reactos/ntoskrnl/ob/symlink.c

   1 /* $Id: symlink.c,v 1.6 2003/10/14 14:45:23 ekohl Exp $
   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 <limits.h>
  15 #define NTOS_MODE_KERNEL
  16 #include <ntos.h>
  17 #include <internal/ob.h>
  18
  19 #define NDEBUG
  20 #include <internal/debug.h>
  21
  22
  23 /* GLOBALS ******************************************************************/
  24
  25 POBJECT_TYPE ObSymbolicLinkType = NULL;
  26
  27 static GENERIC_MAPPING ObpSymbolicLinkMapping = {
  28         STANDARD_RIGHTS_READ|SYMBOLIC_LINK_QUERY,
  29         STANDARD_RIGHTS_WRITE,
  30         STANDARD_RIGHTS_EXECUTE|SYMBOLIC_LINK_QUERY,
  31         SYMBOLIC_LINK_ALL_ACCESS};
  32
  33 #define TAG_SYMLINK_TTARGET     TAG('S', 'Y', 'T', 'T')
  34 #define TAG_SYMLINK_TARGET      TAG('S', 'Y', 'M', 'T')
  35
  36
  37 /* FUNCTIONS ****************************************************************/
  38
  39 /**********************************************************************
  40  * NAME                                                 INTERNAL
  41  *      ObpCreateSymbolicLink
  42  *
  43  * DESCRIPTION
  44  *
  45  * ARGUMENTS
  46  *
  47  * RETURNN VALUE
  48  *      Status.
  49  *
  50  * REVISIONS
  51  */
  52 NTSTATUS STDCALL
  53 ObpCreateSymbolicLink(PVOID Object,
  54                       PVOID Parent,
  55                       PWSTR RemainingPath,
  56                       POBJECT_ATTRIBUTES ObjectAttributes)
  57 {
  58   return(STATUS_SUCCESS);
  59 }
  60
  61
  62 /**********************************************************************
  63  * NAME                                                 INTERNAL
  64  *      ObpDeleteSymbolicLink
  65  *
  66  * DESCRIPTION
  67  *
  68  * ARGUMENTS
  69  *
  70  * RETURNN VALUE
  71  *      Status.
  72  *
  73  * REVISIONS
  74  */
  75 VOID STDCALL
  76 ObpDeleteSymbolicLink(PVOID ObjectBody)
  77 {
  78   PSYMLINK_OBJECT SymlinkObject = (PSYMLINK_OBJECT)ObjectBody;
  79
  80   RtlFreeUnicodeString(&SymlinkObject->TargetName);
  81 }
  82
  83
  84 /**********************************************************************
  85  * NAME                                                 INTERNAL
  86  *      ObpParseSymbolicLink
  87  *
  88  * DESCRIPTION
  89  *
  90  * ARGUMENTS
  91  *
  92  * RETURN VALUE
  93  *
  94  * REVISIONS
  95  */
  96 NTSTATUS STDCALL
  97 ObpParseSymbolicLink(PVOID Object,
  98                      PVOID * NextObject,
  99                      PUNICODE_STRING FullPath,
 100                      PWSTR * RemainingPath,
 101                      ULONG Attributes)
 102 {
 103   PSYMLINK_OBJECT SymlinkObject = (PSYMLINK_OBJECT) Object;
 104   UNICODE_STRING TargetPath;
 105
 106   DPRINT("ObpParseSymbolicLink (RemainingPath %S)\n", *RemainingPath);
 107
 108   /*
 109    * Stop parsing if the entire path has been parsed and
 110    * the desired object is a symbolic link object.
