--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libfreeDiameter/sessions.c	Wed Sep 02 18:22:00 2009 +0900
@@ -0,0 +1,671 @@
+/*********************************************************************************************************
+* Software License Agreement (BSD License)                                                               *
+* Author: Sebastien Decugis <sdecugis@nict.go.jp>							 *
+*													 *
+* Copyright (c) 2009, WIDE Project and NICT								 *
+* All rights reserved.											 *
+* 													 *
+* Redistribution and use of this software in source and binary forms, with or without modification, are  *
+* permitted provided that the following conditions are met:						 *
+* 													 *
+* * Redistributions of source code must retain the above 						 *
+*   copyright notice, this list of conditions and the 							 *
+*   following disclaimer.										 *
+*    													 *
+* * Redistributions in binary form must reproduce the above 						 *
+*   copyright notice, this list of conditions and the 							 *
+*   following disclaimer in the documentation and/or other						 *
+*   materials provided with the distribution.								 *
+* 													 *
+* * Neither the name of the WIDE Project or NICT nor the 						 *
+*   names of its contributors may be used to endorse or 						 *
+*   promote products derived from this software without 						 *
+*   specific prior written permission of WIDE Project and 						 *
+*   NICT.												 *
+* 													 *
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED *
+* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A *
+* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR *
+* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 	 *
+* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 	 *
+* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR *
+* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF   *
+* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.								 *
+*********************************************************************************************************/
+
+/* Sessions module.
+ * 
+ * Basic functionalities to help implementing User sessions state machines from RFC3588.
+ */
+
+#include "libfD.h"
+
+/*********************** Parameters **********************/
+
+/* Size of the hash table containing the session objects (pow of 2. ex: 6 => 2^6 = 64). must be between 0 and 31. */
+#ifndef SESS_HASH_SIZE
+#define SESS_HASH_SIZE	6
+#endif /* SESS_HASH_SIZE */
+
+/* Default lifetime of a session, in seconds. (31 days = 2678400 seconds) */
+#ifndef SESS_DEFAULT_LIFETIME
+#define SESS_DEFAULT_LIFETIME	2678400
+#endif /* SESS_DEFAULT_LIFETIME */
+
+/********************** /Parameters **********************/
+
+/* Eyescatchers definitions */
+#define SH_EYEC 0x53554AD1
+#define SD_EYEC 0x5355D474
+#define SI_EYEC 0x53551D
+
+/* Macro to check an object is valid */
+#define VALIDATE_SH( _obj ) ( ((_obj) != NULL) && ( ((struct session_handler *)(_obj))->eyec == SH_EYEC) )
+#define VALIDATE_SI( _obj ) ( ((_obj) != NULL) && ( ((struct session         *)(_obj))->eyec == SI_EYEC) )
+
+
+/* Handlers registered by users of the session module */
+struct session_handler {
+	int		  eyec;	/* An eye catcher also used to ensure the object is valid, must be SH_EYEC */
+	int		  id;	/* A unique integer to identify this handler */
+	void 		(*cleanup)(char *, session_state *); /* The cleanup function to be called for cleaning a state */
+};
+
+static int 		hdl_id = 0;				/* A global counter to initialize the id field */
+static pthread_mutex_t	hdl_lock = PTHREAD_MUTEX_INITIALIZER;	/* lock to protect hdl_id; we could use atomic operations otherwise (less portable) */
+
+
