Imported Upstream version 0.9.3upstream/0.9.3

1 files changed, 899 insertions, 0 deletions

diff --git a/src/lockmanager/gnunet-service-lockmanager.c b/src/lockmanager/gnunet-service-lockmanager.c
new file mode 100644
index 0000000..8ec9889
--- /dev/null
+++ b/src/lockmanager/gnunet-service-lockmanager.c
@@ -0,0 +1,899 @@
+/*
+  This file is part of GNUnet.
+  (C) 2012 Christian Grothoff (and other contributing authors)
+
+  GNUnet is free 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 2, or (at your
+  option) any later version.
+
+  GNUnet 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 GNUnet; see the file COPYING.  If not, write to the
+  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+  Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file lockmanager/gnunet-service-lockmanager.c
+ * @brief implementation of the LOCKMANAGER service
+ * @author Sree Harsha Totakura
+ */
+
+#include "platform.h"
+#include "gnunet_common.h"
+#include "gnunet_container_lib.h"
+#include "gnunet_protocols.h"
+#include "gnunet_service_lib.h"
+#include "gnunet_server_lib.h"
+
+#include "lockmanager.h"
+
+
+#define LOG(kind,...)                           \
+  GNUNET_log (kind, __VA_ARGS__)
+
+#define TIME_REL_MINS(min)                                      \
+  GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, min)
+
+#define TIMEOUT TIME_REL_MINS(3)
+
+
+/**
+ * Doubly linked list of clients having connections to us
+ */
+struct ClientList;
+
+
+/**
+ * Doubly linked list of clients waiting for a lock
+ */
+struct WaitList
+{
+  /**
+   * The next client structure
+   */
+  struct WaitList *next;
+  
+  /**
+   * The prev client structure
+   */
+  struct WaitList *prev;
+
+  /**
+   * Pointer to the client
+   */
+  struct ClientList *cl_entry;
+};
+
+
+/**
+ * Structure representing a Lock
+ */
+struct Lock
+{
+  /**
+   * List head of clients waiting for this lock
+   */
+  struct WaitList *wl_head;
+
+  /**
+   * List tail of clients waiting for this lock
+   */
+  struct WaitList *wl_tail;
+
+  /**
+   * The client which is currently holding this lock
+   */
+  struct ClientList *cl_entry;
+
+  /**
+   * The name of the locking domain this lock belongs to
+   */
+  char *domain_name;
+
+  /**
+   * The number of this lock
+   */
+  uint32_t lock_num;
+};
+
+
+/**
+ * A Lock element for a doubly linked list
+ */
+struct LockList
+{
+  /**
+   * The next element pointer
+   */
+  struct LockList *next;
+
+  /**
+   * Pointer to the previous element
+   */
+  struct LockList *prev;
+
+  /**
+   * Pointer to the Lock
+   */
+  struct Lock *lock;
+};
+
+
+/**
+ * Doubly linked list of clients having connections to us
+ */
+struct ClientList
+{
+
+  /**
+   * The next client structure
+   */
+  struct ClientList *next;
+
+  /**
+   * The previous client structure
+   */
+  struct ClientList *prev;
+
+  /**
+   * Head of the doubly linked list of the currently held locks by this client
+   */
+  struct LockList *ll_head;
+
+  /**
+   * Tail of the doubly linked list of the currently held locks by this client
+   */
+  struct LockList *ll_tail;
+
+  /**
+   * Pointer to the client
+   */
+  struct GNUNET_SERVER_Client *client;
+};
+
+
+/**
+ * Structure for matching a lock
+ */
+struct LockMatch
+{
+  /**
+   * The matched LockingRequest entry; Should be NULL if no entry is found
+   */
+  struct Lock *matched_entry;
+
+  /**
+   * The locking domain name of the lock
+   */
+  const char *domain_name;
+
+  /**
+   * The lock number
+   */
+  uint32_t lock_num;
+};
+
+
+/**
+ * Map of lock-keys to the 'struct LockList' entry for the key.
+ */
+static struct GNUNET_CONTAINER_MultiHashMap *lock_map;
+
+/**
+ * Head of the doubly linked list of clients currently connected
+ */
+static struct ClientList *cl_head;
+
+/**
+ * Tail of the doubly linked list of clients currently connected
+ */
+static struct ClientList *cl_tail;
+
+
+/**
+ * Get the key for the given lock in the 'lock_map'.
