/*

   Unix SMB/CIFS implementation.

   Copyright (C) Stefan Metzmacher 2012

   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 "system/filesys.h"

#include "smbd/globals.h"

#include "dbwrap/dbwrap.h"

#include "dbwrap/dbwrap_open.h"

#include "lib/util/util_tdb.h"

#include "librpc/gen_ndr/ndr_smbXsrv.h"

#include "serverid.h"

/*

 * This implements a version scheme for file server internal

 * states. smbXsrv_version_global.tdb stores the possible

 * and current versions of structure formats (struct smbXsrv_*_global)

 * per cluster node.

 *

 * If the supported versions doesn't match a version of any

 * of the other nodes, it refused to start.

 *

 * This should prevent silent corruption of the internal

 * databases and structures, if two incompatible implementations

 * read and write.

 *

 * In future this can be used to implement rolling code upgrades

 * in a cluster, but for now it is simple.

 */

static struct db_context *smbXsrv_version_global_db_ctx = NULL;

static uint32_t smbXsrv_version_global_current_version = UINT32_MAX;

NTSTATUS smbXsrv_version_global_init(const struct server_id *server_id)

{

  const char *global_path = NULL;

  struct db_context *db_ctx = NULL;

  struct db_record *db_rec = NULL;

  TDB_DATA key;

  TDB_DATA val;

  DATA_BLOB blob;

  struct smbXsrv_version_globalB global_blob;

  enum ndr_err_code ndr_err;

  struct smbXsrv_version_global0 *global = NULL;

  uint32_t i;

  uint32_t num_valid = 0;

  struct smbXsrv_version_node0 *valid = NULL;

  struct smbXsrv_version_node0 *local_node = NULL;

  bool exists;

  NTSTATUS status;

  const char *key_string = "smbXsrv_version_global";

  TALLOC_CTX *frame;

  if (smbXsrv_version_global_db_ctx != NULL) {

    return NT_STATUS_OK;

  }

  frame = talloc_stackframe();

  global_path = lock_path(talloc_tos(), "smbXsrv_version_global.tdb");

  if (global_path == NULL) {

    TALLOC_FREE(frame);

    return NT_STATUS_NO_MEMORY;

  }

  db_ctx = db_open(NULL, global_path,

       0, /* hash_size */

       TDB_DEFAULT |

       TDB_CLEAR_IF_FIRST |

       TDB_INCOMPATIBLE_HASH,

       O_RDWR | O_CREAT, 0600,

       DBWRAP_LOCK_ORDER_1,

       DBWRAP_FLAG_NONE);

  if (db_ctx == NULL) {

    status = map_nt_error_from_unix_common(errno);

    DBG_ERR("failed to open[%s] - %s\n",

      global_path,

      nt_errstr(status));

    TALLOC_FREE(frame);

    return status;

  }

  key = string_term_tdb_data(key_string);

  db_rec = dbwrap_fetch_locked(db_ctx, db_ctx, key);

  if (db_rec == NULL) {

    status = NT_STATUS_INTERNAL_DB_ERROR;

    DBG_ERR("dbwrap_fetch_locked(%s) - %s\n",

      key_string,

      nt_errstr(status));

    TALLOC_FREE(frame);

    return status;

  }

  val = dbwrap_record_get_value(db_rec);

  if (val.dsize == 0) {

    global = talloc_zero(frame, struct smbXsrv_version_global0);

    if (global == NULL) {

      DBG_ERR("talloc_zero failed - %s\n", __location__);

      TALLOC_FREE(frame);

      return NT_STATUS_NO_MEMORY;

    }

    global_blob = (struct smbXsrv_version_globalB) {

      .version = SMBXSRV_VERSION_CURRENT,

      .info.info0 = global,

    };

  } else {

    blob = data_blob_const(val.dptr, val.dsize);

    ndr_err = ndr_pull_struct_blob(&blob, frame, &global_blob,

      (ndr_pull_flags_fn_t)ndr_pull_smbXsrv_version_globalB);

    if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {

      status = ndr_map_error2ntstatus(ndr_err);

      DBG_ERR("ndr_pull_smbXsrv_version_globalB - %s\n",

        nt_errstr(status));

