/*

   Unix SMB/CIFS implementation.

   trivial database library

   Copyright (C) Andrew Tridgell              1999-2005

   Copyright (C) Paul `Rusty' Russell      2000

   Copyright (C) Jeremy Allison        2000-2003

     ** NOTE! The following LGPL license applies to the tdb

     ** library. This does NOT imply that all of Samba is released

     ** under the LGPL

   This library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 3 of the License, or (at your option) any later version.

   This library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with this library; if not, see <http://www.gnu.org/licenses/>.

*/

#include "tdb_private.h"

/* all contexts, to ensure no double-opens (fcntl locks don't nest!) */

static struct tdb_context *tdbs = NULL;

/* We use two hashes to double-check they're using the right hash function. */

void tdb_header_hash(struct tdb_context *tdb,

         uint32_t *magic1_hash, uint32_t *magic2_hash)

{

  TDB_DATA hash_key;

  uint32_t tdb_magic = TDB_MAGIC;

  hash_key.dptr = discard_const_p(unsigned char, TDB_MAGIC_FOOD);

  hash_key.dsize = sizeof(TDB_MAGIC_FOOD);

  *magic1_hash = tdb->hash_fn(&hash_key);

  hash_key.dptr = (unsigned char *)CONVERT(tdb_magic);

  hash_key.dsize = sizeof(tdb_magic);

  *magic2_hash = tdb->hash_fn(&hash_key);

  /* Make sure at least one hash is non-zero! */

  if (*magic1_hash == 0 && *magic2_hash == 0)

    *magic1_hash = 1;

}

/* initialise a new database with a specified hash size */

static int tdb_new_database(struct tdb_context *tdb, struct tdb_header *header,

          int hash_size)

{

  struct tdb_header *newdb;

  size_t size;

  int ret = -1;

  /* We make it up in memory, then write it out if not internal */

  size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off_t);

  if (!(newdb = (struct tdb_header *)calloc(size, 1))) {

    tdb->ecode = TDB_ERR_OOM;

    return -1;

  }

  /* Fill in the header */

  newdb->version = TDB_VERSION;

  newdb->hash_size = hash_size;

  tdb_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash);

  /* Make sure older tdbs (which don't check the magic hash fields)

   * will refuse to open this TDB. */

  if (tdb->flags & TDB_INCOMPATIBLE_HASH)

    newdb->rwlocks = TDB_HASH_RWLOCK_MAGIC;

  /*

   * We create a tdb with TDB_FEATURE_FLAG_MUTEX support,

   * the flag combination and runtime feature checks

   * are done by the caller already.

   */

  if (tdb->flags & TDB_MUTEX_LOCKING) {

    newdb->feature_flags |= TDB_FEATURE_FLAG_MUTEX;

  }

  /*

   * If we have any features we add the FEATURE_FLAG_MAGIC, overwriting the

   * TDB_HASH_RWLOCK_MAGIC above.

   */

  if (newdb->feature_flags != 0) {

    newdb->rwlocks = TDB_FEATURE_FLAG_MAGIC;

  }

  /*

   * It's required for some following code paths

   * to have the fields on 'tdb' up-to-date.

   *

   * E.g. tdb_mutex_size() requires it

   */

  tdb->feature_flags = newdb->feature_flags;

  tdb->hash_size = newdb->hash_size;

  if (tdb->flags & TDB_INTERNAL) {

    tdb->map_size = size;

    tdb->map_ptr = (char *)newdb;

    memcpy(header, newdb, sizeof(*header));

    /* Convert the `ondisk' version if asked. */

    CONVERT(*newdb);

    return 0;

  }

  if (lseek(tdb->fd, 0, SEEK_SET) == -1)

    goto fail;

  if (ftruncate(tdb->fd, 0) == -1)

    goto fail;

  if (newdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {

    newdb->mutex_size = tdb_mutex_size(tdb);

    tdb->hdr_ofs = newdb->mutex_size;

  }

  /* This creates an endian-converted header, as if read from disk */

  CONVERT(*newdb);

  memcpy(header, newdb, sizeof(*header));

  /* Don't endian-convert the magic food! */

  memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1);

  if (!tdb_write_all(tdb->fd, newdb, size))

    goto fail;

  if (newdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {

    /*

     * Now we init the mutex area

     * followed by a second header.

