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Member "citadel/modules/xmpp/xmpp_presence.c" (5 Jun 2021, 10726 Bytes) of package /linux/www/citadel.tar.gz:


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    1 /*
    2  * Handle XMPP presence exchanges
    3  *
    4  * Copyright (c) 2007-2021 by Art Cancro and citadel.org
    5  *
    6  * This program is open source software; you can redistribute it and/or modify
    7  * it under the terms of the GNU General Public License as published by
    8  * the Free Software Foundation; either version 3 of the License, or
    9  * (at your option) any later version.
   10  *
   11  * This program is distributed in the hope that it will be useful,
   12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   14  * GNU General Public License for more details.
   15  *
   16  * You should have received a copy of the GNU General Public License
   17  * along with this program; if not, write to the Free Software
   18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   19  *
   20  */
   21 
   22 #include "sysdep.h"
   23 #include <stdlib.h>
   24 #include <unistd.h>
   25 #include <stdio.h>
   26 #include <fcntl.h>
   27 #include <signal.h>
   28 #include <pwd.h>
   29 #include <errno.h>
   30 #include <sys/types.h>
   31 #include <assert.h>
   32 #include <time.h>
   33 #include <sys/wait.h>
   34 #include <string.h>
   35 #include <limits.h>
   36 #include <ctype.h>
   37 #include <expat.h>
   38 #include <libcitadel.h>
   39 #include "citadel.h"
   40 #include "server.h"
   41 #include "citserver.h"
   42 #include "support.h"
   43 #include "config.h"
   44 #include "internet_addressing.h"
   45 #include "ctdl_module.h"
   46 #include "serv_xmpp.h"
   47 
   48 
   49 /* 
   50  * Indicate the presence of another user to the client
   51  * (used in several places)
   52  */
   53 void xmpp_indicate_presence(char *presence_jid) {
   54     char xmlbuf[256];
   55 
   56     syslog(LOG_DEBUG, "xmpp: indicating presence of <%s> to <%s>", presence_jid, XMPP->client_jid);
   57     cprintf("<presence from=\"%s\" ", xmlesc(xmlbuf, presence_jid, sizeof xmlbuf));
   58     cprintf("to=\"%s\"></presence>", xmlesc(xmlbuf, XMPP->client_jid, sizeof xmlbuf));
   59 }
   60 
   61 
   62 /*
   63  * Convenience function to determine whether any given session is 'visible' to any other given session,
   64  * and is capable of receiving instant messages from that session.
   65  */
   66 int xmpp_is_visible(struct CitContext *cptr, struct CitContext *to_whom) {
   67     int aide = (to_whom->user.axlevel >= AxAideU);
   68 
   69     if (    (cptr->logged_in)
   70         &&  (((cptr->cs_flags&CS_STEALTH)==0) || (aide))    /* aides see everyone */
   71         &&  (cptr->user.usernum != to_whom->user.usernum)   /* don't show myself */
   72         &&  (cptr->can_receive_im)              /* IM-capable session */
   73     ) {
   74         return(1);
   75     }
   76     else {
   77         return(0);
   78     }
   79 }
   80 
   81 
   82 /* 
   83  * Initial dump of the entire wholist
   84  */
   85 void xmpp_wholist_presence_dump(void) {
   86     struct CitContext *cptr = NULL;
   87     int nContexts, i;
   88     
   89     cptr = CtdlGetContextArray(&nContexts);
   90     if (!cptr) {
   91         return;
   92     }
   93 
   94     for (i=0; i<nContexts; i++) {
   95         if (xmpp_is_visible(&cptr[i], CC)) {
   96             xmpp_indicate_presence(cptr[i].cs_principal_id);
   97         }
   98     }
   99     free(cptr);
  100 }
  101 
  102 
  103 /*
  104  * Function to remove a buddy subscription and delete from the roster
  105  * (used in several places)
  106  */
  107 void xmpp_destroy_buddy(char *presence_jid, int aggressively) {
  108     static int unsolicited_id = 1;
  109     char xmlbuf1[256];
  110     char xmlbuf2[256];
  111 
  112     if (!presence_jid) return;
  113     if (!XMPP) return;
  114     if (!XMPP->client_jid) return;
  115 
  116     /* Transmit non-presence information */
  117     cprintf("<presence type=\"unavailable\" from=\"%s\" to=\"%s\"></presence>",
  118         xmlesc(xmlbuf1, presence_jid, sizeof xmlbuf1),
  119         xmlesc(xmlbuf2, XMPP->client_jid, sizeof xmlbuf2)
  120     );
  121 
  122     /*
  123      * Setting the "aggressively" flag also sends an "unsubscribed" presence update.
