windows/hook.c

   1 /*
   2  * Windows hook functions
   3  *
   4  * Copyright 1994, 1995 Alexandre Julliard
   5  *
   6  * Based on investigations by Alex Korobka
   7  */
   8
   9 /*
  10  * Warning!
  11  * A HHOOK is a 32-bit handle for compatibility with Windows 3.0 where it was
  12  * a pointer to the next function. Now it is in fact composed of a USER heap
  13  * handle in the low 16 bits and of a HOOK_MAGIC value in the high 16 bits
  14  * (except for WINELIB32 where it is a 32-bit handle).  -- AJ
  15  */
  16
  17 #include "hook.h"
  18 #include "message.h"
  19 #include "user.h"
  20 #include "stddebug.h"
  21 #include "debug.h"
  22
  23   /* This should probably reside in USER heap */
  24 static HANDLE HOOK_systemHooks[WH_NB_HOOKS] = { 0, };
  25
  26
  27 /***********************************************************************
  28  *           HOOK_GetNextHook
  29  *
  30  * Get the next hook of a given hook.
  31  */
  32 static HANDLE HOOK_GetNextHook( HANDLE hook )
  33 {
  34     HOOKDATA *data = (HOOKDATA *)USER_HEAP_LIN_ADDR( hook );
  35     if (!data) return 0;
  36     if (data->next) return data->next;
  37     if (!data->ownerQueue) return 0;  /* Already system hook */
  38     /* Now start enumerating the system hooks */
  39     return HOOK_systemHooks[data->id - WH_FIRST_HOOK];
  40 }
  41
  42
  43 /***********************************************************************
  44  *           HOOK_GetHook
  45  *
  46  * Get the first hook for a given type.
  47  */
  48 static HANDLE HOOK_GetHook( short id )
  49 {
  50     MESSAGEQUEUE *queue;
  51     HANDLE hook = 0;
  52
  53     if ((queue = (MESSAGEQUEUE *)GlobalLock( GetTaskQueue(0) )) != NULL)
  54         hook = queue->hooks[id - WH_FIRST_HOOK];
  55     if (!hook) hook = HOOK_systemHooks[id - WH_FIRST_HOOK];
  56     return hook;
  57 }
  58
  59
  60 /***********************************************************************
  61  *           HOOK_SetHook
  62  *
  63  * Install a given hook.
  64  */
  65 HANDLE HOOK_SetHook( short id, HOOKPROC proc, HINSTANCE hInst, HTASK hTask )
  66 {
  67     HOOKDATA *data;
  68     HANDLE handle;
  69     HQUEUE hQueue = 0;
  70
  71     if ((id < WH_FIRST_HOOK) || (id > WH_LAST_HOOK)) return 0;
  72     if (!(hInst = GetExePtr( hInst ))) return 0;
  73
  74     dprintf_hook( stddeb, "Setting hook %d: %08lx "NPFMT" "NPFMT"\n",
  75                   id, (DWORD)proc, hInst, hTask );
  76
  77     if (hTask)  /* Task-specific hook */
  78     {
  79         if ((id == WH_JOURNALRECORD) || (id == WH_JOURNALPLAYBACK) ||
  80             (id == WH_SYSMSGFILTER)) return 0;  /* System-only hooks */
  81         if (!(hQueue = GetTaskQueue( hTask ))) return 0;
  82     }
  83
  84     if (id == WH_JOURNALPLAYBACK || id == WH_CBT ||
  85         id == WH_DEBUG || id == WH_SHELL)
  86     {
  87         fprintf( stdnimp, "Unimplemented hook set: (%d,%08lx,"NPFMT","NPFMT")!\n",
  88                  id, (DWORD)proc, hInst, hTask );
  89     }
  90
  91     /* Create the hook structure */
  92
  93     if (!(handle = (HANDLE)USER_HEAP_ALLOC( sizeof(HOOKDATA) ))) return 0;
  94     data = (HOOKDATA *) USER_HEAP_LIN_ADDR( handle );
  95     data->proc        = proc;
  96     data->id          = id;
  97     data->ownerQueue  = hQueue;
  98     data->ownerModule = hInst;
  99     data->inHookProc  = 0;
 100     dprintf_hook( stddeb, "Setting hook %d: ret="NPFMT"\n", id, handle );
 101
 102     /* Insert it in the correct linked list */
 103
 104     if (hQueue)
 105     {
 106         MESSAGEQUEUE *queue = (MESSAGEQUEUE *)GlobalLock( hQueue );
 107         data->next = queue->hooks[id - WH_FIRST_HOOK];
 108         queue->hooks[id - WH_FIRST_HOOK] = handle;
 109     }
 110     else
 111     {
 112         data->next = HOOK_systemHooks[id - WH_FIRST_HOOK];
 113         HOOK_systemHooks[id - WH_FIRST_HOOK] = handle;
 114     }
 115     return handle;
 116 }
 117
 118
 119 /***********************************************************************
 120  *           HOOK_RemoveHook
 121  *
 122  * Remove a hook from the list.
