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