     */

    ret = ftruncate(

      tdb->fd,

      newdb->mutex_size + sizeof(struct tdb_header));

    if (ret == -1) {

      goto fail;

    }

    ret = tdb_mutex_init(tdb);

    if (ret == -1) {

      goto fail;

    }

    /*

     * Write a second header behind the mutexes. That's the area

     * that will be mmapp'ed.

     */

    ret = lseek(tdb->fd, newdb->mutex_size, SEEK_SET);

    if (ret == -1) {

      goto fail;

    }

    if (!tdb_write_all(tdb->fd, newdb, size)) {

      goto fail;

    }

  }

  ret = 0;

  fail:

  SAFE_FREE(newdb);

  return ret;

}

static int tdb_already_open(dev_t device,

          ino_t ino)

{

  struct tdb_context *i;

  for (i = tdbs; i; i = i->next) {

    if (i->device == device && i->inode == ino) {

      return 1;

    }

  }

  return 0;

}

/* open the database, creating it if necessary

   The open_flags and mode are passed straight to the open call on the

   database file. A flags value of O_WRONLY is invalid. The hash size

   is advisory, use zero for a default value.

   Return is NULL on error, in which case errno is also set.  Don't

   try to call tdb_error or tdb_errname, just do strerror(errno).

   @param name may be NULL for internal databases. */

_PUBLIC_ struct tdb_context *tdb_open(const char *name, int hash_size, int tdb_flags,

          int open_flags, mode_t mode)

{

  return tdb_open_ex(name, hash_size, tdb_flags, open_flags, mode, NULL, NULL);

}

/* a default logging function */

static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);

static void null_log_fn(struct tdb_context *tdb, enum tdb_debug_level level, const char *fmt, ...)

{

}

static bool check_header_hash(struct tdb_context *tdb,

            struct tdb_header *header,

            bool default_hash, uint32_t *m1, uint32_t *m2)

{

  tdb_header_hash(tdb, m1, m2);

  if (header->magic1_hash == *m1 &&

      header->magic2_hash == *m2) {

    return true;

  }

  /* If they explicitly set a hash, always respect it. */

  if (!default_hash)

    return false;

  /* Otherwise, try the other inbuilt hash. */

  if (tdb->hash_fn == tdb_old_hash)

    tdb->hash_fn = tdb_jenkins_hash;

  else

    tdb->hash_fn = tdb_old_hash;

  return check_header_hash(tdb, header, false, m1, m2);

}

static bool tdb_mutex_open_ok(struct tdb_context *tdb,

            const struct tdb_header *header)

{

  if (tdb->flags & TDB_NOLOCK) {

    /*

     * We don't look at locks, so it does not matter to have a

     * compatible mutex implementation. Allow the open.

     */

    return true;

  }

  if (!(tdb->flags & TDB_MUTEX_LOCKING)) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok[%s]: "

       "Can use mutexes only with "

       "MUTEX_LOCKING or NOLOCK\n",

       tdb->name));

    return false;

  }

  if (tdb_mutex_size(tdb) != header->mutex_size) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_mutex_open_ok[%s]: "

       "Mutex size changed from %"PRIu32" to %zu\n.",

       tdb->name,

       header->mutex_size,

       tdb_mutex_size(tdb)));

    return false;

  }

  return true;

}

_PUBLIC_ struct tdb_context *tdb_open_ex(const char *name, int hash_size, int tdb_flags,

        int open_flags, mode_t mode,

        const struct tdb_logging_context *log_ctx,

        tdb_hash_func hash_fn)

