3 files changed, 134 insertions, 21 deletions

diff --git a/src/mds-server/client.c b/src/mds-server/client.c
index 6c46c90..3c8fb2d 100644
--- a/src/mds-server/client.c
+++ b/src/mds-server/client.c
@@ -57,6 +57,10 @@ void client_destroy(client_t* restrict this)
       mds_message_destroy(this->modify_message);
       free(this->modify_message);
     }
+  if (this->modify_mutex_created)
+    pthread_mutex_destroy(&(this->modify_mutex));
+  if (this->modify_cond_created)
+    pthread_cond_destroy(&(this->modify_cond));
   free(this);
 }
 
@@ -132,6 +136,8 @@ size_t client_unmarshal(client_t* restrict this, char* restrict data)
   this->multicasts = NULL;
   this->send_pending = NULL;
   this->mutex_created = 0;
+  this->modify_mutex_created = 0;
+  this->modify_cond_created = 0;
   this->multicasts_count = 0;
   buf_get_next(data, ssize_t, this->list_entry);
   buf_get_next(data, int, this->socket_fd);
diff --git a/src/mds-server/client.h b/src/mds-server/client.h
index 972ff84..2aeb813 100644
--- a/src/mds-server/client.h
+++ b/src/mds-server/client.h
@@ -112,6 +112,26 @@ typedef struct client
    */
   struct mds_message* modify_message;
   
+  /**
+   * Mutex for `modify_message` 
+   */
+  pthread_mutex_t modify_mutex;
+  
+  /**
+   * Condidition for `modify_message` 
+   */
+  pthread_cond_t modify_cond;
+  
+  /**
+   * Whether `modify_mutex` has been initialised
+   */
+  int modify_mutex_created;
+  
+  /**
+   * Whether `modify_cond` has been initialised
+   */
+  int modify_cond_created;
+  
 } client_t;
 
 
diff --git a/src/mds-server/mds-server.c b/src/mds-server/mds-server.c
index 8fbcd44..0c8ba92 100644
--- a/src/mds-server/mds-server.c
+++ b/src/mds-server/mds-server.c
@@ -493,6 +493,8 @@ void* slave_loop(void* data)
       information->send_pending = NULL;
       information->modify_message = NULL;
       information->mutex_created = 0;
+      information->modify_mutex_created = 0;
+      information->modify_cond_created = 0;
       
       /* Add to list of clients. */
       pthread_mutex_lock(&slave_mutex);
@@ -540,6 +542,20 @@ void* slave_loop(void* data)
     }
   information->mutex_created = 1;
   
+  /* Create mutex and codition for multicast interception replies. */
+  if ((errno = pthread_mutex_init(&(information->modify_mutex), NULL)) != 0)
+    {
+      perror(*argv);
+      goto fail;
+    }
+  information->modify_mutex_created = 1;
+  if ((errno = pthread_cond_init(&(information->modify_cond), NULL)) != 0)
+    {
+      perror(*argv);
+      goto fail;
+    }
+  information->modify_cond_created = 1;
+  
   
   /* Make the server update without all slaves dying on SIGUSR1. */
   if (xsigaction(SIGUSR1, sigusr1_trap) < 0)
@@ -683,7 +699,7 @@ void* slave_loop(void* data)
  * 
  * @param  client  The client has sent a message
  */
-void message_received(client_t* client) /* TODO Modify ID */
+void message_received(client_t* client)
 {
   mds_message_t message = client->message;
   int assign_id = 0;
@@ -692,6 +708,7 @@ void message_received(client_t* client) /* TODO Modify ID */
   int64_t priority = 0;
   int stop = 0;
   const char* message_id = NULL;
+  uint64_t modify_id = 0;
   size_t i, n;
   char* msgbuf;
   
