rbug_connection.c

/*
 * Copyright 2009 VMware, Inc.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, and/or sell copies of the Software, and to permit persons to whom
 * the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
 * VMWARE AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include "rbug.h"
#include "rbug_internal.h"

#include "util/u_network.h"

struct rbug_connection
{
   int socket;
   uint32_t send_serial;
   uint32_t recv_serial;
   enum rbug_opcode opcode;
};

/**
 * Create a rbug connection from a socket created with u_socket.
 *
 * Result:
 *    A new allocated connection using socket as communication path
 */
struct rbug_connection *
rbug_from_socket(int socket)
{
   struct rbug_connection *c = CALLOC_STRUCT(rbug_connection);
   c->socket = socket;
   return c;
}

/**
 * Free a connection, also closes socket.
 */
void
rbug_disconnect(struct rbug_connection *c)
{
   u_socket_close(c->socket);
   FREE(c);
}

/**
 * Waits for a message to be fully received.
 * Also returns the serial for the message, serial is not touched for replys.
 *
 * Result:
 *    demarshaled message on success, NULL on connection error
 */
struct rbug_header *
rbug_get_message(struct rbug_connection *c, uint32_t *serial)
{
   struct rbug_proto_header header;
   struct rbug_header *out;
   struct rbug_proto_header *data;
   size_t length = 0;
   size_t read = 0;
   int ret;


   ret = u_socket_peek(c->socket, &header, sizeof(header));
   if (ret <= 0) {
      return NULL;
   }

   length = (size_t)header.length * 4;
   data = MALLOC(length);
   if (!data) {
      return NULL;
   }
   data->opcode = 0;

   do {
      uint8_t *ptr = ((uint8_t*)data) + read;
      ret = u_socket_recv(c->socket, ptr, length - read);

      if (ret <= 0) {
         FREE(data);
         return NULL;
      }

      read += ret;
   } while(read < length);

   out = rbug_demarshal(data);
   if (!out)
      FREE(data);
   else if (serial)
      *serial = c->recv_serial++;
   else
      c->recv_serial++;

   return out;
}

/**
 * Frees a message and associated data.
 */
void
rbug_free_header(struct rbug_header *header)
{
   if (!header)
      return;

   FREE(header->__message);
   FREE(header);
}

/**
 * Internal function used by rbug_send_* functions.
 *
 * Start sending a message.
 */
int
rbug_connection_send_start(struct rbug_connection *c, enum rbug_opcode opcode, uint32_t length)
{
   c->opcode = opcode;
   return 0;
}

/**
 * Internal function used by rbug_send_* functions.
 *
 * Write data to the socket.
 */
int
rbug_connection_write(struct rbug_connection *c, void *to, uint32_t size)
{
   int ret = u_socket_send(c->socket, to, size);
   return ret;
}

/**
 * Internal function used by rbug_send_* functions.
 *
 * Finish writing data to the socket.
 * Ups the send_serial and sets the serial argument if supplied.
 */
int rbug_connection_send_finish(struct rbug_connection *c, uint32_t *serial)
{
   if (c->opcode < 0)
      return 0;
   else if (serial)
      *serial = c->send_serial++;
   else
      c->send_serial++;

   return 0;
}