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db_iface.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998, 1999, 2000
 *    Sleepycat Software.  All rights reserved.
 */

#include "db_config.h"

#ifndef lint
static const char revid[] = "$Id: db_iface.c,v 11.34 2001/01/11 18:19:51 bostic Exp $";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <errno.h>
#endif

#include "db_int.h"
#include "db_page.h"
#include "db_am.h"
#include "btree.h"

static int __db_curinval __P((const DB_ENV *));
static int __db_rdonly __P((const DB_ENV *, const char *));
static int __dbt_ferr __P((const DB *, const char *, const DBT *, int));

/*
 * __db_cursorchk --
 *    Common cursor argument checking routine.
 *
 * PUBLIC: int __db_cursorchk __P((const DB *, u_int32_t, int));
 */
int
__db_cursorchk(dbp, flags, isrdonly)
      const DB *dbp;
      u_int32_t flags;
      int isrdonly;
{
      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
            break;
      case DB_WRITECURSOR:
            if (isrdonly)
                  return (__db_rdonly(dbp->dbenv, "DB->cursor"));
            if (!CDB_LOCKING(dbp->dbenv))
                  return (__db_ferr(dbp->dbenv, "DB->cursor", 0));
            break;
      case DB_WRITELOCK:
            if (isrdonly)
                  return (__db_rdonly(dbp->dbenv, "DB->cursor"));
            break;
      default:
            return (__db_ferr(dbp->dbenv, "DB->cursor", 0));
      }

      return (0);
}

/*
 * __db_ccountchk --
 *    Common cursor count argument checking routine.
 *
 * PUBLIC: int __db_ccountchk __P((const DB *, u_int32_t, int));
 */
int
__db_ccountchk(dbp, flags, isvalid)
      const DB *dbp;
      u_int32_t flags;
      int isvalid;
{
      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
            break;
      default:
            return (__db_ferr(dbp->dbenv, "DBcursor->c_count", 0));
      }

      /*
       * The cursor must be initialized, return EINVAL for an invalid cursor,
       * otherwise 0.
       */
      return (isvalid ? 0 : __db_curinval(dbp->dbenv));
}

/*
 * __db_cdelchk --
 *    Common cursor delete argument checking routine.
 *
 * PUBLIC: int __db_cdelchk __P((const DB *, u_int32_t, int, int));
 */
int
__db_cdelchk(dbp, flags, isrdonly, isvalid)
      const DB *dbp;
      u_int32_t flags;
      int isrdonly, isvalid;
{
      /* Check for changes to a read-only tree. */
      if (isrdonly)
            return (__db_rdonly(dbp->dbenv, "c_del"));

      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
            break;
      default:
            return (__db_ferr(dbp->dbenv, "DBcursor->c_del", 0));
      }

      /*
       * The cursor must be initialized, return EINVAL for an invalid cursor,
       * otherwise 0.
       */
      return (isvalid ? 0 : __db_curinval(dbp->dbenv));
}

/*
 * __db_cgetchk --
 *    Common cursor get argument checking routine.
 *
 * PUBLIC: int __db_cgetchk __P((const DB *, DBT *, DBT *, u_int32_t, int));
 */
int
__db_cgetchk(dbp, key, data, flags, isvalid)
      const DB *dbp;
      DBT *key, *data;
      u_int32_t flags;
      int isvalid;
{
      int ret;

      /*
       * Check for read-modify-write validity.  DB_RMW doesn't make sense
       * with CDB cursors since if you're going to write the cursor, you
       * had to create it with DB_WRITECURSOR.  Regardless, we check for
       * LOCKING_ON and not STD_LOCKING, as we don't want to disallow it.
       * If this changes, confirm that DB does not itself set the DB_RMW
       * flag in a path where CDB may have been configured.
       */
      if (LF_ISSET(DB_RMW)) {
            if (!LOCKING_ON(dbp->dbenv)) {
                  __db_err(dbp->dbenv,
                      "the DB_RMW flag requires locking");
                  return (EINVAL);
            }
            LF_CLR(DB_RMW);
      }

      /* Check for invalid function flags. */
      switch (flags) {
      case DB_CONSUME:
      case DB_CONSUME_WAIT:
            if (dbp->type != DB_QUEUE)
                  goto err;
            break;
      case DB_CURRENT:
      case DB_FIRST:
      case DB_GET_BOTH:
      case DB_LAST:
      case DB_NEXT:
      case DB_NEXT_DUP:
      case DB_NEXT_NODUP:
      case DB_PREV:
      case DB_PREV_NODUP:
      case DB_SET:
      case DB_SET_RANGE:
            break;
      case DB_GET_BOTHC:
            if (dbp->type == DB_QUEUE)
                  goto err;
            break;
      case DB_GET_RECNO:
            if (!F_ISSET(dbp, DB_BT_RECNUM))
                  goto err;
            break;
      case DB_SET_RECNO:
            if (!F_ISSET(dbp, DB_BT_RECNUM))
                  goto err;
            break;
      default:
err:        return (__db_ferr(dbp->dbenv, "DBcursor->c_get", 0));
      }