      TALLOC_FREE(frame);

      return status;

    }

    switch (global_blob.version) {

    case SMBXSRV_VERSION_0:

      global = global_blob.info.info0;

      if (global == NULL) {

        status = NT_STATUS_INTERNAL_DB_CORRUPTION;

        break;

      }

      status = NT_STATUS_OK;

      break;

    default:

      status = NT_STATUS_REVISION_MISMATCH;

      break;

    }

    if (!NT_STATUS_IS_OK(status)) {

      DBG_ERR("%s\n", nt_errstr(status));

      NDR_PRINT_DEBUG(smbXsrv_version_globalB, &global_blob);

      TALLOC_FREE(frame);

      return status;

    }

  }

  valid = talloc_zero_array(global,

          struct smbXsrv_version_node0,

          global->num_nodes + 1);

  if (valid == NULL) {

    DBG_ERR("talloc_zero_array failed - %s\n", __location__);

    TALLOC_FREE(frame);

    return NT_STATUS_NO_MEMORY;

  }

  num_valid = 0;

  for (i=0; i < global->num_nodes; i++) {

    struct smbXsrv_version_node0 *n = &global->nodes[i];

    exists = serverid_exists(&n->server_id);

    if (!exists) {

      continue;

    }

    if (n->min_version > n->max_version) {

      status = NT_STATUS_INTERNAL_DB_CORRUPTION;

      DBG_ERR("%s\n", nt_errstr(status));

      NDR_PRINT_DEBUG(smbXsrv_version_globalB, &global_blob);

      TALLOC_FREE(frame);

      return status;

    }

    if (n->min_version > global_blob.version) {

      status = NT_STATUS_INTERNAL_DB_CORRUPTION;

      DBG_ERR("%s\n", nt_errstr(status));

      NDR_PRINT_DEBUG(smbXsrv_version_globalB, &global_blob);

      TALLOC_FREE(frame);

      return status;

    }

    if (n->max_version < global_blob.version) {

      status = NT_STATUS_INTERNAL_DB_CORRUPTION;

      DBG_ERR("%s\n", nt_errstr(status));

      NDR_PRINT_DEBUG(smbXsrv_version_globalB, &global_blob);

      TALLOC_FREE(frame);

      return status;

    }

    valid[num_valid] = *n;

    if (server_id->vnn == n->server_id.vnn) {

      local_node = &valid[num_valid];

    }

    num_valid++;

  }

  if (local_node == NULL) {

    local_node = &valid[num_valid];

    num_valid++;

  }

  *local_node = (struct smbXsrv_version_node0){

    .server_id = *server_id,

    .min_version = SMBXSRV_VERSION_0,

    .max_version = SMBXSRV_VERSION_CURRENT,

    .current_version = global_blob.version,

  };

  global->num_nodes = num_valid;

  global->nodes = valid;

  global_blob.seqnum += 1;

  global_blob.info.info0 = global;

  ndr_err = ndr_push_struct_blob(&blob, db_rec, &global_blob,

      (ndr_push_flags_fn_t)ndr_push_smbXsrv_version_globalB);

  if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {

    status = ndr_map_error2ntstatus(ndr_err);

    DBG_ERR("ndr_push_smbXsrv_version_globalB - %s\n",

      nt_errstr(status));

    TALLOC_FREE(frame);

    return status;

  }

  val = make_tdb_data(blob.data, blob.length);

  status = dbwrap_record_store(db_rec, val, TDB_REPLACE);

  TALLOC_FREE(db_rec);

  if (!NT_STATUS_IS_OK(status)) {

    DBG_ERR("dbwrap_record_store - %s\n", nt_errstr(status));

    TALLOC_FREE(frame);

    return status;

  }

  DBG_DEBUG("\n");

  if (DEBUGLVL(10)) {

    NDR_PRINT_DEBUG(smbXsrv_version_globalB, &global_blob);

  }

  smbXsrv_version_global_db_ctx = db_ctx;

  smbXsrv_version_global_current_version = global_blob.version;

  TALLOC_FREE(frame);

  return NT_STATUS_OK;

}

uint32_t smbXsrv_version_global_current(void)

{

  return smbXsrv_version_global_current_version;

}