/*
 * 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 (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
 * Copyright 2016 Syneto S.R.L. All rights reserved.
 * Copyright (c) 2016 by Delphix. All rights reserved.
 */

/*
 * General Structures Layout
 * -------------------------
 *
 * This is a simplified diagram showing the relationship between most of the
 * main structures.
 *
 * +-------------------+
 * |     SMB_INFO      |
 * +-------------------+
 *          |
 *          |
 *          v
 * +-------------------+       +-------------------+      +-------------------+
 * |     SESSION       |<----->|     SESSION       |......|      SESSION      |
 * +-------------------+       +-------------------+      +-------------------+
 *   |          |
 *   |          |
 *   |          v
 *   |  +-------------------+     +-------------------+   +-------------------+
 *   |  |       USER        |<--->|       USER        |...|       USER        |
 *   |  +-------------------+     +-------------------+   +-------------------+
 *   |
 *   |
 *   v
 * +-------------------+       +-------------------+      +-------------------+
 * |       TREE        |<----->|       TREE        |......|       TREE        |
 * +-------------------+       +-------------------+      +-------------------+
 *      |         |
 *      |         |
 *      |         v
 *      |     +-------+       +-------+      +-------+
 *      |     | OFILE |<----->| OFILE |......| OFILE |
 *      |     +-------+       +-------+      +-------+
 *      |
 *      |
 *      v
 *  +-------+       +------+      +------+
 *  | ODIR  |<----->| ODIR |......| ODIR |
 *  +-------+       +------+      +------+
 *
 *
 * Ofile State Machine
 * ------------------
 *
 *    +-------------------------+	 T0
 *    |  SMB_OFILE_STATE_OPEN   |<----------- Creation/Allocation
 *    +-------------------------+
 *		    |
 *		    | T1
 *		    |
 *		    v
 *    +-------------------------+
 *    | SMB_OFILE_STATE_CLOSING |
 *    +-------------------------+
 *		    |
 *		    | T2
 *		    |
 *		    v
 *    +-------------------------+    T3
 *    | SMB_OFILE_STATE_CLOSED  |----------> Deletion/Free
 *    +-------------------------+
 *
 * SMB_OFILE_STATE_OPEN
 *
 *    While in this state:
 *      - The ofile is queued in the list of ofiles of its tree.
 *      - References will be given out if the ofile is looked up.
 *
 * SMB_OFILE_STATE_CLOSING
 *
 *    While in this state:
 *      - The ofile is queued in the list of ofiles of its tree.
 *      - References will not be given out if the ofile is looked up.
 *      - The file is closed and the locks held are being released.
 *      - The resources associated with the ofile remain.
 *
 * SMB_OFILE_STATE_CLOSED
 *
 *    While in this state:
 *      - The ofile is queued in the list of ofiles of its tree.
 *      - References will not be given out if the ofile is looked up.
 *      - The resources associated with the ofile remain.
 *
 * Transition T0
 *
 *    This transition occurs in smb_ofile_open(). A new ofile is created and
 *    added to the list of ofiles of a tree.
 *
 * Transition T1
 *
 *    This transition occurs in smb_ofile_close().
 *
 * Transition T2
 *
 *    This transition occurs in smb_ofile_release(). The resources associated
 *    with the ofile are freed as well as the ofile structure. For the
 *    transition to occur, the ofile must be in the SMB_OFILE_STATE_CLOSED
 *    state and the reference count be zero.
 *
 * Comments
 * --------
 *
 *    The state machine of the ofile structures is controlled by 3 elements:
 *      - The list of ofiles of the tree it belongs to.
 *      - The mutex embedded in the structure itself.
 *      - The reference count.
 *
 *    There's a mutex embedded in the ofile structure used to protect its fields
 *    and there's a lock embedded in the list of ofiles of a tree. To
 *    increment or to decrement the reference count the mutex must be entered.
 *    To insert the ofile into the list of ofiles of the tree and to remove
 *    the ofile from it, the lock must be entered in RW_WRITER mode.
 *
 *    Rules of access to a ofile structure:
 *
 *    1) In order to avoid deadlocks, when both (mutex and lock of the ofile
 *       list) have to be entered, the lock must be entered first.
 *
 *    2) All actions applied to an ofile require a reference count.
 *
 *    3) There are 2 ways of getting a reference count. One is when the ofile
 *       is opened. The other one when the ofile is looked up. This translates
 *       into 2 functions: smb_ofile_open() and smb_ofile_lookup_by_fid().
 *
 *    It should be noted that the reference count of an ofile registers the
 *    number of references to the ofile in other structures (such as an smb
 *    request). The reference count is not incremented in these 2 instances:
 *
 *    1) The ofile is open. An ofile is anchored by its state. If there's
 *       no activity involving an ofile currently open, the reference count
 *       of that ofile is zero.
 *
 *    2) The ofile is queued in the list of ofiles of its tree. The fact of
 *       being queued in that list is NOT registered by incrementing the
 *       reference count.
 */
#include <smbsrv/smb_kproto.h>
#include <smbsrv/smb_fsops.h>

static boolean_t smb_ofile_is_open_locked(smb_ofile_t *);
static smb_ofile_t *smb_ofile_close_and_next(smb_ofile_t *);
static int smb_ofile_netinfo_encode(smb_ofile_t *, uint8_t *, size_t,
    uint32_t *);
static int smb_ofile_netinfo_init(smb_ofile_t *, smb_netfileinfo_t *);
static void smb_ofile_netinfo_fini(smb_netfileinfo_t *);

