citadel/modules/smtp/serv_smtpclient.c

   1 /*
   2  * Transmit outbound SMTP mail to the big wide world of the Internet
   3  *
   4  * This is the new, exciting, clever version that makes libcurl do all the work  :)
   5  *
   6  * Copyright (c) 1997-2018 by the citadel.org team
   7  *
   8  * This program is open source software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as published
  10  * by the Free Software Foundation; either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <stdlib.h>
  20 #include <unistd.h>
  21 #include <stdio.h>
  22 #include <sysconfig.h>
  23
  24 #if TIME_WITH_SYS_TIME
  25 # include <sys/time.h>
  26 # include <time.h>
  27 #else
  28 # if HAVE_SYS_TIME_H
  29 #  include <sys/time.h>
  30 # else
  31 #  include <time.h>
  32 # endif
  33 #endif
  34
  35 #include <ctype.h>
  36 #include <string.h>
  37 #include <errno.h>
  38 #include <sys/types.h>
  39 #include <sys/stat.h>
  40 #include <libcitadel.h>
  41 #include <curl/curl.h>
  42 #include "citadel.h"
  43 #include "server.h"
  44 #include "citserver.h"
  45 #include "support.h"
  46 #include "config.h"
  47 #include "ctdl_module.h"
  48 #include "clientsocket.h"
  49 #include "msgbase.h"
  50 #include "domain.h"
  51 #include "internet_addressing.h"
  52 #include "citadel_dirs.h"
  53 #include "modules/smtp/smtp_util.h"
  54
  55 struct smtpmsgsrc {             // Data passed in and out of libcurl for message upload
  56         StrBuf *TheMessage;
  57         int bytes_total;
  58         int bytes_sent;
  59 };
  60
  61 struct CitContext smtp_client_CC;
  62 static int doing_smtpclient = 0;
  63 long *smtpq = NULL;             // array of msgnums containing queue instructions
  64 int smtpq_count = 0;            // number of queue messages in smtpq
  65 int smtpq_alloc = 0;            // current allocation size for smtpq
  66
  67
  68 /*
  69  * Initialize the SMTP outbound queue
  70  */
  71 void smtp_init_spoolout(void) {
  72         struct ctdlroom qrbuf;
  73
  74         /*
  75          * Create the room.  This will silently fail if the room already
  76          * exists, and that's perfectly ok, because we want it to exist.
  77          */
  78         CtdlCreateRoom(SMTP_SPOOLOUT_ROOM, 3, "", 0, 1, 0, VIEW_QUEUE);
  79
  80         /*
  81          * Make sure it's set to be a "system room" so it doesn't show up
  82          * in the <K>nown rooms list for administrators.
  83          */
  84         if (CtdlGetRoomLock(&qrbuf, SMTP_SPOOLOUT_ROOM) == 0) {
  85                 qrbuf.QRflags2 |= QR2_SYSTEM;
  86                 CtdlPutRoomLock(&qrbuf);
  87         }
  88 }
  89
  90
  91 /* For internet mail, generate delivery instructions.
  92  * Yes, this is recursive.  Deal with it.  Infinite recursion does
  93  * not happen because the delivery instructions message does not
  94  * contain a recipient.
