Re: Fix libunistring in MS-Windows locales

[Daiki Ueno]

Eli Zaretskii <address@hidden> writes:

>> > Actually, I see that libunistring already includes functions for
>> > locking (which on Windows wrap the 2 APIs I mentioned above).  So I
>> > guess it's best to use them.
>> 
>> Yes, could you create a patch in that direction?
>
> Will do.

Here is a simple patch for this.  Is it OK for you?

>From a9576350604e97fc3c3fa16778e6e3d10094f97a Mon Sep 17 00:00:00 2001
From: Daiki Ueno <address@hidden>
Date: Thu, 7 Aug 2014 08:46:52 +0900
Subject: [PATCH] localename: make gl_locale_name_thread really thread-safe on
 Windows

* lib/localename.c [WINDOWS_NATIVE && !IN_LIBINTL]: Include
"glthread/lock.h".
(get_lcid_lock) [WINDOWS_NATIVE]: New variable.
(get_lcid) [WINDOWS_NATIVE]: Lock while looking for an LCID.
---
 ChangeLog        |  8 ++++++++
 lib/localename.c | 15 ++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 8e74a54..99b0dec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2014-08-07  Daiki Ueno  <address@hidden>
+
+       localename: make gl_locale_name_thread really thread-safe on Windows
+       * lib/localename.c [WINDOWS_NATIVE && !IN_LIBINTL]: Include
+       "glthread/lock.h".
+       (get_lcid_lock) [WINDOWS_NATIVE]: New variable.
+       (get_lcid) [WINDOWS_NATIVE]: Lock while looking for an LCID.
+
 2014-08-05  Paul Eggert  <address@hidden>
 
        sys_select: fix FD_ZERO problem on Solaris 10
diff --git a/lib/localename.c b/lib/localename.c
index 4cce060..78dc344 100644
--- a/lib/localename.c
+++ b/lib/localename.c
@@ -55,6 +55,9 @@
 
 #if defined _WIN32 || defined __WIN32__
 # define WINDOWS_NATIVE
+# if !defined IN_LIBINTL
+#  include "glthread/lock.h"
+# endif
 #endif
 
 #if defined WINDOWS_NATIVE || defined __CYGWIN__ /* Native Windows or Cygwin */
@@ -2542,6 +2545,9 @@ enum_locales_fn (LPTSTR locale_num_str)
   return TRUE;
 }
 
+/* This lock protects the get_lcid against multiple simultaneous calls.  */
+gl_lock_define_initialized(static, get_lcid_lock)
+
 /* Return the Locale ID (LCID) number given the locale's name, a
    string, in LOCALE_NAME.  This works by enumerating all the locales
    supported by the system, until we find one whose name matches
@@ -2553,8 +2559,14 @@ get_lcid (const char *locale_name)
   static LCID last_lcid;
   static char last_locale[1000];
 
+  /* Lock while looking for an LCID, to protect access to static
+     variables: last_lcid, last_locale, found_lcid, and lname.  */
+  gl_lock_lock (get_lcid_lock);
   if (last_lcid > 0 && strcmp (locale_name, last_locale) == 0)
-    return last_lcid;
+    {
+      gl_lock_unlock (get_lcid_lock);
+      return last_lcid;
+    }
   strncpy (lname, locale_name, sizeof (lname) - 1);
   lname[sizeof (lname) - 1] = '\0';
   found_lcid = 0;
@@ -2564,6 +2576,7 @@ get_lcid (const char *locale_name)
       last_lcid = found_lcid;
       strcpy (last_locale, locale_name);
     }
+  gl_lock_unlock (get_lcid_lock);
   return found_lcid;
 }
 
-- 
1.9.3

Regards,
--
Daiki Ueno