dlls/rsaenh/handle.c

   1 /*
   2  * dlls/rsaenh/handle.c
   3  * Support code to manage HANDLE tables.
   4  *
   5  * Copyright 1998 Alexandre Julliard
   6  * Copyright 2002-2004 Mike McCormack for CodeWeavers
   7  * Copyright 2004 Michael Jung
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  22  */
  23
  24 #include <string.h>
  25 #include <stdarg.h>
  26
  27 #include "windef.h"
  28 #include "winbase.h"
  29 #include "handle.h"
  30
  31 #include "wine/debug.h"
  32
  33 WINE_DEFAULT_DEBUG_CHANNEL(handle);
  34
  35 #define HANDLE2INDEX(h) ((h)-1)
  36 #define INDEX2HANDLE(i) ((i)+1)
  37
  38 /******************************************************************************
  39  *  init_handle_table
  40  *
  41  * Initializes the HANDLETABLE structure pointed to by lpTable
  42  *
  43  * PARAMS
  44  *  lpTable [I] Pointer to the HANDLETABLE structure, which is to be initalized.
  45  *
  46  * NOTES
  47  *  Note that alloc_handle_table calls init_handle_table on it's own, which
  48  *  means that you only have to call init_handle_table, if you use a global
  49  *  variable of type HANDLETABLE for your handle table. However, in this
  50  *  case you have to call destroy_handle_table when you don't need the table
  51  *  any more.
  52  */
  53 void init_handle_table(HANDLETABLE *lpTable)
  54 {
  55     TRACE("(lpTable=%p)\n", lpTable);
  56
  57     lpTable->paEntries = NULL;
  58     lpTable->iEntries = 0;
  59     lpTable->iFirstFree = 0;
  60     InitializeCriticalSection(&lpTable->mutex);
  61 }
  62
  63 /******************************************************************************
  64  *  destroy_handle_table
  65  *
  66  * Destroys the handle table.
  67  *
  68  * PARAMS
  69  *  lpTable [I] Pointer to the handle table, which is to be destroyed.
  70  *
  71  * NOTES
  72  *  Note that release_handle_table takes care of this.
  73  */
  74 void destroy_handle_table(HANDLETABLE *lpTable)
  75 {
  76     TRACE("(lpTable=%p)\n", lpTable);
  77
  78     HeapFree(GetProcessHeap(), 0, lpTable->paEntries);
  79     DeleteCriticalSection(&lpTable->mutex);
  80 }
  81
  82 /******************************************************************************
  83  *  is_valid_handle
  84  *
  85  * Tests if handle is valid given the specified handle table
  86  *
  87  * PARAMS
  88  *  lpTable [I] Pointer to the handle table, with respect to which the handle's
  89  *              validness is tested.
  90  *  handle  [I] The handle tested for validness.
  91  *  dwType  [I] A magic value that identifies the referenced object's type.
  92  *
  93  * RETURNS
  94  *  non zero,  if handle is valid.
  95  *  zero,      if handle is not valid.
  96  */
  97 int is_valid_handle(HANDLETABLE *lpTable, unsigned int handle, DWORD dwType)
  98 {
  99     unsigned int index = HANDLE2INDEX(handle);
 100     int ret = 0;
 101
 102     TRACE("(lpTable=%p, handle=%d)\n", lpTable, handle);
 103
 104     EnterCriticalSection(&lpTable->mutex);
 105
 106     /* We don't use zero handle values */
 107     if (!handle) goto exit;
 108
 109     /* Check for index out of table bounds */
 110     if (index >= lpTable->iEntries) goto exit;
 111
 112     /* Check if this handle is currently allocated */
 113     if (!lpTable->paEntries[index].pObject) goto exit;
 114
 115     /* Check if this handle references an object of the correct type. */
 116     if (lpTable->paEntries[index].pObject->dwType != dwType) goto exit;
 117
 118     ret = 1;
 119 exit:
 120     LeaveCriticalSection(&lpTable->mutex);
 121     return ret;
 122 }
 123
 124 /******************************************************************************
 125  *  alloc_handle_table
 126  *
 127  * Allocates a new handle table
 128  *
 129  * PARAMS
 130  *  lplpTable [O] Pointer to the variable, to which the pointer to the newly
 131  *                allocated handle table is written.
