viosocket.c

/*
   Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.

   This program 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; version 2 of
   the License.

   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   02110-1301  USA */

/*
  Note that we can't have assertion on file descriptors;  The reason for
  this is that during mysql shutdown, another thread can close a file
  we are working on.  In this case we should just return read errors from
  the file descriptior.
*/

#include "vio_priv.h"

#ifdef FIONREAD_IN_SYS_FILIO
# include <sys/filio.h>
#endif

int vio_errno(Vio *vio __attribute__((unused)))
{
  /* These transport types are not Winsock based. */
#ifdef _WIN32
  if (vio->type == VIO_TYPE_NAMEDPIPE ||
      vio->type == VIO_TYPE_SHARED_MEMORY)
    return GetLastError();
#endif

  /* Mapped to WSAGetLastError() on Win32. */
  return socket_errno;
}


int vio_socket_io_wait(Vio *vio, enum enum_vio_io_event event)
{
  int timeout, ret;

  DBUG_ASSERT(event == VIO_IO_EVENT_READ || event == VIO_IO_EVENT_WRITE);

  /* Choose an appropriate timeout. */
  if (event == VIO_IO_EVENT_READ)
    timeout= vio->read_timeout;
  else
    timeout= vio->write_timeout;

  /* Wait for input data to become available. */
  switch (vio_io_wait(vio, event, timeout))
  {
  case -1:
    /* Upon failure, vio_read/write() shall return -1. */
    ret= -1;
    break;
  case  0:
    /* The wait timed out. */
    ret= -1;
    break;
  default:
    /* A positive value indicates an I/O event. */
    ret= 0;
    break;
  }

  return ret;
}


/*
  Define a stub MSG_DONTWAIT if unavailable. In this case, fcntl
  (or a equivalent) is used to enable non-blocking operations.
  The flag must be supported in both send and recv operations.
*/
#if defined(__linux__)
#define VIO_USE_DONTWAIT  1
#define VIO_DONTWAIT      MSG_DONTWAIT
#else
#define VIO_DONTWAIT 0
#endif


size_t vio_read(Vio *vio, uchar *buf, size_t size)
{
  ssize_t ret;
  int flags= 0;
  DBUG_ENTER("vio_read");

  /* Ensure nobody uses vio_read_buff and vio_read simultaneously. */
  DBUG_ASSERT(vio->read_end == vio->read_pos);

  /* If timeout is enabled, do not block if data is unavailable. */
  if (vio->read_timeout >= 0)
    flags= VIO_DONTWAIT;

  while ((ret= mysql_socket_recv(vio->mysql_socket, (SOCKBUF_T *)buf, size, flags)) == -1)
  {
    int error= socket_errno;

    /* The operation would block? */
    if (error != SOCKET_EAGAIN && error != SOCKET_EWOULDBLOCK)
      break;

    /* Wait for input data to become available. */
    if ((ret= vio_socket_io_wait(vio, VIO_IO_EVENT_READ)))
      break;
  }

  DBUG_RETURN(ret);
}


/*
  Buffered read: if average read size is small it may
  reduce number of syscalls.
*/

size_t vio_read_buff(Vio *vio, uchar* buf, size_t size)
{
  size_t rc;
#define VIO_UNBUFFERED_READ_MIN_SIZE 2048
  DBUG_ENTER("vio_read_buff");
  DBUG_PRINT("enter", ("sd: %d  buf: 0x%lx  size: %u",
             mysql_socket_getfd(vio->mysql_socket), (long)buf, (uint)size));

  if (vio->read_pos < vio->read_end)
  {
    rc= MY_MIN((size_t) (vio->read_end - vio->read_pos), size);
    memcpy(buf, vio->read_pos, rc);
    vio->read_pos+= rc;
    /*
      Do not try to read from the socket now even if rc < size:
      vio_read can return -1 due to an error or non-blocking mode, and
      the safest way to handle it is to move to a separate branch.
    */
  }
  else if (size < VIO_UNBUFFERED_READ_MIN_SIZE)
  {
    rc= vio_read(vio, (uchar*) vio->read_buffer, VIO_READ_BUFFER_SIZE);
    if (rc != 0 && rc != (size_t) -1)
    {
      if (rc > size)
      {
        vio->read_pos= vio->read_buffer + size;
        vio->read_end= vio->read_buffer + rc;
        rc= size;
      }
      memcpy(buf, vio->read_buffer, rc);
    }
  }
  else
    rc= vio_read(vio, buf, size);
  DBUG_RETURN(rc);
#undef VIO_UNBUFFERED_READ_MIN_SIZE
}