{

  int orig_errno = errno;

  struct tdb_header header = {

    .version = 0,

  };

  struct tdb_context *tdb;

  struct stat st;

  int rev = 0;

  bool locked = false;

  unsigned char *vp;

  uint32_t vertest;

  unsigned v;

  const char *hash_alg;

  uint32_t magic1, magic2;

  int ret;

  if (!(tdb = (struct tdb_context *)calloc(1, sizeof *tdb))) {

    /* Can't log this */

    errno = ENOMEM;

    goto fail;

  }

  tdb_io_init(tdb);

  if (tdb_flags & TDB_INTERNAL) {

    tdb_flags |= TDB_INCOMPATIBLE_HASH;

  }

  if (tdb_flags & TDB_MUTEX_LOCKING) {

    tdb_flags |= TDB_INCOMPATIBLE_HASH;

  }

  tdb->fd = -1;

#ifdef TDB_TRACE

  tdb->tracefd = -1;

#endif

  tdb->name = NULL;

  tdb->map_ptr = NULL;

  tdb->flags = tdb_flags;

  tdb->open_flags = open_flags;

  if (log_ctx) {

    tdb->log = *log_ctx;

  } else {

    tdb->log.log_fn = null_log_fn;

    tdb->log.log_private = NULL;

  }

  if (name == NULL && (tdb_flags & TDB_INTERNAL)) {

    name = "__TDB_INTERNAL__";

  }

  if (name == NULL) {

    tdb->name = discard_const_p(char, "__NULL__");

    TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: called with name == NULL\n"));

    tdb->name = NULL;

    errno = EINVAL;

    goto fail;

  }

  /* now make a copy of the name, as the caller memory might go away */

  if (!(tdb->name = (char *)strdup(name))) {

    /*

     * set the name as the given string, so that tdb_name() will

     * work in case of an error.

     */

    tdb->name = discard_const_p(char, name);

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't strdup(%s)\n",

       name));

    tdb->name = NULL;

    errno = ENOMEM;

    goto fail;

  }

  if (hash_fn) {

    tdb->hash_fn = hash_fn;

    hash_alg = "the user defined";

  } else {

    /* This controls what we use when creating a tdb. */

    if (tdb->flags & TDB_INCOMPATIBLE_HASH) {

      tdb->hash_fn = tdb_jenkins_hash;

    } else {

      tdb->hash_fn = tdb_old_hash;

    }

    hash_alg = "either default";

  }

  /* cache the page size */

  tdb->page_size = getpagesize();

  if (tdb->page_size <= 0) {

    tdb->page_size = 0x2000;

  }

  tdb->max_dead_records = (tdb_flags & TDB_VOLATILE) ? 5 : 0;

  if ((open_flags & O_ACCMODE) == O_WRONLY) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: can't open tdb %s write-only\n",

       name));

    errno = EINVAL;

    goto fail;

  }

  if (hash_size == 0)

    hash_size = DEFAULT_HASH_SIZE;

  if ((open_flags & O_ACCMODE) == O_RDONLY) {

    tdb->read_only = 1;

    /* read only databases don't do locking or clear if first */

    tdb->flags |= TDB_NOLOCK;

    tdb->flags &= ~(TDB_CLEAR_IF_FIRST|TDB_MUTEX_LOCKING);

  }

  if ((tdb->flags & TDB_ALLOW_NESTING) &&

      (tdb->flags & TDB_DISALLOW_NESTING)) {

    tdb->ecode = TDB_ERR_NESTING;

    TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "

      "allow_nesting and disallow_nesting are not allowed together!"));

    errno = EINVAL;

    goto fail;

  }

  if (tdb->flags & TDB_MUTEX_LOCKING) {

    /*

     * Here we catch bugs in the callers,

     * the runtime check for existing tdb's comes later.

