[PATCH alsa-lib 1/2] Check for thread-specific locale support

[PATCH alsa-lib 1/2] Check for thread-specific locale support

[Rémi Denis-Courmont]

---
 configure.in |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/configure.in b/configure.in
index f6df502..abc4687 100644
--- a/configure.in
+++ b/configure.in
@@ -64,6 +64,7 @@ dnl Checks for library functions.
 AC_PROG_GCC_TRADITIONAL
 AC_CHECK_FUNC([hsearch_r], [HAVE_HSEARCH_R=yes])
 AM_CONDITIONAL(ALSA_HSEARCH_R, [test "x$HAVE_HSEARCH_R" != xyes])
+AC_CHECK_FUNCS([uselocale])
 
 SAVE_LIBRARY_VERSION
 AC_SUBST(LIBTOOL_VERSION_INFO)
-- 
1.7.0.4

[PATCH alsa-lib 2/2] Use thread-safe locale functions if available

[Rémi Denis-Courmont]

setlocale() is not thread-safe. It can actually trigger a crash if
another thread uses locale informations at the same time in the process.
Library code should use POSIX newlocale/duplocale/uselocale/freelocale
instead. Those functions only change the locale data for the calling
thread.
---
 src/conf.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/src/conf.c b/src/conf.c
index 570c90f..5d8c5c9 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -499,22 +499,38 @@ static int safe_strtod(const char *str, double *val)
 {
 	char *end;
 	double v;
+#ifdef HAVE_USELOCALE
+	locale_t saved_locale, c_locale;
+#else
 	char *saved_locale;
 	char locstr[64]; /* enough? */
+#endif
 	int err;
 
 	if (!*str)
 		return -EINVAL;
+#ifdef HAVE_USELOCALE
+	c_locale = newlocale(LC_NUMERIC_MASK, "C", 0);
+	saved_locale = uselocale(c_locale);
+#else
 	saved_locale = setlocale(LC_NUMERIC, NULL);
 	if (saved_locale) {
 		snprintf(locstr, sizeof(locstr), "%s", saved_locale);
 		setlocale(LC_NUMERIC, "C");
 	}
+#endif
 	errno = 0;
 	v = strtod(str, &end);
 	err = -errno;
+#ifdef HAVE_USELOCALE
+	if (c_locale != (locale_t)0) {
+		uselocale(saved_locale);
+		freelocale(c_locale);
+	}
+#else
 	if (saved_locale)
 		setlocale(LC_NUMERIC, locstr);
+#endif
 	if (err)
 		return err;
 	if (*end)
-- 
1.7.0.4

Re: [PATCH alsa-lib 2/2] Use thread-safe locale functions if available

[Jaroslav Kysela]

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On Wed, 21 Apr 2010, Rémi Denis-Courmont wrote:

> setlocale() is not thread-safe. It can actually trigger a crash if
> another thread uses locale informations at the same time in the process.
> Library code should use POSIX newlocale/duplocale/uselocale/freelocale
> instead. Those functions only change the locale data for the calling
> thread.

Thanks. I applied both patches to alsa-lib git repo.

 					Jaroslav

-----
Jaroslav Kysela <perex@perex.cz>
Linux Kernel Sound Maintainer
ALSA Project, Red Hat, Inc.

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