xref: /src/lib/libc/rpc/clnt_dg.c

/*	$NetBSD: clnt_dg.c,v 1.25.4.1 2013/03/14 22:03:08 riz 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.
 */
/*
 * Copyright (c) 1986-1991 by Sun Microsystems Inc.
 */

/* #ident	"@(#)clnt_dg.c	1.23	94/04/22 SMI" */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)clnt_dg.c 1.19 89/03/16 Copyr 1988 Sun Micro";
#else
__RCSID("$NetBSD: clnt_dg.c,v 1.25.4.1 2013/03/14 22:03:08 riz Exp $");
#endif
#endif

/*
 * Implements a connectionless client side RPC.
 */

#include "namespace.h"
#include "reentrant.h"
#include <sys/poll.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <rpc/rpc.h>
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <err.h>
#include "rpc_internal.h"

#ifdef __weak_alias
__weak_alias(clnt_dg_create,_clnt_dg_create)
#endif

#define	RPC_MAX_BACKOFF		30 /* seconds */


static struct clnt_ops *clnt_dg_ops __P((void));
static bool_t time_not_ok __P((struct timeval *));
static enum clnt_stat clnt_dg_call __P((CLIENT *, rpcproc_t, xdrproc_t,
    const char *, xdrproc_t, caddr_t, struct timeval));
static void clnt_dg_geterr __P((CLIENT *, struct rpc_err *));
static bool_t clnt_dg_freeres __P((CLIENT *, xdrproc_t, caddr_t));
static void clnt_dg_abort __P((CLIENT *));
static bool_t clnt_dg_control __P((CLIENT *, u_int, char *));
static void clnt_dg_destroy __P((CLIENT *));




/*
 *	This machinery implements per-fd locks for MT-safety.  It is not
 *	sufficient to do per-CLIENT handle locks for MT-safety because a
 *	user may create more than one CLIENT handle with the same fd behind
 *	it.  Therfore, we allocate an array of flags (dg_fd_locks), protected
 *	by the clnt_fd_lock mutex, and an array (dg_cv) of condition variables
 *	similarly protected.  Dg_fd_lock[fd] == 1 => a call is activte on some
 *	CLIENT handle created for that fd.
 *	The current implementation holds locks across the entire RPC and reply,
 *	including retransmissions.  Yes, this is silly, and as soon as this
 *	code is proven to work, this should be the first thing fixed.  One step
 *	at a time.
 */
static int	*dg_fd_locks;
#ifdef _REENTRANT
#define __rpc_lock_value __isthreaded;
extern mutex_t clnt_fd_lock;
static cond_t	*dg_cv;
#define	release_fd_lock(fd, mask) {		\
	mutex_lock(&clnt_fd_lock);	\
	dg_fd_locks[fd] = 0;		\
	mutex_unlock(&clnt_fd_lock);	\
	thr_sigsetmask(SIG_SETMASK, &(mask), NULL);	\
	cond_signal(&dg_cv[fd]);	\
}
#else
#define release_fd_lock(fd,mask)
#define __rpc_lock_value 0
#endif

static const char mem_err_clnt_dg[] = "clnt_dg_create: out of memory";

/* VARIABLES PROTECTED BY clnt_fd_lock: dg_fd_locks, dg_cv */

/*
 * Private data kept per client handle
 */
struct cu_data {
	int			cu_fd;		/* connections fd */
	bool_t			cu_closeit;	/* opened by library */
	struct sockaddr_storage	cu_raddr;	/* remote address */
	int			cu_rlen;
	struct timeval		cu_wait;	/* retransmit interval */
	struct timeval		cu_total;	/* total time for the call */
	struct rpc_err		cu_error;
	XDR			cu_outxdrs;
	u_int			cu_xdrpos;
	u_int			cu_sendsz;	/* send size */
	char			*cu_outbuf;
	u_int			cu_recvsz;	/* recv size */
	struct pollfd		cu_pfdp;
	char			cu_inbuf[1];
};

