source: vendor/current/lib/dbwrap/dbwrap_tdb.c

/*
   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "dbwrap/dbwrap.h"
#include "dbwrap/dbwrap_private.h"
#include "dbwrap/dbwrap_tdb.h"
#include "lib/tdb_wrap/tdb_wrap.h"
#include "lib/util/util_tdb.h"
#include "system/filesys.h"
#include "lib/param/param.h"

struct db_tdb_ctx {
        struct tdb_wrap *wtdb;

        struct {
                dev_t dev;
                ino_t ino;
        } id;
};

static NTSTATUS db_tdb_store(struct db_record *rec, TDB_DATA data, int flag);
static NTSTATUS db_tdb_delete(struct db_record *rec);

static void db_tdb_log_key(const char *prefix, TDB_DATA key)
{
        size_t len;
        char *keystr;
        TALLOC_CTX *frame;
        if (DEBUGLEVEL < 10) {
                return;
        }
        frame = talloc_stackframe();
        len = key.dsize;
        if (DEBUGLEVEL == 10) {
                /*
                 * Only fully spam at debuglevel > 10
                 */
                len = MIN(10, key.dsize);
        }
        keystr = hex_encode_talloc(frame, (unsigned char *)(key.dptr),
                                   len);
        DEBUG(10, ("%s key %s\n", prefix, keystr));
        TALLOC_FREE(frame);
}

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);

        db_tdb_log_key("Unlocking", data->key);
        tdb_chainunlock(ctx->wtdb->tdb, data->key);
        return 0;
}

struct tdb_fetch_locked_state {
        TALLOC_CTX *mem_ctx;
        struct db_record *result;
};

static int db_tdb_fetchlock_parse(TDB_DATA key, TDB_DATA data,
                                  void *private_data)
{
        struct tdb_fetch_locked_state *state =
                (struct tdb_fetch_locked_state *)private_data;
        struct db_record *result;

        result = (struct db_record *)talloc_size(
                state->mem_ctx,
                sizeof(struct db_record) + key.dsize + data.dsize);

        if (result == NULL) {
                return 0;
        }
        state->result = result;

        result->key.dsize = key.dsize;
        result->key.dptr = ((uint8_t *)result) + sizeof(struct db_record);
        memcpy(result->key.dptr, key.dptr, key.dsize);

        result->value.dsize = data.dsize;

        if (data.dsize > 0) {
                result->value.dptr = result->key.dptr+key.dsize;
                memcpy(result->value.dptr, data.dptr, data.dsize);
        }
        else {
                result->value.dptr = NULL;
        }

        return 0;
}

static struct db_record *db_tdb_fetch_locked_internal(
        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 tdb_fetch_locked_state state;

        state.mem_ctx = mem_ctx;
        state.result = NULL;

        if ((tdb_parse_record(ctx->wtdb->tdb, key, db_tdb_fetchlock_parse,
                              &state) < 0) &&
            (tdb_error(ctx->wtdb->tdb) != TDB_ERR_NOEXIST)) {
                tdb_chainunlock(ctx->wtdb->tdb, key);
                return NULL;
        }

        if (state.result == NULL) {
                db_tdb_fetchlock_parse(key, tdb_null, &state);
        }

        if (state.result == NULL) {
                tdb_chainunlock(ctx->wtdb->tdb, key);
                return NULL;
        }

        talloc_set_destructor(state.result, db_tdb_record_destr);

        state.result->private_data = ctx;
        state.result->store = db_tdb_store;
        state.result->delete_rec = db_tdb_delete;