 123  */
 124 static BOOL HOOK_RemoveHook( HANDLE hook )
 125 {
 126     HOOKDATA *data;
 127     HANDLE *prevHook;
 128
 129     dprintf_hook( stddeb, "Removing hook "NPFMT"\n", hook );
 130
 131     if (!(data = (HOOKDATA *)USER_HEAP_LIN_ADDR(hook))) return FALSE;
 132     if (data->inHookProc)
 133     {
 134         /* Mark it for deletion later on */
 135         dprintf_hook( stddeb, "Hook still running, deletion delayed\n" );
 136         data->proc = (FARPROC)0;
 137         return TRUE;
 138     }
 139
 140     /* Remove it from the linked list */
 141
 142     if (data->ownerQueue)
 143     {
 144         MESSAGEQUEUE *queue = (MESSAGEQUEUE *)GlobalLock( data->ownerQueue );
 145         if (!queue) return FALSE;
 146         prevHook = &queue->hooks[data->id - WH_FIRST_HOOK];
 147     }
 148     else prevHook = &HOOK_systemHooks[data->id - WH_FIRST_HOOK];
 149
 150     while (*prevHook && *prevHook != hook)
 151         prevHook = &((HOOKDATA *)USER_HEAP_LIN_ADDR(*prevHook))->next;
 152
 153      if (!*prevHook) return FALSE;
 154     *prevHook = data->next;
 155     USER_HEAP_FREE( hook );
 156     return TRUE;
 157 }
 158
 159
 160 /***********************************************************************
 161  *           HOOK_CallHook
 162  *
 163  * Call a hook procedure.
 164  */
 165 static DWORD HOOK_CallHook( HANDLE hook, short code,
 166                             WPARAM wParam, LPARAM lParam )
 167 {
 168     HOOKDATA *data;
 169     MESSAGEQUEUE *queue;
 170     HANDLE prevHook;
 171     DWORD ret;
 172
 173     /* Find the first hook with a valid proc */
 174
 175     for (;;)
 176     {
 177         if (!hook) return 0;
 178         if (!(data = (HOOKDATA *)USER_HEAP_LIN_ADDR(hook))) return 0;
 179         if (data->proc) break;
 180         hook = data->next;
 181     }
 182
 183     /* Now call it */
 184
 185     if (!(queue = (MESSAGEQUEUE *)GlobalLock( GetTaskQueue(0) ))) return 0;
 186     prevHook = queue->hCurHook;
 187     queue->hCurHook = hook;
 188     data->inHookProc = 1;
 189
 190     dprintf_hook( stddeb, "Calling hook "NPFMT": %d %04lx %08lx\n",
 191                   hook, code, (DWORD)wParam, lParam );
 192     ret = CallHookProc( data->proc, code, wParam, lParam );
 193     dprintf_hook( stddeb, "Ret hook "NPFMT" = %08lx\n", hook, ret );
 194
 195     data->inHookProc = 0;
 196     queue->hCurHook = prevHook;
 197     if (!data->proc) HOOK_RemoveHook( hook );
 198     return ret;
 199 }
 200
 201
 202 /***********************************************************************
 203  *           HOOK_CallHooks
 204  *
 205  * Call a hook chain.
