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.
10 #include "ctdl_module.h"
11 #include "serv_extensions.h"
12 #include "citserver.h"
14 #include "locate_host.h"
19 pthread_key_t MyConKey; /* TSD key for MyContext() */
21 CitContext *ContextList = NULL;
22 time_t last_purge = 0; /* Last dead session purge */
23 int num_sessions = 0; /* Current number of sessions */
26 /* Flag for single user mode */
27 static int want_single_user = 0;
29 /* Try to go single user */
31 int CtdlTrySingleUser(void) {
34 begin_critical_section(S_SINGLE_USER);
42 end_critical_section(S_SINGLE_USER);
47 void CtdlEndSingleUser(void) {
48 begin_critical_section(S_SINGLE_USER);
50 end_critical_section(S_SINGLE_USER);
54 int CtdlWantSingleUser(void) {
55 return want_single_user;
59 int CtdlIsSingleUser(void) {
60 if (want_single_user) {
61 /* check for only one context here */
62 if (num_sessions == 1)
70 * Locate a context by its session number and terminate it if the user is able.
71 * User can NOT terminate their current session.
72 * User CAN terminate any other session that has them logged in.
73 * Aide CAN terminate any session except the current one.
75 int CtdlTerminateOtherSession (int session_num) {
80 if (session_num == CC->cs_pid) return TERM_NOTALLOWED;
82 aide = ( (CC->user.axlevel >= AxAideU) || (CC->internal_pgm) ) ;
84 syslog(LOG_DEBUG, "context: locating session to kill");
85 begin_critical_section(S_SESSION_TABLE);
86 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
87 if (session_num == ccptr->cs_pid) {
89 if ((ccptr->user.usernum == CC->user.usernum) || aide) {
96 if (((ret & TERM_FOUND) != 0) && ((ret & TERM_ALLOWED) != 0))
98 if (ccptr->user.usernum == CC->user.usernum)
99 ccptr->kill_me = KILLME_ADMIN_TERMINATE;
101 ccptr->kill_me = KILLME_IDLE;
102 end_critical_section(S_SESSION_TABLE);
105 end_critical_section(S_SESSION_TABLE);
112 * Check to see if the user who we just sent mail to is logged in. If yes,
113 * bump the 'new mail' counter for their session. That enables them to
114 * receive a new mail notification without having to hit the database.
116 void BumpNewMailCounter(long which_user) {
117 CtdlBumpNewMailCounter(which_user);
121 void CtdlBumpNewMailCounter(long which_user) {
124 begin_critical_section(S_SESSION_TABLE);
126 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
127 if (ptr->user.usernum == which_user) {
132 end_critical_section(S_SESSION_TABLE);
137 * Check to see if a user is currently logged in
138 * Take care with what you do as a result of this test.
139 * The user may not have been logged in when this function was called BUT
140 * because of threading the user might be logged in before you test the result.
142 int CtdlIsUserLoggedIn(char *user_name) {
146 begin_critical_section (S_SESSION_TABLE);
147 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
148 if (!strcasecmp(cptr->user.fullname, user_name)) {
153 end_critical_section(S_SESSION_TABLE);
159 * Check to see if a user is currently logged in.
160 * Basically same as CtdlIsUserLoggedIn() but uses the user number instead.
161 * Take care with what you do as a result of this test.
162 * The user may not have been logged in when this function was called BUT
163 * because of threading the user might be logged in before you test the result.
165 int CtdlIsUserLoggedInByNum (long usernum) {
169 begin_critical_section(S_SESSION_TABLE);
170 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
171 if (cptr->user.usernum == usernum) {
175 end_critical_section(S_SESSION_TABLE);
181 * Return a pointer to the CitContext structure bound to the thread which
182 * called this function. If there's no such binding (for example, if it's
183 * called by the housekeeper thread) then a generic 'master' CC is returned.
185 * This function is used *VERY* frequently and must be kept small.
187 CitContext *MyContext(void) {
188 register CitContext *c;
189 return ((c = (CitContext *) pthread_getspecific(MyConKey), c == NULL) ? &masterCC : c);
194 * Terminate idle sessions. This function pounds through the session table
195 * comparing the current time to each session's time-of-last-command. If an
196 * idle session is found it is terminated, then the search restarts at the
197 * beginning because the pointer to our place in the list becomes invalid.
