1 // Citadel context management stuff.
2 // Here's where we (hopefully) have all the code that manipulates contexts.
4 // Copyright (c) 1987-2024 by the citadel.org team
6 // This program is open source software. Use, duplication, or disclosure
7 // is subject to the terms of the GNU General Public License, version 3.
9 #include "ctdl_module.h"
10 #include "serv_extensions.h"
11 #include "citserver.h"
13 #include "locate_host.h"
18 pthread_key_t MyConKey; // TSD key for MyContext()
20 CitContext *ContextList = NULL;
21 int num_sessions = 0; // Current number of sessions
24 // Flag for single user mode
25 static int want_single_user = 0;
27 // Try to go single user
29 int CtdlTrySingleUser(void) {
32 begin_critical_section(S_SINGLE_USER);
33 if (want_single_user) {
40 end_critical_section(S_SINGLE_USER);
45 void CtdlEndSingleUser(void) {
46 begin_critical_section(S_SINGLE_USER);
48 end_critical_section(S_SINGLE_USER);
52 int CtdlWantSingleUser(void) {
53 return want_single_user;
57 int CtdlIsSingleUser(void) {
58 if (want_single_user) {
59 // check for only one context here
60 if (num_sessions == 1)
67 // Locate a context by its session number and terminate it if the user is able.
68 // User can NOT terminate their current session.
69 // User CAN terminate any other session that has them logged in.
70 // Aide CAN terminate any session except the current one.
71 int CtdlTerminateOtherSession (int session_num) {
76 if (session_num == CC->cs_pid) return TERM_NOTALLOWED;
78 aide = ( (CC->user.axlevel >= AxAideU) || (CC->internal_pgm) ) ;
80 syslog(LOG_DEBUG, "context: locating session to kill");
81 begin_critical_section(S_SESSION_TABLE);
82 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
83 if (session_num == ccptr->cs_pid) {
85 if ((ccptr->user.usernum == CC->user.usernum) || aide) {
92 if (((ret & TERM_FOUND) != 0) && ((ret & TERM_ALLOWED) != 0)) {
93 if (ccptr->user.usernum == CC->user.usernum) {
94 ccptr->kill_me = KILLME_ADMIN_TERMINATE;
97 ccptr->kill_me = KILLME_IDLE;
99 end_critical_section(S_SESSION_TABLE);
102 end_critical_section(S_SESSION_TABLE);
109 // Check to see if the user who we just sent mail to is logged in. If yes,
110 // bump the 'new mail' counter for their session. That enables them to
111 // receive a new mail notification without having to hit the database.
112 void CtdlBumpNewMailCounter(long which_user) {
115 begin_critical_section(S_SESSION_TABLE);
117 for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
118 if (ptr->user.usernum == which_user) {
123 end_critical_section(S_SESSION_TABLE);
127 // Check to see if a user is currently logged in
128 // Take care with what you do as a result of this test.
129 // The user may not have been logged in when this function was called BUT
130 // because of threading the user might be logged in before you test the result.
131 int CtdlIsUserLoggedIn(char *user_name) {
135 begin_critical_section (S_SESSION_TABLE);
136 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
137 if (!strcasecmp(cptr->user.fullname, user_name)) {
142 end_critical_section(S_SESSION_TABLE);
147 // Check to see if a user is currently logged in.
148 // Basically same as CtdlIsUserLoggedIn() but uses the user number instead.
149 // Take care with what you do as a result of this test.
150 // The user may not have been logged in when this function was called BUT
151 // because of threading the user might be logged in before you test the result.
152 int CtdlIsUserLoggedInByNum (long usernum) {
156 begin_critical_section(S_SESSION_TABLE);
157 for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
158 if (cptr->user.usernum == usernum) {
162 end_critical_section(S_SESSION_TABLE);
167 // Return a pointer to the CitContext structure bound to the thread which
168 // called this function. If there's no such binding (for example, if it's
169 // called by the housekeeper thread) then a generic 'master' CC is returned.