my_bool vio_buff_has_data(Vio *vio)
{
  return (vio->read_pos != vio->read_end);
}


size_t vio_write(Vio *vio, const uchar* buf, size_t size)
{
  ssize_t ret;
  int flags= 0;
  DBUG_ENTER("vio_write");

  /* If timeout is enabled, do not block. */
  if (vio->write_timeout >= 0)
    flags= VIO_DONTWAIT;

  while ((ret= mysql_socket_send(vio->mysql_socket, (SOCKBUF_T *)buf, size, flags)) == -1)
  {
    int error= socket_errno;

    /* The operation would block? */
    if (error != SOCKET_EAGAIN && error != SOCKET_EWOULDBLOCK)
      break;

    /* Wait for the output buffer to become writable.*/
    if ((ret= vio_socket_io_wait(vio, VIO_IO_EVENT_WRITE)))
      break;
  }

  DBUG_RETURN(ret);
}

//WL#4896: Not covered
static int vio_set_blocking(Vio *vio, my_bool status)
{
  DBUG_ENTER("vio_set_blocking");

#ifdef _WIN32
  DBUG_ASSERT(vio->type != VIO_TYPE_NAMEDPIPE);
  DBUG_ASSERT(vio->type != VIO_TYPE_SHARED_MEMORY);
  {
    int ret;
    u_long arg= status ? 0 : 1;
    ret= ioctlsocket(mysql_socket_getfd(vio->mysql_socket), FIONBIO, &arg);
    DBUG_RETURN(ret);
  }
#else
  {
    int flags;

    if ((flags= fcntl(mysql_socket_getfd(vio->mysql_socket), F_GETFL, NULL)) < 0)
      DBUG_RETURN(-1);

    /*
      Always set/clear the flag to avoid inheritance issues. This is
      a issue mainly on Mac OS X Tiger (version 10.4) where although
      the O_NONBLOCK flag is inherited from the parent socket, the
      actual non-blocking behavior is not inherited.
    */
    if (status)
      flags&= ~O_NONBLOCK;
    else
      flags|= O_NONBLOCK;

    if (fcntl(mysql_socket_getfd(vio->mysql_socket), F_SETFL, flags) == -1)
      DBUG_RETURN(-1);
  }
#endif

  DBUG_RETURN(0);
}


int vio_socket_timeout(Vio *vio,
                       uint which __attribute__((unused)),
                       my_bool old_mode __attribute__((unused)))
{
  int ret= 0;
  DBUG_ENTER("vio_socket_timeout");

#if defined(_WIN32)
  {
    int optname;
    DWORD timeout= 0;
    const char *optval= (const char *) &timeout;

    /*
      The default socket timeout value is zero, which means an infinite
      timeout. Values less than 500 milliseconds are interpreted to be of
      500 milliseconds. Hence, the VIO behavior for zero timeout, which is
      intended to cause the send or receive operation to fail immediately
      if no data is available, is not supported on WIN32 and neither is
      necessary as it's not possible to set the VIO timeout value to zero.

      Assert that the VIO timeout is either positive or set to infinite.
    */
    DBUG_ASSERT(which || vio->read_timeout);
    DBUG_ASSERT(!which || vio->write_timeout);

    if (which)
    {
      optname= SO_SNDTIMEO;
      if (vio->write_timeout > 0)
        timeout= vio->write_timeout;
    }
    else
    {
      optname= SO_RCVTIMEO;
      if (vio->read_timeout > 0)
        timeout= vio->read_timeout;
    }

    ret= mysql_socket_setsockopt(vio->mysql_socket, SOL_SOCKET, optname,
                                     optval, sizeof(timeout));
  }
#else
  /*
    The MSG_DONTWAIT trick is not used with SSL sockets as the send and
    receive I/O operations are wrapped through SSL-specific functions
    (SSL_read and SSL_write) which are not equivalent to the standard
    recv(2) and send(2) used in vio_read() and vio_write(). Hence, the
    socket blocking mode is changed and vio_io_wait() is used to wait
    for I/O or timeout.
  */
#ifdef VIO_USE_DONTWAIT
  if (vio->type == VIO_TYPE_SSL)
#endif
  {
    /* Deduce what should be the new blocking mode of the socket. */
    my_bool new_mode= vio->write_timeout < 0 && vio->read_timeout < 0;

