2 // Citadel context management stuff.
3 // Here's where we (hopefully) have all the code that manipulates contexts.
5 // Copyright (c) 1987-2022 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);
35 if (want_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)) {
97 if (ccptr->user.usernum == CC->user.usernum) {
98 ccptr->kill_me = KILLME_ADMIN_TERMINATE;
101 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.
116 void CtdlBumpNewMailCounter(long which_user) {
119 begin_critical_section(S_SESSION_TABLE);
121 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
122 if (ptr->user.usernum == which_user) {
127 end_critical_section(S_SESSION_TABLE);
132 * Check to see if a user is currently logged in
133 * Take care with what you do as a result of this test.
134 * The user may not have been logged in when this function was called BUT
135 * because of threading the user might be logged in before you test the result.
137 int CtdlIsUserLoggedIn(char *user_name) {
141 begin_critical_section (S_SESSION_TABLE);
142 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
143 if (!strcasecmp(cptr->user.fullname, user_name)) {
148 end_critical_section(S_SESSION_TABLE);
154 * Check to see if a user is currently logged in.
155 * Basically same as CtdlIsUserLoggedIn() but uses the user number instead.
156 * Take care with what you do as a result of this test.
157 * The user may not have been logged in when this function was called BUT
158 * because of threading the user might be logged in before you test the result.
160 int CtdlIsUserLoggedInByNum (long usernum) {
164 begin_critical_section(S_SESSION_TABLE);
165 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
166 if (cptr->user.usernum == usernum) {
170 end_critical_section(S_SESSION_TABLE);
176 * Return a pointer to the CitContext structure bound to the thread which
177 * called this function. If there's no such binding (for example, if it's
178 * called by the housekeeper thread) then a generic 'master' CC is returned.
180 * This function is used *VERY* frequently and must be kept small.
182 CitContext *MyContext(void) {
183 register CitContext *c;
184 return ((c = (CitContext *) pthread_getspecific(MyConKey), c == NULL) ? &masterCC : c);
189 * Terminate idle sessions. This function pounds through the session table
190 * comparing the current time to each session's time-of-last-command. If an
191 * idle session is found it is terminated, then the search restarts at the
192 * beginning because the pointer to our place in the list becomes invalid.
194 void terminate_idle_sessions(void) {
201 begin_critical_section(S_SESSION_TABLE);
202 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
205 && (CtdlGetConfigLong("c_sleeping") > 0)
206 && (now - (ccptr->lastcmd) > CtdlGetConfigLong("c_sleeping"))
208 if (!ccptr->dont_term) {
209 ccptr->kill_me = KILLME_IDLE;
217 end_critical_section(S_SESSION_TABLE);
219 syslog(LOG_INFO, "context: scheduled %d idle sessions for termination", killed);
221 if (longrunners > 0) {
222 syslog(LOG_INFO, "context: did not terminate %d protected idle sessions", longrunners);
228 * During shutdown, close the sockets of any sessions still connected.
230 void terminate_all_sessions(void) {
234 begin_critical_section(S_SESSION_TABLE);
235 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
236 if (ccptr->client_socket != -1)
238 syslog(LOG_INFO, "context: terminate_all_sessions() is murdering %s CC[%d]", ccptr->curr_user, ccptr->cs_pid);
239 close(ccptr->client_socket);
240 ccptr->client_socket = -1;
244 end_critical_section(S_SESSION_TABLE);
246 syslog(LOG_INFO, "context: flushed %d stuck sessions", killed);
252 * Terminate a session.
254 void RemoveContext (CitContext *con) {
257 syslog(LOG_ERR, "context: RemoveContext() called with NULL, this should not happen");
260 c = con->ServiceName;
264 syslog(LOG_DEBUG, "context: RemoveContext(%s) session %d", c, con->cs_pid);
266 /* Run any cleanup routines registered by loadable modules.
267 * Note: We have to "become_session()" because the cleanup functions
268 * might make references to "CC" assuming it's the right one.
272 PerformSessionHooks(EVT_STOP);
273 client_close(); /* If the client is still connected, blow 'em away. */
274 become_session(NULL);
276 syslog(LOG_INFO, "context: [%3d]SRV[%s] Session ended.", con->cs_pid, c);
279 * If the client is still connected, blow 'em away.
280 * if the socket is 0 or -1, its already gone or was never there.
282 if (con->client_socket > 0) {
283 syslog(LOG_INFO, "context: closing socket %d", con->client_socket);
284 close(con->client_socket);
287 /* If using AUTHMODE_LDAP, free the DN */
292 FreeStrBuf(&con->StatusMessage);
293 FreeStrBuf(&con->MigrateBuf);
294 FreeStrBuf(&con->RecvBuf.Buf);
295 if (con->cached_msglist) {
296 free(con->cached_msglist);
299 syslog(LOG_DEBUG, "context: done with RemoveContext()");
304 * Initialize a new context and place it in the list. The session number
305 * used to be the PID (which is why it's called cs_pid), but that was when we
306 * had one process per session. Now we just assign them sequentially, starting
307 * at 1 (don't change it to 0 because masterCC uses 0).