      /* Check for invalid key/data flags. */
      if ((ret = __dbt_ferr(dbp, "key", key, 0)) != 0)
            return (ret);
      if ((ret = __dbt_ferr(dbp, "data", data, 0)) != 0)
            return (ret);

      /*
       * The cursor must be initialized for DB_CURRENT or DB_NEXT_DUP,
       * return EINVAL for an invalid cursor, otherwise 0.
       */
      if (isvalid || (flags != DB_CURRENT && flags != DB_NEXT_DUP))
            return (0);

      return (__db_curinval(dbp->dbenv));
}

/*
 * __db_cputchk --
 *    Common cursor put argument checking routine.
 *
 * PUBLIC: int __db_cputchk __P((const DB *,
 * PUBLIC:    const DBT *, DBT *, u_int32_t, int, int));
 */
int
__db_cputchk(dbp, key, data, flags, isrdonly, isvalid)
      const DB *dbp;
      const DBT *key;
      DBT *data;
      u_int32_t flags;
      int isrdonly, isvalid;
{
      int key_flags, ret;

      key_flags = 0;

      /* Check for changes to a read-only tree. */
      if (isrdonly)
            return (__db_rdonly(dbp->dbenv, "c_put"));

      /* Check for invalid function flags. */
      switch (flags) {
      case DB_AFTER:
      case DB_BEFORE:
            switch (dbp->type) {
            case DB_BTREE:
            case DB_HASH:           /* Only with unsorted duplicates. */
                  if (!F_ISSET(dbp, DB_AM_DUP))
                        goto err;
                  if (dbp->dup_compare != NULL)
                        goto err;
                  break;
            case DB_QUEUE:          /* Not permitted. */
                  goto err;
            case DB_RECNO:          /* Only with mutable record numbers. */
                  if (!F_ISSET(dbp, DB_RE_RENUMBER))
                        goto err;
                  key_flags = 1;
                  break;
            default:
                  goto err;
            }
            break;
      case DB_CURRENT:
            /*
             * If there is a comparison function, doing a DB_CURRENT
             * must not change the part of the data item that is used
             * for the comparison.
             */
            break;
      case DB_NODUPDATA:
            if (!F_ISSET(dbp, DB_AM_DUPSORT))
                  goto err;
            /* FALLTHROUGH */
      case DB_KEYFIRST:
      case DB_KEYLAST:
            if (dbp->type == DB_QUEUE || dbp->type == DB_RECNO)
                  goto err;
            key_flags = 1;
            break;
      default:
err:        return (__db_ferr(dbp->dbenv, "DBcursor->c_put", 0));
      }

      /* Check for invalid key/data flags. */
      if (key_flags && (ret = __dbt_ferr(dbp, "key", key, 0)) != 0)
            return (ret);
      if ((ret = __dbt_ferr(dbp, "data", data, 0)) != 0)
            return (ret);

      /*
       * The cursor must be initialized for anything other than DB_KEYFIRST
       * and DB_KEYLAST, return EINVAL for an invalid cursor, otherwise 0.
       */
      if (isvalid || flags == DB_KEYFIRST ||
          flags == DB_KEYLAST || flags == DB_NODUPDATA)
            return (0);

      return (__db_curinval(dbp->dbenv));
}

/*
 * __db_closechk --
 *    DB->close flag check.
 *
 * PUBLIC: int __db_closechk __P((const DB *, u_int32_t));
 */
int
__db_closechk(dbp, flags)
      const DB *dbp;
      u_int32_t flags;
{
      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
      case DB_NOSYNC:
            break;
      default:
            return (__db_ferr(dbp->dbenv, "DB->close", 0));
      }

      return (0);
}

/*
 * __db_delchk --
 *    Common delete argument checking routine.
 *
 * PUBLIC: int __db_delchk __P((const DB *, DBT *, u_int32_t, int));
 */
int
__db_delchk(dbp, key, flags, isrdonly)
      const DB *dbp;
      DBT *key;
      u_int32_t flags;
      int isrdonly;
{
      COMPQUIET(key, NULL);

      /* Check for changes to a read-only tree. */
      if (isrdonly)
            return (__db_rdonly(dbp->dbenv, "delete"));