171 // This function is used *VERY* frequently and must be kept small.
172 CitContext *MyContext(void) {
173 register CitContext *c;
174 return ((c = (CitContext *) pthread_getspecific(MyConKey), c == NULL) ? &masterCC : c);
178 // Terminate idle sessions. This function pounds through the session table
179 // comparing the current time to each session's time-of-last-command. If an
180 // idle session is found it is terminated, then the search restarts at the
181 // beginning because the pointer to our place in the list becomes invalid.
182 void terminate_idle_sessions(void) {
188 begin_critical_section(S_SESSION_TABLE);
189 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
192 && (CtdlGetConfigLong("c_sleeping") > 0)
193 && (now - (ccptr->lastcmd) > CtdlGetConfigLong("c_sleeping"))
195 ccptr->kill_me = KILLME_IDLE;
199 end_critical_section(S_SESSION_TABLE);
201 syslog(LOG_INFO, "context: scheduled %d idle sessions for termination", killed);
206 // During shutdown, close the sockets of any sessions still connected.
207 void terminate_all_sessions(void) {
211 begin_critical_section(S_SESSION_TABLE);
212 for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
213 if (ccptr->client_socket != -1) {
214 syslog(LOG_INFO, "context: terminate_all_sessions() is murdering %s CC[%d]", ccptr->curr_user, ccptr->cs_pid);
215 close(ccptr->client_socket);
216 ccptr->client_socket = -1;
220 end_critical_section(S_SESSION_TABLE);
222 syslog(LOG_INFO, "context: flushed %d stuck sessions", killed);
227 // Terminate a session.
228 void RemoveContext(CitContext *con) {
231 syslog(LOG_ERR, "context: RemoveContext() called with NULL, this should not happen");
234 c = con->ServiceName;
238 syslog(LOG_DEBUG, "context: RemoveContext(%s) session %d", c, con->cs_pid);
240 // Run any cleanup routines registered by loadable modules.
241 // Note: We have to "become_session()" because the cleanup functions might make references to "CC" assuming it's the right one.
244 PerformSessionHooks(EVT_STOP); // hooks may free some data structures, close SSL, etc.
245 client_close(); // If the client is still connected, disconnect them immediately.
246 become_session(NULL);
247 syslog(LOG_INFO, "context: session %d (%s) ended.", con->cs_pid, c);
249 // If using AUTHMODE_LDAP, free the DN
254 FreeStrBuf(&con->StatusMessage);
255 FreeStrBuf(&con->MigrateBuf);
256 FreeStrBuf(&con->RecvBuf.Buf);
257 if (con->cached_msglist) {
258 free(con->cached_msglist);
261 syslog(LOG_DEBUG, "context: done with RemoveContext()");
265 // Initialize a new context and place it in the list. The session number
266 // used to be the PID (which is why it's called cs_pid), but that was when we
267 // had one process per session. Now we just assign them sequentially, starting
268 // at 1 (don't change it to 0 because masterCC uses 0).
269 CitContext *CreateNewContext(void) {
272 me = (CitContext *) malloc(sizeof(CitContext));
274 syslog(LOG_ERR, "citserver: malloc() failed: %m");
277 memset(me, 0, sizeof(CitContext));
279 // Give the context a name. Hopefully makes it easier to track
280 strcpy (me->user.fullname, "SYS_notauth");
282 me->state = CON_EXECUTING; // Create new context already in CON_EXECUTING so another thread doesn't grab it.
283 me->MigrateBuf = NewStrBuf(); // Generate a unique session number
284 me->RecvBuf.Buf = NewStrBuf();
285 me->lastcmd = time(NULL); // set lastcmd to now to prevent idle timer infanticide
287 begin_critical_section(S_SESSION_TABLE);
288 me->cs_pid = ++next_pid;
290 me->next = ContextList;
292 if (me->next != NULL) {
296 end_critical_section(S_SESSION_TABLE);
301 // Initialize a new context and place it in the list. The session number
302 // used to be the PID (which is why it's called cs_pid), but that was when we
303 // had one process per session. Now we just assign them sequentially, starting
304 // at 1 (don't change it to 0 because masterCC uses 0).