+ *
+ * @param domain_name
+ * @param lock_number
+ * @param key set to the key
+ */
+static void
+get_key (const char *domain_name,
+	 uint32_t lock_number,
+	 struct GNUNET_HashCode *key)
+{
+  uint32_t *last_32;
+
+  GNUNET_CRYPTO_hash (domain_name,
+		      strlen (domain_name),
+		      key);
+  last_32 = (uint32_t *) key;
+  *last_32 ^= lock_number;
+}
+
+
+/**
+ * Hashmap iterator for matching a lock
+ *
+ * @param cls the LockMatch structure
+ * @param key current key code
+ * @param value value in the hash map (struct Lock)
+ * @return GNUNET_YES if we should continue to
+ *         iterate,
+ *         GNUNET_NO if not. 
+ */
+static int
+match_iterator (void *cls, const GNUNET_HashCode *key, void *value)
+{
+  struct LockMatch *match = cls;
+  struct Lock *lock = value;
+
+  if ( (match->lock_num == lock->lock_num) 
+       && (0 == strcmp (match->domain_name, lock->domain_name)) )
+  {
+    match->matched_entry = lock;    
+    return GNUNET_NO;
+  }
+  return GNUNET_YES;
+}
+
+
+/**
+ * Function to search for a lock in the global lock hashmap
+ *
+ * @param domain_name the name of the locking domain
+ * @param lock_num the number of the lock
+ * @return the lock if found; NULL if not
+ */
+static struct Lock *
+find_lock (const char *domain_name,
+           const uint32_t lock_num)
+              
+{
+  struct LockMatch match;
+  struct GNUNET_HashCode key;
+
+  match.lock_num = lock_num;
+  match.domain_name = domain_name;
+  match.matched_entry = NULL;
+  get_key (domain_name, lock_num, &key);
+  GNUNET_CONTAINER_multihashmap_get_multiple (lock_map,
+                                              &key,
+                                              &match_iterator,
+                                              &match);
+  return match.matched_entry;
+}
+
+
+/**
+ * Adds a lock to the global lock hashmap
+ *
+ * @param domain_name the name of the lock's locking domain
+ * @param lock_num the lock number
+ * @return pointer to the lock structure which is added to lock map
+ */
+static struct Lock *
+add_lock (const char *domain_name, 
+          uint32_t lock_num)
+{
+  struct Lock *lock;
+  struct GNUNET_HashCode key;
+  size_t domain_name_len;
+
+  lock = GNUNET_malloc (sizeof (struct Lock));
+  domain_name_len = strlen (domain_name) + 1;
+  lock->domain_name = GNUNET_malloc (domain_name_len);
+  strncpy (lock->domain_name, domain_name, domain_name_len);
+  lock->lock_num = lock_num;
+  get_key (domain_name, lock_num, &key);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Adding a lock with num: %d and domain: %s to the lock map\n",
+       lock->lock_num, lock->domain_name);
+  GNUNET_CONTAINER_multihashmap_put (lock_map,
+                                     &key,
+                                     lock,
+                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
+  return lock;
+}
+
+
+/**
+ * Removes a lock from the lock map. The WaitList of the lock should be empty
+ *
+ * @param lock the lock to remove
+ */
+static void
+remove_lock (struct Lock *lock)
+{
+  struct GNUNET_HashCode key;
+  
+  GNUNET_assert (NULL == lock->wl_head);
+  get_key (lock->domain_name,
+           lock->lock_num,
+           &key);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Removing lock with num: %u, domain: %s from lock map\n",
+       lock->lock_num, lock->domain_name);
+  GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove
+                 (lock_map, &key, lock));
+  GNUNET_free (lock->domain_name);
+  GNUNET_free (lock);
+}
+
+
+/**
+ * Find the LockList entry corresponding to the given Lock in a ClientList
+ * entry
+ *
+ * @param cl_entry the ClientList entry whose lock list has to be searched
+ * @param lock the lock which has to be matched
+ * @return the matching LockList entry; NULL if no match is found
+ */
+static struct LockList *
+cl_ll_find_lock (struct ClientList *cl_entry,
+                 const struct Lock *lock)
+{
+  struct LockList *ll_entry;
+
+  for (ll_entry = cl_entry->ll_head;
+       NULL != ll_entry; ll_entry = ll_entry->next)
