From d5b2c3f233d2a7263f3b79133ce6216fa991c1f2 Mon Sep 17 00:00:00 2001
From: Piotr Caban <piotr@codeweavers.com>
Date: Wed, 25 Nov 2020 20:24:30 +0100
Subject: [PATCH] msvcrt: Lock _MB_CP_LOCK lock in setmbcp.

Signed-off-by: Piotr Caban <piotr@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>
---
 dlls/msvcrt/locale.c | 12 ++++--------
 dlls/msvcrt/mbcs.c   | 28 ++++++++++++++++++----------
 dlls/msvcrt/msvcrt.h |  1 -
 3 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/dlls/msvcrt/locale.c b/dlls/msvcrt/locale.c
index 2a66867928c..82a499c5637 100644
--- a/dlls/msvcrt/locale.c
+++ b/dlls/msvcrt/locale.c
@@ -599,18 +599,14 @@ MSVCRT_pthreadlocinfo CDECL get_locinfo(void) {
     return *get_locinfo_ptr();
 }
 
-MSVCRT_pthreadmbcinfo* CDECL get_mbcinfo_ptr(void) {
+/* INTERNAL: returns pthreadmbcinfo struct */
+MSVCRT_pthreadmbcinfo CDECL get_mbcinfo(void) {
     thread_data_t *data = msvcrt_get_thread_data();
 
     if(!data || !(data->locale_flags & LOCALE_THREAD))
-        return &MSVCRT_locale->mbcinfo;
+        return MSVCRT_locale->mbcinfo;
 
-    return &data->mbcinfo;
-}
-
-/* INTERNAL: returns pthreadmbcinfo struct */
-MSVCRT_pthreadmbcinfo CDECL get_mbcinfo(void) {
-    return *get_mbcinfo_ptr();
+    return data->mbcinfo;
 }
 
 /* INTERNAL: constructs string returned by setlocale */
diff --git a/dlls/msvcrt/mbcs.c b/dlls/msvcrt/mbcs.c
index a920dcea5f1..d4434209a43 100644
--- a/dlls/msvcrt/mbcs.c
+++ b/dlls/msvcrt/mbcs.c
@@ -28,6 +28,7 @@
 #include <mbctype.h>
 
 #include "msvcrt.h"
+#include "mtdll.h"
 #include "winnls.h"
 #include "wine/debug.h"
 
@@ -209,9 +210,6 @@ int CDECL ___mb_cur_max_l_func(MSVCRT__locale_t locale)
 }
 #endif
 
-/*********************************************************************
- * INTERNAL: _setmbcp_l
- */
 MSVCRT_threadmbcinfo* create_mbcinfo(int cp, LCID lcid, MSVCRT_threadmbcinfo *old_mbcinfo)
 {
   MSVCRT_threadmbcinfo *mbcinfo;
@@ -386,20 +384,30 @@ MSVCRT_threadmbcinfo* create_mbcinfo(int cp, LCID lcid, MSVCRT_threadmbcinfo *ol
  */
 int CDECL _setmbcp(int cp)
 {
-    MSVCRT_threadmbcinfo **old_mbcinfo = get_mbcinfo_ptr();
+    thread_data_t *data = msvcrt_get_thread_data();
     MSVCRT_threadmbcinfo *mbcinfo;
 
-    mbcinfo = create_mbcinfo(cp, -1, *old_mbcinfo);
-    if(!mbcinfo) {
+    mbcinfo = create_mbcinfo(cp, -1, get_mbcinfo());
+    if(!mbcinfo)
+    {
         *MSVCRT__errno() = MSVCRT_EINVAL;
         return -1;
     }
 
-    free_mbcinfo(*old_mbcinfo);
-    *old_mbcinfo = mbcinfo;
-
-    if(mbcinfo == MSVCRT_locale->mbcinfo)
+    if(data->locale_flags & LOCALE_THREAD)
+    {
+        if(data->locale_flags & LOCALE_FREE)
+            free_mbcinfo(data->mbcinfo);
+        data->mbcinfo = mbcinfo;
+    }
+    else
+    {
+        _lock(_MB_CP_LOCK);
+        free_mbcinfo(MSVCRT_locale->mbcinfo);
+        MSVCRT_locale->mbcinfo = mbcinfo;
         memcpy(MSVCRT_mbctype, MSVCRT_locale->mbcinfo->mbctype, sizeof(MSVCRT_mbctype));
+        _unlock(_MB_CP_LOCK);
+    }
     return 0;
 }
 
diff --git a/dlls/msvcrt/msvcrt.h b/dlls/msvcrt/msvcrt.h
index 5881ecc5d04..52aafcff869 100644
--- a/dlls/msvcrt/msvcrt.h
+++ b/dlls/msvcrt/msvcrt.h
@@ -1008,7 +1008,6 @@ MSVCRT__locale_t CDECL get_current_locale_noalloc(MSVCRT__locale_t locale) DECLS
 void CDECL free_locale_noalloc(MSVCRT__locale_t locale) DECLSPEC_HIDDEN;
 MSVCRT_pthreadlocinfo CDECL get_locinfo(void) DECLSPEC_HIDDEN;
 MSVCRT_pthreadmbcinfo CDECL get_mbcinfo(void) DECLSPEC_HIDDEN;
-MSVCRT_pthreadmbcinfo* CDECL get_mbcinfo_ptr(void) DECLSPEC_HIDDEN;
 void __cdecl MSVCRT__free_locale(MSVCRT__locale_t);
 MSVCRT_threadmbcinfo* create_mbcinfo(int, LCID, MSVCRT_threadmbcinfo*) DECLSPEC_HIDDEN;
 void free_locinfo(MSVCRT_pthreadlocinfo) DECLSPEC_HIDDEN;