 206  */
 207 DWORD HOOK_CallHooks( short id, short code, WPARAM wParam, LPARAM lParam )
 208 {
 209     HANDLE hook = HOOK_GetHook( id );
 210     if (!hook) return 0;
 211     return HOOK_CallHook( hook, code, wParam, lParam );
 212 }
 213
 214
 215 /***********************************************************************
 216  *           SetWindowsHook   (USER.121)
 217  */
 218 FARPROC SetWindowsHook( short id, HOOKPROC proc )
 219 {
 220 #ifdef WINELIB
 221     HINSTANCE hInst = 0;
 222 #else
 223     HINSTANCE hInst = FarGetOwner( HIWORD(proc) );
 224 #endif
 225     /* WH_MSGFILTER is the only task-specific hook for SetWindowsHook() */
 226     HTASK hTask = (id == WH_MSGFILTER) ? GetCurrentTask() : 0;
 227
 228     HANDLE handle = HOOK_SetHook( id, proc, hInst, hTask );
 229     if (!handle) return -1;
 230     if (!((HOOKDATA *)USER_HEAP_LIN_ADDR( handle ))->next) return 0;
 231     /* Not sure if the return value is correct; should not matter much
 232      * since it's never used (see DefHookProc). -- AJ */
 233 #ifdef WINELIB32
 234     return (FARPROC)handle;
 235 #else
 236     return (FARPROC)MAKELONG( handle, HOOK_MAGIC );
 237 #endif
 238 }
 239
 240
 241 /***********************************************************************
 242  *           UnhookWindowsHook   (USER.234)
 243  */
 244 BOOL UnhookWindowsHook( short id, HOOKPROC proc )
 245 {
 246     HANDLE hook = HOOK_GetHook( id );
 247
 248     dprintf_hook( stddeb, "UnhookWindowsHook: %d %08lx\n", id, (DWORD)proc );
 249
 250     while (hook)
 251     {
 252         HOOKDATA *data = (HOOKDATA *)USER_HEAP_LIN_ADDR(hook);
 253         if (data->proc == proc) break;
 254         hook = HOOK_GetNextHook( hook );
 255     }
 256     if (!hook) return FALSE;
 257     return HOOK_RemoveHook( hook );
 258 }
 259
 260
 261 /***********************************************************************
 262  *           DefHookProc   (USER.235)
 263  */
 264 DWORD DefHookProc( short code, WORD wParam, DWORD lParam, HHOOK *hhook )
 265 {
 266     /* Note: the *hhook parameter is never used, since we rely on the
 267      * current hook value from the task queue to find the next hook. */
 268     MESSAGEQUEUE *queue;
 269     HANDLE next;
 270
 271     if (!(queue = (MESSAGEQUEUE *)GlobalLock( GetTaskQueue(0) ))) return 0;
 272     if (!(next = HOOK_GetNextHook( queue->hCurHook ))) return 0;
 273     return HOOK_CallHook( next, code, wParam, lParam );
 274 }
 275
 276
 277 /***********************************************************************
 278  *           CallMsgFilter   (USER.123)
 279  */
 280 BOOL CallMsgFilter( SEGPTR msg, short code )
 281 {
 282     if (GetSysModalWindow()) return FALSE;
 283     if (HOOK_CallHooks( WH_SYSMSGFILTER, code, 0, (LPARAM)msg )) return TRUE;
 284     return HOOK_CallHooks( WH_MSGFILTER, code, 0, (LPARAM)msg );
 285 }
 286
 287
 288 /***********************************************************************
 289  *           SetWindowsHookEx   (USER.291)
 290  */
 291 HHOOK SetWindowsHookEx( short id, HOOKPROC proc, HINSTANCE hInst, HTASK hTask )
 292 {
 293     HANDLE handle = HOOK_SetHook( id, proc, hInst, hTask );
 294 #ifdef WINELIB32
 295     return (HHOOK)handle;
 296 #else
 297     return MAKELONG( handle, HOOK_MAGIC );
 298 #endif
 299 }
 300
 301
 302 /***********************************************************************
 303  *           UnhookWindowHookEx   (USER.292)
 304  */
 305 BOOL UnhookWindowsHookEx( HHOOK hhook )
 306 {
 307 #ifdef WINELIB32
 308     return HOOK_RemoveHook( (HANDLE)hhook );
 309 #else
 310     if (HIWORD(hhook) != HOOK_MAGIC) return FALSE;  /* Not a new format hook */
 311     return HOOK_RemoveHook( LOWORD(hhook) );
 312 #endif
 313 }
 314
 315
 316 /***********************************************************************
 317  *           CallNextHookEx   (USER.293)
 318  */
 319 DWORD CallNextHookEx( HHOOK hhook, short code, WPARAM wParam, LPARAM lParam )
 320 {
 321     HANDLE next;
 322     if (HIWORD(hhook) != HOOK_MAGIC) return 0;  /* Not a new format hook */
 323     if (!(next = HOOK_GetNextHook( LOWORD(hhook) ))) return 0;
 324     return HOOK_CallHook( next, code, wParam, lParam );
 325 }