[PATCH v16 0/5] MR3103: server: Create and use a desktop shared mapping for GetCursorPos.

[Rémi Bernon (＠rbernon)]

First part of Proton shared memory series. The full branch can be seen at https://gitlab.winehq.org/rbernon/wine/-/commits/mr/shared-memories.

--
  v16: user32: Use the desktop shared data for GetCursorPos().
       server: Expose the desktop shared mapping to clients.
       server: Add a sequence number to the shared data.
       server: Move the cursor position and last change time to the shared data.
       server: Create a desktop shared mapping.

https://gitlab.winehq.org/wine/wine/-/merge_requests/3103

[PATCH v16 1/5] server: Create a desktop shared mapping.

[Rémi Bernon]

From: Rémi Bernon

Based on a patch by Huw Davies .
---
 server/file.h       |  1 +
 server/mapping.c    | 17 +++++++++++++++++
 server/protocol.def |  6 ++++++
 server/user.h       |  2 ++
 server/winstation.c | 12 ++++++++++++
 5 files changed, 38 insertions(+)

diff --git a/server/file.h b/server/file.h
index 7f2d1637863..e953120ef80 100644
--- a/server/file.h
+++ b/server/file.h
@@ -188,6 +188,7 @@ extern struct mapping *create_fd_mapping( struct object *root, const struct unic
                                           unsigned int attr, const struct security_descriptor *sd );
 extern struct object *create_user_data_mapping( struct object *root, const struct unicode_str *name,
                                                 unsigned int attr, const struct security_descriptor *sd );
+extern struct object *create_object_mapping( struct object *object, mem_size_t size, void **ptr );

/* device functions */

diff --git a/server/mapping.c b/server/mapping.c
index 6b0de1b8b94..90b9c3bbe57 100644
--- a/server/mapping.c
+++ b/server/mapping.c
@@ -1256,6 +1256,23 @@ int get_page_size(void)
     return page_mask + 1;
 }

+struct object *create_object_mapping( struct object *object, mem_size_t size, void **ptr )
+{
+    static const unsigned int access = FILE_READ_DATA | FILE_WRITE_DATA;
+    struct mapping *mapping;
+    void *tmp;
+
+    if (!(mapping = create_mapping( object, NULL, 0, size, SEC_COMMIT, 0, access, NULL ))) return NULL;
+    if ((tmp = mmap( NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, get_unix_fd( mapping->fd ), 0 )) == MAP_FAILED)
+    {
+        release_object( &mapping->obj );
+        return NULL;
+    }
+
+    *ptr = tmp;
+    return &mapping->obj;
+}
+
 struct object *create_user_data_mapping( struct object *root, const struct unicode_str *name,
                                         unsigned int attr, const struct security_descriptor *sd )
 {
diff --git a/server/protocol.def b/server/protocol.def
index 8b51618ebe0..531dace749e 100644
--- a/server/protocol.def
+++ b/server/protocol.def
@@ -879,6 +879,12 @@ typedef struct
     lparam_t info;
 } cursor_pos_t;

+struct desktop_shared_memory
+{
+    int placeholder;
+};
+typedef volatile struct desktop_shared_memory desktop_shm_t;
+
 /****************************************************************/
 /* Request declarations */

diff --git a/server/user.h b/server/user.h
index 8fa55e09b0f..446e06ebb0c 100644
--- a/server/user.h
+++ b/server/user.h
@@ -76,6 +76,8 @@ struct desktop
     unsigned int         users;            /* processes and threads using this desktop */
     struct global_cursor cursor;           /* global cursor information */
     unsigned char        keystate[256];    /* asynchronous key state */
+    struct object       *shared_mapping;   /* desktop shared memory mapping */
+    const desktop_shm_t *shared;           /* desktop shared memory */
 };

/* user handles functions */
diff --git a/server/winstation.c b/server/winstation.c
index 5903497d61e..cedda7d5470 100644
--- a/server/winstation.c
+++ b/server/winstation.c
@@ -23,6 +23,7 @@
 #include <stdio.h>
 #include <stdarg.h>
 #include <sys/types.h>
+#include <sys/mman.h>

#include "ntstatus.h"
 #define WIN32_NO_STATUS
@@ -240,6 +241,15 @@ static struct desktop *create_desktop( const struct unicode_str *name, unsigned
             memset( desktop->keystate, 0, sizeof(desktop->keystate) );
             list_add_tail( &winstation->desktops, &desktop->entry );
             list_init( &desktop->hotkeys );
+            desktop->shared_mapping = NULL;
+            desktop->shared = NULL;
+
+            if (!(desktop->shared_mapping = create_object_mapping( &desktop->obj, sizeof(*desktop->shared),
+                                                                   (void **)&desktop->shared )))
+            {
+                release_object( desktop );
+                return NULL;
+            }
         }
         else
         {
@@ -298,6 +308,8 @@ static void desktop_destroy( struct object *obj )
     if (desktop->close_timeout) remove_timeout_user( desktop->close_timeout );
     list_remove( &desktop->entry );
     release_object( desktop->winstation );
+    if (desktop->shared_mapping) release_object( desktop->shared_mapping );
+    if (desktop->shared) munmap( (void *)desktop->shared, sizeof(*desktop->shared) );
 }

/* retrieve the thread desktop, checking the handle access rights */

[PATCH v16 2/5] server: Move the cursor position and last change time to the shared data.

[Rémi Bernon]

From: Rémi Bernon

Based on a patch by Huw Davies .
---
 server/protocol.def |  9 ++++-
 server/queue.c      | 90 ++++++++++++++++++++++++++++-----------------
 server/user.h       |  3 --
 3 files changed, 65 insertions(+), 37 deletions(-)

diff --git a/server/protocol.def b/server/protocol.def
index 531dace749e..7c39a1ba0b0 100644
--- a/server/protocol.def
+++ b/server/protocol.def
@@ -879,9 +879,16 @@ typedef struct
     lparam_t info;
 } cursor_pos_t;

+struct shared_cursor
+{
+    int                  x;                /* cursor position */
+    int                  y;
+    unsigned int         last_change;      /* time of last position change */
+};
+
 struct desktop_shared_memory
 {
-    int placeholder;
+    struct shared_cursor cursor;           /* global cursor information */
 };
 typedef volatile struct desktop_shared_memory desktop_shm_t;

diff --git a/server/queue.c b/server/queue.c
index 6f38227aa84..f822826a8dd 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -233,6 +233,16 @@ static unsigned int last_input_time;
 static cursor_pos_t cursor_history[64];
 static unsigned int cursor_history_latest;