/*
 * smb_ofile_open
 */
smb_ofile_t *
smb_ofile_open(
    smb_request_t	*sr,
    smb_node_t		*node,
    struct open_param	*op,
    uint16_t		ftype,
    uint32_t		uniqid,
    smb_error_t		*err)
{
	smb_tree_t	*tree = sr->tid_tree;
	smb_ofile_t	*of;
	uint16_t	fid;
	smb_attr_t	attr;
	int		rc;
	enum errstates { EMPTY, FIDALLOC, CRHELD, MUTEXINIT };
	enum errstates	state = EMPTY;

	if (smb_idpool_alloc(&tree->t_fid_pool, &fid)) {
		err->status = NT_STATUS_TOO_MANY_OPENED_FILES;
		err->errcls = ERRDOS;
		err->errcode = ERROR_TOO_MANY_OPEN_FILES;
		return (NULL);
	}
	state = FIDALLOC;

	of = kmem_cache_alloc(smb_cache_ofile, KM_SLEEP);
	bzero(of, sizeof (smb_ofile_t));
	of->f_magic = SMB_OFILE_MAGIC;
	of->f_refcnt = 1;
	of->f_fid = fid;
	of->f_uniqid = uniqid;
	of->f_opened_by_pid = sr->smb_pid;
	of->f_granted_access = op->desired_access;
	of->f_share_access = op->share_access;
	of->f_create_options = op->create_options;
	of->f_cr = (op->create_options & FILE_OPEN_FOR_BACKUP_INTENT) ?
	    smb_user_getprivcred(sr->uid_user) : sr->uid_user->u_cred;
	crhold(of->f_cr);
	state = CRHELD;
	of->f_ftype = ftype;
	of->f_server = tree->t_server;
	of->f_session = tree->t_session;
	/*
	 * grab a ref for of->f_user
	 * released in smb_ofile_delete()
	 */
	smb_user_hold_internal(sr->uid_user);
	of->f_user = sr->uid_user;
	of->f_tree = tree;
	of->f_node = node;

	mutex_init(&of->f_mutex, NULL, MUTEX_DEFAULT, NULL);
	state = MUTEXINIT;
	of->f_state = SMB_OFILE_STATE_OPEN;

	if (ftype == SMB_FTYPE_MESG_PIPE) {
		/* See smb_opipe_open. */
		of->f_pipe = op->pipe;
		smb_server_inc_pipes(of->f_server);
	} else {
		ASSERT(ftype == SMB_FTYPE_DISK); /* Regular file, not a pipe */
		ASSERT(node);

		/*
		 * Note that the common open path often adds bits like
		 * READ_CONTROL, so the logic "is this open exec-only"
		 * needs to look at only the FILE_DATA_ALL bits.
		 */
		if ((of->f_granted_access & FILE_DATA_ALL) == FILE_EXECUTE)
			of->f_flags |= SMB_OFLAGS_EXECONLY;

		bzero(&attr, sizeof (smb_attr_t));
		attr.sa_mask = SMB_AT_UID | SMB_AT_DOSATTR;
		rc = smb_node_getattr(NULL, node, of->f_cr, NULL, &attr);
		if (rc != 0) {
			err->status = NT_STATUS_INTERNAL_ERROR;
			err->errcls = ERRDOS;
			err->errcode = ERROR_INTERNAL_ERROR;
			goto errout;
		}
		if (crgetuid(of->f_cr) == attr.sa_vattr.va_uid) {
			/*
			 * Add this bit for the file's owner even if it's not
			 * specified in the request (Windows behavior).
			 */
			of->f_granted_access |= FILE_READ_ATTRIBUTES;
		}

		if (smb_node_is_file(node)) {
			of->f_mode =
			    smb_fsop_amask_to_omode(of->f_granted_access);
			if (smb_fsop_open(node, of->f_mode, of->f_cr) != 0) {
				err->status = NT_STATUS_ACCESS_DENIED;
				err->errcls = ERRDOS;
				err->errcode = ERROR_ACCESS_DENIED;
				goto errout;
			}
		}

		if (tree->t_flags & SMB_TREE_READONLY)
			of->f_flags |= SMB_OFLAGS_READONLY;

		/*
		 * Note that if we created_readonly, that
		 * will _not_ yet show in attr.sa_dosattr
		 * so creating a readonly file gives the
		 * caller a writable handle as it should.
		 */
		if (attr.sa_dosattr & FILE_ATTRIBUTE_READONLY)
			of->f_flags |= SMB_OFLAGS_READONLY;

		smb_node_inc_open_ofiles(node);
		smb_node_add_ofile(node, of);
		smb_node_ref(node);
		smb_server_inc_files(of->f_server);
	}
	smb_llist_enter(&tree->t_ofile_list, RW_WRITER);
	smb_llist_insert_tail(&tree->t_ofile_list, of);
	smb_llist_exit(&tree->t_ofile_list);
	atomic_inc_32(&tree->t_open_files);
	atomic_inc_32(&of->f_session->s_file_cnt);
	return (of);

errout:
	switch (state) {
	case MUTEXINIT:
		mutex_destroy(&of->f_mutex);
		smb_user_release(of->f_user);
		/*FALLTHROUGH*/
	case CRHELD:
		crfree(of->f_cr);
		of->f_magic = 0;
		kmem_cache_free(smb_cache_ofile, of);
		/*FALLTHROUGH*/
	case FIDALLOC:
		smb_idpool_free(&tree->t_fid_pool, fid);
		/*FALLTHROUGH*/
	case EMPTY:
		break;
	}
	return (NULL);
}

