r2565: syncing up for 3.0.8pre1

[Samba.git] / source / locking / locking.c

/* 
   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"
uint16 global_smbpid;

/* the locking database handle */
static TDB_CONTEXT *tdb;

struct locking_data {
        union {
                int num_share_mode_entries;
                share_mode_entry dummy; /* Needed for alignment. */
        } u;
        /* the following two entries are implicit
           share_mode_entry modes[num_share_mode_entries];
           char file_name[];
        */
};

/****************************************************************************
 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,connection_struct *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,connection_struct *conn, uint16 lock_pid,
                 SMB_BIG_UINT count,SMB_BIG_UINT offset,enum brl_type lock_type, BOOL *my_lock_ctx)
{
        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, my_lock_ctx);

                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)) {
                                if (errno == EACCES || errno == EAGAIN)
                                        status = NT_STATUS_FILE_LOCK_CONFLICT;
                                else
                                        status = map_nt_error_from_unix(errno);

                                /*
                                 * 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,
                                                                NULL, NULL);
                        }
                }
        }

        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,connection_struct *conn, uint16 lock_pid,
                 SMB_BIG_UINT count,SMB_BIG_UINT offset,enum brl_type lock_type, BOOL *my_lock_ctx)
{
        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, my_lock_ctx);
                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;
                        /* Don't spin if we blocked ourselves. */
                        if (*my_lock_ctx)
                                return ret;
                }
                if (sleeptime)
                        sys_usleep(sleeptime);
        }
        return ret;
}

/* Struct passed to brl_unlock. */
struct posix_unlock_data_struct {
        files_struct *fsp;
        SMB_BIG_UINT offset;
        SMB_BIG_UINT count;
};

/****************************************************************************
 Function passed to brl_unlock to allow POSIX unlock to be done first.
****************************************************************************/

static void posix_unlock(void *pre_data)
{
        struct posix_unlock_data_struct *pdata = (struct posix_unlock_data_struct *)pre_data;

        if (lp_posix_locking(SNUM(pdata->fsp->conn)))
                release_posix_lock(pdata->fsp, pdata->offset, pdata->count);
}

/****************************************************************************
 Utility function called by unlocking requests.
****************************************************************************/

NTSTATUS do_unlock(files_struct *fsp,connection_struct *conn, uint16 lock_pid,
                   SMB_BIG_UINT count,SMB_BIG_UINT offset)
{
        BOOL ok = False;
        struct posix_unlock_data_struct posix_data;
        
        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.
         */

        posix_data.fsp = fsp;
        posix_data.offset = offset;
        posix_data.count = count;

        ok = brl_unlock(fsp->dev, fsp->inode, fsp->fnum,
                        lock_pid, sys_getpid(), conn->cnum, offset, count,
                        False, posix_unlock, (void *)&posix_data);
   
        if (!ok) {
                DEBUG(10,("do_unlock: returning ERRlock.\n" ));
                return NT_STATUS_RANGE_NOT_LOCKED;
        }
        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(connection_struct *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(connection_struct *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.
********************************************************************/

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 = %lu, share_mode = 0x%x, desired_access = 0x%x, port = 0x%x, type= 0x%x, file_id = %lu, dev = 0x%x, inode = %.0f",
        num, (unsigned long)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(connection_struct *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;
        TDB_DATA key = locking_key(dev, inode);
        *pp_shares = NULL;

        dbuf = tdb_fetch(tdb, key);
        if (!dbuf.dptr)
                return 0;

        data = (struct locking_data *)dbuf.dptr;
        num_share_modes = data->u.num_share_mode_entries;
        if(num_share_modes) {
                pstring fname;
                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;
                }

                /* Save off the associated filename. */
                pstrcpy(fname, dbuf.dptr + sizeof(*data) + num_share_modes * sizeof(share_mode_entry));

                /*
                 * 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) ));
                                if (num_share_modes - i - 1 > 0) {
                                        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));
                                /* Append the filename. */
                                pstrcpy(dbuf.dptr + sizeof(*data) + num_share_modes * sizeof(share_mode_entry), fname);
                        }

                        /* The record has shrunk a bit */
                        dbuf.dsize -= del_count * sizeof(share_mode_entry);

                        if (data->u.num_share_mode_entries == 0) {
                                if (tdb_delete(tdb, key) == -1) {
                                        SAFE_FREE(shares);
                                        SAFE_FREE(dbuf.dptr);
                                        return 0;
                                }
                        } else {
                                if (tdb_store(tdb, key, 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;
        TDB_DATA key = locking_key(dev, inode);

        if (ppse)
                *ppse = NULL;