/*
 * Connection less client creation returns with client handle parameters.
 * Default options are set, which the user can change using clnt_control().
 * fd should be open and bound.
 * NB: The rpch->cl_auth is initialized to null authentication.
 * 	Caller may wish to set this something more useful.
 *
 * sendsz and recvsz are the maximum allowable packet sizes that can be
 * sent and received. Normally they are the same, but they can be
 * changed to improve the program efficiency and buffer allocation.
 * If they are 0, use the transport default.
 *
 * If svcaddr is NULL, returns NULL.
 */
CLIENT *
clnt_dg_create(fd, svcaddr, program, version, sendsz, recvsz)
	int fd;				/* open file descriptor */
	const struct netbuf *svcaddr;	/* servers address */
	rpcprog_t program;		/* program number */
	rpcvers_t version;		/* version number */
	u_int sendsz;			/* buffer recv size */
	u_int recvsz;			/* buffer send size */
{
	CLIENT *cl = NULL;		/* client handle */
	struct cu_data *cu = NULL;	/* private data */
	struct rpc_msg call_msg;
#ifdef _REENTRANT
	sigset_t mask;
#endif
	sigset_t newmask;
	struct __rpc_sockinfo si;
	int one = 1;

	sigfillset(&newmask);
	thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
	mutex_lock(&clnt_fd_lock);
	if (dg_fd_locks == NULL) {
#ifdef _REENTRANT
		size_t cv_allocsz;
#endif
		size_t fd_allocsz;
		int dtbsize = __rpc_dtbsize();

		fd_allocsz = dtbsize * sizeof (int);
		dg_fd_locks = mem_alloc(fd_allocsz);
		if (dg_fd_locks == NULL) {
			mutex_unlock(&clnt_fd_lock);
			thr_sigsetmask(SIG_SETMASK, &(mask), NULL);
			goto err1;
		} else
			memset(dg_fd_locks, '\0', fd_allocsz);

#ifdef _REENTRANT
		cv_allocsz = dtbsize * sizeof (cond_t);
		dg_cv = mem_alloc(cv_allocsz);
		if (dg_cv == NULL) {
			mem_free(dg_fd_locks, fd_allocsz);
			dg_fd_locks = NULL;
			mutex_unlock(&clnt_fd_lock);
			thr_sigsetmask(SIG_SETMASK, &(mask), NULL);
			goto err1;
		} else {
			int i;

			for (i = 0; i < dtbsize; i++)
				cond_init(&dg_cv[i], 0, (void *) 0);
		}
#endif
	}

	mutex_unlock(&clnt_fd_lock);
	thr_sigsetmask(SIG_SETMASK, &(mask), NULL);

	if (svcaddr == NULL) {
		rpc_createerr.cf_stat = RPC_UNKNOWNADDR;
		return (NULL);
	}

	if (!__rpc_fd2sockinfo(fd, &si)) {
		rpc_createerr.cf_stat = RPC_TLIERROR;
		rpc_createerr.cf_error.re_errno = 0;
		return (NULL);
	}
	/*
	 * Find the receive and the send size
	 */
	sendsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)sendsz);
	recvsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)recvsz);
	if ((sendsz == 0) || (recvsz == 0)) {
		rpc_createerr.cf_stat = RPC_TLIERROR; /* XXX */
		rpc_createerr.cf_error.re_errno = 0;
		return (NULL);
	}

