/*

 * svc_tcp.c, Server side for TCP/IP based RPC.

 *

 * Copyright (C) 2012-2018 Free Software Foundation, Inc.

 * This file is part of the GNU C Library.

 *

 * The GNU C Library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * The GNU C Library 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with the GNU C Library; if not, see

 * <http://www.gnu.org/licenses/>.

 *

 * Copyright (c) 2010, Oracle America, Inc.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are

 * met:

 *

 *     * Redistributions of source code must retain the above copyright

 *       notice, this list of conditions and the following disclaimer.

 *     * 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.

 *     * Neither the name of the "Oracle America, Inc." nor the names of its

 *       contributors may be used to endorse or promote products derived

 *       from this software without specific prior written permission.

 *

 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 *   "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

 *   COPYRIGHT HOLDER OR CONTRIBUTORS 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.

 *

 * Actually implements two flavors of transporter -

 * a tcp rendezvouser (a listener and connection establisher)

 * and a record/tcp stream.

 */

#include <stdio.h>

#include <unistd.h>

#include <string.h>

#include <libintl.h>

#include <rpc/rpc.h>

#include <sys/socket.h>

#include <sys/poll.h>

#include <errno.h>

#include <stdlib.h>

#include <wchar.h>

#include <libio/iolibio.h>

#include <shlib-compat.h>

/*

 * Ops vector for TCP/IP based rpc service handle

 */

static bool_t svctcp_recv (SVCXPRT *, struct rpc_msg *);

static enum xprt_stat svctcp_stat (SVCXPRT *);

static bool_t svctcp_getargs (SVCXPRT *, xdrproc_t, caddr_t);

static bool_t svctcp_reply (SVCXPRT *, struct rpc_msg *);

static bool_t svctcp_freeargs (SVCXPRT *, xdrproc_t, caddr_t);

static void svctcp_destroy (SVCXPRT *);

static const struct xp_ops svctcp_op =

{

  svctcp_recv,

  svctcp_stat,

  svctcp_getargs,

  svctcp_reply,

  svctcp_freeargs,

  svctcp_destroy

};

/*

 * Ops vector for TCP/IP rendezvous handler

 */

static bool_t rendezvous_request (SVCXPRT *, struct rpc_msg *);

static enum xprt_stat rendezvous_stat (SVCXPRT *);

static void svctcp_rendezvous_abort (void) __attribute__ ((__noreturn__));

/* This function makes sure abort() relocation goes through PLT

   and thus can be lazy bound.  */

static void

svctcp_rendezvous_abort (void)

{

  abort ();

};

static const struct xp_ops svctcp_rendezvous_op =

{

  rendezvous_request,

  rendezvous_stat,

  (bool_t (*) (SVCXPRT *, xdrproc_t, caddr_t)) svctcp_rendezvous_abort,

  (bool_t (*) (SVCXPRT *, struct rpc_msg *)) svctcp_rendezvous_abort,

  (bool_t (*) (SVCXPRT *, xdrproc_t, caddr_t)) svctcp_rendezvous_abort,

  svctcp_destroy

};

static int readtcp (char*, char *, int);

static int writetcp (char *, char *, int);

static SVCXPRT *makefd_xprt (int, u_int, u_int);

struct tcp_rendezvous

  {				/* kept in xprt->xp_p1 */

    u_int sendsize;

    u_int recvsize;

  };

struct tcp_conn

  {				/* kept in xprt->xp_p1 */

    enum xprt_stat strm_stat;

    u_long x_id;

    XDR xdrs;

    char verf_body[MAX_AUTH_BYTES];

  };

/*

 * Usage:

 *      xprt = svctcp_create(sock, send_buf_size, recv_buf_size);

 *

 * Creates, registers, and returns a (rpc) tcp based transporter.

 * Once *xprt is initialized, it is registered as a transporter

 * see (svc.h, xprt_register).  This routine returns

 * a NULL if a problem occurred.

 *

 * If sock<0 then a socket is created, else sock is used.

 * If the socket, sock is not bound to a port then svctcp_create

 * binds it to an arbitrary port.  The routine then starts a tcp

 * listener on the socket's associated port.  In any (successful) case,

 * xprt->xp_sock is the registered socket number and xprt->xp_port is the

 * associated port number.

 *

 * Since tcp streams do buffered io similar to stdio, the caller can specify

 * how big the send and receive buffers are via the second and third parms;

 * 0 => use the system default.