     */

    if (tdb->flags & TDB_INTERNAL) {

      TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "

        "invalid flags for %s - TDB_MUTEX_LOCKING and "

        "TDB_INTERNAL are not allowed together\n", name));

      errno = EINVAL;

      goto fail;

    }

    if (tdb->flags & TDB_NOMMAP) {

      TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "

        "invalid flags for %s - TDB_MUTEX_LOCKING and "

        "TDB_NOMMAP are not allowed together\n", name));

      errno = EINVAL;

      goto fail;

    }

    if (tdb->read_only) {

      TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "

        "invalid flags for %s - TDB_MUTEX_LOCKING "

        "not allowed read only\n", name));

      errno = EINVAL;

      goto fail;

    }

    /*

     * The callers should have called

     * tdb_runtime_check_for_robust_mutexes()

     * before using TDB_MUTEX_LOCKING!

     *

     * This makes sure the caller understands

     * that the locking may behave a bit differently

     * than with pure fcntl locking. E.g. multiple

     * read locks are not supported.

     */

    if (!tdb_runtime_check_for_robust_mutexes()) {

      TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "

        "invalid flags for %s - TDB_MUTEX_LOCKING "

        "requires support for robust_mutexes\n",

        name));

      errno = ENOSYS;

      goto fail;

    }

  }

  if (getenv("TDB_NO_FSYNC")) {

    tdb->flags |= TDB_NOSYNC;

  }

  /*

   * TDB_ALLOW_NESTING is the default behavior.

   * Note: this may change in future versions!

   */

  if (!(tdb->flags & TDB_DISALLOW_NESTING)) {

    tdb->flags |= TDB_ALLOW_NESTING;

  }

  /* internal databases don't mmap or lock, and start off cleared */

  if (tdb->flags & TDB_INTERNAL) {

    tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);

    tdb->flags &= ~TDB_CLEAR_IF_FIRST;

    if (tdb_new_database(tdb, &header, hash_size) != 0) {

      TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: tdb_new_database failed!"));

      goto fail;

    }

    tdb->hash_size = hash_size;

    goto internal;

  }

  if ((tdb->fd = open(name, open_flags, mode)) == -1) {

    TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_open_ex: could not open file %s: %s\n",

       name, strerror(errno)));

    goto fail;  /* errno set by open(2) */

  }

  /* on exec, don't inherit the fd */

  v = fcntl(tdb->fd, F_GETFD, 0);

        fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);

  /* ensure there is only one process initialising at once */

  if (tdb_nest_lock(tdb, OPEN_LOCK, F_WRLCK, TDB_LOCK_WAIT) == -1) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to get open lock on %s: %s\n",

       name, strerror(errno)));

    goto fail;  /* errno set by tdb_brlock */

  }

  /* we need to zero database if we are the only one with it open */

  if ((tdb_flags & TDB_CLEAR_IF_FIRST) &&

      (!tdb->read_only)) {

    ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK,

            TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);

    locked = (ret == 0);

    if (locked) {

      ret = tdb_brlock(tdb, F_WRLCK, FREELIST_TOP, 0,

           TDB_LOCK_WAIT);

      if (ret == -1) {

        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "

           "tdb_brlock failed for %s: %s\n",

           name, strerror(errno)));

        goto fail;

      }

      ret = tdb_new_database(tdb, &header, hash_size);

      if (ret == -1) {

        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "

           "tdb_new_database failed for "

           "%s: %s\n", name, strerror(errno)));

        tdb_unlockall(tdb);

        goto fail;

      }

      ret = tdb_brunlock(tdb, F_WRLCK, FREELIST_TOP, 0);

      if (ret == -1) {

        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "

           "tdb_unlockall failed for %s: %s\n",

           name, strerror(errno)));

        goto fail;

      }

      ret = lseek(tdb->fd, 0, SEEK_SET);

      if (ret == -1) {

        TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "

           "lseek failed for %s: %s\n",

           name, strerror(errno)));

        goto fail;

      }

    }

  }

  errno = 0;

  if (read(tdb->fd, &header, sizeof(header)) != sizeof(header)

      /*

       * Call strncmp() rather than strcmp() in case header.magic_food is

       * not zero‐terminated. We’re still checking the full string for

       * equality, as tdb_header::magic_food is larger than

       * TDB_MAGIC_FOOD.

