/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2007 Diomidis Spinellis
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/types.h>
#include <sys/acct.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <db.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

#include "extern.h"

/* Key used to store the version of the database data elements. */
static char VERSION_KEY[] = "\0VERSION";

/*
 * Create the in-memory database, *mdb.
 * If iflag is not set, fill-in mdb with the records of the disk-based
 * database dbname.
 * Upgrade old-version records by calling v1_to_v2.
 * Return 0 if OK, -1 on error.
 */
int
db_copy_in(DB **mdb, const char *dbname, const char *uname, BTREEINFO *bti,
    int (*v1_to_v2)(DBT *key, DBT *data))
{
        DBT key, data;
        DB *ddb;
        int error, rv, version;

        if ((*mdb = dbopen(NULL, O_RDWR, 0, DB_BTREE, bti)) == NULL)
                return (-1);

        if (iflag)
                return (0);

        if ((ddb = dbopen(dbname, O_RDONLY, 0, DB_BTREE, bti)) == NULL) {
                if (errno == ENOENT)
                        return (0);
                warn("retrieving %s summary", uname);
                db_destroy(*mdb, uname);
                return (-1);
        }

        error = 0;

        /* Obtain/set version. */
        version = 1;
        key.data = (void*)&VERSION_KEY;
        key.size = sizeof(VERSION_KEY);

        rv = DB_GET(ddb, &key, &data, 0);
        if (rv < 0) {
                warn("get version key from %s stats", uname);
                error = -1;
                goto closeout;
        } else if (rv == 0) {   /* It's there; verify version. */
                if (data.size != sizeof(version)) {
                        warnx("invalid version size %zd in %s",
                            data.size, uname);
                        error = -1;
                        goto closeout;
                }
                memcpy(&version, data.data, data.size);
                if (version != 2) {
                        warnx("unsupported version %d in %s",
                            version, uname);
                        error = -1;
                        goto closeout;
                }
        }

        for (rv = DB_SEQ(ddb, &key, &data, R_FIRST); rv == 0;
            rv = DB_SEQ(ddb, &key, &data, R_NEXT)) {

                /* See if this is a version record. */
                if (key.size == sizeof(VERSION_KEY) &&
                    memcmp(key.data, VERSION_KEY, sizeof(VERSION_KEY)) == 0)
                        continue;

                /* Convert record from v1, if needed. */
                if (version == 1 && v1_to_v2(&key, &data) < 0) {
                        warn("converting %s stats", uname);
                        error = -1;
                        goto closeout;
                }

                /* Copy record to the in-memory database. */
                if ((rv = DB_PUT(*mdb, &key, &data, 0)) < 0) {
                        warn("initializing %s stats", uname);
                        error = -1;
                        goto closeout;
                }
        }
        if (rv < 0) {
                warn("retrieving %s summary", uname);
                error = -1;
        }

closeout:
        if (DB_CLOSE(ddb) < 0) {
                warn("closing %s summary", uname);
                error = -1;
        }

        if (error)
                db_destroy(*mdb, uname);
        return (error);
}

/*
 * Save the in-memory database mdb to the disk database dbname.
 * Return 0 if OK, -1 on error.
 */
int
db_copy_out(DB *mdb, const char *dbname, const char *uname, BTREEINFO *bti)
{
        DB *ddb;
        DBT key, data;
        int error, rv, version;

        if ((ddb = dbopen(dbname, O_RDWR|O_CREAT|O_TRUNC, 0644,
            DB_BTREE, bti)) == NULL) {
                warn("creating %s summary", uname);
                return (-1);
        }

        error = 0;

        for (rv = DB_SEQ(mdb, &key, &data, R_FIRST);
            rv == 0; rv = DB_SEQ(mdb, &key, &data, R_NEXT)) {
                if ((rv = DB_PUT(ddb, &key, &data, 0)) < 0) {
                        warn("saving %s summary", uname);
                        error = -1;
                        goto out;
                }
        }
        if (rv < 0) {
                warn("retrieving %s stats", uname);
                error = -1;
        }

out:
        /* Add a version record. */
        key.data = (void*)&VERSION_KEY;
        key.size = sizeof(VERSION_KEY);
        version = 2;
        data.data = &version;
        data.size = sizeof(version);
        if ((rv = DB_PUT(ddb, &key, &data, 0)) < 0) {
                warn("add version record to %s stats", uname);
                error = -1;
        } else if (rv == 1) {
                warnx("duplicate version record in %s stats", uname);
                error = -1;
        }

        if (DB_SYNC(ddb, 0) < 0) {
                warn("syncing %s summary", uname);
                error = -1;
        }
        if (DB_CLOSE(ddb) < 0) {
                warn("closing %s summary", uname);
                error = -1;
        }
        return error;
}

void
db_destroy(DB *db, const char *uname)
{
        if (DB_CLOSE(db) < 0)
                warn("destroying %s stats", uname);
}