+/* Data structures linked from the sessions, containing the applications states */
+struct state {
+	int			 eyec;	/* Must be SD_EYEC */
+	session_state		*state;	/* The state registered by the application, never NULL (or the whole object is deleted) */
+	struct fd_list		 chain;	/* Chaining in the list of session's states ordered by hdl->id */
+	union {
+		struct session_handler	*hdl;	/* The handler for which this state was registered */
+		char 			*sid;	/* For deleted state, the sid of the session it belong to */
+	};
+};
+
+/* Session object, one for each value of Session-Id AVP */
+struct session {
+	int 		eyec;	/* Eyecatcher, SI_EYEC */
+	
+	char *		sid;	/* The \0-terminated Session-Id */
+	uint32_t	hash;	/* computed hash of sid */
+	struct fd_list	chain_h;/* chaining in the hash table of sessions. */
+	
+	struct timespec	timeout;/* Timeout date for the session */
+	struct fd_list	expire;	/* List of expiring sessions, ordered by timeouts. */
+	
+	pthread_mutex_t stlock;	/* A lock to protect the list of states associated with this session */
+	struct fd_list	states;	/* Sentinel for the list of states of this session. */
+};
+
+/* Sessions hash table, to allow fast sid to session retrieval */
+static struct {
+	struct fd_list	sentinel;	/* sentinel element for this sublist */
+	pthread_mutex_t lock;		/* the mutex for this sublist */
+} sess_hash [ 1 << SESS_HASH_SIZE ] ;
+#define H_MASK( __hash ) ((__hash) & (( 1 << SESS_HASH_SIZE ) - 1))
+#define H_LIST( _hash ) (&(sess_hash[H_MASK(_hash)].sentinel))
+#define H_LOCK( _hash ) (&(sess_hash[H_MASK(_hash)].lock    ))
+
+/* The following are used to generate sid values that are eternaly unique */
+static uint32_t   	sid_h;	/* initialized to the current time in fd_sess_init */
+static uint32_t   	sid_l;	/* incremented each time a session id is created -- could use atomic operation probably */
+static pthread_mutex_t 	sid_lock = PTHREAD_MUTEX_INITIALIZER;
+
+/* Expiring sessions management */
+static struct fd_list	exp_sentinel;	/* list of sessions ordered by their timeout date */
+static pthread_mutex_t	exp_lock = PTHREAD_MUTEX_INITIALIZER;	/* lock protecting the list. */
+static pthread_cond_t	exp_cond = PTHREAD_COND_INITIALIZER;	/* condvar used by the expiry mecahinsm. */
+static pthread_t	exp_thr; 	/* The expiry thread that handles cleanup of expired sessions */
+
+/* Hierarchy of the locks, to avoid deadlocks:
+ *  hash lock > state lock > expiry lock
+ * i.e. state lock can be taken while holding the hash lock, but not while holding the expiry lock.
+ * As well, the hash lock cannot be taken while holding a state lock.
+ */
+
+/********************************************************************************************************/
+
+/* Initialize a session object. It is not linked now. sid must be already alloc'ed. */
+static struct session * new_session(char * sid, size_t sidlen)
+{
+	struct session * sess;
+	
+	TRACE_ENTRY("%p %d", sid, sidlen);
+	CHECK_PARAMS_DO( sid && sidlen, return NULL );
+	
+	CHECK_MALLOC_DO( sess = malloc(sizeof(struct session)), return NULL );
+	memset(sess, 0, sizeof(struct session));
+	
+	sess->eyec = SI_EYEC;
+	
+	sess->sid  = sid;
+	sess->hash = fd_hash(sid, sidlen);
+	fd_list_init(&sess->chain_h, sess);
+	
+	CHECK_SYS_DO( clock_gettime(CLOCK_REALTIME, &sess->timeout), return NULL );
+	sess->timeout.tv_sec += SESS_DEFAULT_LIFETIME;
+	fd_list_init(&sess->expire, sess);
+	
+	CHECK_POSIX_DO( pthread_mutex_init(&sess->stlock, NULL), return NULL );
+	fd_list_init(&sess->states, sess);
+	
+	return sess;
+}
+	
+
+
+
+/* The expiry thread */
+static void * exp_fct(void * arg)
+{
+	fd_log_threadname ( "Session/expire" );
+	TRACE_ENTRY( "" );
+	
+	CHECK_POSIX_DO( pthread_mutex_lock(&exp_lock),  goto error );
