reactos/ntoskrnl/ob/dirobj.c

   1 /* $Id: dirobj.c,v 1.14 2002/03/17 17:51:33 hbirr Exp $
   2  *
   3  * COPYRIGHT:      See COPYING in the top level directory
   4  * PROJECT:        ReactOS kernel
   5  * FILE:           ntoskrnl/ob/dirobj.c
   6  * PURPOSE:        Interface functions to directory object
   7  * PROGRAMMER:     David Welch (welch@mcmail.com)
   8  * UPDATE HISTORY:
   9  *                 22/05/98: Created
  10  */
  11
  12 /* INCLUDES ***************************************************************/
  13
  14 #include <ddk/ntddk.h>
  15 #include <internal/ob.h>
  16 #include <internal/io.h>
  17
  18 #define NDEBUG
  19 #include <internal/debug.h>
  20
  21
  22 /* FUNCTIONS **************************************************************/
  23
  24
  25 /**********************************************************************
  26  * NAME                                                 EXPORTED
  27  *      NtOpenDirectoryObject
  28  *
  29  * DESCRIPTION
  30  *      Opens a namespace directory object.
  31  *
  32  * ARGUMENTS
  33  *      DirectoryHandle (OUT)
  34  *              Variable which receives the directory handle.
  35  *
  36  *      DesiredAccess
  37  *              Desired access to the directory.
  38  *
  39  *      ObjectAttributes
  40  *              Structure describing the directory.
  41  *
  42  * RETURN VALUE
  43  *      Status.
  44  *
  45  * NOTES
  46  *      Undocumented.
  47  */
  48 NTSTATUS STDCALL NtOpenDirectoryObject(PHANDLE DirectoryHandle,
  49                                        ACCESS_MASK DesiredAccess,
  50                                        POBJECT_ATTRIBUTES ObjectAttributes)
  51 {
  52    PVOID Object;
  53    NTSTATUS Status;
  54
  55    *DirectoryHandle = 0;
  56
  57    Status = ObReferenceObjectByName(ObjectAttributes->ObjectName,
  58                                     ObjectAttributes->Attributes,
  59                                     NULL,
  60                                     DesiredAccess,
  61                                     ObDirectoryType,
  62                                     UserMode,
  63                                     NULL,
  64                                     &Object);
  65    if (!NT_SUCCESS(Status))
  66      {
  67         return Status;
  68      }
  69
  70    Status = ObCreateHandle(PsGetCurrentProcess(),
  71                            Object,
  72                            DesiredAccess,
  73                            FALSE,
  74                            DirectoryHandle);
  75    return STATUS_SUCCESS;
  76 }
  77
  78
  79 /**********************************************************************
  80  * NAME                                                 EXPORTED
  81  *      NtQueryDirectoryObject
  82  *
  83  * DESCRIPTION
  84  *      Reads information from a directory in the system namespace.
  85  *
  86  * ARGUMENTS
  87  *      DirObjHandle
  88  *              Handle, obtained with NtOpenDirectoryObject(), which
  89  *              must grant DIRECTORY_QUERY access to the directory
  90  *              object.
  91  *
  92  *      DirObjInformation (OUT)
  93  *              Buffer to hold the data read.
  94  *
  95  *      BufferLength
  96  *              Size of the buffer in bytes.
  97  *
  98  *      ReturnSingleEntry
  99  *              When TRUE, only 1 entry is written in DirObjInformation;
 100  *              otherwise as many as will fit in the buffer.
 101  *
 102  *      RestartScan
 103  *              If TRUE start reading at index 0.
 104  *              If FALSE start reading at the index specified
 105  *              by object index *ObjectIndex.
 106  *
 107  *      ObjectIndex
 108  *              Zero based index into the directory, interpretation
 109  *              depends on RestartScan.
 110  *
 111  *      DataWritten (OUT)
 112  *              Caller supplied storage for the number of bytes
 113  *              written (or NULL).
 114  *
 115  * RETURN VALUE
 116  *      Status.
 117  *
 118  * REVISIONS
 119  *      2001-05-01 (ea)
 120  *              Changed 4th, and 5th parameter names after
 121  *              G.Nebbett "WNT/W2k Native API Reference".
 122  *              Mostly rewritten.