        DEBUG(10, ("Allocated locked data 0x%p\n", state.result));

        return state.result;
}

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);

        db_tdb_log_key("Locking", key);
        if (tdb_chainlock(ctx->wtdb->tdb, key) != 0) {
                DEBUG(3, ("tdb_chainlock failed\n"));
                return NULL;
        }
        return db_tdb_fetch_locked_internal(db, mem_ctx, key);
}

static struct db_record *db_tdb_try_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);

        db_tdb_log_key("Trying to lock", key);
        if (tdb_chainlock_nonblock(ctx->wtdb->tdb, key) != 0) {
                DEBUG(3, ("tdb_chainlock_nonblock failed\n"));
                return NULL;
        }
        return db_tdb_fetch_locked_internal(db, mem_ctx, key);
}


static int db_tdb_exists(struct db_context *db, TDB_DATA key)
{
        struct db_tdb_ctx *ctx = talloc_get_type_abort(
                db->private_data, struct db_tdb_ctx);
        return tdb_exists(ctx->wtdb->tdb, key);
}

static int db_tdb_wipe(struct db_context *db)
{
        struct db_tdb_ctx *ctx = talloc_get_type_abort(
                db->private_data, struct db_tdb_ctx);
        return tdb_wipe_all(ctx->wtdb->tdb);
}

static int db_tdb_check(struct db_context *db)
{
        struct db_tdb_ctx *ctx = talloc_get_type_abort(
                db->private_data, struct db_tdb_ctx);
        return tdb_check(ctx->wtdb->tdb, NULL, NULL);
}

struct db_tdb_parse_state {
        void (*parser)(TDB_DATA key, TDB_DATA data,
                       void *private_data);
        void *private_data;
};

/*
 * tdb_parse_record expects a parser returning int, mixing up tdb and
 * parser errors. Wrap around that by always returning 0 and have
 * dbwrap_parse_record expect a parser returning void.
 */

static int db_tdb_parser(TDB_DATA key, TDB_DATA data, void *private_data)
{
        struct db_tdb_parse_state *state =
                (struct db_tdb_parse_state *)private_data;
        state->parser(key, data, state->private_data);
        return 0;
}

static NTSTATUS db_tdb_parse(struct db_context *db, TDB_DATA key,
                             void (*parser)(TDB_DATA key, TDB_DATA data,
                                           void *private_data),
                             void *private_data)
{
        struct db_tdb_ctx *ctx = talloc_get_type_abort(
                db->private_data, struct db_tdb_ctx);
        struct db_tdb_parse_state state;
        int ret;

        state.parser = parser;
        state.private_data = private_data;

        ret = tdb_parse_record(ctx->wtdb->tdb, key, db_tdb_parser, &state);

        if (ret != 0) {
                return map_nt_error_from_tdb(tdb_error(ctx->wtdb->tdb));
        }
        return NT_STATUS_OK;
}

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->wtdb->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);

        if (tdb_delete(ctx->wtdb->tdb, rec->key) == 0) {
                return NT_STATUS_OK;
        }

        if (tdb_error(ctx->wtdb->tdb) == TDB_ERR_NOEXIST) {
                return NT_STATUS_NOT_FOUND;
        }

        return 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;
        rec.db = ctx->db;

        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->wtdb->tdb, db_tdb_traverse_func, &ctx);
}

static NTSTATUS db_tdb_store_deny(struct db_record *rec, TDB_DATA data, int flag)
{
        return NT_STATUS_MEDIA_WRITE_PROTECTED;
}

static NTSTATUS db_tdb_delete_deny(struct db_record *rec)
{
        return NT_STATUS_MEDIA_WRITE_PROTECTED;
}

static int db_tdb_traverse_read_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_deny;
        rec.delete_rec = db_tdb_delete_deny;
        rec.private_data = ctx->db->private_data;
        rec.db = ctx->db;

        return ctx->f(&rec, ctx->private_data);
}

static int db_tdb_traverse_read(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_read(db_ctx->wtdb->tdb, db_tdb_traverse_read_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->wtdb->tdb);
}

static int db_tdb_transaction_start(struct db_context *db)
{
        struct db_tdb_ctx *db_ctx =
                talloc_get_type_abort(db->private_data, struct db_tdb_ctx);
        return tdb_transaction_start(db_ctx->wtdb->tdb) ? -1 : 0;
}

