db/mp/mp_open.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996, 1997, 1998
 *  Sleepycat Software.  All rights reserved.
 */
#include "config.h"

#ifndef lint
static const char sccsid[] = "@(#)mp_open.c 10.27 (Sleepycat) 10/1/98";
#endif /* not lint */

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

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

#include "db_int.h"
#include "shqueue.h"
#include "db_shash.h"
#include "mp.h"
#include "common_ext.h"

/*
 * memp_open --
 *  Initialize and/or join a memory pool.
 */
int
memp_open(path, flags, mode, dbenv, retp)
    const char *path;
    u_int32_t flags;
    int mode;
    DB_ENV *dbenv;
    DB_MPOOL **retp;
{
    DB_MPOOL *dbmp;
    size_t cachesize;
    int is_private, ret;

    /* Validate arguments. */
#ifdef HAVE_SPINLOCKS
#define OKFLAGS (DB_CREATE | DB_MPOOL_PRIVATE | DB_NOMMAP | DB_THREAD)
#else
#define OKFLAGS (DB_CREATE | DB_MPOOL_PRIVATE | DB_NOMMAP)
#endif
    if ((ret = __db_fchk(dbenv, "memp_open", flags, OKFLAGS)) != 0)
        return (ret);

    /* Extract fields from DB_ENV structure. */
    cachesize = dbenv == NULL ? 0 : dbenv->mp_size;

    /* Create and initialize the DB_MPOOL structure. */
    if ((ret = __os_calloc(1, sizeof(DB_MPOOL), &dbmp)) != 0)
        return (ret);
    LIST_INIT(&dbmp->dbregq);
    TAILQ_INIT(&dbmp->dbmfq);

    dbmp->dbenv = dbenv;

    /* Decide if it's possible for anyone else to access the pool. */
    is_private =
        (dbenv == NULL && path == NULL) || LF_ISSET(DB_MPOOL_PRIVATE);

    /*
     * Map in the region.  We do locking regardless, as portions of it are
     * implemented in common code (if we put the region in a file, that is).
     */
    F_SET(dbmp, MP_LOCKREGION);
    if ((ret = __memp_ropen(dbmp,
        path, cachesize, mode, is_private, LF_ISSET(DB_CREATE))) != 0)
        goto err;
    F_CLR(dbmp, MP_LOCKREGION);

    /*
     * If there's concurrent access, then we have to lock the region.
     * If it's threaded, then we have to lock both the handles and the
     * region, and we need to allocate a mutex for that purpose.
     */
    if (!is_private)
        F_SET(dbmp, MP_LOCKREGION);
    if (LF_ISSET(DB_THREAD)) {
        F_SET(dbmp, MP_LOCKHANDLE | MP_LOCKREGION);
        LOCKREGION(dbmp);
        ret = __memp_alloc(dbmp,
            sizeof(db_mutex_t), NULL, &dbmp->mutexp);
        UNLOCKREGION(dbmp);
        if (ret != 0) {
            (void)memp_close(dbmp);
            goto err;
        }
        LOCKINIT(dbmp, dbmp->mutexp);
    }

    *retp = dbmp;
    return (0);

err:    if (dbmp != NULL)
        __os_free(dbmp, sizeof(DB_MPOOL));
    return (ret);
}

/*
 * memp_close --
 *  Close a memory pool.
 */
int
memp_close(dbmp)
    DB_MPOOL *dbmp;
{
    DB_MPOOLFILE *dbmfp;
    DB_MPREG *mpreg;
    int ret, t_ret;

    ret = 0;

    MP_PANIC_CHECK(dbmp);

    /* Discard DB_MPREGs. */
    while ((mpreg = LIST_FIRST(&dbmp->dbregq)) != NULL) {
        LIST_REMOVE(mpreg, q);
        __os_free(mpreg, sizeof(DB_MPREG));
    }

    /* Discard DB_MPOOLFILEs. */
    while ((dbmfp = TAILQ_FIRST(&dbmp->dbmfq)) != NULL)
        if ((t_ret = memp_fclose(dbmfp)) != 0 && ret == 0)
            ret = t_ret;

    /* Discard thread mutex. */
    if (F_ISSET(dbmp, MP_LOCKHANDLE)) {
        LOCKREGION(dbmp);
        __db_shalloc_free(dbmp->addr, dbmp->mutexp);
        UNLOCKREGION(dbmp);
    }

    /* Close the region. */
    if ((t_ret = __db_rdetach(&dbmp->reginfo)) != 0 && ret == 0)
        ret = t_ret;

    if (dbmp->reginfo.path != NULL)
        __os_freestr(dbmp->reginfo.path);
    __os_free(dbmp, sizeof(DB_MPOOL));

    return (ret);
}

/*
 * __memp_panic --
 *  Panic a memory pool.
 *
 * PUBLIC: void __memp_panic __P((DB_ENV *));
 */
void
__memp_panic(dbenv)
    DB_ENV *dbenv;
{
    if (dbenv->mp_info != NULL)
        dbenv->mp_info->mp->rlayout.panic = 1;
}

/*
 * memp_unlink --
 *  Exit a memory pool.
 */
int
memp_unlink(path, force, dbenv)
    const char *path;
    int force;
    DB_ENV *dbenv;
{
    REGINFO reginfo;
    int ret;

    memset(&reginfo, 0, sizeof(reginfo));
    reginfo.dbenv = dbenv;
    reginfo.appname = DB_APP_NONE;
    if (path != NULL && (ret = __os_strdup(path, &reginfo.path)) != 0)
        return (ret);
    reginfo.file = DB_DEFAULT_MPOOL_FILE;
    ret = __db_runlink(&reginfo, force);
    if (reginfo.path != NULL)
        __os_freestr(reginfo.path);
    return (ret);
}

/*
 * memp_register --
 *  Register a file type's pgin, pgout routines.
 */
int
memp_register(dbmp, ftype, pgin, pgout)
    DB_MPOOL *dbmp;
    int ftype;
    int (*pgin) __P((db_pgno_t, void *, DBT *));
    int (*pgout) __P((db_pgno_t, void *, DBT *));
{
    DB_MPREG *mpr;
    int ret;

    MP_PANIC_CHECK(dbmp);

    if ((ret = __os_malloc(sizeof(DB_MPREG), NULL, &mpr)) != 0)
        return (ret);

    mpr->ftype = ftype;
    mpr->pgin = pgin;
    mpr->pgout = pgout;

    /*
     * Insert at the head.  Because we do a linear walk, we'll find
     * the most recent registry in the case of multiple entries, so
     * we don't have to check for multiple registries.
     */
    LOCKHANDLE(dbmp, dbmp->mutexp);
    LIST_INSERT_HEAD(&dbmp->dbregq, mpr, q);
    UNLOCKHANDLE(dbmp, dbmp->mutexp);

    return (0);
}