locale/duplocale.c

   1 /* Duplicate handle for selection of locales.
   2    Copyright (C) 1997-2024 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   /* If dataset points to _nl_global_locale, we need to prevent other
  47      threads from modifying it.  We also modify global data below (the
  48      usage counts).  */
  49   __libc_rwlock_wrlock (__libc_setlocale_lock);
  50
  51   /* Calculate the total space we need to store all the names.  */
  52   for (cnt = 0; cnt < __LC_LAST; ++cnt)
  53     if (cnt != LC_ALL && dataset->__names[cnt] != _nl_C_name)
  54       names_len += strlen (dataset->__names[cnt]) + 1;
  55
  56   /* Get memory.  */
  57   result = malloc (sizeof (struct __locale_struct) + names_len);
  58
  59   if (result != NULL)
  60     {
  61       char *namep = (char *) (result + 1);
  62
  63       for (cnt = 0; cnt < __LC_LAST; ++cnt)
  64         if (cnt != LC_ALL)
  65           {
  66             result->__locales[cnt] = dataset->__locales[cnt];
  67             if (result->__locales[cnt]->usage_count < MAX_USAGE_COUNT)
  68               ++result->__locales[cnt]->usage_count;
  69
  70             if (dataset->__names[cnt] == _nl_C_name)
  71               result->__names[cnt] = _nl_C_name;
  72             else
  73               {
  74                 result->__names[cnt] = namep;
  75                 namep = __stpcpy (namep, dataset->__names[cnt]) + 1;
  76               }
  77           }
  78
  79       /* Update the special members.  */
  80       result->__ctype_b = dataset->__ctype_b;
  81       result->__ctype_tolower = dataset->__ctype_tolower;
  82       result->__ctype_toupper = dataset->__ctype_toupper;
  83     }
  84
  85   /* It's done.  */
  86   __libc_rwlock_unlock (__libc_setlocale_lock);
  87
  88   return result;
  89 }
  90 weak_alias (__duplocale, duplocale)