locale/duplocale.c

   1 /* Duplicate handle for selection of locales.
   2    Copyright (C) 1997-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <locale.h>
  20 #include <libc-lock.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23
  24 #include <localeinfo.h>
  25
  26
  27 /* Lock for protecting global data.  */
  28 __libc_rwlock_define (extern , __libc_setlocale_lock attribute_hidden)
  29
  30
  31 locale_t
  32 __duplocale (locale_t dataset)
  33 {
  34   /* This static object is returned for newlocale (LC_ALL_MASK, "C").  */
  35   if (dataset == _nl_C_locobj_ptr)
  36     return dataset;
  37
  38   /* Handle a special value.  */
  39   if (dataset == LC_GLOBAL_LOCALE)
  40     dataset = &_nl_global_locale;
  41
  42   locale_t result;
  43   int cnt;
  44   size_t names_len = 0;
  45
  46   /* Calculate the total space we need to store all the names.  */
  47   for (cnt = 0; cnt < __LC_LAST; ++cnt)
  48     if (cnt != LC_ALL && dataset->__names[cnt] != _nl_C_name)
  49       names_len += strlen (dataset->__names[cnt]) + 1;
  50
  51   /* Get memory.  */
  52   result = malloc (sizeof (struct __locale_struct) + names_len);
  53
  54   if (result != NULL)
  55     {
  56       char *namep = (char *) (result + 1);
  57
  58       /* We modify global data (the usage counts).  */
  59       __libc_rwlock_wrlock (__libc_setlocale_lock);
  60
  61       for (cnt = 0; cnt < __LC_LAST; ++cnt)
  62         if (cnt != LC_ALL)
  63           {
  64             result->__locales[cnt] = dataset->__locales[cnt];
  65             if (result->__locales[cnt]->usage_count < MAX_USAGE_COUNT)
  66               ++result->__locales[cnt]->usage_count;
  67
  68             if (dataset->__names[cnt] == _nl_C_name)
  69               result->__names[cnt] = _nl_C_name;
  70             else
  71               {
  72                 result->__names[cnt] = namep;
  73                 namep = __stpcpy (namep, dataset->__names[cnt]) + 1;
  74               }
  75           }
  76
  77       /* Update the special members.  */
  78       result->__ctype_b = dataset->__ctype_b;
  79       result->__ctype_tolower = dataset->__ctype_tolower;
  80       result->__ctype_toupper = dataset->__ctype_toupper;
  81
  82       /* It's done.  */
  83       __libc_rwlock_unlock (__libc_setlocale_lock);
  84     }
  85
  86   return result;
  87 }
  88 weak_alias (__duplocale, duplocale)