first public release of samba4 code

(This used to be commit b0510b5428b3461aeb9bbe3cc95f62fc73e2b97f)

1 files changed, 849 insertions, 0 deletions

diff --git a/source4/locking/locking.c b/source4/locking/locking.c
new file mode 100644
index 0000000000..63e1f3a164
--- /dev/null
+++ b/source4/locking/locking.c
@@ -0,0 +1,849 @@
+/* 
+   Unix SMB/CIFS implementation.
+   Locking functions
+   Copyright (C) Andrew Tridgell 1992-2000
+   Copyright (C) Jeremy Allison 1992-2000
+   
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+   Revision History:
+
+   12 aug 96: Erik.Devriendt@te6.siemens.be
+   added support for shared memory implementation of share mode locking
+
+   May 1997. Jeremy Allison (jallison@whistle.com). Modified share mode
+   locking to deal with multiple share modes per open file.
+
+   September 1997. Jeremy Allison (jallison@whistle.com). Added oplock
+   support.
+
+   rewrtten completely to use new tdb code. Tridge, Dec '99
+
+   Added POSIX locking support. Jeremy Allison (jeremy@valinux.com), Apr. 2000.
+*/
+
+#include "includes.h"
+
+/* the locking database handle */
+static TDB_CONTEXT *tdb;
+
+/****************************************************************************
+ Debugging aid :-).
+****************************************************************************/
+
+static const char *lock_type_name(enum brl_type lock_type)
+{
+	return (lock_type == READ_LOCK) ? "READ" : "WRITE";
+}
+
+/****************************************************************************
+ Utility function called to see if a file region is locked.
+ If check_self is True, then checks on our own fd with the same locking context
+ are still made. If check_self is False, then checks are not made on our own fd
+ with the same locking context are not made.
+****************************************************************************/
+
+BOOL is_locked(files_struct *fsp,struct tcon_context *conn,
+	       SMB_BIG_UINT count,SMB_BIG_UINT offset, 
+	       enum brl_type lock_type, BOOL check_self)
+{
+	int snum = SNUM(conn);
+	BOOL ret;
+	
+	if (count == 0)
+		return(False);
+
+	if (!lp_locking(snum) || !lp_strict_locking(snum))
+		return(False);
+
+	ret = !brl_locktest(fsp->dev, fsp->inode, fsp->fnum,
+			    global_smbpid, sys_getpid(), conn->cnum, 
+			    offset, count, lock_type, check_self);
+
+	DEBUG(10,("is_locked: brl start=%.0f len=%.0f %s for file %s\n",
+			(double)offset, (double)count, ret ? "locked" : "unlocked",
+			fsp->fsp_name ));
+
+	/*
+	 * There is no lock held by an SMB daemon, check to
+	 * see if there is a POSIX lock from a UNIX or NFS process.
+	 */
+
+	if(!ret && lp_posix_locking(snum)) {
+		ret = is_posix_locked(fsp, offset, count, lock_type);
+
+		DEBUG(10,("is_locked: posix start=%.0f len=%.0f %s for file %s\n",
+				(double)offset, (double)count, ret ? "locked" : "unlocked",
+				fsp->fsp_name ));
+	}
+
+	return ret;
+}
+
+/****************************************************************************
+ Utility function called by locking requests.
+****************************************************************************/
+
+static NTSTATUS do_lock(files_struct *fsp,struct tcon_context *conn, uint16 lock_pid,
+		 SMB_BIG_UINT count,SMB_BIG_UINT offset,enum brl_type lock_type)
+{
+	NTSTATUS status = NT_STATUS_LOCK_NOT_GRANTED;
+
+	if (!lp_locking(SNUM(conn)))
+		return NT_STATUS_OK;
+
+	/* NOTE! 0 byte long ranges ARE allowed and should be stored  */
+
+	DEBUG(10,("do_lock: lock type %s start=%.0f len=%.0f requested for file %s\n",
+		  lock_type_name(lock_type), (double)offset, (double)count, fsp->fsp_name ));
+
+	if (OPEN_FSP(fsp) && fsp->can_lock && (fsp->conn == conn)) {
+		status = brl_lock(fsp->dev, fsp->inode, fsp->fnum,
+				  lock_pid, sys_getpid(), conn->cnum, 
+				  offset, count, 
+				  lock_type);
+
+		if (NT_STATUS_IS_OK(status) && lp_posix_locking(SNUM(conn))) {
+
+			/*
+			 * Try and get a POSIX lock on this range.
