/*
* Citadel context management stuff.
* Here's where we (hopefully) have all the code that manipulates contexts.
*
* Copyright (c) 1987-2011 by the citadel.org team
*
* This program is open source software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "sysdep.h"
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <ctype.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <syslog.h>
#include <sys/syslog.h>
/*
#include <sys/syscall.h>
*/
#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
# include <sys/time.h>
# else
# include <time.h>
# endif
#endif
#include <limits.h>
#include <sys/resource.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/un.h>
#include <string.h>
#include <pwd.h>
#include <errno.h>
#include <stdarg.h>
#include <grp.h>
#include <libcitadel.h>
#include "citadel.h"
#include "server.h"
#include "sysdep_decls.h"
#include "citserver.h"
#include "support.h"
#include "config.h"
#include "database.h"
#include "housekeeping.h"
#include "modules/crypto/serv_crypto.h" /* Needed for init_ssl, client_write_ssl, client_read_ssl, destruct_ssl */
#include "ecrash.h"
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#ifndef HAVE_SNPRINTF
#include "snprintf.h"
#endif
#include "ctdl_module.h"
#include "threads.h"
#include "user_ops.h"
#include "control.h"
int DebugSession = 0;
pthread_key_t MyConKey; /* TSD key for MyContext() */
CitContext masterCC;
CitContext *ContextList = NULL;
time_t last_purge = 0; /* Last dead session purge */
int num_sessions = 0; /* Current number of sessions */
/* Flag for single user mode */
static int want_single_user = 0;
/* Try to go single user */
int CtdlTrySingleUser(void)
{
int can_do = 0;
begin_critical_section(S_SINGLE_USER);
if (want_single_user)
can_do = 0;
else
{
can_do = 1;
want_single_user = 1;
}
end_critical_section(S_SINGLE_USER);
return can_do;
}
void CtdlEndSingleUser(void)
{
begin_critical_section(S_SINGLE_USER);
want_single_user = 0;
end_critical_section(S_SINGLE_USER);
}
int CtdlWantSingleUser(void)
{
return want_single_user;
}
int CtdlIsSingleUser(void)
{
if (want_single_user)
{
/* check for only one context here */
if (num_sessions == 1)
return TRUE;
}
return FALSE;
}
/*
* Locate a context by its session number and terminate it if the user is able.
* User can NOT terminate their current session.
* User CAN terminate any other session that has them logged in.
* Aide CAN terminate any session except the current one.
*/
int CtdlTerminateOtherSession (int session_num)
{
int ret = 0;
CitContext *ccptr;
if (session_num == CC->cs_pid) {
return TERM_NOTALLOWED;
}
CONM_syslog(LOG_DEBUG, "Locating session to kill\n");
begin_critical_section(S_SESSION_TABLE);
for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
if (session_num == ccptr->cs_pid) {
ret |= TERM_FOUND;
if ((ccptr->user.usernum == CC->user.usernum)
|| (CC->user.axlevel >= AxAideU)) {
ret |= TERM_ALLOWED;
ccptr->kill_me = KILLME_ADMIN_TERMINATE;
}
}
}
end_critical_section(S_SESSION_TABLE);
return ret;
}
/*
* Check to see if the user who we just sent mail to is logged in. If yes,
* bump the 'new mail' counter for their session. That enables them to
* receive a new mail notification without having to hit the database.
*/
void BumpNewMailCounter(long which_user)
{
CtdlBumpNewMailCounter(which_user);
}
void CtdlBumpNewMailCounter(long which_user)
{
CitContext *ptr;
begin_critical_section(S_SESSION_TABLE);
for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
if (ptr->user.usernum == which_user) {
ptr->newmail += 1;
}
}
end_critical_section(S_SESSION_TABLE);
}
/*
* Check to see if a user is currently logged in
* Take care with what you do as a result of this test.
* The user may not have been logged in when this function was called BUT
* because of threading the user might be logged in before you test the result.
*/
int CtdlIsUserLoggedIn (char *user_name)
{
CitContext *cptr;
int ret = 0;
begin_critical_section (S_SESSION_TABLE);
for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
if (!strcasecmp(cptr->user.fullname, user_name)) {
ret = 1;
break;
}
}
end_critical_section(S_SESSION_TABLE);
return ret;
}
/*
* Check to see if a user is currently logged in.
* Basically same as CtdlIsUserLoggedIn() but uses the user number instead.
