/*

   Unix SMB/CIFS implementation.

   Database interface wrapper

   Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2006

   Major code contributions from Aleksey Fedoseev (fedoseev@ru.ibm.com)

   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 "replace.h"

#include "lib/util/debug.h"

#include "lib/util/fault.h"

#include "lib/util/talloc_stack.h"

#include "dbwrap/dbwrap.h"

#include "dbwrap/dbwrap_private.h"

#include "lib/util/util_tdb.h"

#include "lib/util/tevent_ntstatus.h"

/*

 * Fall back using fetch if no genuine exists operation is provided

 */

static int dbwrap_fallback_exists(struct db_context *db, TDB_DATA key)

{

  NTSTATUS status = dbwrap_parse_record(db, key, NULL, NULL);

  return NT_STATUS_IS_OK(status) ? 1 : 0;

}

static int delete_record(struct db_record *rec, void *data)

{

  NTSTATUS status = dbwrap_record_delete(rec);

  return NT_STATUS_IS_OK(status) ? 0 : -1;

}

/*

 * Fallback wipe implementation using traverse and delete if no genuine

 * wipe operation is provided

 */

static int dbwrap_fallback_wipe(struct db_context *db)

{

  NTSTATUS status = dbwrap_trans_traverse(db, delete_record, NULL);

  return NT_STATUS_IS_OK(status) ? 0 : -1;

}

static int do_nothing(struct db_record *rec, void *unused)

{

  return 0;

}

/*

 * Fallback check operation: just traverse.

 */

static int dbwrap_fallback_check(struct db_context *db)

{

  NTSTATUS status = dbwrap_traverse_read(db, do_nothing, NULL, NULL);

  return NT_STATUS_IS_OK(status) ? 0 : -1;

}

/*

 * Wrapper functions for the backend methods

 */

TDB_DATA dbwrap_record_get_key(const struct db_record *rec)

{

  return rec->key;

}

TDB_DATA dbwrap_record_get_value(const struct db_record *rec)

{

  SMB_ASSERT(rec->value_valid);

  return rec->value;

}

NTSTATUS dbwrap_record_storev(struct db_record *rec,

            const TDB_DATA *dbufs, int num_dbufs, int flags)

{

  NTSTATUS status;

  /*

   * Invalidate before rec->storev() is called, give

   * rec->storev() the chance to re-validate rec->value.

   */

  rec->value_valid = false;

  status = rec->storev(rec, dbufs, num_dbufs, flags);

  if (!NT_STATUS_IS_OK(status)) {

    return status;

  }

  return NT_STATUS_OK;

}

NTSTATUS dbwrap_record_store(struct db_record *rec, TDB_DATA data, int flags)

{

  return dbwrap_record_storev(rec, &data, 1, flags);

}

NTSTATUS dbwrap_record_delete(struct db_record *rec)

{

  NTSTATUS status;

  status = rec->delete_rec(rec);

  if (!NT_STATUS_IS_OK(status)) {

    return status;

  }

  rec->value = tdb_null;

  return NT_STATUS_OK;

}

struct dbwrap_merge_dbs_state {

  struct db_context *to;

  int flags;

};

/* Copy a single record to the db_context passed in private_data */

static int dbwrap_merge_dbs_copy_record(struct db_record *rec,

              void *private_data)

{

  struct dbwrap_merge_dbs_state *state = private_data;

  TDB_DATA data = dbwrap_record_get_value(rec);

  TDB_DATA key = dbwrap_record_get_key(rec);

  NTSTATUS status = dbwrap_store(state->to, key, data, state->flags);

  return NT_STATUS_IS_OK(status) ? 0 : 1;

}

NTSTATUS

dbwrap_merge_dbs(struct db_context *to, struct db_context *from, int flags)

{

  struct dbwrap_merge_dbs_state state = {.to = to, .flags = flags};

  return dbwrap_traverse(from,

             dbwrap_merge_dbs_copy_record,

             &state,

             NULL);

}

const char *locked_dbs[DBWRAP_LOCK_ORDER_MAX];

static const char *lock_order_dbg(void)