+#define SHARED_WRITE_BEGIN( object, type )                        \
+    do {                                                          \
+        const type *__shared = (object)->shared;                  \
+        type *shared = (type *)__shared;                          \
+        do
+
+#define SHARED_WRITE_END                                          \
+        while(0);                                                 \
+    } while(0)
+
 static void queue_hardware_message( struct desktop *desktop, struct message *msg, int always_queue );
 static void free_message( struct message *msg );

@@ -424,8 +434,8 @@ static void queue_cursor_message( struct desktop *desktop, user_handle_t win, un
     msg->msg = message;
     msg->wparam = wparam;
     msg->lparam = lparam;
-    msg->x = desktop->cursor.x;
-    msg->y = desktop->cursor.y;
+    msg->x = desktop->shared->cursor.x;
+    msg->y = desktop->shared->cursor.y;
     if (!(msg->win = win) && (input = desktop->foreground_input)) msg->win = input->active;
     queue_hardware_message( desktop, msg, 1 );
 }
@@ -464,13 +474,19 @@ static int update_desktop_cursor_window( struct desktop *desktop, user_handle_t
 static int update_desktop_cursor_pos( struct desktop *desktop, user_handle_t win, int x, int y )
 {
     int updated;
+    unsigned int time = get_tick_count();

x = max( min( x, desktop->cursor.clip.right - 1 ), desktop->cursor.clip.left );
     y = max( min( y, desktop->cursor.clip.bottom - 1 ), desktop->cursor.clip.top );
-    updated = (desktop->cursor.x != x || desktop->cursor.y != y);
-    desktop->cursor.x = x;
-    desktop->cursor.y = y;
-    desktop->cursor.last_change = get_tick_count();
+
+    SHARED_WRITE_BEGIN( desktop, desktop_shm_t )
+    {
+        updated = shared->cursor.x != x || shared->cursor.y != y;
+        shared->cursor.x = x;
+        shared->cursor.y = y;
+        shared->cursor.last_change = time;
+    }
+    SHARED_WRITE_END;

if (!win || !is_window_visible( win ) || is_window_transparent( win ))
         win = shallow_window_from_point( desktop, x, y );
@@ -516,8 +532,8 @@ static void get_message_defaults( struct msg_queue *queue, int *x, int *y, unsig
 {
     struct desktop *desktop = queue->input->desktop;

-    *x = desktop->cursor.x;
-    *y = desktop->cursor.y;
+    *x = desktop->shared->cursor.x;
+    *y = desktop->shared->cursor.y;
     *time = get_tick_count();
 }

@@ -541,9 +557,9 @@ void set_clip_rectangle( struct desktop *desktop, const rectangle_t *rect, unsig
     else desktop->cursor.clip = top_rect;

/* warp the mouse to be inside the clip rect */
-    x = max( min( desktop->cursor.x, desktop->cursor.clip.right - 1 ), desktop->cursor.clip.left );
-    y = max( min( desktop->cursor.y, desktop->cursor.clip.bottom - 1 ), desktop->cursor.clip.top );
-    if (x != desktop->cursor.x || y != desktop->cursor.y) set_cursor_pos( desktop, x, y );
+    x = max( min( desktop->shared->cursor.x, desktop->cursor.clip.right - 1 ), desktop->cursor.clip.left );
+    y = max( min( desktop->shared->cursor.y, desktop->cursor.clip.bottom - 1 ), desktop->cursor.clip.top );
+    if (x != desktop->shared->cursor.x || y != desktop->shared->cursor.y) set_cursor_pos( desktop, x, y );

/* request clip cursor rectangle reset to the desktop thread */
     if (reset) post_desktop_message( desktop, WM_WINE_CLIPCURSOR, flags, FALSE );
@@ -1696,8 +1712,8 @@ static void queue_hardware_message( struct desktop *desktop, struct message *msg
         if (desktop->keystate[VK_XBUTTON2] & 0x80) msg->wparam |= MK_XBUTTON2;
         break;
     }
-    msg->x = desktop->cursor.x;
-    msg->y = desktop->cursor.y;
+    msg->x = desktop->shared->cursor.x;
+    msg->y = desktop->shared->cursor.y;

if (msg->win && (thread = get_window_thread( msg->win )))
     {
@@ -1996,7 +2012,7 @@ static int queue_mouse_message( struct desktop *desktop, user_handle_t win, cons
     struct rawinput_message raw_msg;
     struct message *msg;
     struct thread *foreground;
-    unsigned int i, time, flags;
+    unsigned int i, time = get_tick_count(), flags;
     struct hw_msg_source source = { IMDT_MOUSE, origin };
     int wait = 0, x, y;

@@ -2017,10 +2033,15 @@ static int queue_mouse_message( struct desktop *desktop, user_handle_t win, cons
         WM_MOUSEHWHEEL   /* 0x1000 = MOUSEEVENTF_HWHEEL */
     };

-    desktop->cursor.last_change = get_tick_count();
+    SHARED_WRITE_BEGIN( desktop, desktop_shm_t )
+    {
+        shared->cursor.last_change = time;
+    }
+    SHARED_WRITE_END;
+
     flags = input->mouse.flags;
     time  = input->mouse.time;
-    if (!time) time = desktop->cursor.last_change;
+    if (!time) time = desktop->shared->cursor.last_change;

if (flags & MOUSEEVENTF_MOVE)
     {
@@ -2029,23 +2050,26 @@ static int queue_mouse_message( struct desktop *desktop, user_handle_t win, cons
             x = input->mouse.x;
             y = input->mouse.y;
             if (flags & ~(MOUSEEVENTF_MOVE | MOUSEEVENTF_ABSOLUTE) &&
-                x == desktop->cursor.x && y == desktop->cursor.y)
+                x == desktop->shared->cursor.x && y == desktop->shared->cursor.y)
                 flags &= ~MOUSEEVENTF_MOVE;
         }
         else
         {
-            x = desktop->cursor.x + input->mouse.x;
-            y = desktop->cursor.y + input->mouse.y;
+            x = desktop->shared->cursor.x + input->mouse.x;
+            y = desktop->shared->cursor.y + input->mouse.y;
         }
     }
     else
     {
-        x = desktop->cursor.x;
-        y = desktop->cursor.y;
+        x = desktop->shared->cursor.x;
+        y = desktop->shared->cursor.y;
     }

