/*

 * svc.c, Server-side remote procedure call interface.

 *

 * There are two sets of procedures here.  The xprt routines are

 * for handling transport handles.  The svc routines handle the

 * list of service routines.

 *  Copyright (C) 2002-2018 Free Software Foundation, Inc.

 *  This file is part of the GNU C Library.

 *  Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.

 *

 *  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.

 */

#include <errno.h>

#include <unistd.h>

#include <rpc/rpc.h>

#include <rpc/svc.h>

#include <rpc/pmap_clnt.h>

#include <sys/poll.h>

#include <time.h>

#include <shlib-compat.h>

#define xports RPC_THREAD_VARIABLE(svc_xports_s)

#define NULL_SVC ((struct svc_callout *)0)

#define	RQCRED_SIZE	400	/* this size is excessive */

/* The services list

   Each entry represents a set of procedures (an rpc program).

   The dispatch routine takes request structs and runs the

   appropriate procedure. */

struct svc_callout {

  struct svc_callout *sc_next;

  rpcprog_t sc_prog;

  rpcvers_t sc_vers;

  void (*sc_dispatch) (struct svc_req *, SVCXPRT *);

  bool_t sc_mapped;

};

#define svc_head RPC_THREAD_VARIABLE(svc_head_s)

/* ***************  SVCXPRT related stuff **************** */

/* Activate a transport handle. */

void

xprt_register (SVCXPRT *xprt)

{

  register int sock = xprt->xp_sock;

  register int i;

  if (xports == NULL)

    {

      xports = (SVCXPRT **) calloc (_rpc_dtablesize (), sizeof (SVCXPRT *));

      if (xports == NULL) /* Don't add handle */

	return;

    }

  if (sock < _rpc_dtablesize ())

    {

      struct pollfd *new_svc_pollfd;

      xports[sock] = xprt;

      if (sock < FD_SETSIZE)

	FD_SET (sock, &svc_fdset);

      /* Check if we have an empty slot */

      for (i = 0; i < svc_max_pollfd; ++i)

	if (svc_pollfd[i].fd == -1)

	  {

	    svc_pollfd[i].fd = sock;

	    svc_pollfd[i].events = (POLLIN | POLLPRI |

				    POLLRDNORM | POLLRDBAND);

	    return;

	  }

      new_svc_pollfd = (struct pollfd *) realloc (svc_pollfd,

						  sizeof (struct pollfd)

						  * (svc_max_pollfd + 1));

      if (new_svc_pollfd == NULL) /* Out of memory */

	return;

      svc_pollfd = new_svc_pollfd;

      ++svc_max_pollfd;

      svc_pollfd[svc_max_pollfd - 1].fd = sock;

      svc_pollfd[svc_max_pollfd - 1].events = (POLLIN | POLLPRI |

					       POLLRDNORM | POLLRDBAND);

    }

}

libc_hidden_nolink_sunrpc (xprt_register, GLIBC_2_0)

/* De-activate a transport handle. */

void

xprt_unregister (SVCXPRT *xprt)

{

  register int sock = xprt->xp_sock;

  register int i;

  if ((sock < _rpc_dtablesize ()) && (xports[sock] == xprt))

    {

      xports[sock] = (SVCXPRT *) 0;

      if (sock < FD_SETSIZE)

	FD_CLR (sock, &svc_fdset);

      for (i = 0; i < svc_max_pollfd; ++i)

	if (svc_pollfd[i].fd == sock)

	  svc_pollfd[i].fd = -1;

    }

}

#ifdef EXPORT_RPC_SYMBOLS

libc_hidden_def (xprt_unregister)

#else

libc_hidden_nolink_sunrpc (xprt_unregister, GLIBC_2_0)

#endif

/* ********************** CALLOUT list related stuff ************* */

/* Search the callout list for a program number, return the callout

   struct. */

static struct svc_callout *

svc_find (rpcprog_t prog, rpcvers_t vers, struct svc_callout **prev)

{

  register struct svc_callout *s, *p;

  p = NULL_SVC;

  for (s = svc_head; s != NULL_SVC; s = s->sc_next)

    {

      if ((s->sc_prog == prog) && (s->sc_vers == vers))

	goto done;

      p = s;

    }

done:

  *prev = p;

  return s;

}

/* Add a service program to the callout list.

