common/io/connld.c

	connld.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * 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 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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


#pragma ident   "%Z%%M% %I% %E% SMI"    /* SVr4 1.8 */

/*
 * This module establishes a unique connection on
 * a STREAMS-based pipe.
 */
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/errno.h>
#include <sys/signal.h>
#include <sys/user.h>
#include <sys/fstyp.h>
#include <sys/stropts.h>
#include <sys/stream.h>
#include <sys/strsubr.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/fs/fifonode.h>
#include <sys/debug.h>
#include <sys/ddi.h>

/*
 * This is the loadable module wrapper.
 */
#include <sys/conf.h>
#include <sys/modctl.h>

extern struct streamtab conninfo;

static struct fmodsw fsw = {
    "connld",
    &conninfo,
    D_NEW | D_MP
};

/*
 * Module linkage information for the kernel.
 */

static struct modlstrmod modlstrmod = {
    &mod_strmodops, "Streams-based pipes", &fsw
};

static struct modlinkage modlinkage = {
    MODREV_1, (void *)&modlstrmod, NULL
};

int
_init()
{
    return (mod_install(&modlinkage));
}

int
_fini()
{
    return (mod_remove(&modlinkage));
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&modlinkage, modinfop));
}

/*
 * Define local and external routines.
 */
int connopen(queue_t *, dev_t *, int, int, cred_t *);
int connclose(queue_t *, int, cred_t *);
int connput(queue_t *, mblk_t *);

/*
 * Define STREAMS header information.
 */
static struct module_info conn_info = {
    1003,
    "connld",
    0,
    INFPSZ,
    STRHIGH,
    STRLOW
};
static struct qinit connrinit = {
    connput,
    NULL,
    connopen,
    connclose,
    NULL,
    &conn_info,
    NULL
};
static struct qinit connwinit = {
    connput,
    NULL,
    NULL,
    NULL,
    NULL,
    &conn_info,
    NULL
};
struct streamtab conninfo = {
    &connrinit,
    &connwinit
};

/*
 * For each invocation of connopen(), create a new pipe. One end of the pipe
 * is sent to the process on the other end of this STREAM. The vnode for
 * the other end is returned to the open() system call as the vnode for
 * the opened object.
 *
 * On the first invocation of connopen(), a flag is set and the routine
 * returns 0, since the first open corresponds to the pushing of the module.
 */
/*ARGSUSED*/
int
connopen(queue_t *rqp, dev_t *devp, int flag, int sflag, cred_t *crp)
{
    int error = 0;
    vnode_t *streamvp;
    fifonode_t *streamfnp;

    if ((streamvp = strq2vp(rqp)) == NULL) {
        return (EINVAL);
    }

    /*
     * CONNLD is only allowed to be pushed onto a "pipe" that has both
     * of its ends open.
     */
    if (streamvp->v_type != VFIFO) {
        error = EINVAL;
        goto out;
    }

    streamfnp = VTOF(streamvp);

    if (!(streamfnp->fn_flag & ISPIPE) ||
        streamfnp->fn_dest->fn_open == 0) {
        error = EPIPE;
        goto out;
    }

    /*
     * If this is the first time CONNLD was opened while on this stream,
     * it is being pushed. Therefore, set a flag and return 0.
     */
    if (rqp->q_ptr == 0) {
        if (streamfnp->fn_flag & FIFOCONNLD) {
            error = ENXIO;
            goto out;
        }
        rqp->q_ptr = (caddr_t)1;
        streamfnp->fn_flag |= FIFOCONNLD;
        qprocson(rqp);
    }
out:
    VN_RELE(streamvp);
    return (error);
}

/*ARGSUSED*/
int
connclose(queue_t *q, int cflag, cred_t *crp)
{
    vnode_t *streamvp;
    fifonode_t *streamfnp;

    qprocsoff(q);
    streamvp = strq2vp(q);

    ASSERT(streamvp != NULL);
    ASSERT(streamvp->v_type == VFIFO);

    streamfnp = VTOF(streamvp);
    streamfnp->fn_flag &= ~FIFOCONNLD;
    VN_RELE(streamvp);
    return (0);
}

/*
 * Use same put procedure for write and read queues.
 */
int
connput(queue_t *q, mblk_t *bp)
{
    putnext(q, bp);
    return (0);
}