	if ((cl = mem_alloc(sizeof (CLIENT))) == NULL)
		goto err1;
	/*
	 * Should be multiple of 4 for XDR.
	 */
	sendsz = ((sendsz + 3) / 4) * 4;
	recvsz = ((recvsz + 3) / 4) * 4;
	cu = malloc(sizeof (*cu) + sendsz + recvsz);
	if (cu == NULL)
		goto err1;
	memset(cu, 0, sizeof(*cu));
	(void) memcpy(&cu->cu_raddr, svcaddr->buf, (size_t)svcaddr->len);
	cu->cu_rlen = svcaddr->len;
	cu->cu_outbuf = &cu->cu_inbuf[recvsz];
	/* Other values can also be set through clnt_control() */
	cu->cu_wait.tv_sec = 15;	/* heuristically chosen */
	cu->cu_wait.tv_usec = 0;
	cu->cu_total.tv_sec = -1;
	cu->cu_total.tv_usec = -1;
	cu->cu_sendsz = sendsz;
	cu->cu_recvsz = recvsz;
	call_msg.rm_xid = __RPC_GETXID();
	call_msg.rm_call.cb_prog = program;
	call_msg.rm_call.cb_vers = version;
	xdrmem_create(&(cu->cu_outxdrs), cu->cu_outbuf, sendsz, XDR_ENCODE);
	if (! xdr_callhdr(&(cu->cu_outxdrs), &call_msg)) {
		rpc_createerr.cf_stat = RPC_CANTENCODEARGS;  /* XXX */
		rpc_createerr.cf_error.re_errno = 0;
		goto err2;
	}
	cu->cu_xdrpos = XDR_GETPOS(&(cu->cu_outxdrs));

	/* XXX fvdl - do we still want this? */
#if 0
	(void)bindresvport_sa(fd, (struct sockaddr *)svcaddr->buf);
#endif
	ioctl(fd, FIONBIO, (char *)(void *)&one);

	/*
	 * By default, closeit is always FALSE. It is users responsibility
	 * to do a close on it, else the user may use clnt_control
	 * to let clnt_destroy do it for him/her.
	 */
	cu->cu_closeit = FALSE;
	cu->cu_fd = fd;
	cu->cu_pfdp.fd = cu->cu_fd;
	cu->cu_pfdp.events = POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND;
	cl->cl_ops = clnt_dg_ops();
	cl->cl_private = (caddr_t)(void *)cu;
	cl->cl_auth = authnone_create();
	cl->cl_tp = NULL;
	cl->cl_netid = NULL;
	return (cl);
err1:
	warnx(mem_err_clnt_dg);
	rpc_createerr.cf_stat = RPC_SYSTEMERROR;
	rpc_createerr.cf_error.re_errno = errno;
err2:
	if (cl) {
		mem_free(cl, sizeof (CLIENT));
		if (cu)
			mem_free(cu, sizeof (*cu) + sendsz + recvsz);
	}
	return (NULL);
}

static enum clnt_stat
clnt_dg_call(cl, proc, xargs, argsp, xresults, resultsp, utimeout)
	CLIENT	*cl;			/* client handle */
	rpcproc_t	proc;		/* procedure number */
	xdrproc_t	xargs;		/* xdr routine for args */
	const char *	argsp;		/* pointer to args */
	xdrproc_t	xresults;	/* xdr routine for results */
	caddr_t		resultsp;	/* pointer to results */
	struct timeval	utimeout;	/* seconds to wait before giving up */
{
	struct cu_data *cu;
	XDR *xdrs;
	size_t outlen;
	struct rpc_msg reply_msg;
	XDR reply_xdrs;
	bool_t ok;
	int nrefreshes = 2;		/* number of times to refresh cred */
	struct timeval timeout;
	struct timeval retransmit_time;
	struct timeval next_sendtime, starttime, time_waited, tv;
#ifdef _REENTRANT
	sigset_t mask, *maskp = &mask;
#else
	sigset_t *maskp = NULL;
#endif
	sigset_t newmask;
	ssize_t recvlen = 0;
	struct timespec ts;
	int n;

