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glibc/locale/duplocale.c
Andreas Schwab 513331b788 duplocale: protect use of global locale (bug 23970)
Protect the global locale from being modified while we compute the size of
the locale category names.  That allows the use of the global locale in a
single thread, while all other threads use the thread safe locale
functions.
2024-03-11 09:52:59 +01:00

91 lines
2.7 KiB
C

/* Duplicate handle for selection of locales.
Copyright (C) 1997-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <locale.h>
#include <libc-lock.h>
#include <stdlib.h>
#include <string.h>
#include <localeinfo.h>
/* Lock for protecting global data. */
__libc_rwlock_define (extern , __libc_setlocale_lock attribute_hidden)
locale_t
__duplocale (locale_t dataset)
{
/* This static object is returned for newlocale (LC_ALL_MASK, "C"). */
if (dataset == _nl_C_locobj_ptr)
return dataset;
/* Handle a special value. */
if (dataset == LC_GLOBAL_LOCALE)
dataset = &_nl_global_locale;
locale_t result;
int cnt;
size_t names_len = 0;
/* If dataset points to _nl_global_locale, we need to prevent other
threads from modifying it. We also modify global data below (the
usage counts). */
__libc_rwlock_wrlock (__libc_setlocale_lock);
/* Calculate the total space we need to store all the names. */
for (cnt = 0; cnt < __LC_LAST; ++cnt)
if (cnt != LC_ALL && dataset->__names[cnt] != _nl_C_name)
names_len += strlen (dataset->__names[cnt]) + 1;
/* Get memory. */
result = malloc (sizeof (struct __locale_struct) + names_len);
if (result != NULL)
{
char *namep = (char *) (result + 1);
for (cnt = 0; cnt < __LC_LAST; ++cnt)
if (cnt != LC_ALL)
{
result->__locales[cnt] = dataset->__locales[cnt];
if (result->__locales[cnt]->usage_count < MAX_USAGE_COUNT)
++result->__locales[cnt]->usage_count;
if (dataset->__names[cnt] == _nl_C_name)
result->__names[cnt] = _nl_C_name;
else
{
result->__names[cnt] = namep;
namep = __stpcpy (namep, dataset->__names[cnt]) + 1;
}
}
/* Update the special members. */
result->__ctype_b = dataset->__ctype_b;
result->__ctype_tolower = dataset->__ctype_tolower;
result->__ctype_toupper = dataset->__ctype_toupper;
}
/* It's done. */
__libc_rwlock_unlock (__libc_setlocale_lock);
return result;
}
weak_alias (__duplocale, duplocale)