[PATCH v37 5/9] win32u: Open the global session shared mapping.

[Rémi Bernon]

From: Rémi Bernon

---
 dlls/win32u/winstation.c | 103 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 101 insertions(+), 2 deletions(-)

diff --git a/dlls/win32u/winstation.c b/dlls/win32u/winstation.c
index 3e71218200a..d094e212d55 100644
--- a/dlls/win32u/winstation.c
+++ b/dlls/win32u/winstation.c
@@ -22,9 +22,14 @@
 #pragma makedep unix
 #endif

+#include <assert.h>
+#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 +45,96 @@ WINE_DECLARE_DEBUG_CHANNEL(win);

#define DESKTOP_ALL_ACCESS 0x01ff

+struct session_block
+{
+    struct list entry;      /* entry in the session block list */
+    const char *data;       /* base pointer for the mmaped data */
+    SIZE_T      offset;     /* offset of data in the session shared mapping */
+    SIZE_T      size;       /* size of the mmaped data */
+};
+
+static pthread_mutex_t session_lock = PTHREAD_MUTEX_INITIALIZER;
+static struct list session_blocks = LIST_INIT(session_blocks);
+
+static NTSTATUS map_shared_session_block( SIZE_T offset, SIZE_T size, struct session_block **ret )
+{
+    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 );
+    LARGE_INTEGER off = {.QuadPart = offset & ~(PAGE_SIZE - 1)};
+    struct session_block *block;
+    OBJECT_ATTRIBUTES attr;
+    unsigned int status;
+    HANDLE handle;
+
+    assert( offset + size > offset );
+
+    if (!(block = calloc( 1, sizeof(*block) ))) return STATUS_NO_MEMORY;
+
+    InitializeObjectAttributes( &attr, &name, 0, NULL, NULL );
+    if (!(status = NtOpenSection( &handle, SECTION_MAP_READ, &attr )))
+    {
+        if (!(status = NtMapViewOfSection( handle, GetCurrentProcess(), (void **)&block->data, 0, 0,
+                                           &off, &block->size, ViewUnmap, 0, PAGE_READONLY )))
+        {
+            list_add_tail( &session_blocks, &block->entry );
+            block->offset = off.QuadPart;
+            assert( block->offset + block->size > block->offset );
+        }
+        NtClose( handle );
+    }
+
+    if (status) free( block );
+    else *ret = block;
+    return status;
+}
+
+static NTSTATUS find_shared_session_block( SIZE_T offset, SIZE_T size, struct session_block **ret )
+{
+    struct session_block *block;
+    UINT status;
+
+    assert( offset + size > offset );
+
+    pthread_mutex_lock( &session_lock );
+
+    LIST_FOR_EACH_ENTRY( block, &session_blocks, struct session_block, entry )
+    {
+        if (block->offset < offset && offset + size <= block->offset + block->size)
+        {
+            *ret = block;
+            pthread_mutex_unlock( &session_lock );
+            return STATUS_SUCCESS;
+        }
+    }
+
+    status = map_shared_session_block( offset, size, ret );
+
+    pthread_mutex_unlock( &session_lock );
+
+    return status;
+}
+
+static NTSTATUS set_shared_object_cache( obj_locator_t locator, const shared_object_t **object_cache, UINT64 *id )
+{
+    const shared_object_t *object = NULL;
+    struct session_block *block;
+    NTSTATUS status;
+
+    if (!locator.id) status = STATUS_INVALID_HANDLE;
+    else if (!(status = find_shared_session_block( locator.offset, sizeof(*object), &block )))
+    {
+        object = (const shared_object_t *)(block->data + locator.offset - block->offset);
+        *id = locator.id; /* return the expected id separately from the object itself */
+    }
+
+    *object_cache = object;
+    return status;
+}
+
 BOOL is_virtual_desktop(void)
 {
     HANDLE desktop = NtUserGetThreadDesktop( GetCurrentThreadId() );
@@ -249,11 +344,12 @@ HDESK WINAPI NtUserGetThreadDesktop( DWORD thread )
 BOOL WINAPI NtUserSetThreadDesktop( HDESK handle )
 {
     BOOL ret, was_virtual_desktop = is_virtual_desktop();
+    obj_locator_t locator = {0};

SERVER_START_REQ( set_thread_desktop )
     {
         req->handle = wine_server_obj_handle( handle );
-        ret = !wine_server_call_err( req );
+        if ((ret = !wine_server_call_err( req ))) locator = reply->locator;
     }
     SERVER_END_REQ;

@@ -261,6 +357,9 @@ BOOL WINAPI NtUserSetThreadDesktop( HDESK handle )
     {
         struct user_thread_info *thread_info = get_user_thread_info();
         struct user_key_state_info *key_state_info = thread_info->key_state;
+        const shared_object_t *cache;
+        UINT64 id;
+        set_shared_object_cache( locator, &cache, &id );
         thread_info->client_info.top_window = 0;
         thread_info->client_info.msg_window = 0;
         if (key_state_info) key_state_info->time = 0;