if ((foreground = get_foreground_thread( desktop, win )))
     {
+        int raw_x, raw_y;
+        raw_x = x - desktop->shared->cursor.x;
+        raw_y = y - desktop->shared->cursor.y;
         memset( &raw_msg, 0, sizeof(raw_msg) );
         raw_msg.foreground = foreground;
         raw_msg.desktop    = desktop;
@@ -2053,7 +2077,7 @@ static int queue_mouse_message( struct desktop *desktop, user_handle_t win, cons
         raw_msg.time       = time;
         raw_msg.message    = WM_INPUT;
         raw_msg.flags      = flags;
-        rawmouse_init( &raw_msg.rawinput, &raw_msg.data.mouse, x - desktop->cursor.x, y - desktop->cursor.y,
+        rawmouse_init( &raw_msg.rawinput, &raw_msg.data.mouse, raw_x, raw_y,
                        raw_msg.flags, input->mouse.data, input->mouse.info );

enum_processes( queue_rawinput_message, &raw_msg );
@@ -2263,8 +2287,8 @@ static void queue_custom_hardware_message( struct desktop *desktop, user_handle_
     msg->msg       = input->hw.msg;
     msg->wparam    = 0;
     msg->lparam    = input->hw.lparam;
-    msg->x         = desktop->cursor.x;
-    msg->y         = desktop->cursor.y;
+    msg->x         = desktop->shared->cursor.x;
+    msg->y         = desktop->shared->cursor.y;

queue_hardware_message( desktop, msg, 1 );
 }
@@ -2785,8 +2809,8 @@ DECL_HANDLER(send_hardware_message)
         }
     }

-    reply->prev_x = desktop->cursor.x;
-    reply->prev_y = desktop->cursor.y;
+    reply->prev_x = desktop->shared->cursor.x;
+    reply->prev_y = desktop->shared->cursor.y;

switch (req->input.type)
     {
@@ -2804,8 +2828,8 @@ DECL_HANDLER(send_hardware_message)
     }
     if (thread) release_object( thread );

-    reply->new_x = desktop->cursor.x;
-    reply->new_y = desktop->cursor.y;
+    reply->new_x = desktop->shared->cursor.x;
+    reply->new_y = desktop->shared->cursor.y;
     release_object( desktop );
 }

@@ -3497,8 +3521,8 @@ DECL_HANDLER(set_cursor)

reply->prev_handle = input->cursor;
     reply->prev_count  = input->cursor_count;
-    reply->prev_x      = desktop->cursor.x;
-    reply->prev_y      = desktop->cursor.y;
+    reply->prev_x      = desktop->shared->cursor.x;
+    reply->prev_y      = desktop->shared->cursor.y;

if (req->flags & SET_CURSOR_HANDLE)
     {
@@ -3521,10 +3545,10 @@ DECL_HANDLER(set_cursor)
     if (req->flags & (SET_CURSOR_HANDLE | SET_CURSOR_COUNT))
         update_desktop_cursor_handle( desktop, input );

-    reply->new_x       = desktop->cursor.x;
-    reply->new_y       = desktop->cursor.y;
+    reply->new_x       = desktop->shared->cursor.x;
+    reply->new_y       = desktop->shared->cursor.y;
     reply->new_clip    = desktop->cursor.clip;
-    reply->last_change = desktop->cursor.last_change;
+    reply->last_change = desktop->shared->cursor.last_change;
 }

/* Get the history of the 64 last cursor positions */
diff --git a/server/user.h b/server/user.h
index 446e06ebb0c..6a0e3d65ab7 100644
--- a/server/user.h
+++ b/server/user.h
@@ -54,10 +54,7 @@ struct winstation

struct global_cursor
 {
-    int                  x;                /* cursor position */
-    int                  y;
     rectangle_t          clip;             /* cursor clip rectangle */
-    unsigned int         last_change;      /* time of last position change */
     user_handle_t        win;              /* window that contains the cursor */
 };

[PATCH v16 3/5] server: Add a sequence number to the shared data.

[Rémi Bernon]

From: Rémi Bernon

Based on a patch by Huw Davies .
---
 server/protocol.def |  1 +
 server/queue.c      | 22 ++++++++++++++++------
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/server/protocol.def b/server/protocol.def
index 7c39a1ba0b0..88666a8ca41 100644
--- a/server/protocol.def
+++ b/server/protocol.def
@@ -888,6 +888,7 @@ struct shared_cursor

struct desktop_shared_memory
 {
+    unsigned int         seq;              /* sequence number - server updating if (seq & 1) != 0 */
     struct shared_cursor cursor;           /* global cursor information */
 };
 typedef volatile struct desktop_shared_memory desktop_shm_t;
diff --git a/server/queue.c b/server/queue.c
index f822826a8dd..8067e1b0f31 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -233,14 +233,24 @@ static unsigned int last_input_time;
 static cursor_pos_t cursor_history[64];
 static unsigned int cursor_history_latest;

-#define SHARED_WRITE_BEGIN( object, type )                        \
-    do {                                                          \
-        const type *__shared = (object)->shared;                  \
-        type *shared = (type *)__shared;                          \
+#if defined(__i386__) || defined(__x86_64__)
+#define __SHARED_INCREMENT_SEQ( x ) ++(x)
+#else
+#define __SHARED_INCREMENT_SEQ( x ) __atomic_add_fetch( &(x), 1, __ATOMIC_RELEASE )
+#endif
+
+#define SHARED_WRITE_BEGIN( object, type )                           \
+    do {                                                             \
+        const type *__shared = (object)->shared;                     \
+        type *shared = (type *)__shared;                             \
+        unsigned int __seq = __SHARED_INCREMENT_SEQ( shared->seq );  \
+        assert( (__seq & 1) != 0 );                                  \
         do

-#define SHARED_WRITE_END                                          \
-        while(0);                                                 \
+#define SHARED_WRITE_END                                             \
+        while(0);                                                    \
+        __seq = __SHARED_INCREMENT_SEQ( shared->seq ) - __seq;       \
+        assert( __seq == 1 );                                        \
     } while(0)

static void queue_hardware_message( struct desktop *desktop, struct message *msg, int always_queue );

[PATCH v16 4/5] server: Expose the desktop shared mapping to clients.

