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  *  You have to call destroy_handle_table when you don't need the table
  48  *  any more.
  49  */
  50 void init_handle_table(struct handle_table *lpTable)
  51 {
  52     TRACE("(lpTable=%p)\n", lpTable);
  53
  54     lpTable->paEntries = NULL;
  55     lpTable->iEntries = 0;
  56     lpTable->iFirstFree = 0;
  57     InitializeCriticalSection(&lpTable->mutex);
  58     lpTable->mutex.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": HANDLETABLE.mutex");
  59 }
  60
  61 /******************************************************************************
  62  *  destroy_handle_table
  63  *
  64  * Destroys the handle table.
  65  *
  66  * PARAMS
  67  *  lpTable [I] Pointer to the handle table, which is to be destroyed.
  68  */
  69 void destroy_handle_table(struct handle_table *lpTable)
  70 {
  71     TRACE("(lpTable=%p)\n", lpTable);
  72
  73     HeapFree(GetProcessHeap(), 0, lpTable->paEntries);
  74     lpTable->mutex.DebugInfo->Spare[0] = 0;
  75     DeleteCriticalSection(&lpTable->mutex);
  76 }
  77
  78 /******************************************************************************
  79  *  is_valid_handle
  80  *
  81  * Tests if handle is valid given the specified handle table
  82  *
  83  * PARAMS
  84  *  lpTable [I] Pointer to the handle table, with respect to which the handle's
  85  *              validness is tested.
  86  *  handle  [I] The handle tested for validness.
  87  *  dwType  [I] A magic value that identifies the referenced object's type.
  88  *
  89  * RETURNS
  90  *  non zero,  if handle is valid.
  91  *  zero,      if handle is not valid.
  92  */
  93 int is_valid_handle(struct handle_table *lpTable, HCRYPTKEY handle, DWORD dwType)
  94 {
  95     unsigned int index = HANDLE2INDEX(handle);
  96     int ret = 0;
  97
  98     TRACE("(lpTable=%p, handle=%ld)\n", lpTable, handle);
  99
 100     EnterCriticalSection(&lpTable->mutex);
 101
 102     /* We don't use zero handle values */
 103     if (!handle) goto exit;
 104
 105     /* Check for index out of table bounds */
 106     if (index >= lpTable->iEntries) goto exit;
 107
 108     /* Check if this handle is currently allocated */
 109     if (!lpTable->paEntries[index].pObject) goto exit;
 110
 111     /* Check if this handle references an object of the correct type. */
 112     if (lpTable->paEntries[index].pObject->dwType != dwType) goto exit;
 113
 114     ret = 1;
 115 exit:
 116     LeaveCriticalSection(&lpTable->mutex);
 117     return ret;
 118 }
 119
 120 /******************************************************************************
 121  *  grow_handle_table [Internal]
 122  *
 123  * Grows the number of entries in the given table by TABLE_SIZE_INCREMENT
 124  *
 125  * PARAMS
 126  *  lpTable [I] Pointer to the table, which is to be grown
 127  *
 128  * RETURNS
 129  *  non zero,  if successful
 130  *  zero,      if not successful (out of memory on process heap)
 131  *
 132  * NOTES
 133  *  This is a support function for alloc_handle. Do not call!
 134  */
 135 static int grow_handle_table(struct handle_table *lpTable)
 136 {
 137     struct handle_table_entry *newEntries;
 138     unsigned int i, newIEntries;
 139
 140     newIEntries = lpTable->iEntries + TABLE_SIZE_INCREMENT;
 141
 142     newEntries = HeapAlloc(GetProcessHeap(), 0, sizeof(struct handle_table_entry)*newIEntries);
 143     if (!newEntries)
 144         return 0;
 145
 146     if (lpTable->paEntries)
 147     {
 148         memcpy(newEntries, lpTable->paEntries, sizeof(struct handle_table_entry)*lpTable->iEntries);
 149         HeapFree(GetProcessHeap(), 0, lpTable->paEntries);
 150     }
 151
 152     for (i=lpTable->iEntries; i<newIEntries; i++)
 153     {
 154         newEntries[i].pObject = NULL;
 155         newEntries[i].iNextFree = i+1;
 156     }
 157
 158     lpTable->paEntries = newEntries;
 159     lpTable->iEntries = newIEntries;
 160
 161     return 1;
 162 }
 163
 164 /******************************************************************************
 165  *  alloc_handle
 166  *
 167  * Allocates a new handle to the specified object in a given handle table.
