2 * Citadel context management stuff.
3 * Here's where we (hopefully) have all the code that manipulates contexts.
5 * Copyright (c) 1987-2020 by the citadel.org team
7 * This program is open source software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License, version 3.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
16 #include "ctdl_module.h"
17 #include "serv_extensions.h"
18 #include "citserver.h"
20 #include "locate_host.h"
25 pthread_key_t MyConKey; /* TSD key for MyContext() */
27 CitContext *ContextList = NULL;
28 time_t last_purge = 0; /* Last dead session purge */
29 int num_sessions = 0; /* Current number of sessions */
32 /* Flag for single user mode */
33 static int want_single_user = 0;
35 /* Try to go single user */
37 int CtdlTrySingleUser(void)
41 begin_critical_section(S_SINGLE_USER);
49 end_critical_section(S_SINGLE_USER);
54 void CtdlEndSingleUser(void)
56 begin_critical_section(S_SINGLE_USER);
58 end_critical_section(S_SINGLE_USER);
62 int CtdlWantSingleUser(void)
64 return want_single_user;
68 int CtdlIsSingleUser(void)
72 /* check for only one context here */
73 if (num_sessions == 1)
81 * Locate a context by its session number and terminate it if the user is able.
82 * User can NOT terminate their current session.
83 * User CAN terminate any other session that has them logged in.
84 * Aide CAN terminate any session except the current one.
86 int CtdlTerminateOtherSession (int session_num)
88 struct CitContext *CCC = CC;
93 if (session_num == CCC->cs_pid) return TERM_NOTALLOWED;
95 aide = ( (CCC->user.axlevel >= AxAideU) || (CCC->internal_pgm) ) ;
97 syslog(LOG_DEBUG, "context: locating session to kill");
98 begin_critical_section(S_SESSION_TABLE);
99 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
100 if (session_num == ccptr->cs_pid) {
102 if ((ccptr->user.usernum == CCC->user.usernum) || aide) {
109 if (((ret & TERM_FOUND) != 0) && ((ret & TERM_ALLOWED) != 0))
111 if (ccptr->user.usernum == CCC->user.usernum)
112 ccptr->kill_me = KILLME_ADMIN_TERMINATE;
114 ccptr->kill_me = KILLME_IDLE;
115 end_critical_section(S_SESSION_TABLE);
118 end_critical_section(S_SESSION_TABLE);
126 * Check to see if the user who we just sent mail to is logged in. If yes,
127 * bump the 'new mail' counter for their session. That enables them to
128 * receive a new mail notification without having to hit the database.
130 void BumpNewMailCounter(long which_user)
132 CtdlBumpNewMailCounter(which_user);
135 void CtdlBumpNewMailCounter(long which_user)
139 begin_critical_section(S_SESSION_TABLE);
141 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
142 if (ptr->user.usernum == which_user) {
147 end_critical_section(S_SESSION_TABLE);
152 * Check to see if a user is currently logged in
153 * Take care with what you do as a result of this test.
154 * The user may not have been logged in when this function was called BUT
155 * because of threading the user might be logged in before you test the result.
157 int CtdlIsUserLoggedIn (char *user_name)
162 begin_critical_section (S_SESSION_TABLE);
163 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
164 if (!strcasecmp(cptr->user.fullname, user_name)) {
169 end_critical_section(S_SESSION_TABLE);
176 * Check to see if a user is currently logged in.
177 * Basically same as CtdlIsUserLoggedIn() but uses the user number instead.
178 * Take care with what you do as a result of this test.
179 * The user may not have been logged in when this function was called BUT
180 * because of threading the user might be logged in before you test the result.
182 int CtdlIsUserLoggedInByNum (long usernum)
187 begin_critical_section(S_SESSION_TABLE);
188 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
189 if (cptr->user.usernum == usernum) {
193 end_critical_section(S_SESSION_TABLE);
200 * Return a pointer to the CitContext structure bound to the thread which
201 * called this function. If there's no such binding (for example, if it's
202 * called by the housekeeper thread) then a generic 'master' CC is returned.
204 * This function is used *VERY* frequently and must be kept small.
206 CitContext *MyContext(void) {
207 register CitContext *c;
208 return ((c = (CitContext *) pthread_getspecific(MyConKey), c == NULL) ? &masterCC : c);
215 * Terminate idle sessions. This function pounds through the session table
216 * comparing the current time to each session's time-of-last-command. If an
217 * idle session is found it is terminated, then the search restarts at the
218 * beginning because the pointer to our place in the list becomes invalid.