305 CitContext *CloneContext(CitContext *CloneMe) {
308 me = (CitContext *) malloc(sizeof(CitContext));
310 syslog(LOG_ERR, "citserver: malloc() failed: %m");
313 memcpy(me, CloneMe, sizeof(CitContext));
315 memset(&me->RecvBuf, 0, sizeof(IOBuffer));
316 memset(&me->SendBuf, 0, sizeof(IOBuffer));
317 memset(&me->SBuf, 0, sizeof(IOBuffer));
318 me->MigrateBuf = NULL;
319 me->sMigrateBuf = NULL;
320 me->redirect_buffer = NULL;
325 me->download_fp = NULL;
326 me->upload_fp = NULL;
329 me->session_specific_data = NULL;
333 me->cached_msglist = NULL;
334 me->download_fp = NULL;
335 me->upload_fp = NULL;
336 me->client_socket = 0;
338 me->MigrateBuf = NewStrBuf();
339 me->RecvBuf.Buf = NewStrBuf();
341 begin_critical_section(S_SESSION_TABLE);
343 me->cs_pid = ++next_pid;
345 me->next = ContextList;
346 me->lastcmd = time(NULL); // set lastcmd to now to prevent idle timer infanticide
348 if (me->next != NULL) {
353 end_critical_section(S_SESSION_TABLE);
358 // Return an array containing a copy of the context list.
359 // This allows worker threads to perform "for each context" operations without
360 // having to lock and traverse the live list.
361 CitContext *CtdlGetContextArray(int *count) {
363 CitContext *nptr, *cptr;
365 nContexts = num_sessions;
366 nptr = malloc(sizeof(CitContext) * nContexts);
371 begin_critical_section(S_SESSION_TABLE);
372 for (cptr = ContextList, i=0; cptr != NULL && i < nContexts; cptr = cptr->next, i++) {
373 memcpy(&nptr[i], cptr, sizeof (CitContext));
375 end_critical_section (S_SESSION_TABLE);
382 // Back-end function for starting a session
383 void begin_session(CitContext *con) {
385 // Initialize some variables specific to our context.
387 con->internal_pgm = 0;
388 con->download_fp = NULL;
389 con->upload_fp = NULL;
390 con->cached_msglist = NULL;
391 con->cached_num_msgs = 0;
392 con->FirstExpressMessage = NULL;
394 time(&con->lastidle);
395 strcpy(con->lastcmdname, " ");
396 strcpy(con->cs_clientname, "(unknown)");
397 strcpy(con->curr_user, NLI);
398 *con->cs_clientinfo = '\0';
399 safestrncpy(con->cs_host, CtdlGetConfigStr("c_fqdn"), sizeof con->cs_host);
400 safestrncpy(con->cs_addr, "", sizeof con->cs_addr);
401 con->cs_UDSclientUID = -1;
402 con->cs_host[sizeof con->cs_host - 1] = 0;
403 if (!CC->is_local_client) {
404 locate_host(con->cs_host, sizeof con->cs_host,
405 con->cs_addr, sizeof con->cs_addr,
416 if (((CtdlGetConfigInt("c_maxsessions") > 0)&&(num_sessions > CtdlGetConfigInt("c_maxsessions"))) || CtdlWantSingleUser()) {
420 syslog(LOG_INFO, "context: session (%s) started from %s (%s) uid=%d",
421 con->ServiceName, con->cs_host, con->cs_addr, con->cs_UDSclientUID
424 // Run any session startup routines registered by loadable modules
425 PerformSessionHooks(EVT_START);
429 // This function fills in a context and its user field correctly
430 // Then creates/loads that user
431 void CtdlFillSystemContext(CitContext *context, char *name) {
435 memset(context, 0, sizeof(CitContext));
436 context->internal_pgm = 1;
438 strcpy (sysname, "SYS_");
439 strcat (sysname, name);
440 len = strlen(sysname);
441 memcpy(context->curr_user, sysname, len + 1);
442 context->client_socket = (-1);
443 context->state = CON_SYS;
444 context->ServiceName = name;
446 // internal_create_user has the side effect of loading the user regardless of whether they
447 // already existed or needed to be created
