xref: /csrg-svn/lib/libc/db/recno/rec_open.c (revision 66228)

/*-
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Mike Olson.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)rec_open.c	8.6 (Berkeley) 02/22/94";
#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 <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, 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) {
			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';

	SET(t, R_RECNO);
	if (fname == NULL)
		SET(t, R_EOF | R_INMEM);
	else
		t->bt_rfd = rfd;
	t->bt_rcursor = 0;

	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:
				SET(t, R_RDONLY);
				break;
			default:
				goto einval;
			}
slow:			if ((t->bt_rfp = fdopen(rfd, "r")) == NULL)
				goto err;
			SET(t, R_CLOSEFP);
			t->bt_irec =
			    ISSET(t, R_FIXLEN) ? __rec_fpipe : __rec_vpipe;
		} else {
			switch (flags & O_ACCMODE) {
			case O_RDONLY:
				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)
				SET(t, R_EOF);
			else {
				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 = ISSET(t, R_FIXLEN) ?
				    __rec_fmap : __rec_vmap;
				SET(t, R_MEMMAPPED);
			}
		}
	}

	/* 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) {
		h->flags = h->flags & ~P_TYPE | P_RLEAF;
		mpool_put(t->bt_mp, h, MPOOL_DIRTY);
	} else
		mpool_put(t->bt_mp, h, 0);

	if (openinfo && openinfo->flags & R_SNAPSHOT &&
	    !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 (ISSET(t, R_INMEM)) {
		errno = ENOENT;
		return (-1);
	}
	return (t->bt_rfd);
}