r3012: added initial support for byte range locking in the posix vfs. This is

enough for us to pass locktest, but does not yet support lock timeouts
and some of the other esoteric features.
(This used to be commit 58a92abd88f190bc60894a68e0528e95ae33fe39)

1 files changed, 418 insertions, 0 deletions

diff --git a/source4/ntvfs/common/brlock.c b/source4/ntvfs/common/brlock.c
new file mode 100644
index 0000000000..0eb644e943
--- /dev/null
+++ b/source4/ntvfs/common/brlock.c
@@ -0,0 +1,418 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   generic byte range locking code
+
+   Copyright (C) Andrew Tridgell 1992-2004
+   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.
+*/
+
+/* 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"
+
+struct brl_context {
+	struct tdb_wrap *w;
+	servid_t server;
+	uint16_t tid;
+};
+
+/*
+  in this module a "DATA_BLOB *file_key" is a blob that uniquely identifies
+  a file. For a local posix filesystem this will usually be a combination
+  of the device and inode numbers of the file, but it can be anything 
+  that uniquely idetifies a file for locking purposes, as long
+  as it is applied consistently.
+*/
+
+/*
+  the lock context contains the elements that define whether one
+  lock is the same as another lock
+*/
+struct lock_context {
+	servid_t server;
+	uint16_t smbpid;
+	uint16_t tid;
+};
+
+/* 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;
+	uint64_t start;
+	uint64_t size;
+	uint16_t fnum;
+	enum brl_type lock_type;
+};
+
+/*
+  Open up the brlock.tdb database. Close it down using
+  talloc_free()
+*/
+void *brl_init(TALLOC_CTX *mem_ctx, servid_t server, uint16_t tid)
+{
+	char *path;
+	struct brl_context *brl;
+
+	brl = talloc_p(mem_ctx, struct brl_context);
+	if (brl == NULL) {
+		return NULL;
+	}
+
+	path = lock_path(brl, "brlock.tdb");
+	brl->w = tdb_wrap_open(brl, path, 0,  
+			       TDB_DEFAULT|TDB_CLEAR_IF_FIRST,
+			       O_RDWR|O_CREAT, 0600);
+	talloc_free(path);
+	if (brl->w == NULL) {
+		talloc_free(brl);
+		return NULL;
+	}
+
+	brl->server = server;
+	brl->tid = tid;
+
+	return (void *)brl;
+}
+
+
+/*
+  see if two locking contexts are equal
+*/
+static BOOL brl_same_context(struct lock_context *ctx1, struct lock_context *ctx2)
+{
+	return (ctx1->server == ctx2->server &&
+		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 && lck1->fnum == lck2->fnum) {
+		return False;
+	}
+
+	if (lck1->start >= (lck2->start + lck2->size) ||
+	    lck2->start >= (lck1->start + lck1->size)) {
+		return False;
+	}
+	    
+	return True;
+} 
+
+
+/*
+ Check to see if this lock conflicts, but ignore our own locks on the
+ same fnum only.
+*/
+static BOOL brl_conflict_other(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) &&
+	    lck1->fnum == lck2->fnum) {
+		return False;
+	}
+
+	if (lck1->start >= (lck2->start + lck2->size) ||
+	    lck2->start >= (lck1->start + lck1->size))
+		return False;
+	    
+	return True;
+} 
+
+
+
+/*
+ Lock a range of bytes.
+*/
+NTSTATUS brl_lock(void *brl_ctx,
+		  DATA_BLOB *file_key, 
+		  uint16_t smbpid,
+		  uint16_t fnum, 
+		  uint64_t start, uint64_t size, 
+		  enum brl_type lock_type)
+{
+	struct brl_context *brl = brl_ctx;
+	TDB_DATA kbuf, dbuf;
+	int count, i;
+	struct lock_struct lock, *locks;
+	char *tp;
+	NTSTATUS status;
+
+	kbuf.dptr = file_key->data;
+	kbuf.dsize = file_key->length;
+
+	if (tdb_chainlock(brl->w->tdb, kbuf) != 0) {
+		return NT_STATUS_INTERNAL_DB_CORRUPTION;
+	}
+
+	dbuf = tdb_fetch(brl->w->tdb, kbuf);
+
+	lock.context.smbpid = smbpid;
+	lock.context.server = brl->server;
+	lock.context.tid = brl->tid;
+	lock.start = start;
+	lock.size = size;
+	lock.fnum = fnum;
+	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)) {
+				status = NT_STATUS_LOCK_NOT_GRANTED;
+				goto fail;
+			}
+		}
+	}
+
+	/* no conflicts - add it to the list of locks */
+	tp = Realloc(dbuf.dptr, dbuf.dsize + sizeof(*locks));
+	if (!tp) {
+		status = NT_STATUS_NO_MEMORY;
+		goto fail;
+	} else {
+		dbuf.dptr = tp;
+	}
+	memcpy(dbuf.dptr + dbuf.dsize, &lock, sizeof(lock));
+	dbuf.dsize += sizeof(lock);
+
+	if (tdb_store(brl->w->tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
+		status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+		goto fail;
+	}
+
+	free(dbuf.dptr);
+	tdb_chainunlock(brl->w->tdb, kbuf);
+	return NT_STATUS_OK;
+
+ fail:
+
+	free(dbuf.dptr);
+	tdb_chainunlock(brl->w->tdb, kbuf);
+	return status;
+}