448 internal_create_user(sysname, &(context->user), -1) ;
450 // Check to see if the system user needs upgrading
451 if (context->user.usernum == 0) { // old system user with number 0, upgrade it
452 context->user.usernum = get_new_user_number();
453 syslog(LOG_INFO, "context: upgrading system user \"%s\" from user number 0 to user number %ld", context->user.fullname, context->user.usernum);
454 // add user to the database
455 CtdlPutUser(&(context->user));
456 cdb_store(CDB_USERSBYNUMBER, &(context->user.usernum), sizeof(long), context->user.fullname, strlen(context->user.fullname)+1);
461 // Cleanup any contexts that are left lying around
462 void context_cleanup(void) {
463 CitContext *ptr = NULL;
464 CitContext *rem = NULL;
466 // Clean up the contexts.
467 // There are no threads so no critical_section stuff is needed.
470 // We need to update the ContextList because some modules may want to iterate it
471 // Question is should we NULL it before iterating here or should we just keep updating it as we remove items?
472 // Answer is to NULL it first to prevent modules from doing any actions on the list at all.
475 // Remove the session from the active list
479 syslog(LOG_DEBUG, "context: context_cleanup() purging session %d", ptr->cs_pid);
487 // Purge all sessions which have the 'kill_me' flag set.
488 // This function has code to prevent it from running more than once every
489 // few seconds, because running it after every single unbind would waste a lot
490 // of CPU time and keep the context list locked too much. To force it to run
491 // anyway, set "force" to nonzero.
492 void dead_session_purge(int force) {
493 CitContext *ptr, *ptr2; // general-purpose utility pointer
494 CitContext *rem = NULL; // list of sessions to be destroyed
495 static time_t last_purge = 0; // Last dead session purge
498 if ( (time(NULL) - last_purge) < 5 ) {
499 return; // Too soon, go away
504 begin_critical_section(S_SESSION_TABLE);
510 if ( (ptr2->state == CON_IDLE) && (ptr2->kill_me) ) {
511 // Remove the session from the active list
513 ptr2->prev->next = ptr2->next;
516 ContextList = ptr2->next;
519 ptr2->next->prev = ptr2->prev;
523 // And put it on our to-be-destroyed list
527 //else if (ptr2->kill_me) {
528 // 2023: this was a source of segfaults but I think we fixed it
529 //syslog(LOG_DEBUG, "context: session %d is timed out but non-idle", ptr->cs_pid);
532 end_critical_section(S_SESSION_TABLE);
534 // Now that we no longer have the session list locked, we can take
535 // our time and destroy any sessions on the to-be-killed list, which
536 // is allocated privately on this thread's stack.
537 while (rem != NULL) {
538 syslog(LOG_DEBUG, "context: dead_session_purge() purging session %d, reason=%d", rem->cs_pid, rem->kill_me);
547 // masterCC is the context we use when not attached to a session. This function initializes it.
548 void InitializeMasterCC(void) {
549 memset(&masterCC, 0, sizeof(struct CitContext));
550 masterCC.internal_pgm = 1;
555 // Set the "async waiting" flag for a session, if applicable
556 void set_async_waiting(struct CitContext *ccptr) {
557 syslog(LOG_DEBUG, "context: setting async_waiting flag for session %d", ccptr->cs_pid);
558 if (ccptr->is_async) {
559 ccptr->async_waiting++;
560 if (ccptr->state == CON_IDLE) {
561 ccptr->state = CON_READY;
567 CTDL_MODULE_INIT(session) {