libnsl/nsl/t_look.c

	t_look.c revision e8031f0a8ed0e45c6d8847c5e09424e66fd34a4b
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */

/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "mt.h"
#include <errno.h>
#include <unistd.h>
#include <sys/stream.h>
#include <stropts.h>
#define _SUN_TPI_VERSION 2
#include <sys/tihdr.h>
#include <sys/timod.h>
#include <xti.h>
#include <assert.h>
#include "tx.h"

int
_tx_look(int fd, int api_semantics)
{
    int state;
    int sv_errno;
    int do_expinline_peek;   /* unusual XTI specific processing */
    struct _ti_user *tiptr;

    if ((tiptr = _t_checkfd(fd, 0, api_semantics)) == NULL)
        return (-1);
    sig_mutex_lock(&tiptr->ti_lock);

    if (_T_IS_XTI(api_semantics))
        do_expinline_peek = 1;
    else
        do_expinline_peek = 0;
    state = _t_look_locked(fd, tiptr, do_expinline_peek, api_semantics);

    sv_errno = errno;

    sig_mutex_unlock(&tiptr->ti_lock);
    errno = sv_errno;
    return (state);
}

/*
 * _t_look_locked() assumes tiptr->ti_lock lock is already held and signals
 * already blocked in MT case.
 * Intended for use by other TLI routines only.
 */
int
_t_look_locked(
    int fd,
    struct _ti_user *tiptr,
    int do_expinline_peek,
    int api_semantics
)
{
    struct strpeek strpeek;
    int retval;
    union T_primitives *pptr;
    t_scalar_t type;
    t_scalar_t ctltype;

    assert(MUTEX_HELD(&tiptr->ti_lock));

#ifdef notyet
    if (_T_IS_XTI(api_semantics)) {
        /*
         * XTI requires the strange T_GODATA and T_GOEXDATA
         * events which are almost brain-damaged but thankfully
         * not tested. Anyone feeling the need for those should
         * consider the need for using non-blocking endpoint.
         * Probably introduced at the behest of some weird-os
         * vendor which did not understand the non-blocking endpoint
         * option.
         * We choose not to implment these mis-features.
         * Here is the plan-of-action (POA)if we are ever forced
         * to implement these.
         * - When returning TFLOW set state to indicate if it was
         *   a normal or expedited data send attempt.
         * - In routines that set TFLOW, clear the above set state
         *   on each entry/reentry
         * - In this routine, if that state flag is set,
         * do a I_CANPUT on appropriate band to to see if it
         * is writeable. If that indicates that the band is
         * writeable, return T_GODATA or T_GOEXDATA event.
         *
         * Actions are also influenced by whether T_EXDATA_REQ stays
         * band 1 or goes to band 0 if EXPINLINE is set
         *
         * We will also need to sort out if "write side" events
         * (such as T_GODATA/T_GOEXDATA) take precedence over
         * all other events (all read side) or not.
         */
    }
#endif /* notyet */

    strpeek.ctlbuf.maxlen = (int)sizeof (ctltype);
    strpeek.ctlbuf.len = 0;
    strpeek.ctlbuf.buf = (char *)&ctltype;
    strpeek.databuf.maxlen = 0;
    strpeek.databuf.len = 0;
    strpeek.databuf.buf = NULL;
    strpeek.flags = 0;

    do {
        retval = ioctl(fd, I_PEEK, &strpeek);
    } while (retval < 0 && errno == EINTR);

    if (retval < 0) {
        if (_T_IS_TLI(api_semantics)) {
            /*
             * This return of T_ERROR event is ancient
             * SVR3 TLI semantics and not documented for
             * current SVR4 TLI interface.
             * Fixing this will impact some apps
             * (e.g. nfsd,lockd) in ON consolidation
             * so they need to be fixed first before TLI
             * can be fixed.
             * XXX Should we never fix this because it might
             * break apps in field ?
             */
            return (T_ERROR);
        }
        /*
         * XTI semantics (also identical to documented,
         * but not implemented TLI semantics).
         */
        t_errno = TSYSERR;
        return (-1);
    }

    /*
     * if something there and cntl part also there
     */
    if ((tiptr->ti_lookcnt > 0) ||
    ((retval > 0) && (strpeek.ctlbuf.len >= (int)sizeof (t_scalar_t)))) {
        /* LINTED pointer cast */
        pptr = (union T_primitives *)strpeek.ctlbuf.buf;
        if (tiptr->ti_lookcnt > 0) {
            /* LINTED pointer cast */
            type = *((t_scalar_t *)tiptr->ti_lookbufs.tl_lookcbuf);
            /*
             * If message on stream head is a T_DISCON_IND, that
             * has priority over a T_ORDREL_IND in the look
             * buffer.
             * (This assumes that T_ORDREL_IND can only be in the
             * first look buffer in the list)
             */
            if ((type == T_ORDREL_IND) && retval &&
                (pptr->type == T_DISCON_IND)) {
                type = pptr->type;
                /*
                 * Blow away T_ORDREL_IND
                 */
                _t_free_looklist_head(tiptr);
            }
        } else
            type = pptr->type;

        switch (type) {

        case T_CONN_IND:
            return (T_LISTEN);

        case T_CONN_CON:
            return (T_CONNECT);

        case T_DISCON_IND:
            return (T_DISCONNECT);

        case T_DATA_IND: {
            int event = T_DATA;
            int retval, exp_on_q;

            if (do_expinline_peek &&
                (tiptr->ti_prov_flag & EXPINLINE)) {
                assert(_T_IS_XTI(api_semantics));
                retval = _t_expinline_queued(fd, &exp_on_q);
                if (retval < 0) {
                    t_errno = TSYSERR;
                    return (-1);
                }
                if (exp_on_q)
                    event = T_EXDATA;
            }
            return (event);
        }

        case T_UNITDATA_IND:
            return (T_DATA);

        case T_EXDATA_IND:
            return (T_EXDATA);

        case T_UDERROR_IND:
            return (T_UDERR);

        case T_ORDREL_IND:
            return (T_ORDREL);

        default:
            t_errno = TSYSERR;
            errno = EPROTO;
            return (-1);
        }
    }

    /*
     * if something there put no control part
     * it must be data on the stream head.
     */
    if ((retval > 0) && (strpeek.ctlbuf.len <= 0)) {
        int event = T_DATA;
        int retval, exp_on_q;

        if (do_expinline_peek &&
            (tiptr->ti_prov_flag & EXPINLINE)) {
            assert(_T_IS_XTI(api_semantics));
            retval = _t_expinline_queued(fd, &exp_on_q);
            if (retval < 0)
                return (-1);
            if (exp_on_q)
                event = T_EXDATA;
        }
        return (event);
    }

    /*
     * if msg there and control
     * part not large enough to determine type?
     * it must be illegal TLI message
     */
    if ((retval > 0) && (strpeek.ctlbuf.len > 0)) {
        t_errno = TSYSERR;
        errno = EPROTO;
        return (-1);
    }
    return (0);
}