+
+
+/*
+ Unlock a range of bytes.
+*/
+NTSTATUS brl_unlock(void *brl_ctx,
+		    DATA_BLOB *file_key, 
+		    uint16_t smbpid,
+		    uint16_t fnum,
+		    uint64_t start, uint64_t size)
+{
+	struct brl_context *brl = brl_ctx;
+	TDB_DATA kbuf, dbuf;
+	int count, i;
+	struct lock_struct *locks;
+	struct lock_context context;
+	NTSTATUS status;
+
+	kbuf.dptr = file_key->data;
+	kbuf.dsize = file_key->length;
+
+	if (tdb_chainlock(brl->w->tdb, kbuf) != 0) {
+		return NT_STATUS_INTERNAL_DB_CORRUPTION;
+	}
+
+	dbuf = tdb_fetch(brl->w->tdb, kbuf);
+	if (!dbuf.dptr) {
+		tdb_chainunlock(brl->w->tdb, kbuf);
+		return NT_STATUS_RANGE_NOT_LOCKED;
+	}
+
+	context.smbpid = smbpid;
+	context.server = brl->server;
+	context.tid = brl->tid;
+
+	/* there are existing locks - find a match */
+	locks = (struct lock_struct *)dbuf.dptr;
+	count = dbuf.dsize / sizeof(*locks);
+
+	locks = (struct lock_struct *)dbuf.dptr;
+	count = dbuf.dsize / sizeof(*locks);
+	for (i=0; i<count; i++) {
+		struct lock_struct *lock = &locks[i];
+		
+		if (brl_same_context(&lock->context, &context) &&
+		    lock->fnum == fnum &&
+		    lock->start == start &&
+		    lock->size == size) {
+			/* found it - delete it */
+			if (count == 1) {
+				if (tdb_delete(brl->w->tdb, kbuf) != 0) {
+					status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+					goto fail;
+				}
+			} else {
+				if (i < count-1) {
+					memmove(&locks[i], &locks[i+1], 
+						sizeof(*locks)*((count-1) - i));
+				}
+				dbuf.dsize -= sizeof(*locks);
+				if (tdb_store(brl->w->tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
+					status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+					goto fail;
+				}
+			}
+			
+			free(dbuf.dptr);
+			tdb_chainunlock(brl->w->tdb, kbuf);
+			return NT_STATUS_OK;
+		}
+	}
+	
+	/* we didn't find it */
+	status = NT_STATUS_RANGE_NOT_LOCKED;
+
+ fail:
+	free(dbuf.dptr);
+	tdb_chainunlock(brl->w->tdb, kbuf);
+	return status;
+}
+
+
+/*
+  Test if we are allowed to perform IO on a region of an open file
+*/
+NTSTATUS brl_locktest(void *brl_ctx,
+		      DATA_BLOB *file_key, 
+		      uint16_t fnum,
+		      uint16 smbpid, 
+		      uint64_t start, uint64_t size, 
+		      enum brl_type lock_type)
+{
+	struct brl_context *brl = brl_ctx;
+	TDB_DATA kbuf, dbuf;
+	int count, i;
+	struct lock_struct lock, *locks;
+
+	kbuf.dptr = file_key->data;
+	kbuf.dsize = file_key->length;
+
+	dbuf = tdb_fetch(brl->w->tdb, kbuf);
+	if (dbuf.dptr == NULL) {
+		return NT_STATUS_OK;
+	}
+
+	lock.context.smbpid = smbpid;
+	lock.context.server = brl->server;
+	lock.context.tid = brl->tid;
+	lock.start = start;
+	lock.size = size;
+	lock.fnum = fnum;
+	lock.lock_type = lock_type;
+
+	/* 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_other(&locks[i], &lock)) {
+			free(dbuf.dptr);
+			return NT_STATUS_FILE_LOCK_CONFLICT;
+		}
+	}
+
+	free(dbuf.dptr);
+	return NT_STATUS_OK;
+}
+
+
+/*
+ Remove any locks associated with a open file.
+*/
+NTSTATUS brl_close(void *brl_ctx,
+		   DATA_BLOB *file_key, int fnum)
+{
+	struct brl_context *brl = brl_ctx;
+	TDB_DATA kbuf, dbuf;
+	int count, i, dcount=0;
+	struct lock_struct *locks;
+	NTSTATUS status;
+
+	kbuf.dptr = file_key->data;
+	kbuf.dsize = file_key->length;
+
+	if (tdb_chainlock(brl->w->tdb, kbuf) != 0) {
+		return NT_STATUS_INTERNAL_DB_CORRUPTION;
+	}
+
+	dbuf = tdb_fetch(brl->w->tdb, kbuf);
+	if (!dbuf.dptr) {
+		tdb_chainunlock(brl->w->tdb, kbuf);
+		return NT_STATUS_OK;
+	}
+
+	/* there are existing locks - remove any for this fnum */
+	locks = (struct lock_struct *)dbuf.dptr;
+	count = dbuf.dsize / sizeof(*locks);
+
+	for (i=0; i<count; i++) {
+		struct lock_struct *lock = &locks[i];
+
+		if (lock->context.tid == brl->tid &&
+		    lock->context.server == brl->server &&
+		    lock->fnum == fnum) {
+			/* found it - delete it */
+			if (count > 1 && i < count-1) {
+				memmove(&locks[i], &locks[i+1], 
+					sizeof(*locks)*((count-1) - i));
+			}
+			count--;
+			i--;
+			dcount++;
+		}
+	}
+
+	status = NT_STATUS_OK;
+
+	if (count == 0) {
+		if (tdb_delete(brl->w->tdb, kbuf) != 0) {
+			status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+		}
+	} else if (dcount != 0) {
+		dbuf.dsize -= dcount * sizeof(*locks);
+		if (tdb_store(brl->w->tdb, kbuf, dbuf, TDB_REPLACE) != 0) {
+			status = NT_STATUS_INTERNAL_DB_CORRUPTION;
+		}
+	}
+
+	free(dbuf.dptr);
+	tdb_chainunlock(brl->w->tdb, kbuf);
+
+	return status;
+}
+