/*
 * smb_ofile_close
 */
void
smb_ofile_close(smb_ofile_t *of, int32_t mtime_sec)
{
	smb_attr_t *pa;
	timestruc_t now;
	uint32_t flags = 0;

	SMB_OFILE_VALID(of);

	mutex_enter(&of->f_mutex);
	ASSERT(of->f_refcnt);
	if (of->f_state != SMB_OFILE_STATE_OPEN) {
		mutex_exit(&of->f_mutex);
		return;
	}
	of->f_state = SMB_OFILE_STATE_CLOSING;
	mutex_exit(&of->f_mutex);

	switch (of->f_ftype) {
	case SMB_FTYPE_BYTE_PIPE:
	case SMB_FTYPE_MESG_PIPE:
		smb_opipe_close(of);
		smb_server_dec_pipes(of->f_server);
		break;

	case SMB_FTYPE_DISK:
	case SMB_FTYPE_PRINTER:
		/*
		 * In here we make changes to of->f_pending_attr
		 * while not holding of->f_mutex.  This is OK
		 * because we've changed f_state to CLOSING,
		 * so no more threads will take this path.
		 */
		pa = &of->f_pending_attr;
		if (mtime_sec != 0) {
			pa->sa_vattr.va_mtime.tv_sec = mtime_sec;
			pa->sa_mask |= SMB_AT_MTIME;
		}

		/*
		 * If we have ever modified data via this handle
		 * (write or truncate) and if the mtime was not
		 * set via this handle, update the mtime again
		 * during the close.  Windows expects this.
		 * [ MS-FSA 2.1.5.4 "Update Timestamps" ]
		 */
		if (of->f_written &&
		    (pa->sa_mask & SMB_AT_MTIME) == 0) {
			pa->sa_mask |= SMB_AT_MTIME;
			gethrestime(&now);
			pa->sa_vattr.va_mtime = now;
		}

		if (of->f_flags & SMB_OFLAGS_SET_DELETE_ON_CLOSE) {
			if (smb_tree_has_feature(of->f_tree,
			    SMB_TREE_CATIA)) {
				flags |= SMB_CATIA;
			}
			(void) smb_node_set_delete_on_close(of->f_node,
			    of->f_cr, flags);
		}
		smb_fsop_unshrlock(of->f_cr, of->f_node, of->f_uniqid);
		smb_node_destroy_lock_by_ofile(of->f_node, of);

		if (smb_node_is_file(of->f_node)) {
			(void) smb_fsop_close(of->f_node, of->f_mode,
			    of->f_cr);
			smb_oplock_release(of->f_node, of);
		} else {
			/*
			 * If there was an odir, close it.
			 */
			if (of->f_odir != NULL)
				smb_odir_close(of->f_odir);
		}
		if (smb_node_dec_open_ofiles(of->f_node) == 0) {
			/*
			 * Last close. The f_pending_attr has
			 * only times (atime,ctime,mtime) so
			 * we can borrow it to commit the
			 * n_pending_dosattr from the node.
			 */
			pa->sa_dosattr =
			    of->f_node->n_pending_dosattr;
			if (pa->sa_dosattr != 0)
				pa->sa_mask |= SMB_AT_DOSATTR;
			/* Let's leave this zero when not in use. */
			of->f_node->n_allocsz = 0;
		}
		if (pa->sa_mask != 0) {
			/*
			 * Commit any pending attributes from
			 * the ofile we're closing.  Note that
			 * we pass NULL as the ofile to setattr
			 * so it will write to the file system
			 * and not keep anything on the ofile.
			 * This clears n_pending_dosattr if
			 * there are no opens, otherwise the
			 * dosattr will be pending again.
			 */
			(void) smb_node_setattr(NULL, of->f_node,
			    of->f_cr, NULL, pa);
		}

		/*
		 * Cancel any notify change requests that
		 * may be using this open instance.
		 */
		if (of->f_node->n_fcn.fcn_count)
			smb_notify_file_closed(of);

		smb_server_dec_files(of->f_server);
		break;
	}
	atomic_dec_32(&of->f_tree->t_open_files);

	mutex_enter(&of->f_mutex);
	ASSERT(of->f_refcnt);
	ASSERT(of->f_state == SMB_OFILE_STATE_CLOSING);
	of->f_state = SMB_OFILE_STATE_CLOSED;
	mutex_exit(&of->f_mutex);
}

/*
 * smb_ofile_close_all
 *
 *
 */
void
smb_ofile_close_all(
    smb_tree_t		*tree)
{
	smb_ofile_t	*of;

