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the bulk of the new byte range locking coode

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it doesn't map to posix locks yet, that will come later.
(This used to be commit 7f2a493095887cb0aae915ac36b9cded71d3a7a7)
This commit is contained in:
Andrew Tridgell 2000-01-13 12:09:36 +00:00
parent 6bad53f758
commit 6c2a1fdf36
2 changed files with 296 additions and 45 deletions
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275
source3/locking/brlock.c Normal file
View File

@ -0,0 +1,275 @@
/*
Unix SMB/Netbios implementation.
Version 3.0
byte range locking code
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.
*/
/* this module implements a tdb based byte range locking service,
replacing the fcntl() based byte range locking previously
used. This allows us to provide the same semantics as NT */
#include "includes.h"
extern int DEBUGLEVEL;
/* this contains elements that differentiate locks. The smbpid is a
client supplied pid, and is essentially the locking context for
this client */
struct lock_context {
uint16 smbpid;
uint16 tid;
pid_t pid;
};
/* the data in brlock records is an unsorted linear array of these
records. It is unnecessary to store the count as tdb provides the
size of the record */
struct lock_struct {
struct lock_context context;
br_off start;
br_off size;
enum lock_type lock_type;
};
/* the key used in the brlock database */
struct lock_key {
SMB_DEV_T device;
SMB_INO_T inode;
};
/* the open brlock.tdb database */
static TDB_CONTEXT *tdb;
/****************************************************************************
see if two locking contexts are equal
****************************************************************************/
static BOOL brl_same_context(struct lock_context *ctx1,
struct lock_context *ctx2)
{
return (ctx1->pid == ctx2->pid) &&
(ctx1->smbpid == ctx2->smbpid) &&
(ctx1->tid == ctx2->tid);
}
/****************************************************************************
see if lock2 can be added when lock1 is in place
****************************************************************************/
static BOOL brl_conflict(struct lock_struct *lck1,
struct lock_struct *lck2)
{
if (lck1->lock_type == READ_LOCK && lck2->lock_type == READ_LOCK) return False;
if (brl_same_context(&lck1->context, &lck2->context) &&
lck2->lock_type == READ_LOCK) return False;
if (lck1->start >= (lck2->start + lck2->size) ||
lck2->start >= (lck1->start + lck1->size)) return False;
return True;
}
/****************************************************************************
open up the brlock.tdb database
****************************************************************************/
void brl_init(void)
{
if (tdb) return;
tdb = tdb_open(lock_path("brlock.tdb"), 0, TDB_CLEAR_IF_FIRST,
O_RDWR | O_CREAT, 0644);
if (!tdb) {
DEBUG(0,("Failed to open byte range locking database\n"));
}
}
/****************************************************************************
lock a range of bytes
****************************************************************************/
BOOL brl_lock(SMB_DEV_T dev, SMB_INO_T ino,
uint16 smbpid, pid_t pid, uint16 tid,
br_off start, br_off size,
enum lock_type lock_type)
{
struct lock_key key;
TDB_DATA kbuf, dbuf;
int count, i;
struct lock_struct lock, *locks;
key.device = dev;
key.inode = ino;
kbuf.dptr = (char *)&key;
kbuf.dsize = sizeof(key);
dbuf.dptr = NULL;
tdb_lockchain(tdb, kbuf);
dbuf = tdb_fetch(tdb, kbuf);
lock.context.smbpid = smbpid;
lock.context.pid = pid;
lock.context.tid = tid;
lock.start = start;
lock.size = size;
lock.lock_type = lock_type;
if (dbuf.dptr) {
/* there are existing locks - make sure they don't conflict */
locks = (struct lock_struct *)dbuf.dptr;
count = dbuf.dsize / sizeof(*locks);
for (i=0; i<count; i++) {
if (brl_conflict(&locks[i], &lock)) {
goto fail;
}
}
}
/* no conflicts - add it to the list of locks */
dbuf.dptr = Realloc(dbuf.dptr, dbuf.dsize + sizeof(*locks));
if (!dbuf.dptr) goto fail;
memcpy(dbuf.dptr + dbuf.dsize, &lock, sizeof(lock));
dbuf.dsize += sizeof(lock);
tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
free(dbuf.dptr);
tdb_unlockchain(tdb, kbuf);
return True;
fail:
if (dbuf.dptr) free(dbuf.dptr);
tdb_unlockchain(tdb, kbuf);
return False;
}
/****************************************************************************
unlock a range of bytes
****************************************************************************/
BOOL brl_unlock(SMB_DEV_T dev, SMB_INO_T ino,
uint16 smbpid, pid_t pid, uint16 tid,
br_off start, br_off size)
{
struct lock_key key;
TDB_DATA kbuf, dbuf;
int count, i;
struct lock_struct *locks;
struct lock_context context;
key.device = dev;
key.inode = ino;
kbuf.dptr = (char *)&key;
kbuf.dsize = sizeof(key);
dbuf.dptr = NULL;
tdb_lockchain(tdb, kbuf);
dbuf = tdb_fetch(tdb, kbuf);
if (!dbuf.dptr) goto fail;
context.smbpid = smbpid;
context.pid = pid;
context.tid = tid;
/* there are existing locks - find a match */
locks = (struct lock_struct *)dbuf.dptr;
count = dbuf.dsize / sizeof(*locks);
for (i=0; i<count; i++) {
if (brl_same_context(&locks[i].context, &context) &&
locks[i].start == start &&
locks[i].size == size) {
/* found it - delete it */
if (count == 1) {
tdb_delete(tdb, kbuf);
} else {
if (i < count-1) {
memmove(&locks[i], &locks[i+1],
sizeof(*locks)*((count-1) - i));
}
dbuf.dsize -= sizeof(*locks);
tdb_store(tdb, kbuf, dbuf, TDB_REPLACE);
}
free(dbuf.dptr);
tdb_unlockchain(tdb, kbuf);
return True;
}
}
/* we didn't find it */
fail:
if (dbuf.dptr) free(dbuf.dptr);
tdb_unlockchain(tdb, kbuf);
return False;
}
/****************************************************************************
test if we could add a lock if we wanted to
****************************************************************************/
BOOL brl_locktest(SMB_DEV_T dev, SMB_INO_T ino,
uint16 smbpid, pid_t pid, uint16 tid,
br_off start, br_off size,
enum lock_type lock_type)
{
struct lock_key key;
TDB_DATA kbuf, dbuf;
int count, i;
struct lock_struct lock, *locks;
key.device = dev;
key.inode = ino;
kbuf.dptr = (char *)&key;
kbuf.dsize = sizeof(key);
dbuf.dptr = NULL;
tdb_lockchain(tdb, kbuf);
dbuf = tdb_fetch(tdb, kbuf);
lock.context.smbpid = smbpid;
lock.context.pid = pid;
lock.context.tid = tid;
lock.start = start;
lock.size = size;
lock.lock_type = lock_type;
if (dbuf.dptr) {
/* there are existing locks - make sure they don't conflict */
locks = (struct lock_struct *)dbuf.dptr;
count = dbuf.dsize / sizeof(*locks);
for (i=0; i<count; i++) {
if (brl_conflict(&locks[i], &lock)) {
goto fail;
}
}
}
/* no conflicts - we could have added it */
free(dbuf.dptr);
tdb_unlockchain(tdb, kbuf);
return True;
fail:
if (dbuf.dptr) free(dbuf.dptr);
tdb_unlockchain(tdb, kbuf);
return False;
}