    /* If necessary, update the blocking mode. */
    if (new_mode != old_mode)
      ret= vio_set_blocking(vio, new_mode);
  }
#endif

  DBUG_RETURN(ret);
}


int vio_fastsend(Vio * vio __attribute__((unused)))
{
  int r=0;
  DBUG_ENTER("vio_fastsend");

#if defined(IPTOS_THROUGHPUT)
  {
    int tos = IPTOS_THROUGHPUT;
    r= mysql_socket_setsockopt(vio->mysql_socket, IPPROTO_IP, IP_TOS,
                                   (void *)&tos, sizeof(tos));
  }
#endif                                    /* IPTOS_THROUGHPUT */
  if (!r)
  {
#ifdef __WIN__
    BOOL nodelay= 1;
#else
    int nodelay = 1;
#endif

    r= mysql_socket_setsockopt(vio->mysql_socket, IPPROTO_TCP, TCP_NODELAY,
                  IF_WIN((const char*), (void*)) &nodelay,
                  sizeof(nodelay));

  }
  if (r)
  {
    DBUG_PRINT("warning", ("Couldn't set socket option for fast send"));
    r= -1;
  }
  DBUG_PRINT("exit", ("%d", r));
  DBUG_RETURN(r);
}

int vio_keepalive(Vio* vio, my_bool set_keep_alive)
{
  int r=0;
  uint opt = 0;
  DBUG_ENTER("vio_keepalive");
  DBUG_PRINT("enter", ("sd: %d  set_keep_alive: %d",
             mysql_socket_getfd(vio->mysql_socket), (int)set_keep_alive));
  if (vio->type != VIO_TYPE_NAMEDPIPE)
  {
    if (set_keep_alive)
      opt = 1;
    r = mysql_socket_setsockopt(vio->mysql_socket, SOL_SOCKET, SO_KEEPALIVE,
                                    (char *)&opt, sizeof(opt));
  }
  DBUG_RETURN(r);
}


my_bool
vio_should_retry(Vio *vio)
{
  return (vio_errno(vio) == SOCKET_EINTR);
}


my_bool
vio_was_timeout(Vio *vio)
{
  return (vio_errno(vio) == SOCKET_ETIMEDOUT);
}


int vio_shutdown(Vio * vio)
{
  int r=0;
  DBUG_ENTER("vio_shutdown");

 if (vio->inactive == FALSE)
  {
    DBUG_ASSERT(vio->type ==  VIO_TYPE_TCPIP ||
      vio->type == VIO_TYPE_SOCKET ||
      vio->type == VIO_TYPE_SSL);

    DBUG_ASSERT(mysql_socket_getfd(vio->mysql_socket) >= 0);
    if (mysql_socket_shutdown(vio->mysql_socket, SHUT_RDWR))
      r= -1;
    if (mysql_socket_close(vio->mysql_socket))
      r= -1;
  }
  if (r)
  {
    DBUG_PRINT("vio_error", ("close() failed, error: %d",socket_errno));
    /* FIXME: error handling (not critical for MySQL) */
  }
  vio->inactive= TRUE;
  vio->mysql_socket= MYSQL_INVALID_SOCKET;
  DBUG_RETURN(r);
}


const char *vio_description(Vio * vio)
{
  if (!vio->desc[0])
  {
    my_snprintf(vio->desc, VIO_DESCRIPTION_SIZE,
                (vio->type == VIO_TYPE_SOCKET ? "socket (%d)" : "TCP/IP (%d)"),
                mysql_socket_getfd(vio->mysql_socket));
  }
  return vio->desc;
}

enum enum_vio_type vio_type(Vio* vio)
{
  return vio->type;
}

my_socket vio_fd(Vio* vio)
{
  return mysql_socket_getfd(vio->mysql_socket);
}

static void vio_get_normalized_ip(const struct sockaddr *src,
                                  int src_length,
                                  struct sockaddr *dst,
                                  int *dst_length)
{
  switch (src->sa_family) {
  case AF_INET:
    memcpy(dst, src, src_length);
    *dst_length= src_length;
    break;