+  {
+    if (lock == ll_entry->lock)
+      return ll_entry;
+  }
+  return NULL;
+}
+
+
+/**
+ * Function to append a lock to the lock list of a ClientList entry
+ *
+ * @param cl_entry the client which currently owns this lock
+ * @param lock the lock to be added to the cl_entry's lock list
+ */
+static void
+cl_ll_add_lock (struct ClientList *cl_entry,
+                struct Lock *lock)
+{
+  struct LockList *ll_entry;
+
+  ll_entry = GNUNET_malloc (sizeof (struct LockList));
+  ll_entry->lock = lock;
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Adding a lock with num: %u and domain: %s to lock list\n",
+       lock->lock_num, lock->domain_name);
+  GNUNET_CONTAINER_DLL_insert_tail (cl_entry->ll_head,
+                                    cl_entry->ll_tail,
+                                    ll_entry);
+}
+
+
+/**
+ * Function to delete a lock from the lock list of the given ClientList entry
+ *
+ * @param cl_entry the ClientList entry
+ * @param ll_entry the LockList entry to be deleted
+ */
+static void
+cl_ll_remove_lock (struct ClientList *cl_entry,
+                   struct LockList *ll_entry)
+{
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Removing lock with num: %u, domain: %s from lock list of a client\n",
+       ll_entry->lock->lock_num,
+       ll_entry->lock->domain_name);
+  GNUNET_assert (NULL != cl_entry->ll_head);
+  GNUNET_CONTAINER_DLL_remove (cl_entry->ll_head,
+                               cl_entry->ll_tail,
+                               ll_entry);
+  GNUNET_free (ll_entry);
+}
+
+
+/**
+ * Find a WaitList entry in the waiting list of a lock
+ *
+ * @param lock the lock whose wait list has to be searched
+ * @param cl_entry the ClientList entry to be searched
+ * @return the WaitList entry matching the given cl_entry; NULL if not match
+ *           was found
+ */
+static struct WaitList *
+lock_wl_find (const struct Lock *lock,
+              const struct ClientList *cl_entry)
+{
+  struct WaitList *wl_entry;
+
+  for (wl_entry = lock->wl_head;
+       NULL != wl_entry; 
+       wl_entry = wl_entry->next)
+  {
+    if (cl_entry == wl_entry->cl_entry)
+      return wl_entry;
+  }
+  return NULL;
+}
+
+
+/**
+ * Add a client to the wait list of given lock
+ *
+ * @param lock the lock list entry of a lock
+ * @param cl_entry the client to queue for the lock's wait list
+ */
+static void
+lock_wl_add_client (struct Lock *lock,
+                    struct ClientList *cl_entry)
+{
+  struct WaitList *wl_entry;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Adding a client to lock's wait list (lock num: %u, domain: %s)\n",
+       lock->lock_num,
+       lock->domain_name);
+  wl_entry = GNUNET_malloc (sizeof (struct WaitList));
+  wl_entry->cl_entry = cl_entry;
+  GNUNET_CONTAINER_DLL_insert_tail (lock->wl_head,
+                                    lock->wl_tail,
+                                    wl_entry);
+}
+
+
+/**
+ * Remove an entry from the wait list of the given lock
+ *
+ * @param lock the lock
+ * @param wl_entry the wait list entry to be removed
+ */
+static void
+lock_wl_remove (struct Lock *lock,
+                struct WaitList *wl_entry)
+{
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Removing client from wait list of lock with num: %u, domain: %s\n",
+       lock->lock_num, lock->domain_name);
+  GNUNET_CONTAINER_DLL_remove (lock->wl_head,
+                               lock->wl_tail,
+                               wl_entry);
+  GNUNET_free (wl_entry);
+}
+
+
+/**
+ * Search for a client in the client list
+ *
+ * @param client the client to be searched for
+ * @return the ClientList entry; NULL if the client is not found
+ */
+static struct ClientList *
+cl_find_client (const struct GNUNET_SERVER_Client *client)                
+{
+  struct ClientList *current;
+
+  for (current = cl_head; NULL != current; current = current->next)
+    if (client == current->client)
+      return current;
+  return NULL;
+}
+
+
+/**
+ * Append a client to the client list
+ *
+ * @param client the client to be appended to the list