{

  int i;

  char *msg = talloc_strdup(talloc_tos(), "lock order:");

  for (i = 0; i < DBWRAP_LOCK_ORDER_MAX; i++) {

    talloc_asprintf_addbuf(

      &msg,

      " %d:%s",

      i + 1,

      locked_dbs[i] != NULL ? locked_dbs[i] : "<none>");

  }

  if (msg == NULL) {

    return "lock order: <out of memory>\n";

  }

  return msg;

}

void dbwrap_lock_order_lock(const char *db_name,

          enum dbwrap_lock_order lock_order)

{

  int idx;

  DBG_INFO("check lock order %d for %s\n",

     (int)lock_order,

     db_name);

  if (!DBWRAP_LOCK_ORDER_VALID(lock_order)) {

    DBG_ERR("Invalid lock order %d of %s\n",

      lock_order,

      db_name);

    smb_panic("lock order violation");

  }

  for (idx=lock_order-1; idx<DBWRAP_LOCK_ORDER_MAX; idx++) {

    if (locked_dbs[idx] != NULL) {

      DBG_ERR("Lock order violation: Trying %s at %d while "

        "%s at %d is locked\n%s\n",

        db_name,

        (int)lock_order,

        locked_dbs[idx],

        idx + 1,

        lock_order_dbg());

      smb_panic("lock order violation");

    }

  }

  locked_dbs[lock_order-1] = db_name;

  DBG_DEBUG("%s\n", lock_order_dbg());

}

void dbwrap_lock_order_unlock(const char *db_name,

            enum dbwrap_lock_order lock_order)

{

  DBG_INFO("release lock order %d for %s\n",

     (int)lock_order,

     db_name);

  if (!DBWRAP_LOCK_ORDER_VALID(lock_order)) {

    DBG_ERR("Invalid lock order %d of %s\n",

      lock_order,

      db_name);

    smb_panic("lock order violation");

  }

  if (locked_dbs[lock_order-1] == NULL) {

    DBG_ERR("db %s at order %d unlocked\n",

      db_name,

      (int)lock_order);

    smb_panic("lock order violation");

  }

  if (locked_dbs[lock_order-1] != db_name) {

    DBG_ERR("locked db at lock order %d is %s, expected %s\n",

      (int)lock_order,

      locked_dbs[lock_order-1],

      db_name);

    smb_panic("lock order violation");

  }

  locked_dbs[lock_order-1] = NULL;

}

struct dbwrap_lock_order_state {

  struct db_context *db;

};

static int dbwrap_lock_order_state_destructor(

  struct dbwrap_lock_order_state *s)

{

  struct db_context *db = s->db;

  dbwrap_lock_order_unlock(db->name, db->lock_order);

  return 0;

}

static struct dbwrap_lock_order_state *dbwrap_check_lock_order(

  struct db_context *db, TALLOC_CTX *mem_ctx)

{

  struct dbwrap_lock_order_state *state;

  state = talloc(mem_ctx, struct dbwrap_lock_order_state);

  if (state == NULL) {

    DBG_WARNING("talloc failed\n");

    return NULL;

  }

  state->db = db;

  dbwrap_lock_order_lock(db->name, db->lock_order);

  talloc_set_destructor(state, dbwrap_lock_order_state_destructor);

  return state;

}

static struct db_record *dbwrap_fetch_locked_internal(

  struct db_context *db, TALLOC_CTX *mem_ctx, TDB_DATA key,

  struct db_record *(*db_fn)(struct db_context *db, TALLOC_CTX *mem_ctx,

           TDB_DATA key))

{

  struct db_record *rec;

  struct dbwrap_lock_order_state *lock_order = NULL;

  if (db->lock_order != DBWRAP_LOCK_ORDER_NONE) {

    lock_order = dbwrap_check_lock_order(db, mem_ctx);

    if (lock_order == NULL) {

      return NULL;

    }

  }

  rec = db_fn(db, mem_ctx, key);

  if (rec == NULL) {

    TALLOC_FREE(lock_order);

    return NULL;

  }

  (void)talloc_steal(rec, lock_order);

  rec->db = db;

  return rec;