#ifdef HAVE_IPV6
  case AF_INET6:
  {
    const struct sockaddr_in6 *src_addr6= (const struct sockaddr_in6 *) src;
    const struct in6_addr *src_ip6= &(src_addr6->sin6_addr);
    const uint32 *src_ip6_int32= (uint32 *) src_ip6->s6_addr;

    if (IN6_IS_ADDR_V4MAPPED(src_ip6) || IN6_IS_ADDR_V4COMPAT(src_ip6))
    {
      struct sockaddr_in *dst_ip4= (struct sockaddr_in *) dst;

      /*
        This is an IPv4-mapped or IPv4-compatible IPv6 address. It should
        be converted to the IPv4 form.
      */

      *dst_length= sizeof (struct sockaddr_in);

      memset(dst_ip4, 0, *dst_length);
      dst_ip4->sin_family= AF_INET;
      dst_ip4->sin_port= src_addr6->sin6_port;

      /*
        In an IPv4 mapped or compatible address, the last 32 bits represent
        the IPv4 address. The byte orders for IPv6 and IPv4 addresses are
        the same, so a simple copy is possible.
      */
      dst_ip4->sin_addr.s_addr= src_ip6_int32[3];
    }
    else
    {
      /* This is a "native" IPv6 address. */

      memcpy(dst, src, src_length);
      *dst_length= src_length;
    }

    break;
  }
#endif /* HAVE_IPV6 */
  }
}


my_bool vio_get_normalized_ip_string(const struct sockaddr *addr,
                                     int addr_length,
                                     char *ip_string,
                                     size_t ip_string_size)
{
  struct sockaddr_storage norm_addr_storage;
  struct sockaddr *norm_addr= (struct sockaddr *) &norm_addr_storage;
  int norm_addr_length;
  int err_code;

  vio_get_normalized_ip(addr, addr_length, norm_addr, &norm_addr_length);

  err_code= vio_getnameinfo(norm_addr, ip_string, ip_string_size, NULL, 0,
                            NI_NUMERICHOST);

  if (!err_code)
    return FALSE;

  DBUG_PRINT("error", ("getnameinfo() failed with %d (%s).",
                       (int) err_code,
                       (const char *) gai_strerror(err_code)));
  return TRUE;
}


my_bool vio_peer_addr(Vio *vio, char *ip_buffer, uint16 *port,
                      size_t ip_buffer_size)
{
  DBUG_ENTER("vio_peer_addr");
  DBUG_PRINT("enter", ("Client socked fd: %d",
            (int)mysql_socket_getfd(vio->mysql_socket)));

  if (vio->localhost)
  {
    /*
      Initialize vio->remote and vio->addLen. Set vio->remote to IPv4 loopback
      address.
    */
    struct in_addr *ip4= &((struct sockaddr_in *) &(vio->remote))->sin_addr;

    vio->remote.ss_family= AF_INET;
    vio->addrLen= sizeof (struct sockaddr_in);

    ip4->s_addr= htonl(INADDR_LOOPBACK);

    /* Initialize ip_buffer and port. */

    strmov(ip_buffer, "127.0.0.1");
    *port= 0;
  }
  else
  {
    int err_code;
    char port_buffer[NI_MAXSERV];

    struct sockaddr_storage addr_storage;
    struct sockaddr *addr= (struct sockaddr *) &addr_storage;
    size_socket addr_length= sizeof (addr_storage);

    /* Get sockaddr by socked fd. */

    err_code= mysql_socket_getpeername(vio->mysql_socket, addr, &addr_length);

    if (err_code)
    {
      DBUG_PRINT("exit", ("getpeername() gave error: %d", socket_errno));
      DBUG_RETURN(TRUE);
    }

    /* Normalize IP address. */

    vio_get_normalized_ip(addr, addr_length,
                          (struct sockaddr *) &vio->remote, &vio->addrLen);