  95  */
  96 int smtp_aftersave(struct CtdlMessage *msg, recptypes *recps)
  97 {
  98         if ((recps != NULL) && (recps->num_internet > 0)) {
  99                 struct CtdlMessage *imsg = NULL;
 100                 char recipient[SIZ];
 101                 StrBuf *SpoolMsg = NewStrBuf();
 102                 long nTokens;
 103                 int i;
 104
 105                 syslog(LOG_DEBUG, "smtpclient: generating delivery instructions");
 106
 107                 StrBufPrintf(SpoolMsg,
 108                              "Content-type: "SPOOLMIME"\n"
 109                              "\n"
 110                              "msgid|%s\n"
 111                              "submitted|%ld\n"
 112                              "bounceto|%s\n",
 113                              msg->cm_fields[eVltMsgNum],
 114                              (long)time(NULL),
 115                              recps->bounce_to
 116                 );
 117
 118                 if (recps->envelope_from != NULL) {
 119                         StrBufAppendBufPlain(SpoolMsg, HKEY("envelope_from|"), 0);
 120                         StrBufAppendBufPlain(SpoolMsg, recps->envelope_from, -1, 0);
 121                         StrBufAppendBufPlain(SpoolMsg, HKEY("\n"), 0);
 122                 }
 123                 if (recps->sending_room != NULL) {
 124                         StrBufAppendBufPlain(SpoolMsg, HKEY("source_room|"), 0);
 125                         StrBufAppendBufPlain(SpoolMsg, recps->sending_room, -1, 0);
 126                         StrBufAppendBufPlain(SpoolMsg, HKEY("\n"), 0);
 127                 }
 128
 129                 nTokens = num_tokens(recps->recp_internet, '|');
 130                 for (i = 0; i < nTokens; i++) {
 131                         long len;
 132                         len = extract_token(recipient, recps->recp_internet, i, '|', sizeof recipient);
 133                         if (len > 0) {
 134                                 StrBufAppendBufPlain(SpoolMsg, HKEY("remote|"), 0);
 135                                 StrBufAppendBufPlain(SpoolMsg, recipient, len, 0);
 136                                 StrBufAppendBufPlain(SpoolMsg, HKEY("|0||\n"), 0);
 137                         }
 138                 }
 139
 140                 imsg = malloc(sizeof(struct CtdlMessage));
 141                 memset(imsg, 0, sizeof(struct CtdlMessage));
 142                 imsg->cm_magic = CTDLMESSAGE_MAGIC;
 143                 imsg->cm_anon_type = MES_NORMAL;
 144                 imsg->cm_format_type = FMT_RFC822;
 145                 CM_SetField(imsg, eMsgSubject, HKEY("QMSG"));
 146                 CM_SetField(imsg, eAuthor, HKEY("Citadel"));
 147                 CM_SetField(imsg, eJournal, HKEY("do not journal"));
 148                 CM_SetAsFieldSB(imsg, eMesageText, &SpoolMsg);
 149                 CtdlSubmitMsg(imsg, NULL, SMTP_SPOOLOUT_ROOM, QP_EADDR);
 150                 CM_Free(imsg);
 151         }
 152         return 0;
 153 }
 154
 155
 156 /*
 157  * Callback for smtp_attempt_delivery() to supply libcurl with upload data.
 158  */
 159 static size_t upload_source(void *ptr, size_t size, size_t nmemb, void *userp)
 160 {
 161         struct smtpmsgsrc *s = (struct smtpmsgsrc *) userp;
 162         int sendbytes = 0;
 163         const char *send_this = NULL;
 164
 165         sendbytes = (size * nmemb);
 166
 167         if (s->bytes_sent >= s->bytes_total) {
 168                 return(0);                                      // no data remaining; we are done
 169         }
 170
 171         if (sendbytes > (s->bytes_total - s->bytes_sent)) {
 172                 sendbytes = s->bytes_total - s->bytes_sent;     // can't send more than we have
 173         }
 174
 175         send_this = ChrPtr(s->TheMessage);
 176         send_this += s->bytes_sent;                             // start where we last left off
 177
 178         memcpy(ptr, send_this, sendbytes);
 179         s->bytes_sent += sendbytes;
 180         return(sendbytes);                                      // return the number of bytes _actually_ copied
 181 }
 182
 183
 184 /*
 185  * The libcurl API doesn't provide a way to capture the actual SMTP result message returned
 186  * by the remote server.  This is an ugly way to extract it, by capturing debug data from
 187  * the library and filtering on the lines we want.
 188  */
 189 int ctdl_libcurl_smtp_debug_callback(CURL *handle, curl_infotype type, char *data, size_t size, void *userptr)
 190 {
 191         if (type != CURLINFO_HEADER_IN) return 0;
 192         if (!userptr) return 0;
 193         char *debugbuf = (char *)userptr;
 194
 195         int len = strlen(debugbuf);
 196         if (len + size > SIZ) return 0;
 197
 198         memcpy(&debugbuf[len], data, size);
 199         debugbuf[len+size] = 0;
 200         return 0;
 201 }
 202
 203
 204 /*
 205  * Attempt a delivery to one recipient.
 206  * Returns a three-digit SMTP status code.