        /* read in the existing share modes */
        dbuf = tdb_fetch(tdb, key);
        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--;
                        if ((dbuf.dsize - (sizeof(*data) + (i+1)*sizeof(*shares))) > 0) {
                                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, key) == -1)
                                count = -1;
                } else {
                        if (tdb_store(tdb, key, 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;
        TDB_DATA key = locking_key_fsp(fsp);
        BOOL ret = True;
                
        /* read in the existing share modes if any */
        dbuf = tdb_fetch(tdb, key);
        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, key, 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, key, 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;
        TDB_DATA key = locking_key(dev, inode);

        /* read in the existing share modes */
        dbuf = tdb_fetch(tdb, key);
        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, key) == -1)
                                ret = False;
                } else {
                        if (tdb_store(tdb, key, 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;
        TDB_DATA key = locking_key(dev, inode);

        /* read in the existing share modes */
        dbuf = tdb_fetch(tdb, key);
        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, key, dbuf, TDB_REPLACE)==-1) {
                        SAFE_FREE(dbuf.dptr);
                        return False;
                }
        }

        SAFE_FREE(dbuf.dptr);
        return True;
}

/*******************************************************************
 Print out a deferred open entry.
********************************************************************/

char *deferred_open_str(int num, deferred_open_entry *e)
{
        static pstring de_str;

        slprintf(de_str, sizeof(de_str)-1, "deferred_open_entry[%d]: \
pid = %lu, mid = %u, dev = 0x%x, inode = %.0f, port = %u, time = [%u.%06u]",
                num, (unsigned long)e->pid, (unsigned int)e->mid, (unsigned int)e->dev, (double)e->inode,
                (unsigned int)e->port,
                (unsigned int)e->time.tv_sec, (unsigned int)e->time.tv_usec );

        return de_str;
}

/* Internal data structures for deferred opens... */

struct de_locking_key {
        char name[4];
        SMB_DEV_T dev;
        SMB_INO_T inode;
};

struct deferred_open_data {
        union {
                int num_deferred_open_entries;
                deferred_open_entry dummy; /* Needed for alignment. */
        } u;
        /* the following two entries are implicit
           deferred_open_entry de_entries[num_deferred_open_entries];
           char file_name[];
        */
};

/*******************************************************************
 Print out a deferred open table.
********************************************************************/

static void print_deferred_open_table(struct deferred_open_data *data)
{
        int num_de_entries = data->u.num_deferred_open_entries;
        deferred_open_entry *de_entries = (deferred_open_entry *)(data + 1);
        int i;

        for (i = 0; i < num_de_entries; i++) {
                deferred_open_entry *entry_p = &de_entries[i];
                DEBUG(10,("print_deferred_open_table: %s\n", deferred_open_str(i, entry_p) ));
        }
}


/*******************************************************************
 Form a static deferred open locking key for a dev/inode pair.
******************************************************************/

static TDB_DATA deferred_open_locking_key(SMB_DEV_T dev, SMB_INO_T inode)
{
        static struct de_locking_key key;
        TDB_DATA kbuf;

        memset(&key, '\0', sizeof(key));
        memcpy(&key.name[0], "DOE", 4);
        key.dev = dev;
        key.inode = inode;
        kbuf.dptr = (char *)&key;
        kbuf.dsize = sizeof(key);
        return kbuf;
}

/*******************************************************************
 Get all deferred open entries for a dev/inode pair.
********************************************************************/

int get_deferred_opens(connection_struct *conn, 
                    SMB_DEV_T dev, SMB_INO_T inode, 
                    deferred_open_entry **pp_de_entries)
{
        TDB_DATA dbuf;
        struct deferred_open_data *data;
        int num_de_entries;
        deferred_open_entry *de_entries = NULL;
        TDB_DATA key = deferred_open_locking_key(dev, inode);

        *pp_de_entries = NULL;

        dbuf = tdb_fetch(tdb, key);
        if (!dbuf.dptr)
                return 0;

        data = (struct deferred_open_data *)dbuf.dptr;
        num_de_entries = data->u.num_deferred_open_entries;
        if(num_de_entries) {
                pstring fname;
                int i;
                int del_count = 0;

                de_entries = (deferred_open_entry *)memdup(dbuf.dptr + sizeof(*data),   
                                                num_de_entries * sizeof(deferred_open_entry));

                if (!de_entries) {
                        SAFE_FREE(dbuf.dptr);
                        return 0;
                }

