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)
36 begin_critical_section(S_SINGLE_USER);
44 end_critical_section(S_SINGLE_USER);
49 void CtdlEndSingleUser(void)
51 begin_critical_section(S_SINGLE_USER);
53 end_critical_section(S_SINGLE_USER);
57 int CtdlWantSingleUser(void)
59 return want_single_user;
63 int CtdlIsSingleUser(void)
67 /* check for only one context here */
68 if (num_sessions == 1)
76 * Locate a context by its session number and terminate it if the user is able.
77 * User can NOT terminate their current session.
78 * User CAN terminate any other session that has them logged in.
79 * Aide CAN terminate any session except the current one.
81 int CtdlTerminateOtherSession (int session_num)
83 struct CitContext *CCC = CC;
88 if (session_num == CCC->cs_pid) return TERM_NOTALLOWED;
90 aide = ( (CCC->user.axlevel >= AxAideU) || (CCC->internal_pgm) ) ;
92 syslog(LOG_DEBUG, "context: locating session to kill");
93 begin_critical_section(S_SESSION_TABLE);
94 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
95 if (session_num == ccptr->cs_pid) {
97 if ((ccptr->user.usernum == CCC->user.usernum) || aide) {
104 if (((ret & TERM_FOUND) != 0) && ((ret & TERM_ALLOWED) != 0))
106 if (ccptr->user.usernum == CCC->user.usernum)
107 ccptr->kill_me = KILLME_ADMIN_TERMINATE;
109 ccptr->kill_me = KILLME_IDLE;
110 end_critical_section(S_SESSION_TABLE);
113 end_critical_section(S_SESSION_TABLE);
121 * Check to see if the user who we just sent mail to is logged in. If yes,
122 * bump the 'new mail' counter for their session. That enables them to
123 * receive a new mail notification without having to hit the database.
125 void BumpNewMailCounter(long which_user)
127 CtdlBumpNewMailCounter(which_user);
130 void CtdlBumpNewMailCounter(long which_user)
134 begin_critical_section(S_SESSION_TABLE);
136 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
137 if (ptr->user.usernum == which_user) {
142 end_critical_section(S_SESSION_TABLE);
147 * Check to see if a user is currently logged in
148 * Take care with what you do as a result of this test.
149 * The user may not have been logged in when this function was called BUT
150 * because of threading the user might be logged in before you test the result.
152 int CtdlIsUserLoggedIn (char *user_name)
157 begin_critical_section (S_SESSION_TABLE);
158 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
159 if (!strcasecmp(cptr->user.fullname, user_name)) {
164 end_critical_section(S_SESSION_TABLE);
171 * Check to see if a user is currently logged in.
172 * Basically same as CtdlIsUserLoggedIn() but uses the user number instead.
173 * Take care with what you do as a result of this test.
174 * The user may not have been logged in when this function was called BUT
175 * because of threading the user might be logged in before you test the result.
177 int CtdlIsUserLoggedInByNum (long usernum)
182 begin_critical_section(S_SESSION_TABLE);
183 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
184 if (cptr->user.usernum == usernum) {
188 end_critical_section(S_SESSION_TABLE);
195 * Return a pointer to the CitContext structure bound to the thread which
196 * called this function. If there's no such binding (for example, if it's
197 * called by the housekeeper thread) then a generic 'master' CC is returned.
199 * This function is used *VERY* frequently and must be kept small.
201 CitContext *MyContext(void) {
202 register CitContext *c;
203 return ((c = (CitContext *) pthread_getspecific(MyConKey), c == NULL) ? &masterCC : c);
210 * Terminate idle sessions. This function pounds through the session table
211 * comparing the current time to each session's time-of-last-command. If an
212 * idle session is found it is terminated, then the search restarts at the
213 * beginning because the pointer to our place in the list becomes invalid.