[Rémi Bernon]

From: Rémi Bernon

Through a generic object mapping mechanism using __wine_mapping name.
---
 server/async.c      |  2 ++
 server/atom.c       |  1 +
 server/change.c     |  1 +
 server/clipboard.c  |  1 +
 server/completion.c |  1 +
 server/console.c    |  7 +++++++
 server/debugger.c   |  2 ++
 server/device.c     |  9 +++++++++
 server/directory.c  |  2 ++
 server/event.c      |  2 ++
 server/fd.c         |  4 ++++
 server/file.c       |  1 +
 server/handle.c     |  1 +
 server/hook.c       |  1 +
 server/mailslot.c   |  4 ++++
 server/mapping.c    | 28 ++++++++++++++++++++++++++++
 server/mutex.c      |  1 +
 server/named_pipe.c |  5 +++++
 server/object.h     |  3 +++
 server/process.c    |  3 +++
 server/queue.c      |  2 ++
 server/registry.c   |  1 +
 server/request.c    |  1 +
 server/semaphore.c  |  1 +
 server/serial.c     |  1 +
 server/signal.c     |  1 +
 server/sock.c       |  3 +++
 server/symlink.c    |  1 +
 server/thread.c     |  3 +++
 server/timer.c      |  1 +
 server/token.c      |  1 +
 server/window.c     |  1 +
 server/winstation.c | 10 ++++++++++
 33 files changed, 106 insertions(+)

diff --git a/server/async.c b/server/async.c
index 80129ac0ac3..dcc45973c64 100644
--- a/server/async.c
+++ b/server/async.c
@@ -89,6 +89,7 @@ static const struct object_ops async_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     async_destroy              /* destroy */
 };
@@ -698,6 +699,7 @@ static const struct object_ops iosb_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_object_mapping,        /* get_object_mapping */
     no_close_handle,          /* close_handle */
     iosb_destroy              /* destroy */
 };
diff --git a/server/atom.c b/server/atom.c
index ff0799f5880..b2f3105138f 100644
--- a/server/atom.c
+++ b/server/atom.c
@@ -91,6 +91,7 @@ static const struct object_ops atom_table_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     atom_table_destroy            /* destroy */
 };
diff --git a/server/change.c b/server/change.c
index 843e495411c..8cf3c960bf3 100644
--- a/server/change.c
+++ b/server/change.c
@@ -124,6 +124,7 @@ static const struct object_ops dir_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_object_mapping,        /* get_object_mapping */
     dir_close_handle,         /* close_handle */
     dir_destroy               /* destroy */
 };
diff --git a/server/clipboard.c b/server/clipboard.c
index 8118a467dd8..bc12a150cd7 100644
--- a/server/clipboard.c
+++ b/server/clipboard.c
@@ -88,6 +88,7 @@ static const struct object_ops clipboard_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     clipboard_destroy             /* destroy */
 };
diff --git a/server/completion.c b/server/completion.c
index 6933195e72d..8a67a1cbfd8 100644
--- a/server/completion.c
+++ b/server/completion.c
@@ -87,6 +87,7 @@ static const struct object_ops completion_ops =
     default_unlink_name,       /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     completion_destroy         /* destroy */
 };
diff --git a/server/console.c b/server/console.c
index b64283baf4a..b9837c169aa 100644
--- a/server/console.c
+++ b/server/console.c
@@ -93,6 +93,7 @@ static const struct object_ops console_ops =
     NULL,                             /* unlink_name */
     console_open_file,                /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     console_destroy                   /* destroy */
 };
@@ -170,6 +171,7 @@ static const struct object_ops console_server_ops =
     NULL,                             /* unlink_name */
     console_server_open_file,         /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     console_server_destroy            /* destroy */
 };
@@ -239,6 +241,7 @@ static const struct object_ops screen_buffer_ops =
     NULL,                             /* unlink_name */
     screen_buffer_open_file,          /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     screen_buffer_destroy             /* destroy */
 };
@@ -288,6 +291,7 @@ static const struct object_ops console_device_ops =
     default_unlink_name,              /* unlink_name */
     console_device_open_file,         /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     no_destroy                        /* destroy */
 };
@@ -325,6 +329,7 @@ static const struct object_ops console_input_ops =
     default_unlink_name,              /* unlink_name */
     console_input_open_file,          /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     console_input_destroy             /* destroy */
 };
@@ -382,6 +387,7 @@ static const struct object_ops console_output_ops =
     default_unlink_name,              /* unlink_name */
     console_output_open_file,         /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     console_output_destroy            /* destroy */
 };
@@ -440,6 +446,7 @@ static const struct object_ops console_connection_ops =
     default_unlink_name,              /* unlink_name */
     console_connection_open_file,     /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     console_connection_close_handle,  /* close_handle */
     console_connection_destroy        /* destroy */
 };
diff --git a/server/debugger.c b/server/debugger.c
index c59a0abea77..7ca3d5722a4 100644
--- a/server/debugger.c
+++ b/server/debugger.c
@@ -98,6 +98,7 @@ static const struct object_ops debug_event_ops =
     NULL,                          /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    no_object_mapping,             /* get_object_mapping */
     no_close_handle,               /* close_handle */
     debug_event_destroy            /* destroy */
 };
@@ -126,6 +127,7 @@ static const struct object_ops debug_obj_ops =
     default_unlink_name,           /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    no_object_mapping,             /* get_object_mapping */
     no_close_handle,               /* close_handle */
     debug_obj_destroy              /* destroy */
 };
diff --git a/server/device.c b/server/device.c
index 436dac6bfe9..2730d457816 100644
--- a/server/device.c
+++ b/server/device.c
@@ -78,6 +78,7 @@ static const struct object_ops irp_call_ops =
     NULL,                             /* unlink_name */
     no_open_file,                     /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     irp_call_destroy                  /* destroy */
 };
@@ -118,6 +119,7 @@ static const struct object_ops device_manager_ops =
     NULL,                             /* unlink_name */
     no_open_file,                     /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     device_manager_destroy            /* destroy */
 };
@@ -175,6 +177,7 @@ static const struct object_ops device_ops =
     default_unlink_name,              /* unlink_name */
     device_open_file,                 /* open_file */
     device_get_kernel_obj_list,       /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     device_destroy                    /* destroy */
 };
@@ -227,6 +230,7 @@ static const struct object_ops device_file_ops =
     NULL,                             /* unlink_name */
     no_open_file,                     /* open_file */
     device_file_get_kernel_obj_list,  /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     device_file_close_handle,         /* close_handle */
     device_file_destroy               /* destroy */
 };
@@ -253,6 +257,11 @@ struct list *no_kernel_obj_list( struct object *obj )
     return NULL;
 }