                /* Save off the associated filename. */
                pstrcpy(fname, dbuf.dptr + sizeof(*data) + num_de_entries * sizeof(deferred_open_entry));

                /*
                 * Ensure that each entry has a real process attached.
                 */

                for (i = 0; i < num_de_entries; ) {
                        deferred_open_entry *entry_p = &de_entries[i];
                        if (process_exists(entry_p->pid)) {
                                DEBUG(10,("get_deferred_opens: %s\n", deferred_open_str(i, entry_p) ));
                                i++;
                        } else {
                                DEBUG(10,("get_deferred_opens: deleted %s\n", deferred_open_str(i, entry_p) ));
                                if (num_de_entries - i - 1 > 0) {
                                        memcpy( &de_entries[i], &de_entries[i+1],
                                                sizeof(deferred_open_entry) * (num_de_entries - i - 1));
                                }
                                num_de_entries--;
                                del_count++;
                        }
                }

                /* Did we delete any ? If so, re-store in tdb. */
                if (del_count) {
                        data->u.num_deferred_open_entries = num_de_entries;
                        
                        if (num_de_entries) {
                                memcpy(dbuf.dptr + sizeof(*data), de_entries,
                                                num_de_entries * sizeof(deferred_open_entry));
                                /* Append the filename. */
                                pstrcpy(dbuf.dptr + sizeof(*data) + num_de_entries * sizeof(deferred_open_entry), fname);
                        }

                        /* The record has shrunk a bit */
                        dbuf.dsize -= del_count * sizeof(deferred_open_entry);

                        if (data->u.num_deferred_open_entries == 0) {
                                if (tdb_delete(tdb, key) == -1) {
                                        SAFE_FREE(de_entries);
                                        SAFE_FREE(dbuf.dptr);
                                        return 0;
                                }
                        } else {
                                if (tdb_store(tdb, key, dbuf, TDB_REPLACE) == -1) {
                                        SAFE_FREE(de_entries);
                                        SAFE_FREE(dbuf.dptr);
                                        return 0;
                                }
                        }
                }
        }

        SAFE_FREE(dbuf.dptr);
        *pp_de_entries = de_entries;
        return num_de_entries;
}

/*******************************************************************
 Check if two deferred open entries are identical.
********************************************************************/

static BOOL deferred_open_entries_identical( deferred_open_entry *e1, deferred_open_entry *e2)
{
        return (e1->pid == e2->pid &&
                e1->mid == e2->mid &&
                e1->port == e2->port &&
                e1->dev == e2->dev &&
                e1->inode == e2->inode &&
                e1->time.tv_sec == e2->time.tv_sec &&
                e1->time.tv_usec == e2->time.tv_usec);
}

/*******************************************************************
 Delete a specific deferred open entry.
 Ignore if no entry deleted.
********************************************************************/

BOOL delete_deferred_open_entry(deferred_open_entry *entry)
{
        TDB_DATA dbuf;
        struct deferred_open_data *data;
        int i, del_count=0;
        deferred_open_entry *de_entries;
        BOOL ret = True;
        TDB_DATA key = deferred_open_locking_key(entry->dev, entry->inode);

        /* read in the existing share modes */
        dbuf = tdb_fetch(tdb, key);
        if (!dbuf.dptr)
                return -1;

        data = (struct deferred_open_data *)dbuf.dptr;
        de_entries = (deferred_open_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,("delete_deferred_open_entry: num_deferred_open_entries = %d\n",
                data->u.num_deferred_open_entries ));

        for (i=0;i<data->u.num_deferred_open_entries;) {
                if (deferred_open_entries_identical(&de_entries[i], entry)) {
                        DEBUG(10,("delete_deferred_open_entry: deleted %s\n",
                                deferred_open_str(i, &de_entries[i]) ));

                        data->u.num_deferred_open_entries--;
                        if ((dbuf.dsize - (sizeof(*data) + (i+1)*sizeof(*de_entries))) > 0) {
                                memmove(&de_entries[i], &de_entries[i+1], 
                                        dbuf.dsize - (sizeof(*data) + (i+1)*sizeof(*de_entries)));
                        }
                        del_count++;

