NetBSD/lib/libc/rpc/svc.c

/*	$NetBSD: svc.c,v 1.40 2021/08/21 23:00:30 andvar Exp $	*/

/*
 * 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 <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint) 
#if 0
static char *sccsid = "@(#)svc.c 1.44 88/02/08 Copyr 1984 Sun Micro";
static char *sccsid = "@(#)svc.c	2.4 88/08/11 4.0 RPCSRC";
#else
__RCSID("$NetBSD: svc.c,v 1.40 2021/08/21 23:00:30 andvar Exp $");
#endif
#endif

/*
 * 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) 1984, Sun Microsystems, Inc.
 */

#include "namespace.h"
#include "reentrant.h"
#include <sys/types.h>
#include <sys/poll.h>
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>

#include <rpc/rpc.h>
#ifdef PORTMAP
#include <rpc/pmap_clnt.h>
#endif

#include "svc_fdset.h"
#include "rpc_internal.h"

#ifdef __weak_alias
__weak_alias(svc_getreq,_svc_getreq)
__weak_alias(svc_getreqset,_svc_getreqset)
__weak_alias(svc_getreq_common,_svc_getreq_common)
__weak_alias(svc_register,_svc_register)
__weak_alias(svc_reg,_svc_reg)
__weak_alias(svc_unreg,_svc_unreg)
__weak_alias(svc_sendreply,_svc_sendreply)
__weak_alias(svc_unregister,_svc_unregister)
__weak_alias(svcerr_auth,_svcerr_auth)
__weak_alias(svcerr_decode,_svcerr_decode)
__weak_alias(svcerr_noproc,_svcerr_noproc)
__weak_alias(svcerr_noprog,_svcerr_noprog)
__weak_alias(svcerr_progvers,_svcerr_progvers)
__weak_alias(svcerr_systemerr,_svcerr_systemerr)
__weak_alias(svcerr_weakauth,_svcerr_weakauth)
__weak_alias(xprt_register,_xprt_register)
__weak_alias(xprt_unregister,_xprt_unregister)
__weak_alias(rpc_control,_rpc_control)
#endif

/* __svc_xports[-1] is reserved for raw */
SVCXPRT **__svc_xports;
int __svc_maxxports;
int __svc_maxrec;

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

#define SVC_VERSQUIET 0x0001		/* keep quiet about vers mismatch */
#define version_keepquiet(xp) ((u_long)(xp)->xp_p3 & SVC_VERSQUIET)

#define max(a, b) (a > b ? a : b)

/*
 * The services list
 * Each entry represents a set of procedures (an rpc program).
 * The dispatch routine takes request structs and runs the
 * appropriate procedure.
 */
static struct svc_callout {
	struct svc_callout *sc_next;
	rpcprog_t	    sc_prog;
	rpcvers_t	    sc_vers;
	char		   *sc_netid;
	void		    (*sc_dispatch)(struct svc_req *, SVCXPRT *);
} *svc_head;

#ifdef _REENTRANT
extern rwlock_t svc_lock;
extern rwlock_t svc_fd_lock;
#endif

static struct svc_callout *svc_find(rpcprog_t, rpcvers_t,
					 struct svc_callout **, char *);
static void __xprt_do_unregister(SVCXPRT *xprt, bool_t dolock);

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

static bool_t
xprt_alloc(int sock)
{
	int oldmaxxports, newmaxxports;
	SVCXPRT **oldxports, **newxports;

	if (++sock < 0)
		return FALSE;

	newmaxxports = svc_fdset_getsize(sock);
	if (newmaxxports == -1)
		return FALSE;

	if (__svc_xports != NULL && newmaxxports < __svc_maxxports)
		return TRUE;

	oldxports = __svc_xports;
	oldmaxxports = __svc_maxxports;
	if (oldxports != NULL) {
		/* revert saving [-1] slot */
		--oldxports;
		++oldmaxxports;
	}

	/* reserve an extra slot for [-1] */
	newmaxxports++;
	newxports = realloc(oldxports, newmaxxports * sizeof(SVCXPRT *));
	if (newxports == NULL) {
		warn("%s: out of memory", __func__);
		return FALSE;
	}

	memset(&newxports[oldmaxxports], 0,
	    (newmaxxports - oldmaxxports) * sizeof(SVCXPRT *));

	/* save one slot for [-1] */
	__svc_xports = newxports + 1;
	__svc_maxxports = newmaxxports - 1;

	return TRUE;
}

/*
 * Activate a transport handle.
 */
bool_t
xprt_register(SVCXPRT *xprt)
{
	int sock;

	_DIAGASSERT(xprt != NULL);

	rwlock_wrlock(&svc_fd_lock);
	sock = xprt->xp_fd;

	if (!xprt_alloc(sock))
		goto out;