+			 * Note that this is ok if it is a read lock
+			 * overlapping on a different fd. JRA.
+			 */
+
+			if (!set_posix_lock(fsp, offset, count, lock_type)) {
+				status = NT_STATUS_LOCK_NOT_GRANTED;
+				/*
+				 * We failed to map - we must now remove the brl
+				 * lock entry.
+				 */
+				(void)brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
+								lock_pid, sys_getpid(), conn->cnum, 
+								offset, count, False);
+			}
+		}
+	}
+
+	return status;
+}
+
+/****************************************************************************
+ Utility function called by locking requests. This is *DISGUSTING*. It also
+ appears to be "What Windows Does" (tm). Andrew, ever wonder why Windows 2000
+ is so slow on the locking tests...... ? This is the reason. Much though I hate
+ it, we need this. JRA.
+****************************************************************************/
+
+NTSTATUS do_lock_spin(files_struct *fsp,struct tcon_context *conn, uint16 lock_pid,
+		 SMB_BIG_UINT count,SMB_BIG_UINT offset,enum brl_type lock_type)
+{
+	int j, maxj = lp_lock_spin_count();
+	int sleeptime = lp_lock_sleep_time();
+	NTSTATUS status, ret;
+
+	if (maxj <= 0)
+		maxj = 1;
+
+	ret = NT_STATUS_OK; /* to keep dumb compilers happy */
+
+	for (j = 0; j < maxj; j++) {
+		status = do_lock(fsp, conn, lock_pid, count, offset, lock_type);
+		if (!NT_STATUS_EQUAL(status, NT_STATUS_LOCK_NOT_GRANTED) &&
+		    !NT_STATUS_EQUAL(status, NT_STATUS_FILE_LOCK_CONFLICT)) {
+			return status;
+		}
+		/* if we do fail then return the first error code we got */
+		if (j == 0) {
+			ret = status;
+		}
+		if (sleeptime)
+			sys_usleep(sleeptime);
+	}
+	return ret;
+}
+
+/****************************************************************************
+ Utility function called by unlocking requests.
+****************************************************************************/
+
+NTSTATUS do_unlock(files_struct *fsp,struct tcon_context *conn, uint16 lock_pid,
+		   SMB_BIG_UINT count,SMB_BIG_UINT offset)
+{
+	BOOL ok = False;
+	
+	if (!lp_locking(SNUM(conn)))
+		return NT_STATUS_OK;
+	
+	if (!OPEN_FSP(fsp) || !fsp->can_lock || (fsp->conn != conn)) {
+		return NT_STATUS_INVALID_HANDLE;
+	}
+	
+	DEBUG(10,("do_unlock: unlock start=%.0f len=%.0f requested for file %s\n",
+		  (double)offset, (double)count, fsp->fsp_name ));
+
+	/*
+	 * Remove the existing lock record from the tdb lockdb
+	 * before looking at POSIX locks. If this record doesn't
+	 * match then don't bother looking to remove POSIX locks.
+	 */
+
+	ok = brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
+			lock_pid, sys_getpid(), conn->cnum, offset, count, False);
+   
+	if (!ok) {
+		DEBUG(10,("do_unlock: returning ERRlock.\n" ));
+		return NT_STATUS_RANGE_NOT_LOCKED;
+	}
+
+	if (!lp_posix_locking(SNUM(conn)))
+		return NT_STATUS_OK;
+
+	(void)release_posix_lock(fsp, offset, count);
+
+	return NT_STATUS_OK;
+}
+
+/****************************************************************************
+ Remove any locks on this fd. Called from file_close().
+****************************************************************************/
+
+void locking_close_file(files_struct *fsp)
+{
+	pid_t pid = sys_getpid();
+
+	if (!lp_locking(SNUM(fsp->conn)))
+		return;
+
+	/*
+	 * Just release all the brl locks, no need to release individually.
+	 */
+
+	brl_close(fsp->dev, fsp->inode, pid, fsp->conn->cnum, fsp->fnum);
+
+	if(lp_posix_locking(SNUM(fsp->conn))) {
+
+	 	/* 
+		 * Release all the POSIX locks.
+		 */
+		posix_locking_close_file(fsp);
+
+	}
+}
+
+/****************************************************************************
+ Initialise the locking functions.
