From: Rémi Bernon rbernon@codeweavers.com
--- dlls/win32u/win32u_private.h | 23 +++++++ dlls/win32u/winstation.c | 112 ++++++++++++++++++++++++++++++++++- 2 files changed, 134 insertions(+), 1 deletion(-)
diff --git a/dlls/win32u/win32u_private.h b/dlls/win32u/win32u_private.h index 0af6960a3eb..003d2fd5c24 100644 --- a/dlls/win32u/win32u_private.h +++ b/dlls/win32u/win32u_private.h @@ -364,4 +364,27 @@ static inline BOOL intersect_rect( RECT *dst, const RECT *src1, const RECT *src2 return !IsRectEmpty( dst ); }
+#if defined(__i386__) || defined(__x86_64__) +/* this prevents compilers from incorrectly reordering non-volatile reads (e.g., memcpy) from shared memory */ +#define __SHARED_READ_FENCE do { __asm__ __volatile__( "" ::: "memory" ); } while (0) +#else +#define __SHARED_READ_FENCE __atomic_thread_fence( __ATOMIC_ACQUIRE ) +#endif + +#define SHARED_READ_BEGIN( ptr, type ) \ + do { \ + const type *shared = (ptr); \ + LONG64 __seq; \ + do { \ + while ((__seq = ReadNoFence64( &shared->obj.seq )) & 1) \ + YieldProcessor(); \ + __SHARED_READ_FENCE; \ + do + +#define SHARED_READ_END \ + while (0); \ + __SHARED_READ_FENCE; \ + } while (ReadNoFence64( &shared->obj.seq ) != __seq); \ + } while(0) + #endif /* __WINE_WIN32U_PRIVATE */ diff --git a/dlls/win32u/winstation.c b/dlls/win32u/winstation.c index 6ddd5411f94..aec8fcee067 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 +43,109 @@ WINE_DECLARE_DEBUG_CHANNEL(win);
#define DESKTOP_ALL_ACCESS 0x01ff
+struct shared_session +{ + LONG ref; + UINT64 id; + UINT object_capacity; + const session_shm_t *shared; +}; + +static pthread_mutex_t session_lock = PTHREAD_MUTEX_INITIALIZER; +static struct shared_session *shared_session; + +static struct shared_session *shared_session_acquire( struct shared_session *session ) +{ + int ref = InterlockedIncrement( &session->ref ); + TRACE( "session %p incrementing ref to %d\n", session, ref ); + return session; +} + +static void shared_session_release( struct shared_session *session ) +{ + int ref = InterlockedDecrement( &session->ref ); + TRACE( "session %p decrementing ref to %d\n", session, ref ); + if (!ref) + { + NtUnmapViewOfSection( GetCurrentProcess(), (void *)session->shared ); + free( session ); + } +} + +static NTSTATUS map_shared_session_section( struct shared_session *session, HANDLE handle ) +{ + NTSTATUS status; + SIZE_T size = 0; + + while (!(status = NtMapViewOfSection( handle, GetCurrentProcess(), (void **)&session->shared, 0, 0, + NULL, &size, ViewUnmap, 0, PAGE_READONLY ))) + { + BOOL valid; + session->object_capacity = (size - offsetof(session_shm_t, objects[0])) / sizeof(session_obj_t); + SHARED_READ_BEGIN( session->shared, session_shm_t ) + { + valid = session->object_capacity == shared->object_capacity; + session->id = shared->obj.id; + } + SHARED_READ_END; + if (valid) break; + + NtUnmapViewOfSection( GetCurrentProcess(), (void *)session->shared ); + session->shared = NULL; + size = 0; + } + + return status; +} + +static struct shared_session *get_shared_session( BOOL force ) +{ + struct shared_session *session; + + pthread_mutex_lock( &session_lock ); + + if (force || !shared_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; + + if (!(session = calloc( 1, sizeof(*session) ))) goto done; + session->ref = 1; + + InitializeObjectAttributes( &attr, &name, 0, NULL, NULL ); + if (!(status = NtOpenSection( &handle, SECTION_MAP_READ, &attr ))) + { + status = map_shared_session_section( session, handle ); + NtClose( handle ); + } + + if (status) + { + ERR( "Failed to map session mapping, status %#x\n", status ); + free( session ); + session = NULL; + goto done; + } + + if (shared_session) shared_session_release( shared_session ); + shared_session = session; + } + + session = shared_session_acquire( shared_session ); + +done: + pthread_mutex_unlock( &session_lock ); + + return session; +} + BOOL is_virtual_desktop(void) { HANDLE desktop = NtUserGetThreadDesktop( GetCurrentThreadId() ); @@ -630,12 +736,16 @@ void winstation_init(void) { RTL_USER_PROCESS_PARAMETERS *params = NtCurrentTeb()->Peb->ProcessParameters; WCHAR *winstation = NULL, *desktop = NULL, *buffer = NULL; + struct shared_session *session; HANDLE handle, dir = NULL; OBJECT_ATTRIBUTES attr; UNICODE_STRING str;
static const WCHAR winsta0[] = {'W','i','n','S','t','a','0',0};
+ if ((session = get_shared_session( FALSE ))) + shared_session_release( session ); + if (params->Desktop.Length) { buffer = malloc( params->Desktop.Length + sizeof(WCHAR) );