   The dispatch routine will be called when a rpc request for this

   program number comes in. */

bool_t

svc_register (SVCXPRT * xprt, rpcprog_t prog, rpcvers_t vers,

	      void (*dispatch) (struct svc_req *, SVCXPRT *),

	      rpcproc_t protocol)

{

  struct svc_callout *prev;

  register struct svc_callout *s;

  if ((s = svc_find (prog, vers, &prev)) != NULL_SVC)

    {

      if (s->sc_dispatch == dispatch)

	goto pmap_it;		/* he is registering another xptr */

      return FALSE;

    }

  s = (struct svc_callout *) mem_alloc (sizeof (struct svc_callout));

  if (s == (struct svc_callout *) 0)

    return FALSE;

  s->sc_prog = prog;

  s->sc_vers = vers;

  s->sc_dispatch = dispatch;

  s->sc_next = svc_head;

  s->sc_mapped = FALSE;

  svc_head = s;

pmap_it:

  /* now register the information with the local binder service */

  if (protocol)

    {

      if (! pmap_set (prog, vers, protocol, xprt->xp_port))

	return FALSE;

      s->sc_mapped = TRUE;

    }

  return TRUE;

}

#ifdef EXPORT_RPC_SYMBOLS

libc_hidden_def (svc_register)

#else

libc_hidden_nolink_sunrpc (svc_register, GLIBC_2_0)

#endif

/* Remove a service program from the callout list. */

void

svc_unregister (rpcprog_t prog, rpcvers_t vers)

{

  struct svc_callout *prev;

  register struct svc_callout *s;

  if ((s = svc_find (prog, vers, &prev)) == NULL_SVC)

    return;

  bool is_mapped = s->sc_mapped;

  if (prev == NULL_SVC)

    svc_head = s->sc_next;

  else

    prev->sc_next = s->sc_next;

  s->sc_next = NULL_SVC;

  mem_free ((char *) s, (u_int) sizeof (struct svc_callout));

  /* now unregister the information with the local binder service */

  if (is_mapped)

    pmap_unset (prog, vers);

}

libc_hidden_nolink_sunrpc (svc_unregister, GLIBC_2_0)

/* ******************* REPLY GENERATION ROUTINES  ************ */

/* Send a reply to an rpc request */

bool_t

svc_sendreply (register SVCXPRT *xprt, xdrproc_t xdr_results,

	       caddr_t xdr_location)

{

  struct rpc_msg rply;

  rply.rm_direction = REPLY;

  rply.rm_reply.rp_stat = MSG_ACCEPTED;

  rply.acpted_rply.ar_verf = xprt->xp_verf;

  rply.acpted_rply.ar_stat = SUCCESS;

  rply.acpted_rply.ar_results.where = xdr_location;

  rply.acpted_rply.ar_results.proc = xdr_results;

  return SVC_REPLY (xprt, &rply);

}

#ifdef EXPORT_RPC_SYMBOLS

libc_hidden_def (svc_sendreply)

#else

libc_hidden_nolink_sunrpc (svc_sendreply, GLIBC_2_0)

#endif

/* No procedure error reply */

void

svcerr_noproc (register SVCXPRT *xprt)

{

  struct rpc_msg rply;

  rply.rm_direction = REPLY;

  rply.rm_reply.rp_stat = MSG_ACCEPTED;

  rply.acpted_rply.ar_verf = xprt->xp_verf;

  rply.acpted_rply.ar_stat = PROC_UNAVAIL;

  SVC_REPLY (xprt, &rply);

}

#ifdef EXPORT_RPC_SYMBOLS

libc_hidden_def (svcerr_noproc)

#else

libc_hidden_nolink_sunrpc (svcerr_noproc, GLIBC_2_0)

#endif

/* Can't decode args error reply */

void

svcerr_decode (register SVCXPRT *xprt)

{

  struct rpc_msg rply;

  rply.rm_direction = REPLY;

  rply.rm_reply.rp_stat = MSG_ACCEPTED;

  rply.acpted_rply.ar_verf = xprt->xp_verf;

  rply.acpted_rply.ar_stat = GARBAGE_ARGS;

  SVC_REPLY (xprt, &rply);

}

#ifdef EXPORT_RPC_SYMBOLS

libc_hidden_def (svcerr_decode)

#else

libc_hidden_nolink_sunrpc (svcerr_decode, GLIBC_2_0)

#endif

/* Some system error */

void

svcerr_systemerr (register SVCXPRT *xprt)

