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/*
Unix SMB/Netbios implementation.
Version 1.9.
Locking functions
Copyright (C) Andrew Tridgell 1992-1998
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.
*/
#include "includes.h"
extern int DEBUGLEVEL;
extern connection_struct Connections[];
extern files_struct Files[];
static struct share_ops *share_ops;
/****************************************************************************
Utility function to map a lock type correctly depending on the real open
mode of a file.
****************************************************************************/
static int map_lock_type( files_struct *fsp, int lock_type)
{
if((lock_type == F_WRLCK) && (fsp->fd_ptr->real_open_flags == O_RDONLY)) {
/*
* Many UNIX's cannot get a write lock on a file opened read-only.
* Win32 locking semantics allow this.
* Do the best we can and attempt a read-only lock.
*/
DEBUG(10,("map_lock_type: Downgrading write lock to read due to read-only file.\n"));
return F_RDLCK;
} else if( (lock_type == F_RDLCK) && (fsp->fd_ptr->real_open_flags == O_WRONLY)) {
/*
* Ditto for read locks on write only files.
*/
DEBUG(10,("map_lock_type: Changing read lock to write due to write-only file.\n"));
return F_WRLCK;
}
/*
* This return should be the most normal, as we attempt
* to always open files read/write.
*/
return lock_type;
}
/****************************************************************************
Utility function called to see if a file region is locked.
****************************************************************************/
BOOL is_locked(int fnum,int cnum,uint32 count,uint32 offset, int lock_type)
{
int snum = SNUM(cnum);
files_struct *fsp = &Files[fnum];
if (count == 0)
return(False);
if (!lp_locking(snum) || !lp_strict_locking(snum))
return(False);
/*
* Note that most UNIX's can *test* for a write lock on
* a read-only fd, just not *set* a write lock on a read-only
* fd. So we don't need to use map_lock_type here.
*/
return(fcntl_lock(fsp->fd_ptr->fd,F_GETLK,offset,count,lock_type));
}
/****************************************************************************
Utility function called by locking requests.
****************************************************************************/
BOOL do_lock(int fnum,int cnum,uint32 count,uint32 offset,int lock_type,
int *eclass,uint32 *ecode)
{
BOOL ok = False;
files_struct *fsp = &Files[fnum];
if (!lp_locking(SNUM(cnum)))
return(True);
if (count == 0) {
*eclass = ERRDOS;
*ecode = ERRnoaccess;
return False;
}
if (OPEN_FNUM(fnum) && fsp->can_lock && (fsp->cnum == cnum))
ok = fcntl_lock(fsp->fd_ptr->fd,F_SETLK,offset,count,
map_lock_type(fsp,lock_type));
if (!ok) {
*eclass = ERRDOS;
*ecode = ERRlock;
return False;
}
return True; /* Got lock */
}
/****************************************************************************
Utility function called by unlocking requests.
****************************************************************************/
BOOL do_unlock(int fnum,int cnum,uint32 count,uint32 offset,int *eclass,uint32 *ecode)
{
BOOL ok = False;
files_struct *fsp = &Files[fnum];
if (!lp_locking(SNUM(cnum)))
return(True);
if (OPEN_FNUM(fnum) && fsp->can_lock && (fsp->cnum == cnum))
ok = fcntl_lock(fsp->fd_ptr->fd,F_SETLK,offset,count,F_UNLCK);
if (!ok) {
*eclass = ERRDOS;
*ecode = ERRlock;
return False;
}
return True; /* Did unlock */
}
/****************************************************************************
Initialise the locking functions.
****************************************************************************/
BOOL locking_init(int read_only)
{
if (share_ops) return True;
#ifdef FAST_SHARE_MODES
share_ops = locking_shm_init(read_only);
if (!share_ops) {
DEBUG(0,("ERROR: Failed to initialise fast share modes - trying slow code\n"));
}
if (share_ops) return True;
#endif
share_ops = locking_slow_init(read_only);
if (!share_ops) {
DEBUG(0,("ERROR: Failed to initialise share modes!\n"));
return False;
}
return True;
}
/*******************************************************************
Deinitialize the share_mode management.
******************************************************************/
BOOL locking_end(void)
{
if (share_ops)
return share_ops->stop_mgmt();
return True;
}
/*******************************************************************
Lock a hash bucket entry.
******************************************************************/
BOOL lock_share_entry(int cnum, uint32 dev, uint32 inode, int *ptok)
{
return share_ops->lock_entry(cnum, dev, inode, ptok);
}
/*******************************************************************
Unlock a hash bucket entry.
******************************************************************/
BOOL unlock_share_entry(int cnum, uint32 dev, uint32 inode, int token)
{
return share_ops->unlock_entry(cnum, dev, inode, token);
}
/*******************************************************************
Get all share mode entries for a dev/inode pair.
********************************************************************/
int get_share_modes(int cnum, int token, uint32 dev, uint32 inode,
share_mode_entry **shares)
{
return share_ops->get_entries(cnum, token, dev, inode, shares);
}
/*******************************************************************
Del the share mode of a file.
********************************************************************/
void del_share_mode(int token, int fnum)
{
share_ops->del_entry(token, fnum);
}
/*******************************************************************
Set the share mode of a file. Return False on fail, True on success.
********************************************************************/
BOOL set_share_mode(int token, int fnum, uint16 port, uint16 op_type)
{
return share_ops->set_entry(token, fnum, port, op_type);
}
/*******************************************************************
Remove an oplock port and mode entry from a share mode.
********************************************************************/
BOOL remove_share_oplock(int fnum, int token)
{
return share_ops->remove_oplock(fnum, token);
}
/*******************************************************************
Call the specified function on each entry under management by the
share mode system.
********************************************************************/
int share_mode_forall(void (*fn)(share_mode_entry *, char *))
{
return share_ops->forall(fn);
}
/*******************************************************************
Dump the state of the system.
********************************************************************/
void share_status(FILE *f)
{
share_ops->status(f);
}
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