 111    */
 112   if (((*RemainingPath == NULL) || (**RemainingPath == 0)) &&
 113       (Attributes & OBJ_OPENLINK))
 114     {
 115       DPRINT("Parsing stopped!\n");
 116       *NextObject = NULL;
 117       return(STATUS_SUCCESS);
 118     }
 119
 120    /* build the expanded path */
 121    TargetPath.MaximumLength = SymlinkObject->TargetName.Length + sizeof(WCHAR);
 122    if (RemainingPath && *RemainingPath)
 123      {
 124         TargetPath.MaximumLength += (wcslen(*RemainingPath) * sizeof(WCHAR));
 125      }
 126    TargetPath.Length = TargetPath.MaximumLength - sizeof(WCHAR);
 127    TargetPath.Buffer = ExAllocatePoolWithTag(NonPagedPool,
 128                                              TargetPath.MaximumLength,
 129                                              TAG_SYMLINK_TTARGET);
 130    wcscpy(TargetPath.Buffer, SymlinkObject->TargetName.Buffer);
 131    if (RemainingPath && *RemainingPath)
 132      {
 133         wcscat(TargetPath.Buffer, *RemainingPath);
 134      }
 135
 136    /* transfer target path buffer into FullPath */
 137    RtlFreeUnicodeString(FullPath);
 138    FullPath->Length = TargetPath.Length;
 139    FullPath->MaximumLength = TargetPath.MaximumLength;
 140    FullPath->Buffer = TargetPath.Buffer;
 141
 142    /* reinitialize RemainingPath for reparsing */
 143    *RemainingPath = FullPath->Buffer;
 144
 145    *NextObject = NULL;
 146    return STATUS_REPARSE;
 147 }
 148
 149
 150 /**********************************************************************
 151  * NAME                                                 INTERNAL
 152  *      ObInitSymbolicLinkImplementation
 153  *
 154  * DESCRIPTION
 155  *
 156  * ARGUMENTS
 157  *      None.
 158  *
 159  * RETURNN VALUE
 160  *      None.
 161  *
 162  * REVISIONS
 163  */
 164 VOID INIT_FUNCTION
 165 ObInitSymbolicLinkImplementation (VOID)
 166 {
 167   ObSymbolicLinkType = ExAllocatePool(NonPagedPool, sizeof(OBJECT_TYPE));
 168
 169   ObSymbolicLinkType->Tag = TAG('S', 'Y', 'M', 'T');
 170   ObSymbolicLinkType->TotalObjects = 0;
 171   ObSymbolicLinkType->TotalHandles = 0;
 172   ObSymbolicLinkType->MaxObjects = ULONG_MAX;
 173   ObSymbolicLinkType->MaxHandles = ULONG_MAX;
 174   ObSymbolicLinkType->PagedPoolCharge = 0;
 175   ObSymbolicLinkType->NonpagedPoolCharge = sizeof(SYMLINK_OBJECT);
 176   ObSymbolicLinkType->Mapping = &ObpSymbolicLinkMapping;
 177   ObSymbolicLinkType->Dump = NULL;
 178   ObSymbolicLinkType->Open = NULL;
 179   ObSymbolicLinkType->Close = NULL;
 180   ObSymbolicLinkType->Delete = ObpDeleteSymbolicLink;
 181   ObSymbolicLinkType->Parse = ObpParseSymbolicLink;
 182   ObSymbolicLinkType->Security = NULL;
 183   ObSymbolicLinkType->QueryName = NULL;
 184   ObSymbolicLinkType->OkayToClose = NULL;
 185   ObSymbolicLinkType->Create = ObpCreateSymbolicLink;
 186   ObSymbolicLinkType->DuplicationNotify = NULL;
 187
 188   RtlInitUnicodeStringFromLiteral(&ObSymbolicLinkType->TypeName,
 189                                   L"SymbolicLink");
 190
 191   ObpCreateTypeObject(ObSymbolicLinkType);
 192 }
 193
 194
 195 /**********************************************************************
 196  * NAME                                         EXPORTED
 197  *      NtCreateSymbolicLinkObject
 198  *
 199  * DESCRIPTION
 200  *
 201  * ARGUMENTS
 202  *
 203  * RETURN VALUE
 204  *
 205  * REVISIONS
 206  *
 207  */
 208 NTSTATUS STDCALL
 209 NtCreateSymbolicLinkObject(OUT PHANDLE SymbolicLinkHandle,
 210                            IN ACCESS_MASK DesiredAccess,
 211                            IN POBJECT_ATTRIBUTES ObjectAttributes,
 212                            IN PUNICODE_STRING DeviceName)
 213 {
 214   PSYMLINK_OBJECT SymbolicLink;
 215   NTSTATUS Status;
 216
 217   assert_irql(PASSIVE_LEVEL);
 218
 219   DPRINT("NtCreateSymbolicLinkObject(SymbolicLinkHandle %p, DesiredAccess %ul, ObjectAttributes %p, DeviceName %wZ)\n",
 220          SymbolicLinkHandle,
 221          DesiredAccess,
 222          ObjectAttributes,
 223          DeviceName);
 224
 225   Status = ObCreateObject(ExGetPreviousMode(),
 226                           ObSymbolicLinkType,
