/*      $OpenBSD: forward.c,v 1.40 2021/06/14 17:58:15 eric Exp $       */

/*
 * Copyright (c) 2008 Gilles Chehade <gilles@poolp.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/stat.h>

#include <stdlib.h>
#include <util.h>
#include <unistd.h>

#include "smtpd.h"
#include "log.h"

#define MAX_FORWARD_SIZE        (4 * 1024)
#define MAX_EXPAND_NODES        (100)

int
forwards_get(int fd, struct expand *expand)
{
        FILE           *fp = NULL;
        char           *line = NULL;
        size_t          len;
        size_t          lineno;
        size_t          save;
        int             ret;
        struct stat     sb;

        ret = -1;
        if (fstat(fd, &sb) == -1)
                goto end;

        /* if it's empty just pretend that no expansion took place */
        if (sb.st_size == 0) {
                log_info("info: forward file is empty");
                ret = 0;
                goto end;
        }

        /* over MAX_FORWARD_SIZE, temporarily fail */
        if (sb.st_size >= MAX_FORWARD_SIZE) {
                log_info("info: forward file exceeds max size");
                goto end;
        }

        if ((fp = fdopen(fd, "r")) == NULL) {
                log_warn("warn: fdopen failure in forwards_get()");
                goto end;
        }

        lineno = 0;
        save = expand->nb_nodes;
        while ((line = fparseln(fp, &len, &lineno, NULL, 0)) != NULL) {
                if (!expand_line(expand, line, 0)) {
                        log_info("info: parse error in forward file");
                        goto end;
                }
                if (expand->nb_nodes > MAX_EXPAND_NODES) {
                        log_info("info: forward file expanded too many nodes");
                        goto end;
                }
                free(line);
        }

        ret = expand->nb_nodes > save ? 1 : 0;

end:
        free(line);
        if (fp)
                fclose(fp);
        else
                close(fd);
        return ret;
}