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. Use, duplication, or disclosure
8 // is subject to the terms of the GNU General Public License, version 3.
9 // The program is distributed without any warranty, expressed or implied.
11 #include "ctdl_module.h"
12 #include "serv_extensions.h"
13 #include "citserver.h"
15 #include "locate_host.h"
20 pthread_key_t MyConKey; /* TSD key for MyContext() */
22 CitContext *ContextList = NULL;
23 time_t last_purge = 0; /* Last dead session purge */
24 int num_sessions = 0; /* Current number of sessions */
27 /* Flag for single user mode */
28 static int want_single_user = 0;
30 /* Try to go single user */
32 int CtdlTrySingleUser(void) {
35 begin_critical_section(S_SINGLE_USER);
43 end_critical_section(S_SINGLE_USER);
48 void CtdlEndSingleUser(void) {
49 begin_critical_section(S_SINGLE_USER);
51 end_critical_section(S_SINGLE_USER);
55 int CtdlWantSingleUser(void) {
56 return want_single_user;
60 int CtdlIsSingleUser(void) {
61 if (want_single_user) {
62 /* check for only one context here */
63 if (num_sessions == 1)
71 * Locate a context by its session number and terminate it if the user is able.
72 * User can NOT terminate their current session.
73 * User CAN terminate any other session that has them logged in.
74 * Aide CAN terminate any session except the current one.
76 int CtdlTerminateOtherSession (int session_num) {
81 if (session_num == CC->cs_pid) return TERM_NOTALLOWED;
83 aide = ( (CC->user.axlevel >= AxAideU) || (CC->internal_pgm) ) ;
85 syslog(LOG_DEBUG, "context: locating session to kill");
86 begin_critical_section(S_SESSION_TABLE);
87 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
88 if (session_num == ccptr->cs_pid) {
90 if ((ccptr->user.usernum == CC->user.usernum) || aide) {
97 if (((ret & TERM_FOUND) != 0) && ((ret & TERM_ALLOWED) != 0))
99 if (ccptr->user.usernum == CC->user.usernum)
100 ccptr->kill_me = KILLME_ADMIN_TERMINATE;
102 ccptr->kill_me = KILLME_IDLE;
103 end_critical_section(S_SESSION_TABLE);
106 end_critical_section(S_SESSION_TABLE);
113 * Check to see if the user who we just sent mail to is logged in. If yes,
114 * bump the 'new mail' counter for their session. That enables them to
115 * receive a new mail notification without having to hit the database.
117 void BumpNewMailCounter(long which_user) {
118 CtdlBumpNewMailCounter(which_user);
122 void CtdlBumpNewMailCounter(long which_user) {
125 begin_critical_section(S_SESSION_TABLE);
127 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
128 if (ptr->user.usernum == which_user) {
133 end_critical_section(S_SESSION_TABLE);
138 * Check to see if a user is currently logged in
139 * Take care with what you do as a result of this test.
140 * The user may not have been logged in when this function was called BUT
141 * because of threading the user might be logged in before you test the result.
143 int CtdlIsUserLoggedIn(char *user_name) {
147 begin_critical_section (S_SESSION_TABLE);
148 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
149 if (!strcasecmp(cptr->user.fullname, user_name)) {
154 end_critical_section(S_SESSION_TABLE);
160 * Check to see if a user is currently logged in.
161 * Basically same as CtdlIsUserLoggedIn() but uses the user number instead.
162 * Take care with what you do as a result of this test.
163 * The user may not have been logged in when this function was called BUT
164 * because of threading the user might be logged in before you test the result.
166 int CtdlIsUserLoggedInByNum (long usernum) {
170 begin_critical_section(S_SESSION_TABLE);
171 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
172 if (cptr->user.usernum == usernum) {
176 end_critical_section(S_SESSION_TABLE);
182 * Return a pointer to the CitContext structure bound to the thread which
183 * called this function. If there's no such binding (for example, if it's
184 * called by the housekeeper thread) then a generic 'master' CC is returned.
186 * This function is used *VERY* frequently and must be kept small.
188 CitContext *MyContext(void) {
189 register CitContext *c;
190 return ((c = (CitContext *) pthread_getspecific(MyConKey), c == NULL) ? &masterCC : c);
195 * Terminate idle sessions. This function pounds through the session table
196 * comparing the current time to each session's time-of-last-command. If an
197 * idle session is found it is terminated, then the search restarts at the
198 * beginning because the pointer to our place in the list becomes invalid.