 227                           ObjectAttributes,
 228                           ExGetPreviousMode(),
 229                           NULL,
 230                           sizeof(SYMLINK_OBJECT),
 231                           0,
 232                           0,
 233                           (PVOID*)&SymbolicLink);
 234   if (!NT_SUCCESS(Status))
 235     {
 236       return(Status);
 237     }
 238
 239   Status = ObInsertObject ((PVOID)SymbolicLink,
 240                            NULL,
 241                            DesiredAccess,
 242                            0,
 243                            NULL,
 244                            SymbolicLinkHandle);
 245   if (!NT_SUCCESS(Status))
 246     {
 247       ObDereferenceObject (SymbolicLink);
 248       return Status;
 249     }
 250
 251   SymbolicLink->TargetName.Length = 0;
 252   SymbolicLink->TargetName.MaximumLength =
 253     ((wcslen(DeviceName->Buffer) + 1) * sizeof(WCHAR));
 254   SymbolicLink->TargetName.Buffer =
 255     ExAllocatePoolWithTag(NonPagedPool,
 256                           SymbolicLink->TargetName.MaximumLength,
 257                           TAG_SYMLINK_TARGET);
 258   RtlCopyUnicodeString(&SymbolicLink->TargetName,
 259                        DeviceName);
 260
 261   DPRINT("DeviceName %S\n", SymbolicLink->TargetName.Buffer);
 262
 263   NtQuerySystemTime (&SymbolicLink->CreateTime);
 264
 265   DPRINT("%s() = STATUS_SUCCESS\n",__FUNCTION__);
 266   ObDereferenceObject(SymbolicLink);
 267
 268   return(STATUS_SUCCESS);
 269 }
 270
 271
 272 /**********************************************************************
 273  * NAME                                                 EXPORTED
 274  *      NtOpenSymbolicLinkObject
 275  *
 276  * DESCRIPTION
 277  *
 278  * ARGUMENTS
 279  *
 280  * RETURN VALUE
 281  *
 282  * REVISIONS
 283  *
 284  */
 285 NTSTATUS STDCALL
 286 NtOpenSymbolicLinkObject(OUT PHANDLE LinkHandle,
 287                          IN ACCESS_MASK DesiredAccess,
 288                          IN POBJECT_ATTRIBUTES ObjectAttributes)
 289 {
 290   DPRINT("NtOpenSymbolicLinkObject (Name %wZ)\n",
 291          ObjectAttributes->ObjectName);
 292
 293   return(ObOpenObjectByName(ObjectAttributes,
 294                             ObSymbolicLinkType,
 295                             NULL,
 296                             KeGetPreviousMode(),
 297                             DesiredAccess,
 298                             NULL,
 299                             LinkHandle));
 300 }
 301
 302
 303 /**********************************************************************
 304  * NAME                                                 EXPORTED
 305  *      NtQuerySymbolicLinkObject
 306  *
 307  * DESCRIPTION
 308  *
 309  * ARGUMENTS
 310  *
 311  * RETURN VALUE
 312  *
 313  * REVISIONS
 314  *
 315  */
 316 NTSTATUS STDCALL
 317 NtQuerySymbolicLinkObject(IN HANDLE LinkHandle,
 318                           IN OUT PUNICODE_STRING LinkTarget,
 319                           OUT PULONG ReturnedLength OPTIONAL)
 320 {
 321   PSYMLINK_OBJECT SymlinkObject;
 322   NTSTATUS Status;
 323
 324   Status = ObReferenceObjectByHandle(LinkHandle,
 325                                      SYMBOLIC_LINK_QUERY,
 326                                      ObSymbolicLinkType,
 327                                      KeGetPreviousMode(),
 328                                      (PVOID *)&SymlinkObject,
 329                                      NULL);
 330   if (!NT_SUCCESS(Status))
 331     {
 332       return Status;
 333     }
 334
 335   if (ReturnedLength != NULL)
 336     {
 337       *ReturnedLength = (ULONG)SymlinkObject->TargetName.Length + sizeof(WCHAR);
 338     }
 339
 340   if (LinkTarget->MaximumLength >= SymlinkObject->TargetName.Length + sizeof(WCHAR))
 341     {
 342       RtlCopyUnicodeString(LinkTarget,
 343                            &SymlinkObject->TargetName);
 344       Status = STATUS_SUCCESS;
 345     }
 346   else
 347     {
 348       Status = STATUS_BUFFER_TOO_SMALL;
 349     }
 350
 351   ObDereferenceObject(SymlinkObject);
 352
 353   return Status;
 354 }
 355
 356 /* EOF */