+struct mapping *no_object_mapping( struct object *obj )
+{
+    return NULL;
+}
+
 struct kernel_object
 {
     struct device_manager  *manager;
diff --git a/server/directory.c b/server/directory.c
index 23d7eb0a2b7..b16527cee3b 100644
--- a/server/directory.c
+++ b/server/directory.c
@@ -81,6 +81,7 @@ static const struct object_ops object_type_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     no_destroy                    /* destroy */
 };
@@ -131,6 +132,7 @@ static const struct object_ops directory_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     directory_destroy             /* destroy */
 };
diff --git a/server/event.c b/server/event.c
index f1b79b1b35e..ce1adb5a9c5 100644
--- a/server/event.c
+++ b/server/event.c
@@ -84,6 +84,7 @@ static const struct object_ops event_ops =
     default_unlink_name,       /* unlink_name */
     no_open_file,              /* open_file */
     event_get_kernel_obj_list, /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     no_destroy                 /* destroy */
 };
@@ -131,6 +132,7 @@ static const struct object_ops keyed_event_ops =
     default_unlink_name,         /* unlink_name */
     no_open_file,                /* open_file */
     no_kernel_obj_list,          /* get_kernel_obj_list */
+    no_object_mapping,           /* get_object_mapping */
     no_close_handle,             /* close_handle */
     no_destroy                   /* destroy */
 };
diff --git a/server/fd.c b/server/fd.c
index 8576882aaa9..85683ced951 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -181,6 +181,7 @@ static const struct object_ops fd_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_object_mapping,        /* get_object_mapping */
     no_close_handle,          /* close_handle */
     fd_destroy                /* destroy */
 };
@@ -222,6 +223,7 @@ static const struct object_ops device_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_object_mapping,        /* get_object_mapping */
     no_close_handle,          /* close_handle */
     device_destroy            /* destroy */
 };
@@ -262,6 +264,7 @@ static const struct object_ops inode_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_object_mapping,        /* get_object_mapping */
     no_close_handle,          /* close_handle */
     inode_destroy             /* destroy */
 };
@@ -304,6 +307,7 @@ static const struct object_ops file_lock_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_object_mapping,          /* get_object_mapping */
     no_close_handle,            /* close_handle */
     no_destroy                  /* destroy */
 };
diff --git a/server/file.c b/server/file.c
index 76c687833c9..d93b47a0b97 100644
--- a/server/file.c
+++ b/server/file.c
@@ -106,6 +106,7 @@ static const struct object_ops file_ops =
     NULL,                         /* unlink_name */
     file_open_file,               /* open_file */
     file_get_kernel_obj_list,     /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     file_destroy                  /* destroy */
 };
diff --git a/server/handle.c b/server/handle.c
index 71cdd2e328c..e66ab994a11 100644
--- a/server/handle.c
+++ b/server/handle.c
@@ -138,6 +138,7 @@ static const struct object_ops handle_table_ops =
     NULL,                            /* unlink_name */
     no_open_file,                    /* open_file */
     no_kernel_obj_list,              /* get_kernel_obj_list */
+    no_object_mapping,               /* get_object_mapping */
     no_close_handle,                 /* close_handle */
     handle_table_destroy             /* destroy */
 };
diff --git a/server/hook.c b/server/hook.c
index 5abdf39ad37..fd4f5a01224 100644
--- a/server/hook.c
+++ b/server/hook.c
@@ -92,6 +92,7 @@ static const struct object_ops hook_table_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     hook_table_destroy            /* destroy */
 };
diff --git a/server/mailslot.c b/server/mailslot.c
index 2d8697ec9bd..9b856513fcf 100644
--- a/server/mailslot.c
+++ b/server/mailslot.c
@@ -86,6 +86,7 @@ static const struct object_ops mailslot_ops =
     default_unlink_name,       /* unlink_name */
     mailslot_open_file,        /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     mailslot_destroy           /* destroy */
 };
@@ -145,6 +146,7 @@ static const struct object_ops mail_writer_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_object_mapping,          /* get_object_mapping */
     no_close_handle,            /* close_handle */
     mail_writer_destroy         /* destroy */
 };
@@ -208,6 +210,7 @@ static const struct object_ops mailslot_device_ops =
     default_unlink_name,            /* unlink_name */
     mailslot_device_open_file,      /* open_file */
     no_kernel_obj_list,             /* get_kernel_obj_list */
+    no_object_mapping,              /* get_object_mapping */
     no_close_handle,                /* close_handle */
     mailslot_device_destroy         /* destroy */
 };
@@ -238,6 +241,7 @@ static const struct object_ops mailslot_device_file_ops =
     NULL,                                   /* unlink_name */
     no_open_file,                           /* open_file */
     no_kernel_obj_list,                     /* get_kernel_obj_list */
+    no_object_mapping,                      /* get_object_mapping */
     no_close_handle,                        /* close_handle */
     mailslot_device_file_destroy            /* destroy */
 };
diff --git a/server/mapping.c b/server/mapping.c
index 90b9c3bbe57..e06b94b2ffe 100644
--- a/server/mapping.c
+++ b/server/mapping.c
@@ -79,6 +79,7 @@ static const struct object_ops ranges_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     ranges_destroy             /* destroy */
 };
@@ -115,6 +116,7 @@ static const struct object_ops shared_map_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     shared_map_destroy         /* destroy */
 };
@@ -188,6 +190,7 @@ static const struct object_ops mapping_ops =
     default_unlink_name,         /* unlink_name */
     no_open_file,                /* open_file */
     no_kernel_obj_list,          /* get_kernel_obj_list */
+    no_object_mapping,           /* get_object_mapping */
     no_close_handle,             /* close_handle */
     mapping_destroy              /* destroy */
 };
@@ -1315,10 +1318,35 @@ DECL_HANDLER(create_mapping)
     if (root) release_object( root );
 }

+static struct mapping *open_object_mapping( user_handle_t handle, struct unicode_str *name )
+{
+    static const WCHAR object_mappingW[] = {'_','_','w','i','n','e','_','m','a','p','p','i','n','g'};
+    struct mapping *mapping;
+    struct object *object;
+
+    if (name->len != sizeof(object_mappingW) || memcmp( name->str, object_mappingW, name->len )) return NULL;
+    if (!(object = get_handle_obj( current->process, handle, 0, NULL )))
+    {
+        clear_error();
+        return NULL;
+    }
+    mapping = object->ops->get_object_mapping( object );
+    release_object( object );
+    return mapping;
+}
+
 /* open a handle to a mapping */
 DECL_HANDLER(open_mapping)
 {
     struct unicode_str name = get_req_unicode_str();
+    struct mapping *mapping;
+
+    if (req->rootdir && (mapping = open_object_mapping( req->rootdir, &name )))
+    {
+        reply->handle = alloc_handle( current->process, &mapping->obj, req->access, req->attributes );
+        release_object( mapping );
+        return;
+    }