	__svc_xports[sock] = xprt;
	if (sock != -1) {
		if (svc_fdset_set(sock) == -1)
			return FALSE;
	}
	rwlock_unlock(&svc_fd_lock);
	return (TRUE);

out:
	rwlock_unlock(&svc_fd_lock);
	return (FALSE);
}

void
xprt_unregister(SVCXPRT *xprt)
{
	__xprt_do_unregister(xprt, TRUE);
}

void
__xprt_unregister_unlocked(SVCXPRT *xprt)
{
	__xprt_do_unregister(xprt, FALSE);
}

/*
 * De-activate a transport handle. 
 */
static void
__xprt_do_unregister(SVCXPRT *xprt, bool_t dolock)
{ 
	int sock, *fdmax;

	_DIAGASSERT(xprt != NULL);

	if (dolock)
		rwlock_wrlock(&svc_fd_lock);

	sock = xprt->xp_fd;
	if (sock >= __svc_maxxports || __svc_xports[sock] != xprt)
		goto out;

	__svc_xports[sock] = NULL;
	if (sock == -1)
		goto out;
	fdmax = svc_fdset_getmax();
	if (fdmax == NULL || sock < *fdmax)
		goto clr;

	for ((*fdmax)--; *fdmax >= 0; (*fdmax)--)
		if (__svc_xports[*fdmax])
			break;
clr:
	svc_fdset_clr(sock);
out:
	if (dolock)
		rwlock_unlock(&svc_fd_lock);
}

/*
 * 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_reg(SVCXPRT *xprt, const rpcprog_t prog, const rpcvers_t vers,
	void (*dispatch)(struct svc_req *, SVCXPRT *),
	const struct netconfig *nconf)
{
	bool_t dummy;
	struct svc_callout *prev;
	struct svc_callout *s;
	struct netconfig *tnconf;
	char *netid = NULL;
	int flag = 0;

	_DIAGASSERT(xprt != NULL);
	/* XXX: dispatch may be NULL ??? */

/* VARIABLES PROTECTED BY svc_lock: s, prev, svc_head */

	if (xprt->xp_netid) {
		netid = strdup(xprt->xp_netid);
		flag = 1;
	} else if (nconf && nconf->nc_netid) {
		netid = strdup(nconf->nc_netid);
		flag = 1;
	} else if ((tnconf = __rpcgettp(xprt->xp_fd)) != NULL) {
		netid = strdup(tnconf->nc_netid);
		flag = 1;
		freenetconfigent(tnconf);
	} /* must have been created with svc_raw_create */
	if ((netid == NULL) && (flag == 1)) {
		return (FALSE);
	}

	rwlock_wrlock(&svc_lock);
	if ((s = svc_find(prog, vers, &prev, netid)) != NULL) {
		if (netid)
			free(netid);
		if (s->sc_dispatch == dispatch)
			goto rpcb_it; /* he is registering another xptr */
		rwlock_unlock(&svc_lock);
		return (FALSE);
	}
	s = mem_alloc(sizeof (struct svc_callout));
	if (s == NULL) {
		if (netid)
			free(netid);
		rwlock_unlock(&svc_lock);
		return (FALSE);
	}

	if ((xprt->xp_netid == NULL) && (flag == 1) && netid)
		if ((((SVCXPRT *) xprt)->xp_netid = strdup(netid)) == NULL) {
			warn("svc_reg");
			mem_free(s, sizeof(struct svc_callout));
			rwlock_unlock(&svc_lock);
			return FALSE;
		}

	s->sc_prog = prog;
	s->sc_vers = vers;
	s->sc_dispatch = dispatch;
	s->sc_netid = netid;
	s->sc_next = svc_head;
	svc_head = s;

rpcb_it:
	rwlock_unlock(&svc_lock);
	/* now register the information with the local binder service */
	if (nconf) {
		dummy = rpcb_set(prog, vers, __UNCONST(nconf),
		&((SVCXPRT *) xprt)->xp_ltaddr);
		return (dummy);
	}
	return (TRUE);
}

/*
 * Remove a service program from the callout list.
 */
void
svc_unreg(const rpcprog_t prog, const rpcvers_t vers)
{
	struct svc_callout *prev;
	struct svc_callout *s;

	/* unregister the information anyway */
	(void) rpcb_unset(prog, vers, NULL);
	rwlock_wrlock(&svc_lock);
	while ((s = svc_find(prog, vers, &prev, NULL)) != NULL) {
		if (prev == NULL) {
			svc_head = s->sc_next;
		} else {
			prev->sc_next = s->sc_next;
		}
		s->sc_next = NULL;
		if (s->sc_netid)
			mem_free(s->sc_netid, sizeof (s->sc_netid) + 1);
		mem_free(s, sizeof (struct svc_callout));
	}
	rwlock_unlock(&svc_lock);
}