309 CitContext *CreateNewContext(void) {
312 me = (CitContext *) malloc(sizeof(CitContext));
314 syslog(LOG_ERR, "citserver: malloc() failed: %m");
317 memset(me, 0, sizeof(CitContext));
319 /* Give the context a name. Hopefully makes it easier to track */
320 strcpy (me->user.fullname, "SYS_notauth");
322 /* The new context will be created already in the CON_EXECUTING state
323 * in order to prevent another thread from grabbing it while it's
326 me->state = CON_EXECUTING;
328 * Generate a unique session number and insert this context into
331 me->MigrateBuf = NewStrBuf();
333 me->RecvBuf.Buf = NewStrBuf();
335 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. */
338 begin_critical_section(S_SESSION_TABLE);
339 me->cs_pid = ++next_pid;
341 me->next = ContextList;
343 if (me->next != NULL) {
347 end_critical_section(S_SESSION_TABLE);
353 * Initialize a new context and place it in the list. The session number
354 * used to be the PID (which is why it's called cs_pid), but that was when we
355 * had one process per session. Now we just assign them sequentially, starting
356 * at 1 (don't change it to 0 because masterCC uses 0).
358 CitContext *CloneContext(CitContext *CloneMe) {
361 me = (CitContext *) malloc(sizeof(CitContext));
363 syslog(LOG_ERR, "citserver: malloc() failed: %m");
366 memcpy(me, CloneMe, sizeof(CitContext));
368 memset(&me->RecvBuf, 0, sizeof(IOBuffer));
369 memset(&me->SendBuf, 0, sizeof(IOBuffer));
370 memset(&me->SBuf, 0, sizeof(IOBuffer));
371 me->MigrateBuf = NULL;
372 me->sMigrateBuf = NULL;
373 me->redirect_buffer = NULL;
378 me->download_fp = NULL;
379 me->upload_fp = NULL;
380 /// TODO: what about the room/user?
382 me->openid_data = NULL;
384 me->session_specific_data = NULL;
388 me->cached_msglist = NULL;
389 me->download_fp = NULL;
390 me->upload_fp = NULL;
391 me->client_socket = 0;
393 me->MigrateBuf = NewStrBuf();
394 me->RecvBuf.Buf = NewStrBuf();
396 begin_critical_section(S_SESSION_TABLE);
398 me->cs_pid = ++next_pid;
400 me->next = ContextList;
401 me->lastcmd = time(NULL); /* set lastcmd to now to prevent idle timer infanticide */
403 if (me->next != NULL) {
408 end_critical_section(S_SESSION_TABLE);
414 * Return an array containing a copy of the context list.
415 * This allows worker threads to perform "for each context" operations without
416 * having to lock and traverse the live list.
418 CitContext *CtdlGetContextArray(int *count) {
420 CitContext *nptr, *cptr;
422 nContexts = num_sessions;
423 nptr = malloc(sizeof(CitContext) * nContexts);
428 begin_critical_section(S_SESSION_TABLE);
429 for (cptr = ContextList, i=0; cptr != NULL && i < nContexts; cptr = cptr->next, i++) {
430 memcpy(&nptr[i], cptr, sizeof (CitContext));
432 end_critical_section (S_SESSION_TABLE);
440 * Back-end function for starting a session
442 void begin_session(CitContext *con) {
444 * Initialize some variables specific to our context.
447 con->internal_pgm = 0;
448 con->download_fp = NULL;
449 con->upload_fp = NULL;
450 con->cached_msglist = NULL;
451 con->cached_num_msgs = 0;
452 con->FirstExpressMessage = NULL;
454 time(&con->lastidle);
455 strcpy(con->lastcmdname, " ");
456 strcpy(con->cs_clientname, "(unknown)");
457 strcpy(con->curr_user, NLI);
458 *con->cs_clientinfo = '\0';
459 safestrncpy(con->cs_host, CtdlGetConfigStr("c_fqdn"), sizeof con->cs_host);
460 safestrncpy(con->cs_addr, "", sizeof con->cs_addr);
461 con->cs_UDSclientUID = -1;
462 con->cs_host[sizeof con->cs_host - 1] = 0;
463 if (!CC->is_local_client) {
464 locate_host(con->cs_host, sizeof con->cs_host,
465 con->cs_addr, sizeof con->cs_addr,
472 #ifdef HAVE_STRUCT_UCRED
474 /* as http://www.wsinnovations.com/softeng/articles/uds.html told us... */
475 struct ucred credentials;
476 socklen_t ucred_length = sizeof(struct ucred);
478 /*fill in the user data structure */
479 if(getsockopt(con->client_socket, SOL_SOCKET, SO_PEERCRED, &credentials, &ucred_length)) {
480 syslog(LOG_ERR, "context: could obtain credentials from unix domain socket");
484 /* the process ID of the process on the other side of the socket */
485 /* credentials.pid; */
487 /* the effective UID of the process on the other side of the socket */
488 con->cs_UDSclientUID = credentials.uid;
490 /* the effective primary GID of the process on the other side of the socket */
491 /* credentials.gid; */
493 /* To get supplemental groups, we will have to look them up in our account
494 database, after a reverse lookup on the UID to get the account name.