static NTSTATUS db_tdb_transaction_start_nonblock(struct db_context *db)
{
        struct db_tdb_ctx *db_ctx =
                talloc_get_type_abort(db->private_data, struct db_tdb_ctx);
        int ret;

        ret = tdb_transaction_start_nonblock(db_ctx->wtdb->tdb);
        if (ret != 0) {
                return map_nt_error_from_tdb(tdb_error(db_ctx->wtdb->tdb));
        }
        return NT_STATUS_OK;
}

static int db_tdb_transaction_commit(struct db_context *db)
{
        struct db_tdb_ctx *db_ctx =
                talloc_get_type_abort(db->private_data, struct db_tdb_ctx);
        return tdb_transaction_commit(db_ctx->wtdb->tdb) ? -1 : 0;
}

static int db_tdb_transaction_cancel(struct db_context *db)
{
        struct db_tdb_ctx *db_ctx =
                talloc_get_type_abort(db->private_data, struct db_tdb_ctx);
        tdb_transaction_cancel(db_ctx->wtdb->tdb);
        return 0;
}

static size_t db_tdb_id(struct db_context *db, uint8_t *id, size_t idlen)
{
        struct db_tdb_ctx *db_ctx =
                talloc_get_type_abort(db->private_data, struct db_tdb_ctx);

        if (idlen >= sizeof(db_ctx->id)) {
                memcpy(id, &db_ctx->id, sizeof(db_ctx->id));
        }

        return sizeof(db_ctx->id);
}

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,
                               enum dbwrap_lock_order lock_order,
                               uint64_t dbwrap_flags)
{
        struct db_context *result = NULL;
        struct db_tdb_ctx *db_tdb;
        struct stat st;

        result = talloc_zero(mem_ctx, struct db_context);
        if (result == NULL) {
                DEBUG(0, ("talloc failed\n"));
                goto fail;
        }

        result->private_data = db_tdb = talloc(result, struct db_tdb_ctx);
        if (db_tdb == NULL) {
                DEBUG(0, ("talloc failed\n"));
                goto fail;
        }
        result->lock_order = lock_order;

        db_tdb->wtdb = tdb_wrap_open(db_tdb, name, hash_size, tdb_flags,
                                     open_flags, mode);
        if (db_tdb->wtdb == NULL) {
                DEBUG(3, ("Could not open tdb: %s\n", strerror(errno)));
                goto fail;
        }

        ZERO_STRUCT(db_tdb->id);

        if (fstat(tdb_fd(db_tdb->wtdb->tdb), &st) == -1) {
                DEBUG(3, ("fstat failed: %s\n", strerror(errno)));
                goto fail;
        }
        db_tdb->id.dev = st.st_dev;
        db_tdb->id.ino = st.st_ino;

        result->fetch_locked = db_tdb_fetch_locked;
        result->try_fetch_locked = db_tdb_try_fetch_locked;
        result->traverse = db_tdb_traverse;
        result->traverse_read = db_tdb_traverse_read;
        result->parse_record = db_tdb_parse;
        result->get_seqnum = db_tdb_get_seqnum;
        result->persistent = ((tdb_flags & TDB_CLEAR_IF_FIRST) == 0);
        result->transaction_start = db_tdb_transaction_start;
        result->transaction_start_nonblock = db_tdb_transaction_start_nonblock;
        result->transaction_commit = db_tdb_transaction_commit;
        result->transaction_cancel = db_tdb_transaction_cancel;
        result->exists = db_tdb_exists;
        result->wipe = db_tdb_wipe;
        result->id = db_tdb_id;
        result->check = db_tdb_check;
        result->name = tdb_name(db_tdb->wtdb->tdb);
        return result;

 fail:
        TALLOC_FREE(result);
        return NULL;
}