200 void terminate_idle_sessions(void) {
207 begin_critical_section(S_SESSION_TABLE);
208 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
211 && (CtdlGetConfigLong("c_sleeping") > 0)
212 && (now - (ccptr->lastcmd) > CtdlGetConfigLong("c_sleeping"))
214 if (!ccptr->dont_term) {
215 ccptr->kill_me = KILLME_IDLE;
223 end_critical_section(S_SESSION_TABLE);
225 syslog(LOG_INFO, "context: scheduled %d idle sessions for termination", killed);
227 if (longrunners > 0) {
228 syslog(LOG_INFO, "context: did not terminate %d protected idle sessions", longrunners);
234 * During shutdown, close the sockets of any sessions still connected.
236 void terminate_all_sessions(void) {
240 begin_critical_section(S_SESSION_TABLE);
241 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
242 if (ccptr->client_socket != -1)
244 syslog(LOG_INFO, "context: terminate_all_sessions() is murdering %s CC[%d]", ccptr->curr_user, ccptr->cs_pid);
245 close(ccptr->client_socket);
246 ccptr->client_socket = -1;
250 end_critical_section(S_SESSION_TABLE);
252 syslog(LOG_INFO, "context: flushed %d stuck sessions", killed);
258 * Terminate a session.
260 void RemoveContext (CitContext *con) {
263 syslog(LOG_ERR, "context: RemoveContext() called with NULL, this should not happen");
266 c = con->ServiceName;
270 syslog(LOG_DEBUG, "context: RemoveContext(%s) session %d", c, con->cs_pid);
272 /* Run any cleanup routines registered by loadable modules.
273 * Note: We have to "become_session()" because the cleanup functions
274 * might make references to "CC" assuming it's the right one.
278 PerformSessionHooks(EVT_STOP);
279 client_close(); /* If the client is still connected, blow 'em away. */
280 become_session(NULL);
282 syslog(LOG_INFO, "context: [%3d]SRV[%s] Session ended.", con->cs_pid, c);
285 * If the client is still connected, blow 'em away.
286 * if the socket is 0 or -1, its already gone or was never there.
288 if (con->client_socket > 0) {
289 syslog(LOG_INFO, "context: closing socket %d", con->client_socket);
290 close(con->client_socket);
293 /* If using AUTHMODE_LDAP, free the DN */
298 FreeStrBuf(&con->StatusMessage);
299 FreeStrBuf(&con->MigrateBuf);
300 FreeStrBuf(&con->RecvBuf.Buf);
301 if (con->cached_msglist) {
302 free(con->cached_msglist);
305 syslog(LOG_DEBUG, "context: done with RemoveContext()");
310 * Initialize a new context and place it in the list. The session number
311 * used to be the PID (which is why it's called cs_pid), but that was when we
312 * had one process per session. Now we just assign them sequentially, starting
313 * at 1 (don't change it to 0 because masterCC uses 0).
315 CitContext *CreateNewContext(void) {
318 me = (CitContext *) malloc(sizeof(CitContext));
320 syslog(LOG_ERR, "citserver: malloc() failed: %m");
323 memset(me, 0, sizeof(CitContext));
325 /* Give the context a name. Hopefully makes it easier to track */
326 strcpy (me->user.fullname, "SYS_notauth");
328 /* The new context will be created already in the CON_EXECUTING state
329 * in order to prevent another thread from grabbing it while it's
332 me->state = CON_EXECUTING;
334 * Generate a unique session number and insert this context into
337 me->MigrateBuf = NewStrBuf();
339 me->RecvBuf.Buf = NewStrBuf();
341 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. */
344 begin_critical_section(S_SESSION_TABLE);
345 me->cs_pid = ++next_pid;
347 me->next = ContextList;
349 if (me->next != NULL) {
353 end_critical_section(S_SESSION_TABLE);
359 * Initialize a new context and place it in the list. The session number
360 * used to be the PID (which is why it's called cs_pid), but that was when we
361 * had one process per session. Now we just assign them sequentially, starting
362 * at 1 (don't change it to 0 because masterCC uses 0).