+****************************************************************************/
+
+static int open_read_only;
+
+BOOL locking_init(int read_only)
+{
+	brl_init(read_only);
+
+	if (tdb)
+		return True;
+
+	tdb = tdb_open_log(lock_path("locking.tdb"), 
+		       0, TDB_DEFAULT|(read_only?0x0:TDB_CLEAR_IF_FIRST), 
+		       read_only?O_RDONLY:O_RDWR|O_CREAT,
+		       0644);
+
+	if (!tdb) {
+		DEBUG(0,("ERROR: Failed to initialise locking database\n"));
+		return False;
+	}
+	
+	if (!posix_locking_init(read_only))
+		return False;
+
+	open_read_only = read_only;
+
+	return True;
+}
+
+/*******************************************************************
+ Deinitialize the share_mode management.
+******************************************************************/
+
+BOOL locking_end(void)
+{
+
+	brl_shutdown(open_read_only);
+	if (tdb) {
+
+		if (tdb_close(tdb) != 0)
+			return False;
+	}
+
+	return True;
+}
+
+/*******************************************************************
+ Form a static locking key for a dev/inode pair.
+******************************************************************/
+
+static TDB_DATA locking_key(SMB_DEV_T dev, SMB_INO_T inode)
+{
+	static struct locking_key key;
+	TDB_DATA kbuf;
+
+	memset(&key, '\0', sizeof(key));
+	key.dev = dev;
+	key.inode = inode;
+	kbuf.dptr = (char *)&key;
+	kbuf.dsize = sizeof(key);
+	return kbuf;
+}
+
+static TDB_DATA locking_key_fsp(files_struct *fsp)
+{
+	return locking_key(fsp->dev, fsp->inode);
+}
+
+/*******************************************************************
+ Lock a hash bucket entry.
+******************************************************************/
+
+BOOL lock_share_entry(struct tcon_context *conn,
+		      SMB_DEV_T dev, SMB_INO_T inode)
+{
+	return tdb_chainlock(tdb, locking_key(dev, inode)) == 0;
+}
+
+/*******************************************************************
+ Unlock a hash bucket entry.
+******************************************************************/
+
+void unlock_share_entry(struct tcon_context *conn,
+			SMB_DEV_T dev, SMB_INO_T inode)
+{
+	tdb_chainunlock(tdb, locking_key(dev, inode));
+}
+
+/*******************************************************************
+ Lock a hash bucket entry. use a fsp for convenience
+******************************************************************/
+
+BOOL lock_share_entry_fsp(files_struct *fsp)
+{
+	return tdb_chainlock(tdb, locking_key(fsp->dev, fsp->inode)) == 0;
+}
+
+/*******************************************************************
+ Unlock a hash bucket entry.
+******************************************************************/
+
+void unlock_share_entry_fsp(files_struct *fsp)
+{
+	tdb_chainunlock(tdb, locking_key(fsp->dev, fsp->inode));
+}
+
+/*******************************************************************
+ Print out a share mode.
+********************************************************************/
+
+static char *share_mode_str(int num, share_mode_entry *e)
+{
+	static pstring share_str;
+
+	slprintf(share_str, sizeof(share_str)-1, "share_mode_entry[%d]: \
+pid = %u, share_mode = 0x%x, desired_access = 0x%x, port = 0x%x, type= 0x%x, file_id = %lu, dev = 0x%x, inode = %.0f",
+	num, e->pid, e->share_mode, (unsigned int)e->desired_access, e->op_port, e->op_type, e->share_file_id,
+	(unsigned int)e->dev, (double)e->inode );
+
+	return share_str;
+}
+
+/*******************************************************************
+ Print out a share mode table.
+********************************************************************/
+
+static void print_share_mode_table(struct locking_data *data)
+{
+	int num_share_modes = data->u.num_share_mode_entries;
+	share_mode_entry *shares = (share_mode_entry *)(data + 1);
+	int i;
+
+	for (i = 0; i < num_share_modes; i++) {
+		share_mode_entry *entry_p = &shares[i];
+		DEBUG(10,("print_share_mode_table: %s\n", share_mode_str(i, entry_p) ));
+	}
+}
+
+/*******************************************************************
+ Get all share mode entries for a dev/inode pair.