@@ -706,9 +723,71 @@ void message_received(client_t* client) /* TODO Modify ID */
       else if (strequals(h,  "Stop: yes"))           stop       = 1;
       else if (startswith(h, "Message ID: "))        message_id = strstr(h, ": ") + 2;
       else if (startswith(h, "Priority: "))          priority   = atoll(strstr(h, ": ") + 2);
+      else if (startswith(h, "Modify ID: "))         modify_id  = (uint64_t)atoll(strstr(h, ": ") + 2);
+    }
+  
+  
+  /* Notify waiting client about a received message modification. */
+  if (modifying != 0)
+    {
+      /* pthread_cond_timedwait is required to handle re-exec because
+	 pthread_cond_timedwait and pthread_cond_wait ignore interruptions via signals. */
+      struct timespec timeout =
+	{
+	  .tv_sec = 1,
+	  .tv_nsec = 0
+	};
+      size_t address;
+      client_t* recipient;
+      mds_message_t* multicast;
+      
+      with_mutex(modify_mutex,
+		 while (hash_table_contains_key(&modify_map, (size_t)modify_id) == 0)
+		   {
+		     /* TODO support re-exec */
+		     pthread_cond_timedwait(&slave_cond, &slave_mutex, &timeout);
+		   }
+		 address = hash_table_get(&modify_map, (size_t)modify_id);
+		 recipient = (client_t*)(void*)address;
+		 if (xmalloc(multicast = recipient->modify_message, 1, mds_message_t))
+		   goto fail;
+		 multicast->headers = NULL;
+		 multicast->header_count = 0;
+		 multicast->payload = NULL;
+		 multicast->payload_size = 0;
+		 multicast->payload_ptr = 0;
+		 multicast->buffer = NULL;
+		 multicast->buffer_size = 0;
+		 multicast->buffer_ptr = 0;
+		 multicast->stage = 0;
+		 if (xmalloc(multicast->payload, message.payload_size, char))
+		   goto fail;
+		 memcpy(multicast->payload, message.payload, message.payload_size * sizeof(char));
+		 if (xmalloc(multicast->headers, message.header_count, char*))
+		   goto fail;
+		 for (i = 0; i < message.header_count; i++, multicast->header_count++)
+		   {
+		     multicast->headers[i] = strdup(message.headers[i]);
+		     if (multicast->headers[i] == NULL)
+		       goto fail;
+		   }
+		 goto done;
+	       fail:
+		 if (multicast != NULL)
+		   {
+		     mds_message_destroy(multicast);
+		     free(multicast);
+		     recipient->modify_message = NULL;
+		   }
+	       done:
+		 );
+      with_mutex(client->modify_mutex, pthread_cond_signal(&(client->modify_cond)););
+      
+      /* Do nothing more, not not even multicast this message. */
+      return;
     }
   
-  /* Ignore message if not labelled with a message ID. */
+  
   if (message_id == NULL)
     {
       eprint("received message with a message ID, ignoring.");
@@ -1292,6 +1371,11 @@ void multicast_message(multicast_t* multicast)
 			     hash_table_put(&modify_map, (size_t)modify_id, (size_t)(void*)client);
 			     pthread_cond_signal(&slave_cond);
 			   }
+		       }
+		     );
+	  with_mutex(client->modify_mutex,
+		     if (client->modify_message == NULL)
+		       {
 			 for (;;)
 			   {
 			     pthread_cond_timedwait(&slave_cond, &slave_mutex, &timeout);
@@ -1306,29 +1390,32 @@ void multicast_message(multicast_t* multicast)
 	    return;
 	  
 	  /* Act upon the reply. */
-	  mod = client->modify_message;
-	  for (i = 0; i < mod->header_count; i++)
-	    if (!strcmp(mod->headers[i], "Modify: yes"))
-	      {
-		modifying = 1;
-		break;
-	      }
-	  if (modifying)
+	  if (client->modify_message != NULL)
 	    {
-	      old_buf = multicast->message;
-	      n = mod->payload_size;
-	      multicast->message = realloc(old_buf, (multicast->message_prefix + n) * sizeof(char));
-	      if (multicast->message == NULL)
+	      mod = client->modify_message;
+	      for (i = 0; i < mod->header_count; i++)
+		if (!strcmp(mod->headers[i], "Modify: yes"))
+		  {
+		    modifying = 1;
+		    break;
+		  }
+	      if (modifying)
 		{
-		  perror(*argv);
-		  multicast->message = old_buf;
+		  old_buf = multicast->message;
+		  n = mod->payload_size;
+		  multicast->message = realloc(old_buf, (multicast->message_prefix + n) * sizeof(char));
+		  if (multicast->message == NULL)
+		    {
+		      perror(*argv);
+		      multicast->message = old_buf;
+		    }
+		  else
+		    memcpy(multicast->message + multicast->message_prefix, mod->payload, n);
 		}
-	      else
-		memcpy(multicast->message + multicast->message_prefix, mod->payload, n);
+	      
+	      /* Free the reply. */
+	      mds_message_destroy(client->modify_message);
 	    }
-	  
-	  /* Free the reply. */
-	  mds_message_destroy(client->modify_message);
 	}
       
       /* Reset how much of the message has been sent before we continue with next recipient. */