reactos/ntoskrnl/ob/symlink.c

   1 /* $Id$
   2  *
   3  * COPYRIGHT:       See COPYING in the top level directory
   4  * PROJECT:         ReactOS kernel
   5  * FILE:            ntoskrnl/ob/symlink.c
   6  * PURPOSE:         Implements symbolic links
   7  * PROGRAMMER:      David Welch (welch@mcmail.com)
   8  * UPDATE HISTORY:
   9  *                  Created 22/05/98
  10  */
  11
  12 /* INCLUDES *****************************************************************/
  13
  14 #include <ntoskrnl.h>
  15 #define NDEBUG
  16 #include <internal/debug.h>
  17
  18
  19 /* GLOBALS ******************************************************************/
  20
  21 POBJECT_TYPE ObSymbolicLinkType = NULL;
  22
  23 static GENERIC_MAPPING ObpSymbolicLinkMapping = {
  24         STANDARD_RIGHTS_READ|SYMBOLIC_LINK_QUERY,
  25         STANDARD_RIGHTS_WRITE,
  26         STANDARD_RIGHTS_EXECUTE|SYMBOLIC_LINK_QUERY,
  27         SYMBOLIC_LINK_ALL_ACCESS};
  28
  29 #define TAG_SYMLINK_TTARGET     TAG('S', 'Y', 'T', 'T')
  30 #define TAG_SYMLINK_TARGET      TAG('S', 'Y', 'M', 'T')
  31
  32
  33 /* FUNCTIONS ****************************************************************/
  34
  35 /**********************************************************************
  36  * NAME                                                 INTERNAL
  37  *      ObpCreateSymbolicLink
  38  *
  39  * DESCRIPTION
  40  *
  41  * ARGUMENTS
  42  *
  43  * RETURNN VALUE
  44  *      Status.
  45  *
  46  * REVISIONS
  47  */
  48 NTSTATUS STDCALL
  49 ObpCreateSymbolicLink(PVOID Object,
  50                       PVOID Parent,
  51                       PWSTR RemainingPath,
  52                       POBJECT_ATTRIBUTES ObjectAttributes)
  53 {
  54   return(STATUS_SUCCESS);
  55 }
  56
  57
  58 /**********************************************************************
  59  * NAME                                                 INTERNAL
  60  *      ObpDeleteSymbolicLink
  61  *
  62  * DESCRIPTION
  63  *
  64  * ARGUMENTS
  65  *
  66  * RETURNN VALUE
  67  *      Status.
  68  *
  69  * REVISIONS
  70  */
  71 VOID STDCALL
  72 ObpDeleteSymbolicLink(PVOID ObjectBody)
  73 {
  74   PSYMLINK_OBJECT SymlinkObject = (PSYMLINK_OBJECT)ObjectBody;
  75
  76   RtlFreeUnicodeString(&SymlinkObject->TargetName);
  77 }
  78
  79
  80 /**********************************************************************
  81  * NAME                                                 INTERNAL
  82  *      ObpParseSymbolicLink
  83  *
  84  * DESCRIPTION
  85  *
  86  * ARGUMENTS
  87  *
  88  * RETURN VALUE
  89  *
  90  * REVISIONS
  91  */
  92 NTSTATUS STDCALL
  93 ObpParseSymbolicLink(PVOID Object,
  94                      PVOID * NextObject,
  95                      PUNICODE_STRING FullPath,
  96                      PWSTR * RemainingPath,
  97                      ULONG Attributes)
  98 {
  99   PSYMLINK_OBJECT SymlinkObject = (PSYMLINK_OBJECT) Object;
 100   UNICODE_STRING TargetPath;
 101
 102   DPRINT("ObpParseSymbolicLink (RemainingPath %S)\n", *RemainingPath);
 103
 104   /*
 105    * Stop parsing if the entire path has been parsed and
 106    * the desired object is a symbolic link object.