199 void terminate_idle_sessions(void) {
206 begin_critical_section(S_SESSION_TABLE);
207 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
210 && (CtdlGetConfigLong("c_sleeping") > 0)
211 && (now - (ccptr->lastcmd) > CtdlGetConfigLong("c_sleeping"))
213 if (!ccptr->dont_term) {
214 ccptr->kill_me = KILLME_IDLE;
222 end_critical_section(S_SESSION_TABLE);
224 syslog(LOG_INFO, "context: scheduled %d idle sessions for termination", killed);
226 if (longrunners > 0) {
227 syslog(LOG_INFO, "context: did not terminate %d protected idle sessions", longrunners);
233 * During shutdown, close the sockets of any sessions still connected.
235 void terminate_all_sessions(void) {
239 begin_critical_section(S_SESSION_TABLE);
240 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
241 if (ccptr->client_socket != -1)
243 syslog(LOG_INFO, "context: terminate_all_sessions() is murdering %s CC[%d]", ccptr->curr_user, ccptr->cs_pid);
244 close(ccptr->client_socket);
245 ccptr->client_socket = -1;
249 end_critical_section(S_SESSION_TABLE);
251 syslog(LOG_INFO, "context: flushed %d stuck sessions", killed);
257 * Terminate a session.
259 void RemoveContext (CitContext *con) {
262 syslog(LOG_ERR, "context: RemoveContext() called with NULL, this should not happen");
265 c = con->ServiceName;
269 syslog(LOG_DEBUG, "context: RemoveContext(%s) session %d", c, con->cs_pid);
271 /* Run any cleanup routines registered by loadable modules.
272 * Note: We have to "become_session()" because the cleanup functions
273 * might make references to "CC" assuming it's the right one.
277 PerformSessionHooks(EVT_STOP);
278 client_close(); /* If the client is still connected, blow 'em away. */
279 become_session(NULL);
281 syslog(LOG_INFO, "context: [%3d]SRV[%s] Session ended.", con->cs_pid, c);
284 * If the client is still connected, blow 'em away.
285 * if the socket is 0 or -1, its already gone or was never there.
287 if (con->client_socket > 0) {
288 syslog(LOG_INFO, "context: closing socket %d", con->client_socket);
289 close(con->client_socket);
292 /* If using AUTHMODE_LDAP, free the DN */
297 FreeStrBuf(&con->StatusMessage);
298 FreeStrBuf(&con->MigrateBuf);
299 FreeStrBuf(&con->RecvBuf.Buf);
300 if (con->cached_msglist) {
301 free(con->cached_msglist);
304 syslog(LOG_DEBUG, "context: done with RemoveContext()");
309 * Initialize a new context and place it in the list. The session number
310 * used to be the PID (which is why it's called cs_pid), but that was when we
311 * had one process per session. Now we just assign them sequentially, starting
312 * at 1 (don't change it to 0 because masterCC uses 0).
314 CitContext *CreateNewContext(void) {
317 me = (CitContext *) malloc(sizeof(CitContext));
319 syslog(LOG_ERR, "citserver: malloc() failed: %m");
322 memset(me, 0, sizeof(CitContext));
324 /* Give the context a name. Hopefully makes it easier to track */
325 strcpy (me->user.fullname, "SYS_notauth");
327 /* The new context will be created already in the CON_EXECUTING state
328 * in order to prevent another thread from grabbing it while it's
331 me->state = CON_EXECUTING;
333 * Generate a unique session number and insert this context into
336 me->MigrateBuf = NewStrBuf();
338 me->RecvBuf.Buf = NewStrBuf();
340 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. */
343 begin_critical_section(S_SESSION_TABLE);
344 me->cs_pid = ++next_pid;
346 me->next = ContextList;
348 if (me->next != NULL) {
352 end_critical_section(S_SESSION_TABLE);
358 * Initialize a new context and place it in the list. The session number
359 * used to be the PID (which is why it's called cs_pid), but that was when we
360 * had one process per session. Now we just assign them sequentially, starting
361 * at 1 (don't change it to 0 because masterCC uses 0).
