freebsd-dev/lib/libc/locale/lmonetary.c
Mark Johnston 7eb138a9e5 libc/locale: Fix races between localeconv(3) and setlocale(3)
Each locale embeds a lazily initialized lconv which is populated by
localeconv(3) and localeconv_l(3).  When setlocale(3) updates the global
locale, the lconv needs to be (lazily) reinitialized.  To signal this,
we set flag variables in the locale structure.  There are two problems:

- The flags are set before the locale is fully updated, so a concurrent
  localeconv() call can observe partially initialized locale data.
- No barriers ensure that localeconv() observes a fully initialized
  locale if a flag is set.

So, move the flag update appropriately, and use acq/rel barriers to
provide some synchronization.  Note that this is inadequate in the face
of multiple concurrent calls to setlocale(3), but this is not expected
to work regardless.

Thanks to Henry Hu <henry.hu.sh@gmail.com> for providing a test case
demonstrating the race.

PR:		258360
MFC after:	3 weeks
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D31899
2021-09-17 10:47:46 -04:00

228 lines
6.5 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2000, 2001 Alexey Zelkin <phantom@FreeBSD.org>
* All rights reserved.
*
* Copyright (c) 2011 The FreeBSD Foundation
* All rights reserved.
* Portions of this software were developed by David Chisnall
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <limits.h>
#include <stddef.h>
#include <stdlib.h>
#include "ldpart.h"
#include "lmonetary.h"
extern const char * __fix_locale_grouping_str(const char *);
#define LCMONETARY_SIZE_FULL (sizeof(struct lc_monetary_T) / sizeof(char *))
#define LCMONETARY_SIZE_MIN \
(offsetof(struct lc_monetary_T, int_p_cs_precedes) / \
sizeof(char *))
static char empty[] = "";
static char numempty[] = { CHAR_MAX, '\0'};
static const struct lc_monetary_T _C_monetary_locale = {
empty, /* int_curr_symbol */
empty, /* currency_symbol */
empty, /* mon_decimal_point */
empty, /* mon_thousands_sep */
numempty, /* mon_grouping */
empty, /* positive_sign */
empty, /* negative_sign */
numempty, /* int_frac_digits */
numempty, /* frac_digits */
numempty, /* p_cs_precedes */
numempty, /* p_sep_by_space */
numempty, /* n_cs_precedes */
numempty, /* n_sep_by_space */
numempty, /* p_sign_posn */
numempty, /* n_sign_posn */
numempty, /* int_p_cs_precedes */
numempty, /* int_n_cs_precedes */
numempty, /* int_p_sep_by_space */
numempty, /* int_n_sep_by_space */
numempty, /* int_p_sign_posn */
numempty /* int_n_sign_posn */
};
struct xlocale_monetary __xlocale_global_monetary;
static char
cnv(const char *str)
{
int i = strtol(str, NULL, 10);
if (i == -1)
i = CHAR_MAX;
return ((char)i);
}
static void
destruct_monetary(void *v)
{
struct xlocale_monetary *l = v;
if (l->buffer)
free(l->buffer);
free(l);
}
static int
monetary_load_locale_l(struct xlocale_monetary *loc, int *using_locale,
int *changed, const char *name)
{
int ret;
struct lc_monetary_T *l = &loc->locale;
ret = __part_load_locale(name, using_locale,
&loc->buffer, "LC_MONETARY",
LCMONETARY_SIZE_FULL, LCMONETARY_SIZE_MIN,
