1  /* Copyright (C) 1996-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <assert.h>
      19  #include <dlfcn.h>
      20  #include <errno.h>
      21  #include <gconv.h>
      22  #include <wchar.h>
      23  #include <wcsmbsload.h>
      24  
      25  #include <pointer_guard.h>
      26  
      27  #ifndef EILSEQ
      28  # define EILSEQ EINVAL
      29  #endif
      30  
      31  
      32  /* This is the private state used if PS is NULL.  */
      33  static mbstate_t state;
      34  
      35  /* This is a non-standard function but it is very useful in the
      36     implementation of stdio because we have to deal with unterminated
      37     buffers.  At most NWC wide character will be converted.  */
      38  size_t
      39  __wcsnrtombs (char *dst, const wchar_t **src, size_t nwc, size_t len,
      40  	      mbstate_t *ps)
      41  {
      42    struct __gconv_step_data data;
      43    const wchar_t *srcend;
      44    int status;
      45    size_t result;
      46    struct __gconv_step *tomb;
      47    const struct gconv_fcts *fcts;
      48  
      49    /* Tell where we want the result.  */
      50    data.__invocation_counter = 0;
      51    data.__internal_use = 1;
      52    data.__flags = __GCONV_IS_LAST;
      53    data.__statep = ps ?: &state;
      54  
      55    if (nwc == 0)
      56      return 0;
      57    srcend = *src + __wcsnlen (*src, nwc - 1) + 1;
      58  
      59    /* Get the conversion functions.  */
      60    fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
      61  
      62    /* Get the structure with the function pointers.  */
      63    tomb = fcts->tomb;
      64    __gconv_fct fct = tomb->__fct;
      65    if (tomb->__shlib_handle != NULL)
      66      PTR_DEMANGLE (fct);
      67  
      68    /* We have to handle DST == NULL special.  */
      69    if (dst == NULL)
      70      {
      71        mbstate_t temp_state;
      72        unsigned char buf[256];		/* Just an arbitrary value.  */
      73        const unsigned char *inbuf = (const unsigned char *) *src;
      74        size_t dummy;
      75  
      76        temp_state = *data.__statep;
      77        data.__statep = &temp_state;
      78  
      79        result = 0;
      80        data.__outbufend = buf + sizeof (buf);
      81  
      82        do
      83  	{
      84  	  data.__outbuf = buf;
      85  
      86  	  status = DL_CALL_FCT (fct, (tomb, &data, &inbuf,
      87  				      (const unsigned char *) srcend, NULL,
      88  				      &dummy, 0, 1));
      89  
      90  	  /* Count the number of bytes.  */
      91  	  result += data.__outbuf - buf;
      92  	}
      93        while (status == __GCONV_FULL_OUTPUT);
      94  
      95        if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
      96  	  && data.__outbuf[-1] == '\0')
      97  	/* Don't count the NUL character in.  */
      98  	--result;
      99      }
     100    else
     101      {
     102        /* This code is based on the safe assumption that all internal
     103  	 multi-byte encodings use the NUL byte only to mark the end
     104  	 of the string.  */
     105        size_t dummy;
     106  
     107        data.__outbuf = (unsigned char *) dst;
     108        data.__outbufend = (unsigned char *) dst + len;
     109  
     110        status = DL_CALL_FCT (fct, (tomb, &data, (const unsigned char **) src,
     111  				  (const unsigned char *) srcend, NULL,
     112  				  &dummy, 0, 1));
     113  
     114        /* Count the number of bytes.  */
     115        result = data.__outbuf - (unsigned char *) dst;
     116  
     117        /* We have to determine whether the last character converted
     118  	 is the NUL character.  */
     119        if ((status == __GCONV_OK || status == __GCONV_EMPTY_INPUT)
     120  	  && data.__outbuf[-1] == '\0')
     121  	{
     122  	  assert (data.__outbuf != (unsigned char *) dst);
     123  	  assert (__mbsinit (data.__statep));
     124  	  *src = NULL;
     125  	  --result;
     126  	}
     127      }
     128  
     129    /* There must not be any problems with the conversion but illegal input
     130       characters.  */
     131    assert (status == __GCONV_OK || status == __GCONV_EMPTY_INPUT
     132  	  || status == __GCONV_ILLEGAL_INPUT
     133  	  || status == __GCONV_INCOMPLETE_INPUT
     134  	  || status == __GCONV_FULL_OUTPUT);
     135  
     136    if (status != __GCONV_OK && status != __GCONV_FULL_OUTPUT
     137        && status != __GCONV_EMPTY_INPUT)
     138      {
     139        result = (size_t) -1;
     140        __set_errno (EILSEQ);
     141      }
     142  
     143    return result;
     144  }
     145  weak_alias (__wcsnrtombs, wcsnrtombs)