      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
            break;
      default:
            return (__db_ferr(dbp->dbenv, "DB->del", 0));
      }

      return (0);
}

/*
 * __db_getchk --
 *    Common get argument checking routine.
 *
 * PUBLIC: int __db_getchk __P((const DB *, const DBT *, DBT *, u_int32_t));
 */
int
__db_getchk(dbp, key, data, flags)
      const DB *dbp;
      const DBT *key;
      DBT *data;
      u_int32_t flags;
{
      int ret;

      /*
       * Check for read-modify-write validity.  DB_RMW doesn't make sense
       * with CDB cursors since if you're going to write the cursor, you
       * had to create it with DB_WRITECURSOR.  Regardless, we check for
       * LOCKING_ON and not STD_LOCKING, as we don't want to disallow it.
       * If this changes, confirm that DB does not itself set the DB_RMW
       * flag in a path where CDB may have been configured.
       */
      if (LF_ISSET(DB_RMW)) {
            if (!LOCKING_ON(dbp->dbenv)) {
                  __db_err(dbp->dbenv,
                      "the DB_RMW flag requires locking");
                  return (EINVAL);
            }
            LF_CLR(DB_RMW);
      }

      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
      case DB_GET_BOTH:
            break;
      case DB_SET_RECNO:
            if (!F_ISSET(dbp, DB_BT_RECNUM))
                  goto err;
            break;
      case DB_CONSUME:
      case DB_CONSUME_WAIT:
            if (dbp->type == DB_QUEUE)
                  break;
            /* Fall through */
      default:
err:        return (__db_ferr(dbp->dbenv, "DB->get", 0));
      }

      /* Check for invalid key/data flags. */
      if ((ret = __dbt_ferr(dbp, "key", key, flags == DB_SET_RECNO)) != 0)
            return (ret);
      if ((ret = __dbt_ferr(dbp, "data", data, 1)) != 0)
            return (ret);

      return (0);
}

/*
 * __db_joinchk --
 *    Common join argument checking routine.
 *
 * PUBLIC: int __db_joinchk __P((const DB *, DBC * const *, u_int32_t));
 */
int
__db_joinchk(dbp, curslist, flags)
      const DB *dbp;
      DBC * const *curslist;
      u_int32_t flags;
{
      DB_TXN *txn;
      int i;

      switch (flags) {
      case 0:
      case DB_JOIN_NOSORT:
            break;
      default:
            return (__db_ferr(dbp->dbenv, "DB->join", 0));
      }

      if (curslist == NULL || curslist[0] == NULL) {
            __db_err(dbp->dbenv,
          "At least one secondary cursor must be specified to DB->join");
            return (EINVAL);
      }

      txn = curslist[0]->txn;
      for (i = 1; curslist[i] != NULL; i++)
            if (curslist[i]->txn != txn) {
                  __db_err(dbp->dbenv,
                "All secondary cursors must share the same transaction");
                  return (EINVAL);
            }

      return (0);
}

/*
 * __db_joingetchk --
 *    Common join_get argument checking routine.
 *
 * PUBLIC: int __db_joingetchk __P((const DB *, DBT *, u_int32_t));
 */
int
__db_joingetchk(dbp, key, flags)
      const DB *dbp;
      DBT *key;
      u_int32_t flags;
{

      if (LF_ISSET(DB_RMW)) {
            if (!LOCKING_ON(dbp->dbenv)) {
                  __db_err(dbp->dbenv,
                      "the DB_RMW flag requires locking");
                  return (EINVAL);
            }
            LF_CLR(DB_RMW);
      }

      switch (flags) {
      case 0:
      case DB_JOIN_ITEM:
            break;
      default:
            return (__db_ferr(dbp->dbenv, "DBcursor->c_get", 0));
      }

      /*
       * A partial get of the key of a join cursor don't make much sense;
       * the entire key is necessary to query the primary database
       * and find the datum, and so regardless of the size of the key
       * it would not be a performance improvement.  Since it would require
       * special handling, we simply disallow it.
       *
       * A partial get of the data, however, potentially makes sense (if
       * all possible data are a predictable large structure, for instance)
       * and causes us no headaches, so we permit it.
       */
      if (F_ISSET(key, DB_DBT_PARTIAL)) {
            __db_err(dbp->dbenv,
                "DB_DBT_PARTIAL may not be set on key during join_get");
            return (EINVAL);
      }

      return (0);
}

/*
 * __db_putchk --
 *    Common put argument checking routine.
 *
 * PUBLIC: int __db_putchk
 * PUBLIC:    __P((const DB *, DBT *, const DBT *, u_int32_t, int, int));
 */
int
__db_putchk(dbp, key, data, flags, isrdonly, isdup)
      const DB *dbp;
      DBT *key;
      const DBT *data;
      u_int32_t flags;
      int isrdonly, isdup;
{
      int ret;

      /* Check for changes to a read-only tree. */
      if (isrdonly)
            return (__db_rdonly(dbp->dbenv, "put"));