+	pthread_cleanup_push( fd_cleanup_mutex, &exp_lock );
+	
+	do {
+		struct timespec	now;
+		struct session * first;
+		
+		/* Check if there are expiring sessions available */
+		if (FD_IS_LIST_EMPTY(&exp_sentinel)) {
+			/* Just wait for a change or cancelation */
+			CHECK_POSIX_DO( pthread_cond_wait( &exp_cond, &exp_lock ), goto error );
+			/* Restart the loop on wakeup */
+			continue;
+		}
+		
+		/* Get the pointer to the session that expires first */
+		first = (struct session *)(exp_sentinel.next->o);
+		ASSERT( VALIDATE_SI(first) );
+		
+		/* Get the current time */
+		CHECK_SYS_DO(  clock_gettime(CLOCK_REALTIME, &now),  goto error  );
+
+		/* If first session is not expired, we just wait until it happens */
+		if ( TS_IS_INFERIOR( &now, &first->timeout ) ) {
+			
+			CHECK_POSIX_DO2(  pthread_cond_timedwait( &exp_cond, &exp_lock, &first->timeout ),  
+					ETIMEDOUT, /* ETIMEDOUT is a normal error, continue */,
+					/* on other error, */ goto error );
+	
+			/* on wakeup, loop */
+			continue;
+		}
+		
+		/* Now, the first session in the list is expired; destroy it */
+		CHECK_POSIX_DO( pthread_mutex_unlock(&exp_lock),  goto error );
+		CHECK_FCT_DO( fd_sess_destroy( &first ), goto error );
+		CHECK_POSIX_DO( pthread_mutex_lock(&exp_lock),  goto error );
+		
+	} while (1);
+	
+	pthread_cleanup_pop( 1 );
+error:
+	TRACE_DEBUG(INFO, "An error occurred in session module! Expiry thread is terminating...");
+	ASSERT(0);
+	return NULL;
+}
+	
+	
+
+/********************************************************************************************************/
+
+/* Initialize the session module */
+int fd_sess_init(void)
+{
+	int i;
+	
+	TRACE_ENTRY( "" );
+	
+	/* Initialize the global counters */
+	sid_h = (uint32_t) time(NULL);
+	sid_l = 0;
+	
+	/* Initialize the hash table */
+	for (i = 0; i < sizeof(sess_hash) / sizeof(sess_hash[0]); i++) {
+		fd_list_init( &sess_hash[i].sentinel, NULL );
+		CHECK_POSIX(  pthread_mutex_init(&sess_hash[i].lock, NULL)  );
+	}
+	
+	/* Initialize expiry management */
+	fd_list_init( &exp_sentinel, NULL );
+	CHECK_POSIX(  pthread_create(&exp_thr, NULL, exp_fct, NULL)  );
+	
+	return 0;
+}
+
+/* Create a new handler */
+int fd_sess_handler_create_int ( struct session_handler ** handler, void (*cleanup)(char * sid, session_state * state) )
+{
+	struct session_handler *new;
+	
+	TRACE_ENTRY("%p %p", handler, cleanup);
+	
+	CHECK_PARAMS( handler && cleanup );
+	
+	CHECK_MALLOC( new = malloc(sizeof(struct session_handler)) );
+	memset(new, 0, sizeof(struct session_handler));
+	
+	CHECK_POSIX( pthread_mutex_lock(&hdl_lock) );
+	new->id = ++hdl_id;
+	CHECK_POSIX( pthread_mutex_unlock(&hdl_lock) );
+	
+	new->eyec = SH_EYEC;
+	new->cleanup = cleanup;
+	
+	*handler = new;
+	return 0;
+}
+
+/* Destroy a handler, and all states attached to this handler. This operation is very slow but we don't care since it's rarely used. 
+ * Note that it's better to call this function after all sessions have been deleted... */
+int fd_sess_handler_destroy ( struct session_handler ** handler )
+{
+	struct session_handler * del;
+	struct fd_list deleted_states; /* Save the list of states to be cleaned up. We do it after finding them to avoid deadlocks. the "o" field becomes a copy of the sid. */
+	int i;
+	
+	TRACE_ENTRY("%p", handler);
+	CHECK_PARAMS( handler && VALIDATE_SH(*handler) );
+	
+	del = *handler;
+	*handler = NULL;
+	fd_list_init(&deleted_states, NULL);
+	
+	del->eyec = 0xdead; /* The handler is not valid anymore for any other operation */
+	
+	/* Now find all sessions with data registered for this handler, and move this data to the deleted_states list. */
+	for (i = 0; i < sizeof(sess_hash) / sizeof(sess_hash[0]); i++) {
+		struct fd_list * li_si;