+ * @return the client list entry which is added to the client list
+ */
+static struct ClientList *
+cl_add_client (struct GNUNET_SERVER_Client *client)
+{
+  struct ClientList *new_client;
+  
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Adding a client to the client list\n");
+  new_client = GNUNET_malloc (sizeof (struct ClientList));
+  GNUNET_SERVER_client_keep (client);
+  new_client->client = client;
+  GNUNET_CONTAINER_DLL_insert_tail (cl_head,
+                                    cl_tail,
+                                    new_client);
+  return new_client;
+}
+
+
+/**
+ * Delete the given client from the client list. The LockList should be empty
+ *
+ * @param cl_entry the client list entry to delete
+ */
+static void
+cl_remove_client (struct ClientList *cl_entry)
+{
+  GNUNET_assert (NULL == cl_entry->ll_head);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Removing a client from the client list\n");
+  GNUNET_SERVER_client_drop (cl_entry->client);
+  GNUNET_CONTAINER_DLL_remove (cl_head,
+                               cl_tail,
+                               cl_entry);
+  GNUNET_free (cl_entry);
+}
+
+
+/**
+ * Transmit notify for sending message to client
+ *
+ * @param cls the message to send
+ * @param size number of bytes available in buf
+ * @param buf where the callee should write the message
+ * @return number of bytes written to buf
+ */
+static size_t 
+transmit_notify (void *cls, size_t size, void *buf)
+{
+  struct GNUNET_LOCKMANAGER_Message *msg = cls;
+  uint16_t msg_size;
+
+  if ((0 == size) || (NULL == buf))
+  {
+    /* FIXME: Timed out -- requeue? */
+    return 0;
+  }
+  msg_size = ntohs (msg->header.size);
+  GNUNET_assert (size >= msg_size);
+  memcpy (buf, msg, msg_size);
+  GNUNET_free (msg);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Message of size %u sent\n", msg_size);
+  return msg_size;
+}
+
+
+/**
+ * Send SUCCESS message to the client
+ *
+ * @param client the client to which the message has to be sent
+ * @param domain_name the locking domain of the successfully acquried lock
+ * @param lock_num the number of the successfully acquired lock
+ */
+static void
+send_success_msg (struct GNUNET_SERVER_Client *client,
+                  const char *domain_name,
+                  int lock_num)
+{
+  struct GNUNET_LOCKMANAGER_Message *reply;
+  size_t domain_name_len;
+  uint16_t reply_size;
+
+  domain_name_len = strlen (domain_name) + 1;
+  reply_size = sizeof (struct GNUNET_LOCKMANAGER_Message) + domain_name_len;
+  reply = GNUNET_malloc (reply_size);
+  reply->header.size = htons (reply_size);
+  reply->header.type = htons (GNUNET_MESSAGE_TYPE_LOCKMANAGER_SUCCESS);
+  reply->lock = htonl (lock_num);
+  strncpy ((char *) &reply[1], domain_name, domain_name_len);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Sending SUCCESS message for lock with num: %u, domain: %s\n",
+       lock_num, domain_name);
+  GNUNET_SERVER_notify_transmit_ready (client,
+                                       reply_size,
+                                       TIMEOUT,
+                                       &transmit_notify,
+                                       reply);
+}
+
+
+/**
+ * Handler for GNUNET_MESSAGE_TYPE_LOCKMANAGER_ACQUIRE
+ *
+ * @param cls NULL
+ * @param client the client sending this message
+ * @param message GNUNET_MESSAGE_TYPE_LOCKMANAGER_ACQUIRE message
+ */
+static void
+handle_acquire (void *cls,
+                struct GNUNET_SERVER_Client *client,
+                const struct GNUNET_MessageHeader *message)
+{
+  const struct GNUNET_LOCKMANAGER_Message *request;
+  const char *domain_name;
+  struct Lock *lock;
+  struct ClientList *cl_entry;
+  uint32_t lock_num;
+  uint16_t msize;
+
+  msize = htons (message->size);
+  if (msize <= sizeof (struct GNUNET_LOCKMANAGER_Message))
+  {
+    GNUNET_break (0);
+    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    return;
+  }
+  request = (struct GNUNET_LOCKMANAGER_Message *) message;
+  domain_name = (const char *) &request[1];
+  msize -= sizeof (struct GNUNET_LOCKMANAGER_Message);