215 void terminate_idle_sessions(void)
223 begin_critical_section(S_SESSION_TABLE);
224 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
227 && (CtdlGetConfigLong("c_sleeping") > 0)
228 && (now - (ccptr->lastcmd) > CtdlGetConfigLong("c_sleeping"))
230 if (!ccptr->dont_term) {
231 ccptr->kill_me = KILLME_IDLE;
239 end_critical_section(S_SESSION_TABLE);
241 syslog(LOG_INFO, "context: scheduled %d idle sessions for termination", killed);
243 if (longrunners > 0) {
244 syslog(LOG_INFO, "context: did not terminate %d protected idle sessions", longrunners);
250 * During shutdown, close the sockets of any sessions still connected.
252 void terminate_all_sessions(void)
257 begin_critical_section(S_SESSION_TABLE);
258 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
259 if (ccptr->client_socket != -1)
261 syslog(LOG_INFO, "context: terminate_all_sessions() is murdering %s CC[%d]", ccptr->curr_user, ccptr->cs_pid);
262 close(ccptr->client_socket);
263 ccptr->client_socket = -1;
267 end_critical_section(S_SESSION_TABLE);
269 syslog(LOG_INFO, "context: flushed %d stuck sessions", killed);
276 * Terminate a session.
278 void RemoveContext (CitContext *con)
282 syslog(LOG_ERR, "context: RemoveContext() called with NULL, this should not happen");
285 c = con->ServiceName;
289 syslog(LOG_DEBUG, "context: RemoveContext(%s) session %d", c, con->cs_pid);
291 /* Run any cleanup routines registered by loadable modules.
292 * Note: We have to "become_session()" because the cleanup functions
293 * might make references to "CC" assuming it's the right one.
297 PerformSessionHooks(EVT_STOP);
298 client_close(); /* If the client is still connected, blow 'em away. */
299 become_session(NULL);
301 syslog(LOG_INFO, "context: [%3d]SRV[%s] Session ended.", con->cs_pid, c);
304 * If the client is still connected, blow 'em away.
305 * if the socket is 0 or -1, its already gone or was never there.
307 if (con->client_socket > 0)
309 syslog(LOG_INFO, "context: closing socket %d", con->client_socket);
310 close(con->client_socket);
313 /* If using AUTHMODE_LDAP, free the DN */
318 FreeStrBuf(&con->StatusMessage);
319 FreeStrBuf(&con->MigrateBuf);
320 FreeStrBuf(&con->RecvBuf.Buf);
321 if (con->cached_msglist) {
322 free(con->cached_msglist);
325 syslog(LOG_DEBUG, "context: done with RemoveContext()");
331 * Initialize a new context and place it in the list. The session number
332 * used to be the PID (which is why it's called cs_pid), but that was when we
333 * had one process per session. Now we just assign them sequentially, starting
334 * at 1 (don't change it to 0 because masterCC uses 0).
336 CitContext *CreateNewContext(void) {
339 me = (CitContext *) malloc(sizeof(CitContext));
341 syslog(LOG_ERR, "citserver: malloc() failed: %m");
344 memset(me, 0, sizeof(CitContext));
346 /* Give the context a name. Hopefully makes it easier to track */
347 strcpy (me->user.fullname, "SYS_notauth");
349 /* The new context will be created already in the CON_EXECUTING state
350 * in order to prevent another thread from grabbing it while it's
353 me->state = CON_EXECUTING;
355 * Generate a unique session number and insert this context into
358 me->MigrateBuf = NewStrBuf();
360 me->RecvBuf.Buf = NewStrBuf();
362 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. */
365 begin_critical_section(S_SESSION_TABLE);
366 me->cs_pid = ++next_pid;
368 me->next = ContextList;
370 if (me->next != NULL) {
374 end_critical_section(S_SESSION_TABLE);
380 * Initialize a new context and place it in the list. The session number
381 * used to be the PID (which is why it's called cs_pid), but that was when we
382 * had one process per session. Now we just assign them sequentially, starting
383 * at 1 (don't change it to 0 because masterCC uses 0).
385 CitContext *CloneContext(CitContext *CloneMe) {
388 me = (CitContext *) malloc(sizeof(CitContext));
390 syslog(LOG_ERR, "citserver: malloc() failed: %m");
393 memcpy(me, CloneMe, sizeof(CitContext));
395 memset(&me->RecvBuf, 0, sizeof(IOBuffer));
396 memset(&me->SendBuf, 0, sizeof(IOBuffer));
397 memset(&me->SBuf, 0, sizeof(IOBuffer));
398 me->MigrateBuf = NULL;
399 me->sMigrateBuf = NULL;
400 me->redirect_buffer = NULL;
405 me->download_fp = NULL;
406 me->upload_fp = NULL;
407 /// TODO: what about the room/user?