(const char **)l);
if (ret == _LDP_LOADED) {
l->mon_grouping =
__fix_locale_grouping_str(l->mon_grouping);
#define M_ASSIGN_CHAR(NAME) (((char *)l->NAME)[0] = \
cnv(l->NAME))
M_ASSIGN_CHAR(int_frac_digits);
M_ASSIGN_CHAR(frac_digits);
M_ASSIGN_CHAR(p_cs_precedes);
M_ASSIGN_CHAR(p_sep_by_space);
M_ASSIGN_CHAR(n_cs_precedes);
M_ASSIGN_CHAR(n_sep_by_space);
M_ASSIGN_CHAR(p_sign_posn);
M_ASSIGN_CHAR(n_sign_posn);
/*
* The six additional C99 international monetary formatting
* parameters default to the national parameters when
* reading FreeBSD LC_MONETARY data files.
*/
#define M_ASSIGN_ICHAR(NAME) \
do { \
if (l->int_##NAME == NULL) \
l->int_##NAME = \
l->NAME; \
else \
M_ASSIGN_CHAR(int_##NAME); \
} while (0)
M_ASSIGN_ICHAR(p_cs_precedes);
M_ASSIGN_ICHAR(n_cs_precedes);
M_ASSIGN_ICHAR(p_sep_by_space);
M_ASSIGN_ICHAR(n_sep_by_space);
M_ASSIGN_ICHAR(p_sign_posn);
M_ASSIGN_ICHAR(n_sign_posn);
}
if (ret != _LDP_ERROR)
atomic_store_rel_int(changed, 1);
return (ret);
}
int
__monetary_load_locale(const char *name)
{
return monetary_load_locale_l(&__xlocale_global_monetary,
&__xlocale_global_locale.using_monetary_locale,
&__xlocale_global_locale.monetary_locale_changed, name);
}
void* __monetary_load(const char *name, locale_t l)
{
struct xlocale_monetary *new = calloc(sizeof(struct xlocale_monetary), 1);
new->header.header.destructor = destruct_monetary;
if (monetary_load_locale_l(new, &l->using_monetary_locale,
&l->monetary_locale_changed, name) == _LDP_ERROR)
{
xlocale_release(new);
return NULL;
}
return new;
}
struct lc_monetary_T *
__get_current_monetary_locale(locale_t loc)
{
return (loc->using_monetary_locale
? &((struct xlocale_monetary*)loc->components[XLC_MONETARY])->locale
: (struct lc_monetary_T *)&_C_monetary_locale);
}
#ifdef LOCALE_DEBUG
void
monetdebug() {
printf( "int_curr_symbol = %s\n"
"currency_symbol = %s\n"
"mon_decimal_point = %s\n"
"mon_thousands_sep = %s\n"
"mon_grouping = %s\n"
"positive_sign = %s\n"
"negative_sign = %s\n"
"int_frac_digits = %d\n"
"frac_digits = %d\n"
"p_cs_precedes = %d\n"
"p_sep_by_space = %d\n"
"n_cs_precedes = %d\n"
"n_sep_by_space = %d\n"
"p_sign_posn = %d\n"
"n_sign_posn = %d\n"
"int_p_cs_precedes = %d\n"
"int_p_sep_by_space = %d\n"
"int_n_cs_precedes = %d\n"
"int_n_sep_by_space = %d\n"
"int_p_sign_posn = %d\n"
"int_n_sign_posn = %d\n",
_monetary_locale.int_curr_symbol,
_monetary_locale.currency_symbol,
_monetary_locale.mon_decimal_point,
_monetary_locale.mon_thousands_sep,
_monetary_locale.mon_grouping,
_monetary_locale.positive_sign,
_monetary_locale.negative_sign,
_monetary_locale.int_frac_digits[0],
_monetary_locale.frac_digits[0],
_monetary_locale.p_cs_precedes[0],
_monetary_locale.p_sep_by_space[0],
_monetary_locale.n_cs_precedes[0],
_monetary_locale.n_sep_by_space[0],
_monetary_locale.p_sign_posn[0],
_monetary_locale.n_sign_posn[0],
_monetary_locale.int_p_cs_precedes[0],
_monetary_locale.int_p_sep_by_space[0],
_monetary_locale.int_n_cs_precedes[0],
_monetary_locale.int_n_sep_by_space[0],
_monetary_locale.int_p_sign_posn[0],
_monetary_locale.int_n_sign_posn[0]
);
}
#endif /* LOCALE_DEBUG */