364 CitContext *CloneContext(CitContext *CloneMe) {
367 me = (CitContext *) malloc(sizeof(CitContext));
369 syslog(LOG_ERR, "citserver: malloc() failed: %m");
372 memcpy(me, CloneMe, sizeof(CitContext));
374 memset(&me->RecvBuf, 0, sizeof(IOBuffer));
375 memset(&me->SendBuf, 0, sizeof(IOBuffer));
376 memset(&me->SBuf, 0, sizeof(IOBuffer));
377 me->MigrateBuf = NULL;
378 me->sMigrateBuf = NULL;
379 me->redirect_buffer = NULL;
384 me->download_fp = NULL;
385 me->upload_fp = NULL;
386 /// TODO: what about the room/user?
388 me->openid_data = NULL;
390 me->session_specific_data = NULL;
394 me->cached_msglist = NULL;
395 me->download_fp = NULL;
396 me->upload_fp = NULL;
397 me->client_socket = 0;
399 me->MigrateBuf = NewStrBuf();
400 me->RecvBuf.Buf = NewStrBuf();
402 begin_critical_section(S_SESSION_TABLE);
404 me->cs_pid = ++next_pid;
406 me->next = ContextList;
407 me->lastcmd = time(NULL); /* set lastcmd to now to prevent idle timer infanticide */
409 if (me->next != NULL) {
414 end_critical_section(S_SESSION_TABLE);
420 * Return an array containing a copy of the context list.
421 * This allows worker threads to perform "for each context" operations without
422 * having to lock and traverse the live list.
424 CitContext *CtdlGetContextArray(int *count) {
426 CitContext *nptr, *cptr;
428 nContexts = num_sessions;
429 nptr = malloc(sizeof(CitContext) * nContexts);
434 begin_critical_section(S_SESSION_TABLE);
435 for (cptr = ContextList, i=0; cptr != NULL && i < nContexts; cptr = cptr->next, i++) {
436 memcpy(&nptr[i], cptr, sizeof (CitContext));
438 end_critical_section (S_SESSION_TABLE);
446 * Back-end function for starting a session
448 void begin_session(CitContext *con) {
450 * Initialize some variables specific to our context.
453 con->internal_pgm = 0;
454 con->download_fp = NULL;
455 con->upload_fp = NULL;
456 con->cached_msglist = NULL;
457 con->cached_num_msgs = 0;
458 con->FirstExpressMessage = NULL;
460 time(&con->lastidle);
461 strcpy(con->lastcmdname, " ");
462 strcpy(con->cs_clientname, "(unknown)");
463 strcpy(con->curr_user, NLI);
464 *con->cs_clientinfo = '\0';
465 safestrncpy(con->cs_host, CtdlGetConfigStr("c_fqdn"), sizeof con->cs_host);
466 safestrncpy(con->cs_addr, "", sizeof con->cs_addr);
467 con->cs_UDSclientUID = -1;
468 con->cs_host[sizeof con->cs_host - 1] = 0;
469 if (!CC->is_local_client) {
470 locate_host(con->cs_host, sizeof con->cs_host,
471 con->cs_addr, sizeof con->cs_addr,
478 #ifdef HAVE_STRUCT_UCRED
480 /* as http://www.wsinnovations.com/softeng/articles/uds.html told us... */
481 struct ucred credentials;
482 socklen_t ucred_length = sizeof(struct ucred);
484 /*fill in the user data structure */
485 if(getsockopt(con->client_socket, SOL_SOCKET, SO_PEERCRED, &credentials, &ucred_length)) {
486 syslog(LOG_ERR, "context: could obtain credentials from unix domain socket");
490 /* the process ID of the process on the other side of the socket */
491 /* credentials.pid; */
493 /* the effective UID of the process on the other side of the socket */
494 con->cs_UDSclientUID = credentials.uid;
496 /* the effective primary GID of the process on the other side of the socket */
497 /* credentials.gid; */
499 /* To get supplemental groups, we will have to look them up in our account
500 database, after a reverse lookup on the UID to get the account name.
