os_open.c

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/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1997, 1998, 1999, 2000
 *      Sleepycat Software.  All rights reserved.
 */

#include "config.h"

#ifndef lint
static const char revid[] = "$Id: os__open_8c-source.html,v 1.1 2008/06/08 10:21:26 sebdiaz Exp $";
#endif /* not lint */

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>

#include <fcntl.h>
#include <string.h>
#endif

#include "db_int.h"

/*
 * CDB___os_open --
 *      Open a file.
 *
 * PUBLIC: int CDB___os_open __P((DB_ENV *, const char *, u_int32_t, int, DB_FH *));
 */
int
CDB___os_open(dbenv, name, flags, mode, fhp)
        DB_ENV *dbenv;
        const char *name;
        u_int32_t flags;
        int mode;
        DB_FH *fhp;
{
        int oflags, ret;

        oflags = 0;

        /*
         * DB requires the POSIX 1003.1 semantic that two files opened at the
         * same time with DB_OSO_CREATE/O_CREAT and DB_OSO_EXCL/O_EXCL flags
         * set return an EEXIST failure in at least one.
         */
        if (LF_ISSET(DB_OSO_CREATE))
                oflags |= O_CREAT;

        if (LF_ISSET(DB_OSO_EXCL))
                oflags |= O_EXCL;

#if defined(O_DSYNC) && defined(XXX_NEVER_SET)
        /*
         * !!!
         * We should get better performance if we push the log files to disk
         * immediately instead of waiting for the sync.  However, Solaris
         * (and likely any other system based on the 4BSD filesystem releases),
         * doesn't implement O_DSYNC correctly, only flushing data blocks and
         * not inode or indirect blocks.
         */
        if (LF_ISSET(DB_OSO_LOG))
                oflags |= O_DSYNC;
#endif

        if (LF_ISSET(DB_OSO_RDONLY))
                oflags |= O_RDONLY;
        else
                oflags |= O_RDWR;

        if (LF_ISSET(DB_OSO_TRUNC))
                oflags |= O_TRUNC;

        /* Open the file. */
        if ((ret = CDB___os_openhandle(dbenv, name, oflags, mode, fhp)) != 0)
                return (ret);

        /*
         * Delete any temporary file.
         *
         * !!!
         * There's a race here, where we've created a file and we crash before
         * we can unlink it.  Temporary files aren't common in DB, regardless,
         * it's not a security problem because the file is empty.  There's no
         * reasonable way to avoid the race (playing signal games isn't worth
         * the portability nightmare), so we just live with it.
         */
        if (LF_ISSET(DB_OSO_TEMP))
                (void)CDB___os_unlink(dbenv, name);

        return (0);
}

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