{

  struct rpc_msg rply;

  rply.rm_direction = REPLY;

  rply.rm_reply.rp_stat = MSG_ACCEPTED;

  rply.acpted_rply.ar_verf = xprt->xp_verf;

  rply.acpted_rply.ar_stat = SYSTEM_ERR;

  SVC_REPLY (xprt, &rply);

}

#ifdef EXPORT_RPC_SYMBOLS

libc_hidden_def (svcerr_systemerr)

#else

libc_hidden_nolink_sunrpc (svcerr_systemerr, GLIBC_2_0)

#endif

/* Authentication error reply */

void

svcerr_auth (SVCXPRT *xprt, enum auth_stat why)

{

  struct rpc_msg rply;

  rply.rm_direction = REPLY;

  rply.rm_reply.rp_stat = MSG_DENIED;

  rply.rjcted_rply.rj_stat = AUTH_ERROR;

  rply.rjcted_rply.rj_why = why;

  SVC_REPLY (xprt, &rply);

}

libc_hidden_nolink_sunrpc (svcerr_auth, GLIBC_2_0)

/* Auth too weak error reply */

void

svcerr_weakauth (SVCXPRT *xprt)

{

  svcerr_auth (xprt, AUTH_TOOWEAK);

}

libc_hidden_nolink_sunrpc (svcerr_weakauth, GLIBC_2_0)

/* Program unavailable error reply */

void

svcerr_noprog (register SVCXPRT *xprt)

{

  struct rpc_msg rply;

  rply.rm_direction = REPLY;

  rply.rm_reply.rp_stat = MSG_ACCEPTED;

  rply.acpted_rply.ar_verf = xprt->xp_verf;

  rply.acpted_rply.ar_stat = PROG_UNAVAIL;

  SVC_REPLY (xprt, &rply);

}

libc_hidden_nolink_sunrpc (svcerr_noprog, GLIBC_2_0)

/* Program version mismatch error reply */

void

svcerr_progvers (register SVCXPRT *xprt, rpcvers_t low_vers,

		 rpcvers_t high_vers)

{

  struct rpc_msg rply;

  rply.rm_direction = REPLY;

  rply.rm_reply.rp_stat = MSG_ACCEPTED;

  rply.acpted_rply.ar_verf = xprt->xp_verf;

  rply.acpted_rply.ar_stat = PROG_MISMATCH;

  rply.acpted_rply.ar_vers.low = low_vers;

  rply.acpted_rply.ar_vers.high = high_vers;

  SVC_REPLY (xprt, &rply);

}

libc_hidden_nolink_sunrpc (svcerr_progvers, GLIBC_2_0)

/* ******************* SERVER INPUT STUFF ******************* */

/*

 * Get server side input from some transport.

 *

 * Statement of authentication parameters management:

 * This function owns and manages all authentication parameters, specifically

 * the "raw" parameters (msg.rm_call.cb_cred and msg.rm_call.cb_verf) and

 * the "cooked" credentials (rqst->rq_clntcred).

 * However, this function does not know the structure of the cooked

 * credentials, so it make the following assumptions:

 *   a) the structure is contiguous (no pointers), and

 *   b) the cred structure size does not exceed RQCRED_SIZE bytes.

 * In all events, all three parameters are freed upon exit from this routine.

 * The storage is trivially management on the call stack in user land, but

 * is mallocated in kernel land.

 */

void

svc_getreq (int rdfds)

{

  fd_set readfds;

  FD_ZERO (&readfds);

  readfds.fds_bits[0] = rdfds;

  svc_getreqset (&readfds);

}

libc_hidden_nolink_sunrpc (svc_getreq, GLIBC_2_0)

void

svc_getreqset (fd_set *readfds)

{

  register fd_mask mask;

  register fd_mask *maskp;

  register int setsize;

  register int sock;

  register int bit;

  setsize = _rpc_dtablesize ();

  if (setsize > FD_SETSIZE)

    setsize = FD_SETSIZE;

  maskp = readfds->fds_bits;

  for (sock = 0; sock < setsize; sock += NFDBITS)

    for (mask = *maskp++; (bit = ffsl (mask)); mask ^= (1L << (bit - 1)))

      svc_getreq_common (sock + bit - 1);

}

libc_hidden_nolink_sunrpc (svc_getreqset, GLIBC_2_0)

void

svc_getreq_poll (struct pollfd *pfdp, int pollretval)

{

  if (pollretval == 0)

    return;

  register int fds_found;

  for (int i = fds_found = 0; i < svc_max_pollfd; ++i)

