crypt.cc

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/* $Header: /var/cvs/mbdyn/mbdyn/mbdyn-1.0/libraries/libmbutil/crypt.cc,v 1.17 2017/01/12 14:44:04 masarati Exp $ */
/* 
 * MBDyn (C) is a multibody analysis code. 
 * http://www.mbdyn.org
 *
 * Copyright (C) 1996-2017
 *
 * Pierangelo Masarati  <masarati@aero.polimi.it>
 * Paolo Mantegazza     <mantegazza@aero.polimi.it>
 *
 * Dipartimento di Ingegneria Aerospaziale - Politecnico di Milano
 * via La Masa, 34 - 20156 Milano, Italy
 * http://www.aero.polimi.it
 *
 * Changing this copyright notice is forbidden.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation (version 2 of the License).
 * 
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "mbconfig.h"           /* This goes first in every *.c,*.cc file */

#include "myassert.h"
#include <stdlib.h>
#include <string.h>
#include "crypt.h"

char *
mbdyn_make_salt(char *salt, size_t saltlen, const char *salt_format)
{
        static char salt_charset[] =
                "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789./";

        ASSERT(strlen(salt_charset) == 64);
        ASSERT(salt);
        ASSERT(saltlen > 2);

        char    buf[34];

#if defined(HAVE_DEV_RANDOM) || defined(HAVE_DEV_URANDOM)
        FILE *fin = NULL;

#if defined(HAVE_DEV_RANDOM)
        fin = fopen("/dev/random");
#elif defined(HAVE_DEV_URANDOM)
        fin = fopen("/dev/urandom");
#endif /* HAVE_DEV_RANDOM || HAVE_DEV_URANDOM */

        fread(buf, STRLENOF(buf), 1, fin);
        buf[STRLENOF(buf)] = '\0';
        fclose(fin);

        for (unsigned int i = 0; i < STRLENOF(buf); i++) {
                buf[i] = salt_charset[buf[i] % STRLENOF(salt_charset)];
        }
#else
        for (unsigned int i = 0; i < STRLENOF(buf); i++) {
                buf[i] = salt_charset[rand() % STRLENOF(salt_charset)];
        }
#endif

        if (salt_format) {
                snprintf(salt, saltlen, salt_format, buf);
        } else {
                strncpy(salt, buf, saltlen);
        }

        return salt;
}