[PATCH v19 2/8] win32u: Open the global session shared mapping.

[Rémi Bernon]

From: Rémi Bernon

---
 dlls/win32u/winstation.c | 86 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 85 insertions(+), 1 deletion(-)

diff --git a/dlls/win32u/winstation.c b/dlls/win32u/winstation.c
index b187b246941..7537ce944d5 100644
--- a/dlls/win32u/winstation.c
+++ b/dlls/win32u/winstation.c
@@ -22,9 +22,12 @@
 #pragma makedep unix
 #endif

+#include <stdarg.h>
+#include <stddef.h>
+#include <pthread.h>
+
 #include "ntstatus.h"
 #define WIN32_NO_STATUS
-#include <stdarg.h>
 #include "windef.h"
 #include "winbase.h"
 #include "ntuser.h"
@@ -40,6 +43,85 @@ WINE_DECLARE_DEBUG_CHANNEL(win);

#define DESKTOP_ALL_ACCESS 0x01ff

+static pthread_mutex_t session_lock = PTHREAD_MUTEX_INITIALIZER;
+static struct shared_session *shared_session;
+
+struct shared_session
+{
+    LONG ref;
+    const session_shm_t *shared;
+};
+
+static struct shared_session *shared_session_acquire( struct shared_session *session )
+{
+    InterlockedIncrement( &session->ref );
+    return session;
+}
+
+static void shared_session_release( struct shared_session *session )
+{
+    if (!InterlockedDecrement( &session->ref ))
+    {
+        NtUnmapViewOfSection( GetCurrentProcess(), (void *)session->shared );
+        free( session );
+    }
+}
+
+static struct shared_session *get_shared_session( BOOL force )
+{
+    struct shared_session *session;
+
+    pthread_mutex_lock( &session_lock );
+
+    if (!shared_session) force = TRUE;
+    if (force && (session = calloc( 1, sizeof(*session) )))
+    {
+        static const WCHAR nameW[] =
+        {
+            '\','K','e','r','n','e','l','O','b','j','e','c','t','s','\',
+            '_','_','w','i','n','e','_','s','e','s','s','i','o','n',0
+        };
+        UNICODE_STRING name = RTL_CONSTANT_STRING( nameW );
+        OBJECT_ATTRIBUTES attr;
+        unsigned int status;
+        HANDLE handle;
+
+        session->ref = 1;
+
+        InitializeObjectAttributes( &attr, &name, 0, NULL, NULL );
+        if (!(status = NtOpenSection( &handle, SECTION_MAP_READ | SECTION_QUERY, &attr )))
+        {
+            SECTION_BASIC_INFORMATION info;
+
+            if (!(status = NtQuerySection( handle, SectionBasicInformation, &info, sizeof(info), NULL )))
+            {
+                SIZE_T size = info.Size.QuadPart;
+                status = NtMapViewOfSection( handle, GetCurrentProcess(), (void **)&session->shared,
+                                             0, 0, NULL, &size, ViewUnmap, 0, PAGE_READONLY );
+            }
+
+            NtClose( handle );
+        }
+
+        if (status)
+        {
+            ERR( "Failed to map session mapping, status %#x\n", status );
+            free( session );
+        }
+        else
+        {
+            if (shared_session) shared_session_release( shared_session );
+            shared_session = session;
+        }
+    }
+
+    session = shared_session_acquire( shared_session );
+
+    pthread_mutex_unlock( &session_lock );
+
+    return session;
+}
+
 BOOL is_virtual_desktop(void)
 {
     HANDLE desktop = NtUserGetThreadDesktop( GetCurrentThreadId() );
@@ -622,6 +704,8 @@ void winstation_init(void)

static const WCHAR winsta0[] = {'W','i','n','S','t','a','0',0};

+    shared_session = get_shared_session( FALSE );
+
     if (params->Desktop.Length)
     {
         buffer = malloc( params->Desktop.Length + sizeof(WCHAR) );