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 #include "stddebug.h"
  15 #include "debug.h"
  16
  17 HHOOK systemHooks[LAST_HOOK-FIRST_HOOK+1] = { 0, };
  18
  19   /* Task-specific hooks should probably be in the task structure */
  20 HHOOK taskHooks[LAST_HOOK-FIRST_HOOK+1] = { 0, };
  21
  22
  23
  24 /***********************************************************************
  25  *           SetWindowsHook   (USER.121)
  26  */
  27 FARPROC SetWindowsHook( short id, HOOKPROC proc )
  28 {
  29   HHOOK hhook = SetWindowsHookEx( id, proc, 0, 0 );
  30   HOOKDATA *data = PTR_SEG_TO_LIN(hhook);
  31   if (data != NULL)  {
  32     data = PTR_SEG_TO_LIN(data->next);
  33     if (data != NULL)  {
  34       return data->proc;
  35     }
  36   }
  37   return 0;
  38 }
  39
  40
  41 /***********************************************************************
  42  *           UnhookWindowsHook   (USER.234)
  43  */
  44 BOOL UnhookWindowsHook( short id, FARPROC hproc )
  45 {
  46   HHOOK *prevHook,hhook;
  47
  48   prevHook = &TASK_HOOK(id);
  49   while (*prevHook)  {
  50     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(*prevHook);
  51
  52     if (data->proc == hproc) {
  53       hhook = *prevHook;
  54       *prevHook = data->next;
  55       USER_HEAP_FREE(LOWORD(hhook));
  56       return TRUE;
  57     }
  58   }
  59   prevHook = &SYSTEM_HOOK(id);
  60   while (*prevHook) {
  61     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(*prevHook);
  62     if (data->proc == hproc) {
  63       hhook = *prevHook;
  64       *prevHook = data->next;
  65       USER_HEAP_FREE(LOWORD(hhook));
  66       return TRUE;
  67     }
  68   }
  69   return FALSE;
  70 }
  71
  72
  73 /***********************************************************************
  74  *           DefHookProc   (USER.235)
  75  */
  76 DWORD DefHookProc( short code, WORD wParam, DWORD lParam, HHOOK *hhook )
  77 {
  78     return CallNextHookEx( *hhook, code, wParam, lParam );
  79 }
  80
  81
  82 /***********************************************************************
  83  *           CallMsgFilter   (USER.123)
  84  */
  85 BOOL CallMsgFilter( SEGPTR msg, short code )
  86 {
  87     if (CALL_SYSTEM_HOOK( WH_SYSMSGFILTER, code, 0, (LPARAM)msg )) return TRUE;
  88     else return CALL_TASK_HOOK( WH_MSGFILTER, code, 0, (LPARAM)msg );
  89 }
  90
  91
  92 /***********************************************************************
  93  *           SetWindowsHookEx   (USER.291)
  94  */
  95 HHOOK SetWindowsHookEx( short id, HOOKPROC proc, HINSTANCE hinst, HTASK htask )
  96 {
  97     HOOKDATA *data;
  98     HANDLE handle;
  99     HHOOK *prevHook;
 100
 101     if ((id < FIRST_HOOK) || (id > LAST_HOOK)) return 0;
 102     if (id != WH_GETMESSAGE && id != WH_CALLWNDPROC) {
 103         fprintf( stdnimp, "Unimplemented hook set: %d!\n", id );
 104     }
 105     if (htask)  /* Task-specific hook */
 106     {
 107         if ((id == WH_JOURNALRECORD) || (id == WH_JOURNALPLAYBACK) ||
 108             (id == WH_SYSMSGFILTER)) return 0;
 109         prevHook = &TASK_HOOK( id );
 110     }
 111     else  /* System-wide hook */
 112     {
 113         prevHook = &SYSTEM_HOOK( id );
 114     }
 115
 116     handle = (HANDLE) USER_HEAP_ALLOC( sizeof(*data) );
 117     if (!handle) return 0;
 118     data   = (HOOKDATA *) USER_HEAP_LIN_ADDR( handle );
 119
 120     data->next  = *prevHook;
 121     data->proc  = proc;
 122     data->id    = id;
 123     data->htask = htask;
 124     *prevHook   = USER_HEAP_SEG_ADDR(handle);
 125     return *prevHook;
 126 }
 127
 128
 129 /***********************************************************************
 130  *           UnhookWindowHookEx   (USER.292)
 131  */
 132 BOOL UnhookWindowsHookEx( HHOOK hhook )
 133 {
 134     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(hhook);
 135     HHOOK *prevHook;
 136
 137     if (!data) return FALSE;
 138     prevHook = data->htask ? &TASK_HOOK(data->id) : &SYSTEM_HOOK(data->id);
 139     while (*prevHook && (*prevHook != hhook)) {
 140         prevHook = &((HOOKDATA *)*prevHook)->next;
 141     }
 142     if (!*prevHook) return FALSE;
 143     *prevHook = data->next;
 144     USER_HEAP_FREE( hhook & 0xffff );
 145     return TRUE;
 146 }
 147
 148
 149 /***********************************************************************
 150  *           CallNextHookEx   (USER.293)
 151  */
 152 DWORD CallNextHookEx( HHOOK hhook, short code, WPARAM wParam, LPARAM lParam )
 153 {
 154     HOOKDATA *data = (HOOKDATA *)PTR_SEG_TO_LIN(hhook);
 155     if (data == NULL || !data->next) return 0;
 156     else return INTERNAL_CALL_HOOK( data->next, code, wParam, lParam );
 157 }