 */

SVCXPRT *

svctcp_create (int sock, u_int sendsize, u_int recvsize)

{

  bool_t madesock = FALSE;

  SVCXPRT *xprt;

  struct tcp_rendezvous *r;

  struct sockaddr_in addr;

  socklen_t len = sizeof (struct sockaddr_in);

  if (sock == RPC_ANYSOCK)

    {

      if ((sock = __socket (AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)

	{

	  perror (_("svc_tcp.c - tcp socket creation problem"));

	  return (SVCXPRT *) NULL;

	}

      madesock = TRUE;

    }

  memset ((char *) &addr, 0, sizeof (addr));

  addr.sin_family = AF_INET;

  if (bindresvport (sock, &addr))

    {

      addr.sin_port = 0;

      (void) __bind (sock, (struct sockaddr *) &addr, len);

    }

  if ((__getsockname (sock, (struct sockaddr *) &addr, &len) != 0) ||

      (__listen (sock, SOMAXCONN) != 0))

    {

      perror (_("svc_tcp.c - cannot getsockname or listen"));

      if (madesock)

	(void) __close (sock);

      return (SVCXPRT *) NULL;

    }

  r = (struct tcp_rendezvous *) mem_alloc (sizeof (*r));

  xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));

  if (r == NULL || xprt == NULL)

    {

      (void) __fxprintf (NULL, "%s: %s", __func__, _("out of memory\n"));

      mem_free (r, sizeof (*r));

      mem_free (xprt, sizeof (SVCXPRT));

      return NULL;

    }

  r->sendsize = sendsize;

  r->recvsize = recvsize;

  xprt->xp_p2 = NULL;

  xprt->xp_p1 = (caddr_t) r;

  xprt->xp_verf = _null_auth;

  xprt->xp_ops = &svctcp_rendezvous_op;

  xprt->xp_port = ntohs (addr.sin_port);

  xprt->xp_sock = sock;

  xprt_register (xprt);

  return xprt;

}

#ifdef EXPORT_RPC_SYMBOLS

libc_hidden_def (svctcp_create)

#else

libc_hidden_nolink_sunrpc (svctcp_create, GLIBC_2_0)

#endif

/*

 * Like svtcp_create(), except the routine takes any *open* UNIX file

 * descriptor as its first input.

 */

SVCXPRT *

svcfd_create (int fd, u_int sendsize, u_int recvsize)

{

  return makefd_xprt (fd, sendsize, recvsize);

}

libc_hidden_nolink_sunrpc (svcfd_create, GLIBC_2_0)

static SVCXPRT *

makefd_xprt (int fd, u_int sendsize, u_int recvsize)

{

  SVCXPRT *xprt;

  struct tcp_conn *cd;

  xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));

  cd = (struct tcp_conn *) mem_alloc (sizeof (struct tcp_conn));

  if (xprt == (SVCXPRT *) NULL || cd == NULL)

    {

      (void) __fxprintf (NULL, "%s: %s", "svc_tcp: makefd_xprt",

			 _("out of memory\n"));

      mem_free (xprt, sizeof (SVCXPRT));

      mem_free (cd, sizeof (struct tcp_conn));

      return NULL;

    }

  cd->strm_stat = XPRT_IDLE;

  xdrrec_create (&(cd->xdrs), sendsize, recvsize,

		 (caddr_t) xprt, readtcp, writetcp);

  xprt->xp_p2 = NULL;

  xprt->xp_p1 = (caddr_t) cd;

  xprt->xp_verf.oa_base = cd->verf_body;

  xprt->xp_addrlen = 0;

  xprt->xp_ops = &svctcp_op;	/* truly deals with calls */

  xprt->xp_port = 0;		/* this is a connection, not a rendezvouser */

  xprt->xp_sock = fd;

  xprt_register (xprt);

  return xprt;

}

static bool_t

rendezvous_request (SVCXPRT *xprt, struct rpc_msg *errmsg)

{

  int sock;

  struct tcp_rendezvous *r;

  struct sockaddr_in addr;

  socklen_t len;

  r = (struct tcp_rendezvous *) xprt->xp_p1;

again:

  len = sizeof (struct sockaddr_in);

  if ((sock = accept (xprt->xp_sock, (struct sockaddr *) &addr, &len)) < 0)

    {

      if (errno == EINTR)

	goto again;

      __svc_accept_failed ();

      return FALSE;

    }

  /*

   * make a new transporter (re-uses xprt)

   */

  xprt = makefd_xprt (sock, r->sendsize, r->recvsize);

  memcpy (&xprt->xp_raddr, &addr, sizeof (addr));

  xprt->xp_addrlen = len;

  return FALSE;		/* there is never an rpc msg to be processed */

}

static enum xprt_stat

rendezvous_stat (SVCXPRT *xprt)

