backends.c

/*
 * Copyright (c) 2014 Jan-Piet Mens <jpmens()gmail.com>
 * 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.
 * 3. Neither the name of mosquitto nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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 <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "backends.h"

/*
 * Search through `in' for tokens %c (clientid) and %u (username);
 * build a new malloc'd string at `res' with those tokens interpolated
 * into it.
 */

void t_expand(const char *clientid, const char *username, char *in, char **res)
{
        char *s, *work, *wp;
        int c_specials = 0, u_specials = 0, len;
        const char *ct, *ut;

        ct = (clientid) ? clientid : "";
        ut = (username) ? username : "";

        for (s = in; s && *s; s++) {
                if (*s == '%' && (*(s+1) == 'c'))
                        c_specials++;
                if (*s == '%' && (*(s+1) == 'u'))
                        u_specials++;
        }
        len = strlen(in) + 1;
        len += strlen(clientid) * c_specials;
        len += strlen(username) * u_specials;

        if ((work = malloc(len)) == NULL) {
                *res = NULL;
                return;
        }
        for (s = in, wp = work; s && *s; s++) {
                *wp++ = *s;
                if (*s == '%' && (*(s+1) == 'c')) {
                        *--wp = 0;
                        strcpy(wp, ct);
                        wp += strlen(ct);
                        s++;
                }
                if (*s == '%' && (*(s+1) == 'u')) {
                        *--wp = 0;
                        strcpy(wp, ut);
                        wp += strlen(ut);
                        s++;
                }
        }
        *wp = 0;

        *res = work;
}