duplocale: protect use of global locale (bug 23970)
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Commit Message
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.
---
locale/duplocale.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
Comments
On 3/6/24 07:48, Andreas Schwab wrote:
> 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.
Agreed. Good catch, we should make this work.
LGTM.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> locale/duplocale.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/locale/duplocale.c b/locale/duplocale.c
> index a755ac5c36..bad476700f 100644
> --- a/locale/duplocale.c
> +++ b/locale/duplocale.c
> @@ -43,6 +43,11 @@ __duplocale (locale_t dataset)
> 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)
> @@ -55,9 +60,6 @@ __duplocale (locale_t dataset)
> {
> char *namep = (char *) (result + 1);
>
> - /* We modify global data (the usage counts). */
> - __libc_rwlock_wrlock (__libc_setlocale_lock);
> -
> for (cnt = 0; cnt < __LC_LAST; ++cnt)
> if (cnt != LC_ALL)
> {
> @@ -78,11 +80,11 @@ __duplocale (locale_t dataset)
> 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);
> }
>
> + /* It's done. */
> + __libc_rwlock_unlock (__libc_setlocale_lock);
> +
> return result;
> }
> weak_alias (__duplocale, duplocale)
@@ -43,6 +43,11 @@ __duplocale (locale_t dataset)
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)
@@ -55,9 +60,6 @@ __duplocale (locale_t dataset)
{
char *namep = (char *) (result + 1);
- /* We modify global data (the usage counts). */
- __libc_rwlock_wrlock (__libc_setlocale_lock);
-
for (cnt = 0; cnt < __LC_LAST; ++cnt)
if (cnt != LC_ALL)
{
@@ -78,11 +80,11 @@ __duplocale (locale_t dataset)
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);
}
+ /* It's done. */
+ __libc_rwlock_unlock (__libc_setlocale_lock);
+
return result;
}
weak_alias (__duplocale, duplocale)