:busystatus\", \"urn:schemas:calendar:instancetype\",\n"
 571                 "                \"urn:schemas:calendar:uid\", \"urn:schemas:httpmail:textdescription\",\n"
 572                 "                \"urn:schemas:calendar:organizer\", \"urn:schemas:calendar:reminderoffset\"\n"
 573                 "                FROM Scope('SHALLOW TRAVERSAL OF \"%s/Calendar\"')\n"
 574                 "                WHERE NOT \"urn:schemas:calendar:instancetype\" = 1\n"
 575                 "                AND \"DAV:contentclass\" = 'urn:content-classes:appointment'\n"
 576                 "                AND NOT (\"urn:schemas:calendar:dtend\" &lt; '%s'\n"
 577                 "                OR \"urn:schemas:calendar:dtstart\" &gt; '%s')\n"
 578                 "                ORDER BY \"urn:schemas:calendar:dtstart\" ASC\n"
 579                 "         </g:sql>\n"
 580                 "</g:searchrequest>\n", pvt->url, start, end);
 581
 582         ast_debug(5, "Request:\n%s\n", ast_str_buffer(body));
 583         response = exchangecal_request(pvt, "SEARCH", body, NULL);
 584         ast_debug(5, "Response:\n%s\n", ast_str_buffer(response));
 585         ast_free(body);
 586
 587         return response;
 588 }
 589
 590 static int update_exchangecal(struct exchangecal_pvt *pvt)
 591 {
 592         struct xmlstate state;
 593         struct timeval now = ast_tvnow();
 594         time_t start, end;
 595         struct ast_str *response;
 596         iksparser *p;
 597
 598         state.pvt = pvt;
 599         start = now.tv_sec;
 600         end = now.tv_sec + 60 * pvt->owner->timeframe;
 601         if (!(response = exchangecal_get_events_between(pvt, start, end))) {
 602                 return -1;
 603         }
 604
 605         p = iks_sax_new(&state, parse_tag, parse_cdata);
 606         iks_parse(p, ast_str_buffer(response), ast_str_strlen(response), 1);
 607         ast_calendar_merge_events(pvt->owner, pvt->events);
 608         ast_free(response);
 609
 610         return 0;
 611 }
 612
 613 static void *exchangecal_load_calendar(void *void_data)
 614 {
 615         struct exchangecal_pvt *pvt;
 616         const struct ast_config *cfg;
 617         struct ast_variable *v;
 618         struct ast_calendar *cal = void_data;
 619         ast_mutex_t refreshlock;
 620
 621         if (!(cal && (cfg = ast_calendar_config_acquire()))) {
 622                 ast_log(LOG_ERROR, "You must enable calendar support for res_exchangecal to load\n");
 623                 return NULL;
 624         }
 625
 626         if (ao2_trylock(cal)) {
 627                 if (cal->unloading) {
 628                         ast_log(LOG_WARNING, "Unloading module, load_calendar cancelled.\n");
 629                 } else {
 630                         ast_log(LOG_WARNING, "Could not lock calendar, aborting!\n");
 631                 }
 632                 ast_calendar_config_release();
 633                 return NULL;
 634         }
 635
 636         if (!(pvt = ao2_alloc(sizeof(*pvt), exchangecal_destructor))) {
 637                 ast_log(LOG_ERROR, "Could not allocate exchangecal_pvt structure for calendar: %s\n", cal->name);
 638                 ast_calendar_config_release();
 639                 return NULL;
 640         }
 641
 642         pvt->owner = cal;
 643
 644         if (!(pvt->events = ast_calendar_event_container_alloc())) {
 645                 ast_log(LOG_ERROR, "Could not allocate space for fetching events for calendar: %s\n", cal->name);
 646                 pvt = unref_exchangecal(pvt);
 647                 ao2_unlock(cal);
 648                 ast_calendar_config_release();
 649                 return NULL;
 650         }
 651
 652         if (ast_string_field_init(pvt, 32)) {
 653                 ast_log(LOG_ERROR, "Couldn't allocate string field space for calendar: %s\n", cal->name);
 654                 pvt = unref_exchangecal(pvt);
 655                 ao2_unlock(cal);
