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);
}