/*
 * Copyright 2001 Niels Provos <provos@citi.umich.edu>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#include <sys/types.h>
#include <sys/uio.h>
#include <errno.h>
#include <string.h>

#include "log.h"
#include "monitor.h"

int
mm_send_fd (int socket, int fd)
{
  struct msghdr msg;
  char tmp[CMSG_SPACE (sizeof (int))];
  struct cmsghdr *cmsg;
  struct iovec vec;
  char ch = '\0';
  ssize_t n;

  memset(&msg, 0, sizeof msg);
  msg.msg_control = (caddr_t)tmp;
  msg.msg_controllen = CMSG_LEN (sizeof (int));
  cmsg = CMSG_FIRSTHDR (&msg);
  cmsg->cmsg_len = CMSG_LEN (sizeof (int));
  cmsg->cmsg_level = SOL_SOCKET;
  cmsg->cmsg_type = SCM_RIGHTS;
  *(int *)CMSG_DATA (cmsg) = fd;

  vec.iov_base = &ch;
  vec.iov_len = 1;
  msg.msg_iov = &vec;
  msg.msg_iovlen = 1;

  if ((n = sendmsg (socket, &msg, 0)) == -1)
    {
      log_error ("%s: sendmsg(%d)", __func__, fd);
      return -1;
    }
  if (n != 1)
    {
      log_error ("%s: sendmsg: expected sent 1 got %ld", __func__, (long)n);
      return -1;
    }
  return 0;
}

int
mm_receive_fd (int socket)
{
  struct msghdr msg;
  char tmp[CMSG_SPACE (sizeof (int))];
  struct cmsghdr *cmsg;
  struct iovec vec;
  ssize_t n;
  char ch;
  int fd;

  memset (&msg, 0, sizeof msg);
  vec.iov_base = &ch;
  vec.iov_len = 1;
  msg.msg_iov = &vec;
  msg.msg_iovlen = 1;
  msg.msg_control = tmp;
  msg.msg_controllen = sizeof tmp;

  if ((n = recvmsg(socket, &msg, 0)) == -1)
    {
      log_error ("%s: recvmsg", __func__);
      return -1;
    }
  if (n != 1)
    {
      log_error ("%s: recvmsg: expected received 1 got %ld", __func__,
		 (long)n);
      return -1;
    }

  cmsg = CMSG_FIRSTHDR (&msg);
  if (cmsg->cmsg_type != SCM_RIGHTS)
    {
      log_error ("%s: expected type %d got %d", __func__, SCM_RIGHTS,
		 cmsg->cmsg_type);
      return -1;
    }
  fd = (*(int *)CMSG_DATA (cmsg));

  return fd;
}