	ASSERT(tree);
	ASSERT(tree->t_magic == SMB_TREE_MAGIC);

	smb_llist_enter(&tree->t_ofile_list, RW_READER);
	of = smb_llist_head(&tree->t_ofile_list);
	while (of) {
		ASSERT(of->f_magic == SMB_OFILE_MAGIC);
		ASSERT(of->f_tree == tree);
		of = smb_ofile_close_and_next(of);
	}
	smb_llist_exit(&tree->t_ofile_list);
}

/*
 * smb_ofiles_close_by_pid
 *
 *
 */
void
smb_ofile_close_all_by_pid(
    smb_tree_t		*tree,
    uint16_t		pid)
{
	smb_ofile_t	*of;

	ASSERT(tree);
	ASSERT(tree->t_magic == SMB_TREE_MAGIC);

	smb_llist_enter(&tree->t_ofile_list, RW_READER);
	of = smb_llist_head(&tree->t_ofile_list);
	while (of) {
		ASSERT(of->f_magic == SMB_OFILE_MAGIC);
		ASSERT(of->f_tree == tree);
		if (of->f_opened_by_pid == pid) {
			of = smb_ofile_close_and_next(of);
		} else {
			of = smb_llist_next(&tree->t_ofile_list, of);
		}
	}
	smb_llist_exit(&tree->t_ofile_list);
}

/*
 * If the enumeration request is for ofile data, handle it here.
 * Otherwise, return.
 *
 * This function should be called with a hold on the ofile.
 */
int
smb_ofile_enum(smb_ofile_t *of, smb_svcenum_t *svcenum)
{
	uint8_t *pb;
	uint_t nbytes;
	int rc;

	ASSERT(of);
	ASSERT(of->f_magic == SMB_OFILE_MAGIC);
	ASSERT(of->f_refcnt);

	if (svcenum->se_type != SMB_SVCENUM_TYPE_FILE)
		return (0);

	if (svcenum->se_nskip > 0) {
		svcenum->se_nskip--;
		return (0);
	}

	if (svcenum->se_nitems >= svcenum->se_nlimit) {
		svcenum->se_nitems = svcenum->se_nlimit;
		return (0);
	}

	pb = &svcenum->se_buf[svcenum->se_bused];

	rc = smb_ofile_netinfo_encode(of, pb, svcenum->se_bavail,
	    &nbytes);
	if (rc == 0) {
		svcenum->se_bavail -= nbytes;
		svcenum->se_bused += nbytes;
		svcenum->se_nitems++;
	}

	return (rc);
}

/*
 * Take a reference on an open file.
 */
boolean_t
smb_ofile_hold(smb_ofile_t *of)
{
	ASSERT(of);
	ASSERT(of->f_magic == SMB_OFILE_MAGIC);

	mutex_enter(&of->f_mutex);

	if (of->f_state != SMB_OFILE_STATE_OPEN) {
		mutex_exit(&of->f_mutex);
		return (B_FALSE);
	}
	of->f_refcnt++;

	mutex_exit(&of->f_mutex);
	return (B_TRUE);
}

/*
 * Release a reference on a file.  If the reference count falls to
 * zero and the file has been closed, post the object for deletion.
 * Object deletion is deferred to avoid modifying a list while an
 * iteration may be in progress.
 */
void
smb_ofile_release(smb_ofile_t *of)
{
	SMB_OFILE_VALID(of);

	mutex_enter(&of->f_mutex);
	ASSERT(of->f_refcnt);
	of->f_refcnt--;
	switch (of->f_state) {
	case SMB_OFILE_STATE_OPEN:
	case SMB_OFILE_STATE_CLOSING:
		break;

	case SMB_OFILE_STATE_CLOSED:
		if (of->f_refcnt == 0)
			smb_tree_post_ofile(of->f_tree, of);
		break;

	default:
		ASSERT(0);
		break;
	}
	mutex_exit(&of->f_mutex);
}

/*
 * smb_ofile_request_complete
 *
 * During oplock acquisition, all other oplock requests on the node
 * are blocked until the acquire request completes and the response
 * is on the wire.
 * Call smb_oplock_broadcast to notify the node that the request
 * has completed.
 *
 * THIS MECHANISM RELIES ON THE FACT THAT THE OFILE IS NOT REMOVED
 * FROM THE SR UNTIL REQUEST COMPLETION (when the sr is destroyed)
 */
void
smb_ofile_request_complete(smb_ofile_t *of)
{
	SMB_OFILE_VALID(of);

	switch (of->f_ftype) {
	case SMB_FTYPE_DISK:
		ASSERT(of->f_node);
		smb_oplock_broadcast(of->f_node);
		break;
	case SMB_FTYPE_MESG_PIPE:
		break;
	default:
		break;
	}
}

/*
 * smb_ofile_lookup_by_fid
 *
 * Find the open file whose fid matches the one specified in the request.
 * If we can't find the fid or the shares (trees) don't match, we have a
 * bad fid.
 */
smb_ofile_t *
smb_ofile_lookup_by_fid(
    smb_request_t	*sr,
    uint16_t		fid)
{
	smb_tree_t	*tree = sr->tid_tree;
	smb_llist_t	*of_list;
	smb_ofile_t	*of;