  124      * We only ask for this when flushing the client side roster, because if we do it
  125      * in the middle of a session when another user logs off, some clients (Jitsi) interpret
  126      * it as a rejection of a subscription request.
  127      */
  128     if (aggressively) {
  129         cprintf("<presence type=\"unsubscribed\" from=\"%s\" to=\"%s\"></presence>",
  130             xmlesc(xmlbuf1, presence_jid, sizeof xmlbuf1),
  131             xmlesc(xmlbuf2, XMPP->client_jid, sizeof xmlbuf2)
  132         );
  133     }
  134 
  135     // note: we should implement xmpp_indicate_nonpresence so we can use it elsewhere
  136 
  137     /* Do an unsolicited roster update that deletes the contact. */
  138     cprintf("<iq from=\"%s\" to=\"%s\" id=\"unbuddy_%x\" type=\"result\">",
  139         xmlesc(xmlbuf1, CC->cs_principal_id, sizeof xmlbuf1),
  140         xmlesc(xmlbuf2, XMPP->client_jid, sizeof xmlbuf2),
  141         ++unsolicited_id
  142     );
  143     cprintf("<query xmlns=\"jabber:iq:roster\">");
  144     cprintf("<item jid=\"%s\" subscription=\"remove\">", xmlesc(xmlbuf1, presence_jid, sizeof xmlbuf1));
  145     cprintf("<group>%s</group>", xmlesc(xmlbuf1, CtdlGetConfigStr("c_humannode"), sizeof xmlbuf1));
  146     cprintf("</item>");
  147     cprintf("</query>"
  148         "</iq>"
  149     );
  150 }
  151 
  152 
  153 /*
  154  * When a user logs in or out of the local Citadel system, notify all XMPP sessions about it.
  155  * THIS FUNCTION HAS A BUG IN IT THAT ENUMERATES THE SESSIONS WRONG.
  156  */
  157 void xmpp_presence_notify(char *presence_jid, int event_type) {
  158     struct CitContext *cptr;
  159     static int unsolicited_id = 12345;
  160     int visible_sessions = 0;
  161     int nContexts, i;
  162     int which_cptr_is_relevant = (-1);
  163 
  164     if (IsEmptyStr(presence_jid)) return;
  165     if (CC->kill_me) return;
  166 
  167     cptr = CtdlGetContextArray(&nContexts);
  168     if (!cptr) {
  169         return;
  170     }
  171 
  172     /* Count the visible sessions for this user */
  173     for (i=0; i<nContexts; i++) {
  174         if ( (!strcasecmp(cptr[i].cs_principal_id, presence_jid))
  175            && (xmpp_is_visible(&cptr[i], CC))
  176         )  {
  177             ++visible_sessions;
  178             which_cptr_is_relevant = i;
  179         }
  180     }
  181 
  182     syslog(LOG_DEBUG, "xmpp: %d sessions for <%s> are now visible to session %d", visible_sessions, presence_jid, CC->cs_pid);
  183 
  184     if ( (event_type == XMPP_EVT_LOGIN) && (visible_sessions == 1) ) {
  185 
  186         syslog(LOG_DEBUG, "xmpp: telling session %d that <%s> logged in", CC->cs_pid, presence_jid);
  187 
  188         /* Do an unsolicited roster update that adds a new contact. */
  189         assert(which_cptr_is_relevant >= 0);
  190         cprintf("<iq id=\"unsolicited_%x\" type=\"result\">", ++unsolicited_id);
  191         cprintf("<query xmlns=\"jabber:iq:roster\">");
  192         xmpp_roster_item(&cptr[which_cptr_is_relevant]);
  193         cprintf("</query></iq>");
  194 
  195         /* Transmit presence information */
  196         xmpp_indicate_presence(presence_jid);
  197     }
  198 
  199     if (visible_sessions == 0) {
  200         syslog(LOG_DEBUG, "xmpp: telling session %d that <%s> logged out", CC->cs_pid, presence_jid);