+********************************************************************/
+
+int get_share_modes(struct tcon_context *conn, 
+		    SMB_DEV_T dev, SMB_INO_T inode, 
+		    share_mode_entry **pp_shares)
+{
+	TDB_DATA dbuf;
+	struct locking_data *data;
+	int num_share_modes;
+	share_mode_entry *shares = NULL;
+
+	*pp_shares = NULL;
+
+	dbuf = tdb_fetch(tdb, locking_key(dev, inode));
+	if (!dbuf.dptr)
+		return 0;
+
+	data = (struct locking_data *)dbuf.dptr;
+	num_share_modes = data->u.num_share_mode_entries;
+	if(num_share_modes) {
+		int i;
+		int del_count = 0;
+
+		shares = (share_mode_entry *)memdup(dbuf.dptr + sizeof(*data),	
+						num_share_modes * sizeof(share_mode_entry));
+
+		if (!shares) {
+			SAFE_FREE(dbuf.dptr);
+			return 0;
+		}
+
+		/*
+		 * Ensure that each entry has a real process attached.
+		 */
+
+		for (i = 0; i < num_share_modes; ) {
+			share_mode_entry *entry_p = &shares[i];
+			if (process_exists(entry_p->pid)) {
+				DEBUG(10,("get_share_modes: %s\n", share_mode_str(i, entry_p) ));
+				i++;
+			} else {
+				DEBUG(10,("get_share_modes: deleted %s\n", share_mode_str(i, entry_p) ));
+				memcpy( &shares[i], &shares[i+1],
+					sizeof(share_mode_entry) * (num_share_modes - i - 1));
+				num_share_modes--;
+				del_count++;
+			}
+		}
+
+		/* Did we delete any ? If so, re-store in tdb. */
+		if (del_count) {
+			data->u.num_share_mode_entries = num_share_modes;
+			
+			if (num_share_modes)
+				memcpy(dbuf.dptr + sizeof(*data), shares,
+						num_share_modes * sizeof(share_mode_entry));
+
+			/* The record has shrunk a bit */
+			dbuf.dsize -= del_count * sizeof(share_mode_entry);
+
+			if (tdb_store(tdb, locking_key(dev, inode), dbuf, TDB_REPLACE) == -1) {
+				SAFE_FREE(shares);
+				SAFE_FREE(dbuf.dptr);
+				return 0;
+			}
+		}
+	}
+
+	SAFE_FREE(dbuf.dptr);
+	*pp_shares = shares;
+	return num_share_modes;
+}
+
+/*******************************************************************
+ Fill a share mode entry.
+********************************************************************/
+
+static void fill_share_mode(char *p, files_struct *fsp, uint16 port, uint16 op_type)
+{
+	share_mode_entry *e = (share_mode_entry *)p;
+	void *x = &e->time; /* Needed to force alignment. p may not be aligned.... */
+
+	memset(e, '\0', sizeof(share_mode_entry));
+	e->pid = sys_getpid();
+	e->share_mode = fsp->share_mode;
+	e->desired_access = fsp->desired_access;
+	e->op_port = port;
+	e->op_type = op_type;
+	memcpy(x, &fsp->open_time, sizeof(struct timeval));
+	e->share_file_id = fsp->file_id;
+	e->dev = fsp->dev;
+	e->inode = fsp->inode;
+}
+
+/*******************************************************************
+ Check if two share mode entries are identical, ignoring oplock 
+ and port info and desired_access.
+********************************************************************/
+
+BOOL share_modes_identical( share_mode_entry *e1, share_mode_entry *e2)
+{
+#if 1 /* JRA PARANOIA TEST - REMOVE LATER */
+	if (e1->pid == e2->pid &&
+		e1->share_file_id == e2->share_file_id &&
+		e1->dev == e2->dev &&
+		e1->inode == e2->inode &&
+		(e1->share_mode & ~DELETE_ON_CLOSE_FLAG) != (e2->share_mode & ~DELETE_ON_CLOSE_FLAG)) {
+			DEBUG(0,("PANIC: share_modes_identical: share_mode missmatch (e1 = %u, e2 = %u). Logic error.\n",
+				(unsigned int)(e1->share_mode & ~DELETE_ON_CLOSE_FLAG),
+				(unsigned int)(e2->share_mode & ~DELETE_ON_CLOSE_FLAG) ));
+		smb_panic("PANIC: share_modes_identical logic error.\n");
+	}
+#endif
+
+	return (e1->pid == e2->pid &&
+		(e1->share_mode & ~DELETE_ON_CLOSE_FLAG) == (e2->share_mode & ~DELETE_ON_CLOSE_FLAG) &&
+		e1->dev == e2->dev &&
+		e1->inode == e2->inode &&
+		e1->share_file_id == e2->share_file_id );
+}
+
+/*******************************************************************
+ Delete a specific share mode. Return the number
+ of entries left, and a memdup'ed copy of the entry deleted (if required).