220 void terminate_idle_sessions(void)
228 begin_critical_section(S_SESSION_TABLE);
229 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
232 && (CtdlGetConfigLong("c_sleeping") > 0)
233 && (now - (ccptr->lastcmd) > CtdlGetConfigLong("c_sleeping"))
235 if (!ccptr->dont_term) {
236 ccptr->kill_me = KILLME_IDLE;
244 end_critical_section(S_SESSION_TABLE);
246 syslog(LOG_INFO, "context: scheduled %d idle sessions for termination", killed);
248 if (longrunners > 0) {
249 syslog(LOG_INFO, "context: did not terminate %d protected idle sessions", longrunners);
255 * During shutdown, close the sockets of any sessions still connected.
257 void terminate_all_sessions(void)
262 begin_critical_section(S_SESSION_TABLE);
263 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
264 if (ccptr->client_socket != -1)
266 syslog(LOG_INFO, "context: terminate_all_sessions() is murdering %s CC[%d]", ccptr->curr_user, ccptr->cs_pid);
267 close(ccptr->client_socket);
268 ccptr->client_socket = -1;
272 end_critical_section(S_SESSION_TABLE);
274 syslog(LOG_INFO, "context: flushed %d stuck sessions", killed);
281 * Terminate a session.
283 void RemoveContext (CitContext *con)
287 syslog(LOG_ERR, "context: RemoveContext() called with NULL, this should not happen");
290 c = con->ServiceName;
294 syslog(LOG_DEBUG, "context: RemoveContext(%s) session %d", c, con->cs_pid);
296 /* Run any cleanup routines registered by loadable modules.
297 * Note: We have to "become_session()" because the cleanup functions
298 * might make references to "CC" assuming it's the right one.
302 PerformSessionHooks(EVT_STOP);
303 client_close(); /* If the client is still connected, blow 'em away. */
304 become_session(NULL);
306 syslog(LOG_INFO, "context: [%3d]SRV[%s] Session ended.", con->cs_pid, c);
309 * If the client is still connected, blow 'em away.
310 * if the socket is 0 or -1, its already gone or was never there.
312 if (con->client_socket > 0)
314 syslog(LOG_INFO, "context: closing socket %d", con->client_socket);
315 close(con->client_socket);
318 /* If using AUTHMODE_LDAP, free the DN */
323 FreeStrBuf(&con->StatusMessage);
324 FreeStrBuf(&con->MigrateBuf);
325 FreeStrBuf(&con->RecvBuf.Buf);
326 if (con->cached_msglist) {
327 free(con->cached_msglist);
330 syslog(LOG_DEBUG, "context: done with RemoveContext()");
336 * Initialize a new context and place it in the list. The session number
337 * used to be the PID (which is why it's called cs_pid), but that was when we
338 * had one process per session. Now we just assign them sequentially, starting
339 * at 1 (don't change it to 0 because masterCC uses 0).
341 CitContext *CreateNewContext(void) {
344 me = (CitContext *) malloc(sizeof(CitContext));
346 syslog(LOG_ERR, "citserver: malloc() failed: %m");
349 memset(me, 0, sizeof(CitContext));
351 /* Give the context a name. Hopefully makes it easier to track */
352 strcpy (me->user.fullname, "SYS_notauth");
354 /* The new context will be created already in the CON_EXECUTING state
355 * in order to prevent another thread from grabbing it while it's
358 me->state = CON_EXECUTING;
360 * Generate a unique session number and insert this context into
363 me->MigrateBuf = NewStrBuf();
365 me->RecvBuf.Buf = NewStrBuf();
367 me->lastcmd = time(NULL); /* set lastcmd to now to prevent idle timer infanticide TODO: if we have a valid IO, use that to set the timer. */
370 begin_critical_section(S_SESSION_TABLE);
371 me->cs_pid = ++next_pid;
373 me->next = ContextList;
375 if (me->next != NULL) {
379 end_critical_section(S_SESSION_TABLE);
385 * Initialize a new context and place it in the list. The session number
386 * used to be the PID (which is why it's called cs_pid), but that was when we
387 * had one process per session. Now we just assign them sequentially, starting
388 * at 1 (don't change it to 0 because masterCC uses 0).
