libmeta/common/meta_admin.c

	meta_admin.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 1992-1994, 2000-2002 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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


/*
 * miscellaneous utilities
 */

#include <meta.h>

static  int meta_fd = -1;
static  major_t meta_major;

/*
 * open administrative device
 */
int
open_admin(
    md_error_t  *ep
)
{
    struct stat buf;

    /* if not already open */
    if (meta_fd < 0) {
        ulong_t dversion = 0;

        /* try read/write fall back to readonly */
        if ((meta_fd = open(ADMSPECIAL, O_RDWR, 0)) < 0) {
            if (errno != EACCES)
                return (mdsyserror(ep, errno, ADMSPECIAL));
            if ((meta_fd = open(ADMSPECIAL, O_RDONLY, 0)) < 0)
                return (mdsyserror(ep, errno, ADMSPECIAL));
        }

        /* get major */
        if (fstat(meta_fd, &buf) != 0)
            return (mdsyserror(ep, errno, ADMSPECIAL));
        meta_major = major(buf.st_rdev);

        /* check driver version */
        if (metaioctl(MD_IOCGVERSION, &dversion, ep, NULL) != 0)
            return (-1);
        if (dversion != MD_DVERSION)
            return (mderror(ep, MDE_DVERSION, NULL));
    }

    /* return fd */
    return (meta_fd);
}

int
close_admin(
    md_error_t  *ep
)
{
    if (meta_fd >= 0) {
        if (close(meta_fd) == -1)
            return (mdsyserror(ep, errno, ADMSPECIAL));
        meta_fd = -1;
    }

    return (0);
}

/*
 * Returns True if the md_dev64_t passed in is a metadevice.
 * Else it returns False.
 */
int
meta_dev_ismeta(
    md_dev64_t  dev
)
{
    int     fd;
    md_error_t  status = mdnullerror;

    fd = open_admin(&status);
    assert(fd >= 0);
    return (meta_getmajor(dev) == meta_major);
}


int
meta_get_nunits(md_error_t *ep)
{

    static set_t        max_nunits = 0;

    if (max_nunits == 0)
        if (metaioctl(MD_IOCGETNUNITS, &max_nunits, ep, NULL) != 0)
            return (-1);

    return (max_nunits);
}

md_dev64_t
metamakedev(minor_t mnum)
{
    int     fd;
    md_error_t  status = mdnullerror;

    fd = open_admin(&status);

    assert(fd >= 0);

    return (((md_dev64_t)meta_major << NBITSMINOR64) | mnum);
}