66
source3/locking/locking.c
View File

@ -38,41 +38,12 @@ extern int DEBUGLEVEL;
/* the locking database handle */
static TDB_CONTEXT *tdb;
/****************************************************************************
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(files_struct *fsp,connection_struct *conn,
SMB_OFF_T count,SMB_OFF_T offset, int lock_type)
SMB_OFF_T count,SMB_OFF_T offset,
enum lock_type lock_type)
{
int snum = SNUM(conn);
@ -82,13 +53,9 @@ BOOL is_locked(files_struct *fsp,connection_struct *conn,
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,SMB_F_GETLK,offset,count,lock_type));
return !brl_locktest(fsp->fd_ptr->inode, fsp->fd_ptr->dev,
1, getpid(), conn->cnum,
offset, count, lock_type);
}
@ -96,7 +63,7 @@ BOOL is_locked(files_struct *fsp,connection_struct *conn,
Utility function called by locking requests.
****************************************************************************/
BOOL do_lock(files_struct *fsp,connection_struct *conn,
SMB_OFF_T count,SMB_OFF_T offset,int lock_type,
SMB_OFF_T count,SMB_OFF_T offset,enum lock_type lock_type,
int *eclass,uint32 *ecode)
{
BOOL ok = False;
@ -113,9 +80,12 @@ BOOL do_lock(files_struct *fsp,connection_struct *conn,
DEBUG(10,("do_lock: lock type %d start=%.0f len=%.0f requested for file %s\n",
lock_type, (double)offset, (double)count, fsp->fsp_name ));
if (OPEN_FSP(fsp) && fsp->can_lock && (fsp->conn == conn))
ok = fcntl_lock(fsp->fd_ptr->fd,SMB_F_SETLK,offset,count,
map_lock_type(fsp,lock_type));
if (OPEN_FSP(fsp) && fsp->can_lock && (fsp->conn == conn)) {
ok = brl_lock(fsp->fd_ptr->inode, fsp->fd_ptr->dev,
1, getpid(), conn->cnum,
offset, count,
lock_type);
}
if (!ok) {
*eclass = ERRDOS;
@ -130,7 +100,8 @@ BOOL do_lock(files_struct *fsp,connection_struct *conn,
Utility function called by unlocking requests.
****************************************************************************/
BOOL do_unlock(files_struct *fsp,connection_struct *conn,
SMB_OFF_T count,SMB_OFF_T offset,int *eclass,uint32 *ecode)
SMB_OFF_T count,SMB_OFF_T offset,
int *eclass,uint32 *ecode)
{
BOOL ok = False;
@ -140,8 +111,11 @@ BOOL do_unlock(files_struct *fsp,connection_struct *conn,
DEBUG(10,("do_unlock: unlock start=%.0f len=%.0f requested for file %s\n",
(double)offset, (double)count, fsp->fsp_name ));
if (OPEN_FSP(fsp) && fsp->can_lock && (fsp->conn == conn))
ok = fcntl_lock(fsp->fd_ptr->fd,SMB_F_SETLK,offset,count,F_UNLCK);
if (OPEN_FSP(fsp) && fsp->can_lock && (fsp->conn == conn)) {
ok = brl_unlock(fsp->fd_ptr->inode, fsp->fd_ptr->dev,
1, getpid(), conn->cnum,
offset, count);
}
if (!ok) {
*eclass = ERRDOS;
@ -156,6 +130,8 @@ BOOL do_unlock(files_struct *fsp,connection_struct *conn,
****************************************************************************/
BOOL locking_init(int read_only)
{
brl_init();
if (tdb) return True;
tdb = tdb_open(lock_path("locking.tdb"),