       */

      || strncmp(header.magic_food, TDB_MAGIC_FOOD, sizeof(header.magic_food)) != 0) {

    if (!(open_flags & O_CREAT) ||

        tdb_new_database(tdb, &header, hash_size) == -1) {

      if (errno == 0) {

        errno = EIO; /* ie bad format or something */

      }

      goto fail;

    }

    rev = (tdb->flags & TDB_CONVERT);

  } else if (header.version != TDB_VERSION

       && !(rev = (header.version==TDB_BYTEREV(TDB_VERSION)))) {

    /* wrong version */

    errno = EIO;

    goto fail;

  }

  vp = (unsigned char *)&header.version;

  vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) |

      (((uint32_t)vp[2]) << 8) | (uint32_t)vp[3];

  tdb->flags |= (vertest==TDB_VERSION) ? TDB_BIGENDIAN : 0;

  if (!rev)

    tdb->flags &= ~TDB_CONVERT;

  else {

    tdb->flags |= TDB_CONVERT;

    tdb_convert(&header, sizeof(header));

  }

  /*

   * We only use st.st_dev and st.st_ino from the raw fstat()

   * call, everything else needs to use tdb_fstat() in order

   * to skip tdb->hdr_ofs!

   */

  if (fstat(tdb->fd, &st) == -1) {

    goto fail;

  }

  tdb->device = st.st_dev;

  tdb->inode = st.st_ino;

  ZERO_STRUCT(st);

  if (header.rwlocks != 0 &&

      header.rwlocks != TDB_FEATURE_FLAG_MAGIC &&

      header.rwlocks != TDB_HASH_RWLOCK_MAGIC) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: spinlocks no longer supported\n"));

    errno = ENOSYS;

    goto fail;

  }

  if (header.hash_size == 0) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: invalid database: 0 hash_size\n"));

    errno = ENOSYS;

    goto fail;

  }

  tdb->hash_size = header.hash_size;

  if (header.rwlocks == TDB_FEATURE_FLAG_MAGIC) {

    tdb->feature_flags = header.feature_flags;

  }

  if (tdb->feature_flags & ~TDB_SUPPORTED_FEATURE_FLAGS) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: unsupported "

       "features in tdb %s: 0x%08x (supported: 0x%08x)\n",

       name, (unsigned)tdb->feature_flags,

       (unsigned)TDB_SUPPORTED_FEATURE_FLAGS));

    errno = ENOSYS;

    goto fail;

  }

  if (tdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {

    if (!tdb_mutex_open_ok(tdb, &header)) {

      errno = EINVAL;

      goto fail;

    }

    /*

     * We need to remember the hdr_ofs

     * also for the TDB_NOLOCK case

     * if the current library doesn't support

     * mutex locking.

     */

    tdb->hdr_ofs = header.mutex_size;

    if ((!(tdb_flags & TDB_CLEAR_IF_FIRST)) && (!tdb->read_only)) {

      /*

       * Open an existing mutexed tdb, but without

       * CLEAR_IF_FIRST. We need to initialize the

       * mutex array and keep the CLEAR_IF_FIRST

       * lock locked.

