text: /*      $OpenBSD: bt_close.c,v 1.11 2021/10/24 10:05:22 jsg Exp $       */
  
  /*-
   * Copyright (c) 1990, 1993, 1994
   *      The Regents of the University of California.  All rights reserved.
   * Copyright (c) 2022 Jeffrey H. Johnson <trnsz@pobox.com>
   *
   * This code is derived from software contributed to Berkeley by
   * Mike Olson.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include "../../include/compat.h"
  
  #include <errno.h>
  #include <stdio.h>
  #include <bsd_stdlib.h>
  #include <bsd_string.h>
  #include <bsd_unistd.h>
  
  #include <bsd_db.h>
  #include <compat_bsd_db.h>
  #include "btree.h"
  
  static int bt_meta(BTREE *);
  
  /*
   * BT_CLOSE -- Close a btree.
   *
   * Parameters:
   *      dbp:    pointer to access method
   *
   * Returns:
   *      RET_ERROR, RET_SUCCESS
   */
  int
  __bt_close(DB *dbp)
  {
          BTREE *t;
          int fd;
  
          t = dbp->internal;
  
          /* Toss any page pinned across calls. */
          if (t->bt_pinned != NULL) {
                  mpool_put(t->bt_mp, t->bt_pinned, 0);
                  t->bt_pinned = NULL;
          }
  
          /* Sync the tree. */
          if (__bt_sync(dbp, 0) == RET_ERROR)
                  return (RET_ERROR);
  
          /* Close the memory pool. */
          if (mpool_close(t->bt_mp) == RET_ERROR)
                  return (RET_ERROR);
  
          /* Free random memory. */
          if (t->bt_cursor.key.data != NULL) {
                  free(t->bt_cursor.key.data);
                  t->bt_cursor.key.size = 0;
                  t->bt_cursor.key.data = NULL;
          }
          if (t->bt_rkey.data) {
                  free(t->bt_rkey.data);
                  t->bt_rkey.size = 0;
                  t->bt_rkey.data = NULL;
          }
          if (t->bt_rdata.data) {
                  free(t->bt_rdata.data);
                  t->bt_rdata.size = 0;
                  t->bt_rdata.data = NULL;
          }
  
          fd = t->bt_fd;
          free(t);
          free(dbp);
          return (close(fd) ? RET_ERROR : RET_SUCCESS);
  }
  
  /*
   * BT_SYNC -- sync the btree to disk.
   *
   * Parameters:
   *      dbp:    pointer to access method
   *
   * Returns:
   *      RET_SUCCESS, RET_ERROR.
   */
  int
  __bt_sync(const DB *dbp, u_int flags)
  {
          BTREE *t;
          int status;
  
          t = dbp->internal;
  
          /* Toss any page pinned across calls. */
          if (t->bt_pinned != NULL) {
                  mpool_put(t->bt_mp, t->bt_pinned, 0);
                  t->bt_pinned = NULL;
          }
  
          /* Sync doesn't currently take any flags. */
          if (flags != 0) {
                  errno = EINVAL;
                  return (RET_ERROR);
          }
  
          if (F_ISSET(t, B_INMEM | B_RDONLY) || !F_ISSET(t, B_MODIFIED))
                  return (RET_SUCCESS);
  
          if (F_ISSET(t, B_METADIRTY) && bt_meta(t) == RET_ERROR)
                  return (RET_ERROR);
  
          if ((status = mpool_sync(t->bt_mp)) == RET_SUCCESS)
                  F_CLR(t, B_MODIFIED);
  
          return (status);
  }
  
  /*
   * BT_META -- write the tree meta data to disk.
   *
   * Parameters:
   *      t:      tree
   *
   * Returns:
   *      RET_ERROR, RET_SUCCESS
   */
  static int
  bt_meta(BTREE *t)
  {
          BTMETA m;
          void *p;
  
          if ((p = mpool_get(t->bt_mp, P_META, 0)) == NULL)
                  return (RET_ERROR);
  
          /* Fill in metadata. */
          m.magic = BTREEMAGIC;
          m.version = BTREEVERSION;
          m.psize = t->bt_psize;
          m.free = t->bt_free;
          m.nrecs = t->bt_nrecs;
          m.flags = F_ISSET(t, SAVEMETA);
  
          memmove(p, &m, sizeof(BTMETA));
          mpool_put(t->bt_mp, p, MPOOL_DIRTY);
          return (RET_SUCCESS);
  }
  