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 HHOOK systemHooks[LAST_HOOK-FIRST_HOOK+1] = { 0, };
  16
  17   /* Task-specific hooks should probably be in the task structure */
  18 HHOOK taskHooks[LAST_HOOK-FIRST_HOOK+1] = { 0, };
  19
  20
  21
  22 /***********************************************************************
  23  *           SetWindowsHook   (USER.121)
  24  */
  25 FARPROC SetWindowsHook( short id, HOOKPROC proc )
  26 {
  27   HHOOK hhook = SetWindowsHookEx( id, proc, 0, 0 );
  28   HOOKDATA *data = PTR_SEG_TO_LIN(hhook);
  29   if (data != NULL)  {
  30     data = PTR_SEG_TO_LIN(data->next);
  31     if (data != NULL)  {
  32       return data->proc;
  33     }
  34   }
  35   return 0;
  36 }
  37
  38
  39 /***********************************************************************
  40  *           UnhookWindowsHook   (USER.234)
  41  */
  42 BOOL UnhookWindowsHook( short id, FARPROC hproc )
  43 {
  44   HHOOK *prevHook,hhook;
  45
  46   prevHook = &TASK_HOOK(id);
  47   while (*prevHook)  {
  48     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(*prevHook);
  49
  50     if (data->proc == hproc) {
  51       hhook = *prevHook;
  52       *prevHook = data->next;
  53       USER_HEAP_FREE(LOWORD(hhook));
  54       return TRUE;
  55     }
  56   }
  57   prevHook = &SYSTEM_HOOK(id);
  58   while (*prevHook) {
  59     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(*prevHook);
  60     if (data->proc == hproc) {
  61       hhook = *prevHook;
  62       *prevHook = data->next;
  63       USER_HEAP_FREE(LOWORD(hhook));
  64       return TRUE;
  65     }
  66   }
  67   return FALSE;
  68 }
  69
  70
  71 /***********************************************************************
  72  *           DefHookProc   (USER.235)
  73  */
  74 DWORD DefHookProc( short code, WORD wParam, DWORD lParam, HHOOK *hhook )
  75 {
  76     return CallNextHookEx( *hhook, code, wParam, lParam );
  77 }
  78
  79
  80 /***********************************************************************
  81  *           CallMsgFilter   (USER.123)
  82  */
  83 BOOL CallMsgFilter( SEGPTR msg, short code )
  84 {
  85     if (CALL_SYSTEM_HOOK( WH_SYSMSGFILTER, code, 0, (LPARAM)msg )) return TRUE;
  86     else return CALL_TASK_HOOK( WH_MSGFILTER, code, 0, (LPARAM)msg );
  87 }
  88
  89
  90 /***********************************************************************
  91  *           SetWindowsHookEx   (USER.291)
  92  */
  93 HHOOK SetWindowsHookEx( short id, HOOKPROC proc, HINSTANCE hinst, HTASK htask )
  94 {
  95     HOOKDATA *data;
  96     HANDLE handle;
  97     HHOOK *prevHook;
  98
  99     if ((id < FIRST_HOOK) || (id > LAST_HOOK)) return 0;
 100     if (htask)  /* Task-specific hook */
 101     {
 102         if ((id == WH_JOURNALRECORD) || (id == WH_JOURNALPLAYBACK) ||
 103             (id == WH_SYSMSGFILTER)) return 0;
 104         prevHook = &TASK_HOOK( id );
 105     }
 106     else  /* System-wide hook */
 107     {
 108         prevHook = &SYSTEM_HOOK( id );
 109     }
 110
 111     handle = (HANDLE) USER_HEAP_ALLOC( sizeof(*data) );
 112     if (!handle) return 0;
 113     data   = (HOOKDATA *) USER_HEAP_LIN_ADDR( handle );
 114
 115     data->next  = *prevHook;
 116     data->proc  = proc;
 117     data->id    = id;
 118     data->htask = htask;
 119     *prevHook   = USER_HEAP_SEG_ADDR(handle);
 120     return *prevHook;
 121 }
 122
 123
 124 /***********************************************************************
 125  *           UnhookWindowHookEx   (USER.292)
 126  */
 127 BOOL UnhookWindowsHookEx( HHOOK hhook )
 128 {
 129     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(hhook);
 130     HHOOK *prevHook;
 131
 132     if (!data) return FALSE;
 133     prevHook = data->htask ? &TASK_HOOK(data->id) : &SYSTEM_HOOK(data->id);
 134     while (*prevHook && (*prevHook != hhook)) {
 135         prevHook = &((HOOKDATA *)*prevHook)->next;
 136     }
 137     if (!*prevHook) return FALSE;
 138     *prevHook = data->next;
 139     USER_HEAP_FREE( hhook & 0xffff );
 140     return TRUE;
 141 }
 142
 143
 144 /***********************************************************************
 145  *           CallNextHookEx   (USER.293)
 146  */
 147 DWORD CallNextHookEx( HHOOK hhook, short code, WPARAM wParam, LPARAM lParam )
 148 {
 149     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(hhook);
 150     if (!data->next) return 0;
 151     else return INTERNAL_CALL_HOOK( data->next, code, wParam, lParam );
 152 }