       */

      ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_WRLCK,

              TDB_LOCK_NOWAIT|TDB_LOCK_PROBE);

      locked = (ret == 0);

      if (locked) {

        ret = tdb_mutex_init(tdb);

        if (ret == -1) {

          TDB_LOG((tdb,

             TDB_DEBUG_FATAL,

             "tdb_open_ex: tdb_mutex_init "

             "failed for ""%s: %s\n",

             name, strerror(errno)));

          goto fail;

        }

      }

    }

  }

  if ((header.magic1_hash == 0) && (header.magic2_hash == 0)) {

    /* older TDB without magic hash references */

    tdb->hash_fn = tdb_old_hash;

  } else if (!check_header_hash(tdb, &header, !hash_fn,

              &magic1, &magic2)) {

    TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "

       "%s was not created with %s hash function we are using\n"

       "magic1_hash[0x%08X %s 0x%08X] "

       "magic2_hash[0x%08X %s 0x%08X]\n",

       name, hash_alg,

       header.magic1_hash,

       (header.magic1_hash == magic1) ? "==" : "!=",

       magic1,

       header.magic2_hash,

       (header.magic2_hash == magic2) ? "==" : "!=",

       magic2));

    errno = EINVAL;

    goto fail;

  }

  /* Is it already in the open list?  If so, fail. */

  if (tdb_already_open(tdb->device, tdb->inode)) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "

       "%s (%d,%d) is already open in this process\n",

       name, (int)tdb->device, (int)tdb->inode));

    errno = EBUSY;

    goto fail;

  }

  /*

   * We had tdb_mmap(tdb) here before,

   * but we need to use tdb_fstat(),

   * which is triggered from tdb_oob() before calling tdb_mmap().

   * As this skips tdb->hdr_ofs.

   */

  tdb->map_size = 0;

  ret = tdb_oob(tdb, 0, 1, 0);

  if (ret == -1) {

    errno = EIO;

    goto fail;

  }

  if (tdb->feature_flags & TDB_FEATURE_FLAG_MUTEX) {

    if (!(tdb->flags & TDB_NOLOCK)) {

      ret = tdb_mutex_mmap(tdb);

      if (ret != 0) {

        goto fail;

      }

    }

  }

  if (tdb->hash_size > UINT32_MAX/4) {

    TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "

       "hash size %"PRIu32" too large\n", tdb->hash_size));

    errno = EINVAL;

    goto fail;

  }

  ret = tdb_oob(tdb, FREELIST_TOP, 4*tdb->hash_size, 1);

  if (ret == -1) {

    TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_open_ex: "

       "hash size %"PRIu32" does not fit\n", tdb->hash_size));

    errno = EINVAL;

    goto fail;

  }

  if (locked) {

    if (tdb_nest_unlock(tdb, ACTIVE_LOCK, F_WRLCK, false) == -1) {

      TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: "

         "failed to release ACTIVE_LOCK on %s: %s\n",

         name, strerror(errno)));

      goto fail;

    }

  }

  if (locked || (tdb_flags & TDB_CLEAR_IF_FIRST)) {

    /*

     * We always need to do this if the CLEAR_IF_FIRST

     * flag is set, even if we didn't get the initial

     * exclusive lock as we need to let all other users

     * know we're using it.

     */

    ret = tdb_nest_lock(tdb, ACTIVE_LOCK, F_RDLCK, TDB_LOCK_WAIT);

    if (ret == -1) {

      goto fail;

    }

  }

  /* if needed, run recovery */

  if (tdb_transaction_recover(tdb) == -1) {

    goto fail;

  }

 internal:

  /* Internal (memory-only) databases skip all the code above to

   * do with disk files, and resume here by releasing their

   * open lock and hooking into the active list. */

#ifdef TDB_TRACE

  {

    char tracefile[64];

    if (tdb->flags & TDB_INTERNAL) {

      snprintf(tracefile, sizeof(tracefile),

         "tdb_%p.trace.%li", tdb, (long)getpid());

    } else {

      snprintf(tracefile, sizeof(tracefile),

         "%s.trace.%li", name, (long)getpid());

    }

    tdb->tracefd = open(tracefile, O_WRONLY|O_CREAT|O_EXCL, 0600);

    if (tdb->tracefd >= 0) {

      tdb_enable_seqnum(tdb);

      tdb_trace_open(tdb, "tdb_open", hash_size, tdb_flags,

               open_flags);