409 me->openid_data = NULL;
411 me->session_specific_data = NULL;
415 me->cached_msglist = NULL;
416 me->download_fp = NULL;
417 me->upload_fp = NULL;
418 me->client_socket = 0;
420 me->MigrateBuf = NewStrBuf();
421 me->RecvBuf.Buf = NewStrBuf();
423 begin_critical_section(S_SESSION_TABLE);
425 me->cs_pid = ++next_pid;
427 me->next = ContextList;
428 me->lastcmd = time(NULL); /* set lastcmd to now to prevent idle timer infanticide */
430 if (me->next != NULL) {
435 end_critical_section(S_SESSION_TABLE);
441 * Return an array containing a copy of the context list.
442 * This allows worker threads to perform "for each context" operations without
443 * having to lock and traverse the live list.
445 CitContext *CtdlGetContextArray(int *count)
448 CitContext *nptr, *cptr;
450 nContexts = num_sessions;
451 nptr = malloc(sizeof(CitContext) * nContexts);
456 begin_critical_section(S_SESSION_TABLE);
457 for (cptr = ContextList, i=0; cptr != NULL && i < nContexts; cptr = cptr->next, i++) {
458 memcpy(&nptr[i], cptr, sizeof (CitContext));
460 end_critical_section (S_SESSION_TABLE);
469 * Back-end function for starting a session
471 void begin_session(CitContext *con)
474 * Initialize some variables specific to our context.
477 con->internal_pgm = 0;
478 con->download_fp = NULL;
479 con->upload_fp = NULL;
480 con->cached_msglist = NULL;
481 con->cached_num_msgs = 0;
482 con->FirstExpressMessage = NULL;
484 time(&con->lastidle);
485 strcpy(con->lastcmdname, " ");
486 strcpy(con->cs_clientname, "(unknown)");
487 strcpy(con->curr_user, NLI);
488 *con->cs_clientinfo = '\0';
489 safestrncpy(con->cs_host, CtdlGetConfigStr("c_fqdn"), sizeof con->cs_host);
490 safestrncpy(con->cs_addr, "", sizeof con->cs_addr);
491 con->cs_UDSclientUID = -1;
492 con->cs_host[sizeof con->cs_host - 1] = 0;
493 if (!CC->is_local_client) {
494 locate_host(con->cs_host, sizeof con->cs_host,
495 con->cs_addr, sizeof con->cs_addr,
502 #ifdef HAVE_STRUCT_UCRED
504 /* as http://www.wsinnovations.com/softeng/articles/uds.html told us... */
505 struct ucred credentials;
506 socklen_t ucred_length = sizeof(struct ucred);
508 /*fill in the user data structure */
509 if(getsockopt(con->client_socket, SOL_SOCKET, SO_PEERCRED, &credentials, &ucred_length)) {
510 syslog(LOG_ERR, "context: could obtain credentials from unix domain socket");
514 /* the process ID of the process on the other side of the socket */
515 /* credentials.pid; */
517 /* the effective UID of the process on the other side of the socket */
518 con->cs_UDSclientUID = credentials.uid;
520 /* the effective primary GID of the process on the other side of the socket */
521 /* credentials.gid; */
523 /* To get supplemental groups, we will have to look them up in our account
524 database, after a reverse lookup on the UID to get the account name.