}

struct db_record *dbwrap_fetch_locked(struct db_context *db,

              TALLOC_CTX *mem_ctx,

              TDB_DATA key)

{

  return dbwrap_fetch_locked_internal(db, mem_ctx, key,

              db->fetch_locked);

}

struct db_context *dbwrap_record_get_db(struct db_record *rec)

{

  return rec->db;

}

struct dbwrap_fetch_state {

  TALLOC_CTX *mem_ctx;

  TDB_DATA data;

};

static void dbwrap_fetch_parser(TDB_DATA key, TDB_DATA data,

        void *private_data)

{

  struct dbwrap_fetch_state *state =

    (struct dbwrap_fetch_state *)private_data;

  state->data.dsize = data.dsize;

  state->data.dptr = (uint8_t *)talloc_memdup(state->mem_ctx, data.dptr,

                data.dsize);

}

NTSTATUS dbwrap_fetch(struct db_context *db, TALLOC_CTX *mem_ctx,

          TDB_DATA key, TDB_DATA *value)

{

  struct dbwrap_fetch_state state;

  NTSTATUS status;

  if (value == NULL) {

    return NT_STATUS_INVALID_PARAMETER;

  }

  state.mem_ctx = mem_ctx;

  status = dbwrap_parse_record(db, key, dbwrap_fetch_parser, &state);

  if (!NT_STATUS_IS_OK(status)) {

    return status;

  }

  if ((state.data.dsize != 0) && (state.data.dptr == NULL)) {

    return NT_STATUS_NO_MEMORY;

  }

  *value = state.data;

  return NT_STATUS_OK;

}

bool dbwrap_exists(struct db_context *db, TDB_DATA key)

{

  int result;

  if (db->exists != NULL) {

    result = db->exists(db, key);

  } else {

    result = dbwrap_fallback_exists(db,key);

  }

  return (result == 1);

}

struct dbwrap_store_state {

  TDB_DATA data;

  int flags;

  NTSTATUS status;

};

static void dbwrap_store_fn(

  struct db_record *rec,

  TDB_DATA value,

  void *private_data)

{

  struct dbwrap_store_state *state = private_data;

  state->status = dbwrap_record_store(rec, state->data, state->flags);

}

NTSTATUS dbwrap_store(struct db_context *db, TDB_DATA key,

          TDB_DATA data, int flags)

{

  struct dbwrap_store_state state = { .data = data, .flags = flags };

  NTSTATUS status;

  status = dbwrap_do_locked(db, key, dbwrap_store_fn, &state);

  if (!NT_STATUS_IS_OK(status)) {

    return status;

  }

  return state.status;

}

struct dbwrap_delete_state {

  NTSTATUS status;

};

static void dbwrap_delete_fn(

  struct db_record *rec,

  TDB_DATA value,

  void *private_data)

{

  struct dbwrap_delete_state *state = private_data;

  state->status = dbwrap_record_delete(rec);

}

NTSTATUS dbwrap_delete(struct db_context *db, TDB_DATA key)

{

  struct dbwrap_delete_state state = { .status = NT_STATUS_NOT_FOUND };

  NTSTATUS status;

  status = dbwrap_do_locked(db, key, dbwrap_delete_fn, &state);

  if (!NT_STATUS_IS_OK(status)) {

    return status;

  }

  return state.status;

}

NTSTATUS dbwrap_traverse(struct db_context *db,

       int (*f)(struct db_record*, void*),

       void *private_data,

       int *count)

{

  int ret = db->traverse(db, f, private_data);

  if (ret < 0) {

    return NT_STATUS_INTERNAL_DB_CORRUPTION;

  }

  if (count != NULL) {

    *count = ret;

  }

  return NT_STATUS_OK;

}

NTSTATUS dbwrap_traverse_read(struct db_context *db,

            int (*f)(struct db_record*, void*),

            void *private_data,

            int *count)

{

  int ret = db->traverse_read(db, f, private_data);

  if (ret < 0) {

    return NT_STATUS_INTERNAL_DB_CORRUPTION;

  }

  if (count != NULL) {

    *count = ret;

  }

  return NT_STATUS_OK;

