summaryrefslogtreecommitdiff
path: root/source4/ntvfs/common
diff options
context:
space:
mode:
Diffstat (limited to 'source4/ntvfs/common')
-rw-r--r--source4/ntvfs/common/opendb.c145
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;
+}