 123  */
 124 NTSTATUS STDCALL NtQueryDirectoryObject (IN HANDLE DirObjHandle,
 125                                          OUT POBJDIR_INFORMATION
 126                                                     DirObjInformation,
 127                                          IN ULONG BufferLength,
 128                                          IN BOOLEAN ReturnSingleEntry,
 129                                          IN BOOLEAN RestartScan,
 130                                          IN OUT PULONG ObjectIndex,
 131                                          OUT PULONG DataWritten OPTIONAL)
 132 {
 133     PDIRECTORY_OBJECT   dir = NULL;
 134     PLIST_ENTRY         current_entry = NULL;
 135     POBJECT_HEADER      current = NULL;
 136     ULONG               i = 0;
 137     NTSTATUS            Status = STATUS_SUCCESS;
 138     DWORD               DirectoryCount = 0;
 139     DWORD               DirectorySize = 0;
 140     ULONG               SpaceLeft = BufferLength;
 141     ULONG               SpaceRequired = 0;
 142     ULONG               NameLength = 0;
 143     ULONG               TypeNameLength = 0;
 144     POBJDIR_INFORMATION current_odi = DirObjInformation;
 145     PBYTE               FirstFree = (PBYTE) DirObjInformation;
 146
 147
 148     DPRINT("NtQueryDirectoryObject(DirObjHandle %x)\n", DirObjHandle);
 149
 150     /* FIXME: if previous mode == user, use ProbeForWrite
 151      * on user params. */
 152
 153     /* Reference the DIRECTORY_OBJECT */
 154     Status = ObReferenceObjectByHandle(DirObjHandle,
 155                                       DIRECTORY_QUERY,
 156                                       ObDirectoryType,
 157                                       UserMode,
 158                                       (PVOID*)&dir,
 159                                       NULL);
 160     if (!NT_SUCCESS(Status))
 161       {
 162         return (Status);
 163       }
 164     /* Check ObjectIndex is not NULL */
 165     if (NULL == ObjectIndex)
 166       {
 167         return (STATUS_INVALID_PARAMETER);
 168       }
 169     /*
 170      * Compute the number of directory entries
 171      * and the size of the array (in bytes).
 172      * One more entry marks the end of the array.
 173      */
 174     if (FALSE == ReturnSingleEntry)
 175     {
 176         for ( current_entry = dir->head.Flink;
 177               (current_entry != & dir->head);
 178               current_entry = current_entry->Flink
 179               )
 180         {
 181           ++ DirectoryCount;
 182         }
 183     }
 184     else
 185     {
 186         DirectoryCount = 1;
 187     }
 188     // count is DirectoryCount + one null entry
 189     DirectorySize = (DirectoryCount + 1) * sizeof (OBJDIR_INFORMATION);
 190     if (DirectorySize > SpaceLeft)
 191     {
 192         return (STATUS_BUFFER_TOO_SMALL);
 193     }
 194     /*
 195      * Optionally, skip over some entries at the start of the directory
 196      * (use *ObjectIndex value)
 197      */
 198     current_entry = dir->head.Flink;
 199     if (FALSE == RestartScan)
 200       {
 201         /* RestartScan == FALSE */
 202         register ULONG EntriesToSkip = *ObjectIndex;
 203
 204         CHECKPOINT;
 205
 206         for (   ;
 207                 ((EntriesToSkip --) && (current_entry != & dir->head));
 208                 current_entry = current_entry->Flink
 209                 );
 210         if ((EntriesToSkip) && (current_entry == & dir->head))
 211           {
 212             return (STATUS_NO_MORE_ENTRIES);
 213           }
 214       }
 215     /*
 216      * Initialize the array of OBJDIR_INFORMATION.
 217      */
 218     RtlZeroMemory (FirstFree, DirectorySize);
 219     /*
 220      * Move FirstFree to point to the Unicode strings area
 221      */
 222     FirstFree += DirectorySize;
 223     /*
 224      * Compute how much space is left after allocating the
 225      * array in the user buffer.
 226      */
 227     SpaceLeft -= DirectorySize;
 228     /* Scan the directory */
 229     do
 230     {
 231         /*
 232          * Check if we reached the end of the directory.
 233          */
 234         if (current_entry == & dir->head)
 235           {
 236       /* Any data? */
 237             if (i) break; /* DONE */
 238             /* FIXME: better error handling here! */
 239             return (STATUS_NO_MORE_ENTRIES);
 240           }
 241   /*
 242          * Compute the current OBJECT_HEADER memory
 243          * object's address.