390 CitContext *CloneContext(CitContext *CloneMe) {
393 me = (CitContext *) malloc(sizeof(CitContext));
395 syslog(LOG_ERR, "citserver: malloc() failed: %m");
398 memcpy(me, CloneMe, sizeof(CitContext));
400 memset(&me->RecvBuf, 0, sizeof(IOBuffer));
401 memset(&me->SendBuf, 0, sizeof(IOBuffer));
402 memset(&me->SBuf, 0, sizeof(IOBuffer));
403 me->MigrateBuf = NULL;
404 me->sMigrateBuf = NULL;
405 me->redirect_buffer = NULL;
410 me->download_fp = NULL;
411 me->upload_fp = NULL;
412 /// TODO: what about the room/user?
414 me->openid_data = NULL;
416 me->session_specific_data = NULL;
420 me->cached_msglist = NULL;
421 me->download_fp = NULL;
422 me->upload_fp = NULL;
423 me->client_socket = 0;
425 me->MigrateBuf = NewStrBuf();
426 me->RecvBuf.Buf = NewStrBuf();
428 begin_critical_section(S_SESSION_TABLE);
430 me->cs_pid = ++next_pid;
432 me->next = ContextList;
433 me->lastcmd = time(NULL); /* set lastcmd to now to prevent idle timer infanticide */
435 if (me->next != NULL) {
440 end_critical_section(S_SESSION_TABLE);
446 * Return an array containing a copy of the context list.
447 * This allows worker threads to perform "for each context" operations without
448 * having to lock and traverse the live list.
450 CitContext *CtdlGetContextArray(int *count)
453 CitContext *nptr, *cptr;
455 nContexts = num_sessions;
456 nptr = malloc(sizeof(CitContext) * nContexts);
461 begin_critical_section(S_SESSION_TABLE);
462 for (cptr = ContextList, i=0; cptr != NULL && i < nContexts; cptr = cptr->next, i++) {
463 memcpy(&nptr[i], cptr, sizeof (CitContext));
465 end_critical_section (S_SESSION_TABLE);
474 * Back-end function for starting a session
476 void begin_session(CitContext *con)
479 * Initialize some variables specific to our context.
482 con->internal_pgm = 0;
483 con->download_fp = NULL;
484 con->upload_fp = NULL;
485 con->cached_msglist = NULL;
486 con->cached_num_msgs = 0;
487 con->FirstExpressMessage = NULL;
489 time(&con->lastidle);
490 strcpy(con->lastcmdname, " ");
491 strcpy(con->cs_clientname, "(unknown)");
492 strcpy(con->curr_user, NLI);
493 *con->cs_clientinfo = '\0';
494 safestrncpy(con->cs_host, CtdlGetConfigStr("c_fqdn"), sizeof con->cs_host);
495 safestrncpy(con->cs_addr, "", sizeof con->cs_addr);
496 con->cs_UDSclientUID = -1;
497 con->cs_host[sizeof con->cs_host - 1] = 0;
498 if (!CC->is_local_client) {
499 locate_host(con->cs_host, sizeof con->cs_host,
500 con->cs_addr, sizeof con->cs_addr,
507 #ifdef HAVE_STRUCT_UCRED
509 /* as http://www.wsinnovations.com/softeng/articles/uds.html told us... */
510 struct ucred credentials;
511 socklen_t ucred_length = sizeof(struct ucred);
513 /*fill in the user data structure */
514 if(getsockopt(con->client_socket, SOL_SOCKET, SO_PEERCRED, &credentials, &ucred_length)) {
515 syslog(LOG_ERR, "context: could obtain credentials from unix domain socket");
519 /* the process ID of the process on the other side of the socket */
520 /* credentials.pid; */
522 /* the effective UID of the process on the other side of the socket */
523 con->cs_UDSclientUID = credentials.uid;
525 /* the effective primary GID of the process on the other side of the socket */
526 /* credentials.gid; */
528 /* To get supplemental groups, we will have to look them up in our account
529 database, after a reverse lookup on the UID to get the account name.