* Take care with what you do as a result of this test.
* The user may not have been logged in when this function was called BUT
* because of threading the user might be logged in before you test the result.
*/
int CtdlIsUserLoggedInByNum (long usernum)
{
CitContext *cptr;
int ret = 0;
begin_critical_section(S_SESSION_TABLE);
for (cptr = ContextList; cptr != NULL; cptr = cptr->next) {
if (cptr->user.usernum == usernum) {
ret = 1;
}
}
end_critical_section(S_SESSION_TABLE);
return ret;
}
/*
* Return a pointer to the CitContext structure bound to the thread which
* called this function. If there's no such binding (for example, if it's
* called by the housekeeper thread) then a generic 'master' CC is returned.
*
* This function is used *VERY* frequently and must be kept small.
*/
CitContext *MyContext(void) {
register CitContext *c;
return ((c = (CitContext *) pthread_getspecific(MyConKey), c == NULL) ? &masterCC : c);
}
/*
* Terminate idle sessions. This function pounds through the session table
* comparing the current time to each session's time-of-last-command. If an
* idle session is found it is terminated, then the search restarts at the
* beginning because the pointer to our place in the list becomes invalid.
*/
void terminate_idle_sessions(void)
{
CitContext *ccptr;
time_t now;
int killed = 0;
int longrunners = 0;
now = time(NULL);
begin_critical_section(S_SESSION_TABLE);
for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
if (
(ccptr != CC)
&& (config.c_sleeping > 0)
&& (now - (ccptr->lastcmd) > config.c_sleeping)
) {
if (!ccptr->dont_term) {
ccptr->kill_me = KILLME_IDLE;
++killed;
}
else {
++longrunners;
}
}
}
end_critical_section(S_SESSION_TABLE);
if (killed > 0)
CON_syslog(LOG_INFO, "Scheduled %d idle sessions for termination\n", killed);
if (longrunners > 0)
CON_syslog(LOG_INFO, "Didn't terminate %d protected idle sessions", longrunners);
}
/*
* During shutdown, close the sockets of any sessions still connected.
*/
void terminate_all_sessions(void)
{
CitContext *ccptr;
int killed = 0;
begin_critical_section(S_SESSION_TABLE);
for (ccptr = ContextList; ccptr != NULL; ccptr = ccptr->next) {
if (ccptr->client_socket != -1)
{
CON_syslog(LOG_INFO, "terminate_all_sessions() is murdering %s", ccptr->curr_user);
close(ccptr->client_socket);
ccptr->client_socket = -1;
killed++;
}
}
end_critical_section(S_SESSION_TABLE);
if (killed > 0) {
CON_syslog(LOG_INFO, "Flushed %d stuck sessions\n", killed);
}
}
/*
* Terminate a session.
*/
void RemoveContext (CitContext *con)
{
const char *c;
if (con == NULL) {
CONM_syslog(LOG_ERR, "WARNING: RemoveContext() called with NULL!");
return;
}
c = con->ServiceName;
if (c == NULL) {
c = "WTF?";
}
CON_syslog(LOG_DEBUG, "RemoveContext(%s) session %d", c, con->cs_pid);
/// cit_backtrace();
/* Run any cleanup routines registered by loadable modules.
* Note: We have to "become_session()" because the cleanup functions
* might make references to "CC" assuming it's the right one.
*/
become_session(con);
CtdlUserLogout();
PerformSessionHooks(EVT_STOP);
client_close(); /* If the client is still connected, blow 'em away. */
become_session(NULL);
CON_syslog(LOG_NOTICE, "[%3d]SRV[%s] Session ended.", con->cs_pid, c);
/*
* If the client is still connected, blow 'em away.
* if the socket is 0 or -1, its already gone or was never there.
*/
if (con->client_socket > 0)
{
CON_syslog(LOG_NOTICE, "Closing socket %d", con->client_socket);
close(con->client_socket);
}
/* If using AUTHMODE_LDAP, free the DN */
if (con->ldap_dn) {
free(con->ldap_dn);
con->ldap_dn = NULL;
}
FreeStrBuf(&con->StatusMessage);
FreeStrBuf(&con->MigrateBuf);
FreeStrBuf(&con->RecvBuf.Buf);
if (con->cached_msglist) {
free(con->cached_msglist);
}
CONM_syslog(LOG_DEBUG, "Done with RemoveContext()");
}
/*
* Initialize a new context and place it in the list. The session number
* used to be the PID (which is why it's called cs_pid), but that was when we
* had one process per session. Now we just assign them sequentially, starting
* at 1 (don't change it to 0 because masterCC uses 0).