    /* Get IP address & port number. */

    err_code= vio_getnameinfo((struct sockaddr *) &vio->remote,
                              ip_buffer, ip_buffer_size,
                              port_buffer, NI_MAXSERV,
                              NI_NUMERICHOST | NI_NUMERICSERV);

    if (err_code)
    {
      DBUG_PRINT("exit", ("getnameinfo() gave error: %s",
                          gai_strerror(err_code)));
      DBUG_RETURN(TRUE);
    }

    *port= (uint16) strtol(port_buffer, NULL, 10);
  }

  DBUG_PRINT("exit", ("Client IP address: %s; port: %d",
                      (const char *) ip_buffer,
                      (int) *port));
  DBUG_RETURN(FALSE);
}


// WL#4896: Not covered
static my_bool socket_peek_read(Vio *vio, uint *bytes)
{
  my_socket sd= mysql_socket_getfd(vio->mysql_socket);
#if defined(_WIN32)
  int len;
  if (ioctlsocket(sd, FIONREAD, &len))
    return TRUE;
  *bytes= len;
  return FALSE;
#elif defined(FIONREAD_IN_SYS_IOCTL) || defined(FIONREAD_IN_SYS_FILIO)
  int len;
  if (ioctl(sd, FIONREAD, &len) < 0)
    return TRUE;
  *bytes= len;
  return FALSE;
#else
  char buf[1024];
  ssize_t res= recv(sd, &buf, sizeof(buf), MSG_PEEK);
  if (res < 0)
    return TRUE;
  *bytes= res;
  return FALSE;
#endif
}

#ifndef _WIN32

/*
  Linux specific flag used to detect connection shutdown. The flag is
  also used for half-closed notification, which here is interpreted as
  if there is data available to be read from the socket.
*/
#ifndef POLLRDHUP
#define POLLRDHUP 0
#endif

/* Data may be read. */
#define MY_POLL_SET_IN      (POLLIN | POLLPRI)
/* Data may be written. */
#define MY_POLL_SET_OUT     (POLLOUT)
/* An error or hangup. */
#define MY_POLL_SET_ERR     (POLLERR | POLLHUP | POLLNVAL)

#endif

#if !defined(_WIN32) && !defined(__APPLE__)
int vio_io_wait(Vio *vio, enum enum_vio_io_event event, int timeout)
{
  int ret;
  short revents= 0;
  struct pollfd pfd;
  my_socket sd= mysql_socket_getfd(vio->mysql_socket);
  MYSQL_SOCKET_WAIT_VARIABLES(locker, state) /* no ';' */
  DBUG_ENTER("vio_io_wait");

  memset(&pfd, 0, sizeof(pfd));

  pfd.fd= sd;

  /*
    Set the poll bitmask describing the type of events.
    The error flags are only valid in the revents bitmask.
  */
  switch (event)
  {
  case VIO_IO_EVENT_READ:
    pfd.events= MY_POLL_SET_IN;
    revents= MY_POLL_SET_IN | MY_POLL_SET_ERR | POLLRDHUP;
    break;
  case VIO_IO_EVENT_WRITE:
  case VIO_IO_EVENT_CONNECT:
    pfd.events= MY_POLL_SET_OUT;
    revents= MY_POLL_SET_OUT | MY_POLL_SET_ERR;
    break;
  }

  MYSQL_START_SOCKET_WAIT(locker, &state, vio->mysql_socket, PSI_SOCKET_SELECT, 0);

  /*
    Wait for the I/O event and return early in case of
    error or timeout.
  */
  switch ((ret= poll(&pfd, 1, timeout)))
  {
  case -1:
    /* On error, -1 is returned. */
    break;
  case 0:
    /*
      Set errno to indicate a timeout error.
      (This is not compiled in on WIN32.)
    */
    errno= SOCKET_ETIMEDOUT;
    break;
  default:
    /* Ensure that the requested I/O event has completed. */
    DBUG_ASSERT(pfd.revents & revents);
    break;
  }