reply->handle = open_object( current->process, req->rootdir, req->access,
                                  &mapping_ops, &name, req->attributes );
diff --git a/server/mutex.c b/server/mutex.c
index af0efe72132..7d48fe9064e 100644
--- a/server/mutex.c
+++ b/server/mutex.c
@@ -85,6 +85,7 @@ static const struct object_ops mutex_ops =
     default_unlink_name,       /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     mutex_destroy              /* destroy */
 };
diff --git a/server/named_pipe.c b/server/named_pipe.c
index f3404a33c3b..ffb6347cbd1 100644
--- a/server/named_pipe.c
+++ b/server/named_pipe.c
@@ -131,6 +131,7 @@ static const struct object_ops named_pipe_ops =
     default_unlink_name,          /* unlink_name */
     named_pipe_open_file,         /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     named_pipe_destroy            /* destroy */
 };
@@ -179,6 +180,7 @@ static const struct object_ops pipe_server_ops =
     NULL,                         /* unlink_name */
     pipe_server_open_file,        /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     async_close_obj_handle,       /* close_handle */
     pipe_server_destroy           /* destroy */
 };
@@ -223,6 +225,7 @@ static const struct object_ops pipe_client_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     async_close_obj_handle,       /* close_handle */
     pipe_end_destroy              /* destroy */
 };
@@ -270,6 +273,7 @@ static const struct object_ops named_pipe_device_ops =
     default_unlink_name,              /* unlink_name */
     named_pipe_device_open_file,      /* open_file */
     no_kernel_obj_list,               /* get_kernel_obj_list */
+    no_object_mapping,                /* get_object_mapping */
     no_close_handle,                  /* close_handle */
     named_pipe_device_destroy         /* destroy */
 };
@@ -301,6 +305,7 @@ static const struct object_ops named_pipe_device_file_ops =
     NULL,                                    /* unlink_name */
     no_open_file,                            /* open_file */
     no_kernel_obj_list,                      /* get_kernel_obj_list */
+    no_object_mapping,                       /* get_object_mapping */
     no_close_handle,                         /* close_handle */
     named_pipe_device_file_destroy           /* destroy */
 };
diff --git a/server/object.h b/server/object.h
index d4d66536b81..d94a1a2d734 100644
--- a/server/object.h
+++ b/server/object.h
@@ -103,6 +103,8 @@ struct object_ops
                                 unsigned int options);
     /* return list of kernel objects */
     struct list *(*get_kernel_obj_list)(struct object *);
+    /* return the memory mapping for the object */
+    struct mapping *(*get_object_mapping)(struct object *);
     /* close a handle to this object */
     int (*close_handle)(struct object *,struct process *,obj_handle_t);
     /* destroy on refcount == 0 */
@@ -181,6 +183,7 @@ extern void default_unlink_name( struct object *obj, struct object_name *name );
 extern struct object *no_open_file( struct object *obj, unsigned int access, unsigned int sharing,
                                     unsigned int options );
 extern struct list *no_kernel_obj_list( struct object *obj );
+extern struct mapping *no_object_mapping( struct object *obj );
 extern int no_close_handle( struct object *obj, struct process *process, obj_handle_t handle );
 extern void no_destroy( struct object *obj );
 #ifdef DEBUG_OBJECTS
diff --git a/server/process.c b/server/process.c
index 3651696f505..eceefc2b274 100644
--- a/server/process.c
+++ b/server/process.c
@@ -117,6 +117,7 @@ static const struct object_ops process_ops =
     NULL,                        /* unlink_name */
     no_open_file,                /* open_file */
     process_get_kernel_obj_list, /* get_kernel_obj_list */
+    no_object_mapping,           /* get_object_mapping */
     no_close_handle,             /* close_handle */
     process_destroy              /* destroy */
 };
@@ -168,6 +169,7 @@ static const struct object_ops startup_info_ops =
     NULL,                          /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    no_object_mapping,             /* get_object_mapping */
     no_close_handle,               /* close_handle */
     startup_info_destroy           /* destroy */
 };
@@ -229,6 +231,7 @@ static const struct object_ops job_ops =
     default_unlink_name,           /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    no_object_mapping,             /* get_object_mapping */
     job_close_handle,              /* close_handle */
     job_destroy                    /* destroy */
 };
diff --git a/server/queue.c b/server/queue.c
index 8067e1b0f31..c4d2fa540b9 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -186,6 +186,7 @@ static const struct object_ops msg_queue_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     msg_queue_destroy          /* destroy */
 };
@@ -223,6 +224,7 @@ static const struct object_ops thread_input_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     thread_input_destroy          /* destroy */
 };
diff --git a/server/registry.c b/server/registry.c
index e88bed1e72e..4af5b8563ec 100644
--- a/server/registry.c
+++ b/server/registry.c
@@ -192,6 +192,7 @@ static const struct object_ops key_ops =
     key_unlink_name,         /* unlink_name */
     no_open_file,            /* open_file */
     no_kernel_obj_list,      /* get_kernel_obj_list */
+    no_object_mapping,       /* get_object_mapping */
     key_close_handle,        /* close_handle */
     key_destroy              /* destroy */
 };
diff --git a/server/request.c b/server/request.c
index 7021741c765..d93e86e3eed 100644
--- a/server/request.c
+++ b/server/request.c
@@ -102,6 +102,7 @@ static const struct object_ops master_socket_ops =
     NULL,                          /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    no_object_mapping,             /* get_object_mapping */
     no_close_handle,               /* close_handle */
     master_socket_destroy          /* destroy */
 };
diff --git a/server/semaphore.c b/server/semaphore.c
index 53b42a886df..eaf909aa551 100644
--- a/server/semaphore.c
+++ b/server/semaphore.c
@@ -82,6 +82,7 @@ static const struct object_ops semaphore_ops =
     default_unlink_name,           /* unlink_name */
     no_open_file,                  /* open_file */
     no_kernel_obj_list,            /* get_kernel_obj_list */
+    no_object_mapping,             /* get_object_mapping */
     no_close_handle,               /* close_handle */
     no_destroy                     /* destroy */
 };
diff --git a/server/serial.c b/server/serial.c
index d665eb7fa35..64af16d6a51 100644
--- a/server/serial.c
+++ b/server/serial.c
@@ -97,6 +97,7 @@ static const struct object_ops serial_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     serial_destroy                /* destroy */
 };
diff --git a/server/signal.c b/server/signal.c
index 19b76d44c16..45c6d77f552 100644
--- a/server/signal.c
+++ b/server/signal.c
@@ -74,6 +74,7 @@ static const struct object_ops handler_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_object_mapping,        /* get_object_mapping */
     no_close_handle,          /* close_handle */
     handler_destroy           /* destroy */
 };
diff --git a/server/sock.c b/server/sock.c
index 3ad1ce39194..614c6871e96 100644
--- a/server/sock.c
+++ b/server/sock.c
@@ -465,6 +465,7 @@ static const struct object_ops sock_ops =
     NULL,                         /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     sock_close_handle,            /* close_handle */
     sock_destroy                  /* destroy */
 };
@@ -3566,6 +3567,7 @@ static const struct object_ops ifchange_ops =
     NULL,                    /* unlink_name */
     no_open_file,            /* open_file */
     no_kernel_obj_list,      /* get_kernel_obj_list */
+    no_object_mapping,       /* get_object_mapping */
     no_close_handle,         /* close_handle */
     ifchange_destroy         /* destroy */
 };
@@ -3787,6 +3789,7 @@ static const struct object_ops socket_device_ops =
     default_unlink_name,        /* unlink_name */
     socket_device_open_file,    /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_object_mapping,          /* get_object_mapping */
     no_close_handle,            /* close_handle */
     no_destroy                  /* destroy */
 };
diff --git a/server/symlink.c b/server/symlink.c
index dd28efd3a75..0492b83172a 100644
--- a/server/symlink.c
+++ b/server/symlink.c
@@ -83,6 +83,7 @@ static const struct object_ops symlink_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     no_close_handle,              /* close_handle */
     symlink_destroy               /* destroy */
 };
diff --git a/server/thread.c b/server/thread.c
index 56f57cefd8f..5673c9d4809 100644
--- a/server/thread.c
+++ b/server/thread.c
@@ -108,6 +108,7 @@ static const struct object_ops thread_apc_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_object_mapping,          /* get_object_mapping */
     no_close_handle,            /* close_handle */
     thread_apc_destroy          /* destroy */
 };
@@ -150,6 +151,7 @@ static const struct object_ops context_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     no_kernel_obj_list,         /* get_kernel_obj_list */
+    no_object_mapping,          /* get_object_mapping */
     no_close_handle,            /* close_handle */
     no_destroy                  /* destroy */
 };
@@ -199,6 +201,7 @@ static const struct object_ops thread_ops =
     NULL,                       /* unlink_name */
     no_open_file,               /* open_file */
     thread_get_kernel_obj_list, /* get_kernel_obj_list */
+    no_object_mapping,          /* get_object_mapping */
     no_close_handle,            /* close_handle */
     destroy_thread              /* destroy */
 };
diff --git a/server/timer.c b/server/timer.c
index 96dc9d00ca1..3f083db56b8 100644
--- a/server/timer.c
+++ b/server/timer.c
@@ -88,6 +88,7 @@ static const struct object_ops timer_ops =
     default_unlink_name,       /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     timer_destroy              /* destroy */
 };
diff --git a/server/token.c b/server/token.c
index 4df8d2e0c6e..94e3fd0b121 100644
--- a/server/token.c
+++ b/server/token.c
@@ -155,6 +155,7 @@ static const struct object_ops token_ops =
     NULL,                      /* unlink_name */
     no_open_file,              /* open_file */
     no_kernel_obj_list,        /* get_kernel_obj_list */
+    no_object_mapping,         /* get_object_mapping */
     no_close_handle,           /* close_handle */
     token_destroy              /* destroy */
 };
diff --git a/server/window.c b/server/window.c
index 242e93f303a..8fb4162f9f4 100644
--- a/server/window.c
+++ b/server/window.c
@@ -119,6 +119,7 @@ static const struct object_ops window_ops =
     NULL,                     /* unlink_name */
     no_open_file,             /* open_file */
     no_kernel_obj_list,       /* get_kernel_obj_list */
+    no_object_mapping,        /* get_object_mapping */
     no_close_handle,          /* close_handle */
     window_destroy            /* destroy */
 };
diff --git a/server/winstation.c b/server/winstation.c
index cedda7d5470..905a560d8d6 100644
--- a/server/winstation.c
+++ b/server/winstation.c
@@ -52,6 +52,7 @@ static struct object *winstation_lookup_name( struct object *obj, struct unicode
 static void winstation_destroy( struct object *obj );
 static void desktop_dump( struct object *obj, int verbose );
 static int desktop_link_name( struct object *obj, struct object_name *name, struct object *parent );
+static struct mapping *desktop_get_object_mapping( struct object *obj );
 static int desktop_close_handle( struct object *obj, struct process *process, obj_handle_t handle );
 static void desktop_destroy( struct object *obj );