+		CHECK_POSIX(  pthread_mutex_lock(&sess_hash[i].lock)  );
+		
+		for (li_si = sess_hash[i].sentinel.next; li_si != &sess_hash[i].sentinel; li_si = li_si->next) {
+			struct fd_list * li_st;
+			struct session * sess = (struct session *)(li_si->o);
+			CHECK_POSIX(  pthread_mutex_lock(&sess->stlock)  );
+			for (li_st = sess->states.next; li_st != &sess->states; li_st = li_st->next) {
+				struct state * st = (struct state *)(li_st->o);
+				char * sid_cpy;
+				/* The list is ordered */
+				if (st->hdl->id < del->id)
+					continue;
+				if (st->hdl->id > del->id)
+					break;
+				/* This state belongs to the handler we are deleting, move the item to the deleted_states list */
+				fd_list_unlink(&st->chain);
+				CHECK_MALLOC( st->sid = strdup(sess->sid) );
+				fd_list_insert_before(&deleted_states, &st->chain);
+			}
+			CHECK_POSIX(  pthread_mutex_unlock(&sess->stlock)  );
+		}
+		CHECK_POSIX(  pthread_mutex_unlock(&sess_hash[i].lock)  );
+	}
+	
+	/* Now, delete all states after calling their cleanup handler */
+	while (!FD_IS_LIST_EMPTY(&deleted_states)) {
+		struct state * st = (struct state *)(deleted_states.next->o);
+		TRACE_DEBUG(FULL, "Calling cleanup handler for session '%s' and data %p", st->sid, st->state);
+		(*del->cleanup)(st->sid, st->state);
+		free(st->sid);
+		fd_list_unlink(&st->chain);
+		free(st);
+	}
+	
+	return 0;
+}
+
+
+
+/* Create a new session object with the default timeout value, and link it */
+int fd_sess_new ( struct session ** session, char * diamId, char * opt, size_t optlen )
+{
+	char * sid = NULL;
+	size_t sidlen;
+	uint32_t hash;
+	struct session * sess;
+	struct fd_list * li;
+	int found = 0;
+	
+	TRACE_ENTRY("%p %p %p %d", session, diamId, opt, optlen);
+	CHECK_PARAMS( session && (diamId || opt) );
+	
+	/* Ok, first create the identifier for the string */
+	if (diamId == NULL) {
+		/* opt is the full string */
+		if (optlen) {
+			CHECK_MALLOC( sid = malloc(optlen + 1) );
+			strncpy(sid, opt, optlen);
+			sid[optlen] = '\0';
+			sidlen = optlen;
+		} else {
+			CHECK_MALLOC( sid = strdup(opt) );
+			sidlen = strlen(sid);
+		}
+	} else {
+		/* "<diamId>;<high32>;<low32>[;opt]" */
+		sidlen = strlen(diamId);
+		sidlen += 22; /* max size of ';<high32>;<low32>' */
+		if (opt)
+			sidlen += 1 + (optlen ?: strlen(opt)) ;
+		sidlen++; /* space for the final \0 also */
+		CHECK_MALLOC( sid = malloc(sidlen) );
+		CHECK_POSIX( pthread_mutex_lock(&sid_lock) );
+		if ( ++sid_l == 0 ) /* overflow */
+			++sid_h;
+		
+		if (opt) {
+			if (optlen)
+				sidlen = snprintf(sid, sidlen, "%s;%u;%u;%*.*s", diamId, sid_h, sid_l, optlen, optlen, opt);
+			else
+				sidlen = snprintf(sid, sidlen, "%s;%u;%u;%s", diamId, sid_h, sid_l, opt);
+		} else {
+			sidlen = snprintf(sid, sidlen, "%s;%u;%u", diamId, sid_h, sid_l);
+		}
+	
+		CHECK_POSIX( pthread_mutex_unlock(&sid_lock) );
+	}
+	
+	/* Initialize the session object now, to spend less time inside locked section later. 
+	 * Cons: we malloc then free if there is already a session with same SID; we could malloc later to avoid this. */
+	CHECK_MALLOC( sess = new_session(sid, sidlen) );
+	
+	/* Now find the place to add this object in the hash table. */
+	CHECK_POSIX( pthread_mutex_lock( H_LOCK(sess->hash) ) );
+	for (li = H_LIST(sess->hash)->next; li != H_LIST(sess->hash); li = li->next) {
+		int cmp;
+		struct session * s = (struct session *)(li->o);
+		
+		/* The list is ordered by hash and sid (in case of collisions) */
+		if (s->hash < sess->hash)
+			continue;
+		if (s->hash > sess->hash)
+			break;
+		
+		cmp = strcasecmp(s->sid, sess->sid);
+		if (cmp < 0)
+			continue;
+		if (cmp > 0)
+			break;
+		
+		/* A session with the same sid was already in the hash table */
+		found = 1;
+		*session = s;