 656                 ast_calendar_config_release();
 657                 return NULL;
 658         }
 659
 660         for (v = ast_variable_browse(cfg, cal->name); v; v = v->next) {
 661                 if (!strcasecmp(v->name, "url")) {
 662                         ast_string_field_set(pvt, url, v->value);
 663                 } else if (!strcasecmp(v->name, "user")) {
 664                         ast_string_field_set(pvt, user, v->value);
 665                 } else if (!strcasecmp(v->name, "secret")) {
 666                         ast_string_field_set(pvt, secret, v->value);
 667                 }
 668         }
 669
 670         ast_calendar_config_release();
 671
 672         if (ast_strlen_zero(pvt->url)) {
 673                 ast_log(LOG_WARNING, "No URL was specified for Exchange calendar '%s' - skipping.\n", cal->name);
 674                 pvt = unref_exchangecal(pvt);
 675                 ao2_unlock(cal);
 676                 return NULL;
 677         }
 678
 679         if (ne_uri_parse(pvt->url, &pvt->uri) || pvt->uri.host == NULL || pvt->uri.path == NULL) {
 680                 ast_log(LOG_WARNING, "Could not parse url '%s' for Exchange calendar '%s' - skipping.\n", pvt->url, cal->name);
 681                 pvt = unref_exchangecal(pvt);
 682                 ao2_unlock(cal);
 683                 return NULL;
 684         }
 685
 686         if (pvt->uri.scheme == NULL) {
 687                 pvt->uri.scheme = "http";
 688         }
 689
 690         if (pvt->uri.port == 0) {
 691                 pvt->uri.port = ne_uri_defaultport(pvt->uri.scheme);
 692         }
 693
 694         pvt->session = ne_session_create(pvt->uri.scheme, pvt->uri.host, pvt->uri.port);
 695         ne_redirect_register(pvt->session);
 696         ne_set_server_auth(pvt->session, auth_credentials, pvt);
 697         if (!strcasecmp(pvt->uri.scheme, "https")) {
 698                 ne_ssl_trust_default_ca(pvt->session);
 699         }
 700
 701         cal->tech_pvt = pvt;
 702
 703         ast_mutex_init(&refreshlock);
 704
 705         /* Load it the first time */
 706         update_exchangecal(pvt);
 707
 708         ao2_unlock(cal);
 709
 710         /* The only writing from another thread will be if unload is true */
 711         for (;;) {
 712                 struct timeval tv = ast_tvnow();
 713                 struct timespec ts = {0,};
 714
 715                 ts.tv_sec = tv.tv_sec + (60 * pvt->owner->refresh);
 716
 717                 ast_mutex_lock(&refreshlock);
 718                 while (!pvt->owner->unloading) {
 719                         if (ast_cond_timedwait(&pvt->owner->unload, &refreshlock, &ts) == ETIMEDOUT) {
 720                                 break;
 721                         }
 722                 }
 723                 ast_mutex_unlock(&refreshlock);
 724
 725                 if (pvt->owner->unloading) {
 726                         ast_debug(10, "Skipping refresh since we got a shutdown signal\n");
 727                         return NULL;
 728                 }
 729
 730                 ast_debug(10, "Refreshing after %d minute timeout\n", pvt->owner->refresh);
 731
 732                 update_exchangecal(pvt);
 733         }
 734
 735         return NULL;
 736 }
 737
 738 static int load_module(void)
 739 {
 740         ne_sock_init();
 741         if (ast_calendar_register(&exchangecal_tech)) {
 742                 ne_sock_exit();
 743                 return AST_MODULE_LOAD_DECLINE;
 744         }
 745
 746         return AST_MODULE_LOAD_SUCCESS;
 747 }
 748
 749 static int unload_module(void)
 750 {
 751         ast_calendar_unregister(&exchangecal_tech);
 752         ne_sock_exit();
 753         return 0;
 754 }
 755
 756 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Asterisk MS Exchange Calendar Integration",
 757                 .load = load_module,
 758                 .unload = unload_module,
 759                 .load_pri = AST_MODPRI_DEVSTATE_PLUGIN,
 760         );