 132  * RETURNS
 133  *  non zero,  if successful
 134  *  zero,      if not successful (out of process heap memory)
 135  *
 136  * NOTES
 137  *  If all you need is a single handle table, you may as well declare a global
 138  *  variable of type HANDLETABLE and call init_handle_table on your own.
 139  */
 140 int alloc_handle_table(HANDLETABLE **lplpTable)
 141 {
 142     TRACE("(lplpTable=%p)\n", lplpTable);
 143
 144     *lplpTable = HeapAlloc(GetProcessHeap(), 0, sizeof(HANDLETABLE));
 145     if (*lplpTable)
 146     {
 147         init_handle_table(*lplpTable);
 148         return 1;
 149     }
 150     else
 151         return 0;
 152 }
 153
 154 /******************************************************************************
 155  *  release_handle_table
 156  *
 157  * Releases a handle table and frees the resources it used.
 158  *
 159  * PARAMS
 160  *  lpTable [I] Pointer to the handle table, which is to be released.
 161  *
 162  * RETURNS
 163  *  non zero,  if successful
 164  *  zero,      if not successful
 165  *
 166  * NOTES
 167  *   All valid handles still in the table are released also.
 168  */
 169 int release_handle_table(HANDLETABLE *lpTable)
 170 {
 171     TRACE("(lpTable=%p)\n", lpTable);
 172
 173     release_all_handles(lpTable);
 174     destroy_handle_table(lpTable);
 175     return (int)HeapFree(GetProcessHeap(), 0, lpTable);
 176 }
 177
 178 /******************************************************************************
 179  *  grow_handle_table [Internal]
 180  *
 181  * Grows the number of entries in the given table by TABLE_SIZE_INCREMENT
 182  *
 183  * PARAMS
 184  *  lpTable [I] Pointer to the table, which is to be grown
 185  *
 186  * RETURNS
 187  *  non zero,  if successful
 188  *  zero,      if not successful (out of memory on process heap)
 189  *
 190  * NOTES
 191  *  This is a support function for alloc_handle. Do not call!
 192  */
 193 static int grow_handle_table(HANDLETABLE *lpTable)
 194 {
 195     HANDLETABLEENTRY *newEntries;
 196     unsigned int i, newIEntries;
 197
 198     newIEntries = lpTable->iEntries + TABLE_SIZE_INCREMENT;
 199
 200     newEntries = HeapAlloc(GetProcessHeap(), 0, sizeof(HANDLETABLEENTRY)*newIEntries);
 201     if (!newEntries)
 202         return 0;
 203
 204     if (lpTable->paEntries)
 205     {
 206         memcpy(newEntries, lpTable->paEntries, sizeof(HANDLETABLEENTRY)*lpTable->iEntries);
 207         HeapFree(GetProcessHeap(), 0, lpTable->paEntries);
 208     }
 209
 210     for (i=lpTable->iEntries; i<newIEntries; i++)
 211     {
 212         newEntries[i].pObject = NULL;
 213         newEntries[i].iNextFree = i+1;
 214     }
 215
 216     lpTable->paEntries = newEntries;
 217     lpTable->iEntries = newIEntries;
 218
 219     return 1;
 220 }
 221
 222 /******************************************************************************
 223  *  alloc_handle
 224  *
 225  * Allocates a new handle to the specified object in a given handle table.
 226  *
 227  * PARAMS
 228  *  lpTable  [I] Pointer to the handle table, from which the new handle is
 229  *               allocated.
 230  *  lpObject [I] Pointer to the object, for which a handle shall be allocated.