  MYSQL_END_SOCKET_WAIT(locker, 0);
  DBUG_RETURN(ret);
}

#else

int vio_io_wait(Vio *vio, enum enum_vio_io_event event, int timeout)
{
  int ret;
  struct timeval tm;
  my_socket fd= mysql_socket_getfd(vio->mysql_socket);
  fd_set readfds, writefds, exceptfds;
  MYSQL_SOCKET_WAIT_VARIABLES(locker, state) /* no ';' */
  DBUG_ENTER("vio_io_wait");

  /* Convert the timeout, in milliseconds, to seconds and microseconds. */
  if (timeout >= 0)
  {
    tm.tv_sec= timeout / 1000;
    tm.tv_usec= (timeout % 1000) * 1000;
  }

  FD_ZERO(&readfds);
  FD_ZERO(&writefds);
  FD_ZERO(&exceptfds);

  /* Always receive notification of exceptions. */
  FD_SET(fd, &exceptfds);

  switch (event)
  {
  case VIO_IO_EVENT_READ:
    /* Readiness for reading. */
    FD_SET(fd, &readfds);
    break;
  case VIO_IO_EVENT_WRITE:
  case VIO_IO_EVENT_CONNECT:
    /* Readiness for writing. */
    FD_SET(fd, &writefds);
    break;
  }

  MYSQL_START_SOCKET_WAIT(locker, &state, vio->mysql_socket, PSI_SOCKET_SELECT, 0);

  /* The first argument is ignored on Windows. */
  ret= select(fd + 1, &readfds, &writefds, &exceptfds, 
              (timeout >= 0) ? &tm : NULL);

  MYSQL_END_SOCKET_WAIT(locker, 0);

  /* Set error code to indicate a timeout error. */
  if (ret == 0)
#if defined(_WIN32)
    WSASetLastError(SOCKET_ETIMEDOUT);
#elif defined(__APPLE__)
    errno= SOCKET_ETIMEDOUT;
#else
#error Oops...Wrong OS
#endif

  /* Error or timeout? */
  if (ret <= 0)
    DBUG_RETURN(ret);

  /* The requested I/O event is ready? */
  switch (event)
  {
  case VIO_IO_EVENT_READ:
    ret= test(FD_ISSET(fd, &readfds));
    break;
  case VIO_IO_EVENT_WRITE:
  case VIO_IO_EVENT_CONNECT:
    ret= test(FD_ISSET(fd, &writefds));
    break;
  }

  /* Error conditions pending? */
  ret|= test(FD_ISSET(fd, &exceptfds));

  /* Not a timeout, ensure that a condition was met. */
  DBUG_ASSERT(ret);

  DBUG_RETURN(ret);
}

#endif /* _WIN32 */


my_bool
vio_socket_connect(Vio *vio, struct sockaddr *addr, socklen_t len, int timeout)
{
  int ret, wait;
  DBUG_ENTER("vio_socket_connect");

  /* Only for socket-based transport types. */
  DBUG_ASSERT(vio->type == VIO_TYPE_SOCKET || vio->type == VIO_TYPE_TCPIP);

  /* If timeout is not infinite, set socket to non-blocking mode. */
  if ((timeout > -1) && vio_set_blocking(vio, FALSE))
    DBUG_RETURN(TRUE);

  /* Initiate the connection. */
  ret= mysql_socket_connect(vio->mysql_socket, addr, len);

#ifdef _WIN32
  wait= (ret == SOCKET_ERROR) &&
        (WSAGetLastError() == WSAEINPROGRESS ||
         WSAGetLastError() == WSAEWOULDBLOCK);
#else
  wait= (ret == -1) && (errno == EINPROGRESS || errno == EALREADY);
#endif

  /*
    The connection is in progress. The vio_io_wait() call can be used
    to wait up to a specified period of time for the connection to
    succeed.