363 CitContext *CloneContext(CitContext *CloneMe) {
366 me = (CitContext *) malloc(sizeof(CitContext));
368 syslog(LOG_ERR, "citserver: malloc() failed: %m");
371 memcpy(me, CloneMe, sizeof(CitContext));
373 memset(&me->RecvBuf, 0, sizeof(IOBuffer));
374 memset(&me->SendBuf, 0, sizeof(IOBuffer));
375 memset(&me->SBuf, 0, sizeof(IOBuffer));
376 me->MigrateBuf = NULL;
377 me->sMigrateBuf = NULL;
378 me->redirect_buffer = NULL;
383 me->download_fp = NULL;
384 me->upload_fp = NULL;
385 /// TODO: what about the room/user?
387 me->openid_data = NULL;
389 me->session_specific_data = NULL;
393 me->cached_msglist = NULL;
394 me->download_fp = NULL;
395 me->upload_fp = NULL;
396 me->client_socket = 0;
398 me->MigrateBuf = NewStrBuf();
399 me->RecvBuf.Buf = NewStrBuf();
401 begin_critical_section(S_SESSION_TABLE);
403 me->cs_pid = ++next_pid;
405 me->next = ContextList;
406 me->lastcmd = time(NULL); /* set lastcmd to now to prevent idle timer infanticide */
408 if (me->next != NULL) {
413 end_critical_section(S_SESSION_TABLE);
419 * Return an array containing a copy of the context list.
420 * This allows worker threads to perform "for each context" operations without
421 * having to lock and traverse the live list.
423 CitContext *CtdlGetContextArray(int *count) {
425 CitContext *nptr, *cptr;
427 nContexts = num_sessions;
428 nptr = malloc(sizeof(CitContext) * nContexts);
433 begin_critical_section(S_SESSION_TABLE);
434 for (cptr = ContextList, i=0; cptr != NULL && i < nContexts; cptr = cptr->next, i++) {
435 memcpy(&nptr[i], cptr, sizeof (CitContext));
437 end_critical_section (S_SESSION_TABLE);
445 * Back-end function for starting a session
447 void begin_session(CitContext *con) {
449 * Initialize some variables specific to our context.
452 con->internal_pgm = 0;
453 con->download_fp = NULL;
454 con->upload_fp = NULL;
455 con->cached_msglist = NULL;
456 con->cached_num_msgs = 0;
457 con->FirstExpressMessage = NULL;
459 time(&con->lastidle);
460 strcpy(con->lastcmdname, " ");
461 strcpy(con->cs_clientname, "(unknown)");
462 strcpy(con->curr_user, NLI);
463 *con->cs_clientinfo = '\0';
464 safestrncpy(con->cs_host, CtdlGetConfigStr("c_fqdn"), sizeof con->cs_host);
465 safestrncpy(con->cs_addr, "", sizeof con->cs_addr);
466 con->cs_UDSclientUID = -1;
467 con->cs_host[sizeof con->cs_host - 1] = 0;
468 if (!CC->is_local_client) {
469 locate_host(con->cs_host, sizeof con->cs_host,
470 con->cs_addr, sizeof con->cs_addr,
477 #ifdef HAVE_STRUCT_UCRED
479 /* as http://www.wsinnovations.com/softeng/articles/uds.html told us... */
480 struct ucred credentials;
481 socklen_t ucred_length = sizeof(struct ucred);
483 /*fill in the user data structure */
484 if(getsockopt(con->client_socket, SOL_SOCKET, SO_PEERCRED, &credentials, &ucred_length)) {
485 syslog(LOG_ERR, "context: could obtain credentials from unix domain socket");
489 /* the process ID of the process on the other side of the socket */
490 /* credentials.pid; */
492 /* the effective UID of the process on the other side of the socket */
493 con->cs_UDSclientUID = credentials.uid;
495 /* the effective primary GID of the process on the other side of the socket */
496 /* credentials.gid; */
498 /* To get supplemental groups, we will have to look them up in our account
499 database, after a reverse lookup on the UID to get the account name.