 231  *  lpHandle [O] Pointer to a handle variable, into which the handle value will
 232  *               be stored. If not successful, this will be
 233  *               INVALID_HANDLE_VALUE
 234  * RETURNS
 235  *  non zero,  if successful
 236  *  zero,      if not successful (no free handle)
 237  */
 238 int alloc_handle(HANDLETABLE *lpTable, OBJECTHDR *lpObject, unsigned int *lpHandle)
 239 {
 240     int ret = 0;
 241
 242     TRACE("(lpTable=%p, lpObject=%p, lpHandle=%p)\n", lpTable, lpObject, lpHandle);
 243
 244     EnterCriticalSection(&lpTable->mutex);
 245     if (lpTable->iFirstFree >= lpTable->iEntries)
 246         if (!grow_handle_table(lpTable))
 247         {
 248             *lpHandle = (unsigned int)INVALID_HANDLE_VALUE;
 249             goto exit;
 250         }
 251
 252     *lpHandle = INDEX2HANDLE(lpTable->iFirstFree);
 253
 254     lpTable->paEntries[lpTable->iFirstFree].pObject = lpObject;
 255     lpTable->iFirstFree = lpTable->paEntries[lpTable->iFirstFree].iNextFree;
 256     InterlockedIncrement(&lpObject->refcount);
 257
 258     ret = 1;
 259 exit:
 260     LeaveCriticalSection(&lpTable->mutex);
 261     return ret;
 262 }
 263
 264 /******************************************************************************
 265  *  release_handle
 266  *
 267  * Releases resources occupied by the specified handle in the given table.
 268  * The reference count of the handled object is decremented. If it becomes
 269  * zero and if the 'destructor' function pointer member is non NULL, the
 270  * destructor function will be called. Note that release_handle does not
 271  * release resources other than the handle itself. If this is wanted, do it
 272  * in the destructor function.
 273  *
 274  * PARAMS
 275  *  lpTable [I] Pointer to the handle table, from which a handle is to be
 276  *              released.
 277  *  handle  [I] The handle, which is to be released
 278  *  dwType  [I] Identifier for the type of the object, for which a handle is
 279  *              to be released.
 280  *
 281  * RETURNS
 282  *  non zero,  if successful
 283  *  zero,      if not successful (invalid handle)
 284  */
 285 int release_handle(HANDLETABLE *lpTable, unsigned int handle, DWORD dwType)
 286 {
 287     unsigned int index = HANDLE2INDEX(handle);
 288     OBJECTHDR *pObject;
 289     int ret = 0;
 290
 291     TRACE("(lpTable=%p, hande=%d)\n", lpTable, handle);
 292
 293     EnterCriticalSection(&lpTable->mutex);
 294
 295     if (!is_valid_handle(lpTable, handle, dwType))
 296         goto exit;
 297
 298     pObject = lpTable->paEntries[index].pObject;
 299     if (InterlockedDecrement(&pObject->refcount) == 0)
 300     {
 301         TRACE("destroying handle %d\n", handle);
 302         if (pObject->destructor)
 303             pObject->destructor(pObject);
 304     }
 305
 306     lpTable->paEntries[index].pObject = NULL;
 307     lpTable->paEntries[index].iNextFree = lpTable->iFirstFree;
 308     lpTable->iFirstFree = index;
 309
 310     ret = 1;
 311 exit:
 312     LeaveCriticalSection(&lpTable->mutex);
 313     return ret;
 314 }
 315
 316 /******************************************************************************
 317  *  release_all_handles
 318  *
 319  * Releases all valid handles in the given handle table and shrinks the table
 320  * to zero size.
 321  *
 322  * PARAMS
 323  *  lpTable [I] The table of which all valid handles shall be released.
 324  */
 325 void release_all_handles(HANDLETABLE *lpTable)
 326 {
 327     unsigned int i;
 328
 329     TRACE("(lpTable=%p)\n", lpTable);
 330
 331     EnterCriticalSection(&lpTable->mutex);
 332     for (i=0; i<lpTable->iEntries; i++)
 333         if (lpTable->paEntries[i].pObject)
 334             release_handle(lpTable, lpTable->paEntries[i].pObject->dwType, INDEX2HANDLE(i));
 335     LeaveCriticalSection(&lpTable->mutex);
 336 }
 337
 338 /******************************************************************************
 339  *  lookup_handle
 340  *
 341  * Returns the object identified by the handle in the given handle table
 342  *
 343  * PARAMS
 344  *  lpTable    [I] Pointer to the handle table, in which the handle is looked up.
 345  *  handle     [I] The handle, which is to be looked up
 346  *    lplpObject [O] Pointer to the variable, into which the pointer to the
 347  *                   object looked up is copied.