	_DIAGASSERT(cl != NULL);

	cu = (struct cu_data *)cl->cl_private;

	sigfillset(&newmask);
	thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
	mutex_lock(&clnt_fd_lock);
	while (dg_fd_locks[cu->cu_fd])
		cond_wait(&dg_cv[cu->cu_fd], &clnt_fd_lock);
	dg_fd_locks[cu->cu_fd] = __rpc_lock_value;
	mutex_unlock(&clnt_fd_lock);
	if (cu->cu_total.tv_usec == -1) {
		timeout = utimeout;	/* use supplied timeout */
	} else {
		timeout = cu->cu_total;	/* use default timeout */
	}

	time_waited.tv_sec = 0;
	time_waited.tv_usec = 0;
	retransmit_time = next_sendtime = cu->cu_wait;
	gettimeofday(&starttime, NULL);

call_again:
	xdrs = &(cu->cu_outxdrs);
	xdrs->x_op = XDR_ENCODE;
	XDR_SETPOS(xdrs, cu->cu_xdrpos);
	/*
	 * the transaction is the first thing in the out buffer
	 */
	(*(u_int32_t *)(void *)(cu->cu_outbuf))++;
	if ((! XDR_PUTINT32(xdrs, (int32_t *)&proc)) ||
	    (! AUTH_MARSHALL(cl->cl_auth, xdrs)) ||
	    (! (*xargs)(xdrs, __UNCONST(argsp)))) {
		cu->cu_error.re_status = RPC_CANTENCODEARGS;
		goto out;
	}
	outlen = (size_t)XDR_GETPOS(xdrs);

send_again:
	if ((size_t)sendto(cu->cu_fd, cu->cu_outbuf, outlen, 0,
	    (struct sockaddr *)(void *)&cu->cu_raddr, (socklen_t)cu->cu_rlen)
	    != outlen) {
		cu->cu_error.re_errno = errno;
		cu->cu_error.re_status = RPC_CANTSEND;
		goto out;
	}

	/*
	 * Hack to provide rpc-based message passing
	 */
	if (timeout.tv_sec == 0 && timeout.tv_usec == 0) {
		cu->cu_error.re_status = RPC_TIMEDOUT;
		goto out;
	}
	/*
	 * sub-optimal code appears here because we have
	 * some clock time to spare while the packets are in flight.
	 * (We assume that this is actually only executed once.)
	 */
	reply_msg.acpted_rply.ar_verf = _null_auth;
	reply_msg.acpted_rply.ar_results.where = resultsp;
	reply_msg.acpted_rply.ar_results.proc = xresults;


	for (;;) {
		/* Decide how long to wait. */
		if (timercmp(&next_sendtime, &timeout, <))
			timersub(&next_sendtime, &time_waited, &tv);
		else
			timersub(&timeout, &time_waited, &tv);
		if (tv.tv_sec < 0 || tv.tv_usec < 0)
			tv.tv_sec = tv.tv_usec = 0;
		TIMEVAL_TO_TIMESPEC(&tv, &ts);

		n = pollts(&cu->cu_pfdp, 1, &ts, maskp);
		if (n == 1) {
			/* We have some data now */
			do {
				recvlen = recvfrom(cu->cu_fd, cu->cu_inbuf,
				    cu->cu_recvsz, 0, NULL, NULL);
			} while (recvlen < 0 && errno == EINTR);

			if (recvlen < 0 && errno != EWOULDBLOCK) {
				cu->cu_error.re_errno = errno;
				cu->cu_error.re_status = RPC_CANTRECV;
				goto out;
			}
			if (recvlen >= (ssize_t)sizeof(uint32_t)) {
				if (memcmp(cu->cu_inbuf, cu->cu_outbuf,
				    sizeof(uint32_t)) == 0)
					/* Assume we have the proper reply. */
					break;
			}
		}
		if (n == -1) {
			cu->cu_error.re_errno = errno;
			cu->cu_error.re_status = RPC_CANTRECV;
			goto out;
		}

		gettimeofday(&tv, NULL);
		timersub(&tv, &starttime, &time_waited);

