From 4c185a6077322ba64231d23dda25a6b6d44d0b12 Mon Sep 17 00:00:00 2001 From: Volker Lendecke Date: Thu, 10 May 2007 10:42:13 +0000 Subject: r22775: For the cluster code I've developed a wrapper around tdb to put different database backends in place dynamically. The main abstractions are db_context and db_record, it should be mainly self-describing, see include/dbwrap.h. You open the db just as you would open a tdb, this time with db_open(). If you want to fetch a record, just do the db->fetch() call, if you want to do operations on it, you need to get it with fetch_locked(). I added dbwrap_file.c (not heavily tested lately) as an example for what can be done with that abstraction, uses a file per key. So if anybody is willing to shape that up, we might have a chance on reiserfs again.... :-) This abstraction works fine for brlock.tdb, locking.tdb, connections.tdb and sessionid.tdb. It should work fine for the others as well, I just did not yet get around to convert them. If nobody loudly screams NO, then I will import the code that uses this soon. Volker (This used to be commit e9d7484ca246cfca4a1fd23be35edc2783136ebe) --- source3/lib/dbwrap_tdb.c | 227 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 227 insertions(+) create mode 100644 source3/lib/dbwrap_tdb.c (limited to 'source3/lib/dbwrap_tdb.c') diff --git a/source3/lib/dbwrap_tdb.c b/source3/lib/dbwrap_tdb.c new file mode 100644 index 0000000000..238ba51761 --- /dev/null +++ b/source3/lib/dbwrap_tdb.c @@ -0,0 +1,227 @@ +/* + Unix SMB/CIFS implementation. + Database interface wrapper around tdb + Copyright (C) Volker Lendecke 2005-2007 + + 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. +*/ + +#include "includes.h" + +struct db_tdb_ctx { + TDB_CONTEXT *tdb; +}; + +static NTSTATUS db_tdb_store(struct db_record *rec, TDB_DATA data, int flag); +static NTSTATUS db_tdb_delete(struct db_record *rec); + +static int db_tdb_record_destr(struct db_record* data) +{ + struct db_tdb_ctx *ctx = + talloc_get_type_abort(data->private_data, struct db_tdb_ctx); + + DEBUG(10, ("Unlocking key %s\n", + hex_encode(data, (unsigned char *)data->key.dptr, + data->key.dsize))); + + if (tdb_chainunlock(ctx->tdb, data->key) != 0) { + DEBUG(0, ("tdb_chainunlock failed\n")); + return -1; + } + return 0; +} + +static struct db_record *db_tdb_fetch_locked(struct db_context *db, + TALLOC_CTX *mem_ctx, TDB_DATA key) +{ + struct db_tdb_ctx *ctx = talloc_get_type_abort(db->private_data, + struct db_tdb_ctx); + struct db_record *result; + TDB_DATA value; + + result = TALLOC_P(mem_ctx, struct db_record); + if (result == NULL) { + DEBUG(0, ("talloc failed\n")); + return NULL; + } + + result->key.dsize = key.dsize; + result->key.dptr = (uint8 *)talloc_memdup(result, key.dptr, key.dsize); + if (result->key.dptr == NULL) { + DEBUG(0, ("talloc failed\n")); + TALLOC_FREE(result); + return NULL; + } + + result->value.dptr = NULL; + result->value.dsize = 0; + result->private_data = talloc_reference(result, ctx); + result->store = db_tdb_store; + result->delete_rec = db_tdb_delete; + + { + char *keystr = hex_encode(NULL, (unsigned char *)key.dptr, + key.dsize); + DEBUG(10, ("Locking key %s\n", keystr)); + TALLOC_FREE(keystr); + } + + if (tdb_chainlock(ctx->tdb, key) != 0) { + DEBUG(3, ("tdb_chainlock failed\n")); + TALLOC_FREE(result); + return NULL; + } + + talloc_set_destructor(result, db_tdb_record_destr); + + value = tdb_fetch(ctx->tdb, key); + + if (value.dptr == NULL) { + return result; + } + + result->value.dsize = value.dsize; + result->value.dptr = (uint8 *)talloc_memdup(result, value.dptr, + value.dsize); + if (result->value.dptr == NULL) { + DEBUG(3, ("talloc failed\n")); + TALLOC_FREE(result); + return NULL; + } + + SAFE_FREE(value.dptr); + + DEBUG(10, ("Allocated locked data 0x%p\n", result)); + + return result; +} + +static NTSTATUS db_tdb_store(struct db_record *rec, TDB_DATA data, int flag) +{ + struct db_tdb_ctx *ctx = talloc_get_type_abort(rec->private_data, + struct db_tdb_ctx); + + /* + * This has a bug: We need to replace rec->value for correct + * operation, but right now brlock and locking don't use the value + * anymore after it was stored. + */ + + return (tdb_store(ctx->tdb, rec->key, data, flag) == 0) ? + NT_STATUS_OK : NT_STATUS_UNSUCCESSFUL; +} + +static NTSTATUS db_tdb_delete(struct db_record *rec) +{ + struct db_tdb_ctx *ctx = talloc_get_type_abort(rec->private_data, + struct db_tdb_ctx); + + return (tdb_delete(ctx->tdb, rec->key) == 0) ? + NT_STATUS_OK : NT_STATUS_UNSUCCESSFUL; +} + +struct db_tdb_traverse_ctx { + struct db_context *db; + int (*f)(struct db_record *rec, void *private_data); + void *private_data; +}; + +static int db_tdb_traverse_func(TDB_CONTEXT *tdb, TDB_DATA kbuf, TDB_DATA dbuf, + void *private_data) +{ + struct db_tdb_traverse_ctx *ctx = + (struct db_tdb_traverse_ctx *)private_data; + struct db_record rec; + + rec.key = kbuf; + rec.value = dbuf; + rec.store = db_tdb_store; + rec.delete_rec = db_tdb_delete; + rec.private_data = ctx->db->private_data; + + return ctx->f(&rec, ctx->private_data); +} + +static int db_tdb_traverse(struct db_context *db, + int (*f)(struct db_record *rec, void *private_data), + void *private_data) +{ + struct db_tdb_ctx *db_ctx = + talloc_get_type_abort(db->private_data, struct db_tdb_ctx); + struct db_tdb_traverse_ctx ctx; + + ctx.db = db; + ctx.f = f; + ctx.private_data = private_data; + return tdb_traverse(db_ctx->tdb, db_tdb_traverse_func, &ctx); +} + +static int db_tdb_get_seqnum(struct db_context *db) + +{ + struct db_tdb_ctx *db_ctx = + talloc_get_type_abort(db->private_data, struct db_tdb_ctx); + return tdb_get_seqnum(db_ctx->tdb); +} + +static int db_tdb_ctx_destr(struct db_tdb_ctx *ctx) +{ + if (tdb_close(ctx->tdb) != 0) { + DEBUG(0, ("Failed to close tdb: %s\n", strerror(errno))); + return -1; + } + + return 0; +} + +struct db_context *db_open_tdb(TALLOC_CTX *mem_ctx, + const char *name, + int hash_size, int tdb_flags, + int open_flags, mode_t mode) +{ + struct db_context *result = NULL; + struct db_tdb_ctx *db_tdb; + + result = TALLOC_ZERO_P(mem_ctx, struct db_context); + if (result == NULL) { + DEBUG(0, ("talloc failed\n")); + goto fail; + } + + result->private_data = db_tdb = TALLOC_P(result, struct db_tdb_ctx); + if (db_tdb == NULL) { + DEBUG(0, ("talloc failed\n")); + goto fail; + } + + db_tdb->tdb = tdb_open_log(name, hash_size, tdb_flags, + open_flags, mode); + if (db_tdb->tdb == NULL) { + DEBUG(3, ("Could not open tdb: %s\n", strerror(errno))); + goto fail; + } + + talloc_set_destructor(db_tdb, db_tdb_ctx_destr); + result->fetch_locked = db_tdb_fetch_locked; + result->traverse = db_tdb_traverse; + result->get_seqnum = db_tdb_get_seqnum; + return result; + + fail: + if (result != NULL) { + TALLOC_FREE(result); + } + return NULL; +} -- cgit