+		break;
+	}
+	
+	/* If the session did not exist, we can add it into the hash table */
+	if (!found) {
+		fd_list_insert_before(li, &sess->chain_h);
+		
+		/* We must also insert in the expiry list */
+		CHECK_POSIX( pthread_mutex_lock( &exp_lock ) );
+		
+		/* Find the position in that list. We take it in reverse order */
+		for (li = exp_sentinel.prev; li != &exp_sentinel; li = li->prev) {
+			struct session * s = (struct session *)(li->o);
+			
+			if (TS_IS_INFERIOR( &s->timeout, &sess->timeout ) )
+				break;
+			
+			continue;
+		}
+		fd_list_insert_after( li, &sess->expire );
+		
+		/* We added a new expiring element, we must signal */
+		CHECK_POSIX( pthread_cond_signal(&exp_cond) );
+		
+		/* We're done */
+		CHECK_POSIX( pthread_mutex_unlock( &exp_lock ) );
+	}
+	
+	CHECK_POSIX( pthread_mutex_unlock( H_LOCK(sess->hash) ) );
+	
+	/* If a session already existed, we must destroy the new element */
+	if (found) {
+		CHECK_FCT( fd_sess_destroy( &sess ) ); /* we could avoid locking this time for optimization */
+		return EALREADY;
+	}
+	
+	*session = sess;
+	return 0;
+}
+
+/* Find or create a session */
+int fd_sess_fromsid ( char * sid, size_t len, struct session ** session, int * new)
+{
+	int ret;
+	
+	TRACE_ENTRY("%p %d %p %p", sid, len, session, new);
+	CHECK_PARAMS( sid && session );
+	
+	/* All the work is done in sess_new */
+	ret = fd_sess_new ( session, NULL, sid, len );
+	switch (ret) {
+		case 0:
+		case EALREADY:
+			break;
+		
+		default:
+			CHECK_FCT(ret);
+	}
+	
+	if (new)
+		*new = ret ? 0 : 1;
+	
+	return 0;
+}
+
+/* Get the sid of a session */
+int fd_sess_getsid ( struct session * session, char ** sid )
+{
+	TRACE_ENTRY("%p %p", session, sid);
+	
+	CHECK_PARAMS( VALIDATE_SI(session) && sid );
+	
+	*sid = session->sid;
+	
+	return 0;
+}
+
+/* Change the timeout value of a session */
+int fd_sess_settimeout( struct session * session, const struct timespec * timeout )
+{
+	struct fd_list * li;
+	
+	TRACE_ENTRY("%p %p", session, timeout);
+	CHECK_PARAMS( VALIDATE_SI(session) && timeout );
+	
+	/* Lock -- do we need to lock the hash table as well? I don't think so... */
+	CHECK_POSIX( pthread_mutex_lock( &exp_lock ) );
+	
+	/* Update the timeout */
+	fd_list_unlink(&session->expire);
+	memcpy(&session->timeout, timeout, sizeof(struct timespec));
+	
+	/* Find the new position in expire list. We take it in normal order */
+	for (li = exp_sentinel.next; li != &exp_sentinel; li = li->next) {
+		struct session * s = (struct session *)(li->o);
+
+		if (TS_IS_INFERIOR( &s->timeout, &session->timeout ) )
+			continue;
+
+		break;
+	}
+	fd_list_insert_before( li, &session->expire );
+
+	/* We added a new expiring element, we must signal */
+	CHECK_POSIX( pthread_cond_signal(&exp_cond) );
+
+	/* We're done */
+	CHECK_POSIX( pthread_mutex_unlock( &exp_lock ) );
+	
+	return 0;
+}
+
+/* Destroy a session immediatly */
+int fd_sess_destroy ( struct session ** session )
+{
+	struct session * sess;
+	
+	TRACE_ENTRY("%p", session);
+	CHECK_PARAMS( session && VALIDATE_SI(*session) );
+	
+	sess = *session;
+	*session = NULL;
+	
+	/* Unlink and invalidate */
+	CHECK_FCT( pthread_mutex_lock( H_LOCK(sess->hash) ) );
+	CHECK_FCT( pthread_mutex_lock( &exp_lock ) );
+	fd_list_unlink( &sess->chain_h );
+	fd_list_unlink( &sess->expire ); /* no need to signal the condition here */
+	sess->eyec = 0xdead;
+	CHECK_FCT( pthread_mutex_unlock( &exp_lock ) );
+	CHECK_FCT( pthread_mutex_unlock( H_LOCK(sess->hash) ) );
+	
+	/* Now destroy all states associated -- we don't take the lock since nobody can access this session anymore (in theory) */
+	while (!FD_IS_LIST_EMPTY(&sess->states)) {
+		struct state * st = (struct state *)(sess->states.next->o);
+		fd_list_unlink(&st->chain);