  201         xmpp_destroy_buddy(presence_jid, 0);    /* non aggressive presence update */
  202     }
  203 
  204     free(cptr);
  205 }
  206 
  207 
  208 void xmpp_fetch_mortuary_backend(long msgnum, void *userdata) {
  209     HashList *mortuary = (HashList *) userdata;
  210     struct CtdlMessage *msg;
  211     char *ptr = NULL;
  212     char *lasts = NULL;
  213 
  214     msg = CtdlFetchMessage(msgnum, 1);
  215     if (msg == NULL) {
  216         return;
  217     }
  218 
  219     /* now add anyone we find into the hashlist */
  220 
  221     /* skip past the headers */
  222     ptr = strstr(msg->cm_fields[eMesageText], "\n\n");
  223     if (ptr != NULL) {
  224         ptr += 2;
  225     }
  226     else {
  227         ptr = strstr(msg->cm_fields[eMesageText], "\n\r\n");
  228         if (ptr != NULL) {
  229             ptr += 3;
  230         }
  231     }
  232 
  233     /* the remaining lines are addresses */
  234     if (ptr != NULL) {
  235         ptr = strtok_r(ptr, "\n", &lasts);
  236         while (ptr != NULL) {
  237             char *pch = strdup(ptr);
  238             Put(mortuary, pch, strlen(pch), pch, NULL);
  239             ptr = strtok_r(NULL, "\n", &lasts);
  240         }
  241     }
  242 
  243     CM_Free(msg);
  244 }
  245 
  246 
  247 /*
  248  * Fetch the "mortuary" - a list of dead buddies which we keep around forever
  249  * so we can remove them from any client's roster that still has them listed
  250  */
  251 HashList *xmpp_fetch_mortuary(void) {
  252     HashList *mortuary = NewHash(1, NULL);
  253     if (!mortuary) {
  254         syslog(LOG_ALERT, "xmpp: NewHash() failed!");
  255         return(NULL);
  256     }
  257 
  258         if (CtdlGetRoom(&CC->room, USERCONFIGROOM) != 0) {
  259         /* no config room exists - no further processing is required. */
  260                 return(mortuary);
  261         }
  262         CtdlForEachMessage(MSGS_LAST, 1, NULL, XMPPMORTUARY, NULL,
  263                 xmpp_fetch_mortuary_backend, (void *)mortuary );
  264 
  265     return(mortuary);
  266 }
  267 
  268 
  269 /*
  270  * Fetch the "mortuary" - a list of dead buddies which we keep around forever
  271  * so we can remove them from any client's roster that still has them listed
  272  */
  273 void xmpp_store_mortuary(HashList *mortuary) {
  274     HashPos *HashPos;
  275     long len;
  276     void *Value;
  277     const char *Key;
  278     StrBuf *themsg;
  279 
  280     themsg = NewStrBuf();
  281     StrBufPrintf(themsg,    "Content-type: " XMPPMORTUARY "\n"
  282                 "Content-transfer-encoding: 7bit\n"
  283                 "\n"
  284     );
  285 
  286     HashPos = GetNewHashPos(mortuary, 0);
  287     while (GetNextHashPos(mortuary, HashPos, &len, &Key, &Value) != 0) {
  288         StrBufAppendPrintf(themsg, "%s\n", (char *)Value);
  289     }
  290     DeleteHashPos(&HashPos);
  291 
  292     /* Delete the old mortuary */
  293     CtdlDeleteMessages(USERCONFIGROOM, NULL, 0, XMPPMORTUARY);
  294 
  295     /* And save the new one to disk */
  296     quickie_message(CC->user.fullname, NULL, NULL, USERCONFIGROOM, ChrPtr(themsg), 4, "XMPP Mortuary");
  297     FreeStrBuf(&themsg);
  298 }
  299 
  300 
  301 /*
  302  * Upon logout we make an attempt to delete the whole roster, in order to
  303  * try to keep "ghost" buddies from remaining in the client-side roster.
