/*------------------------------------------------------------------ * wcsncat_s.c * * September 2017, Reini Urban * * Copyright (c) 2017 by Reini Urban * All rights reserved. * * Permission is hereby granted, free of charge, to any person * obtaining a copy of this software and associated documentation * files (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, * copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following * conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. *------------------------------------------------------------------ */ #ifdef FOR_DOXYGEN #include "safe_str_lib.h" #else #include "safeclib_private.h" #endif #if (defined(TEST_MSVCRT) && defined(HAVE_WCSNCAT_S)) || !defined(HAVE_WCHAR_H) #else /** * @def wcsncat_s(dest,dmax,src,slen) * @brief * The \b wcsncat_s function appends a copy of the wide string pointed * to by src (including the terminating null wide character) to the * end of the wide string pointed to by dest. The initial character * from src overwrites the null wide character at the end of dest. * @details * All elements following the terminating null wide character (if * any) written by wcsncat_s in the array of dmax wide characters * pointed to by dest take unspeciļ¬ed values when wcsncat_s returns. * With SAFECLIB_STR_NULL_SLACK defined the rest is cleared with * 0. * * @remark SPECIFIED IN * * C11 standard (ISO/IEC 9899:2011): * K.3.9.2.2.2 The wcsncat_s function (p: 643-644) * http://en.cppreference.com/w/c/string/wide/wcsncat * * ISO/IEC TR 24731, Programming languages, environments * and system software interfaces, Extensions to the C Library, * Part I: Bounds-checking interfaces * * @param[out] dest pointer to wide string that will be extended by src * if dmax allows. The string is null terminated. * If the resulting concatenated wide string is less * than dmax, the remaining slack space is nulled. * @param[in] dmax restricted maximum length of the resulting dest, * including the null * @param[in] src pointer to the wide string that will be concatenaed * to string dest * @param[in] slen maximum wide characters to append * * @pre Neither dest nor src shall be a null pointer. * @pre dmax shall not equal zero. * @pre dmax shall not be greater than RSIZE_MAX_WSTR and size of dest. * @pre dmax shall be greater than wcsnlen_s(src,slen). * @pre Copying shall not take place between objects that overlap. * * @note C11 uses RSIZE_MAX, not RSIZE_MAX_WSTR. * * @note The Windows MSVCRT sec_api EINVAL and ERANGE works ok, * ESLEMAX dmax/slen>MAX not, ESOVRLP partially. When dest>src Windows * appends the result, when dest 0 * @retval ESZEROL when dmax = 0 and slen > 0 * @retval ESLEMAX when dmax/slen > RSIZE_MAX_WSTR and slen > 0 * @retval EOVERFLOW when dmax/slen > size of dest/src (optionally, when the * compiler knows the object_size statically) * @retval ESLEWRNG when dmax != size of dest and --enable-error-dmax * @retval ESUNTERM when dest not terminated and slen > 0 * @retval ESOVRLP when src overlaps with dest and slen > 0 * * @see * wcscat_s(), strncat_s() */ #ifdef FOR_DOXYGEN errno_t wcsncat_s(wchar_t *restrict dest, rsize_t dmax, const wchar_t *restrict src, rsize_t slen) #else EXPORT errno_t _wcsncat_s_chk(wchar_t *restrict dest, rsize_t dmax, const wchar_t *restrict src, rsize_t slen, const size_t destbos, const size_t srcbos) #endif { rsize_t orig_dmax; wchar_t *orig_dest; const wchar_t *overlap_bumper; const size_t destsz = dmax * sizeof(wchar_t); if (unlikely(slen == 0 && !dest && !dmax)) { /* silent ok