	ASSERT(tree->t_magic == SMB_TREE_MAGIC);

	of_list = &tree->t_ofile_list;

	smb_llist_enter(of_list, RW_READER);
	of = smb_llist_head(of_list);
	while (of) {
		ASSERT(of->f_magic == SMB_OFILE_MAGIC);
		ASSERT(of->f_tree == tree);
		if (of->f_fid == fid)
			break;
		of = smb_llist_next(of_list, of);
	}
	if (of == NULL)
		goto out;

	/*
	 * Only allow use of a given FID with the same UID that
	 * was used to open it.  MS-CIFS 3.3.5.14
	 */
	if (of->f_user != sr->uid_user) {
		of = NULL;
		goto out;
	}

	mutex_enter(&of->f_mutex);
	if (of->f_state != SMB_OFILE_STATE_OPEN) {
		mutex_exit(&of->f_mutex);
		of = NULL;
		goto out;
	}
	of->f_refcnt++;
	mutex_exit(&of->f_mutex);

out:
	smb_llist_exit(of_list);
	return (of);
}

/*
 * smb_ofile_lookup_by_uniqid
 *
 * Find the open file whose uniqid matches the one specified in the request.
 */
smb_ofile_t *
smb_ofile_lookup_by_uniqid(smb_tree_t *tree, uint32_t uniqid)
{
	smb_llist_t	*of_list;
	smb_ofile_t	*of;

	ASSERT(tree->t_magic == SMB_TREE_MAGIC);

	of_list = &tree->t_ofile_list;
	smb_llist_enter(of_list, RW_READER);
	of = smb_llist_head(of_list);

	while (of) {
		ASSERT(of->f_magic == SMB_OFILE_MAGIC);
		ASSERT(of->f_tree == tree);

		if (of->f_uniqid == uniqid) {
			if (smb_ofile_hold(of)) {
				smb_llist_exit(of_list);
				return (of);
			}
		}

		of = smb_llist_next(of_list, of);
	}

	smb_llist_exit(of_list);
	return (NULL);
}

/*
 * Disallow NetFileClose on certain ofiles to avoid side-effects.
 * Closing a tree root is not allowed: use NetSessionDel or NetShareDel.
 * Closing SRVSVC connections is not allowed because this NetFileClose
 * request may depend on this ofile.
 */
boolean_t
smb_ofile_disallow_fclose(smb_ofile_t *of)
{
	ASSERT(of);
	ASSERT(of->f_magic == SMB_OFILE_MAGIC);
	ASSERT(of->f_refcnt);

	switch (of->f_ftype) {
	case SMB_FTYPE_DISK:
		ASSERT(of->f_tree);
		return (of->f_node == of->f_tree->t_snode);

	case SMB_FTYPE_MESG_PIPE:
		ASSERT(of->f_pipe);
		if (smb_strcasecmp(of->f_pipe->p_name, "SRVSVC", 0) == 0)
			return (B_TRUE);
		break;
	default:
		break;
	}

	return (B_FALSE);
}

/*
 * smb_ofile_set_flags
 *
 * Return value:
 *
 *	Current flags value
 *
 */
void
smb_ofile_set_flags(
    smb_ofile_t		*of,
    uint32_t		flags)
{
	ASSERT(of);
	ASSERT(of->f_magic == SMB_OFILE_MAGIC);
	ASSERT(of->f_refcnt);

	mutex_enter(&of->f_mutex);
	of->f_flags |= flags;
	mutex_exit(&of->f_mutex);
}

/*
 * smb_ofile_seek
 *
 * Return value:
 *
 *	0		Success
 *	EINVAL		Unknown mode
 *	EOVERFLOW	offset too big
 *
 */
int
smb_ofile_seek(
    smb_ofile_t		*of,
    ushort_t		mode,
    int32_t		off,
    uint32_t		*retoff)
{
	u_offset_t	newoff = 0;
	int		rc = 0;
	smb_attr_t	attr;

	ASSERT(of);
	ASSERT(of->f_magic == SMB_OFILE_MAGIC);
	ASSERT(of->f_refcnt);

	mutex_enter(&of->f_mutex);
	switch (mode) {
	case SMB_SEEK_SET:
		if (off < 0)
			newoff = 0;
		else
			newoff = (u_offset_t)off;
		break;

	case SMB_SEEK_CUR:
		if (off < 0 && (-off) > of->f_seek_pos)
			newoff = 0;
		else
			newoff = of->f_seek_pos + (u_offset_t)off;
		break;

	case SMB_SEEK_END:
		bzero(&attr, sizeof (smb_attr_t));
		attr.sa_mask |= SMB_AT_SIZE;
		rc = smb_fsop_getattr(NULL, zone_kcred(), of->f_node, &attr);
		if (rc != 0) {
			mutex_exit(&of->f_mutex);
			return (rc);
		}
		if (off < 0 && (-off) > attr.sa_vattr.va_size)
			newoff = 0;
		else
			newoff = attr.sa_vattr.va_size + (u_offset_t)off;
		break;

	default:
		mutex_exit(&of->f_mutex);
		return (EINVAL);
	}

	/*
	 * See comments at the beginning of smb_seek.c.
	 * If the offset is greater than UINT_MAX, we will return an error.
	 */

	if (newoff > UINT_MAX) {
		rc = EOVERFLOW;
	} else {
		of->f_seek_pos = newoff;
		*retoff = (uint32_t)newoff;
	}
	mutex_exit(&of->f_mutex);
	return (rc);
}