 348  * RETURNS
 349  *  non zero,  if successful
 350  *  zero,      if not successful (invalid handle)
 351  */
 352 int lookup_handle(HANDLETABLE *lpTable, unsigned int handle, DWORD dwType, OBJECTHDR **lplpObject)
 353 {
 354     int ret = 0;
 355
 356     TRACE("(lpTable=%p, handle=%d, lplpObject=%p)\n", lpTable, handle, lplpObject);
 357
 358     EnterCriticalSection(&lpTable->mutex);
 359     if (!is_valid_handle(lpTable, handle, dwType))
 360     {
 361         *lplpObject = NULL;
 362         goto exit;
 363     }
 364     *lplpObject = lpTable->paEntries[HANDLE2INDEX(handle)].pObject;
 365
 366     ret = 1;
 367 exit:
 368     LeaveCriticalSection(&lpTable->mutex);
 369     return ret;
 370 }
 371
 372 /******************************************************************************
 373  *  copy_handle
 374  *
 375  * Copies a handle. Increments the reference count of the object referenced
 376  * by the handle.
 377  *
 378  * PARAMS
 379  *  lpTable [I] Pointer to the handle table, which holds the handle to be copied.
 380  *  handle  [I] The handle to be copied.
 381  *  copy    [O] Pointer to a handle variable, where the copied handle is put.
 382  *
 383  * RETURNS
 384  *  non zero,  if successful
 385  *  zero,      if not successful (invalid handle or out of memory)
 386  */
 387 int copy_handle(HANDLETABLE *lpTable, unsigned int handle, DWORD dwType, unsigned int *copy)
 388 {
 389     OBJECTHDR *pObject;
 390     int ret;
 391
 392     TRACE("(lpTable=%p, handle=%d, copy=%p)\n", lpTable, handle, copy);
 393
 394     EnterCriticalSection(&lpTable->mutex);
 395     if (!lookup_handle(lpTable, handle, dwType, &pObject))
 396     {
 397         *copy = (unsigned int)INVALID_HANDLE_VALUE;
 398         LeaveCriticalSection(&lpTable->mutex);
 399         return 0;
 400     }
 401
 402     ret = alloc_handle(lpTable, pObject, copy);
 403     LeaveCriticalSection(&lpTable->mutex);
 404     return ret;
 405 }
 406
 407 /******************************************************************************
 408  *  new_object
 409  *
 410  * Allocates a new object of size cbSize on the current process's heap.
 411  * Initializes the object header using the destructor and dwType params.
 412  * Allocates a handle to the object in the handle table pointed to by lpTable.
 413  * Returns a pointer to the created object in ppObject.
 414  * Returns a handle to the created object.
 415  *
 416  * PARAMS
 417  *  lpTable    [I] Pointer to the handle table, from which a handle is to be
 418  *              allocated.
 419  *  cbSize     [I] Size of the object to be allocated in bytes.
 420  *  dwType     [I] Object type; will be copied to the object header.
 421  *  destructor [I] Function pointer to a destructor function. Will be called
 422  *                 once the object's reference count gets zero.
 423  *  ppObject   [O] Pointer to a pointer variable, where a pointer to the newly
 424  *                 created object will be stored. You may set this to NULL.
 425  *
 426  * RETURNS
 427  *  INVALID_HANDLE_VALUE,        if something went wrong.
 428  *  a handle to the new object,  if successful.
 429  */
 430 unsigned int new_object(HANDLETABLE *lpTable, size_t cbSize, DWORD dwType, DESTRUCTOR destructor,
 431                         OBJECTHDR **ppObject)
 432 {
 433     OBJECTHDR *pObject;
 434     unsigned int hObject;
 435
 436     if (ppObject)
 437         *ppObject = NULL;
 438
 439     pObject = HeapAlloc(GetProcessHeap(), 0, cbSize);
 440     if (!pObject)
 441         return (unsigned int)INVALID_HANDLE_VALUE;
 442
 443     pObject->dwType = dwType;
 444     pObject->refcount = 0;
 445     pObject->destructor = destructor;
 446
 447     if (!alloc_handle(lpTable, pObject, &hObject))
 448         HeapFree(GetProcessHeap(), 0, pObject);
 449     else
 450         if (ppObject)
 451             *ppObject = pObject;
 452
 453     return hObject;
 454 }