 168  *
 169  * PARAMS
 170  *  lpTable  [I] Pointer to the handle table, from which the new handle is
 171  *               allocated.
 172  *  lpObject [I] Pointer to the object, for which a handle shall be allocated.
 173  *  lpHandle [O] Pointer to a handle variable, into which the handle value will
 174  *               be stored. If not successful, this will be
 175  *               INVALID_HANDLE_VALUE
 176  * RETURNS
 177  *  non zero,  if successful
 178  *  zero,      if not successful (no free handle)
 179  */
 180 static int alloc_handle(struct handle_table *lpTable, OBJECTHDR *lpObject, HCRYPTKEY *lpHandle)
 181 {
 182     int ret = 0;
 183
 184     TRACE("(lpTable=%p, lpObject=%p, lpHandle=%p)\n", lpTable, lpObject, lpHandle);
 185
 186     EnterCriticalSection(&lpTable->mutex);
 187     if (lpTable->iFirstFree >= lpTable->iEntries)
 188         if (!grow_handle_table(lpTable))
 189         {
 190             *lpHandle = (HCRYPTKEY)INVALID_HANDLE_VALUE;
 191             goto exit;
 192         }
 193
 194     *lpHandle = INDEX2HANDLE(lpTable->iFirstFree);
 195
 196     lpTable->paEntries[lpTable->iFirstFree].pObject = lpObject;
 197     lpTable->iFirstFree = lpTable->paEntries[lpTable->iFirstFree].iNextFree;
 198     InterlockedIncrement(&lpObject->refcount);
 199
 200     ret = 1;
 201 exit:
 202     LeaveCriticalSection(&lpTable->mutex);
 203     return ret;
 204 }
 205
 206 /******************************************************************************
 207  *  release_handle
 208  *
 209  * Releases resources occupied by the specified handle in the given table.
 210  * The reference count of the handled object is decremented. If it becomes
 211  * zero and if the 'destructor' function pointer member is non NULL, the
 212  * destructor function will be called. Note that release_handle does not
 213  * release resources other than the handle itself. If this is wanted, do it
 214  * in the destructor function.
 215  *
 216  * PARAMS
 217  *  lpTable [I] Pointer to the handle table, from which a handle is to be
 218  *              released.
 219  *  handle  [I] The handle, which is to be released
 220  *  dwType  [I] Identifier for the type of the object, for which a handle is
 221  *              to be released.
 222  *
 223  * RETURNS
 224  *  non zero,  if successful
 225  *  zero,      if not successful (invalid handle)
 226  */
 227 int release_handle(struct handle_table *lpTable, HCRYPTKEY handle, DWORD dwType)
 228 {
 229     unsigned int index = HANDLE2INDEX(handle);
 230     OBJECTHDR *pObject;
 231     int ret = 0;
 232
 233     TRACE("(lpTable=%p, handle=%ld)\n", lpTable, handle);
 234
 235     EnterCriticalSection(&lpTable->mutex);
 236
 237     if (!is_valid_handle(lpTable, handle, dwType))
 238         goto exit;
 239
 240     pObject = lpTable->paEntries[index].pObject;
 241     if (InterlockedDecrement(&pObject->refcount) == 0)
 242     {
 243         TRACE("destroying handle %ld\n", handle);
 244         if (pObject->destructor)
 245             pObject->destructor(pObject);
 246     }
 247
 248     lpTable->paEntries[index].pObject = NULL;
 249     lpTable->paEntries[index].iNextFree = lpTable->iFirstFree;
 250     lpTable->iFirstFree = index;
 251
 252     ret = 1;
 253 exit:
 254     LeaveCriticalSection(&lpTable->mutex);
 255     return ret;
 256 }
 257
 258 /******************************************************************************
 259  *  lookup_handle
 260  *
 261  * Returns the object identified by the handle in the given handle table
 262  *
 263  * PARAMS
 264  *  lpTable    [I] Pointer to the handle table, in which the handle is looked up.
 265  *  handle     [I] The handle, which is to be looked up
 266  *    lplpObject [O] Pointer to the variable, into which the pointer to the
 267  *                   object looked up is copied.
