common/sys/lofi.h

	lofi.h 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.
 */


#ifndef _SYS_LOFI_H
#define _SYS_LOFI_H

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

#include <sys/types.h>
#include <sys/time.h>
#include <sys/taskq.h>
#include <sys/vtoc.h>
#include <sys/dkio.h>
#include <sys/vnode.h>

#ifdef  __cplusplus
extern "C" {
#endif

/*
 * /dev names:
 *  /dev/lofictl    - master control device
 *  /dev/lofi   - block devices, named by minor number
 *  /dev/rlofi  - character devices, named by minor number
 */
#define LOFI_DRIVER_NAME    "lofi"
#define LOFI_CTL_NODE       "ctl"
#define LOFI_CTL_NAME       LOFI_DRIVER_NAME LOFI_CTL_NODE
#define LOFI_BLOCK_NAME     LOFI_DRIVER_NAME
#define LOFI_CHAR_NAME      "r" LOFI_DRIVER_NAME

/*
 *
 * Use is:
 *  ld = open("/dev/lofictl", O_RDWR | O_EXCL);
 *
 * lofi must be opened exclusively. Access is controlled by permissions on
 * the device, which is 644 by default. Write-access is required for ioctls
 * that change state, but only read-access is required for the ioctls that
 * return information. Basically, only root can add and remove files, but
 * non-root can look at the current lists.
 *
 * ioctl usage:
 *
 * kernel ioctls
 *
 *  strcpy(li.li_filename, "somefilename");
 *  ioctl(ld, LOFI_MAP_FILE, &li);
 *  newminor = li.li_minor;
 *
 *  strcpy(li.li_filename, "somefilename");
 *  ioctl(ld, LOFI_UNMAP_FILE, &li);
 *
 *  strcpy(li.li_filename, "somefilename");
 *  li.li_minor = minor_number;
 *  ioctl(ld, LOFI_MAP_FILE_MINOR, &li);
 *
 *  li.li_minor = minor_number;
 *  ioctl(ld, LOFI_UNMAP_FILE_MINOR, &li);
 *
 *  li.li_minor = minor_number;
 *  ioctl(ld, LOFI_GET_FILENAME, &li);
 *
 *  strcpy(li.li_filename, "somefilename");
 *  ioctl(ld, LOFI_GET_MINOR, &li);
 *
 *  li.li_minor = 0;
 *  ioctl(ld, LOFI_GET_MAXMINOR, &li);
 *  maxminor = li.li_minor;
 *
 * Oh, and last but not least: these ioctls are totally private and only
 * for use by lofiadm(1M).
 *
 */

struct lofi_ioctl {
    uint32_t li_minor;
    char    li_filename[MAXPATHLEN + 1];
};

#define LOFI_IOC_BASE       (('L' << 16) | ('F' << 8))

#define LOFI_MAP_FILE       (LOFI_IOC_BASE | 0x01)
#define LOFI_MAP_FILE_MINOR (LOFI_IOC_BASE | 0x02)
#define LOFI_UNMAP_FILE     (LOFI_IOC_BASE | 0x03)
#define LOFI_UNMAP_FILE_MINOR   (LOFI_IOC_BASE | 0x04)
#define LOFI_GET_FILENAME   (LOFI_IOC_BASE | 0x05)
#define LOFI_GET_MINOR      (LOFI_IOC_BASE | 0x06)
#define LOFI_GET_MAXMINOR   (LOFI_IOC_BASE | 0x07)

/*
 * file types that might be usable with lofi, maybe. Only regular
 * files are documented though.
 */
#define S_ISLOFIABLE(mode) \
    (S_ISREG(mode) || S_ISBLK(mode) || S_ISCHR(mode))

#if defined(_KERNEL)

/*
 * We limit the maximum number of active lofi devices to 128, which seems very
 * large. You can tune this by changing lofi_max_files in /etc/system.
 * If you change it dynamically, which you probably shouldn't do, make sure
 * to only _increase_ it.
 */
#define LOFI_MAX_FILES  128
extern uint32_t lofi_max_files;

#define V_ISLOFIABLE(vtype) \
    ((vtype == VREG) || (vtype == VBLK) || (vtype == VCHR))

struct lofi_state {
    char    *ls_filename;   /* filename to open */
    size_t  ls_filename_sz;
    struct vnode    *ls_vp; /* open vnode */
    u_offset_t  ls_vp_size;
    uint32_t    ls_blk_open;
    uint32_t    ls_chr_open;
    uint32_t    ls_lyr_open_count;
    int     ls_openflag;
    taskq_t     *ls_taskq;
    kstat_t     *ls_kstat;
    kmutex_t    ls_kstat_lock;
    struct dk_geom  ls_dkg;
    struct vtoc ls_vtoc;
    struct dk_cinfo ls_ci;
};

#endif

#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_LOFI_H */