}

static void dbwrap_null_parser(TDB_DATA key, TDB_DATA val, void* data)

{

  return;

}

NTSTATUS dbwrap_parse_record(struct db_context *db, TDB_DATA key,

           void (*parser)(TDB_DATA key, TDB_DATA data,

              void *private_data),

           void *private_data)

{

  if (parser == NULL) {

    parser = dbwrap_null_parser;

  }

  return db->parse_record(db, key, parser, private_data);

}

struct dbwrap_parse_record_state {

  struct db_context *db;

  TDB_DATA key;

  uint8_t _keybuf[64];

};

static void dbwrap_parse_record_done(struct tevent_req *subreq);

struct tevent_req *dbwrap_parse_record_send(

  TALLOC_CTX *mem_ctx,

  struct tevent_context *ev,

  struct db_context *db,

  TDB_DATA key,

  void (*parser)(TDB_DATA key, TDB_DATA data, void *private_data),

  void *private_data,

  enum dbwrap_req_state *req_state)

{

  struct tevent_req *req = NULL;

  struct tevent_req *subreq = NULL;

  struct dbwrap_parse_record_state *state = NULL;

  NTSTATUS status;

  req = tevent_req_create(mem_ctx, &state, struct dbwrap_parse_record_state);

  if (req == NULL) {

    *req_state = DBWRAP_REQ_ERROR;

    return NULL;

  }

  *state = (struct dbwrap_parse_record_state) {

    .db = db,

  };

  if (parser == NULL) {

    parser = dbwrap_null_parser;

  }

  *req_state = DBWRAP_REQ_INIT;

  if (db->parse_record_send == NULL) {

    /*

     * Backend doesn't implement async version, call sync one

     */

    status = db->parse_record(db, key, parser, private_data);

    if (tevent_req_nterror(req, status)) {

      *req_state = DBWRAP_REQ_DONE;

      return tevent_req_post(req, ev);

    }

    *req_state = DBWRAP_REQ_DONE;

    tevent_req_done(req);

    return tevent_req_post(req, ev);

  }

  /*

   * Copy the key into our state ensuring the key data buffer is always

   * available to all the dbwrap backends over the entire lifetime of the

   * async request. Otherwise the caller might have free'd the key buffer.

   */

  if (key.dsize > sizeof(state->_keybuf)) {

    state->key.dptr = talloc_memdup(state, key.dptr, key.dsize);

    if (tevent_req_nomem(state->key.dptr, req)) {

      return tevent_req_post(req, ev);

    }

  } else {

    memcpy(state->_keybuf, key.dptr, key.dsize);

    state->key.dptr = state->_keybuf;

  }

  state->key.dsize = key.dsize;

  subreq = db->parse_record_send(state,

               ev,

               db,

               state->key,

               parser,

               private_data,

               req_state);

  if (tevent_req_nomem(subreq, req)) {

    *req_state = DBWRAP_REQ_ERROR;

    return tevent_req_post(req, ev);

  }

  tevent_req_set_callback(subreq,

        dbwrap_parse_record_done,

        req);

  return req;

}

static void dbwrap_parse_record_done(struct tevent_req *subreq)

{

  struct tevent_req *req = tevent_req_callback_data(

    subreq, struct tevent_req);

  struct dbwrap_parse_record_state *state = tevent_req_data(

    req, struct dbwrap_parse_record_state);

  NTSTATUS status;

  status = state->db->parse_record_recv(subreq);

  TALLOC_FREE(subreq);

  if (!NT_STATUS_IS_OK(status)) {

    tevent_req_nterror(req, status);

    return;

  }

  tevent_req_done(req);

}

NTSTATUS dbwrap_parse_record_recv(struct tevent_req *req)

{

  return tevent_req_simple_recv_ntstatus(req);

}

NTSTATUS dbwrap_do_locked(struct db_context *db, TDB_DATA key,

        void (*fn)(struct db_record *rec,

             TDB_DATA value,

             void *private_data),

        void *private_data)

{

  struct db_record *rec;

  if (db->do_locked != NULL) {

    NTSTATUS status;

    if (db->lock_order != DBWRAP_LOCK_ORDER_NONE) {

      dbwrap_lock_order_lock(db->name, db->lock_order);

    }

    status = db->do_locked(db, key, fn, private_data);

    if (db->lock_order != DBWRAP_LOCK_ORDER_NONE) {

      dbwrap_lock_order_unlock(db->name, db->lock_order);

    }

    return status;

  }

  rec = dbwrap_fetch_locked(db, db, key);

  if (rec == NULL) {

    return NT_STATUS_NO_MEMORY;

  }

  /*

   * Invalidate rec->value, nobody shall assume it's set from

   * within dbwrap_do_locked().

