windows/hook.c

   1 /*
   2  * Windows hook functions
   3  *
   4  * Copyright 1994 Alexandre Julliard
   5  */
   6
   7 /* Warning!
   8  * HHOOK is not a real handle, but a 32-bit pointer to a HOOKDATA structure.
   9  * This is for compatibility with Windows 3.0 where HHOOK was a HOOKPROC.
  10  */
  11
  12 #include "hook.h"
  13 #include "user.h"
  14
  15
  16 HHOOK systemHooks[LAST_HOOK-FIRST_HOOK+1] = { 0, };
  17
  18   /* Task-specific hooks should probably be in the task structure */
  19 HHOOK taskHooks[LAST_HOOK-FIRST_HOOK+1] = { 0, };
  20
  21
  22
  23 /***********************************************************************
  24  *           SetWindowsHook   (USER.121)
  25  */
  26 HHOOK SetWindowsHook( short id, HOOKPROC proc )
  27 {
  28     return SetWindowsHookEx( id, proc, 0, 0 );
  29 }
  30
  31
  32 /***********************************************************************
  33  *           UnhookWindowsHook   (USER.234)
  34  */
  35 BOOL UnhookWindowsHook( short id, HHOOK hhook )
  36 {
  37     return UnhookWindowsHookEx( hhook );
  38 }
  39
  40
  41 /***********************************************************************
  42  *           DefHookProc   (USER.235)
  43  */
  44 DWORD DefHookProc( short code, WORD wParam, DWORD lParam, HHOOK *hhook )
  45 {
  46     return CallNextHookEx( *hhook, code, wParam, lParam );
  47 }
  48
  49
  50 /***********************************************************************
  51  *           CallMsgFilter   (USER.123)
  52  */
  53 BOOL CallMsgFilter( SEGPTR msg, short code )
  54 {
  55     if (CALL_SYSTEM_HOOK( WH_SYSMSGFILTER, code, 0, (LPARAM)msg )) return TRUE;
  56     else return CALL_TASK_HOOK( WH_MSGFILTER, code, 0, (LPARAM)msg );
  57 }
  58
  59
  60 /***********************************************************************
  61  *           SetWindowsHookEx   (USER.291)
  62  */
  63 HHOOK SetWindowsHookEx( short id, HOOKPROC proc, HINSTANCE hinst, HTASK htask )
  64 {
  65     HOOKDATA *data;
  66     HANDLE handle;
  67     HHOOK *prevHook;
  68
  69     if ((id < FIRST_HOOK) || (id > LAST_HOOK)) return 0;
  70     if (htask)  /* Task-specific hook */
  71     {
  72         if ((id == WH_JOURNALRECORD) || (id == WH_JOURNALPLAYBACK) ||
  73             (id == WH_SYSMSGFILTER)) return 0;
  74         prevHook = &TASK_HOOK( id );
  75     }
  76     else  /* System-wide hook */
  77     {
  78         prevHook = &SYSTEM_HOOK( id );
  79     }
  80
  81     handle = (HANDLE) USER_HEAP_ALLOC( sizeof(*data) );
  82     if (!handle) return 0;
  83     data   = (HOOKDATA *) USER_HEAP_LIN_ADDR( handle );
  84
  85     data->next  = *prevHook;
  86     data->proc  = proc;
  87     data->id    = id;
  88     data->htask = htask;
  89     *prevHook   = USER_HEAP_SEG_ADDR(handle);
  90     return *prevHook;
  91 }
  92
  93
  94 /***********************************************************************
  95  *           UnhookWindowHookEx   (USER.292)
  96  */
  97 BOOL UnhookWindowsHookEx( HHOOK hhook )
  98 {
  99     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(hhook);
 100     HHOOK *prevHook;
 101
 102     if (!data) return FALSE;
 103     prevHook = data->htask ? &TASK_HOOK(data->id) : &SYSTEM_HOOK(data->id);
 104     while (*prevHook && (*prevHook != hhook))
 105         prevHook = &((HOOKDATA *)*prevHook)->next;
 106     if (!*prevHook) return FALSE;
 107     *prevHook = data->next;
 108     USER_HEAP_FREE( hhook & 0xffff );
 109     return TRUE;
 110 }
 111
 112
 113 /***********************************************************************
 114  *           CallNextHookEx   (USER.293)
 115  */
 116 DWORD CallNextHookEx( HHOOK hhook, short code, WPARAM wParam, LPARAM lParam )
 117 {
 118     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(hhook);
 119     if (!data->next) return 0;
 120     else return INTERNAL_CALL_HOOK( data->next, code, wParam, lParam );
 121 }