os_handle.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1998-2005
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: os_handle.c,v 12.3 2005/11/02 03:12:18 mjc Exp $
 */

#include "db_config.h"

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

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

#include "db_int.h"

/*
 * __os_openhandle --
 *      Open a file, using POSIX 1003.1 open flags.
 */
int
__os_openhandle(dbenv, name, flags, mode, fhpp)
        DB_ENV *dbenv;
        const char *name;
        int flags, mode;
        DB_FH **fhpp;
{
        DB_FH *fhp;
        int ret, nrepeat, retries;

        if ((ret = __os_calloc(dbenv, 1, sizeof(DB_FH), fhpp)) != 0)
                return (ret);
        fhp = *fhpp;

        /* If the application specified an interface, use it. */
        if (DB_GLOBAL(j_open) != NULL) {
                if ((fhp->fd = DB_GLOBAL(j_open)(name, flags, mode)) == -1) {
                        ret = __os_get_errno();
                        goto err;
                }
                F_SET(fhp, DB_FH_OPENED);
                return (0);
        }

        retries = 0;
        for (nrepeat = 1; nrepeat < 4; ++nrepeat) {
                ret = 0;
                fhp->fd = _open(name, flags, mode);

                if (fhp->fd != -1) {
                        F_SET(fhp, DB_FH_OPENED);
                        break;
                }

                switch (ret = __os_get_errno()) {
                case EMFILE:
                case ENFILE:
                case ENOSPC:
                        /*
                         * If it's a "temporary" error, we retry up to 3 times,
                         * waiting up to 12 seconds.  While it's not a problem
                         * if we can't open a database, an inability to open a
                         * log file is cause for serious dismay.
                         */
                        __os_sleep(dbenv, nrepeat * 2, 0);
                        break;
                case EAGAIN:
                case EBUSY:
                case EINTR:
                        /*
                         * If an EAGAIN, EBUSY or EINTR, retry immediately for
                         * DB_RETRY times.
                         */
                        if (++retries < DB_RETRY)
                                --nrepeat;
                        break;
                }
        }

err:    if (ret != 0) {
                (void)__os_closehandle(dbenv, fhp);
                *fhpp = NULL;
        }

        return (ret);
}

/*
 * __os_closehandle --
 *      Close a file.
 */
int
__os_closehandle(dbenv, fhp)
        DB_ENV *dbenv;
        DB_FH *fhp;
{
        int ret;

        ret = 0;

        /*
         * If we have a valid handle, close it and unlink any temporary
         * file.
         */
        if (F_ISSET(fhp, DB_FH_OPENED)) {
                if (DB_GLOBAL(j_close) != NULL)
                        ret = DB_GLOBAL(j_close)(fhp->fd);
                else if (fhp->handle != INVALID_HANDLE_VALUE)
                        RETRY_CHK((!CloseHandle(fhp->handle)), ret);
                else
                        RETRY_CHK((_close(fhp->fd)), ret);

                if (ret != 0)
                        __db_err(dbenv, "CloseHandle: %s", strerror(ret));

                /* Unlink the file if we haven't already done so. */
                if (F_ISSET(fhp, DB_FH_UNLINK)) {
                        (void)__os_unlink(dbenv, fhp->name);
                        __os_free(dbenv, fhp->name);
                }
        }

        __os_free(dbenv, fhp);

        return (ret);
}

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