 207  */
 208 int smtp_attempt_delivery(long msgid, char *recp, char *envelope_from, char *response)
 209 {
 210         struct smtpmsgsrc s;
 211         char *fromaddr = NULL;
 212         CURL *curl;
 213         CURLcode res = CURLE_OK;
 214         struct curl_slist *recipients = NULL;
 215         long response_code = 421;
 216         int num_mx = 0;
 217         char mxes[SIZ];
 218         char user[1024];
 219         char node[1024];
 220         char name[1024];
 221         char try_this_mx[256];
 222         char smtp_url[512];
 223         int i;
 224
 225         syslog(LOG_DEBUG, "smtpclient: smtp_attempt_delivery(%ld, %s)", msgid, recp);
 226
 227         process_rfc822_addr(recp, user, node, name);            // split recipient address into username, hostname, displayname
 228         num_mx = getmx(mxes, node);
 229         if (num_mx < 1) {
 230                 return(421);
 231         }
 232
 233         CC->redirect_buffer = NewStrBufPlain(NULL, SIZ);
 234         CtdlOutputMsg(msgid, MT_RFC822, HEADERS_ALL, 0, 1, NULL, 0, NULL, &fromaddr, NULL);
 235         s.TheMessage = CC->redirect_buffer;
 236         s.bytes_total =  StrLength(CC->redirect_buffer);
 237         s.bytes_sent = 0;
 238         CC->redirect_buffer = NULL;
 239         response_code = 421;
 240
 241         for (i=0; ((i<num_mx)&&((response_code/100)==4)); ++i) {                                // keep trying MXes until one works or we run out
 242                 response_code = 421;                                                            // default 421 makes non-protocol errors transient
 243                 s.bytes_sent = 0;                                                               // rewind our buffer in case we try multiple MXes
 244
 245                 curl = curl_easy_init();
 246                 if (curl) {
 247                         response[0] = 0;
 248
 249                         if (!IsEmptyStr(envelope_from)) {
 250                                 curl_easy_setopt(curl, CURLOPT_MAIL_FROM, envelope_from);
 251                         }
 252                         else {
 253                                 curl_easy_setopt(curl, CURLOPT_MAIL_FROM, fromaddr);
 254                         }
 255
 256                         recipients = curl_slist_append(recipients, recp);
 257                         curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
 258                         curl_easy_setopt(curl, CURLOPT_READFUNCTION, upload_source);
 259                         curl_easy_setopt(curl, CURLOPT_READDATA, &s);
 260                         curl_easy_setopt(curl, CURLOPT_UPLOAD, 1);                                              // tell libcurl we are uploading
 261                         curl_easy_setopt(curl, CURLOPT_TIMEOUT, 20L);                                           // Time out after 20 seconds
 262                         if (CtdlGetConfigInt("c_smtpclient_disable_starttls") == 0) {
 263                                 curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_TRY);                        // Attempt STARTTLS if offered
 264                         }
 265                         curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
 266                         curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
 267                         curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, ctdl_libcurl_smtp_debug_callback);
 268                         curl_easy_setopt(curl, CURLOPT_DEBUGDATA, (void *)response);
 269                         curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
 270
 271                         // Construct an SMTP URL in the form of:
 272                         //      smtp[s]://target_host/source_host
 273                         // This looks weird but libcurl uses that last part to set our name for EHLO or HELO.
 274                         // We check for "smtp://" and "smtps://" because the admin may have put those prefixes in a smart-host entry.