+  if ('\0' != domain_name[msize])
+  {
+    GNUNET_break (0);
+    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    return;
+  }
+  lock_num = ntohl (request->lock);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Received an ACQUIRE message for lock num: %u domain: %s\n",
+       lock_num, domain_name);
+  if (NULL == (cl_entry = cl_find_client (client))) 
+    cl_entry = cl_add_client (client); /* Add client if not in client list */
+  if (NULL != (lock = find_lock (domain_name,lock_num)))
+  {
+    if (lock->cl_entry == cl_entry)
+    {                         /* Client is requesting a lock it already owns */
+      GNUNET_break (0);
+      GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+      return;
+    }
+    lock_wl_add_client (lock, cl_entry);
+    cl_ll_add_lock (cl_entry, lock);
+  }
+  else                          /* Lock not present */
+  {
+    lock = add_lock (domain_name, lock_num);
+    lock->cl_entry = cl_entry;
+    cl_ll_add_lock (cl_entry, lock);
+    send_success_msg (cl_entry->client, domain_name, lock_num);
+  }
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+}
+
+
+/**
+ * This function gives the lock to the first client in the wait list of the
+ * lock. If no clients are currently waiting for this lock, the lock is then
+ * destroyed.
+ *
+ * @param lock the lock which has to be processed for release
+ */
+static void
+process_lock_release (struct Lock *lock)
+{
+  struct WaitList *wl_entry;
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Processing lock release for lock with num: %u, domain: %s\n",
+       lock->lock_num, lock->domain_name);
+  wl_entry = lock->wl_head;
+  if (NULL == wl_entry)
+  {
+    remove_lock (lock);   /* No clients waiting for this lock - delete */
+    return;
+  }
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Giving lock to a client from wait list\n");
+  lock->cl_entry = wl_entry->cl_entry;
+  lock_wl_remove(lock, wl_entry);
+  send_success_msg (lock->cl_entry->client,
+                    lock->domain_name,
+                    lock->lock_num);
+  return;
+}
+
+
+/**
+ * Handle for GNUNET_MESSAGE_TYPE_LOCKMANAGER_RELEASE
+ *
+ * @param cls NULL
+ * @param client the client sending this message
+ * @param message the LOCKMANAGER_RELEASE message
+ */
+static void
+handle_release (void *cls,
+                struct GNUNET_SERVER_Client *client,
+                const struct GNUNET_MessageHeader *message)
+{
+  const struct GNUNET_LOCKMANAGER_Message *request;
+  struct ClientList *cl_entry;
+  struct WaitList *wl_entry;
+  struct LockList *ll_entry;
+  const char *domain_name;
+  struct Lock *lock;
+  uint32_t lock_num;
+  uint16_t msize;
+
+  msize = ntohs (message->size);
+  if (msize <= sizeof (struct GNUNET_LOCKMANAGER_Message))
+  { 
+    GNUNET_break (0);
+    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    return;
+  }
+  request = (const struct GNUNET_LOCKMANAGER_Message *) message;
+  domain_name = (const char *) &request[1];
+  msize -= sizeof (struct GNUNET_LOCKMANAGER_Message);
+  if ('\0' != domain_name[msize-1])
+  {
+    GNUNET_break (0);
+    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    return;
+  
+
+  }
+  lock_num = ntohl (request->lock);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Received RELEASE message for lock with num: %d, domain: %s\n",
+       lock_num, domain_name);
+  if (NULL == (cl_entry = cl_find_client (client)))
+  {
+    GNUNET_break(0);
+    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    return;
+  }
+  lock = find_lock (domain_name, lock_num);
+  if(NULL == lock)
+  {    
+    GNUNET_break (0);
+    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    return;
+  }
+  if (NULL == (ll_entry = cl_ll_find_lock (cl_entry, lock)))
+  {
+    GNUNET_break (0);
+    GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
+    return;
+  }
+  cl_ll_remove_lock (cl_entry, ll_entry);
+  if (cl_entry == lock->cl_entry)
+  {
+    process_lock_release (lock);
+    GNUNET_SERVER_receive_done (client, GNUNET_OK);