+ Ignore if no entry deleted.
+********************************************************************/
+
+ssize_t del_share_entry( SMB_DEV_T dev, SMB_INO_T inode,
+			share_mode_entry *entry, share_mode_entry **ppse)
+{
+	TDB_DATA dbuf;
+	struct locking_data *data;
+	int i, del_count=0;
+	share_mode_entry *shares;
+	ssize_t count = 0;
+
+	if (ppse)
+		*ppse = NULL;
+
+	/* read in the existing share modes */
+	dbuf = tdb_fetch(tdb, locking_key(dev, inode));
+	if (!dbuf.dptr)
+		return -1;
+
+	data = (struct locking_data *)dbuf.dptr;
+	shares = (share_mode_entry *)(dbuf.dptr + sizeof(*data));
+
+	/*
+	 * Find any with this pid and delete it
+	 * by overwriting with the rest of the data 
+	 * from the record.
+	 */
+
+	DEBUG(10,("del_share_entry: num_share_modes = %d\n", data->u.num_share_mode_entries ));
+
+	for (i=0;i<data->u.num_share_mode_entries;) {
+		if (share_modes_identical(&shares[i], entry)) {
+			DEBUG(10,("del_share_entry: deleted %s\n",
+				share_mode_str(i, &shares[i]) ));
+			if (ppse)
+				*ppse = memdup(&shares[i], sizeof(*shares));
+			data->u.num_share_mode_entries--;
+			memmove(&shares[i], &shares[i+1], 
+				dbuf.dsize - (sizeof(*data) + (i+1)*sizeof(*shares)));
+			del_count++;
+
+			DEBUG(10,("del_share_entry: deleting entry %d\n", i ));
+
+		} else {
+			i++;
+		}
+	}
+
+	if (del_count) {
+		/* the record may have shrunk a bit */
+		dbuf.dsize -= del_count * sizeof(*shares);
+
+		count = (ssize_t)data->u.num_share_mode_entries;
+
+		/* store it back in the database */
+		if (data->u.num_share_mode_entries == 0) {
+			if (tdb_delete(tdb, locking_key(dev, inode)) == -1)
+				count = -1;
+		} else {
+			if (tdb_store(tdb, locking_key(dev, inode), dbuf, TDB_REPLACE) == -1)
+				count = -1;
+		}
+	}
+	DEBUG(10,("del_share_entry: Remaining table.\n"));
+	print_share_mode_table((struct locking_data *)dbuf.dptr);
+	SAFE_FREE(dbuf.dptr);
+	return count;
+}
+
+/*******************************************************************
+ Del the share mode of a file for this process. Return the number
+ of entries left, and a memdup'ed copy of the entry deleted.
+********************************************************************/
+
+ssize_t del_share_mode(files_struct *fsp, share_mode_entry **ppse)
+{
+	share_mode_entry entry;
+
+	/*
+	 * Fake up a share_mode_entry for comparisons.
+	 */
+
+	fill_share_mode((char *)&entry, fsp, 0, 0);
+	return del_share_entry(fsp->dev, fsp->inode, &entry, ppse);
+}
+
+/*******************************************************************
+ Set the share mode of a file. Return False on fail, True on success.