/*
 * smb_ofile_flush
 *
 * If writes on this file are not synchronous, flush it using the NFSv3
 * commit interface.
 *
 * XXX - todo: Flush named pipe should drain writes.
 */
void
smb_ofile_flush(struct smb_request *sr, struct smb_ofile *of)
{
	switch (of->f_ftype) {
	case SMB_FTYPE_DISK:
		if ((of->f_node->flags & NODE_FLAGS_WRITE_THROUGH) == 0)
			(void) smb_fsop_commit(sr, of->f_cr, of->f_node);
		break;
	default:
		break;
	}
}

/*
 * smb_ofile_is_open
 */
boolean_t
smb_ofile_is_open(smb_ofile_t *of)
{
	boolean_t	rc;

	SMB_OFILE_VALID(of);

	mutex_enter(&of->f_mutex);
	rc = smb_ofile_is_open_locked(of);
	mutex_exit(&of->f_mutex);
	return (rc);
}

/* *************************** Static Functions ***************************** */

/*
 * Determine whether or not an ofile is open.
 * This function must be called with the mutex held.
 */
static boolean_t
smb_ofile_is_open_locked(smb_ofile_t *of)
{
	switch (of->f_state) {
	case SMB_OFILE_STATE_OPEN:
		return (B_TRUE);

	case SMB_OFILE_STATE_CLOSING:
	case SMB_OFILE_STATE_CLOSED:
		return (B_FALSE);

	default:
		ASSERT(0);
		return (B_FALSE);
	}
}

/*
 * This function closes the file passed in (if appropriate) and returns the
 * next open file in the list of open files of the tree of the open file passed
 * in. It requires that the list of open files of the tree be entered in
 * RW_READER mode before being called.
 */
static smb_ofile_t *
smb_ofile_close_and_next(smb_ofile_t *of)
{
	smb_ofile_t	*next_of;
	smb_tree_t	*tree;

	ASSERT(of);
	ASSERT(of->f_magic == SMB_OFILE_MAGIC);

	mutex_enter(&of->f_mutex);
	switch (of->f_state) {
	case SMB_OFILE_STATE_OPEN:
		/* The file is still open. */
		of->f_refcnt++;
		ASSERT(of->f_refcnt);
		tree = of->f_tree;
		mutex_exit(&of->f_mutex);
		smb_llist_exit(&of->f_tree->t_ofile_list);
		smb_ofile_close(of, 0);
		smb_ofile_release(of);
		smb_llist_enter(&tree->t_ofile_list, RW_READER);
		next_of = smb_llist_head(&tree->t_ofile_list);
		break;
	case SMB_OFILE_STATE_CLOSING:
	case SMB_OFILE_STATE_CLOSED:
		/*
		 * The ofile exists but is closed or
		 * in the process being closed.
		 */
		mutex_exit(&of->f_mutex);
		next_of = smb_llist_next(&of->f_tree->t_ofile_list, of);
		break;
	default:
		ASSERT(0);
		mutex_exit(&of->f_mutex);
		next_of = smb_llist_next(&of->f_tree->t_ofile_list, of);
		break;
	}
	return (next_of);
}

/*
 * Delete an ofile.
 *
 * Remove the ofile from the tree list before freeing resources
 * associated with the ofile.
 */
void
smb_ofile_delete(void *arg)
{
	smb_tree_t	*tree;
	smb_ofile_t	*of = (smb_ofile_t *)arg;

	SMB_OFILE_VALID(of);
	ASSERT(of->f_refcnt == 0);
	ASSERT(of->f_state == SMB_OFILE_STATE_CLOSED);
	ASSERT(!SMB_OFILE_OPLOCK_GRANTED(of));

	tree = of->f_tree;
	smb_llist_enter(&tree->t_ofile_list, RW_WRITER);
	smb_llist_remove(&tree->t_ofile_list, of);
	smb_idpool_free(&tree->t_fid_pool, of->f_fid);
	atomic_dec_32(&tree->t_session->s_file_cnt);
	smb_llist_exit(&tree->t_ofile_list);

	mutex_enter(&of->f_mutex);
	mutex_exit(&of->f_mutex);

	switch (of->f_ftype) {
	case SMB_FTYPE_BYTE_PIPE:
	case SMB_FTYPE_MESG_PIPE:
		smb_opipe_dealloc(of->f_pipe);
		of->f_pipe = NULL;
		break;
	case SMB_FTYPE_DISK:
		if (of->f_odir != NULL)
			smb_odir_release(of->f_odir);
		smb_node_rem_ofile(of->f_node, of);
		smb_node_release(of->f_node);
		break;
	default:
		ASSERT(!"f_ftype");
		break;
	}

	of->f_magic = (uint32_t)~SMB_OFILE_MAGIC;
	mutex_destroy(&of->f_mutex);
	crfree(of->f_cr);
	smb_user_release(of->f_user);
	kmem_cache_free(smb_cache_ofile, of);
}

/*
 * smb_ofile_access
 *
 * This function will check to see if the access requested is granted.
 * Returns NT status codes.
 */
uint32_t
smb_ofile_access(smb_ofile_t *of, cred_t *cr, uint32_t access)
{

	if ((of == NULL) || (cr == zone_kcred()))
		return (NT_STATUS_SUCCESS);