525 We can take this opportunity to check to see if this is a legit account.
527 snprintf(con->cs_clientinfo, sizeof(con->cs_clientinfo),
528 "PID: "F_PID_T"; UID: "F_UID_T"; GID: "F_XPID_T" ",
539 if (((CtdlGetConfigInt("c_maxsessions") > 0)&&(num_sessions > CtdlGetConfigInt("c_maxsessions"))) || CtdlWantSingleUser()) {
543 syslog(LOG_INFO, "context: session (%s) started from %s (%s) uid=%d",
544 con->ServiceName, con->cs_host, con->cs_addr, con->cs_UDSclientUID
547 /* Run any session startup routines registered by loadable modules */
548 PerformSessionHooks(EVT_START);
553 * This function fills in a context and its user field correctly
554 * Then creates/loads that user
556 void CtdlFillSystemContext(CitContext *context, char *name)
561 memset(context, 0, sizeof(CitContext));
562 context->internal_pgm = 1;
564 strcpy (sysname, "SYS_");
565 strcat (sysname, name);
566 len = strlen(sysname);
567 memcpy(context->curr_user, sysname, len + 1);
568 context->client_socket = (-1);
569 context->state = CON_SYS;
570 context->ServiceName = name;
572 /* internal_create_user has the side effect of loading the user regardless of whether they
573 * already existed or needed to be created
575 internal_create_user(sysname, &(context->user), -1) ;
577 /* Check to see if the system user needs upgrading */
578 if (context->user.usernum == 0)
579 { /* old system user with number 0, upgrade it */
580 context->user.usernum = get_new_user_number();
581 syslog(LOG_INFO, "context: upgrading system user \"%s\" from user number 0 to user number %ld", context->user.fullname, context->user.usernum);
582 /* add user to the database */
583 CtdlPutUser(&(context->user));
584 cdb_store(CDB_USERSBYNUMBER, &(context->user.usernum), sizeof(long), context->user.fullname, strlen(context->user.fullname)+1);
590 * Cleanup any contexts that are left lying around
592 void context_cleanup(void)
594 CitContext *ptr = NULL;
595 CitContext *rem = NULL;
598 * Clean up the contexts.
599 * There are no threads so no critical_section stuff is needed.
603 /* We need to update the ContextList because some modules may want to itterate it
604 * Question is should we NULL it before iterating here or should we just keep updating it
605 * as we remove items?
607 * Answer is to NULL it first to prevent modules from doing any actions on the list at all
611 /* Remove the session from the active list */
615 syslog(LOG_DEBUG, "context: context_cleanup() purging session %d", ptr->cs_pid);
625 * Purge all sessions which have the 'kill_me' flag set.
626 * This function has code to prevent it from running more than once every
627 * few seconds, because running it after every single unbind would waste a lot
628 * of CPU time and keep the context list locked too much. To force it to run
629 * anyway, set "force" to nonzero.
631 void dead_session_purge(int force) {
632 CitContext *ptr, *ptr2; /* general-purpose utility pointer */
633 CitContext *rem = NULL; /* list of sessions to be destroyed */
636 if ( (time(NULL) - last_purge) < 5 ) {
637 return; /* Too soon, go away */
642 if (try_critical_section(S_SESSION_TABLE))
650 if ( (ptr2->state == CON_IDLE) && (ptr2->kill_me) ) {
651 /* Remove the session from the active list */
653 ptr2->prev->next = ptr2->next;
656 ContextList = ptr2->next;
659 ptr2->next->prev = ptr2->prev;
663 /* And put it on our to-be-destroyed list */
668 end_critical_section(S_SESSION_TABLE);
670 /* Now that we no longer have the session list locked, we can take
671 * our time and destroy any sessions on the to-be-killed list, which
672 * is allocated privately on this thread's stack.
674 while (rem != NULL) {
675 syslog(LOG_DEBUG, "context: dead_session_purge() purging session %d, reason=%d", rem->cs_pid, rem->kill_me);
688 * masterCC is the context we use when not attached to a session. This
689 * function initializes it.
691 void InitializeMasterCC(void) {
692 memset(&masterCC, 0, sizeof(struct CitContext));
693 masterCC.internal_pgm = 1;
702 * Set the "async waiting" flag for a session, if applicable
704 void set_async_waiting(struct CitContext *ccptr)
706 syslog(LOG_DEBUG, "context: setting async_waiting flag for session %d", ccptr->cs_pid);
707 if (ccptr->is_async) {
708 ccptr->async_waiting++;
709 if (ccptr->state == CON_IDLE) {
710 ccptr->state = CON_READY;
716 CTDL_MODULE_INIT(session)