clamav/libclamav/uniq.c

/*
 *  md5 based hashtab
 *
 *  Copyright (C) 2013-2019 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 *  Copyright (C) 2008-2013 Sourcefire, Inc.
 *
 *  Authors: aCaB <acab@clamav.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 *  MA 02110-1301, USA.
 */

#if HAVE_CONFIG_H
#include "clamav-config.h"
#endif

#include <stdlib.h>
#if HAVE_STRING_H
#include <string.h>
#endif

#include "clamav.h"
#include "uniq.h"
#include "others.h"

struct uniq *uniq_init(uint32_t count)
{
    struct uniq *U;

    if (!count) return NULL;
    U = cli_calloc(1, sizeof(*U));
    if (!U) return NULL;

    U->md5s = cli_malloc(count * sizeof(*U->md5s));
    if (!U->md5s) {
        uniq_free(U);
        return NULL;
    }

    return U;
}

void uniq_free(struct uniq *U)
{
    free(U->md5s);
    free(U);
}

uint32_t uniq_add(struct uniq *U, const char *key, uint32_t key_len, char **rhash)
{
    unsigned int i;
    uint8_t digest[16];
    struct UNIQMD5 *m = NULL;

    cl_hash_data("md5", key, key_len, digest, NULL);

    if (U->items && U->md5s[U->idx[*digest]].md5[0] == *digest)
        for (m = &U->md5s[U->idx[*digest]]; m; m = m->next)
            if (!memcmp(&digest[1], &m->md5[1], 15)) break;

    if (!m) {
        const char HEX[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

        m        = &U->md5s[U->items];
        m->count = 0;

        if (U->items && U->md5s[U->idx[*digest]].md5[0] == *digest)
            m->next = &U->md5s[U->idx[*digest]];
        else
            m->next = NULL;

        U->idx[*digest] = U->items;

        for (i = 0; i < 16; i++) {
            m->name[i * 2]     = HEX[digest[i] >> 4 & 0xf];
            m->name[i * 2 + 1] = HEX[digest[i] & 0xf];
            m->md5[i]          = digest[i];
        }
        m->name[32] = '\0';
    }

    U->items++;
    if (rhash) *rhash = m->name;
    return m->count++;
}

uint32_t uniq_get(struct uniq *U, const char *key, uint32_t key_len, char **rhash)
{
    uint8_t digest[16];
    struct UNIQMD5 *m = NULL;

    cl_hash_data("md5", key, key_len, digest, NULL);

    if (!U->items || U->md5s[U->idx[*digest]].md5[0] != *digest)
        return 0;

    for (m = &U->md5s[U->idx[*digest]]; m; m = m->next) {
        if (memcmp(&digest[1], &m->md5[1], 15)) continue;
        if (rhash) *rhash = m->name;
        return m->count;
    }

    return 0;
}