  304  *
  305  * Since the client is probably not still alive, also remember the current
  306  * roster for next time so we can delete dead buddies then.
  307  */
  308 void xmpp_massacre_roster(void) {
  309     struct CitContext *cptr;
  310     int nContexts, i;
  311     HashList *mortuary = xmpp_fetch_mortuary();
  312 
  313     cptr = CtdlGetContextArray(&nContexts);
  314     if (cptr) {
  315         for (i=0; i<nContexts; i++) {
  316             if (xmpp_is_visible(&cptr[i], CC)) {
  317                 if (mortuary) {
  318                     char *buddy = strdup(cptr[i].cs_principal_id);
  319                     Put(mortuary, buddy, strlen(buddy), buddy, NULL);
  320                 }
  321             }
  322         }
  323         free (cptr);
  324     }
  325 
  326     if (mortuary) {
  327         xmpp_store_mortuary(mortuary);
  328         DeleteHash(&mortuary);
  329     }
  330 }
  331 
  332 
  333 /*
  334  * Stupidly, XMPP does not specify a way to tell the client to flush its client-side roster
  335  * and prepare to receive a new one.  So instead we remember every buddy we've ever told the
  336  * client about, and push delete operations out at the beginning of a session.
  337  * 
  338  * We omit any users who happen to be online right now, but we still keep them in the mortuary,
  339  * which needs to be maintained as a list of every buddy the user has ever seen.  We don't know
  340  * when they're connecting from the same client and when they're connecting from a different client,
  341  * so we have no guarantee of what is in the client side roster at connect time.
  342  */
  343 void xmpp_delete_old_buddies_who_no_longer_exist_from_the_client_roster(void) {
  344     long len;
  345     void *Value;
  346     const char *Key;
  347     struct CitContext *cptr;
  348     int nContexts, i;
  349     int online_now = 0;
  350     HashList *mortuary = xmpp_fetch_mortuary();
  351     HashPos *HashPos = GetNewHashPos(mortuary, 0);
  352 
  353     /* we need to omit anyone who is currently online */
  354     cptr = CtdlGetContextArray(&nContexts);
  355 
  356     /* go through the list of users in the mortuary... */
  357     while (GetNextHashPos(mortuary, HashPos, &len, &Key, &Value) != 0)
  358     {
  359 
  360         online_now = 0;
  361         if (cptr) for (i=0; i<nContexts; i++) {
  362             if (xmpp_is_visible(&cptr[i], CC)) {
  363                 if (!strcasecmp(cptr[i].cs_principal_id, (char *)Value)) {
  364                     online_now = 1;
  365                 }
  366             }
  367         }
  368 
  369         if (!online_now) {
  370             xmpp_destroy_buddy((char *)Value, 1);   /* aggressive presence update */
  371         }
  372 
  373     }
  374     DeleteHashPos(&HashPos);
  375     DeleteHash(&mortuary);
  376     free(cptr);
  377 }