 275                         // If there is no prefix we add "smtp://"
 276                         extract_token(try_this_mx, mxes, i, '|', (sizeof try_this_mx - 7));
 277                         snprintf(smtp_url, sizeof smtp_url,
 278                                 "%s%s/%s",
 279                                 (((!strncasecmp(try_this_mx, HKEY("smtp://"))) || (!strncasecmp(try_this_mx, HKEY("smtps://")))) ? "" : "smtp://"),
 280                                 try_this_mx,
 281                                 CtdlGetConfigStr("c_fqdn")
 282                         );
 283                         curl_easy_setopt(curl, CURLOPT_URL, smtp_url);
 284                         syslog(LOG_DEBUG, "smtpclient: trying %s", smtp_url);                           // send the message
 285                         res = curl_easy_perform(curl);
 286                         curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &response_code);
 287                         syslog(LOG_DEBUG, "smtpclient: libcurl returned %d (%s) , SMTP response %ld",
 288                                 res, curl_easy_strerror(res), response_code
 289                         );
 290
 291                         if ((res != CURLE_OK) && (response_code == 0)) {                                // check for errors
 292                                 response_code = 421;
 293                         }
 294
 295                         curl_slist_free_all(recipients);
 296                         recipients = NULL;                                                              // this gets reused; avoid double-free
 297                         curl_easy_cleanup(curl);
 298                         curl = NULL;                                                                    // this gets reused; avoid double-free
 299
 300                         /* Trim the error message buffer down to just the actual message */
 301                         char response_code_str[4];
 302                         snprintf(response_code_str, sizeof response_code_str, "%ld", response_code);
 303                         char *respstart = strstr(response, response_code_str);
 304                         if (respstart == NULL) {
 305                                 strcpy(response, smtpstatus(response_code));
 306                         }
 307                         else {
 308                                 strcpy(response, respstart);
 309                                 char *p;
 310                                 for (p=response; *p!=0; ++p) {
 311                                         if (*p == '\n') *p = ' ';
 312                                         if (*p == '\r') *p = ' ';
 313                                         if (!isprint(*p)) *p = ' ';
 314                                 }
 315                         }
 316                 }
 317         }
 318
 319         FreeStrBuf(&s.TheMessage);
 320         if (fromaddr) free(fromaddr);
 321         return((int)response_code);
 322 }
 323
 324
 325 /*
 326  * Process one outbound message.
 327  */
 328 void smtp_process_one_msg(long qmsgnum)
 329 {
 330         struct CtdlMessage *msg = NULL;
 331         char *instr = NULL;
 332         int i;
 333         int num_success = 0;
 334         int num_fail = 0;
 335         int num_delayed = 0;
 336         long deletes[2];
 337         int delete_this_queue = 0;
 338         char server_response[SIZ];
 339
 340         msg = CtdlFetchMessage(qmsgnum, 1, 1);
 341         if (msg == NULL) {
 342                 syslog(LOG_WARNING, "smtpclient: %ld does not exist", qmsgnum);
 343                 return;
 344         }
 345
 346         instr = msg->cm_fields[eMesageText];
 347         msg->cm_fields[eMesageText] = NULL;
 348         CM_Free(msg);
 349
 350         // if the queue message has any CRLF's convert them to LF's
 351         char *crlf = NULL;
 352         while (crlf = strstr(instr, "\r\n"), crlf != NULL) {
 353                 strcpy(crlf, crlf+1);
 354         }
 355
 356         // Strip out the headers and we are now left with just the instructions.
 357         char *soi = strstr(instr, "\n\n");
 358         if (soi) {
 359                 strcpy(instr, soi+2);
 360         }
 361
 362         long msgid = 0;
 363         time_t submitted = time(NULL);
 364         time_t attempted = 0;
 365         char *bounceto = NULL;
 366         char *envelope_from = NULL;
 367
 368         char cfgline[SIZ];
 369         for (i=0; i<num_tokens(instr, '\n'); ++i) {
 370                 extract_token(cfgline, instr, i, '\n', sizeof cfgline);
 371                 if (!strncasecmp(cfgline, HKEY("msgid|")))              msgid = atol(&cfgline[6]);