@@ -89,6 +90,7 @@ static const struct object_ops winstation_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    no_object_mapping,            /* get_object_mapping */
     winstation_close_handle,      /* close_handle */
     winstation_destroy            /* destroy */
 };
@@ -129,6 +131,7 @@ static const struct object_ops desktop_ops =
     default_unlink_name,          /* unlink_name */
     no_open_file,                 /* open_file */
     no_kernel_obj_list,           /* get_kernel_obj_list */
+    desktop_get_object_mapping,   /* get_object_mapping */
     desktop_close_handle,         /* close_handle */
     desktop_destroy               /* destroy */
 };
@@ -286,6 +289,13 @@ static int desktop_link_name( struct object *obj, struct object_name *name, stru
     return 1;
 }

+static struct mapping *desktop_get_object_mapping( struct object *obj )
+{
+    struct desktop *desktop = (struct desktop *)obj;
+    assert( obj->ops == &desktop_ops );
+    return (struct mapping *)grab_object( desktop->shared_mapping );
+}
+
 static int desktop_close_handle( struct object *obj, struct process *process, obj_handle_t handle )
 {
     struct thread *thread;

[PATCH v16 5/5] user32: Use the desktop shared data for GetCursorPos().

[Rémi Bernon]

From: Rémi Bernon

Based on a patch by Huw Davies .
---
 dlls/win32u/input.c          | 20 ++++++-------
 dlls/win32u/ntuser_private.h |  1 +
 dlls/win32u/sysparams.c      |  1 +
 dlls/win32u/win32u_private.h | 25 ++++++++++++++++
 dlls/win32u/winstation.c     | 55 ++++++++++++++++++++++++++++++++++++
 5 files changed, 91 insertions(+), 11 deletions(-)

diff --git a/dlls/win32u/input.c b/dlls/win32u/input.c
index ef8d564c264..d793ac103e4 100644
--- a/dlls/win32u/input.c
+++ b/dlls/win32u/input.c
@@ -749,25 +749,23 @@ BOOL WINAPI NtUserSetCursorPos( INT x, INT y )
  */
 BOOL get_cursor_pos( POINT *pt )
 {
-    BOOL ret;
+    const desktop_shm_t *shared;
     DWORD last_change;
+    BOOL ret = TRUE;
     UINT dpi;

-    if (!pt) return FALSE;
+    if (!pt || !(shared = get_desktop_shared_memory())) return FALSE;

-    SERVER_START_REQ( set_cursor )
+    SHARED_READ_BEGIN( shared, desktop_shm_t )
     {
-        if ((ret = !wine_server_call( req )))
-        {
-            pt->x = reply->new_x;
-            pt->y = reply->new_y;
-            last_change = reply->last_change;
-        }
+        pt->x = shared->cursor.x;
+        pt->y = shared->cursor.y;
+        last_change = shared->cursor.last_change;
     }
-    SERVER_END_REQ;
+    SHARED_READ_END;