    {

      register struct pollfd *p = &pfdp[i];

      if (p->fd != -1 && p->revents)

	{

	  /* fd has input waiting */

	  if (p->revents & POLLNVAL)

	    xprt_unregister (xports[p->fd]);

	  else

	    svc_getreq_common (p->fd);

	  if (++fds_found >= pollretval)

	    break;

	}

    }

}

#ifdef EXPORT_RPC_SYMBOLS

libc_hidden_def (svc_getreq_poll)

#else

libc_hidden_nolink_sunrpc (svc_getreq_poll, GLIBC_2_2)

#endif

void

svc_getreq_common (const int fd)

{

  enum xprt_stat stat;

  struct rpc_msg msg;

  register SVCXPRT *xprt;

  char cred_area[2 * MAX_AUTH_BYTES + RQCRED_SIZE];

  msg.rm_call.cb_cred.oa_base = cred_area;

  msg.rm_call.cb_verf.oa_base = &(cred_area[MAX_AUTH_BYTES]);

  xprt = xports[fd];

  /* Do we control fd? */

  if (xprt == NULL)

     return;

  /* now receive msgs from xprtprt (support batch calls) */

  do

    {

      if (SVC_RECV (xprt, &msg))

	{

	  /* now find the exported program and call it */

	  struct svc_callout *s;

	  struct svc_req r;

	  enum auth_stat why;

	  rpcvers_t low_vers;

	  rpcvers_t high_vers;

	  int prog_found;

	  r.rq_clntcred = &(cred_area[2 * MAX_AUTH_BYTES]);

	  r.rq_xprt = xprt;

	  r.rq_prog = msg.rm_call.cb_prog;

	  r.rq_vers = msg.rm_call.cb_vers;

	  r.rq_proc = msg.rm_call.cb_proc;

	  r.rq_cred = msg.rm_call.cb_cred;

	  /* first authenticate the message */

	  /* Check for null flavor and bypass these calls if possible */

	  if (msg.rm_call.cb_cred.oa_flavor == AUTH_NULL)

	    {

	      r.rq_xprt->xp_verf.oa_flavor = _null_auth.oa_flavor;

	      r.rq_xprt->xp_verf.oa_length = 0;

	    }

	  else if ((why = _authenticate (&r, &msg)) != AUTH_OK)

	    {

	      svcerr_auth (xprt, why);

	      goto call_done;

	    }

	  /* now match message with a registered service */

	  prog_found = FALSE;

	  low_vers = 0 - 1;

	  high_vers = 0;

	  for (s = svc_head; s != NULL_SVC; s = s->sc_next)

	    {

	      if (s->sc_prog == r.rq_prog)

		{

		  if (s->sc_vers == r.rq_vers)

		    {

		      (*s->sc_dispatch) (&r, xprt);

		      goto call_done;

		    }

		  /* found correct version */

		  prog_found = TRUE;

		  if (s->sc_vers < low_vers)

		    low_vers = s->sc_vers;

		  if (s->sc_vers > high_vers)

		    high_vers = s->sc_vers;

		}

	      /* found correct program */

	    }

	  /* if we got here, the program or version

	     is not served ... */

	  if (prog_found)

	    svcerr_progvers (xprt, low_vers, high_vers);

	  else

	    svcerr_noprog (xprt);

	  /* Fall through to ... */

	}

    call_done:

      if ((stat = SVC_STAT (xprt)) == XPRT_DIED)

	{

	  SVC_DESTROY (xprt);

	  break;

	}

    }

  while (stat == XPRT_MOREREQS);

}

libc_hidden_nolink_sunrpc (svc_getreq_common, GLIBC_2_2)

/* If there are no file descriptors available, then accept will fail.

   We want to delay here so the connection request can be dequeued;

   otherwise we can bounce between polling and accepting, never giving the

   request a chance to dequeue and eating an enormous amount of cpu time

   in svc_run if we're polling on many file descriptors.  */

void

__svc_accept_failed (void)

{

  if (errno == EMFILE)

    {

      struct timespec ts = { .tv_sec = 0, .tv_nsec = 50000000 };

      __nanosleep (&ts, NULL);

    }

}

void

__rpc_thread_svc_cleanup (void)

{

  struct svc_callout *svcp;

  while ((svcp = svc_head) != NULL)

    svc_unregister (svcp->sc_prog, svcp->sc_vers);

}