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);
}