rec_open.c

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/*-
 * Copyright (c) 1990, 1993, 1994
 * The Regents of the University of California.  All rights reserved.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 * This product includes software developed by the University of
 * California, Berkeley and its contributors.
 * 4. 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)rec_open.c 8.10 (Berkeley) 9/1/94";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <unistd.h>

#include "../include/db.h"
#include "recno.h"

DB *
__rec_open(fname, flags, mode, openinfo, dflags)
   const char *fname;
   int flags, mode, dflags;
   const RECNOINFO *openinfo;
{
   BTREE *t;
   BTREEINFO btopeninfo;
   DB *dbp;
   PAGE *h;
   struct stat sb;
   int rfd = 0, sverrno;

   /* Open the user's file -- if this fails, we're done. */
   if (fname != NULL && (rfd = open(fname, flags, mode)) < 0)
      return (NULL);

   /* Create a btree in memory (backed by disk). */
   dbp = NULL;
   if (openinfo) {
      if (openinfo->flags & ~(R_FIXEDLEN | R_NOKEY | R_SNAPSHOT))
         goto einval;
      btopeninfo.flags = 0;
      btopeninfo.cachesize = openinfo->cachesize;
      btopeninfo.maxkeypage = 0;
      btopeninfo.minkeypage = 0;
      btopeninfo.psize = openinfo->psize;
      btopeninfo.compare = NULL;
      btopeninfo.prefix = NULL;
      btopeninfo.lorder = openinfo->lorder;
      dbp = __bt_open(openinfo->bfname,
          O_RDWR, S_IRUSR | S_IWUSR, &btopeninfo, dflags);
   } else
      dbp = __bt_open(NULL, O_RDWR, S_IRUSR | S_IWUSR, NULL, dflags);
   if (dbp == NULL)
      goto err;

   /*
    * Some fields in the tree structure are recno specific.  Fill them
    * in and make the btree structure look like a recno structure.  We
    * don't change the bt_ovflsize value, it's close enough and slightly
    * bigger.
    */
   t = dbp->internal;
   if (openinfo) {
      if (openinfo->flags & R_FIXEDLEN) {
         F_SET(t, R_FIXLEN);
         t->bt_reclen = openinfo->reclen;
         if (t->bt_reclen == 0)
            goto einval;
      }
      t->bt_bval = openinfo->bval;
   } else
      t->bt_bval = '\n';

   F_SET(t, R_RECNO);
   if (fname == NULL)
      F_SET(t, R_EOF | R_INMEM);
   else
      t->bt_rfd = rfd;

   if (fname != NULL) {
      /*
       * In 4.4BSD, stat(2) returns true for ISSOCK on pipes.
       * Unfortunately, that's not portable, so we use lseek
       * and check the errno values.
       */
      errno = 0;
      if (lseek(rfd, (off_t)0, SEEK_CUR) == -1 && errno == ESPIPE) {
         switch (flags & O_ACCMODE) {
         case O_RDONLY:
            F_SET(t, R_RDONLY);
            break;
         default:
            goto einval;
         }
slow:       if ((t->bt_rfp = fdopen(rfd, "r")) == NULL)
            goto err;
         F_SET(t, R_CLOSEFP);
         t->bt_irec =
             F_ISSET(t, R_FIXLEN) ? __rec_fpipe : __rec_vpipe;
      } else {
         switch (flags & O_ACCMODE) {
         case O_RDONLY:
            F_SET(t, R_RDONLY);
            break;
         case O_RDWR:
            break;
         default:
            goto einval;
         }

         if (fstat(rfd, &sb))
            goto err;
         /*
          * Kluge -- we'd like to test to see if the file is too
          * big to mmap.  Since, we don't know what size or type
          * off_t's or size_t's are, what the largest unsigned
          * integral type is, or what random insanity the local
          * C compiler will perpetrate, doing the comparison in
          * a portable way is flatly impossible.  Hope that mmap
          * fails if the file is too large.
          */
         if (sb.st_size == 0)
            F_SET(t, R_EOF);
         else {
#ifdef MMAP_NOT_AVAILABLE
            /*
             * XXX
             * Mmap doesn't work correctly on many current
             * systems.  In particular, it can fail subtly,
             * with cache coherency problems.  Don't use it
             * for now.
             */
            t->bt_msize = sb.st_size;
            if ((t->bt_smap = mmap(NULL, t->bt_msize,
                PROT_READ, MAP_PRIVATE, rfd,
                (off_t)0)) == MAP_FAILED
               goto slow;
            t->bt_cmap = t->bt_smap;
            t->bt_emap = t->bt_smap + sb.st_size;
            t->bt_irec = F_ISSET(t, R_FIXLEN) ?
                __rec_fmap : __rec_vmap;
            F_SET(t, R_MEMMAPPED);
#else
            goto slow;
#endif
         }
      }
   }

   /* Use the recno routines. */
   dbp->close = __rec_close;
   dbp->del = __rec_delete;
   dbp->fd = __rec_fd;
   dbp->get = __rec_get;
   dbp->put = __rec_put;
   dbp->seq = __rec_seq;
   dbp->sync = __rec_sync;

   /* If the root page was created, reset the flags. */
   if ((h = mpool_get(t->bt_mp, P_ROOT, 0)) == NULL)
      goto err;
   if ((h->flags & P_TYPE) == P_BLEAF) {
      F_CLR(h, P_TYPE);
      F_SET(h, P_RLEAF);
      mpool_put(t->bt_mp, h, MPOOL_DIRTY);
   } else
      mpool_put(t->bt_mp, h, 0);

   if (openinfo && openinfo->flags & R_SNAPSHOT &&
       !F_ISSET(t, R_EOF | R_INMEM) &&
       t->bt_irec(t, MAX_REC_NUMBER) == RET_ERROR)
                goto err;
   return (dbp);

einval:  errno = EINVAL;
err:  sverrno = errno;
   if (dbp != NULL)
      (void)__bt_close(dbp);
   if (fname != NULL)
      (void)close(rfd);
   errno = sverrno;
   return (NULL);
}

int
__rec_fd(dbp)
   const DB *dbp;
{
   BTREE *t;

   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;
   }

   /* In-memory database can't have a file descriptor. */
   if (F_ISSET(t, R_INMEM)) {
      errno = ENOENT;
      return (-1);
   }
   return (t->bt_rfd);
}