		/* Check for timeout. */
		if (timercmp(&time_waited, &timeout, >)) {
			cu->cu_error.re_status = RPC_TIMEDOUT;
			goto out;
		}

		/* Retransmit if necessary. */
		if (timercmp(&time_waited, &next_sendtime, >)) {
			/* update retransmit_time */
			if (retransmit_time.tv_sec < RPC_MAX_BACKOFF)
				timeradd(&retransmit_time, &retransmit_time,
				    &retransmit_time);
			timeradd(&next_sendtime, &retransmit_time,
			    &next_sendtime);
			goto send_again;
		}
	}

	/*
	 * now decode and validate the response
	 */

	xdrmem_create(&reply_xdrs, cu->cu_inbuf, (u_int)recvlen, XDR_DECODE);
	ok = xdr_replymsg(&reply_xdrs, &reply_msg);
	/* XDR_DESTROY(&reply_xdrs);	save a few cycles on noop destroy */
	if (ok) {
		if ((reply_msg.rm_reply.rp_stat == MSG_ACCEPTED) &&
			(reply_msg.acpted_rply.ar_stat == SUCCESS))
			cu->cu_error.re_status = RPC_SUCCESS;
		else
			_seterr_reply(&reply_msg, &(cu->cu_error));

		if (cu->cu_error.re_status == RPC_SUCCESS) {
			if (! AUTH_VALIDATE(cl->cl_auth,
					    &reply_msg.acpted_rply.ar_verf)) {
				cu->cu_error.re_status = RPC_AUTHERROR;
				cu->cu_error.re_why = AUTH_INVALIDRESP;
			}
			if (reply_msg.acpted_rply.ar_verf.oa_base != NULL) {
				xdrs->x_op = XDR_FREE;
				(void) xdr_opaque_auth(xdrs,
					&(reply_msg.acpted_rply.ar_verf));
			}
		}		/* end successful completion */
		/*
		 * If unsuccesful AND error is an authentication error
		 * then refresh credentials and try again, else break
		 */
		else if (cu->cu_error.re_status == RPC_AUTHERROR)
			/* maybe our credentials need to be refreshed ... */
			if (nrefreshes > 0 && AUTH_REFRESH(cl->cl_auth)) {
				nrefreshes--;
				goto call_again;
			}
		/* end of unsuccessful completion */
	}	/* end of valid reply message */
	else {
		cu->cu_error.re_status = RPC_CANTDECODERES;

	}
out:
	release_fd_lock(cu->cu_fd, mask);
	return (cu->cu_error.re_status);
}

static void
clnt_dg_geterr(cl, errp)
	CLIENT *cl;
	struct rpc_err *errp;
{
	struct cu_data *cu;

	_DIAGASSERT(cl != NULL);
	_DIAGASSERT(errp != NULL);

	cu = (struct cu_data *)cl->cl_private;
	*errp = cu->cu_error;
}

static bool_t
clnt_dg_freeres(cl, xdr_res, res_ptr)
	CLIENT *cl;
	xdrproc_t xdr_res;
	caddr_t res_ptr;
{
	struct cu_data *cu;
	XDR *xdrs;
	bool_t dummy;
#ifdef _REENTRANT
	sigset_t mask;
#endif
	sigset_t newmask;

	_DIAGASSERT(cl != NULL);
	cu = (struct cu_data *)cl->cl_private;
	xdrs = &(cu->cu_outxdrs);

	sigfillset(&newmask);
	thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
	mutex_lock(&clnt_fd_lock);
	while (dg_fd_locks[cu->cu_fd])
		cond_wait(&dg_cv[cu->cu_fd], &clnt_fd_lock);
	xdrs->x_op = XDR_FREE;
	dummy = (*xdr_res)(xdrs, res_ptr);
	mutex_unlock(&clnt_fd_lock);
	thr_sigsetmask(SIG_SETMASK, &mask, NULL);
	cond_signal(&dg_cv[cu->cu_fd]);
	return (dummy);
}