*/
CitContext *CreateNewContext(void) {
CitContext *me;
static int next_pid = 0;
me = (CitContext *) malloc(sizeof(CitContext));
if (me == NULL) {
CONM_syslog(LOG_ALERT, "citserver: can't allocate memory!!\n");
return NULL;
}
memset(me, 0, sizeof(CitContext));
/* Give the context a name. Hopefully makes it easier to track */
strcpy (me->user.fullname, "SYS_notauth");
/* The new context will be created already in the CON_EXECUTING state
* in order to prevent another thread from grabbing it while it's
* being set up.
*/
me->state = CON_EXECUTING;
/*
* Generate a unique session number and insert this context into
* the list.
*/
me->MigrateBuf = NewStrBuf();
me->RecvBuf.Buf = NewStrBuf();
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. */
begin_critical_section(S_SESSION_TABLE);
me->cs_pid = ++next_pid;
me->prev = NULL;
me->next = ContextList;
ContextList = me;
if (me->next != NULL) {
me->next->prev = me;
}
++num_sessions;
end_critical_section(S_SESSION_TABLE);
return (me);
}
/*
* Initialize a new context and place it in the list. The session number
* used to be the PID (which is why it's called cs_pid), but that was when we
* had one process per session. Now we just assign them sequentially, starting
* at 1 (don't change it to 0 because masterCC uses 0).
*/
CitContext *CloneContext(CitContext *CloneMe) {
CitContext *me;
static int next_pid = 0;
me = (CitContext *) malloc(sizeof(CitContext));
if (me == NULL) {
CONM_syslog(LOG_ALERT, "citserver: can't allocate memory!!\n");
return NULL;
}
memcpy(me, CloneMe, sizeof(CitContext));
memset(&me->RecvBuf, 0, sizeof(IOBuffer));
memset(&me->SendBuf, 0, sizeof(IOBuffer));
memset(&me->SBuf, 0, sizeof(IOBuffer));
me->MigrateBuf = NULL;
me->sMigrateBuf = NULL;
me->redirect_buffer = NULL;
#ifdef HAVE_OPENSSL
me->ssl = NULL;
#endif
me->download_fp = NULL;
me->upload_fp = NULL;
/// TODO: what about the room/user?
me->ma = NULL;
me->openid_data = NULL;
me->ldap_dn = NULL;
me->session_specific_data = NULL;
me->download_fp = NULL;
me->upload_fp = NULL;
me->client_socket = 0;
me->MigrateBuf = NewStrBuf();
me->RecvBuf.Buf = NewStrBuf();
begin_critical_section(S_SESSION_TABLE);
{
me->cs_pid = ++next_pid;
me->prev = NULL;
me->next = ContextList;
me->lastcmd = time(NULL); /* set lastcmd to now to prevent idle timer infanticide */
ContextList = me;
if (me->next != NULL) {
me->next->prev = me;
}
++num_sessions;
}
end_critical_section(S_SESSION_TABLE);
return (me);
}
/*
* Return an array containing a copy of the context list.
* This allows worker threads to perform "for each context" operations without
* having to lock and traverse the live list.