495 We can take this opportunity to check to see if this is a legit account.
497 snprintf(con->cs_clientinfo, sizeof(con->cs_clientinfo),
498 "PID: "F_PID_T"; UID: "F_UID_T"; GID: "F_XPID_T" ",
509 if (((CtdlGetConfigInt("c_maxsessions") > 0)&&(num_sessions > CtdlGetConfigInt("c_maxsessions"))) || CtdlWantSingleUser()) {
513 syslog(LOG_INFO, "context: session (%s) started from %s (%s) uid=%d",
514 con->ServiceName, con->cs_host, con->cs_addr, con->cs_UDSclientUID
517 /* Run any session startup routines registered by loadable modules */
518 PerformSessionHooks(EVT_START);
523 * This function fills in a context and its user field correctly
524 * Then creates/loads that user
526 void CtdlFillSystemContext(CitContext *context, char *name) {
530 memset(context, 0, sizeof(CitContext));
531 context->internal_pgm = 1;
533 strcpy (sysname, "SYS_");
534 strcat (sysname, name);
535 len = strlen(sysname);
536 memcpy(context->curr_user, sysname, len + 1);
537 context->client_socket = (-1);
538 context->state = CON_SYS;
539 context->ServiceName = name;
541 /* internal_create_user has the side effect of loading the user regardless of whether they
542 * already existed or needed to be created
544 internal_create_user(sysname, &(context->user), -1) ;
546 /* Check to see if the system user needs upgrading */
547 if (context->user.usernum == 0) { /* old system user with number 0, upgrade it */
548 context->user.usernum = get_new_user_number();
549 syslog(LOG_INFO, "context: upgrading system user \"%s\" from user number 0 to user number %ld", context->user.fullname, context->user.usernum);
550 /* add user to the database */
551 CtdlPutUser(&(context->user));
552 cdb_store(CDB_USERSBYNUMBER, &(context->user.usernum), sizeof(long), context->user.fullname, strlen(context->user.fullname)+1);
558 * Cleanup any contexts that are left lying around
560 void context_cleanup(void) {
561 CitContext *ptr = NULL;
562 CitContext *rem = NULL;
565 * Clean up the contexts.
566 * There are no threads so no critical_section stuff is needed.
570 /* We need to update the ContextList because some modules may want to itterate it
571 * Question is should we NULL it before iterating here or should we just keep updating it
572 * as we remove items?
574 * Answer is to NULL it first to prevent modules from doing any actions on the list at all
578 /* Remove the session from the active list */
582 syslog(LOG_DEBUG, "context: context_cleanup() purging session %d", ptr->cs_pid);
591 * Purge all sessions which have the 'kill_me' flag set.
592 * This function has code to prevent it from running more than once every
593 * few seconds, because running it after every single unbind would waste a lot
594 * of CPU time and keep the context list locked too much. To force it to run
595 * anyway, set "force" to nonzero.
597 void dead_session_purge(int force) {
598 CitContext *ptr, *ptr2; /* general-purpose utility pointer */
599 CitContext *rem = NULL; /* list of sessions to be destroyed */
602 if ( (time(NULL) - last_purge) < 5 ) {
603 return; /* Too soon, go away */
608 if (try_critical_section(S_SESSION_TABLE))
616 if ( (ptr2->state == CON_IDLE) && (ptr2->kill_me) ) {
617 /* Remove the session from the active list */
619 ptr2->prev->next = ptr2->next;
622 ContextList = ptr2->next;
625 ptr2->next->prev = ptr2->prev;
629 /* And put it on our to-be-destroyed list */
634 end_critical_section(S_SESSION_TABLE);
636 /* Now that we no longer have the session list locked, we can take
637 * our time and destroy any sessions on the to-be-killed list, which
638 * is allocated privately on this thread's stack.
640 while (rem != NULL) {
641 syslog(LOG_DEBUG, "context: dead_session_purge() purging session %d, reason=%d", rem->cs_pid, rem->kill_me);
651 * masterCC is the context we use when not attached to a session. This
652 * function initializes it.
654 void InitializeMasterCC(void) {
655 memset(&masterCC, 0, sizeof(struct CitContext));
656 masterCC.internal_pgm = 1;
662 * Set the "async waiting" flag for a session, if applicable
664 void set_async_waiting(struct CitContext *ccptr) {
665 syslog(LOG_DEBUG, "context: setting async_waiting flag for session %d", ccptr->cs_pid);
666 if (ccptr->is_async) {
667 ccptr->async_waiting++;
668 if (ccptr->state == CON_IDLE) {
669 ccptr->state = CON_READY;
675 CTDL_MODULE_INIT(session)