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

#ifdef PORTMAP
/*
 * 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, u_long prog, u_long vers,
	void (*dispatch)(struct svc_req *, SVCXPRT *), int protocol)
{
	struct svc_callout *prev;
	struct svc_callout *s;

	_DIAGASSERT(xprt != NULL);
	_DIAGASSERT(dispatch != NULL);

	if ((s = svc_find((rpcprog_t)prog, (rpcvers_t)vers, &prev, NULL)) !=
	    NULL) {
		if (s->sc_dispatch == dispatch)
			goto pmap_it;  /* he is registering another xptr */
		return (FALSE);
	}
	s = mem_alloc(sizeof(struct svc_callout));
	if (s == NULL) {
		return (FALSE);
	}
	s->sc_prog = (rpcprog_t)prog;
	s->sc_vers = (rpcvers_t)vers;
	s->sc_dispatch = dispatch;
	s->sc_next = svc_head;
	svc_head = s;
pmap_it:
	/* now register the information with the local binder service */
	if (protocol) {
		return (pmap_set(prog, vers, protocol, xprt->xp_port));
	}
	return (TRUE);
}

/*
 * Remove a service program from the callout list.
 */
void
svc_unregister(u_long prog, u_long vers)
{
	struct svc_callout *prev;
	struct svc_callout *s;

	if ((s = svc_find((rpcprog_t)prog, (rpcvers_t)vers, &prev, NULL)) ==
	    NULL)
		return;
	if (prev == NULL) {
		svc_head = s->sc_next;
	} else {
		prev->sc_next = s->sc_next;
	}
	s->sc_next = NULL;
	mem_free(s, sizeof(struct svc_callout));
	/* now unregister the information with the local binder service */
	(void)pmap_unset(prog, vers);
}
#endif /* PORTMAP */

/*
 * 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, char *netid)
{
	struct svc_callout *s, *p;

	_DIAGASSERT(prev != NULL);
	/* netid is handled below */

	p = NULL;
	for (s = svc_head; s != NULL; s = s->sc_next) {
		if (((s->sc_prog == prog) && (s->sc_vers == vers)) &&
		    ((netid == NULL) || (s->sc_netid == NULL) ||
		    (strcmp(netid, s->sc_netid) == 0)))
			break;
		p = s;
	}
	*prev = p;
	return (s);
}

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

/*
 * Send a reply to an rpc request
 */
bool_t
svc_sendreply(SVCXPRT *xprt, xdrproc_t xdr_results, const char *xdr_location)
{
	struct rpc_msg rply; 

	_DIAGASSERT(xprt != NULL);

	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)); 
}

/*
 * No procedure error reply
 */
void
svcerr_noproc(SVCXPRT *xprt)
{
	struct rpc_msg rply;

	_DIAGASSERT(xprt != NULL);

	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);
}

/*
 * Can't decode args error reply
 */
void
svcerr_decode(SVCXPRT *xprt)
{
	struct rpc_msg rply; 

	_DIAGASSERT(xprt != NULL);

	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); 
}

/*
 * Some system error
 */
void
svcerr_systemerr(SVCXPRT *xprt)
{
	struct rpc_msg rply; 

	_DIAGASSERT(xprt != NULL);

	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); 
}

#if 0
/*
 * Tell RPC package to not complain about version errors to the client.	 This
 * is useful when revving broadcast protocols that sit on a fixed address.
 * There is really one (or should be only one) example of this kind of
 * protocol: the portmapper (or rpc binder).
 */
void
__svc_versquiet_on(SVCXPRT *xprt)
{
	u_long	tmp;

	_DIAGASSERT(xprt != NULL);

	tmp = ((u_long) xprt->xp_p3) | SVC_VERSQUIET;
	xprt->xp_p3 = (caddr_t) tmp;
}

void
__svc_versquiet_off(SVCXPRT *xprt)
{
	u_long	tmp;

	_DIAGASSERT(xprt != NULL);

	tmp = ((u_long) xprt->xp_p3) & ~SVC_VERSQUIET;
	xprt->xp_p3 = (caddr_t) tmp;
}

void
svc_versquiet(SVCXPRT *xprt)
{
	__svc_versquiet_on(xprt);
}

int
__svc_versquiet_get(SVCXPRT *xprt)
{

	_DIAGASSERT(xprt != NULL);

	return ((int) xprt->xp_p3) & SVC_VERSQUIET;
}
#endif

/*
 * Authentication error reply
 */
void
svcerr_auth(SVCXPRT *xprt, enum auth_stat why)
{
	struct rpc_msg rply;

	_DIAGASSERT(xprt != NULL);