*/
CitContext *CtdlGetContextArray(int *count)
{
int nContexts, i;
CitContext *nptr, *cptr;
nContexts = num_sessions;
nptr = malloc(sizeof(CitContext) * nContexts);
if (!nptr) {
*count = 0;
return NULL;
}
begin_critical_section(S_SESSION_TABLE);
for (cptr = ContextList, i=0; cptr != NULL && i < nContexts; cptr = cptr->next, i++) {
memcpy(&nptr[i], cptr, sizeof (CitContext));
}
end_critical_section (S_SESSION_TABLE);
*count = i;
return nptr;
}
/*
* This function fills in a context and its user field correctly
* Then creates/loads that user
*/
void CtdlFillSystemContext(CitContext *context, char *name)
{
char sysname[SIZ];
long len;
memset(context, 0, sizeof(CitContext));
context->internal_pgm = 1;
context->cs_pid = 0;
strcpy (sysname, "SYS_");
strcat (sysname, name);
len = cutuserkey(sysname);
memcpy(context->curr_user, sysname, len + 1);
context->client_socket = (-1);
context->state = CON_SYS;
context->ServiceName = name;
/* internal_create_user has the side effect of loading the user regardless of wether they
* already existed or needed to be created
*/
internal_create_user (sysname, len, &(context->user), -1) ;
/* Check to see if the system user needs upgrading */
if (context->user.usernum == 0)
{ /* old system user with number 0, upgrade it */
context->user.usernum = get_new_user_number();
CON_syslog(LOG_INFO, "Upgrading system user \"%s\" from user number 0 to user number %ld\n", context->user.fullname, context->user.usernum);
/* add user to the database */
CtdlPutUser(&(context->user));
cdb_store(CDB_USERSBYNUMBER, &(context->user.usernum), sizeof(long), context->user.fullname, strlen(context->user.fullname)+1);
}
}
/*
* Cleanup any contexts that are left lying around
*/
void context_cleanup(void)
{
CitContext *ptr = NULL;
CitContext *rem = NULL;
/*
* Clean up the contexts.
* There are no threads so no critical_section stuff is needed.
*/
ptr = ContextList;
/* We need to update the ContextList because some modules may want to itterate it
* Question is should we NULL it before iterating here or should we just keep updating it
* as we remove items?
*
* Answer is to NULL it first to prevent modules from doing any actions on the list at all
*/
ContextList=NULL;
while (ptr != NULL){
/* Remove the session from the active list */
rem = ptr->next;
--num_sessions;
CON_syslog(LOG_DEBUG, "context_cleanup(): purging session %d\n", ptr->cs_pid);
RemoveContext(ptr);
free (ptr);
ptr = rem;
}
}
/*
* Purge all sessions which have the 'kill_me' flag set.
* This function has code to prevent it from running more than once every
* few seconds, because running it after every single unbind would waste a lot
* of CPU time and keep the context list locked too much. To force it to run
* anyway, set "force" to nonzero.
*/
void dead_session_purge(int force) {
CitContext *ptr, *ptr2; /* general-purpose utility pointer */
CitContext *rem = NULL; /* list of sessions to be destroyed */
if (force == 0) {
if ( (time(NULL) - last_purge) < 5 ) {
return; /* Too soon, go away */
}
}
time(&last_purge);
if (try_critical_section(S_SESSION_TABLE))
return;
ptr = ContextList;
while (ptr) {
ptr2 = ptr;
ptr = ptr->next;
if ( (ptr2->state == CON_IDLE) && (ptr2->kill_me) ) {
/* Remove the session from the active list */
if (ptr2->prev) {
ptr2->prev->next = ptr2->next;
}
else {
ContextList = ptr2->next;
}
if (ptr2->next) {
ptr2->next->prev = ptr2->prev;
}
--num_sessions;
/* And put it on our to-be-destroyed list */
ptr2->next = rem;
rem = ptr2;
}
}
end_critical_section(S_SESSION_TABLE);
/* Now that we no longer have the session list locked, we can take
* our time and destroy any sessions on the to-be-killed list, which
* is allocated privately on this thread's stack.
*/
while (rem != NULL) {
CON_syslog(LOG_DEBUG, "dead_session_purge(): purging session %d, reason=%d\n", rem->cs_pid, rem->kill_me);
RemoveContext(rem);
ptr = rem;
rem = rem->next;
free(ptr);
}
}
/*
* masterCC is the context we use when not attached to a session. This
* function initializes it.
*/
void InitializeMasterCC(void) {
memset(&masterCC, 0, sizeof(struct CitContext));
masterCC.internal_pgm = 1;
masterCC.cs_pid = 0;
}
/*
* Set the "async waiting" flag for a session, if applicable
*/
void set_async_waiting(struct CitContext *ccptr)
{
CON_syslog(LOG_DEBUG, "Setting async_waiting flag for session %d\n", ccptr->cs_pid);
if (ccptr->is_async) {
ccptr->async_waiting++;
if (ccptr->state == CON_IDLE) {
ccptr->state = CON_READY;
}
}
}
void DebugSessionEnable(const int n)
{
DebugSession = n;
}
CTDL_MODULE_INIT(session)
{
if (!threading) {
CtdlRegisterDebugFlagHook(HKEY("session"), DebugSessionEnable, &DebugSession);
}
return "session";
}