as in the msvcrt */ return EOK; } CHK_DEST_NULL("wcsncat_s") CHK_DMAX_ZERO("wcsncat_s") if (destbos == BOS_UNKNOWN) { CHK_DMAX_MAX("wcsncat_s", RSIZE_MAX_WSTR) BND_CHK_PTR_BOUNDS(dest, destsz); } else { CHK_DESTW_OVR("wcsncat_s", destsz, destbos) } CHK_SRCW_NULL_CLEAR("wcsncat_s", src) if (unlikely(slen > RSIZE_MAX_WSTR)) { handle_werror(dest, wcsnlen_s(dest, dmax), "wcsncat_s: slen exceeds max", ESLEMAX); return RCNEGATE(ESLEMAX); } if (srcbos == BOS_UNKNOWN) { BND_CHK_PTR_BOUNDS(src, slen * sizeof(wchar_t)); } else { if (unlikely(slen * sizeof(wchar_t) > srcbos)) { handle_werror(dest, wcsnlen_s(dest, dmax), "wcsncat_s: slen exceeds src", EOVERFLOW); return RCNEGATE(EOVERFLOW); } } if (unlikely(slen == 0)) { /* Special case, analog to msvcrt: when dest is big enough return EOK, but clear dest. */ errno_t error = (wcsnlen_s(dest, dmax) < dmax) ? EOK : ESZEROL; handle_werror(dest, dmax, "wcsncat_s: slen is 0", error); return RCNEGATE(error); } /* hold base of dest in case src was not copied */ orig_dmax = dmax; orig_dest = dest; if (dest < src) { overlap_bumper = src; /* Find the end of dest */ while (*dest != L'\0') { if (unlikely(dest == overlap_bumper)) { handle_werror(orig_dest, orig_dmax, "wcsncat_s: " "overlapping objects", ESOVRLP); return RCNEGATE(ESOVRLP); } dest++; dmax--; if (unlikely(dmax == 0)) { handle_werror(orig_dest, orig_dmax, "wcsncat_s: " "dest unterminated", ESUNTERM); return RCNEGATE(ESUNTERM); } } while (dmax > 0) { if (unlikely(dest == overlap_bumper)) { handle_werror(orig_dest, orig_dmax, "wcsncat_s: " "overlapping objects", ESOVRLP); return RCNEGATE(ESOVRLP); } /* * Copying truncated before the source null is encountered */ if (unlikely(slen == 0)) { #ifdef SAFECLIB_STR_NULL_SLACK /* null remaining string */ if (dmax > 0x20) memset(dest, 0, dmax * sizeof(wchar_t)); else { while (dmax) { *dest = L'\0'; dmax--; dest++; } } #else *dest = L'\0'; #endif return RCNEGATE(EOK); } *dest = *src; if (unlikely(*dest == L'\0')) { #ifdef SAFECLIB_STR_NULL_SLACK /* null slack to clear data */ if (dmax > 0x20) memset(dest, 0, dmax * sizeof(wchar_t)); else { while (dmax) { *dest = L'\0'; dmax--; dest++; } } #endif return RCNEGATE(EOK); } dmax--; slen--; dest++; src++; } } else { overlap_bumper = dest; /* Find the end of dest */ while (*dest != L'\0') { /* * NOTE: no need to check for overlap here since src comes first * in memory and we're not incrementing src here. */ dest++; dmax--; if (unlikely(dmax == 0)) { handle_werror(orig_dest, orig_dmax, "wcsncat_s: " "dest unterminated", ESUNTERM); return RCNEGATE(ESUNTERM); } } while (dmax > 0) { if (unlikely(src == overlap_bumper)) { handle_werror(orig_dest, orig_dmax, "wcsncat_s: " "overlapping objects", ESOVRLP); return RCNEGATE(ESOVRLP); } /* * Copying truncated */ if (unlikely(slen == 0)) { #ifdef SAFECLIB_STR_NULL_SLACK /* null remaining string */ if (dmax > 0x20) memset(dest, 0, dmax * sizeof(wchar_t)); else { while (dmax) { *dest = L'\0'; dmax--; dest++; } } #else *dest = L'\0'; #endif return RCNEGATE(EOK); } *dest = *src; if (unlikely(*dest == L'\0')) { #ifdef SAFECLIB_STR_NULL_SLACK /* null slack to clear any data */ if (dmax > 0x20) memset(dest, 0, dmax * sizeof(wchar_t)); else { while (dmax) { *dest = L'\0'; dmax--; dest++; } } #endif return RCNEGATE(EOK); } dmax--; slen--; dest++; src++; } } /* * the entire src was not copied, so the string will be nulled. */ handle_werror(orig_dest, orig_dmax, "wcsncat_s: not enough " "space for src", ESNOSPC); return RCNEGATE(ESNOSPC); } #endif /* HAVE_WCHAR_H */