 372                 if (!strncasecmp(cfgline, HKEY("submitted|")))          submitted = atol(&cfgline[10]);
 373                 if (!strncasecmp(cfgline, HKEY("attempted|")))          attempted = atol(&cfgline[10]);
 374                 if (!strncasecmp(cfgline, HKEY("bounceto|")))           bounceto = strdup(&cfgline[9]);
 375                 if (!strncasecmp(cfgline, HKEY("envelope_from|")))      envelope_from = strdup(&cfgline[14]);
 376         }
 377
 378         int should_try_now = 0;
 379         if (attempted < submitted) {                            // If no attempts have been made yet, try now
 380                 should_try_now = 1;
 381         }
 382         else if ((attempted - submitted) <= 14400) {
 383                 if ((time(NULL) - attempted) > 1800) {          // First four hours, retry every 30 minutes
 384                         should_try_now = 1;
 385                 }
 386         }
 387         else {
 388                 if ((time(NULL) - attempted) > 14400) {         // After that, retry once every 4 hours
 389                         should_try_now = 1;
 390                 }
 391         }
 392
 393         if (should_try_now) {
 394                 syslog(LOG_DEBUG, "smtpclient: %ld attempting delivery now", qmsgnum);
 395                 StrBuf *NewInstr = NewStrBuf();
 396                 StrBufAppendPrintf(NewInstr, "Content-type: "SPOOLMIME"\n\n");
 397                 StrBufAppendPrintf(NewInstr, "msgid|%ld\n", msgid);
 398                 StrBufAppendPrintf(NewInstr, "submitted|%ld\n", submitted);
 399                 if (bounceto) StrBufAppendPrintf(NewInstr, "bounceto|%s\n", bounceto);
 400                 if (envelope_from) StrBufAppendPrintf(NewInstr, "envelope_from|%s\n", envelope_from);
 401
 402                 for (i=0; i<num_tokens(instr, '\n'); ++i) {
 403                         extract_token(cfgline, instr, i, '\n', sizeof cfgline);
 404                         if (!strncasecmp(cfgline, HKEY("remote|"))) {
 405                                 char recp[SIZ];
 406                                 int previous_result = extract_int(cfgline, 2);
 407                                 if ((previous_result == 0) || (previous_result == 4)) {
 408                                         int new_result = 421;
 409                                         extract_token(recp, cfgline, 1, '|', sizeof recp);
 410                                         new_result = smtp_attempt_delivery(msgid, recp, envelope_from, server_response);
 411                                         syslog(LOG_DEBUG, "smtpclient: recp: <%s> , result: %d (%s)", recp, new_result, server_response);
 412                                         if ((new_result / 100) == 2) {
 413                                                 ++num_success;
 414                                         }
 415                                         else {
 416                                                 if ((new_result / 100) == 5) {
 417                                                         ++num_fail;
 418                                                 }
 419                                                 else {
 420                                                         ++num_delayed;
 421                                                 }
 422                                                 StrBufAppendPrintf(NewInstr, "remote|%s|%ld|%ld (%s)\n",
 423                                                         recp, (new_result / 100) , new_result, server_response
 424                                                 );
 425                                         }
 426                                 }
 427                         }
 428                 }
 429
 430                 StrBufAppendPrintf(NewInstr, "attempted|%ld\n", time(NULL));
 431
 432                 // All deliveries have now been attempted.  Now determine the disposition of this queue entry.
 433
 434                 time_t age = time(NULL) - submitted;
 435                 syslog(LOG_DEBUG, "smtpclient: submission age: %ldd%ldh%ldm%lds", (age/86400) , ((age%86400)/3600) , ((age%3600)/60) , (age%60));
 436                 syslog(LOG_DEBUG, "smtpclient: num_success=%d , num_fail=%d , num_delayed=%d", num_success, num_fail, num_delayed);
 437
 438                 // If there are permanent fails on this attempt, deliver a bounce to the user.
 439                 // The 5XX fails will be recorded in the rewritten queue, but they will be removed before the next attempt.
 440                 if (num_fail > 0) {
 441                         smtp_do_bounce(ChrPtr(NewInstr), SDB_BOUNCE_FATALS);
 442                 }
 443
 444                 // If all deliveries have either succeeded or failed, we are finished with this queue entry.
