xref: /third_party/bounds_checking_function/src/strcat_s.c

/*
 * Copyright (c) Huawei Technologies Co., Ltd. 2014-2021. All rights reserved.
 * Licensed under Mulan PSL v2.
 * You can use this software according to the terms and conditions of the Mulan PSL v2.
 * You may obtain a copy of Mulan PSL v2 at:
 *          http://license.coscl.org.cn/MulanPSL2
 * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
 * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
 * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
 * See the Mulan PSL v2 for more details.
 * Description: strcat_s  function
 * Create: 2014-02-25
 */

#include "securecutil.h"

/*
 * Befor this function, the basic parameter checking has been done
 */
SECUREC_INLINE errno_t SecDoCat(char *strDest, size_t destMax, const char *strSrc)
{
    size_t destLen;
    size_t srcLen;
    size_t maxSrcLen;
    SECUREC_CALC_STR_LEN(strDest, destMax, &destLen);
    /* Only optimize strSrc, do not apply this function to strDest */
    maxSrcLen = destMax - destLen;
    SECUREC_CALC_STR_LEN_OPT(strSrc, maxSrcLen, &srcLen);

    if (SECUREC_CAT_STRING_IS_OVERLAP(strDest, destLen, strSrc, srcLen)) {
        strDest[0] = '\0';
        if (strDest + destLen <= strSrc && destLen == destMax) {
            SECUREC_ERROR_INVALID_PARAMTER("strcat_s");
            return EINVAL_AND_RESET;
        }
        SECUREC_ERROR_BUFFER_OVERLAP("strcat_s");
        return EOVERLAP_AND_RESET;
    }
    if (srcLen + destLen >= destMax || strDest == strSrc) {
        strDest[0] = '\0';
        if (destLen == destMax) {
            SECUREC_ERROR_INVALID_PARAMTER("strcat_s");
            return EINVAL_AND_RESET;
        }
        SECUREC_ERROR_INVALID_RANGE("strcat_s");
        return ERANGE_AND_RESET;
    }
    SECUREC_MEMCPY_WARP_OPT(strDest + destLen, strSrc, srcLen + 1); /* Single character length  include \0 */
    return EOK;
}

/*
 * <FUNCTION DESCRIPTION>
 *  The strcat_s function appends a copy of the string pointed to by strSrc (including the terminating null character)
 *  to the end of the  string pointed to by strDest.
 *  The initial character of strSrc overwrites the terminating null character of strDest.
 *  strcat_s will return EOVERLAP_AND_RESET if the source and destination strings overlap.
 *
 *  Note that the second parameter is the total size of the buffer, not the
 *  remaining size.
 *
 * <INPUT PARAMETERS>
 *  strDest             Null-terminated destination string buffer.
 *  destMax             Size of the destination string buffer.
 *  strSrc              Null-terminated source string buffer.
 *
 * <OUTPUT PARAMETERS>
 *    strDest             is updated
 *
 * <RETURN VALUE>
 *    EOK                 Success
 *    EINVAL              strDest is  NULL and destMax != 0 and destMax <= SECUREC_STRING_MAX_LEN
 *    EINVAL_AND_RESET    (strDest unterminated  and all other parameters are valid) or
 *                        (strDest != NULL and strSrc is NULL and destMax != 0 and destMax <= SECUREC_STRING_MAX_LEN)
 *    ERANGE              destMax is 0 and destMax > SECUREC_STRING_MAX_LEN
 *    ERANGE_AND_RESET      strDest have not enough space  and all other parameters are valid  and not overlap
 *    EOVERLAP_AND_RESET   dest buffer and source buffer are overlapped and all  parameters are valid
 *
 *    If there is a runtime-constraint violation, strDest[0] will be set to the '\0' when strDest and destMax valid
 */
errno_t strcat_s(char *strDest, size_t destMax, const char *strSrc)
{
    if (destMax == 0 || destMax > SECUREC_STRING_MAX_LEN) {
        SECUREC_ERROR_INVALID_RANGE("strcat_s");
        return ERANGE;
    }
    if (strDest == NULL || strSrc == NULL) {
        SECUREC_ERROR_INVALID_PARAMTER("strcat_s");
        if (strDest != NULL) {
            strDest[0] = '\0';
            return EINVAL_AND_RESET;
        }
        return EINVAL;
    }
    return SecDoCat(strDest, destMax, strSrc);
}

#if SECUREC_EXPORT_KERNEL_SYMBOL
EXPORT_SYMBOL(strcat_s);
#endif