    If vio_io_wait() returns 0 (after waiting however many seconds),
    the socket never became writable (host is probably unreachable.)
    Otherwise, if vio_io_wait() returns 1, then one of two conditions
    exist:

    1. An error occurred. Use getsockopt() to check for this.
    2. The connection was set up successfully: getsockopt() will
       return 0 as an error.
  */
  if (wait && (vio_io_wait(vio, VIO_IO_EVENT_CONNECT, timeout) == 1))
  {
    int error;
    IF_WIN(int, socklen_t) optlen= sizeof(error);
    IF_WIN(char, void) *optval= (IF_WIN(char, void) *) &error;

    /*
      At this point, we know that something happened on the socket.
      But this does not means that everything is alright. The connect
      might have failed. We need to retrieve the error code from the
      socket layer. We must return success only if we are sure that
      it was really a success. Otherwise we might prevent the caller
      from trying another address to connect to.
    */
    if (!(ret= mysql_socket_getsockopt(vio->mysql_socket, SOL_SOCKET, SO_ERROR, optval, &optlen)))
    {
#ifdef _WIN32
      WSASetLastError(error);
#else
      errno= error;
#endif
      ret= test(error);
    }
  }

  /* If necessary, restore the blocking mode, but only if connect succeeded. */
  if ((timeout > -1) && (ret == 0))
  {
    if (vio_set_blocking(vio, TRUE))
      DBUG_RETURN(TRUE);
  }

  DBUG_RETURN(test(ret));
}


my_bool vio_is_connected(Vio *vio)
{
  uint bytes= 0;
  DBUG_ENTER("vio_is_connected");

  /*
    The first step of detecting an EOF condition is verifying
    whether there is data to read. Data in this case would be
    the EOF. An exceptional condition event and/or errors are
    interpreted as if there is data to read.
  */
  if (!vio_io_wait(vio, VIO_IO_EVENT_READ, 0))
    DBUG_RETURN(TRUE);

  /*
    The second step is read() or recv() from the socket returning
    0 (EOF). Unfortunately, it's not possible to call read directly
    as we could inadvertently read meaningful connection data.
    Simulate a read by retrieving the number of bytes available to
    read -- 0 meaning EOF. In the presence of unrecoverable errors,
    the socket is assumed to be disconnected.
  */
  while (socket_peek_read(vio, &bytes))
  {
    if (socket_errno != SOCKET_EINTR)
      DBUG_RETURN(FALSE);
  }

#ifdef HAVE_OPENSSL
  /* There might be buffered data at the SSL layer. */
  if (!bytes && vio->type == VIO_TYPE_SSL)
    bytes= SSL_pending((SSL*) vio->ssl_arg);
#endif

  DBUG_RETURN(bytes ? TRUE : FALSE);
}

#ifndef DBUG_OFF

ssize_t vio_pending(Vio *vio)
{
  uint bytes= 0;

  /* Data pending on the read buffer. */
  if (vio->read_pos < vio->read_end)
    return vio->read_end - vio->read_pos;

  /* Skip non-socket based transport types. */
  if (vio->type == VIO_TYPE_TCPIP || vio->type == VIO_TYPE_SOCKET)
  {
    /* Obtain number of readable bytes in the socket buffer. */
    if (socket_peek_read(vio, &bytes))
      return -1;
  }

  /*
    SSL not checked due to a yaSSL bug in SSL_pending that
    causes it to attempt to read from the socket.
  */

  return (ssize_t) bytes;
}

#endif

my_bool vio_is_no_name_error(int err_code)
{
#ifdef _WIN32

  return err_code == WSANO_DATA || err_code == EAI_NONAME;

#else

  return err_code == EAI_NONAME;

#endif
}


int vio_getnameinfo(const struct sockaddr *sa,
                    char *hostname, size_t hostname_size,
                    char *port, size_t port_size,
                    int flags)
{
  int sa_length= 0;

  switch (sa->sa_family) {
  case AF_INET:
    sa_length= sizeof (struct sockaddr_in);
#ifdef HAVE_SOCKADDR_IN_SIN_LEN
    ((struct sockaddr_in *) sa)->sin_len= sa_length;
#endif /* HAVE_SOCKADDR_IN_SIN_LEN */
    break;

#ifdef HAVE_IPV6
  case AF_INET6:
    sa_length= sizeof (struct sockaddr_in6);
# ifdef HAVE_SOCKADDR_IN6_SIN6_LEN
    ((struct sockaddr_in6 *) sa)->sin6_len= sa_length;
# endif /* HAVE_SOCKADDR_IN6_SIN6_LEN */
    break;
#endif /* HAVE_IPV6 */
  }

  return getnameinfo(sa, sa_length,
                     hostname, hostname_size,
                     port, port_size,
                     flags);
}