source/locking/locking.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    Locking functions
   5    Copyright (C) Andrew Tridgell 1992-1997
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20
  21    Revision History:
  22
  23    12 aug 96: Erik.Devriendt@te6.siemens.be
  24    added support for shared memory implementation of share mode locking
  25
  26    May 1997. Jeremy Allison (jallison@whistle.com). Modified share mode
  27    locking to deal with multiple share modes per open file.
  28
  29    September 1997. Jeremy Allison (jallison@whistle.com). Added oplock
  30    support.
  31
  32 */
  33
  34 #include "includes.h"
  35 extern int DEBUGLEVEL;
  36 extern connection_struct Connections[];
  37 extern files_struct Files[];
  38
  39 static struct share_ops *share_ops;
  40
  41 /****************************************************************************
  42   utility function called to see if a file region is locked
  43 ****************************************************************************/
  44 BOOL is_locked(int fnum,int cnum,uint32 count,uint32 offset)
  45 {
  46   int snum = SNUM(cnum);
  47
  48   if (count == 0)
  49     return(False);
  50
  51   if (!lp_locking(snum) || !lp_strict_locking(snum))
  52     return(False);
  53
  54   return(fcntl_lock(Files[fnum].fd_ptr->fd,F_GETLK,offset,count,
  55                    (Files[fnum].can_write?F_WRLCK:F_RDLCK)));
  56 }
  57
  58
  59 /****************************************************************************
  60   utility function called by locking requests
  61 ****************************************************************************/
  62 BOOL do_lock(int fnum,int cnum,uint32 count,uint32 offset,int *eclass,uint32 *ecode)
  63 {
  64   BOOL ok = False;
  65
  66   if (!lp_locking(SNUM(cnum)))
  67     return(True);
  68
  69   if (count == 0) {
  70     *eclass = ERRDOS;
  71     *ecode = ERRnoaccess;
  72     return False;
  73   }
  74
  75   if (Files[fnum].can_lock && OPEN_FNUM(fnum) && (Files[fnum].cnum == cnum))
  76     ok = fcntl_lock(Files[fnum].fd_ptr->fd,F_SETLK,offset,count,
  77                     (Files[fnum].can_write?F_WRLCK:F_RDLCK));
  78
  79   if (!ok) {
  80     *eclass = ERRDOS;
  81     *ecode = ERRlock;
  82     return False;
  83   }
  84   return True; /* Got lock */
  85 }
  86
  87
  88 /****************************************************************************
  89   utility function called by unlocking requests
  90 ****************************************************************************/
  91 BOOL do_unlock(int fnum,int cnum,uint32 count,uint32 offset,int *eclass,uint32 *ecode)
  92 {
  93   BOOL ok = False;
  94
  95   if (!lp_locking(SNUM(cnum)))
  96     return(True);
  97
  98   if (Files[fnum].can_lock && OPEN_FNUM(fnum) && (Files[fnum].cnum == cnum))
  99     ok = fcntl_lock(Files[fnum].fd_ptr->fd,F_SETLK,offset,count,F_UNLCK);
 100
 101   if (!ok) {
 102     *eclass = ERRDOS;
 103     *ecode = ERRlock;
 104     return False;
 105   }
 106   return True; /* Did unlock */
 107 }
 108
 109
 110
 111 /****************************************************************************
 112   initialise the locking functions
 113 ****************************************************************************/
 114 BOOL locking_init(int read_only)
 115 {
 116         if (share_ops) return True;
 117
 118 #ifdef FAST_SHARE_MODES
 119         share_ops = locking_shm_init(read_only);
 120         if (!share_ops) {
 121                 DEBUG(0,("ERROR: Failed to initialise fast share modes - trying slow code\n"));
 122         }
 123         if (share_ops) return True;
 124 #endif
 125
 126         share_ops = locking_slow_init(read_only);
 127         if (!share_ops) {
 128                 DEBUG(0,("ERROR: Failed to initialise share modes!\n"));
 129                 return False;
 130         }
 131
 132         return True;
 133 }
 134
 135 /*******************************************************************
 136   deinitialize the share_mode management
 137   ******************************************************************/
 138 BOOL locking_end(void)
 139 {
 140         if (share_ops)
 141                 return share_ops->stop_mgmt();
 142         return True;
 143 }
 144
 145
 146 /*******************************************************************
 147   lock a hash bucket entry
 148   ******************************************************************/
 149 BOOL lock_share_entry(int cnum, uint32 dev, uint32 inode, int *ptok)
 150 {
 151         return share_ops->lock_entry(cnum, dev, inode, ptok);
 152 }
 153
 154 /*******************************************************************
 155   unlock a hash bucket entry
 156   ******************************************************************/
 157 BOOL unlock_share_entry(int cnum, uint32 dev, uint32 inode, int token)
 158 {
 159         return share_ops->unlock_entry(cnum, dev, inode, token);
 160 }
 161
 162 /*******************************************************************
 163 get all share mode entries for a dev/inode pair.
 164 ********************************************************************/
 165 int get_share_modes(int cnum, int token, uint32 dev, uint32 inode,
 166                     share_mode_entry **shares)
 167 {
 168         return share_ops->get_entries(cnum, token, dev, inode, shares);
 169 }
 170
 171 /*******************************************************************
 172 del the share mode of a file.
 173 ********************************************************************/
 174 void del_share_mode(int token, int fnum)
 175 {
 176         share_ops->del_entry(token, fnum);
 177 }
 178
 179 /*******************************************************************
 180 set the share mode of a file. Return False on fail, True on success.
 181 ********************************************************************/
 182 BOOL set_share_mode(int token, int fnum, uint16 port, uint16 op_type)
 183 {
 184         return share_ops->set_entry(token, fnum, port, op_type);
 185 }
 186
 187 /*******************************************************************
 188 Remove an oplock port and mode entry from a share mode.
 189 ********************************************************************/
 190 BOOL remove_share_oplock(int fnum, int token)
 191 {
 192         return share_ops->remove_oplock(fnum, token);
 193 }
 194
 195
 196 /*******************************************************************
 197 call the specified function on each entry under management by the
 198 share mode system
 199 ********************************************************************/
 200 int share_mode_forall(void (*fn)(share_mode_entry *, char *))
 201 {
 202         return share_ops->forall(fn);
 203 }
 204
 205 /*******************************************************************
 206 dump the state of the system
 207 ********************************************************************/
 208 void share_status(FILE *f)
 209 {
 210         share_ops->status(f);
 211 }