	/*
	 * If the request is for something
	 * I don't grant it is an error
	 */
	if (~(of->f_granted_access) & access) {
		if (!(of->f_granted_access & ACCESS_SYSTEM_SECURITY) &&
		    (access & ACCESS_SYSTEM_SECURITY)) {
			return (NT_STATUS_PRIVILEGE_NOT_HELD);
		}
		return (NT_STATUS_ACCESS_DENIED);
	}

	return (NT_STATUS_SUCCESS);
}

/*
 * smb_ofile_share_check
 *
 * Check if ofile was opened with share access NONE (0).
 * Returns: B_TRUE  - share access non-zero
 *          B_FALSE - share access NONE
 */
boolean_t
smb_ofile_share_check(smb_ofile_t *of)
{
	return (!SMB_DENY_ALL(of->f_share_access));
}

/*
 * check file sharing rules for current open request
 * against existing open instances of the same file
 *
 * Returns NT_STATUS_SHARING_VIOLATION if there is any
 * sharing conflict, otherwise returns NT_STATUS_SUCCESS.
 */
uint32_t
smb_ofile_open_check(smb_ofile_t *of, uint32_t desired_access,
    uint32_t share_access)
{
	ASSERT(of->f_magic == SMB_OFILE_MAGIC);

	mutex_enter(&of->f_mutex);

	if (of->f_state != SMB_OFILE_STATE_OPEN) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_INVALID_HANDLE);
	}

	/* if it's just meta data */
	if ((of->f_granted_access & FILE_DATA_ALL) == 0) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_SUCCESS);
	}

	/*
	 * Check requested share access against the
	 * open granted (desired) access
	 */
	if (SMB_DENY_DELETE(share_access) && (of->f_granted_access & DELETE)) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_SHARING_VIOLATION);
	}

	if (SMB_DENY_READ(share_access) &&
	    (of->f_granted_access & (FILE_READ_DATA | FILE_EXECUTE))) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_SHARING_VIOLATION);
	}

	if (SMB_DENY_WRITE(share_access) &&
	    (of->f_granted_access & (FILE_WRITE_DATA | FILE_APPEND_DATA))) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_SHARING_VIOLATION);
	}

	/* check requested desired access against the open share access */
	if (SMB_DENY_DELETE(of->f_share_access) && (desired_access & DELETE)) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_SHARING_VIOLATION);
	}

	if (SMB_DENY_READ(of->f_share_access) &&
	    (desired_access & (FILE_READ_DATA | FILE_EXECUTE))) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_SHARING_VIOLATION);
	}

	if (SMB_DENY_WRITE(of->f_share_access) &&
	    (desired_access & (FILE_WRITE_DATA | FILE_APPEND_DATA))) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_SHARING_VIOLATION);
	}

	mutex_exit(&of->f_mutex);
	return (NT_STATUS_SUCCESS);
}

/*
 * smb_ofile_rename_check
 *
 * An open file can be renamed if
 *
 *  1. isn't opened for data writing or deleting
 *
 *  2. Opened with "Deny Delete" share mode
 *         But not opened for data reading or executing
 *         (opened for accessing meta data)
 */

uint32_t
smb_ofile_rename_check(smb_ofile_t *of)
{
	ASSERT(of->f_magic == SMB_OFILE_MAGIC);

	mutex_enter(&of->f_mutex);

	if (of->f_state != SMB_OFILE_STATE_OPEN) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_INVALID_HANDLE);
	}

	if (of->f_granted_access &
	    (FILE_WRITE_DATA | FILE_APPEND_DATA | DELETE)) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_SHARING_VIOLATION);
	}

	if ((of->f_share_access & FILE_SHARE_DELETE) == 0) {
		if (of->f_granted_access &
		    (FILE_READ_DATA | FILE_EXECUTE)) {
			mutex_exit(&of->f_mutex);
			return (NT_STATUS_SHARING_VIOLATION);
		}
	}

	mutex_exit(&of->f_mutex);
	return (NT_STATUS_SUCCESS);
}

/*
 * smb_ofile_delete_check
 *
 * An open file can be deleted only if opened for
 * accessing meta data. Share modes aren't important
 * in this case.
 *
 * NOTE: there is another mechanism for deleting an
 * open file that NT clients usually use.
 * That's setting "Delete on close" flag for an open
 * file.  In this way the file will be deleted after
 * last close. This flag can be set by SmbTrans2SetFileInfo
 * with FILE_DISPOSITION_INFO information level.
 * For setting this flag, the file should be opened by
 * DELETE access in the FID that is passed in the Trans2
 * request.
 */

uint32_t
smb_ofile_delete_check(smb_ofile_t *of)
{
	ASSERT(of->f_magic == SMB_OFILE_MAGIC);

	mutex_enter(&of->f_mutex);

	if (of->f_state != SMB_OFILE_STATE_OPEN) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_INVALID_HANDLE);
	}

	if (of->f_granted_access &
	    (FILE_READ_DATA | FILE_WRITE_DATA |
	    FILE_APPEND_DATA | FILE_EXECUTE | DELETE)) {
		mutex_exit(&of->f_mutex);
		return (NT_STATUS_SHARING_VIOLATION);
	}

