/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Attempt to dynamically link in the ZFS libzfs.so.1 so that we can
 * see if there are any ZFS zpools on any of the slices.
 */

#include <stdlib.h>
#include <stdio.h>
#include <strings.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <thread.h>
#include <synch.h>
#include <dlfcn.h>
#include <link.h>
#include <ctype.h>
#include <sys/fs/zfs.h>

#include <libzfs.h>
#include "libdiskmgt.h"
#include "disks_private.h"

/*
 * Pointers to libzfs.so functions that we dynamically resolve.
 */
static int (*zfsdl_zpool_in_use)(libzfs_handle_t *hdl, int fd,
    pool_state_t *state, char **name, boolean_t *);
static libzfs_handle_t *(*zfsdl_libzfs_init)(boolean_t);

static mutex_t                  init_lock = DEFAULTMUTEX;
static rwlock_t                 zpool_lock = DEFAULTRWLOCK;
static boolean_t                initialized;
static libzfs_handle_t          *zfs_hdl;

static void     *init_zpool();

static int
inuse_zpool_common(char *slice, nvlist_t *attrs, int *errp, char *type)
{
        int             found = 0;
        char            *name;
        int             fd;
        pool_state_t    state;
        boolean_t       used;

        *errp = 0;
        if (slice == NULL) {
            return (found);
        }

        (void) mutex_lock(&init_lock);

        /*
         * Dynamically load libzfs
         */
        if (!initialized) {
                if (!init_zpool()) {
                        (void) mutex_unlock(&init_lock);
                        return (found);
                }
                initialized = B_TRUE;
        }
        (void) mutex_unlock(&init_lock);
        (void) rw_rdlock(&zpool_lock);
        if ((fd = open(slice, O_RDONLY)) > 0) {
                name = NULL;
                if (zfsdl_zpool_in_use(zfs_hdl, fd, &state,
                    &name, &used) == 0 && used) {
                        if (strcmp(type, DM_USE_ACTIVE_ZPOOL) == 0) {
                                if (state == POOL_STATE_ACTIVE) {
                                        found = 1;
                                } else if (state == POOL_STATE_SPARE) {
                                        found = 1;
                                        type = DM_USE_SPARE_ZPOOL;
                                } else if (state == POOL_STATE_L2CACHE) {
                                        found = 1;
                                        type = DM_USE_L2CACHE_ZPOOL;
                                }
                        } else {
                                found = 1;
                        }

                        if (found) {
                                libdiskmgt_add_str(attrs, DM_USED_BY,
                                    type, errp);
                                libdiskmgt_add_str(attrs, DM_USED_NAME,
                                    name, errp);
                        }
                }
                if (name)
                        free(name);
                (void) close(fd);
        }
        (void) rw_unlock(&zpool_lock);

        return (found);
}

int
inuse_active_zpool(char *slice, nvlist_t *attrs, int *errp)
{
        return (inuse_zpool_common(slice, attrs, errp, DM_USE_ACTIVE_ZPOOL));
}

int
inuse_exported_zpool(char *slice, nvlist_t *attrs, int *errp)
{
        return (inuse_zpool_common(slice, attrs, errp, DM_USE_EXPORTED_ZPOOL));
}

/*
 * Try to dynamically link the zfs functions we need.
 */
static void*
init_zpool()
{
        void    *lh = NULL;

        if ((lh = dlopen("libzfs.so", RTLD_NOW)) == NULL) {
                return (lh);
        }

        /*
         * Instantiate the functions needed to get zpool configuration
         * data
         */
        if ((zfsdl_libzfs_init = (libzfs_handle_t *(*)(boolean_t))
            dlsym(lh, "libzfs_init")) == NULL ||
            (zfsdl_zpool_in_use = (int (*)(libzfs_handle_t *, int,
            pool_state_t *, char **, boolean_t *))
            dlsym(lh, "zpool_in_use")) == NULL) {
                (void) dlclose(lh);
                return (NULL);
        }

        if ((zfs_hdl = (*zfsdl_libzfs_init)(B_FALSE)) == NULL) {
                (void) dlclose(lh);
                return (NULL);
        }

        return (lh);
}