 107    */
 108   if (((*RemainingPath == NULL) || (**RemainingPath == 0)) &&
 109       (Attributes & OBJ_OPENLINK))
 110     {
 111       DPRINT("Parsing stopped!\n");
 112       *NextObject = NULL;
 113       return(STATUS_SUCCESS);
 114     }
 115
 116    /* build the expanded path */
 117    TargetPath.MaximumLength = SymlinkObject->TargetName.Length + sizeof(WCHAR);
 118    if (RemainingPath && *RemainingPath)
 119      {
 120         TargetPath.MaximumLength += (wcslen(*RemainingPath) * sizeof(WCHAR));
 121      }
 122    TargetPath.Length = TargetPath.MaximumLength - sizeof(WCHAR);
 123    TargetPath.Buffer = ExAllocatePoolWithTag(NonPagedPool,
 124                                              TargetPath.MaximumLength,
 125                                              TAG_SYMLINK_TTARGET);
 126    wcscpy(TargetPath.Buffer, SymlinkObject->TargetName.Buffer);
 127    if (RemainingPath && *RemainingPath)
 128      {
 129         wcscat(TargetPath.Buffer, *RemainingPath);
 130      }
 131
 132    /* transfer target path buffer into FullPath */
 133    RtlFreeUnicodeString(FullPath);
 134    FullPath->Length = TargetPath.Length;
 135    FullPath->MaximumLength = TargetPath.MaximumLength;
 136    FullPath->Buffer = TargetPath.Buffer;
 137
 138    /* reinitialize RemainingPath for reparsing */
 139    *RemainingPath = FullPath->Buffer;
 140
 141    *NextObject = NULL;
 142    return STATUS_REPARSE;
 143 }
 144
 145
 146 /**********************************************************************
 147  * NAME                                                 INTERNAL
 148  *      ObInitSymbolicLinkImplementation
 149  *
 150  * DESCRIPTION
 151  *
 152  * ARGUMENTS
 153  *      None.
 154  *
 155  * RETURNN VALUE
 156  *      None.
 157  *
 158  * REVISIONS
 159  */
 160 VOID INIT_FUNCTION
 161 ObInitSymbolicLinkImplementation (VOID)
 162 {
 163   ObSymbolicLinkType = ExAllocatePool(NonPagedPool, sizeof(OBJECT_TYPE));
 164
 165   ObSymbolicLinkType->Tag = TAG('S', 'Y', 'M', 'T');
 166   ObSymbolicLinkType->TotalObjects = 0;
 167   ObSymbolicLinkType->TotalHandles = 0;
 168   ObSymbolicLinkType->PeakObjects = 0;
 169   ObSymbolicLinkType->PeakHandles = 0;
 170   ObSymbolicLinkType->PagedPoolCharge = 0;
 171   ObSymbolicLinkType->NonpagedPoolCharge = sizeof(SYMLINK_OBJECT);
 172   ObSymbolicLinkType->Mapping = &ObpSymbolicLinkMapping;
 173   ObSymbolicLinkType->Dump = NULL;
 174   ObSymbolicLinkType->Open = NULL;
 175   ObSymbolicLinkType->Close = NULL;
 176   ObSymbolicLinkType->Delete = ObpDeleteSymbolicLink;
 177   ObSymbolicLinkType->Parse = ObpParseSymbolicLink;
 178   ObSymbolicLinkType->Security = NULL;
 179   ObSymbolicLinkType->QueryName = NULL;
 180   ObSymbolicLinkType->OkayToClose = NULL;
 181   ObSymbolicLinkType->Create = ObpCreateSymbolicLink;
 182   ObSymbolicLinkType->DuplicationNotify = NULL;
 183
 184   RtlRosInitUnicodeStringFromLiteral(&ObSymbolicLinkType->TypeName,
 185                                   L"SymbolicLink");
 186
 187   ObpCreateTypeObject(ObSymbolicLinkType);
 188 }
 189
 190
 191 /**********************************************************************
 192  * NAME                                         EXPORTED
 193  *      NtCreateSymbolicLinkObject
 194  *
 195  * DESCRIPTION
 196  *
 197  * ARGUMENTS
 198  *
 199  * RETURN VALUE
 200  *
 201  * REVISIONS
 202  *
 203  */
 204 NTSTATUS STDCALL
 205 NtCreateSymbolicLinkObject(OUT PHANDLE LinkHandle,
 206                            IN ACCESS_MASK DesiredAccess,
 207                            IN POBJECT_ATTRIBUTES ObjectAttributes,
 208                            IN PUNICODE_STRING LinkTarget)
 209 {
 210   PSYMLINK_OBJECT SymbolicLink;
 211   NTSTATUS Status;
 212
 213   ASSERT_IRQL(PASSIVE_LEVEL);
 214
 215   DPRINT("NtCreateSymbolicLinkObject(LinkHandle %p, DesiredAccess %ul, ObjectAttributes %p, LinkTarget %wZ)\n",
 216          LinkHandle,
 217          DesiredAccess,
 218          ObjectAttributes,
 219          LinkTarget);
 220
 221   Status = ObCreateObject(ExGetPreviousMode(),
 222                           ObSymbolicLinkType,
 223                           ObjectAttributes,
