From 1cd1b172d52a1fb336cd001ac0ca2fbf7e26a9a3 Mon Sep 17 00:00:00 2001 From: Andrew Tridgell Date: Fri, 22 Oct 2004 01:19:07 +0000 Subject: 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) --- source4/ntvfs/common/opendb.c | 145 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 145 insertions(+) create mode 100644 source4/ntvfs/common/opendb.c (limited to 'source4/ntvfs/common') 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; +} -- cgit