{

  return XPRT_IDLE;

}

static void

svctcp_destroy (SVCXPRT *xprt)

{

  struct tcp_conn *cd = (struct tcp_conn *) xprt->xp_p1;

  xprt_unregister (xprt);

  (void) __close (xprt->xp_sock);

  if (xprt->xp_port != 0)

    {

      /* a rendezvouser socket */

      xprt->xp_port = 0;

    }

  else

    {

      /* an actual connection socket */

      XDR_DESTROY (&(cd->xdrs));

    }

  mem_free ((caddr_t) cd, sizeof (struct tcp_conn));

  mem_free ((caddr_t) xprt, sizeof (SVCXPRT));

}

/*

 * reads data from the tcp connection.

 * any error is fatal and the connection is closed.

 * (And a read of zero bytes is a half closed stream => error.)

 */

static int

readtcp (char *xprtptr, char *buf, int len)

{

  SVCXPRT *xprt = (SVCXPRT *)xprtptr;

  int sock = xprt->xp_sock;

  int milliseconds = 35 * 1000;

  struct pollfd pollfd;

  do

    {

      pollfd.fd = sock;

      pollfd.events = POLLIN;

      switch (__poll (&pollfd, 1, milliseconds))

	{

	case -1:

	  if (errno == EINTR)

	    continue;

	  /*FALLTHROUGH*/

	case 0:

	  goto fatal_err;

	default:

	  if ((pollfd.revents & POLLERR) || (pollfd.revents & POLLHUP)

	      || (pollfd.revents & POLLNVAL))

	    goto fatal_err;

	  break;

	}

    }

  while ((pollfd.revents & POLLIN) == 0);

  if ((len = __read (sock, buf, len)) > 0)

    return len;

 fatal_err:

  ((struct tcp_conn *) (xprt->xp_p1))->strm_stat = XPRT_DIED;

  return -1;

}

/*

 * writes data to the tcp connection.

 * Any error is fatal and the connection is closed.

 */

static int

writetcp (char *xprtptr, char * buf, int len)

{

  SVCXPRT *xprt = (SVCXPRT *)xprtptr;

  int i, cnt;

  for (cnt = len; cnt > 0; cnt -= i, buf += i)

    {

      if ((i = __write (xprt->xp_sock, buf, cnt)) < 0)

	{

	  ((struct tcp_conn *) (xprt->xp_p1))->strm_stat = XPRT_DIED;

	  return -1;

	}

    }

  return len;

}

static enum xprt_stat

svctcp_stat (SVCXPRT *xprt)

{

  struct tcp_conn *cd =

  (struct tcp_conn *) (xprt->xp_p1);

  if (cd->strm_stat == XPRT_DIED)

    return XPRT_DIED;

  if (!xdrrec_eof (&(cd->xdrs)))

    return XPRT_MOREREQS;

  return XPRT_IDLE;

}

static bool_t

svctcp_recv (SVCXPRT *xprt, struct rpc_msg *msg)

{

  struct tcp_conn *cd = (struct tcp_conn *) (xprt->xp_p1);

  XDR *xdrs = &(cd->xdrs);

  xdrs->x_op = XDR_DECODE;

  (void) xdrrec_skiprecord (xdrs);

  if (xdr_callmsg (xdrs, msg))

    {

      cd->x_id = msg->rm_xid;

      return TRUE;

    }

  cd->strm_stat = XPRT_DIED;	/* XXXX */

  return FALSE;

}

static bool_t

svctcp_getargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)

{

  return ((*xdr_args) (&(((struct tcp_conn *)

			  (xprt->xp_p1))->xdrs), args_ptr));

}

static bool_t

svctcp_freeargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)

{

  XDR *xdrs = &(((struct tcp_conn *) (xprt->xp_p1))->xdrs);

  xdrs->x_op = XDR_FREE;

  return ((*xdr_args) (xdrs, args_ptr));

}

static bool_t

svctcp_reply (SVCXPRT *xprt, struct rpc_msg *msg)

{

  struct tcp_conn *cd = (struct tcp_conn *) (xprt->xp_p1);

  XDR *xdrs = &(cd->xdrs);

  bool_t stat;

  xdrs->x_op = XDR_ENCODE;

  msg->rm_xid = cd->x_id;

  stat = xdr_replymsg (xdrs, msg);

  (void) xdrrec_endofrecord (xdrs, TRUE);

  return stat;

}