r3127: added the initial code for the open files database. Doesn't do

anything yet, but will soon be the core of the shares modes code.
(This used to be commit ad1edabf95c6c331aac4f0caa7d31193e26bc176)

1 files changed, 145 insertions, 0 deletions

diff --git a/source4/ntvfs/common/opendb.c b/source4/ntvfs/common/opendb.c
new file mode 100644
index 0000000000..cf0177e333
--- /dev/null
+++ b/source4/ntvfs/common/opendb.c
@@ -0,0 +1,145 @@
+/* 
+   Unix SMB/CIFS implementation.
+
+   Copyright (C) Andrew Tridgell 2004
+   
+   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 is the open files database. It implements shared storage of
+  what files are open between server instances, and implements the rules
+  of shared access to files.
+
+  The caller needs to provide a file_key, which specifies what file
+  they are talking about. This needs to be a unique key across all
+  filesystems, and is usually implemented in terms of a device/inode
+  pair.
+
+  Before any operations can be performed the caller needs to establish
+  a lock on the record associated with file_key. That is done by
+  calling odb_lock(). The caller releases this lock by calling
+  talloc_free() on the returned handle.
+
+  All other operations on a record are done by passing the odb_lock()
+  handle back to this module. The handle contains internal
+  intformation about what file_key is being operated on.
+*/
+
+#include "includes.h"
+
+struct odb_context {
+	struct tdb_wrap *w;
+	servid_t server;
+	uint16_t tid;
+	void *messaging_ctx;
+};
+
+/* 
+   the database is indexed by a file_key, and contains entries of the
+   following form
+*/
+struct odb_entry {
+	servid_t server;
+	uint16_t tid;
+	uint16_t fnum;
+	uint32_t share_access;
+	uint32_t desired_access;
+	uint32_t create_options;
+};
+
+
+/*
+  an odb lock handle. You must obtain one of these using odb_lock() before doing
+  any other operations. 
+*/
+struct odb_lock {
+	struct odb_context *odb;
+	TDB_DATA key;
+};
+
+/*
+  Open up the openfiles.tdb database. Close it down using
+  talloc_free(). We need the messaging_ctx to allow for pending open
+  notifications.
+*/
+struct odb_context *odb_init(TALLOC_CTX *mem_ctx, servid_t server, uint16_t tid, 
+			     void *messaging_ctx)
+{
+	char *path;
+	struct odb_context *odb;
+
+	odb = talloc_p(mem_ctx, struct odb_context);
+	if (odb == NULL) {
+		return NULL;
+	}
+
+	path = lock_path(odb, "openfiles.tdb");
+	odb->w = tdb_wrap_open(odb, path, 0,  
+			       TDB_DEFAULT|TDB_CLEAR_IF_FIRST,
+			       O_RDWR|O_CREAT, 0600);
+	talloc_free(path);
+	if (odb->w == NULL) {
+		talloc_free(odb);
+		return NULL;
+	}
+
+	odb->server = server;
+	odb->tid = tid;
+	odb->messaging_ctx = messaging_ctx;
+
+	return odb;
+}
+
+/*
+  destroy a lock on the database
+*/
+static int odb_lock_destructor(void *ptr)
+{
+	struct odb_lock *lck = ptr;
+	tdb_chainunlock(lck->odb->w->tdb, lck->key);
+	return 0;
+}
+
+/*
+  get a lock on a entry in the odb. This call returns a lock handle,
+  which the caller should unlock using talloc_free().
+*/
+struct odb_lock *odb_lock(struct odb_context *odb, DATA_BLOB *file_key)
+{
+	struct odb_lock *lck;
+
+	lck = talloc_p(odb, struct odb_lock);
+	if (lck == NULL) {
+		return NULL;
+	}
+
+	lck->odb = odb;
+	lck->key.dptr = talloc_memdup(lck, file_key->data, file_key->length);
+	lck->key.dsize = file_key->length;
+	if (lck->key.dptr == NULL) {
+		talloc_free(lck);
+		return NULL;
+	}
+
+	if (tdb_chainlock(odb->w->tdb, lck->key) != 0) {
+		talloc_free(lck);
+		return NULL;
+	}
+
+	talloc_set_destructor(lck, odb_lock_destructor);
+	
+	return lck;
+}