    } else

      TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to open trace file %s!\n", tracefile));

  }

#endif

  if (tdb_nest_unlock(tdb, OPEN_LOCK, F_WRLCK, false) == -1) {

    goto fail;

  }

  tdb->next = tdbs;

  tdbs = tdb;

  errno = orig_errno;

  return tdb;

 fail:

  { int save_errno = errno;

  if (!tdb)

    return NULL;

#ifdef TDB_TRACE

  close(tdb->tracefd);

#endif

  if (tdb->map_ptr) {

    if (tdb->flags & TDB_INTERNAL)

      SAFE_FREE(tdb->map_ptr);

    else

      tdb_munmap(tdb);

  }

  if (tdb->fd != -1)

    if (close(tdb->fd) != 0)

      TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_open_ex: failed to close tdb->fd on error!\n"));

  SAFE_FREE(tdb->lockrecs);

  SAFE_FREE(tdb->name);

  SAFE_FREE(tdb);

  errno = save_errno;

  return NULL;

  }

}

/*

 * Set the maximum number of dead records per hash chain

 */

_PUBLIC_ void tdb_set_max_dead(struct tdb_context *tdb, int max_dead)

{

  tdb->max_dead_records = max_dead;

}

/**

 * Close a database.

 *

 * @returns -1 for error; 0 for success.

 **/

_PUBLIC_ int tdb_close(struct tdb_context *tdb)

{

  struct tdb_context **i;

  int ret = 0;

  if (tdb->transaction) {

    tdb_transaction_cancel(tdb);

  }

  tdb_trace(tdb, "tdb_close");

  if (tdb->map_ptr) {

    if (tdb->flags & TDB_INTERNAL)

      SAFE_FREE(tdb->map_ptr);

    else

      tdb_munmap(tdb);

  }

  tdb_mutex_munmap(tdb);

  SAFE_FREE(tdb->name);

  if (tdb->fd != -1) {

    ret = close(tdb->fd);

    tdb->fd = -1;

  }

  SAFE_FREE(tdb->lockrecs);

  /* Remove from contexts list */

  for (i = &tdbs; *i; i = &(*i)->next) {

    if (*i == tdb) {

      *i = tdb->next;

      break;

    }

  }

#ifdef TDB_TRACE

  close(tdb->tracefd);

#endif

  memset(tdb, 0, sizeof(*tdb));

  SAFE_FREE(tdb);

  return ret;

}

/* register a logging function */

_PUBLIC_ void tdb_set_logging_function(struct tdb_context *tdb,

                                       const struct tdb_logging_context *log_ctx)

{

        tdb->log = *log_ctx;

}

_PUBLIC_ void *tdb_get_logging_private(struct tdb_context *tdb)

{

  return tdb->log.log_private;

}

static int tdb_reopen_internal(struct tdb_context *tdb, bool active_lock)

{

#if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \

  !defined(LIBREPLACE_PWRITE_NOT_REPLACED)

  struct stat st;

#endif

  if (tdb->flags & TDB_INTERNAL) {

    return 0; /* Nothing to do. */

  }

  if (tdb_have_extra_locks(tdb)) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed with locks held\n"));

    goto fail;

  }

  if (tdb->transaction != 0) {

    TDB_LOG((tdb, TDB_DEBUG_ERROR, "tdb_reopen: reopen not allowed inside a transaction\n"));

    goto fail;

  }

/* If we have real pread & pwrite, we can skip reopen. */

#if !defined(LIBREPLACE_PREAD_NOT_REPLACED) || \

  !defined(LIBREPLACE_PWRITE_NOT_REPLACED)

  if (tdb_munmap(tdb) != 0) {

    TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_reopen: munmap failed (%s)\n", strerror(errno)));

    goto fail;