530 We can take this opportunity to check to see if this is a legit account.
532 snprintf(con->cs_clientinfo, sizeof(con->cs_clientinfo),
533 "PID: "F_PID_T"; UID: "F_UID_T"; GID: "F_XPID_T" ",
544 if (((CtdlGetConfigInt("c_maxsessions") > 0)&&(num_sessions > CtdlGetConfigInt("c_maxsessions"))) || CtdlWantSingleUser()) {
548 syslog(LOG_INFO, "context: session (%s) started from %s (%s) uid=%d",
549 con->ServiceName, con->cs_host, con->cs_addr, con->cs_UDSclientUID
552 /* Run any session startup routines registered by loadable modules */
553 PerformSessionHooks(EVT_START);
558 * This function fills in a context and its user field correctly
559 * Then creates/loads that user
561 void CtdlFillSystemContext(CitContext *context, char *name)
566 memset(context, 0, sizeof(CitContext));
567 context->internal_pgm = 1;
569 strcpy (sysname, "SYS_");
570 strcat (sysname, name);
571 len = strlen(sysname);
572 memcpy(context->curr_user, sysname, len + 1);
573 context->client_socket = (-1);
574 context->state = CON_SYS;
575 context->ServiceName = name;
577 /* internal_create_user has the side effect of loading the user regardless of whether they
578 * already existed or needed to be created
580 internal_create_user(sysname, &(context->user), -1) ;
582 /* Check to see if the system user needs upgrading */
583 if (context->user.usernum == 0)
584 { /* old system user with number 0, upgrade it */
585 context->user.usernum = get_new_user_number();
586 syslog(LOG_INFO, "context: upgrading system user \"%s\" from user number 0 to user number %ld", context->user.fullname, context->user.usernum);
587 /* add user to the database */
588 CtdlPutUser(&(context->user));
589 cdb_store(CDB_USERSBYNUMBER, &(context->user.usernum), sizeof(long), context->user.fullname, strlen(context->user.fullname)+1);
595 * Cleanup any contexts that are left lying around
597 void context_cleanup(void)
599 CitContext *ptr = NULL;
600 CitContext *rem = NULL;
603 * Clean up the contexts.
604 * There are no threads so no critical_section stuff is needed.
608 /* We need to update the ContextList because some modules may want to itterate it
609 * Question is should we NULL it before iterating here or should we just keep updating it
610 * as we remove items?
612 * Answer is to NULL it first to prevent modules from doing any actions on the list at all
616 /* Remove the session from the active list */
620 syslog(LOG_DEBUG, "context: context_cleanup() purging session %d", ptr->cs_pid);
630 * Purge all sessions which have the 'kill_me' flag set.
631 * This function has code to prevent it from running more than once every
632 * few seconds, because running it after every single unbind would waste a lot
633 * of CPU time and keep the context list locked too much. To force it to run
634 * anyway, set "force" to nonzero.
636 void dead_session_purge(int force) {
637 CitContext *ptr, *ptr2; /* general-purpose utility pointer */
638 CitContext *rem = NULL; /* list of sessions to be destroyed */
641 if ( (time(NULL) - last_purge) < 5 ) {
642 return; /* Too soon, go away */
647 if (try_critical_section(S_SESSION_TABLE))
655 if ( (ptr2->state == CON_IDLE) && (ptr2->kill_me) ) {
656 /* Remove the session from the active list */
658 ptr2->prev->next = ptr2->next;
661 ContextList = ptr2->next;
664 ptr2->next->prev = ptr2->prev;
668 /* And put it on our to-be-destroyed list */
673 end_critical_section(S_SESSION_TABLE);
675 /* Now that we no longer have the session list locked, we can take
676 * our time and destroy any sessions on the to-be-killed list, which
677 * is allocated privately on this thread's stack.
679 while (rem != NULL) {
680 syslog(LOG_DEBUG, "context: dead_session_purge() purging session %d, reason=%d", rem->cs_pid, rem->kill_me);
693 * masterCC is the context we use when not attached to a session. This
694 * function initializes it.
696 void InitializeMasterCC(void) {
697 memset(&masterCC, 0, sizeof(struct CitContext));
698 masterCC.internal_pgm = 1;
707 * Set the "async waiting" flag for a session, if applicable
709 void set_async_waiting(struct CitContext *ccptr)
711 syslog(LOG_DEBUG, "context: setting async_waiting flag for session %d", ccptr->cs_pid);
712 if (ccptr->is_async) {
713 ccptr->async_waiting++;
714 if (ccptr->state == CON_IDLE) {
715 ccptr->state = CON_READY;
721 CTDL_MODULE_INIT(session)