 268  * RETURNS
 269  *  non zero,  if successful
 270  *  zero,      if not successful (invalid handle)
 271  */
 272 int lookup_handle(struct handle_table *lpTable, HCRYPTKEY handle, DWORD dwType, OBJECTHDR **lplpObject)
 273 {
 274     int ret = 0;
 275
 276     TRACE("(lpTable=%p, handle=%ld, lplpObject=%p)\n", lpTable, handle, lplpObject);
 277
 278     EnterCriticalSection(&lpTable->mutex);
 279     if (!is_valid_handle(lpTable, handle, dwType))
 280     {
 281         *lplpObject = NULL;
 282         goto exit;
 283     }
 284     *lplpObject = lpTable->paEntries[HANDLE2INDEX(handle)].pObject;
 285
 286     ret = 1;
 287 exit:
 288     LeaveCriticalSection(&lpTable->mutex);
 289     return ret;
 290 }
 291
 292 /******************************************************************************
 293  *  copy_handle
 294  *
 295  * Copies a handle. Increments the reference count of the object referenced
 296  * by the handle.
 297  *
 298  * PARAMS
 299  *  lpTable [I] Pointer to the handle table, which holds the handle to be copied.
 300  *  handle  [I] The handle to be copied.
 301  *  copy    [O] Pointer to a handle variable, where the copied handle is put.
 302  *
 303  * RETURNS
 304  *  non zero,  if successful
 305  *  zero,      if not successful (invalid handle or out of memory)
 306  */
 307 int copy_handle(struct handle_table *lpTable, HCRYPTKEY handle, DWORD dwType, HCRYPTKEY *copy)
 308 {
 309     OBJECTHDR *pObject;
 310     int ret;
 311
 312     TRACE("(lpTable=%p, handle=%ld, copy=%p)\n", lpTable, handle, copy);
 313
 314     EnterCriticalSection(&lpTable->mutex);
 315     if (!lookup_handle(lpTable, handle, dwType, &pObject))
 316     {
 317         *copy = (HCRYPTKEY)INVALID_HANDLE_VALUE;
 318         LeaveCriticalSection(&lpTable->mutex);
 319         return 0;
 320     }
 321
 322     ret = alloc_handle(lpTable, pObject, copy);
 323     LeaveCriticalSection(&lpTable->mutex);
 324     return ret;
 325 }
 326
 327 /******************************************************************************
 328  *  new_object
 329  *
 330  * Allocates a new object of size cbSize on the current process's heap.
 331  * Initializes the object header using the destructor and dwType params.
 332  * Allocates a handle to the object in the handle table pointed to by lpTable.
 333  * Returns a pointer to the created object in ppObject.
 334  * Returns a handle to the created object.
 335  *
 336  * PARAMS
 337  *  lpTable    [I] Pointer to the handle table, from which a handle is to be
 338  *              allocated.
 339  *  cbSize     [I] Size of the object to be allocated in bytes.
 340  *  dwType     [I] Object type; will be copied to the object header.
 341  *  destructor [I] Function pointer to a destructor function. Will be called
 342  *                 once the object's reference count gets zero.
 343  *  ppObject   [O] Pointer to a pointer variable, where a pointer to the newly
 344  *                 created object will be stored. You may set this to NULL.
 345  *
 346  * RETURNS
 347  *  INVALID_HANDLE_VALUE,        if something went wrong.
 348  *  a handle to the new object,  if successful.
 349  */
 350 HCRYPTKEY new_object(struct handle_table *lpTable, size_t cbSize, DWORD dwType, DESTRUCTOR destructor,
 351                         OBJECTHDR **ppObject)
 352 {
 353     OBJECTHDR *pObject;
 354     HCRYPTKEY hObject;
 355
 356     if (ppObject)
 357         *ppObject = NULL;
 358
 359     pObject = HeapAlloc(GetProcessHeap(), 0, cbSize);
 360     if (!pObject)
 361         return (HCRYPTKEY)INVALID_HANDLE_VALUE;
 362
 363     pObject->dwType = dwType;
 364     pObject->refcount = 0;
 365     pObject->destructor = destructor;
 366
 367     if (!alloc_handle(lpTable, pObject, &hObject))
 368         HeapFree(GetProcessHeap(), 0, pObject);
 369     else
 370         if (ppObject)
 371             *ppObject = pObject;
 372
 373     return hObject;
 374 }