+    return;
+  }
+  /* remove 'client' from wait list (check that it is not there...) */
+  if (NULL != (wl_entry = lock_wl_find (lock, cl_entry)))
+  {
+    lock_wl_remove (lock, wl_entry);
+  }
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+}
+
+
+/**
+ * Callback for client disconnect
+ *
+ * @param cls NULL
+ * @param client the client which has disconnected
+ */
+static void
+client_disconnect_cb (void *cls, struct GNUNET_SERVER_Client *client)
+{
+  struct ClientList *cl_entry;
+  struct LockList *ll_entry;
+  struct Lock *lock;
+
+  if (NULL == client)
+    return;
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "A client has been disconnected -- freeing its locks and resources\n"); 
+  cl_entry = cl_find_client (client);
+  if (NULL == cl_entry)
+    return;
+  while (NULL != (ll_entry = cl_entry->ll_head))
+  {
+    lock = ll_entry->lock;
+    cl_ll_remove_lock (cl_entry, ll_entry);
+    process_lock_release (lock);
+  }
+  cl_remove_client (cl_entry);
+}
+
+
+/**
+ * Hashmap Iterator to delete lock entries in hash map
+ *
+ * @param cls NULL
+ * @param key current key code
+ * @param value value in the hash map
+ * @return GNUNET_YES if we should continue to
+ *         iterate,
+ *         GNUNET_NO if not.
+ */
+static int 
+lock_delete_iterator (void *cls,
+                      const GNUNET_HashCode * key,
+                      void *value)
+{
+  struct Lock *lock = value;
+
+  GNUNET_assert (NULL != lock);
+  while (NULL != lock->wl_head)
+  {
+    lock_wl_remove (lock, lock->wl_head);
+  }
+  GNUNET_assert (GNUNET_YES == 
+                 GNUNET_CONTAINER_multihashmap_remove(lock_map,
+                                                      key,
+                                                      lock));
+  GNUNET_free (lock->domain_name);
+  GNUNET_free (lock);
+  return GNUNET_YES;
+}
+
+
+/**
+ * Task to clean up and shutdown nicely
+ *
+ * @param cls NULL
+ * @param tc the TaskContext from scheduler
+ */
+static void
+shutdown_task (void *cls,
+               const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Shutting down lock manager\n");
+  /* Clean the global ClientList */
+  while (NULL != cl_head)
+  {
+    while (NULL != cl_head->ll_head) /* Clear the LockList */
+    {
+      cl_ll_remove_lock (cl_head, cl_head->ll_head);
+    }
+    cl_remove_client (cl_head);
+  }
+  /* Clean the global hash table */
+  GNUNET_CONTAINER_multihashmap_iterate (lock_map,
+                                         &lock_delete_iterator,
+                                         NULL);
+  GNUNET_assert (0 == GNUNET_CONTAINER_multihashmap_size (lock_map));
+  GNUNET_CONTAINER_multihashmap_destroy (lock_map);
+}
+
+
+/**
+ * Lock manager setup
+ *
+ * @param cls closure
+ * @param server the initialized server
+ * @param cfg configuration to use
+ */
+static void 
+lockmanager_run (void *cls,
+                 struct GNUNET_SERVER_Handle * server,
+                 const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  static const struct GNUNET_SERVER_MessageHandler message_handlers[] =
+    {
+      {&handle_acquire, NULL, GNUNET_MESSAGE_TYPE_LOCKMANAGER_ACQUIRE, 0},
+      {&handle_release, NULL, GNUNET_MESSAGE_TYPE_LOCKMANAGER_RELEASE, 0},
+      {NULL}
+    };
+  GNUNET_SERVER_add_handlers (server,
+                              message_handlers);
+  GNUNET_SERVER_disconnect_notify (server,
+                                   &client_disconnect_cb,
+                                   NULL);
+  lock_map = GNUNET_CONTAINER_multihashmap_create (30);
+  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
+                                &shutdown_task,
+                                NULL);
+}
+
+
+/**
+ * The starting point of execution
+ */
+int main (int argc, char *const *argv)
+{
+  return
+    (GNUNET_OK ==
+     GNUNET_SERVICE_run (argc,
+                         argv,
+                         "lockmanager",
+                         GNUNET_SERVICE_OPTION_NONE,
+                         &lockmanager_run,
+                         NULL)) ? 0 : 1;
+}