/*-
 * 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  8.12 (Berkeley) 11/18/94";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#ifdef RECNO_USE_MMAP
#include <sys/mman.h>
#endif
#include <sys/stat.h>

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

#include "db-int.h"
#include "recno.h"

DB *
__rec_open(const char *fname, int flags, int mode, const RECNOINFO *openinfo,
           int dflags)
{
        BTREE *t;
        BTREEINFO btopeninfo;
        DB *dbp;
        PAGE *h;
        struct stat sb;
        int rfd = -1, sverrno;

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

        if (fname != NULL && fcntl(rfd, F_SETFD, 1) == -1) {
                close(rfd);
                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 | O_BINARY, S_IRUSR | S_IWUSR, &btopeninfo, dflags);
        } else
                dbp = __bt_open(NULL, O_RDWR | O_BINARY, 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, "rb")) == 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 RECNO_USE_MMAP
                                /*
                                 * 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)) == (caddr_t)-1)
                                        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(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);
}