                        DEBUG(10,("delete_deferred_open_entry: deleting entry %d\n", i ));

                } else {
                        i++;
                }
        }

        SMB_ASSERT(del_count == 0 || del_count == 1);

        if (del_count) {
                /* the record may have shrunk a bit */
                dbuf.dsize -= del_count * sizeof(*de_entries);

                /* store it back in the database */
                if (data->u.num_deferred_open_entries == 0) {
                        if (tdb_delete(tdb, key) == -1)
                                ret = False;
                } else {
                        if (tdb_store(tdb, key, dbuf, TDB_REPLACE) == -1)
                                ret = False;
                }
        }
        DEBUG(10,("delete_deferred_open_entry: Remaining table.\n"));
        print_deferred_open_table((struct deferred_open_data*)dbuf.dptr);
        SAFE_FREE(dbuf.dptr);
        return ret;
}

/*******************************************************************
 Fill a deferred open entry.
********************************************************************/

static void fill_deferred_open(char *p, uint16 mid, struct timeval *ptv, SMB_DEV_T dev, SMB_INO_T inode, uint16 port)
{
        deferred_open_entry *e = (deferred_open_entry *)p;
        void *x = &e->time; /* Needed to force alignment. p may not be aligned.... */

        memset(e, '\0', sizeof(deferred_open_entry));
        e->mid = mid;
        e->pid = sys_getpid();
        memcpy(x, ptv, sizeof(struct timeval));
        e->dev = dev;
        e->inode = inode;
        e->port = port;
}

/*******************************************************************
 Add a deferred open record. Return False on fail, True on success.
********************************************************************/

BOOL add_deferred_open(uint16 mid, struct timeval *ptv, SMB_DEV_T dev, SMB_INO_T inode, uint16 port, const char *fname)
{
        TDB_DATA dbuf;
        struct deferred_open_data *data;
        char *p=NULL;
        int size;
        TDB_DATA key = deferred_open_locking_key(dev, inode);
        BOOL ret = True;
                
        /* read in the existing deferred open records if any */
        dbuf = tdb_fetch(tdb, key);
        if (!dbuf.dptr) {
                size_t offset;
                /* we'll need to create a new record */

                size = sizeof(*data) + sizeof(deferred_open_entry) + strlen(fname) + 1;
                p = (char *)malloc(size);
                if (!p)
                        return False;
                data = (struct deferred_open_data *)p;
                data->u.num_deferred_open_entries = 1;
        
                DEBUG(10,("add_deferred_open: creating entry for file %s. num_deferred_open_entries = 1\n",
                        fname ));

                offset = sizeof(*data) + sizeof(deferred_open_entry);
                safe_strcpy(p + offset, fname, size - offset - 1);
                fill_deferred_open(p + sizeof(*data), mid, ptv, dev, inode, port);
                dbuf.dptr = p;
                dbuf.dsize = size;
                if (tdb_store(tdb, key, dbuf, TDB_REPLACE) == -1)
                        ret = False;

                print_deferred_open_table((struct deferred_open_data *)p);

                SAFE_FREE(p);
                return ret;
        }

        /* we're adding to an existing entry - this is a bit fiddly */
        data = (struct deferred_open_data *)dbuf.dptr;

        data->u.num_deferred_open_entries++;
        
        DEBUG(10,("add_deferred_open: adding entry for file %s. new num_deferred_open_entries = %d\n",
                fname, data->u.num_deferred_open_entries ));

        size = dbuf.dsize + sizeof(deferred_open_entry);
        p = malloc(size);
        if (!p) {
                SAFE_FREE(dbuf.dptr);
                return False;
        }
        memcpy(p, dbuf.dptr, sizeof(*data));
        fill_deferred_open(p + sizeof(*data), mid, ptv, dev, inode, port);
        memcpy(p + sizeof(*data) + sizeof(deferred_open_entry), dbuf.dptr + sizeof(*data),
               dbuf.dsize - sizeof(*data));
        SAFE_FREE(dbuf.dptr);
        dbuf.dptr = p;
        dbuf.dsize = size;
        if (tdb_store(tdb, key, dbuf, TDB_REPLACE) == -1)
                ret = False;
        print_deferred_open_table((struct deferred_open_data *)p);
        SAFE_FREE(p);
        return ret;
}

/****************************************************************************
 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;

        /* Ensure this is a locking_key record. */
        if (kbuf.dsize != sizeof(struct locking_key))
                return 0;

        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);
}