      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
      case DB_NOOVERWRITE:
            break;
      case DB_APPEND:
            if (dbp->type != DB_RECNO && dbp->type != DB_QUEUE)
                  goto err;
            break;
      case DB_NODUPDATA:
            if (F_ISSET(dbp, DB_AM_DUPSORT))
                  break;
            /* FALLTHROUGH */
      default:
err:        return (__db_ferr(dbp->dbenv, "DB->put", 0));
      }

      /* Check for invalid key/data flags. */
      if ((ret = __dbt_ferr(dbp, "key", key, 0)) != 0)
            return (ret);
      if ((ret = __dbt_ferr(dbp, "data", data, 0)) != 0)
            return (ret);

      /* Check for partial puts in the presence of duplicates. */
      if (isdup && F_ISSET(data, DB_DBT_PARTIAL)) {
            __db_err(dbp->dbenv,
"a partial put in the presence of duplicates requires a cursor operation");
            return (EINVAL);
      }

      return (0);
}

/*
 * __db_removechk --
 *    DB->remove flag check.
 *
 * PUBLIC: int __db_removechk __P((const DB *, u_int32_t));
 */
int
__db_removechk(dbp, flags)
      const DB *dbp;
      u_int32_t flags;
{
      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
            break;
      default:
            return (__db_ferr(dbp->dbenv, "DB->remove", 0));
      }

      return (0);
}

/*
 * __db_statchk --
 *    Common stat argument checking routine.
 *
 * PUBLIC: int __db_statchk __P((const DB *, u_int32_t));
 */
int
__db_statchk(dbp, flags)
      const DB *dbp;
      u_int32_t flags;
{
      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
      case DB_CACHED_COUNTS:
            break;
      case DB_RECORDCOUNT:
            if (dbp->type == DB_RECNO)
                  break;
            if (dbp->type == DB_BTREE && F_ISSET(dbp, DB_BT_RECNUM))
                  break;
            goto err;
      default:
err:        return (__db_ferr(dbp->dbenv, "DB->stat", 0));
      }

      return (0);
}

/*
 * __db_syncchk --
 *    Common sync argument checking routine.
 *
 * PUBLIC: int __db_syncchk __P((const DB *, u_int32_t));
 */
int
__db_syncchk(dbp, flags)
      const DB *dbp;
      u_int32_t flags;
{
      /* Check for invalid function flags. */
      switch (flags) {
      case 0:
            break;
      default:
            return (__db_ferr(dbp->dbenv, "DB->sync", 0));
      }

      return (0);
}

/*
 * __dbt_ferr --
 *    Check a DBT for flag errors.
 */
static int
__dbt_ferr(dbp, name, dbt, check_thread)
      const DB *dbp;
      const char *name;
      const DBT *dbt;
      int check_thread;
{
      DB_ENV *dbenv;
      int ret;

      dbenv = dbp->dbenv;

      /*
       * Check for invalid DBT flags.  We allow any of the flags to be
       * specified to any DB or DBcursor call so that applications can
       * set DB_DBT_MALLOC when retrieving a data item from a secondary
       * database and then specify that same DBT as a key to a primary
       * database, without having to clear flags.
       */
      if ((ret = __db_fchk(dbenv, name, dbt->flags,
          DB_DBT_MALLOC | DB_DBT_DUPOK |
          DB_DBT_REALLOC | DB_DBT_USERMEM | DB_DBT_PARTIAL)) != 0)
            return (ret);
      switch (F_ISSET(dbt, DB_DBT_MALLOC | DB_DBT_REALLOC | DB_DBT_USERMEM)) {
      case 0:
      case DB_DBT_MALLOC:
      case DB_DBT_REALLOC:
      case DB_DBT_USERMEM:
            break;
      default:
            return (__db_ferr(dbenv, name, 1));
      }

      if (check_thread && DB_IS_THREADED(dbp) &&
          !F_ISSET(dbt, DB_DBT_MALLOC | DB_DBT_REALLOC | DB_DBT_USERMEM)) {
            __db_err(dbenv,
                "DB_THREAD mandates memory allocation flag on DBT %s",
                name);
            return (EINVAL);
      }
      return (0);
}

/*
 * __db_rdonly --
 *    Common readonly message.
 */
static int
__db_rdonly(dbenv, name)
      const DB_ENV *dbenv;
      const char *name;
{
      __db_err(dbenv, "%s: attempt to modify a read-only tree", name);
      return (EACCES);
}

/*
 * __db_curinval
 *    Report that a cursor is in an invalid state.
 */
static int
__db_curinval(dbenv)
      const DB_ENV *dbenv;
{
      __db_err(dbenv,
          "Cursor position must be set before performing this operation");
      return (EINVAL);
}

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