/*ARGSUSED*/
static void
clnt_dg_abort(h)
	CLIENT *h;
{
}

static bool_t
clnt_dg_control(cl, request, info)
	CLIENT *cl;
	u_int request;
	char *info;
{
	struct cu_data *cu;
	struct netbuf *addr;
#ifdef _REENTRANT
	sigset_t mask;
#endif
	sigset_t newmask;

	_DIAGASSERT(cl != NULL);
	/* info is handled below */

	cu = (struct cu_data *)cl->cl_private;

	sigfillset(&newmask);
	thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
	mutex_lock(&clnt_fd_lock);
	while (dg_fd_locks[cu->cu_fd])
		cond_wait(&dg_cv[cu->cu_fd], &clnt_fd_lock);
	dg_fd_locks[cu->cu_fd] = __rpc_lock_value;
	mutex_unlock(&clnt_fd_lock);
	switch (request) {
	case CLSET_FD_CLOSE:
		cu->cu_closeit = TRUE;
		release_fd_lock(cu->cu_fd, mask);
		return (TRUE);
	case CLSET_FD_NCLOSE:
		cu->cu_closeit = FALSE;
		release_fd_lock(cu->cu_fd, mask);
		return (TRUE);
	}

	/* for other requests which use info */
	if (info == NULL) {
		release_fd_lock(cu->cu_fd, mask);
		return (FALSE);
	}
	switch (request) {
	case CLSET_TIMEOUT:
		if (time_not_ok((struct timeval *)(void *)info)) {
			release_fd_lock(cu->cu_fd, mask);
			return (FALSE);
		}
		cu->cu_total = *(struct timeval *)(void *)info;
		break;
	case CLGET_TIMEOUT:
		*(struct timeval *)(void *)info = cu->cu_total;
		break;
	case CLGET_SERVER_ADDR:		/* Give him the fd address */
		/* Now obsolete. Only for backward compatibility */
		(void) memcpy(info, &cu->cu_raddr, (size_t)cu->cu_rlen);
		break;
	case CLSET_RETRY_TIMEOUT:
		if (time_not_ok((struct timeval *)(void *)info)) {
			release_fd_lock(cu->cu_fd, mask);
			return (FALSE);
		}
		cu->cu_wait = *(struct timeval *)(void *)info;
		break;
	case CLGET_RETRY_TIMEOUT:
		*(struct timeval *)(void *)info = cu->cu_wait;
		break;
	case CLGET_FD:
		*(int *)(void *)info = cu->cu_fd;
		break;
	case CLGET_SVC_ADDR:
		addr = (struct netbuf *)(void *)info;
		addr->buf = &cu->cu_raddr;
		addr->len = cu->cu_rlen;
		addr->maxlen = sizeof cu->cu_raddr;
		break;
	case CLSET_SVC_ADDR:		/* set to new address */
		addr = (struct netbuf *)(void *)info;
		if (addr->len < sizeof cu->cu_raddr) {
			release_fd_lock(cu->cu_fd, mask);
			return (FALSE);
		}
		(void) memcpy(&cu->cu_raddr, addr->buf, (size_t)addr->len);
		cu->cu_rlen = addr->len;
		break;
	case CLGET_XID:
		/*
		 * use the knowledge that xid is the
		 * first element in the call structure *.
		 * This will get the xid of the PREVIOUS call
		 */
		*(u_int32_t *)(void *)info =
		    ntohl(*(u_int32_t *)(void *)cu->cu_outbuf);
		break;

	case CLSET_XID:
		/* This will set the xid of the NEXT call */
		*(u_int32_t *)(void *)cu->cu_outbuf =
		    htonl(*(u_int32_t *)(void *)info - 1);
		/* decrement by 1 as clnt_dg_call() increments once */
		break;