 445                 //
 446                 if (num_delayed == 0) {
 447                         delete_this_queue = 1;
 448                 }
 449
 450                 // If it's been more than five days, give up and tell the sender that delivery failed
 451                 //
 452                 else if ((time(NULL) - submitted) > SMTP_DELIVER_FAIL) {
 453                         smtp_do_bounce(ChrPtr(NewInstr), SDB_BOUNCE_ALL);
 454                         delete_this_queue = 1;
 455                 }
 456
 457                 // If it's been more than four hours but less than five days, warn the sender that delivery is delayed
 458                 //
 459                 else if ( ((attempted - submitted) < SMTP_DELIVER_WARN) && ((time(NULL) - submitted) >= SMTP_DELIVER_WARN) ) {
 460                         smtp_do_bounce(ChrPtr(NewInstr), SDB_WARN);
 461                 }
 462
 463                 if (delete_this_queue) {
 464                         syslog(LOG_DEBUG, "smtpclient: %ld deleting", qmsgnum);
 465                         deletes[0] = qmsgnum;
 466                         deletes[1] = msgid;
 467                         CtdlDeleteMessages(SMTP_SPOOLOUT_ROOM, deletes, 2, "");
 468                         FreeStrBuf(&NewInstr);                                          // We have to free NewInstr here, no longer needed
 469                 }
 470                 else {
 471                         // replace the old queue entry with the new one
 472                         syslog(LOG_DEBUG, "smtpclient: %ld rewriting", qmsgnum);
 473                         msg = convert_internet_message_buf(&NewInstr);                  // This function will free NewInstr for us
 474                         CtdlSubmitMsg(msg, NULL, SMTP_SPOOLOUT_ROOM, 0);
 475                         CM_Free(msg);
 476                         CtdlDeleteMessages(SMTP_SPOOLOUT_ROOM, &qmsgnum, 1, "");
 477                 }
 478         }
 479         else {
 480                 syslog(LOG_DEBUG, "smtpclient: %ld retry time not reached", qmsgnum);
 481         }
 482
 483         if (bounceto != NULL)           free(bounceto);
 484         if (envelope_from != NULL)      free(envelope_from);
 485         free(instr);
 486 }
 487
 488
 489 /*
 490  * Callback for smtp_do_queue()
 491  */
 492 void smtp_add_msg(long msgnum, void *userdata) {
 493
 494         if (smtpq == NULL) {
 495                 smtpq_count = 0;
 496                 smtpq_alloc = 100;
 497                 smtpq = malloc(smtpq_alloc * sizeof(long));
 498         }
 499
 500         if (smtpq_alloc >= smtpq_count) {
 501                 smtpq_alloc += 100;
 502                 smtpq = realloc(smtpq, (smtpq_alloc * sizeof(long)));
 503         }
 504
 505         smtpq[smtpq_count++] = msgnum;
 506 }
 507
 508
 509 /*
 510  * Run through the queue sending out messages.
 511  */
 512 void smtp_do_queue(void) {
 513         int i = 0;
 514
 515         /*
 516          * This is a simple concurrency check to make sure only one smtpclient
 517          * run is done at a time.  We could do this with a mutex, but since we
 518          * don't really require extremely fine granularity here, we'll do it
 519          * with a static variable instead.
 520          */
 521         if (doing_smtpclient) return;
 522         doing_smtpclient = 1;
 523
 524         syslog(LOG_DEBUG, "smtpclient: start queue run");
 525         pthread_setspecific(MyConKey, (void *)&smtp_client_CC);
 526
 527         if (CtdlGetRoom(&CC->room, SMTP_SPOOLOUT_ROOM) != 0) {
 528                 syslog(LOG_WARNING, "Cannot find room <%s>", SMTP_SPOOLOUT_ROOM);
 529                 doing_smtpclient = 0;
 530                 return;
 531         }
 532
 533         // Put the queue in memory so we can close the db cursor
 534         CtdlForEachMessage(MSGS_ALL, 0L, NULL, SPOOLMIME, NULL, smtp_add_msg, NULL);
 535
 536         // We are ready to run through the queue now.
 537         for (i=0; i<smtpq_count; ++i) {
 538                 smtp_process_one_msg(smtpq[i]);
 539         }
 540
 541         smtpq_count = 0;                // don't free it, we will use this memory on the next run
 542         doing_smtpclient = 0;
 543         syslog(LOG_DEBUG, "smtpclient: end queue run");
 544 }
 545
 546
 547 /*
 548  * Module entry point
 549  */
 550 CTDL_MODULE_INIT(smtpclient)
 551 {
 552         if (!threading)
 553         {
 554                 CtdlFillSystemContext(&smtp_client_CC, "SMTP_Send");
 555                 CtdlRegisterMessageHook(smtp_aftersave, EVT_AFTERSAVE);
 556                 CtdlRegisterSessionHook(smtp_do_queue, EVT_TIMER, PRIO_AGGR + 50);
 557                 smtp_init_spoolout();
 558         }
 559
 560         /* return our module id for the log */
 561         return "smtpclient";
 562 }