	mutex_exit(&of->f_mutex);
	return (NT_STATUS_SUCCESS);
}

cred_t *
smb_ofile_getcred(smb_ofile_t *of)
{
	return (of->f_cr);
}

/*
 * smb_ofile_set_delete_on_close
 *
 * Set the DeleteOnClose flag on the smb file. When the file is closed,
 * the flag will be transferred to the smb node, which will commit the
 * delete operation and inhibit subsequent open requests.
 *
 * When DeleteOnClose is set on an smb_node, the common open code will
 * reject subsequent open requests for the file. Observation of Windows
 * 2000 indicates that subsequent opens should be allowed (assuming
 * there would be no sharing violation) until the file is closed using
 * the fid on which the DeleteOnClose was requested.
 */
void
smb_ofile_set_delete_on_close(smb_ofile_t *of)
{
	mutex_enter(&of->f_mutex);
	of->f_flags |= SMB_OFLAGS_SET_DELETE_ON_CLOSE;
	mutex_exit(&of->f_mutex);
}

/*
 * Encode open file information into a buffer; needed in user space to
 * support RPC requests.
 */
static int
smb_ofile_netinfo_encode(smb_ofile_t *of, uint8_t *buf, size_t buflen,
    uint32_t *nbytes)
{
	smb_netfileinfo_t	fi;
	int			rc;

	rc = smb_ofile_netinfo_init(of, &fi);
	if (rc == 0) {
		rc = smb_netfileinfo_encode(&fi, buf, buflen, nbytes);
		smb_ofile_netinfo_fini(&fi);
	}

	return (rc);
}

static int
smb_ofile_netinfo_init(smb_ofile_t *of, smb_netfileinfo_t *fi)
{
	smb_user_t	*user;
	smb_tree_t	*tree;
	smb_node_t	*node;
	char		*path;
	char		*buf;
	int		rc;

	ASSERT(of);
	user = of->f_user;
	tree = of->f_tree;
	ASSERT(user);
	ASSERT(tree);

	buf = kmem_zalloc(MAXPATHLEN, KM_SLEEP);

	switch (of->f_ftype) {
	case SMB_FTYPE_DISK:
		node = of->f_node;
		ASSERT(node);

		fi->fi_permissions = of->f_granted_access;
		fi->fi_numlocks = smb_lock_get_lock_count(node, of);

		path = kmem_zalloc(MAXPATHLEN, KM_SLEEP);

		if (node != tree->t_snode) {
			rc = smb_node_getshrpath(node, tree, path, MAXPATHLEN);
			if (rc != 0)
				(void) strlcpy(path, node->od_name, MAXPATHLEN);
		}

		(void) snprintf(buf, MAXPATHLEN, "%s:%s", tree->t_sharename,
		    path);
		kmem_free(path, MAXPATHLEN);
		break;

	case SMB_FTYPE_MESG_PIPE:
		ASSERT(of->f_pipe);

		fi->fi_permissions = FILE_READ_DATA | FILE_WRITE_DATA |
		    FILE_EXECUTE;
		fi->fi_numlocks = 0;
		(void) snprintf(buf, MAXPATHLEN, "\\PIPE\\%s",
		    of->f_pipe->p_name);
		break;

	default:
		kmem_free(buf, MAXPATHLEN);
		return (-1);
	}

	fi->fi_fid = of->f_fid;
	fi->fi_uniqid = of->f_uniqid;
	fi->fi_pathlen = strlen(buf) + 1;
	fi->fi_path = smb_mem_strdup(buf);
	kmem_free(buf, MAXPATHLEN);

	fi->fi_namelen = user->u_domain_len + user->u_name_len + 2;
	fi->fi_username = kmem_alloc(fi->fi_namelen, KM_SLEEP);
	(void) snprintf(fi->fi_username, fi->fi_namelen, "%s\\%s",
	    user->u_domain, user->u_name);
	return (0);
}

static void
smb_ofile_netinfo_fini(smb_netfileinfo_t *fi)
{
	if (fi == NULL)
		return;

	if (fi->fi_path)
		smb_mem_free(fi->fi_path);
	if (fi->fi_username)
		kmem_free(fi->fi_username, fi->fi_namelen);

	bzero(fi, sizeof (smb_netfileinfo_t));
}

/*
 * A query of user and group quotas may span multiple requests.
 * f_quota_resume is used to determine where the query should
 * be resumed, in a subsequent request. f_quota_resume contains
 * the SID of the last quota entry returned to the client.
 */
void
smb_ofile_set_quota_resume(smb_ofile_t *ofile, char *resume)
{
	ASSERT(ofile);
	mutex_enter(&ofile->f_mutex);
	if (resume == NULL)
		bzero(ofile->f_quota_resume, SMB_SID_STRSZ);
	else
		(void) strlcpy(ofile->f_quota_resume, resume, SMB_SID_STRSZ);
	mutex_exit(&ofile->f_mutex);
}

void
smb_ofile_get_quota_resume(smb_ofile_t *ofile, char *buf, int bufsize)
{
	ASSERT(ofile);
	mutex_enter(&ofile->f_mutex);
	(void) strlcpy(buf, ofile->f_quota_resume, bufsize);
	mutex_exit(&ofile->f_mutex);
}