501 We can take this opportunity to check to see if this is a legit account.
503 snprintf(con->cs_clientinfo, sizeof(con->cs_clientinfo),
504 "PID: "F_PID_T"; UID: "F_UID_T"; GID: "F_XPID_T" ",
515 if (((CtdlGetConfigInt("c_maxsessions") > 0)&&(num_sessions > CtdlGetConfigInt("c_maxsessions"))) || CtdlWantSingleUser()) {
519 syslog(LOG_INFO, "context: session (%s) started from %s (%s) uid=%d",
520 con->ServiceName, con->cs_host, con->cs_addr, con->cs_UDSclientUID
523 /* Run any session startup routines registered by loadable modules */
524 PerformSessionHooks(EVT_START);
529 * This function fills in a context and its user field correctly
530 * Then creates/loads that user
532 void CtdlFillSystemContext(CitContext *context, char *name) {
536 memset(context, 0, sizeof(CitContext));
537 context->internal_pgm = 1;
539 strcpy (sysname, "SYS_");
540 strcat (sysname, name);
541 len = strlen(sysname);
542 memcpy(context->curr_user, sysname, len + 1);
543 context->client_socket = (-1);
544 context->state = CON_SYS;
545 context->ServiceName = name;
547 /* internal_create_user has the side effect of loading the user regardless of whether they
548 * already existed or needed to be created
550 internal_create_user(sysname, &(context->user), -1) ;
552 /* Check to see if the system user needs upgrading */
553 if (context->user.usernum == 0) { /* old system user with number 0, upgrade it */
554 context->user.usernum = get_new_user_number();
555 syslog(LOG_INFO, "context: upgrading system user \"%s\" from user number 0 to user number %ld", context->user.fullname, context->user.usernum);
556 /* add user to the database */
557 CtdlPutUser(&(context->user));
558 cdb_store(CDB_USERSBYNUMBER, &(context->user.usernum), sizeof(long), context->user.fullname, strlen(context->user.fullname)+1);
564 * Cleanup any contexts that are left lying around
566 void context_cleanup(void) {
567 CitContext *ptr = NULL;
568 CitContext *rem = NULL;
571 * Clean up the contexts.
572 * There are no threads so no critical_section stuff is needed.
576 /* We need to update the ContextList because some modules may want to itterate it
577 * Question is should we NULL it before iterating here or should we just keep updating it
578 * as we remove items?
580 * Answer is to NULL it first to prevent modules from doing any actions on the list at all
584 /* Remove the session from the active list */
588 syslog(LOG_DEBUG, "context: context_cleanup() purging session %d", ptr->cs_pid);
597 * Purge all sessions which have the 'kill_me' flag set.
598 * This function has code to prevent it from running more than once every
599 * few seconds, because running it after every single unbind would waste a lot
600 * of CPU time and keep the context list locked too much. To force it to run
601 * anyway, set "force" to nonzero.
603 void dead_session_purge(int force) {
604 CitContext *ptr, *ptr2; /* general-purpose utility pointer */
605 CitContext *rem = NULL; /* list of sessions to be destroyed */
608 if ( (time(NULL) - last_purge) < 5 ) {
609 return; /* Too soon, go away */
614 if (try_critical_section(S_SESSION_TABLE))
622 if ( (ptr2->state == CON_IDLE) && (ptr2->kill_me) ) {
623 /* Remove the session from the active list */
625 ptr2->prev->next = ptr2->next;
628 ContextList = ptr2->next;
631 ptr2->next->prev = ptr2->prev;
635 /* And put it on our to-be-destroyed list */
640 end_critical_section(S_SESSION_TABLE);
642 /* Now that we no longer have the session list locked, we can take
643 * our time and destroy any sessions on the to-be-killed list, which
644 * is allocated privately on this thread's stack.
646 while (rem != NULL) {
647 syslog(LOG_DEBUG, "context: dead_session_purge() purging session %d, reason=%d", rem->cs_pid, rem->kill_me);
657 * masterCC is the context we use when not attached to a session. This
658 * function initializes it.
660 void InitializeMasterCC(void) {
661 memset(&masterCC, 0, sizeof(struct CitContext));
662 masterCC.internal_pgm = 1;
668 * Set the "async waiting" flag for a session, if applicable
670 void set_async_waiting(struct CitContext *ccptr) {
671 syslog(LOG_DEBUG, "context: setting async_waiting flag for session %d", ccptr->cs_pid);
672 if (ccptr->is_async) {
673 ccptr->async_waiting++;
674 if (ccptr->state == CON_IDLE) {
675 ccptr->state = CON_READY;
681 CTDL_MODULE_INIT(session)