   */

  rec->value_valid = false;

  fn(rec, rec->value, private_data);

  TALLOC_FREE(rec);

  return NT_STATUS_OK;

}

int dbwrap_wipe(struct db_context *db)

{

  if (db->wipe == NULL) {

    return dbwrap_fallback_wipe(db);

  }

  return db->wipe(db);

}

int dbwrap_check(struct db_context *db)

{

  if (db->check == NULL) {

    return dbwrap_fallback_check(db);

  }

  return db->check(db);

}

int dbwrap_get_seqnum(struct db_context *db)

{

  return db->get_seqnum(db);

}

int dbwrap_transaction_start(struct db_context *db)

{

  if (!db->persistent) {

    /*

     * dbwrap_ctdb has two different data models for persistent

     * and non-persistent databases. Transactions are supported

     * only for the persistent databases. This check is here to

     * prevent breakages of the cluster case, autobuild at this

     * point only tests non-clustered Samba. Before removing this

     * check, please make sure that this facility has also been

     * added to dbwrap_ctdb.

     *

     * Thanks, vl

     */

    DEBUG(1, ("transactions not supported on non-persistent "

        "database %s\n", db->name));

    return -1;

  }

  return db->transaction_start(db);

}

NTSTATUS dbwrap_transaction_start_nonblock(struct db_context *db)

{

  if (db->transaction_start_nonblock) {

    return db->transaction_start_nonblock(db);

  } else {

    return dbwrap_transaction_start(db) == 0 ? NT_STATUS_OK

      : NT_STATUS_UNSUCCESSFUL;

  }

}

int dbwrap_transaction_commit(struct db_context *db)

{

  return db->transaction_commit(db);

}

int dbwrap_transaction_cancel(struct db_context *db)

{

  return db->transaction_cancel(db);

}

size_t dbwrap_db_id(struct db_context *db, uint8_t *id, size_t idlen)

{

  return db->id(db, id, idlen);

}

bool dbwrap_is_persistent(struct db_context *db)

{

  return db->persistent;

}

const char *dbwrap_name(struct db_context *db)

{

  return db->name;

}

static ssize_t tdb_data_buf(const TDB_DATA *dbufs, int num_dbufs,

          uint8_t *buf, size_t buflen)

{

  size_t needed = 0;

  uint8_t *p = buf;

  int i;

  for (i=0; i<num_dbufs; i++) {

    size_t thislen = dbufs[i].dsize;

    needed += thislen;

    if (needed < thislen) {

      /* wrap */

      return -1;

    }

    if (p != NULL && (thislen != 0) && (needed <= buflen)) {

      memcpy(p, dbufs[i].dptr, thislen);

      p += thislen;

    }

  }

  return needed;

}

NTSTATUS dbwrap_merge_dbufs(TDB_DATA *buf, TALLOC_CTX *mem_ctx,

          const TDB_DATA *dbufs, int num_dbufs)

{

  ssize_t len = tdb_data_buf(dbufs, num_dbufs, NULL, 0);

  if (len == -1) {

    return NT_STATUS_INVALID_PARAMETER;

  }

  if (buf->dsize != len) {

    uint8_t *tmp;

    tmp = talloc_realloc(mem_ctx, buf->dptr, uint8_t, len);

    if (tmp == NULL && len != 0) {

      return NT_STATUS_NO_MEMORY;

    }

    buf->dptr = tmp;

    buf->dsize = len;

  }

  tdb_data_buf(dbufs, num_dbufs, buf->dptr, buf->dsize);

  return NT_STATUS_OK;

}