libcryptoutil/common/tohexstr.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/types.h>
#include <errno.h>
#include <ctype.h>

#include <cryptoutil.h>

/*
 * tohexstr
 * IN   bytes
 *  blen
 *  hexlen should be 2 * blen + 1
 * OUT
 *  hexstr
 */
void
tohexstr(uchar_t *bytes, size_t blen, char *hexstr, size_t hexlen)
{
    size_t i;
    char hexlist[] = "0123456789abcdef";

    for (i = 0; i < blen; i++) {
        if (hexlen < (2 * i + 1))
            break;
        hexstr[2 * i] = hexlist[(bytes[i] >> 4) & 0xf];
        hexstr[2 * i + 1] = hexlist[bytes[i] & 0xf];
    }
    hexstr[2 * blen] = '\0';
}

/*
 * This function takes a char[] and length of hexadecimal values and
 * returns a malloc'ed byte array with the length of that new byte array.
 * The caller needs to provide a pointer to where this new malloc'ed byte array
 * will be passed back; as well as, a pointer for the length of the new
 * byte array.
 *
 * The caller is responsible for freeing the malloc'ed array when done
 *
 * The return code is 0 if successful, otherwise the errno value is returned.
 */
int
hexstr_to_bytes(char *hexstr, size_t hexlen, uchar_t **bytes, size_t *blen)
{
    int i, ret = 0;
    unsigned char ch;
    uchar_t *b = NULL;

    *bytes = NULL;
    *blen = 0;

    if (hexstr == NULL || (hexlen % 2 == 1))
        return (EINVAL);

    if (hexstr[0] == '0' && ((hexstr[1] == 'x') || (hexstr[1] == 'X'))) {
        hexstr += 2;
        hexlen -= 2;
    }

    *blen = (hexlen / 2);

    b = malloc(*blen);
    if (b == NULL) {
        *blen = 0;
        return (errno);
    }

    for (i = 0; i < hexlen; i++) {
        ch = (unsigned char) *hexstr;

        if (!isxdigit(ch)) {
            ret = EINVAL;
            goto out;
        }

        hexstr++;

        if ((ch >= '0') && (ch <= '9'))
            ch -= '0';
        else if ((ch >= 'A') && (ch <= 'F'))
            ch = ch - 'A' + 10;
        else if ((ch >= 'a') && (ch <= 'f'))
            ch = ch - 'a' + 10;

        if (i & 1)
            b[i/2] |= ch;
        else
            b[i/2] = (ch << 4);
    }

out:
    if (b != NULL && ret != 0) {
        free(b);
        *blen = 0;
    } else
        *bytes = b;

    return (ret);
}