 244          */
 245    current = CONTAINING_RECORD(current_entry, OBJECT_HEADER, Entry);
 246   /*
 247    * Compute the space required in the user buffer to copy
 248    * the data from the current object:
 249          *
 250          * Name (WCHAR) 0 TypeName (WCHAR) 0
 251    */
 252         NameLength = (wcslen (current->Name.Buffer) * sizeof (WCHAR));
 253         TypeNameLength = (wcslen (current->ObjectType->TypeName.Buffer) * sizeof (WCHAR));
 254   SpaceRequired = (NameLength + 1) * sizeof (WCHAR)
 255     + (TypeNameLength + 1) * sizeof (WCHAR);
 256         /*
 257          * Check for free space in the user buffer.
 258          */
 259         if (SpaceRequired > SpaceLeft)
 260         {
 261                 return (STATUS_BUFFER_TOO_SMALL);
 262         }
 263   /*
 264    * Copy the current directory entry's data into the buffer
 265          * and update the OBJDIR_INFORMATION entry in the array.
 266    */
 267         /* --- Object's name --- */
 268         current_odi->ObjectName.Length        = NameLength;
 269         current_odi->ObjectName.MaximumLength = (NameLength + sizeof (WCHAR));
 270         current_odi->ObjectName.Buffer        = (PWCHAR) FirstFree;
 271         wcscpy ((PWCHAR) FirstFree, current->Name.Buffer);
 272         FirstFree += (current_odi->ObjectName.MaximumLength);
 273         /* --- Object type's name --- */
 274         current_odi->ObjectTypeName.Length        = TypeNameLength;
 275         current_odi->ObjectTypeName.MaximumLength = (TypeNameLength + sizeof (WCHAR));
 276         current_odi->ObjectTypeName.Buffer        = (PWCHAR) FirstFree;
 277         wcscpy ((PWCHAR) FirstFree, current->ObjectType->TypeName.Buffer);
 278         FirstFree += (current_odi->ObjectTypeName.MaximumLength);
 279         /* Next entry in the array */
 280         ++ current_odi;
 281         /* Decrease the space left count */
 282         SpaceLeft -= SpaceRequired;
 283         /* Increase the object index number */
 284         ++ i;
 285         /* Next object in the directory */
 286         current_entry = current_entry->Flink;
 287
 288     } while (FALSE == ReturnSingleEntry);
 289     /*
 290      * Store current index in ObjectIndex
 291      */
 292     *ObjectIndex += DirectoryCount;
 293     /*
 294      * Report to the caller how much bytes
 295      * we wrote in the user buffer.
 296      */
 297     if (NULL != DataWritten)
 298       {
 299         *DataWritten = (BufferLength - SpaceLeft);
 300       }
 301     return (STATUS_SUCCESS);
 302 }
 303
 304
 305 /**********************************************************************
 306  * NAME                                         (EXPORTED as Zw)
 307  *      NtCreateDirectoryObject
 308  *
 309  * DESCRIPTION
 310  *      Creates or opens a directory object (a container for other
 311  *      objects).
 312  *
 313  * ARGUMENTS
 314  *      DirectoryHandle (OUT)
 315  *              Caller supplied storage for the handle of the
 316  *              directory.
 317  *
 318  *      DesiredAccess
 319  *              Access desired to the directory.
 320  *
 321  *      ObjectAttributes
 322  *              Object attributes initialized with
 323  *              InitializeObjectAttributes.
 324  *
 325  * RETURN VALUE
 326  *      Status.
 327  */
 328 NTSTATUS STDCALL
 329 NtCreateDirectoryObject(PHANDLE DirectoryHandle,
 330                         ACCESS_MASK DesiredAccess,
 331                         POBJECT_ATTRIBUTES ObjectAttributes)
 332 {
 333    PDIRECTORY_OBJECT dir;
 334
 335    DPRINT("NtCreateDirectoryObject(DirectoryHandle %x, "
 336           "DesiredAccess %x, ObjectAttributes %x, "
 337           "ObjectAttributes->ObjectName %S)\n",
 338           DirectoryHandle, DesiredAccess, ObjectAttributes,
 339           ObjectAttributes->ObjectName);
 340
 341    return(ObCreateObject(DirectoryHandle,
 342                          DesiredAccess,
 343                          ObjectAttributes,
 344                          ObDirectoryType,
 345                          (PVOID*)&dir));
 346 }
 347
 348 /* EOF */