	case CLGET_VERS:
		/*
		 * This RELIES on the information that, in the call body,
		 * the version number field is the fifth field from the
		 * begining of the RPC header. MUST be changed if the
		 * call_struct is changed
		 */
		*(u_int32_t *)(void *)info =
		    ntohl(*(u_int32_t *)(void *)(cu->cu_outbuf +
		    4 * BYTES_PER_XDR_UNIT));
		break;

	case CLSET_VERS:
		*(u_int32_t *)(void *)(cu->cu_outbuf + 4 * BYTES_PER_XDR_UNIT)
			= htonl(*(u_int32_t *)(void *)info);
		break;

	case CLGET_PROG:
		/*
		 * This RELIES on the information that, in the call body,
		 * the program number field is the fourth field from the
		 * begining of the RPC header. MUST be changed if the
		 * call_struct is changed
		 */
		*(u_int32_t *)(void *)info =
		    ntohl(*(u_int32_t *)(void *)(cu->cu_outbuf +
		    3 * BYTES_PER_XDR_UNIT));
		break;

	case CLSET_PROG:
		*(u_int32_t *)(void *)(cu->cu_outbuf + 3 * BYTES_PER_XDR_UNIT)
			= htonl(*(u_int32_t *)(void *)info);
		break;

	default:
		release_fd_lock(cu->cu_fd, mask);
		return (FALSE);
	}
	release_fd_lock(cu->cu_fd, mask);
	return (TRUE);
}

static void
clnt_dg_destroy(cl)
	CLIENT *cl;
{
	struct cu_data *cu;
	int cu_fd;
#ifdef _REENTRANT
	sigset_t mask;
#endif
	sigset_t newmask;

	_DIAGASSERT(cl != NULL);

	cu = (struct cu_data *)cl->cl_private;
	cu_fd = cu->cu_fd;

	sigfillset(&newmask);
	thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
	mutex_lock(&clnt_fd_lock);
	while (dg_fd_locks[cu_fd])
		cond_wait(&dg_cv[cu_fd], &clnt_fd_lock);
	if (cu->cu_closeit)
		(void) close(cu_fd);
	XDR_DESTROY(&(cu->cu_outxdrs));
	mem_free(cu, (sizeof (*cu) + cu->cu_sendsz + cu->cu_recvsz));
	if (cl->cl_netid && cl->cl_netid[0])
		mem_free(cl->cl_netid, strlen(cl->cl_netid) +1);
	if (cl->cl_tp && cl->cl_tp[0])
		mem_free(cl->cl_tp, strlen(cl->cl_tp) +1);
	mem_free(cl, sizeof (CLIENT));
	mutex_unlock(&clnt_fd_lock);
	thr_sigsetmask(SIG_SETMASK, &mask, NULL);
	cond_signal(&dg_cv[cu_fd]);
}

static struct clnt_ops *
clnt_dg_ops()
{
	static struct clnt_ops ops;
#ifdef _REENTRANT
	extern mutex_t	ops_lock;
	sigset_t mask;
#endif
	sigset_t newmask;

/* VARIABLES PROTECTED BY ops_lock: ops */

	sigfillset(&newmask);
	thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
	mutex_lock(&ops_lock);
	if (ops.cl_call == NULL) {
		ops.cl_call = clnt_dg_call;
		ops.cl_abort = clnt_dg_abort;
		ops.cl_geterr = clnt_dg_geterr;
		ops.cl_freeres = clnt_dg_freeres;
		ops.cl_destroy = clnt_dg_destroy;
		ops.cl_control = clnt_dg_control;
	}
	mutex_unlock(&ops_lock);
	thr_sigsetmask(SIG_SETMASK, &mask, NULL);
	return (&ops);
}

/*
 * Make sure that the time is not garbage.  -1 value is allowed.
 */
static bool_t
time_not_ok(t)
	struct timeval *t;
{

	_DIAGASSERT(t != NULL);

	return (t->tv_sec < -1 || t->tv_sec > 100000000 ||
		t->tv_usec < -1 || t->tv_usec > 1000000);
}