/* query new position from graphics driver if we haven't updated recently */
-    if (ret && NtGetTickCount() - last_change > 100) ret = user_driver->pGetCursorPos( pt );
+    if (NtGetTickCount() - last_change > 100) ret = user_driver->pGetCursorPos( pt );
     if (ret && (dpi = get_thread_dpi()))
     {
         HMONITOR monitor = monitor_from_point( *pt, MONITOR_DEFAULTTOPRIMARY, 0 );
diff --git a/dlls/win32u/ntuser_private.h b/dlls/win32u/ntuser_private.h
index 3b6cab5bdc9..11fc1a19850 100644
--- a/dlls/win32u/ntuser_private.h
+++ b/dlls/win32u/ntuser_private.h
@@ -127,6 +127,7 @@ struct user_thread_info
     UINT                          spy_indent;             /* Current spy indent */
     BOOL                          clipping_cursor;        /* thread is currently clipping */
     DWORD                         clipping_reset;         /* time when clipping was last reset */
+    const desktop_shm_t          *desktop_shm;            /* ptr to server's desktop shared memory */
 };

C_ASSERT( sizeof(struct user_thread_info) <= sizeof(((TEB *)0)->Win32ClientInfo) );
diff --git a/dlls/win32u/sysparams.c b/dlls/win32u/sysparams.c
index 673082056b1..03deb0a224d 100644
--- a/dlls/win32u/sysparams.c
+++ b/dlls/win32u/sysparams.c
@@ -6204,6 +6204,7 @@ static void thread_detach(void)
     destroy_thread_windows();
     cleanup_imm_thread();
     NtClose( thread_info->server_queue );
+    cleanup_thread_desktop();

exiting_thread_id = 0;
 }
diff --git a/dlls/win32u/win32u_private.h b/dlls/win32u/win32u_private.h
index d5f010a8249..edcf45a032e 100644
--- a/dlls/win32u/win32u_private.h
+++ b/dlls/win32u/win32u_private.h
@@ -194,6 +194,8 @@ extern void user_unlock(void);
 extern void user_check_not_lock(void);

/* winstation.c */
+extern const desktop_shm_t *get_desktop_shared_memory(void);
+extern void cleanup_thread_desktop(void);
 extern BOOL is_virtual_desktop(void);

/* window.c */
@@ -362,4 +364,27 @@ static inline BOOL intersect_rect( RECT *dst, const RECT *src1, const RECT *src2
     return !IsRectEmpty( dst );
 }

+#if defined(__i386__) || defined(__x86_64__)
+#define __SHARED_READ_SEQ( x )  (x)
+#define __SHARED_READ_FENCE     do {} while(0)
+#else
+#define __SHARED_READ_SEQ( x )  __atomic_load_n( &(x), __ATOMIC_RELAXED )
+#define __SHARED_READ_FENCE     __atomic_thread_fence( __ATOMIC_ACQUIRE )
+#endif
+
+#define SHARED_READ_BEGIN( ptr, type )                                  \
+    do {                                                                \
+        const type *__shared = (ptr);                                   \
+        unsigned int __seq;                                             \
+        do {                                                            \
+            while ((__seq = __SHARED_READ_SEQ( __shared->seq )) & 1) YieldProcessor(); \
+            __SHARED_READ_FENCE; \
+            do
+
+#define SHARED_READ_END                            \
+            while (0);                             \
+            __SHARED_READ_FENCE;                   \
+        } while (__SHARED_READ_SEQ( __shared->seq ) != __seq); \
+    } while(0)
+
 #endif /* __WINE_WIN32U_PRIVATE */
diff --git a/dlls/win32u/winstation.c b/dlls/win32u/winstation.c
index b187b246941..9012c377f99 100644
--- a/dlls/win32u/winstation.c
+++ b/dlls/win32u/winstation.c
@@ -40,6 +40,60 @@ WINE_DECLARE_DEBUG_CHANNEL(win);

#define DESKTOP_ALL_ACCESS 0x01ff

+static volatile void *map_object_shared_memory( HANDLE object, SIZE_T size )
+{
+    static const WCHAR object_mappingW[] =
+    {
+        '_','_','w','i','n','e','_','m','a','p','p','i','n','g',0
+    };
+    UNICODE_STRING section_str = RTL_CONSTANT_STRING( object_mappingW );
+    OBJECT_ATTRIBUTES attr;
+    HANDLE handle;
+    UINT status;
+    void *ptr;
+
+    InitializeObjectAttributes( &attr, &section_str, 0, object, NULL );
+    if (!(status = NtOpenSection( &handle, SECTION_MAP_READ, &attr )))
+    {
+        ptr = NULL;
+        status = NtMapViewOfSection( handle, GetCurrentProcess(), &ptr, 0, 0, NULL,
+                                     &size, ViewUnmap, 0, PAGE_READONLY );
+        NtClose( handle );
+    }
+
+    if (status)
+    {
+        ERR( "Failed to map object %p mapping, status %#x\n", object, status );
+        return NULL;
+    }
+
+    return ptr;
+}
+
+const desktop_shm_t *get_desktop_shared_memory(void)
+{
+    struct user_thread_info *thread_info = get_user_thread_info();
+
+    if (!thread_info->desktop_shm)
+    {
+        HANDLE desktop = NtUserGetThreadDesktop( GetCurrentThreadId() );
+        thread_info->desktop_shm = map_object_shared_memory( desktop, sizeof(*thread_info->desktop_shm) );
+    }
+
+    return thread_info->desktop_shm;
+}
+
+void cleanup_thread_desktop(void)
+{
+    struct user_thread_info *thread_info = get_user_thread_info();
+
+    if (thread_info->desktop_shm)
+    {
+        NtUnmapViewOfSection( GetCurrentProcess(), (void *)thread_info->desktop_shm );
+        thread_info->desktop_shm = NULL;
+    }
+}
+
 BOOL is_virtual_desktop(void)
 {
     HANDLE desktop = NtUserGetThreadDesktop( GetCurrentThreadId() );
@@ -265,6 +319,7 @@ BOOL WINAPI NtUserSetThreadDesktop( HDESK handle )
         thread_info->client_info.msg_window = 0;
         if (key_state_info) key_state_info->time = 0;
         if (was_virtual_desktop != is_virtual_desktop()) update_display_cache( TRUE );
+        cleanup_thread_desktop();
     }
     return ret;
 }

[PATCH v16 0/6] MR3103: server: Create and use a desktop shared mapping for GetCursorPos.

[Rémi Bernon (＠rbernon)]

Only rebased (please ignore db2b6c49, I messed it up), will address the comments next.