500 We can take this opportunity to check to see if this is a legit account.
502 snprintf(con->cs_clientinfo, sizeof(con->cs_clientinfo),
503 "PID: "F_PID_T"; UID: "F_UID_T"; GID: "F_XPID_T" ",
514 if (((CtdlGetConfigInt("c_maxsessions") > 0)&&(num_sessions > CtdlGetConfigInt("c_maxsessions"))) || CtdlWantSingleUser()) {
518 syslog(LOG_INFO, "context: session (%s) started from %s (%s) uid=%d",
519 con->ServiceName, con->cs_host, con->cs_addr, con->cs_UDSclientUID
522 /* Run any session startup routines registered by loadable modules */
523 PerformSessionHooks(EVT_START);
528 * This function fills in a context and its user field correctly
529 * Then creates/loads that user
531 void CtdlFillSystemContext(CitContext *context, char *name) {
535 memset(context, 0, sizeof(CitContext));
536 context->internal_pgm = 1;
538 strcpy (sysname, "SYS_");
539 strcat (sysname, name);
540 len = strlen(sysname);
541 memcpy(context->curr_user, sysname, len + 1);
542 context->client_socket = (-1);
543 context->state = CON_SYS;
544 context->ServiceName = name;
546 /* internal_create_user has the side effect of loading the user regardless of whether they
547 * already existed or needed to be created
549 internal_create_user(sysname, &(context->user), -1) ;
551 /* Check to see if the system user needs upgrading */
552 if (context->user.usernum == 0) { /* old system user with number 0, upgrade it */
553 context->user.usernum = get_new_user_number();
554 syslog(LOG_INFO, "context: upgrading system user \"%s\" from user number 0 to user number %ld", context->user.fullname, context->user.usernum);
555 /* add user to the database */
556 CtdlPutUser(&(context->user));
557 cdb_store(CDB_USERSBYNUMBER, &(context->user.usernum), sizeof(long), context->user.fullname, strlen(context->user.fullname)+1);
563 * Cleanup any contexts that are left lying around
565 void context_cleanup(void) {
566 CitContext *ptr = NULL;
567 CitContext *rem = NULL;
570 * Clean up the contexts.
571 * There are no threads so no critical_section stuff is needed.
575 /* We need to update the ContextList because some modules may want to itterate it
576 * Question is should we NULL it before iterating here or should we just keep updating it
577 * as we remove items?
579 * Answer is to NULL it first to prevent modules from doing any actions on the list at all
583 /* Remove the session from the active list */
587 syslog(LOG_DEBUG, "context: context_cleanup() purging session %d", ptr->cs_pid);
596 * Purge all sessions which have the 'kill_me' flag set.
597 * This function has code to prevent it from running more than once every
598 * few seconds, because running it after every single unbind would waste a lot
599 * of CPU time and keep the context list locked too much. To force it to run
600 * anyway, set "force" to nonzero.
602 void dead_session_purge(int force) {
603 CitContext *ptr, *ptr2; /* general-purpose utility pointer */
604 CitContext *rem = NULL; /* list of sessions to be destroyed */
607 if ( (time(NULL) - last_purge) < 5 ) {
608 return; /* Too soon, go away */
613 if (try_critical_section(S_SESSION_TABLE))
621 if ( (ptr2->state == CON_IDLE) && (ptr2->kill_me) ) {
622 /* Remove the session from the active list */
624 ptr2->prev->next = ptr2->next;
627 ContextList = ptr2->next;
630 ptr2->next->prev = ptr2->prev;
634 /* And put it on our to-be-destroyed list */
639 end_critical_section(S_SESSION_TABLE);
641 /* Now that we no longer have the session list locked, we can take
642 * our time and destroy any sessions on the to-be-killed list, which
643 * is allocated privately on this thread's stack.
645 while (rem != NULL) {
646 syslog(LOG_DEBUG, "context: dead_session_purge() purging session %d, reason=%d", rem->cs_pid, rem->kill_me);
656 * masterCC is the context we use when not attached to a session. This
657 * function initializes it.
659 void InitializeMasterCC(void) {
660 memset(&masterCC, 0, sizeof(struct CitContext));
661 masterCC.internal_pgm = 1;
667 * Set the "async waiting" flag for a session, if applicable
669 void set_async_waiting(struct CitContext *ccptr) {
670 syslog(LOG_DEBUG, "context: setting async_waiting flag for session %d", ccptr->cs_pid);
671 if (ccptr->is_async) {
672 ccptr->async_waiting++;
673 if (ccptr->state == CON_IDLE) {
674 ccptr->state = CON_READY;
680 CTDL_MODULE_INIT(session)