	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);
}

/*
 * Auth too weak error reply
 */
void
svcerr_weakauth(SVCXPRT *xprt)
{

	_DIAGASSERT(xprt != NULL);

	svcerr_auth(xprt, AUTH_TOOWEAK);
}

/*
 * Program unavailable error reply
 */
void 
svcerr_noprog(SVCXPRT *xprt)
{
	struct rpc_msg rply;  

	_DIAGASSERT(xprt != NULL);

	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);
}

/*
 * Program version mismatch error reply
 */
void  
svcerr_progvers(SVCXPRT *xprt, rpcvers_t low_vers, rpcvers_t high_vers)
{
	struct rpc_msg rply;

	_DIAGASSERT(xprt != NULL);

	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 = (u_int32_t)low_vers;
	rply.acpted_rply.ar_vers.high = (u_int32_t)high_vers;
	SVC_REPLY(xprt, &rply);
}

/* ******************* 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 = svc_fdset_copy(NULL);
	if (readfds == NULL)
		return;

	readfds->fds_bits[0] = (unsigned int)rdfds;
	svc_getreqset(readfds);
	free(readfds);
}

void
svc_getreqset2(fd_set *readfds, int maxsize)
{
	uint32_t mask, *maskp;
	int sock, bit, fd;

	_DIAGASSERT(readfds != NULL);

	maskp = readfds->fds_bits;
	for (sock = 0; sock < maxsize; sock += NFDBITS) {
	    for (mask = *maskp++; (bit = ffs((int)mask)) != 0;
		mask ^= (1 << (bit - 1))) {
		/* sock has input waiting */
		fd = sock + bit - 1;
		svc_getreq_common(fd);
	    }
	}
}

void
svc_getreqset(fd_set *readfds)
{
	svc_getreqset2(readfds, FD_SETSIZE);
}

void
svc_getreq_common(int fd)
{
	SVCXPRT *xprt;
	struct svc_req r;
	struct rpc_msg msg;
	int prog_found;
	rpcvers_t low_vers;
	rpcvers_t high_vers;
	enum xprt_stat stat;
	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]);
	r.rq_clntcred = &(cred_area[2*MAX_AUTH_BYTES]);

	rwlock_rdlock(&svc_fd_lock);
	xprt = __svc_xports[fd];
	rwlock_unlock(&svc_fd_lock);
	if (xprt == NULL)
		/* But do we control sock? */
		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;
			enum auth_stat why;

			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 */
			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 = (rpcvers_t) -1L;
			high_vers = (rpcvers_t) 0L;
			for (s = svc_head; s != NULL; 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 ... */
		}
		/*
		 * Check if the xprt has been disconnected in a
		 * recursive call in the service dispatch routine.
		 * If so, then break.
		 */
		rwlock_rdlock(&svc_fd_lock);
		if (xprt != __svc_xports[fd]) {
			rwlock_unlock(&svc_fd_lock);
			break;
		}
		rwlock_unlock(&svc_fd_lock);
call_done:
		if ((stat = SVC_STAT(xprt)) == XPRT_DIED){
			SVC_DESTROY(xprt);
			break;
		}
	} while (stat == XPRT_MOREREQS);
}


void
svc_getreq_poll(struct pollfd *pfdp, int pollretval)
{
	int i;
	int fds_found;

	_DIAGASSERT(pfdp != NULL);

	for (i = fds_found = 0; fds_found < pollretval; i++) {
		struct pollfd *p = &pfdp[i];

		if (p->revents) {
			/* fd has input waiting */
			fds_found++;
			/*
			 *	We assume that this function is only called
			 *	via someone select()ing from svc_fdset or
			 *	pollts()ing from svc_pollset[].  Thus it's safe
			 *	to handle the POLLNVAL event by simply turning
			 *	the corresponding bit off in the fdset.  The
			 *	svc_pollset[] array is derived from svc_fdset
			 *	and so will also be updated eventually.
			 *
			 *	XXX Should we do an xprt_unregister() instead?
			 */
			if (p->revents & POLLNVAL) {
				rwlock_wrlock(&svc_fd_lock);
				svc_fdset_clr(p->fd);
				rwlock_unlock(&svc_fd_lock);
			} else
				svc_getreq_common(p->fd);
		}
	}
}

bool_t
rpc_control(int what, void *arg)
{
	int val;

	switch (what) {
	case RPC_SVC_CONNMAXREC_SET:
		val = *(int *)arg;
		if (val <= 0)
			return FALSE;
		__svc_maxrec = val;
		return TRUE;
	case RPC_SVC_CONNMAXREC_GET:
		*(int *)arg = __svc_maxrec;
		return TRUE;
	default:
		break;
	}
	return FALSE;
}