 224                           ExGetPreviousMode(),
 225                           NULL,
 226                           sizeof(SYMLINK_OBJECT),
 227                           0,
 228                           0,
 229                           (PVOID*)&SymbolicLink);
 230   if (!NT_SUCCESS(Status))
 231     {
 232       return(Status);
 233     }
 234
 235   Status = ObInsertObject ((PVOID)SymbolicLink,
 236                            NULL,
 237                            DesiredAccess,
 238                            0,
 239                            NULL,
 240                            LinkHandle);
 241   if (!NT_SUCCESS(Status))
 242     {
 243       ObDereferenceObject (SymbolicLink);
 244       return Status;
 245     }
 246
 247   SymbolicLink->TargetName.Length = 0;
 248   SymbolicLink->TargetName.MaximumLength =
 249     ((wcslen(LinkTarget->Buffer) + 1) * sizeof(WCHAR));
 250   SymbolicLink->TargetName.Buffer =
 251     ExAllocatePoolWithTag(NonPagedPool,
 252                           SymbolicLink->TargetName.MaximumLength,
 253                           TAG_SYMLINK_TARGET);
 254   RtlCopyUnicodeString(&SymbolicLink->TargetName,
 255                        LinkTarget);
 256
 257   DPRINT("DeviceName %S\n", SymbolicLink->TargetName.Buffer);
 258
 259   NtQuerySystemTime (&SymbolicLink->CreateTime);
 260
 261   DPRINT("%s() = STATUS_SUCCESS\n",__FUNCTION__);
 262   ObDereferenceObject(SymbolicLink);
 263
 264   return(STATUS_SUCCESS);
 265 }
 266
 267
 268 /**********************************************************************
 269  * NAME                                                 EXPORTED
 270  *      NtOpenSymbolicLinkObject
 271  *
 272  * DESCRIPTION
 273  *
 274  * ARGUMENTS
 275  *
 276  * RETURN VALUE
 277  *
 278  * REVISIONS
 279  *
 280  */
 281 NTSTATUS STDCALL
 282 NtOpenSymbolicLinkObject(OUT PHANDLE LinkHandle,
 283                          IN ACCESS_MASK DesiredAccess,
 284                          IN POBJECT_ATTRIBUTES ObjectAttributes)
 285 {
 286   DPRINT("NtOpenSymbolicLinkObject (Name %wZ)\n",
 287          ObjectAttributes->ObjectName);
 288
 289   return(ObOpenObjectByName(ObjectAttributes,
 290                             ObSymbolicLinkType,
 291                             NULL,
 292                             (KPROCESSOR_MODE)KeGetPreviousMode(),
 293                             DesiredAccess,
 294                             NULL,
 295                             LinkHandle));
 296 }
 297
 298
 299 /**********************************************************************
 300  * NAME                                                 EXPORTED
 301  *      NtQuerySymbolicLinkObject
 302  *
 303  * DESCRIPTION
 304  *
 305  * ARGUMENTS
 306  *
 307  * RETURN VALUE
 308  *
 309  * REVISIONS
 310  *
 311  */
 312 NTSTATUS STDCALL
 313 NtQuerySymbolicLinkObject(IN HANDLE LinkHandle,
 314                           OUT PUNICODE_STRING LinkTarget,
 315                           OUT PULONG ResultLength  OPTIONAL)
 316 {
 317   PSYMLINK_OBJECT SymlinkObject;
 318   NTSTATUS Status;
 319
 320   Status = ObReferenceObjectByHandle(LinkHandle,
 321                                      SYMBOLIC_LINK_QUERY,
 322                                      ObSymbolicLinkType,
 323                                      (KPROCESSOR_MODE)KeGetPreviousMode(),
 324                                      (PVOID *)&SymlinkObject,
 325                                      NULL);
 326   if (!NT_SUCCESS(Status))
 327     {
 328       return Status;
 329     }
 330
 331   if (ResultLength != NULL)
 332     {
 333       *ResultLength = (ULONG)SymlinkObject->TargetName.Length + sizeof(WCHAR);
 334     }
 335
 336   if (LinkTarget->MaximumLength >= SymlinkObject->TargetName.Length + sizeof(WCHAR))
 337     {
 338       RtlCopyUnicodeString(LinkTarget,
 339                            &SymlinkObject->TargetName);
 340       Status = STATUS_SUCCESS;
 341     }
 342   else
 343     {
 344       Status = STATUS_BUFFER_TOO_SMALL;
 345     }
 346
 347   ObDereferenceObject(SymlinkObject);
 348
 349   return Status;
 350 }
 351
 352 /* EOF */