+********************************************************************/
+
+BOOL set_share_mode(files_struct *fsp, uint16 port, uint16 op_type)
+{
+	TDB_DATA dbuf;
+	struct locking_data *data;
+	char *p=NULL;
+	int size;
+	BOOL ret = True;
+		
+	/* read in the existing share modes if any */
+	dbuf = tdb_fetch(tdb, locking_key_fsp(fsp));
+	if (!dbuf.dptr) {
+		size_t offset;
+		/* we'll need to create a new record */
+		pstring fname;
+
+		pstrcpy(fname, fsp->conn->connectpath);
+		pstrcat(fname, "/");
+		pstrcat(fname, fsp->fsp_name);
+
+		size = sizeof(*data) + sizeof(share_mode_entry) + strlen(fname) + 1;
+		p = (char *)malloc(size);
+		if (!p)
+			return False;
+		data = (struct locking_data *)p;
+		data->u.num_share_mode_entries = 1;
+	
+		DEBUG(10,("set_share_mode: creating entry for file %s. num_share_modes = 1\n",
+			fsp->fsp_name ));
+
+		offset = sizeof(*data) + sizeof(share_mode_entry);
+		safe_strcpy(p + offset, fname, size - offset - 1);
+		fill_share_mode(p + sizeof(*data), fsp, port, op_type);
+		dbuf.dptr = p;
+		dbuf.dsize = size;
+		if (tdb_store(tdb, locking_key_fsp(fsp), dbuf, TDB_REPLACE) == -1)
+			ret = False;
+
+		print_share_mode_table((struct locking_data *)p);
+
+		SAFE_FREE(p);
+		return ret;
+	}
+
+	/* we're adding to an existing entry - this is a bit fiddly */
+	data = (struct locking_data *)dbuf.dptr;
+
+	data->u.num_share_mode_entries++;
+	
+	DEBUG(10,("set_share_mode: adding entry for file %s. new num_share_modes = %d\n",
+		fsp->fsp_name, data->u.num_share_mode_entries ));
+
+	size = dbuf.dsize + sizeof(share_mode_entry);
+	p = malloc(size);
+	if (!p) {
+		SAFE_FREE(dbuf.dptr);
+		return False;
+	}
+	memcpy(p, dbuf.dptr, sizeof(*data));
+	fill_share_mode(p + sizeof(*data), fsp, port, op_type);
+	memcpy(p + sizeof(*data) + sizeof(share_mode_entry), dbuf.dptr + sizeof(*data),
+	       dbuf.dsize - sizeof(*data));
+	SAFE_FREE(dbuf.dptr);
+	dbuf.dptr = p;
+	dbuf.dsize = size;
+	if (tdb_store(tdb, locking_key_fsp(fsp), dbuf, TDB_REPLACE) == -1)
+		ret = False;
+	print_share_mode_table((struct locking_data *)p);
+	SAFE_FREE(p);
+	return ret;
+}
+
+/*******************************************************************
+ A generic in-place modification call for share mode entries.
+********************************************************************/
+
+static BOOL mod_share_mode( SMB_DEV_T dev, SMB_INO_T inode, share_mode_entry *entry,
+			   void (*mod_fn)(share_mode_entry *, SMB_DEV_T, SMB_INO_T, void *),
+			   void *param)
+{
+	TDB_DATA dbuf;
+	struct locking_data *data;
+	int i;
+	share_mode_entry *shares;
+	BOOL need_store=False;
+	BOOL ret = True;
+
+	/* read in the existing share modes */
+	dbuf = tdb_fetch(tdb, locking_key(dev, inode));
+	if (!dbuf.dptr)
+		return False;
+
+	data = (struct locking_data *)dbuf.dptr;
+	shares = (share_mode_entry *)(dbuf.dptr + sizeof(*data));
+
+	/* find any with our pid and call the supplied function */
+	for (i=0;i<data->u.num_share_mode_entries;i++) {
+		if (share_modes_identical(entry, &shares[i])) {
+			mod_fn(&shares[i], dev, inode, param);
+			need_store=True;
+		}
+	}
+
+	/* if the mod fn was called then store it back */
+	if (need_store) {
+		if (data->u.num_share_mode_entries == 0) {
+			if (tdb_delete(tdb, locking_key(dev, inode)) == -1)
+				ret = False;
+		} else {
+			if (tdb_store(tdb, locking_key(dev, inode), dbuf, TDB_REPLACE) == -1)
+				ret = False;
+		}
+	}
+
+	SAFE_FREE(dbuf.dptr);
+	return ret;
+}
+
+/*******************************************************************
+ Static function that actually does the work for the generic function
+ below.
+********************************************************************/
+
+static void remove_share_oplock_fn(share_mode_entry *entry, SMB_DEV_T dev, SMB_INO_T inode, 
+                                   void *param)
+{
+	DEBUG(10,("remove_share_oplock_fn: removing oplock info for entry dev=%x ino=%.0f\n",
+		  (unsigned int)dev, (double)inode ));
+	/* Delete the oplock info. */
+	entry->op_port = 0;
+	entry->op_type = NO_OPLOCK;
+}
+
+/*******************************************************************
+ Remove an oplock port and mode entry from a share mode.