+		TRACE_DEBUG(FULL, "Calling handler %p cleanup for state registered with session '%s'", st->hdl, sess->sid);
+		(*st->hdl->cleanup)(sess->sid, st->state);
+		free(st);
+	}
+	
+	/* Finally, destroy the session itself */
+	free(sess->sid);
+	free(sess);
+	
+	return 0;
+}
+
+
+
+/* Save a state information with a session */
+int fd_sess_state_store ( struct session_handler * handler, struct session * session, session_state ** state )
+{
+	struct state *new;
+	struct fd_list * li;
+	int already = 0;
+	
+	TRACE_ENTRY("%p %p %p", handler, session, state);
+	CHECK_PARAMS( handler && VALIDATE_SH(handler) && session && VALIDATE_SI(session) && state );
+	
+	/* Lock the session state list */
+	CHECK_POSIX( pthread_mutex_lock(&session->stlock) );
+			
+	/* Create the new state object */
+	CHECK_MALLOC(new = malloc(sizeof(struct state)) );
+	memset(new, 0, sizeof(struct state));
+	
+	new->eyec = SD_EYEC;
+	new->state= *state;
+	fd_list_init(&new->chain, new);
+	new->hdl = handler;
+	
+	/* find place for this state in the list */
+	for (li = session->states.next; li != &session->states; li = li->next) {
+		struct state * st = (struct state *)(li->o);
+		/* The list is ordered by handler's id */
+		if (st->hdl->id < handler->id)
+			continue;
+		
+		if (st->hdl->id == handler->id) {
+			TRACE_DEBUG(INFO, "A state was already stored for session '%s' and handler '%p', at location %p", session->sid, st->hdl, st->state);
+			already = 1;
+		}
+		
+		break;
+	}
+	
+	if (!already) {
+		fd_list_insert_before(li, &new->chain);
+		*state = NULL;
+	} else {
+		free(new);
+	}
+	
+	CHECK_POSIX( pthread_mutex_unlock(&session->stlock) );
+	
+	return already ? EALREADY : 0;
+}
+
+/* Get the data back */
+int fd_sess_state_retrieve ( struct session_handler * handler, struct session * session, session_state ** state )
+{
+	struct fd_list * li;
+	struct state * st = NULL;
+	
+	TRACE_ENTRY("%p %p %p", handler, session, state);
+	CHECK_PARAMS( handler && VALIDATE_SH(handler) && session && VALIDATE_SI(session) && state );
+	
+	*state = NULL;
+	
+	/* Lock the session state list */
+	CHECK_POSIX( pthread_mutex_lock(&session->stlock) );
+	
+	/* find the state in the list */
+	for (li = session->states.next; li != &session->states; li = li->next) {
+		st = (struct state *)(li->o);
+		
+		/* The list is ordered by handler's id */
+		if (st->hdl->id > handler->id)
+			break;
+	}
+	
+	/* If we found the state */
+	if (st && (st->hdl == handler)) {
+		fd_list_unlink(&st->chain);
+		*state = st->state;
+		free(st);
+	}
+	
+	CHECK_POSIX( pthread_mutex_unlock(&session->stlock) );
+	
+	return 0;
+}
+
+
+
+/* Dump functions */
+void fd_sess_dump(int level, struct session * session)
+{
+	struct fd_list * li;
+	if (!TRACE_BOOL(level))
+		return;
+	
+	fd_log_debug("Session @%p:\n", session);
+	if (!VALIDATE_SI(session)) {
+		fd_log_debug("  Invalid session object\n");
+		return;
+	}
+		
+	fd_log_debug("  sid '%s', hash %x\n", session->sid, session->hash);
+	fd_log_debug("  timeout %d.%09d\n", session->timeout.tv_sec, session->timeout.tv_nsec);
+	
+	CHECK_POSIX_DO( pthread_mutex_lock(&session->stlock), /* ignore */ );
+	for (li = session->states.next; li != &session->states; li = li->next) {
+		struct state * st = (struct state *)(li->o);
+		fd_log_debug("    handler %d registered data %p\n", st->hdl->id, st->state);
+	}
+	CHECK_POSIX_DO( pthread_mutex_unlock(&session->stlock), /* ignore */ );
+}
+
+void fd_sess_dump_hdl(int level, struct session_handler * handler)
+{
+	if (!TRACE_BOOL(level))
+		return;
+	
+	fd_log_debug("Handler @%p:\n", handler);
+	if (!VALIDATE_SH(handler)) {
+		fd_log_debug("  Invalid session handler object\n");
+		return;
+	}
+		
+	fd_log_debug("  id %d, cleanup %p\n", handler->id, handler->cleanup);
+}