libmeta/common/meta_stat.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1992, 1993, 1994, 2000 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * Caching stat function
 */

#include <meta.h>

#define MD_NUM_STAT_HEAD    16

struct statcache {
    struct statcache    *sc_next;
    struct stat     sc_stat;
    char            *sc_filename;
};

static struct statcache *statcache_head[MD_NUM_STAT_HEAD] =
    {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

int
meta_stat(const char *filename, struct stat *sbp)
{
    struct statcache    *scp;
    int          hash;
    char            *cp;

    hash = 0;
    for (cp = (char *)filename; *cp != 0; cp++)
        hash += *cp;

    hash &= 0xf;

    for (scp = statcache_head[hash]; scp != NULL; scp = scp->sc_next)
        if (strcmp(filename, scp->sc_filename) == 0)
            break;
    if (scp) {
        (void) memcpy((caddr_t)sbp, (caddr_t)&scp->sc_stat,
            sizeof (*sbp));
        return (0);
    }
    if (stat(filename, sbp) != 0)
        return (-1);

    if (!S_ISBLK(sbp->st_mode) && !S_ISCHR(sbp->st_mode))
        return (-1);

    scp = (struct statcache *)malloc(sizeof (*scp));
    if (scp != NULL) {
        (void) memcpy((caddr_t)&scp->sc_stat, (caddr_t)sbp,
            sizeof (*sbp));
        scp->sc_filename = strdup(filename);
        if (scp->sc_filename == NULL) {
            free((char *)scp);
            return (0);
        }
        scp->sc_next = statcache_head[hash];
        statcache_head[hash] = scp;
    }
    return (0);
}

void
metaflushstatcache(void)
{
    struct statcache    *p, *n;
    int         i;

    for (i = 0; i < MD_NUM_STAT_HEAD; i++) {
        for (p = statcache_head[i], n = NULL; p != NULL; p = n) {
            n = p->sc_next;
            Free(p->sc_filename);
            Free(p);
        }
        statcache_head[i] = NULL;
    }
}