+********************************************************************/
+
+BOOL remove_share_oplock(files_struct *fsp)
+{
+	share_mode_entry entry;
+	/*
+	 * Fake up an entry for comparisons...
+	 */
+	fill_share_mode((char *)&entry, fsp, 0, 0);
+	return mod_share_mode(fsp->dev, fsp->inode, &entry, remove_share_oplock_fn, NULL);
+}
+
+/*******************************************************************
+ Static function that actually does the work for the generic function
+ below.
+********************************************************************/
+
+static void downgrade_share_oplock_fn(share_mode_entry *entry, SMB_DEV_T dev, SMB_INO_T inode, 
+                                   void *param)
+{
+	DEBUG(10,("downgrade_share_oplock_fn: downgrading oplock info for entry dev=%x ino=%.0f\n",
+		  (unsigned int)dev, (double)inode ));
+	entry->op_type = LEVEL_II_OPLOCK;
+}
+
+/*******************************************************************
+ Downgrade a oplock type from exclusive to level II.
+********************************************************************/
+
+BOOL downgrade_share_oplock(files_struct *fsp)
+{
+	share_mode_entry entry;
+	/*
+	 * Fake up an entry for comparisons...
+	 */
+	fill_share_mode((char *)&entry, fsp, 0, 0);
+	return mod_share_mode(fsp->dev, fsp->inode, &entry, downgrade_share_oplock_fn, NULL);
+}
+
+/*******************************************************************
+ Get/Set the delete on close flag in a set of share modes.
+ Return False on fail, True on success.
+********************************************************************/
+
+BOOL modify_delete_flag( SMB_DEV_T dev, SMB_INO_T inode, BOOL delete_on_close)
+{
+	TDB_DATA dbuf;
+	struct locking_data *data;
+	int i;
+	share_mode_entry *shares;
+
+	/* read in the existing share modes */
+	dbuf = tdb_fetch(tdb, locking_key(dev, inode));
+	if (!dbuf.dptr)
+		return False;
+
+	data = (struct locking_data *)dbuf.dptr;
+	shares = (share_mode_entry *)(dbuf.dptr + sizeof(*data));
+
+	/* Set/Unset the delete on close element. */
+	for (i=0;i<data->u.num_share_mode_entries;i++,shares++) {
+		shares->share_mode = (delete_on_close ?
+                            (shares->share_mode | DELETE_ON_CLOSE_FLAG) :
+                            (shares->share_mode & ~DELETE_ON_CLOSE_FLAG) );
+	}
+
+	/* store it back */
+	if (data->u.num_share_mode_entries) {
+		if (tdb_store(tdb, locking_key(dev,inode), dbuf, TDB_REPLACE)==-1) {
+			SAFE_FREE(dbuf.dptr);
+			return False;
+		}
+	}
+
+	SAFE_FREE(dbuf.dptr);
+	return True;
+}
+
+/****************************************************************************
+ Traverse the whole database with this function, calling traverse_callback
+ on each share mode
+****************************************************************************/
+
+static int traverse_fn(TDB_CONTEXT *the_tdb, TDB_DATA kbuf, TDB_DATA dbuf, 
+                       void* state)
+{
+	struct locking_data *data;
+	share_mode_entry *shares;
+	char *name;
+	int i;
+
+	SHAREMODE_FN(traverse_callback) = (SHAREMODE_FN_CAST())state;
+
+	data = (struct locking_data *)dbuf.dptr;
+	shares = (share_mode_entry *)(dbuf.dptr + sizeof(*data));
+	name = dbuf.dptr + sizeof(*data) + data->u.num_share_mode_entries*sizeof(*shares);
+
+	for (i=0;i<data->u.num_share_mode_entries;i++) {
+		traverse_callback(&shares[i], name);
+	}
+	return 0;
+}
+
+/*******************************************************************
+ Call the specified function on each entry under management by the
+ share mode system.
+********************************************************************/
+
+int share_mode_forall(SHAREMODE_FN(fn))
+{
+	if (!tdb)
+		return 0;
+	return tdb_traverse(tdb, traverse_fn, (void*)fn);
+}