+/*
+ * $Id: sysdep.c 7989 2009-10-31 15:29:37Z davew $
+ *
+ * Citadel context management stuff.
+ * See COPYING for copyright information.
+ *
+ * Here's where we (hopefully) have all the code that manipulates contexts.
+ *
+ */
+
+#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>
+
+#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"
+
+
+
+citthread_key_t MyConKey; /* TSD key for MyContext() */
+
+
+struct CitContext masterCC;
+struct CitContext *ContextList = NULL;
+// struct CitContext* next_session = 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;
+}
+
+
+/*
+ * 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.
+ */
+struct CitContext *MyContext(void) {
+
+ register struct CitContext *c;
+
+ return ((c = (struct CitContext *) citthread_getspecific(MyConKey),
+ c == NULL) ? &masterCC : c
+ );
+}
+
+
+
+
+/*
+ * Terminate a session.
+ */
+void RemoveContext (struct CitContext *con)
+{
+ if (con==NULL) {
+ CtdlLogPrintf(CTDL_ERR,
+ "WARNING: RemoveContext() called with NULL!\n");
+ return;
+ }
+ CtdlLogPrintf(CTDL_DEBUG, "RemoveContext() session %d\n", con->cs_pid);
+
+ /* 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);
+ logout();
+ PerformSessionHooks(EVT_STOP);
+ become_session(NULL);
+
+ CtdlLogPrintf(CTDL_NOTICE, "[%3d] Session ended.\n", con->cs_pid);
+
+ /* If the client is still connected, blow 'em away. */
+ CtdlLogPrintf(CTDL_DEBUG, "Closing socket %d\n", 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;
+ }
+
+ CtdlLogPrintf(CTDL_DEBUG, "Done with RemoveContext()\n");
+}
+
+
+
+
+
+/*
+ * 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).
+ */
+struct CitContext *CreateNewContext(void) {
+ struct CitContext *me;
+ static int next_pid = 0;
+
+ me = (struct CitContext *) malloc(sizeof(struct CitContext));
+ if (me == NULL) {
+ CtdlLogPrintf(CTDL_ALERT, "citserver: can't allocate memory!!\n");
+ return NULL;
+ }
+
+ memset(me, 0, sizeof(struct CitContext));
+
+ /* Give the contaxt 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.
+ */
+ 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);
+}
+
+
+struct CitContext *CtdlGetContextArray(int *count)
+{
+ int nContexts, i;
+ struct CitContext *nptr, *cptr;
+
+ nContexts = num_sessions;
+ nptr = malloc(sizeof(struct CitContext) * nContexts);
+ if (!nptr)
+ 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 (struct 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(struct CitContext *context, char *name)
+{
+ char sysname[USERNAME_SIZE];
+
+ memset(context, 0, sizeof(struct CitContext));
+ context->internal_pgm = 1;
+ context->cs_pid = 0;
+ strcpy (sysname, "SYS_");
+ strcat (sysname, 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, &(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();
+ CtdlLogPrintf(CTDL_DEBUG, "Upgrading system user \"%s\" from user number 0 to user number %d\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)
+{
+ struct CitContext *ptr = NULL;
+ struct 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;
+
+ CtdlLogPrintf(CTDL_DEBUG, "Purging session %d\n", ptr->cs_pid);
+ RemoveContext(ptr);
+ free (ptr);
+ ptr = rem;
+ }
+}
+
+
+
+/*
+ * Terminate another session.
+ * (This could justifiably be moved out of sysdep.c because it
+ * no longer does anything that is system-dependent.)
+ */
+void kill_session(int session_to_kill) {
+ struct CitContext *ptr;
+
+ begin_critical_section(S_SESSION_TABLE);
+ for (ptr = ContextList; ptr != NULL; ptr = ptr->next) {
+ if (ptr->cs_pid == session_to_kill) {
+ ptr->kill_me = 1;
+ }
+ }
+ end_critical_section(S_SESSION_TABLE);
+}
+
+/*
+ * 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) {
+ struct CitContext *ptr, *ptr2; /* general-purpose utility pointer */
+ struct 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) {
+ CtdlLogPrintf(CTDL_DEBUG, "Purging session %d\n", rem->cs_pid);
+ 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;
+}
+
+
+
+
+/*
+ * Bind a thread to a context. (It's inline merely to speed things up.)
+ */
+INLINE void become_session(struct CitContext *which_con) {
+ citthread_setspecific(MyConKey, (void *)which_con );
+}
+
+
+